4579 lines
160 KiB
C++
4579 lines
160 KiB
C++
#include "archive.hh"
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#include "derivations.hh"
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#include "downstream-placeholder.hh"
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#include "eval-inline.hh"
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#include "eval.hh"
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#include "eval-settings.hh"
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#include "gc-small-vector.hh"
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#include "globals.hh"
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#include "json-to-value.hh"
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#include "names.hh"
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#include "path-references.hh"
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#include "store-api.hh"
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#include "util.hh"
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#include "processes.hh"
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#include "value-to-json.hh"
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#include "value-to-xml.hh"
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#include "primops.hh"
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#include "fs-input-accessor.hh"
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#include "fetch-to-store.hh"
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#include <boost/container/small_vector.hpp>
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#include <nlohmann/json.hpp>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <unistd.h>
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#include <algorithm>
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#include <cstring>
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#include <regex>
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#include <dlfcn.h>
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#include <cmath>
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namespace nix {
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/*************************************************************
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* Miscellaneous
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*************************************************************/
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InvalidPathError::InvalidPathError(const Path & path) :
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EvalError("path '%s' is not valid", path), path(path) {}
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StringMap EvalState::realiseContext(const NixStringContext & context)
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{
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std::vector<DerivedPath::Built> drvs;
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StringMap res;
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||
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for (auto & c : context) {
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auto ensureValid = [&](const StorePath & p) {
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if (!store->isValidPath(p))
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debugThrowLastTrace(InvalidPathError(store->printStorePath(p)));
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};
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std::visit(overloaded {
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[&](const NixStringContextElem::Built & b) {
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drvs.push_back(DerivedPath::Built {
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.drvPath = b.drvPath,
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.outputs = OutputsSpec::Names { b.output },
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});
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ensureValid(b.drvPath->getBaseStorePath());
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},
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[&](const NixStringContextElem::Opaque & o) {
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auto ctxS = store->printStorePath(o.path);
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res.insert_or_assign(ctxS, ctxS);
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ensureValid(o.path);
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},
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[&](const NixStringContextElem::DrvDeep & d) {
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/* Treat same as Opaque */
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auto ctxS = store->printStorePath(d.drvPath);
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res.insert_or_assign(ctxS, ctxS);
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ensureValid(d.drvPath);
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},
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}, c.raw);
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}
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if (drvs.empty()) return {};
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if (!evalSettings.enableImportFromDerivation)
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debugThrowLastTrace(Error(
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"cannot build '%1%' during evaluation because the option 'allow-import-from-derivation' is disabled",
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drvs.begin()->to_string(*store)));
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/* Build/substitute the context. */
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std::vector<DerivedPath> buildReqs;
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for (auto & d : drvs) buildReqs.emplace_back(DerivedPath { d });
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buildStore->buildPaths(buildReqs, bmNormal, store);
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StorePathSet outputsToCopyAndAllow;
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for (auto & drv : drvs) {
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auto outputs = resolveDerivedPath(*buildStore, drv, &*store);
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for (auto & [outputName, outputPath] : outputs) {
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outputsToCopyAndAllow.insert(outputPath);
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/* Get all the output paths corresponding to the placeholders we had */
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if (experimentalFeatureSettings.isEnabled(Xp::CaDerivations)) {
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res.insert_or_assign(
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DownstreamPlaceholder::fromSingleDerivedPathBuilt(
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SingleDerivedPath::Built {
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.drvPath = drv.drvPath,
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.output = outputName,
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}).render(),
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buildStore->printStorePath(outputPath)
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);
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}
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}
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}
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if (store != buildStore) copyClosure(*buildStore, *store, outputsToCopyAndAllow);
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for (auto & outputPath : outputsToCopyAndAllow) {
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/* Add the output of this derivations to the allowed
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paths. */
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allowPath(outputPath);
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}
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return res;
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}
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static SourcePath realisePath(EvalState & state, const PosIdx pos, Value & v, bool resolveSymlinks = true)
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{
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NixStringContext context;
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auto path = state.coerceToPath(noPos, v, context, "while realising the context of a path");
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try {
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if (!context.empty() && path.accessor == state.rootFS) {
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auto rewrites = state.realiseContext(context);
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auto realPath = state.toRealPath(rewriteStrings(path.path.abs(), rewrites), context);
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path = {path.accessor, CanonPath(realPath)};
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}
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return resolveSymlinks ? path.resolveSymlinks() : path;
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} catch (Error & e) {
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e.addTrace(state.positions[pos], "while realising the context of path '%s'", path);
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throw;
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}
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}
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/**
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* Add and attribute to the given attribute map from the output name to
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* the output path, or a placeholder.
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*
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* Where possible the path is used, but for floating CA derivations we
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* may not know it. For sake of determinism we always assume we don't
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* and instead put in a place holder. In either case, however, the
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* string context will contain the drv path and output name, so
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* downstream derivations will have the proper dependency, and in
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* addition, before building, the placeholder will be rewritten to be
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* the actual path.
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*
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* The 'drv' and 'drvPath' outputs must correspond.
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*/
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static void mkOutputString(
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EvalState & state,
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BindingsBuilder & attrs,
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const StorePath & drvPath,
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const std::pair<std::string, DerivationOutput> & o)
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{
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state.mkOutputString(
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attrs.alloc(o.first),
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SingleDerivedPath::Built {
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.drvPath = makeConstantStorePathRef(drvPath),
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.output = o.first,
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},
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o.second.path(*state.store, Derivation::nameFromPath(drvPath), o.first));
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}
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/* Load and evaluate an expression from path specified by the
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argument. */
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static void import(EvalState & state, const PosIdx pos, Value & vPath, Value * vScope, Value & v)
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{
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auto path = realisePath(state, pos, vPath, false);
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auto path2 = path.path.abs();
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// FIXME
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auto isValidDerivationInStore = [&]() -> std::optional<StorePath> {
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if (!state.store->isStorePath(path2))
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return std::nullopt;
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auto storePath = state.store->parseStorePath(path2);
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if (!(state.store->isValidPath(storePath) && isDerivation(path2)))
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return std::nullopt;
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return storePath;
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};
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if (auto storePath = isValidDerivationInStore()) {
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Derivation drv = state.store->readDerivation(*storePath);
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auto attrs = state.buildBindings(3 + drv.outputs.size());
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attrs.alloc(state.sDrvPath).mkString(path2, {
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NixStringContextElem::DrvDeep { .drvPath = *storePath },
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});
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attrs.alloc(state.sName).mkString(drv.env["name"]);
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auto & outputsVal = attrs.alloc(state.sOutputs);
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state.mkList(outputsVal, drv.outputs.size());
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for (const auto & [i, o] : enumerate(drv.outputs)) {
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mkOutputString(state, attrs, *storePath, o);
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(outputsVal.listElems()[i] = state.allocValue())->mkString(o.first);
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}
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auto w = state.allocValue();
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w->mkAttrs(attrs);
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if (!state.vImportedDrvToDerivation) {
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state.vImportedDrvToDerivation = allocRootValue(state.allocValue());
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state.eval(state.parseExprFromString(
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#include "imported-drv-to-derivation.nix.gen.hh"
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, state.rootPath(CanonPath::root)), **state.vImportedDrvToDerivation);
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}
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state.forceFunction(**state.vImportedDrvToDerivation, pos, "while evaluating imported-drv-to-derivation.nix.gen.hh");
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v.mkApp(*state.vImportedDrvToDerivation, w);
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state.forceAttrs(v, pos, "while calling imported-drv-to-derivation.nix.gen.hh");
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}
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else {
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if (!vScope)
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state.evalFile(path, v);
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else {
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state.forceAttrs(*vScope, pos, "while evaluating the first argument passed to builtins.scopedImport");
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Env * env = &state.allocEnv(vScope->attrs->size());
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env->up = &state.baseEnv;
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auto staticEnv = std::make_shared<StaticEnv>(nullptr, state.staticBaseEnv.get(), vScope->attrs->size());
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unsigned int displ = 0;
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for (auto & attr : *vScope->attrs) {
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staticEnv->vars.emplace_back(attr.name, displ);
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env->values[displ++] = attr.value;
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}
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// No need to call staticEnv.sort(), because
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// args[0]->attrs is already sorted.
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printTalkative("evaluating file '%1%'", path);
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Expr * e = state.parseExprFromFile(resolveExprPath(path), staticEnv);
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e->eval(state, *env, v);
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}
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}
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}
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static RegisterPrimOp primop_scopedImport(PrimOp {
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.name = "scopedImport",
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.arity = 2,
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.fun = [](EvalState & state, const PosIdx pos, Value * * args, Value & v)
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{
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import(state, pos, *args[1], args[0], v);
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}
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});
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static RegisterPrimOp primop_import({
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.name = "import",
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.args = {"path"},
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// TODO turn "normal path values" into link below
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.doc = R"(
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Load, parse, and return the Nix expression in the file *path*.
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> **Note**
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>
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> Unlike some languages, `import` is a regular function in Nix.
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The *path* argument must meet the same criteria as an [interpolated expression](@docroot@/language/string-interpolation.md#interpolated-expression).
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If *path* is a directory, the file `default.nix` in that directory is used if it exists.
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> **Example**
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>
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> ```console
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> $ echo 123 > default.nix
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> ```
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>
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> Import `default.nix` from the current directory.
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>
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> ```nix
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> import ./.
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> ```
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>
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> 123
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Evaluation aborts if the file doesn’t exist or contains an invalid Nix expression.
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A Nix expression loaded by `import` must not contain any *free variables*, that is, identifiers that are not defined in the Nix expression itself and are not built-in.
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Therefore, it cannot refer to variables that are in scope at the call site.
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> **Example**
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>
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> If you have a calling expression
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>
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> ```nix
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> rec {
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> x = 123;
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> y = import ./foo.nix;
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> }
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> ```
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>
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> then the following `foo.nix` will give an error:
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>
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> ```nix
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> # foo.nix
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> x + 456
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> ```
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>
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> since `x` is not in scope in `foo.nix`.
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> If you want `x` to be available in `foo.nix`, pass it as a function argument:
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>
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> ```nix
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> rec {
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> x = 123;
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> y = import ./foo.nix x;
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> }
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> ```
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>
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> and
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>
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> ```nix
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> # foo.nix
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> x: x + 456
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> ```
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>
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> The function argument doesn’t have to be called `x` in `foo.nix`; any name would work.
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||
)",
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.fun = [](EvalState & state, const PosIdx pos, Value * * args, Value & v)
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{
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import(state, pos, *args[0], nullptr, v);
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}
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});
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/* Want reasonable symbol names, so extern C */
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/* !!! Should we pass the Pos or the file name too? */
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extern "C" typedef void (*ValueInitializer)(EvalState & state, Value & v);
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/* Load a ValueInitializer from a DSO and return whatever it initializes */
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void prim_importNative(EvalState & state, const PosIdx pos, Value * * args, Value & v)
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{
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auto path = realisePath(state, pos, *args[0]);
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std::string sym(state.forceStringNoCtx(*args[1], pos, "while evaluating the second argument passed to builtins.importNative"));
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void *handle = dlopen(path.path.c_str(), RTLD_LAZY | RTLD_LOCAL);
|
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if (!handle)
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state.debugThrowLastTrace(EvalError("could not open '%1%': %2%", path, dlerror()));
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dlerror();
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ValueInitializer func = (ValueInitializer) dlsym(handle, sym.c_str());
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if(!func) {
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char *message = dlerror();
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if (message)
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state.debugThrowLastTrace(EvalError("could not load symbol '%1%' from '%2%': %3%", sym, path, message));
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else
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state.debugThrowLastTrace(EvalError("symbol '%1%' from '%2%' resolved to NULL when a function pointer was expected", sym, path));
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}
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(func)(state, v);
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/* We don't dlclose because v may be a primop referencing a function in the shared object file */
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}
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/* Execute a program and parse its output */
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void prim_exec(EvalState & state, const PosIdx pos, Value * * args, Value & v)
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{
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state.forceList(*args[0], pos, "while evaluating the first argument passed to builtins.exec");
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auto elems = args[0]->listElems();
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auto count = args[0]->listSize();
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if (count == 0)
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state.error("at least one argument to 'exec' required").atPos(pos).debugThrow<EvalError>();
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NixStringContext context;
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auto program = state.coerceToString(pos, *elems[0], context,
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"while evaluating the first element of the argument passed to builtins.exec",
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false, false).toOwned();
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Strings commandArgs;
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for (unsigned int i = 1; i < args[0]->listSize(); ++i) {
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commandArgs.push_back(
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state.coerceToString(pos, *elems[i], context,
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"while evaluating an element of the argument passed to builtins.exec",
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false, false).toOwned());
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||
}
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||
try {
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auto _ = state.realiseContext(context); // FIXME: Handle CA derivations
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} catch (InvalidPathError & e) {
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state.error("cannot execute '%1%', since path '%2%' is not valid", program, e.path).atPos(pos).debugThrow<EvalError>();
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}
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||
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auto output = runProgram(program, true, commandArgs);
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Expr * parsed;
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try {
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parsed = state.parseExprFromString(std::move(output), state.rootPath(CanonPath::root));
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||
} catch (Error & e) {
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e.addTrace(state.positions[pos], "while parsing the output from '%1%'", program);
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throw;
|
||
}
|
||
try {
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state.eval(parsed, v);
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||
} catch (Error & e) {
|
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e.addTrace(state.positions[pos], "while evaluating the output from '%1%'", program);
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||
throw;
|
||
}
|
||
}
|
||
|
||
/* Return a string representing the type of the expression. */
|
||
static void prim_typeOf(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceValue(*args[0], pos);
|
||
std::string t;
|
||
switch (args[0]->type()) {
|
||
case nInt: t = "int"; break;
|
||
case nBool: t = "bool"; break;
|
||
case nString: t = "string"; break;
|
||
case nPath: t = "path"; break;
|
||
case nNull: t = "null"; break;
|
||
case nAttrs: t = "set"; break;
|
||
case nList: t = "list"; break;
|
||
case nFunction: t = "lambda"; break;
|
||
case nExternal:
|
||
t = args[0]->external->typeOf();
|
||
break;
|
||
case nFloat: t = "float"; break;
|
||
case nThunk: abort();
|
||
}
|
||
v.mkString(t);
|
||
}
|
||
|
||
static RegisterPrimOp primop_typeOf({
|
||
.name = "__typeOf",
|
||
.args = {"e"},
|
||
.doc = R"(
|
||
Return a string representing the type of the value *e*, namely
|
||
`"int"`, `"bool"`, `"string"`, `"path"`, `"null"`, `"set"`,
|
||
`"list"`, `"lambda"` or `"float"`.
|
||
)",
|
||
.fun = prim_typeOf,
|
||
});
|
||
|
||
/* Determine whether the argument is the null value. */
|
||
static void prim_isNull(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceValue(*args[0], pos);
|
||
v.mkBool(args[0]->type() == nNull);
|
||
}
|
||
|
||
static RegisterPrimOp primop_isNull({
|
||
.name = "isNull",
|
||
.args = {"e"},
|
||
.doc = R"(
|
||
Return `true` if *e* evaluates to `null`, and `false` otherwise.
|
||
|
||
This is equivalent to `e == null`.
|
||
)",
|
||
.fun = prim_isNull,
|
||
});
|
||
|
||
/* Determine whether the argument is a function. */
|
||
static void prim_isFunction(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceValue(*args[0], pos);
|
||
v.mkBool(args[0]->type() == nFunction);
|
||
}
|
||
|
||
static RegisterPrimOp primop_isFunction({
|
||
.name = "__isFunction",
|
||
.args = {"e"},
|
||
.doc = R"(
|
||
Return `true` if *e* evaluates to a function, and `false` otherwise.
|
||
)",
|
||
.fun = prim_isFunction,
|
||
});
|
||
|
||
/* Determine whether the argument is an integer. */
|
||
static void prim_isInt(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceValue(*args[0], pos);
|
||
v.mkBool(args[0]->type() == nInt);
|
||
}
|
||
|
||
static RegisterPrimOp primop_isInt({
|
||
.name = "__isInt",
|
||
.args = {"e"},
|
||
.doc = R"(
|
||
Return `true` if *e* evaluates to an integer, and `false` otherwise.
|
||
)",
|
||
.fun = prim_isInt,
|
||
});
|
||
|
||
/* Determine whether the argument is a float. */
|
||
static void prim_isFloat(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceValue(*args[0], pos);
|
||
v.mkBool(args[0]->type() == nFloat);
|
||
}
|
||
|
||
static RegisterPrimOp primop_isFloat({
|
||
.name = "__isFloat",
|
||
.args = {"e"},
|
||
.doc = R"(
|
||
Return `true` if *e* evaluates to a float, and `false` otherwise.
|
||
)",
|
||
.fun = prim_isFloat,
|
||
});
|
||
|
||
/* Determine whether the argument is a string. */
|
||
static void prim_isString(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceValue(*args[0], pos);
|
||
v.mkBool(args[0]->type() == nString);
|
||
}
|
||
|
||
static RegisterPrimOp primop_isString({
|
||
.name = "__isString",
|
||
.args = {"e"},
|
||
.doc = R"(
|
||
Return `true` if *e* evaluates to a string, and `false` otherwise.
|
||
)",
|
||
.fun = prim_isString,
|
||
});
|
||
|
||
/* Determine whether the argument is a Boolean. */
|
||
static void prim_isBool(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceValue(*args[0], pos);
|
||
v.mkBool(args[0]->type() == nBool);
|
||
}
|
||
|
||
static RegisterPrimOp primop_isBool({
|
||
.name = "__isBool",
|
||
.args = {"e"},
|
||
.doc = R"(
|
||
Return `true` if *e* evaluates to a bool, and `false` otherwise.
|
||
)",
|
||
.fun = prim_isBool,
|
||
});
|
||
|
||
/* Determine whether the argument is a path. */
|
||
static void prim_isPath(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceValue(*args[0], pos);
|
||
v.mkBool(args[0]->type() == nPath);
|
||
}
|
||
|
||
static RegisterPrimOp primop_isPath({
|
||
.name = "__isPath",
|
||
.args = {"e"},
|
||
.doc = R"(
|
||
Return `true` if *e* evaluates to a path, and `false` otherwise.
|
||
)",
|
||
.fun = prim_isPath,
|
||
});
|
||
|
||
template<typename Callable>
|
||
static inline void withExceptionContext(Trace trace, Callable&& func)
|
||
{
|
||
try
|
||
{
|
||
func();
|
||
}
|
||
catch(Error & e)
|
||
{
|
||
e.pushTrace(trace);
|
||
throw;
|
||
}
|
||
}
|
||
|
||
struct CompareValues
|
||
{
|
||
EvalState & state;
|
||
const PosIdx pos;
|
||
const std::string_view errorCtx;
|
||
|
||
CompareValues(EvalState & state, const PosIdx pos, const std::string_view && errorCtx) : state(state), pos(pos), errorCtx(errorCtx) { };
|
||
|
||
bool operator () (Value * v1, Value * v2) const
|
||
{
|
||
return (*this)(v1, v2, errorCtx);
|
||
}
|
||
|
||
bool operator () (Value * v1, Value * v2, std::string_view errorCtx) const
|
||
{
|
||
try {
|
||
if (v1->type() == nFloat && v2->type() == nInt)
|
||
return v1->fpoint < v2->integer;
|
||
if (v1->type() == nInt && v2->type() == nFloat)
|
||
return v1->integer < v2->fpoint;
|
||
if (v1->type() != v2->type())
|
||
state.error("cannot compare %s with %s", showType(*v1), showType(*v2)).debugThrow<EvalError>();
|
||
// Allow selecting a subset of enum values
|
||
#pragma GCC diagnostic push
|
||
#pragma GCC diagnostic ignored "-Wswitch-enum"
|
||
switch (v1->type()) {
|
||
case nInt:
|
||
return v1->integer < v2->integer;
|
||
case nFloat:
|
||
return v1->fpoint < v2->fpoint;
|
||
case nString:
|
||
return strcmp(v1->c_str(), v2->c_str()) < 0;
|
||
case nPath:
|
||
// Note: we don't take the accessor into account
|
||
// since it's not obvious how to compare them in a
|
||
// reproducible way.
|
||
return strcmp(v1->_path.path, v2->_path.path) < 0;
|
||
case nList:
|
||
// Lexicographic comparison
|
||
for (size_t i = 0;; i++) {
|
||
if (i == v2->listSize()) {
|
||
return false;
|
||
} else if (i == v1->listSize()) {
|
||
return true;
|
||
} else if (!state.eqValues(*v1->listElems()[i], *v2->listElems()[i], pos, errorCtx)) {
|
||
return (*this)(v1->listElems()[i], v2->listElems()[i], "while comparing two list elements");
|
||
}
|
||
}
|
||
default:
|
||
state.error("cannot compare %s with %s; values of that type are incomparable", showType(*v1), showType(*v2)).debugThrow<EvalError>();
|
||
#pragma GCC diagnostic pop
|
||
}
|
||
} catch (Error & e) {
|
||
if (!errorCtx.empty())
|
||
e.addTrace(nullptr, errorCtx);
|
||
throw;
|
||
}
|
||
}
|
||
};
|
||
|
||
|
||
#if HAVE_BOEHMGC
|
||
typedef std::list<Value *, gc_allocator<Value *>> ValueList;
|
||
#else
|
||
typedef std::list<Value *> ValueList;
|
||
#endif
|
||
|
||
|
||
static Bindings::iterator getAttr(
|
||
EvalState & state,
|
||
Symbol attrSym,
|
||
Bindings * attrSet,
|
||
std::string_view errorCtx)
|
||
{
|
||
Bindings::iterator value = attrSet->find(attrSym);
|
||
if (value == attrSet->end()) {
|
||
state.error("attribute '%s' missing", state.symbols[attrSym]).withTrace(noPos, errorCtx).debugThrow<TypeError>();
|
||
}
|
||
return value;
|
||
}
|
||
|
||
static void prim_genericClosure(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceAttrs(*args[0], noPos, "while evaluating the first argument passed to builtins.genericClosure");
|
||
|
||
/* Get the start set. */
|
||
Bindings::iterator startSet = getAttr(state, state.sStartSet, args[0]->attrs, "in the attrset passed as argument to builtins.genericClosure");
|
||
|
||
state.forceList(*startSet->value, noPos, "while evaluating the 'startSet' attribute passed as argument to builtins.genericClosure");
|
||
|
||
ValueList workSet;
|
||
for (auto elem : startSet->value->listItems())
|
||
workSet.push_back(elem);
|
||
|
||
if (startSet->value->listSize() == 0) {
|
||
v = *startSet->value;
|
||
return;
|
||
}
|
||
|
||
/* Get the operator. */
|
||
Bindings::iterator op = getAttr(state, state.sOperator, args[0]->attrs, "in the attrset passed as argument to builtins.genericClosure");
|
||
state.forceFunction(*op->value, noPos, "while evaluating the 'operator' attribute passed as argument to builtins.genericClosure");
|
||
|
||
/* Construct the closure by applying the operator to elements of
|
||
`workSet', adding the result to `workSet', continuing until
|
||
no new elements are found. */
|
||
ValueList res;
|
||
// `doneKeys' doesn't need to be a GC root, because its values are
|
||
// reachable from res.
|
||
auto cmp = CompareValues(state, noPos, "while comparing the `key` attributes of two genericClosure elements");
|
||
std::set<Value *, decltype(cmp)> doneKeys(cmp);
|
||
while (!workSet.empty()) {
|
||
Value * e = *(workSet.begin());
|
||
workSet.pop_front();
|
||
|
||
state.forceAttrs(*e, noPos, "while evaluating one of the elements generated by (or initially passed to) builtins.genericClosure");
|
||
|
||
Bindings::iterator key = getAttr(state, state.sKey, e->attrs, "in one of the attrsets generated by (or initially passed to) builtins.genericClosure");
|
||
state.forceValue(*key->value, noPos);
|
||
|
||
if (!doneKeys.insert(key->value).second) continue;
|
||
res.push_back(e);
|
||
|
||
/* Call the `operator' function with `e' as argument. */
|
||
Value newElements;
|
||
state.callFunction(*op->value, 1, &e, newElements, noPos);
|
||
state.forceList(newElements, noPos, "while evaluating the return value of the `operator` passed to builtins.genericClosure");
|
||
|
||
/* Add the values returned by the operator to the work set. */
|
||
for (auto elem : newElements.listItems()) {
|
||
state.forceValue(*elem, noPos); // "while evaluating one one of the elements returned by the `operator` passed to builtins.genericClosure");
|
||
workSet.push_back(elem);
|
||
}
|
||
}
|
||
|
||
/* Create the result list. */
|
||
state.mkList(v, res.size());
|
||
unsigned int n = 0;
|
||
for (auto & i : res)
|
||
v.listElems()[n++] = i;
|
||
}
|
||
|
||
static RegisterPrimOp primop_genericClosure(PrimOp {
|
||
.name = "__genericClosure",
|
||
.args = {"attrset"},
|
||
.arity = 1,
|
||
.doc = R"(
|
||
Take an *attrset* with values named `startSet` and `operator` in order to
|
||
return a *list of attrsets* by starting with the `startSet` and recursively
|
||
applying the `operator` function to each `item`. The *attrsets* in the
|
||
`startSet` and the *attrsets* produced by `operator` must contain a value
|
||
named `key` which is comparable. The result is produced by calling `operator`
|
||
for each `item` with a value for `key` that has not been called yet including
|
||
newly produced `item`s. The function terminates when no new `item`s are
|
||
produced. The resulting *list of attrsets* contains only *attrsets* with a
|
||
unique key. For example,
|
||
|
||
```
|
||
builtins.genericClosure {
|
||
startSet = [ {key = 5;} ];
|
||
operator = item: [{
|
||
key = if (item.key / 2 ) * 2 == item.key
|
||
then item.key / 2
|
||
else 3 * item.key + 1;
|
||
}];
|
||
}
|
||
```
|
||
evaluates to
|
||
```
|
||
[ { key = 5; } { key = 16; } { key = 8; } { key = 4; } { key = 2; } { key = 1; } ]
|
||
```
|
||
|
||
`key` can be one of the following types:
|
||
- [Number](@docroot@/language/values.md#type-number)
|
||
- [Boolean](@docroot@/language/values.md#type-boolean)
|
||
- [String](@docroot@/language/values.md#type-string)
|
||
- [Path](@docroot@/language/values.md#type-path)
|
||
- [List](@docroot@/language/values.md#list)
|
||
|
||
)",
|
||
.fun = prim_genericClosure,
|
||
});
|
||
|
||
|
||
static RegisterPrimOp primop_break({
|
||
.name = "break",
|
||
.args = {"v"},
|
||
.doc = R"(
|
||
In debug mode (enabled using `--debugger`), pause Nix expression evaluation and enter the REPL.
|
||
Otherwise, return the argument `v`.
|
||
)",
|
||
.fun = [](EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
if (state.debugRepl && !state.debugTraces.empty()) {
|
||
auto error = Error(ErrorInfo {
|
||
.level = lvlInfo,
|
||
.msg = hintfmt("breakpoint reached"),
|
||
.errPos = state.positions[pos],
|
||
});
|
||
|
||
auto & dt = state.debugTraces.front();
|
||
state.runDebugRepl(&error, dt.env, dt.expr);
|
||
|
||
if (state.debugQuit) {
|
||
// If the user elects to quit the repl, throw an exception.
|
||
throw Error(ErrorInfo{
|
||
.level = lvlInfo,
|
||
.msg = hintfmt("quit the debugger"),
|
||
.errPos = nullptr,
|
||
});
|
||
}
|
||
}
|
||
|
||
// Return the value we were passed.
|
||
v = *args[0];
|
||
}
|
||
});
|
||
|
||
static RegisterPrimOp primop_abort({
|
||
.name = "abort",
|
||
.args = {"s"},
|
||
.doc = R"(
|
||
Abort Nix expression evaluation and print the error message *s*.
|
||
)",
|
||
.fun = [](EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
NixStringContext context;
|
||
auto s = state.coerceToString(pos, *args[0], context,
|
||
"while evaluating the error message passed to builtins.abort").toOwned();
|
||
state.debugThrowLastTrace(Abort("evaluation aborted with the following error message: '%1%'", s));
|
||
}
|
||
});
|
||
|
||
static RegisterPrimOp primop_throw({
|
||
.name = "throw",
|
||
.args = {"s"},
|
||
.doc = R"(
|
||
Throw an error message *s*. This usually aborts Nix expression
|
||
evaluation, but in `nix-env -qa` and other commands that try to
|
||
evaluate a set of derivations to get information about those
|
||
derivations, a derivation that throws an error is silently skipped
|
||
(which is not the case for `abort`).
|
||
)",
|
||
.fun = [](EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
NixStringContext context;
|
||
auto s = state.coerceToString(pos, *args[0], context,
|
||
"while evaluating the error message passed to builtin.throw").toOwned();
|
||
state.debugThrowLastTrace(ThrownError(s));
|
||
}
|
||
});
|
||
|
||
static void prim_addErrorContext(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
try {
|
||
state.forceValue(*args[1], pos);
|
||
v = *args[1];
|
||
} catch (Error & e) {
|
||
NixStringContext context;
|
||
auto message = state.coerceToString(pos, *args[0], context,
|
||
"while evaluating the error message passed to builtins.addErrorContext",
|
||
false, false).toOwned();
|
||
e.addTrace(nullptr, hintfmt(message), true);
|
||
throw;
|
||
}
|
||
}
|
||
|
||
static RegisterPrimOp primop_addErrorContext(PrimOp {
|
||
.name = "__addErrorContext",
|
||
.arity = 2,
|
||
.fun = prim_addErrorContext,
|
||
});
|
||
|
||
static void prim_ceil(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
auto value = state.forceFloat(*args[0], args[0]->determinePos(pos),
|
||
"while evaluating the first argument passed to builtins.ceil");
|
||
v.mkInt(ceil(value));
|
||
}
|
||
|
||
static RegisterPrimOp primop_ceil({
|
||
.name = "__ceil",
|
||
.args = {"double"},
|
||
.doc = R"(
|
||
Converts an IEEE-754 double-precision floating-point number (*double*) to
|
||
the next higher integer.
|
||
|
||
If the datatype is neither an integer nor a "float", an evaluation error will be
|
||
thrown.
|
||
)",
|
||
.fun = prim_ceil,
|
||
});
|
||
|
||
static void prim_floor(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
auto value = state.forceFloat(*args[0], args[0]->determinePos(pos), "while evaluating the first argument passed to builtins.floor");
|
||
v.mkInt(floor(value));
|
||
}
|
||
|
||
static RegisterPrimOp primop_floor({
|
||
.name = "__floor",
|
||
.args = {"double"},
|
||
.doc = R"(
|
||
Converts an IEEE-754 double-precision floating-point number (*double*) to
|
||
the next lower integer.
|
||
|
||
If the datatype is neither an integer nor a "float", an evaluation error will be
|
||
thrown.
|
||
)",
|
||
.fun = prim_floor,
|
||
});
|
||
|
||
/* Try evaluating the argument. Success => {success=true; value=something;},
|
||
* else => {success=false; value=false;} */
|
||
static void prim_tryEval(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
auto attrs = state.buildBindings(2);
|
||
|
||
/* increment state.trylevel, and decrement it when this function returns. */
|
||
MaintainCount trylevel(state.trylevel);
|
||
|
||
void (* savedDebugRepl)(ref<EvalState> es, const ValMap & extraEnv) = nullptr;
|
||
if (state.debugRepl && evalSettings.ignoreExceptionsDuringTry)
|
||
{
|
||
/* to prevent starting the repl from exceptions withing a tryEval, null it. */
|
||
savedDebugRepl = state.debugRepl;
|
||
state.debugRepl = nullptr;
|
||
}
|
||
|
||
try {
|
||
state.forceValue(*args[0], pos);
|
||
attrs.insert(state.sValue, args[0]);
|
||
attrs.alloc("success").mkBool(true);
|
||
} catch (AssertionError & e) {
|
||
attrs.alloc(state.sValue).mkBool(false);
|
||
attrs.alloc("success").mkBool(false);
|
||
}
|
||
|
||
// restore the debugRepl pointer if we saved it earlier.
|
||
if (savedDebugRepl)
|
||
state.debugRepl = savedDebugRepl;
|
||
|
||
v.mkAttrs(attrs);
|
||
}
|
||
|
||
static RegisterPrimOp primop_tryEval({
|
||
.name = "__tryEval",
|
||
.args = {"e"},
|
||
.doc = R"(
|
||
Try to shallowly evaluate *e*. Return a set containing the
|
||
attributes `success` (`true` if *e* evaluated successfully,
|
||
`false` if an error was thrown) and `value`, equalling *e* if
|
||
successful and `false` otherwise. `tryEval` will only prevent
|
||
errors created by `throw` or `assert` from being thrown.
|
||
Errors `tryEval` will not catch are for example those created
|
||
by `abort` and type errors generated by builtins. Also note that
|
||
this doesn't evaluate *e* deeply, so `let e = { x = throw ""; };
|
||
in (builtins.tryEval e).success` will be `true`. Using
|
||
`builtins.deepSeq` one can get the expected result:
|
||
`let e = { x = throw ""; }; in
|
||
(builtins.tryEval (builtins.deepSeq e e)).success` will be
|
||
`false`.
|
||
)",
|
||
.fun = prim_tryEval,
|
||
});
|
||
|
||
/* Return an environment variable. Use with care. */
|
||
static void prim_getEnv(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
std::string name(state.forceStringNoCtx(*args[0], pos, "while evaluating the first argument passed to builtins.getEnv"));
|
||
v.mkString(evalSettings.restrictEval || evalSettings.pureEval ? "" : getEnv(name).value_or(""));
|
||
}
|
||
|
||
static RegisterPrimOp primop_getEnv({
|
||
.name = "__getEnv",
|
||
.args = {"s"},
|
||
.doc = R"(
|
||
`getEnv` returns the value of the environment variable *s*, or an
|
||
empty string if the variable doesn’t exist. This function should be
|
||
used with care, as it can introduce all sorts of nasty environment
|
||
dependencies in your Nix expression.
|
||
|
||
`getEnv` is used in Nix Packages to locate the file
|
||
`~/.nixpkgs/config.nix`, which contains user-local settings for Nix
|
||
Packages. (That is, it does a `getEnv "HOME"` to locate the user’s
|
||
home directory.)
|
||
)",
|
||
.fun = prim_getEnv,
|
||
});
|
||
|
||
/* Evaluate the first argument, then return the second argument. */
|
||
static void prim_seq(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceValue(*args[0], pos);
|
||
state.forceValue(*args[1], pos);
|
||
v = *args[1];
|
||
}
|
||
|
||
static RegisterPrimOp primop_seq({
|
||
.name = "__seq",
|
||
.args = {"e1", "e2"},
|
||
.doc = R"(
|
||
Evaluate *e1*, then evaluate and return *e2*. This ensures that a
|
||
computation is strict in the value of *e1*.
|
||
)",
|
||
.fun = prim_seq,
|
||
});
|
||
|
||
/* Evaluate the first argument deeply (i.e. recursing into lists and
|
||
attrsets), then return the second argument. */
|
||
static void prim_deepSeq(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceValueDeep(*args[0]);
|
||
state.forceValue(*args[1], pos);
|
||
v = *args[1];
|
||
}
|
||
|
||
static RegisterPrimOp primop_deepSeq({
|
||
.name = "__deepSeq",
|
||
.args = {"e1", "e2"},
|
||
.doc = R"(
|
||
This is like `seq e1 e2`, except that *e1* is evaluated *deeply*:
|
||
if it’s a list or set, its elements or attributes are also
|
||
evaluated recursively.
|
||
)",
|
||
.fun = prim_deepSeq,
|
||
});
|
||
|
||
/* Evaluate the first expression and print it on standard error. Then
|
||
return the second expression. Useful for debugging. */
|
||
static void prim_trace(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceValue(*args[0], pos);
|
||
if (args[0]->type() == nString)
|
||
printError("trace: %1%", args[0]->string_view());
|
||
else
|
||
printError("trace: %1%", ValuePrinter(state, *args[0]));
|
||
state.forceValue(*args[1], pos);
|
||
v = *args[1];
|
||
}
|
||
|
||
static RegisterPrimOp primop_trace({
|
||
.name = "__trace",
|
||
.args = {"e1", "e2"},
|
||
.doc = R"(
|
||
Evaluate *e1* and print its abstract syntax representation on
|
||
standard error. Then return *e2*. This function is useful for
|
||
debugging.
|
||
)",
|
||
.fun = prim_trace,
|
||
});
|
||
|
||
|
||
/* Takes two arguments and evaluates to the second one. Used as the
|
||
* builtins.traceVerbose implementation when --trace-verbose is not enabled
|
||
*/
|
||
static void prim_second(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceValue(*args[1], pos);
|
||
v = *args[1];
|
||
}
|
||
|
||
/*************************************************************
|
||
* Derivations
|
||
*************************************************************/
|
||
|
||
static void derivationStrictInternal(EvalState & state, const std::string & name, Bindings * attrs, Value & v);
|
||
|
||
/* Construct (as a unobservable side effect) a Nix derivation
|
||
expression that performs the derivation described by the argument
|
||
set. Returns the original set extended with the following
|
||
attributes: `outPath' containing the primary output path of the
|
||
derivation; `drvPath' containing the path of the Nix expression;
|
||
and `type' set to `derivation' to indicate that this is a
|
||
derivation. */
|
||
static void prim_derivationStrict(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceAttrs(*args[0], pos, "while evaluating the argument passed to builtins.derivationStrict");
|
||
|
||
Bindings * attrs = args[0]->attrs;
|
||
|
||
/* Figure out the name first (for stack backtraces). */
|
||
Bindings::iterator nameAttr = getAttr(state, state.sName, attrs, "in the attrset passed as argument to builtins.derivationStrict");
|
||
|
||
std::string drvName;
|
||
try {
|
||
drvName = state.forceStringNoCtx(*nameAttr->value, pos, "while evaluating the `name` attribute passed to builtins.derivationStrict");
|
||
} catch (Error & e) {
|
||
e.addTrace(state.positions[nameAttr->pos], "while evaluating the derivation attribute 'name'");
|
||
throw;
|
||
}
|
||
|
||
try {
|
||
derivationStrictInternal(state, drvName, attrs, v);
|
||
} catch (Error & e) {
|
||
Pos pos = state.positions[nameAttr->pos];
|
||
/*
|
||
* Here we make two abuses of the error system
|
||
*
|
||
* 1. We print the location as a string to avoid a code snippet being
|
||
* printed. While the location of the name attribute is a good hint, the
|
||
* exact code there is irrelevant.
|
||
*
|
||
* 2. We mark this trace as a frame trace, meaning that we stop printing
|
||
* less important traces from now on. In particular, this prevents the
|
||
* display of the automatic "while calling builtins.derivationStrict"
|
||
* trace, which is of little use for the public we target here.
|
||
*
|
||
* Please keep in mind that error reporting is done on a best-effort
|
||
* basis in nix. There is no accurate location for a derivation, as it
|
||
* often results from the composition of several functions
|
||
* (derivationStrict, derivation, mkDerivation, mkPythonModule, etc.)
|
||
*/
|
||
e.addTrace(nullptr, hintfmt(
|
||
"while evaluating derivation '%s'\n"
|
||
" whose name attribute is located at %s",
|
||
drvName, pos), true);
|
||
throw;
|
||
}
|
||
}
|
||
|
||
static void derivationStrictInternal(EvalState & state, const std::string &
|
||
drvName, Bindings * attrs, Value & v)
|
||
{
|
||
/* Check whether attributes should be passed as a JSON file. */
|
||
using nlohmann::json;
|
||
std::optional<json> jsonObject;
|
||
auto attr = attrs->find(state.sStructuredAttrs);
|
||
if (attr != attrs->end() &&
|
||
state.forceBool(*attr->value, noPos,
|
||
"while evaluating the `__structuredAttrs` "
|
||
"attribute passed to builtins.derivationStrict"))
|
||
jsonObject = json::object();
|
||
|
||
/* Check whether null attributes should be ignored. */
|
||
bool ignoreNulls = false;
|
||
attr = attrs->find(state.sIgnoreNulls);
|
||
if (attr != attrs->end())
|
||
ignoreNulls = state.forceBool(*attr->value, noPos, "while evaluating the `__ignoreNulls` attribute " "passed to builtins.derivationStrict");
|
||
|
||
/* Build the derivation expression by processing the attributes. */
|
||
Derivation drv;
|
||
drv.name = drvName;
|
||
|
||
NixStringContext context;
|
||
|
||
bool contentAddressed = false;
|
||
bool isImpure = false;
|
||
std::optional<std::string> outputHash;
|
||
std::string outputHashAlgo;
|
||
std::optional<ContentAddressMethod> ingestionMethod;
|
||
|
||
StringSet outputs;
|
||
outputs.insert("out");
|
||
|
||
for (auto & i : attrs->lexicographicOrder(state.symbols)) {
|
||
if (i->name == state.sIgnoreNulls) continue;
|
||
const std::string & key = state.symbols[i->name];
|
||
vomit("processing attribute '%1%'", key);
|
||
|
||
auto handleHashMode = [&](const std::string_view s) {
|
||
if (s == "recursive") ingestionMethod = FileIngestionMethod::Recursive;
|
||
else if (s == "flat") ingestionMethod = FileIngestionMethod::Flat;
|
||
else if (s == "text") {
|
||
experimentalFeatureSettings.require(Xp::DynamicDerivations);
|
||
ingestionMethod = TextIngestionMethod {};
|
||
} else
|
||
state.debugThrowLastTrace(EvalError({
|
||
.msg = hintfmt("invalid value '%s' for 'outputHashMode' attribute", s),
|
||
.errPos = state.positions[noPos]
|
||
}));
|
||
};
|
||
|
||
auto handleOutputs = [&](const Strings & ss) {
|
||
outputs.clear();
|
||
for (auto & j : ss) {
|
||
if (outputs.find(j) != outputs.end())
|
||
state.debugThrowLastTrace(EvalError({
|
||
.msg = hintfmt("duplicate derivation output '%1%'", j),
|
||
.errPos = state.positions[noPos]
|
||
}));
|
||
/* !!! Check whether j is a valid attribute
|
||
name. */
|
||
/* Derivations cannot be named ‘drv’, because
|
||
then we'd have an attribute ‘drvPath’ in
|
||
the resulting set. */
|
||
if (j == "drv")
|
||
state.debugThrowLastTrace(EvalError({
|
||
.msg = hintfmt("invalid derivation output name 'drv'" ),
|
||
.errPos = state.positions[noPos]
|
||
}));
|
||
outputs.insert(j);
|
||
}
|
||
if (outputs.empty())
|
||
state.debugThrowLastTrace(EvalError({
|
||
.msg = hintfmt("derivation cannot have an empty set of outputs"),
|
||
.errPos = state.positions[noPos]
|
||
}));
|
||
};
|
||
|
||
try {
|
||
// This try-catch block adds context for most errors.
|
||
// Use this empty error context to signify that we defer to it.
|
||
const std::string_view context_below("");
|
||
|
||
if (ignoreNulls) {
|
||
state.forceValue(*i->value, noPos);
|
||
if (i->value->type() == nNull) continue;
|
||
}
|
||
|
||
if (i->name == state.sContentAddressed && state.forceBool(*i->value, noPos, context_below)) {
|
||
contentAddressed = true;
|
||
experimentalFeatureSettings.require(Xp::CaDerivations);
|
||
}
|
||
|
||
else if (i->name == state.sImpure && state.forceBool(*i->value, noPos, context_below)) {
|
||
isImpure = true;
|
||
experimentalFeatureSettings.require(Xp::ImpureDerivations);
|
||
}
|
||
|
||
/* The `args' attribute is special: it supplies the
|
||
command-line arguments to the builder. */
|
||
else if (i->name == state.sArgs) {
|
||
state.forceList(*i->value, noPos, context_below);
|
||
for (auto elem : i->value->listItems()) {
|
||
auto s = state.coerceToString(noPos, *elem, context,
|
||
"while evaluating an element of the argument list",
|
||
true).toOwned();
|
||
drv.args.push_back(s);
|
||
}
|
||
}
|
||
|
||
/* All other attributes are passed to the builder through
|
||
the environment. */
|
||
else {
|
||
|
||
if (jsonObject) {
|
||
|
||
if (i->name == state.sStructuredAttrs) continue;
|
||
|
||
(*jsonObject)[key] = printValueAsJSON(state, true, *i->value, noPos, context);
|
||
|
||
if (i->name == state.sBuilder)
|
||
drv.builder = state.forceString(*i->value, context, noPos, context_below);
|
||
else if (i->name == state.sSystem)
|
||
drv.platform = state.forceStringNoCtx(*i->value, noPos, context_below);
|
||
else if (i->name == state.sOutputHash)
|
||
outputHash = state.forceStringNoCtx(*i->value, noPos, context_below);
|
||
else if (i->name == state.sOutputHashAlgo)
|
||
outputHashAlgo = state.forceStringNoCtx(*i->value, noPos, context_below);
|
||
else if (i->name == state.sOutputHashMode)
|
||
handleHashMode(state.forceStringNoCtx(*i->value, noPos, context_below));
|
||
else if (i->name == state.sOutputs) {
|
||
/* Require ‘outputs’ to be a list of strings. */
|
||
state.forceList(*i->value, noPos, context_below);
|
||
Strings ss;
|
||
for (auto elem : i->value->listItems())
|
||
ss.emplace_back(state.forceStringNoCtx(*elem, noPos, context_below));
|
||
handleOutputs(ss);
|
||
}
|
||
|
||
} else {
|
||
auto s = state.coerceToString(noPos, *i->value, context, context_below, true).toOwned();
|
||
drv.env.emplace(key, s);
|
||
if (i->name == state.sBuilder) drv.builder = std::move(s);
|
||
else if (i->name == state.sSystem) drv.platform = std::move(s);
|
||
else if (i->name == state.sOutputHash) outputHash = std::move(s);
|
||
else if (i->name == state.sOutputHashAlgo) outputHashAlgo = std::move(s);
|
||
else if (i->name == state.sOutputHashMode) handleHashMode(s);
|
||
else if (i->name == state.sOutputs)
|
||
handleOutputs(tokenizeString<Strings>(s));
|
||
}
|
||
|
||
}
|
||
|
||
} catch (Error & e) {
|
||
e.addTrace(state.positions[i->pos],
|
||
hintfmt("while evaluating attribute '%1%' of derivation '%2%'", key, drvName),
|
||
true);
|
||
throw;
|
||
}
|
||
}
|
||
|
||
if (jsonObject) {
|
||
drv.env.emplace("__json", jsonObject->dump());
|
||
jsonObject.reset();
|
||
}
|
||
|
||
/* Everything in the context of the strings in the derivation
|
||
attributes should be added as dependencies of the resulting
|
||
derivation. */
|
||
for (auto & c : context) {
|
||
std::visit(overloaded {
|
||
/* Since this allows the builder to gain access to every
|
||
path in the dependency graph of the derivation (including
|
||
all outputs), all paths in the graph must be added to
|
||
this derivation's list of inputs to ensure that they are
|
||
available when the builder runs. */
|
||
[&](const NixStringContextElem::DrvDeep & d) {
|
||
/* !!! This doesn't work if readOnlyMode is set. */
|
||
StorePathSet refs;
|
||
state.store->computeFSClosure(d.drvPath, refs);
|
||
for (auto & j : refs) {
|
||
drv.inputSrcs.insert(j);
|
||
if (j.isDerivation()) {
|
||
drv.inputDrvs.map[j].value = state.store->readDerivation(j).outputNames();
|
||
}
|
||
}
|
||
},
|
||
[&](const NixStringContextElem::Built & b) {
|
||
drv.inputDrvs.ensureSlot(*b.drvPath).value.insert(b.output);
|
||
},
|
||
[&](const NixStringContextElem::Opaque & o) {
|
||
drv.inputSrcs.insert(o.path);
|
||
},
|
||
}, c.raw);
|
||
}
|
||
|
||
/* Do we have all required attributes? */
|
||
if (drv.builder == "")
|
||
state.debugThrowLastTrace(EvalError({
|
||
.msg = hintfmt("required attribute 'builder' missing"),
|
||
.errPos = state.positions[noPos]
|
||
}));
|
||
|
||
if (drv.platform == "")
|
||
state.debugThrowLastTrace(EvalError({
|
||
.msg = hintfmt("required attribute 'system' missing"),
|
||
.errPos = state.positions[noPos]
|
||
}));
|
||
|
||
/* Check whether the derivation name is valid. */
|
||
if (isDerivation(drvName) &&
|
||
!(ingestionMethod == ContentAddressMethod { TextIngestionMethod { } } &&
|
||
outputs.size() == 1 &&
|
||
*(outputs.begin()) == "out"))
|
||
{
|
||
state.debugThrowLastTrace(EvalError({
|
||
.msg = hintfmt("derivation names are allowed to end in '%s' only if they produce a single derivation file", drvExtension),
|
||
.errPos = state.positions[noPos]
|
||
}));
|
||
}
|
||
|
||
if (outputHash) {
|
||
/* Handle fixed-output derivations.
|
||
|
||
Ignore `__contentAddressed` because fixed output derivations are
|
||
already content addressed. */
|
||
if (outputs.size() != 1 || *(outputs.begin()) != "out")
|
||
state.debugThrowLastTrace(Error({
|
||
.msg = hintfmt("multiple outputs are not supported in fixed-output derivations"),
|
||
.errPos = state.positions[noPos]
|
||
}));
|
||
|
||
auto h = newHashAllowEmpty(*outputHash, parseHashAlgoOpt(outputHashAlgo));
|
||
|
||
auto method = ingestionMethod.value_or(FileIngestionMethod::Flat);
|
||
|
||
DerivationOutput::CAFixed dof {
|
||
.ca = ContentAddress {
|
||
.method = std::move(method),
|
||
.hash = std::move(h),
|
||
},
|
||
};
|
||
|
||
drv.env["out"] = state.store->printStorePath(dof.path(*state.store, drvName, "out"));
|
||
drv.outputs.insert_or_assign("out", std::move(dof));
|
||
}
|
||
|
||
else if (contentAddressed || isImpure) {
|
||
if (contentAddressed && isImpure)
|
||
throw EvalError({
|
||
.msg = hintfmt("derivation cannot be both content-addressed and impure"),
|
||
.errPos = state.positions[noPos]
|
||
});
|
||
|
||
auto ha = parseHashAlgoOpt(outputHashAlgo).value_or(HashAlgorithm::SHA256);
|
||
auto method = ingestionMethod.value_or(FileIngestionMethod::Recursive);
|
||
|
||
for (auto & i : outputs) {
|
||
drv.env[i] = hashPlaceholder(i);
|
||
if (isImpure)
|
||
drv.outputs.insert_or_assign(i,
|
||
DerivationOutput::Impure {
|
||
.method = method,
|
||
.hashAlgo = ha,
|
||
});
|
||
else
|
||
drv.outputs.insert_or_assign(i,
|
||
DerivationOutput::CAFloating {
|
||
.method = method,
|
||
.hashAlgo = ha,
|
||
});
|
||
}
|
||
}
|
||
|
||
else {
|
||
/* Compute a hash over the "masked" store derivation, which is
|
||
the final one except that in the list of outputs, the
|
||
output paths are empty strings, and the corresponding
|
||
environment variables have an empty value. This ensures
|
||
that changes in the set of output names do get reflected in
|
||
the hash. */
|
||
for (auto & i : outputs) {
|
||
drv.env[i] = "";
|
||
drv.outputs.insert_or_assign(i,
|
||
DerivationOutput::Deferred { });
|
||
}
|
||
|
||
auto hashModulo = hashDerivationModulo(*state.store, Derivation(drv), true);
|
||
switch (hashModulo.kind) {
|
||
case DrvHash::Kind::Regular:
|
||
for (auto & i : outputs) {
|
||
auto h = get(hashModulo.hashes, i);
|
||
if (!h)
|
||
throw AssertionError({
|
||
.msg = hintfmt("derivation produced no hash for output '%s'", i),
|
||
.errPos = state.positions[noPos],
|
||
});
|
||
auto outPath = state.store->makeOutputPath(i, *h, drvName);
|
||
drv.env[i] = state.store->printStorePath(outPath);
|
||
drv.outputs.insert_or_assign(
|
||
i,
|
||
DerivationOutput::InputAddressed {
|
||
.path = std::move(outPath),
|
||
});
|
||
}
|
||
break;
|
||
;
|
||
case DrvHash::Kind::Deferred:
|
||
for (auto & i : outputs) {
|
||
drv.outputs.insert_or_assign(i, DerivationOutput::Deferred {});
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Write the resulting term into the Nix store directory. */
|
||
auto drvPath = writeDerivation(*state.store, drv, state.repair);
|
||
auto drvPathS = state.store->printStorePath(drvPath);
|
||
|
||
printMsg(lvlChatty, "instantiated '%1%' -> '%2%'", drvName, drvPathS);
|
||
|
||
/* Optimisation, but required in read-only mode! because in that
|
||
case we don't actually write store derivations, so we can't
|
||
read them later. */
|
||
{
|
||
auto h = hashDerivationModulo(*state.store, drv, false);
|
||
drvHashes.lock()->insert_or_assign(drvPath, h);
|
||
}
|
||
|
||
auto result = state.buildBindings(1 + drv.outputs.size());
|
||
result.alloc(state.sDrvPath).mkString(drvPathS, {
|
||
NixStringContextElem::DrvDeep { .drvPath = drvPath },
|
||
});
|
||
for (auto & i : drv.outputs)
|
||
mkOutputString(state, result, drvPath, i);
|
||
|
||
v.mkAttrs(result);
|
||
}
|
||
|
||
static RegisterPrimOp primop_derivationStrict(PrimOp {
|
||
.name = "derivationStrict",
|
||
.arity = 1,
|
||
.fun = prim_derivationStrict,
|
||
});
|
||
|
||
/* Return a placeholder string for the specified output that will be
|
||
substituted by the corresponding output path at build time. For
|
||
example, 'placeholder "out"' returns the string
|
||
/1rz4g4znpzjwh1xymhjpm42vipw92pr73vdgl6xs1hycac8kf2n9. At build
|
||
time, any occurrence of this string in an derivation attribute will
|
||
be replaced with the concrete path in the Nix store of the output
|
||
‘out’. */
|
||
static void prim_placeholder(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
v.mkString(hashPlaceholder(state.forceStringNoCtx(*args[0], pos, "while evaluating the first argument passed to builtins.placeholder")));
|
||
}
|
||
|
||
static RegisterPrimOp primop_placeholder({
|
||
.name = "placeholder",
|
||
.args = {"output"},
|
||
.doc = R"(
|
||
Return a placeholder string for the specified *output* that will be
|
||
substituted by the corresponding output path at build time. Typical
|
||
outputs would be `"out"`, `"bin"` or `"dev"`.
|
||
)",
|
||
.fun = prim_placeholder,
|
||
});
|
||
|
||
|
||
/*************************************************************
|
||
* Paths
|
||
*************************************************************/
|
||
|
||
|
||
/* Convert the argument to a path. !!! obsolete? */
|
||
static void prim_toPath(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
NixStringContext context;
|
||
auto path = state.coerceToPath(pos, *args[0], context, "while evaluating the first argument passed to builtins.toPath");
|
||
v.mkString(path.path.abs(), context);
|
||
}
|
||
|
||
static RegisterPrimOp primop_toPath({
|
||
.name = "__toPath",
|
||
.args = {"s"},
|
||
.doc = R"(
|
||
**DEPRECATED.** Use `/. + "/path"` to convert a string into an absolute
|
||
path. For relative paths, use `./. + "/path"`.
|
||
)",
|
||
.fun = prim_toPath,
|
||
});
|
||
|
||
/* Allow a valid store path to be used in an expression. This is
|
||
useful in some generated expressions such as in nix-push, which
|
||
generates a call to a function with an already existing store path
|
||
as argument. You don't want to use `toPath' here because it copies
|
||
the path to the Nix store, which yields a copy like
|
||
/nix/store/newhash-oldhash-oldname. In the past, `toPath' had
|
||
special case behaviour for store paths, but that created weird
|
||
corner cases. */
|
||
static void prim_storePath(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
if (evalSettings.pureEval)
|
||
state.debugThrowLastTrace(EvalError({
|
||
.msg = hintfmt("'%s' is not allowed in pure evaluation mode", "builtins.storePath"),
|
||
.errPos = state.positions[pos]
|
||
}));
|
||
|
||
NixStringContext context;
|
||
auto path = state.coerceToPath(pos, *args[0], context, "while evaluating the first argument passed to 'builtins.storePath'").path;
|
||
/* Resolve symlinks in ‘path’, unless ‘path’ itself is a symlink
|
||
directly in the store. The latter condition is necessary so
|
||
e.g. nix-push does the right thing. */
|
||
if (!state.store->isStorePath(path.abs()))
|
||
path = CanonPath(canonPath(path.abs(), true));
|
||
if (!state.store->isInStore(path.abs()))
|
||
state.debugThrowLastTrace(EvalError({
|
||
.msg = hintfmt("path '%1%' is not in the Nix store", path),
|
||
.errPos = state.positions[pos]
|
||
}));
|
||
auto path2 = state.store->toStorePath(path.abs()).first;
|
||
if (!settings.readOnlyMode)
|
||
state.store->ensurePath(path2);
|
||
context.insert(NixStringContextElem::Opaque { .path = path2 });
|
||
v.mkString(path.abs(), context);
|
||
}
|
||
|
||
static RegisterPrimOp primop_storePath({
|
||
.name = "__storePath",
|
||
.args = {"path"},
|
||
.doc = R"(
|
||
This function allows you to define a dependency on an already
|
||
existing store path. For example, the derivation attribute `src
|
||
= builtins.storePath /nix/store/f1d18v1y…-source` causes the
|
||
derivation to depend on the specified path, which must exist or
|
||
be substitutable. Note that this differs from a plain path
|
||
(e.g. `src = /nix/store/f1d18v1y…-source`) in that the latter
|
||
causes the path to be *copied* again to the Nix store, resulting
|
||
in a new path (e.g. `/nix/store/ld01dnzc…-source-source`).
|
||
|
||
Not available in [pure evaluation mode](@docroot@/command-ref/conf-file.md#conf-pure-eval).
|
||
|
||
See also [`builtins.fetchClosure`](#builtins-fetchClosure).
|
||
)",
|
||
.fun = prim_storePath,
|
||
});
|
||
|
||
static void prim_pathExists(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
try {
|
||
auto & arg = *args[0];
|
||
|
||
auto path = realisePath(state, pos, arg);
|
||
|
||
/* SourcePath doesn't know about trailing slash. */
|
||
auto mustBeDir = arg.type() == nString
|
||
&& (arg.string_view().ends_with("/")
|
||
|| arg.string_view().ends_with("/."));
|
||
|
||
auto st = path.maybeLstat();
|
||
auto exists = st && (!mustBeDir || st->type == SourceAccessor::tDirectory);
|
||
v.mkBool(exists);
|
||
} catch (RestrictedPathError & e) {
|
||
v.mkBool(false);
|
||
}
|
||
}
|
||
|
||
static RegisterPrimOp primop_pathExists({
|
||
.name = "__pathExists",
|
||
.args = {"path"},
|
||
.doc = R"(
|
||
Return `true` if the path *path* exists at evaluation time, and
|
||
`false` otherwise.
|
||
)",
|
||
.fun = prim_pathExists,
|
||
});
|
||
|
||
/* Return the base name of the given string, i.e., everything
|
||
following the last slash. */
|
||
static void prim_baseNameOf(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
NixStringContext context;
|
||
v.mkString(baseNameOf(*state.coerceToString(pos, *args[0], context,
|
||
"while evaluating the first argument passed to builtins.baseNameOf",
|
||
false, false)), context);
|
||
}
|
||
|
||
static RegisterPrimOp primop_baseNameOf({
|
||
.name = "baseNameOf",
|
||
.args = {"s"},
|
||
.doc = R"(
|
||
Return the *base name* of the string *s*, that is, everything
|
||
following the final slash in the string. This is similar to the GNU
|
||
`basename` command.
|
||
)",
|
||
.fun = prim_baseNameOf,
|
||
});
|
||
|
||
/* Return the directory of the given path, i.e., everything before the
|
||
last slash. Return either a path or a string depending on the type
|
||
of the argument. */
|
||
static void prim_dirOf(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceValue(*args[0], pos);
|
||
if (args[0]->type() == nPath) {
|
||
auto path = args[0]->path();
|
||
v.mkPath(path.path.isRoot() ? path : path.parent());
|
||
} else {
|
||
NixStringContext context;
|
||
auto path = state.coerceToString(pos, *args[0], context,
|
||
"while evaluating the first argument passed to 'builtins.dirOf'",
|
||
false, false);
|
||
auto dir = dirOf(*path);
|
||
v.mkString(dir, context);
|
||
}
|
||
}
|
||
|
||
static RegisterPrimOp primop_dirOf({
|
||
.name = "dirOf",
|
||
.args = {"s"},
|
||
.doc = R"(
|
||
Return the directory part of the string *s*, that is, everything
|
||
before the final slash in the string. This is similar to the GNU
|
||
`dirname` command.
|
||
)",
|
||
.fun = prim_dirOf,
|
||
});
|
||
|
||
/* Return the contents of a file as a string. */
|
||
static void prim_readFile(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
auto path = realisePath(state, pos, *args[0]);
|
||
auto s = path.readFile();
|
||
if (s.find((char) 0) != std::string::npos)
|
||
state.debugThrowLastTrace(Error("the contents of the file '%1%' cannot be represented as a Nix string", path));
|
||
StorePathSet refs;
|
||
if (state.store->isInStore(path.path.abs())) {
|
||
try {
|
||
refs = state.store->queryPathInfo(state.store->toStorePath(path.path.abs()).first)->references;
|
||
} catch (Error &) { // FIXME: should be InvalidPathError
|
||
}
|
||
// Re-scan references to filter down to just the ones that actually occur in the file.
|
||
auto refsSink = PathRefScanSink::fromPaths(refs);
|
||
refsSink << s;
|
||
refs = refsSink.getResultPaths();
|
||
}
|
||
NixStringContext context;
|
||
for (auto && p : std::move(refs)) {
|
||
context.insert(NixStringContextElem::Opaque {
|
||
.path = std::move((StorePath &&)p),
|
||
});
|
||
}
|
||
v.mkString(s, context);
|
||
}
|
||
|
||
static RegisterPrimOp primop_readFile({
|
||
.name = "__readFile",
|
||
.args = {"path"},
|
||
.doc = R"(
|
||
Return the contents of the file *path* as a string.
|
||
)",
|
||
.fun = prim_readFile,
|
||
});
|
||
|
||
/* Find a file in the Nix search path. Used to implement <x> paths,
|
||
which are desugared to 'findFile __nixPath "x"'. */
|
||
static void prim_findFile(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceList(*args[0], pos, "while evaluating the first argument passed to builtins.findFile");
|
||
|
||
SearchPath searchPath;
|
||
|
||
for (auto v2 : args[0]->listItems()) {
|
||
state.forceAttrs(*v2, pos, "while evaluating an element of the list passed to builtins.findFile");
|
||
|
||
std::string prefix;
|
||
Bindings::iterator i = v2->attrs->find(state.sPrefix);
|
||
if (i != v2->attrs->end())
|
||
prefix = state.forceStringNoCtx(*i->value, pos, "while evaluating the `prefix` attribute of an element of the list passed to builtins.findFile");
|
||
|
||
i = getAttr(state, state.sPath, v2->attrs, "in an element of the __nixPath");
|
||
|
||
NixStringContext context;
|
||
auto path = state.coerceToString(pos, *i->value, context,
|
||
"while evaluating the `path` attribute of an element of the list passed to builtins.findFile",
|
||
false, false).toOwned();
|
||
|
||
try {
|
||
auto rewrites = state.realiseContext(context);
|
||
path = rewriteStrings(path, rewrites);
|
||
} catch (InvalidPathError & e) {
|
||
state.debugThrowLastTrace(EvalError({
|
||
.msg = hintfmt("cannot find '%1%', since path '%2%' is not valid", path, e.path),
|
||
.errPos = state.positions[pos]
|
||
}));
|
||
}
|
||
|
||
searchPath.elements.emplace_back(SearchPath::Elem {
|
||
.prefix = SearchPath::Prefix { .s = prefix },
|
||
.path = SearchPath::Path { .s = path },
|
||
});
|
||
}
|
||
|
||
auto path = state.forceStringNoCtx(*args[1], pos, "while evaluating the second argument passed to builtins.findFile");
|
||
|
||
v.mkPath(state.findFile(searchPath, path, pos));
|
||
}
|
||
|
||
static RegisterPrimOp primop_findFile(PrimOp {
|
||
.name = "__findFile",
|
||
.args = {"search-path", "lookup-path"},
|
||
.doc = R"(
|
||
Find *lookup-path* in *search-path*.
|
||
|
||
A search path is represented list of [attribute sets](./values.md#attribute-set) with two attributes:
|
||
- `prefix` is a relative path.
|
||
- `path` denotes a file system location
|
||
The exact syntax depends on the command line interface.
|
||
|
||
Examples of search path attribute sets:
|
||
|
||
- ```
|
||
{
|
||
prefix = "nixos-config";
|
||
path = "/etc/nixos/configuration.nix";
|
||
}
|
||
```
|
||
|
||
- ```
|
||
{
|
||
prefix = "";
|
||
path = "/nix/var/nix/profiles/per-user/root/channels";
|
||
}
|
||
```
|
||
|
||
The lookup algorithm checks each entry until a match is found, returning a [path value](@docroot@/language/values.html#type-path) of the match:
|
||
|
||
- If *lookup-path* matches `prefix`, then the remainder of *lookup-path* (the "suffix") is searched for within the directory denoted by `path`.
|
||
Note that the `path` may need to be downloaded at this point to look inside.
|
||
- If the suffix is found inside that directory, then the entry is a match.
|
||
The combined absolute path of the directory (now downloaded if need be) and the suffix is returned.
|
||
|
||
[Lookup path](@docroot@/language/constructs/lookup-path.md) expressions can be [desugared](https://en.wikipedia.org/wiki/Syntactic_sugar) using this and [`builtins.nixPath`](@docroot@/language/builtin-constants.md#builtins-nixPath):
|
||
|
||
```nix
|
||
<nixpkgs>
|
||
```
|
||
|
||
is equivalent to:
|
||
|
||
```nix
|
||
builtins.findFile builtins.nixPath "nixpkgs"
|
||
```
|
||
)",
|
||
.fun = prim_findFile,
|
||
});
|
||
|
||
/* Return the cryptographic hash of a file in base-16. */
|
||
static void prim_hashFile(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
auto algo = state.forceStringNoCtx(*args[0], pos, "while evaluating the first argument passed to builtins.hashFile");
|
||
std::optional<HashAlgorithm> ha = parseHashAlgo(algo);
|
||
if (!ha)
|
||
state.debugThrowLastTrace(Error({
|
||
.msg = hintfmt("unknown hash algo '%1%'", algo),
|
||
.errPos = state.positions[pos]
|
||
}));
|
||
|
||
auto path = realisePath(state, pos, *args[1]);
|
||
|
||
v.mkString(hashString(*ha, path.readFile()).to_string(HashFormat::Base16, false));
|
||
}
|
||
|
||
static RegisterPrimOp primop_hashFile({
|
||
.name = "__hashFile",
|
||
.args = {"type", "p"},
|
||
.doc = R"(
|
||
Return a base-16 representation of the cryptographic hash of the
|
||
file at path *p*. The hash algorithm specified by *type* must be one
|
||
of `"md5"`, `"sha1"`, `"sha256"` or `"sha512"`.
|
||
)",
|
||
.fun = prim_hashFile,
|
||
});
|
||
|
||
static std::string_view fileTypeToString(InputAccessor::Type type)
|
||
{
|
||
return
|
||
type == InputAccessor::Type::tRegular ? "regular" :
|
||
type == InputAccessor::Type::tDirectory ? "directory" :
|
||
type == InputAccessor::Type::tSymlink ? "symlink" :
|
||
"unknown";
|
||
}
|
||
|
||
static void prim_readFileType(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
auto path = realisePath(state, pos, *args[0], false);
|
||
/* Retrieve the directory entry type and stringize it. */
|
||
v.mkString(fileTypeToString(path.lstat().type));
|
||
}
|
||
|
||
static RegisterPrimOp primop_readFileType({
|
||
.name = "__readFileType",
|
||
.args = {"p"},
|
||
.doc = R"(
|
||
Determine the directory entry type of a filesystem node, being
|
||
one of "directory", "regular", "symlink", or "unknown".
|
||
)",
|
||
.fun = prim_readFileType,
|
||
});
|
||
|
||
/* Read a directory (without . or ..) */
|
||
static void prim_readDir(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
auto path = realisePath(state, pos, *args[0]);
|
||
|
||
// Retrieve directory entries for all nodes in a directory.
|
||
// This is similar to `getFileType` but is optimized to reduce system calls
|
||
// on many systems.
|
||
auto entries = path.readDirectory();
|
||
auto attrs = state.buildBindings(entries.size());
|
||
|
||
// If we hit unknown directory entry types we may need to fallback to
|
||
// using `getFileType` on some systems.
|
||
// In order to reduce system calls we make each lookup lazy by using
|
||
// `builtins.readFileType` application.
|
||
Value * readFileType = nullptr;
|
||
|
||
for (auto & [name, type] : entries) {
|
||
auto & attr = attrs.alloc(name);
|
||
if (!type) {
|
||
// Some filesystems or operating systems may not be able to return
|
||
// detailed node info quickly in this case we produce a thunk to
|
||
// query the file type lazily.
|
||
auto epath = state.allocValue();
|
||
epath->mkPath(path / name);
|
||
if (!readFileType)
|
||
readFileType = &state.getBuiltin("readFileType");
|
||
attr.mkApp(readFileType, epath);
|
||
} else {
|
||
// This branch of the conditional is much more likely.
|
||
// Here we just stringize the directory entry type.
|
||
attr.mkString(fileTypeToString(*type));
|
||
}
|
||
}
|
||
|
||
v.mkAttrs(attrs);
|
||
}
|
||
|
||
static RegisterPrimOp primop_readDir({
|
||
.name = "__readDir",
|
||
.args = {"path"},
|
||
.doc = R"(
|
||
Return the contents of the directory *path* as a set mapping
|
||
directory entries to the corresponding file type. For instance, if
|
||
directory `A` contains a regular file `B` and another directory
|
||
`C`, then `builtins.readDir ./A` will return the set
|
||
|
||
```nix
|
||
{ B = "regular"; C = "directory"; }
|
||
```
|
||
|
||
The possible values for the file type are `"regular"`,
|
||
`"directory"`, `"symlink"` and `"unknown"`.
|
||
)",
|
||
.fun = prim_readDir,
|
||
});
|
||
|
||
/* Extend single element string context with another output. */
|
||
static void prim_outputOf(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
SingleDerivedPath drvPath = state.coerceToSingleDerivedPath(pos, *args[0], "while evaluating the first argument to builtins.outputOf");
|
||
|
||
OutputNameView outputName = state.forceStringNoCtx(*args[1], pos, "while evaluating the second argument to builtins.outputOf");
|
||
|
||
state.mkSingleDerivedPathString(
|
||
SingleDerivedPath::Built {
|
||
.drvPath = make_ref<SingleDerivedPath>(drvPath),
|
||
.output = std::string { outputName },
|
||
},
|
||
v);
|
||
}
|
||
|
||
static RegisterPrimOp primop_outputOf({
|
||
.name = "__outputOf",
|
||
.args = {"derivation-reference", "output-name"},
|
||
.doc = R"(
|
||
Return the output path of a derivation, literally or using a placeholder if needed.
|
||
|
||
If the derivation has a statically-known output path (i.e. the derivation output is input-addressed, or fixed content-addresed), the output path will just be returned.
|
||
But if the derivation is content-addressed or if the derivation is itself not-statically produced (i.e. is the output of another derivation), a placeholder will be returned instead.
|
||
|
||
*`derivation reference`* must be a string that may contain a regular store path to a derivation, or may be a placeholder reference. If the derivation is produced by a derivation, you must explicitly select `drv.outPath`.
|
||
This primop can be chained arbitrarily deeply.
|
||
For instance,
|
||
```nix
|
||
builtins.outputOf
|
||
(builtins.outputOf myDrv "out")
|
||
"out"
|
||
```
|
||
will return a placeholder for the output of the output of `myDrv`.
|
||
|
||
This primop corresponds to the `^` sigil for derivable paths, e.g. as part of installable syntax on the command line.
|
||
)",
|
||
.fun = prim_outputOf,
|
||
.experimentalFeature = Xp::DynamicDerivations,
|
||
});
|
||
|
||
/*************************************************************
|
||
* Creating files
|
||
*************************************************************/
|
||
|
||
|
||
/* Convert the argument (which can be any Nix expression) to an XML
|
||
representation returned in a string. Not all Nix expressions can
|
||
be sensibly or completely represented (e.g., functions). */
|
||
static void prim_toXML(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
std::ostringstream out;
|
||
NixStringContext context;
|
||
printValueAsXML(state, true, false, *args[0], out, context, pos);
|
||
v.mkString(out.str(), context);
|
||
}
|
||
|
||
static RegisterPrimOp primop_toXML({
|
||
.name = "__toXML",
|
||
.args = {"e"},
|
||
.doc = R"(
|
||
Return a string containing an XML representation of *e*. The main
|
||
application for `toXML` is to communicate information with the
|
||
builder in a more structured format than plain environment
|
||
variables.
|
||
|
||
Here is an example where this is the case:
|
||
|
||
```nix
|
||
{ stdenv, fetchurl, libxslt, jira, uberwiki }:
|
||
|
||
stdenv.mkDerivation (rec {
|
||
name = "web-server";
|
||
|
||
buildInputs = [ libxslt ];
|
||
|
||
builder = builtins.toFile "builder.sh" "
|
||
source $stdenv/setup
|
||
mkdir $out
|
||
echo "$servlets" | xsltproc ${stylesheet} - > $out/server-conf.xml ①
|
||
";
|
||
|
||
stylesheet = builtins.toFile "stylesheet.xsl" ②
|
||
"<?xml version='1.0' encoding='UTF-8'?>
|
||
<xsl:stylesheet xmlns:xsl='http://www.w3.org/1999/XSL/Transform' version='1.0'>
|
||
<xsl:template match='/'>
|
||
<Configure>
|
||
<xsl:for-each select='/expr/list/attrs'>
|
||
<Call name='addWebApplication'>
|
||
<Arg><xsl:value-of select=\"attr[@name = 'path']/string/@value\" /></Arg>
|
||
<Arg><xsl:value-of select=\"attr[@name = 'war']/path/@value\" /></Arg>
|
||
</Call>
|
||
</xsl:for-each>
|
||
</Configure>
|
||
</xsl:template>
|
||
</xsl:stylesheet>
|
||
";
|
||
|
||
servlets = builtins.toXML [ ③
|
||
{ path = "/bugtracker"; war = jira + "/lib/atlassian-jira.war"; }
|
||
{ path = "/wiki"; war = uberwiki + "/uberwiki.war"; }
|
||
];
|
||
})
|
||
```
|
||
|
||
The builder is supposed to generate the configuration file for a
|
||
[Jetty servlet container](http://jetty.mortbay.org/). A servlet
|
||
container contains a number of servlets (`*.war` files) each
|
||
exported under a specific URI prefix. So the servlet configuration
|
||
is a list of sets containing the `path` and `war` of the servlet
|
||
(①). This kind of information is difficult to communicate with the
|
||
normal method of passing information through an environment
|
||
variable, which just concatenates everything together into a
|
||
string (which might just work in this case, but wouldn’t work if
|
||
fields are optional or contain lists themselves). Instead the Nix
|
||
expression is converted to an XML representation with `toXML`,
|
||
which is unambiguous and can easily be processed with the
|
||
appropriate tools. For instance, in the example an XSLT stylesheet
|
||
(at point ②) is applied to it (at point ①) to generate the XML
|
||
configuration file for the Jetty server. The XML representation
|
||
produced at point ③ by `toXML` is as follows:
|
||
|
||
```xml
|
||
<?xml version='1.0' encoding='utf-8'?>
|
||
<expr>
|
||
<list>
|
||
<attrs>
|
||
<attr name="path">
|
||
<string value="/bugtracker" />
|
||
</attr>
|
||
<attr name="war">
|
||
<path value="/nix/store/d1jh9pasa7k2...-jira/lib/atlassian-jira.war" />
|
||
</attr>
|
||
</attrs>
|
||
<attrs>
|
||
<attr name="path">
|
||
<string value="/wiki" />
|
||
</attr>
|
||
<attr name="war">
|
||
<path value="/nix/store/y6423b1yi4sx...-uberwiki/uberwiki.war" />
|
||
</attr>
|
||
</attrs>
|
||
</list>
|
||
</expr>
|
||
```
|
||
|
||
Note that we used the `toFile` built-in to write the builder and
|
||
the stylesheet “inline” in the Nix expression. The path of the
|
||
stylesheet is spliced into the builder using the syntax `xsltproc
|
||
${stylesheet}`.
|
||
)",
|
||
.fun = prim_toXML,
|
||
});
|
||
|
||
/* Convert the argument (which can be any Nix expression) to a JSON
|
||
string. Not all Nix expressions can be sensibly or completely
|
||
represented (e.g., functions). */
|
||
static void prim_toJSON(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
std::ostringstream out;
|
||
NixStringContext context;
|
||
printValueAsJSON(state, true, *args[0], pos, out, context);
|
||
v.mkString(out.str(), context);
|
||
}
|
||
|
||
static RegisterPrimOp primop_toJSON({
|
||
.name = "__toJSON",
|
||
.args = {"e"},
|
||
.doc = R"(
|
||
Return a string containing a JSON representation of *e*. Strings,
|
||
integers, floats, booleans, nulls and lists are mapped to their JSON
|
||
equivalents. Sets (except derivations) are represented as objects.
|
||
Derivations are translated to a JSON string containing the
|
||
derivation’s output path. Paths are copied to the store and
|
||
represented as a JSON string of the resulting store path.
|
||
)",
|
||
.fun = prim_toJSON,
|
||
});
|
||
|
||
/* Parse a JSON string to a value. */
|
||
static void prim_fromJSON(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
auto s = state.forceStringNoCtx(*args[0], pos, "while evaluating the first argument passed to builtins.fromJSON");
|
||
try {
|
||
parseJSON(state, s, v);
|
||
} catch (JSONParseError &e) {
|
||
e.addTrace(state.positions[pos], "while decoding a JSON string");
|
||
throw;
|
||
}
|
||
}
|
||
|
||
static RegisterPrimOp primop_fromJSON({
|
||
.name = "__fromJSON",
|
||
.args = {"e"},
|
||
.doc = R"(
|
||
Convert a JSON string to a Nix value. For example,
|
||
|
||
```nix
|
||
builtins.fromJSON ''{"x": [1, 2, 3], "y": null}''
|
||
```
|
||
|
||
returns the value `{ x = [ 1 2 3 ]; y = null; }`.
|
||
)",
|
||
.fun = prim_fromJSON,
|
||
});
|
||
|
||
/* Store a string in the Nix store as a source file that can be used
|
||
as an input by derivations. */
|
||
static void prim_toFile(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
NixStringContext context;
|
||
std::string name(state.forceStringNoCtx(*args[0], pos, "while evaluating the first argument passed to builtins.toFile"));
|
||
std::string contents(state.forceString(*args[1], context, pos, "while evaluating the second argument passed to builtins.toFile"));
|
||
|
||
StorePathSet refs;
|
||
|
||
for (auto c : context) {
|
||
if (auto p = std::get_if<NixStringContextElem::Opaque>(&c.raw))
|
||
refs.insert(p->path);
|
||
else
|
||
state.debugThrowLastTrace(EvalError({
|
||
.msg = hintfmt(
|
||
"in 'toFile': the file named '%1%' must not contain a reference "
|
||
"to a derivation but contains (%2%)",
|
||
name, c.to_string()),
|
||
.errPos = state.positions[pos]
|
||
}));
|
||
}
|
||
|
||
auto storePath = settings.readOnlyMode
|
||
? state.store->makeFixedOutputPathFromCA(name, TextInfo {
|
||
.hash = hashString(HashAlgorithm::SHA256, contents),
|
||
.references = std::move(refs),
|
||
})
|
||
: ({
|
||
StringSource s { contents };
|
||
state.store->addToStoreFromDump(s, name, TextIngestionMethod {}, HashAlgorithm::SHA256, refs, state.repair);
|
||
});
|
||
|
||
/* Note: we don't need to add `context' to the context of the
|
||
result, since `storePath' itself has references to the paths
|
||
used in args[1]. */
|
||
|
||
/* Add the output of this to the allowed paths. */
|
||
state.allowAndSetStorePathString(storePath, v);
|
||
}
|
||
|
||
static RegisterPrimOp primop_toFile({
|
||
.name = "__toFile",
|
||
.args = {"name", "s"},
|
||
.doc = R"(
|
||
Store the string *s* in a file in the Nix store and return its
|
||
path. The file has suffix *name*. This file can be used as an
|
||
input to derivations. One application is to write builders
|
||
“inline”. For instance, the following Nix expression combines the
|
||
Nix expression for GNU Hello and its build script into one file:
|
||
|
||
```nix
|
||
{ stdenv, fetchurl, perl }:
|
||
|
||
stdenv.mkDerivation {
|
||
name = "hello-2.1.1";
|
||
|
||
builder = builtins.toFile "builder.sh" "
|
||
source $stdenv/setup
|
||
|
||
PATH=$perl/bin:$PATH
|
||
|
||
tar xvfz $src
|
||
cd hello-*
|
||
./configure --prefix=$out
|
||
make
|
||
make install
|
||
";
|
||
|
||
src = fetchurl {
|
||
url = "http://ftp.nluug.nl/pub/gnu/hello/hello-2.1.1.tar.gz";
|
||
sha256 = "1md7jsfd8pa45z73bz1kszpp01yw6x5ljkjk2hx7wl800any6465";
|
||
};
|
||
inherit perl;
|
||
}
|
||
```
|
||
|
||
It is even possible for one file to refer to another, e.g.,
|
||
|
||
```nix
|
||
builder = let
|
||
configFile = builtins.toFile "foo.conf" "
|
||
# This is some dummy configuration file.
|
||
...
|
||
";
|
||
in builtins.toFile "builder.sh" "
|
||
source $stdenv/setup
|
||
...
|
||
cp ${configFile} $out/etc/foo.conf
|
||
";
|
||
```
|
||
|
||
Note that `${configFile}` is a
|
||
[string interpolation](@docroot@/language/values.md#type-string), so the result of the
|
||
expression `configFile`
|
||
(i.e., a path like `/nix/store/m7p7jfny445k...-foo.conf`) will be
|
||
spliced into the resulting string.
|
||
|
||
It is however *not* allowed to have files mutually referring to each
|
||
other, like so:
|
||
|
||
```nix
|
||
let
|
||
foo = builtins.toFile "foo" "...${bar}...";
|
||
bar = builtins.toFile "bar" "...${foo}...";
|
||
in foo
|
||
```
|
||
|
||
This is not allowed because it would cause a cyclic dependency in
|
||
the computation of the cryptographic hashes for `foo` and `bar`.
|
||
|
||
It is also not possible to reference the result of a derivation. If
|
||
you are using Nixpkgs, the `writeTextFile` function is able to do
|
||
that.
|
||
)",
|
||
.fun = prim_toFile,
|
||
});
|
||
|
||
bool EvalState::callPathFilter(
|
||
Value * filterFun,
|
||
const SourcePath & path,
|
||
std::string_view pathArg,
|
||
PosIdx pos)
|
||
{
|
||
auto st = path.lstat();
|
||
|
||
/* Call the filter function. The first argument is the path, the
|
||
second is a string indicating the type of the file. */
|
||
Value arg1;
|
||
arg1.mkString(pathArg);
|
||
|
||
Value arg2;
|
||
// assert that type is not "unknown"
|
||
arg2.mkString(fileTypeToString(st.type));
|
||
|
||
Value * args []{&arg1, &arg2};
|
||
Value res;
|
||
callFunction(*filterFun, 2, args, res, pos);
|
||
|
||
return forceBool(res, pos, "while evaluating the return value of the path filter function");
|
||
}
|
||
|
||
static void addPath(
|
||
EvalState & state,
|
||
const PosIdx pos,
|
||
std::string_view name,
|
||
SourcePath path,
|
||
Value * filterFun,
|
||
FileIngestionMethod method,
|
||
const std::optional<Hash> expectedHash,
|
||
Value & v,
|
||
const NixStringContext & context)
|
||
{
|
||
try {
|
||
StorePathSet refs;
|
||
|
||
if (path.accessor == state.rootFS && state.store->isInStore(path.path.abs())) {
|
||
// FIXME: handle CA derivation outputs (where path needs to
|
||
// be rewritten to the actual output).
|
||
auto rewrites = state.realiseContext(context);
|
||
path = {state.rootFS, CanonPath(state.toRealPath(rewriteStrings(path.path.abs(), rewrites), context))};
|
||
|
||
try {
|
||
auto [storePath, subPath] = state.store->toStorePath(path.path.abs());
|
||
// FIXME: we should scanForReferences on the path before adding it
|
||
refs = state.store->queryPathInfo(storePath)->references;
|
||
path = {state.rootFS, CanonPath(state.store->toRealPath(storePath) + subPath)};
|
||
} catch (Error &) { // FIXME: should be InvalidPathError
|
||
}
|
||
}
|
||
|
||
std::unique_ptr<PathFilter> filter;
|
||
if (filterFun)
|
||
filter = std::make_unique<PathFilter>([&](const Path & p) {
|
||
auto p2 = CanonPath(p);
|
||
return state.callPathFilter(filterFun, {path.accessor, p2}, p2.abs(), pos);
|
||
});
|
||
|
||
std::optional<StorePath> expectedStorePath;
|
||
if (expectedHash)
|
||
expectedStorePath = state.store->makeFixedOutputPath(name, FixedOutputInfo {
|
||
.method = method,
|
||
.hash = *expectedHash,
|
||
.references = {},
|
||
});
|
||
|
||
if (!expectedHash || !state.store->isValidPath(*expectedStorePath)) {
|
||
auto dstPath = fetchToStore(*state.store, path.resolveSymlinks(), name, method, filter.get(), state.repair);
|
||
if (expectedHash && expectedStorePath != dstPath)
|
||
state.debugThrowLastTrace(Error("store path mismatch in (possibly filtered) path added from '%s'", path));
|
||
state.allowAndSetStorePathString(dstPath, v);
|
||
} else
|
||
state.allowAndSetStorePathString(*expectedStorePath, v);
|
||
} catch (Error & e) {
|
||
e.addTrace(state.positions[pos], "while adding path '%s'", path);
|
||
throw;
|
||
}
|
||
}
|
||
|
||
|
||
static void prim_filterSource(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
NixStringContext context;
|
||
auto path = state.coerceToPath(pos, *args[1], context,
|
||
"while evaluating the second argument (the path to filter) passed to 'builtins.filterSource'");
|
||
state.forceFunction(*args[0], pos, "while evaluating the first argument passed to builtins.filterSource");
|
||
|
||
addPath(state, pos, path.baseName(), path, args[0], FileIngestionMethod::Recursive, std::nullopt, v, context);
|
||
}
|
||
|
||
static RegisterPrimOp primop_filterSource({
|
||
.name = "__filterSource",
|
||
.args = {"e1", "e2"},
|
||
.doc = R"(
|
||
> **Warning**
|
||
>
|
||
> `filterSource` should not be used to filter store paths. Since
|
||
> `filterSource` uses the name of the input directory while naming
|
||
> the output directory, doing so will produce a directory name in
|
||
> the form of `<hash2>-<hash>-<name>`, where `<hash>-<name>` is
|
||
> the name of the input directory. Since `<hash>` depends on the
|
||
> unfiltered directory, the name of the output directory will
|
||
> indirectly depend on files that are filtered out by the
|
||
> function. This will trigger a rebuild even when a filtered out
|
||
> file is changed. Use `builtins.path` instead, which allows
|
||
> specifying the name of the output directory.
|
||
|
||
This function allows you to copy sources into the Nix store while
|
||
filtering certain files. For instance, suppose that you want to use
|
||
the directory `source-dir` as an input to a Nix expression, e.g.
|
||
|
||
```nix
|
||
stdenv.mkDerivation {
|
||
...
|
||
src = ./source-dir;
|
||
}
|
||
```
|
||
|
||
However, if `source-dir` is a Subversion working copy, then all
|
||
those annoying `.svn` subdirectories will also be copied to the
|
||
store. Worse, the contents of those directories may change a lot,
|
||
causing lots of spurious rebuilds. With `filterSource` you can
|
||
filter out the `.svn` directories:
|
||
|
||
```nix
|
||
src = builtins.filterSource
|
||
(path: type: type != "directory" || baseNameOf path != ".svn")
|
||
./source-dir;
|
||
```
|
||
|
||
Thus, the first argument *e1* must be a predicate function that is
|
||
called for each regular file, directory or symlink in the source
|
||
tree *e2*. If the function returns `true`, the file is copied to the
|
||
Nix store, otherwise it is omitted. The function is called with two
|
||
arguments. The first is the full path of the file. The second is a
|
||
string that identifies the type of the file, which is either
|
||
`"regular"`, `"directory"`, `"symlink"` or `"unknown"` (for other
|
||
kinds of files such as device nodes or fifos — but note that those
|
||
cannot be copied to the Nix store, so if the predicate returns
|
||
`true` for them, the copy will fail). If you exclude a directory,
|
||
the entire corresponding subtree of *e2* will be excluded.
|
||
)",
|
||
.fun = prim_filterSource,
|
||
});
|
||
|
||
static void prim_path(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
std::optional<SourcePath> path;
|
||
std::string name;
|
||
Value * filterFun = nullptr;
|
||
auto method = FileIngestionMethod::Recursive;
|
||
std::optional<Hash> expectedHash;
|
||
NixStringContext context;
|
||
|
||
state.forceAttrs(*args[0], pos, "while evaluating the argument passed to 'builtins.path'");
|
||
|
||
for (auto & attr : *args[0]->attrs) {
|
||
auto n = state.symbols[attr.name];
|
||
if (n == "path")
|
||
path.emplace(state.coerceToPath(attr.pos, *attr.value, context, "while evaluating the 'path' attribute passed to 'builtins.path'"));
|
||
else if (attr.name == state.sName)
|
||
name = state.forceStringNoCtx(*attr.value, attr.pos, "while evaluating the `name` attribute passed to builtins.path");
|
||
else if (n == "filter")
|
||
state.forceFunction(*(filterFun = attr.value), attr.pos, "while evaluating the `filter` parameter passed to builtins.path");
|
||
else if (n == "recursive")
|
||
method = FileIngestionMethod { state.forceBool(*attr.value, attr.pos, "while evaluating the `recursive` attribute passed to builtins.path") };
|
||
else if (n == "sha256")
|
||
expectedHash = newHashAllowEmpty(state.forceStringNoCtx(*attr.value, attr.pos, "while evaluating the `sha256` attribute passed to builtins.path"), HashAlgorithm::SHA256);
|
||
else
|
||
state.debugThrowLastTrace(EvalError({
|
||
.msg = hintfmt("unsupported argument '%1%' to 'addPath'", state.symbols[attr.name]),
|
||
.errPos = state.positions[attr.pos]
|
||
}));
|
||
}
|
||
if (!path)
|
||
state.debugThrowLastTrace(EvalError({
|
||
.msg = hintfmt("missing required 'path' attribute in the first argument to builtins.path"),
|
||
.errPos = state.positions[pos]
|
||
}));
|
||
if (name.empty())
|
||
name = path->baseName();
|
||
|
||
addPath(state, pos, name, *path, filterFun, method, expectedHash, v, context);
|
||
}
|
||
|
||
static RegisterPrimOp primop_path({
|
||
.name = "__path",
|
||
.args = {"args"},
|
||
.doc = R"(
|
||
An enrichment of the built-in path type, based on the attributes
|
||
present in *args*. All are optional except `path`:
|
||
|
||
- path\
|
||
The underlying path.
|
||
|
||
- name\
|
||
The name of the path when added to the store. This can used to
|
||
reference paths that have nix-illegal characters in their names,
|
||
like `@`.
|
||
|
||
- filter\
|
||
A function of the type expected by [`builtins.filterSource`](#builtins-filterSource),
|
||
with the same semantics.
|
||
|
||
- recursive\
|
||
When `false`, when `path` is added to the store it is with a
|
||
flat hash, rather than a hash of the NAR serialization of the
|
||
file. Thus, `path` must refer to a regular file, not a
|
||
directory. This allows similar behavior to `fetchurl`. Defaults
|
||
to `true`.
|
||
|
||
- sha256\
|
||
When provided, this is the expected hash of the file at the
|
||
path. Evaluation will fail if the hash is incorrect, and
|
||
providing a hash allows `builtins.path` to be used even when the
|
||
`pure-eval` nix config option is on.
|
||
)",
|
||
.fun = prim_path,
|
||
});
|
||
|
||
|
||
/*************************************************************
|
||
* Sets
|
||
*************************************************************/
|
||
|
||
|
||
/* Return the names of the attributes in a set as a sorted list of
|
||
strings. */
|
||
static void prim_attrNames(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceAttrs(*args[0], pos, "while evaluating the argument passed to builtins.attrNames");
|
||
|
||
state.mkList(v, args[0]->attrs->size());
|
||
|
||
size_t n = 0;
|
||
for (auto & i : *args[0]->attrs)
|
||
(v.listElems()[n++] = state.allocValue())->mkString(state.symbols[i.name]);
|
||
|
||
std::sort(v.listElems(), v.listElems() + n,
|
||
[](Value * v1, Value * v2) { return strcmp(v1->c_str(), v2->c_str()) < 0; });
|
||
}
|
||
|
||
static RegisterPrimOp primop_attrNames({
|
||
.name = "__attrNames",
|
||
.args = {"set"},
|
||
.doc = R"(
|
||
Return the names of the attributes in the set *set* in an
|
||
alphabetically sorted list. For instance, `builtins.attrNames { y
|
||
= 1; x = "foo"; }` evaluates to `[ "x" "y" ]`.
|
||
)",
|
||
.fun = prim_attrNames,
|
||
});
|
||
|
||
/* Return the values of the attributes in a set as a list, in the same
|
||
order as attrNames. */
|
||
static void prim_attrValues(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceAttrs(*args[0], pos, "while evaluating the argument passed to builtins.attrValues");
|
||
|
||
state.mkList(v, args[0]->attrs->size());
|
||
|
||
unsigned int n = 0;
|
||
for (auto & i : *args[0]->attrs)
|
||
v.listElems()[n++] = (Value *) &i;
|
||
|
||
std::sort(v.listElems(), v.listElems() + n,
|
||
[&](Value * v1, Value * v2) {
|
||
std::string_view s1 = state.symbols[((Attr *) v1)->name],
|
||
s2 = state.symbols[((Attr *) v2)->name];
|
||
return s1 < s2;
|
||
});
|
||
|
||
for (unsigned int i = 0; i < n; ++i)
|
||
v.listElems()[i] = ((Attr *) v.listElems()[i])->value;
|
||
}
|
||
|
||
static RegisterPrimOp primop_attrValues({
|
||
.name = "__attrValues",
|
||
.args = {"set"},
|
||
.doc = R"(
|
||
Return the values of the attributes in the set *set* in the order
|
||
corresponding to the sorted attribute names.
|
||
)",
|
||
.fun = prim_attrValues,
|
||
});
|
||
|
||
/* Dynamic version of the `.' operator. */
|
||
void prim_getAttr(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
auto attr = state.forceStringNoCtx(*args[0], pos, "while evaluating the first argument passed to builtins.getAttr");
|
||
state.forceAttrs(*args[1], pos, "while evaluating the second argument passed to builtins.getAttr");
|
||
Bindings::iterator i = getAttr(
|
||
state,
|
||
state.symbols.create(attr),
|
||
args[1]->attrs,
|
||
"in the attribute set under consideration"
|
||
);
|
||
// !!! add to stack trace?
|
||
if (state.countCalls && i->pos) state.attrSelects[i->pos]++;
|
||
state.forceValue(*i->value, pos);
|
||
v = *i->value;
|
||
}
|
||
|
||
static RegisterPrimOp primop_getAttr({
|
||
.name = "__getAttr",
|
||
.args = {"s", "set"},
|
||
.doc = R"(
|
||
`getAttr` returns the attribute named *s* from *set*. Evaluation
|
||
aborts if the attribute doesn’t exist. This is a dynamic version of
|
||
the `.` operator, since *s* is an expression rather than an
|
||
identifier.
|
||
)",
|
||
.fun = prim_getAttr,
|
||
});
|
||
|
||
/* Return position information of the specified attribute. */
|
||
static void prim_unsafeGetAttrPos(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
auto attr = state.forceStringNoCtx(*args[0], pos, "while evaluating the first argument passed to builtins.unsafeGetAttrPos");
|
||
state.forceAttrs(*args[1], pos, "while evaluating the second argument passed to builtins.unsafeGetAttrPos");
|
||
Bindings::iterator i = args[1]->attrs->find(state.symbols.create(attr));
|
||
if (i == args[1]->attrs->end())
|
||
v.mkNull();
|
||
else
|
||
state.mkPos(v, i->pos);
|
||
}
|
||
|
||
static RegisterPrimOp primop_unsafeGetAttrPos(PrimOp {
|
||
.name = "__unsafeGetAttrPos",
|
||
.arity = 2,
|
||
.fun = prim_unsafeGetAttrPos,
|
||
});
|
||
|
||
/* Dynamic version of the `?' operator. */
|
||
static void prim_hasAttr(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
auto attr = state.forceStringNoCtx(*args[0], pos, "while evaluating the first argument passed to builtins.hasAttr");
|
||
state.forceAttrs(*args[1], pos, "while evaluating the second argument passed to builtins.hasAttr");
|
||
v.mkBool(args[1]->attrs->find(state.symbols.create(attr)) != args[1]->attrs->end());
|
||
}
|
||
|
||
static RegisterPrimOp primop_hasAttr({
|
||
.name = "__hasAttr",
|
||
.args = {"s", "set"},
|
||
.doc = R"(
|
||
`hasAttr` returns `true` if *set* has an attribute named *s*, and
|
||
`false` otherwise. This is a dynamic version of the `?` operator,
|
||
since *s* is an expression rather than an identifier.
|
||
)",
|
||
.fun = prim_hasAttr,
|
||
});
|
||
|
||
/* Determine whether the argument is a set. */
|
||
static void prim_isAttrs(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceValue(*args[0], pos);
|
||
v.mkBool(args[0]->type() == nAttrs);
|
||
}
|
||
|
||
static RegisterPrimOp primop_isAttrs({
|
||
.name = "__isAttrs",
|
||
.args = {"e"},
|
||
.doc = R"(
|
||
Return `true` if *e* evaluates to a set, and `false` otherwise.
|
||
)",
|
||
.fun = prim_isAttrs,
|
||
});
|
||
|
||
static void prim_removeAttrs(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceAttrs(*args[0], pos, "while evaluating the first argument passed to builtins.removeAttrs");
|
||
state.forceList(*args[1], pos, "while evaluating the second argument passed to builtins.removeAttrs");
|
||
|
||
/* Get the attribute names to be removed.
|
||
We keep them as Attrs instead of Symbols so std::set_difference
|
||
can be used to remove them from attrs[0]. */
|
||
// 64: large enough to fit the attributes of a derivation
|
||
boost::container::small_vector<Attr, 64> names;
|
||
names.reserve(args[1]->listSize());
|
||
for (auto elem : args[1]->listItems()) {
|
||
state.forceStringNoCtx(*elem, pos, "while evaluating the values of the second argument passed to builtins.removeAttrs");
|
||
names.emplace_back(state.symbols.create(elem->string_view()), nullptr);
|
||
}
|
||
std::sort(names.begin(), names.end());
|
||
|
||
/* Copy all attributes not in that set. Note that we don't need
|
||
to sort v.attrs because it's a subset of an already sorted
|
||
vector. */
|
||
auto attrs = state.buildBindings(args[0]->attrs->size());
|
||
std::set_difference(
|
||
args[0]->attrs->begin(), args[0]->attrs->end(),
|
||
names.begin(), names.end(),
|
||
std::back_inserter(attrs));
|
||
v.mkAttrs(attrs.alreadySorted());
|
||
}
|
||
|
||
static RegisterPrimOp primop_removeAttrs({
|
||
.name = "removeAttrs",
|
||
.args = {"set", "list"},
|
||
.doc = R"(
|
||
Remove the attributes listed in *list* from *set*. The attributes
|
||
don’t have to exist in *set*. For instance,
|
||
|
||
```nix
|
||
removeAttrs { x = 1; y = 2; z = 3; } [ "a" "x" "z" ]
|
||
```
|
||
|
||
evaluates to `{ y = 2; }`.
|
||
)",
|
||
.fun = prim_removeAttrs,
|
||
});
|
||
|
||
/* Builds a set from a list specifying (name, value) pairs. To be
|
||
precise, a list [{name = "name1"; value = value1;} ... {name =
|
||
"nameN"; value = valueN;}] is transformed to {name1 = value1;
|
||
... nameN = valueN;}. In case of duplicate occurrences of the same
|
||
name, the first takes precedence. */
|
||
static void prim_listToAttrs(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceList(*args[0], pos, "while evaluating the argument passed to builtins.listToAttrs");
|
||
|
||
auto attrs = state.buildBindings(args[0]->listSize());
|
||
|
||
std::set<Symbol> seen;
|
||
|
||
for (auto v2 : args[0]->listItems()) {
|
||
state.forceAttrs(*v2, pos, "while evaluating an element of the list passed to builtins.listToAttrs");
|
||
|
||
Bindings::iterator j = getAttr(state, state.sName, v2->attrs, "in a {name=...; value=...;} pair");
|
||
|
||
auto name = state.forceStringNoCtx(*j->value, j->pos, "while evaluating the `name` attribute of an element of the list passed to builtins.listToAttrs");
|
||
|
||
auto sym = state.symbols.create(name);
|
||
if (seen.insert(sym).second) {
|
||
Bindings::iterator j2 = getAttr(state, state.sValue, v2->attrs, "in a {name=...; value=...;} pair");
|
||
attrs.insert(sym, j2->value, j2->pos);
|
||
}
|
||
}
|
||
|
||
v.mkAttrs(attrs);
|
||
}
|
||
|
||
static RegisterPrimOp primop_listToAttrs({
|
||
.name = "__listToAttrs",
|
||
.args = {"e"},
|
||
.doc = R"(
|
||
Construct a set from a list specifying the names and values of each
|
||
attribute. Each element of the list should be a set consisting of a
|
||
string-valued attribute `name` specifying the name of the attribute,
|
||
and an attribute `value` specifying its value.
|
||
|
||
In case of duplicate occurrences of the same name, the first
|
||
takes precedence.
|
||
|
||
Example:
|
||
|
||
```nix
|
||
builtins.listToAttrs
|
||
[ { name = "foo"; value = 123; }
|
||
{ name = "bar"; value = 456; }
|
||
{ name = "bar"; value = 420; }
|
||
]
|
||
```
|
||
|
||
evaluates to
|
||
|
||
```nix
|
||
{ foo = 123; bar = 456; }
|
||
```
|
||
)",
|
||
.fun = prim_listToAttrs,
|
||
});
|
||
|
||
static void prim_intersectAttrs(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceAttrs(*args[0], pos, "while evaluating the first argument passed to builtins.intersectAttrs");
|
||
state.forceAttrs(*args[1], pos, "while evaluating the second argument passed to builtins.intersectAttrs");
|
||
|
||
Bindings &left = *args[0]->attrs;
|
||
Bindings &right = *args[1]->attrs;
|
||
|
||
auto attrs = state.buildBindings(std::min(left.size(), right.size()));
|
||
|
||
// The current implementation has good asymptotic complexity and is reasonably
|
||
// simple. Further optimization may be possible, but does not seem productive,
|
||
// considering the state of eval performance in 2022.
|
||
//
|
||
// I have looked for reusable and/or standard solutions and these are my
|
||
// findings:
|
||
//
|
||
// STL
|
||
// ===
|
||
// std::set_intersection is not suitable, as it only performs a simultaneous
|
||
// linear scan; not taking advantage of random access. This is O(n + m), so
|
||
// linear in the largest set, which is not acceptable for callPackage in Nixpkgs.
|
||
//
|
||
// Simultaneous scan, with alternating simple binary search
|
||
// ===
|
||
// One alternative algorithm scans the attrsets simultaneously, jumping
|
||
// forward using `lower_bound` in case of inequality. This should perform
|
||
// well on very similar sets, having a local and predictable access pattern.
|
||
// On dissimilar sets, it seems to need more comparisons than the current
|
||
// algorithm, as few consecutive attrs match. `lower_bound` could take
|
||
// advantage of the decreasing remaining search space, but this causes
|
||
// the medians to move, which can mean that they don't stay in the cache
|
||
// like they would with the current naive `find`.
|
||
//
|
||
// Double binary search
|
||
// ===
|
||
// The optimal algorithm may be "Double binary search", which doesn't
|
||
// scan at all, but rather divides both sets simultaneously.
|
||
// See "Fast Intersection Algorithms for Sorted Sequences" by Baeza-Yates et al.
|
||
// https://cs.uwaterloo.ca/~ajsaling/papers/intersection_alg_app10.pdf
|
||
// The only downsides I can think of are not having a linear access pattern
|
||
// for similar sets, and having to maintain a more intricate algorithm.
|
||
//
|
||
// Adaptive
|
||
// ===
|
||
// Finally one could run try a simultaneous scan, count misses and fall back
|
||
// to double binary search when the counter hit some threshold and/or ratio.
|
||
|
||
if (left.size() < right.size()) {
|
||
for (auto & l : left) {
|
||
Bindings::iterator r = right.find(l.name);
|
||
if (r != right.end())
|
||
attrs.insert(*r);
|
||
}
|
||
}
|
||
else {
|
||
for (auto & r : right) {
|
||
Bindings::iterator l = left.find(r.name);
|
||
if (l != left.end())
|
||
attrs.insert(r);
|
||
}
|
||
}
|
||
|
||
v.mkAttrs(attrs.alreadySorted());
|
||
}
|
||
|
||
static RegisterPrimOp primop_intersectAttrs({
|
||
.name = "__intersectAttrs",
|
||
.args = {"e1", "e2"},
|
||
.doc = R"(
|
||
Return a set consisting of the attributes in the set *e2* which have the
|
||
same name as some attribute in *e1*.
|
||
|
||
Performs in O(*n* log *m*) where *n* is the size of the smaller set and *m* the larger set's size.
|
||
)",
|
||
.fun = prim_intersectAttrs,
|
||
});
|
||
|
||
static void prim_catAttrs(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
auto attrName = state.symbols.create(state.forceStringNoCtx(*args[0], pos, "while evaluating the first argument passed to builtins.catAttrs"));
|
||
state.forceList(*args[1], pos, "while evaluating the second argument passed to builtins.catAttrs");
|
||
|
||
SmallValueVector<nonRecursiveStackReservation> res(args[1]->listSize());
|
||
size_t found = 0;
|
||
|
||
for (auto v2 : args[1]->listItems()) {
|
||
state.forceAttrs(*v2, pos, "while evaluating an element in the list passed as second argument to builtins.catAttrs");
|
||
Bindings::iterator i = v2->attrs->find(attrName);
|
||
if (i != v2->attrs->end())
|
||
res[found++] = i->value;
|
||
}
|
||
|
||
state.mkList(v, found);
|
||
for (unsigned int n = 0; n < found; ++n)
|
||
v.listElems()[n] = res[n];
|
||
}
|
||
|
||
static RegisterPrimOp primop_catAttrs({
|
||
.name = "__catAttrs",
|
||
.args = {"attr", "list"},
|
||
.doc = R"(
|
||
Collect each attribute named *attr* from a list of attribute
|
||
sets. Attrsets that don't contain the named attribute are
|
||
ignored. For example,
|
||
|
||
```nix
|
||
builtins.catAttrs "a" [{a = 1;} {b = 0;} {a = 2;}]
|
||
```
|
||
|
||
evaluates to `[1 2]`.
|
||
)",
|
||
.fun = prim_catAttrs,
|
||
});
|
||
|
||
static void prim_functionArgs(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceValue(*args[0], pos);
|
||
if (args[0]->isPrimOpApp() || args[0]->isPrimOp()) {
|
||
v.mkAttrs(&state.emptyBindings);
|
||
return;
|
||
}
|
||
if (!args[0]->isLambda())
|
||
state.debugThrowLastTrace(TypeError({
|
||
.msg = hintfmt("'functionArgs' requires a function"),
|
||
.errPos = state.positions[pos]
|
||
}));
|
||
|
||
if (!args[0]->lambda.fun->hasFormals()) {
|
||
v.mkAttrs(&state.emptyBindings);
|
||
return;
|
||
}
|
||
|
||
auto attrs = state.buildBindings(args[0]->lambda.fun->formals->formals.size());
|
||
for (auto & i : args[0]->lambda.fun->formals->formals)
|
||
// !!! should optimise booleans (allocate only once)
|
||
attrs.alloc(i.name, i.pos).mkBool(i.def);
|
||
v.mkAttrs(attrs);
|
||
}
|
||
|
||
static RegisterPrimOp primop_functionArgs({
|
||
.name = "__functionArgs",
|
||
.args = {"f"},
|
||
.doc = R"(
|
||
Return a set containing the names of the formal arguments expected
|
||
by the function *f*. The value of each attribute is a Boolean
|
||
denoting whether the corresponding argument has a default value. For
|
||
instance, `functionArgs ({ x, y ? 123}: ...) = { x = false; y =
|
||
true; }`.
|
||
|
||
"Formal argument" here refers to the attributes pattern-matched by
|
||
the function. Plain lambdas are not included, e.g. `functionArgs (x:
|
||
...) = { }`.
|
||
)",
|
||
.fun = prim_functionArgs,
|
||
});
|
||
|
||
/* */
|
||
static void prim_mapAttrs(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceAttrs(*args[1], pos, "while evaluating the second argument passed to builtins.mapAttrs");
|
||
|
||
auto attrs = state.buildBindings(args[1]->attrs->size());
|
||
|
||
for (auto & i : *args[1]->attrs) {
|
||
Value * vName = state.allocValue();
|
||
Value * vFun2 = state.allocValue();
|
||
vName->mkString(state.symbols[i.name]);
|
||
vFun2->mkApp(args[0], vName);
|
||
attrs.alloc(i.name).mkApp(vFun2, i.value);
|
||
}
|
||
|
||
v.mkAttrs(attrs.alreadySorted());
|
||
}
|
||
|
||
static RegisterPrimOp primop_mapAttrs({
|
||
.name = "__mapAttrs",
|
||
.args = {"f", "attrset"},
|
||
.doc = R"(
|
||
Apply function *f* to every element of *attrset*. For example,
|
||
|
||
```nix
|
||
builtins.mapAttrs (name: value: value * 10) { a = 1; b = 2; }
|
||
```
|
||
|
||
evaluates to `{ a = 10; b = 20; }`.
|
||
)",
|
||
.fun = prim_mapAttrs,
|
||
});
|
||
|
||
static void prim_zipAttrsWith(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
// we will first count how many values are present for each given key.
|
||
// we then allocate a single attrset and pre-populate it with lists of
|
||
// appropriate sizes, stash the pointers to the list elements of each,
|
||
// and populate the lists. after that we replace the list in the every
|
||
// attribute with the merge function application. this way we need not
|
||
// use (slightly slower) temporary storage the GC does not know about.
|
||
|
||
std::map<Symbol, std::pair<size_t, Value * *>> attrsSeen;
|
||
|
||
state.forceFunction(*args[0], pos, "while evaluating the first argument passed to builtins.zipAttrsWith");
|
||
state.forceList(*args[1], pos, "while evaluating the second argument passed to builtins.zipAttrsWith");
|
||
const auto listSize = args[1]->listSize();
|
||
const auto listElems = args[1]->listElems();
|
||
|
||
for (unsigned int n = 0; n < listSize; ++n) {
|
||
Value * vElem = listElems[n];
|
||
state.forceAttrs(*vElem, noPos, "while evaluating a value of the list passed as second argument to builtins.zipAttrsWith");
|
||
for (auto & attr : *vElem->attrs)
|
||
attrsSeen[attr.name].first++;
|
||
}
|
||
|
||
auto attrs = state.buildBindings(attrsSeen.size());
|
||
for (auto & [sym, elem] : attrsSeen) {
|
||
auto & list = attrs.alloc(sym);
|
||
state.mkList(list, elem.first);
|
||
elem.second = list.listElems();
|
||
}
|
||
v.mkAttrs(attrs.alreadySorted());
|
||
|
||
for (unsigned int n = 0; n < listSize; ++n) {
|
||
Value * vElem = listElems[n];
|
||
for (auto & attr : *vElem->attrs)
|
||
*attrsSeen[attr.name].second++ = attr.value;
|
||
}
|
||
|
||
for (auto & attr : *v.attrs) {
|
||
auto name = state.allocValue();
|
||
name->mkString(state.symbols[attr.name]);
|
||
auto call1 = state.allocValue();
|
||
call1->mkApp(args[0], name);
|
||
auto call2 = state.allocValue();
|
||
call2->mkApp(call1, attr.value);
|
||
attr.value = call2;
|
||
}
|
||
}
|
||
|
||
static RegisterPrimOp primop_zipAttrsWith({
|
||
.name = "__zipAttrsWith",
|
||
.args = {"f", "list"},
|
||
.doc = R"(
|
||
Transpose a list of attribute sets into an attribute set of lists,
|
||
then apply `mapAttrs`.
|
||
|
||
`f` receives two arguments: the attribute name and a non-empty
|
||
list of all values encountered for that attribute name.
|
||
|
||
The result is an attribute set where the attribute names are the
|
||
union of the attribute names in each element of `list`. The attribute
|
||
values are the return values of `f`.
|
||
|
||
```nix
|
||
builtins.zipAttrsWith
|
||
(name: values: { inherit name values; })
|
||
[ { a = "x"; } { a = "y"; b = "z"; } ]
|
||
```
|
||
|
||
evaluates to
|
||
|
||
```
|
||
{
|
||
a = { name = "a"; values = [ "x" "y" ]; };
|
||
b = { name = "b"; values = [ "z" ]; };
|
||
}
|
||
```
|
||
)",
|
||
.fun = prim_zipAttrsWith,
|
||
});
|
||
|
||
|
||
/*************************************************************
|
||
* Lists
|
||
*************************************************************/
|
||
|
||
|
||
/* Determine whether the argument is a list. */
|
||
static void prim_isList(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceValue(*args[0], pos);
|
||
v.mkBool(args[0]->type() == nList);
|
||
}
|
||
|
||
static RegisterPrimOp primop_isList({
|
||
.name = "__isList",
|
||
.args = {"e"},
|
||
.doc = R"(
|
||
Return `true` if *e* evaluates to a list, and `false` otherwise.
|
||
)",
|
||
.fun = prim_isList,
|
||
});
|
||
|
||
static void elemAt(EvalState & state, const PosIdx pos, Value & list, int n, Value & v)
|
||
{
|
||
state.forceList(list, pos, "while evaluating the first argument passed to builtins.elemAt");
|
||
if (n < 0 || (unsigned int) n >= list.listSize())
|
||
state.debugThrowLastTrace(Error({
|
||
.msg = hintfmt("list index %1% is out of bounds", n),
|
||
.errPos = state.positions[pos]
|
||
}));
|
||
state.forceValue(*list.listElems()[n], pos);
|
||
v = *list.listElems()[n];
|
||
}
|
||
|
||
/* Return the n-1'th element of a list. */
|
||
static void prim_elemAt(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
elemAt(state, pos, *args[0], state.forceInt(*args[1], pos, "while evaluating the second argument passed to builtins.elemAt"), v);
|
||
}
|
||
|
||
static RegisterPrimOp primop_elemAt({
|
||
.name = "__elemAt",
|
||
.args = {"xs", "n"},
|
||
.doc = R"(
|
||
Return element *n* from the list *xs*. Elements are counted starting
|
||
from 0. A fatal error occurs if the index is out of bounds.
|
||
)",
|
||
.fun = prim_elemAt,
|
||
});
|
||
|
||
/* Return the first element of a list. */
|
||
static void prim_head(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
elemAt(state, pos, *args[0], 0, v);
|
||
}
|
||
|
||
static RegisterPrimOp primop_head({
|
||
.name = "__head",
|
||
.args = {"list"},
|
||
.doc = R"(
|
||
Return the first element of a list; abort evaluation if the argument
|
||
isn’t a list or is an empty list. You can test whether a list is
|
||
empty by comparing it with `[]`.
|
||
)",
|
||
.fun = prim_head,
|
||
});
|
||
|
||
/* Return a list consisting of everything but the first element of
|
||
a list. Warning: this function takes O(n) time, so you probably
|
||
don't want to use it! */
|
||
static void prim_tail(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceList(*args[0], pos, "while evaluating the first argument passed to builtins.tail");
|
||
if (args[0]->listSize() == 0)
|
||
state.debugThrowLastTrace(Error({
|
||
.msg = hintfmt("'tail' called on an empty list"),
|
||
.errPos = state.positions[pos]
|
||
}));
|
||
|
||
state.mkList(v, args[0]->listSize() - 1);
|
||
for (unsigned int n = 0; n < v.listSize(); ++n)
|
||
v.listElems()[n] = args[0]->listElems()[n + 1];
|
||
}
|
||
|
||
static RegisterPrimOp primop_tail({
|
||
.name = "__tail",
|
||
.args = {"list"},
|
||
.doc = R"(
|
||
Return the list without its first item; abort evaluation if
|
||
the argument isn’t a list or is an empty list.
|
||
|
||
> **Warning**
|
||
>
|
||
> This function should generally be avoided since it's inefficient:
|
||
> unlike Haskell's `tail`, it takes O(n) time, so recursing over a
|
||
> list by repeatedly calling `tail` takes O(n^2) time.
|
||
)",
|
||
.fun = prim_tail,
|
||
});
|
||
|
||
/* Apply a function to every element of a list. */
|
||
static void prim_map(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceList(*args[1], pos, "while evaluating the second argument passed to builtins.map");
|
||
|
||
if (args[1]->listSize() == 0) {
|
||
v = *args[1];
|
||
return;
|
||
}
|
||
|
||
state.forceFunction(*args[0], pos, "while evaluating the first argument passed to builtins.map");
|
||
|
||
state.mkList(v, args[1]->listSize());
|
||
for (unsigned int n = 0; n < v.listSize(); ++n)
|
||
(v.listElems()[n] = state.allocValue())->mkApp(
|
||
args[0], args[1]->listElems()[n]);
|
||
}
|
||
|
||
static RegisterPrimOp primop_map({
|
||
.name = "map",
|
||
.args = {"f", "list"},
|
||
.doc = R"(
|
||
Apply the function *f* to each element in the list *list*. For
|
||
example,
|
||
|
||
```nix
|
||
map (x: "foo" + x) [ "bar" "bla" "abc" ]
|
||
```
|
||
|
||
evaluates to `[ "foobar" "foobla" "fooabc" ]`.
|
||
)",
|
||
.fun = prim_map,
|
||
});
|
||
|
||
/* Filter a list using a predicate; that is, return a list containing
|
||
every element from the list for which the predicate function
|
||
returns true. */
|
||
static void prim_filter(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceList(*args[1], pos, "while evaluating the second argument passed to builtins.filter");
|
||
|
||
if (args[1]->listSize() == 0) {
|
||
v = *args[1];
|
||
return;
|
||
}
|
||
|
||
state.forceFunction(*args[0], pos, "while evaluating the first argument passed to builtins.filter");
|
||
|
||
SmallValueVector<nonRecursiveStackReservation> vs(args[1]->listSize());
|
||
size_t k = 0;
|
||
|
||
bool same = true;
|
||
for (unsigned int n = 0; n < args[1]->listSize(); ++n) {
|
||
Value res;
|
||
state.callFunction(*args[0], *args[1]->listElems()[n], res, noPos);
|
||
if (state.forceBool(res, pos, "while evaluating the return value of the filtering function passed to builtins.filter"))
|
||
vs[k++] = args[1]->listElems()[n];
|
||
else
|
||
same = false;
|
||
}
|
||
|
||
if (same)
|
||
v = *args[1];
|
||
else {
|
||
state.mkList(v, k);
|
||
for (unsigned int n = 0; n < k; ++n) v.listElems()[n] = vs[n];
|
||
}
|
||
}
|
||
|
||
static RegisterPrimOp primop_filter({
|
||
.name = "__filter",
|
||
.args = {"f", "list"},
|
||
.doc = R"(
|
||
Return a list consisting of the elements of *list* for which the
|
||
function *f* returns `true`.
|
||
)",
|
||
.fun = prim_filter,
|
||
});
|
||
|
||
/* Return true if a list contains a given element. */
|
||
static void prim_elem(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
bool res = false;
|
||
state.forceList(*args[1], pos, "while evaluating the second argument passed to builtins.elem");
|
||
for (auto elem : args[1]->listItems())
|
||
if (state.eqValues(*args[0], *elem, pos, "while searching for the presence of the given element in the list")) {
|
||
res = true;
|
||
break;
|
||
}
|
||
v.mkBool(res);
|
||
}
|
||
|
||
static RegisterPrimOp primop_elem({
|
||
.name = "__elem",
|
||
.args = {"x", "xs"},
|
||
.doc = R"(
|
||
Return `true` if a value equal to *x* occurs in the list *xs*, and
|
||
`false` otherwise.
|
||
)",
|
||
.fun = prim_elem,
|
||
});
|
||
|
||
/* Concatenate a list of lists. */
|
||
static void prim_concatLists(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceList(*args[0], pos, "while evaluating the first argument passed to builtins.concatLists");
|
||
state.concatLists(v, args[0]->listSize(), args[0]->listElems(), pos, "while evaluating a value of the list passed to builtins.concatLists");
|
||
}
|
||
|
||
static RegisterPrimOp primop_concatLists({
|
||
.name = "__concatLists",
|
||
.args = {"lists"},
|
||
.doc = R"(
|
||
Concatenate a list of lists into a single list.
|
||
)",
|
||
.fun = prim_concatLists,
|
||
});
|
||
|
||
/* Return the length of a list. This is an O(1) time operation. */
|
||
static void prim_length(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceList(*args[0], pos, "while evaluating the first argument passed to builtins.length");
|
||
v.mkInt(args[0]->listSize());
|
||
}
|
||
|
||
static RegisterPrimOp primop_length({
|
||
.name = "__length",
|
||
.args = {"e"},
|
||
.doc = R"(
|
||
Return the length of the list *e*.
|
||
)",
|
||
.fun = prim_length,
|
||
});
|
||
|
||
/* Reduce a list by applying a binary operator, from left to
|
||
right. The operator is applied strictly. */
|
||
static void prim_foldlStrict(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceFunction(*args[0], pos, "while evaluating the first argument passed to builtins.foldlStrict");
|
||
state.forceList(*args[2], pos, "while evaluating the third argument passed to builtins.foldlStrict");
|
||
|
||
if (args[2]->listSize()) {
|
||
Value * vCur = args[1];
|
||
|
||
for (auto [n, elem] : enumerate(args[2]->listItems())) {
|
||
Value * vs []{vCur, elem};
|
||
vCur = n == args[2]->listSize() - 1 ? &v : state.allocValue();
|
||
state.callFunction(*args[0], 2, vs, *vCur, pos);
|
||
}
|
||
state.forceValue(v, pos);
|
||
} else {
|
||
state.forceValue(*args[1], pos);
|
||
v = *args[1];
|
||
}
|
||
}
|
||
|
||
static RegisterPrimOp primop_foldlStrict({
|
||
.name = "__foldl'",
|
||
.args = {"op", "nul", "list"},
|
||
.doc = R"(
|
||
Reduce a list by applying a binary operator, from left to right,
|
||
e.g. `foldl' op nul [x0 x1 x2 ...] = op (op (op nul x0) x1) x2)
|
||
...`.
|
||
|
||
For example, `foldl' (acc: elem: acc + elem) 0 [1 2 3]` evaluates
|
||
to `6` and `foldl' (acc: elem: { "${elem}" = elem; } // acc) {}
|
||
["a" "b"]` evaluates to `{ a = "a"; b = "b"; }`.
|
||
|
||
The first argument of `op` is the accumulator whereas the second
|
||
argument is the current element being processed. The return value
|
||
of each application of `op` is evaluated immediately, even for
|
||
intermediate values.
|
||
)",
|
||
.fun = prim_foldlStrict,
|
||
});
|
||
|
||
static void anyOrAll(bool any, EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceFunction(*args[0], pos, std::string("while evaluating the first argument passed to builtins.") + (any ? "any" : "all"));
|
||
state.forceList(*args[1], pos, std::string("while evaluating the second argument passed to builtins.") + (any ? "any" : "all"));
|
||
|
||
std::string_view errorCtx = any
|
||
? "while evaluating the return value of the function passed to builtins.any"
|
||
: "while evaluating the return value of the function passed to builtins.all";
|
||
|
||
Value vTmp;
|
||
for (auto elem : args[1]->listItems()) {
|
||
state.callFunction(*args[0], *elem, vTmp, pos);
|
||
bool res = state.forceBool(vTmp, pos, errorCtx);
|
||
if (res == any) {
|
||
v.mkBool(any);
|
||
return;
|
||
}
|
||
}
|
||
|
||
v.mkBool(!any);
|
||
}
|
||
|
||
|
||
static void prim_any(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
anyOrAll(true, state, pos, args, v);
|
||
}
|
||
|
||
static RegisterPrimOp primop_any({
|
||
.name = "__any",
|
||
.args = {"pred", "list"},
|
||
.doc = R"(
|
||
Return `true` if the function *pred* returns `true` for at least one
|
||
element of *list*, and `false` otherwise.
|
||
)",
|
||
.fun = prim_any,
|
||
});
|
||
|
||
static void prim_all(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
anyOrAll(false, state, pos, args, v);
|
||
}
|
||
|
||
static RegisterPrimOp primop_all({
|
||
.name = "__all",
|
||
.args = {"pred", "list"},
|
||
.doc = R"(
|
||
Return `true` if the function *pred* returns `true` for all elements
|
||
of *list*, and `false` otherwise.
|
||
)",
|
||
.fun = prim_all,
|
||
});
|
||
|
||
static void prim_genList(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
auto len = state.forceInt(*args[1], pos, "while evaluating the second argument passed to builtins.genList");
|
||
|
||
if (len < 0)
|
||
state.error("cannot create list of size %1%", len).debugThrow<EvalError>();
|
||
|
||
// More strict than striclty (!) necessary, but acceptable
|
||
// as evaluating map without accessing any values makes little sense.
|
||
state.forceFunction(*args[0], noPos, "while evaluating the first argument passed to builtins.genList");
|
||
|
||
state.mkList(v, len);
|
||
for (unsigned int n = 0; n < (unsigned int) len; ++n) {
|
||
auto arg = state.allocValue();
|
||
arg->mkInt(n);
|
||
(v.listElems()[n] = state.allocValue())->mkApp(args[0], arg);
|
||
}
|
||
}
|
||
|
||
static RegisterPrimOp primop_genList({
|
||
.name = "__genList",
|
||
.args = {"generator", "length"},
|
||
.doc = R"(
|
||
Generate list of size *length*, with each element *i* equal to the
|
||
value returned by *generator* `i`. For example,
|
||
|
||
```nix
|
||
builtins.genList (x: x * x) 5
|
||
```
|
||
|
||
returns the list `[ 0 1 4 9 16 ]`.
|
||
)",
|
||
.fun = prim_genList,
|
||
});
|
||
|
||
static void prim_lessThan(EvalState & state, const PosIdx pos, Value * * args, Value & v);
|
||
|
||
|
||
static void prim_sort(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceList(*args[1], pos, "while evaluating the second argument passed to builtins.sort");
|
||
|
||
auto len = args[1]->listSize();
|
||
if (len == 0) {
|
||
v = *args[1];
|
||
return;
|
||
}
|
||
|
||
state.forceFunction(*args[0], pos, "while evaluating the first argument passed to builtins.sort");
|
||
|
||
state.mkList(v, len);
|
||
for (unsigned int n = 0; n < len; ++n) {
|
||
state.forceValue(*args[1]->listElems()[n], pos);
|
||
v.listElems()[n] = args[1]->listElems()[n];
|
||
}
|
||
|
||
auto comparator = [&](Value * a, Value * b) {
|
||
/* Optimization: if the comparator is lessThan, bypass
|
||
callFunction. */
|
||
/* TODO: (layus) this is absurd. An optimisation like this
|
||
should be outside the lambda creation */
|
||
if (args[0]->isPrimOp() && args[0]->primOp->fun == prim_lessThan)
|
||
return CompareValues(state, noPos, "while evaluating the ordering function passed to builtins.sort")(a, b);
|
||
|
||
Value * vs[] = {a, b};
|
||
Value vBool;
|
||
state.callFunction(*args[0], 2, vs, vBool, noPos);
|
||
return state.forceBool(vBool, pos, "while evaluating the return value of the sorting function passed to builtins.sort");
|
||
};
|
||
|
||
/* FIXME: std::sort can segfault if the comparator is not a strict
|
||
weak ordering. What to do? std::stable_sort() seems more
|
||
resilient, but no guarantees... */
|
||
std::stable_sort(v.listElems(), v.listElems() + len, comparator);
|
||
}
|
||
|
||
static RegisterPrimOp primop_sort({
|
||
.name = "__sort",
|
||
.args = {"comparator", "list"},
|
||
.doc = R"(
|
||
Return *list* in sorted order. It repeatedly calls the function
|
||
*comparator* with two elements. The comparator should return `true`
|
||
if the first element is less than the second, and `false` otherwise.
|
||
For example,
|
||
|
||
```nix
|
||
builtins.sort builtins.lessThan [ 483 249 526 147 42 77 ]
|
||
```
|
||
|
||
produces the list `[ 42 77 147 249 483 526 ]`.
|
||
|
||
This is a stable sort: it preserves the relative order of elements
|
||
deemed equal by the comparator.
|
||
)",
|
||
.fun = prim_sort,
|
||
});
|
||
|
||
static void prim_partition(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceFunction(*args[0], pos, "while evaluating the first argument passed to builtins.partition");
|
||
state.forceList(*args[1], pos, "while evaluating the second argument passed to builtins.partition");
|
||
|
||
auto len = args[1]->listSize();
|
||
|
||
ValueVector right, wrong;
|
||
|
||
for (unsigned int n = 0; n < len; ++n) {
|
||
auto vElem = args[1]->listElems()[n];
|
||
state.forceValue(*vElem, pos);
|
||
Value res;
|
||
state.callFunction(*args[0], *vElem, res, pos);
|
||
if (state.forceBool(res, pos, "while evaluating the return value of the partition function passed to builtins.partition"))
|
||
right.push_back(vElem);
|
||
else
|
||
wrong.push_back(vElem);
|
||
}
|
||
|
||
auto attrs = state.buildBindings(2);
|
||
|
||
auto & vRight = attrs.alloc(state.sRight);
|
||
auto rsize = right.size();
|
||
state.mkList(vRight, rsize);
|
||
if (rsize)
|
||
memcpy(vRight.listElems(), right.data(), sizeof(Value *) * rsize);
|
||
|
||
auto & vWrong = attrs.alloc(state.sWrong);
|
||
auto wsize = wrong.size();
|
||
state.mkList(vWrong, wsize);
|
||
if (wsize)
|
||
memcpy(vWrong.listElems(), wrong.data(), sizeof(Value *) * wsize);
|
||
|
||
v.mkAttrs(attrs);
|
||
}
|
||
|
||
static RegisterPrimOp primop_partition({
|
||
.name = "__partition",
|
||
.args = {"pred", "list"},
|
||
.doc = R"(
|
||
Given a predicate function *pred*, this function returns an
|
||
attrset containing a list named `right`, containing the elements
|
||
in *list* for which *pred* returned `true`, and a list named
|
||
`wrong`, containing the elements for which it returned
|
||
`false`. For example,
|
||
|
||
```nix
|
||
builtins.partition (x: x > 10) [1 23 9 3 42]
|
||
```
|
||
|
||
evaluates to
|
||
|
||
```nix
|
||
{ right = [ 23 42 ]; wrong = [ 1 9 3 ]; }
|
||
```
|
||
)",
|
||
.fun = prim_partition,
|
||
});
|
||
|
||
static void prim_groupBy(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceFunction(*args[0], pos, "while evaluating the first argument passed to builtins.groupBy");
|
||
state.forceList(*args[1], pos, "while evaluating the second argument passed to builtins.groupBy");
|
||
|
||
ValueVectorMap attrs;
|
||
|
||
for (auto vElem : args[1]->listItems()) {
|
||
Value res;
|
||
state.callFunction(*args[0], *vElem, res, pos);
|
||
auto name = state.forceStringNoCtx(res, pos, "while evaluating the return value of the grouping function passed to builtins.groupBy");
|
||
auto sym = state.symbols.create(name);
|
||
auto vector = attrs.try_emplace(sym, ValueVector()).first;
|
||
vector->second.push_back(vElem);
|
||
}
|
||
|
||
auto attrs2 = state.buildBindings(attrs.size());
|
||
|
||
for (auto & i : attrs) {
|
||
auto & list = attrs2.alloc(i.first);
|
||
auto size = i.second.size();
|
||
state.mkList(list, size);
|
||
memcpy(list.listElems(), i.second.data(), sizeof(Value *) * size);
|
||
}
|
||
|
||
v.mkAttrs(attrs2.alreadySorted());
|
||
}
|
||
|
||
static RegisterPrimOp primop_groupBy({
|
||
.name = "__groupBy",
|
||
.args = {"f", "list"},
|
||
.doc = R"(
|
||
Groups elements of *list* together by the string returned from the
|
||
function *f* called on each element. It returns an attribute set
|
||
where each attribute value contains the elements of *list* that are
|
||
mapped to the same corresponding attribute name returned by *f*.
|
||
|
||
For example,
|
||
|
||
```nix
|
||
builtins.groupBy (builtins.substring 0 1) ["foo" "bar" "baz"]
|
||
```
|
||
|
||
evaluates to
|
||
|
||
```nix
|
||
{ b = [ "bar" "baz" ]; f = [ "foo" ]; }
|
||
```
|
||
)",
|
||
.fun = prim_groupBy,
|
||
});
|
||
|
||
static void prim_concatMap(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceFunction(*args[0], pos, "while evaluating the first argument passed to builtins.concatMap");
|
||
state.forceList(*args[1], pos, "while evaluating the second argument passed to builtins.concatMap");
|
||
auto nrLists = args[1]->listSize();
|
||
|
||
// List of returned lists before concatenation. References to these Values must NOT be persisted.
|
||
SmallTemporaryValueVector<conservativeStackReservation> lists(nrLists);
|
||
size_t len = 0;
|
||
|
||
for (unsigned int n = 0; n < nrLists; ++n) {
|
||
Value * vElem = args[1]->listElems()[n];
|
||
state.callFunction(*args[0], *vElem, lists[n], pos);
|
||
state.forceList(lists[n], lists[n].determinePos(args[0]->determinePos(pos)), "while evaluating the return value of the function passed to builtins.concatMap");
|
||
len += lists[n].listSize();
|
||
}
|
||
|
||
state.mkList(v, len);
|
||
auto out = v.listElems();
|
||
for (unsigned int n = 0, pos = 0; n < nrLists; ++n) {
|
||
auto l = lists[n].listSize();
|
||
if (l)
|
||
memcpy(out + pos, lists[n].listElems(), l * sizeof(Value *));
|
||
pos += l;
|
||
}
|
||
}
|
||
|
||
static RegisterPrimOp primop_concatMap({
|
||
.name = "__concatMap",
|
||
.args = {"f", "list"},
|
||
.doc = R"(
|
||
This function is equivalent to `builtins.concatLists (map f list)`
|
||
but is more efficient.
|
||
)",
|
||
.fun = prim_concatMap,
|
||
});
|
||
|
||
|
||
/*************************************************************
|
||
* Integer arithmetic
|
||
*************************************************************/
|
||
|
||
|
||
static void prim_add(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceValue(*args[0], pos);
|
||
state.forceValue(*args[1], pos);
|
||
if (args[0]->type() == nFloat || args[1]->type() == nFloat)
|
||
v.mkFloat(state.forceFloat(*args[0], pos, "while evaluating the first argument of the addition")
|
||
+ state.forceFloat(*args[1], pos, "while evaluating the second argument of the addition"));
|
||
else
|
||
v.mkInt( state.forceInt(*args[0], pos, "while evaluating the first argument of the addition")
|
||
+ state.forceInt(*args[1], pos, "while evaluating the second argument of the addition"));
|
||
}
|
||
|
||
static RegisterPrimOp primop_add({
|
||
.name = "__add",
|
||
.args = {"e1", "e2"},
|
||
.doc = R"(
|
||
Return the sum of the numbers *e1* and *e2*.
|
||
)",
|
||
.fun = prim_add,
|
||
});
|
||
|
||
static void prim_sub(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceValue(*args[0], pos);
|
||
state.forceValue(*args[1], pos);
|
||
if (args[0]->type() == nFloat || args[1]->type() == nFloat)
|
||
v.mkFloat(state.forceFloat(*args[0], pos, "while evaluating the first argument of the subtraction")
|
||
- state.forceFloat(*args[1], pos, "while evaluating the second argument of the subtraction"));
|
||
else
|
||
v.mkInt( state.forceInt(*args[0], pos, "while evaluating the first argument of the subtraction")
|
||
- state.forceInt(*args[1], pos, "while evaluating the second argument of the subtraction"));
|
||
}
|
||
|
||
static RegisterPrimOp primop_sub({
|
||
.name = "__sub",
|
||
.args = {"e1", "e2"},
|
||
.doc = R"(
|
||
Return the difference between the numbers *e1* and *e2*.
|
||
)",
|
||
.fun = prim_sub,
|
||
});
|
||
|
||
static void prim_mul(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceValue(*args[0], pos);
|
||
state.forceValue(*args[1], pos);
|
||
if (args[0]->type() == nFloat || args[1]->type() == nFloat)
|
||
v.mkFloat(state.forceFloat(*args[0], pos, "while evaluating the first of the multiplication")
|
||
* state.forceFloat(*args[1], pos, "while evaluating the second argument of the multiplication"));
|
||
else
|
||
v.mkInt( state.forceInt(*args[0], pos, "while evaluating the first argument of the multiplication")
|
||
* state.forceInt(*args[1], pos, "while evaluating the second argument of the multiplication"));
|
||
}
|
||
|
||
static RegisterPrimOp primop_mul({
|
||
.name = "__mul",
|
||
.args = {"e1", "e2"},
|
||
.doc = R"(
|
||
Return the product of the numbers *e1* and *e2*.
|
||
)",
|
||
.fun = prim_mul,
|
||
});
|
||
|
||
static void prim_div(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceValue(*args[0], pos);
|
||
state.forceValue(*args[1], pos);
|
||
|
||
NixFloat f2 = state.forceFloat(*args[1], pos, "while evaluating the second operand of the division");
|
||
if (f2 == 0)
|
||
state.debugThrowLastTrace(EvalError({
|
||
.msg = hintfmt("division by zero"),
|
||
.errPos = state.positions[pos]
|
||
}));
|
||
|
||
if (args[0]->type() == nFloat || args[1]->type() == nFloat) {
|
||
v.mkFloat(state.forceFloat(*args[0], pos, "while evaluating the first operand of the division") / f2);
|
||
} else {
|
||
NixInt i1 = state.forceInt(*args[0], pos, "while evaluating the first operand of the division");
|
||
NixInt i2 = state.forceInt(*args[1], pos, "while evaluating the second operand of the division");
|
||
/* Avoid division overflow as it might raise SIGFPE. */
|
||
if (i1 == std::numeric_limits<NixInt>::min() && i2 == -1)
|
||
state.debugThrowLastTrace(EvalError({
|
||
.msg = hintfmt("overflow in integer division"),
|
||
.errPos = state.positions[pos]
|
||
}));
|
||
|
||
v.mkInt(i1 / i2);
|
||
}
|
||
}
|
||
|
||
static RegisterPrimOp primop_div({
|
||
.name = "__div",
|
||
.args = {"e1", "e2"},
|
||
.doc = R"(
|
||
Return the quotient of the numbers *e1* and *e2*.
|
||
)",
|
||
.fun = prim_div,
|
||
});
|
||
|
||
static void prim_bitAnd(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
v.mkInt(state.forceInt(*args[0], pos, "while evaluating the first argument passed to builtins.bitAnd")
|
||
& state.forceInt(*args[1], pos, "while evaluating the second argument passed to builtins.bitAnd"));
|
||
}
|
||
|
||
static RegisterPrimOp primop_bitAnd({
|
||
.name = "__bitAnd",
|
||
.args = {"e1", "e2"},
|
||
.doc = R"(
|
||
Return the bitwise AND of the integers *e1* and *e2*.
|
||
)",
|
||
.fun = prim_bitAnd,
|
||
});
|
||
|
||
static void prim_bitOr(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
v.mkInt(state.forceInt(*args[0], pos, "while evaluating the first argument passed to builtins.bitOr")
|
||
| state.forceInt(*args[1], pos, "while evaluating the second argument passed to builtins.bitOr"));
|
||
}
|
||
|
||
static RegisterPrimOp primop_bitOr({
|
||
.name = "__bitOr",
|
||
.args = {"e1", "e2"},
|
||
.doc = R"(
|
||
Return the bitwise OR of the integers *e1* and *e2*.
|
||
)",
|
||
.fun = prim_bitOr,
|
||
});
|
||
|
||
static void prim_bitXor(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
v.mkInt(state.forceInt(*args[0], pos, "while evaluating the first argument passed to builtins.bitXor")
|
||
^ state.forceInt(*args[1], pos, "while evaluating the second argument passed to builtins.bitXor"));
|
||
}
|
||
|
||
static RegisterPrimOp primop_bitXor({
|
||
.name = "__bitXor",
|
||
.args = {"e1", "e2"},
|
||
.doc = R"(
|
||
Return the bitwise XOR of the integers *e1* and *e2*.
|
||
)",
|
||
.fun = prim_bitXor,
|
||
});
|
||
|
||
static void prim_lessThan(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceValue(*args[0], pos);
|
||
state.forceValue(*args[1], pos);
|
||
// pos is exact here, no need for a message.
|
||
CompareValues comp(state, noPos, "");
|
||
v.mkBool(comp(args[0], args[1]));
|
||
}
|
||
|
||
static RegisterPrimOp primop_lessThan({
|
||
.name = "__lessThan",
|
||
.args = {"e1", "e2"},
|
||
.doc = R"(
|
||
Return `true` if the number *e1* is less than the number *e2*, and
|
||
`false` otherwise. Evaluation aborts if either *e1* or *e2* does not
|
||
evaluate to a number.
|
||
)",
|
||
.fun = prim_lessThan,
|
||
});
|
||
|
||
|
||
/*************************************************************
|
||
* String manipulation
|
||
*************************************************************/
|
||
|
||
|
||
/* Convert the argument to a string. Paths are *not* copied to the
|
||
store, so `toString /foo/bar' yields `"/foo/bar"', not
|
||
`"/nix/store/whatever..."'. */
|
||
static void prim_toString(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
NixStringContext context;
|
||
auto s = state.coerceToString(pos, *args[0], context,
|
||
"while evaluating the first argument passed to builtins.toString",
|
||
true, false);
|
||
v.mkString(*s, context);
|
||
}
|
||
|
||
static RegisterPrimOp primop_toString({
|
||
.name = "toString",
|
||
.args = {"e"},
|
||
.doc = R"(
|
||
Convert the expression *e* to a string. *e* can be:
|
||
|
||
- A string (in which case the string is returned unmodified).
|
||
|
||
- A path (e.g., `toString /foo/bar` yields `"/foo/bar"`.
|
||
|
||
- A set containing `{ __toString = self: ...; }` or `{ outPath = ...; }`.
|
||
|
||
- An integer.
|
||
|
||
- A list, in which case the string representations of its elements
|
||
are joined with spaces.
|
||
|
||
- A Boolean (`false` yields `""`, `true` yields `"1"`).
|
||
|
||
- `null`, which yields the empty string.
|
||
)",
|
||
.fun = prim_toString,
|
||
});
|
||
|
||
/* `substring start len str' returns the substring of `str' starting
|
||
at character position `min(start, stringLength str)' inclusive and
|
||
ending at `min(start + len, stringLength str)'. `start' must be
|
||
non-negative. */
|
||
static void prim_substring(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
int start = state.forceInt(*args[0], pos, "while evaluating the first argument (the start offset) passed to builtins.substring");
|
||
|
||
if (start < 0)
|
||
state.debugThrowLastTrace(EvalError({
|
||
.msg = hintfmt("negative start position in 'substring'"),
|
||
.errPos = state.positions[pos]
|
||
}));
|
||
|
||
|
||
int len = state.forceInt(*args[1], pos, "while evaluating the second argument (the substring length) passed to builtins.substring");
|
||
|
||
// Special-case on empty substring to avoid O(n) strlen
|
||
// This allows for the use of empty substrings to efficently capture string context
|
||
if (len == 0) {
|
||
state.forceValue(*args[2], pos);
|
||
if (args[2]->type() == nString) {
|
||
v.mkString("", args[2]->context());
|
||
return;
|
||
}
|
||
}
|
||
|
||
NixStringContext context;
|
||
auto s = state.coerceToString(pos, *args[2], context, "while evaluating the third argument (the string) passed to builtins.substring");
|
||
|
||
v.mkString((unsigned int) start >= s->size() ? "" : s->substr(start, len), context);
|
||
}
|
||
|
||
static RegisterPrimOp primop_substring({
|
||
.name = "__substring",
|
||
.args = {"start", "len", "s"},
|
||
.doc = R"(
|
||
Return the substring of *s* from character position *start*
|
||
(zero-based) up to but not including *start + len*. If *start* is
|
||
greater than the length of the string, an empty string is returned.
|
||
If *start + len* lies beyond the end of the string or *len* is `-1`,
|
||
only the substring up to the end of the string is returned.
|
||
*start* must be non-negative.
|
||
For example,
|
||
|
||
```nix
|
||
builtins.substring 0 3 "nixos"
|
||
```
|
||
|
||
evaluates to `"nix"`.
|
||
)",
|
||
.fun = prim_substring,
|
||
});
|
||
|
||
static void prim_stringLength(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
NixStringContext context;
|
||
auto s = state.coerceToString(pos, *args[0], context, "while evaluating the argument passed to builtins.stringLength");
|
||
v.mkInt(s->size());
|
||
}
|
||
|
||
static RegisterPrimOp primop_stringLength({
|
||
.name = "__stringLength",
|
||
.args = {"e"},
|
||
.doc = R"(
|
||
Return the length of the string *e*. If *e* is not a string,
|
||
evaluation is aborted.
|
||
)",
|
||
.fun = prim_stringLength,
|
||
});
|
||
|
||
/* Return the cryptographic hash of a string in base-16. */
|
||
static void prim_hashString(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
auto algo = state.forceStringNoCtx(*args[0], pos, "while evaluating the first argument passed to builtins.hashString");
|
||
std::optional<HashAlgorithm> ha = parseHashAlgo(algo);
|
||
if (!ha)
|
||
state.debugThrowLastTrace(Error({
|
||
.msg = hintfmt("unknown hash algo '%1%'", algo),
|
||
.errPos = state.positions[pos]
|
||
}));
|
||
|
||
NixStringContext context; // discarded
|
||
auto s = state.forceString(*args[1], context, pos, "while evaluating the second argument passed to builtins.hashString");
|
||
|
||
v.mkString(hashString(*ha, s).to_string(HashFormat::Base16, false));
|
||
}
|
||
|
||
static RegisterPrimOp primop_hashString({
|
||
.name = "__hashString",
|
||
.args = {"type", "s"},
|
||
.doc = R"(
|
||
Return a base-16 representation of the cryptographic hash of string
|
||
*s*. The hash algorithm specified by *type* must be one of `"md5"`,
|
||
`"sha1"`, `"sha256"` or `"sha512"`.
|
||
)",
|
||
.fun = prim_hashString,
|
||
});
|
||
|
||
static void prim_convertHash(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceAttrs(*args[0], pos, "while evaluating the first argument passed to builtins.convertHash");
|
||
auto &inputAttrs = args[0]->attrs;
|
||
|
||
Bindings::iterator iteratorHash = getAttr(state, state.symbols.create("hash"), inputAttrs, "while locating the attribute 'hash'");
|
||
auto hash = state.forceStringNoCtx(*iteratorHash->value, pos, "while evaluating the attribute 'hash'");
|
||
|
||
Bindings::iterator iteratorHashAlgo = inputAttrs->find(state.symbols.create("hashAlgo"));
|
||
std::optional<HashAlgorithm> ha = std::nullopt;
|
||
if (iteratorHashAlgo != inputAttrs->end()) {
|
||
ha = parseHashAlgo(state.forceStringNoCtx(*iteratorHashAlgo->value, pos, "while evaluating the attribute 'hashAlgo'"));
|
||
}
|
||
|
||
Bindings::iterator iteratorToHashFormat = getAttr(state, state.symbols.create("toHashFormat"), args[0]->attrs, "while locating the attribute 'toHashFormat'");
|
||
HashFormat hf = parseHashFormat(state.forceStringNoCtx(*iteratorToHashFormat->value, pos, "while evaluating the attribute 'toHashFormat'"));
|
||
|
||
v.mkString(Hash::parseAny(hash, ha).to_string(hf, hf == HashFormat::SRI));
|
||
}
|
||
|
||
static RegisterPrimOp primop_convertHash({
|
||
.name = "__convertHash",
|
||
.args = {"args"},
|
||
.doc = R"(
|
||
Return the specified representation of a hash string, based on the attributes presented in *args*:
|
||
|
||
- `hash`
|
||
|
||
The hash to be converted.
|
||
The hash format is detected automatically.
|
||
|
||
- `hashAlgo`
|
||
|
||
The algorithm used to create the hash. Must be one of
|
||
- `"md5"`
|
||
- `"sha1"`
|
||
- `"sha256"`
|
||
- `"sha512"`
|
||
|
||
The attribute may be omitted when `hash` is an [SRI hash](https://www.w3.org/TR/SRI/#the-integrity-attribute) or when the hash is prefixed with the hash algorithm name followed by a colon.
|
||
That `<hashAlgo>:<hashBody>` syntax is supported for backwards compatibility with existing tooling.
|
||
|
||
- `toHashFormat`
|
||
|
||
The format of the resulting hash. Must be one of
|
||
- `"base16"`
|
||
- `"nix32"`
|
||
- `"base32"` (deprecated alias for `"nix32"`)
|
||
- `"base64"`
|
||
- `"sri"`
|
||
|
||
The result hash is the *toHashFormat* representation of the hash *hash*.
|
||
|
||
> **Example**
|
||
>
|
||
> Convert a SHA256 hash in Base16 to SRI:
|
||
>
|
||
> ```nix
|
||
> builtins.convertHash {
|
||
> hash = "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855";
|
||
> toHashFormat = "sri";
|
||
> hashAlgo = "sha256";
|
||
> }
|
||
> ```
|
||
>
|
||
> "sha256-47DEQpj8HBSa+/TImW+5JCeuQeRkm5NMpJWZG3hSuFU="
|
||
|
||
> **Example**
|
||
>
|
||
> Convert a SHA256 hash in SRI to Base16:
|
||
>
|
||
> ```nix
|
||
> builtins.convertHash {
|
||
> hash = "sha256-47DEQpj8HBSa+/TImW+5JCeuQeRkm5NMpJWZG3hSuFU=";
|
||
> toHashFormat = "base16";
|
||
> }
|
||
> ```
|
||
>
|
||
> "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855"
|
||
|
||
> **Example**
|
||
>
|
||
> Convert a hash in the form `<hashAlgo>:<hashBody>` in Base16 to SRI:
|
||
>
|
||
> ```nix
|
||
> builtins.convertHash {
|
||
> hash = "sha256:e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855";
|
||
> toHashFormat = "sri";
|
||
> }
|
||
> ```
|
||
>
|
||
> "sha256-47DEQpj8HBSa+/TImW+5JCeuQeRkm5NMpJWZG3hSuFU="
|
||
)",
|
||
.fun = prim_convertHash,
|
||
});
|
||
|
||
struct RegexCache
|
||
{
|
||
// TODO use C++20 transparent comparison when available
|
||
std::unordered_map<std::string_view, std::regex> cache;
|
||
std::list<std::string> keys;
|
||
|
||
std::regex get(std::string_view re)
|
||
{
|
||
auto it = cache.find(re);
|
||
if (it != cache.end())
|
||
return it->second;
|
||
keys.emplace_back(re);
|
||
return cache.emplace(keys.back(), std::regex(keys.back(), std::regex::extended)).first->second;
|
||
}
|
||
};
|
||
|
||
std::shared_ptr<RegexCache> makeRegexCache()
|
||
{
|
||
return std::make_shared<RegexCache>();
|
||
}
|
||
|
||
void prim_match(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
auto re = state.forceStringNoCtx(*args[0], pos, "while evaluating the first argument passed to builtins.match");
|
||
|
||
try {
|
||
|
||
auto regex = state.regexCache->get(re);
|
||
|
||
NixStringContext context;
|
||
const auto str = state.forceString(*args[1], context, pos, "while evaluating the second argument passed to builtins.match");
|
||
|
||
std::cmatch match;
|
||
if (!std::regex_match(str.begin(), str.end(), match, regex)) {
|
||
v.mkNull();
|
||
return;
|
||
}
|
||
|
||
// the first match is the whole string
|
||
const size_t len = match.size() - 1;
|
||
state.mkList(v, len);
|
||
for (size_t i = 0; i < len; ++i) {
|
||
if (!match[i+1].matched)
|
||
(v.listElems()[i] = state.allocValue())->mkNull();
|
||
else
|
||
(v.listElems()[i] = state.allocValue())->mkString(match[i + 1].str());
|
||
}
|
||
|
||
} catch (std::regex_error & e) {
|
||
if (e.code() == std::regex_constants::error_space) {
|
||
// limit is _GLIBCXX_REGEX_STATE_LIMIT for libstdc++
|
||
state.debugThrowLastTrace(EvalError({
|
||
.msg = hintfmt("memory limit exceeded by regular expression '%s'", re),
|
||
.errPos = state.positions[pos]
|
||
}));
|
||
} else
|
||
state.debugThrowLastTrace(EvalError({
|
||
.msg = hintfmt("invalid regular expression '%s'", re),
|
||
.errPos = state.positions[pos]
|
||
}));
|
||
}
|
||
}
|
||
|
||
static RegisterPrimOp primop_match({
|
||
.name = "__match",
|
||
.args = {"regex", "str"},
|
||
.doc = R"s(
|
||
Returns a list if the [extended POSIX regular
|
||
expression](http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap09.html#tag_09_04)
|
||
*regex* matches *str* precisely, otherwise returns `null`. Each item
|
||
in the list is a regex group.
|
||
|
||
```nix
|
||
builtins.match "ab" "abc"
|
||
```
|
||
|
||
Evaluates to `null`.
|
||
|
||
```nix
|
||
builtins.match "abc" "abc"
|
||
```
|
||
|
||
Evaluates to `[ ]`.
|
||
|
||
```nix
|
||
builtins.match "a(b)(c)" "abc"
|
||
```
|
||
|
||
Evaluates to `[ "b" "c" ]`.
|
||
|
||
```nix
|
||
builtins.match "[[:space:]]+([[:upper:]]+)[[:space:]]+" " FOO "
|
||
```
|
||
|
||
Evaluates to `[ "FOO" ]`.
|
||
)s",
|
||
.fun = prim_match,
|
||
});
|
||
|
||
/* Split a string with a regular expression, and return a list of the
|
||
non-matching parts interleaved by the lists of the matching groups. */
|
||
void prim_split(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
auto re = state.forceStringNoCtx(*args[0], pos, "while evaluating the first argument passed to builtins.split");
|
||
|
||
try {
|
||
|
||
auto regex = state.regexCache->get(re);
|
||
|
||
NixStringContext context;
|
||
const auto str = state.forceString(*args[1], context, pos, "while evaluating the second argument passed to builtins.split");
|
||
|
||
auto begin = std::cregex_iterator(str.begin(), str.end(), regex);
|
||
auto end = std::cregex_iterator();
|
||
|
||
// Any matches results are surrounded by non-matching results.
|
||
const size_t len = std::distance(begin, end);
|
||
state.mkList(v, 2 * len + 1);
|
||
size_t idx = 0;
|
||
|
||
if (len == 0) {
|
||
v.listElems()[idx++] = args[1];
|
||
return;
|
||
}
|
||
|
||
for (auto i = begin; i != end; ++i) {
|
||
assert(idx <= 2 * len + 1 - 3);
|
||
auto match = *i;
|
||
|
||
// Add a string for non-matched characters.
|
||
(v.listElems()[idx++] = state.allocValue())->mkString(match.prefix().str());
|
||
|
||
// Add a list for matched substrings.
|
||
const size_t slen = match.size() - 1;
|
||
auto elem = v.listElems()[idx++] = state.allocValue();
|
||
|
||
// Start at 1, beacause the first match is the whole string.
|
||
state.mkList(*elem, slen);
|
||
for (size_t si = 0; si < slen; ++si) {
|
||
if (!match[si + 1].matched)
|
||
(elem->listElems()[si] = state.allocValue())->mkNull();
|
||
else
|
||
(elem->listElems()[si] = state.allocValue())->mkString(match[si + 1].str());
|
||
}
|
||
|
||
// Add a string for non-matched suffix characters.
|
||
if (idx == 2 * len)
|
||
(v.listElems()[idx++] = state.allocValue())->mkString(match.suffix().str());
|
||
}
|
||
|
||
assert(idx == 2 * len + 1);
|
||
|
||
} catch (std::regex_error & e) {
|
||
if (e.code() == std::regex_constants::error_space) {
|
||
// limit is _GLIBCXX_REGEX_STATE_LIMIT for libstdc++
|
||
state.debugThrowLastTrace(EvalError({
|
||
.msg = hintfmt("memory limit exceeded by regular expression '%s'", re),
|
||
.errPos = state.positions[pos]
|
||
}));
|
||
} else
|
||
state.debugThrowLastTrace(EvalError({
|
||
.msg = hintfmt("invalid regular expression '%s'", re),
|
||
.errPos = state.positions[pos]
|
||
}));
|
||
}
|
||
}
|
||
|
||
static RegisterPrimOp primop_split({
|
||
.name = "__split",
|
||
.args = {"regex", "str"},
|
||
.doc = R"s(
|
||
Returns a list composed of non matched strings interleaved with the
|
||
lists of the [extended POSIX regular
|
||
expression](http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap09.html#tag_09_04)
|
||
*regex* matches of *str*. Each item in the lists of matched
|
||
sequences is a regex group.
|
||
|
||
```nix
|
||
builtins.split "(a)b" "abc"
|
||
```
|
||
|
||
Evaluates to `[ "" [ "a" ] "c" ]`.
|
||
|
||
```nix
|
||
builtins.split "([ac])" "abc"
|
||
```
|
||
|
||
Evaluates to `[ "" [ "a" ] "b" [ "c" ] "" ]`.
|
||
|
||
```nix
|
||
builtins.split "(a)|(c)" "abc"
|
||
```
|
||
|
||
Evaluates to `[ "" [ "a" null ] "b" [ null "c" ] "" ]`.
|
||
|
||
```nix
|
||
builtins.split "([[:upper:]]+)" " FOO "
|
||
```
|
||
|
||
Evaluates to `[ " " [ "FOO" ] " " ]`.
|
||
)s",
|
||
.fun = prim_split,
|
||
});
|
||
|
||
static void prim_concatStringsSep(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
NixStringContext context;
|
||
|
||
auto sep = state.forceString(*args[0], context, pos, "while evaluating the first argument (the separator string) passed to builtins.concatStringsSep");
|
||
state.forceList(*args[1], pos, "while evaluating the second argument (the list of strings to concat) passed to builtins.concatStringsSep");
|
||
|
||
std::string res;
|
||
res.reserve((args[1]->listSize() + 32) * sep.size());
|
||
bool first = true;
|
||
|
||
for (auto elem : args[1]->listItems()) {
|
||
if (first) first = false; else res += sep;
|
||
res += *state.coerceToString(pos, *elem, context, "while evaluating one element of the list of strings to concat passed to builtins.concatStringsSep");
|
||
}
|
||
|
||
v.mkString(res, context);
|
||
}
|
||
|
||
static RegisterPrimOp primop_concatStringsSep({
|
||
.name = "__concatStringsSep",
|
||
.args = {"separator", "list"},
|
||
.doc = R"(
|
||
Concatenate a list of strings with a separator between each
|
||
element, e.g. `concatStringsSep "/" ["usr" "local" "bin"] ==
|
||
"usr/local/bin"`.
|
||
)",
|
||
.fun = prim_concatStringsSep,
|
||
});
|
||
|
||
static void prim_replaceStrings(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
state.forceList(*args[0], pos, "while evaluating the first argument passed to builtins.replaceStrings");
|
||
state.forceList(*args[1], pos, "while evaluating the second argument passed to builtins.replaceStrings");
|
||
if (args[0]->listSize() != args[1]->listSize())
|
||
state.error("'from' and 'to' arguments passed to builtins.replaceStrings have different lengths").atPos(pos).debugThrow<EvalError>();
|
||
|
||
std::vector<std::string> from;
|
||
from.reserve(args[0]->listSize());
|
||
for (auto elem : args[0]->listItems())
|
||
from.emplace_back(state.forceString(*elem, pos, "while evaluating one of the strings to replace passed to builtins.replaceStrings"));
|
||
|
||
std::unordered_map<size_t, std::string> cache;
|
||
auto to = args[1]->listItems();
|
||
|
||
NixStringContext context;
|
||
auto s = state.forceString(*args[2], context, pos, "while evaluating the third argument passed to builtins.replaceStrings");
|
||
|
||
std::string res;
|
||
// Loops one past last character to handle the case where 'from' contains an empty string.
|
||
for (size_t p = 0; p <= s.size(); ) {
|
||
bool found = false;
|
||
auto i = from.begin();
|
||
auto j = to.begin();
|
||
size_t j_index = 0;
|
||
for (; i != from.end(); ++i, ++j, ++j_index)
|
||
if (s.compare(p, i->size(), *i) == 0) {
|
||
found = true;
|
||
auto v = cache.find(j_index);
|
||
if (v == cache.end()) {
|
||
NixStringContext ctx;
|
||
auto ts = state.forceString(**j, ctx, pos, "while evaluating one of the replacement strings passed to builtins.replaceStrings");
|
||
v = (cache.emplace(j_index, ts)).first;
|
||
for (auto& path : ctx)
|
||
context.insert(path);
|
||
}
|
||
res += v->second;
|
||
if (i->empty()) {
|
||
if (p < s.size())
|
||
res += s[p];
|
||
p++;
|
||
} else {
|
||
p += i->size();
|
||
}
|
||
break;
|
||
}
|
||
if (!found) {
|
||
if (p < s.size())
|
||
res += s[p];
|
||
p++;
|
||
}
|
||
}
|
||
|
||
v.mkString(res, context);
|
||
}
|
||
|
||
static RegisterPrimOp primop_replaceStrings({
|
||
.name = "__replaceStrings",
|
||
.args = {"from", "to", "s"},
|
||
.doc = R"(
|
||
Given string *s*, replace every occurrence of the strings in *from*
|
||
with the corresponding string in *to*.
|
||
|
||
The argument *to* is lazy, that is, it is only evaluated when its corresponding pattern in *from* is matched in the string *s*
|
||
|
||
Example:
|
||
|
||
```nix
|
||
builtins.replaceStrings ["oo" "a"] ["a" "i"] "foobar"
|
||
```
|
||
|
||
evaluates to `"fabir"`.
|
||
)",
|
||
.fun = prim_replaceStrings,
|
||
});
|
||
|
||
|
||
/*************************************************************
|
||
* Versions
|
||
*************************************************************/
|
||
|
||
|
||
static void prim_parseDrvName(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
auto name = state.forceStringNoCtx(*args[0], pos, "while evaluating the first argument passed to builtins.parseDrvName");
|
||
DrvName parsed(name);
|
||
auto attrs = state.buildBindings(2);
|
||
attrs.alloc(state.sName).mkString(parsed.name);
|
||
attrs.alloc("version").mkString(parsed.version);
|
||
v.mkAttrs(attrs);
|
||
}
|
||
|
||
static RegisterPrimOp primop_parseDrvName({
|
||
.name = "__parseDrvName",
|
||
.args = {"s"},
|
||
.doc = R"(
|
||
Split the string *s* into a package name and version. The package
|
||
name is everything up to but not including the first dash not followed
|
||
by a letter, and the version is everything following that dash. The
|
||
result is returned in a set `{ name, version }`. Thus,
|
||
`builtins.parseDrvName "nix-0.12pre12876"` returns `{ name =
|
||
"nix"; version = "0.12pre12876"; }`.
|
||
)",
|
||
.fun = prim_parseDrvName,
|
||
});
|
||
|
||
static void prim_compareVersions(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
auto version1 = state.forceStringNoCtx(*args[0], pos, "while evaluating the first argument passed to builtins.compareVersions");
|
||
auto version2 = state.forceStringNoCtx(*args[1], pos, "while evaluating the second argument passed to builtins.compareVersions");
|
||
v.mkInt(compareVersions(version1, version2));
|
||
}
|
||
|
||
static RegisterPrimOp primop_compareVersions({
|
||
.name = "__compareVersions",
|
||
.args = {"s1", "s2"},
|
||
.doc = R"(
|
||
Compare two strings representing versions and return `-1` if
|
||
version *s1* is older than version *s2*, `0` if they are the same,
|
||
and `1` if *s1* is newer than *s2*. The version comparison
|
||
algorithm is the same as the one used by [`nix-env
|
||
-u`](../command-ref/nix-env.md#operation---upgrade).
|
||
)",
|
||
.fun = prim_compareVersions,
|
||
});
|
||
|
||
static void prim_splitVersion(EvalState & state, const PosIdx pos, Value * * args, Value & v)
|
||
{
|
||
auto version = state.forceStringNoCtx(*args[0], pos, "while evaluating the first argument passed to builtins.splitVersion");
|
||
auto iter = version.cbegin();
|
||
Strings components;
|
||
while (iter != version.cend()) {
|
||
auto component = nextComponent(iter, version.cend());
|
||
if (component.empty())
|
||
break;
|
||
components.emplace_back(component);
|
||
}
|
||
state.mkList(v, components.size());
|
||
for (const auto & [n, component] : enumerate(components))
|
||
(v.listElems()[n] = state.allocValue())->mkString(std::move(component));
|
||
}
|
||
|
||
static RegisterPrimOp primop_splitVersion({
|
||
.name = "__splitVersion",
|
||
.args = {"s"},
|
||
.doc = R"(
|
||
Split a string representing a version into its components, by the
|
||
same version splitting logic underlying the version comparison in
|
||
[`nix-env -u`](../command-ref/nix-env.md#operation---upgrade).
|
||
)",
|
||
.fun = prim_splitVersion,
|
||
});
|
||
|
||
|
||
/*************************************************************
|
||
* Primop registration
|
||
*************************************************************/
|
||
|
||
|
||
RegisterPrimOp::PrimOps * RegisterPrimOp::primOps;
|
||
|
||
|
||
RegisterPrimOp::RegisterPrimOp(PrimOp && primOp)
|
||
{
|
||
if (!primOps) primOps = new PrimOps;
|
||
primOps->push_back(std::move(primOp));
|
||
}
|
||
|
||
|
||
void EvalState::createBaseEnv()
|
||
{
|
||
baseEnv.up = 0;
|
||
|
||
/* Add global constants such as `true' to the base environment. */
|
||
Value v;
|
||
|
||
/* `builtins' must be first! */
|
||
v.mkAttrs(buildBindings(128).finish());
|
||
addConstant("builtins", v, {
|
||
.type = nAttrs,
|
||
.doc = R"(
|
||
Contains all the [built-in functions](@docroot@/language/builtins.md) and values.
|
||
|
||
Since built-in functions were added over time, [testing for attributes](./operators.md#has-attribute) in `builtins` can be used for graceful fallback on older Nix installations:
|
||
|
||
```nix
|
||
# if hasContext is not available, we assume `s` has a context
|
||
if builtins ? hasContext then builtins.hasContext s else true
|
||
```
|
||
)",
|
||
});
|
||
|
||
v.mkBool(true);
|
||
addConstant("true", v, {
|
||
.type = nBool,
|
||
.doc = R"(
|
||
Primitive value.
|
||
|
||
It can be returned by
|
||
[comparison operators](@docroot@/language/operators.md#Comparison)
|
||
and used in
|
||
[conditional expressions](@docroot@/language/constructs.md#Conditionals).
|
||
|
||
The name `true` is not special, and can be shadowed:
|
||
|
||
```nix-repl
|
||
nix-repl> let true = 1; in true
|
||
1
|
||
```
|
||
)",
|
||
});
|
||
|
||
v.mkBool(false);
|
||
addConstant("false", v, {
|
||
.type = nBool,
|
||
.doc = R"(
|
||
Primitive value.
|
||
|
||
It can be returned by
|
||
[comparison operators](@docroot@/language/operators.md#Comparison)
|
||
and used in
|
||
[conditional expressions](@docroot@/language/constructs.md#Conditionals).
|
||
|
||
The name `false` is not special, and can be shadowed:
|
||
|
||
```nix-repl
|
||
nix-repl> let false = 1; in false
|
||
1
|
||
```
|
||
)",
|
||
});
|
||
|
||
v.mkNull();
|
||
addConstant("null", v, {
|
||
.type = nNull,
|
||
.doc = R"(
|
||
Primitive value.
|
||
|
||
The name `null` is not special, and can be shadowed:
|
||
|
||
```nix-repl
|
||
nix-repl> let null = 1; in null
|
||
1
|
||
```
|
||
)",
|
||
});
|
||
|
||
if (!evalSettings.pureEval) {
|
||
v.mkInt(time(0));
|
||
}
|
||
addConstant("__currentTime", v, {
|
||
.type = nInt,
|
||
.doc = R"(
|
||
Return the [Unix time](https://en.wikipedia.org/wiki/Unix_time) at first evaluation.
|
||
Repeated references to that name will re-use the initially obtained value.
|
||
|
||
Example:
|
||
|
||
```console
|
||
$ nix repl
|
||
Welcome to Nix 2.15.1 Type :? for help.
|
||
|
||
nix-repl> builtins.currentTime
|
||
1683705525
|
||
|
||
nix-repl> builtins.currentTime
|
||
1683705525
|
||
```
|
||
|
||
The [store path](@docroot@/glossary.md#gloss-store-path) of a derivation depending on `currentTime` will differ for each evaluation, unless both evaluate `builtins.currentTime` in the same second.
|
||
)",
|
||
.impureOnly = true,
|
||
});
|
||
|
||
if (!evalSettings.pureEval)
|
||
v.mkString(evalSettings.getCurrentSystem());
|
||
addConstant("__currentSystem", v, {
|
||
.type = nString,
|
||
.doc = R"(
|
||
The value of the
|
||
[`eval-system`](@docroot@/command-ref/conf-file.md#conf-eval-system)
|
||
or else
|
||
[`system`](@docroot@/command-ref/conf-file.md#conf-system)
|
||
configuration option.
|
||
|
||
It can be used to set the `system` attribute for [`builtins.derivation`](@docroot@/language/derivations.md) such that the resulting derivation can be built on the same system that evaluates the Nix expression:
|
||
|
||
```nix
|
||
builtins.derivation {
|
||
# ...
|
||
system = builtins.currentSystem;
|
||
}
|
||
```
|
||
|
||
It can be overridden in order to create derivations for different system than the current one:
|
||
|
||
```console
|
||
$ nix-instantiate --system "mips64-linux" --eval --expr 'builtins.currentSystem'
|
||
"mips64-linux"
|
||
```
|
||
)",
|
||
.impureOnly = true,
|
||
});
|
||
|
||
v.mkString(nixVersion);
|
||
addConstant("__nixVersion", v, {
|
||
.type = nString,
|
||
.doc = R"(
|
||
The version of Nix.
|
||
|
||
For example, where the command line returns the current Nix version,
|
||
|
||
```shell-session
|
||
$ nix --version
|
||
nix (Nix) 2.16.0
|
||
```
|
||
|
||
the Nix language evaluator returns the same value:
|
||
|
||
```nix-repl
|
||
nix-repl> builtins.nixVersion
|
||
"2.16.0"
|
||
```
|
||
)",
|
||
});
|
||
|
||
v.mkString(store->storeDir);
|
||
addConstant("__storeDir", v, {
|
||
.type = nString,
|
||
.doc = R"(
|
||
Logical file system location of the [Nix store](@docroot@/glossary.md#gloss-store) currently in use.
|
||
|
||
This value is determined by the `store` parameter in [Store URLs](@docroot@/store/types/index.md#store-url-format):
|
||
|
||
```shell-session
|
||
$ nix-instantiate --store 'dummy://?store=/blah' --eval --expr builtins.storeDir
|
||
"/blah"
|
||
```
|
||
)",
|
||
});
|
||
|
||
/* Language version. This should be increased every time a new
|
||
language feature gets added. It's not necessary to increase it
|
||
when primops get added, because you can just use `builtins ?
|
||
primOp' to check. */
|
||
v.mkInt(6);
|
||
addConstant("__langVersion", v, {
|
||
.type = nInt,
|
||
.doc = R"(
|
||
The current version of the Nix language.
|
||
)",
|
||
});
|
||
|
||
// Miscellaneous
|
||
if (evalSettings.enableNativeCode) {
|
||
addPrimOp({
|
||
.name = "__importNative",
|
||
.arity = 2,
|
||
.fun = prim_importNative,
|
||
});
|
||
addPrimOp({
|
||
.name = "__exec",
|
||
.arity = 1,
|
||
.fun = prim_exec,
|
||
});
|
||
}
|
||
|
||
addPrimOp({
|
||
.name = "__traceVerbose",
|
||
.args = { "e1", "e2" },
|
||
.arity = 2,
|
||
.doc = R"(
|
||
Evaluate *e1* and print its abstract syntax representation on standard
|
||
error if `--trace-verbose` is enabled. Then return *e2*. This function
|
||
is useful for debugging.
|
||
)",
|
||
.fun = evalSettings.traceVerbose ? prim_trace : prim_second,
|
||
});
|
||
|
||
/* Add a value containing the current Nix expression search path. */
|
||
mkList(v, searchPath.elements.size());
|
||
int n = 0;
|
||
for (auto & i : searchPath.elements) {
|
||
auto attrs = buildBindings(2);
|
||
attrs.alloc("path").mkString(i.path.s);
|
||
attrs.alloc("prefix").mkString(i.prefix.s);
|
||
(v.listElems()[n++] = allocValue())->mkAttrs(attrs);
|
||
}
|
||
addConstant("__nixPath", v, {
|
||
.type = nList,
|
||
.doc = R"(
|
||
List of search path entries used to resolve [lookup paths](@docroot@/language/constructs/lookup-path.md).
|
||
|
||
Lookup path expressions can be
|
||
[desugared](https://en.wikipedia.org/wiki/Syntactic_sugar)
|
||
using this and
|
||
[`builtins.findFile`](./builtins.html#builtins-findFile):
|
||
|
||
```nix
|
||
<nixpkgs>
|
||
```
|
||
|
||
is equivalent to:
|
||
|
||
```nix
|
||
builtins.findFile builtins.nixPath "nixpkgs"
|
||
```
|
||
)",
|
||
});
|
||
|
||
if (RegisterPrimOp::primOps)
|
||
for (auto & primOp : *RegisterPrimOp::primOps)
|
||
if (experimentalFeatureSettings.isEnabled(primOp.experimentalFeature))
|
||
{
|
||
auto primOpAdjusted = primOp;
|
||
primOpAdjusted.arity = std::max(primOp.args.size(), primOp.arity);
|
||
addPrimOp(std::move(primOpAdjusted));
|
||
}
|
||
|
||
/* Add a wrapper around the derivation primop that computes the
|
||
`drvPath' and `outPath' attributes lazily.
|
||
|
||
Null docs because it is documented separately.
|
||
*/
|
||
auto vDerivation = allocValue();
|
||
addConstant("derivation", vDerivation, {
|
||
.type = nFunction,
|
||
});
|
||
|
||
/* Now that we've added all primops, sort the `builtins' set,
|
||
because attribute lookups expect it to be sorted. */
|
||
baseEnv.values[0]->attrs->sort();
|
||
|
||
staticBaseEnv->sort();
|
||
|
||
/* Note: we have to initialize the 'derivation' constant *after*
|
||
building baseEnv/staticBaseEnv because it uses 'builtins'. */
|
||
evalFile(derivationInternal, *vDerivation);
|
||
}
|
||
|
||
|
||
}
|