143 lines
4.2 KiB
C++
143 lines
4.2 KiB
C++
#include "attr-path.hh"
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#include "eval-inline.hh"
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namespace nix {
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static Strings parseAttrPath(std::string_view s)
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{
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Strings res;
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std::string cur;
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auto i = s.begin();
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while (i != s.end()) {
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if (*i == '.') {
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res.push_back(cur);
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cur.clear();
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} else if (*i == '"') {
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++i;
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while (1) {
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if (i == s.end())
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throw ParseError("missing closing quote in selection path '%1%'", s);
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if (*i == '"') break;
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cur.push_back(*i++);
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}
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} else
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cur.push_back(*i);
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++i;
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}
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if (!cur.empty()) res.push_back(cur);
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return res;
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}
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std::vector<Symbol> parseAttrPath(EvalState & state, std::string_view s)
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{
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std::vector<Symbol> res;
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for (auto & a : parseAttrPath(s))
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res.push_back(state.symbols.create(a));
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return res;
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}
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std::pair<Value *, PosIdx> findAlongAttrPath(EvalState & state, const std::string & attrPath,
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Bindings & autoArgs, Value & vIn)
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{
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Strings tokens = parseAttrPath(attrPath);
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Value * v = &vIn;
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PosIdx pos = noPos;
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for (auto & attr : tokens) {
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/* Is i an index (integer) or a normal attribute name? */
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auto attrIndex = string2Int<unsigned int>(attr);
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/* Evaluate the expression. */
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Value * vNew = state.allocValue();
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state.autoCallFunction(autoArgs, *v, *vNew);
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v = vNew;
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state.forceValue(*v, noPos);
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/* It should evaluate to either a set or an expression,
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according to what is specified in the attrPath. */
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if (!attrIndex) {
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if (v->type() != nAttrs)
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throw TypeError(
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"the expression selected by the selection path '%1%' should be a set but is %2%",
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attrPath,
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showType(*v));
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if (attr.empty())
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throw Error("empty attribute name in selection path '%1%'", attrPath);
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Bindings::iterator a = v->attrs->find(state.symbols.create(attr));
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if (a == v->attrs->end()) {
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std::set<std::string> attrNames;
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for (auto & attr : *v->attrs)
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attrNames.insert(state.symbols[attr.name]);
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auto suggestions = Suggestions::bestMatches(attrNames, attr);
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throw AttrPathNotFound(suggestions, "attribute '%1%' in selection path '%2%' not found", attr, attrPath);
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}
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v = &*a->value;
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pos = a->pos;
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}
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else {
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if (!v->isList())
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throw TypeError(
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"the expression selected by the selection path '%1%' should be a list but is %2%",
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attrPath,
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showType(*v));
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if (*attrIndex >= v->listSize())
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throw AttrPathNotFound("list index %1% in selection path '%2%' is out of range", *attrIndex, attrPath);
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v = v->listElems()[*attrIndex];
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pos = noPos;
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}
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}
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return {v, pos};
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}
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std::pair<SourcePath, uint32_t> findPackageFilename(EvalState & state, Value & v, std::string what)
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{
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Value * v2;
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try {
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auto dummyArgs = state.allocBindings(0);
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v2 = findAlongAttrPath(state, "meta.position", *dummyArgs, v).first;
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} catch (Error &) {
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throw NoPositionInfo("package '%s' has no source location information", what);
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}
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// FIXME: is it possible to extract the Pos object instead of doing this
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// toString + parsing?
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NixStringContext context;
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auto path = state.coerceToPath(noPos, *v2, context, "while evaluating the 'meta.position' attribute of a derivation");
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auto fn = path.path.abs();
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auto fail = [fn]() {
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throw ParseError("cannot parse 'meta.position' attribute '%s'", fn);
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};
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try {
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auto colon = fn.rfind(':');
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if (colon == std::string::npos) fail();
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std::string filename(fn, 0, colon);
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auto lineno = std::stoi(std::string(fn, colon + 1, std::string::npos));
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return {SourcePath{path.accessor, CanonPath(fn.substr(0, colon))}, lineno};
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} catch (std::invalid_argument & e) {
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fail();
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abort();
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}
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}
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}
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