Nix/src/libexpr/primops/fetchMercurial.cc
Eelco Dolstra 462421d345 Backport libfetchers from the flakes branch
This provides a pluggable mechanism for defining new fetchers. It adds
a builtin function 'fetchTree' that generalizes existing fetchers like
'fetchGit', 'fetchMercurial' and 'fetchTarball'. 'fetchTree' takes a
set of attributes, e.g.

  fetchTree {
    type = "git";
    url = "https://example.org/repo.git";
    ref = "some-branch";
    rev = "abcdef...";
  }

The existing fetchers are just wrappers around this. Note that the
input attributes to fetchTree are the same as flake input
specifications and flake lock file entries.

All fetchers share a common cache stored in
~/.cache/nix/fetcher-cache-v1.sqlite. This replaces the ad hoc caching
mechanisms in fetchGit and download.cc (e.g. ~/.cache/nix/{tarballs,git-revs*}).

This also adds support for Git worktrees (c169ea5904).
2020-04-07 09:03:14 +02:00

89 lines
3.1 KiB
C++

#include "primops.hh"
#include "eval-inline.hh"
#include "store-api.hh"
#include "fetchers.hh"
#include "url.hh"
#include <regex>
namespace nix {
static void prim_fetchMercurial(EvalState & state, const Pos & pos, Value * * args, Value & v)
{
std::string url;
std::optional<Hash> rev;
std::optional<std::string> ref;
std::string name = "source";
PathSet context;
state.forceValue(*args[0]);
if (args[0]->type == tAttrs) {
state.forceAttrs(*args[0], pos);
for (auto & attr : *args[0]->attrs) {
string n(attr.name);
if (n == "url")
url = state.coerceToString(*attr.pos, *attr.value, context, false, false);
else if (n == "rev") {
// Ugly: unlike fetchGit, here the "rev" attribute can
// be both a revision or a branch/tag name.
auto value = state.forceStringNoCtx(*attr.value, *attr.pos);
if (std::regex_match(value, revRegex))
rev = Hash(value, htSHA1);
else
ref = value;
}
else if (n == "name")
name = state.forceStringNoCtx(*attr.value, *attr.pos);
else
throw EvalError("unsupported argument '%s' to 'fetchMercurial', at %s", attr.name, *attr.pos);
}
if (url.empty())
throw EvalError(format("'url' argument required, at %1%") % pos);
} else
url = state.coerceToString(pos, *args[0], context, false, false);
// FIXME: git externals probably can be used to bypass the URI
// whitelist. Ah well.
state.checkURI(url);
if (evalSettings.pureEval && !rev)
throw Error("in pure evaluation mode, 'fetchMercurial' requires a Mercurial revision");
auto parsedUrl = parseURL(
url.find("://") != std::string::npos
? "hg+" + url
: "hg+file://" + url);
if (rev) parsedUrl.query.insert_or_assign("rev", rev->gitRev());
if (ref) parsedUrl.query.insert_or_assign("ref", *ref);
// FIXME: use name
auto input = fetchers::inputFromURL(parsedUrl);
auto [tree, input2] = input->fetchTree(state.store);
state.mkAttrs(v, 8);
auto storePath = state.store->printStorePath(tree.storePath);
mkString(*state.allocAttr(v, state.sOutPath), storePath, PathSet({storePath}));
if (input2->getRef())
mkString(*state.allocAttr(v, state.symbols.create("branch")), *input2->getRef());
// Backward compatibility: set 'rev' to
// 0000000000000000000000000000000000000000 for a dirty tree.
auto rev2 = input2->getRev().value_or(Hash(htSHA1));
mkString(*state.allocAttr(v, state.symbols.create("rev")), rev2.gitRev());
mkString(*state.allocAttr(v, state.symbols.create("shortRev")), std::string(rev2.gitRev(), 0, 12));
if (tree.info.revCount)
mkInt(*state.allocAttr(v, state.symbols.create("revCount")), *tree.info.revCount);
v.attrs->sort();
if (state.allowedPaths)
state.allowedPaths->insert(tree.actualPath);
}
static RegisterPrimOp r("fetchMercurial", 1, prim_fetchMercurial);
}