guix/src/libstore/misc.cc

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#include "build.hh"
Derivation derivationFromPath(const Path & drvPath)
{
assertStorePath(drvPath);
ensurePath(drvPath);
ATerm t = ATreadFromNamedFile(drvPath.c_str());
if (!t) throw Error(format("cannot read aterm from `%1%'") % drvPath);
return parseDerivation(t);
}
void computeFSClosure(const Path & storePath,
PathSet & paths, bool flipDirection)
{
if (paths.find(storePath) != paths.end()) return;
paths.insert(storePath);
PathSet references;
if (flipDirection)
queryReferers(noTxn, storePath, references);
else
queryReferences(noTxn, storePath, references);
for (PathSet::iterator i = references.begin();
i != references.end(); ++i)
computeFSClosure(*i, paths, flipDirection);
}
Path findOutput(const Derivation & drv, string id)
{
for (DerivationOutputs::const_iterator i = drv.outputs.begin();
i != drv.outputs.end(); ++i)
if (i->first == id) return i->second.path;
throw Error(format("derivation has no output `%1%'") % id);
}