hashed-mirrors: Use parsed derivation output rather than reconstructing it

Now the derivation outputs are parsed up front, we can avoid a reparse
by doing it. Also, this just feels a bit better as the `output*` env
vars are more of a `libnixexpr` interface than `libnixstore` interface:
ultimately, it's the derivation outputs that decide whether the
derivation is fixed-output.

Yes, hashed mirrors might go away with #3689, but this bit of code would
be moved rather than deleted, so it's worth doing a cleanup anyways I
think.
This commit is contained in:
John Ericson 2020-06-22 15:17:20 +00:00
parent 965b80347e
commit f4a5913125

View file

@ -58,13 +58,16 @@ void builtinFetchurl(const BasicDerivation & drv, const std::string & netrcData)
}
};
/* We always have one output, and if it's a fixed-output derivation (as
checked below) it must be the only output */
auto & output = drv.outputs.begin()->second;
/* Try the hashed mirrors first. */
if (getAttr("outputHashMode") == "flat")
if (output.hash && output.hash->method == FileIngestionMethod::Flat)
for (auto hashedMirror : settings.hashedMirrors.get())
try {
if (!hasSuffix(hashedMirror, "/")) hashedMirror += '/';
auto ht = parseHashTypeOpt(getAttr("outputHashAlgo"));
auto h = Hash(getAttr("outputHash"), ht);
auto & h = output.hash->hash;
fetch(hashedMirror + printHashType(*h.type) + "/" + h.to_string(Base16, false));
return;
} catch (Error & e) {