From 22d6e31fc6a9de2ee424984e629ccd2e394ba512 Mon Sep 17 00:00:00 2001 From: Eelco Dolstra Date: Wed, 17 Aug 2016 15:12:54 +0200 Subject: [PATCH] Add a mechanism for derivation attributes to reference the derivation's outputs MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit For example, you can now say: configureFlags = "--prefix=${placeholder "out"} --includedir=${placeholder "dev"}"; The strings returned by the ‘placeholder’ builtin are replaced at build time by the actual store paths corresponding to the specified outputs. Previously, you had to work around the inability to self-reference by doing stuff like: preConfigure = '' configureFlags+=" --prefix $out --includedir=$dev" ''; or rely on ad-hoc variable interpolation semantics in Autoconf or Make (e.g. --prefix=\$(out)), which doesn't always work. --- src/libexpr/primops.cc | 14 ++++++++++++++ src/libstore/build.cc | 29 +++++++++++++++-------------- src/libstore/derivations.cc | 7 +++++++ src/libstore/derivations.hh | 2 ++ tests/config.nix | 2 +- tests/local.mk | 3 ++- tests/placeholders.sh | 22 ++++++++++++++++++++++ 7 files changed, 63 insertions(+), 16 deletions(-) create mode 100644 tests/placeholders.sh diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc index 6a4a7a035..51ee16353 100644 --- a/src/libexpr/primops.cc +++ b/src/libexpr/primops.cc @@ -673,6 +673,19 @@ static void prim_derivationStrict(EvalState & state, const Pos & pos, Value * * } +/* 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 occurence 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 Pos & pos, Value * * args, Value & v) +{ + mkString(v, hashPlaceholder(state.forceStringNoCtx(*args[0], pos))); +} + + /************************************************************* * Paths *************************************************************/ @@ -1893,6 +1906,7 @@ void EvalState::createBaseEnv() // Derivations addPrimOp("derivationStrict", 1, prim_derivationStrict); + addPrimOp("placeholder", 1, prim_placeholder); // Networking addPrimOp("__fetchurl", 1, prim_fetchurl); diff --git a/src/libstore/build.cc b/src/libstore/build.cc index cfab0b0dc..0c687dfc1 100644 --- a/src/libstore/build.cc +++ b/src/libstore/build.cc @@ -652,18 +652,15 @@ HookInstance::~HookInstance() ////////////////////////////////////////////////////////////////////// -typedef map HashRewrites; +typedef map StringRewrites; -string rewriteHashes(string s, const HashRewrites & rewrites) +std::string rewriteStrings(std::string s, const StringRewrites & rewrites) { for (auto & i : rewrites) { - assert(i.first.size() == i.second.size()); size_t j = 0; - while ((j = s.find(i.first, j)) != string::npos) { - debug(format("rewriting @ %1%") % j); - s.replace(j, i.second.size(), i.second); - } + while ((j = s.find(i.first, j)) != string::npos) + s.replace(j, i.first.size(), i.second); } return s; } @@ -782,7 +779,7 @@ private: #endif /* Hash rewriting. */ - HashRewrites rewritesToTmp, rewritesFromTmp; + StringRewrites inputRewrites, outputRewrites; typedef map RedirectedOutputs; RedirectedOutputs redirectedOutputs; @@ -1774,6 +1771,10 @@ void DerivationGoal::startBuilder() for (auto & i : varNames) env[i] = getEnv(i); } + /* Substitute output placeholders with the actual output paths. */ + for (auto & output : drv->outputs) + inputRewrites[hashPlaceholder(output.first)] = output.second.path; + /* The `exportReferencesGraph' feature allows the references graph to be passed to a builder. This attribute should be a list of pairs [name1 path1 name2 path2 ...]. The references graph of @@ -2418,7 +2419,7 @@ void DerivationGoal::runChild() /* Fill in the environment. */ Strings envStrs; for (auto & i : env) - envStrs.push_back(rewriteHashes(i.first + "=" + i.second, rewritesToTmp)); + envStrs.push_back(rewriteStrings(i.first + "=" + i.second, inputRewrites)); /* If we are running in `build-users' mode, then switch to the user we allocated above. Make sure that we drop all root @@ -2560,7 +2561,7 @@ void DerivationGoal::runChild() } for (auto & i : drv->args) - args.push_back(rewriteHashes(i, rewritesToTmp)); + args.push_back(rewriteStrings(i, inputRewrites)); restoreSIGPIPE(); @@ -2682,7 +2683,7 @@ void DerivationGoal::registerOutputs() /* Apply hash rewriting if necessary. */ bool rewritten = false; - if (!rewritesFromTmp.empty()) { + if (!outputRewrites.empty()) { printMsg(lvlError, format("warning: rewriting hashes in ‘%1%’; cross fingers") % path); /* Canonicalise first. This ensures that the path we're @@ -2694,7 +2695,7 @@ void DerivationGoal::registerOutputs() StringSink sink; dumpPath(actualPath, sink); deletePath(actualPath); - sink.s = make_ref(rewriteHashes(*sink.s, rewritesFromTmp)); + sink.s = make_ref(rewriteStrings(*sink.s, outputRewrites)); StringSource source(*sink.s); restorePath(actualPath, source); @@ -3033,8 +3034,8 @@ Path DerivationGoal::addHashRewrite(const Path & path) Path p = worker.store.storeDir + "/" + h2 + string(path, worker.store.storeDir.size() + 33); deletePath(p); assert(path.size() == p.size()); - rewritesToTmp[h1] = h2; - rewritesFromTmp[h2] = h1; + inputRewrites[h1] = h2; + outputRewrites[h2] = h1; redirectedOutputs[path] = p; return p; } diff --git a/src/libstore/derivations.cc b/src/libstore/derivations.cc index 7dcf71d46..f051f10bd 100644 --- a/src/libstore/derivations.cc +++ b/src/libstore/derivations.cc @@ -390,4 +390,11 @@ Sink & operator << (Sink & out, const BasicDerivation & drv) } +std::string hashPlaceholder(const std::string & outputName) +{ + // FIXME: memoize? + return "/" + printHash32(hashString(htSHA256, "nix-output:" + outputName)); +} + + } diff --git a/src/libstore/derivations.hh b/src/libstore/derivations.hh index 974de78c5..9717a81e4 100644 --- a/src/libstore/derivations.hh +++ b/src/libstore/derivations.hh @@ -117,4 +117,6 @@ struct Sink; Source & readDerivation(Source & in, Store & store, BasicDerivation & drv); Sink & operator << (Sink & out, const BasicDerivation & drv); +std::string hashPlaceholder(const std::string & outputName); + } diff --git a/tests/config.nix b/tests/config.nix index 6244a15fa..76388fdd5 100644 --- a/tests/config.nix +++ b/tests/config.nix @@ -13,7 +13,7 @@ rec { derivation ({ inherit system; builder = shell; - args = ["-e" args.builder]; + args = ["-e" args.builder or (builtins.toFile "builder.sh" "eval \"$buildCommand\"")]; PATH = path; } // removeAttrs args ["builder" "meta"]) // { meta = args.meta or {}; }; diff --git a/tests/local.mk b/tests/local.mk index 1e5439f06..2ca52144b 100644 --- a/tests/local.mk +++ b/tests/local.mk @@ -10,7 +10,8 @@ nix_tests = \ timeout.sh secure-drv-outputs.sh nix-channel.sh \ multiple-outputs.sh import-derivation.sh fetchurl.sh optimise-store.sh \ binary-cache.sh nix-profile.sh repair.sh dump-db.sh case-hack.sh \ - check-reqs.sh pass-as-file.sh tarball.sh restricted.sh + check-reqs.sh pass-as-file.sh tarball.sh restricted.sh \ + placeholders.sh # parallel.sh install-tests += $(foreach x, $(nix_tests), tests/$(x)) diff --git a/tests/placeholders.sh b/tests/placeholders.sh new file mode 100644 index 000000000..071cfe2dc --- /dev/null +++ b/tests/placeholders.sh @@ -0,0 +1,22 @@ +source common.sh + +clearStore + +nix-build --no-out-link -E ' + with import ./config.nix; + + mkDerivation { + name = "placeholders"; + outputs = [ "out" "bin" "dev" ]; + buildCommand = " + echo foo1 > $out + echo foo2 > $bin + echo foo3 > $dev + [[ $(cat ${placeholder "out"}) = foo1 ]] + [[ $(cat ${placeholder "bin"}) = foo2 ]] + [[ $(cat ${placeholder "dev"}) = foo3 ]] + "; + } +' + +echo XYZZY