lix/src/libstore/misc.cc
John Ericson 242f9bf3dc std::visit by reference
I had started the trend of doing `std::visit` by value (because a type
error once mislead me into thinking that was the only form that
existed). While the optomizer in principle should be able to deal with
extra coppying or extra indirection once the lambdas inlined, sticking
with by reference is the conventional default. I hope this might even
improve performance.
2021-09-30 21:35:09 +00:00

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#include "derivations.hh"
#include "parsed-derivations.hh"
#include "globals.hh"
#include "local-store.hh"
#include "store-api.hh"
#include "thread-pool.hh"
#include "topo-sort.hh"
#include "callback.hh"
#include "closure.hh"
namespace nix {
void Store::computeFSClosure(const StorePathSet & startPaths,
StorePathSet & paths_, bool flipDirection, bool includeOutputs, bool includeDerivers)
{
std::function<std::set<StorePath>(const StorePath & path, std::future<ref<const ValidPathInfo>> &)> queryDeps;
if (flipDirection)
queryDeps = [&](const StorePath& path,
std::future<ref<const ValidPathInfo>> & fut) {
StorePathSet res;
StorePathSet referrers;
queryReferrers(path, referrers);
for (auto& ref : referrers)
if (ref != path)
res.insert(ref);
if (includeOutputs)
for (auto& i : queryValidDerivers(path))
res.insert(i);
if (includeDerivers && path.isDerivation())
for (auto& [_, maybeOutPath] : queryPartialDerivationOutputMap(path))
if (maybeOutPath && isValidPath(*maybeOutPath))
res.insert(*maybeOutPath);
return res;
};
else
queryDeps = [&](const StorePath& path,
std::future<ref<const ValidPathInfo>> & fut) {
StorePathSet res;
auto info = fut.get();
for (auto& ref : info->references)
if (ref != path)
res.insert(ref);
if (includeOutputs && path.isDerivation())
for (auto& [_, maybeOutPath] : queryPartialDerivationOutputMap(path))
if (maybeOutPath && isValidPath(*maybeOutPath))
res.insert(*maybeOutPath);
if (includeDerivers && info->deriver && isValidPath(*info->deriver))
res.insert(*info->deriver);
return res;
};
computeClosure<StorePath>(
startPaths, paths_,
[&](const StorePath& path,
std::function<void(std::promise<std::set<StorePath>>&)>
processEdges) {
std::promise<std::set<StorePath>> promise;
std::function<void(std::future<ref<const ValidPathInfo>>)>
getDependencies =
[&](std::future<ref<const ValidPathInfo>> fut) {
try {
promise.set_value(queryDeps(path, fut));
} catch (...) {
promise.set_exception(std::current_exception());
}
};
queryPathInfo(path, getDependencies);
processEdges(promise);
});
}
void Store::computeFSClosure(const StorePath & startPath,
StorePathSet & paths_, bool flipDirection, bool includeOutputs, bool includeDerivers)
{
StorePathSet paths;
paths.insert(startPath);
computeFSClosure(paths, paths_, flipDirection, includeOutputs, includeDerivers);
}
std::optional<ContentAddress> getDerivationCA(const BasicDerivation & drv)
{
auto out = drv.outputs.find("out");
if (out != drv.outputs.end()) {
if (auto v = std::get_if<DerivationOutputCAFixed>(&out->second.output))
return v->hash;
}
return std::nullopt;
}
void Store::queryMissing(const std::vector<DerivedPath> & targets,
StorePathSet & willBuild_, StorePathSet & willSubstitute_, StorePathSet & unknown_,
uint64_t & downloadSize_, uint64_t & narSize_)
{
Activity act(*logger, lvlDebug, actUnknown, "querying info about missing paths");
downloadSize_ = narSize_ = 0;
ThreadPool pool;
struct State
{
std::unordered_set<std::string> done;
StorePathSet & unknown, & willSubstitute, & willBuild;
uint64_t & downloadSize;
uint64_t & narSize;
};
struct DrvState
{
size_t left;
bool done = false;
StorePathSet outPaths;
DrvState(size_t left) : left(left) { }
};
Sync<State> state_(State{{}, unknown_, willSubstitute_, willBuild_, downloadSize_, narSize_});
std::function<void(DerivedPath)> doPath;
auto mustBuildDrv = [&](const StorePath & drvPath, const Derivation & drv) {
{
auto state(state_.lock());
state->willBuild.insert(drvPath);
}
for (auto & i : drv.inputDrvs)
pool.enqueue(std::bind(doPath, DerivedPath::Built { i.first, i.second }));
};
auto checkOutput = [&](
const StorePath & drvPath, ref<Derivation> drv, const StorePath & outPath, ref<Sync<DrvState>> drvState_)
{
if (drvState_->lock()->done) return;
SubstitutablePathInfos infos;
querySubstitutablePathInfos({{outPath, getDerivationCA(*drv)}}, infos);
if (infos.empty()) {
drvState_->lock()->done = true;
mustBuildDrv(drvPath, *drv);
} else {
{
auto drvState(drvState_->lock());
if (drvState->done) return;
assert(drvState->left);
drvState->left--;
drvState->outPaths.insert(outPath);
if (!drvState->left) {
for (auto & path : drvState->outPaths)
pool.enqueue(std::bind(doPath, DerivedPath::Opaque { path } ));
}
}
}
};
doPath = [&](const DerivedPath & req) {
{
auto state(state_.lock());
if (!state->done.insert(req.to_string(*this)).second) return;
}
std::visit(overloaded {
[&](const DerivedPath::Built & bfd) {
if (!isValidPath(bfd.drvPath)) {
// FIXME: we could try to substitute the derivation.
auto state(state_.lock());
state->unknown.insert(bfd.drvPath);
return;
}
StorePathSet invalid;
/* true for regular derivations, and CA derivations for which we
have a trust mapping for all wanted outputs. */
auto knownOutputPaths = true;
for (auto & [outputName, pathOpt] : queryPartialDerivationOutputMap(bfd.drvPath)) {
if (!pathOpt) {
knownOutputPaths = false;
break;
}
if (wantOutput(outputName, bfd.outputs) && !isValidPath(*pathOpt))
invalid.insert(*pathOpt);
}
if (knownOutputPaths && invalid.empty()) return;
auto drv = make_ref<Derivation>(derivationFromPath(bfd.drvPath));
ParsedDerivation parsedDrv(StorePath(bfd.drvPath), *drv);
if (knownOutputPaths && settings.useSubstitutes && parsedDrv.substitutesAllowed()) {
auto drvState = make_ref<Sync<DrvState>>(DrvState(invalid.size()));
for (auto & output : invalid)
pool.enqueue(std::bind(checkOutput, bfd.drvPath, drv, output, drvState));
} else
mustBuildDrv(bfd.drvPath, *drv);
},
[&](const DerivedPath::Opaque & bo) {
if (isValidPath(bo.path)) return;
SubstitutablePathInfos infos;
querySubstitutablePathInfos({{bo.path, std::nullopt}}, infos);
if (infos.empty()) {
auto state(state_.lock());
state->unknown.insert(bo.path);
return;
}
auto info = infos.find(bo.path);
assert(info != infos.end());
{
auto state(state_.lock());
state->willSubstitute.insert(bo.path);
state->downloadSize += info->second.downloadSize;
state->narSize += info->second.narSize;
}
for (auto & ref : info->second.references)
pool.enqueue(std::bind(doPath, DerivedPath::Opaque { ref }));
},
}, req.raw());
};
for (auto & path : targets)
pool.enqueue(std::bind(doPath, path));
pool.process();
}
StorePaths Store::topoSortPaths(const StorePathSet & paths)
{
return topoSort(paths,
{[&](const StorePath & path) {
StorePathSet references;
try {
references = queryPathInfo(path)->references;
} catch (InvalidPath &) {
}
return references;
}},
{[&](const StorePath & path, const StorePath & parent) {
return BuildError(
"cycle detected in the references of '%s' from '%s'",
printStorePath(path),
printStorePath(parent));
}});
}
std::map<DrvOutput, StorePath> drvOutputReferences(
const std::set<Realisation> & inputRealisations,
const StorePathSet & pathReferences)
{
std::map<DrvOutput, StorePath> res;
for (const auto & input : inputRealisations) {
if (pathReferences.count(input.outPath)) {
res.insert({input.id, input.outPath});
}
}
return res;
}
std::map<DrvOutput, StorePath> drvOutputReferences(
Store & store,
const Derivation & drv,
const StorePath & outputPath)
{
std::set<Realisation> inputRealisations;
for (const auto& [inputDrv, outputNames] : drv.inputDrvs) {
auto outputHashes =
staticOutputHashes(store, store.readDerivation(inputDrv));
for (const auto& outputName : outputNames) {
auto thisRealisation = store.queryRealisation(
DrvOutput{outputHashes.at(outputName), outputName});
if (!thisRealisation)
throw Error(
"output '%s' of derivation '%s' isnt built", outputName,
store.printStorePath(inputDrv));
inputRealisations.insert(*thisRealisation);
}
}
auto info = store.queryPathInfo(outputPath);
return drvOutputReferences(Realisation::closure(store, inputRealisations), info->references);
}
}