lix/src/libstore/misc.cc
2012-11-26 18:25:12 +01:00

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#include "misc.hh"
#include "store-api.hh"
#include "local-store.hh"
#include "globals.hh"
namespace nix {
Derivation derivationFromPath(StoreAPI & store, const Path & drvPath)
{
assertStorePath(drvPath);
store.ensurePath(drvPath);
return parseDerivation(readFile(drvPath));
}
void computeFSClosure(StoreAPI & store, const Path & storePath,
PathSet & paths, bool flipDirection, bool includeOutputs)
{
if (paths.find(storePath) != paths.end()) return;
paths.insert(storePath);
PathSet references;
if (flipDirection)
store.queryReferrers(storePath, references);
else
store.queryReferences(storePath, references);
if (includeOutputs && isDerivation(storePath)) {
PathSet outputs = store.queryDerivationOutputs(storePath);
foreach (PathSet::iterator, i, outputs)
if (store.isValidPath(*i))
computeFSClosure(store, *i, paths, flipDirection, true);
}
foreach (PathSet::iterator, i, references)
computeFSClosure(store, *i, paths, flipDirection, includeOutputs);
}
Path findOutput(const Derivation & drv, string id)
{
foreach (DerivationOutputs::const_iterator, i, drv.outputs)
if (i->first == id) return i->second.path;
throw Error(format("derivation has no output `%1%'") % id);
}
void queryMissing(StoreAPI & store, const PathSet & targets,
PathSet & willBuild, PathSet & willSubstitute, PathSet & unknown,
unsigned long long & downloadSize, unsigned long long & narSize)
{
downloadSize = narSize = 0;
PathSet todo(targets.begin(), targets.end()), done;
/* Getting substitute info has high latency when using the binary
cache substituter. Thus it's essential to do substitute
queries in parallel as much as possible. To accomplish this
we do the following:
- For all paths still to be processed (todo), we add all
paths for which we need info to the set query. For an
unbuilt derivation this is the output paths; otherwise, it's
the path itself.
- We get info about all paths in query in parallel.
- We process the results and add new items to todo if
necessary. E.g. if a path is substitutable, then we need to
get info on its references.
- Repeat until todo is empty.
*/
while (!todo.empty()) {
PathSet query, todoDrv, todoNonDrv;
foreach (PathSet::iterator, i, todo) {
if (done.find(*i) != done.end()) continue;
done.insert(*i);
DrvPathWithOutputs i2 = parseDrvPathWithOutputs(*i);
if (isDerivation(i2.first)) {
if (!store.isValidPath(i2.first)) {
// FIXME: we could try to substitute p.
unknown.insert(*i);
continue;
}
Derivation drv = derivationFromPath(store, i2.first);
PathSet invalid;
foreach (DerivationOutputs::iterator, j, drv.outputs)
if (wantOutput(j->first, i2.second)
&& !store.isValidPath(j->second.path))
invalid.insert(j->second.path);
if (invalid.empty()) continue;
todoDrv.insert(*i);
if (settings.useSubstitutes) query.insert(invalid.begin(), invalid.end());
}
else {
if (store.isValidPath(*i)) continue;
query.insert(*i);
todoNonDrv.insert(*i);
}
}
todo.clear();
SubstitutablePathInfos infos;
store.querySubstitutablePathInfos(query, infos);
foreach (PathSet::iterator, i, todoDrv) {
DrvPathWithOutputs i2 = parseDrvPathWithOutputs(*i);
// FIXME: cache this
Derivation drv = derivationFromPath(store, i2.first);
PathSet outputs;
bool mustBuild = false;
if (settings.useSubstitutes) {
foreach (DerivationOutputs::iterator, j, drv.outputs) {
if (!wantOutput(j->first, i2.second)) continue;
if (!store.isValidPath(j->second.path)) {
if (infos.find(j->second.path) == infos.end())
mustBuild = true;
else
outputs.insert(j->second.path);
}
}
} else
mustBuild = true;
if (mustBuild) {
willBuild.insert(i2.first);
todo.insert(drv.inputSrcs.begin(), drv.inputSrcs.end());
foreach (DerivationInputs::iterator, j, drv.inputDrvs)
todo.insert(makeDrvPathWithOutputs(j->first, j->second));
} else
todoNonDrv.insert(outputs.begin(), outputs.end());
}
foreach (PathSet::iterator, i, todoNonDrv) {
done.insert(*i);
SubstitutablePathInfos::iterator info = infos.find(*i);
if (info != infos.end()) {
willSubstitute.insert(*i);
downloadSize += info->second.downloadSize;
narSize += info->second.narSize;
todo.insert(info->second.references.begin(), info->second.references.end());
} else
unknown.insert(*i);
}
}
}
static void dfsVisit(StoreAPI & store, const PathSet & paths,
const Path & path, PathSet & visited, Paths & sorted,
PathSet & parents)
{
if (parents.find(path) != parents.end())
throw BuildError(format("cycle detected in the references of `%1%'") % path);
if (visited.find(path) != visited.end()) return;
visited.insert(path);
parents.insert(path);
PathSet references;
if (store.isValidPath(path))
store.queryReferences(path, references);
foreach (PathSet::iterator, i, references)
/* Don't traverse into paths that don't exist. That can
happen due to substitutes for non-existent paths. */
if (*i != path && paths.find(*i) != paths.end())
dfsVisit(store, paths, *i, visited, sorted, parents);
sorted.push_front(path);
parents.erase(path);
}
Paths topoSortPaths(StoreAPI & store, const PathSet & paths)
{
Paths sorted;
PathSet visited, parents;
foreach (PathSet::const_iterator, i, paths)
dfsVisit(store, paths, *i, visited, sorted, parents);
return sorted;
}
}