lix/src/nix/copy.cc
2016-04-22 18:19:48 +02:00

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#include "command.hh"
#include "progress-bar.hh"
#include "shared.hh"
#include "store-api.hh"
#include "sync.hh"
#include "thread-pool.hh"
#include <atomic>
using namespace nix;
struct CmdCopy : StorePathsCommand
{
std::string srcUri, dstUri;
CmdCopy()
{
mkFlag(0, "from", "store-uri", "URI of the source Nix store", &srcUri);
mkFlag(0, "to", "store-uri", "URI of the destination Nix store", &dstUri);
}
std::string name() override
{
return "copy";
}
std::string description() override
{
return "copy paths between Nix stores";
}
Examples examples() override
{
return {
Example{
"To copy Firefox to the local store to a binary cache in file:///tmp/cache:",
"nix copy --to file:///tmp/cache -r $(type -p firefox)"
},
};
}
void run(ref<Store> store, Paths storePaths) override
{
if (srcUri.empty() && dstUri.empty())
throw UsageError("you must pass --from and/or --to");
ref<Store> srcStore = srcUri.empty() ? store : openStoreAt(srcUri);
ref<Store> dstStore = dstUri.empty() ? store : openStoreAt(dstUri);
ProgressBar progressBar;
std::atomic<size_t> done{0};
std::atomic<size_t> total{storePaths.size()};
auto showProgress = [&]() {
return (format("[%d/%d copied]") % done % total).str();
};
progressBar.updateStatus(showProgress());
struct Graph
{
std::set<Path> left;
std::map<Path, std::set<Path>> refs, rrefs;
};
Sync<Graph> graph_;
{
auto graph(graph_.lock());
graph->left = PathSet(storePaths.begin(), storePaths.end());
}
ThreadPool pool;
std::function<void(const Path &)> doPath;
doPath = [&](const Path & storePath) {
checkInterrupt();
if (!dstStore->isValidPath(storePath)) {
auto activity(progressBar.startActivity(format("copying %s...") % storePath));
StringSink sink;
srcStore->exportPaths({storePath}, false, sink);
StringSource source(*sink.s);
dstStore->importPaths(false, source, 0);
done++;
} else
total--;
progressBar.updateStatus(showProgress());
/* Enqueue all paths that were waiting for this one. */
{
auto graph(graph_.lock());
graph->left.erase(storePath);
for (auto & rref : graph->rrefs[storePath]) {
auto & refs(graph->refs[rref]);
auto i = refs.find(storePath);
assert(i != refs.end());
refs.erase(i);
if (refs.empty())
pool.enqueue(std::bind(doPath, rref));
}
}
};
/* Build the dependency graph; enqueue all paths with no
dependencies. */
for (auto & storePath : storePaths) {
auto info = srcStore->queryPathInfo(storePath);
{
auto graph(graph_.lock());
for (auto & ref : info->references)
if (ref != storePath && graph->left.count(ref)) {
graph->refs[storePath].insert(ref);
graph->rrefs[ref].insert(storePath);
}
if (graph->refs[storePath].empty())
pool.enqueue(std::bind(doPath, storePath));
}
}
pool.process();
progressBar.done();
}
};
static RegisterCommand r1(make_ref<CmdCopy>());