diff options
Diffstat (limited to 'third_party/nix/src/libstore/remote-fs-accessor.cc')
-rw-r--r-- | third_party/nix/src/libstore/remote-fs-accessor.cc | 131 |
1 files changed, 131 insertions, 0 deletions
diff --git a/third_party/nix/src/libstore/remote-fs-accessor.cc b/third_party/nix/src/libstore/remote-fs-accessor.cc new file mode 100644 index 000000000000..ca478c213fde --- /dev/null +++ b/third_party/nix/src/libstore/remote-fs-accessor.cc @@ -0,0 +1,131 @@ +#include "remote-fs-accessor.hh" + +#include <fcntl.h> +#include <sys/stat.h> +#include <sys/types.h> + +#include "json.hh" +#include "nar-accessor.hh" + +namespace nix { + +RemoteFSAccessor::RemoteFSAccessor(const ref<Store>& store, + const Path& cacheDir) + : store(store), cacheDir(cacheDir) { + if (!cacheDir.empty()) { + createDirs(cacheDir); + } +} + +Path RemoteFSAccessor::makeCacheFile(const Path& storePath, + const std::string& ext) { + assert(!cacheDir.empty()); + return fmt("%s/%s.%s", cacheDir, storePathToHash(storePath), ext); +} + +void RemoteFSAccessor::addToCache(const Path& storePath, const std::string& nar, + const ref<FSAccessor>& narAccessor) { + nars.emplace(storePath, narAccessor); + + if (!cacheDir.empty()) { + try { + std::ostringstream str; + JSONPlaceholder jsonRoot(str); + listNar(jsonRoot, narAccessor, "", true); + writeFile(makeCacheFile(storePath, "ls"), str.str()); + + /* FIXME: do this asynchronously. */ + writeFile(makeCacheFile(storePath, "nar"), nar); + + } catch (...) { + ignoreException(); + } + } +} + +std::pair<ref<FSAccessor>, Path> RemoteFSAccessor::fetch(const Path& path_) { + auto path = canonPath(path_); + + auto storePath = store->toStorePath(path); + std::string restPath = std::string(path, storePath.size()); + + if (!store->isValidPath(storePath)) { + throw InvalidPath(format("path '%1%' is not a valid store path") % + storePath); + } + + auto i = nars.find(storePath); + if (i != nars.end()) { + return {i->second, restPath}; + } + + StringSink sink; + std::string listing; + Path cacheFile; + + if (!cacheDir.empty() && + pathExists(cacheFile = makeCacheFile(storePath, "nar"))) { + try { + listing = nix::readFile(makeCacheFile(storePath, "ls")); + + auto narAccessor = makeLazyNarAccessor( + listing, [cacheFile](uint64_t offset, uint64_t length) { + AutoCloseFD fd = open(cacheFile.c_str(), O_RDONLY | O_CLOEXEC); + if (!fd) { + throw SysError("opening NAR cache file '%s'", cacheFile); + } + + if (lseek(fd.get(), offset, SEEK_SET) != (off_t)offset) { + throw SysError("seeking in '%s'", cacheFile); + } + + std::string buf(length, 0); + readFull(fd.get(), (unsigned char*)buf.data(), length); + + return buf; + }); + + nars.emplace(storePath, narAccessor); + return {narAccessor, restPath}; + + } catch (SysError&) { + } + + try { + *sink.s = nix::readFile(cacheFile); + + auto narAccessor = makeNarAccessor(sink.s); + nars.emplace(storePath, narAccessor); + return {narAccessor, restPath}; + + } catch (SysError&) { + } + } + + store->narFromPath(storePath, sink); + auto narAccessor = makeNarAccessor(sink.s); + addToCache(storePath, *sink.s, narAccessor); + return {narAccessor, restPath}; +} + +FSAccessor::Stat RemoteFSAccessor::stat(const Path& path) { + auto res = fetch(path); + return res.first->stat(res.second); +} + +StringSet RemoteFSAccessor::readDirectory(const Path& path) { + auto res = fetch(path); + return res.first->readDirectory(res.second); +} + +std::string RemoteFSAccessor::readFile(const Path& path) { + auto res = fetch(path); + return res.first->readFile(res.second); +} + +std::string RemoteFSAccessor::readLink(const Path& path) { + auto res = fetch(path); + return res.first->readLink(res.second); +} + +} // namespace nix |