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#include "libstore/remote-fs-accessor.hh"
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include "libstore/nar-accessor.hh"
#include "libutil/json.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
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