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#include "remote-fs-accessor.hh"
#include "nar-accessor.hh"
#include "json.hh"
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
namespace nix {
RemoteFSAccessor::RemoteFSAccessor(ref<Store> store, const Path & cacheDir)
: store(store)
, cacheDir(cacheDir)
{
if (cacheDir != "")
createDirs(cacheDir);
}
Path RemoteFSAccessor::makeCacheFile(std::string_view hashPart, const std::string & ext)
{
assert(cacheDir != "");
return fmt("%s/%s.%s", cacheDir, hashPart, ext);
}
void RemoteFSAccessor::addToCache(std::string_view hashPart, const std::string & nar,
ref<FSAccessor> narAccessor)
{
nars.emplace(hashPart, narAccessor);
if (cacheDir != "") {
try {
std::ostringstream str;
JSONPlaceholder jsonRoot(str);
listNar(jsonRoot, narAccessor, "", true);
writeFile(makeCacheFile(hashPart, "ls"), str.str());
/* FIXME: do this asynchronously. */
writeFile(makeCacheFile(hashPart, "nar"), nar);
} catch (...) {
ignoreException();
}
}
}
std::pair<ref<FSAccessor>, Path> RemoteFSAccessor::fetch(const Path & path_)
{
auto path = canonPath(path_);
auto [storePath, restPath] = store->toStorePath(path);
if (!store->isValidPath(storePath))
throw InvalidPath("path '%1%' is not a valid store path", store->printStorePath(storePath));
auto i = nars.find(std::string(storePath.hashPart()));
if (i != nars.end()) return {i->second, restPath};
StringSink sink;
std::string listing;
Path cacheFile;
if (cacheDir != "" && pathExists(cacheFile = makeCacheFile(storePath.hashPart(), "nar"))) {
try {
listing = nix::readFile(makeCacheFile(storePath.hashPart(), "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.hashPart(), narAccessor);
return {narAccessor, restPath};
} catch (SysError &) { }
try {
*sink.s = nix::readFile(cacheFile);
auto narAccessor = makeNarAccessor(sink.s);
nars.emplace(storePath.hashPart(), narAccessor);
return {narAccessor, restPath};
} catch (SysError &) { }
}
store->narFromPath(storePath, sink);
auto narAccessor = makeNarAccessor(sink.s);
addToCache(storePath.hashPart(), *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);
}
}
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