0b2dffefea
Use ``` git show --color-moved --patience --color-moved-ws=ignore-all-space ``` to review and see that this is mostly code motion. Co-Authored-By: John Ericson <John.Ericson@Obsidian.Systems>
85 lines
2.2 KiB
C++
85 lines
2.2 KiB
C++
#include "nix/util/nar-cache.hh"
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#include "nix/util/file-system.hh"
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#include <nlohmann/json.hpp>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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namespace nix {
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NarCache::NarCache(std::optional<std::filesystem::path> cacheDir_)
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: cacheDir(std::move(cacheDir_))
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{
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if (cacheDir)
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createDirs(*cacheDir);
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}
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ref<SourceAccessor> NarCache::getOrInsert(const Hash & narHash, std::function<void(Sink &)> populate)
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{
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// Check in-memory cache first
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if (auto * accessor = get(nars, narHash))
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return *accessor;
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auto cacheAccessor = [&](ref<SourceAccessor> accessor) {
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nars.emplace(narHash, accessor);
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return accessor;
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};
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auto getNar = [&]() {
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StringSink sink;
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populate(sink);
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return std::move(sink.s);
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};
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if (cacheDir) {
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auto makeCacheFile = [&](const std::string & ext) {
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auto res = *cacheDir / narHash.to_string(HashFormat::Nix32, false);
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res += ".";
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res += ext;
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return res;
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};
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auto cacheFile = makeCacheFile("nar");
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auto listingFile = makeCacheFile("ls");
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if (nix::pathExists(cacheFile)) {
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try {
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return cacheAccessor(makeLazyNarAccessor(
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nlohmann::json::parse(nix::readFile(listingFile)).template get<NarListing>(),
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seekableGetNarBytes(cacheFile)));
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} catch (SystemError &) {
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}
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try {
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return cacheAccessor(makeNarAccessor(nix::readFile(cacheFile)));
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} catch (SystemError &) {
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}
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}
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auto nar = getNar();
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try {
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/* FIXME: do this asynchronously. */
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writeFile(cacheFile, nar);
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} catch (...) {
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ignoreExceptionExceptInterrupt();
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}
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auto narAccessor = makeNarAccessor(std::move(nar));
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try {
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nlohmann::json j = narAccessor->getListing();
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writeFile(listingFile, j.dump());
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} catch (...) {
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ignoreExceptionExceptInterrupt();
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}
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return cacheAccessor(narAccessor);
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}
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return cacheAccessor(makeNarAccessor(getNar()));
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}
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} // namespace nix
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