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https://github.com/facebook/sapling.git
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49385c8a07
Summary: C++17 Reviewed By: fanzeyi Differential Revision: D28966939 fbshipit-source-id: c8c9d49bc02557263a6acf9357c90b50e04fbdb9
97 lines
3.0 KiB
C++
97 lines
3.0 KiB
C++
/*
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* Copyright (c) Facebook, Inc. and its affiliates.
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*
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* This software may be used and distributed according to the terms of the
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* GNU General Public License version 2.
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*/
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#include "eden/fs/store/TreeMetadata.h"
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#include <folly/Conv.h>
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#include <folly/io/Cursor.h>
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#include <folly/lang/Bits.h>
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#include <folly/logging/xlog.h>
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#include "eden/fs/store/BlobMetadata.h"
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#include "eden/fs/store/StoreResult.h"
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namespace facebook::eden {
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using folly::ByteRange;
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using folly::IOBuf;
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using folly::StringPiece;
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using folly::io::Appender;
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TreeMetadata::TreeMetadata(EntryMetadata entryMetadata)
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: entryMetadata_(std::move(entryMetadata)) {}
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size_t TreeMetadata::getNumberOfEntries() const {
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return std::visit(
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[](auto&& entryMetadata) { return entryMetadata.size(); },
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entryMetadata_);
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}
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size_t TreeMetadata::getSerializedSize() const {
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return sizeof(uint32_t) + ENTRY_SIZE * getNumberOfEntries();
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}
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IOBuf TreeMetadata::serialize() const {
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// serialize tree metadata as: <number of entries><hash for first
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// entry><serialized metadata for first entry> ... <hash for last
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// entry><serialized metadata for last entry>
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IOBuf buf(IOBuf::CREATE, getSerializedSize());
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Appender appender(&buf, 0);
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auto numberOfEntries = getNumberOfEntries();
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XCHECK_LE(numberOfEntries, std::numeric_limits<uint32_t>::max());
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appender.write<uint32_t>(folly::to_narrow(numberOfEntries));
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auto hashIndexedEntries =
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std::get_if<HashIndexedEntryMetadata>(&entryMetadata_);
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if (!hashIndexedEntries) {
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throw std::domain_error(
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"Identifiers for entries are not hashes, can not serialize.");
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}
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for (auto& [hash, metadata] : *hashIndexedEntries) {
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appender.push(hash.getBytes());
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SerializedBlobMetadata serializedMetadata(metadata);
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appender.push(serializedMetadata.slice());
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}
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return buf;
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}
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TreeMetadata TreeMetadata::deserialize(const StoreResult& result) {
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auto data = result.piece();
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if (data.size() < sizeof(uint32_t)) {
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throw std::invalid_argument(
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"buffer too small -- serialized tree contains unknown number of entries");
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}
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uint32_t numberOfEntries;
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memcpy(&numberOfEntries, data.data(), sizeof(uint32_t));
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data.advance(sizeof(uint32_t));
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if (data.size() < numberOfEntries * ENTRY_SIZE) {
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throw std::invalid_argument(
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"buffer too small -- serialized tree does not contain metadata for all "
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" entries");
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}
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HashIndexedEntryMetadata entryMetadata;
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entryMetadata.reserve(numberOfEntries);
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for (uint32_t i = 0; i < numberOfEntries; ++i) {
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auto temp = ByteRange{StringPiece{data, 0, Hash::RAW_SIZE}};
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auto hash = Hash{temp};
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data.advance(Hash::RAW_SIZE);
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auto serializedMetadata =
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ByteRange{StringPiece{data, 0, SerializedBlobMetadata::SIZE}};
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BlobMetadata metadata = SerializedBlobMetadata::unslice(serializedMetadata);
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data.advance(SerializedBlobMetadata::SIZE);
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entryMetadata.push_back(std::make_pair(hash, metadata));
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}
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return TreeMetadata(entryMetadata);
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}
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} // namespace facebook::eden
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