Summary: To prepare for adding checksum to footer and "context aware" checksums. This also brings closely related code much closer together. Recently added `BlockBasedTableBuilder::ComputeBlockTrailer` for testing is made obsolete in the refactoring, as testing the checksums can happen at a lower level of abstraction. Also now checking for unrecognized checksum type on reading footer, rather than later on use. Also removed an obsolete function delcaration. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9113 Test Plan: existing tests worked before refactoring to remove `ComputeBlockTrailer`. And then refactored+improved tests using it. Reviewed By: mrambacher Differential Revision: D32090149 Pulled By: pdillinger fbshipit-source-id: 2879da683c1498ea85a3b70dace9b6d9f6b47b6e
519 lines
19 KiB
C++
519 lines
19 KiB
C++
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
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// This source code is licensed under both the GPLv2 (found in the
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// COPYING file in the root directory) and Apache 2.0 License
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// (found in the LICENSE.Apache file in the root directory).
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//
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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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#include "table/format.h"
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#include <cinttypes>
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#include <string>
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#include "block_fetcher.h"
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#include "file/random_access_file_reader.h"
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#include "memory/memory_allocator.h"
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#include "monitoring/perf_context_imp.h"
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#include "monitoring/statistics.h"
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#include "options/options_helper.h"
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#include "rocksdb/env.h"
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#include "rocksdb/options.h"
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#include "table/block_based/block.h"
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#include "table/block_based/block_based_table_reader.h"
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#include "table/persistent_cache_helper.h"
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#include "util/coding.h"
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#include "util/compression.h"
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#include "util/crc32c.h"
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#include "util/hash.h"
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#include "util/stop_watch.h"
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#include "util/string_util.h"
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#include "util/xxhash.h"
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namespace ROCKSDB_NAMESPACE {
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extern const uint64_t kLegacyBlockBasedTableMagicNumber;
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extern const uint64_t kBlockBasedTableMagicNumber;
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#ifndef ROCKSDB_LITE
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extern const uint64_t kLegacyPlainTableMagicNumber;
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extern const uint64_t kPlainTableMagicNumber;
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#else
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// ROCKSDB_LITE doesn't have plain table
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const uint64_t kLegacyPlainTableMagicNumber = 0;
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const uint64_t kPlainTableMagicNumber = 0;
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#endif
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const char* kHostnameForDbHostId = "__hostname__";
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bool ShouldReportDetailedTime(Env* env, Statistics* stats) {
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return env != nullptr && stats != nullptr &&
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stats->get_stats_level() > kExceptDetailedTimers;
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}
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void BlockHandle::EncodeTo(std::string* dst) const {
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// Sanity check that all fields have been set
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assert(offset_ != ~uint64_t{0});
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assert(size_ != ~uint64_t{0});
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PutVarint64Varint64(dst, offset_, size_);
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}
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Status BlockHandle::DecodeFrom(Slice* input) {
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if (GetVarint64(input, &offset_) && GetVarint64(input, &size_)) {
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return Status::OK();
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} else {
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// reset in case failure after partially decoding
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offset_ = 0;
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size_ = 0;
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return Status::Corruption("bad block handle");
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}
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}
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Status BlockHandle::DecodeSizeFrom(uint64_t _offset, Slice* input) {
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if (GetVarint64(input, &size_)) {
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offset_ = _offset;
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return Status::OK();
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} else {
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// reset in case failure after partially decoding
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offset_ = 0;
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size_ = 0;
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return Status::Corruption("bad block handle");
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}
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}
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// Return a string that contains the copy of handle.
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std::string BlockHandle::ToString(bool hex) const {
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std::string handle_str;
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EncodeTo(&handle_str);
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if (hex) {
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return Slice(handle_str).ToString(true);
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} else {
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return handle_str;
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}
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}
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const BlockHandle BlockHandle::kNullBlockHandle(0, 0);
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void IndexValue::EncodeTo(std::string* dst, bool have_first_key,
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const BlockHandle* previous_handle) const {
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if (previous_handle) {
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assert(handle.offset() == previous_handle->offset() +
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previous_handle->size() + kBlockTrailerSize);
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PutVarsignedint64(dst, handle.size() - previous_handle->size());
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} else {
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handle.EncodeTo(dst);
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}
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assert(dst->size() != 0);
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if (have_first_key) {
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PutLengthPrefixedSlice(dst, first_internal_key);
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}
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}
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Status IndexValue::DecodeFrom(Slice* input, bool have_first_key,
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const BlockHandle* previous_handle) {
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if (previous_handle) {
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int64_t delta;
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if (!GetVarsignedint64(input, &delta)) {
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return Status::Corruption("bad delta-encoded index value");
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}
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handle = BlockHandle(
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previous_handle->offset() + previous_handle->size() + kBlockTrailerSize,
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previous_handle->size() + delta);
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} else {
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Status s = handle.DecodeFrom(input);
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if (!s.ok()) {
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return s;
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}
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}
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if (!have_first_key) {
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first_internal_key = Slice();
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} else if (!GetLengthPrefixedSlice(input, &first_internal_key)) {
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return Status::Corruption("bad first key in block info");
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}
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return Status::OK();
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}
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std::string IndexValue::ToString(bool hex, bool have_first_key) const {
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std::string s;
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EncodeTo(&s, have_first_key, nullptr);
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if (hex) {
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return Slice(s).ToString(true);
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} else {
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return s;
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}
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}
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namespace {
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inline bool IsLegacyFooterFormat(uint64_t magic_number) {
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return magic_number == kLegacyBlockBasedTableMagicNumber ||
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magic_number == kLegacyPlainTableMagicNumber;
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}
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inline uint64_t UpconvertLegacyFooterFormat(uint64_t magic_number) {
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if (magic_number == kLegacyBlockBasedTableMagicNumber) {
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return kBlockBasedTableMagicNumber;
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}
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if (magic_number == kLegacyPlainTableMagicNumber) {
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return kPlainTableMagicNumber;
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}
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assert(false);
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return 0;
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}
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} // namespace
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// legacy footer format:
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// metaindex handle (varint64 offset, varint64 size)
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// index handle (varint64 offset, varint64 size)
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// <padding> to make the total size 2 * BlockHandle::kMaxEncodedLength
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// table_magic_number (8 bytes)
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// new footer format:
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// checksum type (char, 1 byte)
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// metaindex handle (varint64 offset, varint64 size)
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// index handle (varint64 offset, varint64 size)
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// <padding> to make the total size 2 * BlockHandle::kMaxEncodedLength + 1
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// footer version (4 bytes)
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// table_magic_number (8 bytes)
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void Footer::EncodeTo(std::string* dst) const {
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assert(HasInitializedTableMagicNumber());
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if (IsLegacyFooterFormat(table_magic_number())) {
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// has to be default checksum with legacy footer
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assert(checksum_ == kCRC32c);
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const size_t original_size = dst->size();
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metaindex_handle_.EncodeTo(dst);
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index_handle_.EncodeTo(dst);
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dst->resize(original_size + 2 * BlockHandle::kMaxEncodedLength); // Padding
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PutFixed32(dst, static_cast<uint32_t>(table_magic_number() & 0xffffffffu));
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PutFixed32(dst, static_cast<uint32_t>(table_magic_number() >> 32));
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assert(dst->size() == original_size + kVersion0EncodedLength);
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} else {
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const size_t original_size = dst->size();
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dst->push_back(static_cast<char>(checksum_));
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metaindex_handle_.EncodeTo(dst);
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index_handle_.EncodeTo(dst);
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dst->resize(original_size + kNewVersionsEncodedLength - 12); // Padding
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PutFixed32(dst, version());
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PutFixed32(dst, static_cast<uint32_t>(table_magic_number() & 0xffffffffu));
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PutFixed32(dst, static_cast<uint32_t>(table_magic_number() >> 32));
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assert(dst->size() == original_size + kNewVersionsEncodedLength);
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}
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}
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Footer::Footer(uint64_t _table_magic_number, uint32_t _version)
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: version_(_version),
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checksum_(kCRC32c),
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table_magic_number_(_table_magic_number) {
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// This should be guaranteed by constructor callers
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assert(!IsLegacyFooterFormat(_table_magic_number) || version_ == 0);
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}
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Status Footer::DecodeFrom(Slice* input) {
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assert(!HasInitializedTableMagicNumber());
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assert(input != nullptr);
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assert(input->size() >= kMinEncodedLength);
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const char* magic_ptr =
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input->data() + input->size() - kMagicNumberLengthByte;
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const uint32_t magic_lo = DecodeFixed32(magic_ptr);
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const uint32_t magic_hi = DecodeFixed32(magic_ptr + 4);
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uint64_t magic = ((static_cast<uint64_t>(magic_hi) << 32) |
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(static_cast<uint64_t>(magic_lo)));
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// We check for legacy formats here and silently upconvert them
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bool legacy = IsLegacyFooterFormat(magic);
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if (legacy) {
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magic = UpconvertLegacyFooterFormat(magic);
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}
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set_table_magic_number(magic);
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if (legacy) {
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// The size is already asserted to be at least kMinEncodedLength
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// at the beginning of the function
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input->remove_prefix(input->size() - kVersion0EncodedLength);
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version_ = 0 /* legacy */;
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checksum_ = kCRC32c;
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} else {
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version_ = DecodeFixed32(magic_ptr - 4);
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// Footer version 1 and higher will always occupy exactly this many bytes.
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// It consists of the checksum type, two block handles, padding,
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// a version number, and a magic number
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if (input->size() < kNewVersionsEncodedLength) {
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return Status::Corruption("input is too short to be an sstable");
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} else {
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input->remove_prefix(input->size() - kNewVersionsEncodedLength);
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}
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uint32_t chksum;
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if (!GetVarint32(input, &chksum)) {
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return Status::Corruption("bad checksum type");
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}
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checksum_ = static_cast<ChecksumType>(chksum);
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if (chksum != static_cast<uint32_t>(checksum_) ||
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!IsSupportedChecksumType(checksum_)) {
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return Status::Corruption("unknown checksum type " +
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ROCKSDB_NAMESPACE::ToString(chksum));
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}
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}
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Status result = metaindex_handle_.DecodeFrom(input);
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if (result.ok()) {
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result = index_handle_.DecodeFrom(input);
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}
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if (result.ok()) {
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// We skip over any leftover data (just padding for now) in "input"
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const char* end = magic_ptr + kMagicNumberLengthByte;
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*input = Slice(end, input->data() + input->size() - end);
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}
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return result;
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}
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std::string Footer::ToString() const {
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std::string result;
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result.reserve(1024);
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bool legacy = IsLegacyFooterFormat(table_magic_number_);
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if (legacy) {
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result.append("metaindex handle: " + metaindex_handle_.ToString() + "\n ");
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result.append("index handle: " + index_handle_.ToString() + "\n ");
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result.append("table_magic_number: " +
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ROCKSDB_NAMESPACE::ToString(table_magic_number_) + "\n ");
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} else {
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result.append("checksum: " + ROCKSDB_NAMESPACE::ToString(checksum_) +
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"\n ");
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result.append("metaindex handle: " + metaindex_handle_.ToString() + "\n ");
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result.append("index handle: " + index_handle_.ToString() + "\n ");
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result.append("footer version: " + ROCKSDB_NAMESPACE::ToString(version_) +
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"\n ");
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result.append("table_magic_number: " +
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ROCKSDB_NAMESPACE::ToString(table_magic_number_) + "\n ");
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}
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return result;
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}
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Status ReadFooterFromFile(const IOOptions& opts, RandomAccessFileReader* file,
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FilePrefetchBuffer* prefetch_buffer,
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uint64_t file_size, Footer* footer,
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uint64_t enforce_table_magic_number) {
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if (file_size < Footer::kMinEncodedLength) {
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return Status::Corruption("file is too short (" + ToString(file_size) +
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" bytes) to be an "
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"sstable: " +
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file->file_name());
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}
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std::string footer_buf;
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AlignedBuf internal_buf;
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Slice footer_input;
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size_t read_offset =
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(file_size > Footer::kMaxEncodedLength)
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? static_cast<size_t>(file_size - Footer::kMaxEncodedLength)
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: 0;
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Status s;
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// TODO: Need to pass appropriate deadline to TryReadFromCache(). Right now,
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// there is no readahead for point lookups, so TryReadFromCache will fail if
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// the required data is not in the prefetch buffer. Once deadline is enabled
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// for iterator, TryReadFromCache might do a readahead. Revisit to see if we
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// need to pass a timeout at that point
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if (prefetch_buffer == nullptr ||
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!prefetch_buffer->TryReadFromCache(IOOptions(), read_offset,
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Footer::kMaxEncodedLength,
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&footer_input, nullptr)) {
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if (file->use_direct_io()) {
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s = file->Read(opts, read_offset, Footer::kMaxEncodedLength,
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&footer_input, nullptr, &internal_buf);
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} else {
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footer_buf.reserve(Footer::kMaxEncodedLength);
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s = file->Read(opts, read_offset, Footer::kMaxEncodedLength,
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&footer_input, &footer_buf[0], nullptr);
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}
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if (!s.ok()) return s;
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}
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// Check that we actually read the whole footer from the file. It may be
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// that size isn't correct.
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if (footer_input.size() < Footer::kMinEncodedLength) {
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return Status::Corruption("file is too short (" + ToString(file_size) +
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" bytes) to be an "
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"sstable" +
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file->file_name());
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}
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s = footer->DecodeFrom(&footer_input);
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if (!s.ok()) {
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return s;
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}
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if (enforce_table_magic_number != 0 &&
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enforce_table_magic_number != footer->table_magic_number()) {
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return Status::Corruption(
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"Bad table magic number: expected " +
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ToString(enforce_table_magic_number) + ", found " +
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ToString(footer->table_magic_number()) + " in " + file->file_name());
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}
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return Status::OK();
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}
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namespace {
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// Custom handling for the last byte of a block, to avoid invoking streaming
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// API to get an effective block checksum. This function is its own inverse
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// because it uses xor.
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inline uint32_t ModifyChecksumForLastByte(uint32_t checksum, char last_byte) {
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// This strategy bears some resemblance to extending a CRC checksum by one
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// more byte, except we don't need to re-mix the input checksum as long as
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// we do this step only once (per checksum).
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const uint32_t kRandomPrime = 0x6b9083d9;
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return checksum ^ static_cast<uint8_t>(last_byte) * kRandomPrime;
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}
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} // namespace
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uint32_t ComputeBuiltinChecksum(ChecksumType type, const char* data,
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size_t data_size) {
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switch (type) {
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case kCRC32c:
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return crc32c::Mask(crc32c::Value(data, data_size));
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case kxxHash:
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return XXH32(data, data_size, /*seed*/ 0);
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case kxxHash64:
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return Lower32of64(XXH64(data, data_size, /*seed*/ 0));
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case kXXH3: {
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if (data_size == 0) {
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// Special case because of special handling for last byte, not
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// present in this case. Can be any value different from other
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// small input size checksums.
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return 0;
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} else {
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// See corresponding code in ComputeBuiltinChecksumWithLastByte
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uint32_t v = Lower32of64(XXH3_64bits(data, data_size - 1));
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return ModifyChecksumForLastByte(v, data[data_size - 1]);
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}
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}
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default: // including kNoChecksum
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return 0;
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}
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}
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uint32_t ComputeBuiltinChecksumWithLastByte(ChecksumType type, const char* data,
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size_t data_size, char last_byte) {
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switch (type) {
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case kCRC32c: {
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uint32_t crc = crc32c::Value(data, data_size);
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// Extend to cover last byte (compression type)
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crc = crc32c::Extend(crc, &last_byte, 1);
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return crc32c::Mask(crc);
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}
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case kxxHash: {
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XXH32_state_t* const state = XXH32_createState();
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XXH32_reset(state, 0);
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XXH32_update(state, data, data_size);
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// Extend to cover last byte (compression type)
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XXH32_update(state, &last_byte, 1);
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uint32_t v = XXH32_digest(state);
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XXH32_freeState(state);
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return v;
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}
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case kxxHash64: {
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XXH64_state_t* const state = XXH64_createState();
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XXH64_reset(state, 0);
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XXH64_update(state, data, data_size);
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// Extend to cover last byte (compression type)
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XXH64_update(state, &last_byte, 1);
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uint32_t v = Lower32of64(XXH64_digest(state));
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XXH64_freeState(state);
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return v;
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}
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case kXXH3: {
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// XXH3 is a complicated hash function that is extremely fast on
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// contiguous input, but that makes its streaming support rather
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// complex. It is worth custom handling of the last byte (`type`)
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// in order to avoid allocating a large state object and bringing
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// that code complexity into CPU working set.
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uint32_t v = Lower32of64(XXH3_64bits(data, data_size));
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return ModifyChecksumForLastByte(v, last_byte);
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}
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default: // including kNoChecksum
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return 0;
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}
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}
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Status UncompressBlockContentsForCompressionType(
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const UncompressionInfo& uncompression_info, const char* data, size_t n,
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BlockContents* contents, uint32_t format_version,
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const ImmutableOptions& ioptions, MemoryAllocator* allocator) {
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Status ret = Status::OK();
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assert(uncompression_info.type() != kNoCompression &&
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"Invalid compression type");
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StopWatchNano timer(ioptions.clock,
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ShouldReportDetailedTime(ioptions.env, ioptions.stats));
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size_t uncompressed_size = 0;
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CacheAllocationPtr ubuf =
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UncompressData(uncompression_info, data, n, &uncompressed_size,
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GetCompressFormatForVersion(format_version), allocator);
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if (!ubuf) {
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if (!CompressionTypeSupported(uncompression_info.type())) {
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return Status::NotSupported(
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"Unsupported compression method for this build",
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CompressionTypeToString(uncompression_info.type()));
|
|
} else {
|
|
return Status::Corruption(
|
|
"Corrupted compressed block contents",
|
|
CompressionTypeToString(uncompression_info.type()));
|
|
}
|
|
}
|
|
|
|
*contents = BlockContents(std::move(ubuf), uncompressed_size);
|
|
|
|
if (ShouldReportDetailedTime(ioptions.env, ioptions.stats)) {
|
|
RecordTimeToHistogram(ioptions.stats, DECOMPRESSION_TIMES_NANOS,
|
|
timer.ElapsedNanos());
|
|
}
|
|
RecordTimeToHistogram(ioptions.stats, BYTES_DECOMPRESSED,
|
|
contents->data.size());
|
|
RecordTick(ioptions.stats, NUMBER_BLOCK_DECOMPRESSED);
|
|
|
|
TEST_SYNC_POINT_CALLBACK(
|
|
"UncompressBlockContentsForCompressionType:TamperWithReturnValue",
|
|
static_cast<void*>(&ret));
|
|
TEST_SYNC_POINT_CALLBACK(
|
|
"UncompressBlockContentsForCompressionType:"
|
|
"TamperWithDecompressionOutput",
|
|
static_cast<void*>(contents));
|
|
|
|
return ret;
|
|
}
|
|
|
|
//
|
|
// The 'data' points to the raw block contents that was read in from file.
|
|
// This method allocates a new heap buffer and the raw block
|
|
// contents are uncompresed into this buffer. This
|
|
// buffer is returned via 'result' and it is upto the caller to
|
|
// free this buffer.
|
|
// format_version is the block format as defined in include/rocksdb/table.h
|
|
Status UncompressBlockContents(const UncompressionInfo& uncompression_info,
|
|
const char* data, size_t n,
|
|
BlockContents* contents, uint32_t format_version,
|
|
const ImmutableOptions& ioptions,
|
|
MemoryAllocator* allocator) {
|
|
assert(data[n] != kNoCompression);
|
|
assert(data[n] == static_cast<char>(uncompression_info.type()));
|
|
return UncompressBlockContentsForCompressionType(uncompression_info, data, n,
|
|
contents, format_version,
|
|
ioptions, allocator);
|
|
}
|
|
|
|
// Replace the contents of db_host_id with the actual hostname, if db_host_id
|
|
// matches the keyword kHostnameForDbHostId
|
|
Status ReifyDbHostIdProperty(Env* env, std::string* db_host_id) {
|
|
assert(db_host_id);
|
|
if (*db_host_id == kHostnameForDbHostId) {
|
|
Status s = env->GetHostNameString(db_host_id);
|
|
if (!s.ok()) {
|
|
db_host_id->clear();
|
|
}
|
|
return s;
|
|
}
|
|
|
|
return Status::OK();
|
|
}
|
|
} // namespace ROCKSDB_NAMESPACE
|