rocksdb/table/block_based/index_reader_common.cc

57 lines
2.1 KiB
C++

// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
//
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "table/block_based/index_reader_common.h"
namespace ROCKSDB_NAMESPACE {
Status BlockBasedTable::IndexReaderCommon::ReadIndexBlock(
const BlockBasedTable* table, FilePrefetchBuffer* prefetch_buffer,
const ReadOptions& read_options, bool use_cache, GetContext* get_context,
BlockCacheLookupContext* lookup_context,
CachableEntry<Block>* index_block) {
PERF_TIMER_GUARD(read_index_block_nanos);
assert(table != nullptr);
assert(index_block != nullptr);
assert(index_block->IsEmpty());
const Rep* const rep = table->get_rep();
assert(rep != nullptr);
const Status s = table->RetrieveBlock(
prefetch_buffer, read_options, rep->footer.index_handle(),
UncompressionDict::GetEmptyDict(), index_block, BlockType::kIndex,
get_context, lookup_context, /* for_compaction */ false, use_cache,
/* wait_for_cache */ true, /* async_read */ false);
return s;
}
Status BlockBasedTable::IndexReaderCommon::GetOrReadIndexBlock(
bool no_io, Env::IOPriority rate_limiter_priority, GetContext* get_context,
BlockCacheLookupContext* lookup_context,
CachableEntry<Block>* index_block) const {
assert(index_block != nullptr);
if (!index_block_.IsEmpty()) {
index_block->SetUnownedValue(index_block_.GetValue());
return Status::OK();
}
ReadOptions read_options;
read_options.rate_limiter_priority = rate_limiter_priority;
if (no_io) {
read_options.read_tier = kBlockCacheTier;
}
return ReadIndexBlock(table_, /*prefetch_buffer=*/nullptr, read_options,
cache_index_blocks(), get_context, lookup_context,
index_block);
}
} // namespace ROCKSDB_NAMESPACE