rocksdb/table/block_based/reader_common.h
Peter Dillinger 3cacd4b4ec Put Cache and CacheWrapper in new public header (#11192)
Summary:
The definition of the Cache class should not be needed by the vast majority of RocksDB users, so I think it is just distracting to include it in cache.h, which is primarily needed for configuring and creating caches. This change moves the class to a new header advanced_cache.h. It is just cut-and-paste except for modifying the class API comment.

In general, operations on shared_ptr<Cache> should continue to work when only a forward declaration of Cache is available, as long as all the Cache instances provided are already shared_ptr. See https://stackoverflow.com/a/17650101/454544

Also, the most common way to customize a Cache is by wrapping an existing implementation, so it makes sense to provide CacheWrapper in the public API. This was a cut-and-paste job except removing the implementation of Name() so that derived classes must provide it.

Intended follow-up: consolidate Release() into one function to reduce customization bugs / confusion

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11192

Test Plan: `make check`

Reviewed By: anand1976

Differential Revision: D43055487

Pulled By: pdillinger

fbshipit-source-id: 7b05492df35e0f30b581b4c24c579bc275b6d110
2023-02-09 12:12:02 -08:00

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// 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.
#pragma once
#include "rocksdb/advanced_cache.h"
#include "rocksdb/table.h"
namespace ROCKSDB_NAMESPACE {
// Release the cached entry and decrement its ref count.
extern void ForceReleaseCachedEntry(void* arg, void* h);
inline MemoryAllocator* GetMemoryAllocator(
const BlockBasedTableOptions& table_options) {
return table_options.block_cache.get()
? table_options.block_cache->memory_allocator()
: nullptr;
}
// Assumes block has a trailer as in format.h. file_name and offset provided
// for generating a diagnostic message in returned status.
extern Status VerifyBlockChecksum(ChecksumType type, const char* data,
size_t block_size,
const std::string& file_name,
uint64_t offset);
} // namespace ROCKSDB_NAMESPACE