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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).
//
#pragma once
#include <cassert>
#include "table/block_based/cachable_entry.h"
#include "table/format.h"
namespace ROCKSDB_NAMESPACE {
class BlockBasedTable;
struct BlockCacheLookupContext;
class FilePrefetchBuffer;
class GetContext;
struct ReadOptions;
struct UncompressionDict;
// Provides access to the uncompression dictionary regardless of whether
// it is owned by the reader or stored in the cache, or whether it is pinned
// in the cache or not.
class UncompressionDictReader {
public:
static Status Create(
const BlockBasedTable* table, FilePrefetchBuffer* prefetch_buffer,
bool use_cache, bool prefetch, bool pin,
BlockCacheLookupContext* lookup_context,
std::unique_ptr<UncompressionDictReader>* uncompression_dict_reader);
Status GetOrReadUncompressionDictionary(
FilePrefetchBuffer* prefetch_buffer, bool no_io, GetContext* get_context,
BlockCacheLookupContext* lookup_context,
CachableEntry<UncompressionDict>* uncompression_dict) const;
size_t ApproximateMemoryUsage() const;
private:
UncompressionDictReader(const BlockBasedTable* t,
CachableEntry<UncompressionDict>&& uncompression_dict)
: table_(t), uncompression_dict_(std::move(uncompression_dict)) {
assert(table_);
}
bool cache_dictionary_blocks() const;
static Status ReadUncompressionDictionary(
const BlockBasedTable* table, FilePrefetchBuffer* prefetch_buffer,
const ReadOptions& read_options, bool use_cache, GetContext* get_context,
BlockCacheLookupContext* lookup_context,
CachableEntry<UncompressionDict>* uncompression_dict);
const BlockBasedTable* table_;
CachableEntry<UncompressionDict> uncompression_dict_;
};
} // namespace ROCKSDB_NAMESPACE
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