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rocksdb/db/blob/blob_contents.h

56 lines
1.7 KiB

// Copyright (c) Meta Platforms, Inc. and affiliates.
// 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 <memory>
#include "memory/memory_allocator.h"
#include "rocksdb/cache.h"
#include "rocksdb/rocksdb_namespace.h"
#include "rocksdb/slice.h"
#include "rocksdb/status.h"
namespace ROCKSDB_NAMESPACE {
// A class representing a single uncompressed value read from a blob file.
class BlobContents {
public:
static std::unique_ptr<BlobContents> Create(CacheAllocationPtr&& allocation,
size_t size);
BlobContents(const BlobContents&) = delete;
BlobContents& operator=(const BlobContents&) = delete;
BlobContents(BlobContents&&) = default;
BlobContents& operator=(BlobContents&&) = default;
~BlobContents() = default;
const Slice& data() const { return data_; }
size_t size() const { return data_.size(); }
size_t ApproximateMemoryUsage() const;
// Callbacks for secondary cache
static size_t SizeCallback(void* obj);
static Status SaveToCallback(void* from_obj, size_t from_offset,
size_t length, void* out);
static Cache::CacheItemHelper* GetCacheItemHelper();
static Status CreateCallback(const void* buf, size_t size, void** out_obj,
size_t* charge);
private:
BlobContents(CacheAllocationPtr&& allocation, size_t size)
: allocation_(std::move(allocation)), data_(allocation_.get(), size) {}
CacheAllocationPtr allocation_;
Slice data_;
};
} // namespace ROCKSDB_NAMESPACE