mirror of https://github.com/facebook/rocksdb.git
61 lines
1.8 KiB
C++
61 lines
1.8 KiB
C++
// Copyright (c) Meta Platforms, Inc. and affiliates.
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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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#pragma once
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#include <memory>
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#include "memory/memory_allocator_impl.h"
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#include "rocksdb/advanced_cache.h"
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#include "rocksdb/rocksdb_namespace.h"
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#include "rocksdb/slice.h"
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#include "rocksdb/status.h"
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namespace ROCKSDB_NAMESPACE {
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// A class representing a single uncompressed value read from a blob file.
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class BlobContents {
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public:
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BlobContents(CacheAllocationPtr&& allocation, size_t size)
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: allocation_(std::move(allocation)), data_(allocation_.get(), size) {}
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BlobContents(const BlobContents&) = delete;
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BlobContents& operator=(const BlobContents&) = delete;
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BlobContents(BlobContents&&) = default;
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BlobContents& operator=(BlobContents&&) = default;
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~BlobContents() = default;
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const Slice& data() const { return data_; }
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size_t size() const { return data_.size(); }
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size_t ApproximateMemoryUsage() const;
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// For TypedCacheInterface
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const Slice& ContentSlice() const { return data_; }
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static constexpr CacheEntryRole kCacheEntryRole = CacheEntryRole::kBlobValue;
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private:
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CacheAllocationPtr allocation_;
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Slice data_;
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};
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class BlobContentsCreator : public Cache::CreateContext {
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public:
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static void Create(std::unique_ptr<BlobContents>* out, size_t* out_charge,
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const Slice& contents, CompressionType /*type*/,
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MemoryAllocator* alloc) {
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auto raw = new BlobContents(AllocateAndCopyBlock(contents, alloc),
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contents.size());
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out->reset(raw);
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if (out_charge) {
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*out_charge = raw->ApproximateMemoryUsage();
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}
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}
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};
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} // namespace ROCKSDB_NAMESPACE
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