mirror of https://github.com/facebook/rocksdb.git
84 lines
2.6 KiB
C++
84 lines
2.6 KiB
C++
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
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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 <cstdint>
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#include <memory>
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#include <string>
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#include "db/blob/blob_log_format.h"
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#include "rocksdb/slice.h"
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#include "rocksdb/statistics.h"
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#include "rocksdb/status.h"
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#include "rocksdb/types.h"
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namespace ROCKSDB_NAMESPACE {
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class WritableFileWriter;
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class SystemClock;
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/**
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* BlobLogWriter is the blob log stream writer. It provides an append-only
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* abstraction for writing blob data.
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*
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*
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* Look at blob_db_format.h to see the details of the record formats.
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*/
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class BlobLogWriter {
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public:
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// Create a writer that will append data to "*dest".
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// "*dest" must be initially empty.
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// "*dest" must remain live while this BlobLogWriter is in use.
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BlobLogWriter(std::unique_ptr<WritableFileWriter>&& dest, SystemClock* clock,
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Statistics* statistics, uint64_t log_number, bool use_fsync,
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bool do_flush, uint64_t boffset = 0);
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// No copying allowed
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BlobLogWriter(const BlobLogWriter&) = delete;
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BlobLogWriter& operator=(const BlobLogWriter&) = delete;
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~BlobLogWriter();
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static void ConstructBlobHeader(std::string* buf, const Slice& key,
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const Slice& val, uint64_t expiration);
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Status AddRecord(const Slice& key, const Slice& val, uint64_t* key_offset,
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uint64_t* blob_offset);
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Status AddRecord(const Slice& key, const Slice& val, uint64_t expiration,
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uint64_t* key_offset, uint64_t* blob_offset);
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Status EmitPhysicalRecord(const std::string& headerbuf, const Slice& key,
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const Slice& val, uint64_t* key_offset,
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uint64_t* blob_offset);
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Status AppendFooter(BlobLogFooter& footer, std::string* checksum_method,
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std::string* checksum_value);
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Status WriteHeader(BlobLogHeader& header);
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WritableFileWriter* file() { return dest_.get(); }
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const WritableFileWriter* file() const { return dest_.get(); }
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uint64_t get_log_number() const { return log_number_; }
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Status Sync();
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private:
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std::unique_ptr<WritableFileWriter> dest_;
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SystemClock* clock_;
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Statistics* statistics_;
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uint64_t log_number_;
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uint64_t block_offset_; // Current offset in block
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bool use_fsync_;
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bool do_flush_;
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public:
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enum ElemType { kEtNone, kEtFileHdr, kEtRecord, kEtFileFooter };
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ElemType last_elem_type_;
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};
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} // namespace ROCKSDB_NAMESPACE
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