99 lines
2.9 KiB
C
99 lines
2.9 KiB
C
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// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
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// This source code is licensed under the BSD-style license found in the
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// LICENSE file in the root directory of this source tree. An additional grant
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// of patent rights can be found in the PATENTS file in the same directory.
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//
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#pragma once
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#ifndef ROCKSDB_LITE
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#include <cstdint>
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#include <memory>
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#include <string>
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#include "rocksdb/slice.h"
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#include "rocksdb/status.h"
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#include "rocksdb/types.h"
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#include "utilities/blob_db/blob_log_format.h"
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namespace rocksdb {
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class WritableFileWriter;
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namespace blob_db {
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/**
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* Writer 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 Writer {
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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 Writer is in use.
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explicit Writer(std::unique_ptr<WritableFileWriter>&& dest,
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uint64_t log_number, uint64_t bpsync, bool use_fsync,
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uint64_t boffset = 0);
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~Writer();
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static void ConstructBlobHeader(std::string* headerbuf, const Slice& key,
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const Slice& val, int32_t ttl, int64_t ts);
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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* key_offset,
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uint64_t* blob_offset, uint32_t ttl);
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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 AddRecordFooter(const SequenceNumber& sn);
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Status AppendFooter(const BlobLogFooter& footer);
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Status WriteHeader(const 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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bool ShouldSync() const { return block_offset_ > next_sync_offset_; }
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void Sync();
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void ResetSyncPointer() { next_sync_offset_ += bytes_per_sync_; }
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private:
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std::unique_ptr<WritableFileWriter> dest_;
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uint64_t log_number_;
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uint64_t block_offset_; // Current offset in block
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uint64_t bytes_per_sync_;
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uint64_t next_sync_offset_;
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bool use_fsync_;
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// crc32c values for all supported record types. These are
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// pre-computed to reduce the overhead of computing the crc of the
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// record type stored in the header.
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uint32_t type_crc_[kMaxRecordType + 1];
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// No copying allowed
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Writer(const Writer&) = delete;
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Writer& operator=(const Writer&) = delete;
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public:
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enum ElemType { kEtNone, kEtFileHdr, kEtRecord, kEtFooter, kEtFileFooter };
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ElemType last_elem_type_;
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};
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} // namespace blob_db
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} // namespace rocksdb
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#endif // ROCKSDB_LITE
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