9eb3e1f77d
Summary: Use delete to disable automatic generated methods instead of private, and put the constructor together for more clear.This modification cause the unused field warning, so add unused attribute to disable this warning. Pull Request resolved: https://github.com/facebook/rocksdb/pull/5009 Differential Revision: D17288733 fbshipit-source-id: 8a767ce096f185f1db01bd28fc88fef1cdd921f3
83 lines
2.3 KiB
C++
83 lines
2.3 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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//
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#pragma once
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#ifndef ROCKSDB_LITE
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#include <memory>
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#include <string>
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#include "rocksdb/env.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 "util/file_reader_writer.h"
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#include "utilities/blob_db/blob_log_format.h"
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namespace rocksdb {
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class SequentialFileReader;
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class Logger;
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namespace blob_db {
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/**
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* Reader is a general purpose log stream reader implementation. The actual job
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* of reading from the device is implemented by the SequentialFile interface.
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*
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* Please see Writer for details on the file and record layout.
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*/
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class Reader {
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public:
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enum ReadLevel {
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kReadHeader,
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kReadHeaderKey,
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kReadHeaderKeyBlob,
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};
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// Create a reader that will return log records from "*file".
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// "*file" must remain live while this Reader is in use.
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Reader(std::unique_ptr<RandomAccessFileReader>&& file_reader, Env* env,
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Statistics* statistics);
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// No copying allowed
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Reader(const Reader&) = delete;
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Reader& operator=(const Reader&) = delete;
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~Reader() = default;
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Status ReadHeader(BlobLogHeader* header);
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// Read the next record into *record. Returns true if read
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// successfully, false if we hit end of the input. May use
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// "*scratch" as temporary storage. The contents filled in *record
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// will only be valid until the next mutating operation on this
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// reader or the next mutation to *scratch.
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// If blob_offset is non-null, return offset of the blob through it.
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Status ReadRecord(BlobLogRecord* record, ReadLevel level = kReadHeader,
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uint64_t* blob_offset = nullptr);
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void ResetNextByte() { next_byte_ = 0; }
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uint64_t GetNextByte() const { return next_byte_; }
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private:
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Status ReadSlice(uint64_t size, Slice* slice, char* buf);
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const std::unique_ptr<RandomAccessFileReader> file_;
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Env* env_;
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Statistics* statistics_;
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Slice buffer_;
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char header_buf_[BlobLogRecord::kHeaderSize];
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// which byte to read next. For asserting proper usage
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uint64_t next_byte_;
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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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