mirror of https://github.com/facebook/rocksdb.git
117 lines
3.6 KiB
C++
117 lines
3.6 KiB
C++
// Copyright (c) 2013, 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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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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#pragma once
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#include "rocksdb/env.h"
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namespace rocksdb {
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class Statistics;
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class HistogramImpl;
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std::unique_ptr<RandomAccessFile> NewReadaheadRandomAccessFile(
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std::unique_ptr<RandomAccessFile> file, size_t readahead_size);
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class SequentialFileReader {
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private:
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std::unique_ptr<SequentialFile> file_;
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public:
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explicit SequentialFileReader(std::unique_ptr<SequentialFile>&& _file)
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: file_(std::move(_file)) {}
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Status Read(size_t n, Slice* result, char* scratch);
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Status Skip(uint64_t n);
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SequentialFile* file() { return file_.get(); }
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};
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class RandomAccessFileReader : public RandomAccessFile {
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private:
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std::unique_ptr<RandomAccessFile> file_;
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Env* env_;
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Statistics* stats_;
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uint32_t hist_type_;
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HistogramImpl* file_read_hist_;
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public:
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explicit RandomAccessFileReader(std::unique_ptr<RandomAccessFile>&& raf,
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Env* env = nullptr,
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Statistics* stats = nullptr,
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uint32_t hist_type = 0,
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HistogramImpl* file_read_hist = nullptr)
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: file_(std::move(raf)),
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env_(env),
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stats_(stats),
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hist_type_(hist_type),
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file_read_hist_(file_read_hist) {}
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Status Read(uint64_t offset, size_t n, Slice* result, char* scratch) const;
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RandomAccessFile* file() { return file_.get(); }
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};
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// Use posix write to write data to a file.
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class WritableFileWriter {
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private:
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std::unique_ptr<WritableFile> writable_file_;
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size_t cursize_; // current size of cached data in buf_
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size_t capacity_; // max size of buf_
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unique_ptr<char[]> buf_; // a buffer to cache writes
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uint64_t filesize_;
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bool pending_sync_;
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bool pending_fsync_;
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bool direct_io_;
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uint64_t last_sync_size_;
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uint64_t bytes_per_sync_;
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RateLimiter* rate_limiter_;
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public:
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explicit WritableFileWriter(std::unique_ptr<WritableFile>&& file,
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const EnvOptions& options)
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: writable_file_(std::move(file)),
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cursize_(0),
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capacity_(65536),
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buf_(new char[capacity_]),
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filesize_(0),
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pending_sync_(false),
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pending_fsync_(false),
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direct_io_(writable_file_->UseDirectIO()),
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last_sync_size_(0),
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bytes_per_sync_(options.bytes_per_sync),
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rate_limiter_(options.rate_limiter) {}
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~WritableFileWriter() { Flush(); }
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Status Append(const Slice& data);
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Status Flush();
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Status Close();
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Status Sync(bool use_fsync);
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// Sync only the data that was already Flush()ed. Safe to call concurrently
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// with Append() and Flush(). If !writable_file_->IsSyncThreadSafe(),
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// returns NotSupported status.
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Status SyncWithoutFlush(bool use_fsync);
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uint64_t GetFileSize() { return filesize_; }
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Status InvalidateCache(size_t offset, size_t length) {
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return writable_file_->InvalidateCache(offset, length);
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}
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WritableFile* writable_file() const { return writable_file_.get(); }
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private:
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Status RangeSync(off_t offset, off_t nbytes);
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size_t RequestToken(size_t bytes);
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Status SyncInternal(bool use_fsync);
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};
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} // namespace rocksdb
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