mirror of https://github.com/facebook/rocksdb.git
121 lines
3.9 KiB
C++
121 lines
3.9 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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// 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 <atomic>
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#include <sstream>
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#include <string>
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#include "port/port.h"
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#include "rocksdb/env.h"
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#include "rocksdb/listener.h"
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#include "rocksdb/rate_limiter.h"
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#include "util/aligned_buffer.h"
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namespace rocksdb {
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class Statistics;
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class HistogramImpl;
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// RandomAccessFileReader is a wrapper on top of Env::RnadomAccessFile. It is
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// responsible for:
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// - Handling Buffered and Direct reads appropriately.
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// - Rate limiting compaction reads.
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// - Notifying any interested listeners on the completion of a read.
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// - Updating IO stats.
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class RandomAccessFileReader {
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private:
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#ifndef ROCKSDB_LITE
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void NotifyOnFileReadFinish(uint64_t offset, size_t length,
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const FileOperationInfo::TimePoint& start_ts,
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const FileOperationInfo::TimePoint& finish_ts,
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const Status& status) const {
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FileOperationInfo info(file_name_, start_ts, finish_ts);
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info.offset = offset;
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info.length = length;
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info.status = status;
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for (auto& listener : listeners_) {
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listener->OnFileReadFinish(info);
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}
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}
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#endif // ROCKSDB_LITE
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bool ShouldNotifyListeners() const { return !listeners_.empty(); }
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std::unique_ptr<RandomAccessFile> file_;
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std::string file_name_;
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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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RateLimiter* rate_limiter_;
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std::vector<std::shared_ptr<EventListener>> listeners_;
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public:
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explicit RandomAccessFileReader(
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std::unique_ptr<RandomAccessFile>&& raf, std::string _file_name,
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Env* env = nullptr, Statistics* stats = nullptr, uint32_t hist_type = 0,
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HistogramImpl* file_read_hist = nullptr,
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RateLimiter* rate_limiter = nullptr,
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const std::vector<std::shared_ptr<EventListener>>& listeners = {})
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: file_(std::move(raf)),
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file_name_(std::move(_file_name)),
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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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rate_limiter_(rate_limiter),
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listeners_() {
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#ifndef ROCKSDB_LITE
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std::for_each(listeners.begin(), listeners.end(),
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[this](const std::shared_ptr<EventListener>& e) {
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if (e->ShouldBeNotifiedOnFileIO()) {
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listeners_.emplace_back(e);
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}
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});
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#else // !ROCKSDB_LITE
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(void)listeners;
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#endif
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}
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RandomAccessFileReader(RandomAccessFileReader&& o) ROCKSDB_NOEXCEPT {
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*this = std::move(o);
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}
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RandomAccessFileReader& operator=(RandomAccessFileReader&& o)
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ROCKSDB_NOEXCEPT {
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file_ = std::move(o.file_);
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env_ = std::move(o.env_);
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stats_ = std::move(o.stats_);
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hist_type_ = std::move(o.hist_type_);
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file_read_hist_ = std::move(o.file_read_hist_);
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rate_limiter_ = std::move(o.rate_limiter_);
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return *this;
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}
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RandomAccessFileReader(const RandomAccessFileReader&) = delete;
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RandomAccessFileReader& operator=(const RandomAccessFileReader&) = delete;
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Status Read(uint64_t offset, size_t n, Slice* result, char* scratch,
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bool for_compaction = false) const;
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Status MultiRead(ReadRequest* reqs, size_t num_reqs) const;
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Status Prefetch(uint64_t offset, size_t n) const {
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return file_->Prefetch(offset, n);
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}
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RandomAccessFile* file() { return file_.get(); }
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std::string file_name() const { return file_name_; }
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bool use_direct_io() const { return file_->use_direct_io(); }
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};
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} // namespace rocksdb
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