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// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
//
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#pragma once
#include <atomic>
#include <string>
#include "db/version_edit.h"
#include "port/port.h"
#include "rocksdb/env.h"
#include "rocksdb/file_checksum.h"
#include "rocksdb/file_system.h"
#include "rocksdb/listener.h"
#include "rocksdb/rate_limiter.h"
#include "test_util/sync_point.h"
#include "util/aligned_buffer.h"
namespace ROCKSDB_NAMESPACE {
class Statistics;
// WritableFileWriter is a wrapper on top of Env::WritableFile. It provides
// facilities to:
// - Handle Buffered and Direct writes.
// - Rate limit writes.
// - Flush and Sync the data to the underlying filesystem.
// - Notify any interested listeners on the completion of a write.
// - Update IO stats.
class WritableFileWriter {
private:
#ifndef ROCKSDB_LITE
void NotifyOnFileWriteFinish(uint64_t offset, size_t length,
const FileOperationInfo::TimePoint& start_ts,
const FileOperationInfo::TimePoint& finish_ts,
const Status& status) {
FileOperationInfo info(file_name_, start_ts, finish_ts);
info.offset = offset;
info.length = length;
info.status = status;
for (auto& listener : listeners_) {
listener->OnFileWriteFinish(info);
}
}
#endif // ROCKSDB_LITE
bool ShouldNotifyListeners() const { return !listeners_.empty(); }
void CalculateFileChecksum(const Slice& data);
std::unique_ptr<FSWritableFile> writable_file_;
std::string file_name_;
Env* env_;
AlignedBuffer buf_;
size_t max_buffer_size_;
// Actually written data size can be used for truncate
// not counting padding data
uint64_t filesize_;
#ifndef ROCKSDB_LITE
// This is necessary when we use unbuffered access
// and writes must happen on aligned offsets
// so we need to go back and write that page again
uint64_t next_write_offset_;
#endif // ROCKSDB_LITE
bool pending_sync_;
uint64_t last_sync_size_;
uint64_t bytes_per_sync_;
RateLimiter* rate_limiter_;
Statistics* stats_;
std::vector<std::shared_ptr<EventListener>> listeners_;
FileChecksumFunc* checksum_func_;
std::string file_checksum_ = kUnknownFileChecksum;
bool is_first_checksum_ = true;
public:
WritableFileWriter(
std::unique_ptr<FSWritableFile>&& file, const std::string& _file_name,
const FileOptions& options, Env* env = nullptr,
Statistics* stats = nullptr,
const std::vector<std::shared_ptr<EventListener>>& listeners = {},
FileChecksumFunc* checksum_func = nullptr)
: writable_file_(std::move(file)),
file_name_(_file_name),
env_(env),
buf_(),
max_buffer_size_(options.writable_file_max_buffer_size),
filesize_(0),
#ifndef ROCKSDB_LITE
next_write_offset_(0),
#endif // ROCKSDB_LITE
pending_sync_(false),
last_sync_size_(0),
bytes_per_sync_(options.bytes_per_sync),
rate_limiter_(options.rate_limiter),
stats_(stats),
listeners_(),
checksum_func_(checksum_func) {
TEST_SYNC_POINT_CALLBACK("WritableFileWriter::WritableFileWriter:0",
reinterpret_cast<void*>(max_buffer_size_));
buf_.Alignment(writable_file_->GetRequiredBufferAlignment());
buf_.AllocateNewBuffer(std::min((size_t)65536, max_buffer_size_));
#ifndef ROCKSDB_LITE
std::for_each(listeners.begin(), listeners.end(),
[this](const std::shared_ptr<EventListener>& e) {
if (e->ShouldBeNotifiedOnFileIO()) {
listeners_.emplace_back(e);
}
});
#else // !ROCKSDB_LITE
(void)listeners;
#endif
}
WritableFileWriter(const WritableFileWriter&) = delete;
WritableFileWriter& operator=(const WritableFileWriter&) = delete;
~WritableFileWriter() { Close(); }
std::string file_name() const { return file_name_; }
Status Append(const Slice& data);
Status Pad(const size_t pad_bytes);
Status Flush();
Status Close();
Status Sync(bool use_fsync);
// Sync only the data that was already Flush()ed. Safe to call concurrently
// with Append() and Flush(). If !writable_file_->IsSyncThreadSafe(),
// returns NotSupported status.
Status SyncWithoutFlush(bool use_fsync);
uint64_t GetFileSize() const { return filesize_; }
Status InvalidateCache(size_t offset, size_t length) {
return writable_file_->InvalidateCache(offset, length);
}
FSWritableFile* writable_file() const { return writable_file_.get(); }
bool use_direct_io() { return writable_file_->use_direct_io(); }
bool TEST_BufferIsEmpty() { return buf_.CurrentSize() == 0; }
void TEST_SetFileChecksumFunc(FileChecksumFunc* checksum_func) {
checksum_func_ = checksum_func;
}
const std::string& GetFileChecksum() const { return file_checksum_; }
const char* GetFileChecksumFuncName() const;
private:
// Used when os buffering is OFF and we are writing
// DMA such as in Direct I/O mode
#ifndef ROCKSDB_LITE
Status WriteDirect();
#endif // !ROCKSDB_LITE
// Normal write
Status WriteBuffered(const char* data, size_t size);
Status RangeSync(uint64_t offset, uint64_t nbytes);
Status SyncInternal(bool use_fsync);
};
} // namespace ROCKSDB_NAMESPACE
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