rocksdb/util/io_posix.h

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// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree. An additional grant
// of patent rights can be found in the PATENTS file in the same 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 <errno.h>
#include <unistd.h>
#include <atomic>
#include <string>
#include "rocksdb/env.h"
// For non linux platform, the following macros are used only as place
// holder.
#if !(defined OS_LINUX) && !(defined CYGWIN)
#define POSIX_FADV_NORMAL 0 /* [MC1] no further special treatment */
#define POSIX_FADV_RANDOM 1 /* [MC1] expect random page refs */
#define POSIX_FADV_SEQUENTIAL 2 /* [MC1] expect sequential page refs */
#define POSIX_FADV_WILLNEED 3 /* [MC1] will need these pages */
#define POSIX_FADV_DONTNEED 4 /* [MC1] dont need these pages */
#endif
namespace rocksdb {
static Status IOError(const std::string& context, int err_number) {
return (err_number == ENOSPC) ?
Status::NoSpace(context, strerror(err_number)) :
Status::IOError(context, strerror(err_number));
}
class PosixHelper {
public:
static size_t GetUniqueIdFromFile(int fd, char* id, size_t max_size);
};
class PosixSequentialFile : public SequentialFile {
private:
std::string filename_;
FILE* file_;
int fd_;
bool use_direct_io_;
public:
PosixSequentialFile(const std::string& fname, FILE* file, int fd,
const EnvOptions& options);
virtual ~PosixSequentialFile();
virtual Status Read(size_t n, Slice* result, char* scratch) override;
virtual Status PositionedRead(uint64_t offset, size_t n, Slice* result,
char* scratch) override;
virtual Status Skip(uint64_t n) override;
virtual Status InvalidateCache(size_t offset, size_t length) override;
virtual bool use_direct_io() const override { return use_direct_io_; }
};
class PosixRandomAccessFile : public RandomAccessFile {
protected:
std::string filename_;
int fd_;
bool use_direct_io_;
public:
PosixRandomAccessFile(const std::string& fname, int fd,
const EnvOptions& options);
virtual ~PosixRandomAccessFile();
virtual Status Read(uint64_t offset, size_t n, Slice* result,
char* scratch) const override;
#if defined(OS_LINUX) || defined(OS_MACOSX)
virtual size_t GetUniqueId(char* id, size_t max_size) const override;
#endif
virtual void Hint(AccessPattern pattern) override;
virtual Status InvalidateCache(size_t offset, size_t length) override;
virtual bool use_direct_io() const override { return use_direct_io_; }
};
class PosixWritableFile : public WritableFile {
protected:
const std::string filename_;
const bool use_direct_io_;
int fd_;
uint64_t filesize_;
#ifdef ROCKSDB_FALLOCATE_PRESENT
bool allow_fallocate_;
bool fallocate_with_keep_size_;
#endif
public:
explicit PosixWritableFile(const std::string& fname, int fd,
const EnvOptions& options);
virtual ~PosixWritableFile();
// Means Close() will properly take care of truncate
// and it does not need any additional information
virtual Status Truncate(uint64_t size) override { return Status::OK(); }
virtual Status Close() override;
virtual Status Append(const Slice& data) override;
virtual Status PositionedAppend(const Slice& data, uint64_t offset) override;
virtual Status Flush() override;
virtual Status Sync() override;
virtual Status Fsync() override;
virtual bool IsSyncThreadSafe() const override;
virtual bool use_direct_io() const override { return use_direct_io_; }
virtual uint64_t GetFileSize() override;
virtual size_t GetRequiredBufferAlignment() const override {
// TODO(gzh): It should be the logical sector size/filesystem block size
// hardcoded as 4k for most cases
return 4 * 1024;
}
virtual Status InvalidateCache(size_t offset, size_t length) override;
#ifdef ROCKSDB_FALLOCATE_PRESENT
virtual Status Allocate(uint64_t offset, uint64_t len) override;
#endif
#ifdef OS_LINUX
virtual Status RangeSync(uint64_t offset, uint64_t nbytes) override;
virtual size_t GetUniqueId(char* id, size_t max_size) const override;
#endif
};
// mmap() based random-access
class PosixMmapReadableFile : public RandomAccessFile {
private:
int fd_;
std::string filename_;
void* mmapped_region_;
size_t length_;
public:
PosixMmapReadableFile(const int fd, const std::string& fname, void* base,
size_t length, const EnvOptions& options);
virtual ~PosixMmapReadableFile();
virtual Status Read(uint64_t offset, size_t n, Slice* result,
char* scratch) const override;
virtual Status InvalidateCache(size_t offset, size_t length) override;
};
class PosixMmapFile : public WritableFile {
private:
std::string filename_;
int fd_;
size_t page_size_;
size_t map_size_; // How much extra memory to map at a time
char* base_; // The mapped region
char* limit_; // Limit of the mapped region
char* dst_; // Where to write next (in range [base_,limit_])
char* last_sync_; // Where have we synced up to
uint64_t file_offset_; // Offset of base_ in file
#ifdef ROCKSDB_FALLOCATE_PRESENT
bool allow_fallocate_; // If false, fallocate calls are bypassed
bool fallocate_with_keep_size_;
#endif
// Roundup x to a multiple of y
static size_t Roundup(size_t x, size_t y) { return ((x + y - 1) / y) * y; }
size_t TruncateToPageBoundary(size_t s) {
s -= (s & (page_size_ - 1));
assert((s % page_size_) == 0);
return s;
}
Status MapNewRegion();
Status UnmapCurrentRegion();
Status Msync();
public:
PosixMmapFile(const std::string& fname, int fd, size_t page_size,
const EnvOptions& options);
~PosixMmapFile();
// Means Close() will properly take care of truncate
// and it does not need any additional information
virtual Status Truncate(uint64_t size) override { return Status::OK(); }
virtual Status Close() override;
virtual Status Append(const Slice& data) override;
virtual Status Flush() override;
virtual Status Sync() override;
virtual Status Fsync() override;
virtual uint64_t GetFileSize() override;
virtual Status InvalidateCache(size_t offset, size_t length) override;
#ifdef ROCKSDB_FALLOCATE_PRESENT
virtual Status Allocate(uint64_t offset, uint64_t len) override;
#endif
};
class PosixRandomRWFile : public RandomRWFile {
public:
explicit PosixRandomRWFile(const std::string& fname, int fd,
const EnvOptions& options);
virtual ~PosixRandomRWFile();
virtual Status Write(uint64_t offset, const Slice& data) override;
virtual Status Read(uint64_t offset, size_t n, Slice* result,
char* scratch) const override;
virtual Status Flush() override;
virtual Status Sync() override;
virtual Status Fsync() override;
virtual Status Close() override;
private:
const std::string filename_;
int fd_;
};
class PosixDirectory : public Directory {
public:
explicit PosixDirectory(int fd) : fd_(fd) {}
~PosixDirectory();
virtual Status Fsync() override;
private:
int fd_;
};
} // namespace rocksdb