fd_file.h revision 761600567d73b23324ae0251e871c15d6849ffd8 
1/*
2 * Copyright (C) 2009 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#ifndef BASE_UNIX_FILE_FD_FILE_H_
18#define BASE_UNIX_FILE_FD_FILE_H_
19
20#include <fcntl.h>
21#include <string>
22#include "base/unix_file/random_access_file.h"
23#include "base/macros.h"
24
25namespace unix_file {
26
27// A RandomAccessFile implementation backed by a file descriptor.
28//
29// Not thread safe.
30class FdFile : public RandomAccessFile {
31 public:
32  FdFile();
33  // Creates an FdFile using the given file descriptor. Takes ownership of the
34  // file descriptor. (Use DisableAutoClose to retain ownership.)
35  explicit FdFile(int fd);
36  explicit FdFile(int fd, const std::string& path);
37
38  // Destroys an FdFile, closing the file descriptor if Close hasn't already
39  // been called. (If you care about the return value of Close, call it
40  // yourself; this is meant to handle failure cases and read-only accesses.
41  // Note though that calling Close and checking its return value is still no
42  // guarantee that data actually made it to stable storage.)
43  virtual ~FdFile();
44
45  // Opens file 'file_path' using 'flags' and 'mode'.
46  bool Open(const std::string& file_path, int flags);
47  bool Open(const std::string& file_path, int flags, mode_t mode);
48
49  // RandomAccessFile API.
50  virtual int Close();
51  virtual int64_t Read(char* buf, int64_t byte_count, int64_t offset) const;
52  virtual int SetLength(int64_t new_length);
53  virtual int64_t GetLength() const;
54  virtual int64_t Write(const char* buf, int64_t byte_count, int64_t offset);
55  virtual int Flush();
56
57  // Bonus API.
58  int Fd() const;
59  bool IsOpened() const;
60  std::string GetPath() const;
61  void DisableAutoClose();
62  bool ReadFully(void* buffer, int64_t byte_count);
63  bool WriteFully(const void* buffer, int64_t byte_count);
64
65 private:
66  int fd_;
67  std::string file_path_;
68  bool auto_close_;
69
70  DISALLOW_COPY_AND_ASSIGN(FdFile);
71};
72
73}  // namespace unix_file
74
75#endif  // BASE_UNIX_FILE_FD_FILE_H_
76