file_util_proxy.h revision a93a17c8d99d686bd4a1511e5504e5e6cc9fcadf 
1// Copyright (c) 2012 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef BASE_FILES_FILE_UTIL_PROXY_H_
6#define BASE_FILES_FILE_UTIL_PROXY_H_
7
8#include "base/base_export.h"
9#include "base/callback_forward.h"
10#include "base/files/file_path.h"
11#include "base/memory/ref_counted.h"
12#include "base/platform_file.h"
13
14namespace tracked_objects {
15class Location;
16};
17
18namespace base {
19
20class TaskRunner;
21class Time;
22
23// This class provides asynchronous access to common file routines.
24class BASE_EXPORT FileUtilProxy {
25 public:
26  // Holds metadata for file or directory entry.
27  struct Entry {
28    FilePath::StringType name;
29    bool is_directory;
30    int64 size;
31    base::Time last_modified_time;
32  };
33
34  // This callback is used by methods that report only an error code.  It is
35  // valid to pass a null callback to any function that takes a StatusCallback,
36  // in which case the operation will complete silently.
37  typedef Callback<void(PlatformFileError)> StatusCallback;
38
39  typedef Callback<void(PlatformFileError,
40                        PassPlatformFile,
41                        bool /* created */)> CreateOrOpenCallback;
42  typedef Callback<void(PlatformFileError,
43                        PassPlatformFile,
44                        const FilePath&)> CreateTemporaryCallback;
45  typedef Callback<void(PlatformFileError,
46                        const PlatformFileInfo&)> GetFileInfoCallback;
47  typedef Callback<void(PlatformFileError,
48                        const char* /* data */,
49                        int /* bytes read */)> ReadCallback;
50  typedef Callback<void(PlatformFileError,
51                        int /* bytes written */)> WriteCallback;
52
53  typedef Callback<PlatformFileError(PlatformFile*, bool*)> CreateOrOpenTask;
54  typedef Callback<PlatformFileError(PlatformFile)> CloseTask;
55  typedef Callback<PlatformFileError(void)> FileTask;
56
57  // Creates or opens a file with the given flags. It is invalid to pass a null
58  // callback. If PLATFORM_FILE_CREATE is set in |file_flags| it always tries to
59  // create a new file at the given |file_path| and calls back with
60  // PLATFORM_FILE_ERROR_FILE_EXISTS if the |file_path| already exists.
61  //
62  // This returns false if task posting to |task_runner| has failed.
63  static bool CreateOrOpen(TaskRunner* task_runner,
64                           const FilePath& file_path,
65                           int file_flags,
66                           const CreateOrOpenCallback& callback);
67
68  // Creates a temporary file for writing. The path and an open file handle are
69  // returned. It is invalid to pass a null callback. The additional file flags
70  // will be added on top of the default file flags which are:
71  //   base::PLATFORM_FILE_CREATE_ALWAYS
72  //   base::PLATFORM_FILE_WRITE
73  //   base::PLATFORM_FILE_TEMPORARY.
74  // Set |additional_file_flags| to 0 for synchronous writes and set to
75  // base::PLATFORM_FILE_ASYNC to support asynchronous file operations.
76  //
77  // This returns false if task posting to |task_runner| has failed.
78  static bool CreateTemporary(
79      TaskRunner* task_runner,
80      int additional_file_flags,
81      const CreateTemporaryCallback& callback);
82
83  // Close the given file handle.
84  // This returns false if task posting to |task_runner| has failed.
85  static bool Close(TaskRunner* task_runner,
86                    PlatformFile,
87                    const StatusCallback& callback);
88
89  // Retrieves the information about a file. It is invalid to pass a null
90  // callback.
91  // This returns false if task posting to |task_runner| has failed.
92  static bool GetFileInfo(
93      TaskRunner* task_runner,
94      const FilePath& file_path,
95      const GetFileInfoCallback& callback);
96
97  // Does the same as GetFileInfo but takes PlatformFile instead of FilePath.
98  // This returns false if task posting to |task_runner| has failed.
99  static bool GetFileInfoFromPlatformFile(
100      TaskRunner* task_runner,
101      PlatformFile file,
102      const GetFileInfoCallback& callback);
103
104  // Deletes a file or a directory.
105  // It is an error to delete a non-empty directory with recursive=false.
106  // This returns false if task posting to |task_runner| has failed.
107  static bool Delete(TaskRunner* task_runner,
108                     const FilePath& file_path,
109                     bool recursive,
110                     const StatusCallback& callback);
111
112  // Deletes a directory and all of its contents.
113  // This returns false if task posting to |task_runner| has failed.
114  static bool RecursiveDelete(
115      TaskRunner* task_runner,
116      const FilePath& file_path,
117      const StatusCallback& callback);
118
119  // Reads from a file. On success, the file pointer is moved to position
120  // |offset + bytes_to_read| in the file. The callback can be null.
121  //
122  // This returns false if |bytes_to_read| is less than zero, or
123  // if task posting to |task_runner| has failed.
124  static bool Read(
125      TaskRunner* task_runner,
126      PlatformFile file,
127      int64 offset,
128      int bytes_to_read,
129      const ReadCallback& callback);
130
131  // Writes to a file. If |offset| is greater than the length of the file,
132  // |false| is returned. On success, the file pointer is moved to position
133  // |offset + bytes_to_write| in the file. The callback can be null.
134  // |bytes_to_write| must be greater than zero.
135  //
136  // This returns false if |bytes_to_write| is less than or equal to zero,
137  // if |buffer| is NULL, or if task posting to |task_runner| has failed.
138  static bool Write(
139      TaskRunner* task_runner,
140      PlatformFile file,
141      int64 offset,
142      const char* buffer,
143      int bytes_to_write,
144      const WriteCallback& callback);
145
146  // Touches a file. The callback can be null.
147  // This returns false if task posting to |task_runner| has failed.
148  static bool Touch(
149      TaskRunner* task_runner,
150      PlatformFile file,
151      const Time& last_access_time,
152      const Time& last_modified_time,
153      const StatusCallback& callback);
154
155  // Touches a file. The callback can be null.
156  // This returns false if task posting to |task_runner| has failed.
157  static bool Touch(
158      TaskRunner* task_runner,
159      const FilePath& file_path,
160      const Time& last_access_time,
161      const Time& last_modified_time,
162      const StatusCallback& callback);
163
164  // Truncates a file to the given length. If |length| is greater than the
165  // current length of the file, the file will be extended with zeroes.
166  // The callback can be null.
167  // This returns false if task posting to |task_runner| has failed.
168  static bool Truncate(
169      TaskRunner* task_runner,
170      PlatformFile file,
171      int64 length,
172      const StatusCallback& callback);
173
174  // Truncates a file to the given length. If |length| is greater than the
175  // current length of the file, the file will be extended with zeroes.
176  // The callback can be null.
177  // This returns false if task posting to |task_runner| has failed.
178  static bool Truncate(
179      TaskRunner* task_runner,
180      const FilePath& path,
181      int64 length,
182      const StatusCallback& callback);
183
184  // Flushes a file. The callback can be null.
185  // This returns false if task posting to |task_runner| has failed.
186  static bool Flush(
187      TaskRunner* task_runner,
188      PlatformFile file,
189      const StatusCallback& callback);
190
191  // Relay helpers.
192  // They return false if posting a given task to |task_runner| has failed.
193  static bool RelayCreateOrOpen(
194      TaskRunner* task_runner,
195      const CreateOrOpenTask& open_task,
196      const CloseTask& close_task,
197      const CreateOrOpenCallback& callback);
198  static bool RelayClose(
199      TaskRunner* task_runner,
200      const CloseTask& close_task,
201      PlatformFile,
202      const StatusCallback& callback);
203
204 private:
205  DISALLOW_IMPLICIT_CONSTRUCTORS(FileUtilProxy);
206};
207
208}  // namespace base
209
210#endif  // BASE_FILES_FILE_UTIL_PROXY_H_
211