base/files/file_util_proxy.h

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