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