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