base/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_FILE_UTIL_PROXY_H_
   6 #define BASE_FILE_UTIL_PROXY_H_
   7
   8 #include "base/base_export.h"
   9 #include "base/callback_forward.h"
  10 #include "base/file_path.h"
  11 #include "base/file_util.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   static bool CreateOrOpen(TaskRunner* task_runner,
  63                            const FilePath& file_path,
  64                            int file_flags,
  65                            const CreateOrOpenCallback& callback);
  66
  67   // Creates a temporary file for writing. The path and an open file handle are
  68   // returned. It is invalid to pass a null callback. The additional file flags
  69   // will be added on top of the default file flags which are:
  70   //   base::PLATFORM_FILE_CREATE_ALWAYS
  71   //   base::PLATFORM_FILE_WRITE
  72   //   base::PLATFORM_FILE_TEMPORARY.
  73   // Set |additional_file_flags| to 0 for synchronous writes and set to
  74   // base::PLATFORM_FILE_ASYNC to support asynchronous file operations.
  75   static bool CreateTemporary(
  76       TaskRunner* task_runner,
  77       int additional_file_flags,
  78       const CreateTemporaryCallback& callback);
  79
  80   // Close the given file handle.
  81   static bool Close(TaskRunner* task_runner,
  82                     PlatformFile,
  83                     const StatusCallback& callback);
  84
  85   // Retrieves the information about a file. It is invalid to pass a null
  86   // callback.
  87   static bool GetFileInfo(
  88       TaskRunner* task_runner,
  89       const FilePath& file_path,
  90       const GetFileInfoCallback& callback);
  91
  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   static bool Delete(TaskRunner* task_runner,
 100                      const FilePath& file_path,
 101                      bool recursive,
 102                      const StatusCallback& callback);
 103
 104   // Deletes a directory and all of its contents.
 105   static bool RecursiveDelete(
 106       TaskRunner* task_runner,
 107       const FilePath& file_path,
 108       const StatusCallback& callback);
 109
 110   // Reads from a file. On success, the file pointer is moved to position
 111   // |offset + bytes_to_read| in the file. The callback can be null.
 112   static bool Read(
 113       TaskRunner* task_runner,
 114       PlatformFile file,
 115       int64 offset,
 116       int bytes_to_read,
 117       const ReadCallback& callback);
 118
 119   // Writes to a file. If |offset| is greater than the length of the file,
 120   // |false| is returned. On success, the file pointer is moved to position
 121   // |offset + bytes_to_write| in the file. The callback can be null.
 122   // |bytes_to_write| must be greater than zero.
 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   static bool Touch(
 133       TaskRunner* task_runner,
 134       PlatformFile file,
 135       const Time& last_access_time,
 136       const Time& last_modified_time,
 137       const StatusCallback& callback);
 138
 139   // Touches a file. The callback can be null.
 140   static bool Touch(
 141       TaskRunner* task_runner,
 142       const FilePath& file_path,
 143       const Time& last_access_time,
 144       const Time& last_modified_time,
 145       const StatusCallback& callback);
 146
 147   // Truncates a file to the given length. If |length| is greater than the
 148   // current length of the file, the file will be extended with zeroes.
 149   // The callback can be null.
 150   static bool Truncate(
 151       TaskRunner* task_runner,
 152       PlatformFile file,
 153       int64 length,
 154       const StatusCallback& callback);
 155
 156   // Truncates a file to the given length. If |length| is greater than the
 157   // current length of the file, the file will be extended with zeroes.
 158   // The callback can be null.
 159   static bool Truncate(
 160       TaskRunner* task_runner,
 161       const FilePath& path,
 162       int64 length,
 163       const StatusCallback& callback);
 164
 165   // Flushes a file. The callback can be null.
 166   static bool Flush(
 167       TaskRunner* task_runner,
 168       PlatformFile file,
 169       const StatusCallback& callback);
 170
 171   // Relay helpers.
 172   static bool RelayFileTask(
 173       TaskRunner* task_runner,
 174       const tracked_objects::Location& from_here,
 175       const FileTask& task,
 176       const StatusCallback& callback);
 177
 178   static bool RelayCreateOrOpen(
 179       TaskRunner* task_runner,
 180       const CreateOrOpenTask& open_task,
 181       const CloseTask& close_task,
 182       const CreateOrOpenCallback& callback);
 183
 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_FILE_UTIL_PROXY_H_