chrome/browser/media_galleries/fileapi/mtp_device_async_delegate.h

   1 // Copyright (c) 2013 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 CHROME_BROWSER_MEDIA_GALLERIES_FILEAPI_MTP_DEVICE_ASYNC_DELEGATE_H_
   6 #define CHROME_BROWSER_MEDIA_GALLERIES_FILEAPI_MTP_DEVICE_ASYNC_DELEGATE_H_
   7
   8 #include "base/callback.h"
   9 #include "base/files/file.h"
  10 #include "base/memory/ref_counted.h"
  11 #include "webkit/browser/fileapi/async_file_util.h"
  12
  13 namespace base {
  14 class FilePath;
  15 }
  16
  17 namespace net {
  18 class IOBuffer;
  19 }
  20
  21 // Asynchronous delegate for media transfer protocol (MTP) device to perform
  22 // media device isolated file system operations. Class that implements this
  23 // delegate does the actual communication with the MTP device.
  24 // The lifetime of the delegate is managed by the MTPDeviceMapService class.
  25 // Member functions and callbacks run on the IO thread.
  26 class MTPDeviceAsyncDelegate {
  27  public:
  28   // A callback to be called when GetFileInfo method call succeeds.
  29   typedef base::Callback<
  30       void(const base::File::Info& file_info)> GetFileInfoSuccessCallback;
  31
  32   // A callback to be called when ReadDirectory method call succeeds.
  33   typedef base::Callback<
  34       void(const fileapi::AsyncFileUtil::EntryList& file_list,
  35            bool has_more)> ReadDirectorySuccessCallback;
  36
  37   // A callback to be called when GetFileInfo/ReadDirectory/CreateSnapshot
  38   // method call fails.
  39   typedef base::Callback<void(base::File::Error error)> ErrorCallback;
  40
  41   // A callback to be called when CreateSnapshotFile method call succeeds.
  42   typedef base::Callback<
  43       void(const base::File::Info& file_info,
  44            const base::FilePath& local_path)> CreateSnapshotFileSuccessCallback;
  45
  46   // A callback to be called when ReadBytes method call succeeds.
  47   typedef base::Callback<void(int)> ReadBytesSuccessCallback;
  48
  49   struct ReadBytesRequest {
  50     ReadBytesRequest(const std::string& device_file_relative_path,
  51                      net::IOBuffer* buf, int64 offset, int buf_len,
  52                      const ReadBytesSuccessCallback& success_callback,
  53                      const ErrorCallback& error_callback);
  54     ~ReadBytesRequest();
  55
  56     std::string device_file_relative_path;
  57     scoped_refptr<net::IOBuffer> buf;
  58     int64 offset;
  59     int buf_len;
  60     ReadBytesSuccessCallback success_callback;
  61     ErrorCallback error_callback;
  62   };
  63
  64   // Gets information about the given |file_path| and invokes the appropriate
  65   // callback asynchronously when complete.
  66   virtual void GetFileInfo(
  67       const base::FilePath& file_path,
  68       const GetFileInfoSuccessCallback& success_callback,
  69       const ErrorCallback& error_callback) = 0;
  70
  71   // Enumerates the |root| directory contents and invokes the appropriate
  72   // callback asynchronously when complete.
  73   virtual void ReadDirectory(
  74       const base::FilePath& root,
  75       const ReadDirectorySuccessCallback& success_callback,
  76       const ErrorCallback& error_callback) = 0;
  77
  78   // Copy the contents of |device_file_path| to |local_path|. Invokes the
  79   // appropriate callback asynchronously when complete.
  80   virtual void CreateSnapshotFile(
  81       const base::FilePath& device_file_path,
  82       const base::FilePath& local_path,
  83       const CreateSnapshotFileSuccessCallback& success_callback,
  84       const ErrorCallback& error_callback) = 0;
  85
  86   // Platform-specific implementations that are streaming don't create a local
  87   // snapshot file. Blobs are instead FileSystemURL backed and read in a stream.
  88   virtual bool IsStreaming() = 0;
  89
  90   // Reads up to |buf_len| bytes from |device_file_path| into |buf|. Invokes the
  91   // appropriate callback asynchronously when complete. Only valid when
  92   // IsStreaming() is true.
  93   virtual void ReadBytes(
  94       const base::FilePath& device_file_path,
  95       net::IOBuffer* buf, int64 offset, int buf_len,
  96       const ReadBytesSuccessCallback& success_callback,
  97       const ErrorCallback& error_callback) = 0;
  98
  99   // Called when the
 100   // (1) Browser application is in shutdown mode (or)
 101   // (2) Last extension using this MTP device is destroyed (or)
 102   // (3) Attached MTP device is removed (or)
 103   // (4) User revoked the MTP device gallery permission.
 104   // Ownership of |MTPDeviceAsyncDelegate| is handed off to the delegate
 105   // implementation class by this call. This function should take care of
 106   // cancelling all the pending tasks before deleting itself.
 107   virtual void CancelPendingTasksAndDeleteDelegate() = 0;
 108
 109  protected:
 110   // Always destruct this object via CancelPendingTasksAndDeleteDelegate().
 111   virtual ~MTPDeviceAsyncDelegate() {}
 112 };
 113
 114 typedef base::Callback<void(MTPDeviceAsyncDelegate*)>
 115     CreateMTPDeviceAsyncDelegateCallback;
 116
 117 void CreateMTPDeviceAsyncDelegate(
 118     const base::FilePath::StringType& device_location,
 119     const CreateMTPDeviceAsyncDelegateCallback& callback);
 120
 121 #endif  // CHROME_BROWSER_MEDIA_GALLERIES_FILEAPI_MTP_DEVICE_ASYNC_DELEGATE_H_