[Media Galleries] Filesystem interface for Mac PTP/MTP devices using ImageCaptureCore (part 3)

chrome/browser/media_gallery/mac/mtp_device_delegate_impl_mac.h

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_MEDIA_GALLERY_MTP_DEVICE_DELEGATE_IMPL_MAC_H_
+#define CHROME_BROWSER_MEDIA_GALLERY_MTP_DEVICE_DELEGATE_IMPL_MAC_H_
+
+#include <vector>
+
+#include "base/file_path.h"
+#include "base/hash_tables.h"
+#include "base/memory/weak_ptr.h"
+#include "base/platform_file.h"
+#include "base/sequenced_task_runner_helpers.h"
+#include "base/synchronization/lock.h"
+#include "base/synchronization/waitable_event.h"
+#include "webkit/fileapi/file_system_file_util.h"
+#include "webkit/fileapi/media/mtp_device_delegate.h"
+
+namespace base {
+class SequencedTaskRunner;
+}
+
+namespace chrome {
+
+// Delegate for presenting an Image Capture device through the filesystem
+// API. The synthetic filesystem will be rooted at the constructed location,
+// and names of all files notified through the ItemAdded call will be
+// all appear as children of that directory. (ItemAdded calls with directories
+// will be ignored.)
+class MTPDeviceDelegateImplMac : public fileapi::MTPDeviceDelegate {
+ public:
+  MTPDeviceDelegateImplMac(const std::string& device_id,
+                           const FilePath::StringType& synthetic_path,
+                           base::SequencedTaskRunner* media_task_runner);
+
+  // MTPDeviceDelegate:
+  virtual base::PlatformFileError GetFileInfo(
+      const FilePath& file_path,
+      base::PlatformFileInfo* file_info) OVERRIDE;
+  virtual scoped_ptr<fileapi::FileSystemFileUtil::AbstractFileEnumerator>
+      CreateFileEnumerator(const FilePath& root, bool recursive) OVERRIDE;
+  virtual base::PlatformFileError CreateSnapshotFile(
+      const FilePath& device_file_path,
+      const FilePath& local_path,
+      base::PlatformFileInfo* file_info) OVERRIDE;
+  virtual void CancelPendingTasksAndDeleteDelegate() OVERRIDE;
+
+  // Forward delegates for ImageCaptureDeviceListener
+  virtual void ItemAdded(const std::string& name,
+                         const base::PlatformFileInfo& info);
+  virtual void NoMoreItems();
+  virtual void DownloadedFile(const std::string& name,
+                              base::PlatformFileError error);
+
+  // Implementation returned by |CreateFileEnumerator()|. Must be deleted
+  // before CancelPendingTasksAndDeleteDelegate is called.
+  class Enumerator :
+      public fileapi::FileSystemFileUtil::AbstractFileEnumerator {
+   public:
+    explicit Enumerator(MTPDeviceDelegateImplMac* delegate);
+    virtual ~Enumerator();
+
+    virtual FilePath Next() OVERRIDE;
+    virtual int64 Size() OVERRIDE;
+    virtual base::Time LastModifiedTime() OVERRIDE;
+    virtual bool IsDirectory() OVERRIDE;
+
+    // Called by the delegate to signal any waiters that the received items
+    // list has changed state.
+    void ItemsChanged();
+
+   private:
+    MTPDeviceDelegateImplMac* delegate_;
+    size_t position_;
+    base::WaitableEvent wait_for_items_;
+  };
+
+  // GetFile and HasAllFiles called by enumerators.
+  FilePath GetFile(size_t index);
+  bool ReceivedAllFiles();
+  void RemoveEnumerator(Enumerator* enumerator);
+
+ private:
+  friend class base::DeleteHelper<MTPDeviceDelegateImplMac>;
+
+  class DeviceListener;
+
+  virtual ~MTPDeviceDelegateImplMac();
+
+  std::string device_id_;
+  FilePath root_path_;
+
+  // Stores a reference to worker pool thread. All requests and response of file
+  // operations are posted on |media_task_runner_|. All callbacks from the
+  // camera will come through this task runner as well.
+  scoped_refptr<base::SequencedTaskRunner> media_task_runner_;
+
+  // Interface object for the camera underlying this MTP session.
+  scoped_ptr<DeviceListener> camera_interface_;
+
+  // This lock protects all subsequent state. While calling into the delegate
+  // from the FileSystem API happens in sequence, these calls may be
+  // interleaved with calls on other threads in the sequenced task runner
+  // forwarded from the device.
+  base::Lock mutex_;
+
+  // Weak pointer to the enumerator which may be listening for files to come in.
+  Enumerator* enumerator_;
+
+  // Stores a map from filename to file metadata received from the camera.
+  base::hash_map<FilePath::StringType, base::PlatformFileInfo> file_info_;
+
+  // Notification for pending download.
+  base::WaitableEvent* file_download_event_;
+
+  // Resulting error code for pending download.
+  base::PlatformFileError file_download_error_;
+
+  // List of files received from the camera.
+  std::vector<FilePath> file_paths_;
+
+  // Set to true when all file metadata has been received from the camera.
+  bool received_all_files_;
+
+  DISALLOW_COPY_AND_ASSIGN(MTPDeviceDelegateImplMac);
+};
+
+}  // namespace chrome
+
+#endif  // CHROME_BROWSER_MEDIA_GALLERY_MTP_DEVICE_DELEGATE_IMPL_MAC_H_