[Media Galleries] Add an ImageCaptureCore listener for Mac. (part 2)

chrome/browser/system_monitor/image_capture_camera.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_SYSTEM_MONITOR_IMAGE_CAPTURE_CAMERA_H_
+#define CHROME_BROWSER_SYSTEM_MONITOR_IMAGE_CAPTURE_CAMERA_H_
+
+#import <Foundation/Foundation.h>
+#import <ImageCaptureCore/ImageCaptureCore.h>
+
+#include "base/file_path.h"
+#include "base/mac/cocoa_protocols.h"
+#include "base/mac/foundation_util.h"
+#include "base/memory/scoped_nsobject.h"
+#include "base/memory/weak_ptr.h"
+#include "base/platform_file.h"
+#include "base/string_util.h"
+#include "base/sys_string_conversions.h"
+
+// Client's use this listener interface to get notifications about
+// events happening as a particular ImageCapture device is interacted with.
+// Clients drive the interaction through the ImageCaptureDeviceBrowserMac
+// and the ImageCaptureCameraInterface classes, and get notifications of
+// events through this interface.
+class ImageCaptureDeviceListener {
+ public:
+  virtual ~ImageCaptureDeviceListener() {}
+
+  // Get a notification that a particular item has been found on the device.
+  // These calls will come automatically after a new device is initialized.
+  virtual void ItemAdded(const std::string& name,
+                         const base::PlatformFileInfo& info) = 0;
+
+  // Called when there are no more items to retrieve.
+  virtual void NoMoreItems() = 0;
+
+  // Called upon completion of a file download request. The |path| is the
+  // requested download file. Note: in NOT_FOUND error case, can be called
+  // inline with the download request.
+  virtual void DownloadedFile(const std::string& name,
+                              base::PlatformFileError error) = 0;
+
+  // Called to let the client know the device is removed.
+  virtual void DeviceRemoved() = 0;
+};
+
+// Interface to a camera device found by ImageCaptureCore. This class manages a
+// session to the camera and provides the backing interactions to present the
+// media files on it to the filesystem delegate. FilePaths will be artificial,
+// like "/$device_id/" + name.
+// Note on thread-safety. This class ends up involving three different threads.
+// The client is expected to interact with setting up and tearing down the
+// implementation within a single thread context which allows blocking
+// (likely the browser blocking pool). The class is thread-compatible with that
+// usage. It receives events from the ImageCaptureCore library on the UI thread,
+// and will forward callbacks to the listener on that thread. It also uses the
+// File thread for renaming files when necessary.
+// In other words, setup and teardown need to be threaded, and for other
+// interactions the caller needs to be thread-safe.
+@interface ImageCaptureCameraInterface
+    : NSObject<ICCameraDeviceDelegate, ICCameraDeviceDownloadDelegate> {
+ @private
+  scoped_nsobject<ICCameraDevice> camera_;
+  base::WeakPtr<ImageCaptureDeviceListener> listener_;
+}
+
+- (id)initWithCameraDevice:(ICCameraDevice*)cameraDevice;
+- (void)open;
+- (void)close;
+- (void)setListener:(base::WeakPtr<ImageCaptureDeviceListener>)listener;
+
+// Download the given |file| to the provided |local_path|. Completion notice
+// will be sent to the listener's DownloadedFile method.
+- (void)downloadFile:(const std::string&)name
+           localPath:(const FilePath&)localPath;
+
+@end
+
+#endif  // CHROME_BROWSER_SYSTEM_MONITOR_IMAGE_CAPTURE_CAMERA_H_