media: add video capture device for ARC++ camera HAL v3

media/capture/video/chromeos/camera_hal_delegate.h

+// Copyright 2017 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 MEDIA_CAPTURE_VIDEO_CHROMEOS_CAMERA_HAL_DELEGATE_H_
+#define MEDIA_CAPTURE_VIDEO_CHROMEOS_CAMERA_HAL_DELEGATE_H_
+
+#include "base/macros.h"
+#include "base/synchronization/waitable_event.h"
+#include "base/threading/thread.h"
+#include "media/capture/video/chromeos/mojo/arc_camera3.mojom.h"
+#include "media/capture/video/video_capture_device_factory.h"
+#include "media/capture/video_capture_types.h"
+#include "mojo/public/cpp/bindings/binding.h"
+
+namespace media {
+
+// VideoCaptureDeviceFactoryChromeOS delegates all its VCD factory interface
+// function calls to CameraHalDelegate.
+
+class CAPTURE_EXPORT CameraHalDelegate final
+    : public base::RefCountedThreadSafe<CameraHalDelegate>,
+      public arc::mojom::CameraModuleCallbacks {
+ public:
+  CameraHalDelegate(
+      const scoped_refptr<base::SingleThreadTaskRunner> module_task_runner);
+
+  // Establishes the Mojo IPC channel to the camera HAL adapter.  This method
+  // should be called before any other methods of CameraHalDelegate is called.
+  // Called by VideoCaptureDeviceFactoryChromeOS::Init on the browser IO thread.
+  bool StartCameraModuleIpc();
+
+  // Delegation methods for the VideoCaptureDeviceFactory interface.  These
+  // methods are called by VideoCaptureDeviceFactoryChromeOS directly.  They
+  // operate on the same thread that the VideoCaptureDeviceFactoryChromeOS runs
+  // on.
+  std::unique_ptr<VideoCaptureDevice> CreateDevice(
+      const scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner,
+      const VideoCaptureDeviceDescriptor& device_descriptor);
+  void GetSupportedFormats(
+      const VideoCaptureDeviceDescriptor& device_descriptor,
+      VideoCaptureFormats* supported_formats);
+  void GetDeviceDescriptors(VideoCaptureDeviceDescriptors* device_descriptors);
+
+  // Synchronous method to get the camera info of |camera_id|.  This method may
+  // be called on any thread.
+  using GetCameraInfoCallback =
+      base::Callback<void(int32_t, arc::mojom::CameraInfoPtr)>;
+  void GetCameraInfo(int32_t camera_id, const GetCameraInfoCallback& callback);
+
+  // Asynchronous method to open the camera device desginated by |camera_id|.

[wuchengli, 2017/04/28 06:29:28]

designated

[jcliang, 2017/04/28 08:27:49]

Done.

+  // This method may be called on any thread; |callback| will run on
+  // |module_task_runner_|.
+  using OpenDeviceCallback =
+      base::Callback<void(int32_t, arc::mojom::Camera3DeviceOpsPtr)>;
+  void OpenDevice(int32_t camera_id, const OpenDeviceCallback& callback);
+
+ private:
+  friend class base::RefCountedThreadSafe<CameraHalDelegate>;
+
+  ~CameraHalDelegate();
+
+  // Resets the Mojo interface and bindings.
+  void ResetMojoInterfaceOnModuleThread(base::WaitableEvent* interface_closed);
+
+  // Internal method to attempt to update the camera info for all cameras.
+  // Runs on the same thread as CreateDevice, GetSupportedFormats, and
+  // GetDeviceDescriptors.  This is the only entry point to update
+  // |num_cameras_| and |camera_info_|.
+  bool UpdateCameraInfo();
+
+  // The actual methods that update the camera info.  These methods run on
+  // |module_task_runner_|.
+  void UpdateCameraInfoOnModuleThread();
+  void OnGotNumberOfCamerasOnModuleThread(int32_t num_cameras);
+  void GetCameraInfoOnModuleThread(int32_t camera_id,
+                                   const GetCameraInfoCallback& callback);
+  void OnGotCameraInfoOnModuleThread(int32_t camera_id,
+                                     int32_t result,
+                                     arc::mojom::CameraInfoPtr camera_info);
+
+  // Signaled when |num_cameras_| and |camera_info_| are updated. Queried and
+  // waited by UpdateCameraInfo, signaled by OnGotCameraInfoOnModuleThread, and
+  // reset by CameraDeviceStatusChange.
+  base::WaitableEvent camera_info_updated_;
+
+  // Indicates if a camera info update is in flight, to prevent issuing
+  // duplicated GetCameraInfo calls to |camera_module_delegate_|.
+  bool updating_camera_info_;
+
+  // |num_cameras_| stores the number of camera devices reported by the camera
+  // HAL, and |camera_info_| stores the camera info of each camera device.
+  // They are modified only on |module_task_runner_|. They are also read in
+  // GetSupportedFormats and GetDeviceDescriptors, in which the access is
+  // sequenced through UpdateCameraInfo and |camera_info_updated_| to avoid race
+  // conditions.
+  uint32_t num_cameras_;
+  std::unordered_map<int32_t, arc::mojom::CameraInfoPtr> camera_info_;
+
+  // Called by OpenDevice to actually open the device specified by |camera_id|.
+  // This method runs on |module_task_runner_|.
+  void OpenDeviceOnModuleThread(int32_t camera_id,
+                                const OpenDeviceCallback& callback);
+
+  // Registers camera HAL module callback functions.  SetCallbacks is called
+  // after GetNumberOfCameras is called for the first time, and before any other
+  // calls to |camera_module_|.  These methods run on |module_task_runner_|.
+  void SetCallbacksOnModuleThread();
+  void OnSetCallbacksOnModuleThread(int32_t result);
+  // Indicates if the module callbacks are successfully registered.
+  bool module_callbacks_registered_;
+
+  // CameraModuleCallbacks implementation. Operates on |module_task_runner_|.
+  void CameraDeviceStatusChange(
+      int32_t camera_id,
+      arc::mojom::CameraDeviceStatus new_status) final;
+
+  base::ThreadChecker thread_checker_;
+
+  // The task runner where all the camera module Mojo communication takes place.
+  const scoped_refptr<base::SingleThreadTaskRunner> module_task_runner_;
+
+  // The Mojo proxy to access the camera module at the remote camera HAL.  Bound
+  // to |module_task_runner_|.
+  arc::mojom::CameraModulePtr camera_module_;
+
+  // The Mojo binding serving the camera module callbacks.  Bound to
+  // |module_task_runner_|.
+  mojo::Binding<arc::mojom::CameraModuleCallbacks> camera_module_callbacks_;
+
+  DISALLOW_COPY_AND_ASSIGN(CameraHalDelegate);
+};
+
+}  // namespace media
+
+#endif  // MEDIA_CAPTURE_VIDEO_CHROMEOS_CAMERA_HAL_DELEGATE_H_