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

media/capture/video/chromeos/stream_buffer_manager.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_STREAM_BUFFER_MANAGER_H_
+#define MEDIA_CAPTURE_VIDEO_CHROMEOS_STREAM_BUFFER_MANAGER_H_
+
+#include "base/memory/shared_memory.h"
+#include "media/capture/video/chromeos/mojo/arc_camera3.mojom.h"
+#include "media/capture/video_capture_types.h"
+#include "mojo/public/cpp/bindings/binding.h"
+
+namespace media {
+
+class CameraDeviceContext;
+class CameraDeviceDelegate;
+
+// StreamBufferManager is responsible for managing the buffers of the
+// stream.  StreamBufferManager allocates buffers according to the given
+// stream configuration, and circulates the buffers along with capture
+// requests and results between Chrome and the camera HAL process.
+class CAPTURE_EXPORT StreamBufferManager final
+    : public base::RefCountedThreadSafe<StreamBufferManager>,
+      public arc::mojom::Camera3CallbackOps {
+ public:
+  StreamBufferManager(
+      arc::mojom::Camera3CallbackOpsRequest callback_ops_request,
+      scoped_refptr<CameraDeviceDelegate> camera_device_delegate,
+      CameraDeviceContext* device_context,
+      scoped_refptr<base::SingleThreadTaskRunner> ipc_task_runner);
+
+  // Sets up the stream context and allocate buffers according to the
+  // configuration specified in |stream|.
+  void SetUpStreamAndBuffers(VideoCaptureFormat capture_format,
+                             uint32_t partial_result_count,
+                             arc::mojom::Camera3StreamPtr stream);
+
+  // StartCapture is the entry point to starting the video capture.  The way
+  // the video capture loop works is:
+  //
+  //  (1) If there is a free buffer, RegisterBuffer registers the buffer with
+  //      the camera HAL.
+  //  (2) Once the free buffer is registered, ProcessCaptureRequest is called
+  //      to issue a capture request which will eventually fill the registered
+  //      buffer.  Goto (1) to register the remaining free buffers.
+  //  (3) The camera HAL returns the shutter time of a capture request through
+  //      Notify, and the filled buffer through ProcessCaptureResult.
+  //  (4) Once all the result metadata are collected, SubmitCaptureResult is
+  //      called to deliver the filled buffer to Chrome.  After the buffer is
+  //      consumed by Chrome it is enqueued back to the free buffer queue.
+  //      Goto (1) to start another capture loop.
+  void StartCapture(arc::mojom::CameraMetadataPtr settings);
+
+  // Stops the capture loop.  After StopCapture is called |callback_ops_| is
+  // unbound, so no new capture request or result will be processed.
+  void StopCapture();
+
+ private:
+  friend class base::RefCountedThreadSafe<StreamBufferManager>;
+  ~StreamBufferManager() = default;
+
+  // Registers a free buffer, if any, to the camera HAL.
+  void RegisterBuffer();
+
+  // Calls ProcessCaptureRequest if the buffer specified by |buffer_id| is
+  // successfully registered.
+  void OnRegisteredBuffer(size_t buffer_id, int32_t result);
+
+  // The capture request contains the buffer handle specified by |buffer_id|.
+  void ProcessCaptureRequest(size_t buffer_id);
+  // Calls RegisterBuffer to attempt to register any remaining free buffers.
+  void OnProcessedCaptureRequest(int32_t result);
+
+  // Camera3CallbackOps implementations.
+
+  // ProcessCaptureResult receives the result metadata as well as the filled
+  // buffer from camera HAL.  The result metadata may be divided and delivered
+  // in several stages.  Before all the result metadata is received the
+  // partial results are kept in |partial_results_|.
+  void ProcessCaptureResult(arc::mojom::Camera3CaptureResultPtr result) final;
+
+  // Notify receives the shutter time of capture requests and various errors
+  // from camera HAL.  The shutter time is used as the timestamp in the video
+  // frame delivered to Chrome.
+  void Notify(arc::mojom::Camera3NotifyMsgPtr message) final;
+  void HandleNotifyError(uint32_t frame_number,
+                         uint64_t error_stream_id,
+                         arc::mojom::Camera3ErrorMsgCode error_code);
+
+  // Submits the captured buffer of frame |frame_number_| to Chrome, then
+  // enqueues the buffer to free buffer queue for the next capture request.
+  void SubmitCaptureResult(uint32_t frame_number);
+
+  // Mojo proxy and binding for the camera HAL device ops and callback ops
+  // interfaces.
+  mojo::Binding<arc::mojom::Camera3CallbackOps> callback_ops_;
+
+  // A reference to the CameraDeviceDelegate that owns this
+  // StreamBufferManager instance.
+  const scoped_refptr<CameraDeviceDelegate> camera_device_delegate_;
+
+  CameraDeviceContext* device_context_;
+
+  // Where all the Mojo IPC calls takes place.
+  const scoped_refptr<base::SingleThreadTaskRunner> ipc_task_runner_;
+
+  // A flag indicating whether the capture loops is running.
+  bool capturing_;
+
+  // The frame number.  Increased by one for each capture request sent; reset
+  // to zero in AllocateAndStart.
+  uint32_t frame_number_;
+
+  struct StreamContext {
+    // The actual pixel format used in the capture request.
+    VideoCaptureFormat capture_format;
+    // The camera HAL stream.
+    arc::mojom::Camera3StreamPtr stream;
+    // The request settings used in the capture request of this stream.
+    arc::mojom::CameraMetadataPtr request_settings;
+    // The allocated buffers of this stream.
+    std::vector<std::unique_ptr<base::SharedMemory>> buffers;
+    // The free buffers of this stream.  The queue stores indices into the
+    // |buffers| vector.
+    std::queue<size_t> free_buffers;
+  };
+
+  // The stream context of the preview stream.
+  std::unique_ptr<StreamContext> stream_context_;
+
+  // CaptureResult is used to hold the partial capture results for each frame.
+  struct CaptureResult {
+    CaptureResult() : metadata(arc::mojom::CameraMetadata::New()) {}
+    // |reference_time| and |timestamp| are derived from the shutter time of
+    // this frame.  They are be passed to |client_->OnIncomingCapturedData|
+    // along with the |buffers| when the captured frame is submitted.
+    base::TimeTicks reference_time;
+    base::TimeDelta timestamp;
+    // The result metadata.  Contains various information about the captured
+    // frame.
+    arc::mojom::CameraMetadataPtr metadata;
+    // The buffer handle that hold the captured data of this frame.
+    arc::mojom::Camera3StreamBufferPtr buffer;
+    // The set of the partial metadata received.  For each capture result, the
+    // total number of partial metadata should equal to
+    // |partial_result_count_|.
+    std::set<uint32_t> partial_metadata_received;
+  };
+
+  // The number of partial stages.  |partial_result_count_| is learned by
+  // querying |static_metadata_|.  In case the result count is absent in
+  // |static_metadata_|, it defaults to one which means all the result
+  // metadata and captured buffer of a frame are returned together in one
+  // shot.
+  uint32_t partial_result_count_;
+
+  // The shutter time of the first frame.  We derive the |timestamp| of a
+  // frame using the difference between the frame's shutter time and
+  // |first_frame_shutter_time_|.
+  base::TimeTicks first_frame_shutter_time_;
+
+  // Stores the partial capture results of the current in-flight frames.
+  std::map<uint32_t, CaptureResult> partial_results_;
+
+  DISALLOW_IMPLICIT_CONSTRUCTORS(StreamBufferManager);
+};
+
+}  // namespace media
+
+#endif  // MEDIA_CAPTURE_VIDEO_CHROMEOS_STREAM_BUFFER_MANAGER_H_