media: add ArcCamera3Service Mojo service

media/capture/video/chromeos/arc_camera3_service.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_ARC_CAMERA3_SERVICE_H_
+#define MEDIA_CAPTURE_VIDEO_CHROMEOS_ARC_CAMERA3_SERVICE_H_
+
+#include <vector>
+
+#include "base/memory/singleton.h"
+#include "base/memory/weak_ptr.h"
+#include "base/single_thread_task_runner.h"
+#include "base/threading/thread.h"
+#include "media/capture/capture_export.h"
+#include "media/capture/video/chromeos/mojo/arc_camera3_service.mojom.h"
+#include "mojo/edk/embedder/scoped_platform_handle.h"
+#include "mojo/public/cpp/bindings/binding_set.h"
+#include "mojo/public/cpp/bindings/interface_ptr_set.h"
+
+namespace media {
+
+class CAPTURE_EXPORT ArcCamera3Service final
+    : public arc::mojom::ArcCamera3Service {
+ public:
+  class CameraClientObserver
+      : public base::SupportsWeakPtr<CameraClientObserver> {
+   public:
+    virtual void NotifyCameraHalRegistered(
+        arc::mojom::CameraModulePtr camera_module) = 0;
+  };
+
+  static ArcCamera3Service* GetInstance();
+
+  bool Start();
+
+  void AddClientObserver(std::unique_ptr<CameraClientObserver> observer);
+
+  bool is_started() {
+    return proxy_thread_.IsRunning() && blocking_io_thread_.IsRunning();
+  }
+
+ private:
+  // A WeakPtr wrapper class around arc::mojom::ArcCamera3HalPtr.
+  class CameraHal : public base::SupportsWeakPtr<CameraHal> {
+   public:
+    explicit CameraHal(arc::mojom::ArcCamera3HalPtr camera_hal);
+
+    void OpenCameraHal(arc::mojom::CameraModuleRequest camera_module_request);
+
+   private:
+    arc::mojom::ArcCamera3HalPtr camera_hal_;
+    DISALLOW_IMPLICIT_CONSTRUCTORS(CameraHal);
+  };
+
+  friend base::DefaultSingletonTraits<ArcCamera3Service>;
+
+  ArcCamera3Service();
+  ~ArcCamera3Service();
+
+  // Creates the unix domain socket for the camera client processes and the
+  // camera HALv3 adapter process to connect.
+  void CreateSocket();
+
+  void CreateServiceLoop(mojo::edk::ScopedPlatformHandle socket_fd);
+
+  // Waits for incoming connections (from HAL process or from client processes).
+  // Runs on |blocking_io_thread_|.
+  void WaitForIncomingConnection(base::ScopedFD cancel_fd);
+
+  // ArcCamera3Service implementations.
+  void RegisterCameraHal(arc::mojom::ArcCamera3HalPtr camera_hal) final;
+  void RegisterClient(arc::mojom::ArcCamera3ClientPtr client) final;
+
+  void AddClientObserverOnProxyThread(
+      std::unique_ptr<CameraClientObserver> observer);
+
+  // Handler for incoming Mojo connection on the unix domain socket.
+  void OnPeerConnected(mojo::ScopedMessagePipeHandle message_pipe);
+
+  // Mojo connection error handlers.
+  void OnCameraHalConnectionError();
+  void OnMojoClientConnectionError(CameraClientObserver* client);
+
+  void StopOnProxyThread();
+
+  mojo::edk::ScopedPlatformHandle proxy_fd_;
+  base::ScopedFD cancel_pipe_;
+
+  base::Thread proxy_thread_;
+  base::Thread blocking_io_thread_;
+  scoped_refptr<base::SingleThreadTaskRunner> proxy_task_runner_;
+  scoped_refptr<base::SingleThreadTaskRunner> blocking_io_task_runner_;
+
+  std::vector<std::unique_ptr<mojo::Binding<arc::mojom::ArcCamera3Service>>>
+      bindings_;
+
+  std::unique_ptr<CameraHal> camera_hal_;
+
+  std::set<std::unique_ptr<CameraClientObserver>> client_observers_;
+
+  DISALLOW_COPY_AND_ASSIGN(ArcCamera3Service);
+};
+
+}  // namespace media
+
+#endif  // MEDIA_CAPTURE_VIDEO_CHROMEOS_ARC_CAMERA3_SERVICE_H_