CmaMediaPipelineClient to watch media pipeline status

chromecast/base/cast_resource.h

+// Copyright 2015 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 CHROMECAST_BASE_CAST_RESOURCE_H_
+#define CHROMECAST_BASE_CAST_RESOURCE_H_
+
+#include "base/macros.h"
+
+namespace chromecast {
+
+// Interface for resources needed to run application.
+class CastResource {
+ public:
+  // Resources necessary to run cast apps. CastResource may contain union of the
+  // following types.
+  // TODO(yucliu): Split video resources and graphic resources.
+  enum Resource {
+    kResourceNone = 0,
+    // All resources necessary to render sounds, for example, audio pipeline,
+    // speaker, etc.
+    kResourceAudio = 1 << 0,
+    // All resources necessary to render videos or images, for example, video
+    // pipeline, primary graphics plane, display, etc.
+    kResourceScreenPrimary = 1 << 1,
+    // All resources necessary to render overlaid images, for example, secondary
+    // graphics plane, LCD, etc.
+    kResourceScreenSecondary = 1 << 2,
+    // Collection of resources used for display only combined with bitwise or.
+    kResourceDisplayOnly = (kResourceScreenPrimary | kResourceScreenSecondary),
+    // Collection of all resources combined with bitwise or.
+    kResourceAll =
+        (kResourceAudio | kResourceScreenPrimary | kResourceScreenSecondary),
+  };
+
+  class Client {
+   public:
+    // Called when resource is created. CastResource should not be owned by
+    // Client. It can be called from any thread.
+    virtual void OnResourceAcquired(CastResource* cast_resource) = 0;
+    // Called when part or all resources are released. It can be called from any
+    // thread.
+    //   |cast_resource| the CastResource that is released. The pointer may be
+    //                   invalid. Client can't call functions with that pointer.
+    //   |remain| the unreleased resource of CastResource. If kResourceNone is
+    //            returned, Client will remove the resource from its watching
+    //            list.
+    virtual void OnResourceReleased(CastResource* cast_resource,
+                                    Resource remain) = 0;
+
+   protected:
+    virtual ~Client() {}
+  };
+
+  CastResource() {}
+
+  virtual void SetCastResourceClient(Client* client) = 0;
+  // Called to release resources. Implementation should call
+  // Client::OnResourceReleased when resource is released on its side.
+  virtual void ReleaseResource(Resource resource) = 0;
+
+ protected:
+  virtual ~CastResource() {}
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(CastResource);
+};
+
+}  // namespace chromecast
+
+#endif