WebRtcMediaStreamAdapterMap added.

content/renderer/media/webrtc/webrtc_media_stream_adapter_map.h

+// Copyright (c) 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 CONTENT_RENDERER_MEDIA_WEBRTC_WEBRTC_MEDIA_STREAM_ADAPTER_MAP_H_
+#define CONTENT_RENDERER_MEDIA_WEBRTC_WEBRTC_MEDIA_STREAM_ADAPTER_MAP_H_
+
+#include "base/memory/ref_counted.h"
+#include "base/single_thread_task_runner.h"
+#include "content/common/content_export.h"
+#include "content/renderer/media/webrtc/webrtc_media_stream_adapter.h"
+#include "third_party/WebKit/public/platform/WebMediaStream.h"
+#include "third_party/webrtc/api/mediastreaminterface.h"
+
+namespace content {
+
+// A map and owner of |WebRtcMediaStreamAdapter|s. Adapters are the glue between
+// blink and webrtc layer versions of streams. As long as a stream is in use by
+// a peer connection there has to exist an adapter for it. The map takes care of
+// creating and disposing stream adapters. Adapters are accessed via
+// |AdapterRef|s, when all references to an adapter are destroyed it is
+// destroyed and removed from the map.
+class CONTENT_EXPORT WebRtcMediaStreamAdapterMap
+    : public base::RefCountedThreadSafe<WebRtcMediaStreamAdapterMap> {
+ private:
+  // The map's entries are reference counted in order to remove the adapter when
+  // all |AdapterRef|s referencing an entry are destroyed.
+  // Private section needed here due to |AdapterRef|'s usage of |AdapterEntry|.
+  struct AdapterEntry {
+    AdapterEntry(std::unique_ptr<WebRtcMediaStreamAdapter> adapter);
+    AdapterEntry(AdapterEntry&& other);
+    ~AdapterEntry();
+
+    AdapterEntry(const AdapterEntry&) = delete;
+    AdapterEntry& operator=(const AdapterEntry&) = delete;
+
+    std::unique_ptr<WebRtcMediaStreamAdapter> adapter;
+    size_t ref_count;
+  };
+
+ public:
+  // Accessor to an adapter to take care of reference counting. When the last
+  // |AdapterRef| is destroyed, the corresponding adapter is destroyed and
+  // removed from the map.
+  class CONTENT_EXPORT AdapterRef {
+   public:
+    // Must be invoked on the main thread. If this was the last reference to the
+    // adapter it will be disposed and removed from the map.
+    ~AdapterRef();
+
+    const WebRtcMediaStreamAdapter& adapter() const {
+      return *it_->second.adapter;
+    }
+
+   private:
+    friend class WebRtcMediaStreamAdapterMap;
+    using MapEntryIterator = std::map<std::string, AdapterEntry>::iterator;
+
+    // Increments the |AdapterEntry::ref_count|.
+    AdapterRef(scoped_refptr<WebRtcMediaStreamAdapterMap> map,
+               const MapEntryIterator& it);
+
+    AdapterEntry* entry() { return &it_->second; }
+
+    scoped_refptr<WebRtcMediaStreamAdapterMap> map_;
+    MapEntryIterator it_;
+  };
+
+  // Must be invoked on the main thread.
+  WebRtcMediaStreamAdapterMap(
+      PeerConnectionDependencyFactory* const factory,
+      scoped_refptr<WebRtcMediaStreamTrackAdapterMap> track_adapter_map);
+
+  // Invoke on the main thread. Gets a new reference to the local stream adapter
+  // by ID, or null if no such adapter was found. When all references are
+  // destroyed the adapter is destroyed and removed from the map. References
+  // must be destroyed on the main thread.
+  std::unique_ptr<AdapterRef> GetLocalStreamAdapter(const std::string& id);
+  // Invoke on the main thread. Gets a new reference to the local stream adapter
+  // for the web stream. If no adapter exists for the stream one is created.
+  // When all references are destroyed the adapter is destroyed and removed from
+  // the map. References must be destroyed on the main thread.
+  std::unique_ptr<AdapterRef> GetOrCreateLocalStreamAdapter(
+      const blink::WebMediaStream& web_stream);
+  // Invoke on the main thread.
+  size_t GetLocalStreamCount() const;
+
+ protected:
+  friend class base::RefCountedThreadSafe<WebRtcMediaStreamAdapterMap>;
+
+  // Invoke on the main thread.
+  virtual ~WebRtcMediaStreamAdapterMap();
+
+ private:
+  // Pointer to a |PeerConnectionDependencyFactory| owned by the |RenderThread|.
+  // It's valid for the lifetime of |RenderThread|.
+  PeerConnectionDependencyFactory* const factory_;
+  scoped_refptr<base::SingleThreadTaskRunner> main_thread_;
+  // Takes care of creating and owning track adapters, used by stream adapters.
+  scoped_refptr<WebRtcMediaStreamTrackAdapterMap> track_adapter_map_;
+
+  std::map<std::string, AdapterEntry> local_stream_adapters_;
+  // TODO(hbos): Take care of remote stream adapters as well. This will require
+  // usage of the signaling thread. crbug.com/705901
+};
+
+}  // namespace content
+
+#endif  // CONTENT_RENDERER_MEDIA_WEBRTC_WEBRTC_MEDIA_STREAM_ADAPTER_MAP_H_