1 files changed, 27 insertions, 4 deletions
diff --git a/cast/streaming/receiver_session.h b/cast/streaming/receiver_session.h
index b448bd00..b29b6d52 100644
--- a/cast/streaming/receiver_session.h
+++ b/cast/streaming/receiver_session.h
@@ -26,7 +26,7 @@ namespace cast {
 class Environment;
 class Receiver;
 
-class ReceiverSession final {
+class ReceiverSession final : public Environment::SocketSubscriber {
  public:
   // Upon successful negotiation, a set of configured receivers is constructed
   // for handling audio and video. Note that either receiver may be null.
@@ -115,20 +115,37 @@ class ReceiverSession final {
 
   const std::string& session_id() const { return session_id_; }
 
+  // Environment::SocketSubscriber event callbacks.
+  void OnSocketReady() override;
+  void OnSocketInvalid(Error error) override;
+
  private:
+  struct SessionProperties {
+    std::unique_ptr<AudioStream> selected_audio;
+    std::unique_ptr<VideoStream> selected_video;
+    int sequence_number;
+
+    // To be valid either the audio or video must be selected, and we must
+    // have a sequence number we can reference.
+    bool IsValid() const;
+  };
+
   // Specific message type handler methods.
   void OnOffer(SenderMessage message);
 
+  // Creates receivers and sends an appropriate Answer message using the
+  // session properties.
+  void InitializeSession(const SessionProperties& properties);
+
   // Used by SpawnReceivers to generate a receiver for a specific stream.
   std::unique_ptr<Receiver> ConstructReceiver(const Stream& stream);
 
   // Creates a set of configured receivers from a given pair of audio and
   // video streams. NOTE: either audio or video may be null, but not both.
-  ConfiguredReceivers SpawnReceivers(const AudioStream* audio,
-                                     const VideoStream* video);
+  ConfiguredReceivers SpawnReceivers(const SessionProperties& properties);
 
   // Callers of this method should ensure at least one stream is non-null.
-  Answer ConstructAnswer(const AudioStream* audio, const VideoStream* video);
+  Answer ConstructAnswer(const SessionProperties& properties);
 
   // Handles resetting receivers and notifying the client.
   void ResetReceivers(Client::ReceiversDestroyingReason reason);
@@ -143,6 +160,12 @@ class ReceiverSession final {
   const std::string session_id_;
   ReceiverSessionMessager messager_;
 
+  // In some cases, the session initialization may be pending waiting for the
+  // UDP socket to be ready. In this case, the receivers and the answer
+  // message will not be configured and sent until the UDP socket has finished
+  // binding.
+  std::unique_ptr<SessionProperties> pending_session_;
+
   bool supports_wifi_status_reporting_ = false;
   ReceiverPacketRouter packet_router_;