Add (Video|Audio)Stream to ConfiguredReceivers

Currently, embedders have no way of knowing what stream that libcast
selected, and the SessionConfig class we expose only has a limited set
of fields available, and is missing several important fields, such as
codec.

This patch exposes the AudioStream and VideoStream that were selected,
if any, from the initial offer message on the OnNegotiated callback.

Change-Id: Ia276fb991618a3fb4f8a4cc8c4d77192446397ac
Bug: http://crbug.com/openscreen/97
Reviewed-on: https://chromium-review.googlesource.com/c/openscreen/+/1990358
Reviewed-by: Yuri Wiitala <miu@chromium.org>
Reviewed-by: Ryan Keane <rwkeane@google.com>
Commit-Queue: Jordan Bayles <jophba@chromium.org>

1 files changed, 13 insertions, 27 deletions

diff --git a/cast/streaming/receiver_session.h b/cast/streaming/receiver_session.h
index 72e46385..f57ca278 100644
--- a/cast/streaming/receiver_session.h
+++ b/cast/streaming/receiver_session.h
@@ -27,10 +27,19 @@ class VirtualConnection;
 
 class ReceiverSession final : public MessagePort::Client {
  public:
+  // A small helper struct that contains all of the information necessary for
+  // a configured receiver, including a receiver, its session config, and the
+  // stream selected from the OFFER message to instantiate the receiver.
+  template <typename T>
+  struct ConfiguredReceiver {
+    Receiver* receiver;
+    const SessionConfig receiver_config;
+    const T selected_stream;
+  };
+
   // Upon successful negotiation, a set of configured receivers is constructed
   // for handling audio and video. Note that either receiver may be null.
-  class ConfiguredReceivers {
-   public:
+  struct ConfiguredReceivers {
     // In practice, we may have 0, 1, or 2 receivers configured, depending
     // on if the device supports audio and video, and if we were able to
     // successfully negotiate a receiver configuration.
@@ -39,33 +48,11 @@ class ReceiverSession final : public MessagePort::Client {
     // to be valid until the OnReceiversDestroyed event is fired, at which
     // point they become invalid and need to replaced by the results of
     // the ensuing OnNegotiated call.
-    ConfiguredReceivers(
-        Receiver* audio_receiver,
-        const absl::optional<SessionConfig> audio_receiver_config,
-        Receiver* video_receiver,
-        const absl::optional<SessionConfig> video_receiver_config);
-    ConfiguredReceivers(const ConfiguredReceivers&) = delete;
-    ConfiguredReceivers(ConfiguredReceivers&&) noexcept;
-    ConfiguredReceivers& operator=(const ConfiguredReceivers&) = delete;
-    ConfiguredReceivers& operator=(ConfiguredReceivers&&) noexcept;
-    ~ConfiguredReceivers();
 
     // If the receiver is audio- or video-only, either of the receivers
     // may be nullptr. However, in the majority of cases they will be populated.
-    Receiver* audio_receiver() const { return audio_receiver_; }
-    const absl::optional<SessionConfig>& audio_session_config() const {
-      return audio_receiver_config_;
-    }
-    Receiver* video_receiver() const { return video_receiver_; }
-    const absl::optional<SessionConfig>& video_session_config() const {
-      return video_receiver_config_;
-    }
-
-   private:
-    Receiver* audio_receiver_;
-    absl::optional<SessionConfig> audio_receiver_config_;
-    Receiver* video_receiver_;
-    absl::optional<SessionConfig> video_receiver_config_;
+    absl::optional<ConfiguredReceiver<AudioStream>> audio;
+    absl::optional<ConfiguredReceiver<VideoStream>> video;
   };
 
   // The embedder should provide a client for handling connections.
@@ -90,7 +77,6 @@ class ReceiverSession final : public MessagePort::Client {
 
   // Note: embedders are required to implement the following
   // codecs to be Cast V2 compliant: H264, VP8, AAC, Opus.
-  // TODO(jophba): add additional fields for preferences.
   struct Preferences {
     Preferences();
     Preferences(std::vector<VideoCodec> video_codecs,