net/webrtc: Extract BaseWebRTCSrc

Define a Base for all the webrtcsrc type elements
so they can all be derived from it. Similar to base
element defined for webrtcsink type elements

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-rs/-/merge_requests/1284>

2 files changed, 104 insertions, 60 deletions

diff --git a/net/webrtc/src/webrtcsrc/imp.rs b/net/webrtc/src/webrtcsrc/imp.rs
index 8b27cecf6..42a05108c 100644
--- a/net/webrtc/src/webrtcsrc/imp.rs
+++ b/net/webrtc/src/webrtcsrc/imp.rs
@@ -43,7 +43,7 @@ struct Settings {
 }
 
 #[derive(Default)]
-pub struct WebRTCSrc {
+pub struct BaseWebRTCSrc {
     settings: Mutex<Settings>,
     n_video_pads: AtomicU16,
     n_audio_pads: AtomicU16,
@@ -51,14 +51,21 @@ pub struct WebRTCSrc {
 }
 
 #[glib::object_subclass]
-impl ObjectSubclass for WebRTCSrc {
-    const NAME: &'static str = "GstWebRTCSrc";
-    type Type = super::WebRTCSrc;
+impl ObjectSubclass for BaseWebRTCSrc {
+    const NAME: &'static str = "GstBaseWebRTCSrc";
+    type Type = super::BaseWebRTCSrc;
     type ParentType = gst::Bin;
-    type Interfaces = (gst::URIHandler, gst::ChildProxy);
+    type Interfaces = (gst::ChildProxy,);
 }
 
-impl ObjectImpl for WebRTCSrc {
+unsafe impl<T: BaseWebRTCSrcImpl> IsSubclassable<T> for super::BaseWebRTCSrc {
+    fn class_init(class: &mut glib::Class<Self>) {
+        Self::parent_class_init::<T>(class);
+    }
+}
+pub(crate) trait BaseWebRTCSrcImpl: BinImpl {}
+
+impl ObjectImpl for BaseWebRTCSrc {
     fn properties() -> &'static [glib::ParamSpec] {
         static PROPS: Lazy<Vec<glib::ParamSpec>> = Lazy::new(|| {
             vec![
@@ -205,7 +212,7 @@ impl ObjectImpl for WebRTCSrc {
         static SIGNALS: Lazy<Vec<glib::subclass::Signal>> = Lazy::new(|| {
             vec![
                 /**
-                 * WebRTCSrc::request-encoded-filter:
+                 * BaseWebRTCSrc::request-encoded-filter:
                  * @producer_id: Identifier of the producer
                  * @pad_name: The name of the output pad
                  * @allowed_caps: the allowed caps for the output pad
@@ -278,7 +285,7 @@ struct SignallerSignals {
     handle_ice: glib::SignalHandlerId,
 }
 
-impl WebRTCSrc {
+impl BaseWebRTCSrc {
     fn webrtcbin(&self) -> gst::Bin {
         let state = self.state.lock().unwrap();
         let webrtcbin = state
@@ -562,15 +569,22 @@ impl WebRTCSrc {
         let mline = transceiver.map_or(mline, |t| Some(t.mlineindex()));
 
         // Same logic as gst_pad_create_stream_id and friends, making a hash of
-        // the URI and adding `:<some-id>`, here the ID is the mline of the
+        // the URI (session id, if URI doesn't exist) and adding `:<some-id>`, here the ID is the mline of the
         // stream in the SDP.
         mline.map(|mline| {
             let mut cs = glib::Checksum::new(glib::ChecksumType::Sha256).unwrap();
-            cs.update(
-                self.uri()
-                    .expect("get_stream_id should never be called if no URI has been set")
-                    .as_bytes(),
-            );
+
+            let data: String = if self
+                .signaller()
+                .has_property("uri", Some(String::static_type()))
+            {
+                self.signaller().property::<Option<String>>("uri").unwrap()
+            } else {
+                // use the session id
+                self.state.lock().unwrap().session_id.clone().unwrap()
+            };
+
+            cs.update(data.as_bytes());
 
             format!("{}:{mline}", cs.string().unwrap())
         })
@@ -983,20 +997,7 @@ impl WebRTCSrc {
     }
 }
 
-impl ElementImpl for WebRTCSrc {
-    fn metadata() -> Option<&'static gst::subclass::ElementMetadata> {
-        static ELEMENT_METADATA: Lazy<gst::subclass::ElementMetadata> = Lazy::new(|| {
-            gst::subclass::ElementMetadata::new(
-                "WebRTCSrc",
-                "Source/Network/WebRTC",
-                "WebRTC src",
-                "Thibault Saunier <tsaunier@igalia.com>",
-            )
-        });
-
-        Some(&*ELEMENT_METADATA)
-    }
-
+impl ElementImpl for BaseWebRTCSrc {
     fn pad_templates() -> &'static [gst::PadTemplate] {
         static PAD_TEMPLATES: Lazy<Vec<gst::PadTemplate>> = Lazy::new(|| {
             let mut video_caps_builder = gst::Caps::builder_full()
@@ -1095,11 +1096,11 @@ impl ElementImpl for WebRTCSrc {
     }
 }
 
-impl GstObjectImpl for WebRTCSrc {}
+impl GstObjectImpl for BaseWebRTCSrc {}
 
-impl BinImpl for WebRTCSrc {}
+impl BinImpl for BaseWebRTCSrc {}
 
-impl ChildProxyImpl for WebRTCSrc {
+impl ChildProxyImpl for BaseWebRTCSrc {
     fn child_by_index(&self, index: u32) -> Option<glib::Object> {
         if index == 0 {
             Some(self.signaller().upcast())
@@ -1123,6 +1124,60 @@ impl ChildProxyImpl for WebRTCSrc {
     }
 }
 
+#[derive(PartialEq)]
+enum SignallerState {
+    Started,
+    Stopped,
+}
+
+struct State {
+    session_id: Option<String>,
+    signaller_state: SignallerState,
+    webrtcbin: Option<gst::Element>,
+    flow_combiner: gst_base::UniqueFlowCombiner,
+    signaller_signals: Option<SignallerSignals>,
+    data_channel: Option<WebRTCDataChannel>,
+}
+
+impl Default for State {
+    fn default() -> Self {
+        Self {
+            signaller_state: SignallerState::Stopped,
+            session_id: None,
+            webrtcbin: None,
+            flow_combiner: Default::default(),
+            signaller_signals: Default::default(),
+            data_channel: None,
+        }
+    }
+}
+
+#[derive(Default)]
+pub struct WebRTCSrc {}
+
+impl ObjectImpl for WebRTCSrc {}
+
+impl GstObjectImpl for WebRTCSrc {}
+
+impl BinImpl for WebRTCSrc {}
+
+impl ElementImpl for WebRTCSrc {
+    fn metadata() -> Option<&'static gst::subclass::ElementMetadata> {
+        static ELEMENT_METADATA: Lazy<gst::subclass::ElementMetadata> = Lazy::new(|| {
+            gst::subclass::ElementMetadata::new(
+                "WebRTCSrc",
+                "Source/Network/WebRTC",
+                "WebRTC src",
+                "Thibault Saunier <tsaunier@igalia.com>",
+            )
+        });
+
+        Some(&*ELEMENT_METADATA)
+    }
+}
+
+impl BaseWebRTCSrcImpl for WebRTCSrc {}
+
 impl URIHandlerImpl for WebRTCSrc {
     const URI_TYPE: gst::URIType = gst::URIType::Src;
 
@@ -1131,7 +1186,9 @@ impl URIHandlerImpl for WebRTCSrc {
     }
 
     fn uri(&self) -> Option<String> {
-        self.signaller().property::<Option<String>>("uri")
+        let obj = self.obj();
+        let base = obj.upcast_ref::<super::BaseWebRTCSrc>().imp();
+        base.signaller().property::<Option<String>>("uri")
     }
 
     fn set_uri(&self, uri: &str) -> Result<(), glib::Error> {
@@ -1153,36 +1210,18 @@ impl URIHandlerImpl for WebRTCSrc {
         // See https://github.com/servo/rust-url/pull/768 for a PR implementing that
         url_str.replace_range(0..uri.scheme().len(), socket_scheme);
 
-        self.signaller().set_property("uri", &url_str);
+        let obj = self.obj();
+        let base = obj.upcast_ref::<super::BaseWebRTCSrc>().imp();
+        base.signaller().set_property("uri", &url_str);
 
         Ok(())
     }
 }
 
-#[derive(PartialEq)]
-enum SignallerState {
-    Started,
-    Stopped,
-}
-
-struct State {
-    session_id: Option<String>,
-    signaller_state: SignallerState,
-    webrtcbin: Option<gst::Element>,
-    flow_combiner: gst_base::UniqueFlowCombiner,
-    signaller_signals: Option<SignallerSignals>,
-    data_channel: Option<WebRTCDataChannel>,
-}
-
-impl Default for State {
-    fn default() -> Self {
-        Self {
-            signaller_state: SignallerState::Stopped,
-            session_id: None,
-            webrtcbin: None,
-            flow_combiner: Default::default(),
-            signaller_signals: Default::default(),
-            data_channel: None,
-        }
-    }
+#[glib::object_subclass]
+impl ObjectSubclass for WebRTCSrc {
+    const NAME: &'static str = "GstWebRTCSrc";
+    type Type = super::WebRTCSrc;
+    type ParentType = super::BaseWebRTCSrc;
+    type Interfaces = (gst::URIHandler,);
 }
diff --git a/net/webrtc/src/webrtcsrc/mod.rs b/net/webrtc/src/webrtcsrc/mod.rs
index 72167d5d1..b85612bcc 100644
--- a/net/webrtc/src/webrtcsrc/mod.rs
+++ b/net/webrtc/src/webrtcsrc/mod.rs
@@ -42,7 +42,11 @@ use gst::prelude::*;
 use gst::{glib, prelude::StaticType};
 
 glib::wrapper! {
-    pub struct WebRTCSrc(ObjectSubclass<imp::WebRTCSrc>) @extends gst::Bin, gst::Element, gst::Object, @implements gst::URIHandler, gst::ChildProxy;
+    pub struct BaseWebRTCSrc(ObjectSubclass<imp::BaseWebRTCSrc>) @extends gst::Bin, gst::Element, gst::Object, @implements gst::ChildProxy;
+}
+
+glib::wrapper! {
+    pub struct WebRTCSrc(ObjectSubclass<imp::WebRTCSrc>) @extends BaseWebRTCSrc, gst::Bin, gst::Element, gst::Object, @implements gst::URIHandler, gst::ChildProxy;
 }
 
 glib::wrapper! {
@@ -50,6 +54,7 @@ glib::wrapper! {
 }
 
 pub fn register(plugin: Option<&gst::Plugin>) -> Result<(), glib::BoolError> {
+    BaseWebRTCSrc::static_type().mark_as_plugin_api(gst::PluginAPIFlags::empty());
     WebRTCSignallerRole::static_type().mark_as_plugin_api(gst::PluginAPIFlags::empty());
     WebRTCSrcPad::static_type().mark_as_plugin_api(gst::PluginAPIFlags::empty());
     Signallable::static_type().mark_as_plugin_api(gst::PluginAPIFlags::empty());