webrtcsink: add custom signaller example

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-rs/-/merge_requests/1340>

net/webrtc/Cargo.toml

@@ -93,3 +93,6 @@ name = "webrtcsink-stats-server"
 
 [[example]]
 name = "webrtcsink-high-quality-tune"
+
+[[example]]
+name = "webrtcsink-custom-signaller"

net/webrtc/examples/webrtcsink-custom-signaller/main.rs

@@ -0,0 +1,41 @@
+mod signaller;
+
+// from outside the plugin repository, one would need to add plugin package as follows:
+// [dependencies]
+// gstrswebrtc = { package = "gst-plugin-webrtc", git = "https://gitlab.freedesktop.org/gstreamer/gst-plugins-rs/" }
+extern crate gstrswebrtc;
+
+use anyhow::Error;
+use gst::prelude::*;
+use gstrswebrtc::signaller as signaller_interface;
+use gstrswebrtc::webrtcsink;
+
+fn main() -> Result<(), Error> {
+    gst::init()?;
+
+    let custom_signaller = signaller::MyCustomSignaller::new();
+    let webrtcsink = webrtcsink::BaseWebRTCSink::with_signaller(
+        signaller_interface::Signallable::from(custom_signaller),
+    );
+
+    let pipeline = gst::Pipeline::new();
+
+    let video_src = gst::ElementFactory::make("videotestsrc").build().unwrap();
+
+    pipeline
+        .add_many([&video_src, webrtcsink.upcast_ref()])
+        .unwrap();
+    video_src
+        .link(webrtcsink.upcast_ref::<gst::Element>())
+        .unwrap();
+
+    let bus = pipeline.bus().unwrap();
+
+    pipeline.set_state(gst::State::Playing).unwrap();
+
+    let _msg = bus.timed_pop_filtered(gst::ClockTime::NONE, &[gst::MessageType::Eos]);
+
+    pipeline.set_state(gst::State::Null).unwrap();
+
+    Ok(())
+}

net/webrtc/examples/webrtcsink-custom-signaller/signaller/imp.rs

@@ -0,0 +1,48 @@
+use gst::glib;
+use gst::subclass::prelude::*;
+use gst_webrtc::WebRTCSessionDescription;
+
+use gstrswebrtc::signaller::{Signallable, SignallableImpl};
+
+#[derive(Default)]
+pub struct Signaller {}
+
+impl Signaller {}
+
+impl SignallableImpl for Signaller {
+    fn start(&self) {
+        unimplemented!()
+    }
+
+    fn stop(&self) {
+        unimplemented!()
+    }
+
+    fn send_sdp(&self, _session_id: &str, _sdp: &WebRTCSessionDescription) {
+        unimplemented!()
+    }
+
+    fn add_ice(
+        &self,
+        _session_id: &str,
+        _candidate: &str,
+        _sdp_m_line_index: u32,
+        _sdp_mid: Option<String>,
+    ) {
+        unimplemented!()
+    }
+
+    fn end_session(&self, _session_id: &str) {
+        unimplemented!()
+    }
+}
+
+#[glib::object_subclass]
+impl ObjectSubclass for Signaller {
+    const NAME: &'static str = "MyCustomWebRTCSinkSignaller";
+    type Type = super::MyCustomSignaller;
+    type ParentType = glib::Object;
+    type Interfaces = (Signallable,);
+}
+
+impl ObjectImpl for Signaller {}

net/webrtc/examples/webrtcsink-custom-signaller/signaller/mod.rs

@@ -0,0 +1,23 @@
+use gst::glib;
+use gstrswebrtc::signaller::Signallable;
+
+mod imp;
+
+glib::wrapper! {
+    pub struct MyCustomSignaller(ObjectSubclass<imp::Signaller>) @implements Signallable;
+}
+
+unsafe impl Send for MyCustomSignaller {}
+unsafe impl Sync for MyCustomSignaller {}
+
+impl MyCustomSignaller {
+    pub fn new() -> Self {
+        glib::Object::new()
+    }
+}
+
+impl Default for MyCustomSignaller {
+    fn default() -> Self {
+        MyCustomSignaller::new()
+    }
+}