From 682a4b03d75f50abaf63da6834f33dc6df7dfbb0 Mon Sep 17 00:00:00 2001
From: RSWilli <bartel.wilhelm@gmail.com>
Date: Fri, 30 Aug 2024 11:23:40 +0200
Subject: [PATCH] change emit docs, add tests for signal emits

---
 gst/gst_element.go           | 12 +++--
 gst/gst_element_emit_test.go | 95 ++++++++++++++++++++++++++++++++++++
 2 files changed, 102 insertions(+), 5 deletions(-)
 create mode 100644 gst/gst_element_emit_test.go

diff --git a/gst/gst_element.go b/gst/gst_element.go
index bfc1014..1038f68 100644
--- a/gst/gst_element.go
+++ b/gst/gst_element.go
@@ -200,12 +200,14 @@ func (e *Element) ContinueState(ret StateChangeReturn) StateChangeReturn {
 	return StateChangeReturn(C.gst_element_continue_state(e.Instance(), C.GstStateChangeReturn(ret)))
 }
 
-// Emit is a wrapper around g_signal_emitv() and emits the signal specified by the string s to an Object. Arguments to
-// callback functions connected to this signal must be specified in args. Emit() returns an interface{} which must be
-// type asserted as the Go equivalent type to the return value for native C callback.
+// Emit is a wrapper around g_signal_emitv() and emits the signal
+// specified by the string s to an Object. This means that it performs identically to
+// g_signal_emit_by_name. Arguments to callback functions connected to this signal must
+// be specified in args. Emit() returns an interface{} which contains the go equivalent of the C return value.
 //
-// Note that this code is unsafe in that the types of values in args are not checked against whether they are suitable
-// for the callback.
+// Make sure that the Types are known to go-glib. Special types need to be registered with
+// RegisterGValueMarshalers before calling Emit. Sub libraries of go-gst (sdp, rtp, webrtc, base, etc.)
+// register their types when they are imported via init() functions.
 func (e *Element) Emit(signal string, args ...interface{}) (interface{}, error) {
 	// We are wrapping this for the same reason as Connect.
 	if e.TypeFromInstance() != glib.Type(C.GST_TYPE_ELEMENT) {
diff --git a/gst/gst_element_emit_test.go b/gst/gst_element_emit_test.go
new file mode 100644
index 0000000..a7f5693
--- /dev/null
+++ b/gst/gst_element_emit_test.go
@@ -0,0 +1,95 @@
+package gst_test
+
+import (
+	"errors"
+	"strings"
+	"testing"
+
+	"github.com/go-gst/go-glib/glib"
+	"github.com/go-gst/go-gst/gst"
+)
+
+func TestSignalEmitSimpleReturnValue(t *testing.T) {
+	gst.Init(nil)
+	webrtcbin, err := gst.NewElement("webrtcbin")
+
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	okI, err := webrtcbin.Emit("add-turn-server", "turn://user:password@host:1234")
+
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	ok := okI.(bool)
+
+	if !ok {
+		t.Fatal("Failed to add turn server")
+	}
+}
+
+func TestSignalEmitGObjectReturnValue(t *testing.T) {
+	gst.Init(nil)
+
+	elements := []string{
+		"rtpbin", "name=rtpbin",
+
+		"videotestsrc", "!", "videoconvert", "!", "queue", "!",
+		"x264enc", "bframes=0", "speed-preset=ultrafast", "tune=zerolatency", "name=encoder", "!", "queue", "!", "rtph264pay", "config-interval=1", "!", "rtpbin.send_rtp_sink_0", "rtpbin.send_rtp_src_0", "!",
+
+		"udpsink", "host=127.0.0.1", "port=5510", "sync=false", "async=false", "rtpbin.send_rtcp_src_0", "!",
+
+		"udpsink", "host=127.0.0.1", "port=5511", "sync=false", "async=false",
+
+		"udpsrc", "port=5511", "caps=\"application/x-rtcp\"", "!", "rtpbin.recv_rtcp_sink_0",
+	}
+
+	pipeline, err := gst.NewPipelineFromString(strings.Join(elements, " "))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	rtpbin, err := pipeline.GetElementByName("rtpbin")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	errchan := make(chan error)
+
+	rtpbin.Connect("on-new-ssrc", func(bin *gst.Element, sessionID uint, ssrc uint32) {
+		retI, err := rtpbin.Emit("get-internal-session", sessionID)
+
+		if err != nil {
+			errchan <- err
+		}
+
+		rtpSession, ok := retI.(*glib.Object)
+
+		if !ok {
+			errchan <- errors.New("could not cast return value to *glib.Object")
+		}
+
+		bw, err := rtpSession.GetProperty("bandwidth")
+
+		if err != nil {
+			errchan <- err
+		}
+
+		_ = bw
+
+		close(errchan)
+	})
+
+	pipeline.SetState(gst.StatePlaying)
+
+	err = <-errchan
+
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	pipeline.SetState(gst.StateNull)
+
+}