more work on the examples and regenerate using the gotk4 updates

examples/device_provider/main.go

@@ -0,0 +1,64 @@
+// This example uses gstreamer's device provider api.
+//
+// https://gstreamer.freedesktop.org/documentation/gstreamer/gstdeviceprovider.html
+package main
+
+import (
+	"context"
+	"fmt"
+	"os"
+
+	"github.com/go-gst/go-gst/pkg/gst"
+)
+
+func runPipeline() error {
+
+	gst.Init()
+	fmt.Println("Running device provider")
+
+	fmt.Println("Creating device monitor")
+
+	provider := gst.DeviceProviderFactoryGetByName("avfdeviceprovider")
+	fmt.Println("Created device provider")
+
+	if provider == nil {
+		fmt.Println("No provider found")
+		os.Exit(2)
+	}
+
+	fmt.Println("Starting device monitor")
+	provider.Start()
+	fmt.Println("Started device monitor")
+
+	fmt.Println("listing devices from provider")
+	devices := provider.GetDevices()
+	for i, v := range devices {
+		fmt.Printf("Device: %d %s\n", i, v.GetDisplayName())
+	}
+
+	fmt.Println("Getting device provider bus")
+	bus := provider.GetBus()
+	fmt.Println("Got device provider bus")
+
+	for msg := range bus.Messages(context.Background()) {
+		switch msg.Type() {
+		case gst.MessageDeviceAdded:
+			message := msg.ParseDeviceAdded().GetDisplayName()
+			fmt.Println("Added: ", message)
+		case gst.MessageDeviceRemoved:
+			message := msg.ParseDeviceRemoved().GetDisplayName()
+			fmt.Println("Removed: ", message)
+		default:
+			// All messages implement a Stringer. However, this is
+			// typically an expensive thing to do and should be avoided.
+			fmt.Println("Type: ", msg.Type())
+			fmt.Println("Message: ", msg.String())
+		}
+	}
+
+	return nil
+}
+
+func main() {
+	runPipeline()
+}