add basic support for device provider

examples/device_provider/main.go

@@ -0,0 +1,56 @@
+// This example uses gstreamer's discoverer api.
+//
+// https://gstreamer.freedesktop.org/data/doc/gstreamer/head/gst-plugins-base-libs/html/GstDiscoverer.html
+// To detect as much information from a given URI.
+// The amount of time that the discoverer is allowed to use is limited by a timeout.
+// This allows to handle e.g. network problems gracefully. When the timeout hits before
+// discoverer was able to detect anything, discoverer will report an error.
+// In this example, we catch this error and stop the application.
+// Discovered information could for example contain the stream's duration or whether it is
+// seekable (filesystem) or not (some http servers).
+package main
+
+import (
+	"fmt"
+
+	"github.com/tinyzimmer/go-glib/glib"
+	"github.com/tinyzimmer/go-gst/examples"
+	"github.com/tinyzimmer/go-gst/gst"
+)
+
+func runPipeline(loop *glib.MainLoop) error {
+
+	gst.Init(nil)
+	fmt.Println("Running device provider")
+	// if len(os.Args) < 2 {
+	// 	fmt.Printf("USAGE: %s <uri>\n", os.Args[0])
+	// 	os.Exit(1)
+	// }
+
+	// uri := os.Args[1]
+	fmt.Println("Creating device monitor")
+
+	provider := gst.FindDeviceProviderByName("decklinkdeviceprovider")
+	fmt.Println("Created device provider", provider)
+
+	// if err != nil {
+	// 	fmt.Println("ERROR:", err)
+	// 	os.Exit(2)
+	// }
+
+	fmt.Println("listing devices from provider")
+	devices := provider.GetDevices()
+	for i, v := range devices {
+		fmt.Printf("Device: %d %s\n", i, v.GetDisplayName())
+	}
+
+	loop.Run()
+
+	return nil
+}
+
+func main() {
+	examples.RunLoop(func(loop *glib.MainLoop) error {
+		return runPipeline(loop)
+	})
+}

gst/gst_device_provider.go

@@ -0,0 +1,29 @@
+package gst
+
+// #include "gst.go.h"
+import "C"
+
+import (
+	"unsafe"
+
+	"github.com/tinyzimmer/go-glib/glib"
+)
+
+// DeviceMonitor is a Go representation of a GstDeviceMonitor.
+type DeviceProvider struct {
+	ptr *C.GstDeviceProvider
+}
+
+func (d *DeviceProvider) GetDevices() []*Device {
+	glist := C.gst_device_provider_get_devices(d.ptr)
+	if glist == nil {
+		return nil
+	}
+	goList := glib.WrapList(uintptr(unsafe.Pointer(glist)))
+	out := make([]*Device, 0)
+	goList.Foreach(func(item interface{}) {
+		pt := item.(unsafe.Pointer)
+		out = append(out, FromGstDeviceUnsafeFull(pt))
+	})
+	return out
+}

gst/gst_device_provider_factory.go

@@ -0,0 +1,23 @@
+package gst
+
+// #include "gst.go.h"
+import "C"
+
+import (
+	"unsafe"
+)
+
+// DeviceMonitor is a Go representation of a GstDeviceMonitor.
+type DeviceProviderFactory struct {
+	ptr *C.GstDeviceProviderFactory
+}
+
+func FindDeviceProviderByName(factoryName string) *DeviceProvider {
+	cFactoryName := C.CString(factoryName)
+	defer C.free(unsafe.Pointer(cFactoryName))
+	provider := C.gst_device_provider_factory_get_by_name((*C.gchar)(unsafe.Pointer(cFactoryName)))
+	if provider == nil {
+		return nil
+	}
+	return &DeviceProvider{ptr: provider}
+}