initial commit of device monitor

examples/device_monitor/main.go

@@ -0,0 +1,81 @@
+// 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 monitor")
+	// 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")
+
+	monitor := gst.NewDeviceMonitor()
+	fmt.Println("Created device monitor", monitor)
+
+	// if err != nil {
+	// 	fmt.Println("ERROR:", err)
+	// 	os.Exit(2)
+	// }
+	caps := gst.NewCapsFromString("video/x-raw")
+
+	monitor.AddFilter("Video/Source", caps)
+
+	fmt.Println("Getting device monitor bus")
+	bus := monitor.GetBus()
+	fmt.Println("Got device monitor bus", bus)
+
+	bus.AddWatch(func(msg *gst.Message) bool {
+		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)
+		}
+		return true
+	})
+
+	monitor.Start()
+	fmt.Println("Started device monitor")
+	devices := monitor.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_monitor.go

@@ -0,0 +1,77 @@
+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 DeviceMonitor struct {
+	ptr *C.GstDeviceMonitor
+	bus *Bus
+}
+
+func NewDeviceMonitor() *DeviceMonitor {
+	monitor := C.gst_device_monitor_new()
+	if monitor == nil {
+		return nil
+	}
+	return &DeviceMonitor{ptr: monitor}
+}
+
+func (d *DeviceMonitor) AddFilter(classes string, caps *Caps) {
+	var cClasses *C.gchar
+	if classes != "" {
+		cClasses = C.CString(classes)
+		defer C.free(unsafe.Pointer(cClasses))
+	}
+
+	C.gst_device_monitor_add_filter(d.ptr, cClasses, caps.Instance())
+	// if caps == nil {
+	// 	return nil
+	// }
+	//should return if we were able to add the filter
+}
+
+// GetPipelineBus returns the message bus for this pipeline.
+func (d *DeviceMonitor) GetBus() *Bus {
+	if d.bus == nil {
+		cBus := C.gst_device_monitor_get_bus(d.ptr)
+		d.bus = FromGstBusUnsafeFull(unsafe.Pointer(cBus))
+	}
+	return d.bus
+}
+
+func (d *DeviceMonitor) Start() bool {
+	return gobool(C.gst_device_monitor_start(d.ptr))
+	//should return if we were able to add the filter
+}
+
+func (d *DeviceMonitor) Stop() {
+	C.gst_device_monitor_stop(d.ptr)
+	//should return if we were able to add the filter
+}
+
+func (d *DeviceMonitor) GetDevices() []*Device {
+	glist := C.gst_device_monitor_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
+}
+
+//https://gstreamer.freedesktop.org/documentation/gstreamer/gstdevicemonitor.html?gi-language=c
+//gst_device_monitor_get_providers
+//gst_device_monitor_get_show_all_devices
+//gst_device_monitor_remove_filter
+//gst_device_monitor_set_show_all_devices