Implement core audio methods for getting/setting volume settings

src/volume/coreAudio.go

@@ -0,0 +1,134 @@
+package volume
+
+/*
+ #cgo CFLAGS: -x objective-c
+ #cgo LDFLAGS: -framework CoreAudio
+ #include <CoreAudio/CoreAudio.h>
+*/
+import "C"
+import (
+	"unsafe"
+)
+
+type OSStatus C.OSStatus
+
+const (
+	AudioHardwareNoError = C.kAudioHardwareNoError
+)
+
+type AudioObjectID uint32
+
+func GetDefaultOutputDevice() (AudioObjectID, OSStatus) {
+	properties := C.AudioObjectPropertyAddress{
+		C.kAudioHardwarePropertyDefaultOutputDevice,
+		C.kAudioObjectPropertyScopeGlobal,
+		C.kAudioObjectPropertyElementMain,
+	}
+
+	var data C.AudioObjectID
+	dataSize := C.UInt32(unsafe.Sizeof(data))
+
+	result := C.AudioObjectGetPropertyData(
+		C.kAudioObjectSystemObject,
+		&properties,
+		C.UInt32(0),
+		unsafe.Pointer(nil),
+		&dataSize,
+		unsafe.Pointer(&data),
+	)
+
+	return AudioObjectID(data), OSStatus(result)
+}
+
+func GetVolume(objectID AudioObjectID) (float32, OSStatus) {
+
+	properties := C.AudioObjectPropertyAddress{
+		C.kAudioDevicePropertyVolumeScalar,
+		C.kAudioDevicePropertyScopeOutput,
+		0, //main channel
+	}
+
+	var data C.Float32
+	dataSize := C.UInt32(unsafe.Sizeof(data))
+
+	result := C.AudioObjectGetPropertyData(
+		C.AudioObjectID(objectID),
+		&properties,
+		C.UInt32(0),
+		unsafe.Pointer(nil),
+		&dataSize,
+		unsafe.Pointer(&data),
+	)
+
+	return float32(data), OSStatus(result)
+}
+
+func SetVolume(objectID AudioObjectID, volume float32) OSStatus {
+
+	properties := C.AudioObjectPropertyAddress{
+		C.kAudioDevicePropertyVolumeScalar,
+		C.kAudioDevicePropertyScopeOutput,
+		0, //main channel
+	}
+
+	data := C.Float32(volume)
+
+	result := C.AudioObjectSetPropertyData(
+		C.AudioObjectID(objectID),
+		&properties,
+		C.UInt32(0),
+		unsafe.Pointer(nil),
+		C.UInt32(unsafe.Sizeof(data)),
+		unsafe.Pointer(&data),
+	)
+
+	return OSStatus(result)
+}
+
+func GetMute(objectID AudioObjectID) (bool, OSStatus) {
+
+	properties := C.AudioObjectPropertyAddress{
+		C.kAudioDevicePropertyMute,
+		C.kAudioDevicePropertyScopeOutput,
+		0, //main channel
+	}
+
+	var data C.UInt32
+	dataSize := C.UInt32(unsafe.Sizeof(data))
+
+	result := C.AudioObjectGetPropertyData(
+		C.AudioObjectID(objectID),
+		&properties,
+		C.UInt32(0),
+		unsafe.Pointer(nil),
+		&dataSize,
+		unsafe.Pointer(&data),
+	)
+
+	dataAsBool := uint32(data) != 0
+	return dataAsBool, OSStatus(result)
+}
+
+func SetMute(objectID AudioObjectID, mute bool) OSStatus {
+
+	properties := C.AudioObjectPropertyAddress{
+		C.kAudioDevicePropertyMute,
+		C.kAudioDevicePropertyScopeOutput,
+		0, //main channel
+	}
+
+	data := C.UInt32(0)
+	if mute {
+		data = C.UInt32(1)
+	}
+
+	result := C.AudioObjectSetPropertyData(
+		C.AudioObjectID(objectID),
+		&properties,
+		C.UInt32(0),
+		unsafe.Pointer(nil),
+		C.UInt32(unsafe.Sizeof(data)),
+		unsafe.Pointer(&data),
+	)
+	return OSStatus(result)
+}