macosx: automagically update the audio device list when the OS tells us to (close #8282)

modules/gui/macosx/MainMenu.m

@@ -24,6 +24,7 @@
 #import "MainMenu.h"
 #import <vlc_common.h>
 #import <vlc_playlist.h>
+#import <CoreAudio/CoreAudio.h>
 
 #import "intf.h"
 #import "open.h"
@@ -45,6 +46,19 @@
 #import "ExtensionsManager.h"
 #import "ConvertAndSave.h"
 
+static OSStatus HardwareListener        (AudioObjectID, UInt32, const AudioObjectPropertyAddress *, void *);
+
+static OSStatus HardwareListener(AudioObjectID inObjectID,  UInt32 inNumberAddresses, const AudioObjectPropertyAddress inAddresses[], void*inClientData)
+{
+    VLC_UNUSED(inObjectID);
+    VLC_UNUSED(inNumberAddresses);
+    VLC_UNUSED(inAddresses);
+    // give the core some time update its internal structure for the new device setup
+    [[VLCMainMenu sharedInstance] performSelector:@selector(refreshAudioDeviceList) withObject:nil afterDelay:.5];
+
+    return noErr;
+}
+
 @implementation VLCMainMenu
 static VLCMainMenu *_o_sharedInstance = nil;
 
@@ -86,6 +100,11 @@ static VLCMainMenu *_o_sharedInstance = nil;
 
 - (void)dealloc
 {
+    AudioObjectPropertyAddress audioDevicesAddress = { kAudioHardwarePropertyDevices, kAudioObjectPropertyScopeGlobal, kAudioObjectPropertyElementMaster };
+    OSStatus err = AudioObjectRemovePropertyListener(kAudioObjectSystemObject, &audioDevicesAddress, HardwareListener, nil);
+    if (err != noErr)
+        msg_Err(p_intf, "failed to add audio hardware listener (%i)", err);
+
     [[NSNotificationCenter defaultCenter] removeObserver: self];
 
     if (b_nib_about_loaded)
@@ -263,6 +282,13 @@ static VLCMainMenu *_o_sharedInstance = nil;
     [self setupExtensionsMenu];
 
     [self refreshAudioDeviceList];
+
+    AudioObjectPropertyAddress audioDevicesAddress = { kAudioHardwarePropertyDevices,
+                                                       kAudioObjectPropertyScopeGlobal,
+                                                       kAudioObjectPropertyElementMaster };
+    OSStatus err = AudioObjectAddPropertyListener(kAudioObjectSystemObject, &audioDevicesAddress, HardwareListener, nil);
+    if (err != noErr)
+        msg_Err(p_intf, "failed to add audio hardware listener (%i)", err);
 }
 
 - (void)initStrings