macosx: allow simultanous video or SPU track selection

Press the alt key to select more than 1 key.

This also fixes the state display in main menu when the selection changes.

modules/gui/macosx/menus/VLCMainMenu.m

@@ -186,6 +186,10 @@ typedef NS_ENUM(NSInteger, VLCObjectType) {
                            selector:@selector(updateTrackHandlingMenus:)
                                name:VLCPlayerTrackListChanged
                              object:nil];
+    [notificationCenter addObserver:self
+                           selector:@selector(updateTrackHandlingMenus:)
+                               name:VLCPlayerTrackSelectionChanged
+                             object:nil];
     [notificationCenter addObserver:self
                            selector:@selector(updateTitleAndChapterMenus:)
                                name:VLCPlayerTitleListChanged
@@ -906,6 +910,7 @@ typedef NS_ENUM(NSInteger, VLCObjectType) {
                  category:(enum es_format_category_e)category
 {
     [menu removeAllItems];
+    BOOL itemSelected = NO;
 
     NSMenuItem *menuItem = [[NSMenuItem alloc] initWithTitle:_NS("Disable")
                                                       action:@selector(unselectTrackCategory:)
@@ -923,14 +928,25 @@ typedef NS_ENUM(NSInteger, VLCObjectType) {
         [menuItem setTarget:self];
         [menuItem setRepresentedObject:metaDataItem];
         [menuItem setEnabled:YES];
-        [menuItem setState:metaDataItem.selected ? NSOnState : NSOffState];
+        if (metaDataItem.selected) {
+            itemSelected = YES;
+            [menuItem setState:NSOnState];
+        } else {
+            [menuItem setState:NSOffState];
+        }
         [menu addItem:menuItem];
     }
+
+    /* select the "Disabled" item in case no track is selected */
+    if (!itemSelected) {
+        [menu.itemArray.firstObject setState:NSOnState];
+    }
 }
 
 - (void)selectTrack:(NSMenuItem *)sender
 {
-    [_playerController selectTrack:[sender representedObject]];
+    NSEvent *currentEvent = [NSApp currentEvent];
+    [_playerController selectTrack:[sender representedObject] exclusively:!(currentEvent.modifierFlags & NSAlternateKeyMask)];
 }
 
 - (void)unselectTrackCategory:(NSMenuItem *)sender

modules/gui/macosx/playlist/VLCPlayerController.h

@@ -716,10 +716,12 @@ extern const CGFloat VLCVolumeDefault;
 
 /**
  * select a track
+ * @param the track to select
+ * @param indicate whether multiple tracks may be played (video and SPU only)
  * @note since tracks are unique, you do not need to specify the type
  * @note listen to VLCTrackSelectionChanged to be notified once the change occured
  */
-- (void)selectTrack:(VLCTrackMetaData *)track;
+- (void)selectTrack:(VLCTrackMetaData *)track exclusively:(BOOL)exclusiveSelection;
 
 /**
  * unselect a track

modules/gui/macosx/playlist/VLCPlayerController.m

@@ -1387,10 +1387,11 @@ static const struct vlc_player_aout_cbs player_aout_callbacks = {
     [_defaultNotificationCenter postNotificationName:VLCPlayerTrackListChanged object:nil];
 }
 
-- (void)selectTrack:(VLCTrackMetaData *)track
+- (void)selectTrack:(VLCTrackMetaData *)track exclusively:(BOOL)exclusiveSelection
 {
     vlc_player_Lock(_p_player);
-    vlc_player_SelectEsId(_p_player, track.esID, VLC_PLAYER_SELECT_EXCLUSIVE);
+    const enum es_format_category_e formatCategory = vlc_es_id_GetCat(track.esID);
+    vlc_player_SelectEsId(_p_player, track.esID, (formatCategory == AUDIO_ES || exclusiveSelection) ? VLC_PLAYER_SELECT_EXCLUSIVE : VLC_PLAYER_SELECT_SIMULTANEOUS);
     vlc_player_Unlock(_p_player);
 }
 
@@ -1767,7 +1768,7 @@ static const struct vlc_player_aout_cbs player_aout_callbacks = {
 
 - (NSString *)description
 {
-    return [NSString stringWithFormat:@"%@: name: %@", [VLCTrackMetaData className], self.name];
+    return [NSString stringWithFormat:@"%@: name: %@, selected: %i", [VLCTrackMetaData className], self.name, self.selected];
 }
 
 @end