Support for an action on shortcut key up

Demo/AppDelegate.m

@@ -57,6 +57,15 @@ - (void)playShortcutFeedback
     });
 }
 
+- (void)playShortcutUpFeedback
+{
+    [[NSSound soundNamed:@"Tink"] play];
+    [_feedbackTextField setStringValue:NSLocalizedString(@"Shortcut unpressed!", @"Feedback that’s displayed when user presses the sample shortcut.")];
+    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.5 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
+        [_feedbackTextField setStringValue:@""];
+    });
+}
+
 // Handle changes in user defaults. We have to check keyPath here to see which of the
 // two checkboxes was changed. This is not very elegant, in practice you could use something
 // like https://github.com/facebook/KVOController with a nicer API.
@@ -80,6 +89,8 @@ - (void) setCustomShortcutEnabled: (BOOL) enabled
     if (enabled) {
         [[MASShortcutBinder sharedBinder] bindShortcutWithDefaultsKey:MASCustomShortcutKey toAction:^{
             [self playShortcutFeedback];
+        } onKeyUp:^{
+            [self playShortcutUpFeedback];
         }];
     } else {
         [[MASShortcutBinder sharedBinder] breakBindingWithDefaultsKey:MASCustomShortcutKey];

Framework/MASHotKey.h

@@ -6,6 +6,7 @@ extern FourCharCode const MASHotKeySignature;
 
 @property(readonly) UInt32 carbonID;
 @property(copy) dispatch_block_t action;
+@property(copy) dispatch_block_t actionUp;
 
 + (instancetype) registeredHotKeyWithShortcut: (MASShortcut*) shortcut;
 

Framework/MASShortcutBinder.h

@@ -47,6 +47,14 @@
 */
 - (void) bindShortcutWithDefaultsKey: (NSString*) defaultsKeyName toAction: (dispatch_block_t) action;
 
+/**
+ Binds given actions to a shortcut stored under the given defaults key.
+
+ In other words, no matter what shortcut you store under the given key,
+ pressing it will always trigger the given action.
+ */
+- (void) bindShortcutWithDefaultsKey: (NSString*) defaultsKeyName toAction: (dispatch_block_t) action onKeyUp: (dispatch_block_t) actionUp;
+
 /**
  Disconnect the binding between user defaults and action.
 

Framework/MASShortcutBinder.m

@@ -3,6 +3,7 @@
 
 @interface MASShortcutBinder ()
 @property(strong) NSMutableDictionary *actions;
+@property(strong) NSMutableDictionary *actionsUp;
 @property(strong) NSMutableDictionary *shortcuts;
 @end
 
@@ -14,6 +15,7 @@ - (id) init
 {
     self = [super init];
     [self setActions:[NSMutableDictionary dictionary]];
+    [self setActionsUp:[NSMutableDictionary dictionaryWithCapacity:0]];
     [self setShortcuts:[NSMutableDictionary dictionary]];
     [self setShortcutMonitor:[MASShortcutMonitor sharedMonitor]];
     [self setBindingOptions:@{NSValueTransformerNameBindingOption: NSKeyedUnarchiveFromDataTransformerName}];
@@ -40,12 +42,21 @@ + (instancetype) sharedBinder
 #pragma mark Registration
 
 - (void) bindShortcutWithDefaultsKey: (NSString*) defaultsKeyName toAction: (dispatch_block_t) action
+{
+    [self bindShortcutWithDefaultsKey:defaultsKeyName toAction:action onKeyUp:nil];
+}
+
+- (void) bindShortcutWithDefaultsKey: (NSString*) defaultsKeyName toAction: (dispatch_block_t) action onKeyUp: (dispatch_block_t) actionUp
 {
     NSAssert([defaultsKeyName rangeOfString:@"."].location == NSNotFound,
         @"Illegal character in binding name (“.”), please see http://git.io/x5YS.");
     NSAssert([defaultsKeyName rangeOfString:@" "].location == NSNotFound,
         @"Illegal character in binding name (“ ”), please see http://git.io/x5YS.");
     [_actions setObject:[action copy] forKey:defaultsKeyName];
+    if (actionUp)
+        [_actionsUp setObject:[actionUp copy] forKey:defaultsKeyName];
+    else
+        [_actionsUp removeObjectForKey:defaultsKeyName];
     [self bind:defaultsKeyName
         toObject:[NSUserDefaultsController sharedUserDefaultsController]
         withKeyPath:[@"values." stringByAppendingString:defaultsKeyName]
@@ -57,6 +68,7 @@ - (void) breakBindingWithDefaultsKey: (NSString*) defaultsKeyName
     [_shortcutMonitor unregisterShortcut:[_shortcuts objectForKey:defaultsKeyName]];
     [_shortcuts removeObjectForKey:defaultsKeyName];
     [_actions removeObjectForKey:defaultsKeyName];
+    [_actionsUp removeObjectForKey:defaultsKeyName];
     [self unbind:defaultsKeyName];
 }
 
@@ -115,7 +127,7 @@ - (void) setValue: (id) value forUndefinedKey: (NSString*) key
 
     // Bind new shortcut
     [_shortcuts setObject:newShortcut forKey:key];
-    [_shortcutMonitor registerShortcut:newShortcut withAction:[_actions objectForKey:key]];
+    [_shortcutMonitor registerShortcut:newShortcut withAction:[_actions objectForKey:key] onKeyUp:[_actionsUp objectForKey:key]];
 }
 
 @end

Framework/MASShortcutMonitor.h

@@ -19,6 +19,13 @@
  It may burn your house or cut your fingers. You have been warned.
 */
 - (BOOL) registerShortcut: (MASShortcut*) shortcut withAction: (dispatch_block_t) action;
+/**
+ Register a shortcut along with an actions.
+
+ Attempting to insert an already registered shortcut probably won’t work.
+ It may burn your house or cut your fingers. You have been warned.
+ */
+- (BOOL) registerShortcut: (MASShortcut*) shortcut withAction: (dispatch_block_t) action onKeyUp: (dispatch_block_t) actionUp;
 - (BOOL) isShortcutRegistered: (MASShortcut*) shortcut;
 
 - (void) unregisterShortcut: (MASShortcut*) shortcut;

Framework/MASShortcutMonitor.m

@@ -16,9 +16,14 @@ - (instancetype) init
 {
     self = [super init];
     [self setHotKeys:[NSMutableDictionary dictionary]];
-    EventTypeSpec hotKeyPressedSpec = { .eventClass = kEventClassKeyboard, .eventKind = kEventHotKeyPressed };
+    EventTypeSpec eventTypeSpecs[2] = {
+        { .eventClass = kEventClassKeyboard, .eventKind = kEventHotKeyPressed },
+        { .eventClass = kEventClassKeyboard, .eventKind = kEventHotKeyReleased }
+    };
+
     OSStatus status = InstallEventHandler(GetEventDispatcherTarget(), MASCarbonEventCallback,
-        1, &hotKeyPressedSpec, (__bridge void*)self, &_eventHandlerRef);
+                                          2, eventTypeSpecs,
+                                          (__bridge void*)self, &_eventHandlerRef);
     if (status != noErr) {
         return nil;
     }
@@ -46,10 +51,16 @@ + (instancetype) sharedMonitor
 #pragma mark Registration
 
 - (BOOL) registerShortcut: (MASShortcut*) shortcut withAction: (dispatch_block_t) action
+{
+    return [self registerShortcut:shortcut withAction:action onKeyUp:nil];
+}
+
+- (BOOL) registerShortcut: (MASShortcut*) shortcut withAction: (dispatch_block_t) action onKeyUp: (dispatch_block_t) actionUp
 {
     MASHotKey *hotKey = [MASHotKey registeredHotKeyWithShortcut:shortcut];
     if (hotKey) {
         [hotKey setAction:action];
+        [hotKey setActionUp:actionUp];
         [_hotKeys setObject:hotKey forKey:shortcut];
         return YES;
     } else {
@@ -91,7 +102,9 @@ - (void) handleEvent: (EventRef) event
     [_hotKeys enumerateKeysAndObjectsUsingBlock:^(MASShortcut *shortcut, MASHotKey *hotKey, BOOL *stop) {
         if (hotKeyID.id == [hotKey carbonID]) {
             if ([hotKey action]) {
-                dispatch_async(dispatch_get_main_queue(), [hotKey action]);
+                dispatch_block_t action = (GetEventKind(event) == kEventHotKeyReleased) ? [hotKey actionUp] : [hotKey action];
+                if (action)
+                    dispatch_async(dispatch_get_main_queue(), action);
             }
             *stop = YES;
         }