Refactored the shortcut dispatcher and bindings to user defaults.

This is a big change that was hard to split into smaller commits. There’s now
a new class to bind shortcuts to actions, a new class to bind user defaults’
keys to actions, and a new way to associate user defaults with the recorder
control (MASShortcutView). I have also updated the demo app to go with the
changes.

The new class to associate shortcuts with actions is called MASShortcutMonitor.
It wraps the Carbon hotkey magic and offers a simple interface to add a
shortcut along with a block that should be run when the shortcut is pressed.
It’s the lowest-level interface.

Since the usual requirement is to store the shortcuts into user defaults,
there’s also a higher-level interface offered by the MASShortcutBinder class.
That takes a defaults key and associates it with a block. When the shortcut
stored under the defaults key changes, the binder automatically switches to the
new shortcut. The class is a wrapper built atop of the previous one, the
MASShortcutMonitor – it simply adds, updates and removes shortcuts as the
user defaults change.

I have removed the special user defaults integration code from the recorder
control (MASShortcutView) and replaced it with a small Cocoa Bindings shim.
This means that in order to keep the recorder control in sync with the defaults
you just have to call the usual bind:toObject:withKeyPath:options: method,
like this:

[_shortcutView bind:MASShortcutBinding
    toObject:[NSUserDefaultsController sharedUserDefaultsController]
    withKeyPath[@"values.ExampleDefaultsKey"
    options:@{NSValueTransformerNameBindingOption:NSKeyedUnarchiveFromDataTransformerName}];

That’s more verbose than the previous solution, but it’s much cleaner and can
be swept under a convenience call if needed. I might also add a dictionaryValue
property later that would make it possible to bind the value to user defaults
directly, without a transformer, and would enable backward compatibility with
Shortcut Recorder.

1 files changed, 84 insertions, 0 deletions

diff --git a/Framework/MASShortcutMonitor.m b/Framework/MASShortcutMonitor.m
new file mode 100644
index 0000000..f1c7e9c
--- /dev/null
+++ b/Framework/MASShortcutMonitor.m
@@ -0,0 +1,84 @@
+#import "MASShortcutMonitor.h"
+#import "MASHotKey.h"
+
+@interface MASShortcutMonitor ()
+@property(assign) EventHandlerRef eventHandlerRef;
+@property(strong) NSMutableDictionary *hotKeys;
+@end
+
+static OSStatus MASCarbonEventCallback(EventHandlerCallRef, EventRef, void*);
+
+@implementation MASShortcutMonitor
+
+- (instancetype) init
+{
+    self = [super init];
+    [self setHotKeys:[NSMutableDictionary dictionary]];
+    EventTypeSpec hotKeyPressedSpec = { .eventClass = kEventClassKeyboard, .eventKind = kEventHotKeyPressed };
+    OSStatus status = InstallEventHandler(GetEventDispatcherTarget(), MASCarbonEventCallback,
+        1, &hotKeyPressedSpec, (__bridge void*)self, &_eventHandlerRef);
+    if (status != noErr) {
+        return nil;
+    }
+    return self;
+}
+
+- (void) dealloc
+{
+    if (_eventHandlerRef) {
+        RemoveEventHandler(_eventHandlerRef);
+        _eventHandlerRef = NULL;
+    }
+}
+
+#pragma mark Registration
+
+- (void) registerShortcut: (MASShortcut*) shortcut withAction: (dispatch_block_t) action
+{
+    MASHotKey *hotKey = [MASHotKey registeredHotKeyWithShortcut:shortcut];
+    [hotKey setAction:action];
+    [_hotKeys setObject:hotKey forKey:shortcut];
+}
+
+- (void) unregisterShortcut: (MASShortcut*) shortcut
+{
+    [_hotKeys removeObjectForKey:shortcut];
+}
+
+- (BOOL) isShortcutRegistered: (MASShortcut*) shortcut
+{
+    return !![_hotKeys objectForKey:shortcut];
+}
+
+#pragma mark Event Handling
+
+- (void) handleEvent: (EventRef) event
+{
+	if (GetEventClass(event) != kEventClassKeyboard) {
+        return;
+    }
+
+	EventHotKeyID hotKeyID;
+	OSStatus status = GetEventParameter(event, kEventParamDirectObject, typeEventHotKeyID, NULL, sizeof(hotKeyID), NULL, &hotKeyID);
+	if (status != noErr || hotKeyID.signature != MASHotKeySignature) {
+        return;
+    }
+
+    [_hotKeys enumerateKeysAndObjectsUsingBlock:^(MASShortcut *shortcut, MASHotKey *hotKey, BOOL *stop) {
+        if (hotKeyID.id == [hotKey carbonID]) {
+            if ([hotKey action]) {
+                dispatch_async(dispatch_get_main_queue(), [hotKey action]);
+            }
+            *stop = YES;
+        }
+    }];
+}
+
+@end
+
+static OSStatus MASCarbonEventCallback(EventHandlerCallRef _, EventRef event, void *context)
+{
+    MASShortcutMonitor *dispatcher = (__bridge id)context;
+    [dispatcher handleEvent:event];
+    return noErr;
+}