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, 83 insertions, 0 deletions

diff --git a/Framework/MASShortcutBinder.m b/Framework/MASShortcutBinder.m
new file mode 100644
index 0000000..d6249a8
--- /dev/null
+++ b/Framework/MASShortcutBinder.m
@@ -0,0 +1,83 @@
+#import "MASShortcutBinder.h"
+#import "MASShortcut.h"
+
+@interface MASShortcutBinder ()
+@property(strong) NSMutableDictionary *actions;
+@property(strong) NSMutableDictionary *shortcuts;
+@end
+
+@implementation MASShortcutBinder
+
+#pragma mark Initialization
+
+- (id) init
+{
+    self = [super init];
+    [self setActions:[NSMutableDictionary dictionary]];
+    [self setShortcuts:[NSMutableDictionary dictionary]];
+    return self;
+}
+
+- (void) dealloc
+{
+    for (NSString *bindingName in [_actions allKeys]) {
+        [self unbind:bindingName];
+    }
+}
+
+#pragma mark Bindings
+
+- (void) bindShortcutWithDefaultsKey: (NSString*) defaultsKeyName toAction: (dispatch_block_t) action
+{
+    [_actions setObject:[action copy] forKey:defaultsKeyName];
+    NSDictionary *bindingOptions = @{NSValueTransformerNameBindingOption: NSKeyedUnarchiveFromDataTransformerName};
+    [self bind:defaultsKeyName toObject:[NSUserDefaultsController sharedUserDefaultsController]
+        withKeyPath:[@"values." stringByAppendingString:defaultsKeyName] options:bindingOptions];
+}
+
+- (void) breakBindingWithDefaultsKey: (NSString*) defaultsKeyName
+{
+    [_shortcutMonitor unregisterShortcut:[_shortcuts objectForKey:defaultsKeyName]];
+    [_shortcuts removeObjectForKey:defaultsKeyName];
+    [_actions removeObjectForKey:defaultsKeyName];
+    [self unbind:defaultsKeyName];
+}
+
+- (BOOL) isRegisteredAction: (NSString*) name
+{
+    return !![_actions objectForKey:name];
+}
+
+- (id) valueForUndefinedKey: (NSString*) key
+{
+    return [self isRegisteredAction:key] ?
+        [_shortcuts objectForKey:key] :
+        [super valueForUndefinedKey:key];
+}
+
+- (void) setValue: (id) value forUndefinedKey: (NSString*) key
+{
+    if (![self isRegisteredAction:key]) {
+        [super setValue:value forUndefinedKey:key];
+        return;
+    }
+
+    MASShortcut *newShortcut = value;
+    MASShortcut *currentShortcut = [_shortcuts objectForKey:key];
+
+    // Unbind previous shortcut if any
+    if (currentShortcut != nil) {
+        [_shortcutMonitor unregisterShortcut:currentShortcut];
+    }
+
+    // Just deleting the old shortcut
+    if (newShortcut == nil) {
+        return;
+    }
+
+    // Bind new shortcut
+    [_shortcuts setObject:newShortcut forKey:key];
+    [_shortcutMonitor registerShortcut:newShortcut withAction:[_actions objectForKey:key]];
+}
+
+@end