keychain/ckks/CKKSListenerCollection.m

   1
   2 #if OCTAGON
   3
   4 #import "keychain/ckks/CKKSListenerCollection.h"
   5 #import "keychain/ot/ObjCImprovements.h"
   6
   7 @interface CKKSListenerCollection ()
   8 @property NSString* name;
   9 @property NSMapTable<dispatch_queue_t, id>* listeners;
  10 @end
  11
  12 @implementation CKKSListenerCollection
  13
  14 - (instancetype)initWithName:(NSString*)name
  15 {
  16     if((self = [super init])) {
  17         _name = name;
  18         // Backwards from how we'd like, but it's the best way to have weak pointers to ListenerTypes.
  19         _listeners = [NSMapTable strongToWeakObjectsMapTable];
  20     }
  21     return self;
  22 }
  23
  24 - (NSString*)description
  25 {
  26     @synchronized(self.listeners) {
  27         return [NSString stringWithFormat:@"<CKKSListenerCollection(%@): %@>", self.name, [[self.listeners objectEnumerator] allObjects]];
  28     }
  29 }
  30
  31 - (void)registerListener:(id)listener
  32 {
  33     @synchronized(self.listeners) {
  34         bool alreadyRegisteredListener = false;
  35         NSEnumerator *enumerator = [self.listeners objectEnumerator];
  36         id value;
  37
  38         while ((value = [enumerator nextObject])) {
  39             // actually use pointer comparison
  40             alreadyRegisteredListener |= (value == listener);
  41         }
  42
  43         if(listener && !alreadyRegisteredListener) {
  44             NSString* queueName = [NSString stringWithFormat: @"%@-%@", self.name, listener];
  45
  46             dispatch_queue_t objQueue = dispatch_queue_create([queueName UTF8String], DISPATCH_QUEUE_SERIAL_WITH_AUTORELEASE_POOL);
  47             [self.listeners setObject: listener forKey: objQueue];
  48         }
  49     }
  50 }
  51
  52 - (void)iterateListeners:(void (^)(id))block
  53 {
  54     @synchronized(self.listeners) {
  55         NSEnumerator *enumerator = [self.listeners keyEnumerator];
  56         dispatch_queue_t dq;
  57
  58         // Queue up the changes for each listener.
  59         while ((dq = [enumerator nextObject])) {
  60             id listener = [self.listeners objectForKey: dq];
  61             WEAKIFY(listener);
  62
  63             if(listener) {
  64                 dispatch_async(dq, ^{
  65                         STRONGIFY(listener);
  66                         block(listener);
  67                 });
  68             }
  69         }
  70     }
  71 }
  72
  73 @end
  74
  75 #endif // OCTAGON