iOS: add thread-safe handling for JSDispatcher

doric-iOS/Pod/Classes/Util/DoricJSDispatcher.m

@@ -22,10 +22,19 @@
 @interface DoricJSDispatcher ()
 @property(nonatomic, strong) NSMutableArray <DoricAsyncResult *(^)(void)> *blocks;
 @property(nonatomic, assign) BOOL consuming;
+@property(nonatomic, strong) dispatch_queue_t syncQueue;
 @end
 
 @implementation DoricJSDispatcher
+- (instancetype)init {
+    if (self = [super init]) {
+        _syncQueue = dispatch_queue_create("DoricJSDispatcher", DISPATCH_QUEUE_CONCURRENT);
+    }
+    return self;
+}
+
 - (void)dispatch:(DoricAsyncResult *(^)(void))block {
+    dispatch_barrier_async(self.syncQueue, ^{
         if (!self.blocks) {
             self.blocks = [@[block] mutableCopy];
         } else {
@@ -37,9 +46,12 @@ - (void)dispatch:(DoricAsyncResult *(^)(void))block {
         if (!self.consuming) {
             [self consume];
         }
+    });
+
 }
 
 - (void)consume {
+    dispatch_barrier_async(self.syncQueue, ^{
         DoricAsyncResult *(^block )(void) = self.blocks.lastObject;
         if (block) {
             self.consuming = YES;
@@ -55,9 +67,12 @@ - (void)consume {
         } else {
             self.consuming = NO;
         }
+    });
 }
 
 - (void)clear {
+    dispatch_barrier_async(self.syncQueue, ^{
         [self.blocks removeAllObjects];
+    });
 }
 @end