[WEEX-648][iOS]native batch for dom operations generating from JavaSc…

…ript (#1644)

* [WEEX-648][iOS]native batch for dom operations generating from javaScript

wrap a series of dom operations with beginBatch and endBatch directives, when every V-sync signal comes,
we try to ensure that the operations between beginBatch and endBatch can be performed in current V-sync,
this policy can drop frames maybe, for our policy dropping frames, we only allow 20 frames at most.

Bugs:648

* [WEEX-648][iOS] clear the count for drop frames when clear stashed operation queue

Bug: 648

* [WEEX-648] adjust max collection times to 200

* [WEEX-648][iOS] optimize code batch operations commit

* [WEEX-648][iOS] try to reduce the dispatch count for main thread

feature:648

ios/sdk/WeexSDK/Sources/Manager/WXComponentManager.h

@@ -262,4 +262,18 @@ void WXPerformBlockSyncOnComponentThread(void (^block)(void));
  */
 - (void)enumerateComponentsUsingBlock:(void (^)(WXComponent *, BOOL *stop))block;
 
+#pragma mark batch mark
+
+/**
+ a start native batch tag for a group of UI operations, company with performBatchEnd
+ @see performBatchEnd
+ */
+- (void)performBatchBegin;
+
+/**
+ an end native batch tag for a group of UI operations, company with performBatchBegin
+ @see performBatchBegin
+ */
+- (void)performBatchEnd;
+
 @end

ios/sdk/WeexSDK/Sources/Manager/WXComponentManager.mm

@@ -44,7 +44,7 @@
 static NSThread *WXComponentThread;
 
 #define WXAssertComponentExist(component)  WXAssert(component, @"component not exists")
-
+#define MAX_DROP_FRAME_FOR_BATCH   200
 
 @implementation WXComponentManager
 {
@@ -64,6 +64,7 @@ @implementation WXComponentManager
 
     pthread_mutex_t _propertyMutex;
     pthread_mutexattr_t _propertMutexAttr;
+    NSUInteger _syncUITaskCount;
 }
 
 + (instancetype)sharedManager
@@ -80,7 +81,7 @@ - (instancetype)initWithWeexInstance:(id)weexInstance
 {
     if (self = [self init]) {
         _weexInstance = weexInstance;
-
+        _syncUITaskCount = 0;
         _indexDict = [NSMapTable strongToWeakObjectsMapTable];
         _fixedComponents = [NSMutableArray wx_mutableArrayUsingWeakReferences];
         _uiTaskQueue = [NSMutableArray array];
@@ -991,13 +992,42 @@ - (void) _printFlexComponentFrame:(WXComponent *)component
 
 - (void)_syncUITasks
 {
-    NSArray<dispatch_block_t> *blocks = _uiTaskQueue;
-    _uiTaskQueue = [NSMutableArray array];
-    dispatch_async(dispatch_get_main_queue(), ^{
-        for(dispatch_block_t block in blocks) {
-            block();
+    NSInteger mismatchBeginIndex = _uiTaskQueue.count;
+    for (NSInteger i = _uiTaskQueue.count - 1;i >= 0;i --) {
+        if (_uiTaskQueue[i] == WXPerformUITaskBatchEndBlock) {
+            _syncUITaskCount = 0;
+            // clear when find the matches for end and begin tag
+            break;
         }
-    });
+        if (_uiTaskQueue[i] == WXPerformUITaskBatchBeginBlock) {
+            mismatchBeginIndex = i;
+            break;
+        }
+    }
+
+    if (mismatchBeginIndex == _uiTaskQueue.count) {
+        // here we get end tag or there are not begin and end directives
+    } else {
+        _syncUITaskCount ++;
+        // we only find begin tag but missing end tag,
+        if (_syncUITaskCount > (MAX_DROP_FRAME_FOR_BATCH)) {
+            // when the wait times come to MAX_DROP_FRAME_FOR_BATCH, we will pop all the stashed operations for user experience.
+            mismatchBeginIndex = _uiTaskQueue.count;
+            _syncUITaskCount = 0;
+        }
+    }
+
+    if (mismatchBeginIndex > 0) {
+        NSArray<dispatch_block_t> *blocks = [_uiTaskQueue subarrayWithRange:NSMakeRange(0, mismatchBeginIndex)];
+        [_uiTaskQueue removeObjectsInRange:NSMakeRange(0, mismatchBeginIndex)];
+        if (blocks.count) {
+            dispatch_async(dispatch_get_main_queue(), ^{
+                for(dispatch_block_t block in blocks) {
+                    block();
+                }
+            });
+        }
+    }
 }
 
 #pragma mark Fixed 
@@ -1051,6 +1081,27 @@ - (void)enumerateComponentsUsingBlock:(void (^)(WXComponent *, BOOL *stop))block
     }
 }
 
+static void (^WXPerformUITaskBatchBeginBlock)(void) = ^ () {
+#if DEBUG
+    WXLogDebug(@"directive BatchBeginBlock");
+#endif
+};
+static void (^WXPerformUITaskBatchEndBlock)(void) = ^ () {
+#if DEBUG
+    WXLogDebug(@"directive BatchEndBlock");
+#endif
+};
+
+- (void)performBatchBegin
+{
+    [self _addUITask:WXPerformUITaskBatchBeginBlock];
+}
+
+- (void)performBatchEnd
+{
+    [self _addUITask:WXPerformUITaskBatchEndBlock];
+}
+
 - (void)handleDisplayLink {
     [self _handleDisplayLink];
 }

ios/sdk/WeexSDK/Sources/Module/WXDomModule.m

@@ -55,6 +55,8 @@ @implementation WXDomModule
 WX_EXPORT_METHOD(@selector(addRule:rule:))
 WX_EXPORT_METHOD(@selector(getComponentRect:callback:))
 WX_EXPORT_METHOD(@selector(updateComponentData:componentData:callback:))
+WX_EXPORT_METHOD(@selector(beginBatchMark))
+WX_EXPORT_METHOD(@selector(endBatchMark))
 
 - (void)performBlockOnComponentManager:(void(^)(WXComponentManager *))block
 {
@@ -82,6 +84,20 @@ - (void)performSelectorOnRuleManager:(void(^)(void))block{
     });
 }
 
+- (void)beginBatchMark
+{
+    [self performBlockOnComponentManager:^(WXComponentManager *manager) {
+        [manager performBatchBegin];
+    }];
+}
+
+- (void)endBatchMark
+{
+    [self performBlockOnComponentManager:^(WXComponentManager * manager) {
+        [manager performBatchEnd];
+    }];
+}
+
 - (NSThread *)targetExecuteThread
 {
     return [WXComponentManager componentThread];