Revise performance measurement naming and structure (#2265)

* Revise performance measurement naming and structure

- Revises naming from LayoutSpecGeneration to LayoutSpecComputation
- Adds a struct instead of an NSDictionary to retrieve performance metrics
- Includes ASEnvironmentStatePropagateDown in LayoutSpecComputation measurements

* Revise SumScopeTimer to include enable flag

* Make struct a typedef

AsyncDisplayKit/ASDisplayNode+Beta.h

@@ -38,16 +38,15 @@ ASDISPLAYNODE_EXTERN_C_END
  */
 typedef NS_OPTIONS(NSUInteger, ASDisplayNodePerformanceMeasurementOptions) {
   ASDisplayNodePerformanceMeasurementOptionLayoutSpec = 1 << 0,
-  ASDisplayNodePerformanceMeasurementOptionLayoutGeneration = 1 << 1
+  ASDisplayNodePerformanceMeasurementOptionLayoutComputation = 1 << 1
 };
 
-/**
- * Keys to retrieve performance entries from the performance dictionary.
- */
-extern NSString *const ASDisplayNodeLayoutSpecTotalTimeKey;
-extern NSString *const ASDisplayNodeLayoutSpecNumberOfPassesKey;
-extern NSString *const ASDisplayNodeLayoutGenerationTotalTimeKey;
-extern NSString *const ASDisplayNodeLayoutGenerationNumberOfPassesKey;
+typedef struct {
+  CFTimeInterval layoutSpecTotalTime;
+  NSInteger layoutSpecNumberOfPasses;
+  CFTimeInterval layoutComputationTotalTime;
+  NSInteger layoutComputationNumberOfPasses;
+} ASDisplayNodePerformanceMeasurements;
 
 @interface ASDisplayNode (Beta)
 
@@ -94,10 +93,9 @@ extern NSString *const ASDisplayNodeLayoutGenerationNumberOfPassesKey;
 @property (nonatomic, assign) ASDisplayNodePerformanceMeasurementOptions measurementOptions;
 
 /**
- * @abstract A dictionary representing performance measurements collected.
- * @note see the constants above to retrieve relevant performance measurements
+ * @abstract A simple struct representing performance measurements collected.
  */
-@property (nonatomic, strong, readonly) NSDictionary *performanceMeasurements;
+@property (nonatomic, assign, readonly) ASDisplayNodePerformanceMeasurements performanceMeasurements;
 
 /** @name Layout Transitioning */
 

AsyncDisplayKit/ASDisplayNode.mm

@@ -38,11 +38,6 @@
 NSInteger const ASDefaultDrawingPriority = ASDefaultTransactionPriority;
 NSString * const ASRenderingEngineDidDisplayScheduledNodesNotification = @"ASRenderingEngineDidDisplayScheduledNodes";
 NSString * const ASRenderingEngineDidDisplayNodesScheduledBeforeTimestamp = @"ASRenderingEngineDidDisplayNodesScheduledBeforeTimestamp";
-NSString * const ASDisplayNodeLayoutSpecTotalTimeKey = @"ASDisplayNodeLayoutSpecTotalTime";
-NSString * const ASDisplayNodeLayoutSpecNumberOfPassesKey = @"ASDisplayNodeLayoutSpecNumberOfPasses";
-NSString * const ASDisplayNodeLayoutGenerationTotalTimeKey = @"ASDisplayNodeLayoutGenerationTotalTime";
-NSString * const ASDisplayNodeLayoutGenerationNumberOfPassesKey = @"ASDisplayNodeLayoutGenerationNumberOfPasses";
-
 
 // Forward declare CALayerDelegate protocol as the iOS 10 SDK moves CALayerDelegate from a formal delegate to a protocol.
 // We have to forward declare the protocol as this place otherwise it will not compile compiling with an Base SDK < iOS 10
@@ -1227,17 +1222,17 @@ ASLayoutableSizeHelperForwarding
   return _measurementOptions;
 }
 
-- (NSDictionary *)performanceMeasurements
+- (ASDisplayNodePerformanceMeasurements)performanceMeasurements
 {
   ASDN::MutexLocker l(__instanceLock__);
-  NSMutableDictionary *measurements = [NSMutableDictionary dictionaryWithCapacity:4];
+  ASDisplayNodePerformanceMeasurements measurements = { .layoutSpecNumberOfPasses = -1, .layoutSpecTotalTime = NAN, .layoutComputationNumberOfPasses = -1, .layoutComputationTotalTime = NAN };
   if (_measurementOptions & ASDisplayNodePerformanceMeasurementOptionLayoutSpec) {
-    measurements[ASDisplayNodeLayoutSpecTotalTimeKey] = @(_layoutSpecTotalTime);
-    measurements[ASDisplayNodeLayoutSpecNumberOfPassesKey] = @(_layoutSpecNumberOfPasses);
+    measurements.layoutSpecNumberOfPasses = _layoutSpecNumberOfPasses;
+    measurements.layoutSpecTotalTime = _layoutSpecTotalTime;
   }
-  if (_measurementOptions & ASDisplayNodePerformanceMeasurementOptionLayoutGeneration) {
-    measurements[ASDisplayNodeLayoutGenerationTotalTimeKey] = @(_layoutGenerationTotalTime);
-    measurements[ASDisplayNodeLayoutGenerationNumberOfPassesKey] = @(_layoutGenerationNumberOfPasses);
+  if (_measurementOptions & ASDisplayNodePerformanceMeasurementOptionLayoutComputation) {
+    measurements.layoutComputationNumberOfPasses = _layoutComputationNumberOfPasses;
+    measurements.layoutComputationTotalTime = _layoutComputationTotalTime;
   }
   return measurements;
 }
@@ -2433,34 +2428,37 @@ void recursivelyTriggerDisplayForLayer(CALayer *layer, BOOL shouldBlock)
 
   ASDN::MutexLocker l(__instanceLock__);
   if ((_methodOverrides & ASDisplayNodeMethodOverrideLayoutSpecThatFits) || _layoutSpecBlock != NULL) {
-    ASLayoutSpec *layoutSpec = nil;
-    // optional performance measurement for cell nodes
-    if (_measurementOptions & ASDisplayNodePerformanceMeasurementOptionLayoutSpec) {
-      ASDN::SumScopeTimer t(_layoutSpecTotalTime);
+    BOOL measureLayoutSpec = _measurementOptions & ASDisplayNodePerformanceMeasurementOptionLayoutSpec;
+    if (measureLayoutSpec) {
       _layoutSpecNumberOfPasses++;
-      layoutSpec = [self layoutSpecThatFits:constrainedSize];
-    } else {
-      layoutSpec = [self layoutSpecThatFits:constrainedSize];
     }
 
+    ASLayoutSpec *layoutSpec = ({
+      ASDN::SumScopeTimer t(_layoutSpecTotalTime, measureLayoutSpec);
+      [self layoutSpecThatFits:constrainedSize];
+    });
+
     ASDisplayNodeAssert(layoutSpec.isMutable, @"Node %@ returned layout spec %@ that has already been used. Layout specs should always be regenerated.", self, layoutSpec);
 
     layoutSpec.parent = self; // This causes upward propogation of any non-default layoutable values.
     
     // manually propagate the trait collection here so that any layoutSpec children of layoutSpec will get a traitCollection
-    ASEnvironmentStatePropagateDown(layoutSpec, self.environmentTraitCollection);
+    {
+      ASDN::SumScopeTimer t(_layoutSpecTotalTime, measureLayoutSpec);
+      ASEnvironmentStatePropagateDown(layoutSpec, self.environmentTraitCollection);
+    }
     
     layoutSpec.isMutable = NO;
-    ASLayout *layout = nil;
-    // optional performance measurement for cell nodes
-    if (_measurementOptions & ASDisplayNodePerformanceMeasurementOptionLayoutGeneration) {
-      ASDN::SumScopeTimer t(_layoutGenerationTotalTime);
-      _layoutGenerationNumberOfPasses++;
-      layout = [layoutSpec layoutThatFits:constrainedSize];
-    } else {
-      layout = [layoutSpec layoutThatFits:constrainedSize];
+    BOOL measureLayoutComputation = _measurementOptions & ASDisplayNodePerformanceMeasurementOptionLayoutComputation;
+    if (measureLayoutComputation) {
+      _layoutComputationNumberOfPasses++;
     }
 
+    ASLayout *layout = ({
+      ASDN::SumScopeTimer t(_layoutComputationTotalTime, measureLayoutComputation);
+      [layoutSpec layoutThatFits:constrainedSize];
+    });
+
     ASDisplayNodeAssertNotNil(layout, @"[ASLayoutSpec measureWithSizeRange:] should never return nil! %@, %@", self, layoutSpec);
       
     // Make sure layoutableObject of the root layout is `self`, so that the flattened layout will be structurally correct.

AsyncDisplayKit/Private/ASDisplayNodeInternal.h

@@ -171,9 +171,9 @@ FOUNDATION_EXPORT NSString * const ASRenderingEngineDidDisplayNodesScheduledBefo
   // performance measurement
   ASDisplayNodePerformanceMeasurementOptions _measurementOptions;
   NSTimeInterval _layoutSpecTotalTime;
-  NSUInteger _layoutSpecNumberOfPasses;
-  NSTimeInterval _layoutGenerationTotalTime;
-  NSUInteger _layoutGenerationNumberOfPasses;
+  NSInteger _layoutSpecNumberOfPasses;
+  NSTimeInterval _layoutComputationTotalTime;
+  NSInteger _layoutComputationNumberOfPasses;
 
 #if TIME_DISPLAYNODE_OPS
 @public

AsyncDisplayKit/Private/_ASScopeTimer.h

@@ -42,11 +42,16 @@ namespace ASDN {
   struct SumScopeTimer {
     NSTimeInterval begin;
     NSTimeInterval &outT;
-    SumScopeTimer(NSTimeInterval &outRef) : outT(outRef) {
-      begin = CACurrentMediaTime();
+    BOOL enable;
+    SumScopeTimer(NSTimeInterval &outRef, BOOL enable = YES) : outT(outRef), enable(enable) {
+      if (enable) {
+        begin = CACurrentMediaTime();
+      }
     }
     ~SumScopeTimer() {
-      outT += CACurrentMediaTime() - begin;
+      if (enable) {
+        outT += CACurrentMediaTime() - begin;
+      }
     }
   };
 }