Revert "Revert "Revert "[ios_platform_view] MaskView pool to reuse maskViews. (#38989)" (#39490)" (#39498)"

This reverts commit 4270d74.

Author: Chris Yang

shell/platform/darwin/ios/framework/Source/FlutterPlatformViews.mm

@@ -18,8 +18,6 @@
 #import "flutter/shell/platform/darwin/ios/framework/Source/FlutterViewController_Internal.h"
 #import "flutter/shell/platform/darwin/ios/ios_surface.h"
 
-static const NSUInteger kFlutterClippingMaskViewPoolCapacity = 5;
-
 @implementation UIView (FirstResponder)
 - (BOOL)flt_hasFirstResponderInViewHierarchySubtree {
   if (self.isFirstResponder) {
@@ -454,17 +452,6 @@ static bool ClipRRectContainsPlatformViewBoundingRect(const SkRRect& clip_rrect,
   return clipCount;
 }
 
-void FlutterPlatformViewsController::ClipViewSetMaskView(UIView* clipView) {
-  if (clipView.maskView) {
-    return;
-  }
-  UIView* flutterView = flutter_view_.get();
-  CGRect frame =
-      CGRectMake(-clipView.frame.origin.x, -clipView.frame.origin.y,
-                 CGRectGetWidth(flutterView.bounds), CGRectGetHeight(flutterView.bounds));
-  clipView.maskView = [mask_view_pool_.get() getMaskViewWithFrame:frame];
-}
-
 void FlutterPlatformViewsController::ApplyMutators(const MutatorsStack& mutators_stack,
                                                    UIView* embedded_view,
                                                    const SkRect& bounding_rect) {
@@ -475,15 +462,18 @@ static bool ClipRRectContainsPlatformViewBoundingRect(const SkRRect& clip_rrect,
   ResetAnchor(embedded_view.layer);
   ChildClippingView* clipView = (ChildClippingView*)embedded_view.superview;
 
+  CGFloat screenScale = [UIScreen mainScreen].scale;
+
+  UIView* flutter_view = flutter_view_.get();
+  FlutterClippingMaskView* maskView = [[[FlutterClippingMaskView alloc]
+      initWithFrame:CGRectMake(-clipView.frame.origin.x, -clipView.frame.origin.y,
+                               CGRectGetWidth(flutter_view.bounds),
+                               CGRectGetHeight(flutter_view.bounds))
+        screenScale:screenScale] autorelease];
+
   SkMatrix transformMatrix;
   NSMutableArray* blurFilters = [[[NSMutableArray alloc] init] autorelease];
-  FML_DCHECK(!clipView.maskView ||
-             [clipView.maskView isKindOfClass:[FlutterClippingMaskView class]]);
-  if (mask_view_pool_.get() == nil) {
-    mask_view_pool_.reset([[FlutterClippingMaskViewPool alloc]
-        initWithCapacity:kFlutterClippingMaskViewPoolCapacity]);
-  }
-  [mask_view_pool_.get() recycleMaskViews];
+
   clipView.maskView = nil;
   CGFloat screenScale = [UIScreen mainScreen].scale;
   auto iter = mutators_stack.Begin();
@@ -498,28 +488,25 @@ static bool ClipRRectContainsPlatformViewBoundingRect(const SkRRect& clip_rrect,
                                                      transformMatrix)) {
           break;
         }
-        ClipViewSetMaskView(clipView);
-        [(FlutterClippingMaskView*)clipView.maskView clipRect:(*iter)->GetRect()
-                                                       matrix:transformMatrix];
+        [maskView clipRect:(*iter)->GetRect() matrix:transformMatrix];
+        clipView.maskView = maskView;
         break;
       }
       case kClipRRect: {
         if (ClipRRectContainsPlatformViewBoundingRect((*iter)->GetRRect(), bounding_rect,
                                                       transformMatrix)) {
           break;
         }
-        ClipViewSetMaskView(clipView);
-        [(FlutterClippingMaskView*)clipView.maskView clipRRect:(*iter)->GetRRect()
-                                                        matrix:transformMatrix];
+        [maskView clipRRect:(*iter)->GetRRect() matrix:transformMatrix];
+        clipView.maskView = maskView;
         break;
       }
       case kClipPath: {
         // TODO(cyanglaz): Find a way to pre-determine if path contains the PlatformView boudning
         // rect. See `ClipRRectContainsPlatformViewBoundingRect`.
         // https://github.com/flutter/flutter/issues/118650
-        ClipViewSetMaskView(clipView);
-        [(FlutterClippingMaskView*)clipView.maskView clipPath:(*iter)->GetPath()
-                                                       matrix:transformMatrix];
+        [maskView clipPath:(*iter)->GetPath() matrix:transformMatrix];
+        clipView.maskView = maskView;
         break;
       }
       case kOpacity:

shell/platform/darwin/ios/framework/Source/FlutterPlatformViewsTest.mm

@@ -2455,125 +2455,6 @@ - (void)testHasFirstResponderInViewHierarchySubtree_descendantViewBecomesFirstRe
   XCTAssertFalse(view.flt_hasFirstResponderInViewHierarchySubtree);
 }
 
-- (void)testFlutterClippingMaskViewPoolReuseViewsAfterRecycle {
-  FlutterClippingMaskViewPool* pool =
-      [[[FlutterClippingMaskViewPool alloc] initWithCapacity:2] autorelease];
-  FlutterClippingMaskView* view1 = [pool getMaskViewWithFrame:CGRectZero];
-  FlutterClippingMaskView* view2 = [pool getMaskViewWithFrame:CGRectZero];
-  [pool recycleMaskViews];
-  CGRect newRect = CGRectMake(0, 0, 10, 10);
-  FlutterClippingMaskView* view3 = [pool getMaskViewWithFrame:newRect];
-  FlutterClippingMaskView* view4 = [pool getMaskViewWithFrame:newRect];
-  XCTAssertEqual(view1, view3);
-  XCTAssertEqual(view2, view4);
-  XCTAssertTrue(CGRectEqualToRect(view3.frame, newRect));
-  XCTAssertTrue(CGRectEqualToRect(view4.frame, newRect));
-}
-
-- (void)testFlutterClippingMaskViewPoolAllocsNewMaskViewsAfterReachingCapacity {
-  FlutterClippingMaskViewPool* pool =
-      [[[FlutterClippingMaskViewPool alloc] initWithCapacity:2] autorelease];
-  FlutterClippingMaskView* view1 = [pool getMaskViewWithFrame:CGRectZero];
-  FlutterClippingMaskView* view2 = [pool getMaskViewWithFrame:CGRectZero];
-  FlutterClippingMaskView* view3 = [pool getMaskViewWithFrame:CGRectZero];
-  XCTAssertNotEqual(view1, view3);
-  XCTAssertNotEqual(view2, view3);
-}
-
-- (void)testMaskViewsReleasedWhenPoolIsReleased {
-  UIView* retainedView;
-  @autoreleasepool {
-    FlutterClippingMaskViewPool* pool =
-        [[[FlutterClippingMaskViewPool alloc] initWithCapacity:2] autorelease];
-    FlutterClippingMaskView* view = [pool getMaskViewWithFrame:CGRectZero];
-    retainedView = [view retain];
-    XCTAssertGreaterThan(retainedView.retainCount, 1u);
-  }
-  // The only retain left is our manual retain called inside the autorelease pool, meaning the
-  // maskViews are dealloc'd.
-  XCTAssertEqual(retainedView.retainCount, 1u);
-}
-
-- (void)testClipMaskViewIsReused {
-  flutter::FlutterPlatformViewsTestMockPlatformViewDelegate mock_delegate;
-  auto thread_task_runner = CreateNewThread("FlutterPlatformViewsTest");
-  flutter::TaskRunners runners(/*label=*/self.name.UTF8String,
-                               /*platform=*/thread_task_runner,
-                               /*raster=*/thread_task_runner,
-                               /*ui=*/thread_task_runner,
-                               /*io=*/thread_task_runner);
-  auto flutterPlatformViewsController = std::make_shared<flutter::FlutterPlatformViewsController>();
-  auto platform_view = std::make_unique<flutter::PlatformViewIOS>(
-      /*delegate=*/mock_delegate,
-      /*rendering_api=*/flutter::IOSRenderingAPI::kSoftware,
-      /*platform_views_controller=*/flutterPlatformViewsController,
-      /*task_runners=*/runners);
-
-  FlutterPlatformViewsTestMockFlutterPlatformFactory* factory =
-      [[FlutterPlatformViewsTestMockFlutterPlatformFactory new] autorelease];
-  flutterPlatformViewsController->RegisterViewFactory(
-      factory, @"MockFlutterPlatformView",
-      FlutterPlatformViewGestureRecognizersBlockingPolicyEager);
-  FlutterResult result = ^(id result) {
-  };
-  flutterPlatformViewsController->OnMethodCall(
-      [FlutterMethodCall
-          methodCallWithMethodName:@"create"
-                         arguments:@{@"id" : @1, @"viewType" : @"MockFlutterPlatformView"}],
-      result);
-
-  XCTAssertNotNil(gMockPlatformView);
-  UIView* mockFlutterView = [[[UIView alloc] initWithFrame:CGRectMake(0, 0, 10, 10)] autorelease];
-  flutterPlatformViewsController->SetFlutterView(mockFlutterView);
-  // Create embedded view params
-  flutter::MutatorsStack stack1;
-  // Layer tree always pushes a screen scale factor to the stack
-  SkMatrix screenScaleMatrix =
-      SkMatrix::Scale([UIScreen mainScreen].scale, [UIScreen mainScreen].scale);
-  stack1.PushTransform(screenScaleMatrix);
-  // Push a clip rect
-  SkRect rect = SkRect::MakeXYWH(2, 2, 3, 3);
-  stack1.PushClipRect(rect);
-
-  auto embeddedViewParams1 = std::make_unique<flutter::EmbeddedViewParams>(
-      screenScaleMatrix, SkSize::Make(10, 10), stack1);
-
-  flutter::MutatorsStack stack2;
-  auto embeddedViewParams2 = std::make_unique<flutter::EmbeddedViewParams>(
-      screenScaleMatrix, SkSize::Make(10, 10), stack2);
-
-  flutterPlatformViewsController->PrerollCompositeEmbeddedView(1, std::move(embeddedViewParams1));
-  flutterPlatformViewsController->CompositeEmbeddedView(1);
-  UIView* childClippingView1 = gMockPlatformView.superview.superview;
-  UIView* maskView1 = childClippingView1.maskView;
-  XCTAssertNotNil(maskView1);
-
-  // Composite a new frame.
-  auto embeddedViewParams3 = std::make_unique<flutter::EmbeddedViewParams>(
-      screenScaleMatrix, SkSize::Make(10, 10), stack2);
-  flutterPlatformViewsController->PrerollCompositeEmbeddedView(1, std::move(embeddedViewParams3));
-  flutterPlatformViewsController->CompositeEmbeddedView(1);
-  childClippingView1 = gMockPlatformView.superview.superview;
-
-  // This overrides gMockPlatformView to point to the newly created platform view.
-  flutterPlatformViewsController->OnMethodCall(
-      [FlutterMethodCall
-          methodCallWithMethodName:@"create"
-                         arguments:@{@"id" : @2, @"viewType" : @"MockFlutterPlatformView"}],
-      result);
-
-  auto embeddedViewParams4 = std::make_unique<flutter::EmbeddedViewParams>(
-      screenScaleMatrix, SkSize::Make(10, 10), stack1);
-  flutterPlatformViewsController->PrerollCompositeEmbeddedView(2, std::move(embeddedViewParams4));
-  flutterPlatformViewsController->CompositeEmbeddedView(2);
-  UIView* childClippingView2 = gMockPlatformView.superview.superview;
-
-  UIView* maskView2 = childClippingView2.maskView;
-  XCTAssertEqual(maskView1, maskView2);
-  XCTAssertNotNil(childClippingView2.maskView);
-  XCTAssertNil(childClippingView1.maskView);
-}
-
 // Return true if a correct visual effect view is found. It also implies all the validation in this
 // method passes.
 //

shell/platform/darwin/ios/framework/Source/FlutterPlatformViews_Internal.h

@@ -30,8 +30,6 @@
 
 - (instancetype)initWithFrame:(CGRect)frame screenScale:(CGFloat)screenScale;
 
-- (void)reset;
-
 // Adds a clip rect operation to the queue.
 //
 // The `clipSkRect` is transformed with the `matrix` before adding to the queue.
@@ -49,28 +47,6 @@
 
 @end
 
-// A pool that provides |FlutterClippingMaskView|s.
-//
-// The pool has a capacity that can be set in the initializer.
-// When requesting a FlutterClippingMaskView, the pool will first try to reuse an available maskView
-// in the pool. If there are none available, a new FlutterClippingMaskView is constructed. If the
-// capacity is reached, the newly constructed FlutterClippingMaskView is not added to the pool.
-//
-// Call |recycleMaskViews| to mark all the FlutterClippingMaskViews in the pool available.
-@interface FlutterClippingMaskViewPool : NSObject
-
-// Initialize the pool with `capacity`. When the `capacity` is reached, a FlutterClippingMaskView is
-// constructed when requested, and it is not added to the pool.
-- (instancetype)initWithCapacity:(NSInteger)capacity;
-
-// Reuse a maskView from the pool, or allocate a new one.
-- (FlutterClippingMaskView*)getMaskViewWithFrame:(CGRect)frame;
-
-// Mark all the maskViews available.
-- (void)recycleMaskViews;
-
-@end
-
 // An object represents a blur filter.
 //
 // This object produces a `backdropFilterView`.
@@ -292,7 +268,6 @@ class FlutterPlatformViewsController {
   // Traverse the `mutators_stack` and return the number of clip operations.
   int CountClips(const MutatorsStack& mutators_stack);
 
-  void ClipViewSetMaskView(UIView* clipView);
   // Applies the mutators in the mutators_stack to the UIView chain that was constructed by
   // `ReconstructClipViewsChain`
   //
@@ -353,7 +328,6 @@ class FlutterPlatformViewsController {
   fml::scoped_nsobject<FlutterMethodChannel> channel_;
   fml::scoped_nsobject<UIView> flutter_view_;
   fml::scoped_nsobject<UIViewController> flutter_view_controller_;
-  fml::scoped_nsobject<FlutterClippingMaskViewPool> mask_view_pool_;
   std::map<std::string, fml::scoped_nsobject<NSObject<FlutterPlatformViewFactory>>> factories_;
   std::map<int64_t, fml::scoped_nsobject<NSObject<FlutterPlatformView>>> views_;
   std::map<int64_t, fml::scoped_nsobject<FlutterTouchInterceptingView>> touch_interceptors_;

shell/platform/darwin/ios/framework/Source/FlutterPlatformViews_Internal.mm

@@ -271,10 +271,6 @@ - (instancetype)initWithFrame:(CGRect)frame screenScale:(CGFloat)screenScale {
   return self;
 }
 
-- (void)reset {
-  paths_.clear();
-}
-
 // In some scenarios, when we add this view as a maskView of the ChildClippingView, iOS added
 // this view as a subview of the ChildClippingView.
 // This results this view blocking touch events on the ChildClippingView.
@@ -451,66 +447,3 @@ - (void)clipPath:(const SkPath&)path matrix:(const SkMatrix&)matrix {
 }
 
 @end
-
-@interface FlutterClippingMaskViewPool ()
-
-// The maximum number of `FlutterClippingMaskView` the pool can contain.
-// This prevents the pool to grow infinately and limits the maximum memory a pool can use.
-@property(assign, nonatomic) NSUInteger capacity;
-@property(retain, nonatomic) NSMutableArray<FlutterClippingMaskView*>* pool;
-// The index points to the first available FlutterClippingMaskView in the `pool`.
-@property(assign, nonatomic) NSUInteger availableIndex;
-
-@end
-
-@implementation FlutterClippingMaskViewPool : NSObject
-
-- (instancetype)initWithCapacity:(NSInteger)capacity {
-  if (self = [super init]) {
-    _pool = [[NSMutableArray alloc] initWithCapacity:capacity];
-    _capacity = capacity;
-    _availableIndex = 0;
-  }
-  return self;
-}
-
-- (FlutterClippingMaskView*)getMaskViewWithFrame:(CGRect)frame {
-  FML_DCHECK(self.availableIndex <= self.capacity);
-  FlutterClippingMaskView* maskView;
-  if (self.availableIndex == self.capacity) {
-    // The pool is full, alloc a new one.
-    maskView =
-        [[[FlutterClippingMaskView alloc] initWithFrame:frame
-                                            screenScale:[UIScreen mainScreen].scale] autorelease];
-    return maskView;
-  }
-
-  if (self.availableIndex >= self.pool.count) {
-    // The pool doesn't have enough maskViews, alloc a new one and add to the pool.
-    maskView =
-        [[[FlutterClippingMaskView alloc] initWithFrame:frame
-                                            screenScale:[UIScreen mainScreen].scale] autorelease];
-    [self.pool addObject:maskView];
-    FML_DCHECK(self.pool.count <= self.capacity);
-  } else {
-    // Reuse a maskView from the pool.
-    maskView = [self.pool objectAtIndex:self.availableIndex];
-    maskView.frame = frame;
-    [maskView reset];
-  }
-  self.availableIndex++;
-  return maskView;
-}
-
-- (void)recycleMaskViews {
-  self.availableIndex = 0;
-}
-
-- (void)dealloc {
-  [_pool release];
-  _pool = nil;
-
-  [super dealloc];
-}
-
-@end