Compute touch actions for touch point from remote layer tree regions

https://bugs.webkit.org/show_bug.cgi?id=196701

Reviewed by Simon Fraser.

Add a function for finding the right layer and getting the touch actions in UI process side.

The code is not used yet.

* UIProcess/RemoteLayerTree/ios/RemoteLayerTreeViews.h:
* UIProcess/RemoteLayerTree/ios/RemoteLayerTreeViews.mm:
(WebKit::touchActionsForPoint):

Use the same code as overlap hit testing for collecting the candidate layers for the touch point,
taking event regions into account.
Return the touch actions from the deepest event sensitive layer hit.

(-[UIView _web_findDescendantViewAtPoint:withEvent:]):

Modernize.


Canonical link: https://commits.webkit.org/210981@main
git-svn-id: https://svn.webkit.org/repository/webkit/trunk@244042 268f45cc-cd09-0410-ab3c-d52691b4dbfc

Source/WebKit/ChangeLog

@@ -1,3 +1,26 @@
+2019-04-08  Antti Koivisto  <antti@apple.com>
+
+        Compute touch actions for touch point from remote layer tree regions
+        https://bugs.webkit.org/show_bug.cgi?id=196701
+
+        Reviewed by Simon Fraser.
+
+        Add a function for finding the right layer and getting the touch actions in UI process side.
+
+        The code is not used yet.
+
+        * UIProcess/RemoteLayerTree/ios/RemoteLayerTreeViews.h:
+        * UIProcess/RemoteLayerTree/ios/RemoteLayerTreeViews.mm:
+        (WebKit::touchActionsForPoint):
+
+        Use the same code as overlap hit testing for collecting the candidate layers for the touch point,
+        taking event regions into account.
+        Return the touch actions from the deepest event sensitive layer hit.
+
+        (-[UIView _web_findDescendantViewAtPoint:withEvent:]):
+
+        Modernize.
+
 2019-04-08  Brent Fulgham  <bfulgham@apple.com>
 
         Make HSTS list handling more robust against unexpected content 

Source/WebKit/UIProcess/RemoteLayerTree/ios/RemoteLayerTreeViews.h

@@ -72,4 +72,12 @@ class WebPageProxy;
 
 @end
 
+namespace WebKit {
+
+#if ENABLE(POINTER_EVENTS)
+OptionSet<WebCore::TouchAction> touchActionsForPoint(UIView *rootView, const WebCore::IntPoint&);
+#endif
+
+}
+
 #endif // PLATFORM(IOS_FAMILY)

Source/WebKit/UIProcess/RemoteLayerTree/ios/RemoteLayerTreeViews.mm

@@ -89,6 +89,27 @@ static bool isScrolledBy(WKChildScrollView* scrollView, UIView *hitView)
     return false;
 }
 
+#if ENABLE(POINTER_EVENTS)
+OptionSet<WebCore::TouchAction> touchActionsForPoint(UIView *rootView, const WebCore::IntPoint& point)
+{
+    Vector<UIView *, 16> viewsAtPoint;
+    collectDescendantViewsAtPoint(viewsAtPoint, rootView, point, nil);
+
+    if (viewsAtPoint.isEmpty())
+        return { WebCore::TouchAction::Auto };
+
+    auto *hitView = viewsAtPoint.last();
+
+    CGPoint hitViewPoint = [hitView convertPoint:point fromView:rootView];
+
+    auto* node = RemoteLayerTreeNode::forCALayer(hitView.layer);
+    if (!node)
+        return { WebCore::TouchAction::Auto };
+
+    return node->eventRegion().touchActionsForPoint(WebCore::IntPoint(hitViewPoint));
+}
+#endif
+
 }
 
 @interface UIView (WKHitTesting)
@@ -102,8 +123,7 @@ - (UIView *)_web_findDescendantViewAtPoint:(CGPoint)point withEvent:(UIEvent *)e
     Vector<UIView *, 16> viewsAtPoint;
     WebKit::collectDescendantViewsAtPoint(viewsAtPoint, self, point, event);
 
-    for (auto i = viewsAtPoint.size(); i--;) {
-        auto *view = viewsAtPoint[i];
+    for (auto *view : WTF::makeReversedRange(viewsAtPoint)) {
         if (!view.isUserInteractionEnabled)
             continue;