Changeset 154382 in webkit

Timestamp:

Aug 21, 2013, 5:52:31 AM (13 years ago)

Author:

tonikitoo@webkit.org

Message:

Text dragging can scroll overflow:hidden boxes ​https://bugs.webkit.org/show_bug.cgi?id=119760

Reviewed by Darin Adler.
Patch by Antonio Gomes <​a1.gomes@sisa.samsung.com>

Source/WebCore:

Consider the case of the following HTML:
<div style="overflow:hidden; width: 100px; height: 100px" >

<input id="input" type="text" size=10 value="any text here!"/>
<button style="position:relative; top: 100px; left: 100px"/>

</div>

If ones starts a text selection by dragging the mouse from within the input
field, and continues to drag beyong the outer div boundary, the latter will
be scrolled no matter its overflow:hidden style.
That happens because when the autoscroll has started, it gets propagated up
to the current layer's parent layer, instead of the to current layer's enclosing
scrollable layer.

Patch fixes the issue by hardening the way scrolling is
propagated upwards when autoscroll is being performed.

RenderLayer::enclosingScrollableLayer method also got rewritten
in terms of RenderLayer tree traversing, instead of RenderObject tree.
The rewrite adds support for cross frame upwards traversal.

Test: fast/events/autoscroll-upwards-propagation.html

• rendering/RenderLayer.cpp:

(WebCore::parentLayerCrossFrame):
(WebCore::RenderLayer::enclosingScrollableLayer):
(WebCore::RenderLayer::scrollRectToVisible):

LayoutTests:

• fast/events/autoscroll-upwards-propagation-expected.txt: Added.
• fast/events/autoscroll-upwards-propagation.html: Added.

Location:

trunk

Files:

• LayoutTests/ChangeLog (modified) (1 diff)
• LayoutTests/fast/events/autoscroll-upwards-propagation-expected.txt (added)
• LayoutTests/fast/events/autoscroll-upwards-propagation.html (added)
• Source/WebCore/ChangeLog (modified) (1 diff)
• Source/WebCore/rendering/RenderLayer.cpp (modified) (2 diffs)

trunk/LayoutTests/ChangeLog

@@ +1 @@
+2013-08-19  Antonio Gomes  <a1.gomes@sisa.samsung.com>
+
+        Text dragging can scroll overflow:hidden boxes
+        https://bugs.webkit.org/show_bug.cgi?id=119760
+
+        Reviewed by Darin Adler.
+        Patch by Antonio Gomes <a1.gomes@sisa.samsung.com>
+
+        * fast/events/autoscroll-upwards-propagation-expected.txt: Added.
+        * fast/events/autoscroll-upwards-propagation.html: Added.
+
 2013-08-20  Gavin Barraclough  <barraclough@apple.com>
 

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2013-08-19  Antonio Gomes  <a1.gomes@sisa.samsung.com>
+
+        Text dragging can scroll overflow:hidden boxes
+        https://bugs.webkit.org/show_bug.cgi?id=119760
+
+        Reviewed by Darin Adler.
+
+        Consider the case of the following HTML:
+        <div style="overflow:hidden; width: 100px; height: 100px" >
+          <input id="input" type="text" size=10 value="any text here!"/>
+          <button style="position:relative; top: 100px; left: 100px"/>
+        </div>
+
+        If ones starts a text selection by dragging the mouse from within the input
+        field, and continues to drag beyong the outer div boundary, the latter will
+        be scrolled no matter its overflow:hidden style.
+        That happens because when the autoscroll has started, it gets propagated up
+        to the current layer's parent layer, instead of the to current layer's enclosing
+        scrollable layer.
+
+        Patch fixes the issue by hardening the way scrolling is
+        propagated upwards when autoscroll is being performed.
+
+        RenderLayer::enclosingScrollableLayer method also got rewritten
+        in terms of RenderLayer tree traversing, instead of RenderObject tree.
+        The rewrite adds support for cross frame upwards traversal.
+
+        Test: fast/events/autoscroll-upwards-propagation.html
+
+        * rendering/RenderLayer.cpp:
+        (WebCore::parentLayerCrossFrame):
+        (WebCore::RenderLayer::enclosingScrollableLayer):
+        (WebCore::RenderLayer::scrollRectToVisible):
+
 2013-08-20  Jer Noble  <jer.noble@apple.com>
 

trunk/Source/WebCore/rendering/RenderLayer.cpp

@@ -1380 +1380 @@
 }
 
+static RenderLayer* parentLayerCrossFrame(const RenderLayer* layer)
+{
+    ASSERT(layer);
+    if (layer->parent())
+        return layer->parent();
+
+    RenderObject* renderer = layer->renderer();
+    Document* document = renderer->document();
+    if (!document)
+        return 0;
+
+    HTMLFrameOwnerElement* ownerElement = document->ownerElement();
+    if (!ownerElement)
+        return 0;
+
+    RenderObject* ownerRenderer = ownerElement->renderer();
+    if (!ownerRenderer)
+        return 0;
+
+    return ownerRenderer->enclosingLayer();
+}
+
 RenderLayer* RenderLayer::enclosingScrollableLayer() const
 {
-    for (RenderObject* nextRenderer = renderer()->parent(); nextRenderer; nextRenderer = nextRenderer->parent()) {
-        if (nextRenderer->isBox() && toRenderBox(nextRenderer)->canBeScrolledAndHasScrollableArea())
-            return nextRenderer->enclosingLayer();
+    for (RenderLayer* nextLayer = parentLayerCrossFrame(this); nextLayer; nextLayer = parentLayerCrossFrame(nextLayer)) {
+        if (nextLayer->renderer()->isBox() && toRenderBox(nextLayer->renderer())->canBeScrolledAndHasScrollableArea())
+            return nextLayer;
     }
 
@@ -2367 +2389 @@
     }
     
+    if (renderer()->frame()->eventHandler().autoscrollInProgress())
+        parentLayer = enclosingScrollableLayer();
+
     if (parentLayer)
         parentLayer->scrollRectToVisible(newRect, alignX, alignY);