Changeset 196167 in webkit

Timestamp:

Feb 5, 2016 12:53:51 AM (8 years ago)

Author:

n_wang@apple.com

Message:

AX: WebKit hanging when VoiceOver attempts to focus in on page
​https://bugs.webkit.org/show_bug.cgi?id=153899
<rdar://problem/24506603>

Reviewed by Chris Fleizach.

Source/WebCore:

The VisiblePosition to CharacterOffset conversion will lead to an infinite loop if the
nextVisiblePostion call is returning the original VisiblePosition. Fixed it by breaking out
of the loop early in that situation.

Test: accessibility/text-marker/character-offset-visible-position-conversion-hang.html

• accessibility/AXObjectCache.cpp:

(WebCore::AXObjectCache::characterOffsetFromVisiblePosition):

LayoutTests:

• accessibility/text-marker/character-offset-visible-position-conversion-hang-expected.txt: Added.
• accessibility/text-marker/character-offset-visible-position-conversion-hang.html: Added.

Location:

trunk

Files:

• LayoutTests/ChangeLog (modified) (1 diff)
• LayoutTests/accessibility/text-marker/character-offset-visible-position-conversion-hang-expected.txt (added)
• LayoutTests/accessibility/text-marker/character-offset-visible-position-conversion-hang.html (added)
• Source/WebCore/ChangeLog (modified) (1 diff)
• Source/WebCore/accessibility/AXObjectCache.cpp (modified) (1 diff)

trunk/LayoutTests/ChangeLog

@@ +1 @@
+2016-02-05  Nan Wang  <n_wang@apple.com>
+
+        AX: WebKit hanging when VoiceOver attempts to focus in on page
+        https://bugs.webkit.org/show_bug.cgi?id=153899
+        <rdar://problem/24506603>
+
+        Reviewed by Chris Fleizach.
+
+        * accessibility/text-marker/character-offset-visible-position-conversion-hang-expected.txt: Added.
+        * accessibility/text-marker/character-offset-visible-position-conversion-hang.html: Added.
+
 2016-02-04  Joseph Pecoraro  <pecoraro@apple.com>
 

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2016-02-05  Nan Wang  <n_wang@apple.com>
+
+        AX: WebKit hanging when VoiceOver attempts to focus in on page
+        https://bugs.webkit.org/show_bug.cgi?id=153899
+        <rdar://problem/24506603>
+
+        Reviewed by Chris Fleizach.
+
+        The VisiblePosition to CharacterOffset conversion will lead to an infinite loop if the
+        nextVisiblePostion call is returning the original VisiblePosition. Fixed it by breaking out
+        of the loop early in that situation. 
+
+        Test: accessibility/text-marker/character-offset-visible-position-conversion-hang.html
+
+        * accessibility/AXObjectCache.cpp:
+        (WebCore::AXObjectCache::characterOffsetFromVisiblePosition):
+
 2016-02-04  Joseph Pecoraro  <pecoraro@apple.com>
 

trunk/Source/WebCore/accessibility/AXObjectCache.cpp

@@ -1754 +1754 @@
     Position vpDeepPos = vp.deepEquivalent();
     
+    VisiblePosition previousVisiblePos;
     while (!vpDeepPos.isNull() && !deepPos.equals(vpDeepPos)) {
+        previousVisiblePos = vp;
         vp = obj->nextVisiblePosition(vp);
         vpDeepPos = vp.deepEquivalent();
+        // Sometimes nextVisiblePosition will give the same VisiblePostion,
+        // we break here to avoid infinite loop.
+        if (vpDeepPos.equals(previousVisiblePos.deepEquivalent()))
+            break;
         characterOffset++;
     }