Bug 1248838 - ARIA owns change may fail, r=yzen

accessible/generic/Accessible.cpp

@@ -2130,6 +2130,51 @@ Accessible::RemoveChild(Accessible* aChild)
   return true;
 }
 
+void
+Accessible::MoveChild(uint32_t aNewIndex, Accessible* aChild)
+{
+  MOZ_ASSERT(aChild, "No child was given");
+  MOZ_ASSERT(aChild->mParent == this, "A child from different subtree was given");
+  MOZ_ASSERT(aChild->mIndexInParent != -1, "Unbound child was given");
+  MOZ_ASSERT(static_cast<uint32_t>(aChild->mIndexInParent) != aNewIndex,
+             "No move, same index");
+  MOZ_ASSERT(aNewIndex <= mChildren.Length(), "Wrong new index was given");
+
+#ifdef DEBUG
+  // AutoTreeMutation should update group info.
+  AssertInMutatingSubtree();
+#endif
+
+  mEmbeddedObjCollector = nullptr;
+  mChildren.RemoveElementAt(aChild->mIndexInParent);
+
+  uint32_t startIdx = aNewIndex, endIdx = aChild->mIndexInParent;
+
+  // If the child is moved after its current position.
+  if (static_cast<uint32_t>(aChild->mIndexInParent) < aNewIndex) {
+    startIdx = aChild->mIndexInParent;
+
+    if (aNewIndex == mChildren.Length() + 1) {
+      // The child is moved to the end.
+      mChildren.AppendElement(aChild);
+      endIdx = mChildren.Length() - 1;
+    }
+    else {
+      mChildren.InsertElementAt(aNewIndex - 1, aChild);
+      endIdx = aNewIndex;
+    }
+  }
+  else {
+    // The child is moved prior its current position.
+    mChildren.InsertElementAt(aNewIndex, aChild);
+  }
+
+  for (uint32_t idx = startIdx; idx <= endIdx; idx++) {
+    mChildren[idx]->mIndexInParent = idx;
+    mChildren[idx]->mInt.mIndexOfEmbeddedChild = -1;
+  }
+}
+
 Accessible*
 Accessible::GetChildAt(uint32_t aIndex) const
 {

accessible/generic/Accessible.h

@@ -396,6 +396,11 @@ public:
   virtual bool InsertChildAt(uint32_t aIndex, Accessible* aChild);
   virtual bool RemoveChild(Accessible* aChild);
 
+  /**
+   * Reallocates the child withing its parent.
+   */
+  void MoveChild(uint32_t aNewIndex, Accessible* aChild);
+
   //////////////////////////////////////////////////////////////////////////////
   // Accessible tree traverse methods
 

accessible/generic/DocAccessible.cpp

@@ -2058,7 +2058,10 @@ DocAccessible::DoARIAOwnsRelocation(Accessible* aOwner)
     }
 
     if (child->Parent() == aOwner) {
-      MoveChild(child, insertIdx - 1);
+      if (child->IsRelocated()) {
+        children->RemoveElement(child);
+      }
+      MoveChild(child, insertIdx);
       children->InsertElementAt(arrayIdx, child);
       arrayIdx++;
 
@@ -2141,9 +2144,7 @@ DocAccessible::MoveChild(Accessible* aChild, int32_t aIdxInParent)
   reorderEvent->AddSubMutationEvent(hideEvent);
 
   AutoTreeMutation mut(parent);
-  parent->RemoveChild(aChild);
-
-  parent->InsertChildAt(aIdxInParent, aChild);
+  parent->MoveChild(aIdxInParent, aChild);
   aChild->SetRelocated(true);
 
   FireDelayedEvent(hideEvent);
@@ -2174,6 +2175,7 @@ DocAccessible::PutChildrenBack(nsTArray<RefPtr<Accessible> >* aChildren,
       RefPtr<AccReorderEvent> reorderEvent = new AccReorderEvent(owner);
       RefPtr<AccMutationEvent> hideEvent = new AccHideEvent(child, false);
       reorderEvent->AddSubMutationEvent(hideEvent);
+      FireDelayedEvent(hideEvent);
 
       {
         AutoTreeMutation mut(owner);
@@ -2181,7 +2183,6 @@ DocAccessible::PutChildrenBack(nsTArray<RefPtr<Accessible> >* aChildren,
         child->SetRelocated(false);
       }
 
-      FireDelayedEvent(hideEvent);
       MaybeNotifyOfValueChange(owner);
       FireDelayedEvent(reorderEvent);
     }

accessible/tests/mochitest/common.js

@@ -110,6 +110,27 @@ function isLogged(aModule)
   return gAccRetrieval.isLogged(aModule);
 }
 
+/**
+ * Dumps the accessible tree into console.
+ */
+function dumpTree(aId, aMsg)
+{
+  function dumpTreeIntl(acc, indent)
+  {
+    dump(indent + prettyName(acc) + "\n");
+
+    var children = acc.children;
+    for (var i = 0; i < children.length; i++) {
+      var child = children.queryElementAt(i, nsIAccessible);
+      dumpTreeIntl(child, indent + "  ");
+    }
+  }
+
+  dump(aMsg + "\n");
+  var root = getAccessible(aId);
+  dumpTreeIntl(root, "  ");
+}
+
 /**
  * Invokes the given function when document is loaded and focused. Preferable
  * to mochitests 'addLoadEvent' function -- additionally ensures state of the

accessible/tests/mochitest/treeupdate/test_ariaowns.html

@@ -23,19 +23,21 @@
     // Invokers
     ////////////////////////////////////////////////////////////////////////////
 
-    function removeARIAOwns()
+    function changeARIAOwns()
     {
       this.eventSeq = [
-        new invokerChecker(EVENT_HIDE, getNode("t1_checkbox")),
         new invokerChecker(EVENT_HIDE, getNode("t1_button")),
         new invokerChecker(EVENT_SHOW, getNode("t1_button")),
+        new invokerChecker(EVENT_HIDE, getNode("t1_subdiv")),
+        new invokerChecker(EVENT_SHOW, getNode("t1_subdiv")),
+        new invokerChecker(EVENT_HIDE, getNode("t1_checkbox")),
         new invokerChecker(EVENT_SHOW, getNode("t1_checkbox")),
         new invokerChecker(EVENT_REORDER, getNode("t1_container"))
       ];
 
-      this.invoke = function removeARIAOwns_invoke()
+      this.invoke = function setARIAOwns_invoke()
       {
-        // children are swapped
+        // children are swapped by ARIA owns
         var tree =
           { SECTION: [
               { CHECKBUTTON: [
@@ -45,6 +47,41 @@
           ] };
         testAccessibleTree("t1_container", tree);
 
+        getNode("t1_container").
+          setAttribute("aria-owns", "t1_button t1_subdiv");
+      }
+
+      this.finalCheck = function setARIAOwns_finalCheck()
+      {
+        // children are swapped again, button and subdiv are appended to
+        // the children.
+        var tree =
+          { SECTION: [
+              { CHECKBUTTON: [ ] }, // checkbox, native order
+              { PUSHBUTTON: [ ] }, // button, rearranged by ARIA own
+              { SECTION: [ ] } // subdiv from the subtree, ARIA owned
+          ] };
+        testAccessibleTree("t1_container", tree);
+      }
+
+      this.getID = function setARIAOwns_getID()
+      {
+        return "Change @aria-owns attribute";
+      }
+    }
+
+    function removeARIAOwns()
+    {
+      this.eventSeq = [
+        new invokerChecker(EVENT_HIDE, getNode("t1_button")),
+        new invokerChecker(EVENT_HIDE, getNode("t1_subdiv")),
+        new invokerChecker(EVENT_SHOW, getNode("t1_button")),
+        new invokerChecker(EVENT_SHOW, getNode("t1_subdiv")),
+        new invokerChecker(EVENT_REORDER, getNode("t1_container"))
+      ];
+
+      this.invoke = function removeARIAOwns_invoke()
+      {
         getNode("t1_container").removeAttribute("aria-owns");
       }
 
@@ -418,6 +455,7 @@
       gQueue = new eventQueue();
 
       // test1
+      gQueue.push(new changeARIAOwns());
       gQueue.push(new removeARIAOwns());
       gQueue.push(new setARIAOwns());
       gQueue.push(new addIdToARIAOwns());