Bug 283482. MSAA events and objects in wrong HWND for CSS overflow children. r=bz, sr=roc

accessible/public/nsPIAccessNode.idl

@@ -38,9 +38,12 @@
 
 #include "nsISupports.idl"
 
+interface nsIFrame;
+
 [scriptable, uuid(b3507946-4a44-4e40-b66c-f23e320997c5)]
 interface nsPIAccessNode : nsISupports
 {
   [noscript] void init();
   [noscript] void shutdown();
+  [notxpcom] nsIFrame GetFrame();
 };

accessible/src/base/nsAccessNode.cpp

@@ -247,16 +247,25 @@ already_AddRefed<nsIAccessibleDocument> nsAccessNode::GetDocAccessible()
   return docAccessible;
 }
 
+
 nsIFrame* nsAccessNode::GetFrame()
 {
   nsCOMPtr<nsIPresShell> shell(do_QueryReferent(mWeakShell));
   if (!shell) 
     return nsnull;  
 
-  nsIFrame* frame = nsnull;
+  nsIFrame* frame;
   nsCOMPtr<nsIContent> content(do_QueryInterface(mDOMNode));
-  shell->GetPrimaryFrameFor(content, &frame);
-  return frame;
+  while (content) {
+    shell->GetPrimaryFrameFor(content, &frame);
+    if (frame) {
+      return frame;
+    }
+    nsCOMPtr<nsIContent> tempContent = content->GetParent();
+    content = tempContent;
+  }
+
+  return nsnull;
 }
 
 NS_IMETHODIMP

accessible/src/base/nsAccessNode.h

@@ -125,7 +125,6 @@ protected:
     already_AddRefed<nsIPresShell> GetPresShell();
     nsPresContext* GetPresContext();
     already_AddRefed<nsIAccessibleDocument> GetDocAccessible();
-    virtual nsIFrame* GetFrame();
 
     nsCOMPtr<nsIDOMNode> mDOMNode;
     nsCOMPtr<nsIWeakReference> mWeakShell;

accessible/src/base/nsAccessible.cpp

@@ -592,7 +592,7 @@ PRBool nsAccessible::IsPartiallyVisible(PRBool *aIsOffscreen)
   if (rectVisibility == nsRectVisibility_kVisible)
     return PR_TRUE;
 
-  *aIsOffscreen = PR_TRUE;
+  *aIsOffscreen = rectVisibility != nsRectVisibility_kZeroAreaRect;
   return PR_FALSE;
 }
 
@@ -1351,18 +1351,17 @@ nsRoleMapEntry nsAccessible::gWAIRoleMap[] =
   {"button", ROLE_PUSHBUTTON, eAggregateSubtree, 0, {0, 0, 0}, {0, 0, 0}, {0, 0, 0}},
   {"checkbox", ROLE_CHECKBUTTON, eAggregateSubtree, 0, {"checked", "true", STATE_CHECKED}, {"readonly", 0, STATE_READONLY}, {0, 0, 0}},
   {"checkbox-tristate", ROLE_CHECKBUTTON, eAggregateSubtree, 0, {"checked", "true", STATE_CHECKED}, {"checked", "mixed", STATE_MIXED}, {"readonly", 0, STATE_READONLY}},
-  {"columnheader", ROLE_COLUMNHEADER, eAggregateSubtree, STATE_SELECTABLE, {"selected", 0, STATE_SELECTED}, {0, 0, 0}, {0, 0, 0}},
+  {"columnheader", ROLE_COLUMNHEADER, eAggregateSubtree, STATE_SELECTABLE, {"selected", 0, STATE_SELECTED}, {"readonly", 0, STATE_READONLY}, {0, 0, 0}},
   {"icon", ROLE_ICON, eAggregateSubtree, 0, {0, 0, 0}, {0, 0, 0}, {0, 0, 0}},
-  {"menugroup", ROLE_MENUPOPUP, eTitleOnly, 0, {0, 0, 0}, {0, 0, 0}, {0, 0, 0}},
-  {"menupopup", ROLE_MENUPOPUP, eTitleOnly, 0, {0, 0, 0}, {0, 0, 0}, {0, 0, 0}},
+  {"menu", ROLE_MENUPOPUP, eTitleOnly, 0, {0, 0, 0}, {0, 0, 0}, {0, 0, 0}},
   {"menubar", ROLE_MENUBAR, eTitleOnly, 0, {0, 0, 0}, {0, 0, 0}, {0, 0, 0}},
   {"menuitem", ROLE_MENUITEM, eAggregateSubtree, 0, {0, 0, 0}, {0, 0, 0}, {0, 0, 0}},
   {"menuitem-checkbox", ROLE_MENUITEM, eAggregateSubtree, 0, {"checked", "true", STATE_CHECKED}, {0, 0, 0}, {0, 0, 0}},
   {"grid", ROLE_TABLE, eTitleOnly, STATE_FOCUSABLE, {"readonly", 0, STATE_READONLY}, {"multiselect", 0, STATE_EXTSELECTABLE | STATE_MULTISELECTABLE}, {0, 0, 0}},
-  {"gridcell", ROLE_CELL, eAggregateSubtree, STATE_SELECTABLE, {"selected", 0, STATE_SELECTED}, {0, 0, 0}, {0, 0, 0}},
+  {"gridcell", ROLE_CELL, eAggregateSubtree, STATE_SELECTABLE, {"selected", 0, STATE_SELECTED}, {"readonly", 0, STATE_READONLY}, {0, 0, 0}},
   {"option", ROLE_LISTITEM, eAggregateSubtree, STATE_SELECTABLE, {"selected", 0, STATE_SELECTED}, {0, 0, 0}, {0, 0, 0}},
   {"progress-meter", ROLE_PROGRESSBAR, eTitleOnly, STATE_READONLY, {"valuenow", "unknown", STATE_MIXED}, {0, 0, 0}, {0, 0, 0}},
-  {"rowheader", ROLE_ROWHEADER, eAggregateSubtree, STATE_SELECTABLE, {"selected", 0, STATE_SELECTED}, {0, 0, 0}, {0, 0, 0}},
+  {"rowheader", ROLE_ROWHEADER, eAggregateSubtree, STATE_SELECTABLE, {"selected", 0, STATE_SELECTED}, {"readonly", 0, STATE_READONLY}, {0, 0, 0}},
   {"secret-text", ROLE_PASSWORD_TEXT, eTitleOnly, STATE_PROTECTED, {0, 0, 0}, {0, 0, 0}, {0, 0, 0}}, // XXX Use ext state STATE_SINGLE_LINE
   {"select", ROLE_LIST, eTitleOnly, 0, {"readonly", 0, STATE_READONLY},  {"multiselect", 0, STATE_EXTSELECTABLE | STATE_MULTISELECTABLE}, {0, 0, 0}},
   {"slider", ROLE_SLIDER, eTitleOnly, 0, {"readonly", 0, STATE_READONLY}, {0, 0, 0}, {0, 0, 0}},

accessible/src/base/nsDocAccessible.h

@@ -105,11 +105,13 @@ class nsDocAccessible : public nsBlockAccessible,
     NS_IMETHOD Shutdown();
     NS_IMETHOD Init();
 
+    // nsPIAccessNode
+    NS_IMETHOD_(nsIFrame *) GetFrame(void);
+
   protected:
     enum EBusyState {eBusyStateUninitialized, eBusyStateLoading, eBusyStateDone};
 
     virtual void GetBoundsRect(nsRect& aRect, nsIFrame** aRelativeFrame);
-    virtual nsIFrame* GetFrame();
     virtual nsresult AddEventListeners();
     virtual nsresult RemoveEventListeners();
     void AddScrollListener();

accessible/src/html/nsHTMLLinkAccessible.h

@@ -47,10 +47,15 @@ class nsHTMLLinkAccessible : public nsLinkableAccessible
 
 public:
   nsHTMLLinkAccessible(nsIDOMNode* aDomNode, nsIWeakReference* aShell, nsIFrame *aFrame);
+  
+  // nsIAccessible
   NS_IMETHOD GetName(nsAString& _retval); 
   NS_IMETHOD GetRole(PRUint32 *_retval); 
   NS_IMETHOD GetState(PRUint32 *_retval);
-  nsIFrame *GetFrame();
+  
+  // nsPIAccessNode
+  NS_IMETHOD_(nsIFrame *) GetFrame(void);
+  
 private:
   nsIFrame *mFrame;
 };

accessible/src/html/nsHTMLTextAccessible.h

@@ -48,9 +48,14 @@ class nsHTMLTextAccessible : public nsTextAccessibleWrap
 {
 public:
   nsHTMLTextAccessible(nsIDOMNode* aDomNode, nsIWeakReference* aShell, nsIFrame *aFrame);
-  nsIFrame* GetFrame();
+  
+  // nsIAccessible
   NS_IMETHOD GetName(nsAString& _retval);
   NS_IMETHOD GetState(PRUint32 *aState);
+  
+  // nsPIAccessNode
+  NS_IMETHOD_(nsIFrame *) GetFrame(void);
+  
 private:
   nsIFrame *mFrame; // Only valid if node is not shut down (mWeakShell != null)
 };

accessible/src/msaa/nsAccessibleWrap.cpp

@@ -42,10 +42,12 @@
 #include "nsIAccessibleWin32Object.h"
 #include "nsArray.h"
 #include "nsIDOMDocument.h"
+#include "nsIFrame.h"
+#include "nsINameSpaceManager.h"
 #include "nsINodeInfo.h"
 #include "nsIPrefService.h"
 #include "nsIServiceManager.h"
-#include "nsINameSpaceManager.h"
+#include "nsIView.h"
 
 // for the COM IEnumVARIANT solution in get_AccSelection()
 #define _ATLBASE_IMPL
@@ -167,15 +169,30 @@ STDMETHODIMP nsAccessibleWrap::get_accParent( IDispatch __RPC_FAR *__RPC_FAR *pp
   if (!mWeakShell)
     return E_FAIL;  // We've been shut down
 
+  nsIFrame *frame = GetFrame();
   nsCOMPtr<nsIAccessible> xpParentAccessible;
-
   GetParent(getter_AddRefs(xpParentAccessible));
-  if (xpParentAccessible) {
-    *ppdispParent = NativeAccessible(xpParentAccessible);
-    return S_OK;
+  nsCOMPtr<nsPIAccessNode> parentAccessNode(do_QueryInterface(xpParentAccessible));
+  nsIFrame *parentFrame;
+  if (!frame || !parentAccessNode ||
+    ((parentFrame = parentAccessNode->GetFrame()) != nsnull) && (frame->GetWindow() != parentFrame->GetWindow())) {
+    // This code is essentially our implementation of WindowFromAccessibleObject,
+    // because MSAA iterates get_accParent() until it sees an object of ROLE_WINDOW
+    // to know where the window for a given accessible is. We must expose the native 
+    // window accessible that MSAA creates for us. This must be done for the document
+    // object as well as any layout that creates its own window (e.g. via overflow: scroll)
+    HWND hWnd = (HWND)frame->GetWindow()->GetNativeData(NS_NATIVE_WINDOW);
+    NS_ASSERTION(hWnd, "No window handle for window");
+    if (SUCCEEDED(AccessibleObjectFromWindow(hWnd, OBJID_WINDOW, IID_IAccessible,
+                                            (void**)ppdispParent))) {
+      return S_OK;
+    }
   }
 
-  return E_FAIL;
+  NS_ASSERTION(xpParentAccessible, "No parent accessible where we're not direct child of window");
+  *ppdispParent = NativeAccessible(xpParentAccessible);
+
+  return S_OK;
 }
 
 STDMETHODIMP nsAccessibleWrap::get_accChildCount( long __RPC_FAR *pcountChildren)

accessible/src/msaa/nsDocAccessibleWrap.cpp

@@ -43,6 +43,7 @@
 #include "nsIDOMDocumentTraversal.h"
 #include "nsIDOMNodeFilter.h"
 #include "nsIDOMTreeWalker.h"
+#include "nsIFrame.h"
 #include "nsIInterfaceRequestorUtils.h"
 #include "nsIPresShell.h"
 #include "nsISelectionController.h"
@@ -161,38 +162,6 @@ STDMETHODIMP nsDocAccessibleWrap::get_accChild(
   return nsAccessibleWrap::get_accChild(varChild, ppdispChild);
 }
 
-STDMETHODIMP nsDocAccessibleWrap::get_accParent( IDispatch __RPC_FAR *__RPC_FAR *ppdispParent)
-{
-  // MSAA expects that client area accessibles return the native accessible for 
-  // their containing window, otherwise WindowFromAccessibleObject() doesn't work.
-
-  void* wnd;
-  GetWindowHandle(&wnd);
-
-  HWND pWnd = ::GetParent(NS_REINTERPRET_CAST(HWND, wnd));
-  if (pWnd) {
-    // get the accessible.
-    void* ptr = nsnull;
-#ifdef DEBUG_aleventhal
-    printf("* Ready to call AccessibleObjectFromWindow()\n");
-#endif
-    HRESULT result = AccessibleObjectFromWindow(pWnd, OBJID_WINDOW, IID_IAccessible, &ptr);
-#ifdef DEBUG_aleventhal
-    printf("* Successfully called AccessibleObjectFromWindow()\n");
-#endif
-    if (SUCCEEDED(result)) {
-      IAccessible* msaaParentAccessible = (IAccessible*)ptr;
-      // got one? return it.
-      if (msaaParentAccessible) {
-        *ppdispParent = msaaParentAccessible;
-        return S_OK;
-      }
-    }
-  }
-
-  return E_FAIL;
-}
-
 NS_IMETHODIMP nsDocAccessibleWrap::FireToolkitEvent(PRUint32 aEvent, nsIAccessible* aAccessible, void* aData)
 {
   if (!mWeakShell) {   // Means we're not active
@@ -229,10 +198,19 @@ NS_IMETHODIMP nsDocAccessibleWrap::FireToolkitEvent(PRUint32 aEvent, nsIAccessib
     // Clear out the cache in this subtree
   }
 
-  HWND hWnd = NS_REINTERPRET_CAST(HWND, mWnd);
+  nsCOMPtr<nsPIAccessNode> privateAccessNode =
+    do_QueryInterface(aAccessible);
+  nsIFrame *frame = privateAccessNode->GetFrame();
 
-  // notify the window system
-  NotifyWinEvent(aEvent, hWnd, worldID, childID);
+  HWND hWnd = frame ? (HWND)frame->GetWindow()->GetNativeData(NS_NATIVE_WINDOW) :
+                      (HWND)mWnd;
+
+  // Gecko uses two windows for every scrollable area. One window contains
+  // scrollbars and the child window contains only the client area.
+  // Details of the 2 window system:
+  // * Scrollbar window: caret drawing window & return value for WindowFromAccessibleObject()
+  // * Client area window: text drawing window & MSAA event window
+  NotifyWinEvent(aEvent, hWnd, worldID, childID);   // Fire MSAA event for client area window
 
   return NS_OK;
 }

accessible/src/msaa/nsDocAccessibleWrap.h

@@ -88,12 +88,6 @@ public:
         /* [in] */ VARIANT varChild,
         /* [retval][out] */ IDispatch __RPC_FAR *__RPC_FAR *ppdispChild);
 
-    // Override get_accParent so that native accessible for window is 
-    // returned as parent, otherwise WindowFromAccessibleObject() doesn't work.
-    // Also necessary for MSAA SDK's accexplore.exe testing tool to work.
-    virtual /* [id][propget] */ HRESULT STDMETHODCALLTYPE get_accParent( 
-        /* [retval][out] */ IDispatch __RPC_FAR *__RPC_FAR *ppdispParent);
-
     NS_IMETHOD FireToolkitEvent(PRUint32 aEvent, nsIAccessible* aAccessible, void* aData);
     NS_IMETHOD OnLocationChange(nsIWebProgress *aWebProgress,
                                 nsIRequest *aRequest, nsIURI *location);