Fix for NT4 build hang

-r aaron

widget/src/build/makefile.win

@@ -56,7 +56,7 @@ WIN_LIBS=                               \
  Uuid.lib								\
  ole32.lib								\
  shell32.lib \
- oleacc.lib \
+# oleacc.lib \
  oleaut32.lib
 
 LLIBS= \

widget/src/windows/Accessible.cpp

@@ -116,10 +116,58 @@ STDMETHODIMP_(ULONG) Accessible::Release()
   return 0;
 }
 
+HINSTANCE Accessible::gmAccLib = 0;
+LPFNACCESSIBLEOBJECTFROMWINDOW Accessible::gmAccessibleObjectFromWindow = 0;
+LPFNLRESULTFROMOBJECT Accessible::gmLresultFromObject = 0;
+
 //-----------------------------------------------------
 // IAccessible methods
 //-----------------------------------------------------
 
+STDMETHODIMP Accessible::AccessibleObjectFromWindow(
+  HWND hwnd,
+  DWORD dwObjectID,
+  REFIID riid,
+  void **ppvObject)
+{
+
+  // open the dll dynamically
+    if (!gmAccLib) 
+       gmAccLib =::LoadLibrary("OLEACC.DLL");  
+
+    if (gmAccLib) {
+      if (!gmAccessibleObjectFromWindow)
+       gmAccessibleObjectFromWindow = (LPFNACCESSIBLEOBJECTFROMWINDOW)GetProcAddress(gmAccLib,"AccessibleObjectFromWindow");
+
+      return gmAccessibleObjectFromWindow(hwnd, dwObjectID, riid, ppvObject);
+    }
+    
+
+    return S_FALSE;
+}
+
+
+
+STDMETHODIMP_(LRESULT) Accessible::LresultFromObject(
+  REFIID riid,
+  WPARAM wParam,
+  LPUNKNOWN pAcc)
+{
+    // open the dll dynamically
+    if (!gmAccLib) 
+       gmAccLib =::LoadLibrary("OLEACC.DLL");  
+
+    if (gmAccLib) {
+      if (!gmAccessibleObjectFromWindow)
+       gmLresultFromObject = (LPFNLRESULTFROMOBJECT)GetProcAddress(gmAccLib,"LresultFromObject");
+
+      return gmLresultFromObject(riid,wParam,pAcc);
+    }
+
+    return 0;
+}
+
+
 STDMETHODIMP Accessible::get_accParent( IDispatch __RPC_FAR *__RPC_FAR *ppdispParent)
 {
   nsCOMPtr<nsIAccessible> parent(nsnull);
@@ -138,12 +186,13 @@ STDMETHODIMP Accessible::get_accParent( IDispatch __RPC_FAR *__RPC_FAR *ppdispPa
   if (pWnd) {
     // get the accessible.
     void* ptr = nsnull;
-    AccessibleObjectFromWindow(pWnd, OBJID_WINDOW, IID_IAccessible, &ptr);
-    IAccessible* a = (IAccessible*)ptr;
-    // got one? return it.
-    if (a) {
-      *ppdispParent = a;
-      return NS_OK;
+    if (AccessibleObjectFromWindow(pWnd, OBJID_WINDOW, IID_IAccessible, &ptr) != S_FALSE) {
+      IAccessible* a = (IAccessible*)ptr;
+      // got one? return it.
+      if (a) {
+        *ppdispParent = a;
+        return NS_OK;
+      }
     }
   }
 

widget/src/windows/Accessible.h

@@ -151,8 +151,13 @@ class Accessible : public IAccessible
         VARIANT *pVarResult, EXCEPINFO *pExcepInfo, UINT *puArgErr);
 
 
+  // NT4 does not have the oleacc that defines these methods. So we define copies here that automatically
+  // load the library only if needed.
+  static STDMETHODIMP AccessibleObjectFromWindow(HWND hwnd,DWORD dwObjectID,REFIID riid,void **ppvObject);
+  static STDMETHODIMP_(LRESULT) LresultFromObject(REFIID riid,WPARAM wParam,LPUNKNOWN pAcc);
 
-    static ULONG g_cRef;              // the cum reference count of all instances
+  
+  static ULONG g_cRef;              // the cum reference count of all instances
     ULONG        m_cRef;              // the reference count
     nsCOMPtr<nsIAccessible> mAccessible;
     nsCOMPtr<nsIAccessible> mCachedChild;
@@ -165,6 +170,12 @@ class Accessible : public IAccessible
     PRBool InState(const nsString& aStates, const char* aState);
     STDMETHODIMP GetAttribute(const char* aName, VARIANT varChild, BSTR __RPC_FAR *aString);
 
+private:
+    /// the accessible library and cached methods
+    static HINSTANCE gmAccLib;
+    static LPFNACCESSIBLEOBJECTFROMWINDOW gmAccessibleObjectFromWindow;
+    static LPFNLRESULTFROMOBJECT gmLresultFromObject;
+
 };
 
 class nsAccessibleEventMap

widget/src/windows/nsWindow.cpp

@@ -3379,7 +3379,13 @@ PRBool nsWindow::ProcessMessage(UINT msg, WPARAM wParam, LPARAM lParam, LRESULT
                mRootAccessible = new RootAccessible(acc, wnd); // ref is 0       
                mRootAccessible->AddRef();
             }
-            LRESULT lAcc = LresultFromObject(IID_IAccessible, wParam, mRootAccessible); // ref 1
+            // ask accessible to do this do it loads the library dynamically
+            LRESULT lAcc = Accessible::LresultFromObject(IID_IAccessible, wParam, mRootAccessible); // ref 1
+            if (lAcc == 0) {
+              *aRetValue = NULL;
+              return PR_FALSE;
+            }
+
             *aRetValue = lAcc;
             return PR_TRUE; // yes we handled it.
           }