Bug 530070. r=jmathies

widget/src/windows/nsNativeDragTarget.cpp

@@ -62,7 +62,7 @@ static POINTL gDragLastPoint;
  */
 nsNativeDragTarget::nsNativeDragTarget(nsIWidget * aWnd)
   : m_cRef(0), mWindow(aWnd), mCanMove(PR_TRUE), mTookOwnRef(PR_FALSE),
-  mDropTargetHelper(nsnull), mDragCancelled(PR_FALSE)
+  mDropTargetHelper(nsnull)
 {
   mHWnd = (HWND)mWindow->GetNativeData(NS_NATIVE_WINDOW);
 
@@ -297,6 +297,12 @@ nsNativeDragTarget::DragOver(DWORD   grfKeyState,
     return E_FAIL;
   }
 
+  nsCOMPtr<nsIDragSession> currentDragSession;
+  mDragService->GetCurrentSession(getter_AddRefs(currentDragSession));
+  if (!currentDragSession) {
+    return S_OK;  // Drag was canceled.
+  }
+
   // without the AddRef() |this| can get destroyed in an event handler
   this->AddRef();
 
@@ -307,10 +313,8 @@ nsNativeDragTarget::DragOver(DWORD   grfKeyState,
   }
 
   mDragService->FireDragEventAtSource(NS_DRAGDROP_DRAG);
-  if (!mDragCancelled) {
-    // Now process the native drag state and then dispatch the event
-    ProcessDrag(nsnull, NS_DRAGDROP_OVER, grfKeyState, ptl, pdwEffect);
-  }
+  // Now process the native drag state and then dispatch the event
+  ProcessDrag(nsnull, NS_DRAGDROP_OVER, grfKeyState, ptl, pdwEffect);
 
   this->Release();
 
@@ -358,6 +362,22 @@ nsNativeDragTarget::DragLeave()
   return S_OK;
 }
 
+void
+nsNativeDragTarget::DragCancel()
+{
+  if (mDropTargetHelper) {
+    mDropTargetHelper->DragLeave();
+  }
+  if (mDragService) {
+    mDragService->EndDragSession(PR_FALSE);
+  }
+  // release the ref that we might have taken in DragEnter
+  if (mTookOwnRef) {
+    this->Release();
+    mTookOwnRef = PR_FALSE;
+  }
+}
+
 STDMETHODIMP
 nsNativeDragTarget::Drop(LPDATAOBJECT pData,
                          DWORD        grfKeyState,

widget/src/windows/nsNativeDragTarget.h

@@ -95,8 +95,10 @@ public:
   // E_FAIL.
   STDMETHODIMP Drop(LPDATAOBJECT pSource, DWORD grfKeyState,
                     POINTL point, DWORD* pEffect);
-
-  PRBool           mDragCancelled;
+  /**
+   * Cancel the current drag session, if any.
+   */
+  void DragCancel();
 
 protected:
 

widget/src/windows/nsWindow.cpp

@@ -33,7 +33,7 @@
  *   Masayuki Nakano <masayuki@d-toybox.com>
  *   Dainis Jonitis <Dainis_Jonitis@swh-t.lv>
  *   Christian Biesinger <cbiesinger@web.de>
- *   Mats Palmgren <mats.palmgren@bredband.net>
+ *   Mats Palmgren <matspal@gmail.com>
  *   Ningjie Chen <chenn@email.uc.edu>
  *   Jim Mathies <jmathies@mozilla.com>
  *   Kyle Huey <me@kylehuey.com>
@@ -523,10 +523,12 @@ nsWindow::Create(nsIWidget *aParent,
              aAppShell, aToolkit, aInitData);
 
   HWND parent;
-  if (nsnull != aParent) { // has a nsIWidget parent
-    parent = ((aParent) ? (HWND)aParent->GetNativeData(NS_NATIVE_WINDOW) : nsnull);
+  if (aParent) { // has a nsIWidget parent
+    parent = aParent ? (HWND)aParent->GetNativeData(NS_NATIVE_WINDOW) : NULL;
+    mParent = aParent;
   } else { // has a nsNative parent
     parent = (HWND)aNativeParent;
+    mParent = aNativeParent ? GetNSWindowPtr((HWND)aNativeParent) : nsnull;
   }
 
   if (nsnull != aInitData) {
@@ -983,6 +985,8 @@ BOOL nsWindow::SetNSWindowPtr(HWND aWnd, nsWindow * ptr)
 // Get and set parent widgets
 NS_IMETHODIMP nsWindow::SetParent(nsIWidget *aNewParent)
 {
+  mParent = aNewParent;
+
   if (aNewParent) {
     nsCOMPtr<nsIWidget> kungFuDeathGrip(this);
 
@@ -2712,6 +2716,8 @@ nsIntPoint nsWindow::WidgetToScreenOffset()
 #if !defined(WINCE) // implemented in nsWindowCE.cpp
 NS_METHOD nsWindow::EnableDragDrop(PRBool aEnable)
 {
+  NS_ASSERTION(mWnd, "nsWindow::EnableDragDrop() called after Destroy()");
+
   nsresult rv = NS_ERROR_FAILURE;
   if (aEnable) {
     if (nsnull == mNativeDragTarget) {
@@ -2731,7 +2737,7 @@ NS_METHOD nsWindow::EnableDragDrop(PRBool aEnable)
       if (S_OK == ::CoLockObjectExternal((LPUNKNOWN)mNativeDragTarget, FALSE, TRUE)) {
         rv = NS_OK;
       }
-      mNativeDragTarget->mDragCancelled = PR_TRUE;
+      mNativeDragTarget->DragCancel();
       NS_RELEASE(mNativeDragTarget);
     }
   }
@@ -6226,6 +6232,7 @@ void nsWindow::OnDestroy()
   // XXX Windows will take care of this in the proper order, and SetParent(nsnull)'s
   // remove child on the parent already took place in nsBaseWidget's Destroy call above.
   //SetParent(nsnull);
+  mParent = nsnull;
 
   // We have to destroy the native drag target before we null out our window pointer.
   EnableDragDrop(PR_FALSE);

widget/src/windows/nsWindow.h

@@ -27,6 +27,7 @@
  *   Masayuki Nakano <masayuki@d-toybox.com>
  *   Ningjie Chen <chenn@email.uc.edu>
  *   Jim Mathies <jmathies@mozilla.com>.
+ *   Mats Palmgren <matspal@gmail.com>
  *
  * Alternatively, the contents of this file may be used under the terms of
  * either the GNU General Public License Version 2 or later (the "GPL"), or
@@ -424,6 +425,7 @@ protected:
 #endif // ACCESSIBILITY
 
 protected:
+  nsCOMPtr<nsIWidget>   mParent;
   nsIntSize             mLastSize;
   nsIntPoint            mLastPoint;
   HWND                  mWnd;

xpfe/appshell/src/nsXULWindow.cpp

@@ -538,6 +538,7 @@ NS_IMETHODIMP nsXULWindow::Destroy()
   }
   if (mWindow) {
     mWindow->SetClientData(0); // nsWebShellWindow hackery
+    mWindow->Destroy();
     mWindow = nsnull;
   }