Bug 610670 - Reuse a single puppet widget. r=bz,cjones a=blocking-fennec

layout/base/nsDocumentViewer.cpp

@@ -414,6 +414,11 @@ private:
                                    PRBool               aStartAtTop);
 #endif // NS_PRINTING
 
+  // Whether we should attach to the top level widget. This is true if we
+  // are sharing/recycling a single base widget and not creating multiple
+  // child widgets.
+  PRBool ShouldAttachToTopLevel();
+
 protected:
   // These return the current shell/prescontext etc.
   nsIPresShell* GetPresShell();
@@ -1392,6 +1397,32 @@ DocumentViewerImpl::Open(nsISupports *aState, nsISHEntry *aSHEntry)
   // XXX re-enable image animations once that works correctly
 
   PrepareToStartLoad();
+
+  // When loading a page from the bfcache with puppet widgets, we do the
+  // widget attachment here (it is otherwise done in MakeWindow, which is
+  // called for non-bfcache pages in the history, but not bfcache pages).
+  // Attachment is necessary, since we get detached when another page
+  // is browsed to. That is, if we are one page A, then when we go to
+  // page B, we detach. So page A's view has no widget. If we then go
+  // back to it, and it is in the bfcache, we will use that view, which
+  // doesn't have a widget. The attach call here will properly attach us.
+  if (nsIWidget::UsePuppetWidgets() && mPresContext &&
+      ShouldAttachToTopLevel()) {
+    // If the old view is already attached to our parent, detach
+    DetachFromTopLevelWidget();
+
+    nsIViewManager *vm = GetViewManager();
+    NS_ABORT_IF_FALSE(vm, "no view manager");
+    nsIView *v;
+    nsresult rv = vm->GetRootView(v);
+    NS_ABORT_IF_FALSE(NS_SUCCEEDED(rv), "failed in getting the root view");
+    NS_ABORT_IF_FALSE(v, "no root view");
+    NS_ABORT_IF_FALSE(mParentWidget, "no mParentWidget to set");
+    v->AttachToTopLevelWidget(mParentWidget);
+
+    mAttachedToParent = PR_TRUE;
+  }
+
   return NS_OK;
 }
 
@@ -2242,30 +2273,12 @@ DocumentViewerImpl::MakeWindow(const nsSize& aSize, nsIView* aContainerView)
   if (GetIsPrintPreview())
     return NS_OK;
 
-  // Prior to creating a new widget, check to see if our parent is a base
-  // chrome ui window. If so, drop the content into that widget instead of
-  // creating a new child widget. This eliminates the main content child
-  // widget we've had forever. Also allows for the recycling of the base
-  // widget of each window, vs. creating/discarding child widgets for each
-  // MakeWindow call. (Currently only implemented in windows widgets.)
-#ifdef XP_WIN
-  nsCOMPtr<nsIDocShellTreeItem> containerItem = do_QueryReferent(mContainer);
-  if (mParentWidget && containerItem) {
-    PRInt32 docType;
-    nsWindowType winType;
-    containerItem->GetItemType(&docType);
-    mParentWidget->GetWindowType(winType);
-    if ((winType == eWindowType_toplevel ||
-         winType == eWindowType_dialog ||
-         winType == eWindowType_invisible) &&
-        docType == nsIDocShellTreeItem::typeChrome) {
+  PRBool shouldAttach = ShouldAttachToTopLevel();
+
+  if (shouldAttach) {
     // If the old view is already attached to our parent, detach
     DetachFromTopLevelWidget();
-      // Use the parent widget
-      mAttachedToParent = PR_TRUE;
   }
-  }
-#endif
 
   nsresult rv;
   mViewManager = do_CreateInstance(kViewManagerCID, &rv);
@@ -2304,9 +2317,10 @@ DocumentViewerImpl::MakeWindow(const nsSize& aSize, nsIView* aContainerView)
       initDataPtr = nsnull;
     }
 
-    if (mAttachedToParent) {
+    if (shouldAttach) {
       // Reuse the top level parent widget.
       rv = view->AttachToTopLevelWidget(mParentWidget);
+      mAttachedToParent = PR_TRUE;
     }
     else if (!aContainerView && mParentWidget) {
       rv = view->CreateWidgetForParent(mParentWidget, initDataPtr,
@@ -4029,6 +4043,37 @@ DocumentViewerImpl::SetIsPrintingInDocShellTree(nsIDocShellTreeNode* aParentNode
 }
 #endif // NS_PRINTING
 
+PRBool
+DocumentViewerImpl::ShouldAttachToTopLevel()
+{
+  if (!mParentWidget)
+    return PR_FALSE;
+
+  nsCOMPtr<nsIDocShellTreeItem> containerItem = do_QueryReferent(mContainer);
+  if (!containerItem)
+    return PR_FALSE;
+
+  // We always attach when using puppet widgets
+  if (nsIWidget::UsePuppetWidgets())
+    return PR_TRUE;
+
+#ifdef XP_WIN
+  // On windows, in the parent process we also attach, but just to
+  // chrome items
+  PRInt32 docType;
+  nsWindowType winType;
+  containerItem->GetItemType(&docType);
+  mParentWidget->GetWindowType(winType);
+  if ((winType == eWindowType_toplevel ||
+       winType == eWindowType_dialog ||
+       winType == eWindowType_invisible) &&
+      docType == nsIDocShellTreeItem::typeChrome)
+    return PR_TRUE;
+#endif
+
+  return PR_FALSE;
+}
+
 //------------------------------------------------------------
 // XXX this always returns PR_FALSE for subdocuments
 PRBool

view/src/nsView.cpp

@@ -854,7 +854,8 @@ nsresult nsIView::AttachToTopLevelWidget(nsIWidget* aWidget)
 
   // Note, the previous device context will be released. Detaching
   // will not restore the old one.
-  nsresult rv = aWidget->AttachViewToTopLevel(::AttachedHandleEvent, dx);
+  nsresult rv = aWidget->AttachViewToTopLevel(
+    nsIWidget::UsePuppetWidgets() ? ::HandleEvent : ::AttachedHandleEvent, dx);
   if (NS_FAILED(rv))
     return rv;
 

widget/public/nsIWidget.h

@@ -1330,7 +1330,6 @@ class nsIWidget : public nsISupports {
                                               PRBool aIsHorizontal,
                                               PRInt32 &aOverriddenDelta) = 0;
 
-#ifdef MOZ_IPC
     /**
      * Return true if this process shouldn't use platform widgets, and
      * so should use PuppetWidgets instead.  If this returns true, the
@@ -1339,8 +1338,15 @@ class nsIWidget : public nsISupports {
      */
     static bool
     UsePuppetWidgets()
-    { return XRE_GetProcessType() == GeckoProcessType_Content; }
+    {
+#ifdef MOZ_IPC
+      return XRE_GetProcessType() == GeckoProcessType_Content;
+#else
+      return PR_FALSE;
+#endif
+    }
 
+#ifdef MOZ_IPC
     /**
      * Allocate and return a "puppet widget" that doesn't directly
      * correlate to a platform widget; platform events and data must

widget/src/xpwidgets/PuppetWidget.cpp

@@ -276,8 +276,13 @@ PuppetWidget::DispatchEvent(nsGUIEvent* event, nsEventStatus& aStatus)
                   nsCAutoString("PuppetWidget"), nsnull);
 #endif
 
+  NS_ABORT_IF_FALSE(!mChild || mChild->mWindowType == eWindowType_popup,
+                    "Unexpected event dispatch!");
+
   aStatus = nsEventStatus_eIgnore;
-  if (mEventCallback) {
+
+  NS_ABORT_IF_FALSE(mViewCallback, "No view callback!");
+
   if (event->message == NS_COMPOSITION_START) {
     mIMEComposing = PR_TRUE;
   }
@@ -298,15 +303,11 @@ PuppetWidget::DispatchEvent(nsGUIEvent* event, nsEventStatus& aStatus)
       return NS_OK;
     break;
   }
-    aStatus = (*mEventCallback)(event);
+  aStatus = (*mViewCallback)(event);
 
   if (event->message == NS_COMPOSITION_END) {
     mIMEComposing = PR_FALSE;
   }
-  } else if (mChild) {
-    event->widget = mChild;
-    mChild->DispatchEvent(event, aStatus);
-  }
 
   return NS_OK;
 }

widget/src/xpwidgets/nsBaseWidget.cpp

@@ -301,8 +301,9 @@ nsBaseWidget::AttachViewToTopLevel(EVENT_CALLBACK aViewEventFunction,
 {
   NS_ASSERTION((mWindowType == eWindowType_toplevel ||
                 mWindowType == eWindowType_dialog ||
-                mWindowType == eWindowType_invisible),
-               "Can't attach to child?");
+                mWindowType == eWindowType_invisible ||
+                mWindowType == eWindowType_child),
+               "Can't attach to window of that type");
 
   mViewCallback = aViewEventFunction;