Bug 1003943 - Properly update widget cursors when the mouse passes between remote frames. r=smaug

dom/events/EventStateManager.cpp

@@ -558,6 +558,17 @@ EventStateManager::PreHandleEvent(nsPresContext* aPresContext,
     break;
   }
   case NS_MOUSE_EXIT:
+    // If this is a remote frame, we receive NS_MOUSE_EXIT from the parent
+    // the mouse exits our content. Since the parent may update the cursor
+    // while the mouse is outside our frame, and since PuppetWidget caches the
+    // current cursor internally, re-entering our content (say from over a
+    // window edge) wont update the cursor if the cached value and the current
+    // cursor match. So when the mouse exits a remote frame, clear the cached
+    // widget cursor so a proper update will occur when the mouse re-enters.
+    if (XRE_GetProcessType() == GeckoProcessType_Content) {
+      ClearCachedWidgetCursor(mCurrentTarget);
+    }
+
     // If the event is not a top-level window exit, then it's not
     // really an exit --- we may have traversed widget boundaries but
     // we're still in our toplevel window.
@@ -3329,6 +3340,19 @@ EventStateManager::UpdateCursor(nsPresContext* aPresContext,
   }
 }
 
+void
+EventStateManager::ClearCachedWidgetCursor(nsIFrame* aTargetFrame)
+{
+  if (!aTargetFrame) {
+    return;
+  }
+  nsIWidget* aWidget = aTargetFrame->GetNearestWidget();
+  if (!aWidget) {
+    return;
+  }
+  aWidget->ClearCachedCursor();
+}
+
 nsresult
 EventStateManager::SetCursor(int32_t aCursor, imgIContainer* aContainer,
                              bool aHaveHotspot,

dom/events/EventStateManager.h

@@ -271,6 +271,15 @@ protected:
    */
   static int32_t GetAccessModifierMaskFor(nsISupports* aDocShell);
 
+  /*
+   * If aTargetFrame's widget has a cached cursor value, resets the cursor
+   * such that the next call to SetCursor on the widget will force an update
+   * of the native cursor. For use in getting puppet widget to update its
+   * cursor between mouse exit / enter transitions. This call basically wraps
+   * nsIWidget ClearCachedCursor.
+   */
+  void ClearCachedWidgetCursor(nsIFrame* aTargetFrame);
+
   void UpdateCursor(nsPresContext* aPresContext,
                     WidgetEvent* aEvent,
                     nsIFrame* aTargetFrame,

dom/ipc/PBrowser.ipdl

@@ -226,7 +226,16 @@ parent:
      */
     sync GetWidgetNativeData() returns (WindowsHandle value);
 
-    SetCursor(uint32_t value);
+    /**
+     * Set the native cursor.
+     * @param value
+     *   The widget cursor to set.
+     * @param force
+     *   Invalidate any locally cached cursor settings and force an
+     *   update.
+     */
+    SetCursor(uint32_t value, bool force);
+
     SetBackgroundColor(nscolor color);
 
     /**

dom/ipc/TabParent.cpp

@@ -1017,10 +1017,13 @@ TabParent::RecvAsyncMessage(const nsString& aMessage,
 }
 
 bool
-TabParent::RecvSetCursor(const uint32_t& aCursor)
+TabParent::RecvSetCursor(const uint32_t& aCursor, const bool& aForce)
 {
   nsCOMPtr<nsIWidget> widget = GetWidget();
   if (widget) {
+    if (aForce) {
+      widget->ClearCachedCursor();
+    }
     widget->SetCursor((nsCursor) aCursor);
   }
   return true;

dom/ipc/TabParent.h

@@ -168,7 +168,7 @@ public:
                                      const int32_t& aCause,
                                      const int32_t& aFocusChange) MOZ_OVERRIDE;
     virtual bool RecvRequestFocus(const bool& aCanRaise) MOZ_OVERRIDE;
-    virtual bool RecvSetCursor(const uint32_t& aValue) MOZ_OVERRIDE;
+    virtual bool RecvSetCursor(const uint32_t& aValue, const bool& aForce) MOZ_OVERRIDE;
     virtual bool RecvSetBackgroundColor(const nscolor& aValue) MOZ_OVERRIDE;
     virtual bool RecvSetStatus(const uint32_t& aType, const nsString& aStatus) MOZ_OVERRIDE;
     virtual bool RecvIsParentWindowMainWidgetVisible(bool* aIsVisible);

widget/gtk/nsWindow.cpp

@@ -1507,8 +1507,9 @@ nsWindow::SetCursor(nsCursor aCursor)
     }
 
     // Only change cursor if it's actually been changed
-    if (aCursor != mCursor) {
+    if (aCursor != mCursor || mUpdateCursor) {
         GdkCursor *newCursor = nullptr;
+        mUpdateCursor = false;
 
         newCursor = get_gtk_cursor(aCursor);
 

widget/nsIWidget.h

@@ -100,8 +100,8 @@ typedef void* nsNativeWidget;
 #endif
 
 #define NS_IWIDGET_IID \
-{ 0x91944a4b, 0xbc29, 0x44aa, \
-  { 0x99, 0x21, 0x42, 0xeb, 0x1f, 0xbb, 0xa6, 0x89 } }
+{ 0x5b27abd6, 0x9e53, 0x4a0a, \
+  { 0x86, 0xf, 0x77, 0x5c, 0xc5, 0x69, 0x35, 0xf } };
 
 /*
  * Window shadow styles
@@ -1165,6 +1165,13 @@ class nsIWidget : public nsISupports {
 
     NS_IMETHOD SetCursor(nsCursor aCursor) = 0;
 
+    /**
+     * If a cursor type is currently cached locally for this widget, clear the
+     * cached cursor to force an update on the next SetCursor call.
+     */
+
+    virtual void ClearCachedCursor() = 0;
+
     /**
      * Sets an image as the cursor for this widget.
      *

widget/qt/nsWindow.cpp

@@ -809,10 +809,10 @@ nsWindow::GetGLFrameBufferFormat()
 NS_IMETHODIMP
 nsWindow::SetCursor(nsCursor aCursor)
 {
-    if (mCursor == aCursor) {
+    if (mCursor == aCursor && !mUpdateCursor) {
         return NS_OK;
     }
-
+    mUpdateCursor = false;
     mCursor = aCursor;
     if (mWidget) {
         mWidget->SetCursor(mCursor);

widget/xpwidgets/PuppetWidget.cpp

@@ -649,15 +649,17 @@ PuppetWidget::NotifyIMEOfSelectionChange(
 NS_IMETHODIMP
 PuppetWidget::SetCursor(nsCursor aCursor)
 {
-  if (mCursor == aCursor) {
+  if (mCursor == aCursor && !mUpdateCursor) {
     return NS_OK;
   }
 
-  if (mTabChild && !mTabChild->SendSetCursor(aCursor)) {
+  if (mTabChild &&
+      !mTabChild->SendSetCursor(aCursor, mUpdateCursor)) {
     return NS_ERROR_FAILURE;
   }
 
   mCursor = aCursor;
+  mUpdateCursor = false;
 
   return NS_OK;
 }

widget/xpwidgets/nsBaseWidget.cpp

@@ -111,6 +111,7 @@ nsBaseWidget::nsBaseWidget()
 , mAttachedWidgetListener(nullptr)
 , mContext(nullptr)
 , mCursor(eCursor_standard)
+, mUpdateCursor(true)
 , mBorderStyle(eBorderStyle_none)
 , mUseLayersAcceleration(false)
 , mForceLayersAcceleration(false)

widget/xpwidgets/nsBaseWidget.h

@@ -115,6 +115,7 @@ public:
   NS_IMETHOD              SetCursor(nsCursor aCursor);
   NS_IMETHOD              SetCursor(imgIContainer* aCursor,
                                     uint32_t aHotspotX, uint32_t aHotspotY);
+  virtual void            ClearCachedCursor() { mUpdateCursor = true; }
   virtual void            SetTransparencyMode(nsTransparencyMode aMode);
   virtual nsTransparencyMode GetTransparencyMode();
   virtual void            GetWindowClipRegion(nsTArray<nsIntRect>* aRects);
@@ -402,6 +403,7 @@ protected:
   nsRefPtr<CompositorParent> mCompositorParent;
   nsRefPtr<WidgetShutdownObserver> mShutdownObserver;
   nsCursor          mCursor;
+  bool              mUpdateCursor;
   nsBorderStyle     mBorderStyle;
   bool              mUseLayersAcceleration;
   bool              mForceLayersAcceleration;