Bug 672175 part.3 MouseScrollHandler should manage user prefs r=jimm

widget/windows/WinMouseScrollHandler.cpp

@@ -13,11 +13,18 @@
 #include "nsWindow.h"
 #include "WinUtils.h"
 
+#include "mozilla/Preferences.h"
+
 namespace mozilla {
 namespace widget {
 
 #ifdef PR_LOGGING
 PRLogModuleInfo* gMouseScrollLog = nsnull;
+
+static const char* GetBoolName(bool aBool)
+{
+  return aBool ? "TRUE" : "FALSE";
+}
 #endif
 
 MouseScrollHandler* MouseScrollHandler::sInstance = nsnull;
@@ -159,5 +166,59 @@ MouseScrollHandler::SystemSettings::MarkDirty()
   mInitialized = false;
 }
 
+/******************************************************************************
+ *
+ * UserPrefs
+ *
+ ******************************************************************************/
+
+MouseScrollHandler::UserPrefs::UserPrefs() :
+  mInitialized(false)
+{
+  // We need to reset mouse wheel transaction when all of mousewheel related
+  // prefs are changed.
+  DebugOnly<nsresult> rv =
+    Preferences::RegisterCallback(OnChange, "mousewheel.", this);
+  MOZ_ASSERT(NS_SUCCEEDED(rv),
+    "Failed to register callback for mousewheel.");
+}
+
+MouseScrollHandler::UserPrefs::~UserPrefs()
+{
+  DebugOnly<nsresult> rv =
+    Preferences::UnregisterCallback(OnChange, "mousewheel.", this);
+  MOZ_ASSERT(NS_SUCCEEDED(rv),
+    "Failed to unregister callback for mousewheel.");
+}
+
+void
+MouseScrollHandler::UserPrefs::Init()
+{
+  if (mInitialized) {
+    return;
+  }
+
+  mInitialized = true;
+
+  mPixelScrollingEnabled =
+    Preferences::GetBool("mousewheel.enable_pixel_scrolling", true);
+  mScrollMessageHandledAsWheelMessage =
+    Preferences::GetBool("mousewheel.emulate_at_wm_scroll", false);
+
+  PR_LOG(gMouseScrollLog, PR_LOG_ALWAYS,
+    ("MouseScroll::UserPrefs::Init(): initialized, "
+       "mPixelScrollingEnabled=%s, mScrollMessageHandledAsWheelMessage=%s",
+     GetBoolName(mPixelScrollingEnabled),
+     GetBoolName(mScrollMessageHandledAsWheelMessage)));
+}
+
+void
+MouseScrollHandler::UserPrefs::MarkDirty()
+{
+  PR_LOG(gMouseScrollLog, PR_LOG_ALWAYS,
+    ("MouseScrollHandler::UserPrefs::MarkDirty(): Marking UserPrefs dirty"));
+  mInitialized = false;
+}
+
 } // namespace widget
 } // namespace mozilla

widget/windows/WinMouseScrollHandler.h

@@ -71,6 +71,48 @@ public:
 
 private:
   SystemSettings mSystemSettings;
+
+public:
+  class UserPrefs {
+  public:
+    UserPrefs();
+    ~UserPrefs();
+
+    void MarkDirty();
+
+    bool IsPixelScrollingEnabled()
+    {
+      Init();
+      return mPixelScrollingEnabled;
+    }
+
+    bool IsScrollMessageHandledAsWheelMessage()
+    {
+      Init();
+      return mScrollMessageHandledAsWheelMessage;
+    }
+
+  private:
+    void Init();
+
+    static int OnChange(const char* aPrefName, void* aClosure)
+    {
+      static_cast<UserPrefs*>(aClosure)->MarkDirty();
+      return 0;
+    }
+
+    bool mInitialized;
+    bool mPixelScrollingEnabled;
+    bool mScrollMessageHandledAsWheelMessage;
+  };
+
+  UserPrefs& GetUserPrefs()
+  {
+    return mUserPrefs;
+  }
+
+private:
+  UserPrefs mUserPrefs;
 };
 
 } // namespace widget

widget/windows/nsWindow.cpp

@@ -292,7 +292,6 @@ PRUint32        nsWindow::sOOPPPluginFocusEvent   =
 
 MSG             nsWindow::sRedirectedKeyDown;
 
-bool            nsWindow::sEnablePixelScrolling = true;
 bool            nsWindow::sNeedsToInitMouseWheelSettings = true;
 
 HWND            nsWindow::sLastMouseWheelWnd = NULL;
@@ -6312,9 +6311,6 @@ nsWindow::InitMouseWheelScrollData()
   }
   sNeedsToInitMouseWheelSettings = false;
   ResetRemainingWheelDelta();
-
-  sEnablePixelScrolling =
-    Preferences::GetBool("mousewheel.enable_pixel_scrolling", true);
 }
 
 /* static */
@@ -6422,7 +6418,8 @@ nsWindow::OnMouseWheelInternal(UINT aMessage, WPARAM aWParam, LPARAM aLParam,
   PRInt32 computedScrollAmount =
     isPageScroll ? 1 : systemSettings.GetScrollAmount(isVertical);
 
-  if (sEnablePixelScrolling) {
+  if (MouseScrollHandler::GetInstance()->
+        GetUserPrefs().IsPixelScrollingEnabled()) {
     nsMouseScrollEvent testEvent(true, NS_MOUSE_SCROLL, this);
     InitEvent(testEvent);
     testEvent.scrollFlags = isPageScroll ? nsMouseScrollEvent::kIsFullPage : 0;
@@ -7567,14 +7564,9 @@ nsWindow::OnMouseWheel(UINT aMsg, WPARAM aWParam, LPARAM aLParam,
 bool
 nsWindow::OnScroll(UINT aMsg, WPARAM aWParam, LPARAM aLParam)
 {
-  static PRInt8 sMouseWheelEmulation = -1;
+  if (aLParam ||
-  if (sMouseWheelEmulation < 0) {
+      MouseScrollHandler::GetInstance()->
-    bool emulate =
+        GetUserPrefs().IsScrollMessageHandledAsWheelMessage()) {
-      Preferences::GetBool("mousewheel.emulate_at_wm_scroll", false);
-    sMouseWheelEmulation = PRInt8(emulate);
-  }
-
-  if (aLParam || sMouseWheelEmulation) {
     // Scroll message generated by Thinkpad Trackpoint Driver or similar
     // Treat as a mousewheel message and scroll appropriately
     LRESULT retVal;

widget/windows/nsWindow.h

@@ -608,7 +608,6 @@ protected:
   // was reirected to SendInput() API by OnKeyDown().
   static MSG            sRedirectedKeyDown;
 
-  static bool sEnablePixelScrolling;
   static bool sNeedsToInitMouseWheelSettings;
   static void InitMouseWheelScrollData();