Fix for bug 102797: remove call to EventAvail, firstly because it is redundant (WaitNextEvent will return promptly if there is an event to handle), and because it nullifies the effects of an earlier WakeUpProcess call, which can kill performance in some areas. r=sdagley, sr=scc.

git-svn-id: svn://10.0.0.236/trunk@126579 18797224-902f-48f8-a5cc-f745e15eee43

mozilla/widget/src/mac/nsMacMessagePump.cpp

@@ -365,24 +365,20 @@ PRBool nsMacMessagePump::BrowserIsBusy()
  *  @param   NONE
  *  @return  A boolean which states whether we have a real event
  */
-#define kEventAvailMask     (mDownMask | mUpMask | keyDownMask | keyUpMask | autoKeyMask | updateMask | activMask | osMask)
-
 PRBool nsMacMessagePump::GetEvent(EventRecord &theEvent)
 {
-  // Make sure we call WNE if we have user events, or the mouse is down
-  EventRecord tempEvent;
-  // When checking btnState make sure to test if we're in the background
-  PRBool havePendingEvent =
-    ::EventAvail(kEventAvailMask, &tempEvent) ||
-    (!(tempEvent.modifiers & btnState) && nsToolkit::IsAppInForeground());
+  PRBool inForeground = nsToolkit::IsAppInForeground();
+  PRBool buttonDown   = ::Button();
   
   // when in the background, we don't want to chew up time processing mouse move
   // events, so set the mouse region to null. If we're in the fg, however,
   // we want every mouseMove event we can get our grubby little hands on, so set
   // it to a 1x1 rect.
-  RgnHandle mouseRgn = nsToolkit::IsAppInForeground() ? mMouseRgn : nsnull;
+  RgnHandle mouseRgn = inForeground ? mMouseRgn : nsnull;
 
-  SInt32  sleepTime = (havePendingEvent) ? 0 : 5;
+  // if the mouse is down, and we're in the foreground, then eat
+  // CPU so we respond quickly when scrolling etc.
+  SInt32  sleepTime = (buttonDown && inForeground) ? 0 : 5;
   
   ::SetEventMask(everyEvent); // we need keyUp events
   PRBool haveEvent = ::WaitNextEvent(everyEvent, &theEvent, sleepTime, mouseRgn);