From: Vadim Zeitlin <vadim@wxwidgets.org>
Date: Fri, 3 Feb 2012 00:21:45 +0000 (+0000)
Subject: Fix bug with mouse wheel scrolling wxStyledTextCtrl in long running programs.
X-Git-Url: https://git.saurik.com/wxWidgets.git/commitdiff_plain/7bd2132891238da6237dd5ba480fb60bba5975d4

Fix bug with mouse wheel scrolling wxStyledTextCtrl in long running programs.

In long running programs the wxEvent time stamp could wrap around resulting in
all mouse wheel events being ignored in wxStyledTextCtrl as the comparison of
the (positive) time until which all the subsequent events were supposed to be
blocked and the (now negative) current event time stamp would be always false.

Fix this by using wxStopWatch::TimeInMicro() to avoid wraparound instead of
wxEvent::GetTimestamp().

Also rename the variable to have a more clear name as the original code wasn't
easy to understand.

Closes #9057.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@70500 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
---

diff --git a/include/wx/stc/stc.h b/include/wx/stc/stc.h
index 559f8823d4..26ee4d5eba 100644
--- a/include/wx/stc/stc.h
+++ b/include/wx/stc/stc.h
@@ -4292,9 +4292,8 @@ protected:
 
     bool                m_lastKeyDownConsumed;
 
-    // the timestamp that consists of the last wheel event
-    // added to the time taken to process that event.
-    long m_lastWheelTimestamp;
+    // Time until when we should ignore any new mouse wheel events.
+    wxLongLong m_timeToBlockWheelEventsUntil;
 
     friend class ScintillaWX;
     friend class Platform;
diff --git a/src/stc/stc.cpp b/src/stc/stc.cpp
index c31f350f55..65713e1b49 100644
--- a/src/stc/stc.cpp
+++ b/src/stc/stc.cpp
@@ -199,7 +199,7 @@ bool wxStyledTextCtrl::Create(wxWindow *parent,
     m_swx = new ScintillaWX(this);
     m_stopWatch.Start();
     m_lastKeyDownConsumed = false;
-    m_lastWheelTimestamp = 0;
+    m_timeToBlockWheelEventsUntil = 0;
     m_vScrollBar = NULL;
     m_hScrollBar = NULL;
 #if wxUSE_UNICODE
@@ -4264,18 +4264,24 @@ void wxStyledTextCtrl::OnContextMenu(wxContextMenuEvent& evt) {
 
 void wxStyledTextCtrl::OnMouseWheel(wxMouseEvent& evt)
 {
-    // prevent having an event queue with wheel events that cannot be processed
-    // reasonably fast (see ticket #9057)
-    if ( m_lastWheelTimestamp <= evt.GetTimestamp() )
+    // Prevent having an event queue with wheel events that cannot be processed
+    // reasonably fast (see ticket #9057) by ignoring all of them that happen
+    // during the time interval corresponding to the time it took us to handle
+    // the last one.
+    //
+    // Notice the use of TimeInMicro() instead of Time() to avoid overflow in
+    // long running programs.
+    if ( m_timeToBlockWheelEventsUntil <= m_stopWatch.TimeInMicro() )
     {
-        m_lastWheelTimestamp = m_stopWatch.Time();
+        const wxLongLong beforeMouseWheel = m_stopWatch.TimeInMicro();
         m_swx->DoMouseWheel(evt.GetWheelRotation(),
                             evt.GetWheelDelta(),
                             evt.GetLinesPerAction(),
                             evt.ControlDown(),
                             evt.IsPageScroll());
-        m_lastWheelTimestamp = m_stopWatch.Time() - m_lastWheelTimestamp;
-        m_lastWheelTimestamp += evt.GetTimestamp();
+        const wxLongLong afterMouseWheel = m_stopWatch.TimeInMicro();
+        m_timeToBlockWheelEventsUntil = afterMouseWheel;
+        m_timeToBlockWheelEventsUntil += afterMouseWheel - beforeMouseWheel;
     }
 }
 
diff --git a/src/stc/stc.cpp.in b/src/stc/stc.cpp.in
index 2dfa4ec02a..ec2e890e47 100644
--- a/src/stc/stc.cpp.in
+++ b/src/stc/stc.cpp.in
@@ -199,7 +199,7 @@ bool wxStyledTextCtrl::Create(wxWindow *parent,
     m_swx = new ScintillaWX(this);
     m_stopWatch.Start();
     m_lastKeyDownConsumed = false;
-    m_lastWheelTimestamp = 0;
+    m_timeToBlockWheelEventsUntil = 0;
     m_vScrollBar = NULL;
     m_hScrollBar = NULL;
 #if wxUSE_UNICODE
@@ -764,18 +764,24 @@ void wxStyledTextCtrl::OnContextMenu(wxContextMenuEvent& evt) {
 
 void wxStyledTextCtrl::OnMouseWheel(wxMouseEvent& evt)
 {
-    // prevent having an event queue with wheel events that cannot be processed
-    // reasonably fast (see ticket #9057)
-    if ( m_lastWheelTimestamp <= evt.GetTimestamp() )
+    // Prevent having an event queue with wheel events that cannot be processed
+    // reasonably fast (see ticket #9057) by ignoring all of them that happen
+    // during the time interval corresponding to the time it took us to handle
+    // the last one.
+    //
+    // Notice the use of TimeInMicro() instead of Time() to avoid overflow in
+    // long running programs.
+    if ( m_timeToBlockWheelEventsUntil <= m_stopWatch.TimeInMicro() )
     {
-        m_lastWheelTimestamp = m_stopWatch.Time();
+        const wxLongLong beforeMouseWheel = m_stopWatch.TimeInMicro();
         m_swx->DoMouseWheel(evt.GetWheelRotation(),
                             evt.GetWheelDelta(),
                             evt.GetLinesPerAction(),
                             evt.ControlDown(),
                             evt.IsPageScroll());
-        m_lastWheelTimestamp = m_stopWatch.Time() - m_lastWheelTimestamp;
-        m_lastWheelTimestamp += evt.GetTimestamp();
+        const wxLongLong afterMouseWheel = m_stopWatch.TimeInMicro();
+        m_timeToBlockWheelEventsUntil = afterMouseWheel;
+        m_timeToBlockWheelEventsUntil += afterMouseWheel - beforeMouseWheel;
     }
 }
 
diff --git a/src/stc/stc.h.in b/src/stc/stc.h.in
index 73fa5603c9..55e0501f78 100644
--- a/src/stc/stc.h.in
+++ b/src/stc/stc.h.in
@@ -490,9 +490,8 @@ protected:
 
     bool                m_lastKeyDownConsumed;
 
-    // the timestamp that consists of the last wheel event
-    // added to the time taken to process that event.
-    long m_lastWheelTimestamp;
+    // Time until when we should ignore any new mouse wheel events.
+    wxLongLong m_timeToBlockWheelEventsUntil;
 
     friend class ScintillaWX;
     friend class Platform;