WIN cleanup paint message handling

Makes PAINT handling function use the POSTPAINT handling
function and unifies the locking behaviour, so we now check
the frame before trying to aquire the lock in both functions.

Change-Id: Ia6bac6e24d95e680830c5405f0ab34cbed6e9688

1 files changed, 68 insertions, 66 deletions

diff --git a/vcl/win/window/salframe.cxx b/vcl/win/window/salframe.cxx
index 06a7ce307bd2..f7b2afebc7fe 100644
--- a/vcl/win/window/salframe.cxx
+++ b/vcl/win/window/salframe.cxx
@@ -3692,93 +3692,96 @@ long ImplHandleSalObjSysCharMsg( HWND hWnd, WPARAM wParam, LPARAM lParam )
     return nRet;
 }
 
-static bool ImplHandlePaintMsg( HWND hWnd )
+enum class PostPaint
 {
-    bool bMutex = FALSE;
-    if ( ImplSalYieldMutexTryToAcquire() )
-        bMutex = TRUE;
+    IsPosted,
+    IsInitial
+};
 
-    // if we don't get the mutex, we can also change the clip region,
-    // because other threads doesn't use the mutex from the main
-    // thread --> see AcquireGraphics()
+static bool ImplHandlePostPaintMsg( HWND hWnd, RECT* pRect,
+                                    PostPaint eProcessed = PostPaint::IsPosted )
+{
+    bool bGotMutex = false;
 
     WinSalFrame* pFrame = GetWindowPtr( hWnd );
     if ( pFrame )
     {
-        // clip-region must be reset, as we do not get a proper
-        // bounding-rectangle otherwise
-        if ( pFrame->mpGraphics && pFrame->mpGraphics->getRegion() )
-            SelectClipRgn( pFrame->mpGraphics->getHDC(), nullptr );
+        if ( ImplSalYieldMutexTryToAcquire() )
+            bGotMutex = true;
 
-        // according to Window-Documentation one shall check first if
-        // there really is a paint-region
-        if ( GetUpdateRect( hWnd, nullptr, FALSE ) )
+        if ( bGotMutex )
         {
-            // Call BeginPaint/EndPaint to query the rect and send
-            // this Notification to rect
-            RECT aUpdateRect;
-            PAINTSTRUCT aPs;
-            BeginPaint( hWnd, &aPs );
-            CopyRect( &aUpdateRect, &aPs.rcPaint );
-
-            // Paint
-            // reset ClipRegion
-            if ( pFrame->mpGraphics && pFrame->mpGraphics->getRegion() )
-            {
-                SelectClipRgn( pFrame->mpGraphics->getHDC(),
-                               pFrame->mpGraphics->getRegion() );
-            }
-
-            if ( bMutex )
-            {
-                SalPaintEvent aPEvt( aUpdateRect.left, aUpdateRect.top, aUpdateRect.right-aUpdateRect.left, aUpdateRect.bottom-aUpdateRect.top, pFrame->mbPresentation );
-                pFrame->CallCallback( SalEvent::Paint, &aPEvt );
-            }
-            else
-            {
-                RECT* pRect = new RECT;
-                CopyRect( pRect, &aUpdateRect );
-                BOOL const ret = PostMessageW(hWnd, SAL_MSG_POSTPAINT, reinterpret_cast<WPARAM>(pRect), 0);
-                SAL_WARN_IF(0 == ret, "vcl", "ERROR: PostMessage() failed!");
-            }
-            EndPaint( hWnd, &aPs );
+            SalPaintEvent aPEvt( pRect->left, pRect->top, pRect->right-pRect->left, pRect->bottom-pRect->top );
+            pFrame->CallCallback( SalEvent::Paint, &aPEvt );
+            ImplSalYieldMutexRelease();
+            if ( PostPaint::IsPosted == eProcessed )
+                delete pRect;
         }
         else
         {
-            // reset ClipRegion
-            if ( pFrame->mpGraphics && pFrame->mpGraphics->getRegion() )
+            RECT* pMsgRect;
+            if ( PostPaint::IsInitial == eProcessed )
             {
-                SelectClipRgn( pFrame->mpGraphics->getHDC(),
-                               pFrame->mpGraphics->getRegion() );
+                pMsgRect = new RECT;
+                CopyRect( pMsgRect, pRect );
             }
+            else
+                pMsgRect = pRect;
+            BOOL const ret = PostMessageW(hWnd, SAL_MSG_POSTPAINT, reinterpret_cast<WPARAM>(pMsgRect), 0);
+            SAL_WARN_IF(0 == ret, "vcl", "ERROR: PostMessage() failed!");
         }
     }
 
-    if ( bMutex )
-        ImplSalYieldMutexRelease();
-
-    return bMutex;
+    return bGotMutex;
 }
 
-static void ImplHandlePaintMsg2( HWND hWnd, RECT* pRect )
+static bool ImplHandlePaintMsg( HWND hWnd )
 {
-    // Paint
-    if ( ImplSalYieldMutexTryToAcquire() )
+    bool bPaintSuccessful = false;
+
+    // even without the Yield mutex, we can still change the clip region,
+    // because other threads don't use the Yield mutex
+    // --> see AcquireGraphics()
+
+    WinSalFrame* pFrame = GetWindowPtr( hWnd );
+    if ( pFrame )
     {
-        WinSalFrame* pFrame = GetWindowPtr( hWnd );
-        if ( pFrame )
+        // clip region must be set, as we don't get a proper
+        // bounding rectangle otherwise
+        bool bHasClipRegion = pFrame->mpGraphics && pFrame->mpGraphics->getRegion();
+        if ( bHasClipRegion )
+            SelectClipRgn( pFrame->mpGraphics->getHDC(), nullptr );
+
+        // according to Windows documentation one shall check first if
+        // there really is a paint-region
+        RECT aUpdateRect;
+        PAINTSTRUCT aPs;
+        bool bHasPaintRegion = GetUpdateRect( hWnd, nullptr, FALSE );
+        if ( bHasPaintRegion )
         {
-            SalPaintEvent aPEvt( pRect->left, pRect->top, pRect->right-pRect->left, pRect->bottom-pRect->top );
-            pFrame->CallCallback( SalEvent::Paint, &aPEvt );
+            // call BeginPaint/EndPaint to query the paint rect and use
+            // this infomation in the (deferred) paint
+            BeginPaint( hWnd, &aPs );
+            CopyRect( &aUpdateRect, &aPs.rcPaint );
         }
-        ImplSalYieldMutexRelease();
-        delete pRect;
-    }
-    else
-    {
-        BOOL const ret = PostMessageW(hWnd, SAL_MSG_POSTPAINT, reinterpret_cast<WPARAM>(pRect), 0);
-        SAL_WARN_IF(0 == ret, "vcl", "ERROR: PostMessage() failed!");
+
+        // reset clip region
+        if ( bHasClipRegion )
+            SelectClipRgn( pFrame->mpGraphics->getHDC(),
+                           pFrame->mpGraphics->getRegion() );
+
+        // try painting
+        if ( bHasPaintRegion )
+        {
+            bPaintSuccessful = ImplHandlePostPaintMsg( hWnd, &aUpdateRect,
+                                                       PostPaint::IsInitial );
+            EndPaint( hWnd, &aPs );
+        }
+        else // if there is nothing to paint, the paint is successful
+            bPaintSuccessful = true;
     }
+
+    return bPaintSuccessful;
 }
 
 static void SetMaximizedFrameGeometry( HWND hWnd, WinSalFrame* pFrame, RECT* pParentRect )
@@ -5632,8 +5635,7 @@ LRESULT CALLBACK SalFrameWndProc( HWND hWnd, UINT nMsg, WPARAM wParam, LPARAM lP
             rDef = FALSE;
             break;
         case SAL_MSG_POSTPAINT:
-            ImplHandlePaintMsg2( hWnd, reinterpret_cast<RECT*>(wParam) );
-            bCheckTimers = true;
+            bCheckTimers = ImplHandlePostPaintMsg( hWnd, reinterpret_cast<RECT*>(wParam) );
             rDef = FALSE;
             break;