[jimtabor] 66452: [NtUser] - Fix API GetDCEx tests! Dedicated to the great work by Timo Kreuzer. - This uncovered a loop flaw, witch passed on any DCE last accessed.

Author: jimtabor
Date: Wed Feb 25 13:25:57 2015
New Revision: 66452

URL: http://svn.reactos.org/svn/reactos?rev=66452&view=rev
Log:
[NtUser]
- Fix API GetDCEx tests! Dedicated to the great work by Timo Kreuzer.
- This uncovered a loop flaw, witch passed on any DCE last accessed.

Modified:
    trunk/reactos/win32ss/user/ntuser/windc.c

Modified: trunk/reactos/win32ss/user/ntuser/windc.c
URL:
http://svn.reactos.org/svn/reactos/trunk/reactos/win32ss/user/ntuser/windc.…
==============================================================================
--- trunk/reactos/win32ss/user/ntuser/windc.c	[iso-8859-1] (original)
+++ trunk/reactos/win32ss/user/ntuser/windc.c	[iso-8859-1] Wed Feb 25 13:25:57 2015
@@ -366,7 +366,7 @@
       Flags |= DCX_CACHE;
    }
 
-   if (Flags & (DCX_WINDOW | DCX_PARENTCLIP)) Flags |= DCX_CACHE;
+   if (Flags & DCX_PARENTCLIP) Flags |= DCX_CACHE;
 
    // When GetDC is called with hWnd nz, DCX_CACHE & _WINDOW are clear w _USESTYLE
set.
    if (Flags & DCX_USESTYLE)
@@ -488,6 +488,7 @@
                break;
             }
          }
+         Dce = NULL; // Loop issue?
       }
       KeLeaveCriticalRegion();
 
@@ -497,7 +498,7 @@
       {
          Dce = DceAllocDCE(NULL, DCE_CACHE_DC);
       }
-      if (!Dce) return NULL;
+      if (Dce == NULL) return NULL;
 
       Dce->hwndCurrent = (Wnd ? Wnd->head.h : NULL);
       Dce->pwndOrg = Dce->pwndClip = Wnd;
@@ -510,20 +511,31 @@
       {
           Dce = CONTAINING_RECORD(ListEntry, DCE, List);
           ListEntry = ListEntry->Flink;
-          // Check for Window handle than HDC match for CLASS.
-          if (Dce->hwndCurrent == Wnd->head.h)
+
+          // Skip Cache DCE entries.
+          if (!(Dce->DCXFlags & DCX_CACHE))
           {
-             bUpdateVisRgn = FALSE;
-             break;
+             // Check for Window handle than HDC match for CLASS.
+             if (Dce->hwndCurrent == Wnd->head.h)
+             {
+                bUpdateVisRgn = FALSE;
+                break;
+             }
+             else if (Dce->hDC == hDC) break;
           }
-          if (Dce->hDC == hDC) break;
+          Dce = NULL; // Loop issue?
       }
       KeLeaveCriticalRegion();
+
+      if (Dce == NULL)
+      {
+         return(NULL);
+      }
 
       if ( (Flags & (DCX_INTERSECTRGN|DCX_EXCLUDERGN)) &&
            (Dce->DCXFlags & (DCX_INTERSECTRGN|DCX_EXCLUDERGN)) )
       {
-          DceDeleteClipRgn(Dce);
+         DceDeleteClipRgn(Dce);
       }
    }
 // First time use hax, need to use DceAllocDCE during window display init.