mi: Add a default no-op miSourceValidate

Slightly simplifies the callers since they don't need to check for
non-NULL anymore.

I do extremely hate the workarounds here to suppress misprite taking the
cursor down though. Surely there's a better way.

[1.20: Do not in fact simplify the callers as above, since it would
change the ABI. - ajax]

Reviewed-by: Michel Dänzer <mdaenzer@redhat.com>
(cherry picked from commit ff310903f3)

dix/pixmap.c

@@ -32,6 +32,7 @@ from The Open Group.
 
 #include <X11/X.h>
 #include "scrnintstr.h"
+#include "mi.h"
 #include "misc.h"
 #include "os.h"
 #include "windowstr.h"
@@ -395,7 +396,7 @@ Bool PixmapSyncDirtyHelper(PixmapDirtyUpdatePtr dirty)
      * leaves the software cursor in place
      */
     SourceValidate = pScreen->SourceValidate;
-    pScreen->SourceValidate = NULL;
+    pScreen->SourceValidate = miSourceValidate;
 
     RegionTranslate(&pixregion, dirty->x, dirty->y);
     RegionIntersect(&pixregion, &pixregion, region);

doc/Xserver-spec.xml

@@ -2930,8 +2930,8 @@ The sample server implementation is in Xserver/fb/fbscreen.c.</para>
 		unsigned int subWindowMode;
 
 </programlisting></blockquote>
-SourceValidate should be called by CopyArea/CopyPlane primitives when
+SourceValidate should be called by any primitive that reads from pDrawable.
-the SourceValidate function pointer in the screen is non-null.  If you know that
+If you know that
 you will never need SourceValidate, you can avoid this check.  Currently,
 SourceValidate is used by the mi software cursor code to remove the cursor
 from the screen when the source rectangle overlaps the cursor position.

hw/xfree86/modes/xf86Rotate.c

@@ -28,7 +28,7 @@
 #include <stddef.h>
 #include <string.h>
 #include <stdio.h>
-
+#include "mi.h"
 #include "xf86.h"
 #include "xf86DDC.h"
 #include "windowstr.h"
@@ -191,7 +191,7 @@ xf86RotateRedisplay(ScreenPtr pScreen)
          * leaves the software cursor in place
          */
         SourceValidate = pScreen->SourceValidate;
-        pScreen->SourceValidate = NULL;
+        pScreen->SourceValidate = miSourceValidate;
 
         for (c = 0; c < xf86_config->num_crtc; c++) {
             xf86CrtcPtr crtc = xf86_config->crtc[c];

hw/xnest/Screen.c

@@ -263,7 +263,6 @@ xnestOpenScreen(ScreenPtr pScreen, int argc, char *argv[])
     pScreen->SaveScreen = xnestSaveScreen;
     pScreen->GetImage = xnestGetImage;
     pScreen->GetSpans = xnestGetSpans;
-    pScreen->SourceValidate = NULL;
 
     /* Window Procedures */
 

mi/mi.h

@@ -360,6 +360,10 @@ extern _X_EXPORT void miPushPixels(GCPtr /*pGC */ ,
 
 /* miscrinit.c */
 
+extern _X_EXPORT void
+miSourceValidate(DrawablePtr pDrawable, int x, int y, int w, int h,
+                 unsigned int subWindowMode);
+
 extern _X_EXPORT Bool miModifyPixmapHeader(PixmapPtr pPixmap,
                                            int width,
                                            int height,

mi/miscrinit.c

@@ -124,6 +124,12 @@ miCloseScreen(ScreenPtr pScreen)
     return ((*pScreen->DestroyPixmap) ((PixmapPtr) pScreen->devPrivate));
 }
 
+void
+miSourceValidate(DrawablePtr pDrawable, int x, int y, int w, int h,
+                 unsigned int subWindowMode)
+{
+}
+
 /* With the introduction of pixmap privates, the "screen pixmap" can no
  * longer be created in miScreenInit, since all the modules that could
  * possibly ask for pixmap private space have not been initialized at
@@ -243,7 +249,7 @@ miScreenInit(ScreenPtr pScreen, void *pbits,  /* pointer to screen bits */
     }
     /* else CloseScreen */
     /* QueryBestSize, SaveScreen, GetImage, GetSpans */
-    pScreen->SourceValidate = (SourceValidateProcPtr) 0;
+    pScreen->SourceValidate = miSourceValidate;
     /* CreateWindow, DestroyWindow, PositionWindow, ChangeWindowAttributes */
     /* RealizeWindow, UnrealizeWindow */
     pScreen->ValidateTree = miValidateTree;