Implement core protocol backing store exclusively in terms of Composite.

Composite's automatic redirection is a more general mechanism than the
ad-hoc BS machinery, so it's much prettier to implement the one in terms
of the other.  Composite now wraps ChangeWindowAttributes and activates
automatic redirection for windows with backing store requested.  The old
backing store infrastructure is completely gutted: ABI-visible structures
retain the function pointers, but they never get called, and all the
open-coded conditionals throughout the DIX layer to implement BS are gone.

Note that this is still not a strictly complete implementation of backing
store, since Composite will throw the bits away on unmap and therefore
WhenMapped and Always hints are equivalent.

1 files changed, 0 insertions, 16 deletions

diff --git a/Xext/mbufbf.c b/Xext/mbufbf.c
index 04fc487d8..e29c974a3 100644
--- a/Xext/mbufbf.c
+++ b/Xext/mbufbf.c
@@ -329,10 +329,6 @@ bufCreateBuffer(pScreen, pWin, bufferNum)
     pBuffer->firstChild = NULL;
     pBuffer->lastChild  = NULL;
 
-    /* XXX - Worry about backingstore later */
-    pBuffer->backStorage   = NULL;
-    pBuffer->backingStore  = NotUseful;
-
     /* XXX - Need to call pScreen->CreateWindow for tile/stipples
      *       or should I just copy the devPrivates?
      */
@@ -505,18 +501,6 @@ bufClearImageBufferArea(pMBBuffer, x,y, w,h, generateExposures)
 
     pScreen = pBuffer->drawable.pScreen;
     REGION_INIT(pScreen, &reg, &box, 1);
-    if (pBuffer->backStorage)
-    {
-	/*
-	 * If the window has backing-store on, call through the
-	 * ClearToBackground vector to handle the special semantics
-	 * (i.e. things backing store is to be cleared out and
-	 * an Expose event is to be generated for those areas in backing
-	 * store if generateExposures is TRUE).
-	 */
-	pBSReg = (* pScreen->ClearBackingStore)(pBuffer, x, y, w, h,
-						 generateExposures);
-    }
 
     REGION_INTERSECT(pScreen, &reg, &reg, &pBuffer->clipList);
     if (pBuffer->backgroundState != None)