Major clean up of MakeContextCurrent

Rearrange most of the internals of MakeContextCurrent.	Put all of the code to
bind the new context up front.	If that is successful, unbind the old context.
This saves a lot of code and removes some locking crazyiness.

This patch has been tested for indirect rendering with glxinfo, glxgears,
manywin, and wincopy.

1 files changed, 87 insertions, 151 deletions

diff --git a/src/glx/x11/glxext.c b/src/glx/x11/glxext.c
index ab2795e..7e9327b 100644
--- a/src/glx/x11/glxext.c
+++ b/src/glx/x11/glxext.c
@@ -1480,12 +1480,17 @@ static Bool SendMakeCurrentRequest( Display *dpy, CARD8 opcode,
  * \warning
  * This function assumes that \c dpy is locked with \c LockDisplay on entry.
  */
-static Bool SendMakeCurrentRequest( Display *dpy, CARD8 opcode,
-				    GLXContextID gc_id, GLXContextTag gc_tag,
-				    GLXDrawable draw, GLXDrawable read,
-				    xGLXMakeCurrentReply * reply )
+static Bool SendMakeCurrentRequest(Display *dpy, CARD8 opcode,
+				   GLXContextID gc_id, GLXContextTag gc_tag,
+				   GLXDrawable draw, GLXDrawable read,
+				   xGLXMakeCurrentReply *reply)
 {
-    if ( draw == read ) {
+    Bool ret;
+
+
+    LockDisplay(dpy);
+
+    if (draw == read) {
 	xGLXMakeCurrentReq *req;
 
 	GetReq(GLXMakeCurrent,req);
@@ -1503,7 +1508,7 @@ static Bool SendMakeCurrentRequest( Display *dpy, CARD8 opcode,
 	 * not the SGI extension.
 	 */
 
-	if ( (priv->majorVersion > 1) || (priv->minorVersion >= 3) ) {
+	if ((priv->majorVersion > 1) || (priv->minorVersion >= 3)) {
 	    xGLXMakeContextCurrentReq *req;
 
 	    GetReq(GLXMakeContextCurrent,req);
@@ -1531,7 +1536,12 @@ static Bool SendMakeCurrentRequest( Display *dpy, CARD8 opcode,
 	}
     }
 
-    return _XReply(dpy, (xReply*) reply, 0, False);
+    ret = _XReply(dpy, (xReply*) reply, 0, False);
+
+    UnlockDisplay(dpy);
+    SyncHandle();
+
+    return ret;
 }
 
 
@@ -1554,161 +1564,93 @@ static Bool UnbindContextWrapper( GLXContext gc )
 #endif /* GLX_DIRECT_RENDERING */
 
 
-/*
-** Make a particular context current.
-** NOTE: this is in this file so that it can access dummyContext.
-*/
+/**
+ * Make a particular context current.
+ * 
+ * \note This is in this file so that it can access dummyContext.
+ */
 USED static Bool MakeContextCurrent(Display *dpy, GLXDrawable draw,
                                     GLXDrawable read, GLXContext gc)
 {
     xGLXMakeCurrentReply reply;
-    GLXContext oldGC;
-    CARD8 opcode, oldOpcode;
-    Bool sentRequestToOldDpy = False;
-    Bool bindReturnValue = True;
+    const GLXContext oldGC = __glXGetCurrentContext();
+    const CARD8 opcode = __glXSetupForCommand(dpy);
+    const CARD8 oldOpcode = ((gc == oldGC) || (oldGC == &dummyContext))
+      ? opcode : __glXSetupForCommand(oldGC->currentDpy);
+    Bool bindReturnValue;
+
 
-    opcode = __glXSetupForCommand(dpy);
-    if (!opcode) {
+    if (!opcode || !oldOpcode) {
 	return GL_FALSE;
     }
 
-    /*
-    ** Make sure that the new context has a nonzero ID.  In the request,
-    ** a zero context ID is used only to mean that we bind to no current
-    ** context.
-    */
+    /* Make sure that the new context has a nonzero ID.  In the request,
+     * a zero context ID is used only to mean that we bind to no current
+     * context.
+     */
     if ((gc != NULL) && (gc->xid == None)) {
 	return GL_FALSE;
     }
 
-    oldGC = __glXGetCurrentContext();
-    oldOpcode = (gc == oldGC) ? opcode : __glXSetupForCommand(oldGC->currentDpy);
-    if (!oldOpcode) {
+#ifndef GLX_DIRECT_RENDERING
+    if (gc && gc->isDirect) {
 	return GL_FALSE;
     }
-
-    if ((dpy != oldGC->currentDpy || (gc && gc->isDirect)) &&
-	!oldGC->isDirect && oldGC != &dummyContext) {
-	/*
-	** We are either switching from one dpy to another and have to
-	** send a request to the previous dpy to unbind the previous
-	** context, or we are switching away from a indirect context to
-	** a direct context and have to send a request to the dpy to
-	** unbind the previous context.
-	*/
-	sentRequestToOldDpy = True;
-        LockDisplay(oldGC->currentDpy);
-	if ( ! SendMakeCurrentRequest( oldGC->currentDpy, oldOpcode, None,
-				       oldGC->currentContextTag, None, None,
-				       &reply ) ) {
-	    /* The make current failed.  Just return GL_FALSE. */
-	    UnlockDisplay(oldGC->currentDpy);
-	    SyncHandle();
-	    return GL_FALSE;
-	}
-
-	oldGC->currentContextTag = 0;
-    }
+#endif
 
     _glapi_check_multithread();
 
 #ifdef GLX_DIRECT_RENDERING
-    /* Unbind the old direct rendering context */
-    if (oldGC->isDirect) {
-	if (oldGC->driContext.private) {
-	    if (! UnbindContextWrapper( oldGC )) {
-		/* The make current failed.  Just return GL_FALSE. */
-		return GL_FALSE;
-	    }
-	}
-	oldGC->currentContextTag = 0;
-    }
-
     /* Bind the direct rendering context to the drawable */
     if (gc && gc->isDirect) {
-	if (gc->driContext.private) {
-	    bindReturnValue = BindContextWrapper( dpy, gc, draw, read );
-	}
-    } else {
+	bindReturnValue = (gc->driContext.private) 
+	  ? BindContextWrapper(dpy, gc, draw, read)
+	  : False;
+    } else
 #endif
+    {
 	/* Send a glXMakeCurrent request to bind the new context. */
-	LockDisplay(dpy);
-
-	bindReturnValue = SendMakeCurrentRequest( dpy, opcode, 
-						  gc ? gc->xid : None,
-						  oldGC->currentContextTag,
-						  draw, read, &reply );
-	UnlockDisplay(dpy);
-#ifdef GLX_DIRECT_RENDERING
+	bindReturnValue = 
+	  SendMakeCurrentRequest(dpy, opcode, gc ? gc->xid : None,
+				 (dpy != oldGC->currentDpy) 
+				 ? None : oldGC->currentContextTag,
+				 draw, read, &reply);
     }
-#endif
 
 
     if (!bindReturnValue) {
-	/* The make current failed. */
-	if (gc && !gc->isDirect) {
-	    SyncHandle();
-	}
+	return False;
+    }
+
+    if ((dpy != oldGC->currentDpy || (gc && gc->isDirect)) &&
+	!oldGC->isDirect && oldGC != &dummyContext) {
+	xGLXMakeCurrentReply dummy_reply;
 
+	/* We are either switching from one dpy to another and have to
+	 * send a request to the previous dpy to unbind the previous
+	 * context, or we are switching away from a indirect context to
+	 * a direct context and have to send a request to the dpy to
+	 * unbind the previous context.
+	 */
+	(void) SendMakeCurrentRequest(oldGC->currentDpy, oldOpcode, None,
+				      oldGC->currentContextTag, None, None,
+				      & dummy_reply);
+    }
 #ifdef GLX_DIRECT_RENDERING
-	/* If the old context was direct rendering, then re-bind to it. */
-	if (oldGC->isDirect) {
-	    if (oldGC->driContext.private) {
-		if (! BindContextWrapper( oldGC->currentDpy, oldGC,
-					  oldGC->currentDrawable,
-					  oldGC->currentReadable )) {
-		    /*
-		    ** The request failed; this cannot happen with the
-		    ** current API.  If in the future the API is
-		    ** extended to allow context sharing between
-		    ** clients, then this may fail (because another
-		    ** client may have grabbed the context); in that
-		    ** case, we cannot undo the previous request, and
-		    ** cannot adhere to the "no-op" behavior.
-		    */
-		}
-	    }
-	} else
-#endif
-	/*
-	** If we had just sent a request to a previous dpy, we have to
-	** undo that request (because if a command fails, it should act
-	** like a no-op) by making current to the previous context and
-	** drawable.
-	*/
-	if (sentRequestToOldDpy) {
-	    if ( !SendMakeCurrentRequest( oldGC->currentDpy, oldOpcode,
-					  oldGC->xid, 0, 
-					  oldGC->currentDrawable,
-					  oldGC->currentReadable, &reply ) ) {
-		UnlockDisplay(oldGC->currentDpy);
-		SyncHandle();
-		/*
-		** The request failed; this cannot happen with the
-		** current API.  If in the future the API is extended to
-		** allow context sharing between clients, then this may
-		** fail (because another client may have grabbed the
-		** context); in that case, we cannot undo the previous
-		** request, and cannot adhere to the "no-op" behavior.
-		*/
-	    }
-            else {
-		UnlockDisplay(oldGC->currentDpy);
-            }
-	    oldGC->currentContextTag = reply.contextTag;
-	}
-	return GL_FALSE;
+    else if (oldGC->isDirect && oldGC->driContext.private) {
+	(void) UnbindContextWrapper(oldGC);
     }
+#endif
+
 
     /* Update our notion of what is current */
     __glXLock();
     if (gc == oldGC) {
-	/*
-	** Even though the contexts are the same the drawable might have
-	** changed.  Note that gc cannot be the dummy, and that oldGC
-	** cannot be NULL, therefore if they are the same, gc is not
-	** NULL and not the dummy.
-	*/
+	/* Even though the contexts are the same the drawable might have
+	 * changed.  Note that gc cannot be the dummy, and that oldGC
+	 * cannot be NULL, therefore if they are the same, gc is not
+	 * NULL and not the dummy.
+	 */
 	gc->currentDrawable = draw;
 	gc->currentReadable = read;
     } else {
@@ -1720,11 +1662,10 @@ USED static Bool MakeContextCurrent(Display *dpy, GLXDrawable draw,
 	    oldGC->currentContextTag = 0;
 
 	    if (oldGC->xid == None) {
-		/* 
-		** We are switching away from a context that was
-		** previously destroyed, so we need to free the memory
-		** for the old handle.
-		*/
+		/* We are switching away from a context that was
+		 * previously destroyed, so we need to free the memory
+		 * for the old handle.
+		 */
 #ifdef GLX_DIRECT_RENDERING
 		/* Destroy the old direct rendering context */
 		if (oldGC->isDirect) {
@@ -1740,35 +1681,30 @@ USED static Bool MakeContextCurrent(Display *dpy, GLXDrawable draw,
 	}
 	if (gc) {
 	    __glXSetCurrentContext(gc);
-#ifdef GLX_DIRECT_RENDERING
+
+	    gc->currentDpy = dpy;
+	    gc->currentDrawable = draw;
+	    gc->currentReadable = read;
+
             if (!gc->isDirect) {
                if (!IndirectAPI)
                   IndirectAPI = __glXNewIndirectAPI();
                _glapi_set_dispatch(IndirectAPI);
-# ifdef GLX_USE_APPLEGL
+
+#ifdef GLX_USE_APPLEGL
                do {
                    extern void XAppleDRIUseIndirectDispatch(void);
                    XAppleDRIUseIndirectDispatch();
                } while (0);
-# endif
-            }
-#else
-            /* if not direct rendering, always need indirect dispatch */
-            if (!IndirectAPI)
-               IndirectAPI = __glXNewIndirectAPI();
-            _glapi_set_dispatch(IndirectAPI);
 #endif
-	    gc->currentDpy = dpy;
-	    gc->currentDrawable = draw;
-	    gc->currentReadable = read;
 
-	    if ( ! gc->isDirect ) {
-		__GLXattribute * state = (__GLXattribute *)(gc->client_state_private);
+		__GLXattribute *state = 
+		  (__GLXattribute *)(gc->client_state_private);
 
 		gc->currentContextTag = reply.contextTag;
-		if ( state->array_state == NULL ) {
-		    (void) glGetString( GL_EXTENSIONS );
-		    (void) glGetString( GL_VERSION );
+		if (state->array_state == NULL) {
+		    (void) glGetString(GL_EXTENSIONS);
+		    (void) glGetString(GL_VERSION);
 		    __glXInitVertexArrayState(gc);
 		}
 	    }