Xi: add versioning support.

Remember the version the client sent to us, so we can adjust our replies
accordingly. This requires the client to use the {major|minor}Version fields
in the GetExtensionVersion request. However, they were padding before, so we
must assume they are garbage if nbytes is non-zero. If nbytes is zero, the
client is probably a new client and we can handle it correctly.

Xi/exglobals.h

@@ -31,6 +31,7 @@ OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 #ifdef HAVE_DIX_CONFIG_H
 #include <dix-config.h>
 #endif
+#include "privates.h"
 
 #ifndef EXGLOBALS_H
 #define EXGLOBALS_H 1
@@ -75,4 +76,5 @@ extern int DeviceLeaveNotify;
 
 extern int RT_INPUTCLIENT;
 
+extern DevPrivateKey XIClientPrivateKey;
 #endif /* EXGLOBALS_H */

Xi/extinit.c

@@ -72,6 +72,7 @@ SOFTWARE.
 #include "exglobals.h"
 #include "swaprep.h"
 #include "registry.h"
+#include "privates.h"
 
 /* modules local to Xi */
 #include "allowev.h"
@@ -324,19 +325,42 @@ int RT_INPUTCLIENT;
 
 extern XExtensionVersion AllExtensionVersions[];
 
+
 Mask PropagateMask[MAX_DEVICES];
 
+/*****************************************************************
+ *
+ * Versioning support
+ *
+ */
+
+DevPrivateKey XIClientPrivateKey = &XIClientPrivateKey;
+
+static XExtensionVersion thisversion = { XI_Present,
+    XI_2_Major,
+    XI_2_Minor
+};
+
+
 /*****************************************************************
  *
  * Declarations of local routines.
  *
  */
 
-static XExtensionVersion thisversion = { XI_Present,
-    XI_2_Major,
-    XI_2_Minor
-};
+static void
+XIClientCallback(CallbackListPtr        *list,
+                 pointer                closure,
+                 pointer                data)
+{
+    NewClientInfoRec *clientinfo = (NewClientInfoRec*)data;
+    ClientPtr pClient = clientinfo->client;
+    XIClientPtr pXIClient;
 
+    pXIClient = dixLookupPrivate(&pClient->devPrivates, XIClientPrivateKey);
+    pXIClient->major_version = 0;
+    pXIClient->minor_version = 0;
+}
 
 /*************************************************************************
  *
@@ -1080,6 +1104,7 @@ XIGEEventFill(xGenericEvent* ev, DeviceIntPtr pDev,
  *
  * This extension has several events and errors.
  *
+ * XI is mandatory nowadays, so if we fail to init XI, we die.
  */
 
 void
@@ -1087,6 +1112,12 @@ XInputExtensionInit(void)
 {
     ExtensionEntry *extEntry;
 
+    if (!dixRequestPrivate(XIClientPrivateKey, sizeof(XIClientRec)))
+        FatalError("Cannot request private for XI.\n");
+
+    if (!AddCallback(&ClientStateCallback, XIClientCallback, 0))
+        FatalError("Failed to add callback to XI.\n");
+
     extEntry = AddExtension(INAME, IEVENTS, IERRORS, ProcIDispatch,
 			    SProcIDispatch, IResetProc, StandardMinorOpcode);
     if (extEntry) {

Xi/getvers.c

@@ -59,6 +59,7 @@ SOFTWARE.
 #include "inputstr.h"	/* DeviceIntPtr      */
 #include <X11/extensions/XI.h>
 #include <X11/extensions/XIproto.h>
+#include "exevents.h"
 #include "exglobals.h"
 
 #include "getvers.h"
@@ -93,6 +94,7 @@ int
 ProcXGetExtensionVersion(ClientPtr client)
 {
     xGetExtensionVersionReply rep;
+    XIClientPtr pXIClient;
 
     REQUEST(xGetExtensionVersionReq);
     REQUEST_AT_LEAST_SIZE(xGetExtensionVersionReq);
@@ -101,6 +103,21 @@ ProcXGetExtensionVersion(ClientPtr client)
 			  stuff->nbytes + 3) >> 2)
 	return BadLength;
 
+    pXIClient = dixLookupPrivate(&client->devPrivates, XIClientPrivateKey);
+
+    /* GetExtensionVersionReq before XI 2 didn't supply the client's
+     * major/minor. So we don't actually have a clue what they support.
+     * {major|minor}Version was added as part of XI, so if they are set, we
+     * know we can trust it. In this case the client must set nbytes to 0
+     * though, otherwise we have to assume that the version are padding
+     * garbage.
+     */
+    if (!stuff->nbytes) /* Client using XQueryInputVersion(). */
+    {
+        pXIClient->major_version = stuff->majorVersion;
+        pXIClient->minor_version = stuff->minorVersion;
+    } /* else version unknown, leave it at 0.0 */
+
     rep.repType = X_Reply;
     rep.RepType = X_GetExtensionVersion;
     rep.length = 0;

include/exevents.h

@@ -32,6 +32,15 @@ OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 
 #include <X11/extensions/XIproto.h>
 
+/**
+ * Attached to the devPrivates of each client. Specifies the version number as
+ * supported by the client.
+ */
+typedef struct _XIClientRec {
+        int major_version;
+        int minor_version;
+} XIClientRec, *XIClientPtr;
+
 extern void RegisterOtherDevice (
 	DeviceIntPtr           /* device */);