Xi: use calloc() instead of malloc()

Using calloc() instead of malloc() as preventive measure, so there
never can be any hidden bugs or leaks due uninitialized memory.

The extra cost of using this compiler intrinsic should be practically
impossible to measure - in many cases a good compiler can even deduce
if certain areas really don't need to be zero'd (because they're written
to right after allocation) and create more efficient machine code.

The code pathes in question are pretty cold anyways, so it's probably
not worth even thinking about potential extra runtime costs.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>

Xi/exevents.c

@@ -2335,12 +2335,10 @@ DeliverGestureEventToOwner(DeviceIntPtr dev, GestureInfoPtr gi, InternalEvent *e
 int
 InitProximityClassDeviceStruct(DeviceIntPtr dev)
 {
-    ProximityClassPtr proxc;
-
     BUG_RETURN_VAL(dev == NULL, FALSE);
     BUG_RETURN_VAL(dev->proximity != NULL, FALSE);
 
-    proxc = (ProximityClassPtr) malloc(sizeof(ProximityClassRec));
+    ProximityClassPtr proxc = calloc(1, sizeof(ProximityClassRec));
     if (!proxc)
         return FALSE;
     proxc->sourceid = dev->id;

Xi/getdctl.c

@@ -168,7 +168,7 @@ int
 ProcXGetDeviceControl(ClientPtr client)
 {
     int rc, total_length = 0;
-    char *buf, *savbuf;
+    char *savbuf;
     DeviceIntPtr dev;
     xGetDeviceControlReply rep;
 
@@ -206,7 +206,7 @@ ProcXGetDeviceControl(ClientPtr client)
         return BadValue;
     }
 
-    buf = (char *) malloc(total_length);
+    char *buf = calloc(1, total_length);
     if (!buf)
         return BadAlloc;
     savbuf = buf;

Xi/getfctl.c

@@ -261,7 +261,7 @@ int
 ProcXGetFeedbackControl(ClientPtr client)
 {
     int rc, total_length = 0;
-    char *buf, *savbuf;
+    char *savbuf;
     DeviceIntPtr dev;
     KbdFeedbackPtr k;
     PtrFeedbackPtr p;
@@ -315,7 +315,7 @@ ProcXGetFeedbackControl(ClientPtr client)
     if (total_length == 0)
         return BadMatch;
 
-    buf = (char *) malloc(total_length);
+    char *buf = (char *) calloc(1, total_length);
     if (!buf)
         return BadAlloc;
     savbuf = buf;

Xi/getselev.c

@@ -131,7 +131,7 @@ ProcXGetSelectedExtensionEvents(ClientPtr client)
         total_length = (rep.all_clients_count + rep.this_client_count) *
             sizeof(XEventClass);
         rep.length = bytes_to_int32(total_length);
-        buf = (XEventClass *) malloc(total_length);
+        buf = calloc(1, total_length);
 
         tclient = buf;
         aclient = buf + rep.this_client_count;

Xi/xibarriers.c

@@ -103,9 +103,7 @@ typedef struct _BarrierScreen {
 
 static struct PointerBarrierDevice *AllocBarrierDevice(void)
 {
-    struct PointerBarrierDevice *pbd = NULL;
+    struct PointerBarrierDevice *pbd = calloc(1, sizeof(struct PointerBarrierDevice));
-
-    pbd = malloc(sizeof(struct PointerBarrierDevice));
     if (!pbd)
         return NULL;
 
@@ -558,15 +556,13 @@ CreatePointerBarrierClient(ClientPtr client,
     ScreenPtr screen;
     BarrierScreenPtr cs;
     int err;
-    int size;
     int i;
-    struct PointerBarrierClient *ret;
     CARD16 *in_devices;
     DeviceIntPtr dev;
 
-    size = sizeof(*ret) + sizeof(DeviceIntPtr) * stuff->num_devices;
+    const int size = sizeof(struct PointerBarrierClient)
-    ret = malloc(size);
+                   + sizeof(DeviceIntPtr) * stuff->num_devices;
-
+    struct PointerBarrierClient *ret = calloc(1, size);
     if (!ret) {
         return BadAlloc;
     }

Xi/xiproperty.c

@@ -575,9 +575,7 @@ XIUnregisterPropertyHandler(DeviceIntPtr dev, long id)
 static XIPropertyPtr
 XICreateDeviceProperty(Atom property)
 {
-    XIPropertyPtr prop;
+    XIPropertyPtr prop = calloc(1, sizeof(XIPropertyRec));
-
-    prop = (XIPropertyPtr) malloc(sizeof(XIPropertyRec));
     if (!prop)
         return NULL;