dix: add dixPropertyCreate()

This function shall be used for creating an entirely new property
structure from given data.

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

dix/property.c

@@ -325,11 +325,9 @@ dixChangeWindowProperty(ClientPtr pClient, WindowPtr pWin, Atom property,
 {
     PropertyPtr pProp;
     PropertyRec savedProp;
-    int sizeInBytes, totalSize, rc;
+    int rc;
     Mask access_mode;
 
-    sizeInBytes = format >> 3;
-    totalSize = len * sizeInBytes;
     access_mode = (mode == PropModeReplace) ? DixWriteAccess : DixBlendAccess;
 
     /* first see if property already exists */
@@ -338,20 +336,11 @@ dixChangeWindowProperty(ClientPtr pClient, WindowPtr pWin, Atom property,
     if (rc == BadMatch) {       /* just add to list */
         if (!MakeWindowOptional(pWin))
             return BadAlloc;
-        pProp = dixAllocateObjectWithPrivates(PropertyRec, PRIVATE_PROPERTY);
+
+        pProp = dixPropertyCreate(type, property, format, len, value);
         if (!pProp)
             return BadAlloc;
-        if (totalSize) {
-            if (!(pProp->data = calloc(1, totalSize))) {
-                dixPropertyFree(pProp);
-                return BadAlloc;
-            }
-            memcpy(pProp->data, value, totalSize);
-        }
-        pProp->propertyName = property;
-        pProp->type = type;
-        pProp->format = format;
-        pProp->size = len;
+
         rc = XaceHookPropertyAccess(pClient, pWin, &pProp,
                                     DixCreateAccess | DixWriteAccess);
         if (rc != Success) {
@@ -363,6 +352,9 @@ dixChangeWindowProperty(ClientPtr pClient, WindowPtr pWin, Atom property,
         pWin->properties = pProp;
     }
     else if (rc == Success) {
+        const int sizeInBytes = format >> 3;
+        const int totalSize = len * sizeInBytes;
+
         /* To append or prepend to a property the request format and type
            must match those of the already defined property.  The
            existing format and type are irrelevant when using the mode

dix/property_list.c

@@ -15,3 +15,29 @@ void dixPropertyFree(PropertyPtr pr)
         dixFreeObjectWithPrivates(pr, PRIVATE_PROPERTY);
     }
 }
+
+PropertyPtr dixPropertyCreate(Atom type, Atom name, int format, size_t len,
+                              const void *value)
+{
+    const int totalSize = (format >> 3) * len;
+
+    void *data = calloc(1, totalSize);
+    if (!data)
+        return NULL;
+
+    PropertyPtr pProp = dixAllocateObjectWithPrivates(PropertyRec, PRIVATE_PROPERTY);
+    if (!pProp) {
+        free(data);
+        return NULL;
+    }
+
+    memcpy(data, value, totalSize);
+
+    pProp->data = data;
+    pProp->propertyName = name;
+    pProp->format = format;
+    pProp->size = len;
+    pProp->type = type;
+
+    return pProp;
+}

dix/property_priv.h

@@ -109,4 +109,18 @@ void DeleteAllWindowProperties(WindowPtr pWin);
  */
 void dixPropertyFree(PropertyPtr pProp);
 
+/*
+ * Create and fill a new property structure from given data. The `value`
+ * is malloc()ed and copied over.
+ *
+ * @param type   AtomID of the property type
+ * @param name   AtomID of the property name
+ * @param format the property format (8/16/32 bits)
+ * @param len    length in units defined by format
+ * @param value  pointer to the (raw) property data)
+ * @return pointer to newly created property structure (NULL on allocation failure)
+ */
+PropertyPtr dixPropertyCreate(Atom type, Atom name, int format,
+                              size_t len, const void *value);
+
 #endif /* _XSERVER_PROPERTY_PRIV_H */