src/yajl_tree.c: errors during parsing leave incomplete data structures

- so don't pass possible NULL pointers to YA_FREE()!

(maybe this should be fixed so incomplete data structures are never
returned in the first place, but on the other hand allocating and
filling empty values could lead to even more mistaken assumptions)

src/yajl_tree.c

@@ -100,7 +100,7 @@ static void yajl_object_free (yajl_val v)
 # endif
         YA_FREE(yajl_tree_parse_afs, __UNCONST(v->u.object.keys[i]));
         v->u.object.keys[i] = NULL;
-        yajl_tree_free (v->u.object.values[i]);
+        yajl_tree_free(v->u.object.values[i]);
         v->u.object.values[i] = NULL;
     }
 
@@ -118,14 +118,17 @@ static void yajl_array_free (yajl_val v)
     size_t i;
 
     assert(YAJL_IS_ARRAY(v));
+    assert(v->u.array.len == 0 ? (v->u.array.values == NULL)
+                               : (v->u.array.values != NULL));
 
-    for (i = 0; i < v->u.array.len; i++)
-    {
-        yajl_tree_free (v->u.array.values[i]);
+    for (i = 0; i < v->u.array.len; i++) {
+        yajl_tree_free(v->u.array.values[i]);
         v->u.array.values[i] = NULL;
     }
 
-    YA_FREE(yajl_tree_parse_afs, v->u.array.values);
+    if (v->u.array.values != NULL) {
+        YA_FREE(yajl_tree_parse_afs, v->u.array.values);
+    }
     YA_FREE(yajl_tree_parse_afs, v);
 }
 
@@ -340,7 +343,7 @@ static int handle_number (void *ctx, const char *string, size_t string_length)
     endptr = NULL;
     errno = 0;
     v->u.number.d = strtod(v->u.number.r, &endptr);
-    if ((errno == 0) && (endptr != NULL) && (*endptr == 0))
+    if ((errno == 0) && (endptr != NULL) && (*endptr == 0)) /* XXX endptr != v->u.number.r */
         v->u.number.flags |= YAJL_NUMBER_DOUBLE_VALID;
 
     return ((context_add_value(ctx, v) == 0) ? STATUS_CONTINUE : STATUS_ABORT);
@@ -558,28 +561,25 @@ void yajl_tree_free (yajl_val v)        /*+ Pointer to a JSON value returned by
                                          * "yajl_tree_parse".  Passing NULL is
                                          * valid and results in a no-op. +*/
 {
-    if (v == NULL) return;
+    if (v == NULL) {
+        return;
+    }
 
-    if (YAJL_IS_STRING(v))
-    {
-        YA_FREE(yajl_tree_parse_afs, v->u.string);
+    if (YAJL_IS_STRING(v)) {
+        if (v->u.string != NULL) {
+            YA_FREE(yajl_tree_parse_afs, v->u.string);
+        }
         YA_FREE(yajl_tree_parse_afs, v);
-    }
-    else if (YAJL_IS_NUMBER(v))
-    {
-        YA_FREE(yajl_tree_parse_afs, v->u.number.r);
+    } else if (YAJL_IS_NUMBER(v)) {
+        if (v->u.number.r != NULL) {
+            YA_FREE(yajl_tree_parse_afs, v->u.number.r);
+        }
         YA_FREE(yajl_tree_parse_afs, v);
-    }
-    else if (YAJL_IS_OBJECT(v))
-    {
+    } else if (YAJL_IS_OBJECT(v)) {
         yajl_object_free(v);
-    }
-    else if (YAJL_IS_ARRAY(v))
-    {
+    } else if (YAJL_IS_ARRAY(v)) {
         yajl_array_free(v);
-    }
-    else /* if (yajl_t_true or yajl_t_false or yajl_t_null) */
-    {
+    } else /* if (yajl_t_true or yajl_t_false or yajl_t_null) */ {
         YA_FREE(yajl_tree_parse_afs, v);
     }
 }