fix issue #281

doc/apiref.rst

@@ -708,6 +708,24 @@ allowed in object keys.
 
    .. versionadded:: 2.3
 
+.. function:: int json_object_update_new(json_t *object, json_t *other)
+
+   Like :func:`json_object_update()`, but steals the reference to
+   *other*. This is useful when *other* is newly created and not used
+   after the call.
+
+.. function:: int json_object_update_existing_new(json_t *object, json_t *other)
+
+   Like :func:`json_object_update_new()`, but only the values of existing
+   keys are updated. No new keys are created. Returns 0 on success or
+   -1 on error.
+
+.. function:: int json_object_update_missing_new(json_t *object, json_t *other)
+
+   Like :func:`json_object_update_new()`, but only new keys are created.
+   The value of any existing key is not changed. Returns 0 on success
+   or -1 on error.
+
 .. function:: json_object_foreach(object, key, value)
 
    Iterate over every key-value pair of ``object``, running the block

src/jansson.h

@@ -242,6 +242,30 @@ int json_object_iter_set(json_t *object, void *iter, json_t *value)
     return json_object_iter_set_new(object, iter, json_incref(value));
 }
 
+static JSON_INLINE
+int json_object_update_new(json_t *object, json_t *other)
+{
+    int ret = json_object_update(object, other);
+    json_decref(other);
+    return ret;
+}
+
+static JSON_INLINE
+int json_object_update_existing_new(json_t *object, json_t *other)
+{
+    int ret = json_object_update_existing(object, other);
+    json_decref(other);
+    return ret;
+}
+
+static JSON_INLINE
+int json_object_update_missing_new(json_t *object, json_t *other)
+{
+    int ret = json_object_update_missing(object, other);
+    json_decref(other);
+    return ret;
+}
+
 size_t json_array_size(const json_t *array);
 json_t *json_array_get(const json_t *array, size_t index) JANSSON_ATTRS(warn_unused_result);
 int json_array_set_new(json_t *array, size_t index, json_t *value);

test/suites/api/test_object.c

@@ -133,6 +133,32 @@ static void test_update()
        json_object_get(object, "h") != nine)
         fail("update works incorrectly");
 
+    /* update_new check */
+    if(json_object_clear(object))
+        fail("clear failed");
+
+    if(json_object_set(object, "a", ten) ||
+       json_object_set(object, "b", ten) ||
+       json_object_set(object, "c", ten) ||
+       json_object_set(object, "d", ten) ||
+       json_object_set(object, "e", ten))
+        fail("unable to set value");
+
+    if(json_object_update_new(object, json_pack("{s:O, s:O, s:O}", "b", nine, "f", nine, "g", nine)))
+        fail("unable to update_new a nonempty object");
+
+    if(json_object_size(object) != 7)
+        fail("invalid size after update_new");
+
+    if(json_object_get(object, "a") != ten ||
+       json_object_get(object, "b") != nine ||
+       json_object_get(object, "c") != ten ||
+       json_object_get(object, "d") != ten ||
+       json_object_get(object, "e") != ten ||
+       json_object_get(object, "f") != nine ||
+       json_object_get(object, "g") != nine)
+        fail("update_new works incorrectly");
+
     json_decref(nine);
     json_decref(ten);
     json_decref(other);
@@ -186,6 +212,23 @@ static void test_conditional_updates()
 
     json_decref(object);
 
+    /* json_object_update_existing_new check */
+    object = json_pack("{sisi}", "foo", 1, "bar", 2);
+
+    if(json_object_update_existing_new(object, json_pack("{sisi}", "foo", 3, "baz", 4)))
+        fail("json_object_update_existing_new failed");
+
+    if(json_object_size(object) != 2)
+        fail("json_object_update_existing_new added new items");
+
+    if(json_integer_value(json_object_get(object, "foo")) != 3)
+        fail("json_object_update_existing_new failed to update existing key");
+
+    if(json_integer_value(json_object_get(object, "bar")) != 2)
+        fail("json_object_update_existing_new updated wrong key");
+
+    json_decref(object);
+
     object = json_pack("{sisi}", "foo", 1, "bar", 2);
 
     if(json_object_update_missing(object, other))
@@ -203,6 +246,26 @@ static void test_conditional_updates()
     if(json_integer_value(json_object_get(object, "baz")) != 4)
         fail("json_object_update_missing didn't add new items");
 
+    json_decref(object);
+
+    /* json_object_update_missing_new check */
+    object = json_pack("{sisi}", "foo", 1, "bar", 2);
+
+    if(json_object_update_missing_new(object, json_pack("{sisi}", "foo", 3, "baz", 4)))
+        fail("json_object_update_missing_new failed");
+
+    if(json_object_size(object) != 3)
+        fail("json_object_update_missing_new didn't add new items");
+
+    if(json_integer_value(json_object_get(object, "foo")) != 1)
+        fail("json_object_update_missing_new updated existing key");
+
+    if(json_integer_value(json_object_get(object, "bar")) != 2)
+        fail("json_object_update_missing_new updated wrong key");
+
+    if(json_integer_value(json_object_get(object, "baz")) != 4)
+        fail("json_object_update_missing_new didn't add new items");
+
     json_decref(object);
     json_decref(other);
 }