Add acquire_value API to simplify caller code

JerryScript-DCO-1.0-Signed-off-by: François Baldassari francois@pebble.com

Author: François Baldassari

jerry-core/jerry-api.h

@@ -272,6 +272,7 @@ jerry_api_value_t jerry_api_create_string_value (jerry_api_string_t *value);
 jerry_api_size_t jerry_api_string_to_char_buffer (const jerry_api_string_t *, jerry_api_char_t *, jerry_api_size_t);
 jerry_api_string_t *jerry_api_acquire_string (jerry_api_string_t *);
 jerry_api_object_t *jerry_api_acquire_object (jerry_api_object_t *);
+jerry_api_value_t *jerry_api_acquire_value (jerry_api_value_t *);
 
 void jerry_api_release_object (jerry_api_object_t *);
 void jerry_api_release_string (jerry_api_string_t *);

jerry-core/jerry.c

@@ -634,8 +634,41 @@ jerry_api_release_object (jerry_api_object_t *object_p) /**< pointer acquired th
   ecma_deref_object (object_p);
 } /* jerry_api_release_object */
 
+/**
+ * Acquire specified Jerry API value.
+ *
+ * Note:
+ *      For values of string and object types this acquires the underlying data,
+ *      for all other types it is a no-op.
+ *
+ * Warning:
+ *         Acquired pointer should be released with jerry_api_release_value
+ *
+ * @return pointer that may be used outside of the engine
+ */
+jerry_api_value_t *
+jerry_api_acquire_value (jerry_api_value_t *value_p) /**< API value */
+{
+  jerry_assert_api_available ();
+
+  if (value_p->type == JERRY_API_DATA_TYPE_STRING)
+  {
+    jerry_api_acquire_string (value_p->u.v_string);
+  }
+  else if (value_p->type == JERRY_API_DATA_TYPE_OBJECT)
+  {
+    jerry_api_acquire_object (value_p->u.v_object);
+  }
+
+  return value_p;
+} /* jerry_api_acquire_value */
+
 /**
  * Release specified Jerry API value
+ *
+ * Note:
+ *      For values of string and object types this releases the underlying data,
+ *      for all other types it is a no-op.
  */
 void
 jerry_api_release_value (jerry_api_value_t *value_p) /**< API value */