-#ifndef _BABELTRACE_INTERNAL_H
-#define _BABELTRACE_INTERNAL_H
-
/*
- * Copyright 2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
+ * SPDX-License-Identifier: MIT
*
- * The above copyright notice and this permission notice shall be included in
- * all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
- * SOFTWARE.
+ * Copyright 2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
*/
+#ifndef _BABELTRACE_INTERNAL_H
+#define _BABELTRACE_INTERNAL_H
#define bt_max_t(type, a, b) \
((type) (a) > (type) (b) ? (type) (a) : (type) (b))
#define BT_HIDDEN __attribute__((visibility("hidden")))
#endif
+/*
+ * Yield `ref`'s value while setting `ref` to NULL.
+ *
+ * This can be used to give a strong reference to a callee:
+ *
+ * add_foo_to_list(list, BT_MOVE_REF(foo));
+ *
+ * or in a simple assignment:
+ *
+ * my_struct->foo = BT_MOVE_REF(foo);
+ *
+ * When moving a reference in a function call, the reference is given to the
+ * callee even if that function call fails, so make sure the called function
+ * is written accordingly.
+ */
+
+#define BT_MOVE_REF(ref) \
+ ({ \
+ typeof(ref) _ref = ref; \
+ ref = NULL; \
+ _ref; \
+ })
+
#endif