[babeltrace.git] / include / babeltrace / object-internal.h

#ifndef BABELTRACE_OBJECT_INTERNAL_H
#define BABELTRACE_OBJECT_INTERNAL_H

/*
 * Babeltrace - Base object
 *
 * Copyright 2015 Jérémie Galarneau <jeremie.galarneau@efficios.com>
 *
 * Author: Jérémie Galarneau <jeremie.galarneau@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:
 *
 * 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.
 */

#include <babeltrace/ref-internal.h>
#include <babeltrace/ref.h>
#include <babeltrace/assert-internal.h>

/**
 * All objects publicly exposed by Babeltrace APIs must contain this structure
 * as their first member. This allows the unification of all ref counting
 * mechanisms and may be used to provide more base functionality to all
 * objects.
 */
struct bt_object {
	struct bt_ref ref_count;
	/* Class-specific, optional release function. */
	bt_object_release_func release;
	/* Class-specific, optional "parent is owner" notification listener. */
	bt_object_release_func parent_is_owner_listener;
	/* @see doc/ref-counting.md */
	struct bt_object *parent;
};

static inline
long bt_object_get_ref_count(const void *ptr)
{
	const struct bt_object *obj = ptr;

	return obj->ref_count.count;
}

static inline
void bt_object_release(void *ptr)
{
	struct bt_object *obj = ptr;

#ifdef BT_LOGV
	BT_LOGV("Releasing object: addr=%p, ref-count=%lu", ptr,
		obj->ref_count.count);
#endif

	if (obj && obj->release && bt_object_get_ref_count(obj) == 0) {
		obj->release(obj);
	}
}

static inline
void generic_release(struct bt_object *obj)
{
	if (obj->parent) {
		struct bt_object *parent = obj->parent;

#ifdef BT_LOGV
		BT_LOGV("Releasing parented object: addr=%p, ref-count=%lu, "
			"parent-addr=%p, parent-ref-count=%lu",
			obj, obj->ref_count.count,
			parent, parent->ref_count.count);
#endif

		if (obj->parent_is_owner_listener) {
			/*
			 * Object has a chance to destroy itself here
			 * under certain conditions and notify its
			 * parent. At this point the parent is
			 * guaranteed to exist because it's not put yet.
			 */
			obj->parent_is_owner_listener(obj);
		}

		/* The release function will be invoked by the parent. */
		bt_put(parent);
	} else {
		bt_object_release(obj);
	}
}

static inline
struct bt_object *bt_object_borrow_parent(void *ptr)
{
	struct bt_object *obj = ptr;

	return obj ? obj->parent : NULL;
}

static inline
struct bt_object *bt_object_get_parent(void *ptr)
{
	return bt_get(bt_object_borrow_parent(ptr));
}

static inline
void bt_object_set_parent(void *child_ptr, void *parent)
{
	struct bt_object *child = child_ptr;

	if (!child) {
		return;
	}

#ifdef BT_LOGV
	BT_LOGV("Setting object's parent: addr=%p, parent-addr=%p",
		child_ptr, parent);
#endif

	/*
	 * It is assumed that a "child" being "parented" is publicly reachable.
	 * Therefore, a reference to its parent must be taken. The reference
	 * to the parent will be released once the object's reference count
	 * falls to zero.
	 */
	BT_PUT(child->parent);
	child->parent = bt_get(parent);
}

static inline
void bt_object_init(void *ptr, bt_object_release_func release)
{
	struct bt_object *obj = ptr;

	obj->release = release;
	obj->parent = NULL;
	bt_ref_init(&obj->ref_count, generic_release);
}

static inline
void bt_object_set_parent_is_owner_listener(void *obj,
		bt_object_release_func cb)
{
	BT_ASSERT(obj);
	((struct bt_object *) obj)->parent_is_owner_listener = cb;
}

#endif /* BABELTRACE_OBJECT_INTERNAL_H */
Commit	Line	Data
	1	#ifndef BABELTRACE_OBJECT_INTERNAL_H
	2	#define BABELTRACE_OBJECT_INTERNAL_H
	3
	4	/*
	5	* Babeltrace - Base object
	6	*
	7	* Copyright 2015 Jérémie Galarneau <jeremie.galarneau@efficios.com>
	8	*
	9	* Author: Jérémie Galarneau <jeremie.galarneau@efficios.com>
	10	*
	11	* Permission is hereby granted, free of charge, to any person obtaining a copy
	12	* of this software and associated documentation files (the "Software"), to deal
	13	* in the Software without restriction, including without limitation the rights
	14	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
	15	* copies of the Software, and to permit persons to whom the Software is
	16	* furnished to do so, subject to the following conditions:
	17	*
	18	* The above copyright notice and this permission notice shall be included in
	19	* all copies or substantial portions of the Software.
	20	*
	21	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	22	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	23	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
	24	* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	25	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
	26	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
	27	* SOFTWARE.
	28	*/
	29
	30	#include <babeltrace/ref-internal.h>
	31	#include <babeltrace/ref.h>
	32	#include <babeltrace/assert-internal.h>
	33
	34	/**
	35	* All objects publicly exposed by Babeltrace APIs must contain this structure
	36	* as their first member. This allows the unification of all ref counting
	37	* mechanisms and may be used to provide more base functionality to all
	38	* objects.
	39	*/
	40	struct bt_object {
	41	struct bt_ref ref_count;
	42	/* Class-specific, optional release function. */
	43	bt_object_release_func release;
	44	/* Class-specific, optional "parent is owner" notification listener. */
	45	bt_object_release_func parent_is_owner_listener;
	46	/* @see doc/ref-counting.md */
	47	struct bt_object *parent;
	48	};
	49
	50	static inline
	51	long bt_object_get_ref_count(const void *ptr)
	52	{
	53	const struct bt_object *obj = ptr;
	54
	55	return obj->ref_count.count;
	56	}
	57
	58	static inline
	59	void bt_object_release(void *ptr)
	60	{
	61	struct bt_object *obj = ptr;
	62
	63	#ifdef BT_LOGV
	64	BT_LOGV("Releasing object: addr=%p, ref-count=%lu", ptr,
	65	obj->ref_count.count);
	66	#endif
	67
	68	if (obj && obj->release && bt_object_get_ref_count(obj) == 0) {
	69	obj->release(obj);
	70	}
	71	}
	72
	73	static inline
	74	void generic_release(struct bt_object *obj)
	75	{
	76	if (obj->parent) {
	77	struct bt_object *parent = obj->parent;
	78
	79	#ifdef BT_LOGV
	80	BT_LOGV("Releasing parented object: addr=%p, ref-count=%lu, "
	81	"parent-addr=%p, parent-ref-count=%lu",
	82	obj, obj->ref_count.count,
	83	parent, parent->ref_count.count);
	84	#endif
	85
	86	if (obj->parent_is_owner_listener) {
	87	/*
	88	* Object has a chance to destroy itself here
	89	* under certain conditions and notify its
	90	* parent. At this point the parent is
	91	* guaranteed to exist because it's not put yet.
	92	*/
	93	obj->parent_is_owner_listener(obj);
	94	}
	95
	96	/* The release function will be invoked by the parent. */
	97	bt_put(parent);
	98	} else {
	99	bt_object_release(obj);
	100	}
	101	}
	102
	103	static inline
	104	struct bt_object bt_object_borrow_parent(void ptr)
	105	{
	106	struct bt_object *obj = ptr;
	107
	108	return obj ? obj->parent : NULL;
	109	}
	110
	111	static inline
	112	struct bt_object bt_object_get_parent(void ptr)
	113	{
	114	return bt_get(bt_object_borrow_parent(ptr));
	115	}
	116
	117	static inline
	118	void bt_object_set_parent(void child_ptr, void parent)
	119	{
	120	struct bt_object *child = child_ptr;
	121
	122	if (!child) {
	123	return;
	124	}
	125
	126	#ifdef BT_LOGV
	127	BT_LOGV("Setting object's parent: addr=%p, parent-addr=%p",
	128	child_ptr, parent);
	129	#endif
	130
	131	/*
	132	* It is assumed that a "child" being "parented" is publicly reachable.
	133	* Therefore, a reference to its parent must be taken. The reference
	134	* to the parent will be released once the object's reference count
	135	* falls to zero.
	136	*/
	137	BT_PUT(child->parent);
	138	child->parent = bt_get(parent);
	139	}
	140
	141	static inline
	142	void bt_object_init(void *ptr, bt_object_release_func release)
	143	{
	144	struct bt_object *obj = ptr;
	145
	146	obj->release = release;
	147	obj->parent = NULL;
	148	bt_ref_init(&obj->ref_count, generic_release);
	149	}
	150
	151	static inline
	152	void bt_object_set_parent_is_owner_listener(void *obj,
	153	bt_object_release_func cb)
	154	{
	155	BT_ASSERT(obj);
	156	((struct bt_object *) obj)->parent_is_owner_listener = cb;
	157	}
	158
	159	#endif /* BABELTRACE_OBJECT_INTERNAL_H */