[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/babeltrace-internal.h>
#include <babeltrace/assert-internal.h>
#include <stdbool.h>

struct bt_object;

typedef void (*bt_object_release_func)(struct bt_object *);
typedef void (*bt_object_parent_is_owner_listener_func)(
		struct bt_object *);

static inline
void bt_object_get_no_null_check(struct bt_object *obj);

static inline
void bt_object_put_no_null_check(struct bt_object *obj);

/*
 * Babeltrace object base.
 *
 * All objects publicly exposed by Babeltrace APIs must contain this
 * object as their first member.
 */
struct bt_object {
	/*
	 * True if this object is shared, that is, it has a reference
	 * count.
	 */
	bool is_shared;

	/*
	 * Current reference count.
	 */
	unsigned long long ref_count;

	/*
	 * Release function called when the object's reference count
	 * falls to zero. For an object with a parent, this function is
	 * bt_object_with_parent_release_func(), which calls
	 * `spec_release_func` below if there's no current parent.
	 */
	bt_object_release_func release_func;

	/*
	 * Specific release function called by
	 * bt_object_with_parent_release_func() or directly by a
	 * parent object.
	 */
	bt_object_release_func spec_release_func;

	/*
	 * Optional callback for an object with a parent, called by
	 * bt_object_with_parent_release_func() to indicate to the
	 * object that its parent is its owner.
	 */
	bt_object_parent_is_owner_listener_func
		parent_is_owner_listener_func;

	/*
	 * Optional parent object.
	 */
	struct bt_object *parent;
};

static inline
unsigned long long bt_object_get_ref_count(struct bt_object *obj)
{
	BT_ASSERT(obj);
	BT_ASSERT(obj->is_shared);
	return obj->ref_count;
}

static inline
struct bt_object *bt_object_borrow_parent(struct bt_object *obj)
{
	BT_ASSERT(obj);
	BT_ASSERT(obj->is_shared);
	return obj->parent;
}

static inline
struct bt_object *bt_object_get_parent(struct bt_object *obj)
{
	struct bt_object *parent = bt_object_borrow_parent(obj);

	if (parent) {
		bt_object_get_no_null_check(parent);
	}

	return parent;
}

static inline
void bt_object_set_parent(struct bt_object *child, struct bt_object *parent)
{
	BT_ASSERT(child);
	BT_ASSERT(child->is_shared);

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

	/*
	 * It is assumed that a "child" having a parent 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.
	 */
	if (parent) {
		BT_ASSERT(!child->parent);
		child->parent = parent;
		bt_object_get_no_null_check(parent);
	} else {
		if (child->parent) {
			bt_object_put_no_null_check(child->parent);
		}

		child->parent = NULL;
	}
}

static inline
void bt_object_try_spec_release(struct bt_object *obj)
{
	BT_ASSERT(obj);
	BT_ASSERT(obj->is_shared);
	BT_ASSERT(obj->spec_release_func);

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

static inline
void bt_object_with_parent_release_func(struct bt_object *obj)
{
	if (obj->parent) {
		/*
		 * Keep our own copy of the parent address because `obj`
		 * could be destroyed in
		 * obj->parent_is_owner_listener_func().
		 */
		struct bt_object *parent = obj->parent;

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

		if (obj->parent_is_owner_listener_func) {
			/*
			 * 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_func(obj);
		}

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

static inline
void bt_object_init(struct bt_object *obj, bool is_shared,
		bt_object_release_func release_func)
{
	BT_ASSERT(obj);
	BT_ASSERT(!is_shared || release_func);
	obj->is_shared = is_shared;
	obj->release_func = release_func;
	obj->parent_is_owner_listener_func = NULL;
	obj->spec_release_func = NULL;
	obj->parent = NULL;
	obj->ref_count = 1;
}

static inline
void bt_object_init_shared(struct bt_object *obj,
		bt_object_release_func release_func)
{
	bt_object_init(obj, true, release_func);
}

static inline
void bt_object_init_unique(struct bt_object *obj)
{
	bt_object_init(obj, false, NULL);
}

static inline
void bt_object_init_shared_with_parent(struct bt_object *obj,
		bt_object_release_func spec_release_func)
{
	BT_ASSERT(obj);
	BT_ASSERT(spec_release_func);
	bt_object_init_shared(obj, bt_object_with_parent_release_func);
	obj->spec_release_func = spec_release_func;
}

static inline
void bt_object_set_parent_is_owner_listener_func(struct bt_object *obj,
		bt_object_parent_is_owner_listener_func func)
{
	BT_ASSERT(obj);
	BT_ASSERT(obj->is_shared);
	BT_ASSERT(obj->spec_release_func);
	((struct bt_object *) obj)->parent_is_owner_listener_func = func;
}

static inline
void bt_object_inc_ref_count(struct bt_object *obj)
{
	BT_ASSERT(obj);
	BT_ASSERT(obj->is_shared);
	obj->ref_count++;
	BT_ASSERT(obj->ref_count != 0);
}

static inline
void bt_object_get_no_null_check(struct bt_object *obj)
{
	BT_ASSERT(obj);
	BT_ASSERT(obj->is_shared);

	if (unlikely(obj->parent && bt_object_get_ref_count(obj) == 0)) {
#ifdef BT_LOGV
		BT_LOGV("Incrementing object's parent's reference count: "
			"addr=%p, parent-addr=%p", obj, obj->parent);
#endif

		bt_object_get_no_null_check(obj->parent);
	}

#ifdef BT_LOGV
	BT_LOGV("Incrementing object's reference count: %llu -> %llu: "
		"addr=%p, cur-count=%llu, new-count=%llu",
		obj->ref_count, obj->ref_count + 1,
		obj, obj->ref_count, obj->ref_count + 1);
#endif

	bt_object_inc_ref_count(obj);
}

static inline
void bt_object_put_no_null_check(struct bt_object *obj)
{
	BT_ASSERT(obj);
	BT_ASSERT(obj->is_shared);
	BT_ASSERT(obj->ref_count > 0);

#ifdef BT_LOGV
	BT_LOGV("Decrementing object's reference count: %llu -> %llu: "
		"addr=%p, cur-count=%llu, new-count=%llu",
		obj->ref_count, obj->ref_count - 1,
		obj, obj->ref_count, obj->ref_count - 1);
#endif

	obj->ref_count--;

	if (obj->ref_count == 0) {
		BT_ASSERT(obj->release_func);
		obj->release_func(obj);
	}
}

#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/babeltrace-internal.h>
	31	#include <babeltrace/assert-internal.h>
	32	#include <stdbool.h>
	33
	34	struct bt_object;
	35
	36	typedef void (bt_object_release_func)(struct bt_object );
	37	typedef void (*bt_object_parent_is_owner_listener_func)(
	38	struct bt_object *);
	39
	40	static inline
	41	void bt_object_get_no_null_check(struct bt_object *obj);
	42
	43	static inline
	44	void bt_object_put_no_null_check(struct bt_object *obj);
	45
	46	/*
	47	* Babeltrace object base.
	48	*
	49	* All objects publicly exposed by Babeltrace APIs must contain this
	50	* object as their first member.
	51	*/
	52	struct bt_object {
	53	/*
	54	* True if this object is shared, that is, it has a reference
	55	* count.
	56	*/
	57	bool is_shared;
	58
	59	/*
	60	* Current reference count.
	61	*/
	62	unsigned long long ref_count;
	63
	64	/*
	65	* Release function called when the object's reference count
	66	* falls to zero. For an object with a parent, this function is
	67	* bt_object_with_parent_release_func(), which calls
	68	* `spec_release_func` below if there's no current parent.
	69	*/
	70	bt_object_release_func release_func;
	71
	72	/*
	73	* Specific release function called by
	74	* bt_object_with_parent_release_func() or directly by a
	75	* parent object.
	76	*/
	77	bt_object_release_func spec_release_func;
	78
	79	/*
	80	* Optional callback for an object with a parent, called by
	81	* bt_object_with_parent_release_func() to indicate to the
	82	* object that its parent is its owner.
	83	*/
	84	bt_object_parent_is_owner_listener_func
	85	parent_is_owner_listener_func;
	86
	87	/*
	88	* Optional parent object.
	89	*/
	90	struct bt_object *parent;
	91	};
	92
	93	static inline
	94	unsigned long long bt_object_get_ref_count(struct bt_object *obj)
	95	{
	96	BT_ASSERT(obj);
	97	BT_ASSERT(obj->is_shared);
	98	return obj->ref_count;
	99	}
	100
	101	static inline
	102	struct bt_object bt_object_borrow_parent(struct bt_object obj)
	103	{
	104	BT_ASSERT(obj);
	105	BT_ASSERT(obj->is_shared);
	106	return obj->parent;
	107	}
	108
	109	static inline
	110	struct bt_object bt_object_get_parent(struct bt_object obj)
	111	{
	112	struct bt_object *parent = bt_object_borrow_parent(obj);
	113
	114	if (parent) {
	115	bt_object_get_no_null_check(parent);
	116	}
	117
	118	return parent;
	119	}
	120
	121	static inline
	122	void bt_object_set_parent(struct bt_object child, struct bt_object parent)
	123	{
	124	BT_ASSERT(child);
	125	BT_ASSERT(child->is_shared);
	126
	127	#ifdef BT_LOGV
	128	BT_LOGV("Setting object's parent: addr=%p, parent-addr=%p",
	129	child, parent);
	130	#endif
	131
	132	/*
	133	* It is assumed that a "child" having a parent is publicly
	134	* reachable. Therefore, a reference to its parent must be
	135	* taken. The reference to the parent will be released once the
	136	* object's reference count falls to zero.
	137	*/
	138	if (parent) {
	139	BT_ASSERT(!child->parent);
	140	child->parent = parent;
	141	bt_object_get_no_null_check(parent);
	142	} else {
	143	if (child->parent) {
	144	bt_object_put_no_null_check(child->parent);
	145	}
	146
	147	child->parent = NULL;
	148	}
	149	}
	150
	151	static inline
	152	void bt_object_try_spec_release(struct bt_object *obj)
	153	{
	154	BT_ASSERT(obj);
	155	BT_ASSERT(obj->is_shared);
	156	BT_ASSERT(obj->spec_release_func);
	157
	158	if (bt_object_get_ref_count(obj) == 0) {
	159	obj->spec_release_func(obj);
	160	}
	161	}
	162
	163	static inline
	164	void bt_object_with_parent_release_func(struct bt_object *obj)
	165	{
	166	if (obj->parent) {
	167	/*
	168	* Keep our own copy of the parent address because `obj`
	169	* could be destroyed in
	170	* obj->parent_is_owner_listener_func().
	171	*/
	172	struct bt_object *parent = obj->parent;
	173
	174	#ifdef BT_LOGV
	175	BT_LOGV("Releasing parented object: addr=%p, ref-count=%llu, "
	176	"parent-addr=%p, parent-ref-count=%llu",
	177	obj, obj->ref_count,
	178	parent, parent->ref_count);
	179	#endif
	180
	181	if (obj->parent_is_owner_listener_func) {
	182	/*
	183	* Object has a chance to destroy itself here
	184	* under certain conditions and notify its
	185	* parent. At this point the parent is
	186	* guaranteed to exist because it's not put yet.
	187	*/
	188	obj->parent_is_owner_listener_func(obj);
	189	}
	190
	191	/* The release function will be invoked by the parent. */
	192	bt_object_put_no_null_check(parent);
	193	} else {
	194	bt_object_try_spec_release(obj);
	195	}
	196	}
	197
	198	static inline
	199	void bt_object_init(struct bt_object *obj, bool is_shared,
	200	bt_object_release_func release_func)
	201	{
	202	BT_ASSERT(obj);
	203	BT_ASSERT(!is_shared \|\| release_func);
	204	obj->is_shared = is_shared;
	205	obj->release_func = release_func;
	206	obj->parent_is_owner_listener_func = NULL;
	207	obj->spec_release_func = NULL;
	208	obj->parent = NULL;
	209	obj->ref_count = 1;
	210	}
	211
	212	static inline
	213	void bt_object_init_shared(struct bt_object *obj,
	214	bt_object_release_func release_func)
	215	{
	216	bt_object_init(obj, true, release_func);
	217	}
	218
	219	static inline
	220	void bt_object_init_unique(struct bt_object *obj)
	221	{
	222	bt_object_init(obj, false, NULL);
	223	}
	224
	225	static inline
	226	void bt_object_init_shared_with_parent(struct bt_object *obj,
	227	bt_object_release_func spec_release_func)
	228	{
	229	BT_ASSERT(obj);
	230	BT_ASSERT(spec_release_func);
	231	bt_object_init_shared(obj, bt_object_with_parent_release_func);
	232	obj->spec_release_func = spec_release_func;
	233	}
	234
	235	static inline
	236	void bt_object_set_parent_is_owner_listener_func(struct bt_object *obj,
	237	bt_object_parent_is_owner_listener_func func)
	238	{
	239	BT_ASSERT(obj);
	240	BT_ASSERT(obj->is_shared);
	241	BT_ASSERT(obj->spec_release_func);
	242	((struct bt_object *) obj)->parent_is_owner_listener_func = func;
	243	}
	244
	245	static inline
	246	void bt_object_inc_ref_count(struct bt_object *obj)
	247	{
	248	BT_ASSERT(obj);
	249	BT_ASSERT(obj->is_shared);
	250	obj->ref_count++;
	251	BT_ASSERT(obj->ref_count != 0);
	252	}
	253
	254	static inline
	255	void bt_object_get_no_null_check(struct bt_object *obj)
	256	{
	257	BT_ASSERT(obj);
	258	BT_ASSERT(obj->is_shared);
	259
	260	if (unlikely(obj->parent && bt_object_get_ref_count(obj) == 0)) {
	261	#ifdef BT_LOGV
	262	BT_LOGV("Incrementing object's parent's reference count: "
	263	"addr=%p, parent-addr=%p", obj, obj->parent);
	264	#endif
	265
	266	bt_object_get_no_null_check(obj->parent);
	267	}
	268
	269	#ifdef BT_LOGV
	270	BT_LOGV("Incrementing object's reference count: %llu -> %llu: "
	271	"addr=%p, cur-count=%llu, new-count=%llu",
	272	obj->ref_count, obj->ref_count + 1,
	273	obj, obj->ref_count, obj->ref_count + 1);
	274	#endif
	275
	276	bt_object_inc_ref_count(obj);
	277	}
	278
	279	static inline
	280	void bt_object_put_no_null_check(struct bt_object *obj)
	281	{
	282	BT_ASSERT(obj);
	283	BT_ASSERT(obj->is_shared);
	284	BT_ASSERT(obj->ref_count > 0);
	285
	286	#ifdef BT_LOGV
	287	BT_LOGV("Decrementing object's reference count: %llu -> %llu: "
	288	"addr=%p, cur-count=%llu, new-count=%llu",
	289	obj->ref_count, obj->ref_count - 1,
	290	obj, obj->ref_count, obj->ref_count - 1);
	291	#endif
	292
	293	obj->ref_count--;
	294
	295	if (obj->ref_count == 0) {
	296	BT_ASSERT(obj->release_func);
	297	obj->release_func(obj);
	298	}
	299	}
	300
	301	#endif /* BABELTRACE_OBJECT_INTERNAL_H */