[babeltrace.git] / src / lib / object.h

/*
 * SPDX-License-Identifier: MIT
 *
 * Copyright 2017-2018 Philippe Proulx <pproulx@efficios.com>
 * Copyright 2015 Jérémie Galarneau <jeremie.galarneau@efficios.com>
 */

#ifndef BABELTRACE_OBJECT_INTERNAL_H
#define BABELTRACE_OBJECT_INTERNAL_H

#include "common/macros.h"
#include "common/assert.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_ref_no_null_check(const void *obj);

static inline
void bt_object_put_ref_no_null_check(const void *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(const struct bt_object *c_obj)
{
	struct bt_object *obj = (void *) c_obj;

	BT_ASSERT_DBG(obj);
	BT_ASSERT_DBG(obj->is_shared);
	return obj->ref_count;
}

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

	BT_ASSERT_DBG(obj);
	BT_ASSERT_DBG(obj->is_shared);
	return obj->parent;
}

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

	if (parent) {
		bt_object_get_ref_no_null_check(parent);
	}

	return parent;
}

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

#ifdef BT_LOGT
	BT_LOGT("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_DBG(!child->parent);
		child->parent = parent;
		bt_object_get_ref_no_null_check(parent);
	} else {
		if (child->parent) {
			bt_object_put_ref_no_null_check(child->parent);
		}

		child->parent = NULL;
	}
}

static inline
void bt_object_try_spec_release(struct bt_object *obj)
{
	BT_ASSERT_DBG(obj);
	BT_ASSERT_DBG(obj->is_shared);
	BT_ASSERT_DBG(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_LOGT
		BT_LOGT("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_ref_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_DBG(obj);
	BT_ASSERT_DBG(!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_DBG(obj);
	BT_ASSERT_DBG(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_DBG(obj);
	BT_ASSERT_DBG(obj->is_shared);
	BT_ASSERT_DBG(obj->spec_release_func);
	((struct bt_object *) obj)->parent_is_owner_listener_func = func;
}

static inline
void bt_object_inc_ref_count(const struct bt_object *c_obj)
{
	struct bt_object *obj = (void *) c_obj;

	BT_ASSERT_DBG(obj);
	BT_ASSERT_DBG(obj->is_shared);
	obj->ref_count++;
	BT_ASSERT_DBG(obj->ref_count != 0);
}

static inline
void bt_object_get_ref_no_null_check_no_parent_check(const struct bt_object *c_obj)
{
	struct bt_object *obj = (void *) c_obj;

	BT_ASSERT_DBG(obj);
	BT_ASSERT_DBG(obj->is_shared);

#ifdef BT_LOGT
	BT_LOGT("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_get_ref_no_null_check(const void *c_obj)
{
	struct bt_object *obj = (void *) c_obj;

	BT_ASSERT_DBG(obj);
	BT_ASSERT_DBG(obj->is_shared);

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

		bt_object_get_ref_no_null_check(obj->parent);
	}

#ifdef BT_LOGT
	BT_LOGT("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_ref_no_null_check(const void *c_obj)
{
	struct bt_object *obj = (void *) c_obj;

	BT_ASSERT_DBG(obj);
	BT_ASSERT_DBG(obj->is_shared);
	BT_ASSERT_DBG(obj->ref_count > 0);

#ifdef BT_LOGT
	BT_LOGT("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_DBG(obj->release_func);
		obj->release_func(obj);
	}
}

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

	if (G_UNLIKELY(!obj)) {
		return;
	}

#ifdef BT_ASSERT_PRE_DEV
	BT_ASSERT_PRE_DEV(obj->is_shared, "Object is not shared: %!+O", obj);
#endif

	bt_object_get_ref_no_null_check(obj);
}

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

	if (G_UNLIKELY(!obj)) {
		return;
	}

#ifdef BT_ASSERT_PRE_DEV
	BT_ASSERT_PRE_DEV(obj->is_shared, "Object is not shared: %!+O", obj);
	BT_ASSERT_PRE_DEV(bt_object_get_ref_count(obj) > 0,
		"Decrementing a reference count set to 0: %!+O", ptr);
#endif

	bt_object_put_ref_no_null_check(obj);
}

#define BT_OBJECT_PUT_REF_AND_RESET(_var)	\
	do {					\
		bt_object_put_ref(_var);	\
		(_var) = NULL;			\
	} while (0)

#define BT_OBJECT_MOVE_REF(_var_dst, _var_src)	\
	do {					\
		bt_object_put_ref(_var_dst);	\
		(_var_dst) = (_var_src);	\
		(_var_src) = NULL;		\
	} while (0)

#endif /* BABELTRACE_OBJECT_INTERNAL_H */
Commit	Line	Data
	1	/*
	2	* SPDX-License-Identifier: MIT
	3	*
	4	* Copyright 2017-2018 Philippe Proulx <pproulx@efficios.com>
	5	* Copyright 2015 Jérémie Galarneau <jeremie.galarneau@efficios.com>
	6	*/
	7
	8	#ifndef BABELTRACE_OBJECT_INTERNAL_H
	9	#define BABELTRACE_OBJECT_INTERNAL_H
	10
	11	#include "common/macros.h"
	12	#include "common/assert.h"
	13	#include <stdbool.h>
	14
	15	struct bt_object;
	16
	17	typedef void (bt_object_release_func)(struct bt_object );
	18	typedef void (*bt_object_parent_is_owner_listener_func)(
	19	struct bt_object *);
	20
	21	static inline
	22	void bt_object_get_ref_no_null_check(const void *obj);
	23
	24	static inline
	25	void bt_object_put_ref_no_null_check(const void *obj);
	26
	27	/*
	28	* Babeltrace object base.
	29	*
	30	* All objects publicly exposed by Babeltrace APIs must contain this
	31	* object as their first member.
	32	*/
	33	struct bt_object {
	34	/*
	35	* True if this object is shared, that is, it has a reference
	36	* count.
	37	*/
	38	bool is_shared;
	39
	40	/*
	41	* Current reference count.
	42	*/
	43	unsigned long long ref_count;
	44
	45	/*
	46	* Release function called when the object's reference count
	47	* falls to zero. For an object with a parent, this function is
	48	* bt_object_with_parent_release_func(), which calls
	49	* `spec_release_func` below if there's no current parent.
	50	*/
	51	bt_object_release_func release_func;
	52
	53	/*
	54	* Specific release function called by
	55	* bt_object_with_parent_release_func() or directly by a
	56	* parent object.
	57	*/
	58	bt_object_release_func spec_release_func;
	59
	60	/*
	61	* Optional callback for an object with a parent, called by
	62	* bt_object_with_parent_release_func() to indicate to the
	63	* object that its parent is its owner.
	64	*/
	65	bt_object_parent_is_owner_listener_func
	66	parent_is_owner_listener_func;
	67
	68	/*
	69	* Optional parent object.
	70	*/
	71	struct bt_object *parent;
	72	};
	73
	74	static inline
	75	unsigned long long bt_object_get_ref_count(const struct bt_object *c_obj)
	76	{
	77	struct bt_object obj = (void ) c_obj;
	78
	79	BT_ASSERT_DBG(obj);
	80	BT_ASSERT_DBG(obj->is_shared);
	81	return obj->ref_count;
	82	}
	83
	84	static inline
	85	struct bt_object bt_object_borrow_parent(const struct bt_object c_obj)
	86	{
	87	struct bt_object obj = (void ) c_obj;
	88
	89	BT_ASSERT_DBG(obj);
	90	BT_ASSERT_DBG(obj->is_shared);
	91	return obj->parent;
	92	}
	93
	94	static inline
	95	struct bt_object bt_object_get_parent(const struct bt_object c_obj)
	96	{
	97	struct bt_object obj = (void ) c_obj;
	98	struct bt_object *parent = bt_object_borrow_parent(obj);
	99
	100	if (parent) {
	101	bt_object_get_ref_no_null_check(parent);
	102	}
	103
	104	return parent;
	105	}
	106
	107	static inline
	108	void bt_object_set_parent(struct bt_object child, struct bt_object parent)
	109	{
	110	BT_ASSERT_DBG(child);
	111	BT_ASSERT_DBG(child->is_shared);
	112
	113	#ifdef BT_LOGT
	114	BT_LOGT("Setting object's parent: addr=%p, parent-addr=%p",
	115	child, parent);
	116	#endif
	117
	118	/*
	119	* It is assumed that a "child" having a parent is publicly
	120	* reachable. Therefore, a reference to its parent must be
	121	* taken. The reference to the parent will be released once the
	122	* object's reference count falls to zero.
	123	*/
	124	if (parent) {
	125	BT_ASSERT_DBG(!child->parent);
	126	child->parent = parent;
	127	bt_object_get_ref_no_null_check(parent);
	128	} else {
	129	if (child->parent) {
	130	bt_object_put_ref_no_null_check(child->parent);
	131	}
	132
	133	child->parent = NULL;
	134	}
	135	}
	136
	137	static inline
	138	void bt_object_try_spec_release(struct bt_object *obj)
	139	{
	140	BT_ASSERT_DBG(obj);
	141	BT_ASSERT_DBG(obj->is_shared);
	142	BT_ASSERT_DBG(obj->spec_release_func);
	143
	144	if (bt_object_get_ref_count(obj) == 0) {
	145	obj->spec_release_func(obj);
	146	}
	147	}
	148
	149	static inline
	150	void bt_object_with_parent_release_func(struct bt_object *obj)
	151	{
	152	if (obj->parent) {
	153	/*
	154	* Keep our own copy of the parent address because `obj`
	155	* could be destroyed in
	156	* obj->parent_is_owner_listener_func().
	157	*/
	158	struct bt_object *parent = obj->parent;
	159
	160	#ifdef BT_LOGT
	161	BT_LOGT("Releasing parented object: addr=%p, ref-count=%llu, "
	162	"parent-addr=%p, parent-ref-count=%llu",
	163	obj, obj->ref_count,
	164	parent, parent->ref_count);
	165	#endif
	166
	167	if (obj->parent_is_owner_listener_func) {
	168	/*
	169	* Object has a chance to destroy itself here
	170	* under certain conditions and notify its
	171	* parent. At this point the parent is
	172	* guaranteed to exist because it's not put yet.
	173	*/
	174	obj->parent_is_owner_listener_func(obj);
	175	}
	176
	177	/* The release function will be invoked by the parent. */
	178	bt_object_put_ref_no_null_check(parent);
	179	} else {
	180	bt_object_try_spec_release(obj);
	181	}
	182	}
	183
	184	static inline
	185	void bt_object_init(struct bt_object *obj, bool is_shared,
	186	bt_object_release_func release_func)
	187	{
	188	BT_ASSERT_DBG(obj);
	189	BT_ASSERT_DBG(!is_shared \|\| release_func);
	190	obj->is_shared = is_shared;
	191	obj->release_func = release_func;
	192	obj->parent_is_owner_listener_func = NULL;
	193	obj->spec_release_func = NULL;
	194	obj->parent = NULL;
	195	obj->ref_count = 1;
	196	}
	197
	198	static inline
	199	void bt_object_init_shared(struct bt_object *obj,
	200	bt_object_release_func release_func)
	201	{
	202	bt_object_init(obj, true, release_func);
	203	}
	204
	205	static inline
	206	void bt_object_init_unique(struct bt_object *obj)
	207	{
	208	bt_object_init(obj, false, NULL);
	209	}
	210
	211	static inline
	212	void bt_object_init_shared_with_parent(struct bt_object *obj,
	213	bt_object_release_func spec_release_func)
	214	{
	215	BT_ASSERT_DBG(obj);
	216	BT_ASSERT_DBG(spec_release_func);
	217	bt_object_init_shared(obj, bt_object_with_parent_release_func);
	218	obj->spec_release_func = spec_release_func;
	219	}
	220
	221	static inline
	222	void bt_object_set_parent_is_owner_listener_func(struct bt_object *obj,
	223	bt_object_parent_is_owner_listener_func func)
	224	{
	225	BT_ASSERT_DBG(obj);
	226	BT_ASSERT_DBG(obj->is_shared);
	227	BT_ASSERT_DBG(obj->spec_release_func);
	228	((struct bt_object *) obj)->parent_is_owner_listener_func = func;
	229	}
	230
	231	static inline
	232	void bt_object_inc_ref_count(const struct bt_object *c_obj)
	233	{
	234	struct bt_object obj = (void ) c_obj;
	235
	236	BT_ASSERT_DBG(obj);
	237	BT_ASSERT_DBG(obj->is_shared);
	238	obj->ref_count++;
	239	BT_ASSERT_DBG(obj->ref_count != 0);
	240	}
	241
	242	static inline
	243	void bt_object_get_ref_no_null_check_no_parent_check(const struct bt_object *c_obj)
	244	{
	245	struct bt_object obj = (void ) c_obj;
	246
	247	BT_ASSERT_DBG(obj);
	248	BT_ASSERT_DBG(obj->is_shared);
	249
	250	#ifdef BT_LOGT
	251	BT_LOGT("Incrementing object's reference count: %llu -> %llu: "
	252	"addr=%p, cur-count=%llu, new-count=%llu",
	253	obj->ref_count, obj->ref_count + 1,
	254	obj, obj->ref_count, obj->ref_count + 1);
	255	#endif
	256
	257	bt_object_inc_ref_count(obj);
	258	}
	259
	260	static inline
	261	void bt_object_get_ref_no_null_check(const void *c_obj)
	262	{
	263	struct bt_object obj = (void ) c_obj;
	264
	265	BT_ASSERT_DBG(obj);
	266	BT_ASSERT_DBG(obj->is_shared);
	267
	268	if (G_UNLIKELY(obj->parent && bt_object_get_ref_count(obj) == 0)) {
	269	#ifdef BT_LOGT
	270	BT_LOGT("Incrementing object's parent's reference count: "
	271	"addr=%p, parent-addr=%p", obj, obj->parent);
	272	#endif
	273
	274	bt_object_get_ref_no_null_check(obj->parent);
	275	}
	276
	277	#ifdef BT_LOGT
	278	BT_LOGT("Incrementing object's reference count: %llu -> %llu: "
	279	"addr=%p, cur-count=%llu, new-count=%llu",
	280	obj->ref_count, obj->ref_count + 1,
	281	obj, obj->ref_count, obj->ref_count + 1);
	282	#endif
	283
	284	bt_object_inc_ref_count(obj);
	285	}
	286
	287	static inline
	288	void bt_object_put_ref_no_null_check(const void *c_obj)
	289	{
	290	struct bt_object obj = (void ) c_obj;
	291
	292	BT_ASSERT_DBG(obj);
	293	BT_ASSERT_DBG(obj->is_shared);
	294	BT_ASSERT_DBG(obj->ref_count > 0);
	295
	296	#ifdef BT_LOGT
	297	BT_LOGT("Decrementing object's reference count: %llu -> %llu: "
	298	"addr=%p, cur-count=%llu, new-count=%llu",
	299	obj->ref_count, obj->ref_count - 1,
	300	obj, obj->ref_count, obj->ref_count - 1);
	301	#endif
	302
	303	obj->ref_count--;
	304
	305	if (obj->ref_count == 0) {
	306	BT_ASSERT_DBG(obj->release_func);
	307	obj->release_func(obj);
	308	}
	309	}
	310
	311	static inline
	312	void bt_object_get_ref(const void *ptr)
	313	{
	314	struct bt_object obj = (void ) ptr;
	315
	316	if (G_UNLIKELY(!obj)) {
	317	return;
	318	}
	319
	320	#ifdef BT_ASSERT_PRE_DEV
	321	BT_ASSERT_PRE_DEV(obj->is_shared, "Object is not shared: %!+O", obj);
	322	#endif
	323
	324	bt_object_get_ref_no_null_check(obj);
	325	}
	326
	327	static inline
	328	void bt_object_put_ref(const void *ptr)
	329	{
	330	struct bt_object obj = (void ) ptr;
	331
	332	if (G_UNLIKELY(!obj)) {
	333	return;
	334	}
	335
	336	#ifdef BT_ASSERT_PRE_DEV
	337	BT_ASSERT_PRE_DEV(obj->is_shared, "Object is not shared: %!+O", obj);
	338	BT_ASSERT_PRE_DEV(bt_object_get_ref_count(obj) > 0,
	339	"Decrementing a reference count set to 0: %!+O", ptr);
	340	#endif
	341
	342	bt_object_put_ref_no_null_check(obj);
	343	}
	344
	345	#define BT_OBJECT_PUT_REF_AND_RESET(_var) \
	346	do { \
	347	bt_object_put_ref(_var); \
	348	(_var) = NULL; \
	349	} while (0)
	350
	351	#define BT_OBJECT_MOVE_REF(_var_dst, _var_src) \
	352	do { \
	353	bt_object_put_ref(_var_dst); \
	354	(_var_dst) = (_var_src); \
	355	(_var_src) = NULL; \
	356	} while (0)
	357
	358	#endif /* BABELTRACE_OBJECT_INTERNAL_H */