astobj2: Add support for weakproxy objects.

This implements "weak" references.  The weakproxy object is a real ao2 with
normal reference counting of its own.  When a weakproxy is pointed to a normal
object they hold references to each other.  The normal object is automatically
freed when a single reference remains (the weakproxy).  The weakproxy also
supports subscriptions that will notify callbacks when it does not point
to any real object.

ASTERISK-24936 #close
Reported by: Corey Farrell

Change-Id: Ib9f73c02262488d314d9d9d62f58165b9ec43c67

include/asterisk/astobj2.h

@@ -19,6 +19,7 @@
 
 #include "asterisk/compat.h"
 #include "asterisk/lock.h"
+#include "asterisk/linkedlists.h"
 
 /*! \file
  * \ref AstObj2
@@ -578,6 +579,155 @@ int __ao2_ref(void *o, int delta);
 
 /*! @} */
 
+/*! \brief ao2_weakproxy
+ *
+ * @{
+ */
+struct ao2_weakproxy_notification;
+typedef void (*ao2_weakproxy_notification_cb)(void *weakproxy, void *data);
+
+/*! \brief This struct should be opaque, but it's size is needed. */
+struct ao2_weakproxy {
+	AST_LIST_HEAD_NOLOCK(, ao2_weakproxy_notification) destroyed_cb;
+};
+
+/*! \brief Macro which must be used at the beginning of weakproxy capable objects.
+ *
+ * \note The primary purpose of user defined fields on weakproxy objects is to hold
+ *       immutable container keys for the real object.
+ */
+#define AO2_WEAKPROXY() struct ao2_weakproxy __weakproxy##__LINE__
+
+/*!
+ * \since 14.0.0
+ * \brief Allocate an ao2_weakproxy object
+ *
+ * \param data_size The sizeof() of the user-defined structure.
+ * \param destructor_fn The destructor function (can be NULL)
+ *
+ * \note "struct ao2_weakproxy" must be the first field of any object.
+ *       This can be done by using AO2_WEAKPROXY to declare your structure.
+ */
+void *__ao2_weakproxy_alloc(size_t data_size, ao2_destructor_fn destructor_fn,
+	const char *tag, const char *file, int line, const char *func) attribute_warn_unused_result;
+
+#define ao2_weakproxy_alloc(data_size, destructor_fn) \
+	__ao2_weakproxy_alloc(data_size, destructor_fn, "", __FILE__, __LINE__, __PRETTY_FUNCTION__)
+
+#define ao2_t_weakproxy_alloc(data_size, destructor_fn, tag) \
+	__ao2_weakproxy_alloc(data_size, destructor_fn, tag, __FILE__, __LINE__, __PRETTY_FUNCTION__)
+
+/*!
+ * \since 14.0.0
+ * \brief Associate weakproxy with obj.
+ *
+ * \param weakproxy An object created by ao2_weakproxy_alloc.
+ * \param obj An ao2 object not created by ao2_weakproxy_alloc.
+ * \param flags OBJ_NOLOCK to avoid locking weakproxy.
+ *
+ * \retval 0 Success
+ * \retval -1 Failure
+ *
+ * \note obj must be newly created, this procedure is not thread safe
+ *       if any other code can reach obj before this procedure ends.
+ *
+ * \note weakproxy may be previously existing, but must not currently
+ *       have an object set.
+ *
+ * \note The only way to unset an object is for it to be destroyed.
+ *       Any call to this function while an object is already set will fail.
+ */
+int __ao2_weakproxy_set_object(void *weakproxy, void *obj, int flags,
+	const char *tag, const char *file, int line, const char *func);
+
+#define ao2_weakproxy_set_object(weakproxy, obj, flags) \
+	__ao2_weakproxy_set_object(weakproxy, obj, flags, "", __FILE__, __LINE__, __PRETTY_FUNCTION__)
+
+#define ao2_t_weakproxy_set_object(weakproxy, obj, flags, tag) \
+	__ao2_weakproxy_set_object(weakproxy, obj, flags, tag, __FILE__, __LINE__, __PRETTY_FUNCTION__)
+
+/*!
+ * \since 14.0.0
+ * \brief Get the object associated with weakproxy.
+ *
+ * \param weakproxy The weakproxy to read from.
+ * \param flags OBJ_NOLOCK to avoid locking weakproxy.
+ *
+ * \return A reference to the object previously set by ao2_weakproxy_set_object.
+ * \retval NULL Either no object was set or the previously set object has been freed.
+ */
+void *__ao2_weakproxy_get_object(void *weakproxy, int flags,
+	const char *tag, const char *file, int line, const char *func) attribute_warn_unused_result;
+
+#define ao2_weakproxy_get_object(weakproxy, flags) \
+	__ao2_weakproxy_get_object(weakproxy, flags, "", __FILE__, __LINE__, __PRETTY_FUNCTION__)
+
+#define ao2_t_weakproxy_get_object(weakproxy, flags, tag) \
+	__ao2_weakproxy_get_object(weakproxy, flags, tag, __FILE__, __LINE__, __PRETTY_FUNCTION__)
+
+/*!
+ * \since 14.0.0
+ * \brief Request notification when weakproxy points to NULL.
+ *
+ * \param weakproxy The weak object
+ * \param cb Procedure to call when no real object is associated
+ * \param data Passed to cb
+ * \param flags OBJ_NOLOCK to avoid locking weakproxy.
+ *
+ * \retval 0 Success
+ * \retval -1 Failure
+ *
+ * \note This procedure will allow the same cb / data pair to be added to
+ *       the same weakproxy multiple times.
+ *
+ * \note It is the caller's responsibility to ensure that *data is valid
+ *       until after cb() is run or ao2_weakproxy_unsubscribe is called.
+ *
+ * \note If the weakproxy currently points to NULL the callback will be run immediately,
+ *       without being added to the subscriber list.
+ */
+int ao2_weakproxy_subscribe(void *weakproxy, ao2_weakproxy_notification_cb cb, void *data, int flags);
+
+/*!
+ * \since 14.0.0
+ * \brief Remove notification of real object destruction.
+ *
+ * \param weakproxy The weak object
+ * \param cb Callback to remove from destroy notification list
+ * \param data Data pointer to match
+ * \param flags OBJ_NOLOCK to avoid locking weakproxy.
+ *              OBJ_MULTIPLE to remove all copies of the same cb / data pair.
+ *
+ * \return The number of subscriptions removed.
+ * \retval 0 cb / data pair not found, nothing removed.
+ * \retval -1 Failure due to invalid parameters.
+ *
+ * \note Unless flags includes OBJ_MULTIPLE, this will only remove a single copy
+ *       of the cb / data pair.  If it was subscribed multiple times it must be
+ *       unsubscribed as many times.  The OBJ_MULTIPLE flag can be used to remove
+ *       matching subscriptions.
+ */
+int ao2_weakproxy_unsubscribe(void *weakproxy, ao2_weakproxy_notification_cb cb, void *data, int flags);
+
+/*!
+ * \since 14.0.0
+ * \brief Get the weakproxy attached to obj
+ *
+ * \param obj The object to retreive a weakproxy from
+ *
+ * \return The weakproxy object
+ */
+void *__ao2_get_weakproxy(void *obj,
+	const char *tag, const char *file, int line, const char *func) attribute_warn_unused_result;
+
+#define ao2_get_weakproxy(obj) \
+	__ao2_get_weakproxy(obj, "", __FILE__, __LINE__, __PRETTY_FUNCTION__)
+
+#define ao2_t_get_weakproxy(obj, tag) \
+	__ao2_get_weakproxy(obj, tag, __FILE__, __LINE__, __PRETTY_FUNCTION__)
+/*! @} */
+
+
 /*! \brief Which lock to request. */
 enum ao2_lock_req {
 	/*! Request the mutex lock be acquired. */

main/astobj2.c

@@ -52,16 +52,20 @@ static FILE *ref_log;
 struct __priv_data {
 	int ref_counter;
 	ao2_destructor_fn destructor_fn;
+	/*! This field is used for astobj2 and ao2_weakproxy objects to reference each other */
+	void *weakptr;
 	/*! User data size for stats */
 	size_t data_size;
 	/*! The ao2 object option flags */
 	uint32_t options;
 	/*! magic number.  This is used to verify that a pointer passed in is a
-	 *  valid astobj2 */
+	 *  valid astobj2 or ao2_weak reference */
 	uint32_t magic;
 };
 
 #define	AO2_MAGIC	0xa570b123
+#define	AO2_WEAK	0xa570b122
+#define IS_AO2_MAGIC_BAD(p) (AO2_MAGIC != (p->priv_data.magic | 1))
 
 /*!
  * What an astobj2 object looks like: fixed-size private data
@@ -72,6 +76,14 @@ struct astobj2 {
 	void *user_data[0];
 };
 
+struct ao2_weakproxy_notification {
+	ao2_weakproxy_notification_cb cb;
+	void *data;
+	AST_LIST_ENTRY(ao2_weakproxy_notification) list;
+};
+
+static void weakproxy_run_callbacks(struct ao2_weakproxy *weakproxy);
+
 struct ao2_lock_priv {
 	ast_mutex_t lock;
 };
@@ -121,7 +133,7 @@ static struct astobj2 *INTERNAL_OBJ(void *user_data)
 	}
 
 	p = (struct astobj2 *) ((char *) user_data - sizeof(*p));
-	if (AO2_MAGIC != p->priv_data.magic) {
+	if (IS_AO2_MAGIC_BAD(p)) {
 		if (p->priv_data.magic) {
 			ast_log(LOG_ERROR, "bad magic number 0x%x for object %p\n",
 				p->priv_data.magic, user_data);
@@ -407,6 +419,7 @@ static int internal_ao2_ref(void *user_data, int delta, const char *file, int li
 	struct astobj2_rwlock *obj_rwlock;
 	int current_value;
 	int ret;
+	void *weakproxy = NULL;
 
 	if (obj == NULL) {
 		ast_assert(0);
@@ -418,6 +431,10 @@ static int internal_ao2_ref(void *user_data, int delta, const char *file, int li
 		return obj->priv_data.ref_counter;
 	}
 
+	if (delta < 0 && obj->priv_data.magic == AO2_MAGIC && (weakproxy = obj->priv_data.weakptr)) {
+		ao2_lock(weakproxy);
+	}
+
 	/* we modify with an atomic operation the reference counter */
 	ret = ast_atomic_fetchadd_int(&obj->priv_data.ref_counter, delta);
 	current_value = ret + delta;
@@ -426,6 +443,29 @@ static int internal_ao2_ref(void *user_data, int delta, const char *file, int li
 	ast_atomic_fetchadd_int(&ao2.total_refs, delta);
 #endif
 
+	if (weakproxy) {
+		if (current_value == 1) {
+			/* The only remaining reference is the one owned by the weak object */
+			struct astobj2 *internal_weakproxy = INTERNAL_OBJ(weakproxy);
+
+			/* Unlink the obj from the weak proxy */
+			internal_weakproxy->priv_data.weakptr = NULL;
+			obj->priv_data.weakptr = NULL;
+
+			/* Notify the subscribers that weakproxy now points to NULL. */
+			weakproxy_run_callbacks(weakproxy);
+
+			/* weak is already unlinked from obj so this won't recurse */
+			ao2_ref(user_data, -1);
+		}
+
+		ao2_unlock(weakproxy);
+
+		if (current_value == 1) {
+			ao2_ref(weakproxy, -1);
+		}
+	}
+
 	if (0 < current_value) {
 		/* The object still lives. */
 		return ret;
@@ -736,6 +776,200 @@ void *__ao2_global_obj_ref(struct ao2_global_obj *holder, const char *tag, const
 	return obj;
 }
 
+
+static void weakproxy_run_callbacks(struct ao2_weakproxy *weakproxy)
+{
+	struct ao2_weakproxy_notification *destroyed_cb;
+
+	while ((destroyed_cb = AST_LIST_REMOVE_HEAD(&weakproxy->destroyed_cb, list))) {
+		destroyed_cb->cb(weakproxy, destroyed_cb->data);
+		ast_free(destroyed_cb);
+	}
+}
+
+void *__ao2_weakproxy_alloc(size_t data_size, ao2_destructor_fn destructor_fn,
+	const char *tag, const char *file, int line, const char *func)
+{
+	struct ao2_weakproxy *weakproxy;
+
+	if (data_size < sizeof(*weakproxy)) {
+		ast_assert(0);
+		ast_log(LOG_ERROR, "Requested data_size smaller than minimum.\n");
+		return NULL;
+	}
+
+	weakproxy = __ao2_alloc_debug(data_size, destructor_fn, AO2_ALLOC_OPT_LOCK_MUTEX,
+		tag, file, line, func, 1);
+
+	if (weakproxy) {
+		struct astobj2 *weakproxy_internal = INTERNAL_OBJ(weakproxy);
+
+		weakproxy_internal->priv_data.magic = AO2_WEAK;
+	}
+
+	return weakproxy;
+}
+
+int __ao2_weakproxy_set_object(void *weakproxy, void *obj, int flags,
+	const char *tag, const char *file, int line, const char *func)
+{
+	struct astobj2 *weakproxy_internal = INTERNAL_OBJ(weakproxy);
+	struct astobj2 *obj_internal = INTERNAL_OBJ(obj);
+	int ret = -1;
+
+	if (!weakproxy_internal
+		|| weakproxy_internal->priv_data.magic != AO2_WEAK) {
+		return -1;
+	}
+
+	if (!obj_internal
+		|| obj_internal->priv_data.weakptr
+		|| obj_internal->priv_data.magic != AO2_MAGIC) {
+		return -1;
+	}
+
+	if (!(flags & OBJ_NOLOCK)) {
+		ao2_lock(weakproxy);
+	}
+
+	if (!weakproxy_internal->priv_data.weakptr) {
+		__ao2_ref_debug(obj, +1, tag, file, line, func);
+		__ao2_ref_debug(weakproxy, +1, tag, file, line, func);
+
+		weakproxy_internal->priv_data.weakptr = obj;
+		obj_internal->priv_data.weakptr = weakproxy;
+
+		ret = 0;
+	}
+
+	if (!(flags & OBJ_NOLOCK)) {
+		ao2_unlock(weakproxy);
+		/* It is possible for obj to be accessed now.  It's allowed
+		 * for weakproxy to already be in a container.  Another thread
+		 * could have been waiting for a lock on weakproxy to retreive
+		 * the object.
+		 */
+	}
+
+	return ret;
+}
+
+void *__ao2_weakproxy_get_object(void *weakproxy, int flags,
+	const char *tag, const char *file, int line, const char *func)
+{
+	struct astobj2 *internal = INTERNAL_OBJ(weakproxy);
+	void *obj;
+
+	if (!internal || internal->priv_data.magic != AO2_WEAK) {
+		/* This method is meant to be run on weakproxy objects! */
+		return NULL;
+	}
+
+	/* We have a weak object, grab reference to object within lock */
+	if (!(flags & OBJ_NOLOCK)) {
+		ao2_lock(weakproxy);
+	}
+
+	obj = internal->priv_data.weakptr;
+	if (obj) {
+		__ao2_ref_debug(obj, +1, tag, file, line, func);
+	}
+
+	if (!(flags & OBJ_NOLOCK)) {
+		ao2_unlock(weakproxy);
+	}
+
+	return obj;
+}
+
+void *__ao2_get_weakproxy(void *obj, const char *tag, const char *file, int line, const char *func)
+{
+	struct astobj2 *obj_internal = INTERNAL_OBJ(obj);
+
+	if (!obj_internal || obj_internal->priv_data.magic != AO2_MAGIC) {
+		/* This method is meant to be run on normal ao2 objects! */
+		return NULL;
+	}
+
+	if (!obj_internal->priv_data.weakptr) {
+		return NULL;
+	}
+
+	__ao2_ref_debug(obj_internal->priv_data.weakptr, +1, tag, file, line, func);
+	return obj_internal->priv_data.weakptr;
+}
+
+int ao2_weakproxy_subscribe(void *weakproxy, ao2_weakproxy_notification_cb cb, void *data, int flags)
+{
+	struct astobj2 *weakproxy_internal = INTERNAL_OBJ(weakproxy);
+	int ret = -1;
+
+	if (!weakproxy_internal || weakproxy_internal->priv_data.magic != AO2_WEAK) {
+		return -1;
+	}
+
+	if (!(flags & OBJ_NOLOCK)) {
+		ao2_lock(weakproxy);
+	}
+
+	if (weakproxy_internal->priv_data.weakptr) {
+		struct ao2_weakproxy *weak = weakproxy;
+		struct ao2_weakproxy_notification *sub = ast_calloc(1, sizeof(*sub));
+
+		if (sub) {
+			sub->cb = cb;
+			sub->data = data;
+			AST_LIST_INSERT_TAIL(&weak->destroyed_cb, sub, list);
+			ret = 0;
+		}
+	} else {
+		cb(weakproxy, data);
+		ret = 0;
+	}
+
+	if (!(flags & OBJ_NOLOCK)) {
+		ao2_unlock(weakproxy);
+	}
+
+	return ret;
+}
+
+int ao2_weakproxy_unsubscribe(void *weakproxy, ao2_weakproxy_notification_cb destroyed_cb, void *data, int flags)
+{
+	struct astobj2 *internal_weakproxy = INTERNAL_OBJ(weakproxy);
+	struct ao2_weakproxy *weak;
+	struct ao2_weakproxy_notification *sub;
+	int ret = 0;
+
+	if (!internal_weakproxy || internal_weakproxy->priv_data.magic != AO2_WEAK || !destroyed_cb) {
+		return -1;
+	}
+
+	if (!(flags & OBJ_NOLOCK)) {
+		ao2_lock(weakproxy);
+	}
+
+	weak = weakproxy;
+	AST_LIST_TRAVERSE_SAFE_BEGIN(&weak->destroyed_cb, sub, list) {
+		if (sub->cb == destroyed_cb && sub->data == data) {
+			AST_LIST_REMOVE_CURRENT(list);
+			ast_free(sub);
+			ret++;
+			if (!(flags & OBJ_MULTIPLE)) {
+				break;
+			}
+		}
+	}
+	AST_LIST_TRAVERSE_SAFE_END;
+
+	if (!(flags & OBJ_NOLOCK)) {
+		ao2_unlock(weakproxy);
+	}
+
+	return ret;
+}
+
+
 #ifdef AO2_DEBUG
 static int print_cb(void *obj, void *arg, int flag)
 {

tests/test_astobj2_weaken.c

@@ -0,0 +1,259 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2015, CFWare, LLC
+ *
+ * Corey Farrell <git@cfware.com>
+ *
+ * See http://www.asterisk.org for more information about
+ * the Asterisk project. Please do not directly contact
+ * any of the maintainers of this project for assistance;
+ * the project provides a web site, mailing lists and IRC
+ * channels for your use.
+ *
+ * This program is free software, distributed under the terms of
+ * the GNU General Public License Version 2. See the LICENSE file
+ * at the top of the source tree.
+ */
+
+/*!
+ * \file
+ * \brief astobj2 weakproxy test module
+ *
+ * \author Corey Farrell <git@cfware.com>
+ */
+
+/*** MODULEINFO
+	<depend>TEST_FRAMEWORK</depend>
+	<support_level>core</support_level>
+ ***/
+
+#include "asterisk.h"
+
+ASTERISK_FILE_VERSION(__FILE__, "$Revision: 419175 $")
+
+#include "asterisk/utils.h"
+#include "asterisk/module.h"
+#include "asterisk/test.h"
+#include "asterisk/astobj2.h"
+
+static int destructor_called;
+static int weakproxydestroyed;
+
+static void test_obj_destructor(void *obj)
+{
+	destructor_called++;
+}
+
+static void weakproxy_destructor(void *obj)
+{
+	weakproxydestroyed++;
+}
+
+static void test_obj_destroy_notify(void *obj, void *data)
+{
+	int *i = data;
+
+	++*i;
+}
+
+struct my_weakproxy {
+	AO2_WEAKPROXY();
+	int f1;
+};
+
+AST_TEST_DEFINE(astobj2_weak1)
+{
+	void *obj1 = NULL;
+	void *obj2 = NULL;
+	void *obj3 = NULL;
+	void *strong1 = NULL;
+	struct my_weakproxy *weakref1 = NULL;
+	struct my_weakproxy *weakref2 = NULL;
+	int notify0_called = 0;
+	int notify1_called = 0;
+	int notify2_called = 0;
+	int notify3_called = 0;
+
+	switch (cmd) {
+	case TEST_INIT:
+		info->name = "astobj2_weak1";
+		info->category = "/main/astobj2/";
+		info->summary = "Test ao2 weak objects";
+		info->description = "Test ao2 weak objects.";
+		return AST_TEST_NOT_RUN;
+	case TEST_EXECUTE:
+		break;
+	}
+
+	destructor_called = weakproxydestroyed = 0;
+	obj1 = ao2_t_alloc(0, test_obj_destructor, "obj1");
+	if (!obj1) {
+		return AST_TEST_FAIL;
+	}
+
+	weakref1 = ao2_t_weakproxy_alloc(sizeof(*weakref1), weakproxy_destructor, "weakref1");
+	if (!weakref1) {
+		ast_test_status_update(test, "Failed to allocate weakref1.\n");
+		goto fail_cleanup;
+	}
+	weakref1->f1 = 5315;
+
+	if (ao2_weakproxy_subscribe(weakref1, test_obj_destroy_notify, &notify0_called, 0)) {
+		ast_test_status_update(test, "Failed to subscribe to weakref1.\n");
+		goto fail_cleanup;
+	}
+	if (!notify0_called) {
+		ast_test_status_update(test, "Subscribe failed to immediately run callback for empty weakproxy.\n");
+		goto fail_cleanup;
+	}
+
+	if (ao2_t_weakproxy_set_object(weakref1, obj1, 0, "set weakref1 to obj1")) {
+		ast_test_status_update(test, "Failed to set obj1 on weakref1.\n");
+		goto fail_cleanup;
+	}
+
+	if (ao2_weakproxy_subscribe(weakref1, test_obj_destroy_notify, &notify1_called, 0)) {
+		ast_test_status_update(test, "Failed to add a subscription to weakref1.\n");
+		goto fail_cleanup;
+	}
+
+	weakref2 = ao2_t_get_weakproxy(obj1, "get weakref2 from obj1");
+	if (weakref1 != weakref2) {
+		ast_test_status_update(test, "weakref1 != weakref2.\n");
+		goto fail_cleanup;
+	}
+
+	if (ao2_weakproxy_subscribe(weakref2, test_obj_destroy_notify, &notify2_called, 0)) {
+		ast_test_status_update(test, "Failed to add a subscription to weakref2.\n");
+		goto fail_cleanup;
+	}
+
+	if (ao2_weakproxy_subscribe(weakref2, test_obj_destroy_notify, &notify2_called, 0)) {
+		ast_test_status_update(test, "Failed to add a duplicate subscription to weakref2.\n");
+		goto fail_cleanup;
+	}
+
+	if (ao2_weakproxy_subscribe(weakref2, test_obj_destroy_notify, &notify2_called, 0)) {
+		ast_test_status_update(test, "Failed to add a second duplicate subscription to weakref2.\n");
+		goto fail_cleanup;
+	}
+
+	if (ao2_weakproxy_unsubscribe(weakref2, test_obj_destroy_notify, &notify2_called, 0) != 1) {
+		ast_test_status_update(test, "Failed to remove a subscription to weakref2.\n");
+		goto fail_cleanup;
+	}
+
+	ao2_t_cleanup(weakref1, "weakref1");
+	ao2_t_cleanup(weakref2, "weakref2");
+
+	weakref2 = ao2_t_get_weakproxy(obj1, "get weakref2 from obj1");
+	if (weakref1 != weakref2) {
+		weakref1 = NULL;
+		ast_test_status_update(test, "weakref1 != weakref2.\n");
+		goto fail_cleanup;
+	}
+	weakref1 = NULL;
+
+	obj2 = ao2_t_alloc(0, NULL, "obj2");
+	if (obj2) {
+		int ret = ao2_t_weakproxy_set_object(weakref2, obj2, 0, "set weakref2 to obj2");
+
+		ao2_ref(obj2, -1);
+		if (!ret) {
+			ast_test_status_update(test, "Set obj2 to weakref2 when it already had an object.\n");
+			goto fail_cleanup;
+		}
+	}
+
+	if (ao2_weakproxy_subscribe(weakref2, test_obj_destroy_notify, &notify3_called, 0)) {
+		ast_test_status_update(test, "Failed to add a subscription to weakref2.\n");
+		goto fail_cleanup;
+	}
+
+	if (ao2_weakproxy_subscribe(weakref2, test_obj_destroy_notify, &notify3_called, 0)) {
+		ast_test_status_update(test, "Failed to add a duplicate subscription to weakref2.\n");
+		goto fail_cleanup;
+	}
+
+	if (ao2_weakproxy_unsubscribe(weakref2, test_obj_destroy_notify, &notify3_called, OBJ_MULTIPLE) != 2) {
+		ast_test_status_update(test, "Failed to remove the correct number of subscriptions to weakref2.\n");
+		goto fail_cleanup;
+	}
+
+	if (destructor_called || notify1_called || notify2_called || notify3_called) {
+		ast_test_status_update(test, "Destructor or notifications called early.\n");
+		goto fail_cleanup;
+	}
+
+	strong1 = ao2_t_weakproxy_get_object(weakref2, 0, "get strong1 from weakref2");
+	ao2_t_cleanup(strong1, "strong1");
+
+	if (obj1 != strong1) {
+		ast_test_status_update(test, "obj1 != strong1.\n");
+		goto fail_cleanup;
+	}
+
+	if (destructor_called || notify1_called || notify2_called || notify3_called) {
+		ast_test_status_update(test, "Destructor or notification called early.\n");
+		goto fail_cleanup;
+	}
+
+	ao2_t_ref(obj1, -1, "obj1");
+	obj1 = NULL;
+
+	if (destructor_called != 1 || notify1_called != 1 || notify2_called != 2 || notify3_called != 0) {
+		ast_test_status_update(test, "Destructor or notification not called the expected number of times.\n");
+		goto fail_cleanup;
+	}
+
+	if (ao2_t_weakproxy_get_object(weakref2, 0, "impossible get of weakref2") != NULL) {
+		ast_test_status_update(test, "Get object on weakref2 worked when it shouldn't\n");
+		goto fail_cleanup;
+	}
+
+	obj3 = ao2_t_alloc(0, test_obj_destructor, "obj3");
+	if (!obj3) {
+		ast_test_status_update(test, "Failed to allocate obj3.\n");
+		goto fail_cleanup;
+	}
+
+	if (ao2_t_weakproxy_set_object(weakref2, obj3, 0, "set weakref2 to obj3")) {
+		ast_test_status_update(test, "Failed to set obj3 to weakref2.\n");
+		goto fail_cleanup;
+	}
+
+	ao2_ref(obj3, -1);
+	ao2_t_ref(weakref2, -1, "weakref2");
+
+	if (!weakproxydestroyed) {
+		ast_test_status_update(test, "Destructor never called for weakproxy, likely a leak.\n");
+		return AST_TEST_FAIL;
+	}
+
+	return AST_TEST_PASS;
+
+fail_cleanup:
+	ao2_cleanup(obj1);
+	ao2_cleanup(obj3);
+	ao2_cleanup(weakref1);
+	ao2_cleanup(weakref2);
+
+	return AST_TEST_FAIL;
+}
+
+static int unload_module(void)
+{
+	AST_TEST_UNREGISTER(astobj2_weak1);
+
+	return 0;
+}
+
+static int load_module(void)
+{
+	AST_TEST_REGISTER(astobj2_weak1);
+
+	return AST_MODULE_LOAD_SUCCESS;
+}
+
+AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "ASTOBJ2 Weak Reference Unit Tests");