--- /dev/null
+#ifndef BABELTRACE_CTF_WRITER_OBJECT_INTERNAL_H
+#define BABELTRACE_CTF_WRITER_OBJECT_INTERNAL_H
+
+/*
+ * 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_ctf_object;
+
+typedef void (*bt_ctf_object_release_func)(struct bt_ctf_object *);
+typedef void (*bt_ctf_object_parent_is_owner_listener_func)(
+ struct bt_ctf_object *);
+
+static inline
+void *bt_ctf_object_get_no_null_check(struct bt_ctf_object *obj);
+
+static inline
+void bt_ctf_object_put_no_null_check(struct bt_ctf_object *obj);
+
+/*
+ * Babeltrace object base.
+ *
+ * All objects publicly exposed by Babeltrace APIs must contain this
+ * object as their first member.
+ */
+struct bt_ctf_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_ctf_object_with_parent_release_func(), which calls
+ * `spec_release_func` below if there's no current parent.
+ */
+ bt_ctf_object_release_func release_func;
+
+ /*
+ * Specific release function called by
+ * bt_ctf_object_with_parent_release_func() or directly by a
+ * parent object.
+ */
+ bt_ctf_object_release_func spec_release_func;
+
+ /*
+ * Optional callback for an object with a parent, called by
+ * bt_ctf_object_with_parent_release_func() to indicate to the
+ * object that its parent is its owner.
+ */
+ bt_ctf_object_parent_is_owner_listener_func
+ parent_is_owner_listener_func;
+
+ /*
+ * Optional parent object.
+ */
+ struct bt_ctf_object *parent;
+};
+
+static inline
+unsigned long long bt_ctf_object_get_ref_count(struct bt_ctf_object *obj)
+{
+ BT_ASSERT(obj);
+ BT_ASSERT(obj->is_shared);
+ return obj->ref_count;
+}
+
+static inline
+struct bt_ctf_object *bt_ctf_object_borrow_parent(struct bt_ctf_object *obj)
+{
+ BT_ASSERT(obj);
+ BT_ASSERT(obj->is_shared);
+ return obj->parent;
+}
+
+static inline
+struct bt_ctf_object *bt_ctf_object_get_parent(struct bt_ctf_object *obj)
+{
+ struct bt_ctf_object *parent = bt_ctf_object_borrow_parent(obj);
+
+ if (parent) {
+ bt_ctf_object_get_no_null_check(parent);
+ }
+
+ return parent;
+}
+
+static inline
+void bt_ctf_object_set_parent(struct bt_ctf_object *child, struct bt_ctf_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_ctf_object_get_no_null_check(parent);
+ } else {
+ if (child->parent) {
+ bt_ctf_object_put_no_null_check(child->parent);
+ }
+
+ child->parent = NULL;
+ }
+}
+
+static inline
+void bt_ctf_object_try_spec_release(struct bt_ctf_object *obj)
+{
+ BT_ASSERT(obj);
+ BT_ASSERT(obj->is_shared);
+ BT_ASSERT(obj->spec_release_func);
+
+ if (bt_ctf_object_get_ref_count(obj) == 0) {
+ obj->spec_release_func(obj);
+ }
+}
+
+static inline
+void bt_ctf_object_with_parent_release_func(struct bt_ctf_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_ctf_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_ctf_object_put_no_null_check(parent);
+ } else {
+ bt_ctf_object_try_spec_release(obj);
+ }
+}
+
+static inline
+void bt_ctf_object_init(struct bt_ctf_object *obj, bool is_shared,
+ bt_ctf_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_ctf_object_init_shared(struct bt_ctf_object *obj,
+ bt_ctf_object_release_func release_func)
+{
+ bt_ctf_object_init(obj, true, release_func);
+}
+
+static inline
+void bt_ctf_object_init_unique(struct bt_ctf_object *obj)
+{
+ bt_ctf_object_init(obj, false, NULL);
+}
+
+static inline
+void bt_ctf_object_init_shared_with_parent(struct bt_ctf_object *obj,
+ bt_ctf_object_release_func spec_release_func)
+{
+ BT_ASSERT(obj);
+ BT_ASSERT(spec_release_func);
+ bt_ctf_object_init_shared(obj, bt_ctf_object_with_parent_release_func);
+ obj->spec_release_func = spec_release_func;
+}
+
+static inline
+void bt_ctf_object_set_parent_is_owner_listener_func(struct bt_ctf_object *obj,
+ bt_ctf_object_parent_is_owner_listener_func func)
+{
+ BT_ASSERT(obj);
+ BT_ASSERT(obj->is_shared);
+ BT_ASSERT(obj->spec_release_func);
+ ((struct bt_ctf_object *) obj)->parent_is_owner_listener_func = func;
+}
+
+static inline
+void bt_ctf_object_inc_ref_count(struct bt_ctf_object *obj)
+{
+ BT_ASSERT(obj);
+ BT_ASSERT(obj->is_shared);
+ obj->ref_count++;
+ BT_ASSERT(obj->ref_count != 0);
+}
+
+static inline
+void *bt_ctf_object_get_no_null_check_no_parent_check(struct bt_ctf_object *obj)
+{
+ BT_ASSERT(obj);
+ BT_ASSERT(obj->is_shared);
+
+#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_ctf_object_inc_ref_count(obj);
+ return obj;
+}
+
+static inline
+void *bt_ctf_object_get_no_null_check(struct bt_ctf_object *obj)
+{
+ BT_ASSERT(obj);
+ BT_ASSERT(obj->is_shared);
+
+ if (unlikely(obj->parent && bt_ctf_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_ctf_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_ctf_object_inc_ref_count(obj);
+ return obj;
+}
+
+static inline
+void bt_ctf_object_put_no_null_check(struct bt_ctf_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_CTF_WRITER_OBJECT_INTERNAL_H */
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