*/
#include <babeltrace/babeltrace-internal.h>
-#include <babeltrace/ref-internal.h>
-#include <babeltrace/ref.h>
#include <babeltrace/assert-internal.h>
#include <stdbool.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;
+
+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 {
- 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;
-
/*
- * True if this object is shared, that is, it uses reference
- * counting.
+ * 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
-long bt_object_get_ref_count(const void *ptr)
+unsigned long long bt_object_get_ref_count(struct bt_object *obj)
{
- const struct bt_object *obj = ptr;
+ BT_ASSERT(obj);
+ BT_ASSERT(obj->is_shared);
+ return obj->ref_count;
+}
- return obj->ref_count.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
-void bt_object_release(void *ptr)
+struct bt_object *bt_object_get_parent(struct bt_object *obj)
{
- struct bt_object *obj = ptr;
+ 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("Releasing object: addr=%p, ref-count=%lu", ptr,
- obj->ref_count.count);
+ BT_LOGV("Setting object's parent: addr=%p, parent-addr=%p",
+ child, parent);
#endif
- if (obj && obj->release && bt_object_get_ref_count(obj) == 0) {
- obj->release(obj);
+ /*
+ * 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 generic_release(struct bt_object *obj)
+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=%lu, "
- "parent-addr=%p, parent-ref-count=%lu",
- obj, obj->ref_count.count,
- parent, parent->ref_count.count);
+ 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) {
+ 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(obj);
+ obj->parent_is_owner_listener_func(obj);
}
/* The release function will be invoked by the parent. */
- bt_put(parent);
+ bt_object_put_no_null_check(parent);
} else {
- bt_object_release(obj);
+ bt_object_try_spec_release(obj);
}
}
static inline
-struct bt_object *bt_object_borrow_parent(void *ptr)
+void bt_object_init(struct bt_object *obj, bool is_shared,
+ bt_object_release_func release_func)
{
- struct bt_object *obj = ptr;
-
- return obj ? obj->parent : NULL;
+ 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
-struct bt_object *bt_object_get_parent(void *ptr)
+void bt_object_init_shared(struct bt_object *obj,
+ bt_object_release_func release_func)
{
- return bt_get(bt_object_borrow_parent(ptr));
+ bt_object_init(obj, true, release_func);
}
static inline
-void bt_object_set_parent(void *child_ptr, void *parent)
+void bt_object_init_unique(struct bt_object *obj)
{
- struct bt_object *child = child_ptr;
-
- if (!child) {
- return;
- }
+ bt_object_init(obj, false, NULL);
+}
-#ifdef BT_LOGV
- BT_LOGV("Setting object's parent: addr=%p, parent-addr=%p",
- child_ptr, parent);
-#endif
+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;
+}
- /*
- * 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_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_set_is_shared(struct bt_object *obj, bool is_shared)
+void bt_object_inc_ref_count(struct bt_object *obj)
{
- obj->is_shared = is_shared;
+ BT_ASSERT(obj);
+ BT_ASSERT(obj->is_shared);
+ obj->ref_count++;
+ BT_ASSERT(obj->ref_count != 0);
}
static inline
-void bt_object_init(void *ptr, bt_object_release_func release)
+void bt_object_get_no_null_check(struct bt_object *obj)
{
- struct bt_object *obj = ptr;
+ BT_ASSERT(obj);
+ BT_ASSERT(obj->is_shared);
- obj->release = release;
- obj->parent = NULL;
- bt_object_set_is_shared(obj, true);
- bt_ref_init(&obj->ref_count, generic_release);
+ 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_set_parent_is_owner_listener(void *obj,
- bt_object_release_func cb)
+void bt_object_put_no_null_check(struct bt_object *obj)
{
BT_ASSERT(obj);
- ((struct bt_object *) obj)->parent_is_owner_listener = cb;
+ 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 */
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