| 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/ref-internal.h> |
| 31 | #include <babeltrace/ref.h> |
| 32 | |
| 33 | /** |
| 34 | * All objects publicly exposed by Babeltrace APIs must contain this structure |
| 35 | * as their first member. This allows the unification of all ref counting |
| 36 | * mechanisms and may be used to provide more base functionality to all |
| 37 | * objects. |
| 38 | */ |
| 39 | struct bt_object { |
| 40 | struct bt_ref ref_count; |
| 41 | /* Class-specific, optional release function. */ |
| 42 | bt_object_release_func release; |
| 43 | /* Class-specific, optional "parent is owner" notification listener. */ |
| 44 | bt_object_release_func parent_is_owner_listener; |
| 45 | /* @see doc/ref-counting.md */ |
| 46 | struct bt_object *parent; |
| 47 | }; |
| 48 | |
| 49 | static inline |
| 50 | long bt_object_get_ref_count(const void *ptr) |
| 51 | { |
| 52 | const struct bt_object *obj = ptr; |
| 53 | |
| 54 | return obj->ref_count.count; |
| 55 | } |
| 56 | |
| 57 | static inline |
| 58 | void bt_object_release(void *ptr) |
| 59 | { |
| 60 | struct bt_object *obj = ptr; |
| 61 | |
| 62 | #ifdef BT_LOGV |
| 63 | BT_LOGV("Releasing object: addr=%p, ref-count=%lu", ptr, |
| 64 | obj->ref_count.count); |
| 65 | #endif |
| 66 | |
| 67 | if (obj && obj->release && bt_object_get_ref_count(obj) == 0) { |
| 68 | obj->release(obj); |
| 69 | } |
| 70 | } |
| 71 | |
| 72 | static inline |
| 73 | void generic_release(struct bt_object *obj) |
| 74 | { |
| 75 | if (obj->parent) { |
| 76 | struct bt_object *parent = obj->parent; |
| 77 | |
| 78 | #ifdef BT_LOGV |
| 79 | BT_LOGV("Releasing parented object: addr=%p, ref-count=%lu, " |
| 80 | "parent-addr=%p, parent-ref-count=%lu", |
| 81 | obj, obj->ref_count.count, |
| 82 | parent, parent->ref_count.count); |
| 83 | #endif |
| 84 | |
| 85 | if (obj->parent_is_owner_listener) { |
| 86 | /* |
| 87 | * Object has a chance to destroy itself here |
| 88 | * under certain conditions and notify its |
| 89 | * parent. At this point the parent is |
| 90 | * guaranteed to exist because it's not put yet. |
| 91 | */ |
| 92 | obj->parent_is_owner_listener(obj); |
| 93 | } |
| 94 | |
| 95 | /* The release function will be invoked by the parent. */ |
| 96 | bt_put(parent); |
| 97 | } else { |
| 98 | bt_object_release(obj); |
| 99 | } |
| 100 | } |
| 101 | |
| 102 | static inline |
| 103 | struct bt_object *bt_object_borrow_parent(void *ptr) |
| 104 | { |
| 105 | struct bt_object *obj = ptr; |
| 106 | |
| 107 | return obj ? obj->parent : NULL; |
| 108 | } |
| 109 | |
| 110 | static inline |
| 111 | struct bt_object *bt_object_get_parent(void *ptr) |
| 112 | { |
| 113 | return bt_get(bt_object_borrow_parent(ptr)); |
| 114 | } |
| 115 | |
| 116 | static inline |
| 117 | void bt_object_set_parent(void *child_ptr, void *parent) |
| 118 | { |
| 119 | struct bt_object *child = child_ptr; |
| 120 | |
| 121 | if (!child) { |
| 122 | return; |
| 123 | } |
| 124 | |
| 125 | #ifdef BT_LOGV |
| 126 | BT_LOGV("Setting object's parent: addr=%p, parent-addr=%p", |
| 127 | child_ptr, parent); |
| 128 | #endif |
| 129 | |
| 130 | /* |
| 131 | * It is assumed that a "child" being "parented" is publicly reachable. |
| 132 | * Therefore, a reference to its parent must be taken. The reference |
| 133 | * to the parent will be released once the object's reference count |
| 134 | * falls to zero. |
| 135 | */ |
| 136 | BT_PUT(child->parent); |
| 137 | child->parent = bt_get(parent); |
| 138 | } |
| 139 | |
| 140 | static inline |
| 141 | void bt_object_init(void *ptr, bt_object_release_func release) |
| 142 | { |
| 143 | struct bt_object *obj = ptr; |
| 144 | |
| 145 | obj->release = release; |
| 146 | obj->parent = NULL; |
| 147 | bt_ref_init(&obj->ref_count, generic_release); |
| 148 | } |
| 149 | |
| 150 | static inline |
| 151 | void bt_object_set_parent_is_owner_listener(void *obj, |
| 152 | bt_object_release_func cb) |
| 153 | { |
| 154 | assert(obj); |
| 155 | ((struct bt_object *) obj)->parent_is_owner_listener = cb; |
| 156 | } |
| 157 | |
| 158 | #endif /* BABELTRACE_OBJECT_INTERNAL_H */ |