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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 | * mechanism 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 release function. */ | |
42 | bt_object_release_func release; | |
43 | /* @see doc/ref-counting.md */ | |
44 | struct bt_object *parent; | |
45 | }; | |
46 | ||
47 | static inline | |
48 | long bt_object_get_ref_count(const void *); | |
49 | static inline | |
50 | void bt_object_set_parent(void *, void *); | |
51 | ||
52 | static | |
53 | void bt_object_release(void *ptr) | |
54 | { | |
55 | struct bt_object *obj = ptr; | |
56 | ||
57 | if (obj && obj->release && !bt_object_get_ref_count(obj)) { | |
58 | obj->release(obj); | |
59 | } | |
60 | } | |
61 | ||
62 | static | |
63 | void generic_release(struct bt_object *obj) | |
64 | { | |
65 | if (obj->parent) { | |
66 | /* The release function will be invoked by the parent. */ | |
67 | bt_put(obj->parent); | |
68 | } else { | |
69 | bt_object_release(obj); | |
70 | } | |
71 | } | |
72 | ||
73 | static inline | |
74 | struct bt_object *bt_object_get_parent(void *ptr) | |
75 | { | |
76 | struct bt_object *obj = ptr; | |
77 | ||
78 | return ptr ? bt_get(obj->parent) : NULL; | |
79 | } | |
80 | ||
81 | static inline | |
82 | void bt_object_set_parent(void *child_ptr, void *parent) | |
83 | { | |
84 | struct bt_object *child = child_ptr; | |
85 | ||
86 | if (!child) { | |
87 | return; | |
88 | } | |
89 | ||
90 | /* | |
91 | * It is assumed that a "child" being "parented" is publicly reachable. | |
92 | * Therefore, a reference to its parent must be taken. The reference | |
93 | * to the parent will be released once the object's reference count | |
94 | * falls to zero. | |
95 | */ | |
96 | child->parent = bt_get(parent); | |
97 | } | |
98 | ||
99 | static inline | |
100 | void bt_object_init(void *ptr, bt_object_release_func release) | |
101 | { | |
102 | struct bt_object *obj = ptr; | |
103 | ||
104 | obj->release = release; | |
105 | obj->parent = NULL; | |
106 | bt_ref_init(&obj->ref_count, generic_release); | |
107 | } | |
108 | ||
109 | static inline | |
110 | long bt_object_get_ref_count(const void *ptr) | |
111 | { | |
112 | const struct bt_object *obj = ptr; | |
113 | ||
114 | return obj->ref_count.count; | |
115 | } | |
116 | ||
117 | #endif /* BABELTRACE_OBJECT_INTERNAL_H */ |