1 /*
2 * SysDB - src/include/core/object.h
3 * Copyright (C) 2012 Sebastian 'tokkee' Harl <sh@tokkee.org>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
17 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
18 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR
19 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
20 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
28 #ifndef SDB_CORE_OBJECT_H
29 #define SDB_CORE_OBJECT_H 1
31 #include <stdarg.h>
32 #include <stddef.h>
34 #ifdef __cplusplus
35 extern "C" {
36 #endif
38 struct sdb_type;
39 typedef struct sdb_type sdb_type_t;
41 struct sdb_object;
42 typedef struct sdb_object sdb_object_t;
44 struct sdb_type {
45 size_t size;
47 int (*init)(sdb_object_t *, va_list);
48 void (*destroy)(sdb_object_t *);
49 };
50 #define SDB_TYPE_INIT { 0, NULL, NULL }
52 struct sdb_object {
53 sdb_type_t type;
54 int ref_cnt;
55 };
56 #define SDB_OBJECT_INIT { SDB_TYPE_INIT, 1 }
58 typedef struct {
59 sdb_object_t super;
60 void *data;
61 void (*destructor)(void *);
62 } sdb_object_wrapper_t;
64 #define SDB_OBJ(obj) ((sdb_object_t *)(obj))
65 #define SDB_OBJ_WRAPPER(obj) ((sdb_object_wrapper_t *)(obj))
67 /*
68 * sdb_object_create:
69 * Allocates a new sdb_object_t of the specified 'type'. The object will be
70 * initialized to zero and then passed on to the 'init' function (if
71 * specified). If specified, the 'destroy' callback will be called, when the
72 * reference count drops to zero and before freeing the memory allocated by
73 * the object itself.
74 *
75 * The init function will be called with the remaining arguments passed to
76 * sdb_object_create. If the init function fails (returns a non-zero value),
77 * the object will be destructed and destroyed.
78 *
79 * The reference count of the new object will be 1.
80 *
81 * Returns:
82 * - the newly allocated object
83 * - NULL on error
84 */
85 sdb_object_t *
86 sdb_object_create(sdb_type_t type, ...);
88 /*
89 * sdb_object_create_wrapper:
90 * Create a new sdb_object_t wrapping some arbitrary other object.
91 *
92 * Creation and initialization of the wrapped object needs to happen outside
93 * of the SysDB object system.
94 */
95 sdb_object_t *
96 sdb_object_create_wrapper(void *data, void (*destructor)(void *));
98 #define SDB_OBJECT_WRAPPER_STATIC(obj, destructor) \
99 { SDB_OBJECT_INIT, (obj), (destructor) }
101 /*
102 * sdb_object_deref:
103 * Dereference the object and free the allocated memory in case the ref-count
104 * drops to zero. In case a 'destructor' had been registered with the object,
105 * it will be called before freeing the memory.
106 */
107 void
108 sdb_object_deref(sdb_object_t *obj);
110 /*
111 * sdb_object_ref:
112 * Take ownership of the specified object, that is, increment the reference
113 * count by one.
114 */
115 void
116 sdb_object_ref(sdb_object_t *obj);
118 #ifdef __cplusplus
119 } /* extern "C" */
120 #endif
122 #endif /* ! SDB_CORE_OBJECT_H */
124 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */