2f466104c86ee10c3973dc964ce3e80469b29f3c
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 sdb_object_t *(*clone)(const sdb_object_t *);
50 };
51 #define SDB_TYPE_INIT { 0, NULL, NULL, NULL }
53 struct sdb_object {
54 sdb_type_t type;
55 int ref_cnt;
56 };
57 #define SDB_OBJECT_INIT { SDB_TYPE_INIT, 1 }
58 #define SDB_OBJECT_TYPED_INIT(t) { (t), 1 }
60 typedef struct {
61 sdb_object_t super;
62 void *data;
63 void (*destructor)(void *);
64 } sdb_object_wrapper_t;
66 #define SDB_OBJ(obj) ((sdb_object_t *)(obj))
67 #define SDB_CONST_OBJ(obj) ((const sdb_object_t *)(obj))
68 #define SDB_OBJ_WRAPPER(obj) ((sdb_object_wrapper_t *)(obj))
69 #define SDB_CONST_OBJ_WRAPPER(obj) ((const sdb_object_wrapper_t *)(obj))
71 /*
72 * sdb_object_create:
73 * Allocates a new sdb_object_t of the specified 'type'. The object will be
74 * initialized to zero and then passed on to the 'init' function (if
75 * specified). If specified, the 'destroy' callback will be called, when the
76 * reference count drops to zero and before freeing the memory allocated by
77 * the object itself.
78 *
79 * The init function will be called with the remaining arguments passed to
80 * sdb_object_create. If the init function fails (returns a non-zero value),
81 * the object will be destructed and destroyed.
82 *
83 * The reference count of the new object will be 1.
84 *
85 * Returns:
86 * - the newly allocated object
87 * - NULL on error
88 */
89 sdb_object_t *
90 sdb_object_create(sdb_type_t type, ...);
92 /*
93 * sdb_object_create_wrapper:
94 * Create a new sdb_object_t wrapping some arbitrary other object.
95 *
96 * Creation and initialization of the wrapped object needs to happen outside
97 * of the SysDB object system.
98 */
99 sdb_object_t *
100 sdb_object_create_wrapper(void *data, void (*destructor)(void *));
102 #define SDB_OBJECT_WRAPPER_STATIC(obj, destructor) \
103 { SDB_OBJECT_INIT, (obj), (destructor) }
105 /*
106 * sdb_object_deref:
107 * Dereference the object and free the allocated memory in case the ref-count
108 * drops to zero. In case a 'destructor' had been registered with the object,
109 * it will be called before freeing the memory.
110 */
111 void
112 sdb_object_deref(sdb_object_t *obj);
114 /*
115 * sdb_object_ref:
116 * Take ownership of the specified object, that is, increment the reference
117 * count by one.
118 */
119 void
120 sdb_object_ref(sdb_object_t *obj);
122 /*
123 * sdb_object_clone:
124 * Clone an existing object using its type's 'clone' callback. The callback is
125 * responsible for correctly initializing a new object (which may be done
126 * using the object create function or the object's type's init function).
127 *
128 * Returns:
129 * - the cloned object on success
130 * - NULL on error or if no clone callback is available
131 */
132 sdb_object_t *
133 sdb_object_clone(const sdb_object_t *obj);
135 #ifdef __cplusplus
136 } /* extern "C" */
137 #endif
139 #endif /* ! SDB_CORE_OBJECT_H */
141 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */