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 }
59 typedef struct {
60 sdb_object_t super;
61 void *data;
62 void (*destructor)(void *);
63 } sdb_object_wrapper_t;
65 #define SDB_OBJ(obj) ((sdb_object_t *)(obj))
66 #define SDB_CONST_OBJ(obj) ((const sdb_object_t *)(obj))
67 #define SDB_OBJ_WRAPPER(obj) ((sdb_object_wrapper_t *)(obj))
68 #define SDB_CONST_OBJ_WRAPPER(obj) ((const sdb_object_wrapper_t *)(obj))
70 /*
71 * sdb_object_create:
72 * Allocates a new sdb_object_t of the specified 'type'. The object will be
73 * initialized to zero and then passed on to the 'init' function (if
74 * specified). If specified, the 'destroy' callback will be called, when the
75 * reference count drops to zero and before freeing the memory allocated by
76 * the object itself.
77 *
78 * The init function will be called with the remaining arguments passed to
79 * sdb_object_create. If the init function fails (returns a non-zero value),
80 * the object will be destructed and destroyed.
81 *
82 * The reference count of the new object will be 1.
83 *
84 * Returns:
85 * - the newly allocated object
86 * - NULL on error
87 */
88 sdb_object_t *
89 sdb_object_create(sdb_type_t type, ...);
91 /*
92 * sdb_object_create_wrapper:
93 * Create a new sdb_object_t wrapping some arbitrary other object.
94 *
95 * Creation and initialization of the wrapped object needs to happen outside
96 * of the SysDB object system.
97 */
98 sdb_object_t *
99 sdb_object_create_wrapper(void *data, void (*destructor)(void *));
101 #define SDB_OBJECT_WRAPPER_STATIC(obj, destructor) \
102 { SDB_OBJECT_INIT, (obj), (destructor) }
104 /*
105 * sdb_object_deref:
106 * Dereference the object and free the allocated memory in case the ref-count
107 * drops to zero. In case a 'destructor' had been registered with the object,
108 * it will be called before freeing the memory.
109 */
110 void
111 sdb_object_deref(sdb_object_t *obj);
113 /*
114 * sdb_object_ref:
115 * Take ownership of the specified object, that is, increment the reference
116 * count by one.
117 */
118 void
119 sdb_object_ref(sdb_object_t *obj);
121 /*
122 * sdb_object_clone:
123 * Clone an existing object using its type's 'clone' callback. The callback is
124 * responsible for correctly initializing a new object (which may be done
125 * using the object create function or the object's type's init function).
126 *
127 * Returns:
128 * - the cloned object on success
129 * - NULL on error or if no clone callback is available
130 */
131 sdb_object_t *
132 sdb_object_clone(const sdb_object_t *obj);
134 #ifdef __cplusplus
135 } /* extern "C" */
136 #endif
138 #endif /* ! SDB_CORE_OBJECT_H */
140 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */