Root/package/libnl-tiny/src/object.c

1/*
2 * lib/object.c Generic Cacheable Object
3 *
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation version 2.1
7 * of the License.
8 *
9 * Copyright (c) 2003-2008 Thomas Graf <tgraf@suug.ch>
10 */
11
12/**
13 * @ingroup cache
14 * @defgroup object Object
15 * @{
16 */
17
18#include <netlink-local.h>
19#include <netlink/netlink.h>
20#include <netlink/cache.h>
21#include <netlink/object.h>
22#include <netlink/utils.h>
23
24static inline struct nl_object_ops *obj_ops(struct nl_object *obj)
25{
26    if (!obj->ce_ops)
27        BUG();
28
29    return obj->ce_ops;
30}
31
32/**
33 * @name Object Creation/Deletion
34 * @{
35 */
36
37/**
38 * Allocate a new object of kind specified by the operations handle
39 * @arg ops cache operations handle
40 * @return The new object or NULL
41 */
42struct nl_object *nl_object_alloc(struct nl_object_ops *ops)
43{
44    struct nl_object *new;
45
46    if (ops->oo_size < sizeof(*new))
47        BUG();
48
49    new = calloc(1, ops->oo_size);
50    if (!new)
51        return NULL;
52
53    new->ce_refcnt = 1;
54    nl_init_list_head(&new->ce_list);
55
56    new->ce_ops = ops;
57    if (ops->oo_constructor)
58        ops->oo_constructor(new);
59
60    NL_DBG(4, "Allocated new object %p\n", new);
61
62    return new;
63}
64
65#ifdef disabled
66/**
67 * Allocate a new object of kind specified by the name
68 * @arg kind name of object type
69 * @return The new object or nULL
70 */
71int nl_object_alloc_name(const char *kind, struct nl_object **result)
72{
73    struct nl_cache_ops *ops;
74
75    ops = nl_cache_ops_lookup(kind);
76    if (!ops)
77        return -NLE_OPNOTSUPP;
78
79    if (!(*result = nl_object_alloc(ops->co_obj_ops)))
80        return -NLE_NOMEM;
81
82    return 0;
83}
84#endif
85
86struct nl_derived_object {
87    NLHDR_COMMON
88    char data;
89};
90
91/**
92 * Allocate a new object and copy all data from an existing object
93 * @arg obj object to inherite data from
94 * @return The new object or NULL.
95 */
96struct nl_object *nl_object_clone(struct nl_object *obj)
97{
98    struct nl_object *new;
99    struct nl_object_ops *ops = obj_ops(obj);
100    int doff = offsetof(struct nl_derived_object, data);
101    int size;
102
103    new = nl_object_alloc(ops);
104    if (!new)
105        return NULL;
106
107    size = ops->oo_size - doff;
108    if (size < 0)
109        BUG();
110
111    new->ce_ops = obj->ce_ops;
112    new->ce_msgtype = obj->ce_msgtype;
113
114    if (size)
115        memcpy((void *)new + doff, (void *)obj + doff, size);
116
117    if (ops->oo_clone) {
118        if (ops->oo_clone(new, obj) < 0) {
119            nl_object_free(new);
120            return NULL;
121        }
122    } else if (size && ops->oo_free_data)
123        BUG();
124
125    return new;
126}
127
128/**
129 * Free a cacheable object
130 * @arg obj object to free
131 *
132 * @return 0 or a negative error code.
133 */
134void nl_object_free(struct nl_object *obj)
135{
136    struct nl_object_ops *ops = obj_ops(obj);
137
138    if (obj->ce_refcnt > 0)
139        NL_DBG(1, "Warning: Freeing object in use...\n");
140
141    if (obj->ce_cache)
142        nl_cache_remove(obj);
143
144    if (ops->oo_free_data)
145        ops->oo_free_data(obj);
146
147    free(obj);
148
149    NL_DBG(4, "Freed object %p\n", obj);
150}
151
152/** @} */
153
154/**
155 * @name Reference Management
156 * @{
157 */
158
159/**
160 * Acquire a reference on a object
161 * @arg obj object to acquire reference from
162 */
163void nl_object_get(struct nl_object *obj)
164{
165    obj->ce_refcnt++;
166    NL_DBG(4, "New reference to object %p, total %d\n",
167           obj, obj->ce_refcnt);
168}
169
170/**
171 * Release a reference from an object
172 * @arg obj object to release reference from
173 */
174void nl_object_put(struct nl_object *obj)
175{
176    if (!obj)
177        return;
178
179    obj->ce_refcnt--;
180    NL_DBG(4, "Returned object reference %p, %d remaining\n",
181           obj, obj->ce_refcnt);
182
183    if (obj->ce_refcnt < 0)
184        BUG();
185
186    if (obj->ce_refcnt <= 0)
187        nl_object_free(obj);
188}
189
190/** @} */
191
192/**
193 * @name Utillities
194 * @{
195 */
196
197#ifdef disabled
198/**
199 * Dump this object according to the specified parameters
200 * @arg obj object to dump
201 * @arg params dumping parameters
202 */
203void nl_object_dump(struct nl_object *obj, struct nl_dump_params *params)
204{
205    dump_from_ops(obj, params);
206}
207
208/**
209 * Check if the identifiers of two objects are identical
210 * @arg a an object
211 * @arg b another object of same type
212 *
213 * @return true if both objects have equal identifiers, otherwise false.
214 */
215int nl_object_identical(struct nl_object *a, struct nl_object *b)
216{
217    struct nl_object_ops *ops = obj_ops(a);
218    int req_attrs;
219
220    /* Both objects must be of same type */
221    if (ops != obj_ops(b))
222        return 0;
223
224    req_attrs = ops->oo_id_attrs;
225
226    /* Both objects must provide all required attributes to uniquely
227     * identify an object */
228    if ((a->ce_mask & req_attrs) != req_attrs ||
229        (b->ce_mask & req_attrs) != req_attrs)
230        return 0;
231
232    /* Can't judge unless we can compare */
233    if (ops->oo_compare == NULL)
234        return 0;
235
236    return !(ops->oo_compare(a, b, req_attrs, 0));
237}
238#endif
239
240/**
241 * Compute bitmask representing difference in attribute values
242 * @arg a an object
243 * @arg b another object of same type
244 *
245 * The bitmask returned is specific to an object type, each bit set represents
246 * an attribute which mismatches in either of the two objects. Unavailability
247 * of an attribute in one object and presence in the other is regarded a
248 * mismatch as well.
249 *
250 * @return Bitmask describing differences or 0 if they are completely identical.
251 */
252uint32_t nl_object_diff(struct nl_object *a, struct nl_object *b)
253{
254    struct nl_object_ops *ops = obj_ops(a);
255
256    if (ops != obj_ops(b) || ops->oo_compare == NULL)
257        return UINT_MAX;
258
259    return ops->oo_compare(a, b, ~0, 0);
260}
261
262/**
263 * Match a filter against an object
264 * @arg obj object to check
265 * @arg filter object of same type acting as filter
266 *
267 * @return 1 if the object matches the filter or 0
268 * if no filter procedure is available or if the
269 * filter does not match.
270 */
271int nl_object_match_filter(struct nl_object *obj, struct nl_object *filter)
272{
273    struct nl_object_ops *ops = obj_ops(obj);
274
275    if (ops != obj_ops(filter) || ops->oo_compare == NULL)
276        return 0;
277    
278    return !(ops->oo_compare(obj, filter, filter->ce_mask,
279                 LOOSE_COMPARISON));
280}
281
282/**
283 * Convert bitmask of attributes to a character string
284 * @arg obj object of same type as attribute bitmask
285 * @arg attrs bitmask of attribute types
286 * @arg buf destination buffer
287 * @arg len length of destination buffer
288 *
289 * Converts the bitmask of attribute types into a list of attribute
290 * names separated by comas.
291 *
292 * @return destination buffer.
293 */
294char *nl_object_attrs2str(struct nl_object *obj, uint32_t attrs,
295              char *buf, size_t len)
296{
297    struct nl_object_ops *ops = obj_ops(obj);
298
299    if (ops->oo_attrs2str != NULL)
300        return ops->oo_attrs2str(attrs, buf, len);
301    else {
302        memset(buf, 0, len);
303        return buf;
304    }
305}
306
307/** @} */
308
309/** @} */
310

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