qdict.c revision 0fdfff3cce93e16179a454fd471cd1d9126204e0
1/*
2 * QDict Module
3 *
4 * Copyright (C) 2009 Red Hat Inc.
5 *
6 * Authors:
7 *  Luiz Capitulino <lcapitulino@redhat.com>
8 *
9 * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
10 * See the COPYING.LIB file in the top-level directory.
11 */
12
13#include "qapi/qmp/qint.h"
14#include "qapi/qmp/qfloat.h"
15#include "qapi/qmp/qdict.h"
16#include "qapi/qmp/qbool.h"
17#include "qapi/qmp/qstring.h"
18#include "qapi/qmp/qobject.h"
19#include "qemu-queue.h"
20#include "qemu-common.h"
21
22static void qdict_destroy_obj(QObject *obj);
23
24static const QType qdict_type = {
25    .code = QTYPE_QDICT,
26    .destroy = qdict_destroy_obj,
27};
28
29/**
30 * qdict_new(): Create a new QDict
31 *
32 * Return strong reference.
33 */
34QDict *qdict_new(void)
35{
36    QDict *qdict;
37
38    qdict = qemu_mallocz(sizeof(*qdict));
39    QOBJECT_INIT(qdict, &qdict_type);
40
41    return qdict;
42}
43
44/**
45 * qobject_to_qdict(): Convert a QObject into a QDict
46 */
47QDict *qobject_to_qdict(const QObject *obj)
48{
49    if (qobject_type(obj) != QTYPE_QDICT)
50        return NULL;
51
52    return container_of(obj, QDict, base);
53}
54
55/**
56 * tdb_hash(): based on the hash agorithm from gdbm, via tdb
57 * (from module-init-tools)
58 */
59static unsigned int tdb_hash(const char *name)
60{
61    unsigned value;	/* Used to compute the hash value.  */
62    unsigned   i;	/* Used to cycle through random values. */
63
64    /* Set the initial value from the key size. */
65    for (value = 0x238F13AF * strlen(name), i=0; name[i]; i++)
66        value = (value + (((const unsigned char *)name)[i] << (i*5 % 24)));
67
68    return (1103515243 * value + 12345);
69}
70
71/**
72 * alloc_entry(): allocate a new QDictEntry
73 */
74static QDictEntry *alloc_entry(const char *key, QObject *value)
75{
76    QDictEntry *entry;
77
78    entry = qemu_mallocz(sizeof(*entry));
79    entry->key = qemu_strdup(key);
80    entry->value = value;
81
82    return entry;
83}
84
85/**
86 * qdict_entry_value(): Return qdict entry value
87 *
88 * Return weak reference.
89 */
90QObject *qdict_entry_value(const QDictEntry *entry)
91{
92    return entry->value;
93}
94
95/**
96 * qdict_entry_key(): Return qdict entry key
97 *
98 * Return a *pointer* to the string, it has to be duplicated before being
99 * stored.
100 */
101const char *qdict_entry_key(const QDictEntry *entry)
102{
103    return entry->key;
104}
105
106/**
107 * qdict_find(): List lookup function
108 */
109static QDictEntry *qdict_find(const QDict *qdict,
110                              const char *key, unsigned int bucket)
111{
112    QDictEntry *entry;
113
114    QLIST_FOREACH(entry, &qdict->table[bucket], next)
115        if (!strcmp(entry->key, key))
116            return entry;
117
118    return NULL;
119}
120
121/**
122 * qdict_put_obj(): Put a new QObject into the dictionary
123 *
124 * Insert the pair 'key:value' into 'qdict', if 'key' already exists
125 * its 'value' will be replaced.
126 *
127 * This is done by freeing the reference to the stored QObject and
128 * storing the new one in the same entry.
129 *
130 * NOTE: ownership of 'value' is transferred to the QDict
131 */
132void qdict_put_obj(QDict *qdict, const char *key, QObject *value)
133{
134    unsigned int bucket;
135    QDictEntry *entry;
136
137    bucket = tdb_hash(key) % QDICT_BUCKET_MAX;
138    entry = qdict_find(qdict, key, bucket);
139    if (entry) {
140        /* replace key's value */
141        qobject_decref(entry->value);
142        entry->value = value;
143    } else {
144        /* allocate a new entry */
145        entry = alloc_entry(key, value);
146        QLIST_INSERT_HEAD(&qdict->table[bucket], entry, next);
147        qdict->size++;
148    }
149}
150
151/**
152 * qdict_get(): Lookup for a given 'key'
153 *
154 * Return a weak reference to the QObject associated with 'key' if
155 * 'key' is present in the dictionary, NULL otherwise.
156 */
157QObject *qdict_get(const QDict *qdict, const char *key)
158{
159    QDictEntry *entry;
160
161    entry = qdict_find(qdict, key, tdb_hash(key) % QDICT_BUCKET_MAX);
162    return (entry == NULL ? NULL : entry->value);
163}
164
165/**
166 * qdict_haskey(): Check if 'key' exists
167 *
168 * Return 1 if 'key' exists in the dict, 0 otherwise
169 */
170int qdict_haskey(const QDict *qdict, const char *key)
171{
172    unsigned int bucket = tdb_hash(key) % QDICT_BUCKET_MAX;
173    return (qdict_find(qdict, key, bucket) == NULL ? 0 : 1);
174}
175
176/**
177 * qdict_size(): Return the size of the dictionary
178 */
179size_t qdict_size(const QDict *qdict)
180{
181    return qdict->size;
182}
183
184/**
185 * qdict_get_obj(): Get a QObject of a specific type
186 */
187static QObject *qdict_get_obj(const QDict *qdict, const char *key,
188                              qtype_code type)
189{
190    QObject *obj;
191
192    obj = qdict_get(qdict, key);
193    assert(obj != NULL);
194    assert(qobject_type(obj) == type);
195
196    return obj;
197}
198
199/**
200 * qdict_get_double(): Get an number mapped by 'key'
201 *
202 * This function assumes that 'key' exists and it stores a
203 * QFloat or QInt object.
204 *
205 * Return number mapped by 'key'.
206 */
207double qdict_get_double(const QDict *qdict, const char *key)
208{
209    QObject *obj = qdict_get(qdict, key);
210
211    assert(obj);
212    switch (qobject_type(obj)) {
213    case QTYPE_QFLOAT:
214        return qfloat_get_double(qobject_to_qfloat(obj));
215    case QTYPE_QINT:
216        return qint_get_int(qobject_to_qint(obj));
217    default:
218        abort();
219    }
220}
221
222/**
223 * qdict_get_int(): Get an integer mapped by 'key'
224 *
225 * This function assumes that 'key' exists and it stores a
226 * QInt object.
227 *
228 * Return integer mapped by 'key'.
229 */
230int64_t qdict_get_int(const QDict *qdict, const char *key)
231{
232    QObject *obj = qdict_get_obj(qdict, key, QTYPE_QINT);
233    return qint_get_int(qobject_to_qint(obj));
234}
235
236/**
237 * qdict_get_bool(): Get a bool mapped by 'key'
238 *
239 * This function assumes that 'key' exists and it stores a
240 * QBool object.
241 *
242 * Return bool mapped by 'key'.
243 */
244int qdict_get_bool(const QDict *qdict, const char *key)
245{
246    QObject *obj = qdict_get_obj(qdict, key, QTYPE_QBOOL);
247    return qbool_get_int(qobject_to_qbool(obj));
248}
249
250/**
251 * qdict_get_qlist(): Get the QList mapped by 'key'
252 *
253 * This function assumes that 'key' exists and it stores a
254 * QList object.
255 *
256 * Return QList mapped by 'key'.
257 */
258QList *qdict_get_qlist(const QDict *qdict, const char *key)
259{
260    return qobject_to_qlist(qdict_get_obj(qdict, key, QTYPE_QLIST));
261}
262
263/**
264 * qdict_get_qdict(): Get the QDict mapped by 'key'
265 *
266 * This function assumes that 'key' exists and it stores a
267 * QDict object.
268 *
269 * Return QDict mapped by 'key'.
270 */
271QDict *qdict_get_qdict(const QDict *qdict, const char *key)
272{
273    return qobject_to_qdict(qdict_get_obj(qdict, key, QTYPE_QDICT));
274}
275
276/**
277 * qdict_get_str(): Get a pointer to the stored string mapped
278 * by 'key'
279 *
280 * This function assumes that 'key' exists and it stores a
281 * QString object.
282 *
283 * Return pointer to the string mapped by 'key'.
284 */
285const char *qdict_get_str(const QDict *qdict, const char *key)
286{
287    QObject *obj = qdict_get_obj(qdict, key, QTYPE_QSTRING);
288    return qstring_get_str(qobject_to_qstring(obj));
289}
290
291/**
292 * qdict_get_try_int(): Try to get integer mapped by 'key'
293 *
294 * Return integer mapped by 'key', if it is not present in
295 * the dictionary or if the stored object is not of QInt type
296 * 'def_value' will be returned.
297 */
298int64_t qdict_get_try_int(const QDict *qdict, const char *key,
299                          int64_t def_value)
300{
301    QObject *obj;
302
303    obj = qdict_get(qdict, key);
304    if (!obj || qobject_type(obj) != QTYPE_QINT)
305        return def_value;
306
307    return qint_get_int(qobject_to_qint(obj));
308}
309
310/**
311 * qdict_get_try_bool(): Try to get a bool mapped by 'key'
312 *
313 * Return bool mapped by 'key', if it is not present in the
314 * dictionary or if the stored object is not of QBool type
315 * 'def_value' will be returned.
316 */
317int qdict_get_try_bool(const QDict *qdict, const char *key, int def_value)
318{
319    QObject *obj;
320
321    obj = qdict_get(qdict, key);
322    if (!obj || qobject_type(obj) != QTYPE_QBOOL)
323        return def_value;
324
325    return qbool_get_int(qobject_to_qbool(obj));
326}
327
328/**
329 * qdict_get_try_str(): Try to get a pointer to the stored string
330 * mapped by 'key'
331 *
332 * Return a pointer to the string mapped by 'key', if it is not present
333 * in the dictionary or if the stored object is not of QString type
334 * NULL will be returned.
335 */
336const char *qdict_get_try_str(const QDict *qdict, const char *key)
337{
338    QObject *obj;
339
340    obj = qdict_get(qdict, key);
341    if (!obj || qobject_type(obj) != QTYPE_QSTRING)
342        return NULL;
343
344    return qstring_get_str(qobject_to_qstring(obj));
345}
346
347/**
348 * qdict_iter(): Iterate over all the dictionary's stored values.
349 *
350 * This function allows the user to provide an iterator, which will be
351 * called for each stored value in the dictionary.
352 */
353void qdict_iter(const QDict *qdict,
354                void (*iter)(const char *key, QObject *obj, void *opaque),
355                void *opaque)
356{
357    int i;
358    QDictEntry *entry;
359
360    for (i = 0; i < QDICT_BUCKET_MAX; i++) {
361        QLIST_FOREACH(entry, &qdict->table[i], next)
362            iter(entry->key, entry->value, opaque);
363    }
364}
365
366static QDictEntry *qdict_next_entry(const QDict *qdict, int first_bucket)
367{
368    int i;
369
370    for (i = first_bucket; i < QDICT_BUCKET_MAX; i++) {
371        if (!QLIST_EMPTY(&qdict->table[i])) {
372            return QLIST_FIRST(&qdict->table[i]);
373        }
374    }
375
376    return NULL;
377}
378
379/**
380 * qdict_first(): Return first qdict entry for iteration.
381 */
382const QDictEntry *qdict_first(const QDict *qdict)
383{
384    return qdict_next_entry(qdict, 0);
385}
386
387/**
388 * qdict_next(): Return next qdict entry in an iteration.
389 */
390const QDictEntry *qdict_next(const QDict *qdict, const QDictEntry *entry)
391{
392    QDictEntry *ret;
393
394    ret = QLIST_NEXT(entry, next);
395    if (!ret) {
396        unsigned int bucket = tdb_hash(entry->key) % QDICT_BUCKET_MAX;
397        ret = qdict_next_entry(qdict, bucket + 1);
398    }
399
400    return ret;
401}
402
403/**
404 * qentry_destroy(): Free all the memory allocated by a QDictEntry
405 */
406static void qentry_destroy(QDictEntry *e)
407{
408    assert(e != NULL);
409    assert(e->key != NULL);
410    assert(e->value != NULL);
411
412    qobject_decref(e->value);
413    qemu_free(e->key);
414    qemu_free(e);
415}
416
417/**
418 * qdict_del(): Delete a 'key:value' pair from the dictionary
419 *
420 * This will destroy all data allocated by this entry.
421 */
422void qdict_del(QDict *qdict, const char *key)
423{
424    QDictEntry *entry;
425
426    entry = qdict_find(qdict, key, tdb_hash(key) % QDICT_BUCKET_MAX);
427    if (entry) {
428        QLIST_REMOVE(entry, next);
429        qentry_destroy(entry);
430        qdict->size--;
431    }
432}
433
434/**
435 * qdict_destroy_obj(): Free all the memory allocated by a QDict
436 */
437static void qdict_destroy_obj(QObject *obj)
438{
439    int i;
440    QDict *qdict;
441
442    assert(obj != NULL);
443    qdict = qobject_to_qdict(obj);
444
445    for (i = 0; i < QDICT_BUCKET_MAX; i++) {
446        QDictEntry *entry = QLIST_FIRST(&qdict->table[i]);
447        while (entry) {
448            QDictEntry *tmp = QLIST_NEXT(entry, next);
449            QLIST_REMOVE(entry, next);
450            qentry_destroy(entry);
451            entry = tmp;
452        }
453    }
454
455    qemu_free(qdict);
456}
457