qobject/qdict.c

   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 "qemu/osdep.h"
  14 #include "qapi/qmp/qnum.h"
  15 #include "qapi/qmp/qdict.h"
  16 #include "qapi/qmp/qbool.h"
  17 #include "qapi/qmp/qnull.h"
  18 #include "qapi/qmp/qstring.h"
  19
  20 /**
  21  * qdict_new(): Create a new QDict
  22  *
  23  * Return strong reference.
  24  */
  25 QDict *qdict_new(void)
  26 {
  27     QDict *qdict;
  28
  29     qdict = g_malloc0(sizeof(*qdict));
  30     qobject_init(QOBJECT(qdict), QTYPE_QDICT);
  31
  32     return qdict;
  33 }
  34
  35 /**
  36  * tdb_hash(): based on the hash algorithm from gdbm, via tdb
  37  * (from module-init-tools)
  38  */
  39 static unsigned int tdb_hash(const char *name)
  40 {
  41     unsigned value;     /* Used to compute the hash value.  */
  42     unsigned   i;       /* Used to cycle through random values. */
  43
  44     /* Set the initial value from the key size. */
  45     for (value = 0x238F13AF * strlen(name), i=0; name[i]; i++)
  46         value = (value + (((const unsigned char *)name)[i] << (i*5 % 24)));
  47
  48     return (1103515243 * value + 12345);
  49 }
  50
  51 /**
  52  * alloc_entry(): allocate a new QDictEntry
  53  */
  54 static QDictEntry *alloc_entry(const char *key, QObject *value)
  55 {
  56     QDictEntry *entry;
  57
  58     entry = g_malloc0(sizeof(*entry));
  59     entry->key = g_strdup(key);
  60     entry->value = value;
  61
  62     return entry;
  63 }
  64
  65 /**
  66  * qdict_entry_value(): Return qdict entry value
  67  *
  68  * Return weak reference.
  69  */
  70 QObject *qdict_entry_value(const QDictEntry *entry)
  71 {
  72     return entry->value;
  73 }
  74
  75 /**
  76  * qdict_entry_key(): Return qdict entry key
  77  *
  78  * Return a *pointer* to the string, it has to be duplicated before being
  79  * stored.
  80  */
  81 const char *qdict_entry_key(const QDictEntry *entry)
  82 {
  83     return entry->key;
  84 }
  85
  86 /**
  87  * qdict_find(): List lookup function
  88  */
  89 static QDictEntry *qdict_find(const QDict *qdict,
  90                               const char *key, unsigned int bucket)
  91 {
  92     QDictEntry *entry;
  93
  94     QLIST_FOREACH(entry, &qdict->table[bucket], next)
  95         if (!strcmp(entry->key, key))
  96             return entry;
  97
  98     return NULL;
  99 }
 100
 101 /**
 102  * qdict_put_obj(): Put a new QObject into the dictionary
 103  *
 104  * Insert the pair 'key:value' into 'qdict', if 'key' already exists
 105  * its 'value' will be replaced.
 106  *
 107  * This is done by freeing the reference to the stored QObject and
 108  * storing the new one in the same entry.
 109  *
 110  * NOTE: ownership of 'value' is transferred to the QDict
 111  */
 112 void qdict_put_obj(QDict *qdict, const char *key, QObject *value)
 113 {
 114     unsigned int bucket;
 115     QDictEntry *entry;
 116
 117     bucket = tdb_hash(key) % QDICT_BUCKET_MAX;
 118     entry = qdict_find(qdict, key, bucket);
 119     if (entry) {
 120         /* replace key's value */
 121         qobject_unref(entry->value);
 122         entry->value = value;
 123     } else {
 124         /* allocate a new entry */
 125         entry = alloc_entry(key, value);
 126         QLIST_INSERT_HEAD(&qdict->table[bucket], entry, next);
 127         qdict->size++;
 128     }
 129 }
 130
 131 void qdict_put_int(QDict *qdict, const char *key, int64_t value)
 132 {
 133     qdict_put(qdict, key, qnum_from_int(value));
 134 }
 135
 136 void qdict_put_bool(QDict *qdict, const char *key, bool value)
 137 {
 138     qdict_put(qdict, key, qbool_from_bool(value));
 139 }
 140
 141 void qdict_put_str(QDict *qdict, const char *key, const char *value)
 142 {
 143     qdict_put(qdict, key, qstring_from_str(value));
 144 }
 145
 146 void qdict_put_null(QDict *qdict, const char *key)
 147 {
 148     qdict_put(qdict, key, qnull());
 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  */
 157 QObject *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  */
 170 int 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  */
 179 size_t qdict_size(const QDict *qdict)
 180 {
 181     return qdict->size;
 182 }
 183
 184 /**
 185  * qdict_get_double(): Get an number mapped by 'key'
 186  *
 187  * This function assumes that 'key' exists and it stores a QNum.
 188  *
 189  * Return number mapped by 'key'.
 190  */
 191 double qdict_get_double(const QDict *qdict, const char *key)
 192 {
 193     return qnum_get_double(qobject_to(QNum, qdict_get(qdict, key)));
 194 }
 195
 196 /**
 197  * qdict_get_int(): Get an integer mapped by 'key'
 198  *
 199  * This function assumes that 'key' exists and it stores a
 200  * QNum representable as int.
 201  *
 202  * Return integer mapped by 'key'.
 203  */
 204 int64_t qdict_get_int(const QDict *qdict, const char *key)
 205 {
 206     return qnum_get_int(qobject_to(QNum, qdict_get(qdict, key)));
 207 }
 208
 209 /**
 210  * qdict_get_bool(): Get a bool mapped by 'key'
 211  *
 212  * This function assumes that 'key' exists and it stores a
 213  * QBool object.
 214  *
 215  * Return bool mapped by 'key'.
 216  */
 217 bool qdict_get_bool(const QDict *qdict, const char *key)
 218 {
 219     return qbool_get_bool(qobject_to(QBool, qdict_get(qdict, key)));
 220 }
 221
 222 /**
 223  * qdict_get_qlist(): If @qdict maps @key to a QList, return it, else NULL.
 224  */
 225 QList *qdict_get_qlist(const QDict *qdict, const char *key)
 226 {
 227     return qobject_to(QList, qdict_get(qdict, key));
 228 }
 229
 230 /**
 231  * qdict_get_qdict(): If @qdict maps @key to a QDict, return it, else NULL.
 232  */
 233 QDict *qdict_get_qdict(const QDict *qdict, const char *key)
 234 {
 235     return qobject_to(QDict, qdict_get(qdict, key));
 236 }
 237
 238 /**
 239  * qdict_get_str(): Get a pointer to the stored string mapped
 240  * by 'key'
 241  *
 242  * This function assumes that 'key' exists and it stores a
 243  * QString object.
 244  *
 245  * Return pointer to the string mapped by 'key'.
 246  */
 247 const char *qdict_get_str(const QDict *qdict, const char *key)
 248 {
 249     return qstring_get_str(qobject_to(QString, qdict_get(qdict, key)));
 250 }
 251
 252 /**
 253  * qdict_get_try_int(): Try to get integer mapped by 'key'
 254  *
 255  * Return integer mapped by 'key', if it is not present in the
 256  * dictionary or if the stored object is not a QNum representing an
 257  * integer, 'def_value' will be returned.
 258  */
 259 int64_t qdict_get_try_int(const QDict *qdict, const char *key,
 260                           int64_t def_value)
 261 {
 262     QNum *qnum = qobject_to(QNum, qdict_get(qdict, key));
 263     int64_t val;
 264
 265     if (!qnum || !qnum_get_try_int(qnum, &val)) {
 266         return def_value;
 267     }
 268
 269     return val;
 270 }
 271
 272 /**
 273  * qdict_get_try_bool(): Try to get a bool mapped by 'key'
 274  *
 275  * Return bool mapped by 'key', if it is not present in the
 276  * dictionary or if the stored object is not of QBool type
 277  * 'def_value' will be returned.
 278  */
 279 bool qdict_get_try_bool(const QDict *qdict, const char *key, bool def_value)
 280 {
 281     QBool *qbool = qobject_to(QBool, qdict_get(qdict, key));
 282
 283     return qbool ? qbool_get_bool(qbool) : def_value;
 284 }
 285
 286 /**
 287  * qdict_get_try_str(): Try to get a pointer to the stored string
 288  * mapped by 'key'
 289  *
 290  * Return a pointer to the string mapped by 'key', if it is not present
 291  * in the dictionary or if the stored object is not of QString type
 292  * NULL will be returned.
 293  */
 294 const char *qdict_get_try_str(const QDict *qdict, const char *key)
 295 {
 296     QString *qstr = qobject_to(QString, qdict_get(qdict, key));
 297
 298     return qstr ? qstring_get_str(qstr) : NULL;
 299 }
 300
 301 static QDictEntry *qdict_next_entry(const QDict *qdict, int first_bucket)
 302 {
 303     int i;
 304
 305     for (i = first_bucket; i < QDICT_BUCKET_MAX; i++) {
 306         if (!QLIST_EMPTY(&qdict->table[i])) {
 307             return QLIST_FIRST(&qdict->table[i]);
 308         }
 309     }
 310
 311     return NULL;
 312 }
 313
 314 /**
 315  * qdict_first(): Return first qdict entry for iteration.
 316  */
 317 const QDictEntry *qdict_first(const QDict *qdict)
 318 {
 319     return qdict_next_entry(qdict, 0);
 320 }
 321
 322 /**
 323  * qdict_next(): Return next qdict entry in an iteration.
 324  */
 325 const QDictEntry *qdict_next(const QDict *qdict, const QDictEntry *entry)
 326 {
 327     QDictEntry *ret;
 328
 329     ret = QLIST_NEXT(entry, next);
 330     if (!ret) {
 331         unsigned int bucket = tdb_hash(entry->key) % QDICT_BUCKET_MAX;
 332         ret = qdict_next_entry(qdict, bucket + 1);
 333     }
 334
 335     return ret;
 336 }
 337
 338 /**
 339  * qdict_clone_shallow(): Clones a given QDict. Its entries are not copied, but
 340  * another reference is added.
 341  */
 342 QDict *qdict_clone_shallow(const QDict *src)
 343 {
 344     QDict *dest;
 345     QDictEntry *entry;
 346     int i;
 347
 348     dest = qdict_new();
 349
 350     for (i = 0; i < QDICT_BUCKET_MAX; i++) {
 351         QLIST_FOREACH(entry, &src->table[i], next) {
 352             qdict_put_obj(dest, entry->key, qobject_ref(entry->value));
 353         }
 354     }
 355
 356     return dest;
 357 }
 358
 359 /**
 360  * qentry_destroy(): Free all the memory allocated by a QDictEntry
 361  */
 362 static void qentry_destroy(QDictEntry *e)
 363 {
 364     assert(e != NULL);
 365     assert(e->key != NULL);
 366     assert(e->value != NULL);
 367
 368     qobject_unref(e->value);
 369     g_free(e->key);
 370     g_free(e);
 371 }
 372
 373 /**
 374  * qdict_del(): Delete a 'key:value' pair from the dictionary
 375  *
 376  * This will destroy all data allocated by this entry.
 377  */
 378 void qdict_del(QDict *qdict, const char *key)
 379 {
 380     QDictEntry *entry;
 381
 382     entry = qdict_find(qdict, key, tdb_hash(key) % QDICT_BUCKET_MAX);
 383     if (entry) {
 384         QLIST_REMOVE(entry, next);
 385         qentry_destroy(entry);
 386         qdict->size--;
 387     }
 388 }
 389
 390 /**
 391  * qdict_is_equal(): Test whether the two QDicts are equal
 392  *
 393  * Here, equality means whether they contain the same keys and whether
 394  * the respective values are in turn equal (i.e. invoking
 395  * qobject_is_equal() on them yields true).
 396  */
 397 bool qdict_is_equal(const QObject *x, const QObject *y)
 398 {
 399     const QDict *dict_x = qobject_to(QDict, x);
 400     const QDict *dict_y = qobject_to(QDict, y);
 401     const QDictEntry *e;
 402
 403     if (qdict_size(dict_x) != qdict_size(dict_y)) {
 404         return false;
 405     }
 406
 407     for (e = qdict_first(dict_x); e; e = qdict_next(dict_x, e)) {
 408         const QObject *obj_x = qdict_entry_value(e);
 409         const QObject *obj_y = qdict_get(dict_y, qdict_entry_key(e));
 410
 411         if (!qobject_is_equal(obj_x, obj_y)) {
 412             return false;
 413         }
 414     }
 415
 416     return true;
 417 }
 418
 419 /**
 420  * qdict_destroy_obj(): Free all the memory allocated by a QDict
 421  */
 422 void qdict_destroy_obj(QObject *obj)
 423 {
 424     int i;
 425     QDict *qdict;
 426
 427     assert(obj != NULL);
 428     qdict = qobject_to(QDict, obj);
 429
 430     for (i = 0; i < QDICT_BUCKET_MAX; i++) {
 431         QDictEntry *entry = QLIST_FIRST(&qdict->table[i]);
 432         while (entry) {
 433             QDictEntry *tmp = QLIST_NEXT(entry, next);
 434             QLIST_REMOVE(entry, next);
 435             qentry_destroy(entry);
 436             entry = tmp;
 437         }
 438     }
 439
 440     g_free(qdict);
 441 }