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 #include "qobject-internal.h"
  20
  21 /**
  22  * qdict_new(): Create a new QDict
  23  *
  24  * Return strong reference.
  25  */
  26 QDict *qdict_new(void)
  27 {
  28     QDict *qdict;
  29
  30     qdict = g_malloc0(sizeof(*qdict));
  31     qobject_init(QOBJECT(qdict), QTYPE_QDICT);
  32
  33     return qdict;
  34 }
  35
  36 /**
  37  * tdb_hash(): based on the hash algorithm from gdbm, via tdb
  38  * (from module-init-tools)
  39  */
  40 static unsigned int tdb_hash(const char *name)
  41 {
  42     unsigned value;     /* Used to compute the hash value.  */
  43     unsigned   i;       /* Used to cycle through random values. */
  44
  45     /* Set the initial value from the key size. */
  46     for (value = 0x238F13AF * strlen(name), i=0; name[i]; i++)
  47         value = (value + (((const unsigned char *)name)[i] << (i*5 % 24)));
  48
  49     return (1103515243 * value + 12345);
  50 }
  51
  52 /**
  53  * alloc_entry(): allocate a new QDictEntry
  54  */
  55 static QDictEntry *alloc_entry(const char *key, QObject *value)
  56 {
  57     QDictEntry *entry;
  58
  59     entry = g_malloc0(sizeof(*entry));
  60     entry->key = g_strdup(key);
  61     entry->value = value;
  62
  63     return entry;
  64 }
  65
  66 /**
  67  * qdict_entry_value(): Return qdict entry value
  68  *
  69  * Return weak reference.
  70  */
  71 QObject *qdict_entry_value(const QDictEntry *entry)
  72 {
  73     return entry->value;
  74 }
  75
  76 /**
  77  * qdict_entry_key(): Return qdict entry key
  78  *
  79  * Return a *pointer* to the string, it has to be duplicated before being
  80  * stored.
  81  */
  82 const char *qdict_entry_key(const QDictEntry *entry)
  83 {
  84     return entry->key;
  85 }
  86
  87 /**
  88  * qdict_find(): List lookup function
  89  */
  90 static QDictEntry *qdict_find(const QDict *qdict,
  91                               const char *key, unsigned int bucket)
  92 {
  93     QDictEntry *entry;
  94
  95     QLIST_FOREACH(entry, &qdict->table[bucket], next)
  96         if (!strcmp(entry->key, key))
  97             return entry;
  98
  99     return NULL;
 100 }
 101
 102 /**
 103  * qdict_put_obj(): Put a new QObject into the dictionary
 104  *
 105  * Insert the pair 'key:value' into 'qdict', if 'key' already exists
 106  * its 'value' will be replaced.
 107  *
 108  * This is done by freeing the reference to the stored QObject and
 109  * storing the new one in the same entry.
 110  *
 111  * NOTE: ownership of 'value' is transferred to the QDict
 112  */
 113 void qdict_put_obj(QDict *qdict, const char *key, QObject *value)
 114 {
 115     unsigned int bucket;
 116     QDictEntry *entry;
 117
 118     bucket = tdb_hash(key) % QDICT_BUCKET_MAX;
 119     entry = qdict_find(qdict, key, bucket);
 120     if (entry) {
 121         /* replace key's value */
 122         qobject_unref(entry->value);
 123         entry->value = value;
 124     } else {
 125         /* allocate a new entry */
 126         entry = alloc_entry(key, value);
 127         QLIST_INSERT_HEAD(&qdict->table[bucket], entry, next);
 128         qdict->size++;
 129     }
 130 }
 131
 132 void qdict_put_int(QDict *qdict, const char *key, int64_t value)
 133 {
 134     qdict_put(qdict, key, qnum_from_int(value));
 135 }
 136
 137 void qdict_put_bool(QDict *qdict, const char *key, bool value)
 138 {
 139     qdict_put(qdict, key, qbool_from_bool(value));
 140 }
 141
 142 void qdict_put_str(QDict *qdict, const char *key, const char *value)
 143 {
 144     qdict_put(qdict, key, qstring_from_str(value));
 145 }
 146
 147 void qdict_put_null(QDict *qdict, const char *key)
 148 {
 149     qdict_put(qdict, key, qnull());
 150 }
 151
 152 /**
 153  * qdict_get(): Lookup for a given 'key'
 154  *
 155  * Return a weak reference to the QObject associated with 'key' if
 156  * 'key' is present in the dictionary, NULL otherwise.
 157  */
 158 QObject *qdict_get(const QDict *qdict, const char *key)
 159 {
 160     QDictEntry *entry;
 161
 162     entry = qdict_find(qdict, key, tdb_hash(key) % QDICT_BUCKET_MAX);
 163     return (entry == NULL ? NULL : entry->value);
 164 }
 165
 166 /**
 167  * qdict_haskey(): Check if 'key' exists
 168  *
 169  * Return 1 if 'key' exists in the dict, 0 otherwise
 170  */
 171 int qdict_haskey(const QDict *qdict, const char *key)
 172 {
 173     unsigned int bucket = tdb_hash(key) % QDICT_BUCKET_MAX;
 174     return (qdict_find(qdict, key, bucket) == NULL ? 0 : 1);
 175 }
 176
 177 /**
 178  * qdict_size(): Return the size of the dictionary
 179  */
 180 size_t qdict_size(const QDict *qdict)
 181 {
 182     return qdict->size;
 183 }
 184
 185 /**
 186  * qdict_get_double(): Get an number mapped by 'key'
 187  *
 188  * This function assumes that 'key' exists and it stores a QNum.
 189  *
 190  * Return number mapped by 'key'.
 191  */
 192 double qdict_get_double(const QDict *qdict, const char *key)
 193 {
 194     return qnum_get_double(qobject_to(QNum, qdict_get(qdict, key)));
 195 }
 196
 197 /**
 198  * qdict_get_int(): Get an integer mapped by 'key'
 199  *
 200  * This function assumes that 'key' exists and it stores a
 201  * QNum representable as int.
 202  *
 203  * Return integer mapped by 'key'.
 204  */
 205 int64_t qdict_get_int(const QDict *qdict, const char *key)
 206 {
 207     return qnum_get_int(qobject_to(QNum, qdict_get(qdict, key)));
 208 }
 209
 210 /**
 211  * qdict_get_bool(): Get a bool mapped by 'key'
 212  *
 213  * This function assumes that 'key' exists and it stores a
 214  * QBool object.
 215  *
 216  * Return bool mapped by 'key'.
 217  */
 218 bool qdict_get_bool(const QDict *qdict, const char *key)
 219 {
 220     return qbool_get_bool(qobject_to(QBool, qdict_get(qdict, key)));
 221 }
 222
 223 /**
 224  * qdict_get_qlist(): If @qdict maps @key to a QList, return it, else NULL.
 225  */
 226 QList *qdict_get_qlist(const QDict *qdict, const char *key)
 227 {
 228     return qobject_to(QList, qdict_get(qdict, key));
 229 }
 230
 231 /**
 232  * qdict_get_qdict(): If @qdict maps @key to a QDict, return it, else NULL.
 233  */
 234 QDict *qdict_get_qdict(const QDict *qdict, const char *key)
 235 {
 236     return qobject_to(QDict, qdict_get(qdict, key));
 237 }
 238
 239 /**
 240  * qdict_get_str(): Get a pointer to the stored string mapped
 241  * by 'key'
 242  *
 243  * This function assumes that 'key' exists and it stores a
 244  * QString object.
 245  *
 246  * Return pointer to the string mapped by 'key'.
 247  */
 248 const char *qdict_get_str(const QDict *qdict, const char *key)
 249 {
 250     return qstring_get_str(qobject_to(QString, qdict_get(qdict, key)));
 251 }
 252
 253 /**
 254  * qdict_get_try_int(): Try to get integer mapped by 'key'
 255  *
 256  * Return integer mapped by 'key', if it is not present in the
 257  * dictionary or if the stored object is not a QNum representing an
 258  * integer, 'def_value' will be returned.
 259  */
 260 int64_t qdict_get_try_int(const QDict *qdict, const char *key,
 261                           int64_t def_value)
 262 {
 263     QNum *qnum = qobject_to(QNum, qdict_get(qdict, key));
 264     int64_t val;
 265
 266     if (!qnum || !qnum_get_try_int(qnum, &val)) {
 267         return def_value;
 268     }
 269
 270     return val;
 271 }
 272
 273 /**
 274  * qdict_get_try_bool(): Try to get a bool mapped by 'key'
 275  *
 276  * Return bool mapped by 'key', if it is not present in the
 277  * dictionary or if the stored object is not of QBool type
 278  * 'def_value' will be returned.
 279  */
 280 bool qdict_get_try_bool(const QDict *qdict, const char *key, bool def_value)
 281 {
 282     QBool *qbool = qobject_to(QBool, qdict_get(qdict, key));
 283
 284     return qbool ? qbool_get_bool(qbool) : def_value;
 285 }
 286
 287 /**
 288  * qdict_get_try_str(): Try to get a pointer to the stored string
 289  * mapped by 'key'
 290  *
 291  * Return a pointer to the string mapped by 'key', if it is not present
 292  * in the dictionary or if the stored object is not of QString type
 293  * NULL will be returned.
 294  */
 295 const char *qdict_get_try_str(const QDict *qdict, const char *key)
 296 {
 297     QString *qstr = qobject_to(QString, qdict_get(qdict, key));
 298
 299     return qstr ? qstring_get_str(qstr) : NULL;
 300 }
 301
 302 static QDictEntry *qdict_next_entry(const QDict *qdict, int first_bucket)
 303 {
 304     int i;
 305
 306     for (i = first_bucket; i < QDICT_BUCKET_MAX; i++) {
 307         if (!QLIST_EMPTY(&qdict->table[i])) {
 308             return QLIST_FIRST(&qdict->table[i]);
 309         }
 310     }
 311
 312     return NULL;
 313 }
 314
 315 /**
 316  * qdict_first(): Return first qdict entry for iteration.
 317  */
 318 const QDictEntry *qdict_first(const QDict *qdict)
 319 {
 320     return qdict_next_entry(qdict, 0);
 321 }
 322
 323 /**
 324  * qdict_next(): Return next qdict entry in an iteration.
 325  */
 326 const QDictEntry *qdict_next(const QDict *qdict, const QDictEntry *entry)
 327 {
 328     QDictEntry *ret;
 329
 330     ret = QLIST_NEXT(entry, next);
 331     if (!ret) {
 332         unsigned int bucket = tdb_hash(entry->key) % QDICT_BUCKET_MAX;
 333         ret = qdict_next_entry(qdict, bucket + 1);
 334     }
 335
 336     return ret;
 337 }
 338
 339 /**
 340  * qdict_clone_shallow(): Clones a given QDict. Its entries are not copied, but
 341  * another reference is added.
 342  */
 343 QDict *qdict_clone_shallow(const QDict *src)
 344 {
 345     QDict *dest;
 346     QDictEntry *entry;
 347     int i;
 348
 349     dest = qdict_new();
 350
 351     for (i = 0; i < QDICT_BUCKET_MAX; i++) {
 352         QLIST_FOREACH(entry, &src->table[i], next) {
 353             qdict_put_obj(dest, entry->key, qobject_ref(entry->value));
 354         }
 355     }
 356
 357     return dest;
 358 }
 359
 360 /**
 361  * qentry_destroy(): Free all the memory allocated by a QDictEntry
 362  */
 363 static void qentry_destroy(QDictEntry *e)
 364 {
 365     assert(e != NULL);
 366     assert(e->key != NULL);
 367     assert(e->value != NULL);
 368
 369     qobject_unref(e->value);
 370     g_free(e->key);
 371     g_free(e);
 372 }
 373
 374 /**
 375  * qdict_del(): Delete a 'key:value' pair from the dictionary
 376  *
 377  * This will destroy all data allocated by this entry.
 378  */
 379 void qdict_del(QDict *qdict, const char *key)
 380 {
 381     QDictEntry *entry;
 382
 383     entry = qdict_find(qdict, key, tdb_hash(key) % QDICT_BUCKET_MAX);
 384     if (entry) {
 385         QLIST_REMOVE(entry, next);
 386         qentry_destroy(entry);
 387         qdict->size--;
 388     }
 389 }
 390
 391 /**
 392  * qdict_is_equal(): Test whether the two QDicts are equal
 393  *
 394  * Here, equality means whether they contain the same keys and whether
 395  * the respective values are in turn equal (i.e. invoking
 396  * qobject_is_equal() on them yields true).
 397  */
 398 bool qdict_is_equal(const QObject *x, const QObject *y)
 399 {
 400     const QDict *dict_x = qobject_to(QDict, x);
 401     const QDict *dict_y = qobject_to(QDict, y);
 402     const QDictEntry *e;
 403
 404     if (qdict_size(dict_x) != qdict_size(dict_y)) {
 405         return false;
 406     }
 407
 408     for (e = qdict_first(dict_x); e; e = qdict_next(dict_x, e)) {
 409         const QObject *obj_x = qdict_entry_value(e);
 410         const QObject *obj_y = qdict_get(dict_y, qdict_entry_key(e));
 411
 412         if (!qobject_is_equal(obj_x, obj_y)) {
 413             return false;
 414         }
 415     }
 416
 417     return true;
 418 }
 419
 420 /**
 421  * qdict_destroy_obj(): Free all the memory allocated by a QDict
 422  */
 423 void qdict_destroy_obj(QObject *obj)
 424 {
 425     int i;
 426     QDict *qdict;
 427
 428     assert(obj != NULL);
 429     qdict = qobject_to(QDict, obj);
 430
 431     for (i = 0; i < QDICT_BUCKET_MAX; i++) {
 432         QDictEntry *entry = QLIST_FIRST(&qdict->table[i]);
 433         while (entry) {
 434             QDictEntry *tmp = QLIST_NEXT(entry, next);
 435             QLIST_REMOVE(entry, next);
 436             qentry_destroy(entry);
 437             entry = tmp;
 438         }
 439     }
 440
 441     g_free(qdict);
 442 }