qemu/qobject/qdict.c
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   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 */
  26QDict *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 */
  40static 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
  50    return (1103515243 * value + 12345);
  51}
  52
  53/**
  54 * alloc_entry(): allocate a new QDictEntry
  55 */
  56static QDictEntry *alloc_entry(const char *key, QObject *value)
  57{
  58    QDictEntry *entry;
  59
  60    entry = g_malloc0(sizeof(*entry));
  61    entry->key = g_strdup(key);
  62    entry->value = value;
  63
  64    return entry;
  65}
  66
  67/**
  68 * qdict_entry_value(): Return qdict entry value
  69 *
  70 * Return weak reference.
  71 */
  72QObject *qdict_entry_value(const QDictEntry *entry)
  73{
  74    return entry->value;
  75}
  76
  77/**
  78 * qdict_entry_key(): Return qdict entry key
  79 *
  80 * Return a *pointer* to the string, it has to be duplicated before being
  81 * stored.
  82 */
  83const char *qdict_entry_key(const QDictEntry *entry)
  84{
  85    return entry->key;
  86}
  87
  88/**
  89 * qdict_find(): List lookup function
  90 */
  91static QDictEntry *qdict_find(const QDict *qdict,
  92                              const char *key, unsigned int bucket)
  93{
  94    QDictEntry *entry;
  95
  96    QLIST_FOREACH(entry, &qdict->table[bucket], next)
  97        if (!strcmp(entry->key, key)) {
  98            return entry;
  99        }
 100
 101    return NULL;
 102}
 103
 104/**
 105 * qdict_put_obj(): Put a new QObject into the dictionary
 106 *
 107 * Insert the pair 'key:value' into 'qdict', if 'key' already exists
 108 * its 'value' will be replaced.
 109 *
 110 * This is done by freeing the reference to the stored QObject and
 111 * storing the new one in the same entry.
 112 *
 113 * NOTE: ownership of 'value' is transferred to the QDict
 114 */
 115void qdict_put_obj(QDict *qdict, const char *key, QObject *value)
 116{
 117    unsigned int bucket;
 118    QDictEntry *entry;
 119
 120    bucket = tdb_hash(key) % QDICT_BUCKET_MAX;
 121    entry = qdict_find(qdict, key, bucket);
 122    if (entry) {
 123        /* replace key's value */
 124        qobject_unref(entry->value);
 125        entry->value = value;
 126    } else {
 127        /* allocate a new entry */
 128        entry = alloc_entry(key, value);
 129        QLIST_INSERT_HEAD(&qdict->table[bucket], entry, next);
 130        qdict->size++;
 131    }
 132}
 133
 134void qdict_put_int(QDict *qdict, const char *key, int64_t value)
 135{
 136    qdict_put(qdict, key, qnum_from_int(value));
 137}
 138
 139void qdict_put_bool(QDict *qdict, const char *key, bool value)
 140{
 141    qdict_put(qdict, key, qbool_from_bool(value));
 142}
 143
 144void qdict_put_str(QDict *qdict, const char *key, const char *value)
 145{
 146    qdict_put(qdict, key, qstring_from_str(value));
 147}
 148
 149void qdict_put_null(QDict *qdict, const char *key)
 150{
 151    qdict_put(qdict, key, qnull());
 152}
 153
 154/**
 155 * qdict_get(): Lookup for a given 'key'
 156 *
 157 * Return a weak reference to the QObject associated with 'key' if
 158 * 'key' is present in the dictionary, NULL otherwise.
 159 */
 160QObject *qdict_get(const QDict *qdict, const char *key)
 161{
 162    QDictEntry *entry;
 163
 164    entry = qdict_find(qdict, key, tdb_hash(key) % QDICT_BUCKET_MAX);
 165    return (entry == NULL ? NULL : entry->value);
 166}
 167
 168/**
 169 * qdict_haskey(): Check if 'key' exists
 170 *
 171 * Return 1 if 'key' exists in the dict, 0 otherwise
 172 */
 173int qdict_haskey(const QDict *qdict, const char *key)
 174{
 175    unsigned int bucket = tdb_hash(key) % QDICT_BUCKET_MAX;
 176    return (qdict_find(qdict, key, bucket) == NULL ? 0 : 1);
 177}
 178
 179/**
 180 * qdict_size(): Return the size of the dictionary
 181 */
 182size_t qdict_size(const QDict *qdict)
 183{
 184    return qdict->size;
 185}
 186
 187/**
 188 * qdict_get_double(): Get an number mapped by 'key'
 189 *
 190 * This function assumes that 'key' exists and it stores a QNum.
 191 *
 192 * Return number mapped by 'key'.
 193 */
 194double qdict_get_double(const QDict *qdict, const char *key)
 195{
 196    return qnum_get_double(qobject_to(QNum, qdict_get(qdict, key)));
 197}
 198
 199/**
 200 * qdict_get_int(): Get an integer mapped by 'key'
 201 *
 202 * This function assumes that 'key' exists and it stores a
 203 * QNum representable as int.
 204 *
 205 * Return integer mapped by 'key'.
 206 */
 207int64_t qdict_get_int(const QDict *qdict, const char *key)
 208{
 209    return qnum_get_int(qobject_to(QNum, qdict_get(qdict, key)));
 210}
 211
 212/**
 213 * qdict_get_bool(): Get a bool mapped by 'key'
 214 *
 215 * This function assumes that 'key' exists and it stores a
 216 * QBool object.
 217 *
 218 * Return bool mapped by 'key'.
 219 */
 220bool qdict_get_bool(const QDict *qdict, const char *key)
 221{
 222    return qbool_get_bool(qobject_to(QBool, qdict_get(qdict, key)));
 223}
 224
 225/**
 226 * qdict_get_qlist(): If @qdict maps @key to a QList, return it, else NULL.
 227 */
 228QList *qdict_get_qlist(const QDict *qdict, const char *key)
 229{
 230    return qobject_to(QList, qdict_get(qdict, key));
 231}
 232
 233/**
 234 * qdict_get_qdict(): If @qdict maps @key to a QDict, return it, else NULL.
 235 */
 236QDict *qdict_get_qdict(const QDict *qdict, const char *key)
 237{
 238    return qobject_to(QDict, qdict_get(qdict, key));
 239}
 240
 241/**
 242 * qdict_get_str(): Get a pointer to the stored string mapped
 243 * by 'key'
 244 *
 245 * This function assumes that 'key' exists and it stores a
 246 * QString object.
 247 *
 248 * Return pointer to the string mapped by 'key'.
 249 */
 250const char *qdict_get_str(const QDict *qdict, const char *key)
 251{
 252    return qstring_get_str(qobject_to(QString, qdict_get(qdict, key)));
 253}
 254
 255/**
 256 * qdict_get_try_int(): Try to get integer mapped by 'key'
 257 *
 258 * Return integer mapped by 'key', if it is not present in the
 259 * dictionary or if the stored object is not a QNum representing an
 260 * integer, 'def_value' will be returned.
 261 */
 262int64_t qdict_get_try_int(const QDict *qdict, const char *key,
 263                          int64_t def_value)
 264{
 265    QNum *qnum = qobject_to(QNum, qdict_get(qdict, key));
 266    int64_t val;
 267
 268    if (!qnum || !qnum_get_try_int(qnum, &val)) {
 269        return def_value;
 270    }
 271
 272    return val;
 273}
 274
 275/**
 276 * qdict_get_try_bool(): Try to get a bool mapped by 'key'
 277 *
 278 * Return bool mapped by 'key', if it is not present in the
 279 * dictionary or if the stored object is not of QBool type
 280 * 'def_value' will be returned.
 281 */
 282bool qdict_get_try_bool(const QDict *qdict, const char *key, bool def_value)
 283{
 284    QBool *qbool = qobject_to(QBool, qdict_get(qdict, key));
 285
 286    return qbool ? qbool_get_bool(qbool) : def_value;
 287}
 288
 289/**
 290 * qdict_get_try_str(): Try to get a pointer to the stored string
 291 * mapped by 'key'
 292 *
 293 * Return a pointer to the string mapped by 'key', if it is not present
 294 * in the dictionary or if the stored object is not of QString type
 295 * NULL will be returned.
 296 */
 297const char *qdict_get_try_str(const QDict *qdict, const char *key)
 298{
 299    QString *qstr = qobject_to(QString, qdict_get(qdict, key));
 300
 301    return qstr ? qstring_get_str(qstr) : NULL;
 302}
 303
 304static QDictEntry *qdict_next_entry(const QDict *qdict, int first_bucket)
 305{
 306    int i;
 307
 308    for (i = first_bucket; i < QDICT_BUCKET_MAX; i++) {
 309        if (!QLIST_EMPTY(&qdict->table[i])) {
 310            return QLIST_FIRST(&qdict->table[i]);
 311        }
 312    }
 313
 314    return NULL;
 315}
 316
 317/**
 318 * qdict_first(): Return first qdict entry for iteration.
 319 */
 320const QDictEntry *qdict_first(const QDict *qdict)
 321{
 322    return qdict_next_entry(qdict, 0);
 323}
 324
 325/**
 326 * qdict_next(): Return next qdict entry in an iteration.
 327 */
 328const QDictEntry *qdict_next(const QDict *qdict, const QDictEntry *entry)
 329{
 330    QDictEntry *ret;
 331
 332    ret = QLIST_NEXT(entry, next);
 333    if (!ret) {
 334        unsigned int bucket = tdb_hash(entry->key) % QDICT_BUCKET_MAX;
 335        ret = qdict_next_entry(qdict, bucket + 1);
 336    }
 337
 338    return ret;
 339}
 340
 341/**
 342 * qdict_clone_shallow(): Clones a given QDict. Its entries are not copied, but
 343 * another reference is added.
 344 */
 345QDict *qdict_clone_shallow(const QDict *src)
 346{
 347    QDict *dest;
 348    QDictEntry *entry;
 349    int i;
 350
 351    dest = qdict_new();
 352
 353    for (i = 0; i < QDICT_BUCKET_MAX; i++) {
 354        QLIST_FOREACH(entry, &src->table[i], next) {
 355            qdict_put_obj(dest, entry->key, qobject_ref(entry->value));
 356        }
 357    }
 358
 359    return dest;
 360}
 361
 362/**
 363 * qentry_destroy(): Free all the memory allocated by a QDictEntry
 364 */
 365static void qentry_destroy(QDictEntry *e)
 366{
 367    assert(e != NULL);
 368    assert(e->key != NULL);
 369    assert(e->value != NULL);
 370
 371    qobject_unref(e->value);
 372    g_free(e->key);
 373    g_free(e);
 374}
 375
 376/**
 377 * qdict_del(): Delete a 'key:value' pair from the dictionary
 378 *
 379 * This will destroy all data allocated by this entry.
 380 */
 381void qdict_del(QDict *qdict, const char *key)
 382{
 383    QDictEntry *entry;
 384
 385    entry = qdict_find(qdict, key, tdb_hash(key) % QDICT_BUCKET_MAX);
 386    if (entry) {
 387        QLIST_REMOVE(entry, next);
 388        qentry_destroy(entry);
 389        qdict->size--;
 390    }
 391}
 392
 393/**
 394 * qdict_is_equal(): Test whether the two QDicts are equal
 395 *
 396 * Here, equality means whether they contain the same keys and whether
 397 * the respective values are in turn equal (i.e. invoking
 398 * qobject_is_equal() on them yields true).
 399 */
 400bool qdict_is_equal(const QObject *x, const QObject *y)
 401{
 402    const QDict *dict_x = qobject_to(QDict, x);
 403    const QDict *dict_y = qobject_to(QDict, y);
 404    const QDictEntry *e;
 405
 406    if (qdict_size(dict_x) != qdict_size(dict_y)) {
 407        return false;
 408    }
 409
 410    for (e = qdict_first(dict_x); e; e = qdict_next(dict_x, e)) {
 411        const QObject *obj_x = qdict_entry_value(e);
 412        const QObject *obj_y = qdict_get(dict_y, qdict_entry_key(e));
 413
 414        if (!qobject_is_equal(obj_x, obj_y)) {
 415            return false;
 416        }
 417    }
 418
 419    return true;
 420}
 421
 422/**
 423 * qdict_destroy_obj(): Free all the memory allocated by a QDict
 424 */
 425void qdict_destroy_obj(QObject *obj)
 426{
 427    int i;
 428    QDict *qdict;
 429
 430    assert(obj != NULL);
 431    qdict = qobject_to(QDict, obj);
 432
 433    for (i = 0; i < QDICT_BUCKET_MAX; i++) {
 434        QDictEntry *entry = QLIST_FIRST(&qdict->table[i]);
 435        while (entry) {
 436            QDictEntry *tmp = QLIST_NEXT(entry, next);
 437            QLIST_REMOVE(entry, next);
 438            qentry_destroy(entry);
 439            entry = tmp;
 440        }
 441    }
 442
 443    g_free(qdict);
 444}
 445