qdict.c

   1 /*
   2  * QDict data type.
   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 GPL, version 2.  See
  10  * the COPYING file in the top-level directory.
  11  */
  12
  13 #include "qint.h"
  14 #include "qdict.h"
  15 #include "qbool.h"
  16 #include "qstring.h"
  17 #include "qobject.h"
  18 #include "qemu-queue.h"
  19 #include "qemu-common.h"
  20
  21 static void qdict_destroy_obj(QObject *obj);
  22
  23 static const QType qdict_type = {
  24     .code = QTYPE_QDICT,
  25     .destroy = qdict_destroy_obj,
  26 };
  27
  28 /**
  29  * qdict_new(): Create a new QDict
  30  *
  31  * Return strong reference.
  32  */
  33 QDict *qdict_new(void)
  34 {
  35     QDict *qdict;
  36
  37     qdict = qemu_mallocz(sizeof(*qdict));
  38     QOBJECT_INIT(qdict, &qdict_type);
  39
  40     return qdict;
  41 }
  42
  43 /**
  44  * qobject_to_qdict(): Convert a QObject into a QDict
  45  */
  46 QDict *qobject_to_qdict(const QObject *obj)
  47 {
  48     if (qobject_type(obj) != QTYPE_QDICT)
  49         return NULL;
  50
  51     return container_of(obj, QDict, base);
  52 }
  53
  54 /**
  55  * tdb_hash(): based on the hash agorithm from gdbm, via tdb
  56  * (from module-init-tools)
  57  */
  58 static unsigned int tdb_hash(const char *name)
  59 {
  60     unsigned value;     /* Used to compute the hash value.  */
  61     unsigned   i;       /* Used to cycle through random values. */
  62
  63     /* Set the initial value from the key size. */
  64     for (value = 0x238F13AF * strlen(name), i=0; name[i]; i++)
  65         value = (value + (((const unsigned char *)name)[i] << (i*5 % 24)));
  66
  67     return (1103515243 * value + 12345);
  68 }
  69
  70 /**
  71  * alloc_entry(): allocate a new QDictEntry
  72  */
  73 static QDictEntry *alloc_entry(const char *key, QObject *value)
  74 {
  75     QDictEntry *entry;
  76
  77     entry = qemu_mallocz(sizeof(*entry));
  78     entry->key = qemu_strdup(key);
  79     entry->value = value;
  80
  81     return entry;
  82 }
  83
  84 /**
  85  * qdict_find(): List lookup function
  86  */
  87 static QDictEntry *qdict_find(const QDict *qdict,
  88                               const char *key, unsigned int hash)
  89 {
  90     QDictEntry *entry;
  91
  92     QLIST_FOREACH(entry, &qdict->table[hash], next)
  93         if (!strcmp(entry->key, key))
  94             return entry;
  95
  96     return NULL;
  97 }
  98
  99 /**
 100  * qdict_put_obj(): Put a new QObject into the dictionary
 101  *
 102  * Insert the pair 'key:value' into 'qdict', if 'key' already exists
 103  * its 'value' will be replaced.
 104  *
 105  * This is done by freeing the reference to the stored QObject and
 106  * storing the new one in the same entry.
 107  *
 108  * NOTE: ownership of 'value' is transferred to the QDict
 109  */
 110 void qdict_put_obj(QDict *qdict, const char *key, QObject *value)
 111 {
 112     unsigned int hash;
 113     QDictEntry *entry;
 114
 115     hash = tdb_hash(key) % QDICT_HASH_SIZE;
 116     entry = qdict_find(qdict, key, hash);
 117     if (entry) {
 118         /* replace key's value */
 119         qobject_decref(entry->value);
 120         entry->value = value;
 121     } else {
 122         /* allocate a new entry */
 123         entry = alloc_entry(key, value);
 124         QLIST_INSERT_HEAD(&qdict->table[hash], entry, next);
 125         qdict->size++;
 126     }
 127 }
 128
 129 /**
 130  * qdict_get(): Lookup for a given 'key'
 131  *
 132  * Return a weak reference to the QObject associated with 'key' if
 133  * 'key' is present in the dictionary, NULL otherwise.
 134  */
 135 QObject *qdict_get(const QDict *qdict, const char *key)
 136 {
 137     QDictEntry *entry;
 138
 139     entry = qdict_find(qdict, key, tdb_hash(key) % QDICT_HASH_SIZE);
 140     return (entry == NULL ? NULL : entry->value);
 141 }
 142
 143 /**
 144  * qdict_haskey(): Check if 'key' exists
 145  *
 146  * Return 1 if 'key' exists in the dict, 0 otherwise
 147  */
 148 int qdict_haskey(const QDict *qdict, const char *key)
 149 {
 150     unsigned int hash = tdb_hash(key) % QDICT_HASH_SIZE;
 151     return (qdict_find(qdict, key, hash) == NULL ? 0 : 1);
 152 }
 153
 154 /**
 155  * qdict_size(): Return the size of the dictionary
 156  */
 157 size_t qdict_size(const QDict *qdict)
 158 {
 159     return qdict->size;
 160 }
 161
 162 /**
 163  * qdict_get_obj(): Get a QObject of a specific type
 164  */
 165 static QObject *qdict_get_obj(const QDict *qdict, const char *key,
 166                               qtype_code type)
 167 {
 168     QObject *obj;
 169
 170     obj = qdict_get(qdict, key);
 171     assert(obj != NULL);
 172     assert(qobject_type(obj) == type);
 173
 174     return obj;
 175 }
 176
 177 /**
 178  * qdict_get_int(): Get an integer mapped by 'key'
 179  *
 180  * This function assumes that 'key' exists and it stores a
 181  * QInt object.
 182  *
 183  * Return integer mapped by 'key'.
 184  */
 185 int64_t qdict_get_int(const QDict *qdict, const char *key)
 186 {
 187     QObject *obj = qdict_get_obj(qdict, key, QTYPE_QINT);
 188     return qint_get_int(qobject_to_qint(obj));
 189 }
 190
 191 /**
 192  * qdict_get_bool(): Get a bool mapped by 'key'
 193  *
 194  * This function assumes that 'key' exists and it stores a
 195  * QBool object.
 196  *
 197  * Return bool mapped by 'key'.
 198  */
 199 int qdict_get_bool(const QDict *qdict, const char *key)
 200 {
 201     QObject *obj = qdict_get_obj(qdict, key, QTYPE_QBOOL);
 202     return qbool_get_int(qobject_to_qbool(obj));
 203 }
 204
 205 /**
 206  * qdict_get_qlist(): Get the QList mapped by 'key'
 207  *
 208  * This function assumes that 'key' exists and it stores a
 209  * QList object.
 210  *
 211  * Return QList mapped by 'key'.
 212  */
 213 QList *qdict_get_qlist(const QDict *qdict, const char *key)
 214 {
 215     return qobject_to_qlist(qdict_get_obj(qdict, key, QTYPE_QLIST));
 216 }
 217
 218 /**
 219  * qdict_get_str(): Get a pointer to the stored string mapped
 220  * by 'key'
 221  *
 222  * This function assumes that 'key' exists and it stores a
 223  * QString object.
 224  *
 225  * Return pointer to the string mapped by 'key'.
 226  */
 227 const char *qdict_get_str(const QDict *qdict, const char *key)
 228 {
 229     QObject *obj = qdict_get_obj(qdict, key, QTYPE_QSTRING);
 230     return qstring_get_str(qobject_to_qstring(obj));
 231 }
 232
 233 /**
 234  * qdict_get_try_int(): Try to get integer mapped by 'key'
 235  *
 236  * Return integer mapped by 'key', if it is not present in
 237  * the dictionary or if the stored object is not of QInt type
 238  * 'err_value' will be returned.
 239  */
 240 int64_t qdict_get_try_int(const QDict *qdict, const char *key,
 241                           int64_t err_value)
 242 {
 243     QObject *obj;
 244
 245     obj = qdict_get(qdict, key);
 246     if (!obj || qobject_type(obj) != QTYPE_QINT)
 247         return err_value;
 248
 249     return qint_get_int(qobject_to_qint(obj));
 250 }
 251
 252 /**
 253  * qdict_get_try_str(): Try to get a pointer to the stored string
 254  * mapped by 'key'
 255  *
 256  * Return a pointer to the string mapped by 'key', if it is not present
 257  * in the dictionary or if the stored object is not of QString type
 258  * NULL will be returned.
 259  */
 260 const char *qdict_get_try_str(const QDict *qdict, const char *key)
 261 {
 262     QObject *obj;
 263
 264     obj = qdict_get(qdict, key);
 265     if (!obj || qobject_type(obj) != QTYPE_QSTRING)
 266         return NULL;
 267
 268     return qstring_get_str(qobject_to_qstring(obj));
 269 }
 270
 271 /**
 272  * qdict_iter(): Iterate over all the dictionary's stored values.
 273  *
 274  * This function allows the user to provide an iterator, which will be
 275  * called for each stored value in the dictionary.
 276  */
 277 void qdict_iter(const QDict *qdict,
 278                 void (*iter)(const char *key, QObject *obj, void *opaque),
 279                 void *opaque)
 280 {
 281     int i;
 282     QDictEntry *entry;
 283
 284     for (i = 0; i < QDICT_HASH_SIZE; i++) {
 285         QLIST_FOREACH(entry, &qdict->table[i], next)
 286             iter(entry->key, entry->value, opaque);
 287     }
 288 }
 289
 290 /**
 291  * qentry_destroy(): Free all the memory allocated by a QDictEntry
 292  */
 293 static void qentry_destroy(QDictEntry *e)
 294 {
 295     assert(e != NULL);
 296     assert(e->key != NULL);
 297     assert(e->value != NULL);
 298
 299     qobject_decref(e->value);
 300     qemu_free(e->key);
 301     qemu_free(e);
 302 }
 303
 304 /**
 305  * qdict_del(): Delete a 'key:value' pair from the dictionary
 306  *
 307  * This will destroy all data allocated by this entry.
 308  */
 309 void qdict_del(QDict *qdict, const char *key)
 310 {
 311     QDictEntry *entry;
 312
 313     entry = qdict_find(qdict, key, tdb_hash(key) % QDICT_HASH_SIZE);
 314     if (entry) {
 315         QLIST_REMOVE(entry, next);
 316         qentry_destroy(entry);
 317         qdict->size--;
 318     }
 319 }
 320
 321 /**
 322  * qdict_destroy_obj(): Free all the memory allocated by a QDict
 323  */
 324 static void qdict_destroy_obj(QObject *obj)
 325 {
 326     int i;
 327     QDict *qdict;
 328
 329     assert(obj != NULL);
 330     qdict = qobject_to_qdict(obj);
 331
 332     for (i = 0; i < QDICT_HASH_SIZE; i++) {
 333         QDictEntry *entry = QLIST_FIRST(&qdict->table[i]);
 334         while (entry) {
 335             QDictEntry *tmp = QLIST_NEXT(entry, next);
 336             QLIST_REMOVE(entry, next);
 337             qentry_destroy(entry);
 338             entry = tmp;
 339         }
 340     }
 341
 342     qemu_free(qdict);
 343 }