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/qint.h"
  15 #include "qapi/qmp/qfloat.h"
  16 #include "qapi/qmp/qdict.h"
  17 #include "qapi/qmp/qbool.h"
  18 #include "qapi/qmp/qstring.h"
  19 #include "qapi/qmp/qobject.h"
  20 #include "qemu/queue.h"
  21 #include "qemu-common.h"
  22
  23 /**
  24  * qdict_new(): Create a new QDict
  25  *
  26  * Return strong reference.
  27  */
  28 QDict *qdict_new(void)
  29 {
  30     QDict *qdict;
  31
  32     qdict = g_malloc0(sizeof(*qdict));
  33     qobject_init(QOBJECT(qdict), QTYPE_QDICT);
  34
  35     return qdict;
  36 }
  37
  38 /**
  39  * qobject_to_qdict(): Convert a QObject into a QDict
  40  */
  41 QDict *qobject_to_qdict(const QObject *obj)
  42 {
  43     if (!obj || qobject_type(obj) != QTYPE_QDICT) {
  44         return NULL;
  45     }
  46     return container_of(obj, QDict, base);
  47 }
  48
  49 /**
  50  * tdb_hash(): based on the hash agorithm from gdbm, via tdb
  51  * (from module-init-tools)
  52  */
  53 static unsigned int tdb_hash(const char *name)
  54 {
  55     unsigned value;     /* Used to compute the hash value.  */
  56     unsigned   i;       /* Used to cycle through random values. */
  57
  58     /* Set the initial value from the key size. */
  59     for (value = 0x238F13AF * strlen(name), i=0; name[i]; i++)
  60         value = (value + (((const unsigned char *)name)[i] << (i*5 % 24)));
  61
  62     return (1103515243 * value + 12345);
  63 }
  64
  65 /**
  66  * alloc_entry(): allocate a new QDictEntry
  67  */
  68 static QDictEntry *alloc_entry(const char *key, QObject *value)
  69 {
  70     QDictEntry *entry;
  71
  72     entry = g_malloc0(sizeof(*entry));
  73     entry->key = g_strdup(key);
  74     entry->value = value;
  75
  76     return entry;
  77 }
  78
  79 /**
  80  * qdict_entry_value(): Return qdict entry value
  81  *
  82  * Return weak reference.
  83  */
  84 QObject *qdict_entry_value(const QDictEntry *entry)
  85 {
  86     return entry->value;
  87 }
  88
  89 /**
  90  * qdict_entry_key(): Return qdict entry key
  91  *
  92  * Return a *pointer* to the string, it has to be duplicated before being
  93  * stored.
  94  */
  95 const char *qdict_entry_key(const QDictEntry *entry)
  96 {
  97     return entry->key;
  98 }
  99
 100 /**
 101  * qdict_find(): List lookup function
 102  */
 103 static QDictEntry *qdict_find(const QDict *qdict,
 104                               const char *key, unsigned int bucket)
 105 {
 106     QDictEntry *entry;
 107
 108     QLIST_FOREACH(entry, &qdict->table[bucket], next)
 109         if (!strcmp(entry->key, key))
 110             return entry;
 111
 112     return NULL;
 113 }
 114
 115 /**
 116  * qdict_put_obj(): Put a new QObject into the dictionary
 117  *
 118  * Insert the pair 'key:value' into 'qdict', if 'key' already exists
 119  * its 'value' will be replaced.
 120  *
 121  * This is done by freeing the reference to the stored QObject and
 122  * storing the new one in the same entry.
 123  *
 124  * NOTE: ownership of 'value' is transferred to the QDict
 125  */
 126 void qdict_put_obj(QDict *qdict, const char *key, QObject *value)
 127 {
 128     unsigned int bucket;
 129     QDictEntry *entry;
 130
 131     bucket = tdb_hash(key) % QDICT_BUCKET_MAX;
 132     entry = qdict_find(qdict, key, bucket);
 133     if (entry) {
 134         /* replace key's value */
 135         qobject_decref(entry->value);
 136         entry->value = value;
 137     } else {
 138         /* allocate a new entry */
 139         entry = alloc_entry(key, value);
 140         QLIST_INSERT_HEAD(&qdict->table[bucket], entry, next);
 141         qdict->size++;
 142     }
 143 }
 144
 145 /**
 146  * qdict_get(): Lookup for a given 'key'
 147  *
 148  * Return a weak reference to the QObject associated with 'key' if
 149  * 'key' is present in the dictionary, NULL otherwise.
 150  */
 151 QObject *qdict_get(const QDict *qdict, const char *key)
 152 {
 153     QDictEntry *entry;
 154
 155     entry = qdict_find(qdict, key, tdb_hash(key) % QDICT_BUCKET_MAX);
 156     return (entry == NULL ? NULL : entry->value);
 157 }
 158
 159 /**
 160  * qdict_haskey(): Check if 'key' exists
 161  *
 162  * Return 1 if 'key' exists in the dict, 0 otherwise
 163  */
 164 int qdict_haskey(const QDict *qdict, const char *key)
 165 {
 166     unsigned int bucket = tdb_hash(key) % QDICT_BUCKET_MAX;
 167     return (qdict_find(qdict, key, bucket) == NULL ? 0 : 1);
 168 }
 169
 170 /**
 171  * qdict_size(): Return the size of the dictionary
 172  */
 173 size_t qdict_size(const QDict *qdict)
 174 {
 175     return qdict->size;
 176 }
 177
 178 /**
 179  * qdict_get_obj(): Get a QObject of a specific type
 180  */
 181 static QObject *qdict_get_obj(const QDict *qdict, const char *key, QType type)
 182 {
 183     QObject *obj;
 184
 185     obj = qdict_get(qdict, key);
 186     assert(obj != NULL);
 187     assert(qobject_type(obj) == type);
 188
 189     return obj;
 190 }
 191
 192 /**
 193  * qdict_get_double(): Get an number mapped by 'key'
 194  *
 195  * This function assumes that 'key' exists and it stores a
 196  * QFloat or QInt object.
 197  *
 198  * Return number mapped by 'key'.
 199  */
 200 double qdict_get_double(const QDict *qdict, const char *key)
 201 {
 202     QObject *obj = qdict_get(qdict, key);
 203
 204     assert(obj);
 205     switch (qobject_type(obj)) {
 206     case QTYPE_QFLOAT:
 207         return qfloat_get_double(qobject_to_qfloat(obj));
 208     case QTYPE_QINT:
 209         return qint_get_int(qobject_to_qint(obj));
 210     default:
 211         abort();
 212     }
 213 }
 214
 215 /**
 216  * qdict_get_int(): Get an integer mapped by 'key'
 217  *
 218  * This function assumes that 'key' exists and it stores a
 219  * QInt object.
 220  *
 221  * Return integer mapped by 'key'.
 222  */
 223 int64_t qdict_get_int(const QDict *qdict, const char *key)
 224 {
 225     return qint_get_int(qobject_to_qint(qdict_get(qdict, key)));
 226 }
 227
 228 /**
 229  * qdict_get_bool(): Get a bool mapped by 'key'
 230  *
 231  * This function assumes that 'key' exists and it stores a
 232  * QBool object.
 233  *
 234  * Return bool mapped by 'key'.
 235  */
 236 bool qdict_get_bool(const QDict *qdict, const char *key)
 237 {
 238     return qbool_get_bool(qobject_to_qbool(qdict_get(qdict, key)));
 239 }
 240
 241 /**
 242  * qdict_get_qlist(): Get the QList mapped by 'key'
 243  *
 244  * This function assumes that 'key' exists and it stores a
 245  * QList object.
 246  *
 247  * Return QList mapped by 'key'.
 248  */
 249 QList *qdict_get_qlist(const QDict *qdict, const char *key)
 250 {
 251     return qobject_to_qlist(qdict_get_obj(qdict, key, QTYPE_QLIST));
 252 }
 253
 254 /**
 255  * qdict_get_qdict(): Get the QDict mapped by 'key'
 256  *
 257  * This function assumes that 'key' exists and it stores a
 258  * QDict object.
 259  *
 260  * Return QDict mapped by 'key'.
 261  */
 262 QDict *qdict_get_qdict(const QDict *qdict, const char *key)
 263 {
 264     return qobject_to_qdict(qdict_get(qdict, key));
 265 }
 266
 267 /**
 268  * qdict_get_str(): Get a pointer to the stored string mapped
 269  * by 'key'
 270  *
 271  * This function assumes that 'key' exists and it stores a
 272  * QString object.
 273  *
 274  * Return pointer to the string mapped by 'key'.
 275  */
 276 const char *qdict_get_str(const QDict *qdict, const char *key)
 277 {
 278     return qstring_get_str(qobject_to_qstring(qdict_get(qdict, key)));
 279 }
 280
 281 /**
 282  * qdict_get_try_int(): Try to get integer mapped by 'key'
 283  *
 284  * Return integer mapped by 'key', if it is not present in
 285  * the dictionary or if the stored object is not of QInt type
 286  * 'def_value' will be returned.
 287  */
 288 int64_t qdict_get_try_int(const QDict *qdict, const char *key,
 289                           int64_t def_value)
 290 {
 291     QInt *qint = qobject_to_qint(qdict_get(qdict, key));
 292
 293     return qint ? qint_get_int(qint) : def_value;
 294 }
 295
 296 /**
 297  * qdict_get_try_bool(): Try to get a bool mapped by 'key'
 298  *
 299  * Return bool mapped by 'key', if it is not present in the
 300  * dictionary or if the stored object is not of QBool type
 301  * 'def_value' will be returned.
 302  */
 303 bool qdict_get_try_bool(const QDict *qdict, const char *key, bool def_value)
 304 {
 305     QBool *qbool = qobject_to_qbool(qdict_get(qdict, key));
 306
 307     return qbool ? qbool_get_bool(qbool) : def_value;
 308 }
 309
 310 /**
 311  * qdict_get_try_str(): Try to get a pointer to the stored string
 312  * mapped by 'key'
 313  *
 314  * Return a pointer to the string mapped by 'key', if it is not present
 315  * in the dictionary or if the stored object is not of QString type
 316  * NULL will be returned.
 317  */
 318 const char *qdict_get_try_str(const QDict *qdict, const char *key)
 319 {
 320     QString *qstr = qobject_to_qstring(qdict_get(qdict, key));
 321
 322     return qstr ? qstring_get_str(qstr) : NULL;
 323 }
 324
 325 /**
 326  * qdict_iter(): Iterate over all the dictionary's stored values.
 327  *
 328  * This function allows the user to provide an iterator, which will be
 329  * called for each stored value in the dictionary.
 330  */
 331 void qdict_iter(const QDict *qdict,
 332                 void (*iter)(const char *key, QObject *obj, void *opaque),
 333                 void *opaque)
 334 {
 335     int i;
 336     QDictEntry *entry;
 337
 338     for (i = 0; i < QDICT_BUCKET_MAX; i++) {
 339         QLIST_FOREACH(entry, &qdict->table[i], next)
 340             iter(entry->key, entry->value, opaque);
 341     }
 342 }
 343
 344 static QDictEntry *qdict_next_entry(const QDict *qdict, int first_bucket)
 345 {
 346     int i;
 347
 348     for (i = first_bucket; i < QDICT_BUCKET_MAX; i++) {
 349         if (!QLIST_EMPTY(&qdict->table[i])) {
 350             return QLIST_FIRST(&qdict->table[i]);
 351         }
 352     }
 353
 354     return NULL;
 355 }
 356
 357 /**
 358  * qdict_first(): Return first qdict entry for iteration.
 359  */
 360 const QDictEntry *qdict_first(const QDict *qdict)
 361 {
 362     return qdict_next_entry(qdict, 0);
 363 }
 364
 365 /**
 366  * qdict_next(): Return next qdict entry in an iteration.
 367  */
 368 const QDictEntry *qdict_next(const QDict *qdict, const QDictEntry *entry)
 369 {
 370     QDictEntry *ret;
 371
 372     ret = QLIST_NEXT(entry, next);
 373     if (!ret) {
 374         unsigned int bucket = tdb_hash(entry->key) % QDICT_BUCKET_MAX;
 375         ret = qdict_next_entry(qdict, bucket + 1);
 376     }
 377
 378     return ret;
 379 }
 380
 381 /**
 382  * qdict_clone_shallow(): Clones a given QDict. Its entries are not copied, but
 383  * another reference is added.
 384  */
 385 QDict *qdict_clone_shallow(const QDict *src)
 386 {
 387     QDict *dest;
 388     QDictEntry *entry;
 389     int i;
 390
 391     dest = qdict_new();
 392
 393     for (i = 0; i < QDICT_BUCKET_MAX; i++) {
 394         QLIST_FOREACH(entry, &src->table[i], next) {
 395             qobject_incref(entry->value);
 396             qdict_put_obj(dest, entry->key, entry->value);
 397         }
 398     }
 399
 400     return dest;
 401 }
 402
 403 /**
 404  * qentry_destroy(): Free all the memory allocated by a QDictEntry
 405  */
 406 static 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     g_free(e->key);
 414     g_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  */
 422 void 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  */
 437 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     g_free(qdict);
 456 }
 457
 458 /**
 459  * qdict_copy_default(): If no entry mapped by 'key' exists in 'dst' yet, the
 460  * value of 'key' in 'src' is copied there (and the refcount increased
 461  * accordingly).
 462  */
 463 void qdict_copy_default(QDict *dst, QDict *src, const char *key)
 464 {
 465     QObject *val;
 466
 467     if (qdict_haskey(dst, key)) {
 468         return;
 469     }
 470
 471     val = qdict_get(src, key);
 472     if (val) {
 473         qobject_incref(val);
 474         qdict_put_obj(dst, key, val);
 475     }
 476 }
 477
 478 /**
 479  * qdict_set_default_str(): If no entry mapped by 'key' exists in 'dst' yet, a
 480  * new QString initialised by 'val' is put there.
 481  */
 482 void qdict_set_default_str(QDict *dst, const char *key, const char *val)
 483 {
 484     if (qdict_haskey(dst, key)) {
 485         return;
 486     }
 487
 488     qdict_put(dst, key, qstring_from_str(val));
 489 }
 490
 491 static void qdict_flatten_qdict(QDict *qdict, QDict *target,
 492                                 const char *prefix);
 493
 494 static void qdict_flatten_qlist(QList *qlist, QDict *target, const char *prefix)
 495 {
 496     QObject *value;
 497     const QListEntry *entry;
 498     char *new_key;
 499     int i;
 500
 501     /* This function is never called with prefix == NULL, i.e., it is always
 502      * called from within qdict_flatten_q(list|dict)(). Therefore, it does not
 503      * need to remove list entries during the iteration (the whole list will be
 504      * deleted eventually anyway from qdict_flatten_qdict()). */
 505     assert(prefix);
 506
 507     entry = qlist_first(qlist);
 508
 509     for (i = 0; entry; entry = qlist_next(entry), i++) {
 510         value = qlist_entry_obj(entry);
 511         new_key = g_strdup_printf("%s.%i", prefix, i);
 512
 513         if (qobject_type(value) == QTYPE_QDICT) {
 514             qdict_flatten_qdict(qobject_to_qdict(value), target, new_key);
 515         } else if (qobject_type(value) == QTYPE_QLIST) {
 516             qdict_flatten_qlist(qobject_to_qlist(value), target, new_key);
 517         } else {
 518             /* All other types are moved to the target unchanged. */
 519             qobject_incref(value);
 520             qdict_put_obj(target, new_key, value);
 521         }
 522
 523         g_free(new_key);
 524     }
 525 }
 526
 527 static void qdict_flatten_qdict(QDict *qdict, QDict *target, const char *prefix)
 528 {
 529     QObject *value;
 530     const QDictEntry *entry, *next;
 531     char *new_key;
 532     bool delete;
 533
 534     entry = qdict_first(qdict);
 535
 536     while (entry != NULL) {
 537
 538         next = qdict_next(qdict, entry);
 539         value = qdict_entry_value(entry);
 540         new_key = NULL;
 541         delete = false;
 542
 543         if (prefix) {
 544             new_key = g_strdup_printf("%s.%s", prefix, entry->key);
 545         }
 546
 547         if (qobject_type(value) == QTYPE_QDICT) {
 548             /* Entries of QDicts are processed recursively, the QDict object
 549              * itself disappears. */
 550             qdict_flatten_qdict(qobject_to_qdict(value), target,
 551                                 new_key ? new_key : entry->key);
 552             delete = true;
 553         } else if (qobject_type(value) == QTYPE_QLIST) {
 554             qdict_flatten_qlist(qobject_to_qlist(value), target,
 555                                 new_key ? new_key : entry->key);
 556             delete = true;
 557         } else if (prefix) {
 558             /* All other objects are moved to the target unchanged. */
 559             qobject_incref(value);
 560             qdict_put_obj(target, new_key, value);
 561             delete = true;
 562         }
 563
 564         g_free(new_key);
 565
 566         if (delete) {
 567             qdict_del(qdict, entry->key);
 568
 569             /* Restart loop after modifying the iterated QDict */
 570             entry = qdict_first(qdict);
 571             continue;
 572         }
 573
 574         entry = next;
 575     }
 576 }
 577
 578 /**
 579  * qdict_flatten(): For each nested QDict with key x, all fields with key y
 580  * are moved to this QDict and their key is renamed to "x.y". For each nested
 581  * QList with key x, the field at index y is moved to this QDict with the key
 582  * "x.y" (i.e., the reverse of what qdict_array_split() does).
 583  * This operation is applied recursively for nested QDicts and QLists.
 584  */
 585 void qdict_flatten(QDict *qdict)
 586 {
 587     qdict_flatten_qdict(qdict, qdict, NULL);
 588 }
 589
 590 /* extract all the src QDict entries starting by start into dst */
 591 void qdict_extract_subqdict(QDict *src, QDict **dst, const char *start)
 592
 593 {
 594     const QDictEntry *entry, *next;
 595     const char *p;
 596
 597     *dst = qdict_new();
 598     entry = qdict_first(src);
 599
 600     while (entry != NULL) {
 601         next = qdict_next(src, entry);
 602         if (strstart(entry->key, start, &p)) {
 603             qobject_incref(entry->value);
 604             qdict_put_obj(*dst, p, entry->value);
 605             qdict_del(src, entry->key);
 606         }
 607         entry = next;
 608     }
 609 }
 610
 611 static int qdict_count_prefixed_entries(const QDict *src, const char *start)
 612 {
 613     const QDictEntry *entry;
 614     int count = 0;
 615
 616     for (entry = qdict_first(src); entry; entry = qdict_next(src, entry)) {
 617         if (strstart(entry->key, start, NULL)) {
 618             if (count == INT_MAX) {
 619                 return -ERANGE;
 620             }
 621             count++;
 622         }
 623     }
 624
 625     return count;
 626 }
 627
 628 /**
 629  * qdict_array_split(): This function moves array-like elements of a QDict into
 630  * a new QList. Every entry in the original QDict with a key "%u" or one
 631  * prefixed "%u.", where %u designates an unsigned integer starting at 0 and
 632  * incrementally counting up, will be moved to a new QDict at index %u in the
 633  * output QList with the key prefix removed, if that prefix is "%u.". If the
 634  * whole key is just "%u", the whole QObject will be moved unchanged without
 635  * creating a new QDict. The function terminates when there is no entry in the
 636  * QDict with a prefix directly (incrementally) following the last one; it also
 637  * returns if there are both entries with "%u" and "%u." for the same index %u.
 638  * Example: {"0.a": 42, "0.b": 23, "1.x": 0, "4.y": 1, "o.o": 7, "2": 66}
 639  *      (or {"1.x": 0, "4.y": 1, "0.a": 42, "o.o": 7, "0.b": 23, "2": 66})
 640  *       => [{"a": 42, "b": 23}, {"x": 0}, 66]
 641  *      and {"4.y": 1, "o.o": 7} (remainder of the old QDict)
 642  */
 643 void qdict_array_split(QDict *src, QList **dst)
 644 {
 645     unsigned i;
 646
 647     *dst = qlist_new();
 648
 649     for (i = 0; i < UINT_MAX; i++) {
 650         QObject *subqobj;
 651         bool is_subqdict;
 652         QDict *subqdict;
 653         char indexstr[32], prefix[32];
 654         size_t snprintf_ret;
 655
 656         snprintf_ret = snprintf(indexstr, 32, "%u", i);
 657         assert(snprintf_ret < 32);
 658
 659         subqobj = qdict_get(src, indexstr);
 660
 661         snprintf_ret = snprintf(prefix, 32, "%u.", i);
 662         assert(snprintf_ret < 32);
 663
 664         /* Overflow is the same as positive non-zero results */
 665         is_subqdict = qdict_count_prefixed_entries(src, prefix);
 666
 667         // There may be either a single subordinate object (named "%u") or
 668         // multiple objects (each with a key prefixed "%u."), but not both.
 669         if (!subqobj == !is_subqdict) {
 670             break;
 671         }
 672
 673         if (is_subqdict) {
 674             qdict_extract_subqdict(src, &subqdict, prefix);
 675             assert(qdict_size(subqdict) > 0);
 676         } else {
 677             qobject_incref(subqobj);
 678             qdict_del(src, indexstr);
 679         }
 680
 681         qlist_append_obj(*dst, subqobj ?: QOBJECT(subqdict));
 682     }
 683 }
 684
 685 /**
 686  * qdict_array_entries(): Returns the number of direct array entries if the
 687  * sub-QDict of src specified by the prefix in subqdict (or src itself for
 688  * prefix == "") is valid as an array, i.e. the length of the created list if
 689  * the sub-QDict would become empty after calling qdict_array_split() on it. If
 690  * the array is not valid, -EINVAL is returned.
 691  */
 692 int qdict_array_entries(QDict *src, const char *subqdict)
 693 {
 694     const QDictEntry *entry;
 695     unsigned i;
 696     unsigned entries = 0;
 697     size_t subqdict_len = strlen(subqdict);
 698
 699     assert(!subqdict_len || subqdict[subqdict_len - 1] == '.');
 700
 701     /* qdict_array_split() loops until UINT_MAX, but as we want to return
 702      * negative errors, we only have a signed return value here. Any additional
 703      * entries will lead to -EINVAL. */
 704     for (i = 0; i < INT_MAX; i++) {
 705         QObject *subqobj;
 706         int subqdict_entries;
 707         size_t slen = 32 + subqdict_len;
 708         char indexstr[slen], prefix[slen];
 709         size_t snprintf_ret;
 710
 711         snprintf_ret = snprintf(indexstr, slen, "%s%u", subqdict, i);
 712         assert(snprintf_ret < slen);
 713
 714         subqobj = qdict_get(src, indexstr);
 715
 716         snprintf_ret = snprintf(prefix, slen, "%s%u.", subqdict, i);
 717         assert(snprintf_ret < slen);
 718
 719         subqdict_entries = qdict_count_prefixed_entries(src, prefix);
 720         if (subqdict_entries < 0) {
 721             return subqdict_entries;
 722         }
 723
 724         /* There may be either a single subordinate object (named "%u") or
 725          * multiple objects (each with a key prefixed "%u."), but not both. */
 726         if (subqobj && subqdict_entries) {
 727             return -EINVAL;
 728         } else if (!subqobj && !subqdict_entries) {
 729             break;
 730         }
 731
 732         entries += subqdict_entries ? subqdict_entries : 1;
 733     }
 734
 735     /* Consider everything handled that isn't part of the given sub-QDict */
 736     for (entry = qdict_first(src); entry; entry = qdict_next(src, entry)) {
 737         if (!strstart(qdict_entry_key(entry), subqdict, NULL)) {
 738             entries++;
 739         }
 740     }
 741
 742     /* Anything left in the sub-QDict that wasn't handled? */
 743     if (qdict_size(src) != entries) {
 744         return -EINVAL;
 745     }
 746
 747     return i;
 748 }
 749
 750 /**
 751  * qdict_join(): Absorb the src QDict into the dest QDict, that is, move all
 752  * elements from src to dest.
 753  *
 754  * If an element from src has a key already present in dest, it will not be
 755  * moved unless overwrite is true.
 756  *
 757  * If overwrite is true, the conflicting values in dest will be discarded and
 758  * replaced by the corresponding values from src.
 759  *
 760  * Therefore, with overwrite being true, the src QDict will always be empty when
 761  * this function returns. If overwrite is false, the src QDict will be empty
 762  * iff there were no conflicts.
 763  */
 764 void qdict_join(QDict *dest, QDict *src, bool overwrite)
 765 {
 766     const QDictEntry *entry, *next;
 767
 768     entry = qdict_first(src);
 769     while (entry) {
 770         next = qdict_next(src, entry);
 771
 772         if (overwrite || !qdict_haskey(dest, entry->key)) {
 773             qobject_incref(entry->value);
 774             qdict_put_obj(dest, entry->key, entry->value);
 775             qdict_del(src, entry->key);
 776         }
 777
 778         entry = next;
 779     }
 780 }