qom/object.c

   1 /*
   2  * QEMU Object Model
   3  *
   4  * Copyright IBM, Corp. 2011
   5  *
   6  * Authors:
   7  *  Anthony Liguori   <aliguori@us.ibm.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  10  * See the COPYING file in the top-level directory.
  11  */
  12
  13 #include "qemu/object.h"
  14 #include "qemu-common.h"
  15 #include "qapi/qapi-visit-core.h"
  16 #include "qapi/string-input-visitor.h"
  17 #include "qapi/string-output-visitor.h"
  18
  19 /* TODO: replace QObject with a simpler visitor to avoid a dependency
  20  * of the QOM core on QObject?  */
  21 #include "qemu/qom-qobject.h"
  22 #include "qobject.h"
  23 #include "qbool.h"
  24 #include "qint.h"
  25 #include "qstring.h"
  26
  27 #define MAX_INTERFACES 32
  28
  29 typedef struct InterfaceImpl InterfaceImpl;
  30 typedef struct TypeImpl TypeImpl;
  31
  32 struct InterfaceImpl
  33 {
  34     const char *parent;
  35     void (*interface_initfn)(ObjectClass *class, void *data);
  36     TypeImpl *type;
  37 };
  38
  39 struct TypeImpl
  40 {
  41     const char *name;
  42
  43     size_t class_size;
  44
  45     size_t instance_size;
  46
  47     void (*class_init)(ObjectClass *klass, void *data);
  48     void (*class_base_init)(ObjectClass *klass, void *data);
  49     void (*class_finalize)(ObjectClass *klass, void *data);
  50
  51     void *class_data;
  52
  53     void (*instance_init)(Object *obj);
  54     void (*instance_finalize)(Object *obj);
  55
  56     bool abstract;
  57
  58     const char *parent;
  59     TypeImpl *parent_type;
  60
  61     ObjectClass *class;
  62
  63     int num_interfaces;
  64     InterfaceImpl interfaces[MAX_INTERFACES];
  65 };
  66
  67 typedef struct Interface
  68 {
  69     Object parent;
  70     Object *obj;
  71 } Interface;
  72
  73 #define INTERFACE(obj) OBJECT_CHECK(Interface, obj, TYPE_INTERFACE)
  74
  75 static Type type_interface;
  76
  77 static GHashTable *type_table_get(void)
  78 {
  79     static GHashTable *type_table;
  80
  81     if (type_table == NULL) {
  82         type_table = g_hash_table_new(g_str_hash, g_str_equal);
  83     }
  84
  85     return type_table;
  86 }
  87
  88 static void type_table_add(TypeImpl *ti)
  89 {
  90     g_hash_table_insert(type_table_get(), (void *)ti->name, ti);
  91 }
  92
  93 static TypeImpl *type_table_lookup(const char *name)
  94 {
  95     return g_hash_table_lookup(type_table_get(), name);
  96 }
  97
  98 static TypeImpl *type_register_internal(const TypeInfo *info)
  99 {
 100     TypeImpl *ti = g_malloc0(sizeof(*ti));
 101
 102     g_assert(info->name != NULL);
 103
 104     if (type_table_lookup(info->name) != NULL) {
 105         fprintf(stderr, "Registering `%s' which already exists\n", info->name);
 106         abort();
 107     }
 108
 109     ti->name = g_strdup(info->name);
 110     ti->parent = g_strdup(info->parent);
 111
 112     ti->class_size = info->class_size;
 113     ti->instance_size = info->instance_size;
 114
 115     ti->class_init = info->class_init;
 116     ti->class_base_init = info->class_base_init;
 117     ti->class_finalize = info->class_finalize;
 118     ti->class_data = info->class_data;
 119
 120     ti->instance_init = info->instance_init;
 121     ti->instance_finalize = info->instance_finalize;
 122
 123     ti->abstract = info->abstract;
 124
 125     if (info->interfaces) {
 126         int i;
 127
 128         for (i = 0; info->interfaces[i].type; i++) {
 129             ti->interfaces[i].parent = info->interfaces[i].type;
 130             ti->interfaces[i].interface_initfn = info->interfaces[i].interface_initfn;
 131             ti->num_interfaces++;
 132         }
 133     }
 134
 135     type_table_add(ti);
 136
 137     return ti;
 138 }
 139
 140 TypeImpl *type_register(const TypeInfo *info)
 141 {
 142     assert(info->parent);
 143     return type_register_internal(info);
 144 }
 145
 146 TypeImpl *type_register_static(const TypeInfo *info)
 147 {
 148     return type_register(info);
 149 }
 150
 151 static TypeImpl *type_get_by_name(const char *name)
 152 {
 153     if (name == NULL) {
 154         return NULL;
 155     }
 156
 157     return type_table_lookup(name);
 158 }
 159
 160 static TypeImpl *type_get_parent(TypeImpl *type)
 161 {
 162     if (!type->parent_type && type->parent) {
 163         type->parent_type = type_get_by_name(type->parent);
 164         g_assert(type->parent_type != NULL);
 165     }
 166
 167     return type->parent_type;
 168 }
 169
 170 static bool type_has_parent(TypeImpl *type)
 171 {
 172     return (type->parent != NULL);
 173 }
 174
 175 static size_t type_class_get_size(TypeImpl *ti)
 176 {
 177     if (ti->class_size) {
 178         return ti->class_size;
 179     }
 180
 181     if (type_has_parent(ti)) {
 182         return type_class_get_size(type_get_parent(ti));
 183     }
 184
 185     return sizeof(ObjectClass);
 186 }
 187
 188 static size_t type_object_get_size(TypeImpl *ti)
 189 {
 190     if (ti->instance_size) {
 191         return ti->instance_size;
 192     }
 193
 194     if (type_has_parent(ti)) {
 195         return type_object_get_size(type_get_parent(ti));
 196     }
 197
 198     return 0;
 199 }
 200
 201 static void type_class_interface_init(TypeImpl *ti, InterfaceImpl *iface)
 202 {
 203     TypeInfo info = {
 204         .instance_size = sizeof(Interface),
 205         .parent = iface->parent,
 206         .class_size = sizeof(InterfaceClass),
 207         .class_init = iface->interface_initfn,
 208         .abstract = true,
 209     };
 210     char *name = g_strdup_printf("<%s::%s>", ti->name, iface->parent);
 211
 212     info.name = name;
 213     iface->type = type_register_internal(&info);
 214     g_free(name);
 215 }
 216
 217 static void type_initialize(TypeImpl *ti)
 218 {
 219     TypeImpl *parent;
 220     int i;
 221
 222     if (ti->class) {
 223         return;
 224     }
 225
 226     ti->class_size = type_class_get_size(ti);
 227     ti->instance_size = type_object_get_size(ti);
 228
 229     ti->class = g_malloc0(ti->class_size);
 230
 231     parent = type_get_parent(ti);
 232     if (parent) {
 233         type_initialize(parent);
 234
 235         g_assert(parent->class_size <= ti->class_size);
 236         memcpy(ti->class, parent->class, parent->class_size);
 237     }
 238
 239     ti->class->type = ti;
 240
 241     while (parent) {
 242         if (parent->class_base_init) {
 243             parent->class_base_init(ti->class, ti->class_data);
 244         }
 245         parent = type_get_parent(parent);
 246     }
 247
 248     for (i = 0; i < ti->num_interfaces; i++) {
 249         type_class_interface_init(ti, &ti->interfaces[i]);
 250     }
 251
 252     if (ti->class_init) {
 253         ti->class_init(ti->class, ti->class_data);
 254     }
 255 }
 256
 257 static void object_interface_init(Object *obj, InterfaceImpl *iface)
 258 {
 259     TypeImpl *ti = iface->type;
 260     Interface *iface_obj;
 261
 262     iface_obj = INTERFACE(object_new(ti->name));
 263     iface_obj->obj = obj;
 264
 265     obj->interfaces = g_slist_prepend(obj->interfaces, iface_obj);
 266 }
 267
 268 static void object_init_with_type(Object *obj, TypeImpl *ti)
 269 {
 270     int i;
 271
 272     if (type_has_parent(ti)) {
 273         object_init_with_type(obj, type_get_parent(ti));
 274     }
 275
 276     for (i = 0; i < ti->num_interfaces; i++) {
 277         object_interface_init(obj, &ti->interfaces[i]);
 278     }
 279
 280     if (ti->instance_init) {
 281         ti->instance_init(obj);
 282     }
 283 }
 284
 285 void object_initialize_with_type(void *data, TypeImpl *type)
 286 {
 287     Object *obj = data;
 288
 289     g_assert(type != NULL);
 290     type_initialize(type);
 291
 292     g_assert(type->instance_size >= sizeof(Object));
 293     g_assert(type->abstract == false);
 294
 295     memset(obj, 0, type->instance_size);
 296     obj->class = type->class;
 297     QTAILQ_INIT(&obj->properties);
 298     object_init_with_type(obj, type);
 299 }
 300
 301 void object_initialize(void *data, const char *typename)
 302 {
 303     TypeImpl *type = type_get_by_name(typename);
 304
 305     object_initialize_with_type(data, type);
 306 }
 307
 308 static inline bool object_property_is_child(ObjectProperty *prop)
 309 {
 310     return strstart(prop->type, "child<", NULL);
 311 }
 312
 313 static inline bool object_property_is_link(ObjectProperty *prop)
 314 {
 315     return strstart(prop->type, "link<", NULL);
 316 }
 317
 318 static void object_property_del_all(Object *obj)
 319 {
 320     while (!QTAILQ_EMPTY(&obj->properties)) {
 321         ObjectProperty *prop = QTAILQ_FIRST(&obj->properties);
 322
 323         QTAILQ_REMOVE(&obj->properties, prop, node);
 324
 325         if (prop->release) {
 326             prop->release(obj, prop->name, prop->opaque);
 327         }
 328
 329         g_free(prop->name);
 330         g_free(prop->type);
 331         g_free(prop);
 332     }
 333 }
 334
 335 static void object_property_del_child(Object *obj, Object *child, Error **errp)
 336 {
 337     ObjectProperty *prop;
 338
 339     QTAILQ_FOREACH(prop, &obj->properties, node) {
 340         if (object_property_is_child(prop) && prop->opaque == child) {
 341             object_property_del(obj, prop->name, errp);
 342             break;
 343         }
 344     }
 345 }
 346
 347 void object_unparent(Object *obj)
 348 {
 349     if (obj->parent) {
 350         object_property_del_child(obj->parent, obj, NULL);
 351     }
 352 }
 353
 354 static void object_deinit(Object *obj, TypeImpl *type)
 355 {
 356     if (type->instance_finalize) {
 357         type->instance_finalize(obj);
 358     }
 359
 360     while (obj->interfaces) {
 361         Interface *iface_obj = obj->interfaces->data;
 362         obj->interfaces = g_slist_delete_link(obj->interfaces, obj->interfaces);
 363         object_delete(OBJECT(iface_obj));
 364     }
 365
 366     if (type_has_parent(type)) {
 367         object_deinit(obj, type_get_parent(type));
 368     }
 369
 370     object_unparent(obj);
 371 }
 372
 373 void object_finalize(void *data)
 374 {
 375     Object *obj = data;
 376     TypeImpl *ti = obj->class->type;
 377
 378     object_deinit(obj, ti);
 379     object_property_del_all(obj);
 380
 381     g_assert(obj->ref == 0);
 382 }
 383
 384 Object *object_new_with_type(Type type)
 385 {
 386     Object *obj;
 387
 388     g_assert(type != NULL);
 389     type_initialize(type);
 390
 391     obj = g_malloc(type->instance_size);
 392     object_initialize_with_type(obj, type);
 393     object_ref(obj);
 394
 395     return obj;
 396 }
 397
 398 Object *object_new(const char *typename)
 399 {
 400     TypeImpl *ti = type_get_by_name(typename);
 401
 402     return object_new_with_type(ti);
 403 }
 404
 405 void object_delete(Object *obj)
 406 {
 407     object_unref(obj);
 408     g_assert(obj->ref == 0);
 409     g_free(obj);
 410 }
 411
 412 static bool type_is_ancestor(TypeImpl *type, TypeImpl *target_type)
 413 {
 414     assert(target_type);
 415
 416     /* Check if typename is a direct ancestor of type */
 417     while (type) {
 418         if (type == target_type) {
 419             return true;
 420         }
 421
 422         type = type_get_parent(type);
 423     }
 424
 425     return false;
 426 }
 427
 428 static bool object_is_type(Object *obj, TypeImpl *target_type)
 429 {
 430     return !target_type || type_is_ancestor(obj->class->type, target_type);
 431 }
 432
 433 Object *object_dynamic_cast(Object *obj, const char *typename)
 434 {
 435     TypeImpl *target_type = type_get_by_name(typename);
 436     GSList *i;
 437
 438     /* Check if typename is a direct ancestor.  Special-case TYPE_OBJECT,
 439      * we want to go back from interfaces to the parent.
 440     */
 441     if (target_type && object_is_type(obj, target_type)) {
 442         return obj;
 443     }
 444
 445     /* Check if obj is an interface and its containing object is a direct
 446      * ancestor of typename.  In principle we could do this test at the very
 447      * beginning of object_dynamic_cast, avoiding a second call to
 448      * object_is_type.  However, casting between interfaces is relatively
 449      * rare, and object_is_type(obj, type_interface) would fail almost always.
 450      *
 451      * Perhaps we could add a magic value to the object header for increased
 452      * (run-time) type safety and to speed up tests like this one.  If we ever
 453      * do that we can revisit the order here.
 454      */
 455     if (object_is_type(obj, type_interface)) {
 456         assert(!obj->interfaces);
 457         obj = INTERFACE(obj)->obj;
 458         if (object_is_type(obj, target_type)) {
 459             return obj;
 460         }
 461     }
 462
 463     if (!target_type) {
 464         return obj;
 465     }
 466
 467     /* Check if obj has an interface of typename */
 468     for (i = obj->interfaces; i; i = i->next) {
 469         Interface *iface = i->data;
 470
 471         if (object_is_type(OBJECT(iface), target_type)) {
 472             return OBJECT(iface);
 473         }
 474     }
 475
 476     return NULL;
 477 }
 478
 479
 480 Object *object_dynamic_cast_assert(Object *obj, const char *typename)
 481 {
 482     Object *inst;
 483
 484     inst = object_dynamic_cast(obj, typename);
 485
 486     if (!inst) {
 487         fprintf(stderr, "Object %p is not an instance of type %s\n",
 488                 obj, typename);
 489         abort();
 490     }
 491
 492     return inst;
 493 }
 494
 495 ObjectClass *object_class_dynamic_cast(ObjectClass *class,
 496                                        const char *typename)
 497 {
 498     TypeImpl *target_type = type_get_by_name(typename);
 499     TypeImpl *type = class->type;
 500
 501     while (type) {
 502         if (type == target_type) {
 503             return class;
 504         }
 505
 506         type = type_get_parent(type);
 507     }
 508
 509     return NULL;
 510 }
 511
 512 ObjectClass *object_class_dynamic_cast_assert(ObjectClass *class,
 513                                               const char *typename)
 514 {
 515     ObjectClass *ret = object_class_dynamic_cast(class, typename);
 516
 517     if (!ret) {
 518         fprintf(stderr, "Object %p is not an instance of type %s\n",
 519                 class, typename);
 520         abort();
 521     }
 522
 523     return ret;
 524 }
 525
 526 const char *object_get_typename(Object *obj)
 527 {
 528     return obj->class->type->name;
 529 }
 530
 531 ObjectClass *object_get_class(Object *obj)
 532 {
 533     return obj->class;
 534 }
 535
 536 const char *object_class_get_name(ObjectClass *klass)
 537 {
 538     return klass->type->name;
 539 }
 540
 541 ObjectClass *object_class_by_name(const char *typename)
 542 {
 543     TypeImpl *type = type_get_by_name(typename);
 544
 545     if (!type) {
 546         return NULL;
 547     }
 548
 549     type_initialize(type);
 550
 551     return type->class;
 552 }
 553
 554 ObjectClass *object_class_get_parent(ObjectClass *class)
 555 {
 556     TypeImpl *type = type_get_parent(class->type);
 557
 558     if (!type) {
 559         return NULL;
 560     }
 561
 562     type_initialize(type);
 563
 564     return type->class;
 565 }
 566
 567 typedef struct OCFData
 568 {
 569     void (*fn)(ObjectClass *klass, void *opaque);
 570     const char *implements_type;
 571     bool include_abstract;
 572     void *opaque;
 573 } OCFData;
 574
 575 static void object_class_foreach_tramp(gpointer key, gpointer value,
 576                                        gpointer opaque)
 577 {
 578     OCFData *data = opaque;
 579     TypeImpl *type = value;
 580     ObjectClass *k;
 581
 582     type_initialize(type);
 583     k = type->class;
 584
 585     if (!data->include_abstract && type->abstract) {
 586         return;
 587     }
 588
 589     if (data->implements_type &&
 590         !object_class_dynamic_cast(k, data->implements_type)) {
 591         return;
 592     }
 593
 594     data->fn(k, data->opaque);
 595 }
 596
 597 void object_class_foreach(void (*fn)(ObjectClass *klass, void *opaque),
 598                           const char *implements_type, bool include_abstract,
 599                           void *opaque)
 600 {
 601     OCFData data = { fn, implements_type, include_abstract, opaque };
 602
 603     g_hash_table_foreach(type_table_get(), object_class_foreach_tramp, &data);
 604 }
 605
 606 int object_child_foreach(Object *obj, int (*fn)(Object *child, void *opaque),
 607                          void *opaque)
 608 {
 609     ObjectProperty *prop;
 610     int ret = 0;
 611
 612     QTAILQ_FOREACH(prop, &obj->properties, node) {
 613         if (object_property_is_child(prop)) {
 614             ret = fn(prop->opaque, opaque);
 615             if (ret != 0) {
 616                 break;
 617             }
 618         }
 619     }
 620     return ret;
 621 }
 622
 623 static void object_class_get_list_tramp(ObjectClass *klass, void *opaque)
 624 {
 625     GSList **list = opaque;
 626
 627     *list = g_slist_prepend(*list, klass);
 628 }
 629
 630 GSList *object_class_get_list(const char *implements_type,
 631                               bool include_abstract)
 632 {
 633     GSList *list = NULL;
 634
 635     object_class_foreach(object_class_get_list_tramp,
 636                          implements_type, include_abstract, &list);
 637     return list;
 638 }
 639
 640 void object_ref(Object *obj)
 641 {
 642     obj->ref++;
 643 }
 644
 645 void object_unref(Object *obj)
 646 {
 647     g_assert(obj->ref > 0);
 648     obj->ref--;
 649
 650     /* parent always holds a reference to its children */
 651     if (obj->ref == 0) {
 652         object_finalize(obj);
 653     }
 654 }
 655
 656 void object_property_add(Object *obj, const char *name, const char *type,
 657                          ObjectPropertyAccessor *get,
 658                          ObjectPropertyAccessor *set,
 659                          ObjectPropertyRelease *release,
 660                          void *opaque, Error **errp)
 661 {
 662     ObjectProperty *prop = g_malloc0(sizeof(*prop));
 663
 664     prop->name = g_strdup(name);
 665     prop->type = g_strdup(type);
 666
 667     prop->get = get;
 668     prop->set = set;
 669     prop->release = release;
 670     prop->opaque = opaque;
 671
 672     QTAILQ_INSERT_TAIL(&obj->properties, prop, node);
 673 }
 674
 675 ObjectProperty *object_property_find(Object *obj, const char *name,
 676                                      Error **errp)
 677 {
 678     ObjectProperty *prop;
 679
 680     QTAILQ_FOREACH(prop, &obj->properties, node) {
 681         if (strcmp(prop->name, name) == 0) {
 682             return prop;
 683         }
 684     }
 685
 686     error_set(errp, QERR_PROPERTY_NOT_FOUND, "", name);
 687     return NULL;
 688 }
 689
 690 void object_property_del(Object *obj, const char *name, Error **errp)
 691 {
 692     ObjectProperty *prop = object_property_find(obj, name, errp);
 693     if (prop == NULL) {
 694         return;
 695     }
 696
 697     if (prop->release) {
 698         prop->release(obj, name, prop->opaque);
 699     }
 700
 701     QTAILQ_REMOVE(&obj->properties, prop, node);
 702
 703     g_free(prop->name);
 704     g_free(prop->type);
 705     g_free(prop);
 706 }
 707
 708 void object_property_get(Object *obj, Visitor *v, const char *name,
 709                          Error **errp)
 710 {
 711     ObjectProperty *prop = object_property_find(obj, name, errp);
 712     if (prop == NULL) {
 713         return;
 714     }
 715
 716     if (!prop->get) {
 717         error_set(errp, QERR_PERMISSION_DENIED);
 718     } else {
 719         prop->get(obj, v, prop->opaque, name, errp);
 720     }
 721 }
 722
 723 void object_property_set(Object *obj, Visitor *v, const char *name,
 724                          Error **errp)
 725 {
 726     ObjectProperty *prop = object_property_find(obj, name, errp);
 727     if (prop == NULL) {
 728         return;
 729     }
 730
 731     if (!prop->set) {
 732         error_set(errp, QERR_PERMISSION_DENIED);
 733     } else {
 734         prop->set(obj, v, prop->opaque, name, errp);
 735     }
 736 }
 737
 738 void object_property_set_str(Object *obj, const char *value,
 739                              const char *name, Error **errp)
 740 {
 741     QString *qstr = qstring_from_str(value);
 742     object_property_set_qobject(obj, QOBJECT(qstr), name, errp);
 743
 744     QDECREF(qstr);
 745 }
 746
 747 char *object_property_get_str(Object *obj, const char *name,
 748                               Error **errp)
 749 {
 750     QObject *ret = object_property_get_qobject(obj, name, errp);
 751     QString *qstring;
 752     char *retval;
 753
 754     if (!ret) {
 755         return NULL;
 756     }
 757     qstring = qobject_to_qstring(ret);
 758     if (!qstring) {
 759         error_set(errp, QERR_INVALID_PARAMETER_TYPE, name, "string");
 760         retval = NULL;
 761     } else {
 762         retval = g_strdup(qstring_get_str(qstring));
 763     }
 764
 765     QDECREF(qstring);
 766     return retval;
 767 }
 768
 769 void object_property_set_link(Object *obj, Object *value,
 770                               const char *name, Error **errp)
 771 {
 772     object_property_set_str(obj, object_get_canonical_path(value),
 773                             name, errp);
 774 }
 775
 776 Object *object_property_get_link(Object *obj, const char *name,
 777                                  Error **errp)
 778 {
 779     char *str = object_property_get_str(obj, name, errp);
 780     Object *target = NULL;
 781
 782     if (str && *str) {
 783         target = object_resolve_path(str, NULL);
 784         if (!target) {
 785             error_set(errp, QERR_DEVICE_NOT_FOUND, str);
 786         }
 787     }
 788
 789     g_free(str);
 790     return target;
 791 }
 792
 793 void object_property_set_bool(Object *obj, bool value,
 794                               const char *name, Error **errp)
 795 {
 796     QBool *qbool = qbool_from_int(value);
 797     object_property_set_qobject(obj, QOBJECT(qbool), name, errp);
 798
 799     QDECREF(qbool);
 800 }
 801
 802 bool object_property_get_bool(Object *obj, const char *name,
 803                               Error **errp)
 804 {
 805     QObject *ret = object_property_get_qobject(obj, name, errp);
 806     QBool *qbool;
 807     bool retval;
 808
 809     if (!ret) {
 810         return false;
 811     }
 812     qbool = qobject_to_qbool(ret);
 813     if (!qbool) {
 814         error_set(errp, QERR_INVALID_PARAMETER_TYPE, name, "boolean");
 815         retval = false;
 816     } else {
 817         retval = qbool_get_int(qbool);
 818     }
 819
 820     QDECREF(qbool);
 821     return retval;
 822 }
 823
 824 void object_property_set_int(Object *obj, int64_t value,
 825                              const char *name, Error **errp)
 826 {
 827     QInt *qint = qint_from_int(value);
 828     object_property_set_qobject(obj, QOBJECT(qint), name, errp);
 829
 830     QDECREF(qint);
 831 }
 832
 833 int64_t object_property_get_int(Object *obj, const char *name,
 834                                 Error **errp)
 835 {
 836     QObject *ret = object_property_get_qobject(obj, name, errp);
 837     QInt *qint;
 838     int64_t retval;
 839
 840     if (!ret) {
 841         return -1;
 842     }
 843     qint = qobject_to_qint(ret);
 844     if (!qint) {
 845         error_set(errp, QERR_INVALID_PARAMETER_TYPE, name, "int");
 846         retval = -1;
 847     } else {
 848         retval = qint_get_int(qint);
 849     }
 850
 851     QDECREF(qint);
 852     return retval;
 853 }
 854
 855 void object_property_parse(Object *obj, const char *string,
 856                            const char *name, Error **errp)
 857 {
 858     StringInputVisitor *mi;
 859     mi = string_input_visitor_new(string);
 860     object_property_set(obj, string_input_get_visitor(mi), name, errp);
 861
 862     string_input_visitor_cleanup(mi);
 863 }
 864
 865 char *object_property_print(Object *obj, const char *name,
 866                             Error **errp)
 867 {
 868     StringOutputVisitor *mo;
 869     char *string;
 870
 871     mo = string_output_visitor_new();
 872     object_property_get(obj, string_output_get_visitor(mo), name, errp);
 873     string = string_output_get_string(mo);
 874     string_output_visitor_cleanup(mo);
 875     return string;
 876 }
 877
 878 const char *object_property_get_type(Object *obj, const char *name, Error **errp)
 879 {
 880     ObjectProperty *prop = object_property_find(obj, name, errp);
 881     if (prop == NULL) {
 882         return NULL;
 883     }
 884
 885     return prop->type;
 886 }
 887
 888 Object *object_get_root(void)
 889 {
 890     static Object *root;
 891
 892     if (!root) {
 893         root = object_new("container");
 894     }
 895
 896     return root;
 897 }
 898
 899 static void object_get_child_property(Object *obj, Visitor *v, void *opaque,
 900                                       const char *name, Error **errp)
 901 {
 902     Object *child = opaque;
 903     gchar *path;
 904
 905     path = object_get_canonical_path(child);
 906     visit_type_str(v, &path, name, errp);
 907     g_free(path);
 908 }
 909
 910 static void object_finalize_child_property(Object *obj, const char *name,
 911                                            void *opaque)
 912 {
 913     Object *child = opaque;
 914
 915     object_unref(child);
 916 }
 917
 918 void object_property_add_child(Object *obj, const char *name,
 919                                Object *child, Error **errp)
 920 {
 921     gchar *type;
 922
 923     /* Registering an interface object in the composition tree will mightily
 924      * confuse object_get_canonical_path (which, on the other hand, knows how
 925      * to get the canonical path of an interface object).
 926      */
 927     assert(!object_is_type(obj, type_interface));
 928
 929     type = g_strdup_printf("child<%s>", object_get_typename(OBJECT(child)));
 930
 931     object_property_add(obj, name, type, object_get_child_property,
 932                         NULL, object_finalize_child_property, child, errp);
 933
 934     object_ref(child);
 935     g_assert(child->parent == NULL);
 936     child->parent = obj;
 937
 938     g_free(type);
 939 }
 940
 941 static void object_get_link_property(Object *obj, Visitor *v, void *opaque,
 942                                      const char *name, Error **errp)
 943 {
 944     Object **child = opaque;
 945     gchar *path;
 946
 947     if (*child) {
 948         path = object_get_canonical_path(*child);
 949         visit_type_str(v, &path, name, errp);
 950         g_free(path);
 951     } else {
 952         path = (gchar *)"";
 953         visit_type_str(v, &path, name, errp);
 954     }
 955 }
 956
 957 static void object_set_link_property(Object *obj, Visitor *v, void *opaque,
 958                                      const char *name, Error **errp)
 959 {
 960     Object **child = opaque;
 961     Object *old_target;
 962     bool ambiguous = false;
 963     const char *type;
 964     char *path;
 965     gchar *target_type;
 966
 967     type = object_property_get_type(obj, name, NULL);
 968
 969     visit_type_str(v, &path, name, errp);
 970
 971     old_target = *child;
 972     *child = NULL;
 973
 974     if (strcmp(path, "") != 0) {
 975         Object *target;
 976
 977         /* Go from link<FOO> to FOO.  */
 978         target_type = g_strndup(&type[5], strlen(type) - 6);
 979         target = object_resolve_path_type(path, target_type, &ambiguous);
 980
 981         if (ambiguous) {
 982             error_set(errp, QERR_AMBIGUOUS_PATH, path);
 983         } else if (target) {
 984             object_ref(target);
 985             *child = target;
 986         } else {
 987             target = object_resolve_path(path, &ambiguous);
 988             if (target || ambiguous) {
 989                 error_set(errp, QERR_INVALID_PARAMETER_TYPE, name, target_type);
 990             } else {
 991                 error_set(errp, QERR_DEVICE_NOT_FOUND, path);
 992             }
 993         }
 994         g_free(target_type);
 995     }
 996
 997     g_free(path);
 998
 999     if (old_target != NULL) {
1000         object_unref(old_target);
1001     }
1002 }
1003
1004 void object_property_add_link(Object *obj, const char *name,
1005                               const char *type, Object **child,
1006                               Error **errp)
1007 {
1008     gchar *full_type;
1009
1010     full_type = g_strdup_printf("link<%s>", type);
1011
1012     object_property_add(obj, name, full_type,
1013                         object_get_link_property,
1014                         object_set_link_property,
1015                         NULL, child, errp);
1016
1017     g_free(full_type);
1018 }
1019
1020 gchar *object_get_canonical_path(Object *obj)
1021 {
1022     Object *root = object_get_root();
1023     char *newpath = NULL, *path = NULL;
1024
1025     if (object_is_type(obj, type_interface)) {
1026         obj = INTERFACE(obj)->obj;
1027     }
1028
1029     while (obj != root) {
1030         ObjectProperty *prop = NULL;
1031
1032         g_assert(obj->parent != NULL);
1033
1034         QTAILQ_FOREACH(prop, &obj->parent->properties, node) {
1035             if (!object_property_is_child(prop)) {
1036                 continue;
1037             }
1038
1039             if (prop->opaque == obj) {
1040                 if (path) {
1041                     newpath = g_strdup_printf("%s/%s", prop->name, path);
1042                     g_free(path);
1043                     path = newpath;
1044                 } else {
1045                     path = g_strdup(prop->name);
1046                 }
1047                 break;
1048             }
1049         }
1050
1051         g_assert(prop != NULL);
1052
1053         obj = obj->parent;
1054     }
1055
1056     newpath = g_strdup_printf("/%s", path);
1057     g_free(path);
1058
1059     return newpath;
1060 }
1061
1062 Object *object_resolve_path_component(Object *parent, gchar *part)
1063 {
1064     ObjectProperty *prop = object_property_find(parent, part, NULL);
1065     if (prop == NULL) {
1066         return NULL;
1067     }
1068
1069     if (object_property_is_link(prop)) {
1070         return *(Object **)prop->opaque;
1071     } else if (object_property_is_child(prop)) {
1072         return prop->opaque;
1073     } else {
1074         return NULL;
1075     }
1076 }
1077
1078 static Object *object_resolve_abs_path(Object *parent,
1079                                           gchar **parts,
1080                                           const char *typename,
1081                                           int index)
1082 {
1083     Object *child;
1084
1085     if (parts[index] == NULL) {
1086         return object_dynamic_cast(parent, typename);
1087     }
1088
1089     if (strcmp(parts[index], "") == 0) {
1090         return object_resolve_abs_path(parent, parts, typename, index + 1);
1091     }
1092
1093     child = object_resolve_path_component(parent, parts[index]);
1094     if (!child) {
1095         return NULL;
1096     }
1097
1098     return object_resolve_abs_path(child, parts, typename, index + 1);
1099 }
1100
1101 static Object *object_resolve_partial_path(Object *parent,
1102                                               gchar **parts,
1103                                               const char *typename,
1104                                               bool *ambiguous)
1105 {
1106     Object *obj;
1107     ObjectProperty *prop;
1108
1109     obj = object_resolve_abs_path(parent, parts, typename, 0);
1110
1111     QTAILQ_FOREACH(prop, &parent->properties, node) {
1112         Object *found;
1113
1114         if (!object_property_is_child(prop)) {
1115             continue;
1116         }
1117
1118         found = object_resolve_partial_path(prop->opaque, parts,
1119                                             typename, ambiguous);
1120         if (found) {
1121             if (obj) {
1122                 if (ambiguous) {
1123                     *ambiguous = true;
1124                 }
1125                 return NULL;
1126             }
1127             obj = found;
1128         }
1129
1130         if (ambiguous && *ambiguous) {
1131             return NULL;
1132         }
1133     }
1134
1135     return obj;
1136 }
1137
1138 Object *object_resolve_path_type(const char *path, const char *typename,
1139                                  bool *ambiguous)
1140 {
1141     bool partial_path = true;
1142     Object *obj;
1143     gchar **parts;
1144
1145     parts = g_strsplit(path, "/", 0);
1146     if (parts == NULL || parts[0] == NULL) {
1147         g_strfreev(parts);
1148         return object_get_root();
1149     }
1150
1151     if (strcmp(parts[0], "") == 0) {
1152         partial_path = false;
1153     }
1154
1155     if (partial_path) {
1156         if (ambiguous) {
1157             *ambiguous = false;
1158         }
1159         obj = object_resolve_partial_path(object_get_root(), parts,
1160                                           typename, ambiguous);
1161     } else {
1162         obj = object_resolve_abs_path(object_get_root(), parts, typename, 1);
1163     }
1164
1165     g_strfreev(parts);
1166
1167     return obj;
1168 }
1169
1170 Object *object_resolve_path(const char *path, bool *ambiguous)
1171 {
1172     return object_resolve_path_type(path, TYPE_OBJECT, ambiguous);
1173 }
1174
1175 typedef struct StringProperty
1176 {
1177     char *(*get)(Object *, Error **);
1178     void (*set)(Object *, const char *, Error **);
1179 } StringProperty;
1180
1181 static void property_get_str(Object *obj, Visitor *v, void *opaque,
1182                              const char *name, Error **errp)
1183 {
1184     StringProperty *prop = opaque;
1185     char *value;
1186
1187     value = prop->get(obj, errp);
1188     if (value) {
1189         visit_type_str(v, &value, name, errp);
1190         g_free(value);
1191     }
1192 }
1193
1194 static void property_set_str(Object *obj, Visitor *v, void *opaque,
1195                              const char *name, Error **errp)
1196 {
1197     StringProperty *prop = opaque;
1198     char *value;
1199     Error *local_err = NULL;
1200
1201     visit_type_str(v, &value, name, &local_err);
1202     if (local_err) {
1203         error_propagate(errp, local_err);
1204         return;
1205     }
1206
1207     prop->set(obj, value, errp);
1208     g_free(value);
1209 }
1210
1211 static void property_release_str(Object *obj, const char *name,
1212                                  void *opaque)
1213 {
1214     StringProperty *prop = opaque;
1215     g_free(prop);
1216 }
1217
1218 void object_property_add_str(Object *obj, const char *name,
1219                            char *(*get)(Object *, Error **),
1220                            void (*set)(Object *, const char *, Error **),
1221                            Error **errp)
1222 {
1223     StringProperty *prop = g_malloc0(sizeof(*prop));
1224
1225     prop->get = get;
1226     prop->set = set;
1227
1228     object_property_add(obj, name, "string",
1229                         get ? property_get_str : NULL,
1230                         set ? property_set_str : NULL,
1231                         property_release_str,
1232                         prop, errp);
1233 }
1234
1235 static char *qdev_get_type(Object *obj, Error **errp)
1236 {
1237     return g_strdup(object_get_typename(obj));
1238 }
1239
1240 static void object_instance_init(Object *obj)
1241 {
1242     object_property_add_str(obj, "type", qdev_get_type, NULL, NULL);
1243 }
1244
1245 static void register_types(void)
1246 {
1247     static TypeInfo interface_info = {
1248         .name = TYPE_INTERFACE,
1249         .instance_size = sizeof(Interface),
1250         .abstract = true,
1251     };
1252
1253     static TypeInfo object_info = {
1254         .name = TYPE_OBJECT,
1255         .instance_size = sizeof(Object),
1256         .instance_init = object_instance_init,
1257         .abstract = true,
1258     };
1259
1260     type_interface = type_register_internal(&interface_info);
1261     type_register_internal(&object_info);
1262 }
1263
1264 type_init(register_types)