zend_lazy_objects.c

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/*
   +----------------------------------------------------------------------+
   | Zend Engine                                                          |
   +----------------------------------------------------------------------+
   | Copyright (c) Zend Technologies Ltd. (http://www.zend.com)           |
   +----------------------------------------------------------------------+
   | This source file is subject to version 2.00 of the Zend license,     |
   | that is bundled with this package in the file LICENSE, and is        |
   | available through the world-wide-web at the following url:           |
   | http://www.zend.com/license/2_00.txt.                                |
   | If you did not receive a copy of the Zend license and are unable to  |
   | obtain it through the world-wide-web, please send a note to          |
   | license@zend.com so we can mail you a copy immediately.              |
   +----------------------------------------------------------------------+
   | Authors: Arnaud Le Blanc <arnaud.lb@gmail.com>                       |
   +----------------------------------------------------------------------+
*/
 
/* Lazy objects are standard zend_object whose initialization is deferred until
 * one of their properties backing store is accessed for the first time.
 *
 * This is implemented by using the same fallback mechanism as __get and __set
 * magic methods that is triggered when an undefined property is accessed.
 *
 * Execution of methods or virtual property hooks do not trigger initialization
 * until they access properties.
 *
 * A lazy object can be created via the Reflection API. The user specifies an
 * initializer function that is called when initialization is required.
 *
 * There are two kinds of lazy objects:
 *
 * - Ghosts: These are initialized in-place by the initializer function
 * - Proxy: The initializer returns a new instance. After initialization,
 *   interaction with the proxy object are proxied to the instance.
 *
 * Internal objects are not supported.
 */
 
#include "zend_API.h"
#include "zend_compile.h"
#include "zend_execute.h"
#include "zend_gc.h"
#include "zend_hash.h"
#include "zend_object_handlers.h"
#include "zend_objects_API.h"
#include "zend_operators.h"
#include "zend_types.h"
#include "zend_variables.h"
#include "zend_lazy_objects.h"

typedef struct _zend_lazy_object_info {
    union {
        struct {
            zend_fcall_info_cache fcc;
            zval zv; /* ReflectionClass::getLazyInitializer() */
        } initializer;
        zend_object *instance; /* For initialized lazy proxy objects */
    } u;
    zend_lazy_object_flags_t flags;
    int lazy_properties_count;
} zend_lazy_object_info;
 
/* zend_hash dtor_func_t for zend_lazy_objects_store.infos */
static void zend_lazy_object_info_dtor_func(zval *pElement)
{
    zend_lazy_object_info *info = (zend_lazy_object_info*) Z_PTR_P(pElement);
 
    if (info->flags & ZEND_LAZY_OBJECT_INITIALIZED) {
        ZEND_ASSERT(info->flags & ZEND_LAZY_OBJECT_STRATEGY_PROXY);
        zend_object_release(info->u.instance);
    } else {
        zval_ptr_dtor(&info->u.initializer.zv);
        zend_fcc_dtor(&info->u.initializer.fcc);
    }
 
    efree(info);
}
 
void zend_lazy_objects_init(zend_lazy_objects_store *store)
{
    zend_hash_init(&store->infos, 8, NULL, zend_lazy_object_info_dtor_func, false);
}
 
void zend_lazy_objects_destroy(zend_lazy_objects_store *store)
{
    ZEND_ASSERT(zend_hash_num_elements(&store->infos) == 0 || CG(unclean_shutdown));
    zend_hash_destroy(&store->infos);
}
 
static void zend_lazy_object_set_info(zend_object *obj, zend_lazy_object_info *info)
{
    ZEND_ASSERT(zend_object_is_lazy(obj));
 
    zval *zv = zend_hash_index_add_new_ptr(&EG(lazy_objects_store).infos, obj->handle, info);
    ZEND_ASSERT(zv);
    (void)zv;
}
 
static zend_lazy_object_info* zend_lazy_object_get_info(zend_object *obj)
{
    ZEND_ASSERT(zend_object_is_lazy(obj));
 
    zend_lazy_object_info *info = zend_hash_index_find_ptr(&EG(lazy_objects_store).infos, obj->handle);
    ZEND_ASSERT(info);
 
    return info;
}
 
static bool zend_lazy_object_has_stale_info(zend_object *obj)
{
    return zend_hash_index_find_ptr(&EG(lazy_objects_store).infos, obj->handle);
}
 
zval* zend_lazy_object_get_initializer_zv(zend_object *obj)
{
    ZEND_ASSERT(!zend_lazy_object_initialized(obj));
 
    zend_lazy_object_info *info = zend_lazy_object_get_info(obj);
 
    ZEND_ASSERT(!(info->flags & ZEND_LAZY_OBJECT_INITIALIZED));
 
    return &info->u.initializer.zv;
}
 
static zend_fcall_info_cache* zend_lazy_object_get_initializer_fcc(zend_object *obj)
{
    ZEND_ASSERT(!zend_lazy_object_initialized(obj));
 
    zend_lazy_object_info *info = zend_lazy_object_get_info(obj);
 
    ZEND_ASSERT(!(info->flags & ZEND_LAZY_OBJECT_INITIALIZED));
 
    return &info->u.initializer.fcc;
}
 
zend_object* zend_lazy_object_get_instance(zend_object *obj)
{
    ZEND_ASSERT(zend_lazy_object_initialized(obj));
 
    if (zend_object_is_lazy_proxy(obj)) {
        zend_lazy_object_info *info = zend_lazy_object_get_info(obj);
 
        ZEND_ASSERT(info->flags & ZEND_LAZY_OBJECT_INITIALIZED);
 
        return info->u.instance;
    }
 
    return obj;
}
 
zend_lazy_object_flags_t zend_lazy_object_get_flags(zend_object *obj)
{
    return zend_lazy_object_get_info(obj)->flags;
}
 
void zend_lazy_object_del_info(zend_object *obj)
{
    zend_result res = zend_hash_index_del(&EG(lazy_objects_store).infos, obj->handle);
    ZEND_ASSERT(res == SUCCESS);
}
 
bool zend_lazy_object_decr_lazy_props(zend_object *obj)
{
    ZEND_ASSERT(zend_object_is_lazy(obj));
    ZEND_ASSERT(!zend_lazy_object_initialized(obj));
 
    zend_lazy_object_info *info = zend_lazy_object_get_info(obj);
 
    ZEND_ASSERT(info->lazy_properties_count > 0);
 
    info->lazy_properties_count--;
 
    return info->lazy_properties_count == 0;
}

 
ZEND_API bool zend_class_can_be_lazy(zend_class_entry *ce)
{
    /* Internal classes are not supported */
    if (UNEXPECTED(ce->type == ZEND_INTERNAL_CLASS && ce != zend_standard_class_def)) {
        return false;
    }
 
    for (zend_class_entry *parent = ce->parent; parent; parent = parent->parent) {
        if (UNEXPECTED(parent->type == ZEND_INTERNAL_CLASS && parent != zend_standard_class_def)) {
            return false;
        }
    }
 
    return true;
}
 
static int zlo_hash_remove_dyn_props_func(zval *pDest)
{
    if (Z_TYPE_P(pDest) == IS_INDIRECT) {
        return ZEND_HASH_APPLY_STOP;
    }
 
    return ZEND_HASH_APPLY_REMOVE;
}
 
static bool zlo_is_iterating(zend_object *object)
{
    if (object->properties && HT_ITERATORS_COUNT(object->properties)) {
        return true;
    }
    if (zend_object_is_lazy_proxy(object)
            && zend_lazy_object_initialized(object)) {
        return zlo_is_iterating(zend_lazy_object_get_instance(object));
    }
    return false;
}
 
/* Make object 'obj' lazy. If 'obj' is NULL, create a lazy instance of
 * class 'reflection_ce' */
ZEND_API zend_object *zend_object_make_lazy(zend_object *obj,
        zend_class_entry *reflection_ce, zval *initializer_zv,
        zend_fcall_info_cache *initializer_fcc, zend_lazy_object_flags_t flags)
{
    ZEND_ASSERT(!(flags & ~(ZEND_LAZY_OBJECT_USER_MASK|ZEND_LAZY_OBJECT_STRATEGY_MASK)));
    ZEND_ASSERT((flags & ZEND_LAZY_OBJECT_STRATEGY_MASK) == ZEND_LAZY_OBJECT_STRATEGY_GHOST
            || (flags & ZEND_LAZY_OBJECT_STRATEGY_MASK) == ZEND_LAZY_OBJECT_STRATEGY_PROXY);
 
    ZEND_ASSERT(!obj || (!zend_object_is_lazy(obj) || zend_lazy_object_initialized(obj)));
    ZEND_ASSERT(!obj || instanceof_function(obj->ce, reflection_ce));
 
    /* Internal classes are not supported */
    if (UNEXPECTED(reflection_ce->type == ZEND_INTERNAL_CLASS && reflection_ce != zend_standard_class_def)) {
        zend_throw_error(NULL, "Cannot make instance of internal class lazy: %s is internal", ZSTR_VAL(reflection_ce->name));
        return NULL;
    }
 
    for (zend_class_entry *parent = reflection_ce->parent; parent; parent = parent->parent) {
        if (UNEXPECTED(parent->type == ZEND_INTERNAL_CLASS && parent != zend_standard_class_def)) {
            zend_throw_error(NULL, "Cannot make instance of internal class lazy: %s inherits internal class %s",
                ZSTR_VAL(reflection_ce->name), ZSTR_VAL(parent->name));
            return NULL;
        }
    }
 
    int lazy_properties_count = 0;
 
    if (!obj) {
        if (UNEXPECTED(reflection_ce->ce_flags & ZEND_ACC_UNINSTANTIABLE)) {
            zval zobj;
            /* Call object_init_ex() for the generated exception */
            zend_result result = object_init_ex(&zobj, reflection_ce);
            ZEND_ASSERT(result == FAILURE && EG(exception));
            (void)result;
            return NULL;
        }
 
        if (UNEXPECTED(!(reflection_ce->ce_flags & ZEND_ACC_CONSTANTS_UPDATED))) {
            if (UNEXPECTED(zend_update_class_constants(reflection_ce) != SUCCESS)) {
                ZEND_ASSERT(EG(exception));
                return NULL;
            }
        }
 
        obj = zend_objects_new(reflection_ce);
 
        /* Iterate in reverse to avoid overriding Z_PROP_FLAG_P() of child props with added hooks (GH-17870). */
        for (int i = obj->ce->default_properties_count - 1; i >= 0; i--) {
            zval *p = &obj->properties_table[i];
            ZVAL_UNDEF(p);
            Z_PROP_FLAG_P(p) = 0;
 
            zend_property_info *prop_info = obj->ce->properties_info_table[i];
            if (prop_info) {
                zval *p = &obj->properties_table[OBJ_PROP_TO_NUM(prop_info->offset)];
                Z_PROP_FLAG_P(p) = IS_PROP_UNINIT | IS_PROP_LAZY;
                lazy_properties_count++;
            }
        }
    } else {
        if (zlo_is_iterating(obj)) {
            zend_throw_error(NULL, "Can not reset an object during property iteration");
            return NULL;
        }
        if (zend_object_is_lazy(obj)) {
            ZEND_ASSERT(zend_object_is_lazy_proxy(obj) && zend_lazy_object_initialized(obj));
            OBJ_EXTRA_FLAGS(obj) &= ~(IS_OBJ_LAZY_UNINITIALIZED|IS_OBJ_LAZY_PROXY);
            zend_lazy_object_del_info(obj);
        } else {
            if (zend_lazy_object_has_stale_info(obj)) {
                zend_throw_error(NULL, "Can not reset an object while it is being initialized");
                return NULL;
            }
 
            if (!(flags & ZEND_LAZY_OBJECT_SKIP_DESTRUCTOR)
                && !(OBJ_FLAGS(obj) & IS_OBJ_DESTRUCTOR_CALLED)) {
                if (obj->handlers->dtor_obj != zend_objects_destroy_object
                        || obj->ce->destructor) {
                    GC_ADD_FLAGS(obj, IS_OBJ_DESTRUCTOR_CALLED);
                    GC_ADDREF(obj);
                    obj->handlers->dtor_obj(obj);
                    GC_DELREF(obj);
                    if (EG(exception)) {
                        return NULL;
                    }
                }
            }
        }
 
        GC_DEL_FLAGS(obj, IS_OBJ_DESTRUCTOR_CALLED);
 
        /* unset() dynamic properties. Do not NULL out obj->properties, as this
         * would be unexpected. */
        if (obj->properties) {
            if (UNEXPECTED(GC_REFCOUNT(obj->properties) > 1)) {
                if (EXPECTED(!(GC_FLAGS(obj->properties) & IS_ARRAY_IMMUTABLE))) {
                    GC_DELREF(obj->properties);
                }
                obj->properties = zend_array_dup(obj->properties);
            }
            zend_hash_reverse_apply(obj->properties, zlo_hash_remove_dyn_props_func);
        }
 
        /* unset() declared properties */
        for (int i = 0; i < reflection_ce->default_properties_count; i++) {
            zend_property_info *prop_info = obj->ce->properties_info_table[i];
            if (EXPECTED(prop_info)) {
                zval *p = &obj->properties_table[OBJ_PROP_TO_NUM(prop_info->offset)];
                if (Z_TYPE_P(p) != IS_UNDEF) {
                    if ((prop_info->flags & ZEND_ACC_READONLY) && !(Z_PROP_FLAG_P(p) & IS_PROP_REINITABLE)
                            /* TODO: test final property */
                            && ((obj->ce->ce_flags & ZEND_ACC_FINAL) || (prop_info->flags & ZEND_ACC_FINAL))) {
                        continue;
                    }
                    zend_object_dtor_property(obj, p);
                    ZVAL_UNDEF(p);
                }
                Z_PROP_FLAG_P(p) = IS_PROP_UNINIT | IS_PROP_LAZY;
                lazy_properties_count++;
            }
        }
    }
 
    /* Objects become non-lazy if all properties are made non-lazy before
     * initialization is triggered. If the object has no properties to begin
     * with, this happens immediately. */
    if (UNEXPECTED(!lazy_properties_count)) {
        return obj;
    }
 
    OBJ_EXTRA_FLAGS(obj) |= IS_OBJ_LAZY_UNINITIALIZED;
 
    if (flags & ZEND_LAZY_OBJECT_STRATEGY_PROXY) {
        OBJ_EXTRA_FLAGS(obj) |= IS_OBJ_LAZY_PROXY;
    } else {
        ZEND_ASSERT(flags & ZEND_LAZY_OBJECT_STRATEGY_GHOST);
    }
 
    zend_lazy_object_info *info = emalloc(sizeof(*info));
    zend_fcc_dup(&info->u.initializer.fcc, initializer_fcc);
    ZVAL_COPY(&info->u.initializer.zv, initializer_zv);
    info->flags = flags;
    info->lazy_properties_count = lazy_properties_count;
    zend_lazy_object_set_info(obj, info);
 
    return obj;
}

 
/* Mark object as initialized. Lazy properties are initialized to their default
 * value and the initializer is not called. */
ZEND_API zend_object *zend_lazy_object_mark_as_initialized(zend_object *obj)
{
    ZEND_ASSERT(zend_object_is_lazy(obj));
    ZEND_ASSERT(!zend_lazy_object_initialized(obj));
 
    zend_class_entry *ce = obj->ce;
 
    ZEND_ASSERT(ce->ce_flags & ZEND_ACC_CONSTANTS_UPDATED);
 
    zval *default_properties_table = CE_DEFAULT_PROPERTIES_TABLE(ce);
    zval *properties_table = obj->properties_table;
 
    OBJ_EXTRA_FLAGS(obj) &= ~(IS_OBJ_LAZY_UNINITIALIZED|IS_OBJ_LAZY_PROXY);
 
    for (int i = 0; i < ce->default_properties_count; i++) {
        if (Z_PROP_FLAG_P(&properties_table[i]) & IS_PROP_LAZY) {
            ZVAL_COPY_PROP(&properties_table[i], &default_properties_table[i]);
        }
    }
 
    zend_lazy_object_del_info(obj);
 
    return obj;
}
 
/* Revert initializer effects */
static void zend_lazy_object_revert_init(zend_object *obj, zval *properties_table_snapshot, HashTable *properties_snapshot)
{
    zend_class_entry *ce = obj->ce;
 
    if (ce->default_properties_count) {
        ZEND_ASSERT(properties_table_snapshot);
        zval *properties_table = obj->properties_table;
 
        for (int i = 0; i < ce->default_properties_count; i++) {
            zend_property_info *prop_info = ce->properties_info_table[i];
            if (!prop_info) {
                continue;
            }
 
            zval *p = &properties_table[OBJ_PROP_TO_NUM(prop_info->offset)];
            zend_object_dtor_property(obj, p);
            ZVAL_COPY_VALUE_PROP(p, &properties_table_snapshot[OBJ_PROP_TO_NUM(prop_info->offset)]);
 
            if (Z_ISREF_P(p) && ZEND_TYPE_IS_SET(prop_info->type)) {
                ZEND_REF_ADD_TYPE_SOURCE(Z_REF_P(p), prop_info);
            }
        }
 
        efree(properties_table_snapshot);
    }
    if (properties_snapshot) {
        if (obj->properties != properties_snapshot) {
            ZEND_ASSERT((GC_FLAGS(properties_snapshot) & IS_ARRAY_IMMUTABLE) || GC_REFCOUNT(properties_snapshot) >= 1);
            zend_release_properties(obj->properties);
            obj->properties = properties_snapshot;
        } else {
            ZEND_ASSERT((GC_FLAGS(properties_snapshot) & IS_ARRAY_IMMUTABLE) || GC_REFCOUNT(properties_snapshot) > 1);
            zend_release_properties(properties_snapshot);
        }
    } else if (obj->properties) {
        zend_release_properties(obj->properties);
        obj->properties = NULL;
    }
 
    OBJ_EXTRA_FLAGS(obj) |= IS_OBJ_LAZY_UNINITIALIZED;
}
 
static bool zend_lazy_object_compatible(zend_object *real_object, zend_object *lazy_object)
{
    if (EXPECTED(real_object->ce == lazy_object->ce)) {
        return true;
    }
 
    if (!instanceof_function(lazy_object->ce, real_object->ce)) {
        return false;
    }
 
    /* zend_hash_num_elements(ce.properties_info) reports the actual number of
     * properties. ce.default_properties_count is off by the number of property
     * overrides. */
    if (zend_hash_num_elements(&lazy_object->ce->properties_info) != zend_hash_num_elements(&real_object->ce->properties_info)) {
        return false;
    }
 
    return lazy_object->ce->destructor == real_object->ce->destructor
        && lazy_object->ce->clone == real_object->ce->clone;
}
 
/* Initialize a lazy proxy object */
static zend_object *zend_lazy_object_init_proxy(zend_object *obj)
{
    ZEND_ASSERT(zend_object_is_lazy_proxy(obj));
    ZEND_ASSERT(!zend_lazy_object_initialized(obj));
 
    /* Prevent object from being released during initialization */
    GC_ADDREF(obj);
 
    zend_lazy_object_info *info = zend_lazy_object_get_info(obj);
 
    /* prevent reentrant initialization */
    OBJ_EXTRA_FLAGS(obj) &= ~(IS_OBJ_LAZY_UNINITIALIZED|IS_OBJ_LAZY_PROXY);
 
    /* Call factory */
    zval retval;
    int argc = 1;
    zval zobj;
    HashTable *named_params = NULL;
    zend_fcall_info_cache *initializer = &info->u.initializer.fcc;
    zend_object *instance = NULL;
 
    ZVAL_OBJ(&zobj, obj);
 
    zend_call_known_fcc(initializer, &retval, argc, &zobj, named_params);
 
    if (UNEXPECTED(EG(exception))) {
        OBJ_EXTRA_FLAGS(obj) |= IS_OBJ_LAZY_UNINITIALIZED|IS_OBJ_LAZY_PROXY;
        goto exit;
    }
 
    if (UNEXPECTED(Z_TYPE(retval) != IS_OBJECT)) {
        OBJ_EXTRA_FLAGS(obj) |= IS_OBJ_LAZY_UNINITIALIZED|IS_OBJ_LAZY_PROXY;
        zend_type_error("Lazy proxy factory must return an instance of a class compatible with %s, %s returned",
                ZSTR_VAL(obj->ce->name),
                zend_zval_value_name(&retval));
        zval_ptr_dtor(&retval);
        goto exit;
    }
 
    if (UNEXPECTED(Z_TYPE(retval) != IS_OBJECT || !zend_lazy_object_compatible(Z_OBJ(retval), obj))) {
        OBJ_EXTRA_FLAGS(obj) |= IS_OBJ_LAZY_UNINITIALIZED|IS_OBJ_LAZY_PROXY;
        zend_type_error("The real instance class %s is not compatible with the proxy class %s. The proxy must be a instance of the same class as the real instance, or a sub-class with no additional properties, and no overrides of the __destructor or __clone methods.",
                zend_zval_value_name(&retval),
                ZSTR_VAL(obj->ce->name));
        zval_ptr_dtor(&retval);
        goto exit;
    }
 
    if (UNEXPECTED(Z_OBJ(retval) == obj || zend_object_is_lazy(Z_OBJ(retval)))) {
        OBJ_EXTRA_FLAGS(obj) |= IS_OBJ_LAZY_UNINITIALIZED|IS_OBJ_LAZY_PROXY;
        zend_throw_error(NULL, "Lazy proxy factory must return a non-lazy object");
        zval_ptr_dtor(&retval);
        goto exit;
    }
 
    zend_fcc_dtor(&info->u.initializer.fcc);
    zval_ptr_dtor(&info->u.initializer.zv);
    info->u.instance = Z_OBJ(retval);
    info->flags |= ZEND_LAZY_OBJECT_INITIALIZED;
    OBJ_EXTRA_FLAGS(obj) |= IS_OBJ_LAZY_PROXY;
 
    /* unset() properties of the proxy. This ensures that all accesses are be
     * delegated to the backing instance from now on. */
    zend_object_dtor_dynamic_properties(obj);
    obj->properties = NULL;
 
    for (int i = 0; i < Z_OBJ(retval)->ce->default_properties_count; i++) {
        zend_property_info *prop_info = Z_OBJ(retval)->ce->properties_info_table[i];
        if (EXPECTED(prop_info)) {
            zval *prop = &obj->properties_table[OBJ_PROP_TO_NUM(prop_info->offset)];
            zend_object_dtor_property(obj, prop);
            ZVAL_UNDEF(prop);
            Z_PROP_FLAG_P(prop) = IS_PROP_UNINIT | IS_PROP_LAZY;
        }
    }
 
    instance = Z_OBJ(retval);
 
exit:
    if (UNEXPECTED(GC_DELREF(obj) == 0)) {
        zend_throw_error(NULL, "Lazy object was released during initialization");
        zend_objects_store_del(obj);
        instance = NULL;
    } else {
        gc_check_possible_root((zend_refcounted*) obj);
    }
 
    return instance;
}
 
/* Initialize a lazy object. */
ZEND_API zend_object *zend_lazy_object_init(zend_object *obj)
{
    ZEND_ASSERT(zend_object_is_lazy(obj));
 
    /* If obj is an initialized lazy proxy, return the real instance. This
     * supports the following pattern:
     * if (zend_lazy_object_must_init(obj)) {
     *     instance = zend_lazy_object_init(obj);
     * }
     */
    if (zend_lazy_object_initialized(obj)) {
        ZEND_ASSERT(zend_object_is_lazy_proxy(obj));
        zend_lazy_object_info *info = zend_lazy_object_get_info(obj);
        ZEND_ASSERT(info->flags & ZEND_LAZY_OBJECT_INITIALIZED);
        if (zend_object_is_lazy(info->u.instance)) {
            return zend_lazy_object_init(info->u.instance);
        }
        return info->u.instance;
    }
 
    zend_class_entry *ce = obj->ce;
 
    ZEND_ASSERT(ce->ce_flags & ZEND_ACC_CONSTANTS_UPDATED);
 
    if (zend_object_is_lazy_proxy(obj)) {
        return zend_lazy_object_init_proxy(obj);
    }
 
    /* Prevent object from being released during initialization */
    GC_ADDREF(obj);
 
    zend_fcall_info_cache *initializer = zend_lazy_object_get_initializer_fcc(obj);
 
    /* Prevent reentrant initialization */
    OBJ_EXTRA_FLAGS(obj) &= ~IS_OBJ_LAZY_UNINITIALIZED;
 
    /* Snapshot dynamic properties */
    HashTable *properties_snapshot = obj->properties;
    if (properties_snapshot) {
        GC_TRY_ADDREF(properties_snapshot);
    }
 
    zval *properties_table_snapshot = NULL;
 
    /* Snapshot declared properties and initialize lazy properties to their
     * default value */
    if (ce->default_properties_count) {
        zval *default_properties_table = CE_DEFAULT_PROPERTIES_TABLE(ce);
        zval *properties_table = obj->properties_table;
        properties_table_snapshot = emalloc(sizeof(*properties_table_snapshot) * ce->default_properties_count);
 
        for (int i = 0; i < ce->default_properties_count; i++) {
            ZVAL_COPY_PROP(&properties_table_snapshot[i], &properties_table[i]);
            if (Z_PROP_FLAG_P(&properties_table[i]) & IS_PROP_LAZY) {
                ZVAL_COPY_PROP(&properties_table[i], &default_properties_table[i]);
            }
        }
    }
 
    /* Call initializer */
    zval retval;
    int argc = 1;
    zval zobj;
    HashTable *named_params = NULL;
    zend_object *instance = NULL;
 
    ZVAL_OBJ(&zobj, obj);
 
    zend_call_known_fcc(initializer, &retval, argc, &zobj, named_params);
 
    if (EG(exception)) {
        zend_lazy_object_revert_init(obj, properties_table_snapshot, properties_snapshot);
        goto exit;
    }
 
    if (Z_TYPE(retval) != IS_NULL) {
        zend_lazy_object_revert_init(obj, properties_table_snapshot, properties_snapshot);
        zval_ptr_dtor(&retval);
        zend_type_error("Lazy object initializer must return NULL or no value");
        goto exit;
    }
 
    if (properties_table_snapshot) {
        for (int i = 0; i < obj->ce->default_properties_count; i++) {
            zval *p = &properties_table_snapshot[i];
            /* Use zval_ptr_dtor directly here (not zend_object_dtor_property),
             * as any reference type_source will have already been deleted in
             * case the prop is not bound to this value anymore. */
            i_zval_ptr_dtor(p);
        }
        efree(properties_table_snapshot);
    }
 
    if (properties_snapshot) {
        zend_release_properties(properties_snapshot);
    }
 
    /* Must be very last in this function, for the
     * zend_lazy_object_has_stale_info() check */
    zend_lazy_object_del_info(obj);
 
    instance = obj;
 
exit:
    if (UNEXPECTED(GC_DELREF(obj) == 0)) {
        zend_throw_error(NULL, "Lazy object was released during initialization");
        zend_objects_store_del(obj);
        instance = NULL;
    } else {
        gc_check_possible_root((zend_refcounted*) obj);
    }
 
    return instance;
}
 
/* Mark an object as non-lazy (after all properties were initialized) */
void zend_lazy_object_realize(zend_object *obj)
{
    ZEND_ASSERT(zend_object_is_lazy(obj));
    ZEND_ASSERT(!zend_lazy_object_initialized(obj));
 
    zend_lazy_object_del_info(obj);
 
#if ZEND_DEBUG
    for (int i = 0; i < obj->ce->default_properties_count; i++) {
        ZEND_ASSERT(!(Z_PROP_FLAG_P(&obj->properties_table[i]) & IS_PROP_LAZY));
    }
#endif
 
    OBJ_EXTRA_FLAGS(obj) &= ~(IS_OBJ_LAZY_UNINITIALIZED | IS_OBJ_LAZY_PROXY);
}
 
ZEND_API HashTable *zend_lazy_object_get_properties(zend_object *object)
{
    ZEND_ASSERT(zend_object_is_lazy(object));
 
    zend_object *tmp = zend_lazy_object_init(object);
    if (UNEXPECTED(!tmp)) {
        if (object->properties) {
            return object->properties;
        }
        return object->properties = zend_new_array(0);
    }
 
    object = tmp;
    ZEND_ASSERT(!zend_lazy_object_must_init(object));
 
    return zend_std_get_properties_ex(object);
}
 
/* Initialize object and clone it. For proxies, we clone both the proxy and its
 * real instance, and we don't call __clone() on the proxy. */
zend_object *zend_lazy_object_clone(zend_object *old_obj)
{
    ZEND_ASSERT(zend_object_is_lazy(old_obj));
 
    if (UNEXPECTED(!zend_lazy_object_initialized(old_obj) && !zend_lazy_object_init(old_obj))) {
        ZEND_ASSERT(EG(exception));
        /* Clone handler must always return an object. It is discarded later due
         * to the exception. */
        zval zv;
        object_init_ex(&zv, old_obj->ce);
        GC_ADD_FLAGS(Z_OBJ(zv), IS_OBJ_DESTRUCTOR_CALLED);
        return Z_OBJ(zv);
    }
 
    if (!zend_object_is_lazy_proxy(old_obj)) {
        return zend_objects_clone_obj(old_obj);
    }
 
    zend_lazy_object_info *info = zend_lazy_object_get_info(old_obj);
    zend_class_entry *ce = old_obj->ce;
    zend_object *new_proxy = zend_objects_new(ce);
 
    /* Iterate in reverse to avoid overriding Z_PROP_FLAG_P() of child props with added hooks (GH-17870). */
    for (int i = ce->default_properties_count - 1; i >= 0; i--) {
        zval *p = &new_proxy->properties_table[i];
        ZVAL_UNDEF(p);
        Z_PROP_FLAG_P(p) = 0;
 
        zend_property_info *prop_info = ce->properties_info_table[i];
        if (prop_info) {
            zval *p = &new_proxy->properties_table[OBJ_PROP_TO_NUM(prop_info->offset)];
            Z_PROP_FLAG_P(p) = IS_PROP_UNINIT | IS_PROP_LAZY;
        }
    }
 
    OBJ_EXTRA_FLAGS(new_proxy) = OBJ_EXTRA_FLAGS(old_obj);
 
    zend_lazy_object_info *new_info = emalloc(sizeof(*info));
    *new_info = *info;
    new_info->u.instance = zend_objects_clone_obj(info->u.instance);
 
    zend_lazy_object_set_info(new_proxy, new_info);
 
    return new_proxy;
}
 
HashTable *zend_lazy_object_debug_info(zend_object *object, int *is_temp)
{
    ZEND_ASSERT(zend_object_is_lazy(object));
 
    if (zend_object_is_lazy_proxy(object)) {
        if (zend_lazy_object_initialized(object)) {
            HashTable *properties = zend_new_array(0);
            zval instance;
            ZVAL_OBJ(&instance, zend_lazy_object_get_instance(object));
            Z_ADDREF(instance);
            zend_hash_str_add(properties, "instance", strlen("instance"), &instance);
            *is_temp = 1;
            return properties;
        }
    }
 
    *is_temp = 0;
    return zend_get_properties_no_lazy_init(object);
}
 
HashTable *zend_lazy_object_get_gc(zend_object *zobj, zval **table, int *n)
{
    ZEND_ASSERT(zend_object_is_lazy(zobj));
 
    zend_lazy_object_info *info = zend_lazy_object_get_info(zobj);
    zend_get_gc_buffer *gc_buffer = zend_get_gc_buffer_create();
 
    if (zend_lazy_object_initialized(zobj)) {
        ZEND_ASSERT(zend_object_is_lazy_proxy(zobj));
        zend_get_gc_buffer_add_obj(gc_buffer, info->u.instance);
        zend_get_gc_buffer_use(gc_buffer, table, n);
        /* Initialized proxy object can not have properties */
        return NULL;
    }
 
    zend_fcall_info_cache *fcc = &info->u.initializer.fcc;
    if (fcc->object) {
        zend_get_gc_buffer_add_obj(gc_buffer, fcc->object);
    }
    if (fcc->closure) {
        zend_get_gc_buffer_add_obj(gc_buffer, fcc->closure);
    }
    zend_get_gc_buffer_add_zval(gc_buffer, &info->u.initializer.zv);
 
    /* Uninitialized lazy objects can not have dynamic properties, so we can
     * ignore zobj->properties. */
    zval *prop = zobj->properties_table;
    zval *end = prop + zobj->ce->default_properties_count;
    for ( ; prop < end; prop++) {
        zend_get_gc_buffer_add_zval(gc_buffer, prop);
    }
 
    zend_get_gc_buffer_use(gc_buffer, table, n);
    return NULL;
}
 
zend_property_info *zend_lazy_object_get_property_info_for_slot(zend_object *obj, zval *slot)
{
    ZEND_ASSERT(zend_object_is_lazy_proxy(obj));
 
    zend_property_info **table = obj->ce->properties_info_table;
    intptr_t prop_num = slot - obj->properties_table;
    if (prop_num >= 0 && prop_num < obj->ce->default_properties_count) {
        if (table[prop_num]) {
            return table[prop_num];
        } else {
            return zend_get_property_info_for_slot_slow(obj, slot);
        }
    }
 
    if (!zend_lazy_object_initialized(obj)) {
        return NULL;
    }
 
    obj = zend_lazy_object_get_instance(obj);
    return zend_get_property_info_for_slot(obj, slot);
}