php-src/Zend/zend_property_hooks.c

/*
   +----------------------------------------------------------------------+
   | 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: Ilija Tovilo <ilutov@php.net>                               |
   +----------------------------------------------------------------------+
*/

#include "zend.h"
#include "zend_API.h"
#include "zend_hash.h"
#include "zend_lazy_objects.h"
#include "zend_property_hooks.h"

typedef struct {
	zend_object_iterator it;
	bool by_ref;
	bool declared_props_done;
	zval declared_props;
	bool dynamic_props_done;
	uint32_t dynamic_prop_it;
	zval current_key;
	zval current_data;
} zend_hooked_object_iterator;

static zend_result zho_it_valid(zend_object_iterator *iter);
static void zho_it_move_forward(zend_object_iterator *iter);

// FIXME: This should probably be stored on zend_class_entry somewhere (e.g. through num_virtual_props).
static uint32_t zho_num_backed_props(zend_object *zobj)
{
	zend_property_info *prop_info;
	int backed_property_count = 0;
	ZEND_HASH_MAP_FOREACH_PTR(&zobj->ce->properties_info, prop_info) {
		if (!(prop_info->flags & (ZEND_ACC_STATIC|ZEND_ACC_VIRTUAL))) {
			backed_property_count++;
		}
	} ZEND_HASH_FOREACH_END();
	return backed_property_count;
}

static zend_array *zho_build_properties_ex(zend_object *zobj, bool check_access, bool include_dynamic_props)
{
	if (UNEXPECTED(zend_lazy_object_must_init(zobj))) {
		zobj = zend_lazy_object_init(zobj);
		if (UNEXPECTED(!zobj)) {
			return zend_new_array(0);
		}
	}

	zend_class_entry *ce = zobj->ce;
	zend_array *properties = zend_new_array(ce->default_properties_count);
	zend_hash_real_init_mixed(properties);

	zend_property_info *prop_info;
	ZEND_HASH_MAP_FOREACH_PTR(&ce->properties_info, prop_info) {
		if (prop_info->flags & ZEND_ACC_STATIC) {
			continue;
		}
		if (check_access && zend_check_property_access(zobj, prop_info->name, false) == FAILURE) {
			continue;
		}
		if (prop_info->hooks) {
			_zend_hash_append_ptr(properties, prop_info->name, prop_info);
		} else {
			if (UNEXPECTED(Z_TYPE_P(OBJ_PROP(zobj, prop_info->offset)) == IS_UNDEF)) {
				HT_FLAGS(properties) |= HASH_FLAG_HAS_EMPTY_IND;
			}
			_zend_hash_append_ind(properties, prop_info->name, OBJ_PROP(zobj, prop_info->offset));
		}
	} ZEND_HASH_FOREACH_END();

	if (include_dynamic_props && zobj->properties) {
		zend_string *prop_name;
		zval *prop_value;
		ZEND_HASH_FOREACH_STR_KEY_VAL_FROM(zobj->properties, prop_name, prop_value, zho_num_backed_props(zobj)) {
			Z_TRY_ADDREF_P(_zend_hash_append(properties, prop_name, prop_value));
		} ZEND_HASH_FOREACH_END();
	}

	return properties;
}

ZEND_API zend_array *zend_hooked_object_build_properties(zend_object *zobj)
{
	return zho_build_properties_ex(zobj, false, true);
}

static bool zho_dynamic_it_init(zend_hooked_object_iterator *hooked_iter)
{
	if (hooked_iter->dynamic_prop_it != (uint32_t) -1) {
		return true;
	}

	zend_object *zobj = Z_OBJ_P(&hooked_iter->it.data);
	if (!zobj->properties || zho_num_backed_props(zobj) == zobj->properties->nNumUsed) {
		hooked_iter->dynamic_props_done = true;
		return false;
	}

	hooked_iter->dynamic_prop_it = zend_hash_iterator_add(zobj->properties, zho_num_backed_props(zobj));
	return true;
}

static void zho_it_get_current_key(zend_object_iterator *iter, zval *key);

static void zho_declared_it_fetch_current(zend_object_iterator *iter)
{
	zend_hooked_object_iterator *hooked_iter = (zend_hooked_object_iterator*)iter;
	zend_object *zobj = Z_OBJ_P(&iter->data);
	zend_array *properties = Z_ARR(hooked_iter->declared_props);

	zval *property = zend_hash_get_current_data(properties);
	if (Z_TYPE_P(property) == IS_PTR) {
		zend_property_info *prop_info = Z_PTR_P(property);
		zend_function *get = prop_info->hooks[ZEND_PROPERTY_HOOK_GET];
		if (!get && (prop_info->flags & ZEND_ACC_VIRTUAL)) {
			return;
		}
		if (hooked_iter->by_ref
		 && (get == NULL
		  || !(get->common.fn_flags & ZEND_ACC_RETURN_REFERENCE))) {
			zend_throw_error(NULL, "Cannot create reference to property %s::$%s",
				ZSTR_VAL(zobj->ce->name), zend_get_unmangled_property_name(prop_info->name));
			return;
		}
		zval *value = zend_read_property_ex(prop_info->ce, zobj, prop_info->name, /* silent */ true, &hooked_iter->current_data);
		if (value == &EG(uninitialized_zval)) {
			return;
		} else if (value != &hooked_iter->current_data) {
			ZVAL_COPY(&hooked_iter->current_data, value);
		}
	} else {
		ZVAL_DEINDIRECT(property);
		if (Z_TYPE_P(property) == IS_UNDEF) {
			return;
		}
		if (!hooked_iter->by_ref) {
			ZVAL_DEREF(property);
		} else if (Z_TYPE_P(property) != IS_REFERENCE) {
			ZVAL_MAKE_REF(property);

			zend_property_info *prop_info = zend_get_property_info_for_slot(zobj, property);
			if (ZEND_TYPE_IS_SET(prop_info->type)) {
				ZEND_REF_ADD_TYPE_SOURCE(Z_REF_P(property), prop_info);
			}
		}
		ZVAL_COPY(&hooked_iter->current_data, property);
	}
	zend_hash_get_current_key_zval(properties, &hooked_iter->current_key);
}

static void zho_dynamic_it_fetch_current(zend_object_iterator *iter)
{
	zend_hooked_object_iterator *hooked_iter = (zend_hooked_object_iterator*)iter;
	ZEND_ASSERT(hooked_iter->dynamic_prop_it != (uint32_t) -1);

	zend_array *properties = Z_OBJ(iter->data)->properties;
	HashPosition pos = zend_hash_iterator_pos(hooked_iter->dynamic_prop_it, properties);

	Bucket *bucket = properties->arData + pos;
	if (hooked_iter->by_ref && Z_TYPE(bucket->val) != IS_REFERENCE) {
		ZEND_ASSERT(Z_TYPE(bucket->val) != IS_UNDEF);
		ZVAL_MAKE_REF(&bucket->val);
	}
	ZVAL_COPY(&hooked_iter->current_data, &bucket->val);

	if (bucket->key) {
		ZVAL_STR_COPY(&hooked_iter->current_key, bucket->key);
	} else {
		ZVAL_LONG(&hooked_iter->current_key, bucket->h);
	}
}

static void zho_it_fetch_current(zend_object_iterator *iter)
{
	zend_hooked_object_iterator *hooked_iter = (zend_hooked_object_iterator*)iter;
	if (Z_TYPE(hooked_iter->current_data) != IS_UNDEF) {
		return;
	}

	while (true) {
		if (!hooked_iter->declared_props_done) {
			zho_declared_it_fetch_current(iter);
		} else if (!hooked_iter->dynamic_props_done && zho_dynamic_it_init(hooked_iter)) {
			zho_dynamic_it_fetch_current(iter);
		} else {
			break;
		}
		if (Z_TYPE(hooked_iter->current_data) != IS_UNDEF || EG(exception)) {
			break;
		}
		zho_it_move_forward(iter);
	}
}

static void zho_it_dtor(zend_object_iterator *iter)
{
	zend_hooked_object_iterator *hooked_iter = (zend_hooked_object_iterator*)iter;
	zval_ptr_dtor(&iter->data);
	zval_ptr_dtor(&hooked_iter->declared_props);
	zval_ptr_dtor_nogc(&hooked_iter->current_key);
	zval_ptr_dtor(&hooked_iter->current_data);
	if (hooked_iter->dynamic_prop_it != (uint32_t) -1) {
		zend_hash_iterator_del(hooked_iter->dynamic_prop_it);
	}
}

static zend_result zho_it_valid(zend_object_iterator *iter)
{
	zend_hooked_object_iterator *hooked_iter = (zend_hooked_object_iterator*)iter;
	zho_it_fetch_current(iter);
	return Z_TYPE(hooked_iter->current_data) != IS_UNDEF ? SUCCESS : FAILURE;
}

static zval *zho_it_get_current_data(zend_object_iterator *iter)
{
	zend_hooked_object_iterator *hooked_iter = (zend_hooked_object_iterator*)iter;
	zho_it_fetch_current(iter);
	return &hooked_iter->current_data;
}

static void zho_it_get_current_key(zend_object_iterator *iter, zval *key)
{
	zend_hooked_object_iterator *hooked_iter = (zend_hooked_object_iterator*)iter;
	zho_it_fetch_current(iter);
	ZVAL_COPY(key, &hooked_iter->current_key);
}

static void zho_it_move_forward(zend_object_iterator *iter)
{
	zend_hooked_object_iterator *hooked_iter = (zend_hooked_object_iterator*)iter;

	zval_ptr_dtor(&hooked_iter->current_data);
	ZVAL_UNDEF(&hooked_iter->current_data);
	zval_ptr_dtor_nogc(&hooked_iter->current_key);
	ZVAL_UNDEF(&hooked_iter->current_key);

	if (!hooked_iter->declared_props_done) {
		zend_array *properties = Z_ARR(hooked_iter->declared_props);
		zend_hash_move_forward(properties);
		if (zend_hash_has_more_elements(properties) != SUCCESS) {
			hooked_iter->declared_props_done = true;
		}
	} else if (!hooked_iter->dynamic_props_done && zho_dynamic_it_init(hooked_iter)) {
		zend_array *properties = Z_OBJ(iter->data)->properties;
		HashPosition pos = zend_hash_iterator_pos(hooked_iter->dynamic_prop_it, properties);
		pos++;
		EG(ht_iterators)[hooked_iter->dynamic_prop_it].pos = pos;
		if (pos >= properties->nNumUsed) {
			hooked_iter->dynamic_props_done = true;
		}
	}
}

static void zho_it_rewind(zend_object_iterator *iter)
{
	zend_hooked_object_iterator *hooked_iter = (zend_hooked_object_iterator*)iter;

	zval_ptr_dtor(&hooked_iter->current_data);
	ZVAL_UNDEF(&hooked_iter->current_data);
	zval_ptr_dtor_nogc(&hooked_iter->current_key);
	ZVAL_UNDEF(&hooked_iter->current_key);

	hooked_iter->declared_props_done = false;
	zend_array *properties = Z_ARR(hooked_iter->declared_props);
	zend_hash_internal_pointer_reset(properties);
	hooked_iter->dynamic_props_done = false;
	if (hooked_iter->dynamic_prop_it != (uint32_t) -1) {
		EG(ht_iterators)[hooked_iter->dynamic_prop_it].pos = zho_num_backed_props(Z_OBJ(iter->data));
	}
}

static HashTable *zho_it_get_gc(zend_object_iterator *iter, zval **table, int *n)
{
	zend_hooked_object_iterator *hooked_iter = (zend_hooked_object_iterator*)iter;
	zend_get_gc_buffer *gc_buffer = zend_get_gc_buffer_create();
	zend_get_gc_buffer_add_zval(gc_buffer, &iter->data);
	zend_get_gc_buffer_add_zval(gc_buffer, &hooked_iter->declared_props);
	zend_get_gc_buffer_add_zval(gc_buffer, &hooked_iter->current_data);
	zend_get_gc_buffer_use(gc_buffer, table, n);
	return NULL;
}

static const zend_object_iterator_funcs zend_hooked_object_it_funcs = {
	zho_it_dtor,
	zho_it_valid,
	zho_it_get_current_data,
	zho_it_get_current_key,
	zho_it_move_forward,
	zho_it_rewind,
	NULL,
	zho_it_get_gc,
};

ZEND_API zend_object_iterator *zend_hooked_object_get_iterator(zend_class_entry *ce, zval *object, int by_ref)
{
	zend_hooked_object_iterator *iterator = emalloc(sizeof(zend_hooked_object_iterator));
	zend_iterator_init(&iterator->it);

	ZVAL_OBJ_COPY(&iterator->it.data, Z_OBJ_P(object));
	iterator->it.funcs = &zend_hooked_object_it_funcs;
	iterator->by_ref = by_ref;
	iterator->declared_props_done = false;
	zend_array *properties = zho_build_properties_ex(Z_OBJ_P(object), true, false);
	ZVAL_ARR(&iterator->declared_props, properties);
	iterator->dynamic_props_done = false;
	iterator->dynamic_prop_it = (uint32_t) -1;
	ZVAL_UNDEF(&iterator->current_key);
	ZVAL_UNDEF(&iterator->current_data);

	return &iterator->it;
}