/src/php-src/Zend/zend_interfaces.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: Marcus Boerger <helly@php.net>                              |
   +----------------------------------------------------------------------+
*/

#include "zend.h"
#include "zend_API.h"
#include "zend_interfaces.h"
#include "zend_exceptions.h"
#include "zend_interfaces_arginfo.h"

ZEND_API zend_class_entry *zend_ce_traversable;
ZEND_API zend_class_entry *zend_ce_aggregate;
ZEND_API zend_class_entry *zend_ce_iterator;
ZEND_API zend_class_entry *zend_ce_arrayaccess;
ZEND_API zend_class_entry *zend_ce_serializable;
ZEND_API zend_class_entry *zend_ce_countable;
ZEND_API zend_class_entry *zend_ce_stringable;
ZEND_API zend_class_entry *zend_ce_internal_iterator;

static zend_object_handlers zend_internal_iterator_handlers;

/* {{{ zend_call_method
 Only returns the returned zval if retval_ptr != NULL */
ZEND_API zval* zend_call_method(zend_object *object, zend_class_entry *obj_ce, zend_function **fn_proxy, const char *function_name, size_t function_name_len, zval *retval_ptr, uint32_t param_count, zval* arg1, zval* arg2)
{
  zend_function *fn;
  zend_class_entry *called_scope;
  zval params[2];

  if (param_count > 0) {
    ZVAL_COPY_VALUE(&params[0], arg1);
  }
  if (param_count > 1) {
    ZVAL_COPY_VALUE(&params[1], arg2);
  }

  if (!obj_ce) {
    obj_ce = object ? object->ce : NULL;
  }
  if (!fn_proxy || !*fn_proxy) {
    if (EXPECTED(obj_ce)) {
      fn = zend_hash_str_find_ptr_lc(
        &obj_ce->function_table, function_name, function_name_len);
      if (UNEXPECTED(fn == NULL)) {
        /* error at c-level */
        zend_error_noreturn(E_CORE_ERROR, "Couldn't find implementation for method %s::%s", ZSTR_VAL(obj_ce->name), function_name);
      }
    } else {
      fn = zend_fetch_function_str(function_name, function_name_len);
      if (UNEXPECTED(fn == NULL)) {
        /* error at c-level */
        zend_error_noreturn(E_CORE_ERROR, "Couldn't find implementation for function %s", function_name);
      }
    }
    if (fn_proxy) {
      *fn_proxy = fn;
    }
  } else {
    fn = *fn_proxy;
  }

  if (object) {
    called_scope = object->ce;
  } else {
    called_scope = obj_ce;
  }

  zend_call_known_function(fn, object, called_scope, retval_ptr, param_count, params, NULL);
  return retval_ptr;
}
/* }}} */

/* iterator interface, c-level functions used by engine */

/* {{{ zend_user_it_new_iterator */
ZEND_API void zend_user_it_new_iterator(zend_class_entry *ce, zval *object, zval *retval)
{
  zend_call_known_instance_method_with_0_params(
    ce->iterator_funcs_ptr->zf_new_iterator, Z_OBJ_P(object), retval);
}
/* }}} */

/* {{{ zend_user_it_invalidate_current */
ZEND_API void zend_user_it_invalidate_current(zend_object_iterator *_iter)
{
  zend_user_iterator *iter = (zend_user_iterator*)_iter;

  if (!Z_ISUNDEF(iter->value)) {
    zval_ptr_dtor(&iter->value);
    ZVAL_UNDEF(&iter->value);
  }
}
/* }}} */

/* {{{ zend_user_it_dtor */
static void zend_user_it_dtor(zend_object_iterator *_iter)
{
  zend_user_iterator *iter = (zend_user_iterator*)_iter;
  zval *object = &iter->it.data;

  zend_user_it_invalidate_current(_iter);
  zval_ptr_dtor(object);
}
/* }}} */

/* {{{ zend_user_it_valid */
ZEND_API int zend_user_it_valid(zend_object_iterator *_iter)
{
  if (_iter) {
    zend_user_iterator *iter = (zend_user_iterator*)_iter;
    zval *object = &iter->it.data;
    zval more;
    bool result;

    zend_call_method_with_0_params(Z_OBJ_P(object), iter->ce, &iter->ce->iterator_funcs_ptr->zf_valid, "valid", &more);
    result = i_zend_is_true(&more);
    zval_ptr_dtor(&more);
    return result ? SUCCESS : FAILURE;
  }
  return FAILURE;
}
/* }}} */

/* {{{ zend_user_it_get_current_data */
ZEND_API zval *zend_user_it_get_current_data(zend_object_iterator *_iter)
{
  zend_user_iterator *iter = (zend_user_iterator*)_iter;
  zval *object = &iter->it.data;

  if (Z_ISUNDEF(iter->value)) {
    zend_call_method_with_0_params(Z_OBJ_P(object), iter->ce, &iter->ce->iterator_funcs_ptr->zf_current, "current", &iter->value);
  }
  return &iter->value;
}
/* }}} */

/* {{{ zend_user_it_get_current_key */
ZEND_API void zend_user_it_get_current_key(zend_object_iterator *_iter, zval *key)
{
  zend_user_iterator *iter = (zend_user_iterator*)_iter;
  zval *object = &iter->it.data;
  zval retval;

  zend_call_method_with_0_params(Z_OBJ_P(object), iter->ce, &iter->ce->iterator_funcs_ptr->zf_key, "key", &retval);

  if (Z_TYPE(retval) != IS_UNDEF) {
    ZVAL_COPY_VALUE(key, &retval);
  } else {
    if (!EG(exception)) {
      zend_error(E_WARNING, "Nothing returned from %s::key()", ZSTR_VAL(iter->ce->name));
    }

    ZVAL_LONG(key, 0);
  }
}
/* }}} */

/* {{{ zend_user_it_move_forward */
ZEND_API void zend_user_it_move_forward(zend_object_iterator *_iter)
{
  zend_user_iterator *iter = (zend_user_iterator*)_iter;
  zval *object = &iter->it.data;

  zend_user_it_invalidate_current(_iter);
  zend_call_method_with_0_params(Z_OBJ_P(object), iter->ce, &iter->ce->iterator_funcs_ptr->zf_next, "next", NULL);
}
/* }}} */

/* {{{ zend_user_it_rewind */
ZEND_API void zend_user_it_rewind(zend_object_iterator *_iter)
{
  zend_user_iterator *iter = (zend_user_iterator*)_iter;
  zval *object = &iter->it.data;

  zend_user_it_invalidate_current(_iter);
  zend_call_method_with_0_params(Z_OBJ_P(object), iter->ce, &iter->ce->iterator_funcs_ptr->zf_rewind, "rewind", NULL);
}
/* }}} */

static const zend_object_iterator_funcs zend_interface_iterator_funcs_iterator = {
  zend_user_it_dtor,
  zend_user_it_valid,
  zend_user_it_get_current_data,
  zend_user_it_get_current_key,
  zend_user_it_move_forward,
  zend_user_it_rewind,
  zend_user_it_invalidate_current,
  NULL, /* get_gc */
};

/* {{{ zend_user_it_get_iterator */
/* by_ref is int due to Iterator API */
static zend_object_iterator *zend_user_it_get_iterator(zend_class_entry *ce, zval *object, int by_ref)
{
  zend_user_iterator *iterator;

  if (by_ref) {
    zend_throw_error(NULL, "An iterator cannot be used with foreach by reference");
    return NULL;
  }

  iterator = emalloc(sizeof(zend_user_iterator));

  zend_iterator_init((zend_object_iterator*)iterator);

  ZVAL_OBJ_COPY(&iterator->it.data, Z_OBJ_P(object));
  iterator->it.funcs = &zend_interface_iterator_funcs_iterator;
  iterator->ce = Z_OBJCE_P(object);
  ZVAL_UNDEF(&iterator->value);
  return (zend_object_iterator*)iterator;
}
/* }}} */

/* {{{ zend_user_it_get_new_iterator */
/* by_ref is int due to Iterator API */
ZEND_API zend_object_iterator *zend_user_it_get_new_iterator(zend_class_entry *ce, zval *object, int by_ref)
{
  zval iterator;
  zend_object_iterator *new_iterator;
  zend_class_entry *ce_it;

  zend_user_it_new_iterator(ce, object, &iterator);
  ce_it = (Z_TYPE(iterator) == IS_OBJECT) ? Z_OBJCE(iterator) : NULL;

  if (!ce_it || !ce_it->get_iterator || (ce_it->get_iterator == zend_user_it_get_new_iterator && Z_OBJ(iterator) == Z_OBJ_P(object))) {
    if (!EG(exception)) {
      zend_throw_exception_ex(NULL, 0, "Objects returned by %s::getIterator() must be traversable or implement interface Iterator", ce ? ZSTR_VAL(ce->name) : ZSTR_VAL(Z_OBJCE_P(object)->name));
    }
    zval_ptr_dtor(&iterator);
    return NULL;
  }

  new_iterator = ce_it->get_iterator(ce_it, &iterator, by_ref);
  zval_ptr_dtor(&iterator);
  return new_iterator;
}
/* }}} */

/* {{{ zend_implement_traversable */
static int zend_implement_traversable(zend_class_entry *interface, zend_class_entry *class_type)
{
  /* Abstract class can implement Traversable only, in which case the extending class must
   * implement Iterator or IteratorAggregate. */
  if (class_type->ce_flags & ZEND_ACC_EXPLICIT_ABSTRACT_CLASS) {
    return SUCCESS;
  }

  /* Check that class_type implements at least one of 'IteratorAggregate' or 'Iterator' */
  if (class_type->num_interfaces) {
    ZEND_ASSERT(class_type->ce_flags & ZEND_ACC_RESOLVED_INTERFACES);
    for (uint32_t i = 0; i < class_type->num_interfaces; i++) {
      if (class_type->interfaces[i] == zend_ce_aggregate || class_type->interfaces[i] == zend_ce_iterator) {
        return SUCCESS;
      }
    }
  }
  zend_error_noreturn(E_CORE_ERROR, "Class %s must implement interface %s as part of either %s or %s",
    ZSTR_VAL(class_type->name),
    ZSTR_VAL(zend_ce_traversable->name),
    ZSTR_VAL(zend_ce_iterator->name),
    ZSTR_VAL(zend_ce_aggregate->name));
  return FAILURE;
}
/* }}} */

/* {{{ zend_implement_aggregate */
static int zend_implement_aggregate(zend_class_entry *interface, zend_class_entry *class_type)
{
  if (zend_class_implements_interface(class_type, zend_ce_iterator)) {
    zend_error_noreturn(E_ERROR,
      "Class %s cannot implement both Iterator and IteratorAggregate at the same time",
      ZSTR_VAL(class_type->name));
  }

  zend_function *zf = zend_hash_str_find_ptr(
    &class_type->function_table, "getiterator", sizeof("getiterator") - 1);
  if (class_type->get_iterator && class_type->get_iterator != zend_user_it_get_new_iterator) {
    /* get_iterator was explicitly assigned for an internal class. */
    if (!class_type->parent || class_type->parent->get_iterator != class_type->get_iterator) {
      ZEND_ASSERT(class_type->type == ZEND_INTERNAL_CLASS);
      return SUCCESS;
    }

    /* The getIterator() method has not been overwritten, use inherited get_iterator(). */
    if (zf->common.scope != class_type) {
      return SUCCESS;
    }

    /* getIterator() has been overwritten, switch to zend_user_it_get_new_iterator. */
  }

  ZEND_ASSERT(!class_type->iterator_funcs_ptr && "Iterator funcs already set?");
  zend_class_iterator_funcs *funcs_ptr = class_type->type == ZEND_INTERNAL_CLASS
    ? pemalloc(sizeof(zend_class_iterator_funcs), 1)
    : zend_arena_alloc(&CG(arena), sizeof(zend_class_iterator_funcs));
  class_type->get_iterator = zend_user_it_get_new_iterator;
  class_type->iterator_funcs_ptr = funcs_ptr;

  memset(funcs_ptr, 0, sizeof(zend_class_iterator_funcs));
  funcs_ptr->zf_new_iterator = zf;

  return SUCCESS;
}
/* }}} */

/* {{{ zend_implement_iterator */
static int zend_implement_iterator(zend_class_entry *interface, zend_class_entry *class_type)
{
  if (zend_class_implements_interface(class_type, zend_ce_aggregate)) {
    zend_error_noreturn(E_ERROR,
      "Class %s cannot implement both Iterator and IteratorAggregate at the same time",
      ZSTR_VAL(class_type->name));
  }

  if (class_type->get_iterator && class_type->get_iterator != zend_user_it_get_iterator) {
    if (!class_type->parent || class_type->parent->get_iterator != class_type->get_iterator) {
      /* get_iterator was explicitly assigned for an internal class. */
      ZEND_ASSERT(class_type->type == ZEND_INTERNAL_CLASS);
      return SUCCESS;
    }
    /* Otherwise get_iterator was inherited from the parent by default. */
  }

  if (class_type->parent && (class_type->parent->ce_flags & ZEND_ACC_REUSE_GET_ITERATOR)) {
    /* Keep the inherited get_iterator handler. */
    class_type->ce_flags |= ZEND_ACC_REUSE_GET_ITERATOR;
  } else {
    class_type->get_iterator = zend_user_it_get_iterator;
  }

  ZEND_ASSERT(!class_type->iterator_funcs_ptr && "Iterator funcs already set?");
  zend_class_iterator_funcs *funcs_ptr = class_type->type == ZEND_INTERNAL_CLASS
    ? pemalloc(sizeof(zend_class_iterator_funcs), 1)
    : zend_arena_alloc(&CG(arena), sizeof(zend_class_iterator_funcs));
  memset(funcs_ptr, 0, sizeof(zend_class_iterator_funcs));
  class_type->iterator_funcs_ptr = funcs_ptr;

  return SUCCESS;
}
/* }}} */

/* {{{ zend_user_serialize */
ZEND_API int zend_user_serialize(zval *object, unsigned char **buffer, size_t *buf_len, zend_serialize_data *data)
{
  zend_class_entry * ce = Z_OBJCE_P(object);
  zval retval;
  zend_result result;

  zend_call_method_with_0_params(
    Z_OBJ_P(object), Z_OBJCE_P(object), NULL, "serialize", &retval);

  if (Z_TYPE(retval) == IS_UNDEF || EG(exception)) {
    result = FAILURE;
  } else {
    switch(Z_TYPE(retval)) {
    case IS_NULL:
      /* we could also make this '*buf_len = 0' but this allows to skip variables */
      zval_ptr_dtor(&retval);
      return FAILURE;
    case IS_STRING:
      *buffer = (unsigned char*)estrndup(Z_STRVAL(retval), Z_STRLEN(retval));
      *buf_len = Z_STRLEN(retval);
      result = SUCCESS;
      break;
    default: /* failure */
      result = FAILURE;
      break;
    }
    zval_ptr_dtor(&retval);
  }

  if (result == FAILURE && !EG(exception)) {
    zend_throw_exception_ex(NULL, 0, "%s::serialize() must return a string or NULL", ZSTR_VAL(ce->name));
  }
  return result;
}
/* }}} */

/* {{{ zend_user_unserialize */
ZEND_API int zend_user_unserialize(zval *object, zend_class_entry *ce, const unsigned char *buf, size_t buf_len, zend_unserialize_data *data)
{
  zval zdata;

  if (UNEXPECTED(object_init_ex(object, ce) != SUCCESS)) {
    return FAILURE;
  }

  ZVAL_STRINGL(&zdata, (char*)buf, buf_len);
  zend_call_method_with_1_params(
    Z_OBJ_P(object), Z_OBJCE_P(object), NULL, "unserialize", NULL, &zdata);
  zval_ptr_dtor(&zdata);

  if (EG(exception)) {
    return FAILURE;
  } else {
    return SUCCESS;
  }
}
/* }}} */

ZEND_API int zend_class_serialize_deny(zval *object, unsigned char **buffer, size_t *buf_len, zend_serialize_data *data) /* {{{ */
{
  zend_class_entry *ce = Z_OBJCE_P(object);
  zend_throw_exception_ex(NULL, 0, "Serialization of '%s' is not allowed", ZSTR_VAL(ce->name));
  return FAILURE;
}
/* }}} */

ZEND_API int zend_class_unserialize_deny(zval *object, zend_class_entry *ce, const unsigned char *buf, size_t buf_len, zend_unserialize_data *data) /* {{{ */
{
  zend_throw_exception_ex(NULL, 0, "Unserialization of '%s' is not allowed", ZSTR_VAL(ce->name));
  return FAILURE;
}
/* }}} */

/* {{{ zend_implement_serializable */
static int zend_implement_serializable(zend_class_entry *interface, zend_class_entry *class_type)
{
  if (class_type->parent
    && (class_type->parent->serialize || class_type->parent->unserialize)
    && !zend_class_implements_interface(class_type->parent, zend_ce_serializable)) {
    return FAILURE;
  }
  if (!class_type->serialize) {
    class_type->serialize = zend_user_serialize;
  }
  if (!class_type->unserialize) {
    class_type->unserialize = zend_user_unserialize;
  }
  return SUCCESS;
}
/* }}}*/

typedef struct {
  zend_object std;
  zend_object_iterator *iter;
  zend_bool rewind_called;
} zend_internal_iterator;

static zend_object *zend_internal_iterator_create(zend_class_entry *ce) {
  zend_internal_iterator *intern = emalloc(sizeof(zend_internal_iterator));
  zend_object_std_init(&intern->std, ce);
  intern->std.handlers = &zend_internal_iterator_handlers;
  intern->iter = NULL;
  intern->rewind_called = 0;
  return &intern->std;
}

ZEND_API zend_result zend_create_internal_iterator_zval(zval *return_value, zval *obj) {
  zend_class_entry *scope = EG(current_execute_data)->func->common.scope;
  ZEND_ASSERT(scope->get_iterator != zend_user_it_get_new_iterator);
  zend_object_iterator *iter = scope->get_iterator(Z_OBJCE_P(obj), obj, /* by_ref */ 0);
  if (!iter) {
    return FAILURE;
  }

  zend_internal_iterator *intern =
    (zend_internal_iterator *) zend_internal_iterator_create(zend_ce_internal_iterator);
  intern->iter = iter;
  intern->iter->index = 0;
  ZVAL_OBJ(return_value, &intern->std);
  return SUCCESS;
}

static void zend_internal_iterator_free(zend_object *obj) {
  zend_internal_iterator *intern = (zend_internal_iterator *) obj;
  if (intern->iter) {
    zend_iterator_dtor(intern->iter);
  }
  zend_object_std_dtor(&intern->std);
}

static zend_internal_iterator *zend_internal_iterator_fetch(zval *This) {
  zend_internal_iterator *intern = (zend_internal_iterator *) Z_OBJ_P(This);
  if (!intern->iter) {
    zend_throw_error(NULL, "The InternalIterator object has not been properly initialized");
    return NULL;
  }
  return intern;
}

/* Many iterators will not behave correctly if rewind() is not called, make sure it happens. */
static zend_result zend_internal_iterator_ensure_rewound(zend_internal_iterator *intern) {
  if (!intern->rewind_called) {
    zend_object_iterator *iter = intern->iter;
    intern->rewind_called = 1;
    if (iter->funcs->rewind) {
      iter->funcs->rewind(iter);
      if (UNEXPECTED(EG(exception))) {
        return FAILURE;
      }
    }
  }
  return SUCCESS;
}


ZEND_METHOD(InternalIterator, __construct) {
  zend_throw_error(NULL, "Cannot manually construct InternalIterator");
}

ZEND_METHOD(InternalIterator, current) {
  ZEND_PARSE_PARAMETERS_NONE();

  zend_internal_iterator *intern = zend_internal_iterator_fetch(ZEND_THIS);
  if (!intern) {
    RETURN_THROWS();
  }

  if (zend_internal_iterator_ensure_rewound(intern) == FAILURE) {
    RETURN_THROWS();
  }

  zval *data = intern->iter->funcs->get_current_data(intern->iter);
  if (data) {
    ZVAL_COPY_DEREF(return_value, data);
  }
}

ZEND_METHOD(InternalIterator, key) {
  ZEND_PARSE_PARAMETERS_NONE();

  zend_internal_iterator *intern = zend_internal_iterator_fetch(ZEND_THIS);
  if (!intern) {
    RETURN_THROWS();
  }

  if (zend_internal_iterator_ensure_rewound(intern) == FAILURE) {
    RETURN_THROWS();
  }

  if (intern->iter->funcs->get_current_key) {
    intern->iter->funcs->get_current_key(intern->iter, return_value);
  } else {
    RETURN_LONG(intern->iter->index);
  }
}

ZEND_METHOD(InternalIterator, next) {
  ZEND_PARSE_PARAMETERS_NONE();

  zend_internal_iterator *intern = zend_internal_iterator_fetch(ZEND_THIS);
  if (!intern) {
    RETURN_THROWS();
  }

  if (zend_internal_iterator_ensure_rewound(intern) == FAILURE) {
    RETURN_THROWS();
  }

  /* Advance index first to match foreach behavior. */
  intern->iter->index++;
  intern->iter->funcs->move_forward(intern->iter);
}

ZEND_METHOD(InternalIterator, valid) {
  ZEND_PARSE_PARAMETERS_NONE();

  zend_internal_iterator *intern = zend_internal_iterator_fetch(ZEND_THIS);
  if (!intern) {
    RETURN_THROWS();
  }

  if (zend_internal_iterator_ensure_rewound(intern) == FAILURE) {
    RETURN_THROWS();
  }

  RETURN_BOOL(intern->iter->funcs->valid(intern->iter) == SUCCESS);
}

ZEND_METHOD(InternalIterator, rewind) {
  ZEND_PARSE_PARAMETERS_NONE();

  zend_internal_iterator *intern = zend_internal_iterator_fetch(ZEND_THIS);
  if (!intern) {
    RETURN_THROWS();
  }

  if (!intern->iter->funcs->rewind) {
    /* Allow calling rewind() if no iteration has happened yet,
     * even if the iterator does not support rewinding. */
    if (intern->iter->index != 0) {
      zend_throw_error(NULL, "Iterator does not support rewinding");
      RETURN_THROWS();
    }
    intern->iter->index = 0;
    return;
  }

  intern->iter->funcs->rewind(intern->iter);
  intern->iter->index = 0;
}

/* {{{ zend_register_interfaces */
ZEND_API void zend_register_interfaces(void)
{
  zend_class_entry ce;

  REGISTER_MAGIC_INTERFACE(traversable, Traversable);

  REGISTER_MAGIC_INTERFACE(aggregate, IteratorAggregate);
  REGISTER_MAGIC_IMPLEMENT(aggregate, traversable);

  REGISTER_MAGIC_INTERFACE(iterator, Iterator);
  REGISTER_MAGIC_IMPLEMENT(iterator, traversable);

  REGISTER_MAGIC_INTERFACE(serializable, Serializable);

  INIT_CLASS_ENTRY(ce, "ArrayAccess", class_ArrayAccess_methods);
  zend_ce_arrayaccess = zend_register_internal_interface(&ce);

  INIT_CLASS_ENTRY(ce, "Countable", class_Countable_methods);
  zend_ce_countable = zend_register_internal_interface(&ce);

  INIT_CLASS_ENTRY(ce, "Stringable", class_Stringable_methods);
  zend_ce_stringable = zend_register_internal_interface(&ce);

  INIT_CLASS_ENTRY(ce, "InternalIterator", class_InternalIterator_methods);
  zend_ce_internal_iterator = zend_register_internal_class(&ce);
  zend_class_implements(zend_ce_internal_iterator, 1, zend_ce_iterator);
  zend_ce_internal_iterator->ce_flags |= ZEND_ACC_FINAL;
  zend_ce_internal_iterator->create_object = zend_internal_iterator_create;
  zend_ce_internal_iterator->serialize = zend_class_serialize_deny;
  zend_ce_internal_iterator->unserialize = zend_class_unserialize_deny;

  memcpy(&zend_internal_iterator_handlers, zend_get_std_object_handlers(),
    sizeof(zend_object_handlers));
  zend_internal_iterator_handlers.free_obj = zend_internal_iterator_free;
}
/* }}} */

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Created: 2022-02-19 20:30