php-src/Zend/zend_generators.c
Nikita Popov ab75ed6ba9 Disallow closing a generator during its execution
If a generator is closed while it is running an E_WARNING is thrown and the
call is ignored. Maybe a fatal error should be thrown instead?
2012-06-23 16:08:15 +02:00

726 lines
22 KiB
C

/*
+----------------------------------------------------------------------+
| Zend Engine |
+----------------------------------------------------------------------+
| Copyright (c) 1998-2012 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: Nikita Popov <nikic@php.net> |
+----------------------------------------------------------------------+
*/
/* $Id$ */
#include "zend.h"
#include "zend_API.h"
#include "zend_interfaces.h"
#include "zend_generators.h"
ZEND_API zend_class_entry *zend_ce_generator;
static zend_object_handlers zend_generator_handlers;
void zend_generator_close(zend_generator *generator, zend_bool finished_execution TSRMLS_DC) /* {{{ */
{
if (generator->execute_data) {
zend_execute_data *execute_data = generator->execute_data;
if (!execute_data->symbol_table) {
zend_free_compiled_variables(execute_data->CVs, execute_data->op_array->last_var);
} else {
zend_clean_and_cache_symbol_table(execute_data->symbol_table TSRMLS_CC);
}
if (execute_data->current_this) {
zval_ptr_dtor(&execute_data->current_this);
}
if (execute_data->object) {
zval_ptr_dtor(&execute_data->object);
}
/* If the generator is closed before it can finish execution (reach
* a return statement) we have to free loop variables manually, as
* we don't know whether the SWITCH_FREE / FREE opcodes have run */
if (!finished_execution) {
zend_op_array *op_array = execute_data->op_array;
zend_uint op_num = execute_data->opline - op_array->opcodes;
int i;
for (i = 0; i < op_array->last_brk_cont; ++i) {
zend_brk_cont_element *brk_cont = op_array->brk_cont_array + i;
if (brk_cont->start < 0) {
continue;
} else if (brk_cont->start > op_num) {
break;
} else if (brk_cont->brk > op_num) {
zend_op *brk_opline = op_array->opcodes + brk_cont->brk;
switch (brk_opline->opcode) {
case ZEND_SWITCH_FREE:
{
temp_variable *var = (temp_variable *) ((char *) execute_data->Ts + brk_opline->op1.var);
zval_ptr_dtor(&var->var.ptr);
}
break;
case ZEND_FREE:
{
temp_variable *var = (temp_variable *) ((char *) execute_data->Ts + brk_opline->op1.var);
zval_dtor(&var->tmp_var);
}
break;
}
}
}
}
/* Clear any backed up stack arguments */
if (generator->backed_up_stack) {
zval **zvals = (zval **) generator->backed_up_stack;
size_t zval_num = generator->backed_up_stack_size / sizeof(zval *);
int i;
for (i = 0; i < zval_num; i++) {
zval_ptr_dtor(&zvals[i]);
}
efree(generator->backed_up_stack);
}
/* We have added an additional stack frame in prev_execute_data, so we
* have to free it. It also contains the arguments passed to the
* generator (for func_get_args) so those have to be freed too. */
{
zend_execute_data *prev_execute_data = execute_data->prev_execute_data;
void **arguments = prev_execute_data->function_state.arguments;
if (arguments) {
int arguments_count = (int) (zend_uintptr_t) *arguments;
zval **arguments_start = (zval **) (arguments - arguments_count);
int i;
for (i = 0; i < arguments_count; ++i) {
zval_ptr_dtor(arguments_start + i);
}
efree(arguments_start);
}
efree(prev_execute_data);
}
efree(execute_data);
generator->execute_data = NULL;
}
if (generator->value) {
zval_ptr_dtor(&generator->value);
generator->value = NULL;
}
if (generator->key) {
zval_ptr_dtor(&generator->key);
generator->key = NULL;
}
}
/* }}} */
static void zend_generator_free_storage(zend_generator *generator TSRMLS_DC) /* {{{ */
{
zend_generator_close(generator, 0 TSRMLS_CC);
zend_object_std_dtor(&generator->std TSRMLS_CC);
efree(generator);
}
/* }}} */
static void zend_generator_clone_storage(zend_generator *orig, zend_generator **clone_ptr) /* {{{ */
{
zend_generator *clone = emalloc(sizeof(zend_generator));
memcpy(clone, orig, sizeof(zend_generator));
if (orig->execute_data) {
/* Create a few shorter aliases to the old execution data */
zend_execute_data *execute_data = orig->execute_data;
zend_op_array *op_array = execute_data->op_array;
HashTable *symbol_table = execute_data->symbol_table;
/* Alloc separate execution context, as well as separate sections for
* compiled variables and temporary variables */
size_t execute_data_size = ZEND_MM_ALIGNED_SIZE(sizeof(zend_execute_data));
size_t CVs_size = ZEND_MM_ALIGNED_SIZE(sizeof(zval **) * op_array->last_var * (symbol_table ? 1 : 2));
size_t Ts_size = ZEND_MM_ALIGNED_SIZE(sizeof(temp_variable)) * op_array->T;
size_t total_size = execute_data_size + CVs_size + Ts_size;
clone->execute_data = emalloc(total_size);
/* Copy the zend_execute_data struct */
memcpy(clone->execute_data, execute_data, execute_data_size);
/* Set the pointers to the memory segments for the compiled and
* temporary variables (which are located after the execute_data) */
clone->execute_data->CVs = (zval ***) ((char *) clone->execute_data + execute_data_size);
clone->execute_data->Ts = (temp_variable *) ((char *) clone->execute_data->CVs + CVs_size);
/* Zero out the compiled variables section */
memset(clone->execute_data->CVs, 0, sizeof(zval **) * op_array->last_var);
if (!symbol_table) {
int i;
/* Copy compiled variables */
for (i = 0; i < op_array->last_var; i++) {
if (execute_data->CVs[i]) {
clone->execute_data->CVs[i] = (zval **) clone->execute_data->CVs + op_array->last_var + i;
*clone->execute_data->CVs[i] = (zval *) orig->execute_data->CVs[op_array->last_var + i];
Z_ADDREF_PP(clone->execute_data->CVs[i]);
}
}
} else {
/* Copy symbol table */
ALLOC_HASHTABLE(clone->execute_data->symbol_table);
zend_hash_init(clone->execute_data->symbol_table, zend_hash_num_elements(symbol_table), NULL, ZVAL_PTR_DTOR, 0);
zend_hash_copy(clone->execute_data->symbol_table, symbol_table, (copy_ctor_func_t) zval_add_ref, NULL, sizeof(zval *));
/* Update zval** pointers for compiled variables */
{
int i;
for (i = 0; i < op_array->last_var; i++) {
if (zend_hash_quick_find(clone->execute_data->symbol_table, op_array->vars[i].name, op_array->vars[i].name_len + 1, op_array->vars[i].hash_value, (void **) &clone->execute_data->CVs[i]) == FAILURE) {
clone->execute_data->CVs[i] = NULL;
}
}
}
}
/* Copy the temporary variables */
memcpy(clone->execute_data->Ts, orig->execute_data->Ts, Ts_size);
/* Add references to loop variables */
{
zend_uint op_num = execute_data->opline - op_array->opcodes;
int i;
for (i = 0; i < op_array->last_brk_cont; ++i) {
zend_brk_cont_element *brk_cont = op_array->brk_cont_array + i;
if (brk_cont->start < 0) {
continue;
} else if (brk_cont->start > op_num) {
break;
} else if (brk_cont->brk > op_num) {
zend_op *brk_opline = op_array->opcodes + brk_cont->brk;
if (brk_opline->opcode == ZEND_SWITCH_FREE) {
temp_variable *var = (temp_variable *) ((char *) execute_data->Ts + brk_opline->op1.var);
Z_ADDREF_P(var->var.ptr);
}
}
}
}
if (orig->backed_up_stack) {
/* Copy backed up stack */
clone->backed_up_stack = emalloc(orig->backed_up_stack_size);
memcpy(clone->backed_up_stack, orig->backed_up_stack, orig->backed_up_stack_size);
/* Add refs to stack variables */
{
zval **zvals = (zval **) orig->backed_up_stack;
size_t zval_num = orig->backed_up_stack_size / sizeof(zval *);
int i;
for (i = 0; i < zval_num; i++) {
Z_ADDREF_P(zvals[i]);
}
}
}
/* Update the send_target to use the temporary variable with the same
* offset as the original generator, but in our temporary variable
* memory segment. */
if (orig->send_target) {
size_t offset = (char *) orig->send_target - (char *) execute_data->Ts;
clone->send_target = (temp_variable *) (
(char *) clone->execute_data->Ts + offset
);
Z_ADDREF_P(clone->send_target->var.ptr);
}
if (execute_data->current_this) {
Z_ADDREF_P(execute_data->current_this);
}
if (execute_data->object) {
Z_ADDREF_P(execute_data->object);
}
/* Prev execute data contains an additional stack frame (for proper)
* backtraces) which has to be copied. */
clone->execute_data->prev_execute_data = emalloc(sizeof(zend_execute_data));
memcpy(clone->execute_data->prev_execute_data, execute_data->prev_execute_data, sizeof(zend_execute_data));
/* It also contains the arguments passed to the generator, which also
* have to be copied */
if (execute_data->prev_execute_data->function_state.arguments) {
clone->execute_data->prev_execute_data->function_state.arguments
= zend_copy_arguments(execute_data->prev_execute_data->function_state.arguments);
}
}
/* The value and key are known not to be references, so simply add refs */
if (orig->value) {
Z_ADDREF_P(orig->value);
}
if (orig->key) {
Z_ADDREF_P(orig->key);
}
*clone_ptr = clone;
}
/* }}} */
static zend_object_value zend_generator_create(zend_class_entry *class_type TSRMLS_DC) /* {{{ */
{
zend_generator *generator;
zend_object_value object;
generator = emalloc(sizeof(zend_generator));
memset(generator, 0, sizeof(zend_generator));
/* The key will be incremented on first use, so it'll start at 0 */
generator->largest_used_integer_key = -1;
generator->is_currently_running = 0;
zend_object_std_init(&generator->std, class_type TSRMLS_CC);
object.handle = zend_objects_store_put(generator, NULL,
(zend_objects_free_object_storage_t) zend_generator_free_storage,
(zend_objects_store_clone_t) zend_generator_clone_storage
TSRMLS_CC
);
object.handlers = &zend_generator_handlers;
return object;
}
/* }}} */
static zend_function *zend_generator_get_constructor(zval *object TSRMLS_DC) /* {{{ */
{
zend_error(E_RECOVERABLE_ERROR, "The \"Generator\" class is reserved for internal use and cannot be manually instantiated");
return NULL;
}
/* }}} */
static void zend_generator_resume(zend_generator *generator TSRMLS_DC) /* {{{ */
{
/* The generator is already closed, thus can't resume */
if (!generator->execute_data) {
return;
}
{
/* Backup executor globals */
zval **original_return_value_ptr_ptr = EG(return_value_ptr_ptr);
zend_execute_data *original_execute_data = EG(current_execute_data);
zend_op **original_opline_ptr = EG(opline_ptr);
zend_op_array *original_active_op_array = EG(active_op_array);
HashTable *original_active_symbol_table = EG(active_symbol_table);
zval *original_This = EG(This);
zend_class_entry *original_scope = EG(scope);
zend_class_entry *original_called_scope = EG(called_scope);
zend_bool original_is_currently_running = generator->is_currently_running;
/* Remember the current stack position so we can back up pushed args */
generator->original_stack_top = zend_vm_stack_top(TSRMLS_C);
/* If there is a backed up stack copy it to the VM stack */
if (generator->backed_up_stack) {
void *stack = zend_vm_stack_alloc(generator->backed_up_stack_size TSRMLS_CC);
memcpy(stack, generator->backed_up_stack, generator->backed_up_stack_size);
efree(generator->backed_up_stack);
generator->backed_up_stack = NULL;
}
/* We (mis)use the return_value_ptr_ptr to provide the generator object
* to the executor, so YIELD will be able to set the yielded value */
EG(return_value_ptr_ptr) = (zval **) generator;
/* Set executor globals */
EG(current_execute_data) = generator->execute_data;
EG(opline_ptr) = &generator->execute_data->opline;
EG(active_op_array) = generator->execute_data->op_array;
EG(active_symbol_table) = generator->execute_data->symbol_table;
EG(This) = generator->execute_data->current_this;
EG(scope) = generator->execute_data->current_scope;
EG(called_scope) = generator->execute_data->current_called_scope;
generator->is_currently_running = 1;
/* We want the backtrace to look as if the generator function was
* called from whatever method we are current running (e.g. next()).
* The first prev_execute_data contains an additional stack frame,
* which makes the generator function show up in the backtrace and
* makes the arguments available to func_get_args(). So we have to
* set the prev_execute_data of that prev_execute_data :) */
generator->execute_data->prev_execute_data->prev_execute_data = original_execute_data;
/* Go to next opcode (we don't want to run the last one again) */
generator->execute_data->opline++;
/* Resume execution */
execute_ex(generator->execute_data TSRMLS_CC);
/* Restore executor globals */
EG(return_value_ptr_ptr) = original_return_value_ptr_ptr;
EG(current_execute_data) = original_execute_data;
EG(opline_ptr) = original_opline_ptr;
EG(active_op_array) = original_active_op_array;
EG(active_symbol_table) = original_active_symbol_table;
EG(This) = original_This;
EG(scope) = original_scope;
EG(called_scope) = original_called_scope;
generator->is_currently_running = original_is_currently_running;
/* The stack top before and after the execution differ, i.e. there are
* arguments pushed to the stack. */
if (generator->original_stack_top != zend_vm_stack_top(TSRMLS_C)) {
generator->backed_up_stack_size = (zend_vm_stack_top(TSRMLS_C) - generator->original_stack_top) * sizeof(void *);
generator->backed_up_stack = emalloc(generator->backed_up_stack_size);
memcpy(generator->backed_up_stack, generator->original_stack_top, generator->backed_up_stack_size);
zend_vm_stack_free(generator->original_stack_top TSRMLS_CC);
}
}
}
/* }}} */
static void zend_generator_ensure_initialized(zend_generator *generator TSRMLS_DC) /* {{{ */
{
if (!generator->value) {
zend_generator_resume(generator TSRMLS_CC);
}
}
/* }}} */
/* {{{ proto void Generator::rewind()
* Rewind the generator */
ZEND_METHOD(Generator, rewind)
{
zend_generator *generator;
if (zend_parse_parameters_none() == FAILURE) {
return;
}
generator = (zend_generator *) zend_object_store_get_object(getThis() TSRMLS_CC);
zend_generator_ensure_initialized(generator TSRMLS_CC);
/* Generators aren't rewindable, so rewind() only has to make sure that
* the generator is initialized, nothing more */
}
/* }}} */
/* {{{ proto bool Generator::valid()
* Check whether the generator is valid */
ZEND_METHOD(Generator, valid)
{
zend_generator *generator;
if (zend_parse_parameters_none() == FAILURE) {
return;
}
generator = (zend_generator *) zend_object_store_get_object(getThis() TSRMLS_CC);
zend_generator_ensure_initialized(generator TSRMLS_CC);
RETURN_BOOL(generator->value != NULL);
}
/* }}} */
/* {{{ proto mixed Generator::current()
* Get the current value */
ZEND_METHOD(Generator, current)
{
zend_generator *generator;
if (zend_parse_parameters_none() == FAILURE) {
return;
}
generator = (zend_generator *) zend_object_store_get_object(getThis() TSRMLS_CC);
zend_generator_ensure_initialized(generator TSRMLS_CC);
if (generator->value) {
RETURN_ZVAL(generator->value, 1, 0);
}
}
/* }}} */
/* {{{ proto mixed Generator::key()
* Get the current key */
ZEND_METHOD(Generator, key)
{
zend_generator *generator;
if (zend_parse_parameters_none() == FAILURE) {
return;
}
generator = (zend_generator *) zend_object_store_get_object(getThis() TSRMLS_CC);
zend_generator_ensure_initialized(generator TSRMLS_CC);
if (generator->key) {
RETURN_ZVAL(generator->key, 1, 0);
}
}
/* }}} */
/* {{{ proto void Generator::next()
* Advances the generator */
ZEND_METHOD(Generator, next)
{
zend_generator *generator;
if (zend_parse_parameters_none() == FAILURE) {
return;
}
generator = (zend_generator *) zend_object_store_get_object(getThis() TSRMLS_CC);
zend_generator_ensure_initialized(generator TSRMLS_CC);
zend_generator_resume(generator TSRMLS_CC);
}
/* }}} */
/* {{{ proto mixed Generator::send()
* Sends a value to the generator */
ZEND_METHOD(Generator, send)
{
zval *value;
zend_generator *generator;
if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "z", &value) == FAILURE) {
return;
}
generator = (zend_generator *) zend_object_store_get_object(getThis() TSRMLS_CC);
zend_generator_ensure_initialized(generator TSRMLS_CC);
/* The generator is already closed, thus can't send anything */
if (!generator->execute_data) {
return;
}
/* The sent value was initialized to NULL, so dtor that */
zval_ptr_dtor(&generator->send_target->var.ptr);
/* Set new sent value */
Z_ADDREF_P(value);
generator->send_target->var.ptr = value;
generator->send_target->var.ptr_ptr = &value;
zend_generator_resume(generator TSRMLS_CC);
if (generator->value) {
RETURN_ZVAL(generator->value, 1, 0);
}
}
/* {{{ proto void Generator::close()
* Closes the generator */
ZEND_METHOD(Generator, close)
{
zend_generator *generator;
if (zend_parse_parameters_none() == FAILURE) {
return;
}
generator = (zend_generator *) zend_object_store_get_object(getThis() TSRMLS_CC);
if (generator->is_currently_running) {
zend_error(E_WARNING, "A generator cannot be closed while it is running");
return;
}
zend_generator_close(generator, 0 TSRMLS_CC);
}
/* }}} */
/* get_iterator implementation */
typedef struct _zend_generator_iterator {
zend_object_iterator intern;
/* The generator object zval has to be stored, because the iterator is
* holding a ref to it, which has to be dtored. */
zval *object;
} zend_generator_iterator;
static void zend_generator_iterator_dtor(zend_object_iterator *iterator TSRMLS_DC) /* {{{ */
{
zval *object = ((zend_generator_iterator *) iterator)->object;
zval_ptr_dtor(&object);
efree(iterator);
}
/* }}} */
static int zend_generator_iterator_valid(zend_object_iterator *iterator TSRMLS_DC) /* {{{ */
{
zend_generator *generator = (zend_generator *) iterator->data;
zend_generator_ensure_initialized(generator TSRMLS_CC);
return generator->value != NULL ? SUCCESS : FAILURE;
}
/* }}} */
static void zend_generator_iterator_get_data(zend_object_iterator *iterator, zval ***data TSRMLS_DC) /* {{{ */
{
zend_generator *generator = (zend_generator *) iterator->data;
zend_generator_ensure_initialized(generator TSRMLS_CC);
if (generator->value) {
*data = &generator->value;
} else {
*data = NULL;
}
}
/* }}} */
static int zend_generator_iterator_get_key(zend_object_iterator *iterator, char **str_key, uint *str_key_len, ulong *int_key TSRMLS_DC) /* {{{ */
{
zend_generator *generator = (zend_generator *) iterator->data;
zend_generator_ensure_initialized(generator TSRMLS_CC);
if (!generator->key) {
return HASH_KEY_NON_EXISTANT;
}
if (Z_TYPE_P(generator->key) == IS_LONG) {
*int_key = Z_LVAL_P(generator->key);
return HASH_KEY_IS_LONG;
}
if (Z_TYPE_P(generator->key) == IS_STRING) {
*str_key = estrndup(Z_STRVAL_P(generator->key), Z_STRLEN_P(generator->key));
*str_key_len = Z_STRLEN_P(generator->key) + 1;
return HASH_KEY_IS_STRING;
}
/* Waiting for Etienne's patch to allow arbitrary zval keys. Until then
* error out on non-int and non-string keys. */
zend_error_noreturn(E_ERROR, "Currently only int and string keys can be yielded");
}
/* }}} */
static void zend_generator_iterator_move_forward(zend_object_iterator *iterator TSRMLS_DC) /* {{{ */
{
zend_generator *generator = (zend_generator *) iterator->data;
zend_generator_ensure_initialized(generator TSRMLS_CC);
zend_generator_resume(generator TSRMLS_CC);
}
/* }}} */
static zend_object_iterator_funcs zend_generator_iterator_functions = {
zend_generator_iterator_dtor,
zend_generator_iterator_valid,
zend_generator_iterator_get_data,
zend_generator_iterator_get_key,
zend_generator_iterator_move_forward,
NULL
};
zend_object_iterator *zend_generator_get_iterator(zend_class_entry *ce, zval *object, int by_ref TSRMLS_DC) /* {{{ */
{
zend_generator_iterator *iterator;
zend_generator *generator;
if (by_ref) {
zend_error(E_ERROR, "By reference iteration of generators is currently not supported");
}
generator = (zend_generator *) zend_object_store_get_object(object TSRMLS_CC);
iterator = emalloc(sizeof(zend_generator_iterator));
iterator->intern.funcs = &zend_generator_iterator_functions;
iterator->intern.data = (void *) generator;
/* We have to keep a reference to the generator object zval around,
* otherwise the generator may be destroyed during iteration. */
Z_ADDREF_P(object);
iterator->object = object;
return (zend_object_iterator *) iterator;
}
/* }}} */
ZEND_BEGIN_ARG_INFO(arginfo_generator_void, 0)
ZEND_END_ARG_INFO()
ZEND_BEGIN_ARG_INFO_EX(arginfo_generator_send, 0, 0, 1)
ZEND_ARG_INFO(0, value)
ZEND_END_ARG_INFO()
static const zend_function_entry generator_functions[] = {
ZEND_ME(Generator, rewind, arginfo_generator_void, ZEND_ACC_PUBLIC)
ZEND_ME(Generator, valid, arginfo_generator_void, ZEND_ACC_PUBLIC)
ZEND_ME(Generator, current, arginfo_generator_void, ZEND_ACC_PUBLIC)
ZEND_ME(Generator, key, arginfo_generator_void, ZEND_ACC_PUBLIC)
ZEND_ME(Generator, next, arginfo_generator_void, ZEND_ACC_PUBLIC)
ZEND_ME(Generator, send, arginfo_generator_send, ZEND_ACC_PUBLIC)
ZEND_ME(Generator, close, arginfo_generator_void, ZEND_ACC_PUBLIC)
ZEND_FE_END
};
void zend_register_generator_ce(TSRMLS_D) /* {{{ */
{
zend_class_entry ce;
INIT_CLASS_ENTRY(ce, "Generator", generator_functions);
zend_ce_generator = zend_register_internal_class(&ce TSRMLS_CC);
zend_ce_generator->ce_flags |= ZEND_ACC_FINAL_CLASS;
zend_ce_generator->create_object = zend_generator_create;
zend_ce_generator->get_iterator = zend_generator_get_iterator;
zend_class_implements(zend_ce_generator TSRMLS_CC, 1, zend_ce_iterator);
memcpy(&zend_generator_handlers, zend_get_std_object_handlers(), sizeof(zend_object_handlers));
zend_generator_handlers.get_constructor = zend_generator_get_constructor;
zend_generator_handlers.clone_obj = zend_objects_store_clone_obj;
}
/* }}} */
/*
* Local variables:
* tab-width: 4
* c-basic-offset: 4
* indent-tabs-mode: t
* End:
*/