php-src/Zend/zend_weakrefs.c
2021-03-30 20:20:54 +03:00

633 lines
19 KiB
C

/*
+----------------------------------------------------------------------+
| Copyright (c) The PHP Group |
+----------------------------------------------------------------------+
| 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: krakjoe@php.net |
+----------------------------------------------------------------------+
*/
#include "zend.h"
#include "zend_interfaces.h"
#include "zend_objects_API.h"
#include "zend_weakrefs.h"
#include "zend_weakrefs_arginfo.h"
typedef struct _zend_weakref {
zend_object *referent;
zend_object std;
} zend_weakref;
typedef struct _zend_weakmap {
HashTable ht;
zend_object std;
} zend_weakmap;
typedef struct _zend_weakmap_iterator {
zend_object_iterator it;
uint32_t ht_iter;
} zend_weakmap_iterator;
/* The EG(weakrefs) ht is a map from object address a tagged pointer, that may be one of
* zend_weakref*, zend_weakmap* or HashTable*. */
#define ZEND_WEAKREF_TAG_REF 0
#define ZEND_WEAKREF_TAG_MAP 1
#define ZEND_WEAKREF_TAG_HT 2
#define ZEND_WEAKREF_GET_TAG(p) (((uintptr_t) (p)) & 3)
#define ZEND_WEAKREF_GET_PTR(p) ((void *) (((uintptr_t) (p)) & ~3))
#define ZEND_WEAKREF_ENCODE(p, t) ((void *) (((uintptr_t) (p)) | (t)))
zend_class_entry *zend_ce_weakref;
zend_class_entry *zend_ce_weakmap;
static zend_object_handlers zend_weakref_handlers;
static zend_object_handlers zend_weakmap_handlers;
#define zend_weakref_from(o) ((zend_weakref*)(((char*) o) - XtOffsetOf(zend_weakref, std)))
#define zend_weakref_fetch(z) zend_weakref_from(Z_OBJ_P(z))
#define zend_weakmap_from(o) ((zend_weakmap*)(((char*) o) - XtOffsetOf(zend_weakmap, std)))
#define zend_weakmap_fetch(z) zend_weakmap_from(Z_OBJ_P(z))
static inline void zend_weakref_unref_single(
void *ptr, uintptr_t tag, zend_ulong obj_addr)
{
if (tag == ZEND_WEAKREF_TAG_REF) {
zend_weakref *wr = ptr;
wr->referent = NULL;
} else {
ZEND_ASSERT(tag == ZEND_WEAKREF_TAG_MAP);
zend_weakmap *wm = ptr;
zend_hash_index_del(&wm->ht, obj_addr);
}
}
static void zend_weakref_unref(zend_ulong obj_addr, void *tagged_ptr) {
void *ptr = ZEND_WEAKREF_GET_PTR(tagged_ptr);
uintptr_t tag = ZEND_WEAKREF_GET_TAG(tagged_ptr);
if (tag == ZEND_WEAKREF_TAG_HT) {
HashTable *ht = ptr;
ZEND_HASH_FOREACH_PTR(ht, tagged_ptr) {
zend_weakref_unref_single(
ZEND_WEAKREF_GET_PTR(tagged_ptr), ZEND_WEAKREF_GET_TAG(tagged_ptr), obj_addr);
} ZEND_HASH_FOREACH_END();
zend_hash_destroy(ht);
FREE_HASHTABLE(ht);
} else {
zend_weakref_unref_single(ptr, tag, obj_addr);
}
}
static void zend_weakref_register(zend_object *object, void *payload) {
GC_ADD_FLAGS(object, IS_OBJ_WEAKLY_REFERENCED);
zend_ulong obj_addr = (zend_ulong) object;
zval *zv = zend_hash_index_find(&EG(weakrefs), obj_addr);
if (!zv) {
zend_hash_index_add_new_ptr(&EG(weakrefs), obj_addr, payload);
return;
}
void *tagged_ptr = Z_PTR_P(zv);
if (ZEND_WEAKREF_GET_TAG(tagged_ptr) == ZEND_WEAKREF_TAG_HT) {
HashTable *ht = ZEND_WEAKREF_GET_PTR(tagged_ptr);
zend_hash_index_add_new_ptr(ht, (zend_ulong) payload, payload);
return;
}
/* Convert simple pointer to hashtable. */
HashTable *ht = emalloc(sizeof(HashTable));
zend_hash_init(ht, 0, NULL, NULL, 0);
zend_hash_index_add_new_ptr(ht, (zend_ulong) tagged_ptr, tagged_ptr);
zend_hash_index_add_new_ptr(ht, (zend_ulong) payload, payload);
zend_hash_index_update_ptr(
&EG(weakrefs), obj_addr, ZEND_WEAKREF_ENCODE(ht, ZEND_WEAKREF_TAG_HT));
}
static void zend_weakref_unregister(zend_object *object, void *payload) {
zend_ulong obj_addr = (zend_ulong) object;
void *tagged_ptr = zend_hash_index_find_ptr(&EG(weakrefs), obj_addr);
ZEND_ASSERT(tagged_ptr && "Weakref not registered?");
void *ptr = ZEND_WEAKREF_GET_PTR(tagged_ptr);
uintptr_t tag = ZEND_WEAKREF_GET_TAG(tagged_ptr);
if (tag != ZEND_WEAKREF_TAG_HT) {
ZEND_ASSERT(tagged_ptr == payload);
zend_hash_index_del(&EG(weakrefs), obj_addr);
GC_DEL_FLAGS(object, IS_OBJ_WEAKLY_REFERENCED);
/* Do this last, as it may destroy the object. */
zend_weakref_unref_single(ptr, tag, obj_addr);
return;
}
HashTable *ht = ptr;
tagged_ptr = zend_hash_index_find_ptr(ht, (zend_ulong) payload);
ZEND_ASSERT(tagged_ptr && "Weakref not registered?");
ZEND_ASSERT(tagged_ptr == payload);
zend_hash_index_del(ht, (zend_ulong) payload);
if (zend_hash_num_elements(ht) == 0) {
GC_DEL_FLAGS(object, IS_OBJ_WEAKLY_REFERENCED);
zend_hash_destroy(ht);
FREE_HASHTABLE(ht);
zend_hash_index_del(&EG(weakrefs), obj_addr);
}
/* Do this last, as it may destroy the object. */
zend_weakref_unref_single(
ZEND_WEAKREF_GET_PTR(payload), ZEND_WEAKREF_GET_TAG(payload), obj_addr);
}
void zend_weakrefs_init(void) {
zend_hash_init(&EG(weakrefs), 8, NULL, NULL, 0);
}
void zend_weakrefs_notify(zend_object *object) {
/* Annoyingly we can't use the HT destructor here, because we need access to the key (which
* is the object address), which is not provided to the dtor. */
zend_ulong obj_addr = (zend_ulong) object;
void *tagged_ptr = zend_hash_index_find_ptr(&EG(weakrefs), obj_addr);
#if ZEND_DEBUG
ZEND_ASSERT(tagged_ptr && "Tracking of the IS_OBJ_WEAKLY_REFERENCE flag should be precise");
#endif
if (tagged_ptr) {
zend_weakref_unref(obj_addr, tagged_ptr);
zend_hash_index_del(&EG(weakrefs), obj_addr);
}
}
void zend_weakrefs_shutdown(void) {
zend_ulong obj_addr;
void *tagged_ptr;
ZEND_HASH_FOREACH_NUM_KEY_PTR(&EG(weakrefs), obj_addr, tagged_ptr) {
zend_weakref_unref(obj_addr, tagged_ptr);
} ZEND_HASH_FOREACH_END();
zend_hash_destroy(&EG(weakrefs));
}
static zend_object* zend_weakref_new(zend_class_entry *ce) {
zend_weakref *wr = zend_object_alloc(sizeof(zend_weakref), zend_ce_weakref);
zend_object_std_init(&wr->std, zend_ce_weakref);
wr->std.handlers = &zend_weakref_handlers;
return &wr->std;
}
static zend_always_inline bool zend_weakref_find(zend_object *referent, zval *return_value) {
void *tagged_ptr = zend_hash_index_find_ptr(&EG(weakrefs), (zend_ulong) referent);
if (!tagged_ptr) {
return 0;
}
void *ptr = ZEND_WEAKREF_GET_PTR(tagged_ptr);
uintptr_t tag = ZEND_WEAKREF_GET_TAG(tagged_ptr);
if (tag == ZEND_WEAKREF_TAG_REF) {
zend_weakref *wr;
found_weakref:
wr = ptr;
RETVAL_OBJ_COPY(&wr->std);
return 1;
}
if (tag == ZEND_WEAKREF_TAG_HT) {
ZEND_HASH_FOREACH(ptr, tagged_ptr) {
if (ZEND_WEAKREF_GET_TAG(tagged_ptr) == ZEND_WEAKREF_TAG_REF) {
ptr = ZEND_WEAKREF_GET_PTR(tagged_ptr);
goto found_weakref;
}
} ZEND_HASH_FOREACH_END();
}
return 0;
}
static zend_always_inline void zend_weakref_create(zend_object *referent, zval *return_value) {
zend_weakref *wr;
object_init_ex(return_value, zend_ce_weakref);
wr = zend_weakref_fetch(return_value);
wr->referent = referent;
zend_weakref_register(wr->referent, ZEND_WEAKREF_ENCODE(wr, ZEND_WEAKREF_TAG_REF));
}
static zend_always_inline void zend_weakref_get(zval *weakref, zval *return_value) {
zend_weakref *wr = zend_weakref_fetch(weakref);
if (wr->referent) {
RETVAL_OBJ_COPY(wr->referent);
}
}
static void zend_weakref_free(zend_object *zo) {
zend_weakref *wr = zend_weakref_from(zo);
if (wr->referent) {
zend_weakref_unregister(wr->referent, ZEND_WEAKREF_ENCODE(wr, ZEND_WEAKREF_TAG_REF));
}
zend_object_std_dtor(&wr->std);
}
ZEND_COLD ZEND_METHOD(WeakReference, __construct)
{
zend_throw_error(NULL, "Direct instantiation of WeakReference is not allowed, use WeakReference::create instead");
}
ZEND_METHOD(WeakReference, create)
{
zend_object *referent;
ZEND_PARSE_PARAMETERS_START(1,1)
Z_PARAM_OBJ(referent)
ZEND_PARSE_PARAMETERS_END();
if (zend_weakref_find(referent, return_value)) {
return;
}
zend_weakref_create(referent, return_value);
}
ZEND_METHOD(WeakReference, get)
{
ZEND_PARSE_PARAMETERS_NONE();
zend_weakref_get(getThis(), return_value);
}
static zend_object *zend_weakmap_create_object(zend_class_entry *ce)
{
zend_weakmap *wm = zend_object_alloc(sizeof(zend_weakmap), ce);
zend_object_std_init(&wm->std, ce);
wm->std.handlers = &zend_weakmap_handlers;
zend_hash_init(&wm->ht, 0, NULL, ZVAL_PTR_DTOR, 0);
return &wm->std;
}
static void zend_weakmap_free_obj(zend_object *object)
{
zend_weakmap *wm = zend_weakmap_from(object);
zend_ulong obj_addr;
ZEND_HASH_FOREACH_NUM_KEY(&wm->ht, obj_addr) {
zend_weakref_unregister(
(zend_object *) obj_addr, ZEND_WEAKREF_ENCODE(wm, ZEND_WEAKREF_TAG_MAP));
} ZEND_HASH_FOREACH_END();
zend_hash_destroy(&wm->ht);
zend_object_std_dtor(&wm->std);
}
static zval *zend_weakmap_read_dimension(zend_object *object, zval *offset, int type, zval *rv)
{
if (offset == NULL) {
zend_throw_error(NULL, "Cannot append to WeakMap");
return NULL;
}
if (Z_TYPE_P(offset) != IS_OBJECT) {
zend_type_error("WeakMap key must be an object");
return NULL;
}
zend_weakmap *wm = zend_weakmap_from(object);
zend_object *obj_key = Z_OBJ_P(offset);
zval *zv = zend_hash_index_find(&wm->ht, (zend_ulong) obj_key);
if (zv == NULL) {
if (type != BP_VAR_IS) {
zend_throw_error(NULL,
"Object %s#%d not contained in WeakMap", ZSTR_VAL(obj_key->ce->name), obj_key->handle);
return NULL;
}
return NULL;
}
if (type == BP_VAR_W || type == BP_VAR_RW) {
ZVAL_MAKE_REF(zv);
}
return zv;
}
static void zend_weakmap_write_dimension(zend_object *object, zval *offset, zval *value)
{
if (offset == NULL) {
zend_throw_error(NULL, "Cannot append to WeakMap");
return;
}
if (Z_TYPE_P(offset) != IS_OBJECT) {
zend_type_error("WeakMap key must be an object");
return;
}
zend_weakmap *wm = zend_weakmap_from(object);
zend_object *obj_key = Z_OBJ_P(offset);
Z_TRY_ADDREF_P(value);
zval *zv = zend_hash_index_find(&wm->ht, (zend_ulong) obj_key);
if (zv) {
zval_ptr_dtor(zv);
ZVAL_COPY_VALUE(zv, value);
return;
}
zend_weakref_register(obj_key, ZEND_WEAKREF_ENCODE(wm, ZEND_WEAKREF_TAG_MAP));
zend_hash_index_add_new(&wm->ht, (zend_ulong) obj_key, value);
}
/* int return and check_empty due to Object Handler API */
static int zend_weakmap_has_dimension(zend_object *object, zval *offset, int check_empty)
{
if (Z_TYPE_P(offset) != IS_OBJECT) {
zend_type_error("WeakMap key must be an object");
return 0;
}
zend_weakmap *wm = zend_weakmap_from(object);
zval *zv = zend_hash_index_find(&wm->ht, (zend_ulong) Z_OBJ_P(offset));
if (!zv) {
return 0;
}
if (check_empty) {
return i_zend_is_true(zv);
}
return Z_TYPE_P(zv) != IS_NULL;
}
static void zend_weakmap_unset_dimension(zend_object *object, zval *offset)
{
if (Z_TYPE_P(offset) != IS_OBJECT) {
zend_type_error("WeakMap key must be an object");
return;
}
zend_weakmap *wm = zend_weakmap_from(object);
zend_object *obj_key = Z_OBJ_P(offset);
if (!zend_hash_index_exists(&wm->ht, (zend_ulong) Z_OBJ_P(offset))) {
/* Object not in WeakMap, do nothing. */
return;
}
zend_weakref_unregister(obj_key, ZEND_WEAKREF_ENCODE(wm, ZEND_WEAKREF_TAG_MAP));
}
static int zend_weakmap_count_elements(zend_object *object, zend_long *count)
{
zend_weakmap *wm = zend_weakmap_from(object);
*count = zend_hash_num_elements(&wm->ht);
return SUCCESS;
}
static HashTable *zend_weakmap_get_properties_for(zend_object *object, zend_prop_purpose purpose)
{
if (purpose != ZEND_PROP_PURPOSE_DEBUG) {
return NULL;
}
zend_weakmap *wm = zend_weakmap_from(object);
HashTable *ht;
ALLOC_HASHTABLE(ht);
zend_hash_init(ht, zend_hash_num_elements(&wm->ht), NULL, ZVAL_PTR_DTOR, 0);
zend_ulong obj_addr;
zval *val;
ZEND_HASH_FOREACH_NUM_KEY_VAL(&wm->ht, obj_addr, val) {
zend_object *obj = (zend_object*)obj_addr;
zval pair;
array_init(&pair);
GC_ADDREF(obj);
add_assoc_object(&pair, "key", obj);
Z_TRY_ADDREF_P(val);
add_assoc_zval(&pair, "value", val);
zend_hash_next_index_insert_new(ht, &pair);
} ZEND_HASH_FOREACH_END();
return ht;
}
static HashTable *zend_weakmap_get_gc(zend_object *object, zval **table, int *n)
{
zend_weakmap *wm = zend_weakmap_from(object);
*table = NULL;
*n = 0;
return &wm->ht;
}
static zend_object *zend_weakmap_clone_obj(zend_object *old_object)
{
zend_object *new_object = zend_weakmap_create_object(zend_ce_weakmap);
zend_weakmap *old_wm = zend_weakmap_from(old_object);
zend_weakmap *new_wm = zend_weakmap_from(new_object);
zend_hash_copy(&new_wm->ht, &old_wm->ht, NULL);
zend_ulong obj_addr;
zval *val;
ZEND_HASH_FOREACH_NUM_KEY_VAL(&new_wm->ht, obj_addr, val) {
zend_weakref_register(
(zend_object *) obj_addr, ZEND_WEAKREF_ENCODE(new_wm, ZEND_WEAKREF_TAG_MAP));
zval_add_ref(val);
} ZEND_HASH_FOREACH_END();
return new_object;
}
static HashPosition *zend_weakmap_iterator_get_pos_ptr(zend_weakmap_iterator *iter) {
ZEND_ASSERT(iter->ht_iter != (uint32_t) -1);
return &EG(ht_iterators)[iter->ht_iter].pos;
}
static void zend_weakmap_iterator_dtor(zend_object_iterator *obj_iter)
{
zend_weakmap_iterator *iter = (zend_weakmap_iterator *) obj_iter;
zend_hash_iterator_del(iter->ht_iter);
zval_ptr_dtor(&iter->it.data);
}
static int zend_weakmap_iterator_valid(zend_object_iterator *obj_iter)
{
zend_weakmap_iterator *iter = (zend_weakmap_iterator *) obj_iter;
zend_weakmap *wm = zend_weakmap_fetch(&iter->it.data);
HashPosition *pos = zend_weakmap_iterator_get_pos_ptr(iter);
return zend_hash_has_more_elements_ex(&wm->ht, pos);
}
static zval *zend_weakmap_iterator_get_current_data(zend_object_iterator *obj_iter)
{
zend_weakmap_iterator *iter = (zend_weakmap_iterator *) obj_iter;
zend_weakmap *wm = zend_weakmap_fetch(&iter->it.data);
HashPosition *pos = zend_weakmap_iterator_get_pos_ptr(iter);
return zend_hash_get_current_data_ex(&wm->ht, pos);
}
static void zend_weakmap_iterator_get_current_key(zend_object_iterator *obj_iter, zval *key)
{
zend_weakmap_iterator *iter = (zend_weakmap_iterator *) obj_iter;
zend_weakmap *wm = zend_weakmap_fetch(&iter->it.data);
HashPosition *pos = zend_weakmap_iterator_get_pos_ptr(iter);
zend_string *string_key;
zend_ulong num_key;
int key_type = zend_hash_get_current_key_ex(&wm->ht, &string_key, &num_key, pos);
if (key_type != HASH_KEY_IS_LONG) {
ZEND_ASSERT(0 && "Must have integer key");
}
ZVAL_OBJ_COPY(key, (zend_object *) num_key);
}
static void zend_weakmap_iterator_move_forward(zend_object_iterator *obj_iter)
{
zend_weakmap_iterator *iter = (zend_weakmap_iterator *) obj_iter;
zend_weakmap *wm = zend_weakmap_fetch(&iter->it.data);
HashPosition *pos = zend_weakmap_iterator_get_pos_ptr(iter);
zend_hash_move_forward_ex(&wm->ht, pos);
}
static void zend_weakmap_iterator_rewind(zend_object_iterator *obj_iter)
{
zend_weakmap_iterator *iter = (zend_weakmap_iterator *) obj_iter;
zend_weakmap *wm = zend_weakmap_fetch(&iter->it.data);
HashPosition *pos = zend_weakmap_iterator_get_pos_ptr(iter);
zend_hash_internal_pointer_reset_ex(&wm->ht, pos);
}
static const zend_object_iterator_funcs zend_weakmap_iterator_funcs = {
zend_weakmap_iterator_dtor,
zend_weakmap_iterator_valid,
zend_weakmap_iterator_get_current_data,
zend_weakmap_iterator_get_current_key,
zend_weakmap_iterator_move_forward,
zend_weakmap_iterator_rewind,
NULL,
NULL, /* get_gc */
};
/* by_ref is int due to Iterator API */
static zend_object_iterator *zend_weakmap_get_iterator(
zend_class_entry *ce, zval *object, int by_ref)
{
zend_weakmap *wm = zend_weakmap_fetch(object);
zend_weakmap_iterator *iter = emalloc(sizeof(zend_weakmap_iterator));
zend_iterator_init(&iter->it);
iter->it.funcs = &zend_weakmap_iterator_funcs;
ZVAL_COPY(&iter->it.data, object);
iter->ht_iter = zend_hash_iterator_add(&wm->ht, 0);
return &iter->it;
}
ZEND_METHOD(WeakMap, offsetGet)
{
zval *key;
if (zend_parse_parameters(ZEND_NUM_ARGS(), "z", &key) == FAILURE) {
return;
}
zval *zv = zend_weakmap_read_dimension(Z_OBJ_P(ZEND_THIS), key, BP_VAR_R, NULL);
if (!zv) {
return;
}
ZVAL_COPY(return_value, zv);
}
ZEND_METHOD(WeakMap, offsetSet)
{
zval *key, *value;
if (zend_parse_parameters(ZEND_NUM_ARGS(), "zz", &key, &value) == FAILURE) {
return;
}
zend_weakmap_write_dimension(Z_OBJ_P(ZEND_THIS), key, value);
}
ZEND_METHOD(WeakMap, offsetExists)
{
zval *key;
if (zend_parse_parameters(ZEND_NUM_ARGS(), "z", &key) == FAILURE) {
return;
}
RETURN_BOOL(zend_weakmap_has_dimension(Z_OBJ_P(ZEND_THIS), key, /* check_empty */ 0));
}
ZEND_METHOD(WeakMap, offsetUnset)
{
zval *key;
if (zend_parse_parameters(ZEND_NUM_ARGS(), "z", &key) == FAILURE) {
return;
}
zend_weakmap_unset_dimension(Z_OBJ_P(ZEND_THIS), key);
}
ZEND_METHOD(WeakMap, count)
{
if (zend_parse_parameters_none() == FAILURE) {
return;
}
zend_long count;
zend_weakmap_count_elements(Z_OBJ_P(ZEND_THIS), &count);
RETURN_LONG(count);
}
ZEND_METHOD(WeakMap, getIterator)
{
if (zend_parse_parameters_none() == FAILURE) {
return;
}
zend_create_internal_iterator_zval(return_value, ZEND_THIS);
}
void zend_register_weakref_ce(void) /* {{{ */
{
zend_ce_weakref = register_class_WeakReference();
zend_ce_weakref->create_object = zend_weakref_new;
zend_ce_weakref->serialize = zend_class_serialize_deny;
zend_ce_weakref->unserialize = zend_class_unserialize_deny;
memcpy(&zend_weakref_handlers, zend_get_std_object_handlers(), sizeof(zend_object_handlers));
zend_weakref_handlers.offset = XtOffsetOf(zend_weakref, std);
zend_weakref_handlers.free_obj = zend_weakref_free;
zend_weakref_handlers.clone_obj = NULL;
zend_ce_weakmap = register_class_WeakMap(zend_ce_arrayaccess, zend_ce_countable, zend_ce_aggregate);
zend_ce_weakmap->create_object = zend_weakmap_create_object;
zend_ce_weakmap->get_iterator = zend_weakmap_get_iterator;
zend_ce_weakmap->serialize = zend_class_serialize_deny;
zend_ce_weakmap->unserialize = zend_class_unserialize_deny;
memcpy(&zend_weakmap_handlers, zend_get_std_object_handlers(), sizeof(zend_object_handlers));
zend_weakmap_handlers.offset = XtOffsetOf(zend_weakmap, std);
zend_weakmap_handlers.free_obj = zend_weakmap_free_obj;
zend_weakmap_handlers.read_dimension = zend_weakmap_read_dimension;
zend_weakmap_handlers.write_dimension = zend_weakmap_write_dimension;
zend_weakmap_handlers.has_dimension = zend_weakmap_has_dimension;
zend_weakmap_handlers.unset_dimension = zend_weakmap_unset_dimension;
zend_weakmap_handlers.count_elements = zend_weakmap_count_elements;
zend_weakmap_handlers.get_properties_for = zend_weakmap_get_properties_for;
zend_weakmap_handlers.get_gc = zend_weakmap_get_gc;
zend_weakmap_handlers.clone_obj = zend_weakmap_clone_obj;
}
/* }}} */