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keys.cc
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// Copyright 2013 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "src/objects/keys.h"
#include "src/api/api-arguments-inl.h"
#include "src/common/globals.h"
#include "src/execution/isolate-inl.h"
#include "src/handles/handles-inl.h"
#include "src/heap/factory.h"
#include "src/objects/api-callbacks.h"
#include "src/objects/elements-inl.h"
#include "src/objects/field-index-inl.h"
#include "src/objects/hash-table-inl.h"
#include "src/objects/module-inl.h"
#include "src/objects/objects-inl.h"
#include "src/objects/ordered-hash-table-inl.h"
#include "src/objects/property-descriptor.h"
#include "src/objects/prototype.h"
#include "src/objects/slots-atomic-inl.h"
#include "src/utils/identity-map.h"
#include "src/zone/zone-hashmap.h"
namespace v8 {
namespace internal {
#define RETURN_NOTHING_IF_NOT_SUCCESSFUL(call) \
do { \
if (!(call)) return Nothing<bool>(); \
} while (false)
#define RETURN_FAILURE_IF_NOT_SUCCESSFUL(call) \
do { \
ExceptionStatus status_enum_result = (call); \
if (!status_enum_result) return status_enum_result; \
} while (false)
namespace {
static bool ContainsOnlyValidKeys(Handle<FixedArray> array) {
int len = array->length();
for (int i = 0; i < len; i++) {
Object e = array->get(i);
if (!(e.IsName() || e.IsNumber())) return false;
}
return true;
}
static int AddKey(Object key, Handle<FixedArray> combined_keys,
Handle<DescriptorArray> descs, int nof_descriptors,
int target) {
for (InternalIndex i : InternalIndex::Range(nof_descriptors)) {
if (descs->GetKey(i) == key) return 0;
}
combined_keys->set(target, key);
return 1;
}
static Handle<FixedArray> CombineKeys(Isolate* isolate,
Handle<FixedArray> own_keys,
Handle<FixedArray> prototype_chain_keys,
Handle<JSReceiver> receiver,
bool may_have_elements) {
int prototype_chain_keys_length = prototype_chain_keys->length();
if (prototype_chain_keys_length == 0) return own_keys;
Map map = receiver->map();
int nof_descriptors = map.NumberOfOwnDescriptors();
if (nof_descriptors == 0 && !may_have_elements) return prototype_chain_keys;
Handle<DescriptorArray> descs(map.instance_descriptors(isolate), isolate);
int own_keys_length = own_keys.is_null() ? 0 : own_keys->length();
Handle<FixedArray> combined_keys = isolate->factory()->NewFixedArray(
own_keys_length + prototype_chain_keys_length);
if (own_keys_length != 0) {
own_keys->CopyTo(0, *combined_keys, 0, own_keys_length);
}
int target_keys_length = own_keys_length;
for (int i = 0; i < prototype_chain_keys_length; i++) {
target_keys_length += AddKey(prototype_chain_keys->get(i), combined_keys,
descs, nof_descriptors, target_keys_length);
}
return FixedArray::ShrinkOrEmpty(isolate, combined_keys, target_keys_length);
}
} // namespace
// static
MaybeHandle<FixedArray> KeyAccumulator::GetKeys(
Handle<JSReceiver> object, KeyCollectionMode mode, PropertyFilter filter,
GetKeysConversion keys_conversion, bool is_for_in, bool skip_indices) {
Isolate* isolate = object->GetIsolate();
FastKeyAccumulator accumulator(isolate, object, mode, filter, is_for_in,
skip_indices);
return accumulator.GetKeys(keys_conversion);
}
Handle<FixedArray> KeyAccumulator::GetKeys(GetKeysConversion convert) {
if (keys_.is_null()) {
return isolate_->factory()->empty_fixed_array();
}
USE(ContainsOnlyValidKeys);
Handle<FixedArray> result =
OrderedHashSet::ConvertToKeysArray(isolate(), keys(), convert);
DCHECK(ContainsOnlyValidKeys(result));
if (try_prototype_info_cache_ && !first_prototype_map_.is_null()) {
PrototypeInfo::cast(first_prototype_map_->prototype_info())
.set_prototype_chain_enum_cache(*result);
Map::GetOrCreatePrototypeChainValidityCell(
Handle<Map>(receiver_->map(), isolate_), isolate_);
DCHECK(first_prototype_map_->IsPrototypeValidityCellValid());
}
return result;
}
Handle<OrderedHashSet> KeyAccumulator::keys() {
return Handle<OrderedHashSet>::cast(keys_);
}
ExceptionStatus KeyAccumulator::AddKey(Object key, AddKeyConversion convert) {
return AddKey(handle(key, isolate_), convert);
}
ExceptionStatus KeyAccumulator::AddKey(Handle<Object> key,
AddKeyConversion convert) {
if (filter_ == PRIVATE_NAMES_ONLY) {
if (!key->IsSymbol()) return ExceptionStatus::kSuccess;
if (!Symbol::cast(*key).is_private_name()) return ExceptionStatus::kSuccess;
} else if (key->IsSymbol()) {
if (filter_ & SKIP_SYMBOLS) return ExceptionStatus::kSuccess;
if (Symbol::cast(*key).is_private()) return ExceptionStatus::kSuccess;
} else if (filter_ & SKIP_STRINGS) {
return ExceptionStatus::kSuccess;
}
if (IsShadowed(key)) return ExceptionStatus::kSuccess;
if (keys_.is_null()) {
keys_ = OrderedHashSet::Allocate(isolate_, 16).ToHandleChecked();
}
uint32_t index;
if (convert == CONVERT_TO_ARRAY_INDEX && key->IsString() &&
Handle<String>::cast(key)->AsArrayIndex(&index)) {
key = isolate_->factory()->NewNumberFromUint(index);
}
MaybeHandle<OrderedHashSet> new_set_candidate =
OrderedHashSet::Add(isolate(), keys(), key);
Handle<OrderedHashSet> new_set;
if (!new_set_candidate.ToHandle(&new_set)) {
THROW_NEW_ERROR_RETURN_VALUE(
isolate_, NewRangeError(MessageTemplate::kTooManyProperties),
ExceptionStatus::kException);
}
if (*new_set != *keys_) {
// The keys_ Set is converted directly to a FixedArray in GetKeys which can
// be left-trimmer. Hence the previous Set should not keep a pointer to the
// new one.
keys_->set(OrderedHashSet::NextTableIndex(), Smi::zero());
keys_ = new_set;
}
return ExceptionStatus::kSuccess;
}
ExceptionStatus KeyAccumulator::AddKeys(Handle<FixedArray> array,
AddKeyConversion convert) {
int add_length = array->length();
for (int i = 0; i < add_length; i++) {
Handle<Object> current(array->get(i), isolate_);
RETURN_FAILURE_IF_NOT_SUCCESSFUL(AddKey(current, convert));
}
return ExceptionStatus::kSuccess;
}
ExceptionStatus KeyAccumulator::AddKeys(Handle<JSObject> array_like,
AddKeyConversion convert) {
DCHECK(array_like->IsJSArray() || array_like->HasSloppyArgumentsElements());
ElementsAccessor* accessor = array_like->GetElementsAccessor();
return accessor->AddElementsToKeyAccumulator(array_like, this, convert);
}
MaybeHandle<FixedArray> FilterProxyKeys(KeyAccumulator* accumulator,
Handle<JSProxy> owner,
Handle<FixedArray> keys,
PropertyFilter filter) {
if (filter == ALL_PROPERTIES) {
// Nothing to do.
return keys;
}
Isolate* isolate = accumulator->isolate();
int store_position = 0;
for (int i = 0; i < keys->length(); ++i) {
Handle<Name> key(Name::cast(keys->get(i)), isolate);
if (key->FilterKey(filter)) continue; // Skip this key.
if (filter & ONLY_ENUMERABLE) {
PropertyDescriptor desc;
Maybe<bool> found =
JSProxy::GetOwnPropertyDescriptor(isolate, owner, key, &desc);
MAYBE_RETURN(found, MaybeHandle<FixedArray>());
if (!found.FromJust()) continue;
if (!desc.enumerable()) {
accumulator->AddShadowingKey(key);
continue;
}
}
// Keep this key.
if (store_position != i) {
keys->set(store_position, *key);
}
store_position++;
}
return FixedArray::ShrinkOrEmpty(isolate, keys, store_position);
}
// Returns "nothing" in case of exception, "true" on success.
Maybe<bool> KeyAccumulator::AddKeysFromJSProxy(Handle<JSProxy> proxy,
Handle<FixedArray> keys) {
// Postpone the enumerable check for for-in to the ForInFilter step.
if (!is_for_in_) {
ASSIGN_RETURN_ON_EXCEPTION_VALUE(
isolate_, keys, FilterProxyKeys(this, proxy, keys, filter_),
Nothing<bool>());
}
// https://tc39.es/ecma262/#sec-proxy-object-internal-methods-and-internal-slots-ownpropertykeys
// As of 10.5.11.9 says, the keys collected from Proxy should not contain
// any duplicates. And the order of the keys is preserved by the
// OrderedHashTable.
RETURN_NOTHING_IF_NOT_SUCCESSFUL(AddKeys(keys, CONVERT_TO_ARRAY_INDEX));
return Just(true);
}
Maybe<bool> KeyAccumulator::CollectKeys(Handle<JSReceiver> receiver,
Handle<JSReceiver> object) {
// Proxies have no hidden prototype and we should not trigger the
// [[GetPrototypeOf]] trap on the last iteration when using
// AdvanceFollowingProxies.
if (mode_ == KeyCollectionMode::kOwnOnly && object->IsJSProxy()) {
MAYBE_RETURN(CollectOwnJSProxyKeys(receiver, Handle<JSProxy>::cast(object)),
Nothing<bool>());
return Just(true);
}
PrototypeIterator::WhereToEnd end = mode_ == KeyCollectionMode::kOwnOnly
? PrototypeIterator::END_AT_NON_HIDDEN
: PrototypeIterator::END_AT_NULL;
for (PrototypeIterator iter(isolate_, object, kStartAtReceiver, end);
!iter.IsAtEnd();) {
// Start the shadow checks only after the first prototype has added
// shadowing keys.
if (HasShadowingKeys()) skip_shadow_check_ = false;
Handle<JSReceiver> current =
PrototypeIterator::GetCurrent<JSReceiver>(iter);
Maybe<bool> result = Just(false); // Dummy initialization.
if (current->IsJSProxy()) {
result = CollectOwnJSProxyKeys(receiver, Handle<JSProxy>::cast(current));
} else {
DCHECK(current->IsJSObject());
result = CollectOwnKeys(receiver, Handle<JSObject>::cast(current));
}
MAYBE_RETURN(result, Nothing<bool>());
if (!result.FromJust()) break; // |false| means "stop iterating".
// Iterate through proxies but ignore access checks for the ALL_CAN_READ
// case on API objects for OWN_ONLY keys handled in CollectOwnKeys.
if (!iter.AdvanceFollowingProxiesIgnoringAccessChecks()) {
return Nothing<bool>();
}
if (!last_non_empty_prototype_.is_null() &&
*last_non_empty_prototype_ == *current) {
break;
}
}
return Just(true);
}
bool KeyAccumulator::HasShadowingKeys() { return !shadowing_keys_.is_null(); }
bool KeyAccumulator::IsShadowed(Handle<Object> key) {
if (!HasShadowingKeys() || skip_shadow_check_) return false;
return shadowing_keys_->Has(isolate_, key);
}
void KeyAccumulator::AddShadowingKey(Object key,
AllowGarbageCollection* allow_gc) {
if (mode_ == KeyCollectionMode::kOwnOnly) return;
AddShadowingKey(handle(key, isolate_));
}
void KeyAccumulator::AddShadowingKey(Handle<Object> key) {
if (mode_ == KeyCollectionMode::kOwnOnly) return;
if (shadowing_keys_.is_null()) {
shadowing_keys_ = ObjectHashSet::New(isolate_, 16);
}
shadowing_keys_ = ObjectHashSet::Add(isolate(), shadowing_keys_, key);
}
namespace {
void TrySettingEmptyEnumCache(JSReceiver object) {
Map map = object.map();
DCHECK_EQ(kInvalidEnumCacheSentinel, map.EnumLength());
if (!map.OnlyHasSimpleProperties()) return;
if (map.IsJSProxyMap()) return;
if (map.NumberOfEnumerableProperties() > 0) return;
DCHECK(object.IsJSObject());
map.SetEnumLength(0);
}
bool CheckAndInitalizeEmptyEnumCache(JSReceiver object) {
if (object.map().EnumLength() == kInvalidEnumCacheSentinel) {
TrySettingEmptyEnumCache(object);
}
if (object.map().EnumLength() != 0) return false;
DCHECK(object.IsJSObject());
return !JSObject::cast(object).HasEnumerableElements();
}
} // namespace
void FastKeyAccumulator::Prepare() {
DisallowGarbageCollection no_gc;
// Directly go for the fast path for OWN_ONLY keys.
if (mode_ == KeyCollectionMode::kOwnOnly) return;
// Fully walk the prototype chain and find the last prototype with keys.
is_receiver_simple_enum_ = false;
has_empty_prototype_ = true;
only_own_has_simple_elements_ =
!receiver_->map().IsCustomElementsReceiverMap();
JSReceiver last_prototype;
may_have_elements_ = MayHaveElements(*receiver_);
for (PrototypeIterator iter(isolate_, *receiver_); !iter.IsAtEnd();
iter.Advance()) {
JSReceiver current = iter.GetCurrent<JSReceiver>();
if (!may_have_elements_ || only_own_has_simple_elements_) {
if (MayHaveElements(current)) {
may_have_elements_ = true;
only_own_has_simple_elements_ = false;
}
}
bool has_no_properties = CheckAndInitalizeEmptyEnumCache(current);
if (has_no_properties) continue;
last_prototype = current;
has_empty_prototype_ = false;
}
// Check if we should try to create/use prototype info cache.
try_prototype_info_cache_ = TryPrototypeInfoCache(receiver_);
if (has_prototype_info_cache_) return;
if (has_empty_prototype_) {
is_receiver_simple_enum_ =
receiver_->map().EnumLength() != kInvalidEnumCacheSentinel &&
!JSObject::cast(*receiver_).HasEnumerableElements();
} else if (!last_prototype.is_null()) {
last_non_empty_prototype_ = handle(last_prototype, isolate_);
}
}
namespace {
Handle<FixedArray> ReduceFixedArrayTo(Isolate* isolate,
Handle<FixedArray> array, int length) {
DCHECK_LE(length, array->length());
if (array->length() == length) return array;
return isolate->factory()->CopyFixedArrayUpTo(array, length);
}
// Initializes and directly returns the enume cache. Users of this function
// have to make sure to never directly leak the enum cache.
Handle<FixedArray> GetFastEnumPropertyKeys(Isolate* isolate,
Handle<JSObject> object) {
Handle<Map> map(object->map(), isolate);
Handle<FixedArray> keys(
map->instance_descriptors(isolate).enum_cache().keys(), isolate);
// Check if the {map} has a valid enum length, which implies that it
// must have a valid enum cache as well.
int enum_length = map->EnumLength();
if (enum_length != kInvalidEnumCacheSentinel) {
DCHECK(map->OnlyHasSimpleProperties());
DCHECK_LE(enum_length, keys->length());
DCHECK_EQ(enum_length, map->NumberOfEnumerableProperties());
isolate->counters()->enum_cache_hits()->Increment();
return ReduceFixedArrayTo(isolate, keys, enum_length);
}
// Determine the actual number of enumerable properties of the {map}.
enum_length = map->NumberOfEnumerableProperties();
// Check if there's already a shared enum cache on the {map}s
// DescriptorArray with sufficient number of entries.
if (enum_length <= keys->length()) {
if (map->OnlyHasSimpleProperties()) map->SetEnumLength(enum_length);
isolate->counters()->enum_cache_hits()->Increment();
return ReduceFixedArrayTo(isolate, keys, enum_length);
}
Handle<DescriptorArray> descriptors =
Handle<DescriptorArray>(map->instance_descriptors(isolate), isolate);
isolate->counters()->enum_cache_misses()->Increment();
// Create the keys array.
int index = 0;
bool fields_only = true;
keys = isolate->factory()->NewFixedArray(enum_length);
for (InternalIndex i : map->IterateOwnDescriptors()) {
DisallowGarbageCollection no_gc;
PropertyDetails details = descriptors->GetDetails(i);
if (details.IsDontEnum()) continue;
Object key = descriptors->GetKey(i);
if (key.IsSymbol()) continue;
keys->set(index, key);
if (details.location() != PropertyLocation::kField) fields_only = false;
index++;
}
DCHECK_EQ(index, keys->length());
// Optionally also create the indices array.
Handle<FixedArray> indices = isolate->factory()->empty_fixed_array();
if (fields_only) {
indices = isolate->factory()->NewFixedArray(enum_length);
index = 0;
for (InternalIndex i : map->IterateOwnDescriptors()) {
DisallowGarbageCollection no_gc;
PropertyDetails details = descriptors->GetDetails(i);
if (details.IsDontEnum()) continue;
Object key = descriptors->GetKey(i);
if (key.IsSymbol()) continue;
DCHECK_EQ(PropertyKind::kData, details.kind());
DCHECK_EQ(PropertyLocation::kField, details.location());
FieldIndex field_index = FieldIndex::ForDescriptor(*map, i);
indices->set(index, Smi::FromInt(field_index.GetLoadByFieldIndex()));
index++;
}
DCHECK_EQ(index, indices->length());
}
DescriptorArray::InitializeOrChangeEnumCache(descriptors, isolate, keys,
indices);
if (map->OnlyHasSimpleProperties()) map->SetEnumLength(enum_length);
return keys;
}
template <bool fast_properties>
MaybeHandle<FixedArray> GetOwnKeysWithElements(Isolate* isolate,
Handle<JSObject> object,
GetKeysConversion convert,
bool skip_indices) {
Handle<FixedArray> keys;
ElementsAccessor* accessor = object->GetElementsAccessor();
if (fast_properties) {
keys = GetFastEnumPropertyKeys(isolate, object);
} else {
// TODO(cbruni): preallocate big enough array to also hold elements.
keys = KeyAccumulator::GetOwnEnumPropertyKeys(isolate, object);
}
MaybeHandle<FixedArray> result;
if (skip_indices) {
result = keys;
} else {
result =
accessor->PrependElementIndices(object, keys, convert, ONLY_ENUMERABLE);
}
if (FLAG_trace_for_in_enumerate) {
PrintF("| strings=%d symbols=0 elements=%u || prototypes>=1 ||\n",
keys->length(), result.ToHandleChecked()->length() - keys->length());
}
return result;
}
} // namespace
MaybeHandle<FixedArray> FastKeyAccumulator::GetKeys(
GetKeysConversion keys_conversion) {
// TODO(v8:9401): We should extend the fast path of KeyAccumulator::GetKeys to
// also use fast path even when filter = SKIP_SYMBOLS. We used to pass wrong
// filter to use fast path in cases where we tried to verify all properties
// are enumerable. However these checks weren't correct and passing the wrong
// filter led to wrong behaviour.
if (filter_ == ENUMERABLE_STRINGS) {
Handle<FixedArray> keys;
if (GetKeysFast(keys_conversion).ToHandle(&keys)) {
return keys;
}
if (isolate_->has_pending_exception()) return MaybeHandle<FixedArray>();
}
if (try_prototype_info_cache_) {
return GetKeysWithPrototypeInfoCache(keys_conversion);
}
return GetKeysSlow(keys_conversion);
}
MaybeHandle<FixedArray> FastKeyAccumulator::GetKeysFast(
GetKeysConversion keys_conversion) {
bool own_only = has_empty_prototype_ || mode_ == KeyCollectionMode::kOwnOnly;
Map map = receiver_->map();
if (!own_only || map.IsCustomElementsReceiverMap()) {
return MaybeHandle<FixedArray>();
}
// From this point on we are certain to only collect own keys.
DCHECK(receiver_->IsJSObject());
Handle<JSObject> object = Handle<JSObject>::cast(receiver_);
// Do not try to use the enum-cache for dict-mode objects.
if (map.is_dictionary_map()) {
return GetOwnKeysWithElements<false>(isolate_, object, keys_conversion,
skip_indices_);
}
int enum_length = receiver_->map().EnumLength();
if (enum_length == kInvalidEnumCacheSentinel) {
Handle<FixedArray> keys;
// Try initializing the enum cache and return own properties.
if (GetOwnKeysWithUninitializedEnumCache().ToHandle(&keys)) {
if (FLAG_trace_for_in_enumerate) {
PrintF("| strings=%d symbols=0 elements=0 || prototypes>=1 ||\n",
keys->length());
}
is_receiver_simple_enum_ =
object->map().EnumLength() != kInvalidEnumCacheSentinel;
return keys;
}
}
// The properties-only case failed because there were probably elements on the
// receiver.
return GetOwnKeysWithElements<true>(isolate_, object, keys_conversion,
skip_indices_);
}
MaybeHandle<FixedArray>
FastKeyAccumulator::GetOwnKeysWithUninitializedEnumCache() {
Handle<JSObject> object = Handle<JSObject>::cast(receiver_);
// Uninitalized enum cache
Map map = object->map();
if (object->elements() != ReadOnlyRoots(isolate_).empty_fixed_array() &&
object->elements() !=
ReadOnlyRoots(isolate_).empty_slow_element_dictionary()) {
// Assume that there are elements.
return MaybeHandle<FixedArray>();
}
int number_of_own_descriptors = map.NumberOfOwnDescriptors();
if (number_of_own_descriptors == 0) {
map.SetEnumLength(0);
return isolate_->factory()->empty_fixed_array();
}
// We have no elements but possibly enumerable property keys, hence we can
// directly initialize the enum cache.
Handle<FixedArray> keys = GetFastEnumPropertyKeys(isolate_, object);
if (is_for_in_) return keys;
// Do not leak the enum cache as it might end up as an elements backing store.
return isolate_->factory()->CopyFixedArray(keys);
}
MaybeHandle<FixedArray> FastKeyAccumulator::GetKeysSlow(
GetKeysConversion keys_conversion) {
KeyAccumulator accumulator(isolate_, mode_, filter_);
accumulator.set_is_for_in(is_for_in_);
accumulator.set_skip_indices(skip_indices_);
accumulator.set_last_non_empty_prototype(last_non_empty_prototype_);
accumulator.set_may_have_elements(may_have_elements_);
accumulator.set_first_prototype_map(first_prototype_map_);
accumulator.set_try_prototype_info_cache(try_prototype_info_cache_);
MAYBE_RETURN(accumulator.CollectKeys(receiver_, receiver_),
MaybeHandle<FixedArray>());
return accumulator.GetKeys(keys_conversion);
}
MaybeHandle<FixedArray> FastKeyAccumulator::GetKeysWithPrototypeInfoCache(
GetKeysConversion keys_conversion) {
Handle<FixedArray> own_keys;
if (may_have_elements_) {
MaybeHandle<FixedArray> maybe_own_keys;
if (receiver_->map().is_dictionary_map()) {
maybe_own_keys = GetOwnKeysWithElements<false>(
isolate_, Handle<JSObject>::cast(receiver_), keys_conversion,
skip_indices_);
} else {
maybe_own_keys = GetOwnKeysWithElements<true>(
isolate_, Handle<JSObject>::cast(receiver_), keys_conversion,
skip_indices_);
}
ASSIGN_RETURN_ON_EXCEPTION(isolate_, own_keys, maybe_own_keys, FixedArray);
} else {
own_keys = KeyAccumulator::GetOwnEnumPropertyKeys(
isolate_, Handle<JSObject>::cast(receiver_));
}
Handle<FixedArray> prototype_chain_keys;
if (has_prototype_info_cache_) {
prototype_chain_keys =
handle(FixedArray::cast(
PrototypeInfo::cast(first_prototype_map_->prototype_info())
.prototype_chain_enum_cache()),
isolate_);
} else {
KeyAccumulator accumulator(isolate_, mode_, filter_);
accumulator.set_is_for_in(is_for_in_);
accumulator.set_skip_indices(skip_indices_);
accumulator.set_last_non_empty_prototype(last_non_empty_prototype_);
accumulator.set_may_have_elements(may_have_elements_);
accumulator.set_receiver(receiver_);
accumulator.set_first_prototype_map(first_prototype_map_);
accumulator.set_try_prototype_info_cache(try_prototype_info_cache_);
MAYBE_RETURN(accumulator.CollectKeys(first_prototype_, first_prototype_),
MaybeHandle<FixedArray>());
prototype_chain_keys = accumulator.GetKeys(keys_conversion);
}
Handle<FixedArray> result = CombineKeys(
isolate_, own_keys, prototype_chain_keys, receiver_, may_have_elements_);
if (is_for_in_ && own_keys.is_identical_to(result)) {
// Don't leak the enumeration cache without the receiver since it might get
// trimmed otherwise.
return isolate_->factory()->CopyFixedArrayUpTo(result, result->length());
}
return result;
}
bool FastKeyAccumulator::MayHaveElements(JSReceiver receiver) {
if (!receiver.IsJSObject()) return true;
JSObject object = JSObject::cast(receiver);
if (object.HasEnumerableElements()) return true;
if (object.HasIndexedInterceptor()) return true;
return false;
}
bool FastKeyAccumulator::TryPrototypeInfoCache(Handle<JSReceiver> receiver) {
if (may_have_elements_ && !only_own_has_simple_elements_) return false;
Handle<JSObject> object = Handle<JSObject>::cast(receiver);
if (!object->HasFastProperties()) return false;
if (object->HasNamedInterceptor()) return false;
if (object->IsAccessCheckNeeded() &&
!isolate_->MayAccess(handle(isolate_->context(), isolate_), object)) {
return false;
}
HeapObject prototype = receiver->map().prototype();
if (prototype.is_null()) return false;
if (!prototype.map().is_prototype_map() ||
!prototype.map().prototype_info().IsPrototypeInfo()) {
return false;
}
first_prototype_ = handle(JSReceiver::cast(prototype), isolate_);
Handle<Map> map(prototype.map(), isolate_);
first_prototype_map_ = map;
has_prototype_info_cache_ = map->IsPrototypeValidityCellValid() &&
PrototypeInfo::cast(map->prototype_info())
.prototype_chain_enum_cache()
.IsFixedArray();
return true;
}
V8_WARN_UNUSED_RESULT ExceptionStatus
KeyAccumulator::FilterForEnumerableProperties(
Handle<JSReceiver> receiver, Handle<JSObject> object,
Handle<InterceptorInfo> interceptor, Handle<JSObject> result,
IndexedOrNamed type) {
DCHECK(result->IsJSArray() || result->HasSloppyArgumentsElements());
ElementsAccessor* accessor = result->GetElementsAccessor();
size_t length = accessor->GetCapacity(*result, result->elements());
for (InternalIndex entry : InternalIndex::Range(length)) {
if (!accessor->HasEntry(*result, entry)) continue;
// args are invalid after args.Call(), create a new one in every iteration.
PropertyCallbackArguments args(isolate_, interceptor->data(), *receiver,
*object, Just(kDontThrow));
Handle<Object> element = accessor->Get(result, entry);
Handle<Object> attributes;
if (type == kIndexed) {
uint32_t number;
CHECK(element->ToUint32(&number));
attributes = args.CallIndexedQuery(interceptor, number);
} else {
CHECK(element->IsName());
attributes =
args.CallNamedQuery(interceptor, Handle<Name>::cast(element));
}
if (!attributes.is_null()) {
int32_t value;
CHECK(attributes->ToInt32(&value));
if ((value & DONT_ENUM) == 0) {
RETURN_FAILURE_IF_NOT_SUCCESSFUL(AddKey(element, DO_NOT_CONVERT));
}
}
}
return ExceptionStatus::kSuccess;
}
// Returns |true| on success, |nothing| on exception.
Maybe<bool> KeyAccumulator::CollectInterceptorKeysInternal(
Handle<JSReceiver> receiver, Handle<JSObject> object,
Handle<InterceptorInfo> interceptor, IndexedOrNamed type) {
PropertyCallbackArguments enum_args(isolate_, interceptor->data(), *receiver,
*object, Just(kDontThrow));
Handle<JSObject> result;
if (!interceptor->enumerator().IsUndefined(isolate_)) {
if (type == kIndexed) {
result = enum_args.CallIndexedEnumerator(interceptor);
} else {
DCHECK_EQ(type, kNamed);
result = enum_args.CallNamedEnumerator(interceptor);
}
}
RETURN_VALUE_IF_SCHEDULED_EXCEPTION(isolate_, Nothing<bool>());
if (result.is_null()) return Just(true);
if ((filter_ & ONLY_ENUMERABLE) &&
!interceptor->query().IsUndefined(isolate_)) {
RETURN_NOTHING_IF_NOT_SUCCESSFUL(FilterForEnumerableProperties(
receiver, object, interceptor, result, type));
} else {
RETURN_NOTHING_IF_NOT_SUCCESSFUL(AddKeys(
result, type == kIndexed ? CONVERT_TO_ARRAY_INDEX : DO_NOT_CONVERT));
}
return Just(true);
}
Maybe<bool> KeyAccumulator::CollectInterceptorKeys(Handle<JSReceiver> receiver,
Handle<JSObject> object,
IndexedOrNamed type) {
if (type == kIndexed) {
if (!object->HasIndexedInterceptor()) return Just(true);
} else {
if (!object->HasNamedInterceptor()) return Just(true);
}
Handle<InterceptorInfo> interceptor(type == kIndexed
? object->GetIndexedInterceptor()
: object->GetNamedInterceptor(),
isolate_);
if ((filter() & ONLY_ALL_CAN_READ) && !interceptor->all_can_read()) {
return Just(true);
}
return CollectInterceptorKeysInternal(receiver, object, interceptor, type);
}
Maybe<bool> KeyAccumulator::CollectOwnElementIndices(
Handle<JSReceiver> receiver, Handle<JSObject> object) {
if (filter_ & SKIP_STRINGS || skip_indices_) return Just(true);
ElementsAccessor* accessor = object->GetElementsAccessor();
RETURN_NOTHING_IF_NOT_SUCCESSFUL(
accessor->CollectElementIndices(object, this));
return CollectInterceptorKeys(receiver, object, kIndexed);
}
namespace {
template <bool skip_symbols>
base::Optional<int> CollectOwnPropertyNamesInternal(
Handle<JSObject> object, KeyAccumulator* keys,
Handle<DescriptorArray> descs, int start_index, int limit) {
AllowGarbageCollection allow_gc;
int first_skipped = -1;
PropertyFilter filter = keys->filter();
KeyCollectionMode mode = keys->mode();
for (InternalIndex i : InternalIndex::Range(start_index, limit)) {
bool is_shadowing_key = false;
PropertyDetails details = descs->GetDetails(i);
if ((details.attributes() & filter) != 0) {
if (mode == KeyCollectionMode::kIncludePrototypes) {
is_shadowing_key = true;
} else {
continue;
}
}
if (filter & ONLY_ALL_CAN_READ) {
if (details.kind() != PropertyKind::kAccessor) continue;
Object accessors = descs->GetStrongValue(i);
if (!accessors.IsAccessorInfo()) continue;
if (!AccessorInfo::cast(accessors).all_can_read()) continue;
}
Name key = descs->GetKey(i);
if (skip_symbols == key.IsSymbol()) {
if (first_skipped == -1) first_skipped = i.as_int();
continue;
}
if (key.FilterKey(keys->filter())) continue;
if (is_shadowing_key) {
// This might allocate, but {key} is not used afterwards.
keys->AddShadowingKey(key, &allow_gc);
continue;
} else {
if (keys->AddKey(key, DO_NOT_CONVERT) != ExceptionStatus::kSuccess) {
return base::Optional<int>();
}
}
}
return first_skipped;
}
// Logic shared between different specializations of CopyEnumKeysTo.
template <typename Dictionary>
void CommonCopyEnumKeysTo(Isolate* isolate, Handle<Dictionary> dictionary,
Handle<FixedArray> storage, KeyCollectionMode mode,
KeyAccumulator* accumulator) {
DCHECK_IMPLIES(mode != KeyCollectionMode::kOwnOnly, accumulator != nullptr);
int length = storage->length();
int properties = 0;
ReadOnlyRoots roots(isolate);
AllowGarbageCollection allow_gc;
for (InternalIndex i : dictionary->IterateEntries()) {
Object key;
if (!dictionary->ToKey(roots, i, &key)) continue;
bool is_shadowing_key = false;
if (key.IsSymbol()) continue;
PropertyDetails details = dictionary->DetailsAt(i);
if (details.IsDontEnum()) {
if (mode == KeyCollectionMode::kIncludePrototypes) {
is_shadowing_key = true;
} else {
continue;
}
}
if (is_shadowing_key) {
// This might allocate, but {key} is not used afterwards.
accumulator->AddShadowingKey(key, &allow_gc);
continue;
} else {
if (Dictionary::kIsOrderedDictionaryType) {
storage->set(properties, Name::cast(key));
} else {
// If the dictionary does not store elements in enumeration order,
// we need to sort it afterwards in CopyEnumKeysTo. To enable this we
// need to store indices at this point, rather than the values at the
// given indices.
storage->set(properties, Smi::FromInt(i.as_int()));
}
}
properties++;
if (mode == KeyCollectionMode::kOwnOnly && properties == length) break;
}
CHECK_EQ(length, properties);
}
// Copies enumerable keys to preallocated fixed array.
// Does not throw for uninitialized exports in module namespace objects, so
// this has to be checked separately.
template <typename Dictionary>
void CopyEnumKeysTo(Isolate* isolate, Handle<Dictionary> dictionary,
Handle<FixedArray> storage, KeyCollectionMode mode,
KeyAccumulator* accumulator) {
STATIC_ASSERT(!Dictionary::kIsOrderedDictionaryType);
CommonCopyEnumKeysTo<Dictionary>(isolate, dictionary, storage, mode,
accumulator);
int length = storage->length();
DisallowGarbageCollection no_gc;
Dictionary raw_dictionary = *dictionary;
FixedArray raw_storage = *storage;
EnumIndexComparator<Dictionary> cmp(raw_dictionary);
// Use AtomicSlot wrapper to ensure that std::sort uses atomic load and
// store operations that are safe for concurrent marking.
AtomicSlot start(storage->GetFirstElementAddress());
std::sort(start, start + length, cmp);
for (int i = 0; i < length; i++) {
InternalIndex index(Smi::ToInt(raw_storage.get(i)));
raw_storage.set(i, raw_dictionary.NameAt(index));
}
}
template <>
void CopyEnumKeysTo(Isolate* isolate, Handle<SwissNameDictionary> dictionary,
Handle<FixedArray> storage, KeyCollectionMode mode,
KeyAccumulator* accumulator) {
CommonCopyEnumKeysTo<SwissNameDictionary>(isolate, dictionary, storage, mode,
accumulator);
// No need to sort, as CommonCopyEnumKeysTo on OrderedNameDictionary
// adds entries to |storage| in the dict's insertion order
// Further, the template argument true above means that |storage|
// now contains the actual values from |dictionary|, rather than indices.
}
template <class T>
Handle<FixedArray> GetOwnEnumPropertyDictionaryKeys(Isolate* isolate,
KeyCollectionMode mode,
KeyAccumulator* accumulator,
Handle<JSObject> object,
T raw_dictionary) {
Handle<T> dictionary(raw_dictionary, isolate);
if (dictionary->NumberOfElements() == 0) {
return isolate->factory()->empty_fixed_array();
}
int length = dictionary->NumberOfEnumerableProperties();
Handle<FixedArray> storage = isolate->factory()->NewFixedArray(length);
CopyEnumKeysTo(isolate, dictionary, storage, mode, accumulator);
return storage;
}
// Collect the keys from |dictionary| into |keys|, in ascending chronological
// order of property creation.
template <typename Dictionary>
ExceptionStatus CollectKeysFromDictionary(Handle<Dictionary> dictionary,
KeyAccumulator* keys) {
Isolate* isolate = keys->isolate();
ReadOnlyRoots roots(isolate);
// TODO(jkummerow): Consider using a std::unique_ptr<InternalIndex[]> instead.
Handle<FixedArray> array =
isolate->factory()->NewFixedArray(dictionary->NumberOfElements());
int array_size = 0;
PropertyFilter filter = keys->filter();
// Handle enumerable strings in CopyEnumKeysTo.
DCHECK_NE(keys->filter(), ENUMERABLE_STRINGS);
{
DisallowGarbageCollection no_gc;
for (InternalIndex i : dictionary->IterateEntries()) {
Object key;
Dictionary raw_dictionary = *dictionary;
if (!raw_dictionary.ToKey(roots, i, &key)) continue;
if (key.FilterKey(filter)) continue;
PropertyDetails details = raw_dictionary.DetailsAt(i);
if ((details.attributes() & filter) != 0) {
AllowGarbageCollection gc;
// This might allocate, but {key} is not used afterwards.
keys->AddShadowingKey(key, &gc);
continue;
}
if (filter & ONLY_ALL_CAN_READ) {
if (details.kind() != PropertyKind::kAccessor) continue;
Object accessors = raw_dictionary.ValueAt(i);
if (!accessors.IsAccessorInfo()) continue;
if (!AccessorInfo::cast(accessors).all_can_read()) continue;
}
// TODO(emrich): consider storing keys instead of indices into the array
// in case of ordered dictionary type.
array->set(array_size++, Smi::FromInt(i.as_int()));
}
if (!Dictionary::kIsOrderedDictionaryType) {
// Sorting only needed if it's an unordered dictionary,
// otherwise we traversed elements in insertion order
EnumIndexComparator<Dictionary> cmp(*dictionary);
// Use AtomicSlot wrapper to ensure that std::sort uses atomic load and
// store operations that are safe for concurrent marking.
AtomicSlot start(array->GetFirstElementAddress());
std::sort(start, start + array_size, cmp);
}
}
bool has_seen_symbol = false;
for (int i = 0; i < array_size; i++) {
InternalIndex index(Smi::ToInt(array->get(i)));
Object key = dictionary->NameAt(index);
if (key.IsSymbol()) {
has_seen_symbol = true;
continue;
}
ExceptionStatus status = keys->AddKey(key, DO_NOT_CONVERT);
if (!status) return status;
}
if (has_seen_symbol) {
for (int i = 0; i < array_size; i++) {
InternalIndex index(Smi::ToInt(array->get(i)));
Object key = dictionary->NameAt(index);
if (!key.IsSymbol()) continue;
ExceptionStatus status = keys->AddKey(key, DO_NOT_CONVERT);
if (!status) return status;
}
}
return ExceptionStatus::kSuccess;
}
} // namespace
Maybe<bool> KeyAccumulator::CollectOwnPropertyNames(Handle<JSReceiver> receiver,
Handle<JSObject> object) {
if (filter_ == ENUMERABLE_STRINGS) {
Handle<FixedArray> enum_keys;
if (object->HasFastProperties()) {
enum_keys = KeyAccumulator::GetOwnEnumPropertyKeys(isolate_, object);
// If the number of properties equals the length of enumerable properties
// we do not have to filter out non-enumerable ones
Map map = object->map();
int nof_descriptors = map.NumberOfOwnDescriptors();
if (enum_keys->length() != nof_descriptors) {
if (map.prototype(isolate_) != ReadOnlyRoots(isolate_).null_value()) {
AllowGarbageCollection allow_gc;
Handle<DescriptorArray> descs = Handle<DescriptorArray>(
map.instance_descriptors(isolate_), isolate_);
for (InternalIndex i : InternalIndex::Range(nof_descriptors)) {
PropertyDetails details = descs->GetDetails(i);
if (!details.IsDontEnum()) continue;
this->AddShadowingKey(descs->GetKey(i), &allow_gc);
}
}
}
} else if (object->IsJSGlobalObject()) {
enum_keys = GetOwnEnumPropertyDictionaryKeys(
isolate_, mode_, this, object,
JSGlobalObject::cast(*object).global_dictionary(kAcquireLoad));
} else if (V8_ENABLE_SWISS_NAME_DICTIONARY_BOOL) {