Google Git
Sign in
chromium / v8 / v8.git / 3.13.5.2 / . / src / handles.cc
blob: adf435573e75e108c9706f0629200985409be087 [file] [log] [blame]
// Copyright 2012 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include "v8.h"
#include "accessors.h"
#include "api.h"
#include "arguments.h"
#include "bootstrapper.h"
#include "compiler.h"
#include "debug.h"
#include "execution.h"
#include "global-handles.h"
#include "natives.h"
#include "runtime.h"
#include "string-search.h"
#include "stub-cache.h"
#include "vm-state-inl.h"
namespace v8 {
namespace internal {
int HandleScope::NumberOfHandles() {
Isolate* isolate = Isolate::Current();
HandleScopeImplementer* impl = isolate->handle_scope_implementer();
int n = impl->blocks()->length();
if (n == 0) return 0;
return ((n - 1) * kHandleBlockSize) + static_cast<int>(
(isolate->handle_scope_data()->next - impl->blocks()->last()));
}
Object** HandleScope::Extend() {
Isolate* isolate = Isolate::Current();
v8::ImplementationUtilities::HandleScopeData* current =
isolate->handle_scope_data();
Object** result = current->next;
ASSERT(result == current->limit);
// Make sure there's at least one scope on the stack and that the
// top of the scope stack isn't a barrier.
if (current->level == 0) {
Utils::ReportApiFailure("v8::HandleScope::CreateHandle()",
"Cannot create a handle without a HandleScope");
return NULL;
}
HandleScopeImplementer* impl = isolate->handle_scope_implementer();
// If there's more room in the last block, we use that. This is used
// for fast creation of scopes after scope barriers.
if (!impl->blocks()->is_empty()) {
Object** limit = &impl->blocks()->last()[kHandleBlockSize];
if (current->limit != limit) {
current->limit = limit;
ASSERT(limit - current->next < kHandleBlockSize);
}
}
// If we still haven't found a slot for the handle, we extend the
// current handle scope by allocating a new handle block.
if (result == current->limit) {
// If there's a spare block, use it for growing the current scope.
result = impl->GetSpareOrNewBlock();
// Add the extension to the global list of blocks, but count the
// extension as part of the current scope.
impl->blocks()->Add(result);
current->limit = &result[kHandleBlockSize];
}
return result;
}
void HandleScope::DeleteExtensions(Isolate* isolate) {
ASSERT(isolate == Isolate::Current());
v8::ImplementationUtilities::HandleScopeData* current =
isolate->handle_scope_data();
isolate->handle_scope_implementer()->DeleteExtensions(current->limit);
}
void HandleScope::ZapRange(Object** start, Object** end) {
ASSERT(end - start <= kHandleBlockSize);
for (Object** p = start; p != end; p++) {
*reinterpret_cast<Address*>(p) = v8::internal::kHandleZapValue;
}
}
Address HandleScope::current_level_address() {
return reinterpret_cast<Address>(
&Isolate::Current()->handle_scope_data()->level);
}
Address HandleScope::current_next_address() {
return reinterpret_cast<Address>(
&Isolate::Current()->handle_scope_data()->next);
}
Address HandleScope::current_limit_address() {
return reinterpret_cast<Address>(
&Isolate::Current()->handle_scope_data()->limit);
}
Handle<FixedArray> AddKeysFromJSArray(Handle<FixedArray> content,
Handle<JSArray> array) {
CALL_HEAP_FUNCTION(content->GetIsolate(),
content->AddKeysFromJSArray(*array), FixedArray);
}
Handle<FixedArray> UnionOfKeys(Handle<FixedArray> first,
Handle<FixedArray> second) {
CALL_HEAP_FUNCTION(first->GetIsolate(),
first->UnionOfKeys(*second), FixedArray);
}
Handle<JSGlobalProxy> ReinitializeJSGlobalProxy(
Handle<JSFunction> constructor,
Handle<JSGlobalProxy> global) {
CALL_HEAP_FUNCTION(
constructor->GetIsolate(),
constructor->GetHeap()->ReinitializeJSGlobalProxy(*constructor, *global),
JSGlobalProxy);
}
void SetExpectedNofProperties(Handle<JSFunction> func, int nof) {
// If objects constructed from this function exist then changing
// 'estimated_nof_properties' is dangerous since the previous value might
// have been compiled into the fast construct stub. More over, the inobject
// slack tracking logic might have adjusted the previous value, so even
// passing the same value is risky.
if (func->shared()->live_objects_may_exist()) return;
func->shared()->set_expected_nof_properties(nof);
if (func->has_initial_map()) {
Handle<Map> new_initial_map =
func->GetIsolate()->factory()->CopyMap(
Handle<Map>(func->initial_map()));
new_initial_map->set_unused_property_fields(nof);
func->set_initial_map(*new_initial_map);
}
}
void SetPrototypeProperty(Handle<JSFunction> func, Handle<JSObject> value) {
CALL_HEAP_FUNCTION_VOID(func->GetIsolate(),
func->SetPrototype(*value));
}
static int ExpectedNofPropertiesFromEstimate(int estimate) {
// If no properties are added in the constructor, they are more likely
// to be added later.
if (estimate == 0) estimate = 2;
// We do not shrink objects that go into a snapshot (yet), so we adjust
// the estimate conservatively.
if (Serializer::enabled()) return estimate + 2;
// Inobject slack tracking will reclaim redundant inobject space later,
// so we can afford to adjust the estimate generously.
if (FLAG_clever_optimizations) {
return estimate + 8;
} else {
return estimate + 3;
}
}
void SetExpectedNofPropertiesFromEstimate(Handle<SharedFunctionInfo> shared,
int estimate) {
// See the comment in SetExpectedNofProperties.
if (shared->live_objects_may_exist()) return;
shared->set_expected_nof_properties(
ExpectedNofPropertiesFromEstimate(estimate));
}
void FlattenString(Handle<String> string) {
CALL_HEAP_FUNCTION_VOID(string->GetIsolate(), string->TryFlatten());
}
Handle<String> FlattenGetString(Handle<String> string) {
CALL_HEAP_FUNCTION(string->GetIsolate(), string->TryFlatten(), String);
}
Handle<Object> SetPrototype(Handle<JSFunction> function,
Handle<Object> prototype) {
ASSERT(function->should_have_prototype());
CALL_HEAP_FUNCTION(function->GetIsolate(),
Accessors::FunctionSetPrototype(*function,
*prototype,
NULL),
Object);
}
Handle<Object> SetProperty(Handle<Object> object,
Handle<Object> key,
Handle<Object> value,
PropertyAttributes attributes,
StrictModeFlag strict_mode) {
Isolate* isolate = Isolate::Current();
CALL_HEAP_FUNCTION(
isolate,
Runtime::SetObjectProperty(
isolate, object, key, value, attributes, strict_mode),
Object);
}
Handle<Object> ForceSetProperty(Handle<JSObject> object,
Handle<Object> key,
Handle<Object> value,
PropertyAttributes attributes) {
Isolate* isolate = object->GetIsolate();
CALL_HEAP_FUNCTION(
isolate,
Runtime::ForceSetObjectProperty(
isolate, object, key, value, attributes),
Object);
}
Handle<Object> ForceDeleteProperty(Handle<JSObject> object,
Handle<Object> key) {
Isolate* isolate = object->GetIsolate();
CALL_HEAP_FUNCTION(isolate,
Runtime::ForceDeleteObjectProperty(isolate, object, key),
Object);
}
Handle<Object> SetPropertyWithInterceptor(Handle<JSObject> object,
Handle<String> key,
Handle<Object> value,
PropertyAttributes attributes,
StrictModeFlag strict_mode) {
CALL_HEAP_FUNCTION(object->GetIsolate(),
object->SetPropertyWithInterceptor(*key,
*value,
attributes,
strict_mode),
Object);
}
Handle<Object> GetProperty(Handle<JSReceiver> obj,
const char* name) {
Isolate* isolate = obj->GetIsolate();
Handle<String> str = isolate->factory()->LookupAsciiSymbol(name);
CALL_HEAP_FUNCTION(isolate, obj->GetProperty(*str), Object);
}
Handle<Object> GetProperty(Handle<Object> obj,
Handle<Object> key) {
Isolate* isolate = Isolate::Current();
CALL_HEAP_FUNCTION(isolate,
Runtime::GetObjectProperty(isolate, obj, key), Object);
}
Handle<Object> GetPropertyWithInterceptor(Handle<JSObject> receiver,
Handle<JSObject> holder,
Handle<String> name,
PropertyAttributes* attributes) {
Isolate* isolate = receiver->GetIsolate();
CALL_HEAP_FUNCTION(isolate,
holder->GetPropertyWithInterceptor(*receiver,
*name,
attributes),
Object);
}
Handle<Object> SetPrototype(Handle<JSObject> obj, Handle<Object> value) {
const bool skip_hidden_prototypes = false;
CALL_HEAP_FUNCTION(obj->GetIsolate(),
obj->SetPrototype(*value, skip_hidden_prototypes), Object);
}
Handle<Object> LookupSingleCharacterStringFromCode(uint32_t index) {
Isolate* isolate = Isolate::Current();
CALL_HEAP_FUNCTION(
isolate,
isolate->heap()->LookupSingleCharacterStringFromCode(index), Object);
}
Handle<String> SubString(Handle<String> str,
int start,
int end,
PretenureFlag pretenure) {
CALL_HEAP_FUNCTION(str->GetIsolate(),
str->SubString(start, end, pretenure), String);
}
Handle<JSObject> Copy(Handle<JSObject> obj) {
Isolate* isolate = obj->GetIsolate();
CALL_HEAP_FUNCTION(isolate,
isolate->heap()->CopyJSObject(*obj), JSObject);
}
Handle<Object> SetAccessor(Handle<JSObject> obj, Handle<AccessorInfo> info) {
CALL_HEAP_FUNCTION(obj->GetIsolate(), obj->DefineAccessor(*info), Object);
}
// Wrappers for scripts are kept alive and cached in weak global
// handles referred from foreign objects held by the scripts as long as
// they are used. When they are not used anymore, the garbage
// collector will call the weak callback on the global handle
// associated with the wrapper and get rid of both the wrapper and the
// handle.
static void ClearWrapperCache(Persistent<v8::Value> handle, void*) {
Handle<Object> cache = Utils::OpenHandle(*handle);
JSValue* wrapper = JSValue::cast(*cache);
Foreign* foreign = Script::cast(wrapper->value())->wrapper();
ASSERT(foreign->foreign_address() ==
reinterpret_cast<Address>(cache.location()));
foreign->set_foreign_address(0);
Isolate* isolate = Isolate::Current();
isolate->global_handles()->Destroy(cache.location());
isolate->counters()->script_wrappers()->Decrement();
}
Handle<JSValue> GetScriptWrapper(Handle<Script> script) {
if (script->wrapper()->foreign_address() != NULL) {
// Return the script wrapper directly from the cache.
return Handle<JSValue>(
reinterpret_cast<JSValue**>(script->wrapper()->foreign_address()));
}
Isolate* isolate = Isolate::Current();
// Construct a new script wrapper.
isolate->counters()->script_wrappers()->Increment();
Handle<JSFunction> constructor = isolate->script_function();
Handle<JSValue> result =
Handle<JSValue>::cast(isolate->factory()->NewJSObject(constructor));
result->set_value(*script);
// Create a new weak global handle and use it to cache the wrapper
// for future use. The cache will automatically be cleared by the
// garbage collector when it is not used anymore.
Handle<Object> handle = isolate->global_handles()->Create(*result);
isolate->global_handles()->MakeWeak(handle.location(), NULL,
&ClearWrapperCache);
script->wrapper()->set_foreign_address(
reinterpret_cast<Address>(handle.location()));
return result;
}
// Init line_ends array with code positions of line ends inside script
// source.
void InitScriptLineEnds(Handle<Script> script) {
if (!script->line_ends()->IsUndefined()) return;
Isolate* isolate = script->GetIsolate();
if (!script->source()->IsString()) {
ASSERT(script->source()->IsUndefined());
Handle<FixedArray> empty = isolate->factory()->NewFixedArray(0);
script->set_line_ends(*empty);
ASSERT(script->line_ends()->IsFixedArray());
return;
}
Handle<String> src(String::cast(script->source()), isolate);
Handle<FixedArray> array = CalculateLineEnds(src, true);
if (*array != isolate->heap()->empty_fixed_array()) {
array->set_map(isolate->heap()->fixed_cow_array_map());
}
script->set_line_ends(*array);
ASSERT(script->line_ends()->IsFixedArray());
}
template <typename SourceChar>
static void CalculateLineEnds(Isolate* isolate,
List<int>* line_ends,
Vector<const SourceChar> src,
bool with_last_line) {
const int src_len = src.length();
StringSearch<char, SourceChar> search(isolate, CStrVector("\n"));
// Find and record line ends.
int position = 0;
while (position != -1 && position < src_len) {
position = search.Search(src, position);
if (position != -1) {
line_ends->Add(position);
position++;
} else if (with_last_line) {
// Even if the last line misses a line end, it is counted.
line_ends->Add(src_len);
return;
}
}
}
Handle<FixedArray> CalculateLineEnds(Handle<String> src,
bool with_last_line) {
src = FlattenGetString(src);
// Rough estimate of line count based on a roughly estimated average
// length of (unpacked) code.
int line_count_estimate = src->length() >> 4;
List<int> line_ends(line_count_estimate);
Isolate* isolate = src->GetIsolate();
{
AssertNoAllocation no_heap_allocation; // ensure vectors stay valid.
// Dispatch on type of strings.
String::FlatContent content = src->GetFlatContent();
ASSERT(content.IsFlat());
if (content.IsAscii()) {
CalculateLineEnds(isolate,
&line_ends,
content.ToAsciiVector(),
with_last_line);
} else {
CalculateLineEnds(isolate,
&line_ends,
content.ToUC16Vector(),
with_last_line);
}
}
int line_count = line_ends.length();
Handle<FixedArray> array = isolate->factory()->NewFixedArray(line_count);
for (int i = 0; i < line_count; i++) {
array->set(i, Smi::FromInt(line_ends[i]));
}
return array;
}
// Convert code position into line number.
int GetScriptLineNumber(Handle<Script> script, int code_pos) {
InitScriptLineEnds(script);
AssertNoAllocation no_allocation;
FixedArray* line_ends_array = FixedArray::cast(script->line_ends());
const int line_ends_len = line_ends_array->length();
if (!line_ends_len) return -1;
if ((Smi::cast(line_ends_array->get(0)))->value() >= code_pos) {
return script->line_offset()->value();
}
int left = 0;
int right = line_ends_len;
while (int half = (right - left) / 2) {
if ((Smi::cast(line_ends_array->get(left + half)))->value() > code_pos) {
right -= half;
} else {
left += half;
}
}
return right + script->line_offset()->value();
}
// Convert code position into column number.
int GetScriptColumnNumber(Handle<Script> script, int code_pos) {
int line_number = GetScriptLineNumber(script, code_pos);
if (line_number == -1) return -1;
AssertNoAllocation no_allocation;
FixedArray* line_ends_array = FixedArray::cast(script->line_ends());
line_number = line_number - script->line_offset()->value();
if (line_number == 0) return code_pos + script->column_offset()->value();
int prev_line_end_pos =
Smi::cast(line_ends_array->get(line_number - 1))->value();
return code_pos - (prev_line_end_pos + 1);
}
int GetScriptLineNumberSafe(Handle<Script> script, int code_pos) {
AssertNoAllocation no_allocation;
if (!script->line_ends()->IsUndefined()) {
return GetScriptLineNumber(script, code_pos);
}
// Slow mode: we do not have line_ends. We have to iterate through source.
if (!script->source()->IsString()) {
return -1;
}
String* source = String::cast(script->source());
int line = 0;
int len = source->length();
for (int pos = 0; pos < len; pos++) {
if (pos == code_pos) {
break;
}
if (source->Get(pos) == '\n') {
line++;
}
}
return line;
}
void CustomArguments::IterateInstance(ObjectVisitor* v) {
v->VisitPointers(values_, values_ + ARRAY_SIZE(values_));
}
// Compute the property keys from the interceptor.
v8::Handle<v8::Array> GetKeysForNamedInterceptor(Handle<JSReceiver> receiver,
Handle<JSObject> object) {
Isolate* isolate = receiver->GetIsolate();
Handle<InterceptorInfo> interceptor(object->GetNamedInterceptor());
CustomArguments args(isolate, interceptor->data(), *receiver, *object);
v8::AccessorInfo info(args.end());
v8::Handle<v8::Array> result;
if (!interceptor->enumerator()->IsUndefined()) {
v8::NamedPropertyEnumerator enum_fun =
v8::ToCData<v8::NamedPropertyEnumerator>(interceptor->enumerator());
LOG(isolate, ApiObjectAccess("interceptor-named-enum", *object));
{
// Leaving JavaScript.
VMState state(isolate, EXTERNAL);
result = enum_fun(info);
}
}
return result;
}
// Compute the element keys from the interceptor.
v8::Handle<v8::Array> GetKeysForIndexedInterceptor(Handle<JSReceiver> receiver,
Handle<JSObject> object) {
Isolate* isolate = receiver->GetIsolate();
Handle<InterceptorInfo> interceptor(object->GetIndexedInterceptor());
CustomArguments args(isolate, interceptor->data(), *receiver, *object);
v8::AccessorInfo info(args.end());
v8::Handle<v8::Array> result;
if (!interceptor->enumerator()->IsUndefined()) {
v8::IndexedPropertyEnumerator enum_fun =
v8::ToCData<v8::IndexedPropertyEnumerator>(interceptor->enumerator());
LOG(isolate, ApiObjectAccess("interceptor-indexed-enum", *object));
{
// Leaving JavaScript.
VMState state(isolate, EXTERNAL);
result = enum_fun(info);
}
}
return result;
}
static bool ContainsOnlyValidKeys(Handle<FixedArray> array) {
int len = array->length();
for (int i = 0; i < len; i++) {
Object* e = array->get(i);
if (!(e->IsString() || e->IsNumber())) return false;
}
return true;
}
Handle<FixedArray> GetKeysInFixedArrayFor(Handle<JSReceiver> object,
KeyCollectionType type,
bool* threw) {
USE(ContainsOnlyValidKeys);
Isolate* isolate = object->GetIsolate();
Handle<FixedArray> content = isolate->factory()->empty_fixed_array();
Handle<JSObject> arguments_boilerplate = Handle<JSObject>(
isolate->context()->native_context()->arguments_boilerplate(),
isolate);
Handle<JSFunction> arguments_function = Handle<JSFunction>(
JSFunction::cast(arguments_boilerplate->map()->constructor()),
isolate);
// Only collect keys if access is permitted.
for (Handle<Object> p = object;
*p != isolate->heap()->null_value();
p = Handle<Object>(p->GetPrototype(), isolate)) {
if (p->IsJSProxy()) {
Handle<JSProxy> proxy(JSProxy::cast(*p), isolate);
Handle<Object> args[] = { proxy };
Handle<Object> names = Execution::Call(
isolate->proxy_enumerate(), object, ARRAY_SIZE(args), args, threw);
if (*threw) return content;
content = AddKeysFromJSArray(content, Handle<JSArray>::cast(names));
break;
}
Handle<JSObject> current(JSObject::cast(*p), isolate);
// Check access rights if required.
if (current->IsAccessCheckNeeded() &&
!isolate->MayNamedAccess(*current,
isolate->heap()->undefined_value(),
v8::ACCESS_KEYS)) {
isolate->ReportFailedAccessCheck(*current, v8::ACCESS_KEYS);
break;
}
// Compute the element keys.
Handle<FixedArray> element_keys =
isolate->factory()->NewFixedArray(current->NumberOfEnumElements());
current->GetEnumElementKeys(*element_keys);
content = UnionOfKeys(content, element_keys);
ASSERT(ContainsOnlyValidKeys(content));
// Add the element keys from the interceptor.
if (current->HasIndexedInterceptor()) {
v8::Handle<v8::Array> result =
GetKeysForIndexedInterceptor(object, current);
if (!result.IsEmpty())
content = AddKeysFromJSArray(content, v8::Utils::OpenHandle(*result));
ASSERT(ContainsOnlyValidKeys(content));
}
// We can cache the computed property keys if access checks are
// not needed and no interceptors are involved.
//
// We do not use the cache if the object has elements and
// therefore it does not make sense to cache the property names
// for arguments objects. Arguments objects will always have
// elements.
// Wrapped strings have elements, but don't have an elements
// array or dictionary. So the fast inline test for whether to
// use the cache says yes, so we should not create a cache.
bool cache_enum_keys =
((current->map()->constructor() != *arguments_function) &&
!current->IsJSValue() &&
!current->IsAccessCheckNeeded() &&
!current->HasNamedInterceptor() &&
!current->HasIndexedInterceptor());
// Compute the property keys and cache them if possible.
content =
UnionOfKeys(content, GetEnumPropertyKeys(current, cache_enum_keys));
ASSERT(ContainsOnlyValidKeys(content));
// Add the property keys from the interceptor.
if (current->HasNamedInterceptor()) {
v8::Handle<v8::Array> result =
GetKeysForNamedInterceptor(object, current);
if (!result.IsEmpty())
content = AddKeysFromJSArray(content, v8::Utils::OpenHandle(*result));
ASSERT(ContainsOnlyValidKeys(content));
}
// If we only want local properties we bail out after the first
// iteration.
if (type == LOCAL_ONLY)
break;
}
return content;
}
Handle<JSArray> GetKeysFor(Handle<JSReceiver> object, bool* threw) {
Isolate* isolate = object->GetIsolate();
isolate->counters()->for_in()->Increment();
Handle<FixedArray> elements =
GetKeysInFixedArrayFor(object, INCLUDE_PROTOS, threw);
return isolate->factory()->NewJSArrayWithElements(elements);
}
Handle<FixedArray> GetEnumPropertyKeys(Handle<JSObject> object,
bool cache_result) {
Isolate* isolate = object->GetIsolate();
if (object->HasFastProperties()) {
if (object->map()->instance_descriptors()->HasEnumCache()) {
int own_property_count = object->map()->EnumLength();
// Mark that we have an enum cache if we are allowed to cache it.
if (cache_result && own_property_count == Map::kInvalidEnumCache) {
int num_enum = object->map()->NumberOfDescribedProperties(DONT_ENUM);
object->map()->SetEnumLength(num_enum);
}
DescriptorArray* desc = object->map()->instance_descriptors();
Handle<FixedArray> keys(FixedArray::cast(desc->GetEnumCache()), isolate);
isolate->counters()->enum_cache_hits()->Increment();
return keys;
}
Handle<Map> map(object->map());
if (map->instance_descriptors()->IsEmpty()) {
isolate->counters()->enum_cache_hits()->Increment();
if (cache_result) map->SetEnumLength(0);
return isolate->factory()->empty_fixed_array();
}
isolate->counters()->enum_cache_misses()->Increment();
int num_enum = map->NumberOfDescribedProperties(DONT_ENUM);
Handle<FixedArray> storage = isolate->factory()->NewFixedArray(num_enum);
Handle<FixedArray> indices = isolate->factory()->NewFixedArray(num_enum);
Handle<DescriptorArray> descs =
Handle<DescriptorArray>(object->map()->instance_descriptors(), isolate);
int index = 0;
for (int i = 0; i < descs->number_of_descriptors(); i++) {
PropertyDetails details = descs->GetDetails(i);
if (!details.IsDontEnum()) {
storage->set(index, descs->GetKey(i));
if (!indices.is_null()) {
if (details.type() != FIELD) {
indices = Handle<FixedArray>();
} else {
int field_index = Descriptor::IndexFromValue(descs->GetValue(i));
if (field_index >= map->inobject_properties()) {
field_index = -(field_index - map->inobject_properties() + 1);
}
indices->set(index, Smi::FromInt(field_index));
}
}
index++;
}
}
ASSERT(index == storage->length());
Handle<FixedArray> bridge_storage =
isolate->factory()->NewFixedArray(
DescriptorArray::kEnumCacheBridgeLength);
DescriptorArray* desc = object->map()->instance_descriptors();
desc->SetEnumCache(*bridge_storage,
*storage,
indices.is_null() ? Object::cast(Smi::FromInt(0))
: Object::cast(*indices));
if (cache_result) {
object->map()->SetEnumLength(index);
}
return storage;
} else {
int num_enum = object->NumberOfLocalProperties(DONT_ENUM);
Handle<FixedArray> storage = isolate->factory()->NewFixedArray(num_enum);
Handle<FixedArray> sort_array = isolate->factory()->NewFixedArray(num_enum);
object->property_dictionary()->CopyEnumKeysTo(*storage, *sort_array);
return storage;
}
}
Handle<ObjectHashSet> ObjectHashSetAdd(Handle<ObjectHashSet> table,
Handle<Object> key) {
CALL_HEAP_FUNCTION(table->GetIsolate(),
table->Add(*key),
ObjectHashSet);
}
Handle<ObjectHashSet> ObjectHashSetRemove(Handle<ObjectHashSet> table,
Handle<Object> key) {
CALL_HEAP_FUNCTION(table->GetIsolate(),
table->Remove(*key),
ObjectHashSet);
}
Handle<ObjectHashTable> PutIntoObjectHashTable(Handle<ObjectHashTable> table,
Handle<Object> key,
Handle<Object> value) {
CALL_HEAP_FUNCTION(table->GetIsolate(),
table->Put(*key, *value),
ObjectHashTable);
}
// This method determines the type of string involved and then gets the UTF8
// length of the string. It doesn't flatten the string and has log(n) recursion
// for a string of length n. If the failure flag gets set, then we have to
// flatten the string and retry. Failures are caused by surrogate pairs in deep
// cons strings.
// Single surrogate characters that are encountered in the UTF-16 character
// sequence of the input string get counted as 3 UTF-8 bytes, because that
// is the way that WriteUtf8 will encode them. Surrogate pairs are counted and
// encoded as one 4-byte UTF-8 sequence.
// This function conceptually uses recursion on the two halves of cons strings.
// However, in order to avoid the recursion going too deep it recurses on the
// second string of the cons, but iterates on the first substring (by manually
// eliminating it as a tail recursion). This means it counts the UTF-8 length
// from the end to the start, which makes no difference to the total.
// Surrogate pairs are recognized even if they are split across two sides of a
// cons, which complicates the implementation somewhat. Therefore, too deep
// recursion cannot always be avoided. This case is detected, and the failure
// flag is set, a signal to the caller that the string should be flattened and
// the operation retried.
int Utf8LengthHelper(String* input,
int from,
int to,
bool followed_by_surrogate,
int max_recursion,
bool* failure,
bool* starts_with_surrogate) {
if (from == to) return 0;
int total = 0;
bool dummy;
while (true) {
if (input->IsAsciiRepresentation()) {
*starts_with_surrogate = false;
return total + to - from;
}
switch (StringShape(input).representation_tag()) {
case kConsStringTag: {
ConsString* str = ConsString::cast(input);
String* first = str->first();
String* second = str->second();
int first_length = first->length();
if (first_length - from > to - first_length) {
if (first_length < to) {
// Right hand side is shorter. No need to check the recursion depth
// since this can only happen log(n) times.
bool right_starts_with_surrogate = false;
total += Utf8LengthHelper(second,
0,
to - first_length,
followed_by_surrogate,
max_recursion - 1,
failure,
&right_starts_with_surrogate);
if (*failure) return 0;
followed_by_surrogate = right_starts_with_surrogate;
input = first;
to = first_length;
} else {
// We only need the left hand side.
input = first;
}
} else {
if (first_length > from) {
// Left hand side is shorter.
if (first->IsAsciiRepresentation()) {
total += first_length - from;
*starts_with_surrogate = false;
starts_with_surrogate = &dummy;
input = second;
from = 0;
to -= first_length;
} else if (second->IsAsciiRepresentation()) {
followed_by_surrogate = false;
total += to - first_length;
input = first;
to = first_length;
} else if (max_recursion > 0) {
bool right_starts_with_surrogate = false;
// Recursing on the long one. This may fail.
total += Utf8LengthHelper(second,
0,
to - first_length,
followed_by_surrogate,
max_recursion - 1,
failure,
&right_starts_with_surrogate);
if (*failure) return 0;
input = first;
to = first_length;
followed_by_surrogate = right_starts_with_surrogate;
} else {
*failure = true;
return 0;
}
} else {
// We only need the right hand side.
input = second;
from = 0;
to -= first_length;
}
}
continue;
}
case kExternalStringTag:
case kSeqStringTag: {
Vector<const uc16> vector = input->GetFlatContent().ToUC16Vector();
const uc16* p = vector.start();
int previous = unibrow::Utf16::kNoPreviousCharacter;
for (int i = from; i < to; i++) {
uc16 c = p[i];
total += unibrow::Utf8::Length(c, previous);
previous = c;
}
if (to - from > 0) {
if (unibrow::Utf16::IsLeadSurrogate(previous) &&
followed_by_surrogate) {
total -= unibrow::Utf8::kBytesSavedByCombiningSurrogates;
}
if (unibrow::Utf16::IsTrailSurrogate(p[from])) {
*starts_with_surrogate = true;
}
}
return total;
}
case kSlicedStringTag: {
SlicedString* str = SlicedString::cast(input);
int offset = str->offset();
input = str->parent();
from += offset;
to += offset;
continue;
}
default:
break;
}
UNREACHABLE();
return 0;
}
return 0;
}
int Utf8Length(Handle<String> str) {
bool dummy;
bool failure;
int len;
const int kRecursionBudget = 100;
do {
failure = false;
len = Utf8LengthHelper(
*str, 0, str->length(), false, kRecursionBudget, &failure, &dummy);
if (failure) FlattenString(str);
} while (failure);
return len;
}
DeferredHandleScope::DeferredHandleScope(Isolate* isolate)
: impl_(isolate->handle_scope_implementer()) {
ASSERT(impl_->isolate() == Isolate::Current());
impl_->BeginDeferredScope();
v8::ImplementationUtilities::HandleScopeData* data =
impl_->isolate()->handle_scope_data();
Object** new_next = impl_->GetSpareOrNewBlock();
Object** new_limit = &new_next[kHandleBlockSize];
ASSERT(data->limit == &impl_->blocks()->last()[kHandleBlockSize]);
impl_->blocks()->Add(new_next);
#ifdef DEBUG
prev_level_ = data->level;
#endif
data->level++;
prev_limit_ = data->limit;
prev_next_ = data->next;
data->next = new_next;
data->limit = new_limit;
}
DeferredHandleScope::~DeferredHandleScope() {
impl_->isolate()->handle_scope_data()->level--;
ASSERT(handles_detached_);
ASSERT(impl_->isolate()->handle_scope_data()->level == prev_level_);
}
DeferredHandles* DeferredHandleScope::Detach() {
DeferredHandles* deferred = impl_->Detach(prev_limit_);
v8::ImplementationUtilities::HandleScopeData* data =
impl_->isolate()->handle_scope_data();
data->next = prev_next_;
data->limit = prev_limit_;
#ifdef DEBUG
handles_detached_ = true;
#endif
return deferred;
}
} } // namespace v8::internal