v8::internal::ArrayConcatVisitor Class Reference

A simple visitor visits every element of Array's. More...

Collaboration diagram for v8::internal::ArrayConcatVisitor:

Public Member Functions
	ArrayConcatVisitor (Isolate *isolate, Handle< FixedArray > storage, bool fast_elements)
	~ArrayConcatVisitor ()
void	visit (uint32_t i, Handle< Object > elm)
void	increase_index_offset (uint32_t delta)
bool	exceeds_array_limit ()
Handle< JSArray >	ToArray ()

Private Member Functions
void	SetDictionaryMode ()
void	clear_storage ()
void	set_storage (FixedArray *storage)

Private Attributes
Isolate *	isolate_
Handle< FixedArray >	storage_
uint32_t	index_offset_
bool	fast_elements_: 1
bool	exceeds_array_limit_: 1

Detailed Description

A simple visitor visits every element of Array's.

The backend storage can be a fixed array for fast elements case, or a dictionary for sparse array. Since Dictionary is a subtype of FixedArray, the class can be used by both fast and slow cases. The second parameter of the constructor, fast_elements, specifies whether the storage is a FixedArray or Dictionary.

An index limit is used to deal with the situation that a result array length overflows 32-bit non-negative integer.

Definition at line 4605 of file runtime.cc.

Constructor & Destructor Documentation

ArrayConcatVisitor()

v8::internal::ArrayConcatVisitor::ArrayConcatVisitor ( Isolate *  isolate, Handle< FixedArray >  storage, bool  fast_elements  )

inline

Definition at line 4607 of file runtime.cc.

      : isolate_(isolate),
        storage_(Handle<FixedArray>::cast(
            isolate->global_handles()->Create(*storage))),
        index_offset_(0u),
        fast_elements_(fast_elements),
        exceeds_array_limit_(false) {}

~ArrayConcatVisitor()

v8::internal::ArrayConcatVisitor::~ArrayConcatVisitor ( )

inline

Definition at line 4616 of file runtime.cc.

{ clear_storage(); }

References clear_storage().

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Member Function Documentation

clear_storage()

void v8::internal::ArrayConcatVisitor::clear_storage ( )

inlineprivate

Definition at line 4703 of file runtime.cc.

                              {
    GlobalHandles::Destroy(Handle<Object>::cast(storage_).location());
  }

References v8::internal::GlobalHandles::Destroy(), and storage_.

Referenced by SetDictionaryMode(), visit(), and ~ArrayConcatVisitor().

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exceeds_array_limit()

bool v8::internal::ArrayConcatVisitor::exceeds_array_limit ( )

inline

Definition at line 4665 of file runtime.cc.

{ return exceeds_array_limit_; }

References exceeds_array_limit_.

Referenced by v8::internal::RUNTIME_FUNCTION().

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increase_index_offset()

void v8::internal::ArrayConcatVisitor::increase_index_offset ( uint32_t  delta )

inline

Definition at line 4649 of file runtime.cc.

                                             {
    if (JSObject::kMaxElementCount - index_offset_ < delta) {
      index_offset_ = JSObject::kMaxElementCount;
    } else {
      index_offset_ += delta;
    }
    // If the initial length estimate was off (see special case in visit()),
    // but the array blowing the limit didn't contain elements beyond the
    // provided-for index range, go to dictionary mode now.
    if (fast_elements_ &&
        index_offset_ >
            static_cast<uint32_t>(FixedArrayBase::cast(*storage_)->length())) {
      SetDictionaryMode();
    }
  }

References fast_elements_, index_offset_, v8::internal::JSObject::kMaxElementCount, and SetDictionaryMode().

Referenced by v8::internal::IterateElements(), and v8::internal::RUNTIME_FUNCTION().

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set_storage()

void v8::internal::ArrayConcatVisitor::set_storage ( FixedArray *  storage )

inlineprivate

Definition at line 4707 of file runtime.cc.

                                               {
    storage_ =
        Handle<FixedArray>::cast(isolate_->global_handles()->Create(storage));
  }

References v8::internal::Handle< T >::cast(), v8::internal::GlobalHandles::Create(), v8::internal::Isolate::global_handles(), isolate_, and storage_.

Referenced by SetDictionaryMode(), and visit().

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SetDictionaryMode()

void v8::internal::ArrayConcatVisitor::SetDictionaryMode ( )

inlineprivate

Definition at line 4681 of file runtime.cc.

                           {
    DCHECK(fast_elements_);
    Handle<FixedArray> current_storage(*storage_);
    Handle<SeededNumberDictionary> slow_storage(
        SeededNumberDictionary::New(isolate_, current_storage->length()));
    uint32_t current_length = static_cast<uint32_t>(current_storage->length());
    for (uint32_t i = 0; i < current_length; i++) {
      HandleScope loop_scope(isolate_);
      Handle<Object> element(current_storage->get(i), isolate_);
      if (!element->IsTheHole()) {
        Handle<SeededNumberDictionary> new_storage =
            SeededNumberDictionary::AtNumberPut(slow_storage, i, element);
        if (!new_storage.is_identical_to(slow_storage)) {
          slow_storage = loop_scope.CloseAndEscape(new_storage);
        }
      }
    }
    clear_storage();
    set_storage(*slow_storage);
    fast_elements_ = false;
  }

References v8::internal::SeededNumberDictionary::AtNumberPut(), clear_storage(), v8::internal::HandleScope::CloseAndEscape(), DCHECK, fast_elements_, isolate_, v8::internal::Dictionary< SeededNumberDictionary, SeededNumberDictionaryShape, uint32_t >::New(), set_storage(), and storage_.

Referenced by increase_index_offset(), and visit().

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ToArray()

Handle<JSArray> v8::internal::ArrayConcatVisitor::ToArray ( )

inline

Definition at line 4667 of file runtime.cc.

                            {
    Handle<JSArray> array = isolate_->factory()->NewJSArray(0);
    Handle<Object> length =
        isolate_->factory()->NewNumber(static_cast<double>(index_offset_));
    Handle<Map> map = JSObject::GetElementsTransitionMap(
        array, fast_elements_ ? FAST_HOLEY_ELEMENTS : DICTIONARY_ELEMENTS);
    array->set_map(*map);
    array->set_length(*length);
    array->set_elements(*storage_);
    return array;
  }

References v8::internal::DICTIONARY_ELEMENTS, v8::internal::Isolate::factory(), fast_elements_, v8::internal::FAST_HOLEY_ELEMENTS, v8::internal::JSObject::GetElementsTransitionMap(), index_offset_, isolate_, map, and storage_.

Referenced by v8::internal::RUNTIME_FUNCTION().

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visit()

void v8::internal::ArrayConcatVisitor::visit ( uint32_t  i, Handle< Object >  elm  )

inline

Definition at line 4618 of file runtime.cc.

                                             {
    if (i > JSObject::kMaxElementCount - index_offset_) {
      exceeds_array_limit_ = true;
      return;
    }
    uint32_t index = index_offset_ + i;
 
    if (fast_elements_) {
      if (index < static_cast<uint32_t>(storage_->length())) {
        storage_->set(index, *elm);
        return;
      }
      // Our initial estimate of length was foiled, possibly by
      // getters on the arrays increasing the length of later arrays
      // during iteration.
      // This shouldn't happen in anything but pathological cases.
      SetDictionaryMode();
      // Fall-through to dictionary mode.
    }
    DCHECK(!fast_elements_);
    Handle<SeededNumberDictionary> dict(
        SeededNumberDictionary::cast(*storage_));
    Handle<SeededNumberDictionary> result =
        SeededNumberDictionary::AtNumberPut(dict, index, elm);
    if (!result.is_identical_to(dict)) {
      // Dictionary needed to grow.
      clear_storage();
      set_storage(*result);
    }
  }

References v8::internal::SeededNumberDictionary::AtNumberPut(), clear_storage(), DCHECK, exceeds_array_limit_, fast_elements_, index_offset_, v8::internal::JSObject::kMaxElementCount, set_storage(), SetDictionaryMode(), and storage_.

Referenced by v8::internal::IterateElements(), v8::internal::IterateExternalArrayElements(), and v8::internal::RUNTIME_FUNCTION().

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Member Data Documentation

exceeds_array_limit_

bool v8::internal::ArrayConcatVisitor::exceeds_array_limit_

private

Definition at line 4718 of file runtime.cc.

Referenced by exceeds_array_limit(), and visit().

fast_elements_

bool v8::internal::ArrayConcatVisitor::fast_elements_

private

Definition at line 4717 of file runtime.cc.

Referenced by increase_index_offset(), SetDictionaryMode(), ToArray(), and visit().

index_offset_

uint32_t v8::internal::ArrayConcatVisitor::index_offset_

private

Definition at line 4716 of file runtime.cc.

Referenced by increase_index_offset(), ToArray(), and visit().

isolate_

Isolate* v8::internal::ArrayConcatVisitor::isolate_

private

Definition at line 4712 of file runtime.cc.

Referenced by set_storage(), SetDictionaryMode(), and ToArray().

storage_

Handle<FixedArray> v8::internal::ArrayConcatVisitor::storage_

private

Definition at line 4713 of file runtime.cc.

Referenced by clear_storage(), set_storage(), SetDictionaryMode(), ToArray(), and visit().

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The documentation for this class was generated from the following file:

• /mnt/V8SourceCode/src/runtime/runtime.cc