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v8/src/value-serializer.cc
jbroman 5fa2734d39 ValueSerializer: Expose reading/writing doubles to embedder. 
BUG=chromium:148757

Review-Url: https://codereview.chromium.org/2386233002
Cr-Commit-Position: refs/heads/master@{#39955}
2016-10-04 13:44:41 +00:00

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// Copyright 2016 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/value-serializer.h"
#include <type_traits>
#include "src/base/logging.h"
#include "src/conversions.h"
#include "src/factory.h"
#include "src/handles-inl.h"
#include "src/isolate.h"
#include "src/objects-inl.h"
#include "src/objects.h"
#include "src/transitions.h"
namespace v8 {
namespace internal {
static const uint32_t kLatestVersion = 9;
static const int kPretenureThreshold = 100 * KB;
template <typename T>
static size_t BytesNeededForVarint(T value) {
static_assert(std::is_integral<T>::value && std::is_unsigned<T>::value,
"Only unsigned integer types can be written as varints.");
size_t result = 0;
do {
result++;
value >>= 7;
} while (value);
return result;
}
enum class SerializationTag : uint8_t {
// version:uint32_t (if at beginning of data, sets version > 0)
kVersion = 0xFF,
// ignore
kPadding = '\0',
// refTableSize:uint32_t (previously used for sanity checks; safe to ignore)
kVerifyObjectCount = '?',
// Oddballs (no data).
kUndefined = '_',
kNull = '0',
kTrue = 'T',
kFalse = 'F',
// Number represented as 32-bit integer, ZigZag-encoded
// (like sint32 in protobuf)
kInt32 = 'I',
// Number represented as 32-bit unsigned integer, varint-encoded
// (like uint32 in protobuf)
kUint32 = 'U',
// Number represented as a 64-bit double.
// Host byte order is used (N.B. this makes the format non-portable).
kDouble = 'N',
// byteLength:uint32_t, then raw data
kUtf8String = 'S',
kTwoByteString = 'c',
// Reference to a serialized object. objectID:uint32_t
kObjectReference = '^',
// Beginning of a JS object.
kBeginJSObject = 'o',
// End of a JS object. numProperties:uint32_t
kEndJSObject = '{',
// Beginning of a sparse JS array. length:uint32_t
// Elements and properties are written as key/value pairs, like objects.
kBeginSparseJSArray = 'a',
// End of a sparse JS array. numProperties:uint32_t length:uint32_t
kEndSparseJSArray = '@',
// Beginning of a dense JS array. length:uint32_t
// |length| elements, followed by properties as key/value pairs
kBeginDenseJSArray = 'A',
// End of a dense JS array. numProperties:uint32_t length:uint32_t
kEndDenseJSArray = '$',
// Date. millisSinceEpoch:double
kDate = 'D',
// Boolean object. No data.
kTrueObject = 'y',
kFalseObject = 'x',
// Number object. value:double
kNumberObject = 'n',
// String object, UTF-8 encoding. byteLength:uint32_t, then raw data.
kStringObject = 's',
// Regular expression, UTF-8 encoding. byteLength:uint32_t, raw data,
// flags:uint32_t.
kRegExp = 'R',
// Beginning of a JS map.
kBeginJSMap = ';',
// End of a JS map. length:uint32_t.
kEndJSMap = ':',
// Beginning of a JS set.
kBeginJSSet = '\'',
// End of a JS set. length:uint32_t.
kEndJSSet = ',',
// Array buffer. byteLength:uint32_t, then raw data.
kArrayBuffer = 'B',
// Array buffer (transferred). transferID:uint32_t
kArrayBufferTransfer = 't',
// View into an array buffer.
// subtag:ArrayBufferViewTag, byteOffset:uint32_t, byteLength:uint32_t
// For typed arrays, byteOffset and byteLength must be divisible by the size
// of the element.
// Note: kArrayBufferView is special, and should have an ArrayBuffer (or an
// ObjectReference to one) serialized just before it. This is a quirk arising
// from the previous stack-based implementation.
kArrayBufferView = 'V',
// Shared array buffer (transferred). transferID:uint32_t
kSharedArrayBufferTransfer = 'u',
};
namespace {
enum class ArrayBufferViewTag : uint8_t {
kInt8Array = 'b',
kUint8Array = 'B',
kUint8ClampedArray = 'C',
kInt16Array = 'w',
kUint16Array = 'W',
kInt32Array = 'd',
kUint32Array = 'D',
kFloat32Array = 'f',
kFloat64Array = 'F',
kDataView = '?',
};
} // namespace
ValueSerializer::ValueSerializer(Isolate* isolate,
v8::ValueSerializer::Delegate* delegate)
: isolate_(isolate),
delegate_(delegate),
zone_(isolate->allocator()),
id_map_(isolate->heap(), &zone_),
array_buffer_transfer_map_(isolate->heap(), &zone_) {}
ValueSerializer::~ValueSerializer() {}
void ValueSerializer::WriteHeader() {
WriteTag(SerializationTag::kVersion);
WriteVarint(kLatestVersion);
}
void ValueSerializer::WriteTag(SerializationTag tag) {
buffer_.push_back(static_cast<uint8_t>(tag));
}
template <typename T>
void ValueSerializer::WriteVarint(T value) {
// Writes an unsigned integer as a base-128 varint.
// The number is written, 7 bits at a time, from the least significant to the
// most significant 7 bits. Each byte, except the last, has the MSB set.
// See also https://developers.google.com/protocol-buffers/docs/encoding
static_assert(std::is_integral<T>::value && std::is_unsigned<T>::value,
"Only unsigned integer types can be written as varints.");
uint8_t stack_buffer[sizeof(T) * 8 / 7 + 1];
uint8_t* next_byte = &stack_buffer[0];
do {
*next_byte = (value & 0x7f) | 0x80;
next_byte++;
value >>= 7;
} while (value);
*(next_byte - 1) &= 0x7f;
buffer_.insert(buffer_.end(), stack_buffer, next_byte);
}
template <typename T>
void ValueSerializer::WriteZigZag(T value) {
// Writes a signed integer as a varint using ZigZag encoding (i.e. 0 is
// encoded as 0, -1 as 1, 1 as 2, -2 as 3, and so on).
// See also https://developers.google.com/protocol-buffers/docs/encoding
// Note that this implementation relies on the right shift being arithmetic.
static_assert(std::is_integral<T>::value && std::is_signed<T>::value,
"Only signed integer types can be written as zigzag.");
using UnsignedT = typename std::make_unsigned<T>::type;
WriteVarint((static_cast<UnsignedT>(value) << 1) ^
(value >> (8 * sizeof(T) - 1)));
}
void ValueSerializer::WriteDouble(double value) {
// Warning: this uses host endianness.
buffer_.insert(buffer_.end(), reinterpret_cast<const uint8_t*>(&value),
reinterpret_cast<const uint8_t*>(&value + 1));
}
void ValueSerializer::WriteOneByteString(Vector<const uint8_t> chars) {
WriteVarint<uint32_t>(chars.length());
buffer_.insert(buffer_.end(), chars.begin(), chars.end());
}
void ValueSerializer::WriteTwoByteString(Vector<const uc16> chars) {
// Warning: this uses host endianness.
WriteVarint<uint32_t>(chars.length() * sizeof(uc16));
buffer_.insert(buffer_.end(), reinterpret_cast<const uint8_t*>(chars.begin()),
reinterpret_cast<const uint8_t*>(chars.end()));
}
void ValueSerializer::WriteRawBytes(const void* source, size_t length) {
const uint8_t* begin = reinterpret_cast<const uint8_t*>(source);
buffer_.insert(buffer_.end(), begin, begin + length);
}
uint8_t* ValueSerializer::ReserveRawBytes(size_t bytes) {
if (!bytes) return nullptr;
auto old_size = buffer_.size();
buffer_.resize(buffer_.size() + bytes);
return &buffer_[old_size];
}
void ValueSerializer::WriteUint32(uint32_t value) {
WriteVarint<uint32_t>(value);
}
void ValueSerializer::WriteUint64(uint64_t value) {
WriteVarint<uint64_t>(value);
}
void ValueSerializer::TransferArrayBuffer(uint32_t transfer_id,
Handle<JSArrayBuffer> array_buffer) {
DCHECK(!array_buffer_transfer_map_.Find(array_buffer));
array_buffer_transfer_map_.Set(array_buffer, transfer_id);
}
Maybe<bool> ValueSerializer::WriteObject(Handle<Object> object) {
if (object->IsSmi()) {
WriteSmi(Smi::cast(*object));
return Just(true);
}
DCHECK(object->IsHeapObject());
switch (HeapObject::cast(*object)->map()->instance_type()) {
case ODDBALL_TYPE:
WriteOddball(Oddball::cast(*object));
return Just(true);
case HEAP_NUMBER_TYPE:
case MUTABLE_HEAP_NUMBER_TYPE:
WriteHeapNumber(HeapNumber::cast(*object));
return Just(true);
case JS_TYPED_ARRAY_TYPE:
case JS_DATA_VIEW_TYPE: {
// Despite being JSReceivers, these have their wrapped buffer serialized
// first. That makes this logic a little quirky, because it needs to
// happen before we assign object IDs.
// TODO(jbroman): It may be possible to avoid materializing a typed
// array's buffer here.
Handle<JSArrayBufferView> view = Handle<JSArrayBufferView>::cast(object);
if (!id_map_.Find(view)) {
Handle<JSArrayBuffer> buffer(
view->IsJSTypedArray()
? Handle<JSTypedArray>::cast(view)->GetBuffer()
: handle(JSArrayBuffer::cast(view->buffer()), isolate_));
if (!WriteJSReceiver(buffer).FromMaybe(false)) return Nothing<bool>();
}
return WriteJSReceiver(view);
}
default:
if (object->IsString()) {
WriteString(Handle<String>::cast(object));
return Just(true);
} else if (object->IsJSReceiver()) {
return WriteJSReceiver(Handle<JSReceiver>::cast(object));
} else {
ThrowDataCloneError(MessageTemplate::kDataCloneError, object);
return Nothing<bool>();
}
}
}
void ValueSerializer::WriteOddball(Oddball* oddball) {
SerializationTag tag = SerializationTag::kUndefined;
switch (oddball->kind()) {
case Oddball::kUndefined:
tag = SerializationTag::kUndefined;
break;
case Oddball::kFalse:
tag = SerializationTag::kFalse;
break;
case Oddball::kTrue:
tag = SerializationTag::kTrue;
break;
case Oddball::kNull:
tag = SerializationTag::kNull;
break;
default:
UNREACHABLE();
break;
}
WriteTag(tag);
}
void ValueSerializer::WriteSmi(Smi* smi) {
static_assert(kSmiValueSize <= 32, "Expected SMI <= 32 bits.");
WriteTag(SerializationTag::kInt32);
WriteZigZag<int32_t>(smi->value());
}
void ValueSerializer::WriteHeapNumber(HeapNumber* number) {
WriteTag(SerializationTag::kDouble);
WriteDouble(number->value());
}
void ValueSerializer::WriteString(Handle<String> string) {
string = String::Flatten(string);
DisallowHeapAllocation no_gc;
String::FlatContent flat = string->GetFlatContent();
DCHECK(flat.IsFlat());
if (flat.IsOneByte()) {
// The existing format uses UTF-8, rather than Latin-1. As a result we must
// to do work to encode strings that have characters outside ASCII.
// TODO(jbroman): In a future format version, consider adding a tag for
// Latin-1 strings, so that this can be skipped.
WriteTag(SerializationTag::kUtf8String);
Vector<const uint8_t> chars = flat.ToOneByteVector();
if (String::IsAscii(chars.begin(), chars.length())) {
WriteOneByteString(chars);
} else {
v8::Local<v8::String> api_string = Utils::ToLocal(string);
uint32_t utf8_length = api_string->Utf8Length();
WriteVarint(utf8_length);
api_string->WriteUtf8(
reinterpret_cast<char*>(ReserveRawBytes(utf8_length)), utf8_length,
nullptr, v8::String::NO_NULL_TERMINATION);
}
} else if (flat.IsTwoByte()) {
Vector<const uc16> chars = flat.ToUC16Vector();
uint32_t byte_length = chars.length() * sizeof(uc16);
// The existing reading code expects 16-byte strings to be aligned.
if ((buffer_.size() + 1 + BytesNeededForVarint(byte_length)) & 1)
WriteTag(SerializationTag::kPadding);
WriteTag(SerializationTag::kTwoByteString);
WriteTwoByteString(chars);
} else {
UNREACHABLE();
}
}
Maybe<bool> ValueSerializer::WriteJSReceiver(Handle<JSReceiver> receiver) {
// If the object has already been serialized, just write its ID.
uint32_t* id_map_entry = id_map_.Get(receiver);
if (uint32_t id = *id_map_entry) {
WriteTag(SerializationTag::kObjectReference);
WriteVarint(id - 1);
return Just(true);
}
// Otherwise, allocate an ID for it.
uint32_t id = next_id_++;
*id_map_entry = id + 1;
// Eliminate callable and exotic objects, which should not be serialized.
InstanceType instance_type = receiver->map()->instance_type();
if (receiver->IsCallable() || (instance_type <= LAST_SPECIAL_RECEIVER_TYPE &&
instance_type != JS_SPECIAL_API_OBJECT_TYPE)) {
ThrowDataCloneError(MessageTemplate::kDataCloneError, receiver);
return Nothing<bool>();
}
// If we are at the end of the stack, abort. This function may recurse.
STACK_CHECK(isolate_, Nothing<bool>());
HandleScope scope(isolate_);
switch (instance_type) {
case JS_ARRAY_TYPE:
return WriteJSArray(Handle<JSArray>::cast(receiver));
case JS_OBJECT_TYPE:
case JS_API_OBJECT_TYPE: {
Handle<JSObject> js_object = Handle<JSObject>::cast(receiver);
return js_object->GetInternalFieldCount() ? WriteHostObject(js_object)
: WriteJSObject(js_object);
}
case JS_SPECIAL_API_OBJECT_TYPE:
return WriteHostObject(Handle<JSObject>::cast(receiver));
case JS_DATE_TYPE:
WriteJSDate(JSDate::cast(*receiver));
return Just(true);
case JS_VALUE_TYPE:
return WriteJSValue(Handle<JSValue>::cast(receiver));
case JS_REGEXP_TYPE:
WriteJSRegExp(JSRegExp::cast(*receiver));
return Just(true);
case JS_MAP_TYPE:
return WriteJSMap(Handle<JSMap>::cast(receiver));
case JS_SET_TYPE:
return WriteJSSet(Handle<JSSet>::cast(receiver));
case JS_ARRAY_BUFFER_TYPE:
return WriteJSArrayBuffer(JSArrayBuffer::cast(*receiver));
case JS_TYPED_ARRAY_TYPE:
case JS_DATA_VIEW_TYPE:
return WriteJSArrayBufferView(JSArrayBufferView::cast(*receiver));
default:
ThrowDataCloneError(MessageTemplate::kDataCloneError, receiver);
return Nothing<bool>();
}
return Nothing<bool>();
}
Maybe<bool> ValueSerializer::WriteJSObject(Handle<JSObject> object) {
DCHECK_GT(object->map()->instance_type(), LAST_CUSTOM_ELEMENTS_RECEIVER);
const bool can_serialize_fast =
object->HasFastProperties() && object->elements()->length() == 0;
if (!can_serialize_fast) return WriteJSObjectSlow(object);
Handle<Map> map(object->map(), isolate_);
WriteTag(SerializationTag::kBeginJSObject);
// Write out fast properties as long as they are only data properties and the
// map doesn't change.
uint32_t properties_written = 0;
bool map_changed = false;
for (int i = 0; i < map->NumberOfOwnDescriptors(); i++) {
Handle<Name> key(map->instance_descriptors()->GetKey(i), isolate_);
if (!key->IsString()) continue;
PropertyDetails details = map->instance_descriptors()->GetDetails(i);
if (details.IsDontEnum()) continue;
Handle<Object> value;
if (V8_LIKELY(!map_changed)) map_changed = *map == object->map();
if (V8_LIKELY(!map_changed && details.type() == DATA)) {
FieldIndex field_index = FieldIndex::ForDescriptor(*map, i);
value = JSObject::FastPropertyAt(object, details.representation(),
field_index);
} else {
// This logic should essentially match WriteJSObjectPropertiesSlow.
// If the property is no longer found, do not serialize it.
// This could happen if a getter deleted the property.
LookupIterator it(isolate_, object, key, LookupIterator::OWN);
if (!it.IsFound()) continue;
if (!Object::GetProperty(&it).ToHandle(&value)) return Nothing<bool>();
}
if (!WriteObject(key).FromMaybe(false) ||
!WriteObject(value).FromMaybe(false)) {
return Nothing<bool>();
}
properties_written++;
}
WriteTag(SerializationTag::kEndJSObject);
WriteVarint<uint32_t>(properties_written);
return Just(true);
}
Maybe<bool> ValueSerializer::WriteJSObjectSlow(Handle<JSObject> object) {
WriteTag(SerializationTag::kBeginJSObject);
Handle<FixedArray> keys;
uint32_t properties_written;
if (!KeyAccumulator::GetKeys(object, KeyCollectionMode::kOwnOnly,
ENUMERABLE_STRINGS)
.ToHandle(&keys) ||
!WriteJSObjectPropertiesSlow(object, keys).To(&properties_written)) {
return Nothing<bool>();
}
WriteTag(SerializationTag::kEndJSObject);
WriteVarint<uint32_t>(properties_written);
return Just(true);
}
Maybe<bool> ValueSerializer::WriteJSArray(Handle<JSArray> array) {
uint32_t length = 0;
bool valid_length = array->length()->ToArrayLength(&length);
DCHECK(valid_length);
USE(valid_length);
// To keep things simple, for now we decide between dense and sparse
// serialization based on elements kind. A more principled heuristic could
// count the elements, but would need to take care to note which indices
// existed (as only indices which were enumerable own properties at this point
// should be serialized).
const bool should_serialize_densely =
array->HasFastElements() && !array->HasFastHoleyElements();
if (should_serialize_densely) {
// TODO(jbroman): Distinguish between undefined and a hole (this can happen
// if serializing one of the elements deletes another). This requires wire
// format changes.
WriteTag(SerializationTag::kBeginDenseJSArray);
WriteVarint<uint32_t>(length);
uint32_t i = 0;
// Fast paths. Note that FAST_ELEMENTS in particular can bail due to the
// structure of the elements changing.
switch (array->GetElementsKind()) {
case FAST_SMI_ELEMENTS: {
Handle<FixedArray> elements(FixedArray::cast(array->elements()),
isolate_);
for (; i < length; i++) WriteSmi(Smi::cast(elements->get(i)));
break;
}
case FAST_DOUBLE_ELEMENTS: {
Handle<FixedDoubleArray> elements(
FixedDoubleArray::cast(array->elements()), isolate_);
for (; i < length; i++) {
WriteTag(SerializationTag::kDouble);
WriteDouble(elements->get_scalar(i));
}
break;
}
case FAST_ELEMENTS: {
Handle<Object> old_length(array->length(), isolate_);
for (; i < length; i++) {
if (array->length() != *old_length ||
array->GetElementsKind() != FAST_ELEMENTS) {
// Fall back to slow path.
break;
}
Handle<Object> element(FixedArray::cast(array->elements())->get(i),
isolate_);
if (!WriteObject(element).FromMaybe(false)) return Nothing<bool>();
}
break;
}
default:
break;
}
// If there are elements remaining, serialize them slowly.
for (; i < length; i++) {
// Serializing the array's elements can have arbitrary side effects, so we
// cannot rely on still having fast elements, even if it did to begin
// with.
Handle<Object> element;
LookupIterator it(isolate_, array, i, array, LookupIterator::OWN);
if (!Object::GetProperty(&it).ToHandle(&element) ||
!WriteObject(element).FromMaybe(false)) {
return Nothing<bool>();
}
}
KeyAccumulator accumulator(isolate_, KeyCollectionMode::kOwnOnly,
ENUMERABLE_STRINGS);
if (!accumulator.CollectOwnPropertyNames(array, array).FromMaybe(false)) {
return Nothing<bool>();
}
Handle<FixedArray> keys =
accumulator.GetKeys(GetKeysConversion::kConvertToString);
uint32_t properties_written;
if (!WriteJSObjectPropertiesSlow(array, keys).To(&properties_written)) {
return Nothing<bool>();
}
WriteTag(SerializationTag::kEndDenseJSArray);
WriteVarint<uint32_t>(properties_written);
WriteVarint<uint32_t>(length);
} else {
WriteTag(SerializationTag::kBeginSparseJSArray);
WriteVarint<uint32_t>(length);
Handle<FixedArray> keys;
uint32_t properties_written;
if (!KeyAccumulator::GetKeys(array, KeyCollectionMode::kOwnOnly,
ENUMERABLE_STRINGS)
.ToHandle(&keys) ||
!WriteJSObjectPropertiesSlow(array, keys).To(&properties_written)) {
return Nothing<bool>();
}
WriteTag(SerializationTag::kEndSparseJSArray);
WriteVarint<uint32_t>(properties_written);
WriteVarint<uint32_t>(length);
}
return Just(true);
}
void ValueSerializer::WriteJSDate(JSDate* date) {
WriteTag(SerializationTag::kDate);
WriteDouble(date->value()->Number());
}
Maybe<bool> ValueSerializer::WriteJSValue(Handle<JSValue> value) {
Object* inner_value = value->value();
if (inner_value->IsTrue(isolate_)) {
WriteTag(SerializationTag::kTrueObject);
} else if (inner_value->IsFalse(isolate_)) {
WriteTag(SerializationTag::kFalseObject);
} else if (inner_value->IsNumber()) {
WriteTag(SerializationTag::kNumberObject);
WriteDouble(inner_value->Number());
} else if (inner_value->IsString()) {
// TODO(jbroman): Replace UTF-8 encoding with the same options available for
// ordinary strings.
WriteTag(SerializationTag::kStringObject);
v8::Local<v8::String> api_string =
Utils::ToLocal(handle(String::cast(inner_value), isolate_));
uint32_t utf8_length = api_string->Utf8Length();
WriteVarint(utf8_length);
api_string->WriteUtf8(reinterpret_cast<char*>(ReserveRawBytes(utf8_length)),
utf8_length, nullptr,
v8::String::NO_NULL_TERMINATION);
} else {
DCHECK(inner_value->IsSymbol());
ThrowDataCloneError(MessageTemplate::kDataCloneError, value);
return Nothing<bool>();
}
return Just(true);
}
void ValueSerializer::WriteJSRegExp(JSRegExp* regexp) {
WriteTag(SerializationTag::kRegExp);
v8::Local<v8::String> api_string =
Utils::ToLocal(handle(regexp->Pattern(), isolate_));
uint32_t utf8_length = api_string->Utf8Length();
WriteVarint(utf8_length);
api_string->WriteUtf8(reinterpret_cast<char*>(ReserveRawBytes(utf8_length)),
utf8_length, nullptr, v8::String::NO_NULL_TERMINATION);
WriteVarint(static_cast<uint32_t>(regexp->GetFlags()));
}
Maybe<bool> ValueSerializer::WriteJSMap(Handle<JSMap> map) {
// First copy the key-value pairs, since getters could mutate them.
Handle<OrderedHashMap> table(OrderedHashMap::cast(map->table()));
int length = table->NumberOfElements() * 2;
Handle<FixedArray> entries = isolate_->factory()->NewFixedArray(length);
{
DisallowHeapAllocation no_gc;
Oddball* the_hole = isolate_->heap()->the_hole_value();
int capacity = table->UsedCapacity();
int result_index = 0;
for (int i = 0; i < capacity; i++) {
Object* key = table->KeyAt(i);
if (key == the_hole) continue;
entries->set(result_index++, key);
entries->set(result_index++, table->ValueAt(i));
}
DCHECK_EQ(result_index, length);
}
// Then write it out.
WriteTag(SerializationTag::kBeginJSMap);
for (int i = 0; i < length; i++) {
if (!WriteObject(handle(entries->get(i), isolate_)).FromMaybe(false)) {
return Nothing<bool>();
}
}
WriteTag(SerializationTag::kEndJSMap);
WriteVarint<uint32_t>(length);
return Just(true);
}
Maybe<bool> ValueSerializer::WriteJSSet(Handle<JSSet> set) {
// First copy the element pointers, since getters could mutate them.
Handle<OrderedHashSet> table(OrderedHashSet::cast(set->table()));
int length = table->NumberOfElements();
Handle<FixedArray> entries = isolate_->factory()->NewFixedArray(length);
{
DisallowHeapAllocation no_gc;
Oddball* the_hole = isolate_->heap()->the_hole_value();
int capacity = table->UsedCapacity();
int result_index = 0;
for (int i = 0; i < capacity; i++) {
Object* key = table->KeyAt(i);
if (key == the_hole) continue;
entries->set(result_index++, key);
}
DCHECK_EQ(result_index, length);
}
// Then write it out.
WriteTag(SerializationTag::kBeginJSSet);
for (int i = 0; i < length; i++) {
if (!WriteObject(handle(entries->get(i), isolate_)).FromMaybe(false)) {
return Nothing<bool>();
}
}
WriteTag(SerializationTag::kEndJSSet);
WriteVarint<uint32_t>(length);
return Just(true);
}
Maybe<bool> ValueSerializer::WriteJSArrayBuffer(JSArrayBuffer* array_buffer) {
uint32_t* transfer_entry = array_buffer_transfer_map_.Find(array_buffer);
if (transfer_entry) {
DCHECK(array_buffer->was_neutered() || array_buffer->is_shared());
WriteTag(array_buffer->is_shared()
? SerializationTag::kSharedArrayBufferTransfer
: SerializationTag::kArrayBufferTransfer);
WriteVarint(*transfer_entry);
return Just(true);
}
if (array_buffer->is_shared()) {
ThrowDataCloneError(
MessageTemplate::kDataCloneErrorSharedArrayBufferNotTransferred);
return Nothing<bool>();
}
if (array_buffer->was_neutered()) {
ThrowDataCloneError(MessageTemplate::kDataCloneErrorNeuteredArrayBuffer);
return Nothing<bool>();
}
double byte_length = array_buffer->byte_length()->Number();
if (byte_length > std::numeric_limits<uint32_t>::max()) {
ThrowDataCloneError(MessageTemplate::kDataCloneError, handle(array_buffer));
return Nothing<bool>();
}
WriteTag(SerializationTag::kArrayBuffer);
WriteVarint<uint32_t>(byte_length);
WriteRawBytes(array_buffer->backing_store(), byte_length);
return Just(true);
}
Maybe<bool> ValueSerializer::WriteJSArrayBufferView(JSArrayBufferView* view) {
WriteTag(SerializationTag::kArrayBufferView);
ArrayBufferViewTag tag = ArrayBufferViewTag::kInt8Array;
if (view->IsJSTypedArray()) {
switch (JSTypedArray::cast(view)->type()) {
#define TYPED_ARRAY_CASE(Type, type, TYPE, ctype, size) \
case kExternal##Type##Array: \
tag = ArrayBufferViewTag::k##Type##Array; \
break;
TYPED_ARRAYS(TYPED_ARRAY_CASE)
#undef TYPED_ARRAY_CASE
}
} else {
DCHECK(view->IsJSDataView());
tag = ArrayBufferViewTag::kDataView;
}
WriteVarint(static_cast<uint8_t>(tag));
WriteVarint(NumberToUint32(view->byte_offset()));
WriteVarint(NumberToUint32(view->byte_length()));
return Just(true);
}
Maybe<bool> ValueSerializer::WriteHostObject(Handle<JSObject> object) {
if (!delegate_) {
isolate_->Throw(*isolate_->factory()->NewError(
isolate_->error_function(), MessageTemplate::kDataCloneError, object));
return Nothing<bool>();
}
v8::Isolate* v8_isolate = reinterpret_cast<v8::Isolate*>(isolate_);
Maybe<bool> result =
delegate_->WriteHostObject(v8_isolate, Utils::ToLocal(object));
RETURN_VALUE_IF_SCHEDULED_EXCEPTION(isolate_, Nothing<bool>());
DCHECK(!result.IsNothing());
return result;
}
Maybe<uint32_t> ValueSerializer::WriteJSObjectPropertiesSlow(
Handle<JSObject> object, Handle<FixedArray> keys) {
uint32_t properties_written = 0;
int length = keys->length();
for (int i = 0; i < length; i++) {
Handle<Object> key(keys->get(i), isolate_);
bool success;
LookupIterator it = LookupIterator::PropertyOrElement(
isolate_, object, key, &success, LookupIterator::OWN);
DCHECK(success);
Handle<Object> value;
if (!Object::GetProperty(&it).ToHandle(&value)) return Nothing<uint32_t>();
// If the property is no longer found, do not serialize it.
// This could happen if a getter deleted the property.
if (!it.IsFound()) continue;
if (!WriteObject(key).FromMaybe(false) ||
!WriteObject(value).FromMaybe(false)) {
return Nothing<uint32_t>();
}
properties_written++;
}
return Just(properties_written);
}
void ValueSerializer::ThrowDataCloneError(
MessageTemplate::Template template_index) {
return ThrowDataCloneError(template_index,
isolate_->factory()->empty_string());
}
void ValueSerializer::ThrowDataCloneError(
MessageTemplate::Template template_index, Handle<Object> arg0) {
Handle<String> message =
MessageTemplate::FormatMessage(isolate_, template_index, arg0);
if (delegate_) {
delegate_->ThrowDataCloneError(Utils::ToLocal(message));
} else {
isolate_->Throw(
*isolate_->factory()->NewError(isolate_->error_function(), message));
}
if (isolate_->has_scheduled_exception()) {
isolate_->PromoteScheduledException();
}
}
ValueDeserializer::ValueDeserializer(Isolate* isolate,
Vector<const uint8_t> data,
v8::ValueDeserializer::Delegate* delegate)
: isolate_(isolate),
delegate_(delegate),
position_(data.start()),
end_(data.start() + data.length()),
pretenure_(data.length() > kPretenureThreshold ? TENURED : NOT_TENURED),
id_map_(Handle<FixedArray>::cast(isolate->global_handles()->Create(
isolate_->heap()->empty_fixed_array()))) {}
ValueDeserializer::~ValueDeserializer() {
GlobalHandles::Destroy(Handle<Object>::cast(id_map_).location());
Handle<Object> transfer_map_handle;
if (array_buffer_transfer_map_.ToHandle(&transfer_map_handle)) {
GlobalHandles::Destroy(transfer_map_handle.location());
}
}
Maybe<bool> ValueDeserializer::ReadHeader() {
if (position_ < end_ &&
*position_ == static_cast<uint8_t>(SerializationTag::kVersion)) {
ReadTag().ToChecked();
if (!ReadVarint<uint32_t>().To(&version_) || version_ > kLatestVersion) {
isolate_->Throw(*isolate_->factory()->NewError(
MessageTemplate::kDataCloneDeserializationVersionError));
return Nothing<bool>();
}
}
return Just(true);
}
Maybe<SerializationTag> ValueDeserializer::PeekTag() const {
const uint8_t* peek_position = position_;
SerializationTag tag;
do {
if (peek_position >= end_) return Nothing<SerializationTag>();
tag = static_cast<SerializationTag>(*peek_position);
peek_position++;
} while (tag == SerializationTag::kPadding);
return Just(tag);
}
void ValueDeserializer::ConsumeTag(SerializationTag peeked_tag) {
SerializationTag actual_tag = ReadTag().ToChecked();
DCHECK(actual_tag == peeked_tag);
USE(actual_tag);
}
Maybe<SerializationTag> ValueDeserializer::ReadTag() {
SerializationTag tag;
do {
if (position_ >= end_) return Nothing<SerializationTag>();
tag = static_cast<SerializationTag>(*position_);
position_++;
} while (tag == SerializationTag::kPadding);
return Just(tag);
}
template <typename T>
Maybe<T> ValueDeserializer::ReadVarint() {
// Reads an unsigned integer as a base-128 varint.
// The number is written, 7 bits at a time, from the least significant to the
// most significant 7 bits. Each byte, except the last, has the MSB set.
// If the varint is larger than T, any more significant bits are discarded.
// See also https://developers.google.com/protocol-buffers/docs/encoding
static_assert(std::is_integral<T>::value && std::is_unsigned<T>::value,
"Only unsigned integer types can be read as varints.");
T value = 0;
unsigned shift = 0;
bool has_another_byte;
do {
if (position_ >= end_) return Nothing<T>();
uint8_t byte = *position_;
if (V8_LIKELY(shift < sizeof(T) * 8)) {
value |= static_cast<T>(byte & 0x7f) << shift;
shift += 7;
}
has_another_byte = byte & 0x80;
position_++;
} while (has_another_byte);
return Just(value);
}
template <typename T>
Maybe<T> ValueDeserializer::ReadZigZag() {
// Writes a signed integer as a varint using ZigZag encoding (i.e. 0 is
// encoded as 0, -1 as 1, 1 as 2, -2 as 3, and so on).
// See also https://developers.google.com/protocol-buffers/docs/encoding
static_assert(std::is_integral<T>::value && std::is_signed<T>::value,
"Only signed integer types can be read as zigzag.");
using UnsignedT = typename std::make_unsigned<T>::type;
UnsignedT unsigned_value;
if (!ReadVarint<UnsignedT>().To(&unsigned_value)) return Nothing<T>();
return Just(static_cast<T>((unsigned_value >> 1) ^
-static_cast<T>(unsigned_value & 1)));
}
Maybe<double> ValueDeserializer::ReadDouble() {
// Warning: this uses host endianness.
if (position_ > end_ - sizeof(double)) return Nothing<double>();
double value;
memcpy(&value, position_, sizeof(double));
position_ += sizeof(double);
if (std::isnan(value)) value = std::numeric_limits<double>::quiet_NaN();
return Just(value);
}
Maybe<Vector<const uint8_t>> ValueDeserializer::ReadRawBytes(int size) {
if (size > end_ - position_) return Nothing<Vector<const uint8_t>>();
const uint8_t* start = position_;
position_ += size;
return Just(Vector<const uint8_t>(start, size));
}
bool ValueDeserializer::ReadUint32(uint32_t* value) {
return ReadVarint<uint32_t>().To(value);
}
bool ValueDeserializer::ReadUint64(uint64_t* value) {
return ReadVarint<uint64_t>().To(value);
}
bool ValueDeserializer::ReadDouble(double* value) {
return ReadDouble().To(value);
}
bool ValueDeserializer::ReadRawBytes(size_t length, const void** data) {
if (length > static_cast<size_t>(end_ - position_)) return false;
*data = position_;
position_ += length;
return true;
}
void ValueDeserializer::TransferArrayBuffer(
uint32_t transfer_id, Handle<JSArrayBuffer> array_buffer) {
if (array_buffer_transfer_map_.is_null()) {
array_buffer_transfer_map_ =
Handle<SeededNumberDictionary>::cast(isolate_->global_handles()->Create(
*SeededNumberDictionary::New(isolate_, 0)));
}
Handle<SeededNumberDictionary> dictionary =
array_buffer_transfer_map_.ToHandleChecked();
const bool used_as_prototype = false;
Handle<SeededNumberDictionary> new_dictionary =
SeededNumberDictionary::AtNumberPut(dictionary, transfer_id, array_buffer,
used_as_prototype);
if (!new_dictionary.is_identical_to(dictionary)) {
GlobalHandles::Destroy(Handle<Object>::cast(dictionary).location());
array_buffer_transfer_map_ = Handle<SeededNumberDictionary>::cast(
isolate_->global_handles()->Create(*new_dictionary));
}
}
MaybeHandle<Object> ValueDeserializer::ReadObject() {
MaybeHandle<Object> result = ReadObjectInternal();
// ArrayBufferView is special in that it consumes the value before it, even
// after format version 0.
Handle<Object> object;
SerializationTag tag;
if (result.ToHandle(&object) && V8_UNLIKELY(object->IsJSArrayBuffer()) &&
PeekTag().To(&tag) && tag == SerializationTag::kArrayBufferView) {
ConsumeTag(SerializationTag::kArrayBufferView);
result = ReadJSArrayBufferView(Handle<JSArrayBuffer>::cast(object));
}
if (result.is_null() && !isolate_->has_pending_exception()) {
isolate_->Throw(*isolate_->factory()->NewError(
MessageTemplate::kDataCloneDeserializationError));
}
return result;
}
MaybeHandle<Object> ValueDeserializer::ReadObjectInternal() {
SerializationTag tag;
if (!ReadTag().To(&tag)) return MaybeHandle<Object>();
switch (tag) {
case SerializationTag::kVerifyObjectCount:
// Read the count and ignore it.
if (ReadVarint<uint32_t>().IsNothing()) return MaybeHandle<Object>();
return ReadObject();
case SerializationTag::kUndefined:
return isolate_->factory()->undefined_value();
case SerializationTag::kNull:
return isolate_->factory()->null_value();
case SerializationTag::kTrue:
return isolate_->factory()->true_value();
case SerializationTag::kFalse:
return isolate_->factory()->false_value();
case SerializationTag::kInt32: {
Maybe<int32_t> number = ReadZigZag<int32_t>();
if (number.IsNothing()) return MaybeHandle<Object>();
return isolate_->factory()->NewNumberFromInt(number.FromJust(),
pretenure_);
}
case SerializationTag::kUint32: {
Maybe<uint32_t> number = ReadVarint<uint32_t>();
if (number.IsNothing()) return MaybeHandle<Object>();
return isolate_->factory()->NewNumberFromUint(number.FromJust(),
pretenure_);
}
case SerializationTag::kDouble: {
Maybe<double> number = ReadDouble();
if (number.IsNothing()) return MaybeHandle<Object>();
return isolate_->factory()->NewNumber(number.FromJust(), pretenure_);
}
case SerializationTag::kUtf8String:
return ReadUtf8String();
case SerializationTag::kTwoByteString:
return ReadTwoByteString();
case SerializationTag::kObjectReference: {
uint32_t id;
if (!ReadVarint<uint32_t>().To(&id)) return MaybeHandle<Object>();
return GetObjectWithID(id);
}
case SerializationTag::kBeginJSObject:
return ReadJSObject();
case SerializationTag::kBeginSparseJSArray:
return ReadSparseJSArray();
case SerializationTag::kBeginDenseJSArray:
return ReadDenseJSArray();
case SerializationTag::kDate:
return ReadJSDate();
case SerializationTag::kTrueObject:
case SerializationTag::kFalseObject:
case SerializationTag::kNumberObject:
case SerializationTag::kStringObject:
return ReadJSValue(tag);
case SerializationTag::kRegExp:
return ReadJSRegExp();
case SerializationTag::kBeginJSMap:
return ReadJSMap();
case SerializationTag::kBeginJSSet:
return ReadJSSet();
case SerializationTag::kArrayBuffer:
return ReadJSArrayBuffer();
case SerializationTag::kArrayBufferTransfer: {
const bool is_shared = false;
return ReadTransferredJSArrayBuffer(is_shared);
}
case SerializationTag::kSharedArrayBufferTransfer: {
const bool is_shared = true;
return ReadTransferredJSArrayBuffer(is_shared);
}
default:
// TODO(jbroman): Introduce an explicit tag for host objects to avoid
// having to treat every unknown tag as a potential host object.
position_--;
return ReadHostObject();
}
}
MaybeHandle<String> ValueDeserializer::ReadUtf8String() {
uint32_t utf8_length;
Vector<const uint8_t> utf8_bytes;
if (!ReadVarint<uint32_t>().To(&utf8_length) ||
utf8_length >
static_cast<uint32_t>(std::numeric_limits<int32_t>::max()) ||
!ReadRawBytes(utf8_length).To(&utf8_bytes))
return MaybeHandle<String>();
return isolate_->factory()->NewStringFromUtf8(
Vector<const char>::cast(utf8_bytes), pretenure_);
}
MaybeHandle<String> ValueDeserializer::ReadTwoByteString() {
uint32_t byte_length;
Vector<const uint8_t> bytes;
if (!ReadVarint<uint32_t>().To(&byte_length) ||
byte_length >
static_cast<uint32_t>(std::numeric_limits<int32_t>::max()) ||
byte_length % sizeof(uc16) != 0 || !ReadRawBytes(byte_length).To(&bytes))
return MaybeHandle<String>();
// Allocate an uninitialized string so that we can do a raw memcpy into the
// string on the heap (regardless of alignment).
Handle<SeqTwoByteString> string;
if (!isolate_->factory()
->NewRawTwoByteString(byte_length / sizeof(uc16), pretenure_)
.ToHandle(&string))
return MaybeHandle<String>();
// Copy the bytes directly into the new string.
// Warning: this uses host endianness.
memcpy(string->GetChars(), bytes.begin(), bytes.length());
return string;
}
bool ValueDeserializer::ReadExpectedString(Handle<String> expected) {
// In the case of failure, the position in the stream is reset.
const uint8_t* original_position = position_;
SerializationTag tag;
uint32_t byte_length;
Vector<const uint8_t> bytes;
if (!ReadTag().To(&tag) || !ReadVarint<uint32_t>().To(&byte_length) ||
byte_length >
static_cast<uint32_t>(std::numeric_limits<int32_t>::max()) ||
!ReadRawBytes(byte_length).To(&bytes)) {
position_ = original_position;
return false;
}
expected = String::Flatten(expected);
DisallowHeapAllocation no_gc;
String::FlatContent flat = expected->GetFlatContent();
// If the bytes are verbatim what is in the flattened string, then the string
// is successfully consumed.
if (tag == SerializationTag::kUtf8String && flat.IsOneByte()) {
Vector<const uint8_t> chars = flat.ToOneByteVector();
if (byte_length == chars.length() &&
String::IsAscii(chars.begin(), chars.length()) &&
memcmp(bytes.begin(), chars.begin(), byte_length) == 0) {
return true;
}
} else if (tag == SerializationTag::kTwoByteString && flat.IsTwoByte()) {
Vector<const uc16> chars = flat.ToUC16Vector();
if (byte_length == static_cast<unsigned>(chars.length()) * sizeof(uc16) &&
memcmp(bytes.begin(), chars.begin(), byte_length) == 0) {
return true;
}
}
position_ = original_position;
return false;
}
MaybeHandle<JSObject> ValueDeserializer::ReadJSObject() {
// If we are at the end of the stack, abort. This function may recurse.
STACK_CHECK(isolate_, MaybeHandle<JSObject>());
uint32_t id = next_id_++;
HandleScope scope(isolate_);
Handle<JSObject> object =
isolate_->factory()->NewJSObject(isolate_->object_function(), pretenure_);
AddObjectWithID(id, object);
uint32_t num_properties;
uint32_t expected_num_properties;
if (!ReadJSObjectProperties(object, SerializationTag::kEndJSObject, true)
.To(&num_properties) ||
!ReadVarint<uint32_t>().To(&expected_num_properties) ||
num_properties != expected_num_properties) {
return MaybeHandle<JSObject>();
}
DCHECK(HasObjectWithID(id));
return scope.CloseAndEscape(object);
}
MaybeHandle<JSArray> ValueDeserializer::ReadSparseJSArray() {
// If we are at the end of the stack, abort. This function may recurse.
STACK_CHECK(isolate_, MaybeHandle<JSArray>());
uint32_t length;
if (!ReadVarint<uint32_t>().To(&length)) return MaybeHandle<JSArray>();
uint32_t id = next_id_++;
HandleScope scope(isolate_);
Handle<JSArray> array = isolate_->factory()->NewJSArray(
0, TERMINAL_FAST_ELEMENTS_KIND, pretenure_);
JSArray::SetLength(array, length);
AddObjectWithID(id, array);
uint32_t num_properties;
uint32_t expected_num_properties;
uint32_t expected_length;
if (!ReadJSObjectProperties(array, SerializationTag::kEndSparseJSArray, false)
.To(&num_properties) ||
!ReadVarint<uint32_t>().To(&expected_num_properties) ||
!ReadVarint<uint32_t>().To(&expected_length) ||
num_properties != expected_num_properties || length != expected_length) {
return MaybeHandle<JSArray>();
}
DCHECK(HasObjectWithID(id));
return scope.CloseAndEscape(array);
}
MaybeHandle<JSArray> ValueDeserializer::ReadDenseJSArray() {
// If we are at the end of the stack, abort. This function may recurse.
STACK_CHECK(isolate_, MaybeHandle<JSArray>());
uint32_t length;
if (!ReadVarint<uint32_t>().To(&length)) return MaybeHandle<JSArray>();
uint32_t id = next_id_++;
HandleScope scope(isolate_);
Handle<JSArray> array = isolate_->factory()->NewJSArray(
FAST_HOLEY_ELEMENTS, length, length, INITIALIZE_ARRAY_ELEMENTS_WITH_HOLE,
pretenure_);
AddObjectWithID(id, array);
Handle<FixedArray> elements(FixedArray::cast(array->elements()), isolate_);
for (uint32_t i = 0; i < length; i++) {
Handle<Object> element;
if (!ReadObject().ToHandle(&element)) return MaybeHandle<JSArray>();
// TODO(jbroman): Distinguish between undefined and a hole.
if (element->IsUndefined(isolate_)) continue;
elements->set(i, *element);
}
uint32_t num_properties;
uint32_t expected_num_properties;
uint32_t expected_length;
if (!ReadJSObjectProperties(array, SerializationTag::kEndDenseJSArray, false)
.To(&num_properties) ||
!ReadVarint<uint32_t>().To(&expected_num_properties) ||
!ReadVarint<uint32_t>().To(&expected_length) ||
num_properties != expected_num_properties || length != expected_length) {
return MaybeHandle<JSArray>();
}
DCHECK(HasObjectWithID(id));
return scope.CloseAndEscape(array);
}
MaybeHandle<JSDate> ValueDeserializer::ReadJSDate() {
double value;
if (!ReadDouble().To(&value)) return MaybeHandle<JSDate>();
uint32_t id = next_id_++;
Handle<JSDate> date;
if (!JSDate::New(isolate_->date_function(), isolate_->date_function(), value)
.ToHandle(&date)) {
return MaybeHandle<JSDate>();
}
AddObjectWithID(id, date);
return date;
}
MaybeHandle<JSValue> ValueDeserializer::ReadJSValue(SerializationTag tag) {
uint32_t id = next_id_++;
Handle<JSValue> value;
switch (tag) {
case SerializationTag::kTrueObject:
value = Handle<JSValue>::cast(isolate_->factory()->NewJSObject(
isolate_->boolean_function(), pretenure_));
value->set_value(isolate_->heap()->true_value());
break;
case SerializationTag::kFalseObject:
value = Handle<JSValue>::cast(isolate_->factory()->NewJSObject(
isolate_->boolean_function(), pretenure_));
value->set_value(isolate_->heap()->false_value());
break;
case SerializationTag::kNumberObject: {
double number;
if (!ReadDouble().To(&number)) return MaybeHandle<JSValue>();
value = Handle<JSValue>::cast(isolate_->factory()->NewJSObject(
isolate_->number_function(), pretenure_));
Handle<Object> number_object =
isolate_->factory()->NewNumber(number, pretenure_);
value->set_value(*number_object);
break;
}
case SerializationTag::kStringObject: {
Handle<String> string;
if (!ReadUtf8String().ToHandle(&string)) return MaybeHandle<JSValue>();
value = Handle<JSValue>::cast(isolate_->factory()->NewJSObject(
isolate_->string_function(), pretenure_));
value->set_value(*string);
break;
}
default:
UNREACHABLE();
return MaybeHandle<JSValue>();
}
AddObjectWithID(id, value);
return value;
}
MaybeHandle<JSRegExp> ValueDeserializer::ReadJSRegExp() {
uint32_t id = next_id_++;
Handle<String> pattern;
uint32_t raw_flags;
Handle<JSRegExp> regexp;
if (!ReadUtf8String().ToHandle(&pattern) ||
!ReadVarint<uint32_t>().To(&raw_flags) ||
!JSRegExp::New(pattern, static_cast<JSRegExp::Flags>(raw_flags))
.ToHandle(&regexp)) {
return MaybeHandle<JSRegExp>();
}
AddObjectWithID(id, regexp);
return regexp;
}
MaybeHandle<JSMap> ValueDeserializer::ReadJSMap() {
// If we are at the end of the stack, abort. This function may recurse.
STACK_CHECK(isolate_, MaybeHandle<JSMap>());
HandleScope scope(isolate_);
uint32_t id = next_id_++;
Handle<JSMap> map = isolate_->factory()->NewJSMap();
AddObjectWithID(id, map);
Handle<JSFunction> map_set = isolate_->map_set();
uint32_t length = 0;
while (true) {
SerializationTag tag;
if (!PeekTag().To(&tag)) return MaybeHandle<JSMap>();
if (tag == SerializationTag::kEndJSMap) {
ConsumeTag(SerializationTag::kEndJSMap);
break;
}
Handle<Object> argv[2];
if (!ReadObject().ToHandle(&argv[0]) || !ReadObject().ToHandle(&argv[1]) ||
Execution::Call(isolate_, map_set, map, arraysize(argv), argv)
.is_null()) {
return MaybeHandle<JSMap>();
}
length += 2;
}
uint32_t expected_length;
if (!ReadVarint<uint32_t>().To(&expected_length) ||
length != expected_length) {
return MaybeHandle<JSMap>();
}
DCHECK(HasObjectWithID(id));
return scope.CloseAndEscape(map);
}
MaybeHandle<JSSet> ValueDeserializer::ReadJSSet() {
// If we are at the end of the stack, abort. This function may recurse.
STACK_CHECK(isolate_, MaybeHandle<JSSet>());
HandleScope scope(isolate_);
uint32_t id = next_id_++;
Handle<JSSet> set = isolate_->factory()->NewJSSet();
AddObjectWithID(id, set);
Handle<JSFunction> set_add = isolate_->set_add();
uint32_t length = 0;
while (true) {
SerializationTag tag;
if (!PeekTag().To(&tag)) return MaybeHandle<JSSet>();
if (tag == SerializationTag::kEndJSSet) {
ConsumeTag(SerializationTag::kEndJSSet);
break;
}
Handle<Object> argv[1];
if (!ReadObject().ToHandle(&argv[0]) ||
Execution::Call(isolate_, set_add, set, arraysize(argv), argv)
.is_null()) {
return MaybeHandle<JSSet>();
}
length++;
}
uint32_t expected_length;
if (!ReadVarint<uint32_t>().To(&expected_length) ||
length != expected_length) {
return MaybeHandle<JSSet>();
}
DCHECK(HasObjectWithID(id));
return scope.CloseAndEscape(set);
}
MaybeHandle<JSArrayBuffer> ValueDeserializer::ReadJSArrayBuffer() {
uint32_t id = next_id_++;
uint32_t byte_length;
Vector<const uint8_t> bytes;
if (!ReadVarint<uint32_t>().To(&byte_length) ||
byte_length > static_cast<size_t>(end_ - position_)) {
return MaybeHandle<JSArrayBuffer>();
}
const bool should_initialize = false;
Handle<JSArrayBuffer> array_buffer =
isolate_->factory()->NewJSArrayBuffer(SharedFlag::kNotShared, pretenure_);
JSArrayBuffer::SetupAllocatingData(array_buffer, isolate_, byte_length,
should_initialize);
memcpy(array_buffer->backing_store(), position_, byte_length);
position_ += byte_length;
AddObjectWithID(id, array_buffer);
return array_buffer;
}
MaybeHandle<JSArrayBuffer> ValueDeserializer::ReadTransferredJSArrayBuffer(
bool is_shared) {
uint32_t id = next_id_++;
uint32_t transfer_id;
Handle<SeededNumberDictionary> transfer_map;
if (!ReadVarint<uint32_t>().To(&transfer_id) ||
!array_buffer_transfer_map_.ToHandle(&transfer_map)) {
return MaybeHandle<JSArrayBuffer>();
}
int index = transfer_map->FindEntry(isolate_, transfer_id);
if (index == SeededNumberDictionary::kNotFound) {
return MaybeHandle<JSArrayBuffer>();
}
Handle<JSArrayBuffer> array_buffer(
JSArrayBuffer::cast(transfer_map->ValueAt(index)), isolate_);
DCHECK_EQ(is_shared, array_buffer->is_shared());
AddObjectWithID(id, array_buffer);
return array_buffer;
}
MaybeHandle<JSArrayBufferView> ValueDeserializer::ReadJSArrayBufferView(
Handle<JSArrayBuffer> buffer) {
uint32_t buffer_byte_length = NumberToUint32(buffer->byte_length());
uint8_t tag = 0;
uint32_t byte_offset = 0;
uint32_t byte_length = 0;
if (!ReadVarint<uint8_t>().To(&tag) ||
!ReadVarint<uint32_t>().To(&byte_offset) ||
!ReadVarint<uint32_t>().To(&byte_length) ||
byte_offset > buffer_byte_length ||
byte_length > buffer_byte_length - byte_offset) {
return MaybeHandle<JSArrayBufferView>();
}
uint32_t id = next_id_++;
ExternalArrayType external_array_type = kExternalInt8Array;
unsigned element_size = 0;
switch (static_cast<ArrayBufferViewTag>(tag)) {
case ArrayBufferViewTag::kDataView: {
Handle<JSDataView> data_view =
isolate_->factory()->NewJSDataView(buffer, byte_offset, byte_length);
AddObjectWithID(id, data_view);
return data_view;
}
#define TYPED_ARRAY_CASE(Type, type, TYPE, ctype, size) \
case ArrayBufferViewTag::k##Type##Array: \
external_array_type = kExternal##Type##Array; \
element_size = size; \
break;
TYPED_ARRAYS(TYPED_ARRAY_CASE)
#undef TYPED_ARRAY_CASE
}
if (byte_offset % element_size != 0 || byte_length % element_size != 0) {
return MaybeHandle<JSArrayBufferView>();
}
Handle<JSTypedArray> typed_array = isolate_->factory()->NewJSTypedArray(
external_array_type, buffer, byte_offset, byte_length / element_size,
pretenure_);
AddObjectWithID(id, typed_array);
return typed_array;
}
MaybeHandle<JSObject> ValueDeserializer::ReadHostObject() {
if (!delegate_) return MaybeHandle<JSObject>();
STACK_CHECK(isolate_, MaybeHandle<JSObject>());
uint32_t id = next_id_++;
v8::Isolate* v8_isolate = reinterpret_cast<v8::Isolate*>(isolate_);
v8::Local<v8::Object> object;
if (!delegate_->ReadHostObject(v8_isolate).ToLocal(&object)) {
RETURN_EXCEPTION_IF_SCHEDULED_EXCEPTION(isolate_, JSObject);
return MaybeHandle<JSObject>();
}
Handle<JSObject> js_object =
Handle<JSObject>::cast(Utils::OpenHandle(*object));
AddObjectWithID(id, js_object);
return js_object;
}
// Copies a vector of property values into an object, given the map that should
// be used.
static void CommitProperties(Handle<JSObject> object, Handle<Map> map,
const std::vector<Handle<Object>>& properties) {
JSObject::AllocateStorageForMap(object, map);
DCHECK(!object->map()->is_dictionary_map());
DisallowHeapAllocation no_gc;
DescriptorArray* descriptors = object->map()->instance_descriptors();
for (unsigned i = 0; i < properties.size(); i++) {
object->WriteToField(i, descriptors->GetDetails(i), *properties[i]);
}
}
Maybe<uint32_t> ValueDeserializer::ReadJSObjectProperties(
Handle<JSObject> object, SerializationTag end_tag,
bool can_use_transitions) {
uint32_t num_properties = 0;
// Fast path (following map transitions).
if (can_use_transitions) {
bool transitioning = true;
Handle<Map> map(object->map(), isolate_);
DCHECK(!map->is_dictionary_map());
DCHECK(map->instance_descriptors()->IsEmpty());
std::vector<Handle<Object>> properties;
properties.reserve(8);
while (transitioning) {
// If there are no more properties, finish.
SerializationTag tag;
if (!PeekTag().To(&tag)) return Nothing<uint32_t>();
if (tag == end_tag) {
ConsumeTag(end_tag);
CommitProperties(object, map, properties);
CHECK_LT(properties.size(), std::numeric_limits<uint32_t>::max());
return Just(static_cast<uint32_t>(properties.size()));
}
// Determine the key to be used and the target map to transition to, if
// possible. Transitioning may abort if the key is not a string, or if no
// transition was found.
Handle<Object> key;
Handle<Map> target;
Handle<String> expected_key = TransitionArray::ExpectedTransitionKey(map);
if (!expected_key.is_null() && ReadExpectedString(expected_key)) {
key = expected_key;
target = TransitionArray::ExpectedTransitionTarget(map);
} else {
if (!ReadObject().ToHandle(&key)) return Nothing<uint32_t>();
if (key->IsString()) {
key =
isolate_->factory()->InternalizeString(Handle<String>::cast(key));
target = TransitionArray::FindTransitionToField(
map, Handle<String>::cast(key));
transitioning = !target.is_null();
} else {
transitioning = false;
}
}
// Read the value that corresponds to it.
Handle<Object> value;
if (!ReadObject().ToHandle(&value)) return Nothing<uint32_t>();
// If still transitioning and the value fits the field representation
// (though generalization may be required), store the property value so
// that we can copy them all at once. Otherwise, stop transitioning.
if (transitioning) {
int descriptor = static_cast<int>(properties.size());
PropertyDetails details =
target->instance_descriptors()->GetDetails(descriptor);
Representation expected_representation = details.representation();
if (value->FitsRepresentation(expected_representation)) {
if (expected_representation.IsHeapObject() &&
!target->instance_descriptors()
->GetFieldType(descriptor)
->NowContains(value)) {
Handle<FieldType> value_type =
value->OptimalType(isolate_, expected_representation);
Map::GeneralizeFieldType(target, descriptor,
expected_representation, value_type);
}
DCHECK(target->instance_descriptors()
->GetFieldType(descriptor)
->NowContains(value));
properties.push_back(value);
map = target;
continue;
} else {
transitioning = false;
}
}
// Fell out of transitioning fast path. Commit the properties gathered so
// far, and then start setting properties slowly instead.
DCHECK(!transitioning);
CHECK_LT(properties.size(), std::numeric_limits<uint32_t>::max());
CommitProperties(object, map, properties);
num_properties = static_cast<uint32_t>(properties.size());
bool success;
LookupIterator it = LookupIterator::PropertyOrElement(
isolate_, object, key, &success, LookupIterator::OWN);
if (!success ||
JSObject::DefineOwnPropertyIgnoreAttributes(&it, value, NONE)
.is_null()) {
return Nothing<uint32_t>();
}
num_properties++;
}
// At this point, transitioning should be done, but at least one property
// should have been written (in the zero-property case, there is an early
// return).
DCHECK(!transitioning);
DCHECK_GE(num_properties, 1u);
}
// Slow path.
for (;; num_properties++) {
SerializationTag tag;
if (!PeekTag().To(&tag)) return Nothing<uint32_t>();
if (tag == end_tag) {
ConsumeTag(end_tag);
return Just(num_properties);
}
Handle<Object> key;
if (!ReadObject().ToHandle(&key)) return Nothing<uint32_t>();
Handle<Object> value;
if (!ReadObject().ToHandle(&value)) return Nothing<uint32_t>();
bool success;
LookupIterator it = LookupIterator::PropertyOrElement(
isolate_, object, key, &success, LookupIterator::OWN);
if (!success ||
JSObject::DefineOwnPropertyIgnoreAttributes(&it, value, NONE)
.is_null()) {
return Nothing<uint32_t>();
}
}
}
bool ValueDeserializer::HasObjectWithID(uint32_t id) {
return id < static_cast<unsigned>(id_map_->length()) &&
!id_map_->get(id)->IsTheHole(isolate_);
}
MaybeHandle<JSReceiver> ValueDeserializer::GetObjectWithID(uint32_t id) {
if (id >= static_cast<unsigned>(id_map_->length())) {
return MaybeHandle<JSReceiver>();
}
Object* value = id_map_->get(id);
if (value->IsTheHole(isolate_)) return MaybeHandle<JSReceiver>();
DCHECK(value->IsJSReceiver());
return Handle<JSReceiver>(JSReceiver::cast(value), isolate_);
}
void ValueDeserializer::AddObjectWithID(uint32_t id,
Handle<JSReceiver> object) {
DCHECK(!HasObjectWithID(id));
Handle<FixedArray> new_array = FixedArray::SetAndGrow(id_map_, id, object);
// If the dictionary was reallocated, update the global handle.
if (!new_array.is_identical_to(id_map_)) {
GlobalHandles::Destroy(Handle<Object>::cast(id_map_).location());
id_map_ = Handle<FixedArray>::cast(
isolate_->global_handles()->Create(*new_array));
}
}
static Maybe<bool> SetPropertiesFromKeyValuePairs(Isolate* isolate,
Handle<JSObject> object,
Handle<Object>* data,
uint32_t num_properties) {
for (unsigned i = 0; i < 2 * num_properties; i += 2) {
Handle<Object> key = data[i];
Handle<Object> value = data[i + 1];
bool success;
LookupIterator it = LookupIterator::PropertyOrElement(
isolate, object, key, &success, LookupIterator::OWN);
if (!success ||
JSObject::DefineOwnPropertyIgnoreAttributes(&it, value, NONE)
.is_null()) {
return Nothing<bool>();
}
}
return Just(true);
}
MaybeHandle<Object>
ValueDeserializer::ReadObjectUsingEntireBufferForLegacyFormat() {
DCHECK_EQ(version_, 0);
HandleScope scope(isolate_);
std::vector<Handle<Object>> stack;
while (position_ < end_) {
SerializationTag tag;
if (!PeekTag().To(&tag)) break;
Handle<Object> new_object;
switch (tag) {
case SerializationTag::kEndJSObject: {
ConsumeTag(SerializationTag::kEndJSObject);
// JS Object: Read the last 2*n values from the stack and use them as
// key-value pairs.
uint32_t num_properties;
if (!ReadVarint<uint32_t>().To(&num_properties) ||
stack.size() / 2 < num_properties) {
return MaybeHandle<Object>();
}
size_t begin_properties =
stack.size() - 2 * static_cast<size_t>(num_properties);
Handle<JSObject> js_object = isolate_->factory()->NewJSObject(
isolate_->object_function(), pretenure_);
if (num_properties &&
!SetPropertiesFromKeyValuePairs(
isolate_, js_object, &stack[begin_properties], num_properties)
.FromMaybe(false)) {
return MaybeHandle<Object>();
}
stack.resize(begin_properties);
new_object = js_object;
break;
}
case SerializationTag::kEndSparseJSArray: {
ConsumeTag(SerializationTag::kEndSparseJSArray);
// Sparse JS Array: Read the last 2*|num_properties| from the stack.
uint32_t num_properties;
uint32_t length;
if (!ReadVarint<uint32_t>().To(&num_properties) ||
!ReadVarint<uint32_t>().To(&length) ||
stack.size() / 2 < num_properties) {
return MaybeHandle<Object>();
}
Handle<JSArray> js_array = isolate_->factory()->NewJSArray(
0, TERMINAL_FAST_ELEMENTS_KIND, pretenure_);
JSArray::SetLength(js_array, length);
size_t begin_properties =
stack.size() - 2 * static_cast<size_t>(num_properties);
if (num_properties &&
!SetPropertiesFromKeyValuePairs(
isolate_, js_array, &stack[begin_properties], num_properties)
.FromMaybe(false)) {
return MaybeHandle<Object>();
}
stack.resize(begin_properties);
new_object = js_array;
break;
}
case SerializationTag::kEndDenseJSArray: {
// This was already broken in Chromium, and apparently wasn't missed.
isolate_->Throw(*isolate_->factory()->NewError(
MessageTemplate::kDataCloneDeserializationError));
return MaybeHandle<Object>();
}
default:
if (!ReadObject().ToHandle(&new_object)) return MaybeHandle<Object>();
break;
}
stack.push_back(new_object);
}
// Nothing remains but padding.
#ifdef DEBUG
while (position_ < end_) {
DCHECK(*position_++ == static_cast<uint8_t>(SerializationTag::kPadding));
}
#endif
position_ = end_;
if (stack.size() != 1) {
isolate_->Throw(*isolate_->factory()->NewError(
MessageTemplate::kDataCloneDeserializationError));
return MaybeHandle<Object>();
}
return scope.CloseAndEscape(stack[0]);
}
} // namespace internal
} // namespace v8
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