blob: 13f65705a33d58f07e5416d04ab04c200c201924 [file] [log] [blame]
// 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/json-parser.h"
#include "src/char-predicates-inl.h"
#include "src/conversions.h"
#include "src/debug/debug.h"
#include "src/factory.h"
#include "src/field-type.h"
#include "src/messages.h"
#include "src/objects-inl.h"
#include "src/property-descriptor.h"
#include "src/string-hasher.h"
#include "src/transitions.h"
#include "src/unicode-cache.h"
#include "src/zone/zone-containers.h"
namespace v8 {
namespace internal {
MaybeHandle<Object> JsonParseInternalizer::Internalize(Isolate* isolate,
Handle<Object> object,
Handle<Object> reviver) {
DCHECK(reviver->IsCallable());
JsonParseInternalizer internalizer(isolate,
Handle<JSReceiver>::cast(reviver));
Handle<JSObject> holder =
isolate->factory()->NewJSObject(isolate->object_function());
Handle<String> name = isolate->factory()->empty_string();
JSObject::AddProperty(holder, name, object, NONE);
return internalizer.InternalizeJsonProperty(holder, name);
}
MaybeHandle<Object> JsonParseInternalizer::InternalizeJsonProperty(
Handle<JSReceiver> holder, Handle<String> name) {
HandleScope outer_scope(isolate_);
Handle<Object> value;
ASSIGN_RETURN_ON_EXCEPTION(
isolate_, value, Object::GetPropertyOrElement(holder, name), Object);
if (value->IsJSReceiver()) {
Handle<JSReceiver> object = Handle<JSReceiver>::cast(value);
Maybe<bool> is_array = Object::IsArray(object);
if (is_array.IsNothing()) return MaybeHandle<Object>();
if (is_array.FromJust()) {
Handle<Object> length_object;
ASSIGN_RETURN_ON_EXCEPTION(
isolate_, length_object,
Object::GetLengthFromArrayLike(isolate_, object), Object);
double length = length_object->Number();
for (double i = 0; i < length; i++) {
HandleScope inner_scope(isolate_);
Handle<Object> index = isolate_->factory()->NewNumber(i);
Handle<String> name = isolate_->factory()->NumberToString(index);
if (!RecurseAndApply(object, name)) return MaybeHandle<Object>();
}
} else {
Handle<FixedArray> contents;
ASSIGN_RETURN_ON_EXCEPTION(
isolate_, contents,
KeyAccumulator::GetKeys(object, KeyCollectionMode::kOwnOnly,
ENUMERABLE_STRINGS,
GetKeysConversion::kConvertToString),
Object);
for (int i = 0; i < contents->length(); i++) {
HandleScope inner_scope(isolate_);
Handle<String> name(String::cast(contents->get(i)), isolate_);
if (!RecurseAndApply(object, name)) return MaybeHandle<Object>();
}
}
}
Handle<Object> argv[] = {name, value};
Handle<Object> result;
ASSIGN_RETURN_ON_EXCEPTION(
isolate_, result, Execution::Call(isolate_, reviver_, holder, 2, argv),
Object);
return outer_scope.CloseAndEscape(result);
}
bool JsonParseInternalizer::RecurseAndApply(Handle<JSReceiver> holder,
Handle<String> name) {
STACK_CHECK(isolate_, false);
Handle<Object> result;
ASSIGN_RETURN_ON_EXCEPTION_VALUE(
isolate_, result, InternalizeJsonProperty(holder, name), false);
Maybe<bool> change_result = Nothing<bool>();
if (result->IsUndefined(isolate_)) {
change_result = JSReceiver::DeletePropertyOrElement(holder, name,
LanguageMode::kSloppy);
} else {
PropertyDescriptor desc;
desc.set_value(result);
desc.set_configurable(true);
desc.set_enumerable(true);
desc.set_writable(true);
change_result = JSReceiver::DefineOwnProperty(isolate_, holder, name, &desc,
kDontThrow);
}
MAYBE_RETURN(change_result, false);
return true;
}
template <bool seq_one_byte>
JsonParser<seq_one_byte>::JsonParser(Isolate* isolate, Handle<String> source)
: source_(source),
source_length_(source->length()),
isolate_(isolate),
factory_(isolate_->factory()),
zone_(isolate_->allocator(), ZONE_NAME),
object_constructor_(isolate_->native_context()->object_function(),
isolate_),
position_(-1) {
source_ = String::Flatten(source_);
pretenure_ = (source_length_ >= kPretenureTreshold) ? TENURED : NOT_TENURED;
// Optimized fast case where we only have Latin1 characters.
if (seq_one_byte) {
seq_source_ = Handle<SeqOneByteString>::cast(source_);
}
}
template <bool seq_one_byte>
MaybeHandle<Object> JsonParser<seq_one_byte>::ParseJson() {
// Advance to the first character (possibly EOS)
AdvanceSkipWhitespace();
Handle<Object> result = ParseJsonValue();
if (result.is_null() || c0_ != kEndOfString) {
// Some exception (for example stack overflow) is already pending.
if (isolate_->has_pending_exception()) return Handle<Object>::null();
// Parse failed. Current character is the unexpected token.
Factory* factory = this->factory();
MessageTemplate::Template message;
Handle<Object> arg1 = Handle<Smi>(Smi::FromInt(position_), isolate());
Handle<Object> arg2;
switch (c0_) {
case kEndOfString:
message = MessageTemplate::kJsonParseUnexpectedEOS;
break;
case '-':
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
message = MessageTemplate::kJsonParseUnexpectedTokenNumber;
break;
case '"':
message = MessageTemplate::kJsonParseUnexpectedTokenString;
break;
default:
message = MessageTemplate::kJsonParseUnexpectedToken;
arg2 = arg1;
arg1 = factory->LookupSingleCharacterStringFromCode(c0_);
break;
}
Handle<Script> script(factory->NewScript(source_));
// We should sent compile error event because we compile JSON object in
// separated source file.
isolate()->debug()->OnCompileError(script);
MessageLocation location(script, position_, position_ + 1);
Handle<Object> error = factory->NewSyntaxError(message, arg1, arg2);
return isolate()->template Throw<Object>(error, &location);
}
return result;
}
MaybeHandle<Object> InternalizeJsonProperty(Handle<JSObject> holder,
Handle<String> key);
template <bool seq_one_byte>
void JsonParser<seq_one_byte>::Advance() {
position_++;
if (position_ >= source_length_) {
c0_ = kEndOfString;
} else if (seq_one_byte) {
c0_ = seq_source_->SeqOneByteStringGet(position_);
} else {
c0_ = source_->Get(position_);
}
}
template <bool seq_one_byte>
void JsonParser<seq_one_byte>::AdvanceSkipWhitespace() {
do {
Advance();
} while (c0_ == ' ' || c0_ == '\t' || c0_ == '\n' || c0_ == '\r');
}
template <bool seq_one_byte>
void JsonParser<seq_one_byte>::SkipWhitespace() {
while (c0_ == ' ' || c0_ == '\t' || c0_ == '\n' || c0_ == '\r') {
Advance();
}
}
template <bool seq_one_byte>
uc32 JsonParser<seq_one_byte>::AdvanceGetChar() {
Advance();
return c0_;
}
template <bool seq_one_byte>
bool JsonParser<seq_one_byte>::MatchSkipWhiteSpace(uc32 c) {
if (c0_ == c) {
AdvanceSkipWhitespace();
return true;
}
return false;
}
template <bool seq_one_byte>
bool JsonParser<seq_one_byte>::ParseJsonString(Handle<String> expected) {
int length = expected->length();
if (source_->length() - position_ - 1 > length) {
DisallowHeapAllocation no_gc;
String::FlatContent content = expected->GetFlatContent();
if (content.IsOneByte()) {
DCHECK_EQ('"', c0_);
const uint8_t* input_chars = seq_source_->GetChars() + position_ + 1;
const uint8_t* expected_chars = content.ToOneByteVector().start();
for (int i = 0; i < length; i++) {
uint8_t c0 = input_chars[i];
if (c0 != expected_chars[i] || c0 == '"' || c0 < 0x20 || c0 == '\\') {
return false;
}
}
if (input_chars[length] == '"') {
position_ = position_ + length + 1;
AdvanceSkipWhitespace();
return true;
}
}
}
return false;
}
// Parse any JSON value.
template <bool seq_one_byte>
Handle<Object> JsonParser<seq_one_byte>::ParseJsonValue() {
StackLimitCheck stack_check(isolate_);
if (stack_check.HasOverflowed()) {
isolate_->StackOverflow();
return Handle<Object>::null();
}
if (stack_check.InterruptRequested() &&
isolate_->stack_guard()->HandleInterrupts()->IsException(isolate_)) {
return Handle<Object>::null();
}
if (c0_ == '"') return ParseJsonString();
if ((c0_ >= '0' && c0_ <= '9') || c0_ == '-') return ParseJsonNumber();
if (c0_ == '{') return ParseJsonObject();
if (c0_ == '[') return ParseJsonArray();
if (c0_ == 'f') {
if (AdvanceGetChar() == 'a' && AdvanceGetChar() == 'l' &&
AdvanceGetChar() == 's' && AdvanceGetChar() == 'e') {
AdvanceSkipWhitespace();
return factory()->false_value();
}
return ReportUnexpectedCharacter();
}
if (c0_ == 't') {
if (AdvanceGetChar() == 'r' && AdvanceGetChar() == 'u' &&
AdvanceGetChar() == 'e') {
AdvanceSkipWhitespace();
return factory()->true_value();
}
return ReportUnexpectedCharacter();
}
if (c0_ == 'n') {
if (AdvanceGetChar() == 'u' && AdvanceGetChar() == 'l' &&
AdvanceGetChar() == 'l') {
AdvanceSkipWhitespace();
return factory()->null_value();
}
return ReportUnexpectedCharacter();
}
return ReportUnexpectedCharacter();
}
template <bool seq_one_byte>
ParseElementResult JsonParser<seq_one_byte>::ParseElement(
Handle<JSObject> json_object) {
uint32_t index = 0;
// Maybe an array index, try to parse it.
if (c0_ == '0') {
// With a leading zero, the string has to be "0" only to be an index.
Advance();
} else {
do {
int d = c0_ - '0';
if (index > 429496729U - ((d + 3) >> 3)) break;
index = (index * 10) + d;
Advance();
} while (IsDecimalDigit(c0_));
}
if (c0_ == '"') {
// Successfully parsed index, parse and store element.
AdvanceSkipWhitespace();
if (c0_ == ':') {
AdvanceSkipWhitespace();
Handle<Object> value = ParseJsonValue();
if (!value.is_null()) {
JSObject::SetOwnElementIgnoreAttributes(json_object, index, value, NONE)
.Assert();
return kElementFound;
} else {
return kNullHandle;
}
}
}
return kElementNotFound;
}
// Parse a JSON object. Position must be right at '{'.
template <bool seq_one_byte>
Handle<Object> JsonParser<seq_one_byte>::ParseJsonObject() {
HandleScope scope(isolate());
Handle<JSObject> json_object =
factory()->NewJSObject(object_constructor(), pretenure_);
Handle<Map> map(json_object->map());
int descriptor = 0;
ZoneVector<Handle<Object>> properties(zone());
DCHECK_EQ(c0_, '{');
bool transitioning = true;
AdvanceSkipWhitespace();
if (c0_ != '}') {
do {
if (c0_ != '"') return ReportUnexpectedCharacter();
int start_position = position_;
Advance();
if (IsDecimalDigit(c0_)) {
ParseElementResult element_result = ParseElement(json_object);
if (element_result == kNullHandle) return Handle<Object>::null();
if (element_result == kElementFound) continue;
}
// Not an index, fallback to the slow path.
position_ = start_position;
#ifdef DEBUG
c0_ = '"';
#endif
Handle<String> key;
Handle<Object> value;
// Try to follow existing transitions as long as possible. Once we stop
// transitioning, no transition can be found anymore.
DCHECK(transitioning);
// First check whether there is a single expected transition. If so, try
// to parse it first.
bool follow_expected = false;
Handle<Map> target;
if (seq_one_byte) {
DisallowHeapAllocation no_gc;
TransitionsAccessor transitions(*map, &no_gc);
key = transitions.ExpectedTransitionKey();
follow_expected = !key.is_null() && ParseJsonString(key);
// If the expected transition hits, follow it.
if (follow_expected) {
target = transitions.ExpectedTransitionTarget();
}
}
if (!follow_expected) {
// If the expected transition failed, parse an internalized string and
// try to find a matching transition.
key = ParseJsonInternalizedString();
if (key.is_null()) return ReportUnexpectedCharacter();
target = TransitionsAccessor(map).FindTransitionToField(key);
// If a transition was found, follow it and continue.
transitioning = !target.is_null();
}
if (c0_ != ':') return ReportUnexpectedCharacter();
AdvanceSkipWhitespace();
value = ParseJsonValue();
if (value.is_null()) return ReportUnexpectedCharacter();
if (transitioning) {
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::GeneralizeField(target, descriptor, details.constness(),
expected_representation, value_type);
}
DCHECK(target->instance_descriptors()
->GetFieldType(descriptor)
->NowContains(value));
properties.push_back(value);
map = target;
descriptor++;
continue;
} else {
transitioning = false;
}
}
DCHECK(!transitioning);
// Commit the intermediate state to the object and stop transitioning.
CommitStateToJsonObject(json_object, map, &properties);
JSObject::DefinePropertyOrElementIgnoreAttributes(json_object, key, value)
.Check();
} while (transitioning && MatchSkipWhiteSpace(','));
// If we transitioned until the very end, transition the map now.
if (transitioning) {
CommitStateToJsonObject(json_object, map, &properties);
} else {
while (MatchSkipWhiteSpace(',')) {
HandleScope local_scope(isolate());
if (c0_ != '"') return ReportUnexpectedCharacter();
int start_position = position_;
Advance();
if (IsDecimalDigit(c0_)) {
ParseElementResult element_result = ParseElement(json_object);
if (element_result == kNullHandle) return Handle<Object>::null();
if (element_result == kElementFound) continue;
}
// Not an index, fallback to the slow path.
position_ = start_position;
#ifdef DEBUG
c0_ = '"';
#endif
Handle<String> key;
Handle<Object> value;
key = ParseJsonInternalizedString();
if (key.is_null() || c0_ != ':') return ReportUnexpectedCharacter();
AdvanceSkipWhitespace();
value = ParseJsonValue();
if (value.is_null()) return ReportUnexpectedCharacter();
JSObject::DefinePropertyOrElementIgnoreAttributes(json_object, key,
value)
.Check();
}
}
if (c0_ != '}') {
return ReportUnexpectedCharacter();
}
}
AdvanceSkipWhitespace();
return scope.CloseAndEscape(json_object);
}
template <bool seq_one_byte>
void JsonParser<seq_one_byte>::CommitStateToJsonObject(
Handle<JSObject> json_object, Handle<Map> map,
ZoneVector<Handle<Object>>* properties) {
JSObject::AllocateStorageForMap(json_object, map);
DCHECK(!json_object->map()->is_dictionary_map());
DisallowHeapAllocation no_gc;
DescriptorArray* descriptors = json_object->map()->instance_descriptors();
int length = static_cast<int>(properties->size());
for (int i = 0; i < length; i++) {
Handle<Object> value = (*properties)[i];
// Initializing store.
json_object->WriteToField(i, descriptors->GetDetails(i), *value);
}
}
class ElementKindLattice {
private:
enum {
SMI_ELEMENTS,
NUMBER_ELEMENTS,
OBJECT_ELEMENTS,
};
public:
ElementKindLattice() : value_(SMI_ELEMENTS) {}
void Update(Handle<Object> o) {
if (o->IsSmi()) {
return;
} else if (o->IsHeapNumber()) {
if (value_ < NUMBER_ELEMENTS) value_ = NUMBER_ELEMENTS;
} else {
DCHECK(!o->IsNumber());
value_ = OBJECT_ELEMENTS;
}
}
ElementsKind GetElementsKind() const {
switch (value_) {
case SMI_ELEMENTS:
return PACKED_SMI_ELEMENTS;
case NUMBER_ELEMENTS:
return PACKED_DOUBLE_ELEMENTS;
case OBJECT_ELEMENTS:
return PACKED_ELEMENTS;
default:
UNREACHABLE();
return PACKED_ELEMENTS;
}
}
private:
int value_;
};
// Parse a JSON array. Position must be right at '['.
template <bool seq_one_byte>
Handle<Object> JsonParser<seq_one_byte>::ParseJsonArray() {
HandleScope scope(isolate());
ZoneVector<Handle<Object>> elements(zone());
DCHECK_EQ(c0_, '[');
ElementKindLattice lattice;
AdvanceSkipWhitespace();
if (c0_ != ']') {
do {
Handle<Object> element = ParseJsonValue();
if (element.is_null()) return ReportUnexpectedCharacter();
elements.push_back(element);
lattice.Update(element);
} while (MatchSkipWhiteSpace(','));
if (c0_ != ']') {
return ReportUnexpectedCharacter();
}
}
AdvanceSkipWhitespace();
// Allocate a fixed array with all the elements.
Handle<Object> json_array;
const ElementsKind kind = lattice.GetElementsKind();
int elements_size = static_cast<int>(elements.size());
switch (kind) {
case PACKED_ELEMENTS:
case PACKED_SMI_ELEMENTS: {
Handle<FixedArray> elems =
factory()->NewFixedArray(elements_size, pretenure_);
for (int i = 0; i < elements_size; i++) elems->set(i, *elements[i]);
json_array = factory()->NewJSArrayWithElements(elems, kind, pretenure_);
break;
}
case PACKED_DOUBLE_ELEMENTS: {
Handle<FixedDoubleArray> elems = Handle<FixedDoubleArray>::cast(
factory()->NewFixedDoubleArray(elements_size, pretenure_));
for (int i = 0; i < elements_size; i++) {
elems->set(i, elements[i]->Number());
}
json_array = factory()->NewJSArrayWithElements(elems, kind, pretenure_);
break;
}
default:
UNREACHABLE();
}
return scope.CloseAndEscape(json_array);
}
template <bool seq_one_byte>
Handle<Object> JsonParser<seq_one_byte>::ParseJsonNumber() {
bool negative = false;
int beg_pos = position_;
if (c0_ == '-') {
Advance();
negative = true;
}
if (c0_ == '0') {
Advance();
// Prefix zero is only allowed if it's the only digit before
// a decimal point or exponent.
if (IsDecimalDigit(c0_)) return ReportUnexpectedCharacter();
} else {
int i = 0;
int digits = 0;
if (c0_ < '1' || c0_ > '9') return ReportUnexpectedCharacter();
do {
i = i * 10 + c0_ - '0';
digits++;
Advance();
} while (IsDecimalDigit(c0_));
if (c0_ != '.' && c0_ != 'e' && c0_ != 'E' && digits < 10) {
SkipWhitespace();
return Handle<Smi>(Smi::FromInt((negative ? -i : i)), isolate());
}
}
if (c0_ == '.') {
Advance();
if (!IsDecimalDigit(c0_)) return ReportUnexpectedCharacter();
do {
Advance();
} while (IsDecimalDigit(c0_));
}
if (AsciiAlphaToLower(c0_) == 'e') {
Advance();
if (c0_ == '-' || c0_ == '+') Advance();
if (!IsDecimalDigit(c0_)) return ReportUnexpectedCharacter();
do {
Advance();
} while (IsDecimalDigit(c0_));
}
int length = position_ - beg_pos;
double number;
if (seq_one_byte) {
Vector<const uint8_t> chars(seq_source_->GetChars() + beg_pos, length);
number = StringToDouble(isolate()->unicode_cache(), chars,
NO_FLAGS, // Hex, octal or trailing junk.
std::numeric_limits<double>::quiet_NaN());
} else {
Vector<uint8_t> buffer = Vector<uint8_t>::New(length);
String::WriteToFlat(*source_, buffer.start(), beg_pos, position_);
Vector<const uint8_t> result =
Vector<const uint8_t>(buffer.start(), length);
number = StringToDouble(isolate()->unicode_cache(), result,
NO_FLAGS, // Hex, octal or trailing junk.
0.0);
buffer.Dispose();
}
SkipWhitespace();
return factory()->NewNumber(number, pretenure_);
}
template <typename StringType>
inline void SeqStringSet(Handle<StringType> seq_str, int i, uc32 c);
template <>
inline void SeqStringSet(Handle<SeqTwoByteString> seq_str, int i, uc32 c) {
seq_str->SeqTwoByteStringSet(i, c);
}
template <>
inline void SeqStringSet(Handle<SeqOneByteString> seq_str, int i, uc32 c) {
seq_str->SeqOneByteStringSet(i, c);
}
template <typename StringType>
inline Handle<StringType> NewRawString(Factory* factory, int length,
PretenureFlag pretenure);
template <>
inline Handle<SeqTwoByteString> NewRawString(Factory* factory, int length,
PretenureFlag pretenure) {
return factory->NewRawTwoByteString(length, pretenure).ToHandleChecked();
}
template <>
inline Handle<SeqOneByteString> NewRawString(Factory* factory, int length,
PretenureFlag pretenure) {
return factory->NewRawOneByteString(length, pretenure).ToHandleChecked();
}
// Scans the rest of a JSON string starting from position_ and writes
// prefix[start..end] along with the scanned characters into a
// sequential string of type StringType.
template <bool seq_one_byte>
template <typename StringType, typename SinkChar>
Handle<String> JsonParser<seq_one_byte>::SlowScanJsonString(
Handle<String> prefix, int start, int end) {
int count = end - start;
int max_length = count + source_length_ - position_;
int length = Min(max_length, Max(kInitialSpecialStringLength, 2 * count));
Handle<StringType> seq_string =
NewRawString<StringType>(factory(), length, pretenure_);
// Copy prefix into seq_str.
SinkChar* dest = seq_string->GetChars();
String::WriteToFlat(*prefix, dest, start, end);
while (c0_ != '"') {
// Check for control character (0x00-0x1f) or unterminated string (<0).
if (c0_ < 0x20) return Handle<String>::null();
if (count >= length) {
// We need to create a longer sequential string for the result.
return SlowScanJsonString<StringType, SinkChar>(seq_string, 0, count);
}
if (c0_ != '\\') {
// If the sink can contain UC16 characters, or source_ contains only
// Latin1 characters, there's no need to test whether we can store the
// character. Otherwise check whether the UC16 source character can fit
// in the Latin1 sink.
if (sizeof(SinkChar) == kUC16Size || seq_one_byte ||
c0_ <= String::kMaxOneByteCharCode) {
SeqStringSet(seq_string, count++, c0_);
Advance();
} else {
// StringType is SeqOneByteString and we just read a non-Latin1 char.
return SlowScanJsonString<SeqTwoByteString, uc16>(seq_string, 0, count);
}
} else {
Advance(); // Advance past the \.
switch (c0_) {
case '"':
case '\\':
case '/':
SeqStringSet(seq_string, count++, c0_);
break;
case 'b':
SeqStringSet(seq_string, count++, '\x08');
break;
case 'f':
SeqStringSet(seq_string, count++, '\x0c');
break;
case 'n':
SeqStringSet(seq_string, count++, '\x0a');
break;
case 'r':
SeqStringSet(seq_string, count++, '\x0d');
break;
case 't':
SeqStringSet(seq_string, count++, '\x09');
break;
case 'u': {
uc32 value = 0;
for (int i = 0; i < 4; i++) {
Advance();
int digit = HexValue(c0_);
if (digit < 0) {
return Handle<String>::null();
}
value = value * 16 + digit;
}
if (sizeof(SinkChar) == kUC16Size ||
value <= String::kMaxOneByteCharCode) {
SeqStringSet(seq_string, count++, value);
break;
} else {
// StringType is SeqOneByteString and we just read a non-Latin1
// char.
position_ -= 6; // Rewind position_ to \ in \uxxxx.
Advance();
return SlowScanJsonString<SeqTwoByteString, uc16>(seq_string, 0,
count);
}
}
default:
return Handle<String>::null();
}
Advance();
}
}
DCHECK_EQ('"', c0_);
// Advance past the last '"'.
AdvanceSkipWhitespace();
// Shrink seq_string length to count and return.
return SeqString::Truncate(seq_string, count);
}
template <bool seq_one_byte>
template <bool is_internalized>
Handle<String> JsonParser<seq_one_byte>::ScanJsonString() {
DCHECK_EQ('"', c0_);
Advance();
if (c0_ == '"') {
AdvanceSkipWhitespace();
return factory()->empty_string();
}
if (seq_one_byte && is_internalized) {
// Fast path for existing internalized strings. If the the string being
// parsed is not a known internalized string, contains backslashes or
// unexpectedly reaches the end of string, return with an empty handle.
// We intentionally use local variables instead of fields, compute hash
// while we are iterating a string and manually inline StringTable lookup
// here.
uint32_t running_hash = isolate()->heap()->HashSeed();
int position = position_;
uc32 c0 = c0_;
do {
if (c0 == '\\') {
c0_ = c0;
int beg_pos = position_;
position_ = position;
return SlowScanJsonString<SeqOneByteString, uint8_t>(source_, beg_pos,
position_);
}
if (c0 < 0x20) {
c0_ = c0;
position_ = position;
return Handle<String>::null();
}
running_hash = StringHasher::AddCharacterCore(running_hash,
static_cast<uint16_t>(c0));
position++;
if (position >= source_length_) {
c0_ = kEndOfString;
position_ = position;
return Handle<String>::null();
}
c0 = seq_source_->SeqOneByteStringGet(position);
} while (c0 != '"');
int length = position - position_;
uint32_t hash = (length <= String::kMaxHashCalcLength)
? StringHasher::GetHashCore(running_hash)
: static_cast<uint32_t>(length);
Vector<const uint8_t> string_vector(seq_source_->GetChars() + position_,
length);
StringTable* string_table = isolate()->heap()->string_table();
uint32_t capacity = string_table->Capacity();
uint32_t entry = StringTable::FirstProbe(hash, capacity);
uint32_t count = 1;
Handle<String> result;
while (true) {
Object* element = string_table->KeyAt(entry);
if (element->IsUndefined(isolate())) {
// Lookup failure.
result =
factory()->InternalizeOneByteString(seq_source_, position_, length);
break;
}
if (!element->IsTheHole(isolate()) &&
String::cast(element)->IsOneByteEqualTo(string_vector)) {
result = Handle<String>(String::cast(element), isolate());
#ifdef DEBUG
uint32_t hash_field =
(hash << String::kHashShift) | String::kIsNotArrayIndexMask;
DCHECK_EQ(static_cast<int>(result->Hash()),
static_cast<int>(hash_field >> String::kHashShift));
#endif
break;
}
entry = StringTable::NextProbe(entry, count++, capacity);
}
position_ = position;
// Advance past the last '"'.
AdvanceSkipWhitespace();
return result;
}
int beg_pos = position_;
// Fast case for Latin1 only without escape characters.
do {
// Check for control character (0x00-0x1f) or unterminated string (<0).
if (c0_ < 0x20) return Handle<String>::null();
if (c0_ != '\\') {
if (seq_one_byte || c0_ <= String::kMaxOneByteCharCode) {
Advance();
} else {
return SlowScanJsonString<SeqTwoByteString, uc16>(source_, beg_pos,
position_);
}
} else {
return SlowScanJsonString<SeqOneByteString, uint8_t>(source_, beg_pos,
position_);
}
} while (c0_ != '"');
int length = position_ - beg_pos;
Handle<String> result =
factory()->NewRawOneByteString(length, pretenure_).ToHandleChecked();
uint8_t* dest = SeqOneByteString::cast(*result)->GetChars();
String::WriteToFlat(*source_, dest, beg_pos, position_);
DCHECK_EQ('"', c0_);
// Advance past the last '"'.
AdvanceSkipWhitespace();
return result;
}
// Explicit instantiation.
template class JsonParser<true>;
template class JsonParser<false>;
} // namespace internal
} // namespace v8