// 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-stringifier.h"
#include "src/conversions.h"
#include "src/lookup.h"
#include "src/messages.h"
#include "src/objects-inl.h"
#include "src/utils.h"
namespace v8 {
namespace internal {
// Translation table to escape Latin1 characters.
// Table entries start at a multiple of 8 and are null-terminated.
const char* const JsonStringifier::JsonEscapeTable =
"\\u0000\0 \\u0001\0 \\u0002\0 \\u0003\0 "
"\\u0004\0 \\u0005\0 \\u0006\0 \\u0007\0 "
"\\b\0 \\t\0 \\n\0 \\u000b\0 "
"\\f\0 \\r\0 \\u000e\0 \\u000f\0 "
"\\u0010\0 \\u0011\0 \\u0012\0 \\u0013\0 "
"\\u0014\0 \\u0015\0 \\u0016\0 \\u0017\0 "
"\\u0018\0 \\u0019\0 \\u001a\0 \\u001b\0 "
"\\u001c\0 \\u001d\0 \\u001e\0 \\u001f\0 "
" \0 !\0 \\\"\0 #\0 "
"$\0 %\0 &\0 '\0 "
"(\0 )\0 *\0 +\0 "
",\0 -\0 .\0 /\0 "
"0\0 1\0 2\0 3\0 "
"4\0 5\0 6\0 7\0 "
"8\0 9\0 :\0 ;\0 "
"<\0 =\0 >\0 ?\0 "
"@\0 A\0 B\0 C\0 "
"D\0 E\0 F\0 G\0 "
"H\0 I\0 J\0 K\0 "
"L\0 M\0 N\0 O\0 "
"P\0 Q\0 R\0 S\0 "
"T\0 U\0 V\0 W\0 "
"X\0 Y\0 Z\0 [\0 "
"\\\\\0 ]\0 ^\0 _\0 "
"`\0 a\0 b\0 c\0 "
"d\0 e\0 f\0 g\0 "
"h\0 i\0 j\0 k\0 "
"l\0 m\0 n\0 o\0 "
"p\0 q\0 r\0 s\0 "
"t\0 u\0 v\0 w\0 "
"x\0 y\0 z\0 {\0 "
"|\0 }\0 ~\0 \177\0 "
"\200\0 \201\0 \202\0 \203\0 "
"\204\0 \205\0 \206\0 \207\0 "
"\210\0 \211\0 \212\0 \213\0 "
"\214\0 \215\0 \216\0 \217\0 "
"\220\0 \221\0 \222\0 \223\0 "
"\224\0 \225\0 \226\0 \227\0 "
"\230\0 \231\0 \232\0 \233\0 "
"\234\0 \235\0 \236\0 \237\0 "
"\240\0 \241\0 \242\0 \243\0 "
"\244\0 \245\0 \246\0 \247\0 "
"\250\0 \251\0 \252\0 \253\0 "
"\254\0 \255\0 \256\0 \257\0 "
"\260\0 \261\0 \262\0 \263\0 "
"\264\0 \265\0 \266\0 \267\0 "
"\270\0 \271\0 \272\0 \273\0 "
"\274\0 \275\0 \276\0 \277\0 "
"\300\0 \301\0 \302\0 \303\0 "
"\304\0 \305\0 \306\0 \307\0 "
"\310\0 \311\0 \312\0 \313\0 "
"\314\0 \315\0 \316\0 \317\0 "
"\320\0 \321\0 \322\0 \323\0 "
"\324\0 \325\0 \326\0 \327\0 "
"\330\0 \331\0 \332\0 \333\0 "
"\334\0 \335\0 \336\0 \337\0 "
"\340\0 \341\0 \342\0 \343\0 "
"\344\0 \345\0 \346\0 \347\0 "
"\350\0 \351\0 \352\0 \353\0 "
"\354\0 \355\0 \356\0 \357\0 "
"\360\0 \361\0 \362\0 \363\0 "
"\364\0 \365\0 \366\0 \367\0 "
"\370\0 \371\0 \372\0 \373\0 "
"\374\0 \375\0 \376\0 \377\0 ";
JsonStringifier::JsonStringifier(Isolate* isolate)
: isolate_(isolate), builder_(isolate), gap_(nullptr), indent_(0) {
tojson_string_ = factory()->toJSON_string();
stack_ = factory()->NewJSArray(8);
}
MaybeHandle<Object> JsonStringifier::Stringify(Handle<Object> object,
Handle<Object> replacer,
Handle<Object> gap) {
if (!InitializeReplacer(replacer)) return MaybeHandle<Object>();
if (!gap->IsUndefined(isolate_) && !InitializeGap(gap)) {
return MaybeHandle<Object>();
}
Result result = SerializeObject(object);
if (result == UNCHANGED) return factory()->undefined_value();
if (result == SUCCESS) return builder_.Finish();
DCHECK(result == EXCEPTION);
return MaybeHandle<Object>();
}
bool IsInList(Handle<String> key, List<Handle<String> >* list) {
// TODO(yangguo): This is O(n^2) for n properties in the list. Deal with this
// if this becomes an issue.
for (const Handle<String>& existing : *list) {
if (String::Equals(existing, key)) return true;
}
return false;
}
bool JsonStringifier::InitializeReplacer(Handle<Object> replacer) {
DCHECK(property_list_.is_null());
DCHECK(replacer_function_.is_null());
Maybe<bool> is_array = Object::IsArray(replacer);
if (is_array.IsNothing()) return false;
if (is_array.FromJust()) {
HandleScope handle_scope(isolate_);
List<Handle<String> > list;
Handle<Object> length_obj;
ASSIGN_RETURN_ON_EXCEPTION_VALUE(
isolate_, length_obj,
Object::GetLengthFromArrayLike(isolate_, replacer), false);
uint32_t length;
if (!length_obj->ToUint32(&length)) length = kMaxUInt32;
for (uint32_t i = 0; i < length; i++) {
Handle<Object> element;
Handle<String> key;
ASSIGN_RETURN_ON_EXCEPTION_VALUE(
isolate_, element, Object::GetElement(isolate_, replacer, i), false);
if (element->IsNumber() || element->IsString()) {
ASSIGN_RETURN_ON_EXCEPTION_VALUE(
isolate_, key, Object::ToString(isolate_, element), false);
} else if (element->IsJSValue()) {
Handle<Object> value(Handle<JSValue>::cast(element)->value(), isolate_);
if (value->IsNumber() || value->IsString()) {
ASSIGN_RETURN_ON_EXCEPTION_VALUE(
isolate_, key, Object::ToString(isolate_, element), false);
}
}
if (key.is_null()) continue;
if (!IsInList(key, &list)) list.Add(key);
}
property_list_ = factory()->NewUninitializedFixedArray(list.length());
for (int i = 0; i < list.length(); i++) {
property_list_->set(i, *list[i]);
}
property_list_ = handle_scope.CloseAndEscape(property_list_);
} else if (replacer->IsCallable()) {
replacer_function_ = Handle<JSReceiver>::cast(replacer);
}
return true;
}
bool JsonStringifier::InitializeGap(Handle<Object> gap) {
DCHECK_NULL(gap_);
HandleScope scope(isolate_);
if (gap->IsJSValue()) {
Handle<Object> value(Handle<JSValue>::cast(gap)->value(), isolate_);
if (value->IsString()) {
ASSIGN_RETURN_ON_EXCEPTION_VALUE(isolate_, gap,
Object::ToString(isolate_, gap), false);
} else if (value->IsNumber()) {
ASSIGN_RETURN_ON_EXCEPTION_VALUE(isolate_, gap, Object::ToNumber(gap),
false);
}
}
if (gap->IsString()) {
Handle<String> gap_string = Handle<String>::cast(gap);
if (gap_string->length() > 0) {
int gap_length = std::min(gap_string->length(), 10);
gap_ = NewArray<uc16>(gap_length + 1);
String::WriteToFlat(*gap_string, gap_, 0, gap_length);
for (int i = 0; i < gap_length; i++) {
if (gap_[i] > String::kMaxOneByteCharCode) {
builder_.ChangeEncoding();
break;
}
}
gap_[gap_length] = '\0';
}
} else if (gap->IsNumber()) {
int num_value = DoubleToInt32(gap->Number());
if (num_value > 0) {
int gap_length = std::min(num_value, 10);
gap_ = NewArray<uc16>(gap_length + 1);
for (int i = 0; i < gap_length; i++) gap_[i] = ' ';
gap_[gap_length] = '\0';
}
}
return true;
}
MaybeHandle<Object> JsonStringifier::ApplyToJsonFunction(Handle<Object> object,
Handle<Object> key) {
HandleScope scope(isolate_);
LookupIterator it(object, tojson_string_,
LookupIterator::PROTOTYPE_CHAIN_SKIP_INTERCEPTOR);
Handle<Object> fun;
ASSIGN_RETURN_ON_EXCEPTION(isolate_, fun, Object::GetProperty(&it), Object);
if (!fun->IsCallable()) return object;
// Call toJSON function.
if (key->IsSmi()) key = factory()->NumberToString(key);
Handle<Object> argv[] = {key};
ASSIGN_RETURN_ON_EXCEPTION(isolate_, object,
Execution::Call(isolate_, fun, object, 1, argv),
Object);
return scope.CloseAndEscape(object);
}
MaybeHandle<Object> JsonStringifier::ApplyReplacerFunction(
Handle<Object> value, Handle<Object> key, Handle<Object> initial_holder) {
HandleScope scope(isolate_);
if (key->IsSmi()) key = factory()->NumberToString(key);
Handle<Object> argv[] = {key, value};
Handle<JSReceiver> holder = CurrentHolder(value, initial_holder);
ASSIGN_RETURN_ON_EXCEPTION(
isolate_, value,
Execution::Call(isolate_, replacer_function_, holder, 2, argv), Object);
return scope.CloseAndEscape(value);
}
Handle<JSReceiver> JsonStringifier::CurrentHolder(
Handle<Object> value, Handle<Object> initial_holder) {
int length = Smi::cast(stack_->length())->value();
if (length == 0) {
Handle<JSObject> holder =
factory()->NewJSObject(isolate_->object_function());
JSObject::AddProperty(holder, factory()->empty_string(), initial_holder,
NONE);
return holder;
} else {
FixedArray* elements = FixedArray::cast(stack_->elements());
return Handle<JSReceiver>(JSReceiver::cast(elements->get(length - 1)),
isolate_);
}
}
JsonStringifier::Result JsonStringifier::StackPush(Handle<Object> object) {
StackLimitCheck check(isolate_);
if (check.HasOverflowed()) {
isolate_->StackOverflow();
return EXCEPTION;
}
int length = Smi::cast(stack_->length())->value();
{
DisallowHeapAllocation no_allocation;
FixedArray* elements = FixedArray::cast(stack_->elements());
for (int i = 0; i < length; i++) {
if (elements->get(i) == *object) {
AllowHeapAllocation allow_to_return_error;
Handle<Object> error =
factory()->NewTypeError(MessageTemplate::kCircularStructure);
isolate_->Throw(*error);
return EXCEPTION;
}
}
}
JSArray::SetLength(stack_, length + 1);
FixedArray::cast(stack_->elements())->set(length, *object);
return SUCCESS;
}
void JsonStringifier::StackPop() {
int length = Smi::cast(stack_->length())->value();
stack_->set_length(Smi::FromInt(length - 1));
}
template <bool deferred_string_key>
JsonStringifier::Result JsonStringifier::Serialize_(Handle<Object> object,
bool comma,
Handle<Object> key) {
StackLimitCheck interrupt_check(isolate_);
Handle<Object> initial_value = object;
if (interrupt_check.InterruptRequested() &&
isolate_->stack_guard()->HandleInterrupts()->IsException(isolate_)) {
return EXCEPTION;
}
if (object->IsJSReceiver()) {
ASSIGN_RETURN_ON_EXCEPTION_VALUE(
isolate_, object, ApplyToJsonFunction(object, key), EXCEPTION);
}
if (!replacer_function_.is_null()) {
ASSIGN_RETURN_ON_EXCEPTION_VALUE(
isolate_, object, ApplyReplacerFunction(object, key, initial_value),
EXCEPTION);
}
if (object->IsSmi()) {
if (deferred_string_key) SerializeDeferredKey(comma, key);
return SerializeSmi(Smi::cast(*object));
}
switch (HeapObject::cast(*object)->map()->instance_type()) {
case HEAP_NUMBER_TYPE:
case MUTABLE_HEAP_NUMBER_TYPE:
if (deferred_string_key) SerializeDeferredKey(comma, key);
return SerializeHeapNumber(Handle<HeapNumber>::cast(object));
case ODDBALL_TYPE:
switch (Oddball::cast(*object)->kind()) {
case Oddball::kFalse:
if (deferred_string_key) SerializeDeferredKey(comma, key);
builder_.AppendCString("false");
return SUCCESS;
case Oddball::kTrue:
if (deferred_string_key) SerializeDeferredKey(comma, key);
builder_.AppendCString("true");
return SUCCESS;
case Oddball::kNull:
if (deferred_string_key) SerializeDeferredKey(comma, key);
builder_.AppendCString("null");
return SUCCESS;
default:
return UNCHANGED;
}
case JS_ARRAY_TYPE:
if (deferred_string_key) SerializeDeferredKey(comma, key);
return SerializeJSArray(Handle<JSArray>::cast(object));
case JS_VALUE_TYPE:
if (deferred_string_key) SerializeDeferredKey(comma, key);
return SerializeJSValue(Handle<JSValue>::cast(object));
case SYMBOL_TYPE:
return UNCHANGED;
default:
if (object->IsString()) {
if (deferred_string_key) SerializeDeferredKey(comma, key);
SerializeString(Handle<String>::cast(object));
return SUCCESS;
} else {
DCHECK(object->IsJSReceiver());
if (object->IsCallable()) return UNCHANGED;
// Go to slow path for global proxy and objects requiring access checks.
if (deferred_string_key) SerializeDeferredKey(comma, key);
if (object->IsJSProxy()) {
return SerializeJSProxy(Handle<JSProxy>::cast(object));
}
return SerializeJSObject(Handle<JSObject>::cast(object));
}
}
UNREACHABLE();
return UNCHANGED;
}
JsonStringifier::Result JsonStringifier::SerializeJSValue(
Handle<JSValue> object) {
String* class_name = object->class_name();
if (class_name == isolate_->heap()->String_string()) {
Handle<Object> value;
ASSIGN_RETURN_ON_EXCEPTION_VALUE(
isolate_, value, Object::ToString(isolate_, object), EXCEPTION);
SerializeString(Handle<String>::cast(value));
} else if (class_name == isolate_->heap()->Number_string()) {
Handle<Object> value;
ASSIGN_RETURN_ON_EXCEPTION_VALUE(isolate_, value, Object::ToNumber(object),
EXCEPTION);
if (value->IsSmi()) return SerializeSmi(Smi::cast(*value));
SerializeHeapNumber(Handle<HeapNumber>::cast(value));
} else if (class_name == isolate_->heap()->Boolean_string()) {
Object* value = JSValue::cast(*object)->value();
DCHECK(value->IsBoolean());
builder_.AppendCString(value->IsTrue(isolate_) ? "true" : "false");
} else {
// ES6 24.3.2.1 step 10.c, serialize as an ordinary JSObject.
return SerializeJSObject(object);
}
return SUCCESS;
}
JsonStringifier::Result JsonStringifier::SerializeSmi(Smi* object) {
static const int kBufferSize = 100;
char chars[kBufferSize];
Vector<char> buffer(chars, kBufferSize);
builder_.AppendCString(IntToCString(object->value(), buffer));
return SUCCESS;
}
JsonStringifier::Result JsonStringifier::SerializeDouble(double number) {
if (std::isinf(number) || std::isnan(number)) {
builder_.AppendCString("null");
return SUCCESS;
}
static const int kBufferSize = 100;
char chars[kBufferSize];
Vector<char> buffer(chars, kBufferSize);
builder_.AppendCString(DoubleToCString(number, buffer));
return SUCCESS;
}
JsonStringifier::Result JsonStringifier::SerializeJSArray(
Handle<JSArray> object) {
HandleScope handle_scope(isolate_);
Result stack_push = StackPush(object);
if (stack_push != SUCCESS) return stack_push;
uint32_t length = 0;
CHECK(object->length()->ToArrayLength(&length));
DCHECK(!object->IsAccessCheckNeeded());
builder_.AppendCharacter('[');
Indent();
uint32_t i = 0;
if (replacer_function_.is_null()) {
switch (object->GetElementsKind()) {
case FAST_SMI_ELEMENTS: {
Handle<FixedArray> elements(FixedArray::cast(object->elements()),
isolate_);
StackLimitCheck interrupt_check(isolate_);
while (i < length) {
if (interrupt_check.InterruptRequested() &&
isolate_->stack_guard()->HandleInterrupts()->IsException(
isolate_)) {
return EXCEPTION;
}
Separator(i == 0);
SerializeSmi(Smi::cast(elements->get(i)));
i++;
}
break;
}
case FAST_DOUBLE_ELEMENTS: {
// Empty array is FixedArray but not FixedDoubleArray.
if (length == 0) break;
Handle<FixedDoubleArray> elements(
FixedDoubleArray::cast(object->elements()), isolate_);
StackLimitCheck interrupt_check(isolate_);
while (i < length) {
if (interrupt_check.InterruptRequested() &&
isolate_->stack_guard()->HandleInterrupts()->IsException(
isolate_)) {
return EXCEPTION;
}
Separator(i == 0);
SerializeDouble(elements->get_scalar(i));
i++;
}
break;
}
case FAST_ELEMENTS: {
Handle<Object> old_length(object->length(), isolate_);
while (i < length) {
if (object->length() != *old_length ||
object->GetElementsKind() != FAST_ELEMENTS) {
// Fall back to slow path.
break;
}
Separator(i == 0);
Result result = SerializeElement(
isolate_,
Handle<Object>(FixedArray::cast(object->elements())->get(i),
isolate_),
i);
if (result == UNCHANGED) {
builder_.AppendCString("null");
} else if (result != SUCCESS) {
return result;
}
i++;
}
break;
}
// The FAST_HOLEY_* cases could be handled in a faster way. They resemble
// the non-holey cases except that a lookup is necessary for holes.
default:
break;
}
}
if (i < length) {
// Slow path for non-fast elements and fall-back in edge case.
Result result = SerializeArrayLikeSlow(object, i, length);
if (result != SUCCESS) return result;
}
Unindent();
if (length > 0) NewLine();
builder_.AppendCharacter(']');
StackPop();
return SUCCESS;
}
JsonStringifier::Result JsonStringifier::SerializeArrayLikeSlow(
Handle<JSReceiver> object, uint32_t start, uint32_t length) {
// We need to write out at least two characters per array element.
static const int kMaxSerializableArrayLength = String::kMaxLength / 2;
if (length > kMaxSerializableArrayLength) {
isolate_->Throw(*isolate_->factory()->NewInvalidStringLengthError());
return EXCEPTION;
}
for (uint32_t i = start; i < length; i++) {
Separator(i == 0);
Handle<Object> element;
ASSIGN_RETURN_ON_EXCEPTION_VALUE(
isolate_, element, JSReceiver::GetElement(isolate_, object, i),
EXCEPTION);
Result result = SerializeElement(isolate_, element, i);
if (result == SUCCESS) continue;
if (result == UNCHANGED) {
// Detect overflow sooner for large sparse arrays.
if (builder_.HasOverflowed()) return EXCEPTION;
builder_.AppendCString("null");
} else {
return result;
}
}
return SUCCESS;
}
JsonStringifier::Result JsonStringifier::SerializeJSObject(
Handle<JSObject> object) {
HandleScope handle_scope(isolate_);
Result stack_push = StackPush(object);
if (stack_push != SUCCESS) return stack_push;
if (property_list_.is_null() &&
object->map()->instance_type() > LAST_CUSTOM_ELEMENTS_RECEIVER &&
object->HasFastProperties() &&
Handle<JSObject>::cast(object)->elements()->length() == 0) {
DCHECK(object->IsJSObject());
DCHECK(!object->IsJSGlobalProxy());
Handle<JSObject> js_obj = Handle<JSObject>::cast(object);
DCHECK(!js_obj->HasIndexedInterceptor());
DCHECK(!js_obj->HasNamedInterceptor());
Handle<Map> map(js_obj->map());
builder_.AppendCharacter('{');
Indent();
bool comma = false;
for (int i = 0; i < map->NumberOfOwnDescriptors(); i++) {
Handle<Name> name(map->instance_descriptors()->GetKey(i), isolate_);
// TODO(rossberg): Should this throw?
if (!name->IsString()) continue;
Handle<String> key = Handle<String>::cast(name);
PropertyDetails details = map->instance_descriptors()->GetDetails(i);
if (details.IsDontEnum()) continue;
Handle<Object> property;
if (details.location() == kField && *map == js_obj->map()) {
DCHECK_EQ(kData, details.kind());
FieldIndex field_index = FieldIndex::ForDescriptor(*map, i);
property = JSObject::FastPropertyAt(js_obj, details.representation(),
field_index);
} else {
ASSIGN_RETURN_ON_EXCEPTION_VALUE(
isolate_, property, Object::GetPropertyOrElement(js_obj, key),
EXCEPTION);
}
Result result = SerializeProperty(property, comma, key);
if (!comma && result == SUCCESS) comma = true;
if (result == EXCEPTION) return result;
}
Unindent();
if (comma) NewLine();
builder_.AppendCharacter('}');
} else {
Result result = SerializeJSReceiverSlow(object);
if (result != SUCCESS) return result;
}
StackPop();
return SUCCESS;
}
JsonStringifier::Result JsonStringifier::SerializeJSReceiverSlow(
Handle<JSReceiver> object) {
Handle<FixedArray> contents = property_list_;
if (contents.is_null()) {
ASSIGN_RETURN_ON_EXCEPTION_VALUE(
isolate_, contents,
KeyAccumulator::GetKeys(object, KeyCollectionMode::kOwnOnly,
ENUMERABLE_STRINGS,
GetKeysConversion::kConvertToString),
EXCEPTION);
}
builder_.AppendCharacter('{');
Indent();
bool comma = false;
for (int i = 0; i < contents->length(); i++) {
Handle<String> key(String::cast(contents->get(i)), isolate_);
Handle<Object> property;
ASSIGN_RETURN_ON_EXCEPTION_VALUE(isolate_, property,
Object::GetPropertyOrElement(object, key),
EXCEPTION);
Result result = SerializeProperty(property, comma, key);
if (!comma && result == SUCCESS) comma = true;
if (result == EXCEPTION) return result;
}
Unindent();
if (comma) NewLine();
builder_.AppendCharacter('}');
return SUCCESS;
}
JsonStringifier::Result JsonStringifier::SerializeJSProxy(
Handle<JSProxy> object) {
HandleScope scope(isolate_);
Result stack_push = StackPush(object);
if (stack_push != SUCCESS) return stack_push;
Maybe<bool> is_array = Object::IsArray(object);
if (is_array.IsNothing()) return EXCEPTION;
if (is_array.FromJust()) {
Handle<Object> length_object;
ASSIGN_RETURN_ON_EXCEPTION_VALUE(
isolate_, length_object,
Object::GetLengthFromArrayLike(isolate_, object), EXCEPTION);
uint32_t length;
if (!length_object->ToUint32(&length)) {
// Technically, we need to be able to handle lengths outside the
// uint32_t range. However, we would run into string size overflow
// if we tried to stringify such an array.
isolate_->Throw(*isolate_->factory()->NewInvalidStringLengthError());
return EXCEPTION;
}
builder_.AppendCharacter('[');
Indent();
Result result = SerializeArrayLikeSlow(object, 0, length);
if (result != SUCCESS) return result;
Unindent();
if (length > 0) NewLine();
builder_.AppendCharacter(']');
} else {
Result result = SerializeJSReceiverSlow(object);
if (result != SUCCESS) return result;
}
StackPop();
return SUCCESS;
}
template <typename SrcChar, typename DestChar>
void JsonStringifier::SerializeStringUnchecked_(
Vector<const SrcChar> src,
IncrementalStringBuilder::NoExtend<DestChar>* dest) {
// Assert that uc16 character is not truncated down to 8 bit.
// The <uc16, char> version of this method must not be called.
DCHECK(sizeof(DestChar) >= sizeof(SrcChar));
for (int i = 0; i < src.length(); i++) {
SrcChar c = src[i];
if (DoNotEscape(c)) {
dest->Append(c);
} else {
dest->AppendCString(&JsonEscapeTable[c * kJsonEscapeTableEntrySize]);
}
}
}
template <typename SrcChar, typename DestChar>
void JsonStringifier::SerializeString_(Handle<String> string) {
int length = string->length();
builder_.Append<uint8_t, DestChar>('"');
// We make a rough estimate to find out if the current string can be
// serialized without allocating a new string part. The worst case length of
// an escaped character is 6. Shifting the remainin string length right by 3
// is a more pessimistic estimate, but faster to calculate.
int worst_case_length = length << 3;
if (builder_.CurrentPartCanFit(worst_case_length)) {
DisallowHeapAllocation no_gc;
Vector<const SrcChar> vector = string->GetCharVector<SrcChar>();
IncrementalStringBuilder::NoExtendBuilder<DestChar> no_extend(
&builder_, worst_case_length);
SerializeStringUnchecked_(vector, &no_extend);
} else {
FlatStringReader reader(isolate_, string);
for (int i = 0; i < reader.length(); i++) {
SrcChar c = reader.Get<SrcChar>(i);
if (DoNotEscape(c)) {
builder_.Append<SrcChar, DestChar>(c);
} else {
builder_.AppendCString(&JsonEscapeTable[c * kJsonEscapeTableEntrySize]);
}
}
}
builder_.Append<uint8_t, DestChar>('"');
}
template <>
bool JsonStringifier::DoNotEscape(uint8_t c) {
return c >= '#' && c <= '~' && c != '\\';
}
template <>
bool JsonStringifier::DoNotEscape(uint16_t c) {
return c >= '#' && c != '\\' && c != 0x7f;
}
void JsonStringifier::NewLine() {
if (gap_ == nullptr) return;
builder_.AppendCharacter('\n');
for (int i = 0; i < indent_; i++) builder_.AppendCString(gap_);
}
void JsonStringifier::Separator(bool first) {
if (!first) builder_.AppendCharacter(',');
NewLine();
}
void JsonStringifier::SerializeDeferredKey(bool deferred_comma,
Handle<Object> deferred_key) {
Separator(!deferred_comma);
SerializeString(Handle<String>::cast(deferred_key));
builder_.AppendCharacter(':');
if (gap_ != nullptr) builder_.AppendCharacter(' ');
}
void JsonStringifier::SerializeString(Handle<String> object) {
object = String::Flatten(object);
if (builder_.CurrentEncoding() == String::ONE_BYTE_ENCODING) {
if (object->IsOneByteRepresentationUnderneath()) {
SerializeString_<uint8_t, uint8_t>(object);
} else {
builder_.ChangeEncoding();
SerializeString(object);
}
} else {
if (object->IsOneByteRepresentationUnderneath()) {
SerializeString_<uint8_t, uc16>(object);
} else {
SerializeString_<uc16, uc16>(object);
}
}
}
} // namespace internal
} // namespace v8