1 // Copyright 2012 the V8 project authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
5 #ifndef V8_JSON_STRINGIFIER_H_
6 #define V8_JSON_STRINGIFIER_H_
10 #include "src/conversions.h"
11 #include "src/utils.h"
16 class BasicJsonStringifier BASE_EMBEDDED {
18 explicit BasicJsonStringifier(Isolate* isolate);
20 MUST_USE_RESULT MaybeHandle<Object> Stringify(Handle<Object> object);
22 MUST_USE_RESULT INLINE(static MaybeHandle<Object> StringifyString(
24 Handle<String> object));
27 static const int kInitialPartLength = 32;
28 static const int kMaxPartLength = 16 * 1024;
29 static const int kPartLengthGrowthFactor = 2;
31 enum Result { UNCHANGED, SUCCESS, EXCEPTION };
37 void ChangeEncoding();
39 INLINE(void ShrinkCurrentPart());
41 template <bool is_ascii, typename Char>
42 INLINE(void Append_(Char c));
44 template <bool is_ascii, typename Char>
45 INLINE(void Append_(const Char* chars));
47 INLINE(void Append(uint8_t c)) {
55 INLINE(void AppendAscii(const char* chars)) {
57 Append_<true>(reinterpret_cast<const uint8_t*>(chars));
59 Append_<false>(reinterpret_cast<const uint8_t*>(chars));
63 MUST_USE_RESULT MaybeHandle<Object> ApplyToJsonFunction(
64 Handle<Object> object,
67 Result SerializeGeneric(Handle<Object> object,
72 template <typename ResultType, typename Char>
73 INLINE(static Handle<String> StringifyString_(Isolate* isolate,
75 Handle<String> result));
77 // Entry point to serialize the object.
78 INLINE(Result SerializeObject(Handle<Object> obj)) {
79 return Serialize_<false>(obj, false, factory_->empty_string());
82 // Serialize an array element.
83 // The index may serve as argument for the toJSON function.
84 INLINE(Result SerializeElement(Isolate* isolate,
85 Handle<Object> object,
87 return Serialize_<false>(object,
89 Handle<Object>(Smi::FromInt(i), isolate));
92 // Serialize a object property.
93 // The key may or may not be serialized depending on the property.
94 // The key may also serve as argument for the toJSON function.
95 INLINE(Result SerializeProperty(Handle<Object> object,
97 Handle<String> deferred_key)) {
98 DCHECK(!deferred_key.is_null());
99 return Serialize_<true>(object, deferred_comma, deferred_key);
102 template <bool deferred_string_key>
103 Result Serialize_(Handle<Object> object, bool comma, Handle<Object> key);
105 void SerializeDeferredKey(bool deferred_comma, Handle<Object> deferred_key) {
106 if (deferred_comma) Append(',');
107 SerializeString(Handle<String>::cast(deferred_key));
111 Result SerializeSmi(Smi* object);
113 Result SerializeDouble(double number);
114 INLINE(Result SerializeHeapNumber(Handle<HeapNumber> object)) {
115 return SerializeDouble(object->value());
118 Result SerializeJSValue(Handle<JSValue> object);
120 INLINE(Result SerializeJSArray(Handle<JSArray> object));
121 INLINE(Result SerializeJSObject(Handle<JSObject> object));
123 Result SerializeJSArraySlow(Handle<JSArray> object, uint32_t length);
125 void SerializeString(Handle<String> object);
127 template <typename SrcChar, typename DestChar>
128 INLINE(static int SerializeStringUnchecked_(const SrcChar* src,
132 template <bool is_ascii, typename Char>
133 INLINE(void SerializeString_(Handle<String> string));
135 template <typename Char>
136 INLINE(static bool DoNotEscape(Char c));
138 template <typename Char>
139 INLINE(static Vector<const Char> GetCharVector(Handle<String> string));
141 Result StackPush(Handle<Object> object);
144 INLINE(Handle<String> accumulator()) {
145 return Handle<String>(String::cast(accumulator_store_->value()), isolate_);
148 INLINE(void set_accumulator(Handle<String> string)) {
149 return accumulator_store_->set_value(*string);
154 // We use a value wrapper for the string accumulator to keep the
155 // (indirect) handle to it in the outermost handle scope.
156 Handle<JSValue> accumulator_store_;
157 Handle<String> current_part_;
158 Handle<String> tojson_string_;
159 Handle<JSArray> stack_;
165 static const int kJsonEscapeTableEntrySize = 8;
166 static const char* const JsonEscapeTable;
170 // Translation table to escape ASCII characters.
171 // Table entries start at a multiple of 8 and are null-terminated.
172 const char* const BasicJsonStringifier::JsonEscapeTable =
173 "\\u0000\0 \\u0001\0 \\u0002\0 \\u0003\0 "
174 "\\u0004\0 \\u0005\0 \\u0006\0 \\u0007\0 "
175 "\\b\0 \\t\0 \\n\0 \\u000b\0 "
176 "\\f\0 \\r\0 \\u000e\0 \\u000f\0 "
177 "\\u0010\0 \\u0011\0 \\u0012\0 \\u0013\0 "
178 "\\u0014\0 \\u0015\0 \\u0016\0 \\u0017\0 "
179 "\\u0018\0 \\u0019\0 \\u001a\0 \\u001b\0 "
180 "\\u001c\0 \\u001d\0 \\u001e\0 \\u001f\0 "
181 " \0 !\0 \\\"\0 #\0 "
196 "\\\\\0 ]\0 ^\0 _\0 "
204 "|\0 }\0 ~\0 \177\0 "
205 "\200\0 \201\0 \202\0 \203\0 "
206 "\204\0 \205\0 \206\0 \207\0 "
207 "\210\0 \211\0 \212\0 \213\0 "
208 "\214\0 \215\0 \216\0 \217\0 "
209 "\220\0 \221\0 \222\0 \223\0 "
210 "\224\0 \225\0 \226\0 \227\0 "
211 "\230\0 \231\0 \232\0 \233\0 "
212 "\234\0 \235\0 \236\0 \237\0 "
213 "\240\0 \241\0 \242\0 \243\0 "
214 "\244\0 \245\0 \246\0 \247\0 "
215 "\250\0 \251\0 \252\0 \253\0 "
216 "\254\0 \255\0 \256\0 \257\0 "
217 "\260\0 \261\0 \262\0 \263\0 "
218 "\264\0 \265\0 \266\0 \267\0 "
219 "\270\0 \271\0 \272\0 \273\0 "
220 "\274\0 \275\0 \276\0 \277\0 "
221 "\300\0 \301\0 \302\0 \303\0 "
222 "\304\0 \305\0 \306\0 \307\0 "
223 "\310\0 \311\0 \312\0 \313\0 "
224 "\314\0 \315\0 \316\0 \317\0 "
225 "\320\0 \321\0 \322\0 \323\0 "
226 "\324\0 \325\0 \326\0 \327\0 "
227 "\330\0 \331\0 \332\0 \333\0 "
228 "\334\0 \335\0 \336\0 \337\0 "
229 "\340\0 \341\0 \342\0 \343\0 "
230 "\344\0 \345\0 \346\0 \347\0 "
231 "\350\0 \351\0 \352\0 \353\0 "
232 "\354\0 \355\0 \356\0 \357\0 "
233 "\360\0 \361\0 \362\0 \363\0 "
234 "\364\0 \365\0 \366\0 \367\0 "
235 "\370\0 \371\0 \372\0 \373\0 "
236 "\374\0 \375\0 \376\0 \377\0 ";
239 BasicJsonStringifier::BasicJsonStringifier(Isolate* isolate)
244 factory_ = isolate_->factory();
245 accumulator_store_ = Handle<JSValue>::cast(
246 Object::ToObject(isolate, factory_->empty_string()).ToHandleChecked());
247 part_length_ = kInitialPartLength;
248 current_part_ = factory_->NewRawOneByteString(part_length_).ToHandleChecked();
249 tojson_string_ = factory_->toJSON_string();
250 stack_ = factory_->NewJSArray(8);
254 MaybeHandle<Object> BasicJsonStringifier::Stringify(Handle<Object> object) {
255 Result result = SerializeObject(object);
256 if (result == UNCHANGED) return isolate_->factory()->undefined_value();
257 if (result == SUCCESS) {
261 return isolate_->Throw<Object>(
262 isolate_->factory()->NewInvalidStringLengthError());
264 return accumulator();
266 DCHECK(result == EXCEPTION);
267 return MaybeHandle<Object>();
271 MaybeHandle<Object> BasicJsonStringifier::StringifyString(
272 Isolate* isolate, Handle<String> object) {
273 static const int kJsonQuoteWorstCaseBlowup = 6;
274 static const int kSpaceForQuotes = 2;
275 int worst_case_length =
276 object->length() * kJsonQuoteWorstCaseBlowup + kSpaceForQuotes;
278 if (worst_case_length > 32 * KB) { // Slow path if too large.
279 BasicJsonStringifier stringifier(isolate);
280 return stringifier.Stringify(object);
283 object = String::Flatten(object);
284 DCHECK(object->IsFlat());
285 if (object->IsOneByteRepresentationUnderneath()) {
286 Handle<String> result = isolate->factory()->NewRawOneByteString(
287 worst_case_length).ToHandleChecked();
288 DisallowHeapAllocation no_gc;
289 return StringifyString_<SeqOneByteString>(
291 object->GetFlatContent().ToOneByteVector(),
294 Handle<String> result = isolate->factory()->NewRawTwoByteString(
295 worst_case_length).ToHandleChecked();
296 DisallowHeapAllocation no_gc;
297 return StringifyString_<SeqTwoByteString>(
299 object->GetFlatContent().ToUC16Vector(),
305 template <typename ResultType, typename Char>
306 Handle<String> BasicJsonStringifier::StringifyString_(Isolate* isolate,
308 Handle<String> result) {
309 DisallowHeapAllocation no_gc;
311 ResultType* dest = ResultType::cast(*result);
312 dest->Set(final_size++, '\"');
313 final_size += SerializeStringUnchecked_(vector.start(),
314 dest->GetChars() + 1,
316 dest->Set(final_size++, '\"');
317 return SeqString::Truncate(Handle<SeqString>::cast(result), final_size);
321 template <bool is_ascii, typename Char>
322 void BasicJsonStringifier::Append_(Char c) {
324 SeqOneByteString::cast(*current_part_)->SeqOneByteStringSet(
325 current_index_++, c);
327 SeqTwoByteString::cast(*current_part_)->SeqTwoByteStringSet(
328 current_index_++, c);
330 if (current_index_ == part_length_) Extend();
334 template <bool is_ascii, typename Char>
335 void BasicJsonStringifier::Append_(const Char* chars) {
336 for ( ; *chars != '\0'; chars++) Append_<is_ascii, Char>(*chars);
340 MaybeHandle<Object> BasicJsonStringifier::ApplyToJsonFunction(
341 Handle<Object> object, Handle<Object> key) {
342 LookupIterator it(object, tojson_string_, LookupIterator::SKIP_INTERCEPTOR);
344 ASSIGN_RETURN_ON_EXCEPTION(isolate_, fun, Object::GetProperty(&it), Object);
345 if (!fun->IsJSFunction()) return object;
347 // Call toJSON function.
348 if (key->IsSmi()) key = factory_->NumberToString(key);
349 Handle<Object> argv[] = { key };
350 HandleScope scope(isolate_);
351 ASSIGN_RETURN_ON_EXCEPTION(
353 Execution::Call(isolate_, fun, object, 1, argv),
355 return scope.CloseAndEscape(object);
359 BasicJsonStringifier::Result BasicJsonStringifier::StackPush(
360 Handle<Object> object) {
361 StackLimitCheck check(isolate_);
362 if (check.HasOverflowed()) {
363 isolate_->StackOverflow();
367 int length = Smi::cast(stack_->length())->value();
369 DisallowHeapAllocation no_allocation;
370 FixedArray* elements = FixedArray::cast(stack_->elements());
371 for (int i = 0; i < length; i++) {
372 if (elements->get(i) == *object) {
373 AllowHeapAllocation allow_to_return_error;
374 isolate_->Throw(*factory_->NewTypeError(
375 "circular_structure", HandleVector<Object>(NULL, 0)));
380 JSArray::EnsureSize(stack_, length + 1);
381 FixedArray::cast(stack_->elements())->set(length, *object);
382 stack_->set_length(Smi::FromInt(length + 1));
387 void BasicJsonStringifier::StackPop() {
388 int length = Smi::cast(stack_->length())->value();
389 stack_->set_length(Smi::FromInt(length - 1));
393 template <bool deferred_string_key>
394 BasicJsonStringifier::Result BasicJsonStringifier::Serialize_(
395 Handle<Object> object, bool comma, Handle<Object> key) {
396 if (object->IsJSObject()) {
397 ASSIGN_RETURN_ON_EXCEPTION_VALUE(
399 ApplyToJsonFunction(object, key),
403 if (object->IsSmi()) {
404 if (deferred_string_key) SerializeDeferredKey(comma, key);
405 return SerializeSmi(Smi::cast(*object));
408 switch (HeapObject::cast(*object)->map()->instance_type()) {
409 case HEAP_NUMBER_TYPE:
410 case MUTABLE_HEAP_NUMBER_TYPE:
411 if (deferred_string_key) SerializeDeferredKey(comma, key);
412 return SerializeHeapNumber(Handle<HeapNumber>::cast(object));
414 switch (Oddball::cast(*object)->kind()) {
415 case Oddball::kFalse:
416 if (deferred_string_key) SerializeDeferredKey(comma, key);
417 AppendAscii("false");
420 if (deferred_string_key) SerializeDeferredKey(comma, key);
424 if (deferred_string_key) SerializeDeferredKey(comma, key);
431 if (object->IsAccessCheckNeeded()) break;
432 if (deferred_string_key) SerializeDeferredKey(comma, key);
433 return SerializeJSArray(Handle<JSArray>::cast(object));
435 if (deferred_string_key) SerializeDeferredKey(comma, key);
436 return SerializeJSValue(Handle<JSValue>::cast(object));
437 case JS_FUNCTION_TYPE:
440 if (object->IsString()) {
441 if (deferred_string_key) SerializeDeferredKey(comma, key);
442 SerializeString(Handle<String>::cast(object));
444 } else if (object->IsJSObject()) {
445 // Go to slow path for global proxy and objects requiring access checks.
446 if (object->IsAccessCheckNeeded() || object->IsJSGlobalProxy()) break;
447 if (deferred_string_key) SerializeDeferredKey(comma, key);
448 return SerializeJSObject(Handle<JSObject>::cast(object));
452 return SerializeGeneric(object, key, comma, deferred_string_key);
456 BasicJsonStringifier::Result BasicJsonStringifier::SerializeGeneric(
457 Handle<Object> object,
461 Handle<JSObject> builtins(isolate_->native_context()->builtins(), isolate_);
462 Handle<JSFunction> builtin = Handle<JSFunction>::cast(Object::GetProperty(
463 isolate_, builtins, "JSONSerializeAdapter").ToHandleChecked());
465 Handle<Object> argv[] = { key, object };
466 Handle<Object> result;
467 ASSIGN_RETURN_ON_EXCEPTION_VALUE(
469 Execution::Call(isolate_, builtin, object, 2, argv),
471 if (result->IsUndefined()) return UNCHANGED;
473 if (key->IsSmi()) key = factory_->NumberToString(key);
474 SerializeDeferredKey(deferred_comma, key);
477 Handle<String> result_string = Handle<String>::cast(result);
478 // Shrink current part, attach it to the accumulator, also attach the result
479 // string to the accumulator, and allocate a new part.
480 ShrinkCurrentPart(); // Shrink.
481 part_length_ = kInitialPartLength; // Allocate conservatively.
482 Extend(); // Attach current part and allocate new part.
483 // Attach result string to the accumulator.
485 ASSIGN_RETURN_ON_EXCEPTION_VALUE(
487 factory_->NewConsString(accumulator(), result_string),
489 set_accumulator(cons);
494 BasicJsonStringifier::Result BasicJsonStringifier::SerializeJSValue(
495 Handle<JSValue> object) {
496 String* class_name = object->class_name();
497 if (class_name == isolate_->heap()->String_string()) {
498 Handle<Object> value;
499 ASSIGN_RETURN_ON_EXCEPTION_VALUE(
500 isolate_, value, Execution::ToString(isolate_, object), EXCEPTION);
501 SerializeString(Handle<String>::cast(value));
502 } else if (class_name == isolate_->heap()->Number_string()) {
503 Handle<Object> value;
504 ASSIGN_RETURN_ON_EXCEPTION_VALUE(
505 isolate_, value, Execution::ToNumber(isolate_, object), EXCEPTION);
506 if (value->IsSmi()) return SerializeSmi(Smi::cast(*value));
507 SerializeHeapNumber(Handle<HeapNumber>::cast(value));
509 DCHECK(class_name == isolate_->heap()->Boolean_string());
510 Object* value = JSValue::cast(*object)->value();
511 DCHECK(value->IsBoolean());
512 AppendAscii(value->IsTrue() ? "true" : "false");
518 BasicJsonStringifier::Result BasicJsonStringifier::SerializeSmi(Smi* object) {
519 static const int kBufferSize = 100;
520 char chars[kBufferSize];
521 Vector<char> buffer(chars, kBufferSize);
522 AppendAscii(IntToCString(object->value(), buffer));
527 BasicJsonStringifier::Result BasicJsonStringifier::SerializeDouble(
529 if (std::isinf(number) || std::isnan(number)) {
533 static const int kBufferSize = 100;
534 char chars[kBufferSize];
535 Vector<char> buffer(chars, kBufferSize);
536 AppendAscii(DoubleToCString(number, buffer));
541 BasicJsonStringifier::Result BasicJsonStringifier::SerializeJSArray(
542 Handle<JSArray> object) {
543 HandleScope handle_scope(isolate_);
544 Result stack_push = StackPush(object);
545 if (stack_push != SUCCESS) return stack_push;
547 CHECK(object->length()->ToArrayIndex(&length));
549 switch (object->GetElementsKind()) {
550 case FAST_SMI_ELEMENTS: {
551 Handle<FixedArray> elements(
552 FixedArray::cast(object->elements()), isolate_);
553 for (uint32_t i = 0; i < length; i++) {
554 if (i > 0) Append(',');
555 SerializeSmi(Smi::cast(elements->get(i)));
559 case FAST_DOUBLE_ELEMENTS: {
560 // Empty array is FixedArray but not FixedDoubleArray.
561 if (length == 0) break;
562 Handle<FixedDoubleArray> elements(
563 FixedDoubleArray::cast(object->elements()), isolate_);
564 for (uint32_t i = 0; i < length; i++) {
565 if (i > 0) Append(',');
566 SerializeDouble(elements->get_scalar(i));
570 case FAST_ELEMENTS: {
571 Handle<FixedArray> elements(
572 FixedArray::cast(object->elements()), isolate_);
573 for (uint32_t i = 0; i < length; i++) {
574 if (i > 0) Append(',');
576 SerializeElement(isolate_,
577 Handle<Object>(elements->get(i), isolate_),
579 if (result == SUCCESS) continue;
580 if (result == UNCHANGED) {
588 // TODO(yangguo): The FAST_HOLEY_* cases could be handled in a faster way.
589 // They resemble the non-holey cases except that a prototype chain lookup
590 // is necessary for holes.
592 Result result = SerializeJSArraySlow(object, length);
593 if (result != SUCCESS) return result;
599 current_part_ = handle_scope.CloseAndEscape(current_part_);
604 BasicJsonStringifier::Result BasicJsonStringifier::SerializeJSArraySlow(
605 Handle<JSArray> object, uint32_t length) {
606 for (uint32_t i = 0; i < length; i++) {
607 if (i > 0) Append(',');
608 Handle<Object> element;
609 ASSIGN_RETURN_ON_EXCEPTION_VALUE(
611 Object::GetElement(isolate_, object, i),
613 if (element->IsUndefined()) {
616 Result result = SerializeElement(isolate_, element, i);
617 if (result == SUCCESS) continue;
618 if (result == UNCHANGED) {
629 BasicJsonStringifier::Result BasicJsonStringifier::SerializeJSObject(
630 Handle<JSObject> object) {
631 HandleScope handle_scope(isolate_);
632 Result stack_push = StackPush(object);
633 if (stack_push != SUCCESS) return stack_push;
634 DCHECK(!object->IsJSGlobalProxy() && !object->IsGlobalObject());
639 if (object->HasFastProperties() &&
640 !object->HasIndexedInterceptor() &&
641 !object->HasNamedInterceptor() &&
642 object->elements()->length() == 0) {
643 Handle<Map> map(object->map());
644 for (int i = 0; i < map->NumberOfOwnDescriptors(); i++) {
645 Handle<Name> name(map->instance_descriptors()->GetKey(i), isolate_);
646 // TODO(rossberg): Should this throw?
647 if (!name->IsString()) continue;
648 Handle<String> key = Handle<String>::cast(name);
649 PropertyDetails details = map->instance_descriptors()->GetDetails(i);
650 if (details.IsDontEnum()) continue;
651 Handle<Object> property;
652 if (details.type() == FIELD && *map == object->map()) {
653 property = Handle<Object>(object->RawFastPropertyAt(
654 FieldIndex::ForDescriptor(*map, i)), isolate_);
656 ASSIGN_RETURN_ON_EXCEPTION_VALUE(
658 Object::GetPropertyOrElement(object, key),
661 Result result = SerializeProperty(property, comma, key);
662 if (!comma && result == SUCCESS) comma = true;
663 if (result == EXCEPTION) return result;
666 Handle<FixedArray> contents;
667 ASSIGN_RETURN_ON_EXCEPTION_VALUE(
669 JSReceiver::GetKeys(object, JSReceiver::OWN_ONLY),
672 for (int i = 0; i < contents->length(); i++) {
673 Object* key = contents->get(i);
674 Handle<String> key_handle;
675 MaybeHandle<Object> maybe_property;
676 if (key->IsString()) {
677 key_handle = Handle<String>(String::cast(key), isolate_);
678 maybe_property = Object::GetPropertyOrElement(object, key_handle);
680 DCHECK(key->IsNumber());
681 key_handle = factory_->NumberToString(Handle<Object>(key, isolate_));
684 maybe_property = Object::GetElement(
685 isolate_, object, Smi::cast(key)->value());
686 } else if (key_handle->AsArrayIndex(&index)) {
687 maybe_property = Object::GetElement(isolate_, object, index);
689 maybe_property = Object::GetPropertyOrElement(object, key_handle);
692 Handle<Object> property;
693 ASSIGN_RETURN_ON_EXCEPTION_VALUE(
694 isolate_, property, maybe_property, EXCEPTION);
695 Result result = SerializeProperty(property, comma, key_handle);
696 if (!comma && result == SUCCESS) comma = true;
697 if (result == EXCEPTION) return result;
703 current_part_ = handle_scope.CloseAndEscape(current_part_);
708 void BasicJsonStringifier::ShrinkCurrentPart() {
709 DCHECK(current_index_ < part_length_);
710 current_part_ = SeqString::Truncate(Handle<SeqString>::cast(current_part_),
715 void BasicJsonStringifier::Accumulate() {
716 if (accumulator()->length() + current_part_->length() > String::kMaxLength) {
717 // Screw it. Simply set the flag and carry on. Throw exception at the end.
718 set_accumulator(factory_->empty_string());
721 set_accumulator(factory_->NewConsString(accumulator(),
722 current_part_).ToHandleChecked());
727 void BasicJsonStringifier::Extend() {
729 if (part_length_ <= kMaxPartLength / kPartLengthGrowthFactor) {
730 part_length_ *= kPartLengthGrowthFactor;
734 factory_->NewRawOneByteString(part_length_).ToHandleChecked();
737 factory_->NewRawTwoByteString(part_length_).ToHandleChecked();
739 DCHECK(!current_part_.is_null());
744 void BasicJsonStringifier::ChangeEncoding() {
748 factory_->NewRawTwoByteString(part_length_).ToHandleChecked();
749 DCHECK(!current_part_.is_null());
755 template <typename SrcChar, typename DestChar>
756 int BasicJsonStringifier::SerializeStringUnchecked_(const SrcChar* src,
759 DestChar* dest_start = dest;
761 // Assert that uc16 character is not truncated down to 8 bit.
762 // The <uc16, char> version of this method must not be called.
763 DCHECK(sizeof(*dest) >= sizeof(*src));
765 for (int i = 0; i < length; i++) {
767 if (DoNotEscape(c)) {
768 *(dest++) = static_cast<DestChar>(c);
770 const uint8_t* chars = reinterpret_cast<const uint8_t*>(
771 &JsonEscapeTable[c * kJsonEscapeTableEntrySize]);
772 while (*chars != '\0') *(dest++) = *(chars++);
776 return static_cast<int>(dest - dest_start);
780 template <bool is_ascii, typename Char>
781 void BasicJsonStringifier::SerializeString_(Handle<String> string) {
782 int length = string->length();
783 Append_<is_ascii, char>('"');
784 // We make a rough estimate to find out if the current string can be
785 // serialized without allocating a new string part. The worst case length of
786 // an escaped character is 6. Shifting the remainin string length right by 3
787 // is a more pessimistic estimate, but faster to calculate.
789 if (((part_length_ - current_index_) >> 3) > length) {
790 DisallowHeapAllocation no_gc;
791 Vector<const Char> vector = GetCharVector<Char>(string);
793 current_index_ += SerializeStringUnchecked_(
795 SeqOneByteString::cast(*current_part_)->GetChars() + current_index_,
798 current_index_ += SerializeStringUnchecked_(
800 SeqTwoByteString::cast(*current_part_)->GetChars() + current_index_,
804 String* string_location = NULL;
805 Vector<const Char> vector(NULL, 0);
806 for (int i = 0; i < length; i++) {
807 // If GC moved the string, we need to refresh the vector.
808 if (*string != string_location) {
809 DisallowHeapAllocation no_gc;
810 // This does not actually prevent the string from being relocated later.
811 vector = GetCharVector<Char>(string);
812 string_location = *string;
815 if (DoNotEscape(c)) {
816 Append_<is_ascii, Char>(c);
818 Append_<is_ascii, uint8_t>(reinterpret_cast<const uint8_t*>(
819 &JsonEscapeTable[c * kJsonEscapeTableEntrySize]));
824 Append_<is_ascii, uint8_t>('"');
829 bool BasicJsonStringifier::DoNotEscape(uint8_t c) {
830 return c >= '#' && c <= '~' && c != '\\';
835 bool BasicJsonStringifier::DoNotEscape(uint16_t c) {
836 return c >= '#' && c != '\\' && c != 0x7f;
841 Vector<const uint8_t> BasicJsonStringifier::GetCharVector(
842 Handle<String> string) {
843 String::FlatContent flat = string->GetFlatContent();
844 DCHECK(flat.IsAscii());
845 return flat.ToOneByteVector();
850 Vector<const uc16> BasicJsonStringifier::GetCharVector(Handle<String> string) {
851 String::FlatContent flat = string->GetFlatContent();
852 DCHECK(flat.IsTwoByte());
853 return flat.ToUC16Vector();
857 void BasicJsonStringifier::SerializeString(Handle<String> object) {
858 object = String::Flatten(object);
860 if (object->IsOneByteRepresentationUnderneath()) {
861 SerializeString_<true, uint8_t>(object);
864 SerializeString(object);
867 if (object->IsOneByteRepresentationUnderneath()) {
868 SerializeString_<false, uint8_t>(object);
870 SerializeString_<false, uc16>(object);
875 } } // namespace v8::internal
877 #endif // V8_JSON_STRINGIFIER_H_