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/string-builder.h"
12 #include "src/utils.h"
17 class BasicJsonStringifier BASE_EMBEDDED {
19 explicit BasicJsonStringifier(Isolate* isolate);
21 MUST_USE_RESULT MaybeHandle<Object> Stringify(Handle<Object> object);
23 MUST_USE_RESULT INLINE(static MaybeHandle<Object> StringifyString(
25 Handle<String> object));
28 enum Result { UNCHANGED, SUCCESS, EXCEPTION };
30 MUST_USE_RESULT MaybeHandle<Object> ApplyToJsonFunction(
31 Handle<Object> object,
34 Result SerializeGeneric(Handle<Object> object,
39 // Entry point to serialize the object.
40 INLINE(Result SerializeObject(Handle<Object> obj)) {
41 return Serialize_<false>(obj, false, factory()->empty_string());
44 // Serialize an array element.
45 // The index may serve as argument for the toJSON function.
46 INLINE(Result SerializeElement(Isolate* isolate,
47 Handle<Object> object,
49 return Serialize_<false>(object,
51 Handle<Object>(Smi::FromInt(i), isolate));
54 // Serialize a object property.
55 // The key may or may not be serialized depending on the property.
56 // The key may also serve as argument for the toJSON function.
57 INLINE(Result SerializeProperty(Handle<Object> object,
59 Handle<String> deferred_key)) {
60 DCHECK(!deferred_key.is_null());
61 return Serialize_<true>(object, deferred_comma, deferred_key);
64 template <bool deferred_string_key>
65 Result Serialize_(Handle<Object> object, bool comma, Handle<Object> key);
67 void SerializeDeferredKey(bool deferred_comma, Handle<Object> deferred_key) {
68 if (deferred_comma) builder_.AppendCharacter(',');
69 SerializeString(Handle<String>::cast(deferred_key));
70 builder_.AppendCharacter(':');
73 Result SerializeSmi(Smi* object);
75 Result SerializeDouble(double number);
76 INLINE(Result SerializeHeapNumber(Handle<HeapNumber> object)) {
77 return SerializeDouble(object->value());
80 Result SerializeJSValue(Handle<JSValue> object);
82 INLINE(Result SerializeJSArray(Handle<JSArray> object));
83 INLINE(Result SerializeJSObject(Handle<JSObject> object));
85 Result SerializeJSArraySlow(Handle<JSArray> object, uint32_t length);
87 void SerializeString(Handle<String> object);
89 template <typename SrcChar, typename DestChar>
90 INLINE(static void SerializeStringUnchecked_(
91 Vector<const SrcChar> src,
92 IncrementalStringBuilder::NoExtend<DestChar>* dest));
94 template <typename SrcChar, typename DestChar>
95 INLINE(void SerializeString_(Handle<String> string));
97 template <typename Char>
98 INLINE(static bool DoNotEscape(Char c));
100 Result StackPush(Handle<Object> object);
103 Factory* factory() { return isolate_->factory(); }
106 IncrementalStringBuilder builder_;
107 Handle<String> tojson_string_;
108 Handle<JSArray> stack_;
110 static const int kJsonEscapeTableEntrySize = 8;
111 static const char* const JsonEscapeTable;
115 // Translation table to escape Latin1 characters.
116 // Table entries start at a multiple of 8 and are null-terminated.
117 const char* const BasicJsonStringifier::JsonEscapeTable =
118 "\\u0000\0 \\u0001\0 \\u0002\0 \\u0003\0 "
119 "\\u0004\0 \\u0005\0 \\u0006\0 \\u0007\0 "
120 "\\b\0 \\t\0 \\n\0 \\u000b\0 "
121 "\\f\0 \\r\0 \\u000e\0 \\u000f\0 "
122 "\\u0010\0 \\u0011\0 \\u0012\0 \\u0013\0 "
123 "\\u0014\0 \\u0015\0 \\u0016\0 \\u0017\0 "
124 "\\u0018\0 \\u0019\0 \\u001a\0 \\u001b\0 "
125 "\\u001c\0 \\u001d\0 \\u001e\0 \\u001f\0 "
126 " \0 !\0 \\\"\0 #\0 "
141 "\\\\\0 ]\0 ^\0 _\0 "
149 "|\0 }\0 ~\0 \177\0 "
150 "\200\0 \201\0 \202\0 \203\0 "
151 "\204\0 \205\0 \206\0 \207\0 "
152 "\210\0 \211\0 \212\0 \213\0 "
153 "\214\0 \215\0 \216\0 \217\0 "
154 "\220\0 \221\0 \222\0 \223\0 "
155 "\224\0 \225\0 \226\0 \227\0 "
156 "\230\0 \231\0 \232\0 \233\0 "
157 "\234\0 \235\0 \236\0 \237\0 "
158 "\240\0 \241\0 \242\0 \243\0 "
159 "\244\0 \245\0 \246\0 \247\0 "
160 "\250\0 \251\0 \252\0 \253\0 "
161 "\254\0 \255\0 \256\0 \257\0 "
162 "\260\0 \261\0 \262\0 \263\0 "
163 "\264\0 \265\0 \266\0 \267\0 "
164 "\270\0 \271\0 \272\0 \273\0 "
165 "\274\0 \275\0 \276\0 \277\0 "
166 "\300\0 \301\0 \302\0 \303\0 "
167 "\304\0 \305\0 \306\0 \307\0 "
168 "\310\0 \311\0 \312\0 \313\0 "
169 "\314\0 \315\0 \316\0 \317\0 "
170 "\320\0 \321\0 \322\0 \323\0 "
171 "\324\0 \325\0 \326\0 \327\0 "
172 "\330\0 \331\0 \332\0 \333\0 "
173 "\334\0 \335\0 \336\0 \337\0 "
174 "\340\0 \341\0 \342\0 \343\0 "
175 "\344\0 \345\0 \346\0 \347\0 "
176 "\350\0 \351\0 \352\0 \353\0 "
177 "\354\0 \355\0 \356\0 \357\0 "
178 "\360\0 \361\0 \362\0 \363\0 "
179 "\364\0 \365\0 \366\0 \367\0 "
180 "\370\0 \371\0 \372\0 \373\0 "
181 "\374\0 \375\0 \376\0 \377\0 ";
184 BasicJsonStringifier::BasicJsonStringifier(Isolate* isolate)
185 : isolate_(isolate), builder_(isolate) {
186 tojson_string_ = factory()->toJSON_string();
187 stack_ = factory()->NewJSArray(8);
191 MaybeHandle<Object> BasicJsonStringifier::Stringify(Handle<Object> object) {
192 Result result = SerializeObject(object);
193 if (result == UNCHANGED) return factory()->undefined_value();
194 if (result == SUCCESS) return builder_.Finish();
195 DCHECK(result == EXCEPTION);
196 return MaybeHandle<Object>();
200 MaybeHandle<Object> BasicJsonStringifier::StringifyString(
201 Isolate* isolate, Handle<String> object) {
202 static const int kJsonQuoteWorstCaseBlowup = 6;
203 static const int kSpaceForQuotes = 2;
204 int worst_case_length =
205 object->length() * kJsonQuoteWorstCaseBlowup + kSpaceForQuotes;
207 if (worst_case_length > 32 * KB) { // Slow path if too large.
208 BasicJsonStringifier stringifier(isolate);
209 return stringifier.Stringify(object);
212 object = String::Flatten(object);
213 DCHECK(object->IsFlat());
214 Handle<SeqString> result;
215 if (object->IsOneByteRepresentationUnderneath()) {
216 result = isolate->factory()
217 ->NewRawOneByteString(worst_case_length)
219 IncrementalStringBuilder::NoExtendString<uint8_t> no_extend(
220 result, worst_case_length);
221 no_extend.Append('\"');
222 SerializeStringUnchecked_(object->GetFlatContent().ToOneByteVector(),
224 no_extend.Append('\"');
226 result = isolate->factory()
227 ->NewRawTwoByteString(worst_case_length)
229 IncrementalStringBuilder::NoExtendString<uc16> no_extend(result,
231 no_extend.Append('\"');
232 SerializeStringUnchecked_(object->GetFlatContent().ToUC16Vector(),
234 no_extend.Append('\"');
240 MaybeHandle<Object> BasicJsonStringifier::ApplyToJsonFunction(
241 Handle<Object> object, Handle<Object> key) {
242 LookupIterator it(object, tojson_string_,
243 LookupIterator::PROTOTYPE_CHAIN_SKIP_INTERCEPTOR);
245 ASSIGN_RETURN_ON_EXCEPTION(isolate_, fun, Object::GetProperty(&it), Object);
246 if (!fun->IsJSFunction()) return object;
248 // Call toJSON function.
249 if (key->IsSmi()) key = factory()->NumberToString(key);
250 Handle<Object> argv[] = { key };
251 HandleScope scope(isolate_);
252 ASSIGN_RETURN_ON_EXCEPTION(
254 Execution::Call(isolate_, fun, object, 1, argv),
256 return scope.CloseAndEscape(object);
260 BasicJsonStringifier::Result BasicJsonStringifier::StackPush(
261 Handle<Object> object) {
262 StackLimitCheck check(isolate_);
263 if (check.HasOverflowed()) {
264 isolate_->StackOverflow();
268 int length = Smi::cast(stack_->length())->value();
270 DisallowHeapAllocation no_allocation;
271 FixedArray* elements = FixedArray::cast(stack_->elements());
272 for (int i = 0; i < length; i++) {
273 if (elements->get(i) == *object) {
274 AllowHeapAllocation allow_to_return_error;
275 Handle<Object> error;
276 MaybeHandle<Object> maybe_error = factory()->NewTypeError(
277 "circular_structure", HandleVector<Object>(NULL, 0));
278 if (maybe_error.ToHandle(&error)) isolate_->Throw(*error);
283 JSArray::EnsureSize(stack_, length + 1);
284 FixedArray::cast(stack_->elements())->set(length, *object);
285 stack_->set_length(Smi::FromInt(length + 1));
290 void BasicJsonStringifier::StackPop() {
291 int length = Smi::cast(stack_->length())->value();
292 stack_->set_length(Smi::FromInt(length - 1));
296 template <bool deferred_string_key>
297 BasicJsonStringifier::Result BasicJsonStringifier::Serialize_(
298 Handle<Object> object, bool comma, Handle<Object> key) {
299 if (object->IsJSObject()) {
300 ASSIGN_RETURN_ON_EXCEPTION_VALUE(
302 ApplyToJsonFunction(object, key),
306 if (object->IsSmi()) {
307 if (deferred_string_key) SerializeDeferredKey(comma, key);
308 return SerializeSmi(Smi::cast(*object));
311 switch (HeapObject::cast(*object)->map()->instance_type()) {
312 case HEAP_NUMBER_TYPE:
313 case MUTABLE_HEAP_NUMBER_TYPE:
314 if (deferred_string_key) SerializeDeferredKey(comma, key);
315 return SerializeHeapNumber(Handle<HeapNumber>::cast(object));
317 switch (Oddball::cast(*object)->kind()) {
318 case Oddball::kFalse:
319 if (deferred_string_key) SerializeDeferredKey(comma, key);
320 builder_.AppendCString("false");
323 if (deferred_string_key) SerializeDeferredKey(comma, key);
324 builder_.AppendCString("true");
327 if (deferred_string_key) SerializeDeferredKey(comma, key);
328 builder_.AppendCString("null");
334 if (object->IsAccessCheckNeeded()) break;
335 if (deferred_string_key) SerializeDeferredKey(comma, key);
336 return SerializeJSArray(Handle<JSArray>::cast(object));
338 if (deferred_string_key) SerializeDeferredKey(comma, key);
339 return SerializeJSValue(Handle<JSValue>::cast(object));
340 case JS_FUNCTION_TYPE:
343 if (object->IsString()) {
344 if (deferred_string_key) SerializeDeferredKey(comma, key);
345 SerializeString(Handle<String>::cast(object));
347 } else if (object->IsJSObject()) {
348 // Go to slow path for global proxy and objects requiring access checks.
349 if (object->IsAccessCheckNeeded() || object->IsJSGlobalProxy()) break;
350 if (deferred_string_key) SerializeDeferredKey(comma, key);
351 return SerializeJSObject(Handle<JSObject>::cast(object));
355 return SerializeGeneric(object, key, comma, deferred_string_key);
359 BasicJsonStringifier::Result BasicJsonStringifier::SerializeGeneric(
360 Handle<Object> object,
364 Handle<JSObject> builtins(isolate_->native_context()->builtins(), isolate_);
365 Handle<JSFunction> builtin = Handle<JSFunction>::cast(Object::GetProperty(
366 isolate_, builtins, "JSONSerializeAdapter").ToHandleChecked());
368 Handle<Object> argv[] = { key, object };
369 Handle<Object> result;
370 ASSIGN_RETURN_ON_EXCEPTION_VALUE(
372 Execution::Call(isolate_, builtin, object, 2, argv),
374 if (result->IsUndefined()) return UNCHANGED;
376 if (key->IsSmi()) key = factory()->NumberToString(key);
377 SerializeDeferredKey(deferred_comma, key);
380 builder_.AppendString(Handle<String>::cast(result));
385 BasicJsonStringifier::Result BasicJsonStringifier::SerializeJSValue(
386 Handle<JSValue> object) {
387 String* class_name = object->class_name();
388 if (class_name == isolate_->heap()->String_string()) {
389 Handle<Object> value;
390 ASSIGN_RETURN_ON_EXCEPTION_VALUE(
391 isolate_, value, Execution::ToString(isolate_, object), EXCEPTION);
392 SerializeString(Handle<String>::cast(value));
393 } else if (class_name == isolate_->heap()->Number_string()) {
394 Handle<Object> value;
395 ASSIGN_RETURN_ON_EXCEPTION_VALUE(
396 isolate_, value, Execution::ToNumber(isolate_, object), EXCEPTION);
397 if (value->IsSmi()) return SerializeSmi(Smi::cast(*value));
398 SerializeHeapNumber(Handle<HeapNumber>::cast(value));
400 DCHECK(class_name == isolate_->heap()->Boolean_string());
401 Object* value = JSValue::cast(*object)->value();
402 DCHECK(value->IsBoolean());
403 builder_.AppendCString(value->IsTrue() ? "true" : "false");
409 BasicJsonStringifier::Result BasicJsonStringifier::SerializeSmi(Smi* object) {
410 static const int kBufferSize = 100;
411 char chars[kBufferSize];
412 Vector<char> buffer(chars, kBufferSize);
413 builder_.AppendCString(IntToCString(object->value(), buffer));
418 BasicJsonStringifier::Result BasicJsonStringifier::SerializeDouble(
420 if (std::isinf(number) || std::isnan(number)) {
421 builder_.AppendCString("null");
424 static const int kBufferSize = 100;
425 char chars[kBufferSize];
426 Vector<char> buffer(chars, kBufferSize);
427 builder_.AppendCString(DoubleToCString(number, buffer));
432 BasicJsonStringifier::Result BasicJsonStringifier::SerializeJSArray(
433 Handle<JSArray> object) {
434 HandleScope handle_scope(isolate_);
435 Result stack_push = StackPush(object);
436 if (stack_push != SUCCESS) return stack_push;
438 CHECK(object->length()->ToArrayIndex(&length));
439 builder_.AppendCharacter('[');
440 switch (object->GetElementsKind()) {
441 case FAST_SMI_ELEMENTS: {
442 Handle<FixedArray> elements(
443 FixedArray::cast(object->elements()), isolate_);
444 for (uint32_t i = 0; i < length; i++) {
445 if (i > 0) builder_.AppendCharacter(',');
446 SerializeSmi(Smi::cast(elements->get(i)));
450 case FAST_DOUBLE_ELEMENTS: {
451 // Empty array is FixedArray but not FixedDoubleArray.
452 if (length == 0) break;
453 Handle<FixedDoubleArray> elements(
454 FixedDoubleArray::cast(object->elements()), isolate_);
455 for (uint32_t i = 0; i < length; i++) {
456 if (i > 0) builder_.AppendCharacter(',');
457 SerializeDouble(elements->get_scalar(i));
461 case FAST_ELEMENTS: {
462 Handle<FixedArray> elements(
463 FixedArray::cast(object->elements()), isolate_);
464 for (uint32_t i = 0; i < length; i++) {
465 if (i > 0) builder_.AppendCharacter(',');
467 SerializeElement(isolate_,
468 Handle<Object>(elements->get(i), isolate_),
470 if (result == SUCCESS) continue;
471 if (result == UNCHANGED) {
472 builder_.AppendCString("null");
479 // TODO(yangguo): The FAST_HOLEY_* cases could be handled in a faster way.
480 // They resemble the non-holey cases except that a prototype chain lookup
481 // is necessary for holes.
483 Result result = SerializeJSArraySlow(object, length);
484 if (result != SUCCESS) return result;
488 builder_.AppendCharacter(']');
494 BasicJsonStringifier::Result BasicJsonStringifier::SerializeJSArraySlow(
495 Handle<JSArray> object, uint32_t length) {
496 for (uint32_t i = 0; i < length; i++) {
497 if (i > 0) builder_.AppendCharacter(',');
498 Handle<Object> element;
499 ASSIGN_RETURN_ON_EXCEPTION_VALUE(
501 Object::GetElement(isolate_, object, i),
503 if (element->IsUndefined()) {
504 builder_.AppendCString("null");
506 Result result = SerializeElement(isolate_, element, i);
507 if (result == SUCCESS) continue;
508 if (result == UNCHANGED) {
509 builder_.AppendCString("null");
519 BasicJsonStringifier::Result BasicJsonStringifier::SerializeJSObject(
520 Handle<JSObject> object) {
521 HandleScope handle_scope(isolate_);
522 Result stack_push = StackPush(object);
523 if (stack_push != SUCCESS) return stack_push;
524 DCHECK(!object->IsJSGlobalProxy() && !object->IsGlobalObject());
526 builder_.AppendCharacter('{');
529 if (object->HasFastProperties() &&
530 !object->HasIndexedInterceptor() &&
531 !object->HasNamedInterceptor() &&
532 object->elements()->length() == 0) {
533 Handle<Map> map(object->map());
534 for (int i = 0; i < map->NumberOfOwnDescriptors(); i++) {
535 Handle<Name> name(map->instance_descriptors()->GetKey(i), isolate_);
536 // TODO(rossberg): Should this throw?
537 if (!name->IsString()) continue;
538 Handle<String> key = Handle<String>::cast(name);
539 PropertyDetails details = map->instance_descriptors()->GetDetails(i);
540 if (details.IsDontEnum()) continue;
541 Handle<Object> property;
542 if (details.type() == DATA && *map == object->map()) {
543 FieldIndex field_index = FieldIndex::ForDescriptor(*map, i);
544 Isolate* isolate = object->GetIsolate();
545 if (object->IsUnboxedDoubleField(field_index)) {
546 double value = object->RawFastDoublePropertyAt(field_index);
547 property = isolate->factory()->NewHeapNumber(value);
550 property = handle(object->RawFastPropertyAt(field_index), isolate);
553 ASSIGN_RETURN_ON_EXCEPTION_VALUE(
555 Object::GetPropertyOrElement(object, key),
558 Result result = SerializeProperty(property, comma, key);
559 if (!comma && result == SUCCESS) comma = true;
560 if (result == EXCEPTION) return result;
563 Handle<FixedArray> contents;
564 ASSIGN_RETURN_ON_EXCEPTION_VALUE(
566 JSReceiver::GetKeys(object, JSReceiver::OWN_ONLY),
569 for (int i = 0; i < contents->length(); i++) {
570 Object* key = contents->get(i);
571 Handle<String> key_handle;
572 MaybeHandle<Object> maybe_property;
573 if (key->IsString()) {
574 key_handle = Handle<String>(String::cast(key), isolate_);
575 maybe_property = Object::GetPropertyOrElement(object, key_handle);
577 DCHECK(key->IsNumber());
578 key_handle = factory()->NumberToString(Handle<Object>(key, isolate_));
581 maybe_property = Object::GetElement(
582 isolate_, object, Smi::cast(key)->value());
583 } else if (key_handle->AsArrayIndex(&index)) {
584 maybe_property = Object::GetElement(isolate_, object, index);
586 maybe_property = Object::GetPropertyOrElement(object, key_handle);
589 Handle<Object> property;
590 ASSIGN_RETURN_ON_EXCEPTION_VALUE(
591 isolate_, property, maybe_property, EXCEPTION);
592 Result result = SerializeProperty(property, comma, key_handle);
593 if (!comma && result == SUCCESS) comma = true;
594 if (result == EXCEPTION) return result;
598 builder_.AppendCharacter('}');
604 template <typename SrcChar, typename DestChar>
605 void BasicJsonStringifier::SerializeStringUnchecked_(
606 Vector<const SrcChar> src,
607 IncrementalStringBuilder::NoExtend<DestChar>* dest) {
608 // Assert that uc16 character is not truncated down to 8 bit.
609 // The <uc16, char> version of this method must not be called.
610 DCHECK(sizeof(DestChar) >= sizeof(SrcChar));
612 for (int i = 0; i < src.length(); i++) {
614 if (DoNotEscape(c)) {
617 dest->AppendCString(&JsonEscapeTable[c * kJsonEscapeTableEntrySize]);
623 template <typename SrcChar, typename DestChar>
624 void BasicJsonStringifier::SerializeString_(Handle<String> string) {
625 int length = string->length();
626 builder_.Append<uint8_t, DestChar>('"');
627 // We make a rough estimate to find out if the current string can be
628 // serialized without allocating a new string part. The worst case length of
629 // an escaped character is 6. Shifting the remainin string length right by 3
630 // is a more pessimistic estimate, but faster to calculate.
631 int worst_case_length = length << 3;
632 if (builder_.CurrentPartCanFit(worst_case_length)) {
633 DisallowHeapAllocation no_gc;
634 Vector<const SrcChar> vector = string->GetCharVector<SrcChar>();
635 IncrementalStringBuilder::NoExtendBuilder<DestChar> no_extend(
636 &builder_, worst_case_length);
637 SerializeStringUnchecked_(vector, &no_extend);
639 FlatStringReader reader(isolate_, string);
640 for (int i = 0; i < reader.length(); i++) {
641 SrcChar c = reader.Get<SrcChar>(i);
642 if (DoNotEscape(c)) {
643 builder_.Append<SrcChar, DestChar>(c);
645 builder_.AppendCString(&JsonEscapeTable[c * kJsonEscapeTableEntrySize]);
650 builder_.Append<uint8_t, DestChar>('"');
655 bool BasicJsonStringifier::DoNotEscape(uint8_t c) {
656 return c >= '#' && c <= '~' && c != '\\';
661 bool BasicJsonStringifier::DoNotEscape(uint16_t c) {
662 return c >= '#' && c != '\\' && c != 0x7f;
666 void BasicJsonStringifier::SerializeString(Handle<String> object) {
667 object = String::Flatten(object);
668 if (builder_.CurrentEncoding() == String::ONE_BYTE_ENCODING) {
669 if (object->IsOneByteRepresentationUnderneath()) {
670 SerializeString_<uint8_t, uint8_t>(object);
672 builder_.ChangeEncoding();
673 SerializeString(object);
676 if (object->IsOneByteRepresentationUnderneath()) {
677 SerializeString_<uint8_t, uc16>(object);
679 SerializeString_<uc16, uc16>(object);
684 } } // namespace v8::internal
686 #endif // V8_JSON_STRINGIFIER_H_