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Diffstat (limited to 'deps/v8/src/json-stringifier.h')
| -rw-r--r-- | deps/v8/src/json-stringifier.h | 791 |
1 files changed, 791 insertions, 0 deletions
diff --git a/deps/v8/src/json-stringifier.h b/deps/v8/src/json-stringifier.h new file mode 100644 index 000000000..ad9ef3ddb --- /dev/null +++ b/deps/v8/src/json-stringifier.h @@ -0,0 +1,791 @@ +// Copyright 2012 the V8 project authors. All rights reserved. +// Redistribution and use in source and binary forms, with or without +// modification, are permitted provided that the following conditions are +// met: +// +// * Redistributions of source code must retain the above copyright +// notice, this list of conditions and the following disclaimer. +// * Redistributions in binary form must reproduce the above +// copyright notice, this list of conditions and the following +// disclaimer in the documentation and/or other materials provided +// with the distribution. +// * Neither the name of Google Inc. nor the names of its +// contributors may be used to endorse or promote products derived +// from this software without specific prior written permission. +// +// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +#ifndef V8_JSON_STRINGIFIER_H_ +#define V8_JSON_STRINGIFIER_H_ + +#include "v8.h" +#include "v8utils.h" +#include "v8conversions.h" + +namespace v8 { +namespace internal { + +class BasicJsonStringifier BASE_EMBEDDED { + public: + explicit BasicJsonStringifier(Isolate* isolate); + + MaybeObject* Stringify(Handle<Object> object); + + private: + static const int kInitialPartLength = 32; + static const int kMaxPartLength = 16 * 1024; + static const int kPartLengthGrowthFactor = 2; + + enum Result { UNCHANGED, SUCCESS, EXCEPTION, CIRCULAR, STACK_OVERFLOW }; + + void Extend(); + + void ChangeEncoding(); + + void ShrinkCurrentPart(); + + template <bool is_ascii, typename Char> + INLINE(void Append_(Char c)); + + template <bool is_ascii, typename Char> + INLINE(void Append_(const Char* chars)); + + INLINE(void Append(uint8_t c)) { + if (is_ascii_) { + Append_<true>(c); + } else { + Append_<false>(c); + } + } + + INLINE(void AppendAscii(const char* chars)) { + if (is_ascii_) { + Append_<true>(reinterpret_cast<const uint8_t*>(chars)); + } else { + Append_<false>(reinterpret_cast<const uint8_t*>(chars)); + } + } + + Handle<Object> ApplyToJsonFunction(Handle<Object> object, + Handle<Object> key); + + Result SerializeGeneric(Handle<Object> object, + Handle<Object> key, + bool deferred_comma, + bool deferred_key); + + // Entry point to serialize the object. + INLINE(Result SerializeObject(Handle<Object> obj)) { + return Serialize_<false>(obj, false, factory_->empty_string()); + } + + // Serialize an array element. + // The index may serve as argument for the toJSON function. + INLINE(Result SerializeElement(Isolate* isolate, + Handle<Object> object, + int i)) { + return Serialize_<false>(object, + false, + Handle<Object>(Smi::FromInt(i), isolate)); + } + + // Serialize a object property. + // The key may or may not be serialized depending on the property. + // The key may also serve as argument for the toJSON function. + INLINE(Result SerializeProperty(Handle<Object> object, + bool deferred_comma, + Handle<String> deferred_key)) { + ASSERT(!deferred_key.is_null()); + return Serialize_<true>(object, deferred_comma, deferred_key); + } + + template <bool deferred_string_key> + Result Serialize_(Handle<Object> object, bool comma, Handle<Object> key); + + void SerializeDeferredKey(bool deferred_comma, Handle<Object> deferred_key) { + if (deferred_comma) Append(','); + SerializeString(Handle<String>::cast(deferred_key)); + Append(':'); + } + + Result SerializeSmi(Smi* object); + + Result SerializeDouble(double number); + INLINE(Result SerializeHeapNumber(Handle<HeapNumber> object)) { + return SerializeDouble(object->value()); + } + + Result SerializeJSValue(Handle<JSValue> object); + + INLINE(Result SerializeJSArray(Handle<JSArray> object)); + INLINE(Result SerializeJSObject(Handle<JSObject> object)); + + Result SerializeJSArraySlow(Handle<JSArray> object, int length); + + void SerializeString(Handle<String> object); + + template <typename SrcChar, typename DestChar> + INLINE(void SerializeStringUnchecked_(const SrcChar* src, + DestChar* dest, + int length)); + + template <bool is_ascii, typename Char> + INLINE(void SerializeString_(Handle<String> string)); + + template <typename Char> + INLINE(bool DoNotEscape(Char c)); + + template <typename Char> + INLINE(Vector<const Char> GetCharVector(Handle<String> string)); + + Result StackPush(Handle<Object> object); + void StackPop(); + + INLINE(Handle<String> accumulator()) { + return Handle<String>(String::cast(accumulator_store_->value()), isolate_); + } + + INLINE(void set_accumulator(Handle<String> string)) { + return accumulator_store_->set_value(*string); + } + + Isolate* isolate_; + Factory* factory_; + // We use a value wrapper for the string accumulator to keep the + // (indirect) handle to it in the outermost handle scope. + Handle<JSValue> accumulator_store_; + Handle<String> current_part_; + Handle<String> tojson_string_; + Handle<JSArray> stack_; + int current_index_; + int part_length_; + bool is_ascii_; + + static const int kJsonEscapeTableEntrySize = 8; + static const char* const JsonEscapeTable; +}; + + +// Translation table to escape ASCII characters. +// Table entries start at a multiple of 8 and are null-terminated. +const char* const BasicJsonStringifier::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 "; + +BasicJsonStringifier::BasicJsonStringifier(Isolate* isolate) + : isolate_(isolate), current_index_(0), is_ascii_(true) { + factory_ = isolate_->factory(); + accumulator_store_ = Handle<JSValue>::cast( + factory_->ToObject(factory_->empty_string())); + part_length_ = kInitialPartLength; + current_part_ = factory_->NewRawOneByteString(kInitialPartLength); + tojson_string_ = + factory_->InternalizeOneByteString(STATIC_ASCII_VECTOR("toJSON")); + stack_ = factory_->NewJSArray(8); +} + + +MaybeObject* BasicJsonStringifier::Stringify(Handle<Object> object) { + switch (SerializeObject(object)) { + case UNCHANGED: + return isolate_->heap()->undefined_value(); + case SUCCESS: + ShrinkCurrentPart(); + return *factory_->NewConsString(accumulator(), current_part_); + case CIRCULAR: + return isolate_->Throw(*factory_->NewTypeError( + "circular_structure", HandleVector<Object>(NULL, 0))); + case STACK_OVERFLOW: + return isolate_->StackOverflow(); + default: + return Failure::Exception(); + } +} + + +template <bool is_ascii, typename Char> +void BasicJsonStringifier::Append_(Char c) { + if (is_ascii) { + SeqOneByteString::cast(*current_part_)->SeqOneByteStringSet( + current_index_++, c); + } else { + SeqTwoByteString::cast(*current_part_)->SeqTwoByteStringSet( + current_index_++, c); + } + if (current_index_ == part_length_) Extend(); +} + + +template <bool is_ascii, typename Char> +void BasicJsonStringifier::Append_(const Char* chars) { + for ( ; *chars != '\0'; chars++) Append_<is_ascii, Char>(*chars); +} + + +Handle<Object> BasicJsonStringifier::ApplyToJsonFunction( + Handle<Object> object, Handle<Object> key) { + LookupResult lookup(isolate_); + JSObject::cast(*object)->LookupRealNamedProperty(*tojson_string_, &lookup); + if (!lookup.IsProperty()) return object; + PropertyAttributes attr; + Handle<Object> fun = + Object::GetProperty(object, object, &lookup, tojson_string_, &attr); + if (!fun->IsJSFunction()) return object; + + // Call toJSON function. + if (key->IsSmi()) key = factory_->NumberToString(key); + Handle<Object> argv[] = { key }; + bool has_exception = false; + HandleScope scope(isolate_); + object = Execution::Call(fun, object, 1, argv, &has_exception); + // Return empty handle to signal an exception. + if (has_exception) return Handle<Object>::null(); + return scope.CloseAndEscape(object); +} + + +BasicJsonStringifier::Result BasicJsonStringifier::StackPush( + Handle<Object> object) { + StackLimitCheck check(isolate_); + if (check.HasOverflowed()) return STACK_OVERFLOW; + + int length = Smi::cast(stack_->length())->value(); + FixedArray* elements = FixedArray::cast(stack_->elements()); + for (int i = 0; i < length; i++) { + if (elements->get(i) == *object) { + return CIRCULAR; + } + } + stack_->EnsureSize(length + 1); + FixedArray::cast(stack_->elements())->set(length, *object); + stack_->set_length(Smi::FromInt(length + 1)); + return SUCCESS; +} + + +void BasicJsonStringifier::StackPop() { + int length = Smi::cast(stack_->length())->value(); + stack_->set_length(Smi::FromInt(length - 1)); +} + + +template <bool deferred_string_key> +BasicJsonStringifier::Result BasicJsonStringifier::Serialize_( + Handle<Object> object, bool comma, Handle<Object> key) { + if (object->IsJSObject()) { + object = ApplyToJsonFunction(object, key); + if (object.is_null()) return 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: + 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); + AppendAscii("false"); + return SUCCESS; + case Oddball::kTrue: + if (deferred_string_key) SerializeDeferredKey(comma, key); + AppendAscii("true"); + return SUCCESS; + case Oddball::kNull: + if (deferred_string_key) SerializeDeferredKey(comma, key); + AppendAscii("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 JS_FUNCTION_TYPE: + return UNCHANGED; + default: + if (object->IsString()) { + if (deferred_string_key) SerializeDeferredKey(comma, key); + SerializeString(Handle<String>::cast(object)); + return SUCCESS; + } else if (object->IsJSObject()) { + if (deferred_string_key) SerializeDeferredKey(comma, key); + return SerializeJSObject(Handle<JSObject>::cast(object)); + } else { + return SerializeGeneric(object, key, comma, deferred_string_key); + } + } +} + + +BasicJsonStringifier::Result BasicJsonStringifier::SerializeGeneric( + Handle<Object> object, + Handle<Object> key, + bool deferred_comma, + bool deferred_key) { + Handle<JSObject> builtins(isolate_->native_context()->builtins()); + Handle<JSFunction> builtin = + Handle<JSFunction>::cast(GetProperty(builtins, "JSONSerializeAdapter")); + + Handle<Object> argv[] = { key, object }; + bool has_exception = false; + Handle<Object> result = + Execution::Call(builtin, object, 2, argv, &has_exception); + if (has_exception) return EXCEPTION; + if (result->IsUndefined()) return UNCHANGED; + if (deferred_key) { + if (key->IsSmi()) key = factory_->NumberToString(key); + SerializeDeferredKey(deferred_comma, key); + } + + Handle<String> result_string = Handle<String>::cast(result); + // Shrink current part, attach it to the accumulator, also attach the result + // string to the accumulator, and allocate a new part. + ShrinkCurrentPart(); // Shrink. + part_length_ = kInitialPartLength; // Allocate conservatively. + Extend(); // Attach current part and allocate new part. + // Attach result string to the accumulator. + set_accumulator(factory_->NewConsString(accumulator(), result_string)); + return SUCCESS; +} + + +BasicJsonStringifier::Result BasicJsonStringifier::SerializeJSValue( + Handle<JSValue> object) { + bool has_exception = false; + String* class_name = object->class_name(); + if (class_name == isolate_->heap()->String_string()) { + Handle<Object> value = Execution::ToString(object, &has_exception); + if (has_exception) return EXCEPTION; + SerializeString(Handle<String>::cast(value)); + } else if (class_name == isolate_->heap()->Number_string()) { + Handle<Object> value = Execution::ToNumber(object, &has_exception); + if (has_exception) return EXCEPTION; + if (value->IsSmi()) return SerializeSmi(Smi::cast(*value)); + SerializeHeapNumber(Handle<HeapNumber>::cast(value)); + } else { + ASSERT(class_name == isolate_->heap()->Boolean_string()); + Object* value = JSValue::cast(*object)->value(); + ASSERT(value->IsBoolean()); + AppendAscii(value->IsTrue() ? "true" : "false"); + } + return SUCCESS; +} + + +BasicJsonStringifier::Result BasicJsonStringifier::SerializeSmi(Smi* object) { + static const int kBufferSize = 100; + char chars[kBufferSize]; + Vector<char> buffer(chars, kBufferSize); + AppendAscii(IntToCString(object->value(), buffer)); + return SUCCESS; +} + + +BasicJsonStringifier::Result BasicJsonStringifier::SerializeDouble( + double number) { + if (isinf(number) || isnan(number)) { + AppendAscii("null"); + return SUCCESS; + } + static const int kBufferSize = 100; + char chars[kBufferSize]; + Vector<char> buffer(chars, kBufferSize); + AppendAscii(DoubleToCString(number, buffer)); + return SUCCESS; +} + + +BasicJsonStringifier::Result BasicJsonStringifier::SerializeJSArray( + Handle<JSArray> object) { + HandleScope handle_scope(isolate_); + Result stack_push = StackPush(object); + if (stack_push != SUCCESS) return stack_push; + int length = Smi::cast(object->length())->value(); + Append('['); + switch (object->GetElementsKind()) { + case FAST_SMI_ELEMENTS: { + Handle<FixedArray> elements( + FixedArray::cast(object->elements()), isolate_); + for (int i = 0; i < length; i++) { + if (i > 0) Append(','); + SerializeSmi(Smi::cast(elements->get(i))); + } + break; + } + case FAST_DOUBLE_ELEMENTS: { + Handle<FixedDoubleArray> elements( + FixedDoubleArray::cast(object->elements()), isolate_); + for (int i = 0; i < length; i++) { + if (i > 0) Append(','); + SerializeDouble(elements->get_scalar(i)); + } + break; + } + case FAST_ELEMENTS: { + Handle<FixedArray> elements( + FixedArray::cast(object->elements()), isolate_); + for (int i = 0; i < length; i++) { + if (i > 0) Append(','); + Result result = + SerializeElement(isolate_, + Handle<Object>(elements->get(i), isolate_), + i); + if (result == SUCCESS) continue; + if (result == UNCHANGED) { + AppendAscii("null"); + } else { + return result; + } + } + break; + } + // TODO(yangguo): The FAST_HOLEY_* cases could be handled in a faster way. + // They resemble the non-holey cases except that a prototype chain lookup + // is necessary for holes. + default: { + Result result = SerializeJSArraySlow(object, length); + if (result != SUCCESS) return result; + break; + } + } + Append(']'); + StackPop(); + current_part_ = handle_scope.CloseAndEscape(current_part_); + return SUCCESS; +} + + +BasicJsonStringifier::Result BasicJsonStringifier::SerializeJSArraySlow( + Handle<JSArray> object, int length) { + for (int i = 0; i < length; i++) { + if (i > 0) Append(','); + Handle<Object> element = Object::GetElement(object, i); + if (element->IsUndefined()) { + AppendAscii("null"); + } else { + Result result = SerializeElement(object->GetIsolate(), element, i); + if (result == SUCCESS) continue; + if (result == UNCHANGED) { + AppendAscii("null"); + } else { + return result; + } + } + } + return SUCCESS; +} + + +BasicJsonStringifier::Result BasicJsonStringifier::SerializeJSObject( + Handle<JSObject> object) { + HandleScope handle_scope(isolate_); + Result stack_push = StackPush(object); + if (stack_push != SUCCESS) return stack_push; + if (object->IsJSGlobalProxy()) { + object = Handle<JSObject>( + JSObject::cast(object->GetPrototype()), isolate_); + ASSERT(object->IsGlobalObject()); + } + + Append('{'); + bool comma = false; + + if (object->HasFastProperties() && + !object->HasIndexedInterceptor() && + !object->HasNamedInterceptor() && + object->elements()->length() == 0) { + Handle<Map> map(object->map()); + 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() || details.IsDeleted()) continue; + Handle<Object> property; + if (details.type() == FIELD && *map == object->map()) { + property = Handle<Object>( + object->FastPropertyAt( + map->instance_descriptors()->GetFieldIndex(i)), + isolate_); + } else { + property = GetProperty(isolate_, object, key); + if (property.is_null()) return EXCEPTION; + } + Result result = SerializeProperty(property, comma, key); + if (!comma && result == SUCCESS) comma = true; + if (result >= EXCEPTION) return result; + } + } else { + bool has_exception = false; + Handle<FixedArray> contents = + GetKeysInFixedArrayFor(object, LOCAL_ONLY, &has_exception); + if (has_exception) return EXCEPTION; + + for (int i = 0; i < contents->length(); i++) { + Object* key = contents->get(i); + Handle<String> key_handle; + Handle<Object> property; + if (key->IsString()) { + key_handle = Handle<String>(String::cast(key), isolate_); + property = GetProperty(isolate_, object, key_handle); + } else { + ASSERT(key->IsNumber()); + key_handle = factory_->NumberToString(Handle<Object>(key, isolate_)); + uint32_t index; + if (key->IsSmi()) { + property = Object::GetElement(object, Smi::cast(key)->value()); + } else if (key_handle->AsArrayIndex(&index)) { + property = Object::GetElement(object, index); + } else { + property = GetProperty(isolate_, object, key_handle); + } + } + if (property.is_null()) return EXCEPTION; + Result result = SerializeProperty(property, comma, key_handle); + if (!comma && result == SUCCESS) comma = true; + if (result >= EXCEPTION) return result; + } + } + + Append('}'); + StackPop(); + current_part_ = handle_scope.CloseAndEscape(current_part_); + return SUCCESS; +} + + +void BasicJsonStringifier::ShrinkCurrentPart() { + ASSERT(current_index_ < part_length_); + current_part_ = Handle<String>( + SeqString::cast(*current_part_)->Truncate(current_index_), isolate_); +} + + +void BasicJsonStringifier::Extend() { + set_accumulator(factory_->NewConsString(accumulator(), current_part_)); + if (part_length_ <= kMaxPartLength / kPartLengthGrowthFactor) { + part_length_ *= kPartLengthGrowthFactor; + } + if (is_ascii_) { + current_part_ = factory_->NewRawOneByteString(part_length_); + } else { + current_part_ = factory_->NewRawTwoByteString(part_length_); + } + current_index_ = 0; +} + + +void BasicJsonStringifier::ChangeEncoding() { + ShrinkCurrentPart(); + set_accumulator(factory_->NewConsString(accumulator(), current_part_)); + current_part_ = factory_->NewRawTwoByteString(part_length_); + current_index_ = 0; + is_ascii_ = false; +} + + +template <typename SrcChar, typename DestChar> +void BasicJsonStringifier::SerializeStringUnchecked_(const SrcChar* src, + DestChar* dest, + int length) { + dest += current_index_; + DestChar* dest_start = dest; + + // Assert that uc16 character is not truncated down to 8 bit. + // The <uc16, char> version of this method must not be called. + ASSERT(sizeof(*dest) >= sizeof(*src)); + + for (int i = 0; i < length; i++) { + SrcChar c = src[i]; + if (DoNotEscape(c)) { + *(dest++) = static_cast<DestChar>(c); + } else { + const uint8_t* chars = reinterpret_cast<const uint8_t*>( + &JsonEscapeTable[c * kJsonEscapeTableEntrySize]); + while (*chars != '\0') *(dest++) = *(chars++); + } + } + + current_index_ += static_cast<int>(dest - dest_start); +} + + +template <bool is_ascii, typename Char> +void BasicJsonStringifier::SerializeString_(Handle<String> string) { + int length = string->length(); + Append_<is_ascii, char>('"'); + // 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. + + if (((part_length_ - current_index_) >> 3) > length) { + AssertNoAllocation no_allocation; + Vector<const Char> vector = GetCharVector<Char>(string); + if (is_ascii) { + SerializeStringUnchecked_( + vector.start(), + SeqOneByteString::cast(*current_part_)->GetChars(), + length); + } else { + SerializeStringUnchecked_( + vector.start(), + SeqTwoByteString::cast(*current_part_)->GetChars(), + length); + } + } else { + String* string_location = *string; + Vector<const Char> vector = GetCharVector<Char>(string); + for (int i = 0; i < length; i++) { + Char c = vector[i]; + if (DoNotEscape(c)) { + Append_<is_ascii, Char>(c); + } else { + Append_<is_ascii, uint8_t>(reinterpret_cast<const uint8_t*>( + &JsonEscapeTable[c * kJsonEscapeTableEntrySize])); + } + // If GC moved the string, we need to refresh the vector. + if (*string != string_location) { + vector = GetCharVector<Char>(string); + string_location = *string; + } + } + } + + Append_<is_ascii, uint8_t>('"'); +} + + +template <> +bool BasicJsonStringifier::DoNotEscape(uint8_t c) { + return c >= '#' && c <= '~' && c != '\\'; +} + + +template <> +bool BasicJsonStringifier::DoNotEscape(uint16_t c) { + return c >= '#' && c != '\\' && c != 0x7f; +} + + +template <> +Vector<const uint8_t> BasicJsonStringifier::GetCharVector( + Handle<String> string) { + String::FlatContent flat = string->GetFlatContent(); + ASSERT(flat.IsAscii()); + return flat.ToOneByteVector(); +} + + +template <> +Vector<const uc16> BasicJsonStringifier::GetCharVector(Handle<String> string) { + String::FlatContent flat = string->GetFlatContent(); + ASSERT(flat.IsTwoByte()); + return flat.ToUC16Vector(); +} + + +void BasicJsonStringifier::SerializeString(Handle<String> object) { + FlattenString(object); + String::FlatContent flat = object->GetFlatContent(); + if (is_ascii_) { + if (flat.IsAscii()) { + SerializeString_<true, uint8_t>(object); + } else { + ChangeEncoding(); + SerializeString(object); + } + } else { + if (flat.IsAscii()) { + SerializeString_<false, uint8_t>(object); + } else { + SerializeString_<false, uc16>(object); + } + } +} + +} } // namespace v8::internal + +#endif // V8_JSON_STRINGIFIER_H_ |