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Unified Diff: src/parsing/json-parser.h

Issue 1681513002: [json parser] add position to error message. (Closed) Base URL: https://chromium.googlesource.com/v8/v8.git@master
Patch Set: fix BUILD.gn Created 4 years, 10 months ago
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Index: src/parsing/json-parser.h
diff --git a/src/parsing/json-parser.h b/src/parsing/json-parser.h
deleted file mode 100644
index 096e18801cabf4978886ee10683391ced7f6d3ad..0000000000000000000000000000000000000000
--- a/src/parsing/json-parser.h
+++ /dev/null
@@ -1,842 +0,0 @@
-// Copyright 2011 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.
-
-#ifndef V8_PARSING_JSON_PARSER_H_
-#define V8_PARSING_JSON_PARSER_H_
-
-#include "src/char-predicates.h"
-#include "src/conversions.h"
-#include "src/debug/debug.h"
-#include "src/factory.h"
-#include "src/messages.h"
-#include "src/parsing/scanner.h"
-#include "src/parsing/token.h"
-#include "src/transitions.h"
-#include "src/types.h"
-
-namespace v8 {
-namespace internal {
-
-enum ParseElementResult { kElementFound, kElementNotFound, kNullHandle };
-
-
-// A simple json parser.
-template <bool seq_one_byte>
-class JsonParser BASE_EMBEDDED {
- public:
- MUST_USE_RESULT static MaybeHandle<Object> Parse(Handle<String> source) {
- return JsonParser(source).ParseJson();
- }
-
- static const int kEndOfString = -1;
-
- private:
- explicit JsonParser(Handle<String> source)
- : source_(source),
- source_length_(source->length()),
- isolate_(source->map()->GetHeap()->isolate()),
- factory_(isolate_->factory()),
- 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_);
- }
- }
-
- // Parse a string containing a single JSON value.
- MaybeHandle<Object> ParseJson();
-
- inline void Advance() {
- position_++;
- if (position_ >= source_length_) {
- c0_ = kEndOfString;
- } else if (seq_one_byte) {
- c0_ = seq_source_->SeqOneByteStringGet(position_);
- } else {
- c0_ = source_->Get(position_);
- }
- }
-
- // The JSON lexical grammar is specified in the ECMAScript 5 standard,
- // section 15.12.1.1. The only allowed whitespace characters between tokens
- // are tab, carriage-return, newline and space.
-
- inline void AdvanceSkipWhitespace() {
- do {
- Advance();
- } while (c0_ == ' ' || c0_ == '\t' || c0_ == '\n' || c0_ == '\r');
- }
-
- inline void SkipWhitespace() {
- while (c0_ == ' ' || c0_ == '\t' || c0_ == '\n' || c0_ == '\r') {
- Advance();
- }
- }
-
- inline uc32 AdvanceGetChar() {
- Advance();
- return c0_;
- }
-
- // Checks that current charater is c.
- // If so, then consume c and skip whitespace.
- inline bool MatchSkipWhiteSpace(uc32 c) {
- if (c0_ == c) {
- AdvanceSkipWhitespace();
- return true;
- }
- return false;
- }
-
- // A JSON string (production JSONString) is subset of valid JavaScript string
- // literals. The string must only be double-quoted (not single-quoted), and
- // the only allowed backslash-escapes are ", /, \, b, f, n, r, t and
- // four-digit hex escapes (uXXXX). Any other use of backslashes is invalid.
- Handle<String> ParseJsonString() {
- return ScanJsonString<false>();
- }
-
- bool 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;
- }
-
- Handle<String> ParseJsonInternalizedString() {
- return ScanJsonString<true>();
- }
-
- template <bool is_internalized>
- Handle<String> ScanJsonString();
- // Creates a new string and copies prefix[start..end] into the beginning
- // of it. Then scans the rest of the string, adding characters after the
- // prefix. Called by ScanJsonString when reaching a '\' or non-Latin1 char.
- template <typename StringType, typename SinkChar>
- Handle<String> SlowScanJsonString(Handle<String> prefix, int start, int end);
-
- // A JSON number (production JSONNumber) is a subset of the valid JavaScript
- // decimal number literals.
- // It includes an optional minus sign, must have at least one
- // digit before and after a decimal point, may not have prefixed zeros (unless
- // the integer part is zero), and may include an exponent part (e.g., "e-10").
- // Hexadecimal and octal numbers are not allowed.
- Handle<Object> ParseJsonNumber();
-
- // Parse a single JSON value from input (grammar production JSONValue).
- // A JSON value is either a (double-quoted) string literal, a number literal,
- // one of "true", "false", or "null", or an object or array literal.
- Handle<Object> ParseJsonValue();
-
- // Parse a JSON object literal (grammar production JSONObject).
- // An object literal is a squiggly-braced and comma separated sequence
- // (possibly empty) of key/value pairs, where the key is a JSON string
- // literal, the value is a JSON value, and the two are separated by a colon.
- // A JSON array doesn't allow numbers and identifiers as keys, like a
- // JavaScript array.
- Handle<Object> ParseJsonObject();
-
- // Helper for ParseJsonObject. Parses the form "123": obj, which is recorded
- // as an element, not a property.
- ParseElementResult ParseElement(Handle<JSObject> json_object);
-
- // Parses a JSON array literal (grammar production JSONArray). An array
- // literal is a square-bracketed and comma separated sequence (possibly empty)
- // of JSON values.
- // A JSON array doesn't allow leaving out values from the sequence, nor does
- // it allow a terminal comma, like a JavaScript array does.
- Handle<Object> ParseJsonArray();
-
-
- // Mark that a parsing error has happened at the current token, and
- // return a null handle. Primarily for readability.
- inline Handle<Object> ReportUnexpectedCharacter() {
- return Handle<Object>::null();
- }
-
- inline Isolate* isolate() { return isolate_; }
- inline Factory* factory() { return factory_; }
- inline Handle<JSFunction> object_constructor() { return object_constructor_; }
-
- static const int kInitialSpecialStringLength = 32;
- static const int kPretenureTreshold = 100 * 1024;
-
-
- private:
- Zone* zone() { return &zone_; }
-
- void CommitStateToJsonObject(Handle<JSObject> json_object, Handle<Map> map,
- ZoneList<Handle<Object> >* properties);
-
- Handle<String> source_;
- int source_length_;
- Handle<SeqOneByteString> seq_source_;
-
- PretenureFlag pretenure_;
- Isolate* isolate_;
- Factory* factory_;
- Zone zone_;
- Handle<JSFunction> object_constructor_;
- uc32 c0_;
- int position_;
-};
-
-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<String> argument;
-
- switch (c0_) {
- case kEndOfString:
- message = MessageTemplate::kUnexpectedEOS;
- break;
- case '-':
- case '0':
- case '1':
- case '2':
- case '3':
- case '4':
- case '5':
- case '6':
- case '7':
- case '8':
- case '9':
- message = MessageTemplate::kUnexpectedTokenNumber;
- break;
- case '"':
- message = MessageTemplate::kUnexpectedTokenString;
- break;
- default:
- message = MessageTemplate::kUnexpectedToken;
- argument = 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, argument);
- return isolate()->template Throw<Object>(error, &location);
- }
- return result;
-}
-
-
-// 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()) {
- ExecutionAccess access(isolate_);
- // Avoid blocking GC in long running parser (v8:3974).
- isolate_->stack_guard()->HandleGCInterrupt();
- }
-
- 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;
- ZoneList<Handle<Object> > properties(8, 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) {
- key = TransitionArray::ExpectedTransitionKey(map);
- follow_expected = !key.is_null() && ParseJsonString(key);
- }
- // If the expected transition hits, follow it.
- if (follow_expected) {
- target = TransitionArray::ExpectedTransitionTarget(map);
- } else {
- // 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 = TransitionArray::FindTransitionToField(map, 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::GeneralizeFieldType(target, descriptor,
- expected_representation, value_type);
- }
- DCHECK(target->instance_descriptors()
- ->GetFieldType(descriptor)
- ->NowContains(value));
- properties.Add(value, zone());
- 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,
- ZoneList<Handle<Object> >* properties) {
- JSObject::AllocateStorageForMap(json_object, map);
- DCHECK(!json_object->map()->is_dictionary_map());
-
- DisallowHeapAllocation no_gc;
-
- int length = properties->length();
- for (int i = 0; i < length; i++) {
- Handle<Object> value = (*properties)[i];
- json_object->WriteToField(i, *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());
- ZoneList<Handle<Object> > elements(4, zone());
- DCHECK_EQ(c0_, '[');
-
- AdvanceSkipWhitespace();
- if (c0_ != ']') {
- do {
- Handle<Object> element = ParseJsonValue();
- if (element.is_null()) return ReportUnexpectedCharacter();
- elements.Add(element, zone());
- } while (MatchSkipWhiteSpace(','));
- if (c0_ != ']') {
- return ReportUnexpectedCharacter();
- }
- }
- AdvanceSkipWhitespace();
- // Allocate a fixed array with all the elements.
- Handle<FixedArray> fast_elements =
- factory()->NewFixedArray(elements.length(), pretenure_);
- for (int i = 0, n = elements.length(); i < n; i++) {
- fast_elements->set(i, *elements[i]);
- }
- Handle<Object> json_array = factory()->NewJSArrayWithElements(
- fast_elements, FAST_ELEMENTS, Strength::WEAK, pretenure_);
- 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.
- 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) return Handle<String>::null();
- running_hash = StringHasher::AddCharacterCore(running_hash,
- static_cast<uint16_t>(c0));
- position++;
- if (position >= source_length_) 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 == isolate()->heap()->undefined_value()) {
- // Lookup failure.
- result = factory()->InternalizeOneByteString(
- seq_source_, position_, length);
- break;
- }
- if (element != isolate()->heap()->the_hole_value() &&
- 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;
-}
-
-} // namespace internal
-} // namespace v8
-
-#endif // V8_PARSING_JSON_PARSER_H_
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