| // Copyright 2011 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_PARSER_H_ |
| #define V8_JSON_PARSER_H_ |
| |
| #include "v8.h" |
| |
| #include "char-predicates-inl.h" |
| #include "v8conversions.h" |
| #include "messages.h" |
| #include "spaces-inl.h" |
| #include "token.h" |
| |
| namespace v8 { |
| namespace internal { |
| |
| // A simple json parser. |
| template <bool seq_ascii> |
| class JsonParser BASE_EMBEDDED { |
| public: |
| static Handle<Object> Parse(Handle<String> source) { |
| return JsonParser().ParseJson(source); |
| } |
| |
| static const int kEndOfString = -1; |
| |
| private: |
| // Parse a string containing a single JSON value. |
| Handle<Object> ParseJson(Handle<String> source); |
| |
| inline void Advance() { |
| position_++; |
| if (position_ >= source_length_) { |
| c0_ = kEndOfString; |
| } else if (seq_ascii) { |
| c0_ = seq_source_->SeqAsciiStringGet(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_ == '\t' || c0_ == '\r' || c0_ == '\n' || c0_ == ' '); |
| } |
| |
| inline void SkipWhitespace() { |
| while (c0_ == '\t' || c0_ == '\r' || c0_ == '\n' || c0_ == ' ') { |
| 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>(); |
| } |
| Handle<String> ParseJsonSymbol() { |
| return ScanJsonString<true>(); |
| } |
| template <bool is_symbol> |
| 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-ASCII 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(); |
| |
| // 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_; } |
| |
| static const int kInitialSpecialStringLength = 1024; |
| |
| |
| private: |
| Handle<String> source_; |
| int source_length_; |
| Handle<SeqAsciiString> seq_source_; |
| |
| Isolate* isolate_; |
| uc32 c0_; |
| int position_; |
| }; |
| |
| template <bool seq_ascii> |
| Handle<Object> JsonParser<seq_ascii>::ParseJson(Handle<String> source) { |
| isolate_ = source->map()->GetHeap()->isolate(); |
| FlattenString(source); |
| source_ = source; |
| source_length_ = source_->length(); |
| |
| // Optimized fast case where we only have ASCII characters. |
| if (seq_ascii) { |
| seq_source_ = Handle<SeqAsciiString>::cast(source_); |
| } |
| |
| // Set initial position right before the string. |
| position_ = -1; |
| // Advance to the first character (possibly EOS) |
| AdvanceSkipWhitespace(); |
| Handle<Object> result = ParseJsonValue(); |
| if (result.is_null() || c0_ != kEndOfString) { |
| // Parse failed. Current character is the unexpected token. |
| |
| const char* message; |
| Factory* factory = isolate()->factory(); |
| Handle<JSArray> array; |
| |
| switch (c0_) { |
| case kEndOfString: |
| message = "unexpected_eos"; |
| array = factory->NewJSArray(0); |
| break; |
| case '-': |
| case '0': |
| case '1': |
| case '2': |
| case '3': |
| case '4': |
| case '5': |
| case '6': |
| case '7': |
| case '8': |
| case '9': |
| message = "unexpected_token_number"; |
| array = factory->NewJSArray(0); |
| break; |
| case '"': |
| message = "unexpected_token_string"; |
| array = factory->NewJSArray(0); |
| break; |
| default: |
| message = "unexpected_token"; |
| Handle<Object> name = LookupSingleCharacterStringFromCode(c0_); |
| Handle<FixedArray> element = factory->NewFixedArray(1); |
| element->set(0, *name); |
| array = factory->NewJSArrayWithElements(element); |
| break; |
| } |
| |
| MessageLocation location(factory->NewScript(source), |
| position_, |
| position_ + 1); |
| Handle<Object> result = factory->NewSyntaxError(message, array); |
| isolate()->Throw(*result, &location); |
| return Handle<Object>::null(); |
| } |
| return result; |
| } |
| |
| |
| // Parse any JSON value. |
| template <bool seq_ascii> |
| Handle<Object> JsonParser<seq_ascii>::ParseJsonValue() { |
| switch (c0_) { |
| case '"': |
| return ParseJsonString(); |
| case '-': |
| case '0': |
| case '1': |
| case '2': |
| case '3': |
| case '4': |
| case '5': |
| case '6': |
| case '7': |
| case '8': |
| case '9': |
| return ParseJsonNumber(); |
| case 'f': |
| if (AdvanceGetChar() == 'a' && AdvanceGetChar() == 'l' && |
| AdvanceGetChar() == 's' && AdvanceGetChar() == 'e') { |
| AdvanceSkipWhitespace(); |
| return isolate()->factory()->false_value(); |
| } else { |
| return ReportUnexpectedCharacter(); |
| } |
| case 't': |
| if (AdvanceGetChar() == 'r' && AdvanceGetChar() == 'u' && |
| AdvanceGetChar() == 'e') { |
| AdvanceSkipWhitespace(); |
| return isolate()->factory()->true_value(); |
| } else { |
| return ReportUnexpectedCharacter(); |
| } |
| case 'n': |
| if (AdvanceGetChar() == 'u' && AdvanceGetChar() == 'l' && |
| AdvanceGetChar() == 'l') { |
| AdvanceSkipWhitespace(); |
| return isolate()->factory()->null_value(); |
| } else { |
| return ReportUnexpectedCharacter(); |
| } |
| case '{': |
| return ParseJsonObject(); |
| case '[': |
| return ParseJsonArray(); |
| default: |
| return ReportUnexpectedCharacter(); |
| } |
| } |
| |
| |
| // Parse a JSON object. Position must be right at '{'. |
| template <bool seq_ascii> |
| Handle<Object> JsonParser<seq_ascii>::ParseJsonObject() { |
| Handle<JSFunction> object_constructor( |
| isolate()->global_context()->object_function()); |
| Handle<JSObject> json_object = |
| isolate()->factory()->NewJSObject(object_constructor); |
| ASSERT_EQ(c0_, '{'); |
| |
| AdvanceSkipWhitespace(); |
| if (c0_ != '}') { |
| do { |
| if (c0_ != '"') return ReportUnexpectedCharacter(); |
| Handle<String> key = ParseJsonSymbol(); |
| if (key.is_null() || c0_ != ':') return ReportUnexpectedCharacter(); |
| AdvanceSkipWhitespace(); |
| Handle<Object> value = ParseJsonValue(); |
| if (value.is_null()) return ReportUnexpectedCharacter(); |
| |
| uint32_t index; |
| if (key->AsArrayIndex(&index)) { |
| JSObject::SetOwnElement(json_object, index, value, kNonStrictMode); |
| } else if (key->Equals(isolate()->heap()->Proto_symbol())) { |
| SetPrototype(json_object, value); |
| } else { |
| JSObject::SetLocalPropertyIgnoreAttributes( |
| json_object, key, value, NONE); |
| } |
| } while (MatchSkipWhiteSpace(',')); |
| if (c0_ != '}') { |
| return ReportUnexpectedCharacter(); |
| } |
| } |
| AdvanceSkipWhitespace(); |
| return json_object; |
| } |
| |
| // Parse a JSON array. Position must be right at '['. |
| template <bool seq_ascii> |
| Handle<Object> JsonParser<seq_ascii>::ParseJsonArray() { |
| ZoneScope zone_scope(isolate(), DELETE_ON_EXIT); |
| ZoneList<Handle<Object> > elements(4); |
| ASSERT_EQ(c0_, '['); |
| |
| AdvanceSkipWhitespace(); |
| if (c0_ != ']') { |
| do { |
| Handle<Object> element = ParseJsonValue(); |
| if (element.is_null()) return ReportUnexpectedCharacter(); |
| elements.Add(element); |
| } while (MatchSkipWhiteSpace(',')); |
| if (c0_ != ']') { |
| return ReportUnexpectedCharacter(); |
| } |
| } |
| AdvanceSkipWhitespace(); |
| // Allocate a fixed array with all the elements. |
| Handle<FixedArray> fast_elements = |
| isolate()->factory()->NewFixedArray(elements.length()); |
| for (int i = 0, n = elements.length(); i < n; i++) { |
| fast_elements->set(i, *elements[i]); |
| } |
| return isolate()->factory()->NewJSArrayWithElements(fast_elements); |
| } |
| |
| |
| template <bool seq_ascii> |
| Handle<Object> JsonParser<seq_ascii>::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 ('0' <= c0_ && c0_ <= '9') 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 (c0_ >= '0' && c0_ <= '9'); |
| if (c0_ != '.' && c0_ != 'e' && c0_ != 'E' && digits < 10) { |
| SkipWhitespace(); |
| return Handle<Smi>(Smi::FromInt((negative ? -i : i)), isolate()); |
| } |
| } |
| if (c0_ == '.') { |
| Advance(); |
| if (c0_ < '0' || c0_ > '9') return ReportUnexpectedCharacter(); |
| do { |
| Advance(); |
| } while (c0_ >= '0' && c0_ <= '9'); |
| } |
| if (AsciiAlphaToLower(c0_) == 'e') { |
| Advance(); |
| if (c0_ == '-' || c0_ == '+') Advance(); |
| if (c0_ < '0' || c0_ > '9') return ReportUnexpectedCharacter(); |
| do { |
| Advance(); |
| } while (c0_ >= '0' && c0_ <= '9'); |
| } |
| int length = position_ - beg_pos; |
| double number; |
| if (seq_ascii) { |
| Vector<const char> chars(seq_source_->GetChars() + beg_pos, length); |
| number = StringToDouble(isolate()->unicode_cache(), |
| chars, |
| NO_FLAGS, // Hex, octal or trailing junk. |
| OS::nan_value()); |
| } else { |
| Vector<char> buffer = Vector<char>::New(length); |
| String::WriteToFlat(*source_, buffer.start(), beg_pos, position_); |
| Vector<const char> result = |
| Vector<const char>(reinterpret_cast<const char*>(buffer.start()), |
| length); |
| number = StringToDouble(isolate()->unicode_cache(), |
| result, |
| NO_FLAGS, // Hex, octal or trailing junk. |
| 0.0); |
| buffer.Dispose(); |
| } |
| SkipWhitespace(); |
| return isolate()->factory()->NewNumber(number); |
| } |
| |
| |
| 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<SeqAsciiString> seq_str, int i, uc32 c) { |
| seq_str->SeqAsciiStringSet(i, c); |
| } |
| |
| template <typename StringType> |
| inline Handle<StringType> NewRawString(Factory* factory, int length); |
| |
| template <> |
| inline Handle<SeqTwoByteString> NewRawString(Factory* factory, int length) { |
| return factory->NewRawTwoByteString(length, NOT_TENURED); |
| } |
| |
| template <> |
| inline Handle<SeqAsciiString> NewRawString(Factory* factory, int length) { |
| return factory->NewRawAsciiString(length, NOT_TENURED); |
| } |
| |
| |
| // 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_ascii> |
| template <typename StringType, typename SinkChar> |
| Handle<String> JsonParser<seq_ascii>::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_str = NewRawString<StringType>(isolate()->factory(), |
| length); |
| // Copy prefix into seq_str. |
| SinkChar* dest = seq_str->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_str, 0, count); |
| } |
| if (c0_ != '\\') { |
| // If the sink can contain UC16 characters, or source_ contains only |
| // ASCII characters, there's no need to test whether we can store the |
| // character. Otherwise check whether the UC16 source character can fit |
| // in the ASCII sink. |
| if (sizeof(SinkChar) == kUC16Size || |
| seq_ascii || |
| c0_ <= kMaxAsciiCharCode) { |
| SeqStringSet(seq_str, count++, c0_); |
| Advance(); |
| } else { |
| // StringType is SeqAsciiString and we just read a non-ASCII char. |
| return SlowScanJsonString<SeqTwoByteString, uc16>(seq_str, 0, count); |
| } |
| } else { |
| Advance(); // Advance past the \. |
| switch (c0_) { |
| case '"': |
| case '\\': |
| case '/': |
| SeqStringSet(seq_str, count++, c0_); |
| break; |
| case 'b': |
| SeqStringSet(seq_str, count++, '\x08'); |
| break; |
| case 'f': |
| SeqStringSet(seq_str, count++, '\x0c'); |
| break; |
| case 'n': |
| SeqStringSet(seq_str, count++, '\x0a'); |
| break; |
| case 'r': |
| SeqStringSet(seq_str, count++, '\x0d'); |
| break; |
| case 't': |
| SeqStringSet(seq_str, 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 <= kMaxAsciiCharCode) { |
| SeqStringSet(seq_str, count++, value); |
| break; |
| } else { |
| // StringType is SeqAsciiString and we just read a non-ASCII char. |
| position_ -= 6; // Rewind position_ to \ in \uxxxx. |
| Advance(); |
| return SlowScanJsonString<SeqTwoByteString, uc16>(seq_str, |
| 0, |
| count); |
| } |
| } |
| default: |
| return Handle<String>::null(); |
| } |
| Advance(); |
| } |
| } |
| // Shrink seq_string length to count. |
| if (isolate()->heap()->InNewSpace(*seq_str)) { |
| isolate()->heap()->new_space()-> |
| template ShrinkStringAtAllocationBoundary<StringType>( |
| *seq_str, count); |
| } else { |
| int string_size = StringType::SizeFor(count); |
| int allocated_string_size = StringType::SizeFor(length); |
| int delta = allocated_string_size - string_size; |
| Address start_filler_object = seq_str->address() + string_size; |
| seq_str->set_length(count); |
| isolate()->heap()->CreateFillerObjectAt(start_filler_object, delta); |
| } |
| ASSERT_EQ('"', c0_); |
| // Advance past the last '"'. |
| AdvanceSkipWhitespace(); |
| return seq_str; |
| } |
| |
| |
| template <bool seq_ascii> |
| template <bool is_symbol> |
| Handle<String> JsonParser<seq_ascii>::ScanJsonString() { |
| ASSERT_EQ('"', c0_); |
| Advance(); |
| if (c0_ == '"') { |
| AdvanceSkipWhitespace(); |
| return Handle<String>(isolate()->heap()->empty_string()); |
| } |
| int beg_pos = position_; |
| // Fast case for ASCII 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_ascii || c0_ <= kMaxAsciiCharCode) { |
| Advance(); |
| } else { |
| return SlowScanJsonString<SeqTwoByteString, uc16>(source_, |
| beg_pos, |
| position_); |
| } |
| } else { |
| return SlowScanJsonString<SeqAsciiString, char>(source_, |
| beg_pos, |
| position_); |
| } |
| } while (c0_ != '"'); |
| int length = position_ - beg_pos; |
| Handle<String> result; |
| if (seq_ascii && is_symbol) { |
| result = isolate()->factory()->LookupAsciiSymbol(seq_source_, |
| beg_pos, |
| length); |
| } else { |
| result = isolate()->factory()->NewRawAsciiString(length); |
| char* dest = SeqAsciiString::cast(*result)->GetChars(); |
| String::WriteToFlat(*source_, dest, beg_pos, position_); |
| } |
| ASSERT_EQ('"', c0_); |
| // Advance past the last '"'. |
| AdvanceSkipWhitespace(); |
| return result; |
| } |
| |
| } } // namespace v8::internal |
| |
| #endif // V8_JSON_PARSER_H_ |