1 /* 2 * Copyright 2017-2021 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license. 3 */ 4 5 package kotlinx.serialization.json.internal 6 7 internal class StringJsonLexer(override val source: String) : AbstractJsonLexer() { 8 prefetchOrEofnull9 override fun prefetchOrEof(position: Int): Int = if (position < source.length) position else -1 10 11 override fun consumeNextToken(): Byte { 12 val source = source 13 while (currentPosition != -1 && currentPosition < source.length) { 14 val ch = source[currentPosition++] 15 return when (val tc = charToTokenClass(ch)) { 16 TC_WHITESPACE -> continue 17 else -> tc 18 } 19 } 20 return TC_EOF 21 } 22 tryConsumeCommanull23 override fun tryConsumeComma(): Boolean { 24 val current = skipWhitespaces() 25 if (current == source.length || current == -1) return false 26 if (source[current] == ',') { 27 ++currentPosition 28 return true 29 } 30 return false 31 } 32 canConsumeValuenull33 override fun canConsumeValue(): Boolean { 34 var current = currentPosition 35 if (current == -1) return false 36 while (current < source.length) { 37 val c = source[current] 38 // Inlined skipWhitespaces without field spill and nested loop. Also faster then char2TokenClass 39 if (c == ' ' || c == '\n' || c == '\r' || c == '\t') { 40 ++current 41 continue 42 } 43 currentPosition = current 44 return isValidValueStart(c) 45 } 46 currentPosition = current 47 return false 48 } 49 skipWhitespacesnull50 override fun skipWhitespaces(): Int { 51 var current = currentPosition 52 if (current == -1) return current 53 // Skip whitespaces 54 while (current < source.length) { 55 val c = source[current] 56 // Faster than char2TokenClass actually 57 if (c == ' ' || c == '\n' || c == '\r' || c == '\t') { 58 ++current 59 } else { 60 break 61 } 62 } 63 currentPosition = current 64 return current 65 } 66 consumeNextTokennull67 override fun consumeNextToken(expected: Char) { 68 if (currentPosition == -1) unexpectedToken(expected) 69 val source = source 70 while (currentPosition < source.length) { 71 val c = source[currentPosition++] 72 if (c == ' ' || c == '\n' || c == '\r' || c == '\t') continue 73 if (c == expected) return 74 unexpectedToken(expected) 75 } 76 currentPosition = -1 // for correct EOF reporting 77 unexpectedToken(expected) // EOF 78 } 79 consumeKeyStringnull80 override fun consumeKeyString(): String { 81 /* 82 * For strings we assume that escaped symbols are rather an exception, so firstly 83 * we optimistically scan for closing quote via intrinsified and blazing-fast 'indexOf', 84 * than do our pessimistic check for backslash and fallback to slow-path if necessary. 85 */ 86 consumeNextToken(STRING) 87 val current = currentPosition 88 val closingQuote = source.indexOf('"', current) 89 if (closingQuote == -1) { 90 // advance currentPosition to a token after the end of the string to guess position in the error msg 91 // (not always correct, as `:`/`,` are valid contents of the string, but good guess anyway) 92 consumeStringLenient() 93 fail(TC_STRING, wasConsumed = false) 94 } 95 // Now we _optimistically_ know where the string ends (it might have been an escaped quote) 96 for (i in current until closingQuote) { 97 // Encountered escape sequence, should fallback to "slow" path and symbolic scanning 98 if (source[i] == STRING_ESC) { 99 return consumeString(source, currentPosition, i) 100 } 101 } 102 this.currentPosition = closingQuote + 1 103 return source.substring(current, closingQuote) 104 } 105 consumeStringChunkednull106 override fun consumeStringChunked(isLenient: Boolean, consumeChunk: (stringChunk: String) -> Unit) { 107 (if (isLenient) consumeStringLenient() else consumeString()).chunked(BATCH_SIZE).forEach(consumeChunk) 108 } 109 peekLeadingMatchingValuenull110 override fun peekLeadingMatchingValue(keyToMatch: String, isLenient: Boolean): String? { 111 val positionSnapshot = currentPosition 112 try { 113 if (consumeNextToken() != TC_BEGIN_OBJ) return null // Malformed JSON, bailout 114 val firstKey = peekString(isLenient) 115 if (firstKey != keyToMatch) return null 116 discardPeeked() // consume firstKey 117 if (consumeNextToken() != TC_COLON) return null 118 return peekString(isLenient) 119 } finally { 120 // Restore the position 121 currentPosition = positionSnapshot 122 discardPeeked() 123 } 124 } 125 } 126 127