| OLD | NEW |
|---|
| (Empty) |
| 1 // Copyright (c) 2014, the Dart project authors. Please see the AUTHORS file | |
| 2 // for details. All rights reserved. Use of this source code is governed by a | |
| 3 // BSD-style license that can be found in the LICENSE file. | |
| 4 | |
| 5 library engine.incremental_scanner; | |
| 6 | |
| 7 import "dart:math" as math; | |
| 8 | |
| 9 import 'package:analyzer/src/generated/engine.dart'; | |
| 10 | |
| 11 import 'error.dart'; | |
| 12 import 'scanner.dart'; | |
| 13 import 'source.dart'; | |
| 14 import 'utilities_collection.dart' show TokenMap; | |
| 15 | |
| 16 /** | |
| 17 * An `IncrementalScanner` is a scanner that scans a subset of a string and | |
| 18 * inserts the resulting tokens into the middle of an existing token stream. | |
| 19 */ | |
| 20 class IncrementalScanner { | |
| 21 /** | |
| 22 * The source being scanned. | |
| 23 */ | |
| 24 final Source source; | |
| 25 | |
| 26 /** | |
| 27 * The reader used to access the characters in the source. | |
| 28 */ | |
| 29 final CharacterReader reader; | |
| 30 | |
| 31 /** | |
| 32 * The error listener that will be informed of any errors that are found | |
| 33 * during the scan. | |
| 34 * | |
| 35 * TODO(brianwilkerson) Replace this with a list of errors so that we can | |
| 36 * update the errors. | |
| 37 */ | |
| 38 final AnalysisErrorListener errorListener; | |
| 39 | |
| 40 final AnalysisOptions _options; | |
| 41 | |
| 42 /** | |
| 43 * A map from tokens that were copied to the copies of the tokens. | |
| 44 */ | |
| 45 TokenMap _tokenMap = new TokenMap(); | |
| 46 | |
| 47 /** | |
| 48 * The token immediately to the left of the range of tokens that were | |
| 49 * modified. | |
| 50 */ | |
| 51 Token leftToken; | |
| 52 | |
| 53 /** | |
| 54 * The token immediately to the right of the range of tokens that were | |
| 55 * modified. | |
| 56 */ | |
| 57 Token rightToken; | |
| 58 | |
| 59 /** | |
| 60 * A flag indicating whether there were any non-comment tokens changed (other | |
| 61 * than having their position updated) as a result of the modification. | |
| 62 */ | |
| 63 bool hasNonWhitespaceChange = false; | |
| 64 | |
| 65 /** | |
| 66 * Initialize a newly created scanner to scan characters within the given | |
| 67 * [source]. The content of the source can be read using the given [reader]. | |
| 68 * Any errors that are found will be reported to the given [errorListener]. | |
| 69 * [_options] will determine how scanning is to be performed. | |
| 70 */ | |
| 71 IncrementalScanner( | |
| 72 this.source, this.reader, this.errorListener, this._options); | |
| 73 | |
| 74 /** | |
| 75 * Return a map from tokens that were copied to the copies of the tokens. | |
| 76 * | |
| 77 * @return a map from tokens that were copied to the copies of the tokens | |
| 78 */ | |
| 79 TokenMap get tokenMap => _tokenMap; | |
| 80 | |
| 81 /** | |
| 82 * Given the [stream] of tokens scanned from the original source, the modified | |
| 83 * source (the result of replacing one contiguous range of characters with | |
| 84 * another string of characters), and a specification of the modification that | |
| 85 * was made, update the token stream to reflect the modified source. Return | |
| 86 * the first token in the updated token stream. | |
| 87 * | |
| 88 * The [stream] is expected to be the first non-EOF token in the token stream. | |
| 89 * | |
| 90 * The modification is specified by the [index] of the first character in both | |
| 91 * the original and modified source that was affected by the modification, the | |
| 92 * number of characters removed from the original source (the [removedLength]) | |
| 93 * and the number of characters added to the modified source (the | |
| 94 * [insertedLength]). | |
| 95 */ | |
| 96 Token rescan(Token stream, int index, int removedLength, int insertedLength) { | |
| 97 Token leftEof = stream.previous; | |
| 98 // | |
| 99 // Compute the delta between the character index of characters after the | |
| 100 // modified region in the original source and the index of the corresponding | |
| 101 // character in the modified source. | |
| 102 // | |
| 103 int delta = insertedLength - removedLength; | |
| 104 // | |
| 105 // Skip past the tokens whose end is less than the replacement start. (If | |
| 106 // the replacement start is equal to the end of an existing token, then it | |
| 107 // means that the existing token might have been modified, so we need to | |
| 108 // rescan it.) | |
| 109 // | |
| 110 while (stream.type != TokenType.EOF && stream.end < index) { | |
| 111 _tokenMap.put(stream, stream); | |
| 112 stream = stream.next; | |
| 113 } | |
| 114 Token oldFirst = stream; | |
| 115 Token oldLeftToken = stream.previous; | |
| 116 leftToken = oldLeftToken; | |
| 117 // | |
| 118 // Skip past tokens until we find a token whose offset is greater than the | |
| 119 // end of the removed region. (If the end of the removed region is equal to | |
| 120 // the beginning of an existing token, then it means that the existing token | |
| 121 // might have been modified, so we need to rescan it.) | |
| 122 // | |
| 123 int removedEnd = index + (removedLength == 0 ? 0 : removedLength - 1); | |
| 124 while (stream.type != TokenType.EOF && stream.offset <= removedEnd) { | |
| 125 stream = stream.next; | |
| 126 } | |
| 127 // | |
| 128 // Figure out which region of characters actually needs to be re-scanned. | |
| 129 // | |
| 130 Token oldLast; | |
| 131 Token oldRightToken; | |
| 132 if (stream.type != TokenType.EOF && removedEnd + 1 == stream.offset) { | |
| 133 oldLast = stream; | |
| 134 stream = stream.next; | |
| 135 oldRightToken = stream; | |
| 136 } else { | |
| 137 oldLast = stream.previous; | |
| 138 oldRightToken = stream; | |
| 139 } | |
| 140 // | |
| 141 // Compute the range of characters that are known to need to be rescanned. | |
| 142 // If the index is within an existing token, then we need to start at the | |
| 143 // beginning of the token. | |
| 144 // | |
| 145 int scanStart = math.max(oldLeftToken.end, 0); | |
| 146 int scanEnd = oldRightToken.offset + delta; | |
| 147 // | |
| 148 // Rescan the characters that need to be rescanned. | |
| 149 // | |
| 150 Token replacementStart = _scanRange(scanStart, scanEnd); | |
| 151 oldLeftToken.setNext(replacementStart); | |
| 152 Token replacementEnd = _findEof(replacementStart).previous; | |
| 153 replacementEnd.setNext(stream); | |
| 154 // | |
| 155 // Apply the delta to the tokens after the last new token. | |
| 156 // | |
| 157 _updateOffsets(stream, delta); | |
| 158 rightToken = stream; | |
| 159 // | |
| 160 // If the index is immediately after an existing token and the inserted | |
| 161 // characters did not change that original token, then adjust the leftToken | |
| 162 // to be the next token. For example, in "a; c;" --> "a;b c;", the leftToken | |
| 163 // was ";", but this code advances it to "b" since "b" is the first new | |
| 164 // token. | |
| 165 // | |
| 166 Token newFirst = leftToken.next; | |
| 167 while (!identical(newFirst, rightToken) && | |
| 168 !identical(oldFirst, oldRightToken) && | |
| 169 newFirst.type != TokenType.EOF && | |
| 170 _equalTokens(oldFirst, newFirst)) { | |
| 171 _tokenMap.put(oldFirst, newFirst); | |
| 172 oldLeftToken = oldFirst; | |
| 173 oldFirst = oldFirst.next; | |
| 174 leftToken = newFirst; | |
| 175 newFirst = newFirst.next; | |
| 176 } | |
| 177 Token newLast = rightToken.previous; | |
| 178 while (!identical(newLast, leftToken) && | |
| 179 !identical(oldLast, oldLeftToken) && | |
| 180 newLast.type != TokenType.EOF && | |
| 181 _equalTokens(oldLast, newLast)) { | |
| 182 _tokenMap.put(oldLast, newLast); | |
| 183 oldRightToken = oldLast; | |
| 184 oldLast = oldLast.previous; | |
| 185 rightToken = newLast; | |
| 186 newLast = newLast.previous; | |
| 187 } | |
| 188 hasNonWhitespaceChange = !identical(leftToken.next, rightToken) || | |
| 189 !identical(oldLeftToken.next, oldRightToken); | |
| 190 // | |
| 191 // TODO(brianwilkerson) Begin tokens are not getting associated with the | |
| 192 // corresponding end tokens (because the end tokens have not been copied | |
| 193 // when we're copying the begin tokens). This could have implications for | |
| 194 // parsing. | |
| 195 // TODO(brianwilkerson) Update the lineInfo. | |
| 196 // | |
| 197 return leftEof.next; | |
| 198 } | |
| 199 | |
| 200 /** | |
| 201 * Return `true` if the [oldToken] and the [newToken] are equal to each other. | |
| 202 * For the purposes of the incremental scanner, two tokens are equal if they | |
| 203 * have the same type and lexeme. | |
| 204 */ | |
| 205 bool _equalTokens(Token oldToken, Token newToken) => | |
| 206 oldToken.type == newToken.type && | |
| 207 oldToken.length == newToken.length && | |
| 208 oldToken.lexeme == newToken.lexeme; | |
| 209 | |
| 210 /** | |
| 211 * Given a [token], return the EOF token that follows the token. | |
| 212 */ | |
| 213 Token _findEof(Token token) { | |
| 214 while (token.type != TokenType.EOF) { | |
| 215 token = token.next; | |
| 216 } | |
| 217 return token; | |
| 218 } | |
| 219 | |
| 220 /** | |
| 221 * Scan the token between the [start] (inclusive) and [end] (exclusive) | |
| 222 * offsets. | |
| 223 */ | |
| 224 Token _scanRange(int start, int end) { | |
| 225 Scanner scanner = new Scanner( | |
| 226 source, new CharacterRangeReader(reader, start, end), errorListener); | |
| 227 return scanner.tokenize(); | |
| 228 } | |
| 229 | |
| 230 /** | |
| 231 * Update the offsets of every token from the given [token] to the end of the | |
| 232 * stream by adding the given [delta]. | |
| 233 */ | |
| 234 void _updateOffsets(Token token, int delta) { | |
| 235 while (token.type != TokenType.EOF) { | |
| 236 _tokenMap.put(token, token); | |
| 237 token.offset += delta; | |
| 238 Token comment = token.precedingComments; | |
| 239 while (comment != null) { | |
| 240 comment.offset += delta; | |
| 241 comment = comment.next; | |
| 242 } | |
| 243 token = token.next; | |
| 244 } | |
| 245 _tokenMap.put(token, token); | |
| 246 token.offset += delta; | |
| 247 } | |
| 248 } | |
| OLD | NEW |
|---|
Chromium Code Reviews
Issue 2990843002:
Removed fixed dependencies (Closed)
