Index: mojo/public/dart/third_party/analyzer/lib/src/generated/incremental_scanner.dart |
diff --git a/mojo/public/dart/third_party/analyzer/lib/src/generated/incremental_scanner.dart b/mojo/public/dart/third_party/analyzer/lib/src/generated/incremental_scanner.dart |
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index 0000000000000000000000000000000000000000..a2e4daf794d5eb12eefa8c59443b798ee8e0edda |
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@@ -0,0 +1,248 @@ |
+// Copyright (c) 2014, the Dart project authors. Please see the AUTHORS file |
+// for details. All rights reserved. Use of this source code is governed by a |
+// BSD-style license that can be found in the LICENSE file. |
+ |
+library engine.incremental_scanner; |
+ |
+import "dart:math" as math; |
+ |
+import 'package:analyzer/src/generated/engine.dart'; |
+ |
+import 'error.dart'; |
+import 'scanner.dart'; |
+import 'source.dart'; |
+import 'utilities_collection.dart' show TokenMap; |
+ |
+/** |
+ * An `IncrementalScanner` is a scanner that scans a subset of a string and |
+ * inserts the resulting tokens into the middle of an existing token stream. |
+ */ |
+class IncrementalScanner { |
+ /** |
+ * The source being scanned. |
+ */ |
+ final Source source; |
+ |
+ /** |
+ * The reader used to access the characters in the source. |
+ */ |
+ final CharacterReader reader; |
+ |
+ /** |
+ * The error listener that will be informed of any errors that are found |
+ * during the scan. |
+ * |
+ * TODO(brianwilkerson) Replace this with a list of errors so that we can |
+ * update the errors. |
+ */ |
+ final AnalysisErrorListener errorListener; |
+ |
+ final AnalysisOptions _options; |
+ |
+ /** |
+ * A map from tokens that were copied to the copies of the tokens. |
+ */ |
+ TokenMap _tokenMap = new TokenMap(); |
+ |
+ /** |
+ * The token immediately to the left of the range of tokens that were |
+ * modified. |
+ */ |
+ Token leftToken; |
+ |
+ /** |
+ * The token immediately to the right of the range of tokens that were |
+ * modified. |
+ */ |
+ Token rightToken; |
+ |
+ /** |
+ * A flag indicating whether there were any non-comment tokens changed (other |
+ * than having their position updated) as a result of the modification. |
+ */ |
+ bool hasNonWhitespaceChange = false; |
+ |
+ /** |
+ * Initialize a newly created scanner to scan characters within the given |
+ * [source]. The content of the source can be read using the given [reader]. |
+ * Any errors that are found will be reported to the given [errorListener]. |
+ * [_options] will determine how scanning is to be performed. |
+ */ |
+ IncrementalScanner( |
+ this.source, this.reader, this.errorListener, this._options); |
+ |
+ /** |
+ * Return a map from tokens that were copied to the copies of the tokens. |
+ * |
+ * @return a map from tokens that were copied to the copies of the tokens |
+ */ |
+ TokenMap get tokenMap => _tokenMap; |
+ |
+ /** |
+ * Given the [stream] of tokens scanned from the original source, the modified |
+ * source (the result of replacing one contiguous range of characters with |
+ * another string of characters), and a specification of the modification that |
+ * was made, update the token stream to reflect the modified source. Return |
+ * the first token in the updated token stream. |
+ * |
+ * The [stream] is expected to be the first non-EOF token in the token stream. |
+ * |
+ * The modification is specified by the [index] of the first character in both |
+ * the original and modified source that was affected by the modification, the |
+ * number of characters removed from the original source (the [removedLength]) |
+ * and the number of characters added to the modified source (the |
+ * [insertedLength]). |
+ */ |
+ Token rescan(Token stream, int index, int removedLength, int insertedLength) { |
+ Token leftEof = stream.previous; |
+ // |
+ // Compute the delta between the character index of characters after the |
+ // modified region in the original source and the index of the corresponding |
+ // character in the modified source. |
+ // |
+ int delta = insertedLength - removedLength; |
+ // |
+ // Skip past the tokens whose end is less than the replacement start. (If |
+ // the replacement start is equal to the end of an existing token, then it |
+ // means that the existing token might have been modified, so we need to |
+ // rescan it.) |
+ // |
+ while (stream.type != TokenType.EOF && stream.end < index) { |
+ _tokenMap.put(stream, stream); |
+ stream = stream.next; |
+ } |
+ Token oldFirst = stream; |
+ Token oldLeftToken = stream.previous; |
+ leftToken = oldLeftToken; |
+ // |
+ // Skip past tokens until we find a token whose offset is greater than the |
+ // end of the removed region. (If the end of the removed region is equal to |
+ // the beginning of an existing token, then it means that the existing token |
+ // might have been modified, so we need to rescan it.) |
+ // |
+ int removedEnd = index + (removedLength == 0 ? 0 : removedLength - 1); |
+ while (stream.type != TokenType.EOF && stream.offset <= removedEnd) { |
+ stream = stream.next; |
+ } |
+ // |
+ // Figure out which region of characters actually needs to be re-scanned. |
+ // |
+ Token oldLast; |
+ Token oldRightToken; |
+ if (stream.type != TokenType.EOF && removedEnd + 1 == stream.offset) { |
+ oldLast = stream; |
+ stream = stream.next; |
+ oldRightToken = stream; |
+ } else { |
+ oldLast = stream.previous; |
+ oldRightToken = stream; |
+ } |
+ // |
+ // Compute the range of characters that are known to need to be rescanned. |
+ // If the index is within an existing token, then we need to start at the |
+ // beginning of the token. |
+ // |
+ int scanStart = math.max(oldLeftToken.end, 0); |
+ int scanEnd = oldRightToken.offset + delta; |
+ // |
+ // Rescan the characters that need to be rescanned. |
+ // |
+ Token replacementStart = _scanRange(scanStart, scanEnd); |
+ oldLeftToken.setNext(replacementStart); |
+ Token replacementEnd = _findEof(replacementStart).previous; |
+ replacementEnd.setNext(stream); |
+ // |
+ // Apply the delta to the tokens after the last new token. |
+ // |
+ _updateOffsets(stream, delta); |
+ rightToken = stream; |
+ // |
+ // If the index is immediately after an existing token and the inserted |
+ // characters did not change that original token, then adjust the leftToken |
+ // to be the next token. For example, in "a; c;" --> "a;b c;", the leftToken |
+ // was ";", but this code advances it to "b" since "b" is the first new |
+ // token. |
+ // |
+ Token newFirst = leftToken.next; |
+ while (!identical(newFirst, rightToken) && |
+ !identical(oldFirst, oldRightToken) && |
+ newFirst.type != TokenType.EOF && |
+ _equalTokens(oldFirst, newFirst)) { |
+ _tokenMap.put(oldFirst, newFirst); |
+ oldLeftToken = oldFirst; |
+ oldFirst = oldFirst.next; |
+ leftToken = newFirst; |
+ newFirst = newFirst.next; |
+ } |
+ Token newLast = rightToken.previous; |
+ while (!identical(newLast, leftToken) && |
+ !identical(oldLast, oldLeftToken) && |
+ newLast.type != TokenType.EOF && |
+ _equalTokens(oldLast, newLast)) { |
+ _tokenMap.put(oldLast, newLast); |
+ oldRightToken = oldLast; |
+ oldLast = oldLast.previous; |
+ rightToken = newLast; |
+ newLast = newLast.previous; |
+ } |
+ hasNonWhitespaceChange = !identical(leftToken.next, rightToken) || |
+ !identical(oldLeftToken.next, oldRightToken); |
+ // |
+ // TODO(brianwilkerson) Begin tokens are not getting associated with the |
+ // corresponding end tokens (because the end tokens have not been copied |
+ // when we're copying the begin tokens). This could have implications for |
+ // parsing. |
+ // TODO(brianwilkerson) Update the lineInfo. |
+ // |
+ return leftEof.next; |
+ } |
+ |
+ /** |
+ * Return `true` if the [oldToken] and the [newToken] are equal to each other. |
+ * For the purposes of the incremental scanner, two tokens are equal if they |
+ * have the same type and lexeme. |
+ */ |
+ bool _equalTokens(Token oldToken, Token newToken) => |
+ oldToken.type == newToken.type && |
+ oldToken.length == newToken.length && |
+ oldToken.lexeme == newToken.lexeme; |
+ |
+ /** |
+ * Given a [token], return the EOF token that follows the token. |
+ */ |
+ Token _findEof(Token token) { |
+ while (token.type != TokenType.EOF) { |
+ token = token.next; |
+ } |
+ return token; |
+ } |
+ |
+ /** |
+ * Scan the token between the [start] (inclusive) and [end] (exclusive) |
+ * offsets. |
+ */ |
+ Token _scanRange(int start, int end) { |
+ Scanner scanner = new Scanner( |
+ source, new CharacterRangeReader(reader, start, end), errorListener); |
+ return scanner.tokenize(); |
+ } |
+ |
+ /** |
+ * Update the offsets of every token from the given [token] to the end of the |
+ * stream by adding the given [delta]. |
+ */ |
+ void _updateOffsets(Token token, int delta) { |
+ while (token.type != TokenType.EOF) { |
+ _tokenMap.put(token, token); |
+ token.offset += delta; |
+ Token comment = token.precedingComments; |
+ while (comment != null) { |
+ comment.offset += delta; |
+ comment = comment.next; |
+ } |
+ token = token.next; |
+ } |
+ _tokenMap.put(token, token); |
+ token.offset += delta; |
+ } |
+} |