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Unified Diff: pkg/compiler/lib/src/scanner/utf8_bytes_scanner.dart

Issue 2644843006: Use packages dart_parser, dart_scanner, and compiler_util. (Closed)
Patch Set: Created 3 years, 11 months ago
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Index: pkg/compiler/lib/src/scanner/utf8_bytes_scanner.dart
diff --git a/pkg/compiler/lib/src/scanner/utf8_bytes_scanner.dart b/pkg/compiler/lib/src/scanner/utf8_bytes_scanner.dart
deleted file mode 100644
index ea46e35457c8ed133b82c176a63d0a9b841a4f5f..0000000000000000000000000000000000000000
--- a/pkg/compiler/lib/src/scanner/utf8_bytes_scanner.dart
+++ /dev/null
@@ -1,214 +0,0 @@
-// Copyright (c) 2013, 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 dart2js.scanner.utf8;
-
-import 'dart:convert' show UNICODE_BOM_CHARACTER_RUNE, UTF8;
-
-import '../io/source_file.dart' show SourceFile;
-import '../tokens/precedence.dart' show PrecedenceInfo;
-import '../tokens/token.dart' show StringToken, Token;
-import 'array_based_scanner.dart' show ArrayBasedScanner;
-
-/**
- * Scanner that reads from a UTF-8 encoded list of bytes and creates tokens
- * that points to substrings.
- */
-class Utf8BytesScanner extends ArrayBasedScanner {
- /**
- * The file content.
- *
- * The content is zero-terminated.
- */
- List<int> bytes;
-
- /**
- * Points to the offset of the last byte returned by [advance].
- *
- * After invoking [currentAsUnicode], the [byteOffset] points to the last
- * byte that is part of the (unicode or ASCII) character. That way, [advance]
- * can always increase the byte offset by 1.
- */
- int byteOffset = -1;
-
- /**
- * The getter [scanOffset] is expected to return the index where the current
- * character *starts*. In case of a non-ascii character, after invoking
- * [currentAsUnicode], the byte offset points to the *last* byte.
- *
- * This field keeps track of the number of bytes for the current unicode
- * character. For example, if bytes 7,8,9 encode one unicode character, the
- * [byteOffset] is 9 (after invoking [currentAsUnicode]). The [scanSlack]
- * will be 2, so that [scanOffset] returns 7.
- */
- int scanSlack = 0;
-
- /**
- * Holds the [byteOffset] value for which the current [scanSlack] is valid.
- */
- int scanSlackOffset = -1;
-
- /**
- * Returns the byte offset of the first byte that belongs to the current
- * character.
- */
- int get scanOffset {
- if (byteOffset == scanSlackOffset) {
- return byteOffset - scanSlack;
- } else {
- return byteOffset;
- }
- }
-
- /**
- * The difference between the number of bytes and the number of corresponding
- * string characters, up to the current [byteOffset].
- */
- int utf8Slack = 0;
-
- /**
- * Creates a new Utf8BytesScanner. The source file is expected to be a
- * [Utf8BytesSourceFile] that holds a list of UTF-8 bytes. Otherwise the
- * string text of the source file is decoded.
- *
- * The list of UTF-8 bytes [file.slowUtf8Bytes()] is expected to return an
- * array whose last element is '0' to signal the end of the file. If this
- * is not the case, the entire array is copied before scanning.
- */
- Utf8BytesScanner(SourceFile file, {bool includeComments: false})
- : bytes = file.slowUtf8ZeroTerminatedBytes(),
- super(file, includeComments) {
- assert(bytes.last == 0);
- // Skip a leading BOM.
- if (_containsBomAt(0)) byteOffset += 3;
- }
-
- /**
- * Creates a new Utf8BytesScanner from a list of UTF-8 bytes.
- *
- * The last element of the list is expected to be '0' to signal the end of
- * the file. If this is not the case, the entire array is copied before
- * scanning.
- */
- Utf8BytesScanner.fromBytes(List<int> zeroTerminatedBytes,
- {bool includeComments: false})
- : this.bytes = zeroTerminatedBytes,
- super(null, includeComments) {
- assert(bytes.last == 0);
- }
-
- bool _containsBomAt(int offset) {
- const BOM_UTF8 = const [0xEF, 0xBB, 0xBF];
-
- return offset + 3 < bytes.length &&
- bytes[offset] == BOM_UTF8[0] &&
- bytes[offset + 1] == BOM_UTF8[1] &&
- bytes[offset + 2] == BOM_UTF8[2];
- }
-
- int advance() => bytes[++byteOffset];
-
- int peek() => bytes[byteOffset + 1];
-
- /**
- * Returns the unicode code point starting at the byte offset [startOffset]
- * with the byte [nextByte]. If [advance] is true the current [byteOffset]
- * is advanced to the last byte of the code point.
- */
- int nextCodePoint(int startOffset, int nextByte, bool advance) {
- // The number of 1s in the first byte indicate the number of bytes, at
- // least 2.
- int numBytes = 2;
- int bit = 0x20;
- while ((nextByte & bit) != 0) {
- numBytes++;
- bit >>= 1;
- }
- int end = startOffset + numBytes;
- if (advance) {
- byteOffset = end - 1;
- }
- // TODO(lry): measurably slow, decode creates first a Utf8Decoder and a
- // _Utf8Decoder instance. Also the sublist is eagerly allocated.
- String codePoint = UTF8.decode(bytes.sublist(startOffset, end));
- if (codePoint.length == 0) {
- // The UTF-8 decoder discards leading BOM characters.
- // TODO(floitsch): don't just assume that removed characters were the
- // BOM.
- assert(_containsBomAt(startOffset));
- codePoint = new String.fromCharCode(UNICODE_BOM_CHARACTER_RUNE);
- }
- if (codePoint.length == 1) {
- if (advance) {
- utf8Slack += (numBytes - 1);
- scanSlack = numBytes - 1;
- scanSlackOffset = byteOffset;
- }
- return codePoint.codeUnitAt(0);
- } else if (codePoint.length == 2) {
- if (advance) {
- utf8Slack += (numBytes - 2);
- scanSlack = numBytes - 1;
- scanSlackOffset = byteOffset;
- stringOffsetSlackOffset = byteOffset;
- }
- // In case of a surrogate pair, return a single code point.
- return codePoint.runes.single;
- } else {
- throw "Invalid UTF-8 byte sequence: ${bytes.sublist(startOffset, end)}";
- }
- }
-
- int lastUnicodeOffset = -1;
- int currentAsUnicode(int next) {
- if (next < 128) return next;
- // Check if currentAsUnicode was already invoked.
- if (byteOffset == lastUnicodeOffset) return next;
- int res = nextCodePoint(byteOffset, next, true);
- lastUnicodeOffset = byteOffset;
- return res;
- }
-
- void handleUnicode(int startScanOffset) {
- int end = byteOffset;
- // TODO(lry): this measurably slows down the scanner for files with unicode.
- String s = UTF8.decode(bytes.sublist(startScanOffset, end));
- utf8Slack += (end - startScanOffset) - s.length;
- }
-
- /**
- * This field remembers the byte offset of the last character decoded with
- * [nextCodePoint] that used two code units in UTF-16.
- *
- * [nextCodePoint] returns a single code point for each unicode character,
- * even if it needs two code units in UTF-16.
- *
- * For example, '\u{1d11e}' uses 4 bytes in UTF-8, and two code units in
- * UTF-16. The [utf8Slack] is therefore 2. After invoking [nextCodePoint], the
- * [byteOffset] points to the last (of 4) bytes. The [stringOffset] should
- * return the offset of the first one, which is one position more left than
- * the [utf8Slack].
- */
- int stringOffsetSlackOffset = -1;
-
- int get stringOffset {
- if (stringOffsetSlackOffset == byteOffset) {
- return byteOffset - utf8Slack - 1;
- } else {
- return byteOffset - utf8Slack;
- }
- }
-
- Token firstToken() => tokens.next;
- Token previousToken() => tail;
-
- void appendSubstringToken(PrecedenceInfo info, int start, bool asciiOnly,
- [int extraOffset = 0]) {
- tail.next = new StringToken.fromUtf8Bytes(
- info, bytes, start, byteOffset + extraOffset, asciiOnly, tokenStart);
- tail = tail.next;
- }
-
- bool atEndOfFile() => byteOffset >= bytes.length - 1;
-}

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