Linter Demo

Errors: 0

Warnings: 6

File: /home/fstrocco/Dart/dart/benchmark/compiler/lib/src/string_validator.dart

// Copyright (c) 2012, 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. // Check the validity of string literals. library stringvalidator; import "dart:collection"; import "dart2jslib.dart"; import "tree/tree.dart"; import "util/characters.dart"; import "scanner/scannerlib.dart" show Token; class StringValidator { final DiagnosticListener listener; StringValidator(this.listener); DartString validateInterpolationPart(Token token, StringQuoting quoting, {bool isFirst: false, bool isLast: false}) { String source = token.value; int leftQuote = 0; int rightQuote = 0; if (isFirst) leftQuote = quoting.leftQuoteLength; if (isLast) rightQuote = quoting.rightQuoteLength; String content = copyWithoutQuotes(source, leftQuote, rightQuote); return validateString(token, token.charOffset + leftQuote, content, quoting); } static StringQuoting quotingFromString(String sourceString) { Iterator<int> source = sourceString.codeUnits.iterator; bool raw = false; int leftQuoteLength = 1; source.moveNext(); int quoteChar = source.current; if (quoteChar == $r) { raw = true; source.moveNext(); quoteChar = source.current; } assert(quoteChar == $SQ || quoteChar == $DQ); // String has at least one quote. Check it if has three. // If it only has two, the string must be an empty string literal, // and end after the second quote. bool multiline = false; if (source.moveNext() && source.current == quoteChar && source.moveNext()) { int code = source.current; assert(code == quoteChar); // If not, there is a bug in the parser. leftQuoteLength = 3; // Check if a multiline string starts with optional whitespace followed by // a newline (CR, LF or CR+LF). // We also accept if the these characters are escaped by a backslash. int newLineLength = 1; while (true) { // Due to string-interpolations we are not guaranteed to see the // trailing quoting characters. The invocations to `moveNext()` may // therefore return false and the `current`-getter return `null`. The // code does not need to handle this specially (as it will not find the // newline characters). source.moveNext(); code = source.current; if (code == $BACKSLASH) { newLineLength++; source.moveNext(); code = source.current; } if (code == $TAB || code == $SPACE) { newLineLength++; continue; } if (code == $CR) { if (source.moveNext() && source.current == $LF) { newLineLength++; } leftQuoteLength += newLineLength; } else if (code == $LF) { leftQuoteLength += newLineLength; } break; } } return StringQuoting.getQuoting(quoteChar, raw, leftQuoteLength); } /** * Return the string [string] witout its [initial] first and [terminal] last * characters. This is intended to be used to remove quotes from string * literals (including an initial 'r' for raw strings). */ String copyWithoutQuotes(String string, int initial, int terminal) { assert(0 <= initial); assert(0 <= terminal); assert(initial + terminal <= string.length); return string.substring(initial, string.length - terminal); } void stringParseError(String message, Token token, int offset) { listener.reportError( token, MessageKind.GENERIC, {'text': "$message @ $offset"}); } /** * Validates the escape sequences and special characters of a string literal. * Returns a DartString if valid, and null if not. */ DartString validateString(Token token, int startOffset, String string, StringQuoting quoting) { // We need to check for invalid x and u escapes, for line // terminators in non-multiline strings, and for invalid Unicode // scalar values (either directly or as u-escape values). We also check // for unpaired UTF-16 surrogates. int length = 0; int index = startOffset; bool containsEscape = false; bool previousWasLeadSurrogate = false; bool invalidUtf16 = false; var stringIter = string.codeUnits.iterator; for(HasNextIterator<int> iter = new HasNextIterator(stringIter); iter.hasNext; length++) { index++; int code = iter.next(); if (code == $BACKSLASH) { if (quoting.raw) continue; containsEscape = true; if (!iter.hasNext) { stringParseError("Incomplete escape sequence",token, index); return null; } index++; code = iter.next(); if (code == $x) { for (int i = 0; i < 2; i++) { if (!iter.hasNext) { stringParseError("Incomplete escape sequence", token, index); return null; } index++; code = iter.next(); if (!isHexDigit(code)) { stringParseError("Invalid character in escape sequence", token, index); return null; } } // A two-byte hex escape can't generate an invalid value. continue; } else if (code == $u) { int escapeStart = index - 1; index++; code = iter.hasNext ? iter.next() : 0; int value = 0; if (code == $OPEN_CURLY_BRACKET) { // expect 1-6 hex digits. int count = 0; while (iter.hasNext) { code = iter.next(); index++; if (code == $CLOSE_CURLY_BRACKET) { break; } if (!isHexDigit(code)) { stringParseError("Invalid character in escape sequence", token, index); return null; } count++; value = value * 16 + hexDigitValue(code); } if (code != $CLOSE_CURLY_BRACKET || count == 0 || count > 6) { int errorPosition = index - count; if (count > 6) errorPosition += 6; stringParseError("Invalid character in escape sequence", token, errorPosition); return null; } } else { // Expect four hex digits, including the one just read. for (int i = 0; i < 4; i++) { if (i > 0) { if (iter.hasNext) { index++; code = iter.next(); } else { code = 0; } } if (!isHexDigit(code)) { stringParseError("Invalid character in escape sequence", token, index); return null; } value = value * 16 + hexDigitValue(code); } } code = value; } } if (code >= 0x10000) length++; // This handles both unescaped characters and the value of unicode // escapes. if (previousWasLeadSurrogate) { if (!isUtf16TrailSurrogate(code)) { invalidUtf16 = true; break; } previousWasLeadSurrogate = false; } else if (isUtf16LeadSurrogate(code)) { previousWasLeadSurrogate = true; } else if (!isUnicodeScalarValue(code)) { invalidUtf16 = true; break; } } if (previousWasLeadSurrogate || invalidUtf16) { stringParseError("Invalid Utf16 surrogate", token, index); return null; } // String literal successfully validated. if (quoting.raw || !containsEscape) { // A string without escapes could just as well have been raw. return new DartString.rawString(string, length); } return new DartString.escapedString(string, length); } }