Move frog/leg to lib/compiler/implementation.

frog/leg/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("leg.dart");
-#import("scanner/scannerlib.dart");
-#import("tree/tree.dart");
-#import("elements/elements.dart");
-#import("util/characters.dart");
-
-class StringValidator  {
-  final DiagnosticListener listener;
-
-  StringValidator(this.listener);
-
-  DartString validateQuotedString(Token token) {
-    SourceString source = token.value;
-    StringQuoting quoting = quotingFromString(source);
-    int leftQuote = quoting.leftQuoteLength;
-    int rightQuote = quoting.rightQuoteLength;
-    SourceString content = source.copyWithoutQuotes(leftQuote, rightQuote);
-    return validateString(token,
-                          token.charOffset + leftQuote,
-                          content,
-                          quoting);
-  }
-
-  DartString validateInterpolationPart(Token token, StringQuoting quoting,
-                                       [bool isFirst = false,
-                                        bool isLast = false]) {
-    SourceString source = token.value;
-    int leftQuote = 0;
-    int rightQuote = 0;
-    if (isFirst) leftQuote = quoting.leftQuoteLength;
-    if (isLast) rightQuote = quoting.rightQuoteLength;
-    SourceString content = source.copyWithoutQuotes(leftQuote, rightQuote);
-    return validateString(token,
-                          token.charOffset + leftQuote,
-                          content,
-                          quoting);
-  }
-
-  static StringQuoting quotingFromString(SourceString sourceString) {
-    Iterator<int> source = sourceString.iterator();
-    bool raw = false;
-    int quoteLength = 1;
-    int quoteChar = source.next();
-    if (quoteChar == $AT) {
-      raw = true;
-      quoteChar = source.next();
-    }
-    assert(quoteChar === $SQ || quoteChar === $DQ);
-    // String has at least one quote. Check it if has three.
-    // If it only have two, the string must be an empty string literal,
-    // and end after the second quote.
-    bool multiline = false;
-    if (source.hasNext() && source.next() === quoteChar && source.hasNext()) {
-      int code = source.next();
-      assert(code === quoteChar);  // If not, there is a bug in the parser.
-      quoteLength = 3;
-      // Check if a multiline string starts with a newline (CR, LF or CR+LF).
-      if (source.hasNext()) {
-        code = source.next();
-        if (code === $CR) {
-          quoteLength += 1;
-          if (source.hasNext() && source.next() === $LF) {
-            quoteLength += 1;
-          }
-        } else if (code === $LF) {
-          quoteLength += 1;
-        }
-      }
-    }
-    return StringQuoting.getQuoting(quoteChar, raw, quoteLength);
-  }
-
-  void stringParseError(String message, Token token, int offset) {
-    listener.cancel("$message @ $offset", token : token);
-  }
-
-  /**
-   * 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,
-                            SourceString string,
-                            StringQuoting quoting) {
-    // We only 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).
-    int length = 0;
-    int index = startOffset;
-    bool containsEscape = false;
-    for(Iterator<int> iter = string.iterator(); 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.next();
-          int value = 0;
-          if (code == $OPEN_CURLY_BRACKET) {
-            // expect 1-6 hex digits.
-            int count = 0;
-            index++;
-            code = iter.next();
-            do {
-              if (!isHexDigit(code)) {
-                stringParseError("Invalid character in escape sequence",
-                                 token, index);
-                return null;
-              }
-              count++;
-              value = value * 16 + hexDigitValue(code);
-              index++;
-              code = iter.next();
-            } while (code != $CLOSE_CURLY_BRACKET);
-            if (count > 6) {
-              stringParseError("Invalid character in escape sequence",
-                               token, index - (count - 6));
-              return null;
-            }
-          } else {
-            // Expect four hex digits, including the one just read.
-            for (int i = 0; i < 4; i++) {
-              if (i > 0) {
-                index++;
-                code = iter.next();
-              }
-              if (!isHexDigit(code)) {
-                stringParseError("Invalid character in escape sequence",
-                                 token, index);
-                return null;
-              }
-              value = value * 16 + hexDigitValue(code);
-            }
-          }
-          code = value;
-        }
-      }
-      // This handles both unescaped characters and the value of unicode
-      // escapes.
-      if (!isUnicodeScalarValue(code)) {
-        stringParseError(
-            "Invalid Unicode scalar value U+${code.toRadixString(16)}",
-            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);
-  }
-}