Template parser

utils/template/tokenizer.dart

+// Copyright (c) 2011, 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.
+
+class Tokenizer extends TokenizerBase {
+  TokenKind tmplTokens;
+
+  bool _selectorParsing;
+
+  Tokenizer(SourceFile source, bool skipWhitespace, [int index = 0])
+    : super(source, skipWhitespace, index), _selectorParsing = false {
+      tmplTokens = new TokenKind();
+  }
+
+  int get startIndex() => _startIndex;
+  void set index(int idx) {
+    _index = idx;
+  }
+
+  Token next([bool inTag = true]) {
+    // keep track of our starting position
+    _startIndex = _index;
+
+    if (_interpStack != null && _interpStack.depth == 0) {
+      var istack = _interpStack;
+      _interpStack = _interpStack.pop();
+
+      /* TODO(terry): Enable for variable and string interpolation.
+       * if (istack.isMultiline) {
+       *   return finishMultilineStringBody(istack.quote);
+       * } else {
+       *   return finishStringBody(istack.quote);
+       * }
+       */
+    }
+
+    int ch;
+    ch = _nextChar();
+    switch(ch) {
+      case 0:
+        return _finishToken(TokenKind.END_OF_FILE);
+      case tmplTokens.tokens[TokenKind.SPACE]:
+      case tmplTokens.tokens[TokenKind.TAB]:
+      case tmplTokens.tokens[TokenKind.NEWLINE]:
+      case tmplTokens.tokens[TokenKind.RETURN]:
+        return finishWhitespace();
+      case tmplTokens.tokens[TokenKind.END_OF_FILE]:
+        return _finishToken(TokenKind.END_OF_FILE);
+      case tmplTokens.tokens[TokenKind.LPAREN]:
+        return _finishToken(TokenKind.LPAREN);
+      case tmplTokens.tokens[TokenKind.RPAREN]:
+        return _finishToken(TokenKind.RPAREN);
+      case tmplTokens.tokens[TokenKind.COMMA]:
+        return _finishToken(TokenKind.COMMA);
+      case tmplTokens.tokens[TokenKind.LBRACE]:
+        return _finishToken(TokenKind.LBRACE);
+      case tmplTokens.tokens[TokenKind.RBRACE]:
+        return _finishToken(TokenKind.RBRACE);
+      case tmplTokens.tokens[TokenKind.LESS_THAN]:
+        return _finishToken(TokenKind.LESS_THAN);
+      case tmplTokens.tokens[TokenKind.GREATER_THAN]:
+        return _finishToken(TokenKind.GREATER_THAN);
+      case tmplTokens.tokens[TokenKind.EQUAL]:
+        if (inTag) {
+          if (_maybeEatChar(tmplTokens.tokens[TokenKind.SINGLE_QUOTE])) {
+            return finishQuotedAttrValue(
+              tmplTokens.tokens[TokenKind.SINGLE_QUOTE]);
+          } else if (_maybeEatChar(tmplTokens.tokens[TokenKind.DOUBLE_QUOTE])) {
+            return finishQuotedAttrValue(
+              tmplTokens.tokens[TokenKind.DOUBLE_QUOTE]);
+          } else if (isAttributeValueStart(_peekChar())) {
+            return finishAttrValue();
+          }
+        }
+        return _finishToken(TokenKind.EQUAL);
+      case tmplTokens.tokens[TokenKind.SLASH]:
+        if (_maybeEatChar(tmplTokens.tokens[TokenKind.GREATER_THAN])) {
+          return _finishToken(TokenKind.END_NO_SCOPE_TAG);          // />
+        } else {
+          return _finishToken(TokenKind.SLASH);
+        }
+      case tmplTokens.tokens[TokenKind.DOLLAR]:
+        if (_maybeEatChar(tmplTokens.tokens[TokenKind.LBRACE])) {
+          if (_maybeEatChar(tmplTokens.tokens[TokenKind.HASH])) {
+            return _finishToken(TokenKind.START_COMMAND);           // ${#
+          } else if (_maybeEatChar(tmplTokens.tokens[TokenKind.SLASH])) {
+            return _finishToken(TokenKind.END_COMMAND);             // ${/
+          } else {
+            return _finishToken(TokenKind.START_EXPRESSION);        // ${
+          }
+        } else {
+          return _finishToken(TokenKind.DOLLAR);
+        }
+
+      default:
+        if (TokenizerHelpers.isIdentifierStart(ch)) {
+          return this.finishIdentifier();
+        } else if (isDigit(ch)) {
+          return this.finishNumber();
+        } else {
+          return _errorToken();
+        }
+    }
+  }
+
+  // TODO(jmesserly): we need a way to emit human readable error messages from
+  // the tokenizer.
+  Token _errorToken([String message = null]) {
+    return _finishToken(TokenKind.ERROR);
+  }
+
+  int getIdentifierKind() {
+    // Is the identifier an element?
+    int tokId = TokenKind.matchElements(_text, _startIndex,
+      _index - _startIndex);
+    if (tokId == -1) {
+      // No, is it an attribute?
+//      tokId = TokenKind.matchAttributes(_text, _startIndex, _index - _startIndex);
+    }
+    if (tokId == -1) {
+      tokId = TokenKind.matchKeywords(_text, _startIndex, _index - _startIndex);
+    }
+
+    return tokId >= 0 ? tokId : TokenKind.IDENTIFIER;
+  }
+
+  // Need to override so CSS version of isIdentifierPart is used.
+  Token finishIdentifier() {
+    while (_index < _text.length) {
+//      if (!TokenizerHelpers.isIdentifierPart(_text.charCodeAt(_index++))) {
+      if (!TokenizerHelpers.isIdentifierPart(_text.charCodeAt(_index))) {
+//        _index--;
+        break;
+      } else {
+        _index += 1;
+      }
+    }
+    if (_interpStack != null && _interpStack.depth == -1) {
+      _interpStack.depth = 0;
+    }
+    int kind = getIdentifierKind();
+    if (kind == TokenKind.IDENTIFIER) {
+      return _finishToken(TokenKind.IDENTIFIER);
+    } else {
+      return _finishToken(kind);
+    }
+  }
+
+  Token _makeAttributeValueToken(List<int> buf) {
+    final s = new String.fromCharCodes(buf);
+    return new LiteralToken(TokenKind.ATTR_VALUE, _source, _startIndex, _index,
+      s);
+  }
+
+  /* quote if -1 signals to read upto first whitespace otherwise read upto
+   * single or double quote char.
+   */
+  Token finishQuotedAttrValue([int quote = -1]) {
+    var buf = new List<int>();
+    while (true) {
+      int ch = _nextChar();
+      if (ch == quote) {
+        return _makeAttributeValueToken(buf);
+      } else if (ch == 0) {
+        return _errorToken();
+      } else {
+        buf.add(ch);
+      }
+    }
+  }
+
+  Token finishAttrValue() {
+    var buf = new List<int>();
+    while (true) {
+      int ch = _peekChar();
+      if (isWhitespace(ch) || isSlash(ch) || isCloseTag(ch)) {
+        return _makeAttributeValueToken(buf);
+      } else if (ch == 0) {
+        return _errorToken();
+      } else {
+        buf.add(_nextChar());
+      }
+    }
+  }
+
+  Token finishNumber() {
+    eatDigits();
+
+    if (_peekChar() == 46/*.*/) {
+      // Handle the case of 1.toString().
+      _nextChar();
+      if (isDigit(_peekChar())) {
+        eatDigits();
+        return _finishToken(TokenKind.DOUBLE);
+      } else {
+        _index -= 1;
+      }
+    }
+
+    return _finishToken(TokenKind.INTEGER);
+  }
+
+  bool maybeEatDigit() {
+    if (_index < _text.length && isDigit(_text.charCodeAt(_index))) {
+      _index += 1;
+      return true;
+    }
+    return false;
+  }
+
+  void eatHexDigits() {
+    while (_index < _text.length) {
+     if (isHexDigit(_text.charCodeAt(_index))) {
+       _index += 1;
+     } else {
+       return;
+     }
+    }
+  }
+
+  bool maybeEatHexDigit() {
+    if (_index < _text.length && isHexDigit(_text.charCodeAt(_index))) {
+      _index += 1;
+      return true;
+    }
+    return false;
+  }
+
+  Token finishMultiLineComment() {
+    while (true) {
+      int ch = _nextChar();
+      if (ch == 0) {
+        return _finishToken(TokenKind.INCOMPLETE_COMMENT);
+      } else if (ch == 42/*'*'*/) {
+        if (_maybeEatChar(47/*'/'*/)) {
+          if (_skipWhitespace) {
+            return next();
+          } else {
+            return _finishToken(TokenKind.COMMENT);
+          }
+        }
+      } else if (ch == tmplTokens.tokens[TokenKind.MINUS]) {
+        /* Check if close part of Comment Definition --> (CDC). */
+        if (_maybeEatChar(tmplTokens.tokens[TokenKind.MINUS])) {
+          if (_maybeEatChar(tmplTokens.tokens[TokenKind.GREATER_THAN])) {
+            if (_skipWhitespace) {
+              return next();
+            } else {
+              return _finishToken(TokenKind.HTML_COMMENT);
+            }
+          }
+        }
+      }
+    }
+    return _errorToken();
+  }
+
+}
+
+
+/** Static helper methods. */
+class TokenizerHelpers {
+  static bool isIdentifierStart(int c) {
+    return ((c >= 97/*a*/ && c <= 122/*z*/) ||
+        (c >= 65/*A*/ && c <= 90/*Z*/) || c == 95/*_*/);
+  }
+
+  static bool isDigit(int c) {
+    return (c >= 48/*0*/ && c <= 57/*9*/);
+  }
+
+  static bool isHexDigit(int c) {
+    return (isDigit(c) || (c >= 97/*a*/ && c <= 102/*f*/) ||
+        (c >= 65/*A*/ && c <= 70/*F*/));
+  }
+
+  static bool isWhitespace(int c) {
+    return (c == 32/*' '*/ || c == 9/*'\t'*/ || c == 10/*'\n'*/ ||
+        c == 13/*'\r'*/);
+  }
+
+  static bool isIdentifierPart(int c) {
+    return (isIdentifierStart(c) || isDigit(c) || c == 45/*-*/ ||
+        c == 58/*:*/ || c == 46/*.*/);
+  }
+
+  static bool isInterpIdentifierPart(int c) {
+    return (isIdentifierStart(c) || isDigit(c));
+  }
+
+  static bool isAttributeValueStart(int c) {
+    return !isWhitespace(c) && !isSlash(c) && !isCloseTag(c);
+  }
+
+  static bool isSlash(int c) {
+    return (c == 47/* / */);
+  }
+
+  static bool isCloseTag(int c) {
+    return (c == 62/* > */);
+  }
+}