Move markdown library.

utils/markdown/inline_parser.dart

Index: utils/markdown/inline_parser.dart
diff --git a/utils/markdown/inline_parser.dart b/utils/markdown/inline_parser.dart
deleted file mode 100644
index 80cee9a26e1c31ce25f6f4425ff59b343799b8e4..0000000000000000000000000000000000000000
--- a/utils/markdown/inline_parser.dart
+++ /dev/null
@@ -1,395 +0,0 @@
-// 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.
-
-/// Maintains the internal state needed to parse inline span elements in
-/// markdown.
-class InlineParser {
-  static List<InlineSyntax> get syntaxes() {
-    // Lazy initialize.
-    if (_syntaxes == null) {
-      _syntaxes = <InlineSyntax>[
-        new AutolinkSyntax(),
-        new LinkSyntax(),
-        // "*" surrounded by spaces is left alone.
-        new TextSyntax(@' \* '),
-        // "_" surrounded by spaces is left alone.
-        new TextSyntax(@' _ '),
-        // Leave already-encoded HTML entities alone. Ensures we don't turn
-        // "&amp;" into "&amp;amp;"
-        new TextSyntax(@'&[#a-zA-Z0-9]*;'),
-        // Encode "&".
-        new TextSyntax(@'&', sub: '&amp;'),
-        // Encode "<". (Why not encode ">" too? Gruber is toying with us.)
-        new TextSyntax(@'<', sub: '&lt;'),
-        // Parse "**strong**" tags.
-        new TagSyntax(@'\*\*', tag: 'strong'),
-        // Parse "__strong__" tags.
-        new TagSyntax(@'__', tag: 'strong'),
-        // Parse "*emphasis*" tags.
-        new TagSyntax(@'\*', tag: 'em'),
-        // Parse "_emphasis_" tags.
-        // TODO(rnystrom): Underscores in the middle of a word should not be
-        // parsed as emphasis like_in_this.
-        new TagSyntax(@'_', tag: 'em'),
-        // Parse inline code within double backticks: "``code``".
-        new CodeSyntax(@'``\s?((?:.|\n)*?)\s?``'),
-        // Parse inline code within backticks: "`code`".
-        new CodeSyntax(@'`([^`]*)`')
-      ];
-    }
-
-    return _syntaxes;
-  }
-
-  static List<InlineSyntax> _syntaxes;
-
-  /// The string of markdown being parsed.
-  final String source;
-
-  /// The markdown document this parser is parsing.
-  final Document document;
-
-  /// The current read position.
-  int pos = 0;
-
-  /// Starting position of the last unconsumed text.
-  int start = 0;
-
-  final List<TagState> _stack;
-
-  InlineParser(this.source, this.document)
-    : _stack = <TagState>[];
-
-  List<Node> parse() {
-    // Make a fake top tag to hold the results.
-    _stack.add(new TagState(0, 0, null));
-
-    while (!isDone) {
-      bool matched = false;
-
-      // See if any of the current tags on the stack match. We don't allow tags
-      // of the same kind to nest, so this takes priority over other possible // matches.
-      for (int i = _stack.length - 1; i > 0; i--) {
-        if (_stack[i].tryMatch(this)) {
-          matched = true;
-          break;
-        }
-      }
-      if (matched) continue;
-
-      // See if the current text matches any defined markdown syntax.
-      for (final syntax in syntaxes) {
-        if (syntax.tryMatch(this)) {
-          matched = true;
-          break;
-        }
-      }
-      if (matched) continue;
-
-      // If we got here, it's just text.
-      advanceBy(1);
-    }
-
-    // Unwind any unmatched tags and get the results.
-    return _stack[0].close(this, null);
-  }
-
-  writeText() {
-    writeTextRange(start, pos);
-    start = pos;
-  }
-
-  writeTextRange(int start, int end) {
-    if (end > start) {
-      final text = source.substring(start, end);
-      final nodes = _stack.last().children;
-
-      // If the previous node is text too, just append.
-      if ((nodes.length > 0) && (nodes.last() is Text)) {
-        final newNode = new Text('${nodes.last().text}$text');
-        nodes[nodes.length - 1] = newNode;
-      } else {
-        nodes.add(new Text(text));
-      }
-    }
-  }
-
-  addNode(Node node) {
-    _stack.last().children.add(node);
-  }
-
-  // TODO(rnystrom): Only need this because RegExp doesn't let you start
-  // searching from a given offset.
-  String get currentSource() => source.substring(pos, source.length);
-
-  bool get isDone() => pos == source.length;
-
-  void advanceBy(int length) {
-    pos += length;
-  }
-
-  void consume(int length) {
-    pos += length;
-    start = pos;
-  }
-}
-
-/// Represents one kind of markdown tag that can be parsed.
-class InlineSyntax {
-  final RegExp pattern;
-
-  InlineSyntax(String pattern)
-    : pattern = new RegExp(pattern, true);
-  // TODO(rnystrom): Should use named arg for RegExp multiLine.
-
-  bool tryMatch(InlineParser parser) {
-    final startMatch = pattern.firstMatch(parser.currentSource);
-    if ((startMatch != null) && (startMatch.start() == 0)) {
-      // Write any existing plain text up to this point.
-      parser.writeText();
-
-      if (onMatch(parser, startMatch)) {
-        parser.consume(startMatch[0].length);
-      }
-      return true;
-    }
-    return false;
-  }
-
-  abstract bool onMatch(InlineParser parser, Match match);
-}
-
-/// Matches stuff that should just be passed through as straight text.
-class TextSyntax extends InlineSyntax {
-  String substitute;
-  TextSyntax(String pattern, [String sub])
-    : super(pattern),
-      substitute = sub;
-
-  bool onMatch(InlineParser parser, Match match) {
-    if (substitute == null) {
-      // Just use the original matched text.
-      parser.advanceBy(match[0].length);
-      return false;
-    }
-
-    // Insert the substitution.
-    parser.addNode(new Text(substitute));
-    return true;
-  }
-}
-
-/// Matches autolinks like `<http://foo.com>`.
-class AutolinkSyntax extends InlineSyntax {
-  AutolinkSyntax()
-    : super(@'<((http|https|ftp)://[^>]*)>');
-  // TODO(rnystrom): Make case insensitive.
-
-  bool onMatch(InlineParser parser, Match match) {
-    final url = match[1];
-
-    final anchor = new Element.text('a', escapeHtml(url));
-    anchor.attributes['href'] = url;
-    parser.addNode(anchor);
-
-    return true;
-  }
-}
-
-/// Matches syntax that has a pair of tags and becomes an element, like `*` for
-/// `<em>`. Allows nested tags.
-class TagSyntax extends InlineSyntax {
-  final RegExp endPattern;
-  final String tag;
-
-  TagSyntax(String pattern, [String tag, String end = null])
-    : super(pattern),
-      endPattern = new RegExp((end != null) ? end : pattern, true),
-      tag = tag;
-    // TODO(rnystrom): Doing this.field doesn't seem to work with named args.
-    // TODO(rnystrom): Should use named arg for RegExp multiLine.
-
-  bool onMatch(InlineParser parser, Match match) {
-    parser._stack.add(new TagState(parser.pos,
-      parser.pos + match[0].length, this));
-    return true;
-  }
-
-  bool onMatchEnd(InlineParser parser, Match match, TagState state) {
-    parser.addNode(new Element(tag, state.children));
-    return true;
-  }
-}
-
-/// Matches inline links like `[blah] [id]` and `[blah] (url)`.
-class LinkSyntax extends TagSyntax {
-  /// The regex for the end of a link needs to handle both reference style and
-  /// inline styles as well as optional titles for inline links. To make that
-  /// a bit more palatable, this breaks it into pieces.
-  static get linkPattern() {
-    final refLink    = @'\s?\[([^\]]*)\]';        // "[id]" reflink id.
-    final title      = @'(?:[ ]*"([^"]+)"|)';     // Optional title in quotes.
-    final inlineLink = '\\s?\\(([^ )]+)$title\\)'; // "(url "title")" link.
-    return '\](?:($refLink|$inlineLink)|)';
-
-    // The groups matched by this are:
-    // 1: Will be non-empty if it's either a ref or inline link. Will be empty
-    //    if it's just a bare pair of square brackets with nothing after them.
-    // 2: Contains the id inside [] for a reference-style link.
-    // 3: Contains the URL for an inline link.
-    // 4: Contains the title, if present, for an inline link.
-  }
-
-  LinkSyntax()
-    : super(@'\[', end: linkPattern);
-
-  bool onMatchEnd(InlineParser parser, Match match, TagState state) {
-    var url;
-    var title;
-
-    // If we didn't match refLink or inlineLink, then it means there was
-    // nothing after the first square bracket, so it isn't a normal markdown
-    // link at all. Instead, we allow users of the library to specify a special
-    // resolver function ([setImplicitLinkResolver]) that may choose to handle
-    // this. Otherwise, it's just treated as plain text.
-    if ((match[1] == null) || (match[1] == '')) {
-      if (_implicitLinkResolver == null) return false;
-
-      // Only allow implicit links if the content is just text.
-      // TODO(rnystrom): Do we want to relax this?
-      if (state.children.length != 1) return false;
-      if (state.children[0] is! Text) return false;
-
-      Text link = state.children[0];
-
-      // See if we have a resolver that will generate a link for us.
-      final node = _implicitLinkResolver(link.text);
-      if (node == null) return false;
-
-      parser.addNode(node);
-      return true;
-    }
-
-    if ((match[3] != null) && (match[3] != '')) {
-      // Inline link like [foo](url).
-      url = match[3];
-      title = match[4];
-
-      // For whatever reason, markdown allows angle-bracketed URLs here.
-      if (url.startsWith('<') && url.endsWith('>')) {
-        url = url.substring(1, url.length - 1);
-      }
-    } else {
-      // Reference link like [foo] [bar].
-      var id = match[2];
-      if (id == '') {
-        // The id is empty ("[]") so infer it from the contents.
-        id = parser.source.substring(state.startPos + 1, parser.pos);
-      }
-
-      // Look up the link.
-      final link = parser.document.refLinks[id];
-      // If it's an unknown link just emit plaintext.
-      if (link == null) return false;
-
-      url = link.url;
-      title = link.title;
-    }
-
-    final anchor = new Element('a', state.children);
-    anchor.attributes['href'] = escapeHtml(url);
-    if ((title != null) && (title != '')) {
-      anchor.attributes['title'] = escapeHtml(title);
-    }
-
-    parser.addNode(anchor);
-    return true;
-  }
-}
-
-/// Matches backtick-enclosed inline code blocks.
-class CodeSyntax extends InlineSyntax {
-  CodeSyntax(String pattern)
-    : super(pattern);
-
-  bool onMatch(InlineParser parser, Match match) {
-    parser.addNode(new Element.text('code', escapeHtml(match[1])));
-    return true;
-  }
-}
-
-/// Keeps track of a currently open tag while it is being parsed. The parser
-/// maintains a stack of these so it can handle nested tags.
-class TagState {
-  /// The point in the original source where this tag started.
-  int startPos;
-
-  /// The point in the original source where open tag ended.
-  int endPos;
-
-  /// The syntax that created this node.
-  final TagSyntax syntax;
-
-  /// The children of this node. Will be `null` for text nodes.
-  final List<Node> children;
-
-  TagState(this.startPos, this.endPos, this.syntax)
-    : children = <Node>[];
-
-  /// Attempts to close this tag by matching the current text against its end
-  /// pattern.
-  bool tryMatch(InlineParser parser) {
-    Match endMatch = syntax.endPattern.firstMatch(parser.currentSource);
-    if ((endMatch != null) && (endMatch.start() == 0)) {
-      // Close the tag.
-      close(parser, endMatch);
-      return true;
-    }
-
-    return false;
-  }
-
-  /// Pops this tag off the stack, completes it, and adds it to the output.
-  /// Will discard any unmatched tags that happen to be above it on the stack.
-  /// If this is the last node in the stack, returns its children.
-  List<Node> close(InlineParser parser, Match endMatch) {
-    // If there are unclosed tags on top of this one when it's closed, that
-    // means they are mismatched. Mismatched tags are treated as plain text in
-    // markdown. So for each tag above this one, we write its start tag as text
-    // and then adds its children to this one's children.
-    int index = parser._stack.indexOf(this);
-
-    // Remove the unmatched children.
-    final unmatchedTags = parser._stack.getRange(index + 1,
-        parser._stack.length - index - 1);
-    parser._stack.removeRange(index + 1, parser._stack.length - index - 1);
-
-    // Flatten them out onto this tag.
-    for (final unmatched in unmatchedTags) {
-      // Write the start tag as text.
-      parser.writeTextRange(unmatched.startPos, unmatched.endPos);
-
-      // Bequeath its children unto this tag.
-      children.addAll(unmatched.children);
-    }
-
-    // Pop this off the stack.
-    parser.writeText();
-    parser._stack.removeLast();
-
-    // If the stack is empty now, this is the special "results" node.
-    if (parser._stack.length == 0) return children;
-
-    // We are still parsing, so add this to its parent's children.
-    if (syntax.onMatchEnd(parser, endMatch, this)) {
-      parser.consume(endMatch[0].length);
-    } else {
-      // Didn't close correctly so revert to text.
-      parser.start = startPos;
-      parser.advanceBy(endMatch[0].length);
-    }
-
-    return null;
-  }
-}