Example #1
0
        /// <summary>
        /// Parses the attributes of an element tag. When finished, the parser
        /// position is at the next non-space character that follows the attributes.
        /// </summary>
        private HtmlAttributeCollection ParseAttributes(TextParser parser)
        {
            HtmlAttributeCollection attributes = new HtmlAttributeCollection();

            // Parse tag attributes
            parser.MovePastWhitespace();
            char ch = parser.Peek();

            while (HtmlRules.IsAttributeNameCharacter(ch) || HtmlRules.IsQuoteChar(ch))
            {
                // Parse attribute name
                HtmlAttribute attribute = new HtmlAttribute();
                if (HtmlRules.IsQuoteChar(ch))
                {
                    attribute.Name = $"\"{parser.ParseQuotedText()}\"";
                }
                else
                {
                    attribute.Name = parser.ParseWhile(c => HtmlRules.IsAttributeNameCharacter(c));
                }
                Debug.Assert(attribute.Name.Length > 0);

                // Parse attribute value
                parser.MovePastWhitespace();
                if (parser.Peek() == '=')
                {
                    parser.MoveAhead(); // Skip '='
                    parser.MovePastWhitespace();
                    if (HtmlRules.IsQuoteChar(parser.Peek()))
                    {
                        // Quoted attribute value
                        attribute.Value = parser.ParseQuotedText();
                    }
                    else
                    {
                        // Unquoted attribute value
                        attribute.Value = parser.ParseWhile(c => HtmlRules.IsAttributeValueCharacter(c));
                        Debug.Assert(attribute.Value.Length > 0);
                    }
                }
                else
                {
                    // Null attribute value indicates no equals sign
                    attribute.Value = null;
                }
                // Add attribute to tag
                attributes.Add(attribute.Name, attribute);
                // Continue
                parser.MovePastWhitespace();
                ch = parser.Peek();
            }
            return(attributes);
        }
Example #2
0
        /// <summary>
        /// Parses the given selector text and returns the corresponding data structures.
        /// </summary>
        /// <param name="selectorText">The selector text to be parsed.</param>
        /// <remarks>
        /// Returns multiple <see cref="Selector"/>s when the selector contains commas.
        /// </remarks>
        /// <returns>The parsed selector data structures.</returns>
        public static SelectorCollection ParseSelector(string selectorText)
        {
            SelectorCollection selectors = new SelectorCollection();

            if (!string.IsNullOrWhiteSpace(selectorText))
            {
                TextParser parser = new TextParser(selectorText);
                parser.MovePastWhitespace();

                while (!parser.EndOfText)
                {
                    // Test next character
                    char ch = parser.Peek();
                    if (IsNameCharacter(ch) || ch == '*')
                    {
                        // Parse tag name
                        Selector selector = selectors.GetLast(true);
                        if (ch == '*')
                        {
                            selector.Tag = null;    // Match all tags
                        }
                        else
                        {
                            selector.Tag = parser.ParseWhile(c => IsNameCharacter(c));
                        }
                    }
                    else if (SpecialCharacters.TryGetValue(ch, out string name))
                    {
                        // Parse special attributes
                        parser.MoveAhead();
                        string value = parser.ParseWhile(c => IsValueCharacter(c));
                        if (value.Length > 0)
                        {
                            SelectorAttribute attribute = new SelectorAttribute
                            {
                                Name  = name,
                                Value = value,
                                Mode  = SelectorAttributeMode.Contains
                            };

                            Selector selector = selectors.GetLast(true);
                            selector.Attributes.Add(attribute);
                        }
                    }
                    else if (ch == '[')
                    {
                        // Parse attribute selector
                        parser.MoveAhead();
                        parser.MovePastWhitespace();
                        name = parser.ParseWhile(c => IsNameCharacter(c));
                        if (name.Length > 0)
                        {
                            SelectorAttribute attribute = new SelectorAttribute
                            {
                                Name = name
                            };

                            // Parse attribute assignment operator
                            parser.MovePastWhitespace();
                            if (parser.Peek() == '=')
                            {
                                attribute.Mode = SelectorAttributeMode.Match;
                                parser.MoveAhead();
                            }
                            else if (parser.Peek() == ':' && parser.Peek(1) == '=')
                            {
                                attribute.Mode = SelectorAttributeMode.RegEx;
                                parser.MoveAhead(2);
                            }
                            else
                            {
                                attribute.Mode = SelectorAttributeMode.ExistsOnly;
                            }

                            // Parse attribute value
                            if (attribute.Mode != SelectorAttributeMode.ExistsOnly)
                            {
                                parser.MovePastWhitespace();
                                if (HtmlRules.IsQuoteChar(parser.Peek()))
                                {
                                    attribute.Value = parser.ParseQuotedText();
                                }
                                else
                                {
                                    attribute.Value = parser.ParseWhile(c => IsValueCharacter(c));
                                }
                            }

                            Selector selector = selectors.GetLast(true);
                            selector.Attributes.Add(attribute);
                        }

                        // Close out attribute selector
                        parser.MovePastWhitespace();
                        Debug.Assert(parser.Peek() == ']');
                        if (parser.Peek() == ']')
                        {
                            parser.MoveAhead();
                        }
                    }
                    else if (ch == ',')
                    {
                        // Multiple selectors
                        parser.MoveAhead();
                        parser.MovePastWhitespace();
                        selectors.Add(new Selector());
                    }
                    else if (ch == '>')
                    {
                        // Whitespace indicates child selector
                        parser.MoveAhead();
                        parser.MovePastWhitespace();
                        Debug.Assert(selectors.Any());
                        Selector selector = selectors.AddChildSelector();
                        selector.ImmediateChildOnly = true;
                    }
                    else if (char.IsWhiteSpace(ch))
                    {
                        // Handle whitespace
                        parser.MovePastWhitespace();
                        // ',' and '>' change meaning of whitespace
                        if (parser.Peek() != ',' && parser.Peek() != '>')
                        {
                            selectors.AddChildSelector();
                        }
                    }
                    else
                    {
                        // Unknown syntax
                        Debug.Assert(false);
                        parser.MoveAhead();
                    }
                }
            }
            selectors.RemoveEmpty();
            return(selectors);
        }