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1656 lines
66 KiB
1656 lines
66 KiB
using System;
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using System.Collections.Generic;
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using System.Configuration;
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using System.Text;
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using System.Text.RegularExpressions;
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namespace MarkdownSharp
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{
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/// <summary>
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/// Markdown is a text-to-HTML conversion tool for web writers.
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/// Markdown allows you to write using an easy-to-read, easy-to-write plain text format,
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/// then convert it to structurally valid XHTML (or HTML).
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/// </summary>
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internal class Markdown
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{
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private const string _version = "1.13";
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#region Constructors and Options
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/// <summary>
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/// Create a new Markdown instance using default options
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/// </summary>
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public Markdown()
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{
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}
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#if NETFX || NETCORE
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/// <summary>
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/// Create a new Markdown instance and optionally load options from a configuration
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/// file. There they should be stored in the appSettings section, available options are:
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/// Markdown.StrictBoldItalic (true/false)
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/// Markdown.EmptyElementSuffix (">" or " />" without the quotes)
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/// Markdown.LinkEmails (true/false)
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/// Markdown.AutoNewLines (true/false)
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/// Markdown.AutoHyperlink (true/false)
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/// Markdown.AsteriskIntraWordEmphasis (true/false)
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/// </summary>
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public Markdown(bool loadOptionsFromConfigFile)
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{
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if (!loadOptionsFromConfigFile) return;
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var settings = ConfigurationManager.AppSettings;
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foreach (string key in settings.Keys)
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{
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switch (key)
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{
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case "Markdown.AutoHyperlink":
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AutoHyperlink = Convert.ToBoolean(settings[key]);
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break;
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case "Markdown.AutoNewlines":
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AutoNewLines = Convert.ToBoolean(settings[key]);
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break;
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case "Markdown.EmptyElementSuffix":
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EmptyElementSuffix = settings[key];
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break;
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case "Markdown.LinkEmails":
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LinkEmails = Convert.ToBoolean(settings[key]);
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break;
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case "Markdown.StrictBoldItalic":
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StrictBoldItalic = Convert.ToBoolean(settings[key]);
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break;
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case "Markdown.AsteriskIntraWordEmphasis":
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AsteriskIntraWordEmphasis = Convert.ToBoolean(settings[key]);
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break;
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}
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}
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}
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#endif
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/// <summary>
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/// Create a new Markdown instance and set the options from the MarkdownOptions object.
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/// </summary>
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public Markdown(MarkdownOptions options)
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{
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AutoHyperlink = options.AutoHyperlink;
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AutoNewLines = options.AutoNewlines;
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if (!string.IsNullOrEmpty(options.EmptyElementSuffix))
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EmptyElementSuffix = options.EmptyElementSuffix;
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LinkEmails = options.LinkEmails;
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StrictBoldItalic = options.StrictBoldItalic;
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AsteriskIntraWordEmphasis = options.AsteriskIntraWordEmphasis;
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}
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/// <summary>
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/// use ">" for HTML output, or " />" for XHTML output
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/// </summary>
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public string EmptyElementSuffix { get; set; } = " />";
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/// <summary>
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/// when false, email addresses will never be auto-linked
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/// WARNING: this is a significant deviation from the markdown spec
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/// </summary>
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public bool LinkEmails { get; set; } = true;
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/// <summary>
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/// when true, bold and italic require non-word characters on either side
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/// WARNING: this is a significant deviation from the markdown spec
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/// </summary>
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public bool StrictBoldItalic { get; set; } = false;
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/// <summary>
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/// when true, asterisks may be used for intraword emphasis
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/// this does nothing if StrictBoldItalic is false
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/// </summary>
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public bool AsteriskIntraWordEmphasis { get; set; } = false;
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/// <summary>
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/// when true, RETURN becomes a literal newline
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/// WARNING: this is a significant deviation from the markdown spec
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/// </summary>
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public bool AutoNewLines { get; set; } = false;
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/// <summary>
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/// when true, (most) bare plain URLs are auto-hyperlinked
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/// WARNING: this is a significant deviation from the markdown spec
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/// </summary>
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public bool AutoHyperlink { get; set; } = false;
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#endregion
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/// <summary>
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/// maximum nested depth of [] and () supported by the transform; implementation detail
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/// </summary>
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private const int _nestDepth = 6;
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/// <summary>
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/// Tabs are automatically converted to spaces as part of the transform
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/// this constant determines how "wide" those tabs become in spaces
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/// </summary>
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private const int _tabWidth = 4;
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private const string _markerUL = "[*+-]";
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private const string _markerOL = @"\d+[.]";
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private static readonly Dictionary<string, string> _escapeTable;
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private static readonly Dictionary<string, string> _invertedEscapeTable;
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private static readonly Dictionary<string, string> _backslashEscapeTable;
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private readonly Dictionary<string, string> _urls = new Dictionary<string, string>();
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private readonly Dictionary<string, string> _titles = new Dictionary<string, string>();
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private readonly Dictionary<string, string> _htmlBlocks = new Dictionary<string, string>();
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private int _listLevel;
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private const string AutoLinkPreventionMarker = "\x1AP"; // temporarily replaces "://" where auto-linking shouldn't happen
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/// <summary>
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/// In the static constuctor we'll initialize what stays the same across all transforms.
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/// </summary>
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static Markdown()
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{
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// Table of hash values for escaped characters:
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_escapeTable = new Dictionary<string, string>();
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_invertedEscapeTable = new Dictionary<string, string>();
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// Table of hash value for backslash escaped characters:
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_backslashEscapeTable = new Dictionary<string, string>();
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string backslashPattern = "";
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foreach (char c in @"\`*_{}[]()>#+-.!/:")
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{
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string key = c.ToString();
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string hash = GetHashKey(key, isHtmlBlock: false);
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_escapeTable.Add(key, hash);
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_invertedEscapeTable.Add(hash, key);
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_backslashEscapeTable.Add(@"\" + key, hash);
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backslashPattern += Regex.Escape(@"\" + key) + "|";
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}
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_backslashEscapes = new Regex(backslashPattern.Substring(0, backslashPattern.Length - 1), RegexOptions.Compiled);
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}
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/// <summary>
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/// current version of MarkdownSharp;
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/// see http://code.google.com/p/markdownsharp/ for the latest code or to contribute
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/// </summary>
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public string Version
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{
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get { return _version; }
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}
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/// <summary>
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/// Transforms the provided Markdown-formatted text to HTML;
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/// see http://en.wikipedia.org/wiki/Markdown
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/// </summary>
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/// <remarks>
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/// The order in which other subs are called here is
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/// essential. Link and image substitutions need to happen before
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/// EscapeSpecialChars(), so that any *'s or _'s in the a
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/// and img tags get encoded.
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/// </remarks>
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public string Transform(string text)
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{
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if (string.IsNullOrEmpty(text)) return "";
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Setup();
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text = Normalize(text);
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text = HashHTMLBlocks(text);
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text = StripLinkDefinitions(text);
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text = RunBlockGamut(text);
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text = Unescape(text);
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Cleanup();
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return text + "\n";
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}
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/// <summary>
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/// Perform transformations that form block-level tags like paragraphs, headers, and list items.
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/// </summary>
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private string RunBlockGamut(string text, bool unhash = true, bool createParagraphs = true)
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{
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text = DoHeaders(text);
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text = DoHorizontalRules(text);
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text = DoLists(text);
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text = DoCodeBlocks(text);
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text = DoBlockQuotes(text);
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// We already ran HashHTMLBlocks() before, in Markdown(), but that
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// was to escape raw HTML in the original Markdown source. This time,
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// we're escaping the markup we've just created, so that we don't wrap
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// <p> tags around block-level tags.
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text = HashHTMLBlocks(text);
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return FormParagraphs(text, unhash: unhash, createParagraphs: createParagraphs);
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}
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/// <summary>
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/// Perform transformations that occur *within* block-level tags like paragraphs, headers, and list items.
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/// </summary>
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private string RunSpanGamut(string text)
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{
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text = DoCodeSpans(text);
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text = EscapeSpecialCharsWithinTagAttributes(text);
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text = EscapeBackslashes(text);
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// Images must come first, because ![foo][f] looks like an anchor.
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text = DoImages(text);
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text = DoAnchors(text);
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// Must come after DoAnchors(), because you can use < and >
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// delimiters in inline links like [this](<url>).
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text = DoAutoLinks(text);
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text = text.Replace(AutoLinkPreventionMarker, "://");
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text = EncodeAmpsAndAngles(text);
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text = DoItalicsAndBold(text);
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return DoHardBreaks(text);
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}
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private static readonly Regex _newlinesLeadingTrailing = new Regex(@"^\n+|\n+\z", RegexOptions.Compiled);
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private static readonly Regex _newlinesMultiple = new Regex(@"\n{2,}", RegexOptions.Compiled);
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private static readonly Regex _leadingWhitespace = new Regex("^[ ]*", RegexOptions.Compiled);
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private static readonly Regex _htmlBlockHash = new Regex("\x1AH\\d+H", RegexOptions.Compiled);
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/// <summary>
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/// splits on two or more newlines, to form "paragraphs";
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/// each paragraph is then unhashed (if it is a hash and unhashing isn't turned off) or wrapped in HTML p tag
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/// </summary>
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private string FormParagraphs(string text, bool unhash = true, bool createParagraphs = true)
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{
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// split on two or more newlines
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string[] grafs = _newlinesMultiple.Split(_newlinesLeadingTrailing.Replace(text, ""));
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for (int i = 0; i < grafs.Length; i++)
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{
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if (grafs[i].Contains("\x1AH"))
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{
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// unhashify HTML blocks
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if (unhash)
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{
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int sanityCheck = 50; // just for safety, guard against an infinite loop
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bool keepGoing = true; // as long as replacements where made, keep going
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while (keepGoing && sanityCheck > 0)
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{
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keepGoing = false;
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grafs[i] = _htmlBlockHash.Replace(grafs[i], match =>
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{
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keepGoing = true;
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return _htmlBlocks[match.Value];
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});
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sanityCheck--;
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}
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/* if (keepGoing)
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{
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// Logging of an infinite loop goes here.
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// If such a thing should happen, please open a new issue on http://code.google.com/p/markdownsharp/
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// with the input that caused it.
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}*/
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}
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}
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else
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{
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// do span level processing inside the block, then wrap result in <p> tags
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grafs[i] = _leadingWhitespace.Replace(RunSpanGamut(grafs[i]), createParagraphs ? "<p>" : "") + (createParagraphs ? "</p>" : "");
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}
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}
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return string.Join("\n\n", grafs);
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}
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private void Setup()
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{
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// Clear the global hashes. If we don't clear these, you get conflicts
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// from other articles when generating a page which contains more than
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// one article (e.g. an index page that shows the N most recent
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// articles):
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_urls.Clear();
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_titles.Clear();
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_htmlBlocks.Clear();
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_listLevel = 0;
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}
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private void Cleanup()
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{
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Setup();
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}
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private static string _nestedBracketsPattern;
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/// <summary>
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/// Reusable pattern to match balanced [brackets]. See Friedl's
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/// "Mastering Regular Expressions", 2nd Ed., pp. 328-331.
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/// </summary>
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private static string GetNestedBracketsPattern()
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{
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// in other words [this] and [this[also]] and [this[also[too]]]
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// up to _nestDepth
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if (_nestedBracketsPattern == null)
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{
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_nestedBracketsPattern =
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RepeatString(@"
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(?> # Atomic matching
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[^\[\]]+ # Anything other than brackets
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\[
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", _nestDepth) + RepeatString(
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@" \]
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)*"
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, _nestDepth);
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}
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return _nestedBracketsPattern;
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}
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private static string _nestedParensPattern;
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/// <summary>
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/// Reusable pattern to match balanced (parens). See Friedl's
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/// "Mastering Regular Expressions", 2nd Ed., pp. 328-331.
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/// </summary>
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private static string GetNestedParensPattern()
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{
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// in other words (this) and (this(also)) and (this(also(too)))
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// up to _nestDepth
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if (_nestedParensPattern == null)
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{
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_nestedParensPattern =
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RepeatString(@"
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(?> # Atomic matching
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[^()\s]+ # Anything other than parens or whitespace
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\(
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", _nestDepth) + RepeatString(
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@" \)
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)*"
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, _nestDepth);
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}
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return _nestedParensPattern;
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}
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private static readonly Regex _linkDef = new Regex(string.Format(@"
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^[ ]{{0,{0}}}\[([^\[\]]+)\]: # id = $1
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[ ]*
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\n? # maybe *one* newline
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[ ]*
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<?(\S+?)>? # url = $2
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[ ]*
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\n? # maybe one newline
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[ ]*
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(?:
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(?<=\s) # lookbehind for whitespace
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[""(]
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(.+?) # title = $3
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["")]
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[ ]*
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)? # title is optional
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(?:\n+|\Z)", _tabWidth - 1), RegexOptions.Multiline | RegexOptions.IgnorePatternWhitespace | RegexOptions.Compiled);
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/// <summary>
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/// Strips link definitions from text, stores the URLs and titles in hash references.
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/// </summary>
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/// <remarks>
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/// ^[id]: url "optional title"
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/// </remarks>
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private string StripLinkDefinitions(string text) => _linkDef.Replace(text, new MatchEvaluator(LinkEvaluator));
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private string LinkEvaluator(Match match)
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{
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string linkID = match.Groups[1].Value.ToLowerInvariant();
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_urls[linkID] = EncodeAmpsAndAngles(match.Groups[2].Value);
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if (match.Groups[3]?.Length > 0)
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_titles[linkID] = match.Groups[3].Value.Replace("\"", """);
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return "";
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}
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// compiling this monster regex results in worse performance. trust me.
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private static readonly Regex _blocksHtml = new Regex(GetBlockPattern(), RegexOptions.Multiline | RegexOptions.IgnorePatternWhitespace);
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/// <summary>
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/// derived pretty much verbatim from PHP Markdown
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/// </summary>
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private static string GetBlockPattern()
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{
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// Hashify HTML blocks:
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// We only want to do this for block-level HTML tags, such as headers,
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// lists, and tables. That's because we still want to wrap <p>s around
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// "paragraphs" that are wrapped in non-block-level tags, such as anchors,
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// phrase emphasis, and spans. The list of tags we're looking for is
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// hard-coded:
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//
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// * List "a" is made of tags which can be both inline or block-level.
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// These will be treated block-level when the start tag is alone on
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// its line, otherwise they're not matched here and will be taken as
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// inline later.
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// * List "b" is made of tags which are always block-level;
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//
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const string blockTagsA = "ins|del";
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const string blockTagsB = "p|div|h[1-6]|blockquote|pre|table|dl|ol|ul|address|script|noscript|form|fieldset|iframe|math";
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// Regular expression for the content of a block tag.
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const string attr = @"
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(?> # optional tag attributes
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\s # starts with whitespace
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(?>
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[^>""/]+ # text outside quotes
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/+(?!>) # slash not followed by >
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""[^""]*"" # text inside double quotes (tolerate >)
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'[^']*' # text inside single quotes (tolerate >)
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)*
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)?
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";
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string content = RepeatString(@"
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(?>
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[^<]+ # content without tag
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<\2 # nested opening tag
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" + attr + @" # attributes
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(?>
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/>
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>", _nestDepth) + // end of opening tag
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".*?" + // last level nested tag content
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RepeatString(@"
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</\2\s*> # closing nested tag
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)
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<(?!/\2\s*> # other tags with a different name
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)
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)*", _nestDepth);
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string content2 = content.Replace(@"\2", @"\3");
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// First, look for nested blocks, e.g.:
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// <div>
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// <div>
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// tags for inner block must be indented.
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// </div>
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// </div>
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//
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// The outermost tags must start at the left margin for this to match, and
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// the inner nested divs must be indented.
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// We need to do this before the next, more liberal match, because the next
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// match will start at the first `<div>` and stop at the first `</div>`.
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string pattern = @"
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(?>
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(?>
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(?<=\n) # Starting at the beginning of a line
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| # or
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\A\n? # the beginning of the doc
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)
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( # save in $1
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# Match from `\n<tag>` to `</tag>\n`, handling nested tags
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# in between.
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<($block_tags_b_re) # start tag = $2
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$attr> # attributes followed by > and \n
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$content # content, support nesting
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</\2> # the matching end tag
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[ ]* # trailing spaces
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(?=\n+|\Z) # followed by a newline or end of document
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|
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| # Special version for tags of group a.
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<($block_tags_a_re) # start tag = $3
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$attr>[ ]*\n # attributes followed by >
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$content2 # content, support nesting
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</\3> # the matching end tag
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[ ]* # trailing spaces
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(?=\n+|\Z) # followed by a newline or end of document
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|
|
| # Special case just for <hr />. It was easier to make a special
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# case than to make the other regex more complicated.
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[ ]{0,$less_than_tab}
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<hr
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$attr # attributes
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/?> # the matching end tag
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[ ]*
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(?=\n{2,}|\Z) # followed by a blank line or end of document
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|
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| # Special case for standalone HTML comments:
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|
|
(?<=\n\n|\A) # preceded by a blank line or start of document
|
|
[ ]{0,$less_than_tab}
|
|
(?s:
|
|
<!--(?:|(?:[^>-]|-[^>])(?:[^-]|-[^-])*)-->
|
|
)
|
|
[ ]*
|
|
(?=\n{2,}|\Z) # followed by a blank line or end of document
|
|
|
|
| # PHP and ASP-style processor instructions (<? and <%)
|
|
|
|
[ ]{0,$less_than_tab}
|
|
(?s:
|
|
<([?%]) # $4
|
|
.*?
|
|
\4>
|
|
)
|
|
[ ]*
|
|
(?=\n{2,}|\Z) # followed by a blank line or end of document
|
|
|
|
)
|
|
)";
|
|
|
|
pattern = pattern.Replace("$less_than_tab", (_tabWidth - 1).ToString());
|
|
pattern = pattern.Replace("$block_tags_b_re", blockTagsB);
|
|
pattern = pattern.Replace("$block_tags_a_re", blockTagsA);
|
|
pattern = pattern.Replace("$attr", attr);
|
|
pattern = pattern.Replace("$content2", content2);
|
|
return pattern.Replace("$content", content);
|
|
}
|
|
|
|
/// <summary>
|
|
/// replaces any block-level HTML blocks with hash entries
|
|
/// </summary>
|
|
private string HashHTMLBlocks(string text)
|
|
{
|
|
return _blocksHtml.Replace(text, new MatchEvaluator(HtmlEvaluator));
|
|
}
|
|
|
|
private string HtmlEvaluator(Match match)
|
|
{
|
|
string text = match.Groups[1].Value;
|
|
string key = GetHashKey(text, isHtmlBlock: true);
|
|
_htmlBlocks[key] = text;
|
|
|
|
return string.Concat("\n\n", key, "\n\n");
|
|
}
|
|
|
|
private static string GetHashKey(string s, bool isHtmlBlock)
|
|
{
|
|
var delim = isHtmlBlock ? 'H' : 'E';
|
|
return "\x1A" + delim + Math.Abs(s.GetHashCode()).ToString() + delim;
|
|
}
|
|
|
|
private static readonly Regex _htmlTokens = new Regex(@"
|
|
(<!--(?:|(?:[^>-]|-[^>])(?:[^-]|-[^-])*)-->)| # match <!-- foo -->
|
|
(<\?.*?\?>)| # match <?foo?> " +
|
|
RepeatString(@"
|
|
(<[A-Za-z\/!$](?:[^<>]|", _nestDepth - 1) + @"
|
|
(<[A-Za-z\/!$](?:[^<>]"
|
|
+ RepeatString(")*>)", _nestDepth) +
|
|
" # match <tag> and </tag>",
|
|
RegexOptions.Multiline | RegexOptions.Singleline | RegexOptions.ExplicitCapture | RegexOptions.IgnorePatternWhitespace | RegexOptions.Compiled);
|
|
|
|
/// <summary>
|
|
/// returns an array of HTML tokens comprising the input string. Each token is
|
|
/// either a tag (possibly with nested, tags contained therein, such
|
|
/// as <a href="<MTFoo>">, or a run of text between tags. Each element of the
|
|
/// array is a two-element array; the first is either 'tag' or 'text'; the second is
|
|
/// the actual value.
|
|
/// </summary>
|
|
private List<Token> TokenizeHTML(string text)
|
|
{
|
|
int pos = 0;
|
|
int tagStart = 0;
|
|
var tokens = new List<Token>();
|
|
|
|
// this regex is derived from the _tokenize() subroutine in Brad Choate's MTRegex plugin.
|
|
// http://www.bradchoate.com/past/mtregex.php
|
|
foreach (Match m in _htmlTokens.Matches(text))
|
|
{
|
|
tagStart = m.Index;
|
|
|
|
if (pos < tagStart)
|
|
tokens.Add(new Token(TokenType.Text, text.Substring(pos, tagStart - pos)));
|
|
|
|
tokens.Add(new Token(TokenType.Tag, m.Value));
|
|
pos = tagStart + m.Length;
|
|
}
|
|
|
|
if (pos < text.Length)
|
|
tokens.Add(new Token(TokenType.Text, text.Substring(pos, text.Length - pos)));
|
|
|
|
return tokens;
|
|
}
|
|
|
|
private static readonly Regex _anchorRef = new Regex(string.Format(@"
|
|
( # wrap whole match in $1
|
|
\[
|
|
({0}) # link text = $2
|
|
\]
|
|
|
|
[ ]? # one optional space
|
|
(?:\n[ ]*)? # one optional newline followed by spaces
|
|
|
|
\[
|
|
(.*?) # id = $3
|
|
\]
|
|
)", GetNestedBracketsPattern()), RegexOptions.IgnorePatternWhitespace | RegexOptions.Compiled);
|
|
|
|
private static readonly Regex _anchorInline = new Regex(string.Format(@"
|
|
( # wrap whole match in $1
|
|
\[
|
|
({0}) # link text = $2
|
|
\]
|
|
\( # literal paren
|
|
[ ]*
|
|
({1}) # href = $3
|
|
[ ]*
|
|
( # $4
|
|
(['""]) # quote char = $5
|
|
(.*?) # title = $6
|
|
\5 # matching quote
|
|
[ ]* # ignore any spaces between closing quote and )
|
|
)? # title is optional
|
|
\)
|
|
)", GetNestedBracketsPattern(), GetNestedParensPattern()),
|
|
RegexOptions.IgnorePatternWhitespace | RegexOptions.Compiled);
|
|
|
|
private static readonly Regex _anchorRefShortcut = new Regex(@"
|
|
( # wrap whole match in $1
|
|
\[
|
|
([^\[\]]+) # link text = $2; can't contain [ or ]
|
|
\]
|
|
)", RegexOptions.IgnorePatternWhitespace | RegexOptions.Compiled);
|
|
|
|
/// <summary>
|
|
/// Turn Markdown link shortcuts into HTML anchor tags
|
|
/// </summary>
|
|
/// <remarks>
|
|
/// [link text](url "title")
|
|
/// [link text][id]
|
|
/// [id]
|
|
/// </remarks>
|
|
private string DoAnchors(string text)
|
|
{
|
|
if (!text.Contains("["))
|
|
return text;
|
|
|
|
// First, handle reference-style links: [link text] [id]
|
|
text = _anchorRef.Replace(text, new MatchEvaluator(AnchorRefEvaluator));
|
|
|
|
// Next, inline-style links: [link text](url "optional title") or [link text](url "optional title")
|
|
text = _anchorInline.Replace(text, new MatchEvaluator(AnchorInlineEvaluator));
|
|
|
|
// Last, handle reference-style shortcuts: [link text]
|
|
// These must come last in case you've also got [link test][1]
|
|
// or [link test](/foo)
|
|
return _anchorRefShortcut.Replace(text, new MatchEvaluator(AnchorRefShortcutEvaluator));
|
|
}
|
|
|
|
private string SaveFromAutoLinking(string s)
|
|
{
|
|
return s.Replace("://", AutoLinkPreventionMarker);
|
|
}
|
|
|
|
private string AnchorRefEvaluator(Match match)
|
|
{
|
|
string wholeMatch = match.Groups[1].Value;
|
|
string linkText = SaveFromAutoLinking(match.Groups[2].Value);
|
|
string linkID = match.Groups[3].Value.ToLowerInvariant();
|
|
|
|
string result;
|
|
|
|
// for shortcut links like [this][].
|
|
if (linkID?.Length == 0)
|
|
linkID = linkText.ToLowerInvariant();
|
|
|
|
if (_urls.ContainsKey(linkID))
|
|
{
|
|
string url = _urls[linkID];
|
|
|
|
url = AttributeSafeUrl(url);
|
|
|
|
result = "<a href=\"" + url + "\"";
|
|
|
|
if (_titles.ContainsKey(linkID))
|
|
{
|
|
string title = AttributeEncode(_titles[linkID]);
|
|
title = AttributeEncode(EscapeBoldItalic(title));
|
|
result += " title=\"" + title + "\"";
|
|
}
|
|
|
|
result += ">" + linkText + "</a>";
|
|
}
|
|
else
|
|
{
|
|
result = wholeMatch;
|
|
}
|
|
|
|
return result;
|
|
}
|
|
|
|
private string AnchorRefShortcutEvaluator(Match match)
|
|
{
|
|
string wholeMatch = match.Groups[1].Value;
|
|
string linkText = SaveFromAutoLinking(match.Groups[2].Value);
|
|
string linkID = Regex.Replace(linkText.ToLowerInvariant(), @"[ ]*\n[ ]*", " "); // lower case and remove newlines / extra spaces
|
|
|
|
string result;
|
|
|
|
if (_urls.ContainsKey(linkID))
|
|
{
|
|
string url = _urls[linkID];
|
|
|
|
url = AttributeSafeUrl(url);
|
|
|
|
result = "<a href=\"" + url + "\"";
|
|
|
|
if (_titles.ContainsKey(linkID))
|
|
{
|
|
string title = AttributeEncode(_titles[linkID]);
|
|
title = EscapeBoldItalic(title);
|
|
result += " title=\"" + title + "\"";
|
|
}
|
|
|
|
result += ">" + linkText + "</a>";
|
|
}
|
|
else
|
|
{
|
|
result = wholeMatch;
|
|
}
|
|
|
|
return result;
|
|
}
|
|
|
|
private string AnchorInlineEvaluator(Match match)
|
|
{
|
|
string linkText = SaveFromAutoLinking(match.Groups[2].Value);
|
|
string url = match.Groups[3].Value;
|
|
string title = match.Groups[6].Value;
|
|
string result;
|
|
|
|
if (url.StartsWith("<") && url.EndsWith(">"))
|
|
url = url.Substring(1, url.Length - 2); // remove <>'s surrounding URL, if present
|
|
|
|
url = AttributeSafeUrl(url);
|
|
|
|
result = string.Format("<a href=\"{0}\"", url);
|
|
|
|
if (!string.IsNullOrEmpty(title))
|
|
{
|
|
title = AttributeEncode(title);
|
|
title = EscapeBoldItalic(title);
|
|
result += string.Format(" title=\"{0}\"", title);
|
|
}
|
|
|
|
result += string.Format(">{0}</a>", linkText);
|
|
return result;
|
|
}
|
|
|
|
private static readonly Regex _imagesRef = new Regex(@"
|
|
( # wrap whole match in $1
|
|
!\[
|
|
(.*?) # alt text = $2
|
|
\]
|
|
|
|
[ ]? # one optional space
|
|
(?:\n[ ]*)? # one optional newline followed by spaces
|
|
|
|
\[
|
|
(.*?) # id = $3
|
|
\]
|
|
|
|
)", RegexOptions.IgnorePatternWhitespace | RegexOptions.Compiled);
|
|
|
|
private static readonly Regex _imagesInline = new Regex(string.Format(@"
|
|
( # wrap whole match in $1
|
|
!\[
|
|
(.*?) # alt text = $2
|
|
\]
|
|
\s? # one optional whitespace character
|
|
\( # literal paren
|
|
[ ]*
|
|
({0}) # href = $3
|
|
[ ]*
|
|
( # $4
|
|
(['""]) # quote char = $5
|
|
(.*?) # title = $6
|
|
\5 # matching quote
|
|
[ ]*
|
|
)? # title is optional
|
|
\)
|
|
)", GetNestedParensPattern()),
|
|
RegexOptions.IgnorePatternWhitespace | RegexOptions.Compiled);
|
|
|
|
/// <summary>
|
|
/// Turn Markdown image shortcuts into HTML img tags.
|
|
/// </summary>
|
|
/// <remarks>
|
|
/// ![alt text][id]
|
|
/// 
|
|
/// </remarks>
|
|
private string DoImages(string text)
|
|
{
|
|
if (!text.Contains("!["))
|
|
return text;
|
|
|
|
// First, handle reference-style labeled images: ![alt text][id]
|
|
text = _imagesRef.Replace(text, new MatchEvaluator(ImageReferenceEvaluator));
|
|
|
|
// Next, handle inline images: 
|
|
// Don't forget: encode * and _
|
|
return _imagesInline.Replace(text, new MatchEvaluator(ImageInlineEvaluator));
|
|
}
|
|
|
|
// This prevents the creation of horribly broken HTML when some syntax ambiguities
|
|
// collide. It likely still doesn't do what the user meant, but at least we're not
|
|
// outputting garbage.
|
|
private string EscapeImageAltText(string s)
|
|
{
|
|
s = EscapeBoldItalic(s);
|
|
return Regex.Replace(s, @"[\[\]()]", m => _escapeTable[m.ToString()]);
|
|
}
|
|
|
|
private string ImageReferenceEvaluator(Match match)
|
|
{
|
|
string wholeMatch = match.Groups[1].Value;
|
|
string altText = match.Groups[2].Value;
|
|
string linkID = match.Groups[3].Value.ToLowerInvariant();
|
|
|
|
// for shortcut links like ![this][].
|
|
if (linkID?.Length == 0)
|
|
linkID = altText.ToLowerInvariant();
|
|
|
|
if (_urls.ContainsKey(linkID))
|
|
{
|
|
string url = _urls[linkID];
|
|
string title = null;
|
|
|
|
if (_titles.ContainsKey(linkID))
|
|
title = _titles[linkID];
|
|
|
|
return ImageTag(url, altText, title);
|
|
}
|
|
else
|
|
{
|
|
// If there's no such link ID, leave intact:
|
|
return wholeMatch;
|
|
}
|
|
}
|
|
|
|
private string ImageInlineEvaluator(Match match)
|
|
{
|
|
string alt = match.Groups[2].Value;
|
|
string url = match.Groups[3].Value;
|
|
string title = match.Groups[6].Value;
|
|
|
|
if (url.StartsWith("<") && url.EndsWith(">"))
|
|
url = url.Substring(1, url.Length - 2); // Remove <>'s surrounding URL, if present
|
|
|
|
return ImageTag(url, alt, title);
|
|
}
|
|
|
|
private string ImageTag(string url, string altText, string title)
|
|
{
|
|
altText = EscapeImageAltText(AttributeEncode(altText));
|
|
url = AttributeSafeUrl(url);
|
|
var result = string.Format("<img src=\"{0}\" alt=\"{1}\"", url, altText);
|
|
if (!string.IsNullOrEmpty(title))
|
|
{
|
|
title = AttributeEncode(EscapeBoldItalic(title));
|
|
result += string.Format(" title=\"{0}\"", title);
|
|
}
|
|
result += EmptyElementSuffix;
|
|
return result;
|
|
}
|
|
|
|
private static readonly Regex _headerSetext = new Regex(@"
|
|
^(.+?)
|
|
[ ]*
|
|
\n
|
|
(=+|-+) # $1 = string of ='s or -'s
|
|
[ ]*
|
|
\n+",
|
|
RegexOptions.Multiline | RegexOptions.IgnorePatternWhitespace | RegexOptions.Compiled);
|
|
|
|
private static readonly Regex _headerAtx = new Regex(@"
|
|
^(\#{1,6}) # $1 = string of #'s
|
|
[ ]*
|
|
(.+?) # $2 = Header text
|
|
[ ]*
|
|
\#* # optional closing #'s (not counted)
|
|
\n+",
|
|
RegexOptions.Multiline | RegexOptions.IgnorePatternWhitespace | RegexOptions.Compiled);
|
|
|
|
/// <summary>
|
|
/// Turn Markdown headers into HTML header tags
|
|
/// </summary>
|
|
/// <remarks>
|
|
/// <para>
|
|
/// Header 1
|
|
/// ========
|
|
/// </para>
|
|
/// <para>
|
|
/// Header 2
|
|
/// --------
|
|
/// </para>
|
|
/// <para>
|
|
/// # Header 1
|
|
/// ## Header 2
|
|
/// ## Header 2 with closing hashes ##
|
|
/// ...
|
|
/// ###### Header 6
|
|
/// </para>
|
|
/// </remarks>
|
|
private string DoHeaders(string text)
|
|
{
|
|
text = _headerSetext.Replace(text, new MatchEvaluator(SetextHeaderEvaluator));
|
|
return _headerAtx.Replace(text, new MatchEvaluator(AtxHeaderEvaluator));
|
|
}
|
|
|
|
private string SetextHeaderEvaluator(Match match)
|
|
{
|
|
string header = match.Groups[1].Value;
|
|
int level = match.Groups[2].Value.StartsWith("=") ? 1 : 2;
|
|
return string.Format("<h{1}>{0}</h{1}>\n\n", RunSpanGamut(header), level);
|
|
}
|
|
|
|
private string AtxHeaderEvaluator(Match match)
|
|
{
|
|
string header = match.Groups[2].Value;
|
|
int level = match.Groups[1].Value.Length;
|
|
return string.Format("<h{1}>{0}</h{1}>\n\n", RunSpanGamut(header), level);
|
|
}
|
|
|
|
private static readonly Regex _horizontalRules = new Regex(@"
|
|
^[ ]{0,3} # Leading space
|
|
([-*_]) # $1: First marker
|
|
(?> # Repeated marker group
|
|
[ ]{0,2} # Zero, one, or two spaces.
|
|
\1 # Marker character
|
|
){2,} # Group repeated at least twice
|
|
[ ]* # Trailing spaces
|
|
$ # End of line.
|
|
", RegexOptions.Multiline | RegexOptions.IgnorePatternWhitespace | RegexOptions.Compiled);
|
|
|
|
/// <summary>
|
|
/// Turn Markdown horizontal rules into HTML hr tags
|
|
/// </summary>
|
|
/// <remarks>
|
|
/// ***
|
|
/// * * *
|
|
/// ---
|
|
/// - - -
|
|
/// </remarks>
|
|
private string DoHorizontalRules(string text)
|
|
{
|
|
return _horizontalRules.Replace(text, "<hr" + EmptyElementSuffix + "\n");
|
|
}
|
|
|
|
private static readonly string _wholeList = string.Format(@"
|
|
( # $1 = whole list
|
|
( # $2
|
|
[ ]{{0,{1}}}
|
|
({0}) # $3 = first list item marker
|
|
[ ]+
|
|
)
|
|
(?s:.+?)
|
|
( # $4
|
|
\z
|
|
|
|
|
\n{{2,}}
|
|
(?=\S)
|
|
(?! # Negative lookahead for another list item marker
|
|
[ ]*
|
|
{0}[ ]+
|
|
)
|
|
)
|
|
)", string.Format("(?:{0}|{1})", _markerUL, _markerOL), _tabWidth - 1);
|
|
|
|
private static readonly Regex _listNested = new Regex("^" + _wholeList,
|
|
RegexOptions.Multiline | RegexOptions.IgnorePatternWhitespace | RegexOptions.Compiled);
|
|
|
|
private static readonly Regex _listTopLevel = new Regex(@"(?:(?<=\n\n)|\A\n?)" + _wholeList,
|
|
RegexOptions.Multiline | RegexOptions.IgnorePatternWhitespace | RegexOptions.Compiled);
|
|
|
|
/// <summary>
|
|
/// Turn Markdown lists into HTML ul and ol and li tags
|
|
/// </summary>
|
|
private string DoLists(string text)
|
|
{
|
|
// We use a different prefix before nested lists than top-level lists.
|
|
// See extended comment in _ProcessListItems().
|
|
if (_listLevel > 0)
|
|
{
|
|
return _listNested.Replace(text, new MatchEvaluator(ListEvaluator));
|
|
}
|
|
else
|
|
{
|
|
return _listTopLevel.Replace(text, new MatchEvaluator(ListEvaluator));
|
|
}
|
|
}
|
|
|
|
private string ListEvaluator(Match match)
|
|
{
|
|
string list = match.Groups[1].Value;
|
|
string marker = match.Groups[3].Value;
|
|
string listType = Regex.IsMatch(marker, _markerUL) ? "ul" : "ol";
|
|
string result;
|
|
string start = "";
|
|
if (listType == "ol")
|
|
{
|
|
int.TryParse(marker.Substring(0, marker.Length - 1), out int firstNumber);
|
|
if (firstNumber != 1 && firstNumber != 0)
|
|
start = " start=\"" + firstNumber + "\"";
|
|
}
|
|
|
|
result = ProcessListItems(list, listType == "ul" ? _markerUL : _markerOL);
|
|
|
|
return string.Format("<{0}{1}>\n{2}</{0}>\n", listType, start, result);
|
|
}
|
|
|
|
/// <summary>
|
|
/// Process the contents of a single ordered or unordered list, splitting it
|
|
/// into individual list items.
|
|
/// </summary>
|
|
private string ProcessListItems(string list, string marker)
|
|
{
|
|
// The listLevel global keeps track of when we're inside a list.
|
|
// Each time we enter a list, we increment it; when we leave a list,
|
|
// we decrement. If it's zero, we're not in a list anymore.
|
|
|
|
// We do this because when we're not inside a list, we want to treat
|
|
// something like this:
|
|
|
|
// I recommend upgrading to version
|
|
// 8. Oops, now this line is treated
|
|
// as a sub-list.
|
|
|
|
// As a single paragraph, despite the fact that the second line starts
|
|
// with a digit-period-space sequence.
|
|
|
|
// Whereas when we're inside a list (or sub-list), that line will be
|
|
// treated as the start of a sub-list. What a kludge, huh? This is
|
|
// an aspect of Markdown's syntax that's hard to parse perfectly
|
|
// without resorting to mind-reading. Perhaps the solution is to
|
|
// change the syntax rules such that sub-lists must start with a
|
|
// starting cardinal number; e.g. "1." or "a.".
|
|
|
|
_listLevel++;
|
|
|
|
// Trim trailing blank lines:
|
|
list = Regex.Replace(list, @"\n{2,}\z", "\n");
|
|
|
|
string pattern = string.Format(
|
|
@"(^[ ]*) # leading whitespace = $1
|
|
({0}) [ ]+ # list marker = $2
|
|
((?s:.+?) # list item text = $3
|
|
(\n+))
|
|
(?= (\z | \1 ({0}) [ ]+))", marker);
|
|
|
|
bool lastItemHadADoubleNewline = false;
|
|
|
|
// has to be a closure, so subsequent invocations can share the bool
|
|
string ListItemEvaluator(Match match)
|
|
{
|
|
string item = match.Groups[3].Value;
|
|
|
|
bool endsWithDoubleNewline = item.EndsWith("\n\n");
|
|
bool containsDoubleNewline = endsWithDoubleNewline || item.Contains("\n\n");
|
|
|
|
var loose = containsDoubleNewline || lastItemHadADoubleNewline;
|
|
// we could correct any bad indentation here..
|
|
item = RunBlockGamut(Outdent(item) + "\n", unhash: false, createParagraphs: loose);
|
|
|
|
lastItemHadADoubleNewline = endsWithDoubleNewline;
|
|
return string.Format("<li>{0}</li>\n", item);
|
|
}
|
|
|
|
list = Regex.Replace(list, pattern, new MatchEvaluator(ListItemEvaluator),
|
|
RegexOptions.IgnorePatternWhitespace | RegexOptions.Multiline);
|
|
_listLevel--;
|
|
return list;
|
|
}
|
|
|
|
private static readonly Regex _codeBlock = new Regex(string.Format(@"
|
|
(?:\n\n|\A\n?)
|
|
( # $1 = the code block -- one or more lines, starting with a space
|
|
(?:
|
|
(?:[ ]{{{0}}}) # Lines must start with a tab-width of spaces
|
|
.*\n+
|
|
)+
|
|
)
|
|
((?=^[ ]{{0,{0}}}[^ \t\n])|\Z) # Lookahead for non-space at line-start, or end of doc",
|
|
_tabWidth), RegexOptions.Multiline | RegexOptions.IgnorePatternWhitespace | RegexOptions.Compiled);
|
|
|
|
/// <summary>
|
|
/// /// Turn Markdown 4-space indented code into HTML pre code blocks
|
|
/// </summary>
|
|
private string DoCodeBlocks(string text)
|
|
{
|
|
return _codeBlock.Replace(text, new MatchEvaluator(CodeBlockEvaluator));
|
|
}
|
|
|
|
private string CodeBlockEvaluator(Match match)
|
|
{
|
|
string codeBlock = match.Groups[1].Value;
|
|
|
|
codeBlock = EncodeCode(Outdent(codeBlock));
|
|
codeBlock = _newlinesLeadingTrailing.Replace(codeBlock, "");
|
|
|
|
return string.Concat("\n\n<pre><code>", codeBlock, "\n</code></pre>\n\n");
|
|
}
|
|
|
|
private static readonly Regex _codeSpan = new Regex(@"
|
|
(?<![\\`]) # Character before opening ` can't be a backslash or backtick
|
|
(`+) # $1 = Opening run of `
|
|
(?!`) # and no more backticks -- match the full run
|
|
(.+?) # $2 = The code block
|
|
(?<!`)
|
|
\1
|
|
(?!`)", RegexOptions.IgnorePatternWhitespace | RegexOptions.Singleline | RegexOptions.Compiled);
|
|
|
|
/// <summary>
|
|
/// Turn Markdown `code spans` into HTML code tags
|
|
/// </summary>
|
|
private string DoCodeSpans(string text)
|
|
{
|
|
// * You can use multiple backticks as the delimiters if you want to
|
|
// include literal backticks in the code span. So, this input:
|
|
//
|
|
// Just type ``foo `bar` baz`` at the prompt.
|
|
//
|
|
// Will translate to:
|
|
//
|
|
// <p>Just type <code>foo `bar` baz</code> at the prompt.</p>
|
|
//
|
|
// There's no arbitrary limit to the number of backticks you
|
|
// can use as delimters. If you need three consecutive backticks
|
|
// in your code, use four for delimiters, etc.
|
|
//
|
|
// * You can use spaces to get literal backticks at the edges:
|
|
//
|
|
// ... type `` `bar` `` ...
|
|
//
|
|
// Turns to:
|
|
//
|
|
// ... type <code>`bar`</code> ...
|
|
//
|
|
|
|
return _codeSpan.Replace(text, new MatchEvaluator(CodeSpanEvaluator));
|
|
}
|
|
|
|
private string CodeSpanEvaluator(Match match)
|
|
{
|
|
string span = match.Groups[2].Value;
|
|
span = Regex.Replace(span, "^[ ]*", ""); // leading whitespace
|
|
span = Regex.Replace(span, "[ ]*$", ""); // trailing whitespace
|
|
span = EncodeCode(span);
|
|
span = SaveFromAutoLinking(span); // to prevent auto-linking. Not necessary in code *blocks*, but in code spans.
|
|
|
|
return string.Concat("<code>", span, "</code>");
|
|
}
|
|
|
|
private static readonly Regex _bold = new Regex(@"(\*\*|__) (?=\S) (.+?[*_]*) (?<=\S) \1",
|
|
RegexOptions.IgnorePatternWhitespace | RegexOptions.Singleline | RegexOptions.Compiled);
|
|
|
|
private static readonly Regex _semiStrictBold = new Regex(@"(?=.[*_]|[*_])(^|(?=\W__|(?!\*)[\W_]\*\*|\w\*\*\w).)(\*\*|__)(?!\2)(?=\S)((?:|.*?(?!\2).)(?=\S_|\w|\S\*\*(?:[\W_]|$)).)(?=__(?:\W|$)|\*\*(?:[^*]|$))\2",
|
|
RegexOptions.Singleline | RegexOptions.Compiled);
|
|
|
|
private static readonly Regex _strictBold = new Regex(@"(^|[\W_])(?:(?!\1)|(?=^))(\*|_)\2(?=\S)(.*?\S)\2\2(?!\2)(?=[\W_]|$)",
|
|
RegexOptions.Singleline | RegexOptions.Compiled);
|
|
|
|
private static readonly Regex _italic = new Regex(@"(\*|_) (?=\S) (.+?) (?<=\S) \1",
|
|
RegexOptions.IgnorePatternWhitespace | RegexOptions.Singleline | RegexOptions.Compiled);
|
|
|
|
private static readonly Regex _semiStrictItalic = new Regex(@"(?=.[*_]|[*_])(^|(?=\W_|(?!\*)(?:[\W_]\*|\D\*(?=\w)\D)).)(\*|_)(?!\2\2\2)(?=\S)((?:(?!\2).)*?(?=[^\s_]_|(?=\w)\D\*\D|[^\s*]\*(?:[\W_]|$)).)(?=_(?:\W|$)|\*(?:[^*]|$))\2",
|
|
RegexOptions.Singleline | RegexOptions.Compiled);
|
|
|
|
private static readonly Regex _strictItalic = new Regex(@"(^|[\W_])(?:(?!\1)|(?=^))(\*|_)(?=\S)((?:(?!\2).)*?\S)\2(?!\2)(?=[\W_]|$)",
|
|
RegexOptions.Singleline | RegexOptions.Compiled);
|
|
|
|
/// <summary>
|
|
/// Turn Markdown *italics* and **bold** into HTML strong and em tags
|
|
/// </summary>
|
|
private string DoItalicsAndBold(string text)
|
|
{
|
|
if (!(text.Contains("*") || text.Contains("_")))
|
|
return text;
|
|
// <strong> must go first, then <em>
|
|
if (StrictBoldItalic)
|
|
{
|
|
if (AsteriskIntraWordEmphasis)
|
|
{
|
|
text = _semiStrictBold.Replace(text, "$1<strong>$3</strong>");
|
|
text = _semiStrictItalic.Replace(text, "$1<em>$3</em>");
|
|
}
|
|
else
|
|
{
|
|
text = _strictBold.Replace(text, "$1<strong>$3</strong>");
|
|
text = _strictItalic.Replace(text, "$1<em>$3</em>");
|
|
}
|
|
}
|
|
else
|
|
{
|
|
text = _bold.Replace(text, "<strong>$2</strong>");
|
|
text = _italic.Replace(text, "<em>$2</em>");
|
|
}
|
|
return text;
|
|
}
|
|
|
|
/// <summary>
|
|
/// Turn markdown line breaks (two space at end of line) into HTML break tags
|
|
/// </summary>
|
|
private string DoHardBreaks(string text)
|
|
{
|
|
if (AutoNewLines)
|
|
{
|
|
return Regex.Replace(text, @"\n", string.Format("<br{0}\n", EmptyElementSuffix));
|
|
}
|
|
else
|
|
{
|
|
return Regex.Replace(text, @" {2,}\n", string.Format("<br{0}\n", EmptyElementSuffix));
|
|
}
|
|
}
|
|
|
|
private static readonly Regex _blockquote = new Regex(@"
|
|
( # Wrap whole match in $1
|
|
(
|
|
^[ ]*>[ ]? # '>' at the start of a line
|
|
.+\n # rest of the first line
|
|
(.+\n)* # subsequent consecutive lines
|
|
\n* # blanks
|
|
)+
|
|
)", RegexOptions.IgnorePatternWhitespace | RegexOptions.Multiline | RegexOptions.Compiled);
|
|
|
|
/// <summary>
|
|
/// Turn Markdown > quoted blocks into HTML blockquote blocks
|
|
/// </summary>
|
|
private string DoBlockQuotes(string text)
|
|
{
|
|
return _blockquote.Replace(text, new MatchEvaluator(BlockQuoteEvaluator));
|
|
}
|
|
|
|
private string BlockQuoteEvaluator(Match match)
|
|
{
|
|
string bq = match.Groups[1].Value;
|
|
|
|
bq = Regex.Replace(bq, "^[ ]*>[ ]?", "", RegexOptions.Multiline); // trim one level of quoting
|
|
bq = Regex.Replace(bq, "^[ ]+$", "", RegexOptions.Multiline); // trim whitespace-only lines
|
|
bq = RunBlockGamut(bq); // recurse
|
|
|
|
bq = Regex.Replace(bq, "^", " ", RegexOptions.Multiline);
|
|
|
|
// These leading spaces screw with <pre> content, so we need to fix that:
|
|
bq = Regex.Replace(bq, @"(\s*<pre>.+?</pre>)", new MatchEvaluator(BlockQuoteEvaluator2), RegexOptions.IgnorePatternWhitespace | RegexOptions.Singleline);
|
|
|
|
bq = string.Format("<blockquote>\n{0}\n</blockquote>", bq);
|
|
string key = GetHashKey(bq, isHtmlBlock: true);
|
|
_htmlBlocks[key] = bq;
|
|
|
|
return "\n\n" + key + "\n\n";
|
|
}
|
|
|
|
private string BlockQuoteEvaluator2(Match match)
|
|
{
|
|
return Regex.Replace(match.Groups[1].Value, "^ ", "", RegexOptions.Multiline);
|
|
}
|
|
|
|
private const string _charInsideUrl = @"[-A-Z0-9+&@#/%?=~_|\[\]\(\)!:,\.;" + "\x1a]";
|
|
private const string _charEndingUrl = "[-A-Z0-9+&@#/%=~_|\\[\\])]";
|
|
|
|
private static readonly Regex _autolinkBare = new Regex(@"(<|="")?\b(https?|ftp)(://" + _charInsideUrl + "*" + _charEndingUrl + ")(?=$|\\W)",
|
|
RegexOptions.IgnoreCase | RegexOptions.Compiled);
|
|
|
|
private static readonly Regex _endCharRegex = new Regex(_charEndingUrl, RegexOptions.IgnoreCase | RegexOptions.Compiled);
|
|
|
|
private static string HandleTrailingParens(Match match)
|
|
{
|
|
// The first group is essentially a negative lookbehind -- if there's a < or a =", we don't touch this.
|
|
// We're not using a *real* lookbehind, because of links with in links, like <a href="http://web.archive.org/web/20121130000728/http://www.google.com/">
|
|
// With a real lookbehind, the full link would never be matched, and thus the http://www.google.com *would* be matched.
|
|
// With the simulated lookbehind, the full link *is* matched (just not handled, because of this early return), causing
|
|
// the google link to not be matched again.
|
|
if (match.Groups[1].Success)
|
|
return match.Value;
|
|
|
|
var protocol = match.Groups[2].Value;
|
|
var link = match.Groups[3].Value;
|
|
if (!link.EndsWith(")"))
|
|
return "<" + protocol + link + ">";
|
|
var level = 0;
|
|
foreach (Match c in Regex.Matches(link, "[()]"))
|
|
{
|
|
if (c.Value == "(")
|
|
{
|
|
if (level <= 0)
|
|
level = 1;
|
|
else
|
|
level++;
|
|
}
|
|
else
|
|
{
|
|
level--;
|
|
}
|
|
}
|
|
var tail = "";
|
|
if (level < 0)
|
|
{
|
|
link = Regex.Replace(link, @"\){1," + (-level) + "}$", m => { tail = m.Value; return ""; });
|
|
}
|
|
if (tail.Length > 0)
|
|
{
|
|
var lastChar = link[link.Length - 1];
|
|
if (!_endCharRegex.IsMatch(lastChar.ToString()))
|
|
{
|
|
tail = lastChar + tail;
|
|
link = link.Substring(0, link.Length - 1);
|
|
}
|
|
}
|
|
return "<" + protocol + link + ">" + tail;
|
|
}
|
|
|
|
private static readonly Regex _autoEmailBare = new Regex(@"(<|="")?(?:mailto:)?([-.\w]+\@[-a-z0-9]+(\.[-a-z0-9]+)*\.[a-z]+)", RegexOptions.IgnoreCase | RegexOptions.Compiled);
|
|
|
|
private static string EmailBareLinkEvaluator(Match match)
|
|
{
|
|
// We matched an opening <, so it's already enclosed
|
|
if (match.Groups[1].Success)
|
|
{
|
|
return match.Value;
|
|
}
|
|
return "<" + match.Value + ">";
|
|
}
|
|
|
|
private readonly static Regex _linkEmail = new Regex(@"<
|
|
(?:mailto:)?
|
|
(
|
|
[-.\w]+
|
|
\@
|
|
[-a-z0-9]+(\.[-a-z0-9]+)*\.[a-z]+
|
|
)
|
|
>", RegexOptions.IgnoreCase | RegexOptions.IgnorePatternWhitespace);
|
|
|
|
/// <summary>
|
|
/// Turn angle-delimited URLs into HTML anchor tags
|
|
/// </summary>
|
|
/// <remarks>
|
|
/// <http://www.example.com>
|
|
/// </remarks>
|
|
private string DoAutoLinks(string text)
|
|
{
|
|
if (AutoHyperlink)
|
|
{
|
|
// fixup arbitrary URLs by adding Markdown < > so they get linked as well
|
|
// note that at this point, all other URL in the text are already hyperlinked as <a href=""></a>
|
|
// *except* for the <http://www.foo.com> case
|
|
text = _autolinkBare.Replace(text, HandleTrailingParens);
|
|
}
|
|
|
|
// Hyperlinks: <http://foo.com>
|
|
text = Regex.Replace(text, "<((https?|ftp):[^'\">\\s]+)>", new MatchEvaluator(HyperlinkEvaluator));
|
|
|
|
if (LinkEmails)
|
|
{
|
|
// Email addresses: <address@domain.foo> or <mailto:address@domain.foo>
|
|
// Also allow "address@domain.foo" and "mailto:address@domain.foo", without the <>
|
|
//text = _autoEmailBare.Replace(text, EmailBareLinkEvaluator);
|
|
text = _linkEmail.Replace(text, new MatchEvaluator(EmailEvaluator));
|
|
}
|
|
|
|
return text;
|
|
}
|
|
|
|
private string HyperlinkEvaluator(Match match)
|
|
{
|
|
string link = match.Groups[1].Value;
|
|
string url = AttributeSafeUrl(link);
|
|
return string.Format("<a href=\"{0}\">{1}</a>", url, link);
|
|
}
|
|
|
|
private string EmailEvaluator(Match match)
|
|
{
|
|
string email = Unescape(match.Groups[1].Value);
|
|
|
|
//
|
|
// Input: an email address, e.g. "foo@example.com"
|
|
//
|
|
// Output: the email address as a mailto link, with each character
|
|
// of the address encoded as either a decimal or hex entity, in
|
|
// the hopes of foiling most address harvesting spam bots. E.g.:
|
|
//
|
|
// <a href="mailto:foo@e
|
|
// xample.com">foo
|
|
// @example.com</a>
|
|
//
|
|
// Based by a filter by Matthew Wickline, posted to the BBEdit-Talk
|
|
// mailing list: <http://tinyurl.com/yu7ue>
|
|
//
|
|
email = "mailto:" + email;
|
|
|
|
// leave ':' alone (to spot mailto: later)
|
|
email = EncodeEmailAddress(email);
|
|
|
|
email = string.Format("<a href=\"{0}\">{0}</a>", email);
|
|
|
|
// strip the mailto: from the visible part
|
|
return Regex.Replace(email, "\">.+?:", "\">");
|
|
}
|
|
|
|
private static readonly Regex _outDent = new Regex("^[ ]{1," + _tabWidth + "}", RegexOptions.Multiline | RegexOptions.Compiled);
|
|
|
|
/// <summary>
|
|
/// Remove one level of line-leading spaces
|
|
/// </summary>
|
|
private string Outdent(string block)
|
|
{
|
|
return _outDent.Replace(block, "");
|
|
}
|
|
|
|
#region Encoding and Normalization
|
|
|
|
/// <summary>
|
|
/// encodes email address randomly
|
|
/// roughly 10% raw, 45% hex, 45% dec
|
|
/// note that @ is always encoded and : never is
|
|
/// </summary>
|
|
private string EncodeEmailAddress(string addr)
|
|
{
|
|
var sb = new StringBuilder(addr.Length * 5);
|
|
var rand = new Random();
|
|
int r;
|
|
foreach (char c in addr)
|
|
{
|
|
r = rand.Next(1, 100);
|
|
if ((r > 90 || c == ':') && c != '@')
|
|
sb.Append(c); // m
|
|
else if (r < 45)
|
|
sb.AppendFormat("&#x{0:x};", (int)c); // m
|
|
else
|
|
sb.AppendFormat("&#{0};", (int)c); // m
|
|
}
|
|
return sb.ToString();
|
|
}
|
|
|
|
private static readonly Regex _codeEncoder = new Regex(@"&|<|>|\\|\*|_|\{|\}|\[|\]", RegexOptions.Compiled);
|
|
|
|
/// <summary>
|
|
/// Encode/escape certain Markdown characters inside code blocks and spans where they are literals
|
|
/// </summary>
|
|
private string EncodeCode(string code)
|
|
{
|
|
return _codeEncoder.Replace(code, EncodeCodeEvaluator);
|
|
}
|
|
|
|
private string EncodeCodeEvaluator(Match match)
|
|
{
|
|
switch (match.Value)
|
|
{
|
|
// Encode all ampersands; HTML entities are not
|
|
// entities within a Markdown code span.
|
|
case "&":
|
|
return "&";
|
|
// Do the angle bracket song and dance
|
|
case "<":
|
|
return "<";
|
|
case ">":
|
|
return ">";
|
|
// escape characters that are magic in Markdown
|
|
default:
|
|
return _escapeTable[match.Value];
|
|
}
|
|
}
|
|
|
|
private static readonly Regex _amps = new Regex("&(?!((#[0-9]+)|(#[xX][a-fA-F0-9]+)|([a-zA-Z][a-zA-Z0-9]*));)", RegexOptions.ExplicitCapture | RegexOptions.Compiled);
|
|
private static readonly Regex _angles = new Regex(@"<(?![A-Za-z/?\$!])", RegexOptions.ExplicitCapture | RegexOptions.Compiled);
|
|
|
|
/// <summary>
|
|
/// Encode any ampersands (that aren't part of an HTML entity) and left or right angle brackets
|
|
/// </summary>
|
|
private string EncodeAmpsAndAngles(string s)
|
|
{
|
|
s = _amps.Replace(s, "&");
|
|
return _angles.Replace(s, "<");
|
|
}
|
|
|
|
private static readonly Regex _backslashEscapes;
|
|
|
|
/// <summary>
|
|
/// Encodes any escaped characters such as \`, \*, \[ etc
|
|
/// </summary>
|
|
private string EscapeBackslashes(string s) => _backslashEscapes.Replace(s, new MatchEvaluator(EscapeBackslashesEvaluator));
|
|
|
|
private string EscapeBackslashesEvaluator(Match match) => _backslashEscapeTable[match.Value];
|
|
|
|
// note: this space MATTERS - do not remove (hex / unicode) \|/
|
|
#pragma warning disable RCS1190 // Join string expressions.
|
|
private static readonly Regex _unescapes = new Regex("\x1A" + "E\\d+E", RegexOptions.Compiled);
|
|
#pragma warning restore RCS1190 // Join string expressions.
|
|
|
|
/// <summary>
|
|
/// swap back in all the special characters we've hidden
|
|
/// </summary>
|
|
private string Unescape(string s) => _unescapes.Replace(s, new MatchEvaluator(UnescapeEvaluator));
|
|
|
|
private string UnescapeEvaluator(Match match) => _invertedEscapeTable[match.Value];
|
|
|
|
/// <summary>
|
|
/// escapes Bold [ * ] and Italic [ _ ] characters
|
|
/// </summary>
|
|
private string EscapeBoldItalic(string s)
|
|
{
|
|
s = s.Replace("*", _escapeTable["*"]);
|
|
return s.Replace("_", _escapeTable["_"]);
|
|
}
|
|
|
|
private static string AttributeEncode(string s)
|
|
{
|
|
return s.Replace(">", ">").Replace("<", "<").Replace("\"", """).Replace("'", "'");
|
|
}
|
|
|
|
private static string AttributeSafeUrl(string s)
|
|
{
|
|
s = AttributeEncode(s);
|
|
foreach (var c in "*_:()[]")
|
|
s = s.Replace(c.ToString(), _escapeTable[c.ToString()]);
|
|
return s;
|
|
}
|
|
|
|
/// <summary>
|
|
/// Within tags -- meaning between < and > -- encode [\ ` * _] so they
|
|
/// don't conflict with their use in Markdown for code, italics and strong.
|
|
/// We're replacing each such character with its corresponding hash
|
|
/// value; this is likely overkill, but it should prevent us from colliding
|
|
/// with the escape values by accident.
|
|
/// </summary>
|
|
private string EscapeSpecialCharsWithinTagAttributes(string text)
|
|
{
|
|
var tokens = TokenizeHTML(text);
|
|
|
|
// now, rebuild text from the tokens
|
|
var sb = new StringBuilder(text.Length);
|
|
|
|
foreach (var token in tokens)
|
|
{
|
|
string value = token.Value;
|
|
|
|
if (token.Type == TokenType.Tag)
|
|
{
|
|
value = value.Replace(@"\", _escapeTable[@"\"]);
|
|
|
|
if (AutoHyperlink && value.StartsWith("<!")) // escape slashes in comments to prevent autolinking there -- https://meta.stackexchange.com/questions/95987/html-comment-containing-url-breaks-if-followed-by-another-html-comment
|
|
value = value.Replace("/", _escapeTable["/"]);
|
|
|
|
value = Regex.Replace(value, "(?<=.)</?code>(?=.)", _escapeTable["`"]);
|
|
value = EscapeBoldItalic(value);
|
|
}
|
|
|
|
sb.Append(value);
|
|
}
|
|
|
|
return sb.ToString();
|
|
}
|
|
|
|
/// <summary>
|
|
/// convert all tabs to _tabWidth spaces;
|
|
/// standardizes line endings from DOS (CR LF) or Mac (CR) to UNIX (LF);
|
|
/// makes sure text ends with a couple of newlines;
|
|
/// removes any blank lines (only spaces) in the text
|
|
/// </summary>
|
|
private string Normalize(string text)
|
|
{
|
|
var output = new StringBuilder(text.Length);
|
|
var line = new StringBuilder();
|
|
bool valid = false;
|
|
|
|
for (int i = 0; i < text.Length; i++)
|
|
{
|
|
switch (text[i])
|
|
{
|
|
case '\n':
|
|
if (valid) output.Append(line);
|
|
output.Append('\n');
|
|
line.Length = 0; valid = false;
|
|
break;
|
|
case '\r':
|
|
if ((i < text.Length - 1) && (text[i + 1] != '\n'))
|
|
{
|
|
if (valid) output.Append(line);
|
|
output.Append('\n');
|
|
line.Length = 0; valid = false;
|
|
}
|
|
break;
|
|
case '\t':
|
|
int width = (_tabWidth - (line.Length % _tabWidth));
|
|
for (int k = 0; k < width; k++)
|
|
line.Append(' ');
|
|
break;
|
|
case '\x1A':
|
|
break;
|
|
default:
|
|
if (!valid && text[i] != ' ') valid = true;
|
|
line.Append(text[i]);
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (valid) output.Append(line);
|
|
output.Append('\n');
|
|
|
|
// add two newlines to the end before return
|
|
return output.Append("\n\n").ToString();
|
|
}
|
|
|
|
#endregion
|
|
|
|
/// <summary>
|
|
/// this is to emulate what's evailable in PHP
|
|
/// </summary>
|
|
private static string RepeatString(string text, int count)
|
|
{
|
|
var sb = new StringBuilder(text.Length * count);
|
|
for (int i = 0; i < count; i++)
|
|
sb.Append(text);
|
|
return sb.ToString();
|
|
}
|
|
}
|
|
|
|
}
|