source: trunk/HeuristicLab.ExtLibs/HeuristicLab.AvalonEdit/5.0.1/AvalonEdit-5.0.1/Rendering/LinkElementGenerator.cs

// Copyright (c) 2014 AlphaSierraPapa for the SharpDevelop Team
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy of this
// software and associated documentation files (the "Software"), to deal in the Software
// without restriction, including without limitation the rights to use, copy, modify, merge,
// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
// to whom the Software is furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in all copies or
// substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.

using System;
using System.Text.RegularExpressions;
using ICSharpCode.AvalonEdit.Utils;

namespace ICSharpCode.AvalonEdit.Rendering
{
  // This class is public because it can be used as a base class for custom links.
  
  /// <summary>
  /// Detects hyperlinks and makes them clickable.
  /// </summary>
  /// <remarks>
  /// This element generator can be easily enabled and configured using the
  /// <see cref="TextEditorOptions"/>.
  /// </remarks>
  public class LinkElementGenerator : VisualLineElementGenerator, IBuiltinElementGenerator
  {
    // a link starts with a protocol (or just with www), followed by 0 or more 'link characters', followed by a link end character
    // (this allows accepting punctuation inside links but not at the end)
    internal readonly static Regex defaultLinkRegex = new Regex(@"\b(https?://|ftp://|www\.)[\w\d\._/\-~%@()+:?&=#!]*[\w\d/]");
    
    // try to detect email addresses
    internal readonly static Regex defaultMailRegex = new Regex(@"\b[\w\d\.\-]+\@[\w\d\.\-]+\.[a-z]{2,6}\b");
    
    readonly Regex linkRegex;
    
    /// <summary>
    /// Gets/Sets whether the user needs to press Control to click the link.
    /// The default value is true.
    /// </summary>
    public bool RequireControlModifierForClick { get; set; }
    
    /// <summary>
    /// Creates a new LinkElementGenerator.
    /// </summary>
    public LinkElementGenerator()
    {
      this.linkRegex = defaultLinkRegex;
      this.RequireControlModifierForClick = true;
    }
    
    /// <summary>
    /// Creates a new LinkElementGenerator using the specified regex.
    /// </summary>
    protected LinkElementGenerator(Regex regex) : this()
    {
      if (regex == null)
        throw new ArgumentNullException("regex");
      this.linkRegex = regex;
    }
    
    void IBuiltinElementGenerator.FetchOptions(TextEditorOptions options)
    {
      this.RequireControlModifierForClick = options.RequireControlModifierForHyperlinkClick;
    }
    
    Match GetMatch(int startOffset, out int matchOffset)
    {
      int endOffset = CurrentContext.VisualLine.LastDocumentLine.EndOffset;
      StringSegment relevantText = CurrentContext.GetText(startOffset, endOffset - startOffset);
      Match m = linkRegex.Match(relevantText.Text, relevantText.Offset, relevantText.Count);
      matchOffset = m.Success ? m.Index - relevantText.Offset + startOffset : -1;
      return m;
    }
    
    /// <inheritdoc/>
    public override int GetFirstInterestedOffset(int startOffset)
    {
      int matchOffset;
      GetMatch(startOffset, out matchOffset);
      return matchOffset;
    }
    
    /// <inheritdoc/>
    public override VisualLineElement ConstructElement(int offset)
    {
      int matchOffset;
      Match m = GetMatch(offset, out matchOffset);
      if (m.Success && matchOffset == offset) {
        return ConstructElementFromMatch(m);
      } else {
        return null;
      }
    }
    
    /// <summary>
    /// Constructs a VisualLineElement that replaces the matched text.
    /// The default implementation will create a <see cref="VisualLineLinkText"/>
    /// based on the URI provided by <see cref="GetUriFromMatch"/>.
    /// </summary>
    protected virtual VisualLineElement ConstructElementFromMatch(Match m)
    {
      Uri uri = GetUriFromMatch(m);
      if (uri == null)
        return null;
      VisualLineLinkText linkText = new VisualLineLinkText(CurrentContext.VisualLine, m.Length);
      linkText.NavigateUri = uri;
      linkText.RequireControlModifierForClick = this.RequireControlModifierForClick;
      return linkText;
    }
    
    /// <summary>
    /// Fetches the URI from the regex match. Returns null if the URI format is invalid.
    /// </summary>
    protected virtual Uri GetUriFromMatch(Match match)
    {
      string targetUrl = match.Value;
      if (targetUrl.StartsWith("www.", StringComparison.Ordinal))
        targetUrl = "http://" + targetUrl;
      if (Uri.IsWellFormedUriString(targetUrl, UriKind.Absolute))
        return new Uri(targetUrl);
      
      return null;
    }
  }
  
  // This class is internal because it does not need to be accessed by the user - it can be configured using TextEditorOptions.
  
  /// <summary>
  /// Detects e-mail addresses and makes them clickable.
  /// </summary>
  /// <remarks>
  /// This element generator can be easily enabled and configured using the
  /// <see cref="TextEditorOptions"/>.
  /// </remarks>
  sealed class MailLinkElementGenerator : LinkElementGenerator
  {
    /// <summary>
    /// Creates a new MailLinkElementGenerator.
    /// </summary>
    public MailLinkElementGenerator()
      : base(defaultMailRegex)
    {
    }
    
    protected override Uri GetUriFromMatch(Match match)
    {
      return new Uri("mailto:" + match.Value);
    }
  }
}