source: branches/2929_PrioritizedGrammarEnumeration/HeuristicLab.ExtLibs/HeuristicLab.AvalonEdit/5.0.1/AvalonEdit-5.0.1/Snippets/SnippetBoundElement.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.Windows.Documents;
using ICSharpCode.AvalonEdit.Document;
using ICSharpCode.NRefactory.Editor;

namespace ICSharpCode.AvalonEdit.Snippets
{
  /// <summary>
  /// An element that binds to a <see cref="SnippetReplaceableTextElement"/> and displays the same text.
  /// </summary>
  [Serializable]
  public class SnippetBoundElement : SnippetElement
  {
    SnippetReplaceableTextElement targetElement;
    
    /// <summary>
    /// Gets/Sets the target element.
    /// </summary>
    public SnippetReplaceableTextElement TargetElement {
      get { return targetElement; }
      set { targetElement = value; }
    }
    
    /// <summary>
    /// Converts the text before copying it.
    /// </summary>
    public virtual string ConvertText(string input)
    {
      return input;
    }
    
    /// <inheritdoc/>
    public override void Insert(InsertionContext context)
    {
      if (targetElement != null) {
        TextAnchor start = context.Document.CreateAnchor(context.InsertionPosition);
        start.MovementType = AnchorMovementType.BeforeInsertion;
        start.SurviveDeletion = true;
        string inputText = targetElement.Text;
        if (inputText != null) {
          context.InsertText(ConvertText(inputText));
        }
        TextAnchor end = context.Document.CreateAnchor(context.InsertionPosition);
        end.MovementType = AnchorMovementType.BeforeInsertion;
        end.SurviveDeletion = true;
        AnchorSegment segment = new AnchorSegment(start, end);
        context.RegisterActiveElement(this, new BoundActiveElement(context, targetElement, this, segment));
      }
    }
    
    /// <inheritdoc/>
    public override Inline ToTextRun()
    {
      if (targetElement != null) {
        string inputText = targetElement.Text;
        if (inputText != null) {
          return new Italic(new Run(ConvertText(inputText)));
        }
      }
      return base.ToTextRun();
    }
  }
  
  sealed class BoundActiveElement : IActiveElement
  {
    InsertionContext context;
    SnippetReplaceableTextElement targetSnippetElement;
    SnippetBoundElement boundElement;
    internal IReplaceableActiveElement targetElement;
    AnchorSegment segment;
    
    public BoundActiveElement(InsertionContext context, SnippetReplaceableTextElement targetSnippetElement, SnippetBoundElement boundElement, AnchorSegment segment)
    {
      this.context = context;
      this.targetSnippetElement = targetSnippetElement;
      this.boundElement = boundElement;
      this.segment = segment;
    }
    
    public void OnInsertionCompleted()
    {
      targetElement = context.GetActiveElement(targetSnippetElement) as IReplaceableActiveElement;
      if (targetElement != null) {
        targetElement.TextChanged += targetElement_TextChanged;
      }
    }
    
    void targetElement_TextChanged(object sender, EventArgs e)
    {
      // Don't copy text if the segments overlap (we would get an endless loop).
      // This can happen if the user deletes the text between the replaceable element and the bound element.
      if (SimpleSegment.GetOverlap(segment, targetElement.Segment) == SimpleSegment.Invalid) {
        int offset = segment.Offset;
        int length = segment.Length;
        string text = boundElement.ConvertText(targetElement.Text);
        if (length != text.Length || text != context.Document.GetText(offset, length)) {
          // Call replace only if we're actually changing something.
          // Without this check, we would generate an empty undo group when the user pressed undo.
          context.Document.Replace(offset, length, text);
          if (length == 0) {
            // replacing an empty anchor segment with text won't enlarge it, so we have to recreate it
            segment = new AnchorSegment(context.Document, offset, text.Length);
          }
        }
      }
    }
    
    public void Deactivate(SnippetEventArgs e)
    {
    }
    
    public bool IsEditable {
      get { return false; }
    }
    
    public ISegment Segment {
      get { return segment; }
    }
  }
}