source: trunk/HeuristicLab.ExtLibs/HeuristicLab.NRefactory/5.5.0/NRefactory-5.5.0/Editor/TextChangeEventArgs.cs

// Copyright (c) 2010-2013 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
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// DEALINGS IN THE SOFTWARE.

using System;

namespace ICSharpCode.NRefactory.Editor
{
  /// <summary>
  /// Describes a change of the document text.
  /// This class is thread-safe.
  /// </summary>
  [Serializable]
  public class TextChangeEventArgs : EventArgs
  {
    readonly int offset;
    readonly ITextSource removedText;
    readonly ITextSource insertedText;
    
    /// <summary>
    /// The offset at which the change occurs.
    /// </summary>
    public int Offset {
      get { return offset; }
    }
    
    /// <summary>
    /// The text that was removed.
    /// </summary>
    public ITextSource RemovedText {
      get { return removedText; }
    }
    
    /// <summary>
    /// The number of characters removed.
    /// </summary>
    public int RemovalLength {
      get { return removedText.TextLength; }
    }
    
    /// <summary>
    /// The text that was inserted.
    /// </summary>
    public ITextSource InsertedText {
      get { return insertedText; }
    }
    
    /// <summary>
    /// The number of characters inserted.
    /// </summary>
    public int InsertionLength {
      get { return insertedText.TextLength; }
    }
    
    /// <summary>
    /// Creates a new TextChangeEventArgs object.
    /// </summary>
    public TextChangeEventArgs(int offset, string removedText, string insertedText)
    {
      if (offset < 0)
        throw new ArgumentOutOfRangeException("offset", offset, "offset must not be negative");
      this.offset = offset;
      this.removedText = removedText != null ? new StringTextSource(removedText) : StringTextSource.Empty;
      this.insertedText = insertedText != null ? new StringTextSource(insertedText) : StringTextSource.Empty;
    }
    
    /// <summary>
    /// Creates a new TextChangeEventArgs object.
    /// </summary>
    public TextChangeEventArgs(int offset, ITextSource removedText, ITextSource insertedText)
    {
      if (offset < 0)
        throw new ArgumentOutOfRangeException("offset", offset, "offset must not be negative");
      this.offset = offset;
      this.removedText = removedText ?? StringTextSource.Empty;
      this.insertedText = insertedText ?? StringTextSource.Empty;
    }
    
    /// <summary>
    /// Gets the new offset where the specified offset moves after this document change.
    /// </summary>
    public virtual int GetNewOffset(int offset, AnchorMovementType movementType = AnchorMovementType.Default)
    {
      if (offset >= this.Offset && offset <= this.Offset + this.RemovalLength) {
        if (movementType == AnchorMovementType.BeforeInsertion)
          return this.Offset;
        else
          return this.Offset + this.InsertionLength;
      } else if (offset > this.Offset) {
        return offset + this.InsertionLength - this.RemovalLength;
      } else {
        return offset;
      }
    }
    
    /// <summary>
    /// Creates TextChangeEventArgs for the reverse change.
    /// </summary>
    public virtual TextChangeEventArgs Invert()
    {
      return new TextChangeEventArgs(offset, insertedText, removedText);
    }
  }
}