source: stable/HeuristicLab.ExtLibs/HeuristicLab.AvalonEdit/5.0.1/AvalonEdit-5.0.1/Indentation/DefaultIndentationStrategy.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 ICSharpCode.NRefactory.Editor;
using ICSharpCode.AvalonEdit.Document;

namespace ICSharpCode.AvalonEdit.Indentation
{
  /// <summary>
  /// Handles indentation by copying the indentation from the previous line.
  /// Does not support indenting multiple lines.
  /// </summary>
  public class DefaultIndentationStrategy : IIndentationStrategy
  {
    /// <inheritdoc/>
    public virtual void IndentLine(TextDocument document, DocumentLine line)
    {
      if (document == null)
        throw new ArgumentNullException("document");
      if (line == null)
        throw new ArgumentNullException("line");
      DocumentLine previousLine = line.PreviousLine;
      if (previousLine != null) {
        ISegment indentationSegment = TextUtilities.GetWhitespaceAfter(document, previousLine.Offset);
        string indentation = document.GetText(indentationSegment);
        // copy indentation to line
        indentationSegment = TextUtilities.GetWhitespaceAfter(document, line.Offset);
        document.Replace(indentationSegment, indentation);
      }
    }
    
    /// <summary>
    /// Does nothing: indenting multiple lines is useless without a smart indentation strategy.
    /// </summary>
    public virtual void IndentLines(TextDocument document, int beginLine, int endLine)
    {
    }
  }
}