source: trunk/HeuristicLab.ExtLibs/HeuristicLab.AvalonEdit/5.0.1/AvalonEdit-5.0.1/Editing/TextSegmentReadOnlySectionProvider.cs @ 17495

// 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
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// DEALINGS IN THE SOFTWARE.

using System;
using System.Collections.Generic;
using ICSharpCode.AvalonEdit.Document;
#if NREFACTORY
using ICSharpCode.NRefactory.Editor;
#endif

namespace ICSharpCode.AvalonEdit.Editing
{
  /// <summary>
  /// Implementation for <see cref="IReadOnlySectionProvider"/> that stores the segments
  /// in a <see cref="TextSegmentCollection{T}"/>.
  /// </summary>
  public class TextSegmentReadOnlySectionProvider<T> : IReadOnlySectionProvider where T : TextSegment
  {
    readonly TextSegmentCollection<T> segments;
    
    /// <summary>
    /// Gets the collection storing the read-only segments.
    /// </summary>
    public TextSegmentCollection<T> Segments {
      get { return segments; }
    }
    
    /// <summary>
    /// Creates a new TextSegmentReadOnlySectionProvider instance for the specified document.
    /// </summary>
    public TextSegmentReadOnlySectionProvider(TextDocument textDocument)
    {
      segments = new TextSegmentCollection<T>(textDocument);
    }
    
    /// <summary>
    /// Creates a new TextSegmentReadOnlySectionProvider instance using the specified TextSegmentCollection.
    /// </summary>
    public TextSegmentReadOnlySectionProvider(TextSegmentCollection<T> segments)
    {
      if (segments == null)
        throw new ArgumentNullException("segments");
      this.segments = segments;
    }
    
    /// <summary>
    /// Gets whether insertion is possible at the specified offset.
    /// </summary>
    public virtual bool CanInsert(int offset)
    {
      foreach (TextSegment segment in segments.FindSegmentsContaining(offset)) {
        if (segment.StartOffset < offset && offset < segment.EndOffset)
          return false;
      }
      return true;
    }
    
    /// <summary>
    /// Gets the deletable segments inside the given segment.
    /// </summary>
    public virtual IEnumerable<ISegment> GetDeletableSegments(ISegment segment)
    {
      if (segment == null)
        throw new ArgumentNullException("segment");
      
      if (segment.Length == 0 && CanInsert(segment.Offset)) {
        yield return segment;
        yield break;
      }
      
      int readonlyUntil = segment.Offset;
      foreach (TextSegment ts in segments.FindOverlappingSegments(segment)) {
        int start = ts.StartOffset;
        int end = start + ts.Length;
        if (start > readonlyUntil) {
          yield return new SimpleSegment(readonlyUntil, start - readonlyUntil);
        }
        if (end > readonlyUntil) {
          readonlyUntil = end;
        }
      }
      int endOffset = segment.EndOffset;
      if (readonlyUntil < endOffset) {
        yield return new SimpleSegment(readonlyUntil, endOffset - readonlyUntil);
      }
    }
  }
}