source: trunk/HeuristicLab.ExtLibs/HeuristicLab.AvalonEdit/5.0.1/AvalonEdit-5.0.1/Document/DocumentLine.cs @ 16014

// 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.Diagnostics;
using System.Globalization;
#if NREFACTORY
using ICSharpCode.NRefactory.Editor;
#endif

namespace ICSharpCode.AvalonEdit.Document
{
  /// <summary>
  /// Represents a line inside a <see cref="TextDocument"/>.
  /// </summary>
  /// <remarks>
  /// <para>
  /// The <see cref="TextDocument.Lines"/> collection contains one DocumentLine instance
  /// for every line in the document. This collection is read-only to user code and is automatically
  /// updated to reflect the current document content.
  /// </para>
  /// <para>
  /// Internally, the DocumentLine instances are arranged in a binary tree that allows for both efficient updates and lookup.
  /// Converting between offset and line number is possible in O(lg N) time,
  /// and the data structure also updates all offsets in O(lg N) whenever a line is inserted or removed.
  /// </para>
  /// </remarks>
  public sealed partial class DocumentLine : IDocumentLine
  {
    #region Constructor
    #if DEBUG
    // Required for thread safety check which is done only in debug builds.
    // To save space, we don't store the document reference in release builds as we don't need it there.
    readonly TextDocument document;
    #endif
    
    internal bool isDeleted;
    
    internal DocumentLine(TextDocument document)
    {
      #if DEBUG
      Debug.Assert(document != null);
      this.document = document;
      #endif
    }
    
    [Conditional("DEBUG")]
    void DebugVerifyAccess()
    {
      #if DEBUG
      document.DebugVerifyAccess();
      #endif
    }
    #endregion
    
    #region Events
//    /// <summary>
//    /// Is raised when the line is deleted.
//    /// </summary>
//    public event EventHandler Deleted;
//
//    /// <summary>
//    /// Is raised when the line's text changes.
//    /// </summary>
//    public event EventHandler TextChanged;
//
//    /// <summary>
//    /// Raises the Deleted or TextChanged event.
//    /// </summary>
//    internal void RaiseChanged()
//    {
//      if (IsDeleted) {
//        if (Deleted != null)
//          Deleted(this, EventArgs.Empty);
//      } else {
//        if (TextChanged != null)
//          TextChanged(this, EventArgs.Empty);
//      }
//    }
    #endregion
    
    #region Properties stored in tree
    /// <summary>
    /// Gets if this line was deleted from the document.
    /// </summary>
    public bool IsDeleted {
      get {
        DebugVerifyAccess();
        return isDeleted;
      }
    }
    
    /// <summary>
    /// Gets the number of this line.
    /// Runtime: O(log n)
    /// </summary>
    /// <exception cref="InvalidOperationException">The line was deleted.</exception>
    public int LineNumber {
      get {
        if (IsDeleted)
          throw new InvalidOperationException();
        return DocumentLineTree.GetIndexFromNode(this) + 1;
      }
    }
    
    /// <summary>
    /// Gets the starting offset of the line in the document's text.
    /// Runtime: O(log n)
    /// </summary>
    /// <exception cref="InvalidOperationException">The line was deleted.</exception>
    public int Offset {
      get {
        if (IsDeleted)
          throw new InvalidOperationException();
        return DocumentLineTree.GetOffsetFromNode(this);
      }
    }
    
    /// <summary>
    /// Gets the end offset of the line in the document's text (the offset before the line delimiter).
    /// Runtime: O(log n)
    /// </summary>
    /// <exception cref="InvalidOperationException">The line was deleted.</exception>
    /// <remarks>EndOffset = <see cref="Offset"/> + <see cref="Length"/>.</remarks>
    public int EndOffset {
      get { return this.Offset + this.Length; }
    }
    #endregion
    
    #region Length
    int totalLength;
    byte delimiterLength;
    
    /// <summary>
    /// Gets the length of this line. The length does not include the line delimiter. O(1)
    /// </summary>
    /// <remarks>This property is still available even if the line was deleted;
    /// in that case, it contains the line's length before the deletion.</remarks>
    public int Length {
      get {
        DebugVerifyAccess();
        return totalLength - delimiterLength;
      }
    }
    
    /// <summary>
    /// Gets the length of this line, including the line delimiter. O(1)
    /// </summary>
    /// <remarks>This property is still available even if the line was deleted;
    /// in that case, it contains the line's length before the deletion.</remarks>
    public int TotalLength {
      get {
        DebugVerifyAccess();
        return totalLength;
      }
      internal set {
        // this is set by DocumentLineTree
        totalLength = value;
      }
    }
    
    /// <summary>
    /// <para>Gets the length of the line delimiter.</para>
    /// <para>The value is 1 for single <c>"\r"</c> or <c>"\n"</c>, 2 for the <c>"\r\n"</c> sequence;
    /// and 0 for the last line in the document.</para>
    /// </summary>
    /// <remarks>This property is still available even if the line was deleted;
    /// in that case, it contains the line delimiter's length before the deletion.</remarks>
    public int DelimiterLength {
      get {
        DebugVerifyAccess();
        return delimiterLength;
      }
      internal set {
        Debug.Assert(value >= 0 && value <= 2);
        delimiterLength = (byte)value;
      }
    }
    #endregion
    
    #region Previous / Next Line
    /// <summary>
    /// Gets the next line in the document.
    /// </summary>
    /// <returns>The line following this line, or null if this is the last line.</returns>
    public DocumentLine NextLine {
      get {
        DebugVerifyAccess();
        
        if (right != null) {
          return right.LeftMost;
        } else {
          DocumentLine node = this;
          DocumentLine oldNode;
          do {
            oldNode = node;
            node = node.parent;
            // we are on the way up from the right part, don't output node again
          } while (node != null && node.right == oldNode);
          return node;
        }
      }
    }
    
    /// <summary>
    /// Gets the previous line in the document.
    /// </summary>
    /// <returns>The line before this line, or null if this is the first line.</returns>
    public DocumentLine PreviousLine {
      get {
        DebugVerifyAccess();
        
        if (left != null) {
          return left.RightMost;
        } else {
          DocumentLine node = this;
          DocumentLine oldNode;
          do {
            oldNode = node;
            node = node.parent;
            // we are on the way up from the left part, don't output node again
          } while (node != null && node.left == oldNode);
          return node;
        }
      }
    }
    
    IDocumentLine IDocumentLine.NextLine {
      get { return this.NextLine; }
    }
    
    IDocumentLine IDocumentLine.PreviousLine {
      get { return this.PreviousLine; }
    }
    #endregion
    
    #region ToString
    /// <summary>
    /// Gets a string with debug output showing the line number and offset.
    /// Does not include the line's text.
    /// </summary>
    public override string ToString()
    {
      if (IsDeleted)
        return "[DocumentLine deleted]";
      else
        return string.Format(
          CultureInfo.InvariantCulture,
          "[DocumentLine Number={0} Offset={1} Length={2}]", LineNumber, Offset, Length);
    }
    #endregion
  }
}