// 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;
namespace Unity.CodeEditor.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>
internal 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.
private readonly TextDocument _document;
#endif
private bool _isDeleted;
internal DocumentLine(TextDocument document)
{
#if DEBUG
Debug.Assert(document != null);
_document = document;
#endif
}
[Conditional("DEBUG")]
private 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;
}
set => _isDeleted = value;
}
/// <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 => Offset + Length;
#endregion
#region Length
private int _totalLength;
private 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;
}
// this is set by DocumentLineTree
set => _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;
}
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;
}
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;
}
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 => NextLine;
IDocumentLine IDocumentLine.PreviousLine => 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]";
return string.Format(
CultureInfo.InvariantCulture,
"[DocumentLine Number={0} Offset={1} Length={2}]", LineNumber, Offset, Length);
}
#endregion
}
}