source: branches/PersistenceOverhaul/HeuristicLab.ExtLibs/HeuristicLab.AvalonEdit/5.0.1/AvalonEdit-5.0.1/Editing/Selection.cs @ 18242

// 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.Collections.Generic;
using System.Text;
using System.Windows;

using ICSharpCode.AvalonEdit.Document;
using ICSharpCode.AvalonEdit.Highlighting;
using ICSharpCode.AvalonEdit.Utils;
#if NREFACTORY
using ICSharpCode.NRefactory.Editor;
#endif

namespace ICSharpCode.AvalonEdit.Editing
{
  /// <summary>
  /// Base class for selections.
  /// </summary>
  public abstract class Selection
  {
    /// <summary>
    /// Creates a new simple selection that selects the text from startOffset to endOffset.
    /// </summary>
    public static Selection Create(TextArea textArea, int startOffset, int endOffset)
    {
      if (textArea == null)
        throw new ArgumentNullException("textArea");
      if (startOffset == endOffset)
        return textArea.emptySelection;
      else
        return new SimpleSelection(textArea,
                                   new TextViewPosition(textArea.Document.GetLocation(startOffset)),
                                   new TextViewPosition(textArea.Document.GetLocation(endOffset)));
    }
    
    internal static Selection Create(TextArea textArea, TextViewPosition start, TextViewPosition end)
    {
      if (textArea == null)
        throw new ArgumentNullException("textArea");
      if (textArea.Document.GetOffset(start.Location) == textArea.Document.GetOffset(end.Location) && start.VisualColumn == end.VisualColumn)
        return textArea.emptySelection;
      else
        return new SimpleSelection(textArea, start, end);
    }
    
    /// <summary>
    /// Creates a new simple selection that selects the text in the specified segment.
    /// </summary>
    public static Selection Create(TextArea textArea, ISegment segment)
    {
      if (segment == null)
        throw new ArgumentNullException("segment");
      return Create(textArea, segment.Offset, segment.EndOffset);
    }
    
    internal readonly TextArea textArea;
    
    /// <summary>
    /// Constructor for Selection.
    /// </summary>
    protected Selection(TextArea textArea)
    {
      if (textArea == null)
        throw new ArgumentNullException("textArea");
      this.textArea = textArea;
    }
    
    /// <summary>
    /// Gets the start position of the selection.
    /// </summary>
    public abstract TextViewPosition StartPosition { get; }
    
    /// <summary>
    /// Gets the end position of the selection.
    /// </summary>
    public abstract TextViewPosition EndPosition { get; }
    
    /// <summary>
    /// Gets the selected text segments.
    /// </summary>
    public abstract IEnumerable<SelectionSegment> Segments { get; }
    
    /// <summary>
    /// Gets the smallest segment that contains all segments in this selection.
    /// May return null if the selection is empty.
    /// </summary>
    public abstract ISegment SurroundingSegment { get; }
    
    /// <summary>
    /// Replaces the selection with the specified text.
    /// </summary>
    public abstract void ReplaceSelectionWithText(string newText);
    
    internal string AddSpacesIfRequired(string newText, TextViewPosition start, TextViewPosition end)
    {
      if (EnableVirtualSpace && InsertVirtualSpaces(newText, start, end)) {
        var line = textArea.Document.GetLineByNumber(start.Line);
        string lineText = textArea.Document.GetText(line);
        var vLine = textArea.TextView.GetOrConstructVisualLine(line);
        int colDiff = start.VisualColumn - vLine.VisualLengthWithEndOfLineMarker;
        if (colDiff > 0) {
          string additionalSpaces = "";
          if (!textArea.Options.ConvertTabsToSpaces && lineText.Trim('\t').Length == 0) {
            int tabCount = (int)(colDiff / textArea.Options.IndentationSize);
            additionalSpaces = new string('\t', tabCount);
            colDiff -= tabCount * textArea.Options.IndentationSize;
          }
          additionalSpaces += new string(' ', colDiff);
          return additionalSpaces + newText;
        }
      }
      return newText;
    }
    
    bool InsertVirtualSpaces(string newText, TextViewPosition start, TextViewPosition end)
    {
      return (!string.IsNullOrEmpty(newText) || !(IsInVirtualSpace(start) && IsInVirtualSpace(end)))
        && newText != "\r\n"
        && newText != "\n"
        && newText != "\r";
    }
    
    bool IsInVirtualSpace(TextViewPosition pos)
    {
      return pos.VisualColumn > textArea.TextView.GetOrConstructVisualLine(textArea.Document.GetLineByNumber(pos.Line)).VisualLength;
    }
    
    /// <summary>
    /// Updates the selection when the document changes.
    /// </summary>
    public abstract Selection UpdateOnDocumentChange(DocumentChangeEventArgs e);
    
    /// <summary>
    /// Gets whether the selection is empty.
    /// </summary>
    public virtual bool IsEmpty {
      get { return Length == 0; }
    }
    
    /// <summary>
    /// Gets whether virtual space is enabled for this selection.
    /// </summary>
    public virtual bool EnableVirtualSpace {
      get { return textArea.Options.EnableVirtualSpace; }
    }
    
    /// <summary>
    /// Gets the selection length.
    /// </summary>
    public abstract int Length { get; }
    
    /// <summary>
    /// Returns a new selection with the changed end point.
    /// </summary>
    /// <exception cref="NotSupportedException">Cannot set endpoint for empty selection</exception>
    public abstract Selection SetEndpoint(TextViewPosition endPosition);
    
    /// <summary>
    /// If this selection is empty, starts a new selection from <paramref name="startPosition"/> to
    /// <paramref name="endPosition"/>, otherwise, changes the endpoint of this selection.
    /// </summary>
    public abstract Selection StartSelectionOrSetEndpoint(TextViewPosition startPosition, TextViewPosition endPosition);
    
    /// <summary>
    /// Gets whether the selection is multi-line.
    /// </summary>
    public virtual bool IsMultiline {
      get {
        ISegment surroundingSegment = this.SurroundingSegment;
        if (surroundingSegment == null)
          return false;
        int start = surroundingSegment.Offset;
        int end = start + surroundingSegment.Length;
        var document = textArea.Document;
        if (document == null)
          throw ThrowUtil.NoDocumentAssigned();
        return document.GetLineByOffset(start) != document.GetLineByOffset(end);
      }
    }
    
    /// <summary>
    /// Gets the selected text.
    /// </summary>
    public virtual string GetText()
    {
      var document = textArea.Document;
      if (document == null)
        throw ThrowUtil.NoDocumentAssigned();
      StringBuilder b = null;
      string text = null;
      foreach (ISegment s in Segments) {
        if (text != null) {
          if (b == null)
            b = new StringBuilder(text);
          else
            b.Append(text);
        }
        text = document.GetText(s);
      }
      if (b != null) {
        if (text != null) b.Append(text);
        return b.ToString();
      } else {
        return text ?? string.Empty;
      }
    }
    
    /// <summary>
    /// Creates a HTML fragment for the selected text.
    /// </summary>
    public string CreateHtmlFragment(HtmlOptions options)
    {
      if (options == null)
        throw new ArgumentNullException("options");
      IHighlighter highlighter = textArea.GetService(typeof(IHighlighter)) as IHighlighter;
      StringBuilder html = new StringBuilder();
      bool first = true;
      foreach (ISegment selectedSegment in this.Segments) {
        if (first)
          first = false;
        else
          html.AppendLine("<br>");
        html.Append(HtmlClipboard.CreateHtmlFragment(textArea.Document, highlighter, selectedSegment, options));
      }
      return html.ToString();
    }
    
    /// <inheritdoc/>
    public abstract override bool Equals(object obj);
    
    /// <inheritdoc/>
    public abstract override int GetHashCode();
    
    /// <summary>
    /// Gets whether the specified offset is included in the selection.
    /// </summary>
    /// <returns>True, if the selection contains the offset (selection borders inclusive);
    /// otherwise, false.</returns>
    public virtual bool Contains(int offset)
    {
      if (this.IsEmpty)
        return false;
      if (this.SurroundingSegment.Contains(offset, 0)) {
        foreach (ISegment s in this.Segments) {
          if (s.Contains(offset, 0)) {
            return true;
          }
        }
      }
      return false;
    }
    
    /// <summary>
    /// Creates a data object containing the selection's text.
    /// </summary>
    public virtual DataObject CreateDataObject(TextArea textArea)
    {
      DataObject data = new DataObject();
      
      // Ensure we use the appropriate newline sequence for the OS
      string text = TextUtilities.NormalizeNewLines(GetText(), Environment.NewLine);
      
      // Enable drag/drop to Word, Notepad++ and others
      if (EditingCommandHandler.ConfirmDataFormat(textArea, data, DataFormats.UnicodeText)) {
        data.SetText(text);
      }
      
      // Enable drag/drop to SciTe:
      // We cannot use SetText, thus we need to use typeof(string).FullName as data format.
      // new DataObject(object) calls SetData(object), which in turn calls SetData(Type, data),
      // which then uses Type.FullName as format.
      // We immitate that behavior here as well:
      if (EditingCommandHandler.ConfirmDataFormat(textArea, data, typeof(string).FullName)) {
        data.SetData(typeof(string).FullName, text);
      }
      
      // Also copy text in HTML format to clipboard - good for pasting text into Word
      // or to the SharpDevelop forums.
      if (EditingCommandHandler.ConfirmDataFormat(textArea, data, DataFormats.Html)) {
        HtmlClipboard.SetHtml(data, CreateHtmlFragment(new HtmlOptions(textArea.Options)));
      }
      return data;
    }
  }
}