gitextensions-ICSharpCode.TextEditor/Project/Src/Document/HighlightingStrategy/TextWord.cs

// <file>
//     <copyright see="prj:///doc/copyright.txt"/>
//     <license see="prj:///doc/license.txt"/>
//     <owner name="Mike Krüger" email="mike@icsharpcode.net"/>
//     <version>$Revision$</version>
// </file>

using System;
using System.Diagnostics;
using System.Drawing;

namespace ICSharpCode.TextEditor.Document
{
    public enum TextWordType
    {
        Word,
        Space,
        Tab
    }

    /// <summary>
    ///     This class represents single words with color information, two special versions of a word are
    ///     spaces and tabs.
    /// </summary>
    public class TextWord
    {
        private readonly IDocument document;
        private readonly LineSegment line;
        private HighlightColor color;

        protected TextWord()
        {
        }

        // TAB
        public TextWord(IDocument document, LineSegment line, int offset, int length, HighlightColor color, bool hasDefaultColor)
        {
            Debug.Assert(document != null);
            Debug.Assert(line != null);
            Debug.Assert(color != null);

            this.document = document;
            this.line = line;
            Offset = offset;
            Length = length;
            this.color = color;
            HasDefaultColor = hasDefaultColor;
        }

        public static TextWord Space { get; } = new SpaceTextWord();

        public static TextWord Tab { get; } = new TabTextWord();

        public int Offset { get; }

        public int Length { get; private set; }

        public bool HasDefaultColor { get; }

        public virtual TextWordType Type => TextWordType.Word;

        public string Word
        {
            get
            {
                if (document == null)
                    return string.Empty;
                return document.GetText(line.Offset + Offset, Length);
            }
        }

        public Color Color
        {
            get
            {
                if (color == null)
                    return SystemColors.WindowText;
                return color.Color;
            }
        }

        public bool Bold
        {
            get
            {
                if (color == null)
                    return false;
                return color.Bold;
            }
        }

        public bool Italic
        {
            get
            {
                if (color == null)
                    return false;
                return color.Italic;
            }
        }

        public HighlightColor SyntaxColor
        {
            get => color;
            set
            {
                Debug.Assert(value != null);
                color = value;
            }
        }

        public virtual bool IsWhiteSpace => false;

        /// <summary>
        ///     Splits the <paramref name="word" /> into two parts: the part before <paramref name="pos" /> is assigned to
        ///     the reference parameter <paramref name="word" />, the part after <paramref name="pos" /> is returned.
        /// </summary>
        public static TextWord Split(ref TextWord word, int pos)
        {
#if DEBUG
            if (word.Type != TextWordType.Word)
                throw new ArgumentException("word.Type must be Word");
            if (pos <= 0)
                throw new ArgumentOutOfRangeException(nameof(pos), pos, "pos must be > 0");
            if (pos >= word.Length)
                throw new ArgumentOutOfRangeException(nameof(pos), pos, "pos must be < word.Length");
#endif
            var after = new TextWord(word.document, word.line, word.Offset + pos, word.Length - pos, word.color, word.HasDefaultColor);
            word = new TextWord(word.document, word.line, word.Offset, pos, word.color, word.HasDefaultColor);
            return after;
        }

        public virtual Font GetFont(FontContainer fontContainer)
        {
            return color.GetFont(fontContainer);
        }

        /// <summary>
        ///     Converts a <see cref="TextWord" /> instance to string (for debug purposes)
        /// </summary>
        public override string ToString()
        {
            return "[TextWord: Word = " + Word + ", Color = " + Color + "]";
        }

        public sealed class SpaceTextWord : TextWord
        {
            public SpaceTextWord()
            {
                Length = 1;
            }

            public SpaceTextWord(HighlightColor color)
            {
                Length = 1;
                SyntaxColor = color;
            }

            public override TextWordType Type => TextWordType.Space;

            public override bool IsWhiteSpace => true;

            public override Font GetFont(FontContainer fontContainer)
            {
                return null;
            }
        }

        public sealed class TabTextWord : TextWord
        {
            public TabTextWord()
            {
                Length = 1;
            }

            public TabTextWord(HighlightColor color)
            {
                Length = 1;
                SyntaxColor = color;
            }

            public override TextWordType Type => TextWordType.Tab;

            public override bool IsWhiteSpace => true;

            public override Font GetFont(FontContainer fontContainer)
            {
                return null;
            }
        }
    }
}