StyleRepository.cs

/*
 * NanoXLSX is a small .NET library to generate and read XLSX (Microsoft Excel 2007 or newer) files in an easy and native way
 * Copyright Raphael Stoeckli © 2025
 * This library is licensed under the MIT License.
 * You find a copy of the license in project folder or on: http://opensource.org/licenses/MIT
 */
 
using System.Collections.Generic;
 
namespace NanoXLSX.Styles
{
    public class StyleRepository
    {
        private readonly object lockObject = new object();
 
        private static StyleRepository instance;

        public static StyleRepository Instance
        {
            get
            {
                instance = instance ?? new StyleRepository();
                return instance;
            }
        }
 
        private Dictionary<int, Style> styles;

        internal bool ImportInProgress { get; set; }

        public Dictionary<int, Style> Styles { get => styles; }

        private StyleRepository()
        {
            styles = new Dictionary<int, Style>();
        }

        public Style AddStyle(Style style)
        {
            lock (lockObject)
            {
                if (style == null)
                {
                    return null;
                }
                int hashCode = style.GetHashCode();
                if (!styles.TryGetValue(hashCode, out var value))
                {
                    value = style;
                    styles.Add(hashCode, value);
                }
                return value;
            }
        }

        public void FlushStyles()
        {
            styles.Clear();
        }
 
    }
}