ReaderPlugInHandler.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 © 2026
 * 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.Diagnostics.CodeAnalysis;
using System.IO;
using NanoXLSX.Interfaces;
using NanoXLSX.Interfaces.Reader;
using NanoXLSX.Registry;
 
namespace NanoXLSX.Internal.Readers
{
    internal static class ReaderPlugInHandler
    {
        [ExcludeFromCodeCoverage] // No testable logic, only plug-in handling
        internal static void HandleInlineQueuePlugins(Stream stream, Workbook workbook, string queueUuid, IOptions readerOptions, int? index)
        {
            if (stream == null)
            {
                return;
            }
            // Inline plug-ins reset Position to 0 to re-read the part. If the caller passed a
            // non-seekable stream (e.g. a deflate stream from a ZIP entry), the contract can only
            // be honored by buffering once. Skip the buffer when no inline plug-ins exist.
            Stream working = stream;
            MemoryStream owned = null;
            if (!stream.CanSeek && PlugInLoader.HasQueuePlugins(queueUuid))
            {
                owned = new MemoryStream();
                stream.CopyTo(owned);
                owned.Position = 0;
                working = owned;
            }
            try
            {
                IPluginInlineReader queueReader = null;
                string lastUuid = null;
                do
                {
                    string currentUuid;
                    queueReader = PlugInLoader.GetNextQueuePlugIn<IPluginInlineReader>(queueUuid, lastUuid, out currentUuid);
                    if (queueReader != null)
                    {
                        if (working.CanSeek)
                        {
                            working.Position = 0;
                        }
                        queueReader.Init(working, workbook, readerOptions, index);
                        queueReader.Execute();
                        lastUuid = currentUuid;
                    }
                    else
                    {
                        lastUuid = null;
                    }
 
                } while (queueReader != null);
            }
            finally
            {
                owned?.Dispose();
            }
        }
    }
}