DocumentFlow.Ghostscript/API/GhostScript32.cs - ksen - tsv-dd/DocumentFlow

DocumentFlow.Ghostscript/API/GhostScript32.cs
65 строк2 KB
Тепляшин Сергей
Версия 2023.9.25
25 сен 2023, 17:00
25 сен 2023, 17:00d85f975
//-----------------------------------------------------------------------
// Copyright © 2010-2023 Тепляшин Сергей Васильевич. 
// Contacts: <sergio.teplyashin@yandex.ru>
// License: https://opensource.org/licenses/GPL-3.0
// Git: https://github.com/mephraim/ghostscriptsharp
// Date: 24.09.2023
//-----------------------------------------------------------------------

using System.Runtime.InteropServices;

namespace DocumentFlow.Ghostscript.API;

public partial class GhostScript32
{
    [DllImport("gsdll32.dll", EntryPoint = "gsapi_new_instance")]
    private static extern int CreateAPIInstance(out IntPtr pinstance, IntPtr caller_handle);

    [DllImport("gsdll32.dll", EntryPoint = "gsapi_init_with_args")]
    private static extern int InitAPI(IntPtr instance, int argc, string[] argv);

    [DllImport("gsdll32.dll", EntryPoint = "gsapi_exit")]
    private static extern int ExitAPI(IntPtr instance);

    [DllImport("gsdll32.dll", EntryPoint = "gsapi_delete_instance")]
    private static extern void DeleteAPIInstance(IntPtr instance);

    /// <summary>
    /// Calls the Ghostscript API with a collection of arguments to be passed to it
    /// </summary>
    public static void CallAPI(string[] args)
    {
        // Get a pointer to an instance of the Ghostscript API and run the API with the current arguments
        lock (resourceLock)
        {
            CreateAPIInstance(out nint gsInstancePtr, IntPtr.Zero);
            try
            {
                int result = InitAPI(gsInstancePtr, args.Length, args);

                if (result < 0)
                {
                    throw new ExternalException("Ghostscript conversion error", result);
                }
            }
            finally
            {
                Cleanup(gsInstancePtr);
            }
        }
    }

    /// <summary>
    /// Frees up the memory used for the API arguments and clears the Ghostscript API instance
    /// </summary>
    private static void Cleanup(IntPtr gsInstancePtr)
    {
        _ = ExitAPI(gsInstancePtr);
        DeleteAPIInstance(gsInstancePtr);
    }

    /// <summary>
    /// GS can only support a single instance, so we need to bottleneck any multi-threaded systems.
    /// </summary>
    private static object resourceLock = new();
}