Asn1Import.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Text;
using System.Threading.Tasks;
using Waher.Content.Asn1.Exceptions;
 
namespace Waher.Content.Asn1.Model
{
    public class Asn1Import : Asn1Node
    {
        private readonly string[] identifiers;
        private readonly string module;
        private readonly Asn1Document document;
        private Asn1Document importedDocument;
 
        public Asn1Import(string[] Identifiers, string Module, Asn1Document Document)
        {
            this.identifiers = Identifiers;
            this.module = Module;
            this.document = Document;
            this.importedDocument = null;
        }
 
        public string[] Identifiers => this.identifiers;
 
        public string Module => this.module;
 
        public async Task<Asn1Document> LoadDocument()
        {
            if (!(this.importedDocument is null))
                return this.importedDocument;
 
            string Folder = Path.GetDirectoryName(this.document.Location);
            string Extension = Path.GetExtension(this.document.Location);
            string FileName = Path.Combine(Folder, this.module) + Extension;
 
            if (!File.Exists(FileName))
            {
                FileName = null;
 
                foreach (string ImportFolder in this.document.ImportFolders)
                {
                    FileName = Path.Combine(ImportFolder, this.module) + Extension;
                    if (File.Exists(FileName))
                        break;
                    else
                        FileName = null;
                }
 
                if (FileName is null)
                    throw new FileNotFoundException("Unable to find import file for module " + this.module);
            }
 
            this.importedDocument = await Asn1Document.FromFile(FileName, this.document.ImportFolders);
 
            return this.importedDocument;
        }
 
    }
}