[Symbian Installation File] Implement IsOpened().

Aaru.Archives/Symbian/Open.cs

@@ -0,0 +1,43 @@
+// /***************************************************************************
+// Aaru Data Preservation Suite
+// ----------------------------------------------------------------------------
+//
+// Filename       : Symbian.cs
+// Author(s)      : Natalia Portillo <claunia@claunia.com>
+//
+// Component      : Symbian plugin.
+//
+// --[ Description ] ----------------------------------------------------------
+//
+//     Identifies Symbian installer (.sis) packages and shows information.
+//
+// --[ License ] --------------------------------------------------------------
+//
+//     This library is free software; you can redistribute it and/or modify
+//     it under the terms of the GNU Lesser General Public License as
+//     published by the Free Software Foundation; either version 2.1 of the
+//     License, or (at your option) any later version.
+//
+//     This library is distributed in the hope that it will be useful, but
+//     WITHOUT ANY WARRANTY; without even the implied warranty of
+//     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+//     Lesser General Public License for more details.
+//
+//     You should have received a copy of the GNU Lesser General Public
+//     License along with this library; if not, see <http://www.gnu.org/licenses/>.
+//
+// ----------------------------------------------------------------------------
+// Copyright © 2011-2023 Natalia Portillo
+// ****************************************************************************/
+
+namespace Aaru.Archives;
+
+public sealed partial class Symbian
+{
+#region IArchive Members
+
+    /// <inheritdoc />
+    public bool IsOpened() => _opened;
+
+#endregion
+}

Aaru.Archives/Symbian/Symbian.cs

@@ -43,8 +43,8 @@ public sealed partial class Symbian : IArchive
     const string            MODULE_NAME = "Symbian Installation File Plugin";
     Encoding                _encoding;
     List<DecodedFileRecord> _files;
-
-    bool _release6;
+    bool                    _opened;
+    bool                    _release6;
 
 #region IArchive Members
 

Aaru.Archives/Symbian/Unsupported.cs

@@ -48,9 +48,6 @@ public sealed partial class Symbian
     /// <inheritdoc />
     public ErrorNumber Open(IFilter filter) => throw new NotImplementedException();
 
-    /// <inheritdoc />
-    public bool IsOpened() => throw new NotImplementedException();
-
     /// <inheritdoc />
     public void Close()
     {