Added export and import of plugin archives (#885)

Co-authored-by: Thorsten Sommer <SommerEngineering@users.noreply.github.com>

app/MindWork AI Studio/Tools/PluginSystem/PluginArchive.cs

@@ -0,0 +1,80 @@
+using System.IO.Compression;
+
+namespace AIStudio.Tools.PluginSystem;
+
+public static class PluginArchive
+{
+    /// <summary>
+    /// The file extension of plugin archives.
+    /// </summary>
+    /// <remarks>
+    /// Keep in sync with SHARE_FILE_EXTENSION in runtime/src/share_sheet.rs: the runtime only hands
+    /// archives with this extension to the native share sheet.
+    /// </remarks>
+    public const string PLUGIN_FILE_EXTENSION = ".mwplugin";
+
+
+    // Compatibility shim for Windows-created ZIPs with backslashes in entry names (dotnet/runtime#27620);
+    // remove after dotnet/runtime#27620 and #41914 are fixed.
+    // See documentation/compatibility-shims/2026-07-plugin-archive-zip-backslashes.md.
+    public static void Extract(string sourceArchiveFileName, string destinationDirectory)
+    {
+        using var archive = ZipFile.OpenRead(sourceArchiveFileName);
+        Directory.CreateDirectory(destinationDirectory);
+
+        var destinationDirectoryFullPath = Path.GetFullPath(destinationDirectory);
+        if (!destinationDirectoryFullPath.EndsWith(Path.DirectorySeparatorChar))
+            destinationDirectoryFullPath += Path.DirectorySeparatorChar;
+
+        foreach (var entry in archive.Entries)
+        {
+            var normalizedEntryName = NormalizeEntryName(entry.FullName);
+            var destinationPath = GetEntryDestinationPath(destinationDirectoryFullPath, normalizedEntryName);
+
+            if (normalizedEntryName.EndsWith('/'))
+            {
+                if (entry.Length != 0)
+                    throw new InvalidDataException($"The plugin archive contains a directory entry with data: '{entry.FullName}'.");
+
+                Directory.CreateDirectory(destinationPath);
+                continue;
+            }
+
+            Directory.CreateDirectory(Path.GetDirectoryName(destinationPath)!);
+            entry.ExtractToFile(destinationPath);
+        }
+    }
+
+    private static string NormalizeEntryName(string entryName)
+    {
+        var normalizedEntryName = entryName.Replace('\\', '/');
+        if (string.IsNullOrWhiteSpace(normalizedEntryName))
+            throw new InvalidDataException("The plugin archive contains an empty entry name.");
+
+        if (normalizedEntryName.Contains('\0'))
+            throw new InvalidDataException($"The plugin archive contains an invalid entry name: '{entryName}'.");
+
+        if (normalizedEntryName.StartsWith('/'))
+            throw new InvalidDataException($"The plugin archive contains a rooted entry name: '{entryName}'.");
+
+        if (normalizedEntryName is [_, ':', ..])
+            throw new InvalidDataException($"The plugin archive contains a drive-qualified entry name: '{entryName}'.");
+
+        var pathSegments = normalizedEntryName.Split('/', StringSplitOptions.RemoveEmptyEntries);
+        if (pathSegments.Length == 0 || pathSegments.Any(segment => segment is "." or ".."))
+            throw new InvalidDataException($"The plugin archive contains an unsafe entry name: '{entryName}'.");
+
+        return normalizedEntryName;
+    }
+
+    private static string GetEntryDestinationPath(string destinationDirectoryFullPath, string normalizedEntryName)
+    {
+        var pathSegments = normalizedEntryName.Split('/', StringSplitOptions.RemoveEmptyEntries);
+        var relativePath = Path.Combine(pathSegments);
+        var destinationPath = Path.GetFullPath(Path.Combine(destinationDirectoryFullPath, relativePath));
+        if (!destinationPath.StartsWith(destinationDirectoryFullPath, StringComparison.Ordinal))
+            throw new InvalidDataException($"The plugin archive contains an entry outside the destination directory: '{normalizedEntryName}'.");
+
+        return destinationPath;
+    }
+}