Added decompressor initial process

Duplicati/Library/Main/Operation/Restore/VolumeDecompressor.cs

@@ -0,0 +1,45 @@
+using System;
+using System.Linq;
+using System.Threading.Tasks;
+using CoCoL;
+using Duplicati.Library.Main.Database;
+using Duplicati.Library.Main.Volumes;
+
+namespace Duplicati.Library.Main.Operation.Restore
+{
+    internal class VolumeDecompressor
+    {
+        public static Task Run(LocalRestoreDatabase db, Options options)
+        {
+            return AutomationExtensions.RunTask(
+            new
+            {
+                Input = Channels.decryptedVolume.ForRead,
+                Output = Channels.decompressedVolumes.ForWrite
+            },
+            async self =>
+            {
+                while (true)
+                {
+                    var (volume_id, volume) = await self.Input.ReadAsync();
+
+                    var bids = db.Connection.CreateCommand().ExecuteReaderEnumerable(@$"SELECT ID, Hash, Size FROM Block WHERE VolumeID = ""{volume_id}""").Select(x => (x.GetInt64(0), x.GetString(1), x.GetInt64(2))).ToArray();
+
+                    using (var blocks = new BlockVolumeReader(options.CompressionModule, volume, options))
+                    {
+                        var volume_blocks = blocks.Blocks.ToArray();
+                        for (int i = 0; i < volume_blocks.Length; i++)
+                        {
+                            byte[] buffer = new byte[options.Blocksize];
+
+                            System.Diagnostics.Debug.Assert(volume_blocks[i].Key == bids[i].Item2);
+                            blocks.ReadBlock(volume_blocks[i].Key, buffer);
+
+                            await self.Output.WriteAsync((bids[i].Item1, buffer[..(int)bids[i].Item3]));
+                        }
+                    }
+                }
+            });
+        }
+    }
+}

Duplicati/Library/Main/Operation/RestoreHandler.cs

@@ -145,11 +145,11 @@ namespace Duplicati.Library.Main.Operation
                     all = Task.WhenAll(
                         [
                             Restore.FileLister.Run(db, backend, filter, m_options, m_result),
-                            ..Enumerable.Range(0, parallelism).Select(i =>
-                                Restore.FileProcessor.Run(db, fileprocessor_requests[i], fileprocessor_responses[i])),
+                            ..Enumerable.Range(0, parallelism).Select(i => Restore.FileProcessor.Run(db, fileprocessor_requests[i], fileprocessor_responses[i])),
                             Restore.BlockManager.Run(db, fileprocessor_requests, fileprocessor_responses),
                             ..Enumerable.Range(0, parallelism).Select(i => Restore.VolumeDownloader.Run(backend, m_options)),
-                            ..Enumerable.Range(0, parallelism).Select(i => Restore.VolumeDecrypter.Run())
+                            ..Enumerable.Range(0, parallelism).Select(i => Restore.VolumeDecrypter.Run()),
+                            ..Enumerable.Range(0, parallelism).Select(i => Restore.VolumeDecompressor.Run(db, m_options))
                         ]
                     );
                 }