IVirtualDiskProvider abstraction, need a lot of work on the class names.

src/NzbDrone.Core/NzbDrone.Core.csproj

@@ -946,10 +946,14 @@
     <Compile Include="ProgressMessaging\ProgressMessageContext.cs" />
     <Compile Include="Qualities\QualitySource.cs" />
     <Compile Include="Qualities\Revision.cs" />
-    <Compile Include="TransferProviders\CustomTransferProvider.cs" />
+    <Compile Include="TransferProviders\Providers\DefaultTransfer.cs" />
+    <Compile Include="TransferProviders\Providers\Dummy.cs" />
+    <Compile Include="TransferProviders\TransferProviderDefinition.cs" />
+    <Compile Include="TransferProviders\TransferProviderRepository.cs" />
+    <Compile Include="TransferProviders\Providers\CustomTransfer.cs" />
     <Compile Include="TransferProviders\ITransferProvider.cs" />
     <Compile Include="TransferProviders\IVirtualDiskProvider.cs" />
-    <Compile Include="TransferProviders\MountTransferProvider.cs" />
+    <Compile Include="TransferProviders\Providers\MountTransfer.cs" />
     <Compile Include="TransferProviders\old\RemotePathMapping.cs" />
     <Compile Include="TransferProviders\old\RemotePathMappingRepository.cs" />
     <Compile Include="TransferProviders\old\RemotePathMappingService.cs" />
@@ -1126,7 +1130,10 @@
     <Compile Include="ThingiProvider\Status\ProviderStatusRepository.cs" />
     <Compile Include="ThingiProvider\Status\ProviderStatusServiceBase.cs" />
     <Compile Include="TinyTwitter.cs" />
+    <Compile Include="TransferProviders\TransferProviderBase.cs" />
     <Compile Include="TransferProviders\TransferProviderFactory.cs" />
+    <Compile Include="TransferProviders\TransferProviderService.cs" />
+    <Compile Include="TransferProviders\TransferTask.cs" />
     <Compile Include="Tv\Actor.cs" />
     <Compile Include="Tv\AddSeriesOptions.cs" />
     <Compile Include="Tv\AddSeriesService.cs" />

src/NzbDrone.Core/TransferProviders/ITransferProvider.cs

@@ -5,10 +5,16 @@ using NzbDrone.Core.ThingiProvider;
 
 namespace NzbDrone.Core.TransferProviders
 {
-    public interface ITransferProvider : IProvider, IVirtualDiskProvider
+    public interface ITransferProvider : IProvider
     {
+        // TODO: Perhaps change 'string' to 'DownloadClientPath' struct/class so we're more typesafe.
+
         // Whether the TransferProvider is ready to be accessed. (Useful for external transfers that may not have finished yet)
         bool IsAvailable(string downloadClientPath);
         bool IsAvailable(DownloadClientItem item);
+
+        // Returns a wrapper for the specific download. Optionally we might want to supply a 'tempDir' that's close to the series path, in case the TransferProvider needs an intermediate location.
+        IVirtualDiskProvider GetFileSystemWrapper(string downloadClientPath);
+        IVirtualDiskProvider GetFileSystemWrapper(DownloadClientItem item);
     }
 }

src/NzbDrone.Core/TransferProviders/IVirtualDiskProvider.cs

@@ -10,7 +10,16 @@ namespace NzbDrone.Core.TransferProviders
     // Any Move/Copy action should return an asynchroneous context representing the transfer in progress. So it can be shown in CDH / Activity->Queue.
     public interface IVirtualDiskProvider // : IDiskProvider
     {
+        // Whether the VirtualFileSystem supports direct streaming of the file content.
+        bool SupportStreaming { get; }
+
+        // Returns recursive list of all files in the 'volume'/'filesystem'/'dataset' (whatever we want to call it).
+        string[] GetFiles();
+
         // Copies file from the virtual filesystem to the actual one.
         TransferTask CopyFile(string vfsSourcePath, string destinationPath);
+
+        // Move file from the virtual filesystem to the actual one.
+        TransferTask MoveFile(string vfsSourcePath, string destinationPath);
     }
 }

src/NzbDrone.Core/TransferProviders/Providers/DefaultTransfer.cs

@@ -0,0 +1,41 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using FluentValidation.Results;
+using NzbDrone.Core.ThingiProvider;
+
+namespace NzbDrone.Core.TransferProviders.Providers
+{
+    // Represents a local filesystem transfer.
+    class DefaultTransfer : TransferProviderBase<NullConfig>
+    {
+        public override IEnumerable<ProviderDefinition> DefaultDefinitions
+        {
+            get
+            {
+                yield return new TransferProviderDefinition
+                {
+                    Enable = true,
+                    Name = "Default",
+                    ImplementationName = nameof(DefaultTransfer),
+                    Implementation = nameof(DefaultTransfer),
+                    Settings = NullConfig.Instance
+                };
+            }
+        }
+        public override string Link
+        {
+            get { throw new NotImplementedException(); }
+        }
+
+        public override string Name
+        {
+            get { throw new NotImplementedException(); }
+        }
+
+        public override ValidationResult Test()
+        {
+            throw new NotImplementedException();
+        }
+    }
+}

src/NzbDrone.Core/TransferProviders/Providers/Dummy.cs

@@ -0,0 +1,28 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using FluentValidation.Results;
+using NzbDrone.Core.ThingiProvider;
+
+namespace NzbDrone.Core.TransferProviders.Providers
+{
+    // Marks the files are permanently unavailable. Perhaps useful in fire-and-forget.
+    class Dummy : TransferProviderBase<NullConfig>
+    {
+        public override string Link
+        {
+            get { throw new NotImplementedException(); }
+        }
+
+        public override string Name
+        {
+            get { throw new NotImplementedException(); }
+        }
+
+        public override ValidationResult Test()
+        {
+            throw new NotImplementedException();
+        }
+    }
+}

src/NzbDrone.Core/TransferProviders/TransferProviderBase.cs

@@ -0,0 +1,26 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using FluentValidation.Results;
+using NzbDrone.Core.ThingiProvider;
+
+namespace NzbDrone.Core.TransferProviders
+{
+    public abstract class TransferProviderBase<TSettings> : ITransferProvider where TSettings : IProviderConfig, new()
+    {
+        public abstract string Name { get; }
+
+        public Type ConfigContract => typeof(TSettings);
+
+        public virtual ProviderMessage Message => null;
+
+        public virtual IEnumerable<ProviderDefinition> DefaultDefinitions => new List<ProviderDefinition>();
+
+        public ProviderDefinition Definition { get; set; }
+        public abstract ValidationResult Test();
+
+        public abstract string Link { get; }
+
+        public virtual object RequestAction(string action, IDictionary<string, string> query) { return null; }
+    }
+}

src/NzbDrone.Core/TransferProviders/TransferProviderDefinition.cs

@@ -0,0 +1,14 @@
+using System;
+using System.Linq;
+using NzbDrone.Core.ThingiProvider;
+
+namespace NzbDrone.Core.TransferProviders
+{
+    public class TransferProviderDefinition : ProviderDefinition
+    {
+        public int DownloadClientId { get; set; }
+        // OR
+        // Path could be extracted from download client.
+        //public string DownloadClientRootPath { get; set; }
+    }
+}

src/NzbDrone.Core/TransferProviders/TransferProviderFactory.cs

@@ -11,36 +11,10 @@ using NzbDrone.Core.Validation;
 
 namespace NzbDrone.Core.TransferProviders
 {
-    public class TransferProviderDefinition : ProviderDefinition
-    {
-    }
-
     public interface ITransferProviderFactory : IProviderFactory<ITransferProvider, TransferProviderDefinition>
     {
     }
 
-    public abstract class TransferProviderBase<TSettings> : ITransferProvider where TSettings : IProviderConfig, new()
-    {
-        public abstract string Name { get; }
-
-        public Type ConfigContract => typeof(TSettings);
-
-        public virtual ProviderMessage Message => null;
-
-        public IEnumerable<ProviderDefinition> DefaultDefinitions => new List<ProviderDefinition>();
-        public ProviderDefinition Definition { get; set; }
-        public abstract ValidationResult Test();
-
-        public abstract string Link { get; }
-
-        public virtual object RequestAction(string action, IDictionary<string, string> query) { return null; }
-    }
-
-    public interface ITransferProviderRepository : IProviderRepository<TransferProviderDefinition>
-    {
-
-    }
-
     public class TransferProviderFactory : ProviderFactory<ITransferProvider, TransferProviderDefinition>, ITransferProviderFactory
     {
         public TransferProviderFactory(ITransferProviderRepository providerRepository, IEnumerable<ITransferProvider> providers, IContainer container, IEventAggregator eventAggregator, Logger logger)

src/NzbDrone.Core/TransferProviders/TransferProviderRepository.cs

@@ -0,0 +1,11 @@
+using System;
+using System.Linq;
+using NzbDrone.Core.ThingiProvider;
+
+namespace NzbDrone.Core.TransferProviders
+{
+    public interface ITransferProviderRepository : IProviderRepository<TransferProviderDefinition>
+    {
+
+    }
+}

src/NzbDrone.Core/TransferProviders/TransferProviderService.cs

@@ -0,0 +1,40 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using NLog;
+using NzbDrone.Core.Download;
+using NzbDrone.Core.ThingiProvider;
+using NzbDrone.Core.TransferProviders.Providers;
+
+namespace NzbDrone.Core.TransferProviders
+{
+    public interface ITransferProviderService
+    {
+        ITransferProvider GetProvider(int downloadClientId);
+    }
+
+    public class TransferProviderService : ITransferProviderService
+    {
+        private readonly ITransferProviderFactory _transferProviderFactory;
+        private readonly Logger _logger;
+
+        public TransferProviderService(ITransferProviderFactory transferProviderFactory, Logger logger)
+        {
+            _transferProviderFactory = transferProviderFactory;
+            _logger = logger;
+        }
+
+        public ITransferProvider GetProvider(int downloadClientId)
+        {
+            var definition = _transferProviderFactory.All().FirstOrDefault(v => v.DownloadClientId == downloadClientId);
+
+            if (definition == null)
+            {
+                definition = _transferProviderFactory.GetDefaultDefinitions().First(v => v.ImplementationName == nameof(DefaultTransfer));
+            }
+
+            return _transferProviderFactory.GetInstance(definition);
+        }
+    }
+}