Handle Move/Copy to same file via different mount/symlink

src/NzbDrone.Common.Test/DiskTests/DiskTransferServiceFixture.cs

@@ -451,6 +451,38 @@ namespace NzbDrone.Common.Test.DiskTests
             VerifyMoveFolder(original.FullName, source.FullName, destination.FullName);
         }
 
+        [Test]
+        public void MoveFolder_should_detect_caseinsensitive_parents()
+        {
+            WithRealDiskProvider();
+
+            var original = GetFilledTempFolder();
+            var root = new DirectoryInfo(GetTempFilePath());
+            var source = new DirectoryInfo(root.FullName + "A/series");
+            var destination = new DirectoryInfo(root.FullName + "a/series");
+
+            Subject.TransferFolder(original.FullName, source.FullName, TransferMode.Copy);
+
+            Assert.Throws<IOException>(() => Subject.TransferFolder(source.FullName, destination.FullName, TransferMode.Move));
+        }
+
+        [Test]
+        public void MoveFolder_should_rename_caseinsensitive_folder()
+        {
+            WithRealDiskProvider();
+
+            var original = GetFilledTempFolder();
+            var root = new DirectoryInfo(GetTempFilePath());
+            var source = new DirectoryInfo(root.FullName + "A/series");
+            var destination = new DirectoryInfo(root.FullName + "A/Series");
+
+            Subject.TransferFolder(original.FullName, source.FullName, TransferMode.Copy);
+
+            Subject.TransferFolder(source.FullName, destination.FullName, TransferMode.Move);
+
+            source.FullName.GetActualCasing().Should().Be(destination.FullName);
+        }
+
         [Test]
         public void should_throw_if_destination_is_readonly()
         {
@@ -747,6 +779,10 @@ namespace NzbDrone.Common.Test.DiskTests
                 .Setup(v => v.CreateFolder(It.IsAny<string>()))
                 .Callback<string>(v => Directory.CreateDirectory(v));
 
+            Mocker.GetMock<IDiskProvider>()
+                .Setup(v => v.MoveFolder(It.IsAny<string>(), It.IsAny<string>()))
+                .Callback<string, string>((v, r) => Directory.Move(v, r));
+
             Mocker.GetMock<IDiskProvider>()
                 .Setup(v => v.DeleteFolder(It.IsAny<string>(), It.IsAny<bool>()))
                 .Callback<string, bool>((v, r) => Directory.Delete(v, r));

src/NzbDrone.Common/Disk/DiskTransferService.cs

@@ -1,6 +1,7 @@
 using System;
 using System.IO;
 using System.Linq;
+using System.Runtime.InteropServices;
 using System.Threading;
 using NLog;
 using NzbDrone.Common.EnsureThat;
@@ -28,11 +29,53 @@ namespace NzbDrone.Common.Disk
             _logger = logger;
         }
 
+        private string ResolveRealParentPath(string path)
+        {
+            var parentPath = path.GetParentPath();
+            if (!_diskProvider.FolderExists(path))
+            {
+                return path;
+            }
+
+            parentPath = parentPath.GetActualCasing();
+            return parentPath + Path.DirectorySeparatorChar + Path.GetFileName(path);
+        }
+        
         public TransferMode TransferFolder(string sourcePath, string targetPath, TransferMode mode)
         {
             Ensure.That(sourcePath, () => sourcePath).IsValidPath();
             Ensure.That(targetPath, () => targetPath).IsValidPath();
 
+            sourcePath = ResolveRealParentPath(sourcePath);
+            targetPath = ResolveRealParentPath(targetPath);
+
+            _logger.Debug("{0} Directory [{1}] > [{2}]", mode, sourcePath, targetPath);
+
+            if (sourcePath == targetPath)
+            {
+                throw new IOException(string.Format("Source and destination can't be the same {0}", sourcePath));
+            }
+
+            if (mode == TransferMode.Move && sourcePath.PathEquals(targetPath, StringComparison.InvariantCultureIgnoreCase) && _diskProvider.FolderExists(targetPath))
+            {
+                // Move folder out of the way to allow case-insensitive renames
+                var tempPath = sourcePath + ".backup~";
+                _logger.Trace("Rename Intermediate Directory [{0}] > [{1}]", sourcePath, tempPath);
+                _diskProvider.MoveFolder(sourcePath, tempPath);
+
+                if (!_diskProvider.FolderExists(targetPath))
+                {
+                    _logger.Trace("Rename Intermediate Directory [{0}] > [{1}]", tempPath, targetPath);
+                    _logger.Debug("Rename Directory [{0}] > [{1}]", sourcePath, targetPath);
+                    _diskProvider.MoveFolder(tempPath, targetPath);
+                    return mode;
+                }
+
+                // There were two separate folders, revert the intermediate rename and let the recursion deal with it
+                _logger.Trace("Rename Intermediate Directory [{0}] > [{1}]", tempPath, sourcePath);
+                _diskProvider.MoveFolder(tempPath, sourcePath);
+            }
+
             if (mode == TransferMode.Move && !_diskProvider.FolderExists(targetPath))
             {
                 var sourceMount = _diskProvider.GetMount(sourcePath);
@@ -41,7 +84,7 @@ namespace NzbDrone.Common.Disk
                 // If we're on the same mount, do a simple folder move.
                 if (sourceMount != null && targetMount != null && sourceMount.RootDirectory == targetMount.RootDirectory)
                 {
-                    _logger.Debug("Move Directory [{0}] > [{1}]", sourcePath, targetPath);
+                    _logger.Debug("Rename Directory [{0}] > [{1}]", sourcePath, targetPath);
                     _diskProvider.MoveFolder(sourcePath, targetPath);
                     return mode;
                 }
@@ -74,6 +117,13 @@ namespace NzbDrone.Common.Disk
 
             if (mode.HasFlag(TransferMode.Move))
             {
+                var totalSize = _diskProvider.GetFileInfos(sourcePath).Sum(v => v.Length);
+
+                if (totalSize > (100 * 1024L * 1024L))
+                {
+                    throw new IOException($"Large files still exist in {sourcePath} after folder move, not deleting source folder");
+                }
+
                 _diskProvider.DeleteFolder(sourcePath, true);
             }
 
@@ -87,7 +137,10 @@ namespace NzbDrone.Common.Disk
             Ensure.That(sourcePath, () => sourcePath).IsValidPath();
             Ensure.That(targetPath, () => targetPath).IsValidPath();
 
-            _logger.Debug("Mirror [{0}] > [{1}]", sourcePath, targetPath);
+            sourcePath = ResolveRealParentPath(sourcePath);
+            targetPath = ResolveRealParentPath(targetPath);
+
+            _logger.Debug("Mirror Folder [{0}] > [{1}]", sourcePath, targetPath);
 
             if (!_diskProvider.FolderExists(targetPath))
             {
@@ -187,17 +240,22 @@ namespace NzbDrone.Common.Disk
             Ensure.That(sourcePath, () => sourcePath).IsValidPath();
             Ensure.That(targetPath, () => targetPath).IsValidPath();
 
-            _logger.Debug("{0} [{1}] > [{2}]", mode, sourcePath, targetPath);
+            sourcePath = ResolveRealParentPath(sourcePath);
+            targetPath = ResolveRealParentPath(targetPath);
 
-            var originalSize = _diskProvider.GetFileSize(sourcePath);
+            _logger.Debug("{0} [{1}] > [{2}]", mode, sourcePath, targetPath);
 
             if (sourcePath == targetPath)
             {
                 throw new IOException(string.Format("Source and destination can't be the same {0}", sourcePath));
             }
 
+            var originalSize = _diskProvider.GetFileSize(sourcePath);
+
             if (sourcePath.PathEquals(targetPath, StringComparison.InvariantCultureIgnoreCase))
             {
+                // Shortcut for dealing with inplace rename
+
                 if (mode.HasFlag(TransferMode.HardLink) || mode.HasFlag(TransferMode.Copy))
                 {
                     throw new IOException(string.Format("Source and destination can't be the same {0}", sourcePath));
@@ -210,7 +268,7 @@ namespace NzbDrone.Common.Disk
                     _diskProvider.MoveFile(sourcePath, tempPath, true);
                     try
                     {
-                        ClearTargetPath(sourcePath, targetPath, overwrite);
+                        ClearTargetPath(targetPath, overwrite);
 
                         _diskProvider.MoveFile(tempPath, targetPath);
 
@@ -240,7 +298,77 @@ namespace NzbDrone.Common.Disk
                 throw new IOException(string.Format("Destination cannot be a child of the source [{0}] => [{1}]", sourcePath, targetPath));
             }
 
-            ClearTargetPath(sourcePath, targetPath, overwrite);
+            var targetFileExists = _diskProvider.FileExists(targetPath);
+            var targetFilePotentiallySame = targetFileExists && Path.GetFileName(sourcePath).EqualsIgnoreCase(Path.GetFileName(targetPath)) && _diskProvider.GetFileSize(targetPath) == originalSize;
+
+            // If the target file exists and has the same name ans size then it _could_ be that they're actually pointing to the same actual file via softlinks.
+            // This is reasonably easy to determine in linux, but on windows it's more tricky.
+            // Depending on 'overwrite' and Move/Copy we have to take different actions.
+
+            if (targetFileExists)
+            {
+                if (targetFilePotentiallySame)
+                {
+                    var targetBackupPath = targetPath + ".backup~";
+
+                    if (mode.HasFlag(TransferMode.HardLink) || mode.HasFlag(TransferMode.Copy))
+                    {
+                        // Copy doesn't allow renames, only overwrite
+                        if (!overwrite)
+                        {
+                            throw new DestinationAlreadyExistsException($"Destination {targetPath} already exists.");
+                        }
+
+                        _diskProvider.MoveFile(targetPath, targetBackupPath, true);
+                        if (!_diskProvider.FileExists(sourcePath))
+                        {
+                            // They were the same file, Copy/Hardlink can't handle that, so revert and throw
+                            // Note that on windows this can actually cause the casing to change
+                            _diskProvider.MoveFile(targetBackupPath, targetPath);
+
+                            throw new IOException(string.Format("Source and destination can't be the same {0}", sourcePath));
+                        }
+                    }
+                    else if (mode.HasFlag(TransferMode.Move))
+                    {
+                        // Move allows a rename of same file, or overwrite different file
+                        _diskProvider.MoveFile(targetPath, targetBackupPath, true);
+                        if (!_diskProvider.FileExists(sourcePath))
+                        {
+                            // They were the same file, treat this as if it's a rename in place
+                            _diskProvider.MoveFile(targetBackupPath, targetPath);
+
+                            return TransferMode.Move;
+                        }
+                        else
+                        {
+                            // They were different files, only allow the move if overwrite is enabled, otherwise revert and throw
+                            if (overwrite)
+                            {
+                                _diskProvider.DeleteFile(targetBackupPath);
+                            }
+                            else
+                            {
+                                _diskProvider.MoveFile(targetBackupPath, targetPath);
+                                throw new DestinationAlreadyExistsException($"Destination {targetPath} already exists.");
+                            }
+                        }
+                    }
+                    else
+                    {
+                        return TransferMode.None;
+                    }
+                }
+                else
+                {
+                    if (!overwrite)
+                    {
+                        throw new DestinationAlreadyExistsException($"Destination {targetPath} already exists.");
+                    }
+
+                    _diskProvider.DeleteFile(targetPath);
+                }
+            }
 
             if (mode.HasFlag(TransferMode.HardLink))
             {
@@ -315,7 +443,7 @@ namespace NzbDrone.Common.Disk
             return TransferMode.None;
         }
 
-        private void ClearTargetPath(string sourcePath, string targetPath, bool overwrite)
+        private void ClearTargetPath(string targetPath, bool overwrite)
         {
             if (_diskProvider.FileExists(targetPath))
             {