fix: file stream sharing

src/TestableIO.System.IO.Abstractions.TestingHelpers/IMockFileDataAccessor.cs

@@ -1,4 +1,5 @@
-using System.Collections.Generic;
+using System.Collections.Concurrent;
+using System.Collections.Generic;
 using System.Reflection;
 
 namespace System.IO.Abstractions.TestingHelpers;
@@ -110,4 +111,9 @@ public interface IMockFileDataAccessor : IFileSystem
     /// Gets a reference to the underlying file system. 
     /// </summary>
     IFileSystem FileSystem { get; }
+
+    /// <summary>
+    /// Gets a reference to the open file handles.
+    /// </summary>
+    ConcurrentDictionary<string, ConcurrentDictionary<Guid, (FileAccess, FileShare)>> FileHandles { get; }
 }

src/TestableIO.System.IO.Abstractions.TestingHelpers/MockFile.cs

@@ -677,7 +677,7 @@ private FileSystemStream OpenInternal(
         }
         mockFileDataAccessor.AdjustTimes(mockFileData, timeAdjustments);
 
-        return new MockFileStream(mockFileDataAccessor, path, mode, access, options);
+        return new MockFileStream(mockFileDataAccessor, path, mode, access, FileShare.Read, options);
     }
 
     /// <inheritdoc />

src/TestableIO.System.IO.Abstractions.TestingHelpers/MockFileStream.cs

@@ -2,6 +2,7 @@
 using System.Threading;
 using System.Runtime.Versioning;
 using System.Security.AccessControl;
+using System.Collections.Concurrent;
 
 namespace System.IO.Abstractions.TestingHelpers;
 
@@ -31,7 +32,9 @@ public NullFileSystemStream() : base(Null, ".", true)
 
     private readonly IMockFileDataAccessor mockFileDataAccessor;
     private readonly string path;
+    private readonly Guid guid = Guid.NewGuid();
     private readonly FileAccess access = FileAccess.ReadWrite;
+    private readonly FileShare share = FileShare.Read;
     private readonly FileOptions options;
     private readonly MockFileData fileData;
     private bool disposed;
@@ -42,6 +45,7 @@ public MockFileStream(
         string path,
         FileMode mode,
         FileAccess access = FileAccess.ReadWrite,
+        FileShare share = FileShare.Read,
         FileOptions options = FileOptions.None)
         : base(new MemoryStream(),
             path == null ? null : Path.GetFullPath(path),
@@ -51,6 +55,7 @@ public MockFileStream(
         ThrowIfInvalidModeAccess(mode, access);
 
         this.mockFileDataAccessor = mockFileDataAccessor ?? throw new ArgumentNullException(nameof(mockFileDataAccessor));
+        path = mockFileDataAccessor.PathVerifier.FixPath(path);
         this.path = path;
         this.options = options;
 
@@ -97,7 +102,39 @@ public MockFileStream(
             mockFileDataAccessor.AddFile(path, fileData);
         }
 
+        var fileHandlesEntry = mockFileDataAccessor.FileHandles.GetOrAdd(
+            path, 
+            _ => new ConcurrentDictionary<Guid, (FileAccess access, FileShare share)>());
+
+        var requiredShare = AccessToShare(access);
+        foreach (var (existingAccess, existingShare) in fileHandlesEntry.Values)
+        {
+            var existingRequiredShare = AccessToShare(existingAccess);
+            var existingBlocksNew = (existingShare & requiredShare) != requiredShare;
+            var newBlocksExisting = (share & existingRequiredShare) != existingRequiredShare;
+            if (existingBlocksNew || newBlocksExisting)
+            {
+                throw CommonExceptions.ProcessCannotAccessFileInUse(path);
+            }
+        }
+
+        fileHandlesEntry[guid] = (access, share);
         this.access = access;
+        this.share = share;
+    }
+
+    private static FileShare AccessToShare(FileAccess access)
+    {
+        var share = FileShare.None;
+        if (access.HasFlag(FileAccess.Read))
+        {
+            share |= FileShare.Read;
+        }
+        if (access.HasFlag(FileAccess.Write))
+        {
+            share |= FileShare.Write;
+        }
+        return share;
     }
 
     private static void ThrowIfInvalidModeAccess(FileMode mode, FileAccess access)
@@ -144,6 +181,14 @@ protected override void Dispose(bool disposing)
         {
             return;
         }
+        if (mockFileDataAccessor.FileHandles.TryGetValue(path, out var fileHandlesEntry))
+        {
+            fileHandlesEntry.TryRemove(guid, out _);
+            if (fileHandlesEntry.IsEmpty)
+            {
+                mockFileDataAccessor.FileHandles.TryRemove(path, out _);
+            }
+        }
         InternalFlush();
         base.Dispose(disposing);
         OnClose();

src/TestableIO.System.IO.Abstractions.TestingHelpers/MockFileStreamFactory.cs

@@ -41,25 +41,25 @@ public FileSystemStream New(string path, FileMode mode, FileAccess access)
 
     /// <inheritdoc />
     public FileSystemStream New(string path, FileMode mode, FileAccess access, FileShare share)
-        => new MockFileStream(mockFileSystem, path, mode, access);
+        => new MockFileStream(mockFileSystem, path, mode, access, share);
 
     /// <inheritdoc />
     public FileSystemStream New(string path, FileMode mode, FileAccess access, FileShare share, int bufferSize)
-        => new MockFileStream(mockFileSystem, path, mode, access);
+        => new MockFileStream(mockFileSystem, path, mode, access, share);
 
     /// <inheritdoc />
     public FileSystemStream New(string path, FileMode mode, FileAccess access, FileShare share, int bufferSize, bool useAsync)
-        => new MockFileStream(mockFileSystem, path, mode, access);
+        => new MockFileStream(mockFileSystem, path, mode, access, share);
 
     /// <inheritdoc />
     public FileSystemStream New(string path, FileMode mode, FileAccess access, FileShare share, int bufferSize,
         FileOptions options)
-        => new MockFileStream(mockFileSystem, path, mode, access, options);
+        => new MockFileStream(mockFileSystem, path, mode, access, share, options);
 
 #if FEATURE_FILESTREAM_OPTIONS
     /// <inheritdoc />
     public FileSystemStream New(string path, FileStreamOptions options)
-        => new MockFileStream(mockFileSystem, path, options.Mode, options.Access, options.Options);
+        => new MockFileStream(mockFileSystem, path, options.Mode, options.Access, options.Share, options.Options);
 #endif
 
     /// <inheritdoc />

src/TestableIO.System.IO.Abstractions.TestingHelpers/MockFileSystem.cs

@@ -1,3 +1,4 @@
+using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Linq;
 using System.Reflection;
@@ -21,6 +22,10 @@ public class MockFileSystem : FileSystemBase, IMockFileDataAccessor
     private readonly PathVerifier pathVerifier;
 #if FEATURE_SERIALIZABLE
     [NonSerialized]
+#endif
+    private readonly ConcurrentDictionary<string, ConcurrentDictionary<Guid, (FileAccess access, FileShare share)>> fileHandles = new();
+#if FEATURE_SERIALIZABLE
+    [NonSerialized]
 #endif
     private Func<DateTime> dateTimeProvider = defaultDateTimeProvider;
     private static Func<DateTime> defaultDateTimeProvider = () => DateTime.UtcNow;
@@ -114,6 +119,9 @@ public MockFileSystem(IDictionary<string, MockFileData> files, MockFileSystemOpt
     public IFileSystem FileSystem => this;
     /// <inheritdoc />
     public PathVerifier PathVerifier => pathVerifier;
+    /// <inheritdoc />
+    public ConcurrentDictionary<string, ConcurrentDictionary<Guid, (FileAccess, FileShare)>> FileHandles
+    => fileHandles;
 
     /// <summary>
     /// Replaces the time provider with a mocked instance. This allows to influence the used time in tests.
@@ -128,19 +136,6 @@ public MockFileSystem MockTime(Func<DateTime> dateTimeProvider)
         return this;
     }
 
-    private string FixPath(string path, bool checkCaps = false)
-    {
-        if (path == null)
-        {
-            throw new ArgumentNullException(nameof(path), StringResources.Manager.GetString("VALUE_CANNOT_BE_NULL"));
-        }
-
-        var pathSeparatorFixed = path.Replace(Path.AltDirectorySeparatorChar, Path.DirectorySeparatorChar);
-        var fullPath = Path.GetFullPath(pathSeparatorFixed);
-
-        return checkCaps ? GetPathWithCorrectDirectoryCapitalization(fullPath) : fullPath;
-    }
-
     //If C:\foo exists, ensures that trying to save a file to "C:\FOO\file.txt" instead saves it to "C:\foo\file.txt".
     private string GetPathWithCorrectDirectoryCapitalization(string fullPath)
     {
@@ -194,7 +189,7 @@ public MockFileData AdjustTimes(MockFileData fileData, TimeAdjustments timeAdjus
     /// <inheritdoc />
     public MockFileData GetFile(string path)
     {
-        path = FixPath(path).TrimSlashes();
+        path = pathVerifier.FixPath(path).TrimSlashes();
         return GetFileWithoutFixingPath(path);
     }
 
@@ -210,7 +205,9 @@ public MockDriveData GetDrive(string name)
 
     private void SetEntry(string path, MockFileData mockFile)
     {
-        path = FixPath(path, true).TrimSlashes();
+        path = GetPathWithCorrectDirectoryCapitalization(
+            pathVerifier.FixPath(path)
+        ).TrimSlashes();
 
         lock (files)
         {
@@ -232,7 +229,9 @@ private void SetEntry(string path, MockFileData mockFile)
     /// <inheritdoc />
     public void AddFile(string path, MockFileData mockFile, bool verifyAccess = true)
     {
-        var fixedPath = FixPath(path, true);
+        var fixedPath = GetPathWithCorrectDirectoryCapitalization(
+            pathVerifier.FixPath(path)
+        );
 
         mockFile ??= new MockFileData(string.Empty);
         var file = GetFile(fixedPath);
@@ -319,7 +318,9 @@ public MockFileData GetFile(IFileInfo path)
     /// <inheritdoc />
     public void AddDirectory(string path)
     {
-        var fixedPath = FixPath(path, true);
+        var fixedPath = GetPathWithCorrectDirectoryCapitalization(
+            pathVerifier.FixPath(path)
+        );
         var separator = Path.DirectorySeparatorChar.ToString();
 
         if (FileExists(fixedPath) && FileIsReadOnly(fixedPath))
@@ -408,8 +409,8 @@ public void AddDrive(string name, MockDriveData mockDrive)
     /// <inheritdoc />
     public void MoveDirectory(string sourcePath, string destPath)
     {
-        sourcePath = FixPath(sourcePath);
-        destPath = FixPath(destPath);
+        sourcePath = pathVerifier.FixPath(sourcePath);
+        destPath = pathVerifier.FixPath(destPath);
 
         var sourcePathSequence = sourcePath.Split(new[] { Path.DirectorySeparatorChar }, StringSplitOptions.RemoveEmptyEntries);
 
@@ -452,7 +453,7 @@ bool PathStartsWith(string path, string[] minMatch)
     /// <inheritdoc />
     public void RemoveFile(string path, bool verifyAccess = true)
     {
-        path = FixPath(path);
+        path = pathVerifier.FixPath(path);
 
         lock (files)
         {
@@ -473,7 +474,7 @@ public bool FileExists(string path)
             return false;
         }
 
-        path = FixPath(path).TrimSlashes();
+        path = pathVerifier.FixPath(path).TrimSlashes();
 
         lock (files)
         {

src/TestableIO.System.IO.Abstractions.TestingHelpers/PathVerifier.cs

@@ -183,4 +183,23 @@ public bool TryNormalizeDriveName(string name, out string result)
         result = name;
         return true;
     }
+
+    /// <summary>
+    /// Resolves and normalizes a path.
+    /// </summary>
+    public string FixPath(string path)
+    {
+        if (path == null)
+        {
+            throw new ArgumentNullException(nameof(path), StringResources.Manager.GetString("VALUE_CANNOT_BE_NULL"));
+        }
+
+        var pathSeparatorFixed = path.Replace(
+            _mockFileDataAccessor.Path.AltDirectorySeparatorChar,
+            _mockFileDataAccessor.Path.DirectorySeparatorChar
+        );
+        var fullPath = _mockFileDataAccessor.Path.GetFullPath(pathSeparatorFixed);
+
+        return fullPath;
+    }
 }

tests/TestableIO.System.IO.Abstractions.Api.Tests/Expected/TestableIO.System.IO.Abstractions.TestingHelpers_net472.txt

@@ -8,6 +8,7 @@ namespace System.IO.Abstractions.TestingHelpers
         System.Collections.Generic.IEnumerable<string> AllDrives { get; }
         System.Collections.Generic.IEnumerable<string> AllFiles { get; }
         System.Collections.Generic.IEnumerable<string> AllPaths { get; }
+        System.Collections.Concurrent.ConcurrentDictionary<string, System.Collections.Concurrent.ConcurrentDictionary<System.Guid, System.ValueTuple<System.IO.FileAccess, System.IO.FileShare>>> FileHandles { get; }
         System.IO.Abstractions.IFileSystem FileSystem { get; }
         System.IO.Abstractions.TestingHelpers.PathVerifier PathVerifier { get; }
         System.IO.Abstractions.TestingHelpers.StringOperations StringOperations { get; }
@@ -297,7 +298,7 @@ namespace System.IO.Abstractions.TestingHelpers
     [System.Serializable]
     public class MockFileStream : System.IO.Abstractions.FileSystemStream, System.IO.Abstractions.IFileSystemAclSupport
     {
-        public MockFileStream(System.IO.Abstractions.TestingHelpers.IMockFileDataAccessor mockFileDataAccessor, string path, System.IO.FileMode mode, System.IO.FileAccess access = 3, System.IO.FileOptions options = 0) { }
+        public MockFileStream(System.IO.Abstractions.TestingHelpers.IMockFileDataAccessor mockFileDataAccessor, string path, System.IO.FileMode mode, System.IO.FileAccess access = 3, System.IO.FileShare share = 1, System.IO.FileOptions options = 0) { }
         public override bool CanRead { get; }
         public override bool CanWrite { get; }
         public static System.IO.Abstractions.FileSystemStream Null { get; }
@@ -347,6 +348,7 @@ namespace System.IO.Abstractions.TestingHelpers
         public override System.IO.Abstractions.IDirectoryInfoFactory DirectoryInfo { get; }
         public override System.IO.Abstractions.IDriveInfoFactory DriveInfo { get; }
         public override System.IO.Abstractions.IFile File { get; }
+        public System.Collections.Concurrent.ConcurrentDictionary<string, System.Collections.Concurrent.ConcurrentDictionary<System.Guid, System.ValueTuple<System.IO.FileAccess, System.IO.FileShare>>> FileHandles { get; }
         public override System.IO.Abstractions.IFileInfoFactory FileInfo { get; }
         public override System.IO.Abstractions.IFileStreamFactory FileStream { get; }
         public System.IO.Abstractions.IFileSystem FileSystem { get; }
@@ -468,6 +470,7 @@ namespace System.IO.Abstractions.TestingHelpers
     {
         public PathVerifier(System.IO.Abstractions.TestingHelpers.IMockFileDataAccessor mockFileDataAccessor) { }
         public void CheckInvalidPathChars(string path, bool checkAdditional = false) { }
+        public string FixPath(string path) { }
         public bool HasIllegalCharacters(string path, bool checkAdditional) { }
         public void IsLegalAbsoluteOrRelative(string path, string paramName) { }
         public string NormalizeDriveName(string name) { }

tests/TestableIO.System.IO.Abstractions.Api.Tests/Expected/TestableIO.System.IO.Abstractions.TestingHelpers_net6.0.txt

@@ -8,6 +8,7 @@ namespace System.IO.Abstractions.TestingHelpers
         System.Collections.Generic.IEnumerable<string> AllDrives { get; }
         System.Collections.Generic.IEnumerable<string> AllFiles { get; }
         System.Collections.Generic.IEnumerable<string> AllPaths { get; }
+        System.Collections.Concurrent.ConcurrentDictionary<string, System.Collections.Concurrent.ConcurrentDictionary<System.Guid, System.ValueTuple<System.IO.FileAccess, System.IO.FileShare>>> FileHandles { get; }
         System.IO.Abstractions.IFileSystem FileSystem { get; }
         System.IO.Abstractions.TestingHelpers.PathVerifier PathVerifier { get; }
         System.IO.Abstractions.TestingHelpers.StringOperations StringOperations { get; }
@@ -346,7 +347,7 @@ namespace System.IO.Abstractions.TestingHelpers
     [System.Serializable]
     public class MockFileStream : System.IO.Abstractions.FileSystemStream, System.IO.Abstractions.IFileSystemAclSupport
     {
-        public MockFileStream(System.IO.Abstractions.TestingHelpers.IMockFileDataAccessor mockFileDataAccessor, string path, System.IO.FileMode mode, System.IO.FileAccess access = 3, System.IO.FileOptions options = 0) { }
+        public MockFileStream(System.IO.Abstractions.TestingHelpers.IMockFileDataAccessor mockFileDataAccessor, string path, System.IO.FileMode mode, System.IO.FileAccess access = 3, System.IO.FileShare share = 1, System.IO.FileOptions options = 0) { }
         public override bool CanRead { get; }
         public override bool CanWrite { get; }
         public static System.IO.Abstractions.FileSystemStream Null { get; }
@@ -402,6 +403,7 @@ namespace System.IO.Abstractions.TestingHelpers
         public override System.IO.Abstractions.IDirectoryInfoFactory DirectoryInfo { get; }
         public override System.IO.Abstractions.IDriveInfoFactory DriveInfo { get; }
         public override System.IO.Abstractions.IFile File { get; }
+        public System.Collections.Concurrent.ConcurrentDictionary<string, System.Collections.Concurrent.ConcurrentDictionary<System.Guid, System.ValueTuple<System.IO.FileAccess, System.IO.FileShare>>> FileHandles { get; }
         public override System.IO.Abstractions.IFileInfoFactory FileInfo { get; }
         public override System.IO.Abstractions.IFileStreamFactory FileStream { get; }
         public System.IO.Abstractions.IFileSystem FileSystem { get; }
@@ -524,6 +526,7 @@ namespace System.IO.Abstractions.TestingHelpers
     {
         public PathVerifier(System.IO.Abstractions.TestingHelpers.IMockFileDataAccessor mockFileDataAccessor) { }
         public void CheckInvalidPathChars(string path, bool checkAdditional = false) { }
+        public string FixPath(string path) { }
         public bool HasIllegalCharacters(string path, bool checkAdditional) { }
         public void IsLegalAbsoluteOrRelative(string path, string paramName) { }
         public string NormalizeDriveName(string name) { }

tests/TestableIO.System.IO.Abstractions.Api.Tests/Expected/TestableIO.System.IO.Abstractions.TestingHelpers_net8.0.txt

@@ -8,6 +8,7 @@ namespace System.IO.Abstractions.TestingHelpers
         System.Collections.Generic.IEnumerable<string> AllDrives { get; }
         System.Collections.Generic.IEnumerable<string> AllFiles { get; }
         System.Collections.Generic.IEnumerable<string> AllPaths { get; }
+        System.Collections.Concurrent.ConcurrentDictionary<string, System.Collections.Concurrent.ConcurrentDictionary<System.Guid, System.ValueTuple<System.IO.FileAccess, System.IO.FileShare>>> FileHandles { get; }
         System.IO.Abstractions.IFileSystem FileSystem { get; }
         System.IO.Abstractions.TestingHelpers.PathVerifier PathVerifier { get; }
         System.IO.Abstractions.TestingHelpers.StringOperations StringOperations { get; }
@@ -370,7 +371,7 @@ namespace System.IO.Abstractions.TestingHelpers
     [System.Serializable]
     public class MockFileStream : System.IO.Abstractions.FileSystemStream, System.IO.Abstractions.IFileSystemAclSupport
     {
-        public MockFileStream(System.IO.Abstractions.TestingHelpers.IMockFileDataAccessor mockFileDataAccessor, string path, System.IO.FileMode mode, System.IO.FileAccess access = 3, System.IO.FileOptions options = 0) { }
+        public MockFileStream(System.IO.Abstractions.TestingHelpers.IMockFileDataAccessor mockFileDataAccessor, string path, System.IO.FileMode mode, System.IO.FileAccess access = 3, System.IO.FileShare share = 1, System.IO.FileOptions options = 0) { }
         public override bool CanRead { get; }
         public override bool CanWrite { get; }
         public static System.IO.Abstractions.FileSystemStream Null { get; }
@@ -426,6 +427,7 @@ namespace System.IO.Abstractions.TestingHelpers
         public override System.IO.Abstractions.IDirectoryInfoFactory DirectoryInfo { get; }
         public override System.IO.Abstractions.IDriveInfoFactory DriveInfo { get; }
         public override System.IO.Abstractions.IFile File { get; }
+        public System.Collections.Concurrent.ConcurrentDictionary<string, System.Collections.Concurrent.ConcurrentDictionary<System.Guid, System.ValueTuple<System.IO.FileAccess, System.IO.FileShare>>> FileHandles { get; }
         public override System.IO.Abstractions.IFileInfoFactory FileInfo { get; }
         public override System.IO.Abstractions.IFileStreamFactory FileStream { get; }
         public System.IO.Abstractions.IFileSystem FileSystem { get; }
@@ -549,6 +551,7 @@ namespace System.IO.Abstractions.TestingHelpers
     {
         public PathVerifier(System.IO.Abstractions.TestingHelpers.IMockFileDataAccessor mockFileDataAccessor) { }
         public void CheckInvalidPathChars(string path, bool checkAdditional = false) { }
+        public string FixPath(string path) { }
         public bool HasIllegalCharacters(string path, bool checkAdditional) { }
         public void IsLegalAbsoluteOrRelative(string path, string paramName) { }
         public string NormalizeDriveName(string name) { }