FileSystemEntry.Unix: ensure properties are available when file is deleted.

src/libraries/System.IO.FileSystem/tests/Enumeration/AttributeTests.cs

@@ -9,106 +9,175 @@ namespace System.IO.Tests.Enumeration
 {
     public class AttributeTests : FileSystemTest
     {
-        private class DefaultFileAttributes : FileSystemEnumerator<string>
+        private class FileSystemEntryProperties
         {
-            public DefaultFileAttributes(string directory, EnumerationOptions options)
+            public string FileName { get; init; }
+            public FileAttributes Attributes { get; init; }
+            public DateTimeOffset CreationTimeUtc { get; init; }
+            public bool IsDirectory { get; init; }
+            public bool IsHidden { get; init; }
+            public DateTimeOffset LastAccessTimeUtc { get; init; }
+            public DateTimeOffset LastWriteTimeUtc { get; init; }
+            public long Length { get; init; }
+            public string Directory { get; init; }
+            public string FullPath { get; init; }
+            public string SpecifiedFullPath { get; init; }
+        }
+
+        private class GetPropertiesEnumerator : FileSystemEnumerator<FileSystemEntryProperties>
+        {
+            public GetPropertiesEnumerator(string directory, EnumerationOptions options)
                 : base(directory, options)
-            {
-            }
+            { }
 
             protected override bool ContinueOnError(int error)
             {
                 Assert.False(true, $"Should not have errored {error}");
                 return false;
             }
 
-            protected override bool ShouldIncludeEntry(ref FileSystemEntry entry)
-                => !entry.IsDirectory;
-
-            protected override string TransformEntry(ref FileSystemEntry entry)
+            protected override FileSystemEntryProperties TransformEntry(ref FileSystemEntry entry)
             {
-                string path = entry.ToFullPath();
-                File.Delete(path);
-
-                // Attributes require a stat call on Unix- ensure that we have the right attributes
-                // even if the returned file is deleted.
-                Assert.Equal(FileAttributes.Normal, entry.Attributes);
-                Assert.Equal(path, entry.ToFullPath());
-                return new string(entry.FileName);
+                return new FileSystemEntryProperties
+                {
+                    FileName = new string(entry.FileName),
+                    Attributes = entry.Attributes,
+                    CreationTimeUtc = entry.CreationTimeUtc,
+                    IsDirectory = entry.IsDirectory,
+                    IsHidden = entry.IsHidden,
+                    LastAccessTimeUtc = entry.LastAccessTimeUtc,
+                    LastWriteTimeUtc = entry.LastWriteTimeUtc,
+                    Length = entry.Length,
+                    Directory = new string(entry.Directory),
+                    FullPath = entry.ToFullPath(),
+                    SpecifiedFullPath = entry.ToSpecifiedFullPath()
+                };
             }
         }
 
-        [Fact]
-        public void FileAttributesAreExpected()
+        // The test is performed using two items with different properties (file/dir, file length)
+        // to check cached values from the previous entry don't leak into the non-existing entry.
+        [InlineData("dir1", "dir2")]
+        [InlineData("dir1", "file2")]
+        [InlineData("dir1", "link2")]
+        [InlineData("file1", "file2")]
+        [InlineData("file1", "dir2")]
+        [InlineData("file1", "link2")]
+        [InlineData("link1", "file2")]
+        [InlineData("link1", "dir2")]
+        [InlineData("link1", "link2")]
+        [Theory]
+        public void PropertiesWhenItemNoLongerExists(string item1, string item2)
         {
             DirectoryInfo testDirectory = Directory.CreateDirectory(GetTestFilePath());
-            FileInfo fileOne = new FileInfo(Path.Combine(testDirectory.FullName, GetTestFileName()));
-
-            fileOne.Create().Dispose();
-
-            if (PlatformDetection.IsWindows)
-            {
-                // Archive should always be set on a new file. Clear it and other expected flags to
-                // see that we get "Normal" as the default when enumerating.
-
-                Assert.True((fileOne.Attributes & FileAttributes.Archive) != 0);
-                fileOne.Attributes &= ~(FileAttributes.Archive | FileAttributes.NotContentIndexed);
-            }
-
-            using (var enumerator = new DefaultFileAttributes(testDirectory.FullName, new EnumerationOptions()))
-            {
-                Assert.True(enumerator.MoveNext());
-                Assert.Equal(fileOne.Name, enumerator.Current);
-                Assert.False(enumerator.MoveNext());
-            }
-        }
 
-        private class DefaultDirectoryAttributes : FileSystemEnumerator<string>
-        {
-            public DefaultDirectoryAttributes(string directory, EnumerationOptions options)
-                : base(directory, options)
-            {
-            }
+            FileSystemInfo item1Info = CreateItem(testDirectory, item1);
+            FileSystemInfo item2Info = CreateItem(testDirectory, item2);
 
-            protected override bool ShouldIncludeEntry(ref FileSystemEntry entry)
-                => entry.IsDirectory;
-
-            protected override bool ContinueOnError(int error)
+            using (var enumerator = new GetPropertiesEnumerator(testDirectory.FullName, new EnumerationOptions() { AttributesToSkip = 0 }))
             {
-                Assert.False(true, $"Should not have errored {error}");
-                return false;
+                // Move to the first item.
+                Assert.True(enumerator.MoveNext(), "Move first");
+                FileSystemEntryProperties entry = enumerator.Current;
+
+                Assert.True(entry.FileName == item1 || entry.FileName == item2, "Unexpected item");
+
+                // Delete both items.
+                DeleteItem(testDirectory, item1);
+                DeleteItem(testDirectory, item2);
+
+                // Move to the second item.
+                FileSystemInfo expected = entry.FileName == item1 ? item2Info : item1Info;
+                Assert.True(enumerator.MoveNext(), "Move second");
+                entry = enumerator.Current;
+
+                // Names and paths.
+                Assert.Equal(expected.Name, entry.FileName);
+                Assert.Equal(testDirectory.FullName, entry.Directory);
+                Assert.Equal(expected.FullName, entry.FullPath);
+                Assert.Equal(expected.FullName, entry.SpecifiedFullPath);
+
+                // Values determined during enumeration.
+                if (PlatformDetection.IsBrowser)
+                {
+                    // For Browser, all items are typed as DT_UNKNOWN.
+                    Assert.False(entry.IsDirectory);
+                    Assert.Equal(entry.FileName.StartsWith('.') ? FileAttributes.Hidden : FileAttributes.Normal, entry.Attributes);
+                }
+                else
+                {
+                    Assert.Equal(expected is DirectoryInfo, entry.IsDirectory);
+                    Assert.Equal(expected.Attributes, entry.Attributes);
+                }
+
+                if (PlatformDetection.IsWindows)
+                {
+                    Assert.Equal((expected.Attributes & FileAttributes.Hidden) != 0, entry.IsHidden);
+                    Assert.Equal(expected.CreationTimeUtc, entry.CreationTimeUtc);
+                    Assert.Equal(expected.LastAccessTimeUtc, entry.LastAccessTimeUtc);
+                    Assert.Equal(expected.LastWriteTimeUtc, entry.LastWriteTimeUtc);
+                    if (expected is FileInfo fileInfo)
+                    {
+                        Assert.Equal(fileInfo.Length, entry.Length);
+                    }
+                }
+                else
+                {
+                    // On Unix, these values were not determined during enumeration.
+                    // Because the file was deleted, the values can no longer be retrieved and sensible defaults are returned.
+                    Assert.Equal(entry.FileName.StartsWith('.'), entry.IsHidden);
+                    DateTimeOffset defaultTime = new DateTimeOffset(DateTime.FromFileTimeUtc(0));
+                    Assert.Equal(defaultTime, entry.CreationTimeUtc);
+                    Assert.Equal(defaultTime, entry.LastAccessTimeUtc);
+                    Assert.Equal(defaultTime, entry.LastWriteTimeUtc);
+                    Assert.Equal(0, entry.Length);
+                }
+
+                Assert.False(enumerator.MoveNext(), "Move final");
             }
 
-            protected override string TransformEntry(ref FileSystemEntry entry)
-            {
-                string path = entry.ToFullPath();
-                Directory.Delete(path);
-
-                // Attributes require a stat call on Unix- ensure that we have the right attributes
-                // even if the returned directory is deleted.
-                Assert.Equal(FileAttributes.Directory, entry.Attributes);
-                Assert.Equal(path, entry.ToFullPath());
-                return new string(entry.FileName);
-            }
-        }
-
-        [Fact]
-        public void DirectoryAttributesAreExpected()
-        {
-            DirectoryInfo testDirectory = Directory.CreateDirectory(GetTestFilePath());
-            DirectoryInfo subDirectory = Directory.CreateDirectory(Path.Combine(testDirectory.FullName, GetTestFileName()));
-
-            if (PlatformDetection.IsWindows)
+            static FileSystemInfo CreateItem(DirectoryInfo testDirectory, string item)
             {
-                // Clear possible extra flags to see that we get Directory
-                subDirectory.Attributes &= ~FileAttributes.NotContentIndexed;
+                string fullPath = Path.Combine(testDirectory.FullName, item);
+
+                // use the last char to have different lengths for different files.
+                Assert.True(item.EndsWith('1') || item.EndsWith('2'));
+                int length = (int)item[item.Length - 1];
+
+                if (item.StartsWith("dir"))
+                {
+                    Directory.CreateDirectory(fullPath);
+                    var info = new DirectoryInfo(fullPath);
+                    info.Refresh();
+                    return info;
+                }
+                else if (item.StartsWith("link"))
+                {
+                    File.CreateSymbolicLink(fullPath, new string('_', length));
+                    var info = new FileInfo(fullPath);
+                    info.Refresh();
+                    return info;
+                }
+                else
+                {
+                    File.WriteAllBytes(fullPath, new byte[length]);
+                    var info = new FileInfo(fullPath);
+                    info.Refresh();
+                    return info;
+                }
             }
 
-            using (var enumerator = new DefaultDirectoryAttributes(testDirectory.FullName, new EnumerationOptions()))
+            static void DeleteItem(DirectoryInfo testDirectory, string item)
             {
-                Assert.True(enumerator.MoveNext());
-                Assert.Equal(subDirectory.Name, enumerator.Current);
-                Assert.False(enumerator.MoveNext());
+                string fullPath = Path.Combine(testDirectory.FullName, item);
+                if (item.StartsWith("dir"))
+                {
+                    Directory.Delete(fullPath);
+                }
+                else
+                {
+                    File.Delete(fullPath);
+                }
             }
         }
 

src/libraries/System.Private.CoreLib/src/System/IO/Enumeration/FileSystemEntry.Unix.cs

@@ -10,7 +10,7 @@ namespace System.IO.Enumeration
     /// </summary>
     public unsafe ref partial struct FileSystemEntry
    {
-        internal Interop.Sys.DirectoryEntry _directoryEntry;
+        private Interop.Sys.DirectoryEntry _directoryEntry;
         private FileStatus _status;
         private Span<char> _pathBuffer;
         private ReadOnlySpan<char> _fullPath;
@@ -32,38 +32,34 @@ internal static FileAttributes Initialize(
             entry._pathBuffer = pathBuffer;
             entry._fullPath = ReadOnlySpan<char>.Empty;
             entry._fileName = ReadOnlySpan<char>.Empty;
-
             entry._status.InvalidateCaches();
+            entry._status.InitiallyDirectory = false;
 
             bool isDirectory = directoryEntry.InodeType == Interop.Sys.NodeType.DT_DIR;
             bool isSymlink   = directoryEntry.InodeType == Interop.Sys.NodeType.DT_LNK;
             bool isUnknown   = directoryEntry.InodeType == Interop.Sys.NodeType.DT_UNKNOWN;
 
-            // Some operating systems don't have the inode type in the dirent structure,
-            // so we use DT_UNKNOWN as a sentinel value. As such, check if the dirent is a
-            // symlink or a directory.
-            if (isUnknown)
+            if (isDirectory)
             {
-                isSymlink = entry.IsSymbolicLink;
-                // Need to fail silently in case we are enumerating
-                isDirectory = entry._status.IsDirectory(entry.FullPath, continueOnError: true);
+                entry._status.InitiallyDirectory = true;
             }
-            // Same idea as the directory check, just repeated for (and tweaked due to the
-            // nature of) symlinks.
-            // Whether we had the dirent structure or not, we treat a symlink to a directory as a directory,
-            // so we need to reflect that in our isDirectory variable.
             else if (isSymlink)
             {
-                // Need to fail silently in case we are enumerating
-                isDirectory = entry._status.IsDirectory(entry.FullPath, continueOnError: true);
+                entry._status.InitiallyDirectory = entry._status.IsDirectory(entry.FullPath, continueOnError: true);
+            }
+            else if (isUnknown)
+            {
+                entry._status.InitiallyDirectory = entry._status.IsDirectory(entry.FullPath, continueOnError: true);
+                if (entry._status.IsSymbolicLink(entry.FullPath, continueOnError: true))
+                {
+                    entry._directoryEntry.InodeType = Interop.Sys.NodeType.DT_LNK;
+                }
             }
-
-            entry._status.InitiallyDirectory = isDirectory;
 
             FileAttributes attributes = default;
-            if (isSymlink)
+            if (entry.IsSymbolicLink)
                 attributes |= FileAttributes.ReparsePoint;
-            if (isDirectory)
+            if (entry.IsDirectory)
                 attributes |= FileAttributes.Directory;
 
             return attributes;
@@ -119,15 +115,41 @@ public ReadOnlySpan<char> FileName
 
         // Windows never fails getting attributes, length, or time as that information comes back
         // with the native enumeration struct. As such we must not throw here.
-        public FileAttributes Attributes => _status.GetAttributes(FullPath, FileName);
+        public FileAttributes Attributes
+        {
+            get
+            {
+                FileAttributes attributes = _status.GetAttributes(FullPath, FileName, continueOnError: true);
+                if (attributes != (FileAttributes)(-1))
+                {
+                    return attributes;
+                }
+
+                // File was removed before we retrieved attributes.
+                // Return what we know.
+                attributes = default;
+
+                if (IsSymbolicLink)
+                    attributes |= FileAttributes.ReparsePoint;
+
+                if (IsDirectory)
+                    attributes |= FileAttributes.Directory;
+
+                if (FileStatus.IsNameHidden(FileName))
+                    attributes |= FileAttributes.Hidden;
+
+                return attributes != default ? attributes : FileAttributes.Normal;
+            }
+        }
         public long Length => _status.GetLength(FullPath, continueOnError: true);
         public DateTimeOffset CreationTimeUtc => _status.GetCreationTime(FullPath, continueOnError: true);
         public DateTimeOffset LastAccessTimeUtc => _status.GetLastAccessTime(FullPath, continueOnError: true);
         public DateTimeOffset LastWriteTimeUtc => _status.GetLastWriteTime(FullPath, continueOnError: true);
+        public bool IsHidden => _status.IsHidden(FullPath, FileName, continueOnError: true);
+        internal bool IsReadOnly => _status.IsReadOnly(FullPath, continueOnError: true);
+
         public bool IsDirectory => _status.InitiallyDirectory;
-        public bool IsHidden => _status.IsHidden(FullPath, FileName);
-        internal bool IsReadOnly => _status.IsReadOnly(FullPath);
-        internal bool IsSymbolicLink => _status.IsSymbolicLink(FullPath);
+        internal bool IsSymbolicLink => _directoryEntry.InodeType == Interop.Sys.NodeType.DT_LNK;
 
         public FileSystemInfo ToFileSystemInfo()
         {

src/libraries/System.Private.CoreLib/src/System/IO/FileStatus.Unix.cs

@@ -123,7 +123,7 @@ internal bool IsHidden(ReadOnlySpan<char> path, ReadOnlySpan<char> fileName, boo
             return HasHiddenFlag;
         }
 
-        internal bool IsNameHidden(ReadOnlySpan<char> fileName) => fileName.Length > 0 && fileName[0] == '.';
+        internal static bool IsNameHidden(ReadOnlySpan<char> fileName) => fileName.Length > 0 && fileName[0] == '.';
 
         // Returns true if the path points to a directory, or if the path is a symbolic link
         // that points to a directory
@@ -139,9 +139,9 @@ internal bool IsSymbolicLink(ReadOnlySpan<char> path, bool continueOnError = fal
             return HasSymbolicLinkFlag;
         }
 
-        internal FileAttributes GetAttributes(ReadOnlySpan<char> path, ReadOnlySpan<char> fileName)
+        internal FileAttributes GetAttributes(ReadOnlySpan<char> path, ReadOnlySpan<char> fileName, bool continueOnError = false)
         {
-            EnsureCachesInitialized(path);
+            EnsureCachesInitialized(path, continueOnError);
 
             if (!_exists)
                 return (FileAttributes)(-1);
@@ -326,8 +326,11 @@ private unsafe void SetAccessOrWriteTime(string path, DateTimeOffset time, bool
 
         internal long GetLength(ReadOnlySpan<char> path, bool continueOnError = false)
         {
+            // For symbolic links, on Windows, Length returns zero and not the target file size.
+            // On Unix, it returns the length of the path stored in the link.
+
             EnsureCachesInitialized(path, continueOnError);
-            return _fileCache.Size;
+            return IsFileCacheInitialized ? _fileCache.Size : 0;
         }
 
         // Tries to refresh the lstat cache (_fileCache).