Fast file enumeration for Windows

src/System.IO.FileSystem/tests/Directory/EnumerableTests.cs

@@ -19,7 +19,21 @@ public void FileEnumeratorIsThreadSafe()
             for (int i = 0; i < 100; i++)
                 File.Create(Path.Combine(directory, GetTestFileName())).Dispose();
 
-            new ThreadSafeRepro().Execute(directory);
+            // We are really only trying to make sure we don't terminate the process.
+            // Throwing IOException at this point to try and flush out other problems
+            // like bad handles. Can narrow the throw if this isn't reliable.
+
+            try
+            {
+                new ThreadSafeRepro().Execute(directory);
+            }
+            catch (IOException)
+            {
+                throw;
+            }
+            catch (Exception)
+            {
+            }
         }
 
         class ThreadSafeRepro
@@ -46,17 +60,24 @@ void Work()
                         if (x != null)
                             Enumerate(x);
                     } while (!token.IsCancellationRequested);
-                    token.ThrowIfCancellationRequested();
                 }
 
-                new Task(Work, token).Start();
-                new Task(Work, token).Start();
-                for (int i = 0; i < 1000; i++)
+                Task taskOne = Task.Run(action: Work);
+                Task taskTwo = Task.Run(action: Work);
+
+                try
+                {
+                    for (int i = 0; i < 1000; i++)
+                    {
+                        _enumerator = Directory.EnumerateFiles(directory).GetEnumerator();
+                        Enumerate(_enumerator);
+                    }
+                }
+                finally
                 {
-                    _enumerator = Directory.EnumerateFiles(directory).GetEnumerator();
-                    Enumerate(_enumerator);
+                    source.Cancel();
+                    Task.WaitAll(taskOne, taskTwo);
                 }
-                source.Cancel();
             }
         }
     }

src/System.IO.FileSystem/tests/Directory/GetFileSystemEntries_str_str.cs

@@ -793,15 +793,19 @@ public void WindowsSearchPatternWithDoubleDots_Desktop()
         }
 
         [Fact]
-        [PlatformSpecific(TestPlatforms.Windows)]
         [SkipOnTargetFramework(TargetFrameworkMonikers.NetFramework)]
-        public void WindowsSearchPatternWithDoubleDots_Core()
+        public void SearchPatternWithDoubleDots_Core()
         {
             // Search pattern with double dots no longer throws ArgumentException
             string directory = Directory.CreateDirectory(GetTestFilePath()).FullName;
             Assert.Throws<DirectoryNotFoundException>(() => GetEntries(directory, Path.Combine("..ab ab.. .. abc..d", "abc..")));
             GetEntries(directory, "..");
             GetEntries(directory, @".." + Path.DirectorySeparatorChar);
+
+            Assert.Throws<DirectoryNotFoundException>(() => GetEntries(directory, Path.Combine("..ab ab.. .. abc..d", "abc", "..")));
+            GetEntries(directory, Path.Combine("..ab ab.. .. abc..d", "..", "abc"));
+            Assert.Throws<DirectoryNotFoundException>(() => GetEntries(directory, Path.Combine("..", "..ab ab.. .. abc..d", "abc")));
+            Assert.Throws<DirectoryNotFoundException>(() => GetEntries(directory, Path.Combine("..", "..ab ab.. .. abc..d", "abc") + Path.DirectorySeparatorChar));
         }
 
         private static char[] OldWildcards = new char[] { '*', '?' };
@@ -1009,22 +1013,6 @@ public void UnixSearchPatternDirectoryValidChar(string valid)
             }
         }
 
-        [Fact]
-        [PlatformSpecific(TestPlatforms.AnyUnix)]  // Search pattern with DoubleDots on Unix
-        public void UnixSearchPatternWithDoubleDots()
-        {
-            // search pattern is valid but directory doesn't exist
-            Assert.Throws<DirectoryNotFoundException>(() => GetEntries(TestDirectory, Path.Combine("..ab ab.. .. abc..d", "abc..")));
-
-            string directory = Directory.CreateDirectory(GetTestFilePath()).FullName;
-            GetEntries(directory, "..");
-            GetEntries(directory, @".." + Path.DirectorySeparatorChar);
-            GetEntries(directory, Path.Combine("..ab ab.. .. abc..d", "abc", ".."));
-            GetEntries(directory, Path.Combine("..ab ab.. .. abc..d", "..", "abc"));
-            GetEntries(directory, Path.Combine("..", "..ab ab.. .. abc..d", "abc"));
-            GetEntries(directory, Path.Combine("..", "..ab ab.. .. abc..d", "abc") + Path.DirectorySeparatorChar);
-        }
-
         #endregion
     }
 }