Fixing bugs in OS X FileSystemWatcher to make all tests pass

Author: Jonathan Miller

src/Common/src/Interop/OSX/Interop.EventStream.cs

@@ -21,7 +21,7 @@ internal static partial class EventStream
         /// <summary>
         /// This constant specifies that we don't want historical file system events, only new ones
         /// </summary>
-        internal const ulong kFSEventStreamEventIdSinceNow = ulong.MaxValue;
+        internal const ulong kFSEventStreamEventIdSinceNow = 0xFFFFFFFFFFFFFFFF;
 
         /// <summary>
         /// Flags that describe what happened in the event that was received. These come from the FSEvents.h header file in the CoreServices framework.

src/Common/src/Interop/Unix/libc/Interop.sync.cs

@@ -0,0 +1,17 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System;
+using System.Runtime.InteropServices;
+
+internal static partial class Interop
+{
+    internal static partial class libc
+    {
+        /// <summary>
+        /// Flushes the OS-wide file buffer(s)
+        /// </summary>
+        [DllImport(Interop.Libraries.Libc)]
+        internal extern static void sync();
+    }
+}

src/System.IO.FileSystem.Watcher/src/System.IO.FileSystem.Watcher.csproj

@@ -84,6 +84,9 @@
     <Compile Include="$(CommonPath)\Interop\OSX\Interop.RunLoop.cs">
       <Link>Common\Interop\OSX\Interop.RunLoop.cs</Link>
     </Compile>
+    <Compile Include="$(CommonPath)\Interop\Unix\libc\Interop.sync.cs">
+      <Link>Common\Interop\Unix\Interop.sync.cs</Link>
+    </Compile>
     <Compile Include="$(CommonPath)\Microsoft\Win32\SafeHandles\SafeCreateHandle.OSX.cs">
       <Link>Common\Microsoft\Win32\SafeHandles\SafeCreateHandle.OSX.cs</Link>
     </Compile>

src/System.IO.FileSystem.Watcher/src/System/IO/FileSystemWatcher.OSX.cs

@@ -456,7 +456,7 @@ private void NotifyFileSystemEventArgs(WatcherChangeTypes changeType, string nam
                     break;
             }
 
-            if (handler != null && MatchPattern(name))
+            if (handler != null && MatchPattern(string.IsNullOrEmpty(name) ? _directory : name))
             {
                 handler(this, new FileSystemEventArgs(changeType, _directory, name));
             }

src/System.IO.FileSystem.Watcher/src/System/IO/FileSystemWatcher.cs

@@ -75,4 +75,22 @@ public static void FileSystemWatcher_Changed_Negative()
             Utility.ExpectNoEvent(eventOccured, "changed");
         }
     }
+
+    [Fact, ActiveIssue(2279)]
+    public static void FileSystemWatcher_ChangeWatchedFolder()
+    {
+        using (var dir = Utility.CreateTestDirectory())
+        using (var watcher = new FileSystemWatcher())
+        {
+            watcher.Path = Path.GetFullPath(dir.Path);
+            watcher.Filter = "*";
+            AutoResetEvent eventOccured = Utility.WatchForEvents(watcher, WatcherChangeTypes.Changed);
+
+            watcher.EnableRaisingEvents = true;
+
+            Directory.SetLastAccessTime(watcher.Path, DateTime.Now);
+
+            Utility.ExpectEvent(eventOccured, "changed");
+        }
+    }
 }

src/System.IO.FileSystem.Watcher/tests/FileSystemWatcher.Changed.cs

@@ -178,7 +178,14 @@ public DateTimeOffset CreationTime
                         DateTimeOffset.FromUnixTimeSeconds(_fileinfo.btime) :
                         default(DateTimeOffset);
                 }
-                set { } // Not supported
+                set 
+                {
+                    // The ctime in Unix can be interpreted differently by different formats so there isn't
+                    // a reliable way to set this; however, we can't just do nothing since the FileSystemWatcher
+                    // specifically looks for this call to make a Metatdata Change, so we should set the 
+                    // LastAccessTime of the file to cause the metadata change we need.
+                    LastAccessTime = LastAccessTime;
+                }
             }
 
             public DateTimeOffset LastAccessTime