Merge pull request #1379 from microsoft/main

Merge 'main' into 'release_mdd'

Author: WardenGnaw

src/DebugEngineHost/HostNatvisProject.cs

@@ -104,7 +104,7 @@ public static IDisposable WatchNatvisOptionSetting(HostConfigurationStore config
                             IDisposable disposable = rmw.CurrentMonitor;
 
                             // Watch NatvisDiagnostic section
-                            rmw = new RegisterMonitorWrapper(CreateAndStartNatvisDiagnosticMonitor(natvisDiagnosticSection, natvisLogger));
+                            rmw = new RegisterMonitorWrapper(CreateAndStartNatvisDiagnosticMonitor(checkForSection, natvisLogger));
 
                             disposable.Dispose();
                         }

src/DebugEngineHost/RegistryMonitor.cs

@@ -47,14 +47,15 @@ private static extern int RegNotifyChangeKeyValue(SafeRegistryHandle hKey, bool
 
         #endregion
 
-        private HostConfigurationSection _section;
+        private readonly HostConfigurationSection _section;
         private readonly bool _watchSubtree;
 
-        // Set when registry value is changed
-        private AutoResetEvent m_changeEvent;
-
         // Set when monitoring is stopped
-        private AutoResetEvent m_stoppedEvent;
+        private AutoResetEvent _stoppedEvent;
+
+        // Members to handle multiple stop calls.
+        private bool _isStopped = false;
+        private readonly object _stopLock = new object();
 
         /// <summary>
         /// Occurs when the specified registry key has changed.
@@ -80,9 +81,13 @@ public void Start()
 
         public void Stop()
         {
-            if (m_stoppedEvent != null)
+            lock (_stopLock)
             {
-                m_stoppedEvent.Set();
+                if (!_isStopped)
+                {
+                    _stoppedEvent?.Set();
+                    _isStopped = true;
+                }
             }
         }
 
@@ -93,53 +98,52 @@ private void Monitor()
             bool stopped = false;
             try
             {
-                m_stoppedEvent = new AutoResetEvent(false);
-                m_changeEvent = new AutoResetEvent(false);
-
-                IntPtr handle = m_changeEvent.SafeWaitHandle.DangerousGetHandle();
-
-                int errorCode = RegNotifyChangeKeyValue(_section.Handle, _watchSubtree, RegChangeNotifyFilter.REG_NOTIFY_CHANGE_NAME | RegChangeNotifyFilter.REG_NOTIFY_CHANGE_LAST_SET, handle, true);
-                if (errorCode != 0) // 0 is ERROR_SUCCESS
-                {
-                    _nativsLogger?.WriteLine(LogLevel.Error, Resource.Error_WatchRegistry, errorCode);
-                }
-                else
+                _stoppedEvent = new AutoResetEvent(false);
+                using (AutoResetEvent registryChangedEvent = new AutoResetEvent(false))
                 {
-                    while (!stopped)
-                    {
-                        int waitResult = WaitHandle.WaitAny(new WaitHandle[] { m_stoppedEvent, m_changeEvent });
+                    IntPtr handle = registryChangedEvent.SafeWaitHandle.DangerousGetHandle();
 
-                        if (waitResult == 0)
-                        {
-                            stopped = true;
-                        }
-                        else
+                    int errorCode = RegNotifyChangeKeyValue(_section.Handle, _watchSubtree, RegChangeNotifyFilter.REG_NOTIFY_CHANGE_NAME | RegChangeNotifyFilter.REG_NOTIFY_CHANGE_LAST_SET, handle, true);
+                    if (errorCode != 0) // 0 is ERROR_SUCCESS
+                    {
+                        _nativsLogger?.WriteLine(LogLevel.Error, Resource.Error_WatchRegistry, errorCode);
+                    }
+                    else
+                    {
+                        while (!stopped)
                         {
-                            errorCode = RegNotifyChangeKeyValue(_section.Handle, _watchSubtree, RegChangeNotifyFilter.REG_NOTIFY_CHANGE_NAME | RegChangeNotifyFilter.REG_NOTIFY_CHANGE_LAST_SET, handle, true);
-                            if (errorCode != 0) // 0 is ERROR_SUCCESS
+                            int waitResult = WaitHandle.WaitAny(new WaitHandle[] { _stoppedEvent, registryChangedEvent });
+
+                            if (waitResult == 0)
                             {
-                                _nativsLogger?.WriteLine(LogLevel.Error, Resource.Error_WatchRegistry, errorCode);
-                                break;
+                                stopped = true;
+                            }
+                            else
+                            {
+                                errorCode = RegNotifyChangeKeyValue(_section.Handle, _watchSubtree, RegChangeNotifyFilter.REG_NOTIFY_CHANGE_NAME | RegChangeNotifyFilter.REG_NOTIFY_CHANGE_LAST_SET, handle, true);
+                                if (errorCode != 0) // 0 is ERROR_SUCCESS
+                                {
+                                    _nativsLogger?.WriteLine(LogLevel.Error, Resource.Error_WatchRegistry, errorCode);
+                                    break;
+                                }
+                                RegChanged?.Invoke(this, null);
                             }
-                            RegChanged?.Invoke(this, null);
                         }
                     }
                 }
             }
             finally
             {
-                _section.Dispose();
-                m_stoppedEvent?.Dispose();
-                m_changeEvent?.Dispose();
+                _stoppedEvent.Dispose();
+                _stoppedEvent = null;
 
-                m_stoppedEvent = null;
-                m_changeEvent = null;
+                _section.Dispose();
             }
         }
 
         public void Dispose()
         {
-            m_stoppedEvent?.Dispose();
+            Stop(); // Stopping the monitor will dispose of the AutoResetEvent and HostConfigurationSection
         }
     }
 }