Initial work towards optimizing FileService handlers

Fixes VSTS #853896 - [Feedback] Visual Studio freezes when i run mono
Fixes VSTS #902435 - Investigate performance issue with FileSystemWatcher

6 files changed, 156 insertions, 59 deletions

diff --git a/main/src/core/MonoDevelop.Core/CoreExtensions.cs b/main/src/core/MonoDevelop.Core/CoreExtensions.cs
index 3d90766d6b..0818ad2c72 100644
--- a/main/src/core/MonoDevelop.Core/CoreExtensions.cs
+++ b/main/src/core/MonoDevelop.Core/CoreExtensions.cs
@@ -26,6 +26,7 @@
 using System.Collections;
 using System.Collections.Generic;
 using System.Linq;
+using System.Reflection;
 using System.Threading.Tasks;
 using MonoDevelop.Core;
 
@@ -296,6 +297,82 @@ namespace System
 				}
 			}
 		}
+
+		internal static void TimeInvoke<T> (this EventHandler<T> events, object sender, T args)
+		{
+			var sw = new Diagnostics.Stopwatch ();
+			foreach (var ev in events.GetInvocationList ()) {
+				try {
+					sw.Restart ();
+					((EventHandler<T>)ev) (sender, args);
+					sw.Stop ();
+
+					lock (timings) {
+						if (!timings.TryGetValue (sender, out var timingPair)) {
+							timings [sender] = timingPair = new Dictionary<Reflection.MethodInfo, TimeSpan> ();
+						}
+
+						if (!timingPair.TryGetValue (ev.Method, out var previousTime))
+							previousTime = TimeSpan.Zero;
+
+						timingPair [ev.Method] = previousTime.Add (sw.Elapsed);
+					}
+				} catch (Exception ex) {
+					LoggingService.LogInternalError (ex);
+				}
+			}
+		}
+
+		static readonly Dictionary<object, Dictionary<MethodInfo, TimeSpan>> timings = new Dictionary<object, Dictionary<MethodInfo, TimeSpan>> ();
+
+		internal static void TimingsReport ()
+		{
+			foreach (var kvp in timings) {
+				var source = kvp.Key;
+				var values = kvp.Value;
+
+				Console.WriteLine ("Source {0}", source);
+				foreach (var timeReport in values.OrderByDescending (x => x.Value)) {
+					Console.WriteLine ("{0} - {1} {2}", timeReport.Value.ToString (), timeReport.Key.DeclaringType, timeReport.Key);
+				}
+			}
+		}
+
+		internal static void TimeInvoke (this EventHandler events, object sender, EventArgs args)
+		{
+			var sw = new Diagnostics.Stopwatch ();
+			foreach (var ev in events.GetInvocationList ()) {
+				try {
+					sw.Restart ();
+					((EventHandler)ev) (sender, args);
+					sw.Stop ();
+
+					lock (timings) {
+						if (!timings.TryGetValue (sender, out var timingPair)) {
+							timings [sender] = timingPair = new Dictionary<MethodInfo, TimeSpan> (MethodInfoEqualityComparer.Instance);
+						}
+
+						if (!timingPair.TryGetValue (ev.Method, out var previousTime))
+							previousTime = TimeSpan.Zero;
+
+						timingPair [ev.Method] = previousTime.Add (sw.Elapsed);
+					}
+				} catch (Exception ex) {
+					LoggingService.LogInternalError (ex);
+				}
+			}
+		}
+
+		sealed class MethodInfoEqualityComparer : IEqualityComparer<MethodInfo>
+		{
+			public static MethodInfoEqualityComparer Instance = new MethodInfoEqualityComparer ();
+			public bool Equals (MethodInfo x, MethodInfo y)
+				=> x.Name == y.Name
+				&& x.DeclaringType == y.DeclaringType;
+
+			public int GetHashCode (MethodInfo obj)
+				=> obj.Name.GetHashCode () ^ obj.DeclaringType.GetHashCode ();
+		}
 	}
 }
 
diff --git a/main/src/core/MonoDevelop.Core/MonoDevelop.Core/FileService.cs b/main/src/core/MonoDevelop.Core/MonoDevelop.Core/FileService.cs
index 81221d827b..cab986eacc 100644
--- a/main/src/core/MonoDevelop.Core/MonoDevelop.Core/FileService.cs
+++ b/main/src/core/MonoDevelop.Core/MonoDevelop.Core/FileService.cs
@@ -909,6 +909,8 @@ namespace MonoDevelop.Core
 
 	class EventQueue
 	{
+		static readonly EventQueue q = new EventQueue ();
+
 		static void RaiseSync (FileService.EventDataKind kind, FileEventArgs args)
 		{
 			var handler = FileService.GetHandler (kind);
@@ -918,14 +920,14 @@ namespace MonoDevelop.Core
 			// Ugly, but it saves us the problem of having to deal with generic event handlers without covariance.
 			if (args is FileCopyEventArgs copyArgs) {
 				if (handler is EventHandler<FileCopyEventArgs> copyHandler) {
-					copyHandler.Invoke (null, copyArgs);
+					copyHandler?.TimeInvoke (q, copyArgs);
 					return;
 				}
 				throw new InvalidOperationException ();
 			}
 
 			if (handler is EventHandler<FileEventArgs> fileHandler)
-				fileHandler.Invoke (null, args);
+				fileHandler?.TimeInvoke (q, args);
 			else
 				throw new InvalidOperationException ();
 		}
@@ -1345,17 +1347,17 @@ namespace MonoDevelop.Core
 
 		internal void OnFileCreated (FileEventArgs args)
 		{
-			FileCreated?.Invoke (this, Clone (args));
+			FileCreated?.TimeInvoke (this, Clone (args));
 		}
 
 		internal void OnFileRemoved (FileEventArgs args)
 		{
-			FileRemoved?.Invoke (this, Clone (args));
+			FileRemoved?.TimeInvoke (this, Clone (args));
 		}
 
 		internal void OnFileRenamed (FileCopyEventArgs args)
 		{
-			FileRenamed?.Invoke (this, Clone (args));
+			FileRenamed?.TimeInvoke (this, Clone (args));
 		}
 
 		static T Clone<T> (T args) where T : FileEventArgs, new()
diff --git a/main/src/core/MonoDevelop.Core/MonoDevelop.Projects.MSBuild/DefaultMSBuildEngine.cs b/main/src/core/MonoDevelop.Core/MonoDevelop.Projects.MSBuild/DefaultMSBuildEngine.cs
index 0cc36a1f0e..49f790ef94 100644
--- a/main/src/core/MonoDevelop.Core/MonoDevelop.Projects.MSBuild/DefaultMSBuildEngine.cs
+++ b/main/src/core/MonoDevelop.Core/MonoDevelop.Projects.MSBuild/DefaultMSBuildEngine.cs
@@ -1435,7 +1435,10 @@ namespace MonoDevelop.Projects.MSBuild
 		{
 			var pi = (ProjectInfo)projectInstance;
 			string filePath = MSBuildProjectService.FromMSBuildPath (pi.Project.BaseDirectory, include);
-			foreach (var g in pi.GlobIncludes.Where (g => g.Condition)) {
+			foreach (var g in pi.GlobIncludes) {
+				if (!g.Condition)
+					continue;
+
 				if (g.ExcludeRegex != null) {
 					if (g.ExcludeRegex.IsMatch (include))
 						continue;
diff --git a/main/src/core/MonoDevelop.Core/MonoDevelop.Projects.MSBuild/MSBuildProjectService.cs b/main/src/core/MonoDevelop.Core/MonoDevelop.Projects.MSBuild/MSBuildProjectService.cs
index d2874912c7..703bbcf97d 100644
--- a/main/src/core/MonoDevelop.Core/MonoDevelop.Projects.MSBuild/MSBuildProjectService.cs
+++ b/main/src/core/MonoDevelop.Core/MonoDevelop.Projects.MSBuild/MSBuildProjectService.cs
@@ -843,7 +843,7 @@ namespace MonoDevelop.Projects.MSBuild
 		{
 			int i = str.IndexOfAny (specialCharacters);
 			if (i != -1) {
-				var sb = new System.Text.StringBuilder ();
+				var sb = StringBuilderCache.Allocate ();
 				int start = 0;
 				while (i != -1) {
 					sb.Append (str, start, i - start);
@@ -855,7 +855,7 @@ namespace MonoDevelop.Projects.MSBuild
 				}
 				if (start < str.Length)
 					sb.Append (str, start, str.Length - start);
-				return sb.ToString ();
+				return StringBuilderCache.ReturnAndFree (sb);
 			}
 			return str;
 		}
diff --git a/main/src/core/MonoDevelop.Core/MonoDevelop.Projects/Project.cs b/main/src/core/MonoDevelop.Core/MonoDevelop.Projects/Project.cs
index 7caab35662..a7f140539b 100644
--- a/main/src/core/MonoDevelop.Core/MonoDevelop.Projects/Project.cs
+++ b/main/src/core/MonoDevelop.Core/MonoDevelop.Projects/Project.cs
@@ -48,6 +48,7 @@ using Microsoft.CodeAnalysis;
 using MonoDevelop.Core.Collections;
 using ICSharpCode.Decompiler.TypeSystem.Implementation;
 using System.Runtime.CompilerServices;
+using Microsoft.Extensions.ObjectPool;
 
 namespace MonoDevelop.Projects
 {
@@ -2406,19 +2407,23 @@ namespace MonoDevelop.Projects
 
 		internal virtual void OnFileChanged (object source, FileEventArgs e)
 		{
+			var args = new ProjectFileEventArgs ();
+
 			foreach (FileEventInfo fi in e) {
 				ProjectFile file = GetProjectFile (fi.FileName);
 				if (file != null) {
 					SetFastBuildCheckDirty ();
-					try {
-						NotifyFileChangedInProject (file);
-					} catch {
-						// Workaround Mono bug. The watcher seems to
-						// stop watching if an exception is thrown in
-						// the event handler
-					}
+					args.Add (new ProjectFileEventInfo (this, file));
 				}
 			}
+
+			try {
+				OnFileChangedInProject (args);
+			} catch {
+				// Workaround Mono bug. The watcher seems to
+				// stop watching if an exception is thrown in
+				// the event handler
+			}
 		}
 
 		protected override IEnumerable<FilePath> OnGetItemFiles (bool includeReferencedFiles)
@@ -4488,17 +4493,17 @@ namespace MonoDevelop.Projects
 		void OnFileRenamed (object sender, FileCopyEventArgs e)
 		{
 			foreach (FileEventInfo info in e) {
-				OnFileRenamed (info.SourceFile, info.TargetFile);
+				OnFileRenamed (info.SourceFile, info.TargetFile, info.IsDirectory);
 			}
 		}
 
-		void OnFileRenamed (FilePath sourceFile, FilePath targetFile)
+		void OnFileRenamed (FilePath sourceFile, FilePath targetFile, bool isDirectory)
 		{
 			if (Runtime.IsMainThread)
 				return;
 
 			try {
-				if (Directory.Exists (targetFile)) {
+				if (isDirectory) {
 					OnDirectoryRenamedExternally (sourceFile, targetFile);
 					return;
 				}
@@ -4508,7 +4513,7 @@ namespace MonoDevelop.Projects
 
 			Runtime.RunInMainThread (() => {
 				OnFileCreatedExternally (targetFile);
-				OnFileDeletedExternally (sourceFile);
+				OnFileDeletedExternally (sourceFile, isDirectory);
 			});
 		}
 
@@ -4518,25 +4523,30 @@ namespace MonoDevelop.Projects
 				return;
 
 			foreach (FileEventInfo info in e) {
-				OnFileCreated (info.FileName);
+				OnFileCreated (info.FileName, info.IsDirectory);
 			}
 		}
 
-		void OnFileCreated (FilePath filePath)
+		void OnFileCreated (FilePath filePath, bool isDirectory)
 		{
 			if (Runtime.IsMainThread)
 				return;
 
 			try {
-				if (Directory.Exists (filePath))
+				if (isDirectory)
 					return;
 
-				if (filePath.FileName == ".DS_Store")
-					return;
+				var fileName = ((string)filePath).AsSpan ();
+				fileName = fileName.Slice (fileName.LastIndexOf (Path.DirectorySeparatorChar) + 1);
 
-				// Ignore temporary files created when saving a file in the editor.
-				if (filePath.FileName.StartsWith (".#", StringComparison.OrdinalIgnoreCase))
-					return;
+				if (fileName[0] == '.') {
+					// Ignore temporary files created when saving a file in the editor.
+					if (fileName [1] == '#')
+						return;
+
+					if (fileName.SequenceEqual (".DS_Store".AsSpan ()))
+						return;
+				}
 
 				OnFileCreatedExternally (filePath);
 			} catch (Exception ex) {
@@ -4551,7 +4561,7 @@ namespace MonoDevelop.Projects
 
 			Runtime.RunInMainThread (() => {
 				foreach (FileEventInfo info in e) {
-					OnFileDeletedExternally (info.FileName);
+					OnFileDeletedExternally (info.FileName, info.IsDirectory);
 				}
 			});
 		}
@@ -4594,36 +4604,33 @@ namespace MonoDevelop.Projects
 		void OnDirectoryMovedOutOfProject (FilePath oldDirectory)
 		{
 			// Directory moved outside project directory. Remove files from project.
-			var projectFilesInDirectory = Files.GetFilesInPath (oldDirectory);
-			if (!projectFilesInDirectory.Any ())
-				return;
-
 			Runtime.RunInMainThread (() => {
-				foreach (ProjectFile file in projectFilesInDirectory)
-					Files.Remove (file);
+				Files.RemoveFilesInPath (oldDirectory);
 			});
 		}
 
+		static readonly ObjectPool<List<ProjectItem>> projectItemListPool = ObjectPool.Create<List<ProjectItem>> ();
+
 		void OnFileCreatedExternally (FilePath fileName)
 		{
 			if (sourceProject == null) {
-				// sometimes this method is called after disposing this class. 
+				// sometimes this method is called after disposing this class.
 				// (i.e. when quitting MD or creating a new project.)
 				LoggingService.LogWarning ("File created externally not processed. {0}", fileName);
 				return;
 			}
 
-			// Check file is inside the project directory. The file globs would exclude the file anyway
-			// if the relative path starts with "..\" but checking here avoids checking the file globs.
-			if (!fileName.IsChildPathOf (BaseDirectory))
-				return;
-
-			if (Files.Any (file => file.FilePath == fileName)) {
+			if (Files.GetFile (fileName) != null) {
 				// File exists in project. This can happen if the file was added
 				// in the IDE and not externally.
 				return;
 			}
 
+			// Check file is inside the project directory. The file globs would exclude the file anyway
+			// if the relative path starts with "..\" but checking here avoids checking the file globs.
+			if (!fileName.IsChildPathOf (BaseDirectory))
+				return;
+
 			string include = MSBuildProjectService.ToMSBuildPath (ItemDirectory, fileName);
 			var globItems = sourceProject.FindGlobItemsIncludingFile (include);
 			if (globItems == null) {
@@ -4633,34 +4640,37 @@ namespace MonoDevelop.Projects
 			}
 
 			if (!UseAdvancedGlobSupport)
-				globItems = globItems.Where (it => it.Metadata.GetProperties ().Count () == 0);
+				globItems = globItems.Where (it => !it.Metadata.GetProperties ().Any ());
 
+			var list = projectItemListPool.Get ();
 			foreach (var it in globItems) {
 				var eit = CreateFakeEvaluatedItem (sourceProject, it, include, null);
 				var pi = CreateProjectItem (eit);
 				pi.Read (this, eit);
-				if (Runtime.IsMainThread) {
-					Items.Add (pi);
-				} else {
-					Runtime.RunInMainThread (() => {
-						// Double check the file has not been added on the UI thread by the IDE.
-						if (!Files.Any (file => file.FilePath == fileName)) {
-							Items.Add (pi);
-						}
-					}).Ignore ();
-				}
+
+				list.Add (pi);
 			}
+
+			Runtime.RunInMainThread (() => {
+				// Double check the file has not been added on the UI thread by the IDE.
+				list.RemoveAll (x => Files.GetFile (fileName) != null);
+				Items.AddRange (list);
+				projectItemListPool.Return (list);
+			}).Ignore ();
 		}
 
-		void OnFileDeletedExternally (string fileName)
+		void OnFileDeletedExternally (string fileName, bool isDirectory)
 		{
-			if (File.Exists (fileName) || Directory.Exists (fileName)) {
-				// File has not been deleted. The delete event could have been due to
-				// the file being saved. Saving with TextFileUtility will result in
-				// FileService.SystemRename being called to move a temporary file
-				// to the file being saved which deletes and then creates the file.
+			// File has not been deleted. The delete event could have been due to
+			// the file being saved. Saving with TextFileUtility will result in
+			// FileService.SystemRename being called to move a temporary file
+			// to the file being saved which deletes and then creates the file.
+			bool notDeleted = isDirectory
+				? Directory.Exists (fileName)
+				: File.Exists (fileName);
+
+			if (notDeleted)
 				return;
-			}
 
 			Files.Remove (fileName);
 		}
diff --git a/main/src/core/MonoDevelop.Core/MonoDevelop.Projects/ProjectFileCollection.cs b/main/src/core/MonoDevelop.Core/MonoDevelop.Projects/ProjectFileCollection.cs
index e70d1e46ef..2e0e1d39b4 100644
--- a/main/src/core/MonoDevelop.Core/MonoDevelop.Projects/ProjectFileCollection.cs
+++ b/main/src/core/MonoDevelop.Core/MonoDevelop.Projects/ProjectFileCollection.cs
@@ -251,6 +251,11 @@ namespace MonoDevelop.Projects
 			}
 			return list.ToArray ();
 		}
+
+		internal void RemoveFilesInPath (FilePath path)
+		{
+			SetItems (this.Where (file => !file.FilePath.IsChildPathOf (path)));
+		}
 		
 		public void Remove (string fileName)
 		{