Removed the thread that watches file changes

Author: Randall Flagg

src/LogExpert/Classes/Log/LogfileReader.cs

@@ -2,9 +2,7 @@
 using LogExpert.Entities;
 using LogExpert.Entities.EventArgs;
 using LogExpert.Interface;
-
 using NLog;
-
 using System;
 using System.Collections.Generic;
 using System.IO;
@@ -39,7 +37,6 @@ public class LogfileReader : IAutoLogLineColumnizerCallback
         private long _fileLength;
 
         private Task _garbageCollectorTask;
-        private Task _monitorTask;
         private readonly CancellationTokenSource cts = new();
 
         private bool _isDeleted;
@@ -51,7 +48,7 @@ public class LogfileReader : IAutoLogLineColumnizerCallback
 
         private ReaderWriterLock _lruCacheDictLock;
 
-
+        private FileSystemWatcher _watcher;
         private bool _shouldStop;
         private ILogFileInfo _watchedILogFileInfo;
 
@@ -571,28 +568,109 @@ public int GetRealLineNumForVirtualLineNum(int lineNum)
             return result;
         }
 
-        public void StartMonitoring()
+        public async Task StartMonitoring()
         {
-            _logger.Info("startMonitoring()");
-            _monitorTask = Task.Run(MonitorThreadProc, cts.Token);
+            _logger.Info("StartMonitoring() for file ${_watchedILogFileInfo.FullName}");
+
+            await Task.Run(() =>
+            {
+                _logger.Info("MonitorThreadProc() for file {0}", _watchedILogFileInfo.FullName);
+
+                long oldSize = 0;
+                try
+                {
+                    OnLoadingStarted(new LoadFileEventArgs(_fileName, 0, false, 0, false));
+                    ReadFiles();
+                    if (!_isDeleted)
+                    {
+                        oldSize = _fileLength;
+                        OnLoadingFinished();
+                    }
+                }
+                catch (Exception e)
+                {
+                    _logger.Error(e);
+                }
+            });
+
+            _watcher = new FileSystemWatcher
+            {
+                NotifyFilter = //NotifyFilters.Attributes
+                               //| NotifyFilters.CreationTime
+                               //| NotifyFilters.DirectoryName
+                               //|
+                                 NotifyFilters.FileName
+                                 //| NotifyFilters.LastAccess
+                                 | NotifyFilters.LastWrite
+                                 //| NotifyFilters.Security
+                                 | NotifyFilters.Size,
+
+                Path = Path.GetDirectoryName(_fileName) ?? throw new ArgumentException("Invalid file path"),
+                Filter = Path.GetFileName(_fileName), // Sets filter to the specific 
+                EnableRaisingEvents = true
+            };
+            _watcher.Changed += OnFileChanged;
+            _watcher.Created += OnCreated;
+            _watcher.Deleted += OnFileDeleted; 
+            _watcher.Renamed += OnFileRenamed;
+            _watcher.Error += OnFileError;
+
             _shouldStop = false;
         }
 
+        private void OnFileError(object sender, ErrorEventArgs e)
+        {
+            throw new NotImplementedException();
+        }
+
+        private void OnFileRenamed(object sender, RenamedEventArgs e)
+        {
+            throw new NotImplementedException();
+        }
+
+        private void OnCreated(object sender, FileSystemEventArgs e)
+        {
+            //TODO: This should be deleted before merge?
+            throw new NotImplementedException();
+        }
+
+        private void OnFileDeleted(object sender, FileSystemEventArgs e)
+        {
+            MonitoredFileNotFound();
+        }
+
+        private void OnFileChanged(object sender, FileSystemEventArgs e)
+        {
+            try
+            {
+                _watchedILogFileInfo.FileHasChanged();
+                _fileLength = _watchedILogFileInfo.Length;
+                FileChanged();
+            }
+            catch (FileNotFoundException ex)
+            {
+                MonitoredFileNotFound();
+            }
+            catch (Exception ex) { 
+                throw new NotImplementedException();
+            }
+        }
+
         public void StopMonitoring()
         {
             _logger.Info("stopMonitoring()");
             _shouldStop = true;
 
-            Thread.Sleep(_watchedILogFileInfo.PollInterval); // leave time for the threads to stop by themselves
-
-            if (_monitorTask != null)
+            if (_watcher != null)
             {
-                if (_monitorTask.Status == TaskStatus.Running) // if thread has not finished, abort it
-                {
-                    cts.Cancel();
-                }
+                _watcher.EnableRaisingEvents = false; // Stop watching
+                _watcher.Dispose(); // Release resources
+                _watcher = null; // Clear the reference
+
             }
 
+            Thread.Sleep(_watchedILogFileInfo.PollInterval); // leave time for the threads to stop by themselves
+
             if (_garbageCollectorTask.IsCanceled == false)
             {
                 if (_garbageCollectorTask.Status == TaskStatus.Running) // if thread has not finished, abort it
@@ -1464,74 +1542,6 @@ private LogBuffer GetFirstBufferForFileByLogBuffer(LogBuffer logBuffer)
             return resultBuffer;
         }
 
-        private void MonitorThreadProc()
-        {
-            Thread.CurrentThread.Name = "MonitorThread";
-            //IFileSystemPlugin fs = PluginRegistry.GetInstance().FindFileSystemForUri(this.watchedILogFileInfo.FullName);
-            _logger.Info("MonitorThreadProc() for file {0}", _watchedILogFileInfo.FullName);
-
-            long oldSize = 0;
-            try
-            {
-                OnLoadingStarted(new LoadFileEventArgs(_fileName, 0, false, 0, false));
-                ReadFiles();
-                if (!_isDeleted)
-                {
-                    oldSize = _fileLength;
-                    OnLoadingFinished();
-                }
-            }
-            catch (Exception e)
-            {
-                _logger.Error(e);
-            }
-
-            while (!_shouldStop)
-            {
-                try
-                {
-                    int pollInterval = _watchedILogFileInfo.PollInterval;
-                    //#if DEBUG
-                    //          if (_logger.IsDebug)
-                    //          {
-                    //            _logger.logDebug("Poll interval for " + this.fileName + ": " + pollInterval);
-                    //          }
-                    //#endif
-                    Thread.Sleep(pollInterval);
-                }
-                catch (Exception e)
-                {
-                    _logger.Error(e);
-                }
-
-                if (_shouldStop)
-                {
-                    return;
-                }
-
-                try
-                {
-                    if (_watchedILogFileInfo.FileHasChanged())
-                    {
-                        _fileLength = _watchedILogFileInfo.Length;
-                        if (_fileLength == -1)
-                        {
-                            MonitoredFileNotFound();
-                        }
-                        else
-                        {
-                            oldSize = _fileLength;
-                            FileChanged();
-                        }
-                    }
-                }
-                catch (FileNotFoundException)
-                {
-                    MonitoredFileNotFound();
-                }
-            }
-        }
-
         private void MonitoredFileNotFound()
         {
             long oldSize;