add filelocker

Pilz.IO/FileLocker.cs

@@ -0,0 +1,117 @@
+using System;
+using System.IO;
+
+namespace Pilz.IO
+{
+    public partial class FileLocker : IDisposable
+    {
+        private FileStream fsLock = null;
+
+        /// <summary>
+        /// Defines the file path to the file that should be locked.
+        /// </summary>
+        public string FilePath { get; private set; }
+        /// <summary>
+        /// Defines the file path to the lock file that is used to identify the file lock.
+        /// </summary>
+        public string LockFile { get; private set; }
+        /// <summary>
+        /// Defines if the file is locked privatly by this instance.
+        /// </summary>
+        public bool LockedPrivate { get; private set; } = false;
+
+        /// <summary>
+        /// Defines if the file is locked by an other instance/program/user.
+        /// </summary>
+        public bool LockedExternal
+        {
+            get
+            {
+                if (LockedPrivate)
+                    return false;
+                else
+                {
+                    string lockFile = FilePath + ".lock";
+                    bool isLocked = false;
+
+                    if (File.Exists(lockFile))
+                    {
+                        try
+                        {
+                            var fs = new FileStream(lockFile, FileMode.Open, FileAccess.Read);
+                            fs.Close();
+                        }
+                        catch (IOException ex)
+                        {
+                            isLocked = true;
+                        }
+                    }
+
+                    return isLocked;
+                }
+            }
+        }
+
+        /// <summary>
+        /// Generate a new instance of <see cref="FileLocker"/>.
+        /// </summary>
+        /// <param name="filePath">The file path to the file that should be locked.</param>
+        public FileLocker(string filePath) : this(filePath, true)
+        {
+        }
+
+        /// <summary>
+        /// Generate a new instance of <see cref="FileLocker"/>
+        /// </summary>
+        /// <param name="filePath">The file path to the file that should be locked.</param>
+        /// <param name="autoLock">Defines if the file should be locked automatically right after creating this instance.</param>
+        public FileLocker(string filePath, bool autoLock)
+        {
+            FilePath = filePath;
+            LockFile = filePath + ".lock";
+            if (autoLock) Lock();
+        }
+
+        /// <summary>
+        /// Locks the file, if not already locked privatly.
+        /// </summary>
+        public void Lock()
+        {
+            if (!LockedPrivate)
+            {
+                fsLock = new FileStream(LockFile, FileMode.Create, FileAccess.ReadWrite);
+                LockedPrivate = true;
+            }
+        }
+
+        /// <summary>
+        /// Unlocks the file, if locked privatly.
+        /// </summary>
+        public void Unlock()
+        {
+            if (LockedPrivate)
+            {
+                fsLock.Close();
+                fsLock.Dispose();
+                fsLock = null;
+                File.Delete(LockFile);
+                LockedPrivate = false;
+            }
+        }
+
+        #region IDisposable
+        private bool disposedValue;
+
+        protected virtual void Dispose(bool disposing)
+        {
+            if (!disposedValue)
+                Unlock();
+        }
+
+        public void Dispose()
+        {
+            Dispose(true);
+        }
+        #endregion
+    }
+}