FEATURE-731: Backport of the title detection code

GreenshotJiraPlugin/Hooking/WindowsTitleMonitor.cs

@@ -0,0 +1,139 @@
+/*
+ * dapplo - building blocks for desktop applications
+ * Copyright (C) Dapplo 2015-2016
+ * 
+ * For more information see: http://dapplo.net/
+ * dapplo repositories are hosted on GitHub: https://github.com/dapplo
+ * 
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 1 of the License, or
+ * (at your option) any later version.
+ * 
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+using System;
+using GreenshotPlugin.Core;
+using GreenshotPlugin.UnmanagedHelpers;
+
+namespace GreenshotJiraPlugin.Hooking
+{
+	/// <summary>
+	/// Monitor all title changes
+	/// </summary>
+	public sealed class WindowsTitleMonitor : IDisposable
+	{
+		private WindowsEventHook _hook;
+		private readonly object _lockObject = new object();
+		// ReSharper disable once InconsistentNaming
+		private event TitleChangeEventDelegate _titleChangeEvent;
+
+		/// <summary>
+		/// Add / remove event handler to the title monitor
+		/// </summary>
+		public event TitleChangeEventDelegate TitleChangeEvent
+		{
+			add
+			{
+				lock (_lockObject)
+				{
+					if (_hook == null)
+					{
+						_hook = new WindowsEventHook();
+						_hook.Hook(WinEvent.EVENT_OBJECT_NAMECHANGE, WinEventHandler);
+					}
+					_titleChangeEvent += value;
+				}
+			}
+			remove
+			{
+				lock (_lockObject)
+				{
+					_titleChangeEvent -= value;
+					if (_titleChangeEvent == null || _titleChangeEvent.GetInvocationList().Length == 0)
+					{
+						if (_hook != null)
+						{
+							_hook.Dispose();
+							_hook = null;
+						}
+					}
+				}
+			}
+		}
+
+		/// <summary>
+		/// WinEventDelegate for the creation & destruction
+		/// </summary>
+		/// <param name="eventType"></param>
+		/// <param name="hWnd"></param>
+		/// <param name="idObject"></param>
+		/// <param name="idChild"></param>
+		/// <param name="dwEventThread"></param>
+		/// <param name="dwmsEventTime"></param>
+		private void WinEventHandler(WinEvent eventType, IntPtr hWnd, EventObjects idObject, int idChild, uint dwEventThread, uint dwmsEventTime)
+		{
+			if (hWnd == IntPtr.Zero || idObject != EventObjects.OBJID_WINDOW)
+			{
+				return;
+			}
+			if (eventType == WinEvent.EVENT_OBJECT_NAMECHANGE)
+			{
+				if (_titleChangeEvent != null)
+				{
+					string newTitle = new WindowDetails(hWnd).Text;
+					_titleChangeEvent(new TitleChangeEventArgs { HWnd = hWnd, Title = newTitle });
+				}
+			}
+		}
+
+		#region IDisposable Support
+
+		private bool _disposedValue; // To detect redundant calls
+
+		/// <summary>
+		/// Dispose the underlying hook
+		/// </summary>
+		public void Dispose(bool disposing)
+		{
+			if (_disposedValue)
+			{
+				return;
+			}
+			lock (_lockObject)
+			{
+				_hook?.Dispose();
+			}
+			_disposedValue = true;
+		}
+
+		/// <summary>
+		/// Make sure the finalizer disposes the underlying hook
+		/// </summary>
+		~WindowsTitleMonitor()
+		{
+			// Do not change this code. Put cleanup code in Dispose(bool disposing) above.
+			Dispose(false);
+		}
+
+		/// <summary>
+		/// Dispose the underlying hook
+		/// </summary>
+		public void Dispose()
+		{
+			// Do not change this code. Put cleanup code in Dispose(bool disposing) above.
+			Dispose(true);
+			GC.SuppressFinalize(this);
+		}
+
+		#endregion
+	}
+
+}