Add NotepadWindow utility (ideal for use with SelfLog)

Author: augustoproiete

src/Serilog.Sinks.Notepad/Sinks/Notepad/NotepadWindow.cs

@@ -0,0 +1,67 @@
+// Copyright 2020 C. Augusto Proiete & Contributors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+using System;
+using Serilog.Sinks.Notepad.Interop;
+
+namespace Serilog.Sinks.Notepad
+{
+    /// <summary>
+    /// Writes messages directly to the most recent `notepad.exe` process
+    /// </summary>
+    /// <example>
+    /// Capture internal errors from Serilog sinks via <see cref="Serilog.Debugging.SelfLog"/>:
+    /// <code>
+    /// Serilog.Debugging.SelfLog.Enable(s => NotepadWindow.WriteLine($"Internal Error with Serilog: {s}"));
+    /// </code>
+    /// </example>
+    public static class NotepadWindow
+    {
+        private static readonly Lazy<NotepadTextWriter> _notepadWindow =
+            new Lazy<NotepadTextWriter>(() => new NotepadTextWriter());
+
+        /// <summary>
+        /// Writes a string to the most recent Notepad window open.
+        /// If the given string is null, nothing is written to the text stream.
+        /// </summary>
+        /// <param name="value">The string to be written</param>
+        public static void Write(string value)
+        {
+            var notepadWindow = _notepadWindow.Value;
+            notepadWindow.Write(value);
+            notepadWindow.Flush();
+        }
+
+        /// <summary>
+        /// Writes a line terminator to the most recent Notepad window open.
+        /// </summary>
+        public static void WriteLine()
+        {
+            var notepadWindow = _notepadWindow.Value;
+            notepadWindow.WriteLine();
+            notepadWindow.Flush();
+        }
+
+        /// <summary>
+        /// Writes a line terminator to the most recent Notepad window open.
+        /// </summary>
+        /// <param name="value">The string to be written</param>
+        public static void WriteLine(string value)
+        {
+            var notepadWindow = _notepadWindow.Value;
+            notepadWindow.WriteLine(value);
+            notepadWindow.Flush();
+        }
+    }
+}