Imported Upstream version 5.4.0.167

Former-commit-id: 5624ac747d633e885131e8349322922b6a59baaa

external/api-doc-tools/mdoc/Mono.Documentation/MdocFile.cs

@@ -0,0 +1,83 @@
+//
+// MdocFile.cs: File utility methods
+//
+// Author:
+//   Jonathan Pryor  <jpryor@novell.com>
+//
+// Copyright (c) 2010 Novell, Inc. (http://www.novell.com)
+//
+// Permission is hereby granted, free of charge, to any person obtaining
+// a copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to
+// permit persons to whom the Software is furnished to do so, subject to
+// the following conditions:
+//
+// The above copyright notice and this permission notice shall be
+// included in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+//
+
+using System;
+using System.IO;
+
+namespace Mono.Documentation {
+
+	static class MdocFile {
+
+		public static void UpdateFile (string file, Action<string> creator)
+		{
+			if (!File.Exists (file) || file == "-") {
+				creator (file);
+				return;
+			}
+
+			string temp = Path.GetTempFileName ();
+			bool move = true;
+			try {
+				creator (temp);
+
+				using (var a = File.OpenRead (file))
+				using (var b = File.OpenRead (temp)) {
+					if (a.Length == b.Length)
+						move = !FileContentsIdentical (a, b);
+				}
+
+				if (move) {
+					File.Delete (file);
+					File.Move (temp, file);
+				}
+			}
+			finally {
+				if (!move && File.Exists (temp))
+					File.Delete (temp);
+			}
+		}
+
+		static bool FileContentsIdentical (Stream a, Stream b)
+		{
+			byte[] ba = new byte[4096];
+			byte[] bb = new byte[4096];
+			int ra, rb;
+
+			while ((ra = a.Read (ba, 0, ba.Length)) > 0 &&
+					(rb = b.Read (bb, 0, bb.Length)) > 0) {
+				if (ra != rb)
+					return false;
+				for (int i = 0; i < ra; ++i) {
+					if (ba [i] != bb [i])
+						return false;
+				}
+			}
+			return true;
+		}
+	}
+}