From d5dd42f127b043d725ad30ee1c13060d4c5db4de Mon Sep 17 00:00:00 2001
From: Rob Reynolds <ferventcoder@gmail.com>
Date: Thu, 17 Sep 2015 22:10:46 -0500
Subject: [PATCH] (GH-364) Only update the config if changed

Do not try to write to the config file unless something has changed.
---
 .../infrastructure.app/services/FilesServiceSpecs.cs  |  4 +++-
 src/chocolatey/infrastructure/services/XmlService.cs  | 11 +++++++++--
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/src/chocolatey.tests.integration/infrastructure.app/services/FilesServiceSpecs.cs b/src/chocolatey.tests.integration/infrastructure.app/services/FilesServiceSpecs.cs
index b5cc3278df..18af879850 100644
--- a/src/chocolatey.tests.integration/infrastructure.app/services/FilesServiceSpecs.cs
+++ b/src/chocolatey.tests.integration/infrastructure.app/services/FilesServiceSpecs.cs
@@ -35,10 +35,12 @@ public abstract class FilesServiceSpecsBase : TinySpec
         {
             protected FilesService Service;
             protected IFileSystem FileSystem = new DotNetFileSystem();
+            protected IHashProvider HashProvider;
 
             public override void Context()
             {
-                Service = new FilesService(new XmlService(FileSystem), FileSystem, new CrytpoHashProvider(FileSystem, CryptoHashProviderType.Md5));
+                HashProvider = new CrytpoHashProvider(FileSystem, CryptoHashProviderType.Md5);
+                Service = new FilesService(new XmlService(FileSystem, HashProvider), FileSystem, new CrytpoHashProvider(FileSystem, CryptoHashProviderType.Md5));
             }
         }
 
diff --git a/src/chocolatey/infrastructure/services/XmlService.cs b/src/chocolatey/infrastructure/services/XmlService.cs
index 18bcd8d577..c56f0297e6 100644
--- a/src/chocolatey/infrastructure/services/XmlService.cs
+++ b/src/chocolatey/infrastructure/services/XmlService.cs
@@ -19,6 +19,7 @@ namespace chocolatey.infrastructure.services
     using System.Text;
     using System.Xml;
     using System.Xml.Serialization;
+    using cryptography;
     using filesystem;
     using tolerance;
 
@@ -28,10 +29,12 @@ namespace chocolatey.infrastructure.services
     public sealed class XmlService : IXmlService
     {
         private readonly IFileSystem _fileSystem;
+        private readonly IHashProvider _hashProvider;
 
-        public XmlService(IFileSystem fileSystem)
+        public XmlService(IFileSystem fileSystem, IHashProvider hashProvider)
         {
             _fileSystem = fileSystem;
+            _hashProvider = hashProvider;
         }
 
         public XmlType deserialize<XmlType>(string xmlFilePath)
@@ -74,7 +77,11 @@ public void serialize<XmlType>(XmlType xmlType, string xmlFilePath)
                     textWriter.Close();
                     textWriter.Dispose();
 
-                    _fileSystem.copy_file(xmlUpdateFilePath, xmlFilePath, overwriteExisting: true);
+                    if (!_hashProvider.hash_file(xmlFilePath).is_equal_to(_hashProvider.hash_file(xmlUpdateFilePath)))
+                    {
+                        _fileSystem.copy_file(xmlUpdateFilePath, xmlFilePath, overwriteExisting: true);
+                    }
+
                     _fileSystem.delete_file(xmlUpdateFilePath);
                 },
                 "Error serializing type {0}".format_with(typeof(XmlType)),