Added AlwaysSerialize and NeverSerialize options

for properties.

.gitignore

@@ -2,6 +2,8 @@
 bin
 obj
 
+*.psess
+
 # mstest test results
 TestResults
 packages/

README.md

@@ -53,7 +53,17 @@ Features
 * Since configuration objects are plain objects, you can define instance
     methods, custom getters/setters, and more.
 * Validation can be performed on the final configuration object to ensure that
-  all of its values are valid.
+    all of its values are valid.
+* The configuration manager can mark a property that should be always
+    serialized or never serialized (`ConfigManager.AlwaysSerialize` and
+    `ConfigManager.NeverSerialize` respectively). A property marked as
+    `AlwaysSerialize` will be serialized regardless of whether or not it
+    changed. A property marked as `NeverSerialize` will never be serialized,
+    even if it's changed. The latter is useful for properties like passwords. 
+    The password may be stored in a protected configuration file that's only 
+    visible to the ConfigurationManager, but the source where changed 
+    properties are written may be world-readable. This way, changes to the
+    password within the application are not persisted.
 
 Existing Sources
 ================

SmartConf.Examples/Properties/AssemblyInfo.cs

@@ -32,5 +32,5 @@
 // You can specify all the values or you can default the Build and Revision Numbers 
 // by using the '*' as shown below:
 // [assembly: AssemblyVersion("1.0.*")]
-[assembly: AssemblyVersion("1.0.0.0")]
-[assembly: AssemblyFileVersion("1.0.0.0")]
+[assembly: AssemblyVersion("1.0.1.0")]
+[assembly: AssemblyFileVersion("1.0.1.0")]

SmartConf.UnitTest/Mocks/DummyConfigurationSource.cs

@@ -1,8 +1,9 @@
 using System.Collections.Generic;
+using System.Linq;
 
 namespace SmartConf.UnitTest.Mocks
 {
-    public class DummyConfigurationSource<T> : IConfigurationSource<T> where T : class
+    public class DummyConfigurationSource<T> : IConfigurationSource<T> where T : class, new()
     {
         public bool PrimarySource { get; set; }
 
@@ -36,7 +37,13 @@ public void Save(T obj)
 
         public void PartialSave(T obj, IEnumerable<string> propertyNames)
         {
-            SavedObject = obj;
+            var mrg = new T();
+            foreach (var prop in propertyNames
+                .Select(propertyName => typeof (T).GetProperty(propertyName)))
+            {
+                prop.SetValue(mrg, prop.GetValue(obj, null), null);
+            }
+            SavedObject = mrg;
         }
     }
 }

SmartConf.UnitTest/SmartConfUnitTest.cs

@@ -191,9 +191,10 @@ public void ChangedProperties_WhereOutHasUpdatedOccupation_ReturnsUpdatedOccupat
                 {
                     PrimarySource = true
                 },
-                new DummyConfigurationSource<Config>(source3));
-
-            configManager.Out.Occupation = "Cool";
+                new DummyConfigurationSource<Config>(source3))
+                {
+                    Out = {Occupation = "Cool"}
+                };
 
             var expected = new Dictionary<string, object>
                 {
@@ -235,8 +236,10 @@ public void SaveChanges_WherePrimarySourceIsNotLast_MergesPrimarySourceIntoOutpu
             // Act
             var newConf = new ConfigurationManager<Config>(
                 primarySource,
-                new DummyConfigurationSource<Config>(secondary));
-            newConf.Out.Age = 88;
+                new DummyConfigurationSource<Config>(secondary))
+                {
+                    Out = {Age = 88}
+                };
             newConf.SaveChanges();
 
             // Assert
@@ -306,5 +309,57 @@ public void Validation_WithMultipleSourcesWhereValidationIsFailingInFirstButOver
                 new ConfigValidator(), primarySource, secondarySource);
             // ReSharper restore ObjectCreationAsStatement
         }
+
+        [TestMethod]
+        public void AlwaysSerialize_WithUnchangedProperty_SerializesPropertyAnyway()
+        {
+            // Arrange
+            var secondary = new Config
+                {
+                    Age = 12,
+                    Name = "Timothy"
+                };
+
+            var primary = new Config();
+
+            var expected = new Config
+                {
+                    Name = "Timothy"
+                };
+
+            var configManager = new ConfigurationManager<Config>(
+                new DummyConfigurationSource<Config>(secondary),
+                new DummyConfigurationSource<Config>(primary));
+
+            configManager.AlwaysSerialize(t => t.Name);
+
+            var actualManager = new DummyConfigurationSource<Config>(new Config());
+            configManager.SaveChanges(actualManager);
+
+            Assert.IsTrue(new ConfigComparer().Equals(
+                expected, actualManager.SavedObject));
+        }
+
+        [TestMethod]
+        public void NeverSerialize_WithChangedProperty_DoesNotSerializeProperty()
+        {
+            var config = new Config
+                {
+                    Name = "Timothy"
+                };
+
+            var manager = new ConfigurationManager<Config>(
+                new DummyConfigurationSource<Config>(config));
+
+            manager.NeverSerialize(p => p.Occupation);
+
+            manager.Out.Occupation = "Top Secret";
+
+            var actualManager = new DummyConfigurationSource<Config>(new Config());
+            manager.SaveChanges(actualManager);
+
+            Assert.IsTrue(new ConfigComparer().Equals(
+                config, actualManager.SavedObject));
+        }
     }
 }

SmartConf.sln

@@ -29,4 +29,7 @@ Global
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
 	EndGlobalSection
+	GlobalSection(Performance) = preSolution
+		HasPerformanceSessions = true
+	EndGlobalSection
 EndGlobal

SmartConf/ConfigurationManager.cs

@@ -2,6 +2,7 @@
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
+using System.Linq.Expressions;
 using System.Reflection;
 using SmartConf.Sources;
 using SmartConf.Validation;
@@ -25,6 +26,10 @@ public class ConfigurationManager<T> where T : class, new()
 
         private readonly IConfigurationSource<T> _primarySource;
 
+        private readonly HashSet<string> _propertiesAlwaysSerialized;
+
+        private readonly HashSet<string> _propertiesNeverSerialized;
+
         /// <summary>
         /// This object contains the merged configuration settings.
         /// It will track all changes and save them out to a file
@@ -80,6 +85,9 @@ public ConfigurationManager(params IConfigurationSource<T>[] sources)
         /// <param name="sources"></param>
         public ConfigurationManager(IValidator<T> validator, params IConfigurationSource<T>[] sources)
         {
+            _propertiesAlwaysSerialized = new HashSet<string>();
+            _propertiesNeverSerialized = new HashSet<string>();
+
             var primarySources = sources.Where(s => s.PrimarySource);
             if (primarySources.Count() > 1)
             {
@@ -126,6 +134,38 @@ public ConfigurationManager(IValidator<T> validator, params IConfigurationSource
             EnableChangeTracking();
         }
 
+        /// <summary>
+        /// Tell the configuration manager to always serialize this property.
+        /// If the property is currently marked as "never serialize", that
+        /// status will be removed.
+        /// </summary>
+        /// <typeparam name="TProp"></typeparam>
+        /// <param name="prop"></param>
+        /// <returns></returns>
+        public ConfigurationManager<T> AlwaysSerialize<TProp>(Expression<Func<T, TProp>> prop)
+        {
+            var name = ((MemberExpression) prop.Body).Member.Name;
+            _propertiesAlwaysSerialized.Add(name);
+            _propertiesNeverSerialized.Remove(name);
+            return this;
+        }
+
+        /// <summary>
+        /// Tell the configuration manager to never serialize this property.
+        /// If the property is currently marked as "always serialize", that
+        /// status will be removed.
+        /// </summary>
+        /// <typeparam name="TProp"></typeparam>
+        /// <param name="prop"></param>
+        /// <returns></returns>
+        public ConfigurationManager<T> NeverSerialize<TProp>(Expression<Func<T, TProp>> prop)
+        {
+            var name = ((MemberExpression)prop.Body).Member.Name;
+            _propertiesNeverSerialized.Add(name);
+            _propertiesAlwaysSerialized.Remove(name);
+            return this;
+        }
+
         /// <summary>
         /// Return a configuration object composed of
         /// all sources except the primary source
@@ -180,9 +220,20 @@ public void SaveChanges(IConfigurationSource<T> source)
             var @base = CreateBaseConfig();
             var mrg = new T();
             mrg.MergeWith(_primarySource.Config);
-            mrg.MergeWith(Out, @base);
+            mrg.MergeWith(Out, defaultObject: @base);
+
+            // Copy over the values for all "always serialized" properties
+            foreach (var prop in _propertiesAlwaysSerialized
+                .Select(propName => typeof (T).GetProperty(propName)))
+            {
+                prop.SetValue(mrg, prop.GetValue(Out, null), null);
+            }
+
             source.PartialSave(mrg,
-                GetProperties(@base, Out, PropertyStatus.Changed).Select(p => p.Name));
+                GetProperties(@base, _primarySource.Config, PropertyStatus.Changed)
+                    .Select(p => p.Name)
+                    .Concat(_propertiesAlwaysSerialized)
+                    .Except(_propertiesNeverSerialized));
         }
 
         /// <summary>

SmartConf/Properties/AssemblyInfo.cs

@@ -32,5 +32,5 @@
 // You can specify all the values or you can default the Build and Revision Numbers 
 // by using the '*' as shown below:
 // [assembly: AssemblyVersion("1.0.*")]
-[assembly: AssemblyVersion("1.0.1.1")]
-[assembly: AssemblyFileVersion("1.0.1.1")]
+[assembly: AssemblyVersion("1.0.2.0")]
+[assembly: AssemblyFileVersion("1.0.2.0")]

SmartConf/SmartConf.nuspec

@@ -4,7 +4,7 @@
     <id>smartconf</id>
     <authors>Dan Nemec</authors>
     <owners>Dan Nemec</owners>
-    <version>1.0.2.0</version>
+    <version>1.0.3.0</version>
     <licenseUrl>http://www.opensource.org/licenses/mit-license.php</licenseUrl>
     <projectUrl>https://github.com/nemec/smartconf</projectUrl>
     <requireLicenseAcceptance>false</requireLicenseAcceptance>