CSHARP-600: Encapsulated the configurable delegate that determines whether a command can be sent to a secondary into a new class called CanCommandBeSentToSecondary.

rstam · rstam · commit 9eef88769525 · 2012-10-18T20:48:12.000-04:00
diff --git a/Driver/Core/MongoCursorEnumerator.cs b/Driver/Core/MongoCursorEnumerator.cs
@@ -28,6 +28,76 @@
 
 namespace MongoDB.Driver
 {
+    /// <summary>
+    /// Represents a container for the CanCommandBeSentToSecondary delegate.
+    /// </summary>
+    public static class CanCommandBeSentToSecondary
+    {
+        // private static fields
+        private static Func<BsonDocument, bool> __delegate = DefaultImplementation;
+        private static HashSet<string> __secondaryOkCommands = new HashSet<string>(StringComparer.InvariantCultureIgnoreCase)
+        {
+            "group",
+            "aggregate",
+            "collStats",
+            "dbStats",
+            "count",
+            "distinct",
+            "geoNear",
+            "geoSearch",
+            "geoWalk"
+        };
+
+        // public static properties
+        /// <summary>
+        /// Gets or sets the CanCommandBeSentToSecondary delegate.
+        /// </summary>
+        public static Func<BsonDocument, bool> Delegate
+        {
+            get { return __delegate; }
+            set
+            {
+                if (value == null)
+                {
+                    throw new ArgumentNullException("value");
+                }
+                __delegate = value;
+            }
+        }
+
+        // public static methods
+        /// <summary>
+        /// Default implementation of the CanCommandBeSentToSecondary delegate.
+        /// </summary>
+        /// <param name="document">The command.</param>
+        /// <returns>True if the command can be sent to a secondary member of a replica set.</returns>
+        public static bool DefaultImplementation(BsonDocument document)
+        {
+            if (document.ElementCount == 0)
+            {
+                return false;
+            }
+
+            var commandName = document.GetElement(0).Name;
+
+            if (__secondaryOkCommands.Contains(commandName))
+            {
+                return true;
+            }
+
+            if (commandName.Equals("mapreduce", StringComparison.InvariantCultureIgnoreCase))
+            {
+                BsonValue outValue;
+                if (document.TryGetValue("out", out outValue) && outValue.IsBsonDocument)
+                {
+                    return outValue.AsBsonDocument.Contains("inline");
+                }
+            }
+
+            return false;
+        }
+    }
+
     /// <summary>
     /// Reprsents an enumerator that fetches the results of a query sent to the server.
     /// </summary>
@@ -65,7 +135,7 @@ public MongoCursorEnumerator(MongoCursor<TDocument> cursor)
             if (_readPreference.ReadPreferenceMode != ReadPreferenceMode.Primary && _cursor.Collection.Name == "$cmd")
             {
                 var queryDocument = _cursor.Query.ToBsonDocument();
-                var isSecondaryOk = MongoDefaults.CanCommandBeSentToSecondary(queryDocument);
+                var isSecondaryOk = CanCommandBeSentToSecondary.Delegate(queryDocument);
                 if (!isSecondaryOk)
                 {
                     // if the command can't be sent to a secondary, then we use primary here
diff --git a/Driver/MongoDefaults.cs b/Driver/MongoDefaults.cs
@@ -30,7 +30,6 @@ public static class MongoDefaults
     {
         // private static fields
         private static bool __assignIdOnInsert = true;
-        private static Func<BsonDocument, bool> __canCommandBeSentToSecondary = CanCommandBeSendToSecondaryDefault;
         private static TimeSpan __connectTimeout = TimeSpan.FromSeconds(30);
         private static TimeSpan __maxConnectionIdleTime = TimeSpan.FromMinutes(10);
         private static TimeSpan __maxConnectionLifeTime = TimeSpan.FromMinutes(30);
@@ -39,18 +38,6 @@ public static class MongoDefaults
         private static int __minConnectionPoolSize = 0;
         private static SafeMode __safeMode = SafeMode.False;
         private static TimeSpan __secondaryAcceptableLatency = TimeSpan.FromMilliseconds(15);
-        private static HashSet<string> __secondaryOkCommands = new HashSet<string>(StringComparer.InvariantCultureIgnoreCase)
-        {
-            "group",
-            "aggregate",
-            "collStats",
-            "dbStats",
-            "count",
-            "distinct",
-            "geoNear",
-            "geoSearch",
-            "geoWalk"
-        };
         private static TimeSpan __socketTimeout = TimeSpan.Zero; // use operating system default (presumably infinite)
         private static int __tcpReceiveBufferSize = 64 * 1024; // 64KiB (note: larger than 2MiB fails on Mac using Mono)
         private static int __tcpSendBufferSize = 64 * 1024; // 64KiB (TODO: what is the optimum value for the buffers?)
@@ -68,24 +55,6 @@ public static bool AssignIdOnInsert
             set { __assignIdOnInsert = value; }
         }
 
-        /// <summary>
-        /// Gets or sets a delegate that informs the driver whether or not a command is allowed
-        /// to be sent to a secondary.
-        /// </summary>
-        public static Func<BsonDocument, bool> CanCommandBeSentToSecondary
-        {
-            get { return __canCommandBeSentToSecondary; }
-            set
-            {
-                if (value == null)
-                {
-                    throw new ArgumentNullException("value");
-                }
-
-                __canCommandBeSentToSecondary = value;
-            }
-        }
-
         /// <summary>
         /// Gets the actual wait queue size (either WaitQueueSize or WaitQueueMultiple x MaxConnectionPoolSize).
         /// </summary>
@@ -256,32 +225,5 @@ public static TimeSpan WaitQueueTimeout
             get { return __waitQueueTimeout; }
             set { __waitQueueTimeout = value; }
         }
-
-        // private static methods
-        private static bool CanCommandBeSendToSecondaryDefault(BsonDocument document)
-        {
-            if (document.ElementCount == 0)
-            {
-                return false;
-            }
-
-            var commandName = document.GetElement(0).Name;
-
-            if (__secondaryOkCommands.Contains(commandName))
-            {
-                return true;
-            }
-
-            if (commandName.Equals("mapreduce", StringComparison.InvariantCultureIgnoreCase))
-            {
-                BsonValue outValue;
-                if (document.TryGetValue("out", out outValue) && outValue.IsBsonDocument)
-                {
-                    return outValue.AsBsonDocument.Contains("inline");
-                }
-            }
-
-            return false;
-        }
     }
 }
diff --git a/DriverUnitTests/Core/CanCommandBeSentToSecondaryTests.cs b/DriverUnitTests/Core/CanCommandBeSentToSecondaryTests.cs
@@ -9,8 +9,24 @@
 namespace MongoDB.DriverUnitTests
 {
     [TestFixture]
-    public class MongoDefaultsTests
+    public class CanCommandBeSentToSecondaryTests
     {
+        [Test]
+        public void TestGetDelegate()
+        {
+            Func<BsonDocument, bool> defaultImplementation = CanCommandBeSentToSecondary.DefaultImplementation;
+            Assert.AreEqual(defaultImplementation, CanCommandBeSentToSecondary.Delegate);
+        }
+
+        [Test]
+        public void TestSetDelegate()
+        {
+            Func<BsonDocument, bool> func = doc => true;
+            CanCommandBeSentToSecondary.Delegate = func;
+            Assert.AreEqual(func, CanCommandBeSentToSecondary.Delegate);
+            CanCommandBeSentToSecondary.Delegate = CanCommandBeSentToSecondary.DefaultImplementation; // reset Delegate
+        }
+
         [TestCase("group", true)]
         [TestCase("aggregate", true)]
         [TestCase("geoSearch", true)]
@@ -21,7 +37,7 @@ public class MongoDefaultsTests
         public void TestCanSendCommandToSecondary(string command, bool expectedResult)
         {
             var doc = new BsonDocument(command, 1);
-            var result = MongoDefaults.CanCommandBeSentToSecondary(doc);
+            var result = CanCommandBeSentToSecondary.DefaultImplementation(doc);
 
             Assert.AreEqual(expectedResult, result);
         }
@@ -37,7 +53,7 @@ public void TestCanSendInlineMapReduceToSecondary()
                 { "out", new BsonDocument("inline", 1) }
             };
 
-            var result = MongoDefaults.CanCommandBeSentToSecondary(doc);
+            var result = CanCommandBeSentToSecondary.DefaultImplementation(doc);
 
             Assert.IsTrue(result);
         }
@@ -52,7 +68,7 @@ public void TestCannotSendNonInlineMapReduceToSecondary()
                 { "reduce", "return 1" }
             };
 
-            var result = MongoDefaults.CanCommandBeSentToSecondary(doc);
+            var result = CanCommandBeSentToSecondary.DefaultImplementation(doc);
 
             Assert.IsFalse(result);
         }
@@ -68,7 +84,7 @@ public void TestCannotSendNonInlineMapReduceToSecondary2()
                 { "out", new BsonDocument("merge", "funny") }
             };
 
-            var result = MongoDefaults.CanCommandBeSentToSecondary(doc);
+            var result = CanCommandBeSentToSecondary.DefaultImplementation(doc);
 
             Assert.IsFalse(result);
         }
diff --git a/DriverUnitTests/DriverUnitTests.csproj b/DriverUnitTests/DriverUnitTests.csproj
@@ -189,7 +189,7 @@
     <Compile Include="Linq\MongoQueryProviderTests.cs" />
     <Compile Include="Linq\SkipAndTakeTests.cs" />
     <Compile Include="Linq\Utils\BsonSerializationInfoHelperTests.cs" />
-    <Compile Include="MongoDefaultsTests.cs" />
+    <Compile Include="Core\CanCommandBeSentToSecondaryTests.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="Samples\MagicDiscriminatorTests.cs" />
   </ItemGroup>
