CSHARP-550: Support creating TTL collections with server 2.2.

Author: rstam

Driver/Builders/IndexOptionsBuilder.cs

@@ -101,6 +101,16 @@ public static IndexOptionsBuilder SetSparse(bool value)
             return new IndexOptionsBuilder().SetSparse(value);
         }
 
+        /// <summary>
+        /// Sets the time to live value.
+        /// </summary>
+        /// <param name="timeToLive">The time to live.</param>
+        /// <returns>The builder (so method calls can be chained).</returns>
+        public static IndexOptionsBuilder SetTimeToLive(TimeSpan timeToLive)
+        {
+            return new IndexOptionsBuilder().SetTimeToLive(timeToLive);
+        }
+
         /// <summary>
         /// Sets whether the index enforces unique values.
         /// </summary>
@@ -199,6 +209,17 @@ public IndexOptionsBuilder SetSparse(bool value)
             return this;
         }
 
+        /// <summary>
+        /// Sets the time to live value.
+        /// </summary>
+        /// <param name="timeToLive">The time to live.</param>
+        /// <returns>The builder (so method calls can be chained).</returns>
+        public IndexOptionsBuilder SetTimeToLive(TimeSpan timeToLive)
+        {
+            _document["expireAfterSeconds"] = (int)timeToLive.TotalSeconds;
+            return this;
+        }
+
         /// <summary>
         /// Sets whether the index enforces unique values.
         /// </summary>

Driver/Core/GetIndexesResult.cs

@@ -224,6 +224,25 @@ public BsonDocument RawDocument
             get { return _document; }
         }
 
+        /// <summary>
+        /// Gets the time to live value (or TimeSpan.MaxValue if index doesn't have a time to live value).
+        /// </summary>
+        public TimeSpan TimeToLive
+        {
+            get
+            {
+                BsonValue value;
+                if (_document.TryGetValue("expireAfterSeconds", out value))
+                {
+                    return TimeSpan.FromSeconds(value.ToInt32());
+                }
+                else
+                {
+                    return TimeSpan.MaxValue;
+                }
+            }
+        }
+
         /// <summary>
         /// Gets the version of the index.
         /// </summary>

DriverUnitTests/Builders/IndexOptionsBuilderTests.cs

@@ -68,6 +68,14 @@ public void TestSparse()
             Assert.AreEqual(expected, options.ToJson());
         }
 
+        [Test]
+        public void TestTimeToLive()
+        {
+            var options = IndexOptions.SetTimeToLive(TimeSpan.FromHours(1));
+            string expected = "{ \"expireAfterSeconds\" : 3600 }";
+            Assert.AreEqual(expected, options.ToJson());
+        }
+
         [Test]
         public void TestUnique()
         {

DriverUnitTests/Core/MongoCollectionTests.cs

@@ -276,6 +276,25 @@ public void TestDropIndex()
             Assert.AreEqual(1, _collection.GetIndexes().Count());
         }
 
+        [Test]
+        public void TestEnsureIndexTimeToLive()
+        {
+            if (_server.BuildInfo.Version >= new Version(2, 2))
+            {
+                _collection.DropAllIndexes();
+                Assert.AreEqual(1, _collection.GetIndexes().Count());
+
+                var keys = IndexKeys.Ascending("ts");
+                var options = IndexOptions.SetTimeToLive(TimeSpan.FromHours(1));
+                _collection.EnsureIndex(keys, options);
+
+                var indexes = _collection.GetIndexes();
+                Assert.AreEqual("_id_", indexes[0].Name);
+                Assert.AreEqual("ts_1", indexes[1].Name);
+                Assert.AreEqual(TimeSpan.FromHours(1), indexes[1].TimeToLive);
+            }
+        }
+
         [Test]
         public void TestExplain()
         {