Convert RegexOptions to MongoRegexOption when translating expression for Linq

Allows more control over type of Regex match, e.g.
(x => Regex.IsMatch(x.Name, "^" + prefix, RegexOptions.IgnoreCase)

Also fixed bug where setting IgnoreCase would also set IgnorePatternWhitespace (MongoRegexOption flags overlapped)

Author: CaptainCodeman

source/MongoDB.Tests/IntegrationTests/Linq/MongoQueryProviderTests.cs

@@ -354,6 +354,20 @@ where Regex.IsMatch(p.FirstName, "Joe")
             Assert.AreEqual(new Document("FirstName", new MongoRegex("Joe")), queryObject.Query);
         }
 
+        [Test]
+        public void Regex_IsMatch_CaseInsensitive()
+        {
+            var people = from p in Collection.Linq()
+                         where Regex.IsMatch(p.FirstName, "Joe", RegexOptions.IgnoreCase)
+                         select p;
+
+            var queryObject = ((IMongoQueryable)people).GetQueryObject();
+            Assert.AreEqual(0, queryObject.Fields.Count);
+            Assert.AreEqual(0, queryObject.NumberToLimit);
+            Assert.AreEqual(0, queryObject.NumberToSkip);
+            Assert.AreEqual(new Document("FirstName", new MongoRegex("Joe", MongoRegexOption.IgnoreCase)), queryObject.Query);
+        }
+
         [Test]
         public void SingleEqualConstraint()
         {

source/MongoDB.Tests/IntegrationTests/Linq/MongoQueryTests.cs

@@ -370,6 +370,16 @@ where Regex.IsMatch(p.FirstName, "Joe")
             Assert.AreEqual(1, people.Count);
         }
 
+        [Test]
+        public void Regex_IsMatch_CaseInsensitive()
+        {
+            var people = (from p in Collection.Linq()
+                          where Regex.IsMatch(p.FirstName, "joe", RegexOptions.IgnoreCase)
+                          select p).ToList();
+
+            Assert.AreEqual(1, people.Count);
+        }
+
         [Test]
         public void Single()
         {

source/MongoDB.Tests/UnitTests/TestMongoRegex.cs

@@ -45,6 +45,14 @@ public void CanBeConstructedFromRegex()
             Assert.AreEqual("img", regex.RawOptions);
         }
 
+        [Test]
+        public void MongoRegexOptionFlagsAreIndependent()
+        {
+            var regex = new MongoRegex("expression", MongoRegexOption.IgnoreCase);
+            Assert.AreEqual("expression", regex.Expression);
+            Assert.AreEqual("i", regex.RawOptions);
+        }
+
         [Test]
         public void CanBeConstructedWithMongoRegexOption()
         {
@@ -53,6 +61,14 @@ public void CanBeConstructedWithMongoRegexOption()
             Assert.AreEqual("img", regex.RawOptions);
         }
 
+        [Test]
+        public void CanBeConstructedWithRegexOptions()
+        {
+            var regex = new MongoRegex("expression", RegexOptions.IgnoreCase | RegexOptions.Multiline);
+            Assert.AreEqual("expression", regex.Expression);
+            Assert.AreEqual("im", regex.RawOptions);
+        }
+
         [Test]
         public void CanReadOptions()
         {

source/MongoDB/Linq/Translators/DocumentFormatter.cs

@@ -225,7 +225,11 @@ protected override Expression VisitMethodCall(MethodCallExpression m)
                     else
                         throw new InvalidQueryException(string.Format("Only the static Regex.IsMatch is supported.", m.Method.Name));
 
-                    AddCondition(new MongoRegex(value));
+                    var regexOptions = RegexOptions.None;
+                    if (m.Arguments.Count > 2)
+                        regexOptions = EvaluateConstant<RegexOptions>(m.Arguments[2]);
+
+                    AddCondition(new MongoRegex(value, regexOptions));
                     PopConditionScope();
                     return m;
                 }

source/MongoDB/MongoRegex.cs

@@ -38,6 +38,16 @@ public MongoRegex(string expression, MongoRegexOption options)
             Options = options;
         }
 
+        /// <summary>
+        /// Initializes a new instance of the <see cref="MongoRegex"/> class.
+        /// </summary>
+        /// <param name="expression">The Regex expression.</param>
+        /// <param name="options">The Regex options.</param>
+        public MongoRegex(string expression, RegexOptions options)
+            : this(new Regex(expression, options))
+        {
+        }
+
         /// <summary>
         ///   Initializes a new instance of the <see cref = "MongoRegex" /> class.
         /// </summary>

source/MongoDB/MongoRegexOption.cs

@@ -25,6 +25,6 @@ public enum MongoRegexOption
         /// <summary>
         /// g - Eliminates unescaped white space from the pattern. 
         /// </summary>
-        IgnorePatternWhitespace = 3
+        IgnorePatternWhitespace = 4
     }
 }