CSHARP-5552: Add support for $convert in LINQ

src/MongoDB.Driver/Core/Misc/Feature.cs

@@ -44,6 +44,8 @@ public class Feature
         private static readonly Feature __clientBulkWrite = new Feature("ClientBulkWrite", WireVersion.Server80);
         private static readonly Feature __clientSideEncryption = new Feature("ClientSideEncryption", WireVersion.Server42);
         private static readonly Feature __clusteredIndexes = new Feature("ClusteredIndexes", WireVersion.Server53);
+        private static readonly Feature __convertOperatorBinDataToFromNumeric = new Feature("ConvertOperatorBinDataToFromNumeric", WireVersion.Server81);
+        private static readonly Feature __convertOperatorBinDataToFromString= new Feature("ConvertOperatorBinDataToFromString", WireVersion.Server80);
         private static readonly Feature __createIndexCommitQuorum = new Feature("CreateIndexCommitQuorum", WireVersion.Server44);
         private static readonly Feature __createIndexesUsingInsertOperations = new Feature("CreateIndexesUsingInsertOperations", WireVersion.Zero, WireVersion.Server42);
         private static readonly Feature __csfleRangeAlgorithm = new Feature("CsfleRangeAlgorithm", WireVersion.Server62);
@@ -193,6 +195,16 @@ public class Feature
         /// </summary>
         public static Feature ClusteredIndexes => __clusteredIndexes;
 
+        /// <summary>
+        /// Gets the conversion of binary data to/from numeric types feature.
+        /// </summary>
+        public static Feature ConvertOperatorBinDataToFromNumeric => __convertOperatorBinDataToFromNumeric;
+
+        /// <summary>
+        /// Gets the conversion of binary data to/from string feature.
+        /// </summary>
+        public static Feature ConvertOperatorBinDataToFromString => __convertOperatorBinDataToFromString;
+
         /// <summary>
         /// Gets the create index commit quorum feature.
         /// </summary>

src/MongoDB.Driver/Linq/Linq3Implementation/Ast/AstEnumExtensions.cs

@@ -0,0 +1,61 @@
+/* Copyright 2010-present MongoDB Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+using System;
+using MongoDB.Bson;
+
+namespace MongoDB.Driver.Linq.Linq3Implementation.Ast
+{
+    internal static class AstEnumExtensions
+    {
+        public static string Render(this BsonType type)
+        {
+            return type switch
+            {
+                BsonType.Array => "array",
+                BsonType.Binary => "binData",
+                BsonType.Boolean => "bool",
+                BsonType.DateTime => "date",
+                BsonType.Decimal128 => "decimal",
+                BsonType.Document => "object",
+                BsonType.Double => "double",
+                BsonType.Int32 => "int",
+                BsonType.Int64 => "long",
+                BsonType.JavaScript => "javascript",
+                BsonType.JavaScriptWithScope => "javascriptWithScope",
+                BsonType.MaxKey => "maxKey",
+                BsonType.MinKey => "minKey",
+                BsonType.Null => "null",
+                BsonType.ObjectId => "objectId",
+                BsonType.RegularExpression => "regex",
+                BsonType.String => "string",
+                BsonType.Symbol => "symbol",
+                BsonType.Timestamp => "timestamp",
+                BsonType.Undefined => "undefined",
+                _ => throw new ArgumentException($"Unexpected BSON type: {type}.", nameof(type))
+            };
+        }
+
+        public static string Render(this ByteOrder byteOrder)
+        {
+            return byteOrder switch
+            {
+                ByteOrder.BigEndian => "big",
+                ByteOrder.LittleEndian => "little",
+                _ => throw new ArgumentException($"Unexpected {nameof(ByteOrder)}: {byteOrder}.", nameof(byteOrder))
+            };
+        }
+    }
+}

src/MongoDB.Driver/Linq/Linq3Implementation/Ast/Expressions/AstConvertExpression.cs

@@ -21,27 +21,39 @@ namespace MongoDB.Driver.Linq.Linq3Implementation.Ast.Expressions
 {
     internal sealed class AstConvertExpression : AstExpression
     {
+        private readonly ByteOrder? _byteOrder;
+        private readonly string _format;
         private readonly AstExpression _input;
         private readonly AstExpression _onError;
         private readonly AstExpression _onNull;
+        private readonly BsonBinarySubType? _subType;
         private readonly AstExpression _to;
 
         public AstConvertExpression(
             AstExpression input,
             AstExpression to,
+            BsonBinarySubType? subType = null,
+            ByteOrder? byteOrder = null,
+            string format = null,
             AstExpression onError = null,
             AstExpression onNull = null)
         {
             _input = Ensure.IsNotNull(input, nameof(input));
             _to = Ensure.IsNotNull(to, nameof(to));
+            _subType = subType;
+            _byteOrder = byteOrder;
+            _format = format;
             _onError = onError;
             _onNull = onNull;
         }
 
+        public ByteOrder? ByteOrder => _byteOrder;
+        public string Format => _format;
         public AstExpression Input => _input;
         public override AstNodeType NodeType => AstNodeType.ConvertExpression;
         public AstExpression OnError => _onError;
         public AstExpression OnNull => _onNull;
+        public BsonBinarySubType? SubType => _subType;
         public AstExpression To => _to;
 
         public override AstNode Accept(AstNodeVisitor visitor)
@@ -56,9 +68,18 @@ public override BsonValue Render()
                 { "$convert", new BsonDocument
                     {
                         { "input", _input.Render() },
-                        { "to", _to.Render() },
+                        { "to", _to.Render(), _subType == null },
+                        { "to", () => new BsonDocument
+                            {
+                                { "type", _to.Render() },
+                                { "subtype", (int)_subType!.Value},
+                            },
+                            _subType != null
+                        },
                         { "onError", () => _onError.Render(), _onError != null },
-                        { "onNull", () => _onNull.Render(), _onNull != null }
+                        { "onNull", () => _onNull.Render(), _onNull != null },
+                        { "format", () => _format, _format != null },
+                        { "byteOrder", () => _byteOrder!.Value.Render(), _byteOrder != null }
                     }
                 }
             };
@@ -75,7 +96,7 @@ public AstConvertExpression Update(
                 return this;
             }
 
-            return new AstConvertExpression(input, to, onError, onNull);
+            return new AstConvertExpression(input, to, _subType, _byteOrder, _format, onError, onNull);
         }
     }
 }

src/MongoDB.Driver/Linq/Linq3Implementation/Ast/Expressions/AstExpression.cs

@@ -255,16 +255,21 @@ public static AstExpression Constant(BsonValue value)
             return new AstConstantExpression(value);
         }
 
-        public static AstExpression Convert(AstExpression input, AstExpression to, AstExpression onError = null, AstExpression onNull = null)
+        public static AstExpression Convert(
+            AstExpression input,
+            AstExpression to,
+            BsonBinarySubType? subType = null,
+            ByteOrder? byteOrder = null,
+            string format = null,
+            AstExpression onError = null,
+            AstExpression onNull = null)
         {
             Ensure.IsNotNull(input, nameof(input));
             Ensure.IsNotNull(to, nameof(to));
 
-            if (to is AstConstantExpression toConstantExpression &&
-                (toConstantExpression.Value as BsonString)?.Value is string toValue &&
-                toValue != null &&
-                onError == null &&
-                onNull == null)
+            if (onError == null && onNull == null && subType == null && format == null && byteOrder == null &&
+                to is AstConstantExpression toConstantExpression &&
+                (toConstantExpression.Value as BsonString)?.Value is { } toValue)
             {
                 var unaryOperator = toValue switch
                 {
@@ -278,13 +283,14 @@ public static AstExpression Convert(AstExpression input, AstExpression to, AstEx
                     "string" => AstUnaryOperator.ToString,
                     _ => (AstUnaryOperator?)null
                 };
+
                 if (unaryOperator.HasValue)
                 {
                     return AstExpression.Unary(unaryOperator.Value, input);
                 }
             }
 
-            return new AstConvertExpression(input, to, onError, onNull);
+            return new AstConvertExpression(input, to, subType, byteOrder, format, onError, onNull);
         }
 
         public static AstExpression DateAdd(

src/MongoDB.Driver/Linq/Linq3Implementation/Reflection/MqlMethod.cs

@@ -23,6 +23,7 @@ namespace MongoDB.Driver.Linq.Linq3Implementation.Reflection
     internal static class MqlMethod
     {
         // private static fields
+        private static readonly MethodInfo __convert;
         private static readonly MethodInfo __constantWithRepresentation;
         private static readonly MethodInfo __constantWithSerializer;
         private static readonly MethodInfo __dateFromString;
@@ -37,6 +38,7 @@ internal static class MqlMethod
         // static constructor
         static MqlMethod()
         {
+            __convert = ReflectionInfo.Method((object value, ConvertOptions<object> options) => Mql.Convert(value, options));
             __constantWithRepresentation = ReflectionInfo.Method((object value, BsonType representation) => Mql.Constant(value, representation));
             __constantWithSerializer = ReflectionInfo.Method((object value, IBsonSerializer<object> serializer) => Mql.Constant(value, serializer));
             __dateFromString = ReflectionInfo.Method((string dateStringl) => Mql.DateFromString(dateStringl));
@@ -50,6 +52,7 @@ static MqlMethod()
         }
 
         // public properties
+        public static MethodInfo Convert => __convert;
         public static MethodInfo ConstantWithRepresentation => __constantWithRepresentation;
         public static MethodInfo ConstantWithSerializer => __constantWithSerializer;
         public static MethodInfo DateFromString => __dateFromString;

src/MongoDB.Driver/Linq/Linq3Implementation/Translators/ExpressionToAggregationExpressionTranslators/ConstantExpressionToAggregationExpressionTranslator.cs

@@ -14,7 +14,6 @@
 */
 
 using System.Linq.Expressions;
-using MongoDB.Bson.IO;
 using MongoDB.Bson.Serialization;
 using MongoDB.Driver.Linq.Linq3Implementation.Ast.Expressions;
 using MongoDB.Driver.Linq.Linq3Implementation.Serializers;

src/MongoDB.Driver/Linq/Linq3Implementation/Translators/ExpressionToAggregationExpressionTranslators/MemberExpressionToAggregationExpressionTranslator.cs

@@ -43,7 +43,6 @@ public static TranslatedExpression Translate(TranslationContext context, MemberE
                 {
                     case "HasValue": return HasValuePropertyToAggregationExpressionTranslator.Translate(context, expression);
                     case "Value": return ValuePropertyToAggregationExpressionTranslator.Translate(context, expression);
-                    default: break;
                 }
             }
 
@@ -66,7 +65,7 @@ public static TranslatedExpression Translate(TranslationContext context, MemberE
 
             if (!DocumentSerializerHelper.AreMembersRepresentedAsFields(containerTranslation.Serializer, out _))
             {
-                if (member is PropertyInfo propertyInfo  && propertyInfo.Name == "Length")
+                if (member is PropertyInfo propertyInfo && propertyInfo.Name == "Length")
                 {
                     return LengthPropertyToAggregationExpressionTranslator.Translate(context, expression);
                 }

src/MongoDB.Driver/Linq/Linq3Implementation/Translators/ExpressionToAggregationExpressionTranslators/MethodCallExpressionToAggregationExpressionTranslator.cs

@@ -39,6 +39,7 @@ public static TranslatedExpression Translate(TranslationContext context, MethodC
                 case "Contains": return ContainsMethodToAggregationExpressionTranslator.Translate(context, expression);
                 case "ContainsKey": return ContainsKeyMethodToAggregationExpressionTranslator.Translate(context, expression);
                 case "ContainsValue": return ContainsValueMethodToAggregationExpressionTranslator.Translate(context, expression);
+                case "Convert": return ConvertMethodToAggregationExpressionTranslator.Translate(context, expression);
                 case "CovariancePopulation": return CovariancePopulationMethodToAggregationExpressionTranslator.Translate(context, expression);
                 case "CovarianceSample": return CovarianceSampleMethodToAggregationExpressionTranslator.Translate(context, expression);
                 case "Create": return CreateMethodToAggregationExpressionTranslator.Translate(context, expression);