CSHARP-3207: Support parsing uuid as extended JSON representation for subtype 4 binary

Author: MikalaiMazurenka

src/MongoDB.Bson/IO/JsonReader.cs

@@ -1357,6 +1357,7 @@ private BsonType ParseExtendedJson()
                     case "$symbol": _currentValue = ParseSymbolExtendedJson(); return BsonType.Symbol;
                     case "$timestamp": _currentValue = ParseTimestampExtendedJson(); return BsonType.Timestamp;
                     case "$undefined": _currentValue = ParseUndefinedExtendedJson(); return BsonType.Undefined;
+                    case "$uuid": _currentValue = ParseUuidExtendedJson(); return BsonType.Binary;
                 }
             }
             ReturnToBookmark(bookmark);
@@ -2077,6 +2078,28 @@ private BsonValue ParseUndefinedExtendedJson()
             return BsonMaxKey.Value;
         }
 
+        private BsonValue ParseUuidExtendedJson()
+        {
+            VerifyToken(":");
+            var uuidToken = PopToken();
+            if (uuidToken.Type != JsonTokenType.String)
+            {
+                var message = string.Format("JSON reader expected a string but found '{0}'.", uuidToken.Lexeme);
+                throw new FormatException(message);
+            }
+            VerifyToken("}");
+
+            var hexString = uuidToken.StringValue.Replace("-", "");
+            var bytes = BsonUtils.ParseHexString(hexString);
+            if (bytes.Length != 16)
+            {
+                var message = string.Format("Invalid $uuid string: '{0}'.", hexString);
+                throw new FormatException(message);
+            }
+
+            return new BsonBinaryData(bytes, BsonBinarySubType.UuidStandard);
+        }
+
         private BsonValue ParseUUIDConstructor(string uuidConstructorName)
         {
             VerifyToken("(");

tests/MongoDB.Bson.Tests/Specifications/bson-corpus/tests/binary.json

@@ -39,6 +39,12 @@
             "canonical_bson": "1D000000057800100000000473FFD26444B34C6990E8E7D1DFC035D400",
             "canonical_extjson": "{\"x\" : { \"$binary\" : {\"base64\" : \"c//SZESzTGmQ6OfR38A11A==\", \"subType\" : \"04\"}}}"
         },
+        {
+            "description": "subtype 0x04 UUID",
+            "canonical_bson": "1D000000057800100000000473FFD26444B34C6990E8E7D1DFC035D400",
+            "canonical_extjson": "{\"x\" : { \"$binary\" : {\"base64\" : \"c//SZESzTGmQ6OfR38A11A==\", \"subType\" : \"04\"}}}",
+            "degenerate_extjson": "{\"x\" : { \"$uuid\" : \"73ffd264-44b3-4c69-90e8-e7d1dfc035d4\"}}"
+        },
         {
             "description": "subtype 0x05",
             "canonical_bson": "1D000000057800100000000573FFD26444B34C6990E8E7D1DFC035D400",
@@ -81,5 +87,15 @@
             "description": "subtype 0x02 length negative one",
             "bson": "130000000578000600000002FFFFFFFFFFFF00"
         }
+    ],
+    "parseErrors": [
+        {
+            "description": "$uuid wrong type",
+            "string": "{\"x\" : { \"$uuid\" : { \"data\" : \"73ffd264-44b3-4c69-90e8-e7d1dfc035d4\"}}}"
+        },
+        {
+            "description": "$uuid invalid value",
+            "string": "{\"x\" : { \"$uuid\" : \"73ffd264-44b3-90e8-e7d1dfc035d4\"}}"
+        }
     ]
 }