Implement serialization for ScalarValue::FixedSizeBinary (apache#3943)

* Implement serialization for ScalarValue::FixedSizeBinary

* correct test

* fix formatting

* add none test case for non zero length

Co-authored-by: Andrew Lamb <andrew@nerdnetworks.org>

* resolve conflict

Co-authored-by: Andrew Lamb <andrew@nerdnetworks.org>

Author: retikulum

datafusion/proto/proto/datafusion.proto

@@ -770,6 +770,11 @@ message StructValue {
   repeated Field fields = 3;
 }
 
+message ScalarFixedSizeBinary{
+    bytes values =  1;
+    int32 length = 2;
+}
+
 message ScalarValue{
   // was PrimitiveScalarType null_value = 19;
   reserved 19;
@@ -808,6 +813,7 @@ message ScalarValue{
         int64 time64_value = 30;
         IntervalMonthDayNanoValue interval_month_day_nano = 31;
         StructValue struct_value = 32;
+        ScalarFixedSizeBinary fixed_size_binary_value = 34;
     }
 }
 

datafusion/proto/src/from_proto.rs

@@ -651,6 +651,9 @@ impl TryFrom<&protobuf::ScalarValue> for ScalarValue {
 
                 Self::Struct(values, Box::new(fields))
             }
+            Value::FixedSizeBinaryValue(v) => {
+                Self::FixedSizeBinary(v.length, Some(v.clone().values))
+            }
         })
     }
 }

datafusion/proto/src/lib.rs

@@ -682,6 +682,12 @@ mod roundtrip_tests {
                     Field::new("a", DataType::Boolean, false),
                 ]),
             ),
+            ScalarValue::FixedSizeBinary(
+                b"bar".to_vec().len() as i32,
+                Some(b"bar".to_vec()),
+            ),
+            ScalarValue::FixedSizeBinary(0, None),
+            ScalarValue::FixedSizeBinary(5, None),
         ];
 
         for test_case in should_pass.into_iter() {

datafusion/proto/src/to_proto.rs

@@ -1033,9 +1033,14 @@ impl TryFrom<&ScalarValue> for protobuf::ScalarValue {
                     Value::LargeBinaryValue(s.to_owned())
                 })
             }
-            scalar::ScalarValue::FixedSizeBinary(_, _) => Err(Error::General(
-                "FixedSizeBinary is not yet implemented".to_owned(),
-            )),
+            scalar::ScalarValue::FixedSizeBinary(length, val) => {
+                create_proto_scalar(val, &data_type, |s| {
+                    Value::FixedSizeBinaryValue(protobuf::ScalarFixedSizeBinary {
+                        values: s.to_owned(),
+                        length: *length,
+                    })
+                })
+            }
 
             datafusion::scalar::ScalarValue::Time64(v) => {
                 create_proto_scalar(v, &data_type, |v| Value::Time64Value(*v))