Function test_default_encoder_byte_array

arrow-json/src/writer/mod.rs:2488–2565

()

    #[test]
    fn test_default_encoder_byte_array() {
        struct IntArrayBinaryEncoder<B> {
            array: B,
        }

        impl<'a, B> Encoder for IntArrayBinaryEncoder<B>
        where
            B: ArrayAccessor<Item = &'a [u8]>,
        {
            fn encode(&mut self, idx: usize, out: &mut Vec<u8>) {
                out.push(b'[');
                let child = self.array.value(idx);
                for (idx, byte) in child.iter().enumerate() {
                    write!(out, "{byte}").unwrap();
                    if idx < child.len() - 1 {
                        out.push(b',');
                    }
                }
                out.push(b']');
            }
        }

        #[derive(Debug)]
        struct IntArayBinaryEncoderFactory;

        impl EncoderFactory for IntArayBinaryEncoderFactory {
            fn make_default_encoder<'a>(
                &self,
                _field: &'a FieldRef,
                array: &'a dyn Array,
                _options: &'a EncoderOptions,
            ) -> Result<Option<NullableEncoder<'a>>, ArrowError> {
                match array.data_type() {
                    DataType::Binary => {
                        let array = array.as_binary::<i32>();
                        let encoder = IntArrayBinaryEncoder { array };
                        let array_encoder = Box::new(encoder) as Box<dyn Encoder + 'a>;
                        let nulls = array.nulls().cloned();
                        Ok(Some(NullableEncoder::new(array_encoder, nulls)))
                    }
                    _ => Ok(None),
                }
            }
        }

        let binary_array = BinaryArray::from_opt_vec(vec![Some(b"a"), None, Some(b"b")]);
        let float_array = Float64Array::from(vec![Some(1.0), Some(2.3), None]);
        let fields = vec![
            Field::new("bytes", DataType::Binary, true),
            Field::new("float", DataType::Float64, true),
        ];
        let batch = RecordBatch::try_new(
            Arc::new(Schema::new(fields)),
            vec![
                Arc::new(binary_array) as Arc<dyn Array>,
                Arc::new(float_array) as Arc<dyn Array>,
            ],
        )