Prevent inspect the string data

Signed-off-by: Austin Liu <[email protected]>

arrow-string/src/length.rs

@@ -138,10 +138,15 @@ pub fn bit_length(array: &dyn Array) -> Result<ArrayRef, ArrowError> {
             let list = array.as_string::<i64>();
             Ok(bit_length_impl::<Int64Type>(list.offsets(), list.nulls()))
         }
-        DataType::Utf8View => Ok(Arc::new(Int32Array::from_unary(
-            array.as_string_view(),
-            |x| i32::mul_wrapping(x.bytes().len() as i32, 8),
-        ))),
+        DataType::Utf8View => {
+            let list = array.as_string_view();
+            let values = list
+                .views()
+                .iter()
+                .map(|view| (*view as i32).wrapping_mul(8))
+                .collect();
+            Ok(Arc::new(Int32Array::new(values, array.nulls().cloned())))
+        }
         DataType::Binary => {
             let list = array.as_binary::<i32>();
             Ok(bit_length_impl::<Int32Type>(list.offsets(), list.nulls()))