[GitHub] [arrow] ovr commented on a change in pull request #9139: ARROW-11188: [Rust] Support crypto functions from PostgreSQL dialect …

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ovr commented on a change in pull request #9139:
URL: https://github.com/apache/arrow/pull/9139#discussion_r554424637



##########
File path: rust/datafusion/src/physical_plan/crypto_expressions.rs
##########
@@ -0,0 +1,114 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you 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.
+
+//! Crypto expressions
+
+use md5::Md5;
+use sha2::{
+    digest::Output as SHA2DigestOutput, Digest as SHA2Digest, Sha224, Sha256, Sha384,
+    Sha512,
+};
+
+use crate::error::{DataFusionError, Result};
+use arrow::array::{
+    ArrayRef, BinaryBuilder, GenericBinaryArray, GenericStringArray,
+    StringOffsetSizeTrait,
+};
+
+fn md5_process(input: &str) -> String {
+    let mut digest = Md5::default();
+    digest.update(&input);
+
+    let mut result = String::new();
+
+    for byte in &digest.finalize() {
+        result.push_str(&format!("{:02x}", byte));
+    }
+
+    result
+}
+
+// It's not possible to return &[u8], because trait in trait without short lifetime
+fn sha_process<D: SHA2Digest + Default>(input: &str) -> SHA2DigestOutput<D> {
+    let mut digest = D::default();
+    digest.update(&input);
+
+    digest.finalize()
+}
+
+macro_rules! crypto_unary_string_function {
+    ($NAME:ident, $FUNC:expr) => {
+        /// crypto function that accepts Utf8 or LargeUtf8 and returns Utf8 string
+        pub fn $NAME<T: StringOffsetSizeTrait>(
+            args: &[ArrayRef],
+        ) -> Result<GenericStringArray<i32>> {
+            if args.len() != 1 {
+                return Err(DataFusionError::Internal(format!(
+                    "{:?} args were supplied but {} takes exactly one argument",
+                    args.len(),
+                    String::from(stringify!($NAME)),
+                )));
+            }
+
+            let array = args[0]
+                .as_any()
+                .downcast_ref::<GenericStringArray<T>>()
+                .unwrap();
+
+            // first map is the iterator, second is for the `Option<_>`
+            Ok(array.iter().map(|x| x.map(|x| $FUNC(x))).collect())
+        }
+    };
+}
+
+macro_rules! crypto_unary_binary_function {
+    ($NAME:ident, $FUNC:expr) => {
+        /// crypto function that accepts Utf8 or LargeUtf8 and returns Binary
+        pub fn $NAME<T: StringOffsetSizeTrait>(
+            args: &[ArrayRef],
+        ) -> Result<GenericBinaryArray<i32>> {
+            if args.len() != 1 {
+                return Err(DataFusionError::Internal(format!(
+                    "{:?} args were supplied but {} takes exactly one argument",
+                    args.len(),
+                    String::from(stringify!($NAME)),
+                )));
+            }
+
+            let array = args[0]
+                .as_any()
+                .downcast_ref::<GenericStringArray<T>>()
+                .unwrap();
+
+            let mut builder = BinaryBuilder::new(args.len());
+
+            for value in array.iter() {
+                builder
+                    .append_value($FUNC(value.unwrap()).as_slice())
+                    .unwrap();
+            }

Review comment:
       Yes, it will crash.
   
   Replaced this with `Ok(array.iter().map(|x| x.map(|x| $FUNC(x))).collect())` without as_slice
   And it works. Weird, Where `SHA2DigestOutput<D>` converted to slice.
   
   




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