Xuanwo commented on code in PR #6281: URL: https://github.com/apache/arrow-rs/pull/6281#discussion_r1724401483
########## parquet/src/util/vec_util.rs: ########## @@ -0,0 +1,63 @@ +// 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. + +/// Resize the `buf` to a new len `n` without initialization. +/// +/// Replacing `resize` on the `buf` with `reserve` and `set_len` can skip the initialization +/// cost for a good performance. +/// And the `set_len` here is safe because the element of the vector is byte whose destruction +/// does nothing. +// TODO: remove this clippy allow lint if it is used by a module without feature gate. Review Comment: How about hiding it within the same feature gate? ########## parquet/src/util/vec_util.rs: ########## @@ -0,0 +1,63 @@ +// 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. + +/// Resize the `buf` to a new len `n` without initialization. +/// +/// Replacing `resize` on the `buf` with `reserve` and `set_len` can skip the initialization +/// cost for a good performance. +/// And the `set_len` here is safe because the element of the vector is byte whose destruction +/// does nothing. +// TODO: remove this clippy allow lint if it is used by a module without feature gate. +#[allow(dead_code)] +pub fn resize_buffer_without_init(buf: &mut Vec<u8>, n: usize) { + if n > buf.capacity() { + buf.reserve(n - buf.len()); + } + unsafe { buf.set_len(n) }; Review Comment: How about adding a safety comment for `set_len` ########## parquet/src/compression.rs: ########## @@ -150,35 +150,47 @@ pub fn create_codec(codec: CodecType, _options: &CodecOptions) -> Result<Option< CodecType::BROTLI(level) => { #[cfg(any(feature = "brotli", test))] return Ok(Some(Box::new(BrotliCodec::new(level)))); - Err(ParquetError::General("Disabled feature at compile time: brotli".into())) - }, + Err(ParquetError::General( + "Disabled feature at compile time: brotli".into(), + )) + } CodecType::GZIP(level) => { #[cfg(any(feature = "flate2", test))] return Ok(Some(Box::new(GZipCodec::new(level)))); - Err(ParquetError::General("Disabled feature at compile time: flate2".into())) - }, + Err(ParquetError::General( + "Disabled feature at compile time: flate2".into(), + )) + } CodecType::SNAPPY => { #[cfg(any(feature = "snap", test))] return Ok(Some(Box::new(SnappyCodec::new()))); - Err(ParquetError::General("Disabled feature at compile time: snap".into())) - }, + Err(ParquetError::General( + "Disabled feature at compile time: snap".into(), + )) + } CodecType::LZ4 => { #[cfg(any(feature = "lz4", test))] return Ok(Some(Box::new(LZ4HadoopCodec::new( _options.backward_compatible_lz4, )))); - Err(ParquetError::General("Disabled feature at compile time: lz4".into())) - }, + Err(ParquetError::General( + "Disabled feature at compile time: lz4".into(), + )) + } CodecType::ZSTD(level) => { #[cfg(any(feature = "zstd", test))] return Ok(Some(Box::new(ZSTDCodec::new(level)))); - Err(ParquetError::General("Disabled feature at compile time: zstd".into())) - }, + Err(ParquetError::General( + "Disabled feature at compile time: zstd".into(), + )) + } CodecType::LZ4_RAW => { #[cfg(any(feature = "lz4", test))] return Ok(Some(Box::new(LZ4RawCodec::new()))); - Err(ParquetError::General("Disabled feature at compile time: lz4".into())) - }, + Err(ParquetError::General( + "Disabled feature at compile time: lz4".into(), Review Comment: Looks like unexpected format changes. -- This is an automated message from the Apache Git Service. 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