tustvold commented on code in PR #6820: URL: https://github.com/apache/arrow-rs/pull/6820#discussion_r1864883393
########## arrow-avro/src/reader/cursor.rs: ########## @@ -0,0 +1,140 @@ +// 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. + +use arrow_schema::ArrowError; + +/// A wrapper around a byte slice, providing low-level decoding for Avro +/// +/// <https://avro.apache.org/docs/1.11.1/specification/#encodings> +#[derive(Debug)] +pub(crate) struct AvroCursor<'a> { + buf: &'a [u8], + start_len: usize, +} + +impl<'a> AvroCursor<'a> { + pub(crate) fn new(buf: &'a [u8]) -> Self { + Self { + buf, + start_len: buf.len(), + } + } + + /// Returns the current cursor position + #[inline] + pub(crate) fn position(&self) -> usize { + self.start_len - self.buf.len() Review Comment: This is where start_len is used ########## arrow-avro/src/reader/cursor.rs: ########## @@ -0,0 +1,140 @@ +// 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. + +use arrow_schema::ArrowError; + +/// A wrapper around a byte slice, providing low-level decoding for Avro +/// +/// <https://avro.apache.org/docs/1.11.1/specification/#encodings> +#[derive(Debug)] +pub(crate) struct AvroCursor<'a> { + buf: &'a [u8], + start_len: usize, +} + +impl<'a> AvroCursor<'a> { + pub(crate) fn new(buf: &'a [u8]) -> Self { + Self { + buf, + start_len: buf.len(), + } + } + + /// Returns the current cursor position + #[inline] + pub(crate) fn position(&self) -> usize { + self.start_len - self.buf.len() + } + + /// Read a single `u8` + #[inline] + pub(crate) fn get_u8(&mut self) -> Result<u8, ArrowError> { + match self.buf.first().copied() { + Some(x) => { + self.buf = &self.buf[1..]; Review Comment: It gets used to compute the cursor "position" ########## arrow-avro/src/reader/record.rs: ########## @@ -0,0 +1,292 @@ +// 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. + +use crate::codec::{AvroDataType, Codec, Nullability}; +use crate::reader::block::{Block, BlockDecoder}; +use crate::reader::cursor::AvroCursor; +use crate::reader::header::Header; +use crate::schema::*; +use arrow_array::types::*; +use arrow_array::*; +use arrow_buffer::*; +use arrow_schema::{ + ArrowError, DataType, Field as ArrowField, FieldRef, Fields, Schema as ArrowSchema, SchemaRef, +}; +use std::collections::HashMap; +use std::io::Read; +use std::sync::Arc; + +/// Decodes avro encoded data into [`RecordBatch`] +pub struct RecordDecoder { + schema: SchemaRef, + fields: Vec<Decoder>, +} + +impl RecordDecoder { + pub fn try_new(data_type: &AvroDataType) -> Result<Self, ArrowError> { + match Decoder::try_new(data_type)? { + Decoder::Record(fields, encodings) => Ok(Self { + schema: Arc::new(ArrowSchema::new(fields)), + fields: encodings, + }), + encoding => Err(ArrowError::ParseError(format!( + "Expected record got {encoding:?}" + ))), + } + } + + pub fn schema(&self) -> &SchemaRef { + &self.schema + } + + /// Decode `count` records from `buf` + pub fn decode(&mut self, buf: &[u8], count: usize) -> Result<usize, ArrowError> { + let mut cursor = AvroCursor::new(buf); + for _ in 0..count { + for field in &mut self.fields { + field.decode(&mut cursor)?; + } + } + Ok(cursor.position()) + } + + /// Flush the decoded records into a [`RecordBatch`] + pub fn flush(&mut self) -> Result<RecordBatch, ArrowError> { + let arrays = self + .fields + .iter_mut() + .map(|x| x.flush(None)) + .collect::<Result<Vec<_>, _>>()?; + + RecordBatch::try_new(self.schema.clone(), arrays) + } +} + +#[derive(Debug)] +enum Decoder { + Null(usize), + Boolean(BooleanBufferBuilder), + Int32(Vec<i32>), + Int64(Vec<i64>), + Float32(Vec<f32>), + Float64(Vec<f64>), + Date32(Vec<i32>), + TimeMillis(Vec<i32>), + TimeMicros(Vec<i64>), + TimestampMillis(bool, Vec<i64>), + TimestampMicros(bool, Vec<i64>), + Binary(OffsetBufferBuilder<i32>, Vec<u8>), + String(OffsetBufferBuilder<i32>, Vec<u8>), + List(FieldRef, OffsetBufferBuilder<i32>, Box<Decoder>), + Record(Fields, Vec<Decoder>), + Nullable(Nullability, NullBufferBuilder, Box<Decoder>), +} + +impl Decoder { + fn try_new(data_type: &AvroDataType) -> Result<Self, ArrowError> { + let nyi = |s: &str| Err(ArrowError::NotYetImplemented(s.to_string())); + + let decoder = match data_type.codec() { + Codec::Null => Self::Null(0), + Codec::Boolean => Self::Boolean(BooleanBufferBuilder::new(DEFAULT_CAPACITY)), + Codec::Int32 => Self::Int32(Vec::with_capacity(DEFAULT_CAPACITY)), + Codec::Int64 => Self::Int64(Vec::with_capacity(DEFAULT_CAPACITY)), + Codec::Float32 => Self::Float32(Vec::with_capacity(DEFAULT_CAPACITY)), + Codec::Float64 => Self::Float64(Vec::with_capacity(DEFAULT_CAPACITY)), + Codec::Binary => Self::Binary( + OffsetBufferBuilder::new(DEFAULT_CAPACITY), + Vec::with_capacity(DEFAULT_CAPACITY), + ), + Codec::Utf8 => Self::String( + OffsetBufferBuilder::new(DEFAULT_CAPACITY), + Vec::with_capacity(DEFAULT_CAPACITY), + ), + Codec::Date32 => Self::Date32(Vec::with_capacity(DEFAULT_CAPACITY)), + Codec::TimeMillis => Self::TimeMillis(Vec::with_capacity(DEFAULT_CAPACITY)), + Codec::TimeMicros => Self::TimeMicros(Vec::with_capacity(DEFAULT_CAPACITY)), + Codec::TimestampMillis(is_utc) => { + Self::TimestampMillis(*is_utc, Vec::with_capacity(DEFAULT_CAPACITY)) + } + Codec::TimestampMicros(is_utc) => { + Self::TimestampMicros(*is_utc, Vec::with_capacity(DEFAULT_CAPACITY)) + } + Codec::Fixed(_) => return nyi("decoding fixed"), + Codec::Interval => return nyi("decoding interval"), + Codec::List(item) => { Review Comment: Yeah, I wanted to keep the diff smaller, definitely more testing is needed before we make any of this public (currently all the module is private) -- This is an automated message from the Apache Git Service. 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