parquet_derive/lib.rs
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251
// 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.
//! This crate provides a procedural macro to derive
//! implementations of a RecordWriter and RecordReader
#![warn(missing_docs)]
#![recursion_limit = "128"]
extern crate proc_macro;
extern crate proc_macro2;
extern crate syn;
#[macro_use]
extern crate quote;
extern crate parquet;
use ::syn::{parse_macro_input, Data, DataStruct, DeriveInput};
mod parquet_field;
/// Derive flat, simple RecordWriter implementations.
///
/// Works by parsing a struct tagged with `#[derive(ParquetRecordWriter)]` and emitting
/// the correct writing code for each field of the struct. Column writers
/// are generated in the order they are defined.
///
/// It is up to the programmer to keep the order of the struct
/// fields lined up with the schema.
///
/// Example:
///
/// ```no_run
/// use parquet_derive::ParquetRecordWriter;
/// use std::io::{self, Write};
/// use parquet::file::properties::WriterProperties;
/// use parquet::file::writer::SerializedFileWriter;
/// use parquet::record::RecordWriter;
/// use std::fs::File;
///
/// use std::sync::Arc;
///
/// #[derive(ParquetRecordWriter)]
/// struct ACompleteRecord<'a> {
/// pub a_bool: bool,
/// pub a_str: &'a str,
/// }
///
/// pub fn write_some_records() {
/// let samples = vec![
/// ACompleteRecord {
/// a_bool: true,
/// a_str: "I'm true"
/// },
/// ACompleteRecord {
/// a_bool: false,
/// a_str: "I'm false"
/// }
/// ];
/// let file = File::open("some_file.parquet").unwrap();
///
/// let schema = samples.as_slice().schema().unwrap();
///
/// let mut writer = SerializedFileWriter::new(file, schema, Default::default()).unwrap();
///
/// let mut row_group = writer.next_row_group().unwrap();
/// samples.as_slice().write_to_row_group(&mut row_group).unwrap();
/// row_group.close().unwrap();
/// writer.close().unwrap();
/// }
/// ```
///
#[proc_macro_derive(ParquetRecordWriter)]
pub fn parquet_record_writer(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
let input: DeriveInput = parse_macro_input!(input as DeriveInput);
let fields = match input.data {
Data::Struct(DataStruct { fields, .. }) => fields,
Data::Enum(_) => unimplemented!("Enum currently is not supported"),
Data::Union(_) => unimplemented!("Union currently is not supported"),
};
let field_infos: Vec<_> = fields.iter().map(parquet_field::Field::from).collect();
let writer_snippets: Vec<proc_macro2::TokenStream> =
field_infos.iter().map(|x| x.writer_snippet()).collect();
let derived_for = input.ident;
let generics = input.generics;
let field_types: Vec<proc_macro2::TokenStream> =
field_infos.iter().map(|x| x.parquet_type()).collect();
(quote! {
impl #generics ::parquet::record::RecordWriter<#derived_for #generics> for &[#derived_for #generics] {
fn write_to_row_group<W: ::std::io::Write + Send>(
&self,
row_group_writer: &mut ::parquet::file::writer::SerializedRowGroupWriter<'_, W>
) -> Result<(), ::parquet::errors::ParquetError> {
use ::parquet::column::writer::ColumnWriter;
let mut row_group_writer = row_group_writer;
let records = &self; // Used by all the writer snippets to be more clear
#(
{
let mut some_column_writer = row_group_writer.next_column().unwrap();
if let Some(mut column_writer) = some_column_writer {
#writer_snippets
column_writer.close()?;
} else {
return Err(::parquet::errors::ParquetError::General("Failed to get next column".into()))
}
}
);*
Ok(())
}
fn schema(&self) -> Result<::parquet::schema::types::TypePtr, ::parquet::errors::ParquetError> {
use ::parquet::schema::types::Type as ParquetType;
use ::parquet::schema::types::TypePtr;
use ::parquet::basic::LogicalType;
let mut fields: ::std::vec::Vec<TypePtr> = ::std::vec::Vec::new();
#(
#field_types
);*;
let group = ParquetType::group_type_builder("rust_schema")
.with_fields(fields)
.build()?;
Ok(group.into())
}
}
}).into()
}
/// Derive flat, simple RecordReader implementations.
///
/// Works by parsing a struct tagged with `#[derive(ParquetRecordReader)]` and emitting
/// the correct writing code for each field of the struct. Column readers
/// are generated by matching names in the schema to the names in the struct.
///
/// It is up to the programmer to ensure the names in the struct
/// fields line up with the schema.
///
/// Example:
///
/// ```no_run
/// use parquet::record::RecordReader;
/// use parquet::file::{serialized_reader::SerializedFileReader, reader::FileReader};
/// use parquet_derive::{ParquetRecordReader};
/// use std::fs::File;
///
/// #[derive(ParquetRecordReader)]
/// struct ACompleteRecord {
/// pub a_bool: bool,
/// pub a_string: String,
/// }
///
/// pub fn read_some_records() -> Vec<ACompleteRecord> {
/// let mut samples: Vec<ACompleteRecord> = Vec::new();
/// let file = File::open("some_file.parquet").unwrap();
///
/// let reader = SerializedFileReader::new(file).unwrap();
/// let mut row_group = reader.get_row_group(0).unwrap();
/// samples.read_from_row_group(&mut *row_group, 1).unwrap();
/// samples
/// }
/// ```
///
#[proc_macro_derive(ParquetRecordReader)]
pub fn parquet_record_reader(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
let input: DeriveInput = parse_macro_input!(input as DeriveInput);
let fields = match input.data {
Data::Struct(DataStruct { fields, .. }) => fields,
Data::Enum(_) => unimplemented!("Enum currently is not supported"),
Data::Union(_) => unimplemented!("Union currently is not supported"),
};
let field_infos: Vec<_> = fields.iter().map(parquet_field::Field::from).collect();
let field_names: Vec<_> = fields.iter().map(|f| f.ident.clone()).collect();
let reader_snippets: Vec<proc_macro2::TokenStream> =
field_infos.iter().map(|x| x.reader_snippet()).collect();
let derived_for = input.ident;
let generics = input.generics;
(quote! {
impl #generics ::parquet::record::RecordReader<#derived_for #generics> for Vec<#derived_for #generics> {
fn read_from_row_group(
&mut self,
row_group_reader: &mut dyn ::parquet::file::reader::RowGroupReader,
num_records: usize,
) -> Result<(), ::parquet::errors::ParquetError> {
use ::parquet::column::reader::ColumnReader;
let mut row_group_reader = row_group_reader;
// key: parquet file column name, value: column index
let mut name_to_index = std::collections::HashMap::new();
for (idx, col) in row_group_reader.metadata().schema_descr().columns().iter().enumerate() {
name_to_index.insert(col.name().to_string(), idx);
}
for _ in 0..num_records {
self.push(#derived_for {
#(
#field_names: Default::default()
),*
})
}
let records = self; // Used by all the reader snippets to be more clear
#(
{
let idx: usize = match name_to_index.get(stringify!(#field_names)) {
Some(&col_idx) => col_idx,
None => {
let error_msg = format!("column name '{}' is not found in parquet file!", stringify!(#field_names));
return Err(::parquet::errors::ParquetError::General(error_msg));
}
};
if let Ok(mut column_reader) = row_group_reader.get_column_reader(idx) {
#reader_snippets
} else {
return Err(::parquet::errors::ParquetError::General("Failed to get next column".into()))
}
}
);*
Ok(())
}
}
}).into()
}