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()
}