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use dataflow_types::{sources::encoding::CsvEncoding, DecodeError, LinearOperator};
use repr::{Datum, Row};
#[derive(Debug)]
pub struct CsvDecoderState {
next_row_is_header: bool,
header_names: Option<Vec<String>>,
n_cols: usize,
output: Vec<u8>,
output_cursor: usize,
ends: Vec<usize>,
ends_cursor: usize,
csv_reader: csv_core::Reader,
demanded: Vec<bool>,
row_packer: Row,
events_error: usize,
events_success: usize,
}
impl CsvDecoderState {
fn total_events(&self) -> usize {
self.events_error + self.events_success
}
pub fn new(format: CsvEncoding, operators: &mut Option<LinearOperator>) -> Self {
let CsvEncoding { columns, delimiter } = format;
let n_cols = columns.arity();
let operators = operators.take();
let demanded = (0..n_cols)
.map(move |c| {
operators
.as_ref()
.map(|o| o.projection.contains(&c))
.unwrap_or(true)
})
.collect::<Vec<_>>();
let header_names = columns.into_header_names();
Self {
next_row_is_header: header_names.is_some(),
header_names,
n_cols,
output: vec![0],
output_cursor: 0,
ends: vec![0],
ends_cursor: 1,
csv_reader: csv_core::ReaderBuilder::new().delimiter(delimiter).build(),
demanded,
row_packer: Default::default(),
events_error: 0,
events_success: 0,
}
}
pub fn reset_for_new_object(&mut self) {
if self.header_names.is_some() {
self.next_row_is_header = true;
}
}
pub fn decode(&mut self, chunk: &mut &[u8]) -> Result<Option<Row>, DecodeError> {
loop {
let (result, n_input, n_output, n_ends) = self.csv_reader.read_record(
*chunk,
&mut self.output[self.output_cursor..],
&mut self.ends[self.ends_cursor..],
);
self.output_cursor += n_output;
*chunk = &(*chunk)[n_input..];
self.ends_cursor += n_ends;
match result {
csv_core::ReadRecordResult::InputEmpty => break Ok(None),
csv_core::ReadRecordResult::OutputFull => {
let length = self.output.len();
self.output.extend(std::iter::repeat(0).take(length));
}
csv_core::ReadRecordResult::OutputEndsFull => {
let length = self.ends.len();
self.ends.extend(std::iter::repeat(0).take(length));
}
csv_core::ReadRecordResult::Record | csv_core::ReadRecordResult::End => {
let result = {
let ends_valid = self.ends_cursor - 1;
if ends_valid == 0 {
break Ok(None);
}
if ends_valid != self.n_cols {
self.events_error += 1;
Err(DecodeError::Text(format!(
"CSV error at record number {}: expected {} columns, got {}.",
self.total_events(),
self.n_cols,
ends_valid
)))
} else {
match std::str::from_utf8(&self.output[0..self.output_cursor]) {
Ok(output) => {
self.events_success += 1;
let mut row_packer = std::mem::take(&mut self.row_packer);
row_packer.extend((0..self.n_cols).map(|i| {
Datum::String(
if self.next_row_is_header || self.demanded[i] {
&output[self.ends[i]..self.ends[i + 1]]
} else {
""
},
)
}));
self.row_packer = row_packer;
self.output_cursor = 0;
self.ends_cursor = 1;
Ok(Some(self.row_packer.finish_and_reuse()))
}
Err(e) => {
self.events_error += 1;
Err(DecodeError::Text(format!(
"CSV error at record number {}: invalid UTF-8 ({})",
self.total_events(),
e
)))
}
}
}
};
if self.next_row_is_header {
self.next_row_is_header = false;
if let Ok(Some(row)) = &result {
let mismatched = row
.iter()
.zip(self.header_names.iter().flatten())
.enumerate()
.find(|(_, (actual, expected))| actual.unwrap_str() != &**expected);
if let Some((i, (actual, expected))) = mismatched {
break Err(DecodeError::Text(format!(
"source file contains incorrect columns '{:?}', \
first mismatched column at index {} expected={} actual={}",
row,
i + 1,
expected,
actual
)));
}
}
if chunk.is_empty() {
break Ok(None);
} else if result.is_err() {
break result;
}
} else {
break result;
}
}
}
}
}
}