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csv.rs
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use crate::common::lock::PyMutex;
use crate::vm::{
builtins::{PyStr, PyStrRef},
function::{ArgIterable, ArgumentError, FromArgs, FuncArgs},
match_class, named_function,
protocol::{PyIter, PyIterReturn},
py_module,
slots::{IteratorIterable, SlotIterator},
types::create_simple_type,
PyClassImpl, PyObjectRef, PyRef, PyResult, PyValue, TryFromObject, TypeProtocol,
VirtualMachine,
};
use itertools::{self, Itertools};
use std::fmt;
#[repr(i32)]
pub enum QuoteStyle {
Minimal = 0,
All = 1,
Nonnumeric = 2,
None = 3,
}
struct FormatOptions {
delimiter: u8,
quotechar: u8,
}
impl FromArgs for FormatOptions {
fn from_args(vm: &VirtualMachine, args: &mut FuncArgs) -> Result<Self, ArgumentError> {
let delimiter = if let Some(delimiter) = args.kwargs.remove("delimiter") {
PyStrRef::try_from_object(vm, delimiter)?
.as_str()
.bytes()
.exactly_one()
.map_err(|_| {
let msg = r#""delimiter" must be a 1-character string"#;
vm.new_type_error(msg.to_owned())
})?
} else {
b','
};
let quotechar = if let Some(quotechar) = args.kwargs.remove("quotechar") {
PyStrRef::try_from_object(vm, quotechar)?
.as_str()
.bytes()
.exactly_one()
.map_err(|_| {
let msg = r#""quotechar" must be a 1-character string"#;
vm.new_type_error(msg.to_owned())
})?
} else {
b'"'
};
Ok(FormatOptions {
delimiter,
quotechar,
})
}
}
impl FormatOptions {
fn to_reader(&self) -> csv_core::Reader {
csv_core::ReaderBuilder::new()
.delimiter(self.delimiter)
.quote(self.quotechar)
.terminator(csv_core::Terminator::CRLF)
.build()
}
fn to_writer(&self) -> csv_core::Writer {
csv_core::WriterBuilder::new()
.delimiter(self.delimiter)
.quote(self.quotechar)
.terminator(csv_core::Terminator::CRLF)
.build()
}
}
struct ReadState {
buffer: Vec<u8>,
output_ends: Vec<usize>,
reader: csv_core::Reader,
}
#[pyclass(module = "_csv", name = "reader")]
#[derive(PyValue)]
struct Reader {
iter: PyIter,
state: PyMutex<ReadState>,
}
impl fmt::Debug for Reader {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "_csv.reader")
}
}
#[pyimpl(with(SlotIterator))]
impl Reader {}
impl IteratorIterable for Reader {}
impl SlotIterator for Reader {
fn next(zelf: &PyRef<Self>, vm: &VirtualMachine) -> PyResult<PyIterReturn> {
let string = match zelf.iter.next(vm)? {
PyIterReturn::Return(obj) => obj,
PyIterReturn::StopIteration(v) => return Ok(PyIterReturn::StopIteration(v)),
};
let string = string.downcast::<PyStr>().map_err(|obj| {
vm.new_type_error(format!(
"iterator should return strings, not {} (the file should be opened in text mode)",
obj.class().name()
))
})?;
let input = string.as_str().as_bytes();
let mut state = zelf.state.lock();
let ReadState {
buffer,
output_ends,
reader,
} = &mut *state;
let mut input_offset = 0;
let mut output_offset = 0;
let mut output_ends_offset = 0;
loop {
let (res, nread, nwritten, nends) = reader.read_record(
&input[input_offset..],
&mut buffer[output_offset..],
&mut output_ends[output_ends_offset..],
);
input_offset += nread;
output_offset += nwritten;
output_ends_offset += nends;
match res {
csv_core::ReadRecordResult::InputEmpty => {}
csv_core::ReadRecordResult::OutputFull => resize_buf(buffer),
csv_core::ReadRecordResult::OutputEndsFull => resize_buf(output_ends),
csv_core::ReadRecordResult::Record => break,
csv_core::ReadRecordResult::End => return Ok(PyIterReturn::StopIteration(None)),
}
}
let rest = &input[input_offset..];
if !rest.iter().all(|&c| matches!(c, b'\r' | b'\n')) {
return Err(vm.new_value_error(
"new-line character seen in unquoted field - \
do you need to open the file in universal-newline mode?"
.to_owned(),
));
}
let mut prev_end = 0;
let out = output_ends[..output_ends_offset]
.iter()
.map(|&end| {
let range = prev_end..end;
prev_end = end;
std::str::from_utf8(&buffer[range])
.map(|s| vm.ctx.new_utf8_str(s.to_owned()))
// not sure if this is possible - the input was all strings
.map_err(|_e| vm.new_unicode_decode_error("csv not utf8".to_owned()))
})
.collect::<Result<_, _>>()?;
Ok(PyIterReturn::Return(vm.ctx.new_list(out)))
}
}
fn _csv_reader(
iter: PyIter,
options: FormatOptions,
// TODO: handle quote style, etc
_rest: FuncArgs,
_vm: &VirtualMachine,
) -> PyResult<Reader> {
Ok(Reader {
iter,
state: PyMutex::new(ReadState {
buffer: vec![0; 1024],
output_ends: vec![0; 16],
reader: options.to_reader(),
}),
})
}
struct WriteState {
buffer: Vec<u8>,
writer: csv_core::Writer,
}
#[pyclass(module = "_csv", name = "writer")]
#[derive(PyValue)]
struct Writer {
write: PyObjectRef,
state: PyMutex<WriteState>,
}
impl fmt::Debug for Writer {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "_csv.writer")
}
}
#[pyimpl]
impl Writer {
#[pymethod]
fn writerow(&self, row: PyObjectRef, vm: &VirtualMachine) -> PyResult {
let mut state = self.state.lock();
let WriteState { buffer, writer } = &mut *state;
let mut buffer_offset = 0;
macro_rules! handle_res {
($x:expr) => {{
let (res, nwritten) = $x;
buffer_offset += nwritten;
match res {
csv_core::WriteResult::InputEmpty => break,
csv_core::WriteResult::OutputFull => resize_buf(buffer),
}
}};
}
let row = ArgIterable::try_from_object(vm, row)?;
for field in row.iter(vm)? {
let field: PyObjectRef = field?;
let stringified;
let data: &[u8] = match_class!(match field {
ref s @ PyStr => s.as_str().as_bytes(),
crate::builtins::PyNone => b"",
ref obj => {
stringified = vm.to_str(obj)?;
stringified.as_str().as_bytes()
}
});
let mut input_offset = 0;
loop {
let (res, nread, nwritten) =
writer.field(&data[input_offset..], &mut buffer[buffer_offset..]);
input_offset += nread;
handle_res!((res, nwritten));
}
loop {
handle_res!(writer.delimiter(&mut buffer[buffer_offset..]));
}
}
loop {
handle_res!(writer.terminator(&mut buffer[buffer_offset..]));
}
let s = std::str::from_utf8(&buffer[..buffer_offset])
.map_err(|_| vm.new_unicode_decode_error("csv not utf8".to_owned()))?;
vm.invoke(&self.write, (s.to_owned(),))
}
#[pymethod]
fn writerows(&self, rows: ArgIterable, vm: &VirtualMachine) -> PyResult<()> {
for row in rows.iter(vm)? {
self.writerow(row?, vm)?;
}
Ok(())
}
}
fn _csv_writer(
file: PyObjectRef,
options: FormatOptions,
// TODO: handle quote style, etc
_rest: FuncArgs,
vm: &VirtualMachine,
) -> PyResult<Writer> {
let write = match vm.get_attribute_opt(file.clone(), "write")? {
Some(write_meth) => write_meth,
None if vm.is_callable(&file) => file,
None => return Err(vm.new_type_error("argument 1 must have a \"write\" method".to_owned())),
};
Ok(Writer {
write,
state: PyMutex::new(WriteState {
buffer: vec![0; 1024],
writer: options.to_writer(),
}),
})
}
#[inline]
fn resize_buf<T: num_traits::PrimInt>(buf: &mut Vec<T>) {
let new_size = buf.len() * 2;
buf.resize(new_size, T::zero());
}
pub fn make_module(vm: &VirtualMachine) -> PyObjectRef {
let ctx = &vm.ctx;
Reader::make_class(ctx);
Writer::make_class(ctx);
let error = create_simple_type("Error", &ctx.exceptions.exception_type);
py_module!(vm, "_csv", {
"reader" => named_function!(ctx, _csv, reader),
"writer" => named_function!(ctx, _csv, writer),
"Error" => error,
// constants
"QUOTE_MINIMAL" => ctx.new_int(QuoteStyle::Minimal as i32),
"QUOTE_ALL" => ctx.new_int(QuoteStyle::All as i32),
"QUOTE_NONNUMERIC" => ctx.new_int(QuoteStyle::Nonnumeric as i32),
"QUOTE_NONE" => ctx.new_int(QuoteStyle::None as i32),
})
}