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use std::io::Write;
pub use fallible_streaming_iterator::FallibleStreamingIterator;
use crate::array::Array;
use crate::error::Error;
use super::super::json::write::new_serializer;
fn serialize(array: &dyn Array, buffer: &mut Vec<u8>) {
let mut serializer = new_serializer(array);
(0..array.len()).for_each(|_| {
buffer.extend_from_slice(serializer.next().unwrap());
buffer.push(b'\n');
});
}
#[derive(Debug, Clone)]
pub struct Serializer<A, I>
where
A: AsRef<dyn Array>,
I: Iterator<Item = Result<A, Error>>,
{
arrays: I,
buffer: Vec<u8>,
}
impl<A, I> Serializer<A, I>
where
A: AsRef<dyn Array>,
I: Iterator<Item = Result<A, Error>>,
{
pub fn new(arrays: I, buffer: Vec<u8>) -> Self {
Self { arrays, buffer }
}
}
impl<A, I> FallibleStreamingIterator for Serializer<A, I>
where
A: AsRef<dyn Array>,
I: Iterator<Item = Result<A, Error>>,
{
type Item = [u8];
type Error = Error;
fn advance(&mut self) -> Result<(), Error> {
self.buffer.clear();
self.arrays
.next()
.map(|maybe_array| maybe_array.map(|array| serialize(array.as_ref(), &mut self.buffer)))
.transpose()?;
Ok(())
}
fn get(&self) -> Option<&Self::Item> {
if !self.buffer.is_empty() {
Some(&self.buffer)
} else {
None
}
}
}
pub struct FileWriter<W, I>
where
W: Write,
I: FallibleStreamingIterator<Item = [u8], Error = Error>,
{
writer: W,
iterator: I,
}
impl<W, I> FileWriter<W, I>
where
W: Write,
I: FallibleStreamingIterator<Item = [u8], Error = Error>,
{
pub fn new(writer: W, iterator: I) -> Self {
Self { writer, iterator }
}
pub fn into_inner(self) -> (W, I) {
(self.writer, self.iterator)
}
}
impl<W, I> Iterator for FileWriter<W, I>
where
W: Write,
I: FallibleStreamingIterator<Item = [u8], Error = Error>,
{
type Item = Result<(), Error>;
fn next(&mut self) -> Option<Self::Item> {
let item = self.iterator.next().transpose()?;
Some(item.and_then(|x| {
self.writer.write_all(x)?;
Ok(())
}))
}
}