evobench_tools/utillib/
ndjson_pipe.rs

1use std::{
2    io::{BufRead, BufReader, PipeReader, PipeWriter, Write, pipe},
3    marker::PhantomData,
4};
5
6use anyhow::Result;
7use serde::{Serialize, de::DeserializeOwned};
8
9pub struct NdJsonPipe<T: Serialize + DeserializeOwned> {
10    _phantom: PhantomData<fn() -> T>,
11    p: (PipeReader, PipeWriter),
12}
13
14#[derive(Debug)]
15pub struct NdJsonPipeWriter<T: Serialize + DeserializeOwned> {
16    _phantom: PhantomData<fn() -> T>,
17    w: PipeWriter,
18}
19
20impl<T: Serialize + DeserializeOwned> NdJsonPipeWriter<T> {
21    /// Immediately sends `msg` to the daemon process (there is no
22    /// buffering).
23    pub fn send(&mut self, msg: T) -> Result<()> {
24        let mut s = serde_json::to_string(&msg)?;
25        s.push('\n');
26        self.w.write_all(s.as_bytes())?;
27        Ok(())
28    }
29}
30
31#[derive(Debug)]
32pub struct NdJsonPipeReader<T: Serialize + DeserializeOwned> {
33    _phantom: PhantomData<fn() -> T>,
34    line: String,
35    reader: BufReader<PipeReader>,
36}
37
38impl<T: Serialize + DeserializeOwned> Iterator for NdJsonPipeReader<T> {
39    type Item = Result<T>;
40
41    fn next(&mut self) -> Option<Self::Item> {
42        (|| -> Result<Option<T>> {
43            let nread = self.reader.read_line(&mut self.line)?;
44            if nread == 0 {
45                Ok(None)
46            } else {
47                let val: T = serde_json::from_str(&self.line)?;
48                self.line.clear();
49                Ok(Some(val))
50            }
51        })()
52        .transpose()
53    }
54}
55
56impl<T: Serialize + DeserializeOwned> NdJsonPipe<T> {
57    pub fn new() -> Result<Self> {
58        let p = pipe()?;
59        Ok(Self {
60            _phantom: PhantomData,
61            p,
62        })
63    }
64
65    /// Note: if the borrow checker doesn't allow you to use both
66    /// `into_*` methods, then revert the git commit introducing this
67    /// comment.
68    pub fn into_reader(self) -> NdJsonPipeReader<T> {
69        let (r, _w) = self.p;
70        NdJsonPipeReader {
71            _phantom: PhantomData,
72            line: String::new(),
73            reader: BufReader::new(r),
74        }
75    }
76
77    /// Note: if the borrow checker doesn't allow you to use both
78    /// `into_*` methods, then revert the git commit introducing this
79    /// comment.
80    pub fn into_writer(self) -> NdJsonPipeWriter<T> {
81        let (_r, w) = self.p;
82        NdJsonPipeWriter {
83            _phantom: PhantomData,
84            w,
85        }
86    }
87}
evobench_tools/utillib/ndjson_pipe.rs

evobench_tools/utillib/
ndjson_pipe.rs
