byteor_adapters/
line.rs

1use std::io::{BufRead, Write};
2
3use crate::{Adapter, AdapterError, EgressAdapter, IngressAdapter};
4
5/// A simple line-delimited ingress adapter.
6///
7/// Each call to [`IngressAdapter::read_next`] reads one line, strips the trailing `\n` (and
8/// optional `\r`), and copies it into the provided output buffer.
9pub struct LineIngress<R> {
10    name: String,
11    inner: R,
12    scratch: Vec<u8>,
13}
14
15impl<R> LineIngress<R> {
16    /// Create a line-delimited ingress adapter.
17    pub fn new(name: impl Into<String>, inner: R) -> Self {
18        Self {
19            name: name.into(),
20            inner,
21            scratch: Vec::with_capacity(1024),
22        }
23    }
24
25    fn trim_line(mut line: &[u8]) -> &[u8] {
26        if let Some(stripped) = line.strip_suffix(b"\n") {
27            line = stripped;
28        }
29        if let Some(stripped) = line.strip_suffix(b"\r") {
30            line = stripped;
31        }
32        line
33    }
34}
35
36impl<R> Adapter for LineIngress<R> {
37    fn name(&self) -> &str {
38        &self.name
39    }
40
41    fn transport_kind(&self) -> &str {
42        "line"
43    }
44}
45
46impl<R: BufRead> IngressAdapter for LineIngress<R> {
47    fn read_next(&mut self, out: &mut [u8]) -> Result<Option<usize>, AdapterError> {
48        self.scratch.clear();
49
50        let n = self
51            .inner
52            .read_until(b'\n', &mut self.scratch)
53            .map_err(|e| AdapterError::Io {
54                op: "read_until",
55                source: e,
56            })?;
57
58        if n == 0 {
59            return Ok(None);
60        }
61
62        let line = Self::trim_line(&self.scratch);
63        let n = line.len().min(out.len());
64        out[..n].copy_from_slice(&line[..n]);
65        Ok(Some(n))
66    }
67}
68
69/// A simple egress adapter that writes messages to a `Write` target.
70///
71/// This is line-oriented by default: it writes `msg` followed by `\n`.
72pub struct LineEgress<W> {
73    name: String,
74    inner: W,
75}
76
77impl<W> LineEgress<W> {
78    /// Create a line-delimited egress adapter.
79    pub fn new(name: impl Into<String>, inner: W) -> Self {
80        Self {
81            name: name.into(),
82            inner,
83        }
84    }
85}
86
87impl<W> Adapter for LineEgress<W> {
88    fn name(&self) -> &str {
89        &self.name
90    }
91
92    fn transport_kind(&self) -> &str {
93        "line"
94    }
95}
96
97impl<W: Write> EgressAdapter for LineEgress<W> {
98    fn write_msg(&mut self, msg: &[u8]) -> Result<(), AdapterError> {
99        self.inner.write_all(msg).map_err(|e| AdapterError::Io {
100            op: "write_all",
101            source: e,
102        })?;
103        self.inner.write_all(b"\n").map_err(|e| AdapterError::Io {
104            op: "write_newline",
105            source: e,
106        })?;
107        Ok(())
108    }
109
110    fn flush(&mut self) -> Result<(), AdapterError> {
111        self.inner.flush().map_err(|e| AdapterError::Io {
112            op: "flush",
113            source: e,
114        })
115    }
116}
byteor_adapters/line.rs

byteor_adapters/
line.rs
