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//! NullStream — discards all data. Write-only PES sink. For benchmarking.
use crate::disc::DiscTitle;
use std::io;
/// Null stream — accepts PES writes, discards data. For benchmarking rip speed.
pub struct NullStream {
disc_title: DiscTitle,
}
impl NullStream {
pub fn new(title: &DiscTitle) -> Self {
Self {
disc_title: title.clone(),
}
}
}
impl crate::pes::Stream for NullStream {
fn read(&mut self) -> io::Result<Option<crate::pes::PesFrame>> {
// Write-only sink: per the Stream trait contract, read() on a
// write-opened stream returns StreamWriteOnly. Returning Ok(None)
// would be misread as a legitimate empty stream.
Err(crate::error::Error::StreamWriteOnly.into())
}
fn write(&mut self, _: &crate::pes::PesFrame) -> io::Result<()> {
Ok(())
}
fn finish(&mut self) -> io::Result<()> {
Ok(())
}
fn info(&self) -> &DiscTitle {
&self.disc_title
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::pes::Stream;
/// Verify NullStream routes through the `Stream` trait object cleanly.
#[test]
fn stream_via_dyn_object_writes_and_finishes() {
let title = DiscTitle::empty();
let mut sink: Box<dyn Stream> = Box::new(NullStream::new(&title));
let frame = crate::pes::PesFrame {
track: 0,
pts: 0,
keyframe: true,
data: vec![0x01, 0x02, 0x03],
duration_ns: None,
};
sink.write(&frame).unwrap();
let _ = sink.info();
sink.finish().unwrap();
}
/// read() on the write-only NullStream must return StreamWriteOnly,
/// not Ok(None) (which a caller would misread as an empty stream).
#[test]
fn read_returns_write_only_error() {
let title = DiscTitle::empty();
let mut sink = NullStream::new(&title);
let err = Stream::read(&mut sink).expect_err("read on a sink must error");
assert_eq!(err.kind(), io::ErrorKind::Unsupported);
}
/// finish() must be idempotent and safe to call repeatedly — a benchmark
/// driver may finish more than once. Each must be Ok(()), and writes
/// after finish must still succeed (NullStream has no terminal state).
#[test]
fn finish_is_idempotent_and_write_after_finish_ok() {
let title = DiscTitle::empty();
let mut sink = NullStream::new(&title);
sink.finish().unwrap();
sink.finish().unwrap();
let frame = crate::pes::PesFrame {
track: 3,
pts: 42,
keyframe: false,
data: vec![0xFF; 4096],
duration_ns: Some(1000),
};
// Discard-sink contract: write always returns Ok regardless of frame
// size, track index, or post-finish state.
sink.write(&frame).unwrap();
}
}