pipes.rs: simplify trait and match

src/uucore/src/lib/features/pipes.rs

@@ -8,10 +8,9 @@
 #[cfg(any(target_os = "linux", target_os = "android"))]
 use rustix::pipe::{SpliceFlags, fcntl_setpipe_size};
 #[cfg(any(target_os = "linux", target_os = "android"))]
-use std::fs::File;
-#[cfg(any(target_os = "linux", target_os = "android"))]
 use std::{
-    io::{Read, Write},
+    fs::File,
+    io::{PipeReader, PipeWriter, Read, Write},
     os::fd::AsFd,
     sync::OnceLock,
 };
@@ -27,19 +26,17 @@ const KERNEL_DEFAULT_PIPE_SIZE: usize = 64 * 1024;
 /// used for resolving the limitation for splice: one of a input or output should be pipe
 #[inline]
 #[cfg(any(target_os = "linux", target_os = "android"))]
-pub fn pipe<const SIZE_REQUIRED: bool>(
-    s: usize,
-) -> std::io::Result<(std::io::PipeReader, std::io::PipeWriter)> {
-    let (read, write) = std::io::pipe()?;
+pub fn pipe<const SIZE_REQUIRED: bool>(s: usize) -> std::io::Result<(PipeReader, PipeWriter)> {
+    let pair = std::io::pipe()?;
     // guard unnecessary syscall
     if s > KERNEL_DEFAULT_PIPE_SIZE {
-        let r = fcntl_setpipe_size(&read, s);
+        let r = fcntl_setpipe_size(&pair.0, s);
         if SIZE_REQUIRED {
             r?;
         }
     }
 
-    Ok((read, write))
+    Ok(pair)
 }
 
 /// Less noisy wrapper around [`rustix::pipe::splice`].
@@ -87,11 +84,7 @@ pub fn might_fuse(source: &impl AsFd) -> bool {
 /// fails if one of in/output should be pipe
 #[inline]
 #[cfg(any(target_os = "linux", target_os = "android"))]
-pub fn splice_unbounded<R, S>(source: &R, dest: &mut S) -> std::io::Result<bool>
-where
-    R: Read + AsFd,
-    S: AsFd,
-{
+pub fn splice_unbounded(source: &impl AsFd, dest: &mut impl AsFd) -> std::io::Result<bool> {
     // improve throughput
     // todo: avoid fcntl overhead for small input, but don't fcntl inside of the loop
     // no need to increase pipe size of input fd since
@@ -118,8 +111,7 @@ where
     R: Read + AsFd,
     S: AsFd,
 {
-    static PIPE_CACHE: OnceLock<Option<(std::io::PipeReader, std::io::PipeWriter)>> =
-        OnceLock::new();
+    static PIPE_CACHE: OnceLock<Option<(PipeReader, PipeWriter)>> = OnceLock::new();
     let Some((pipe_rd, pipe_wr)) = PIPE_CACHE
         .get_or_init(|| pipe::<false>(MAX_ROOTLESS_PIPE_SIZE).ok())
         .as_ref()
@@ -163,8 +155,7 @@ pub fn send_n_bytes(
     mut target: impl Write + AsFd,
     n: u64,
 ) -> std::io::Result<u64> {
-    static PIPE_CACHE: OnceLock<Option<(std::io::PipeReader, std::io::PipeWriter)>> =
-        OnceLock::new();
+    static PIPE_CACHE: OnceLock<Option<(PipeReader, PipeWriter)>> = OnceLock::new();
     let pipe_size = MAX_ROOTLESS_PIPE_SIZE.min(n as usize);
     let mut n = n;
     let mut bytes_written: u64 = 0;
@@ -187,7 +178,7 @@ pub fn send_n_bytes(
         loop {
             match splice(&input, &target, n as usize) {
                 Ok(0) => break might_fuse(&input),
-                Ok(s @ 1..) => {
+                Ok(s) => {
                     n -= s as u64;
                     bytes_written += s as u64;
                 }
@@ -202,7 +193,7 @@ pub fn send_n_bytes(
         loop {
             match splice(&input, &broker_w, n as usize) {
                 Ok(0) => break might_fuse(&input),
-                Ok(s @ 1..) => {
+                Ok(s) => {
                     if splice_exact(&broker_r, &target, s).is_ok() {
                         n -= s as u64;
                         bytes_written += s as u64;