refactor(test/libc-pipe): replace unsafe read with safe read_into_slice

Author: hulxv

tests/pass-dep/libc/libc-pipe.rs

@@ -38,13 +38,11 @@ fn test_pipe() {
     let data = b"123";
     write_all_from_slice(fds[1], data).unwrap();
     let mut buf4: [u8; 5] = [0; 5];
-    let res = unsafe { libc::read(fds[0], buf4.as_mut_ptr().cast(), buf4.len() as libc::size_t) };
-    assert!(res > 0 && res <= 3);
-    let res = res as usize;
+    let res = read_into_slice(fds[0], &mut buf4).unwrap().0.len();
     assert_eq!(buf4[..res], data[..res]);
     if res < 3 {
         // Drain the rest from the read end.
-        let res = unsafe { libc_utils::read_all(fds[0], buf4[res..].as_mut_ptr().cast(), 3 - res) };
+        let res = read_into_slice(fds[0], &mut buf4[res..]).unwrap().0.len();
         assert!(res > 0);
     }
 }
@@ -64,8 +62,7 @@ fn test_pipe_threaded() {
     // Read and write from different direction
     let thread2 = thread::spawn(move || {
         thread::yield_now();
-        let data = b"12345";
-        write_all_from_slice(fds[1], data).unwrap();
+        write_all_from_slice(fds[1], b"12345").unwrap();
     });
     let buf = read_all_into_array::<5>(fds[0]).unwrap();
     assert_eq!(&buf, b"12345");
@@ -87,8 +84,7 @@ fn test_race() {
         unsafe { assert_eq!(VAL, 1) };
     });
     unsafe { VAL = 1 };
-    let data = b"a";
-    write_all_from_slice(fds[1], data).unwrap();
+    write_all_from_slice(fds[1], b"a").unwrap();
     thread::yield_now();
     thread1.join().unwrap();
 }
@@ -176,8 +172,7 @@ fn test_pipe_fcntl_threaded() {
         // The write below will unblock the `read` in main thread: even though
         // the socket is now "non-blocking", the shim needs to deal correctly
         // with threads that were blocked before the socket was made non-blocking.
-        let data = b"abcde";
-        write_all_from_slice(fds[1], data).unwrap();
+        write_all_from_slice(fds[1], b"abcde").unwrap();
     });
     // The `read` below will block.
     let buf = read_all_into_array::<5>(fds[0]).unwrap();

tests/utils/libc.rs

@@ -53,10 +53,7 @@ pub fn read_all_into_array<const N: usize>(fd: libc::c_int) -> Result<[u8; N], l
     }
 }
 
-pub fn read_all_into_slice(
-    fd: libc::c_int,
-    buf: &mut [u8],
-) -> Result<(), libc::ssize_t> {
+pub fn read_all_into_slice(fd: libc::c_int, buf: &mut [u8]) -> Result<(), libc::ssize_t> {
     let res = unsafe { read_all(fd, buf.as_mut_ptr().cast(), buf.len()) };
     if res >= 0 {
         assert_eq!(res as usize, buf.len());
@@ -70,12 +67,8 @@ pub fn read_into_slice(
     fd: libc::c_int,
     buf: &mut [u8],
 ) -> Result<(&mut [u8], &mut [u8]), libc::ssize_t> {
-    let res = unsafe { read_all(fd, buf.as_mut_ptr().cast(), buf.len()) };
-    if res >= 0 {
-        Ok(buf.split_at_mut(res as usize))
-    } else {
-        Err(res)
-    }
+    let res = unsafe { libc::read(fd, buf.as_mut_ptr().cast(), buf.len()) };
+    if res >= 0 { Ok(buf.split_at_mut(res as usize)) } else { Err(res) }
 }
 
 pub unsafe fn write_all(