73 lines
1.9 KiB
Rust
73 lines
1.9 KiB
Rust
#![cfg(any(target_family = "unix", target_family = "windows"))]
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use std::fs::File;
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use std::io::{Read, Write};
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mod common;
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#[cfg(windows)]
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use std::os::windows::io::OwnedHandle;
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#[cfg(unix)]
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use std::os::fd::OwnedFd;
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#[cfg(unix)]
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fn switch_stdout_to(file: OwnedFd) -> OwnedFd {
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use std::os::unix::prelude::*;
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extern "C" {
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fn dup(old: i32) -> i32;
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fn dup2(old: i32, new: i32) -> i32;
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}
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unsafe {
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let orig_fd = dup(1);
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assert_ne!(orig_fd, -1);
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let res = OwnedFd::from_raw_fd(orig_fd);
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assert_eq!(dup2(file.as_raw_fd(), 1), 1);
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res
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}
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}
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#[cfg(windows)]
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fn switch_stdout_to(file: OwnedHandle) -> OwnedHandle {
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use std::os::windows::prelude::*;
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extern "system" {
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fn GetStdHandle(nStdHandle: u32) -> *mut u8;
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fn SetStdHandle(nStdHandle: u32, handle: *mut u8) -> i32;
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}
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const STD_OUTPUT_HANDLE: u32 = (-11i32) as u32;
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const INVALID_HANDLE_VALUE: *mut u8 = !0 as *mut u8;
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unsafe {
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let orig_hdl = GetStdHandle(STD_OUTPUT_HANDLE);
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assert!(!orig_hdl.is_null() && orig_hdl != INVALID_HANDLE_VALUE);
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let rc = SetStdHandle(STD_OUTPUT_HANDLE, file.into_raw_handle() as *mut _);
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assert!(rc != 0);
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OwnedHandle::from_raw_handle(orig_hdl as _)
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}
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}
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#[test]
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#[cfg_attr(miri, ignore)] // dup/SetStdHandle not supported by Miri
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fn switch_stdout() {
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let temp = common::tmpdir();
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let path = temp.join("switch-stdout-output");
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let f = File::create(&path).unwrap();
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let mut stdout = std::io::stdout();
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stdout.write(b"foo\n").unwrap();
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stdout.flush().unwrap();
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let orig_hdl = switch_stdout_to(f.into());
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stdout.write(b"bar\n").unwrap();
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stdout.flush().unwrap();
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switch_stdout_to(orig_hdl);
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let mut contents = String::new();
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File::open(&path).unwrap().read_to_string(&mut contents).unwrap();
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assert_eq!(contents, "bar\n");
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}
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