use super::file_descriptor::FileDescriptor; use libc; use std::io::BufReader; use std::io::Read; // A struct to hold the references to the base stdout and the captured one pub struct StdioCapturer { stdout_backup: libc::c_int, stderr_backup: libc::c_int, stdout_reader: libc::c_int, stderr_reader: libc::c_int, } #[cfg(not(target_os = "windows"))] use libc::{STDERR_FILENO, STDOUT_FILENO}; #[cfg(target_os = "windows")] const _STDIN_FILENO: libc::c_int = 0; #[cfg(target_os = "windows")] const STDOUT_FILENO: libc::c_int = 1; #[cfg(target_os = "windows")] const STDERR_FILENO: libc::c_int = 2; // Implementation inspired in // https://github.com/rust-lang/rust/blob/7d52cbce6db83e4fc2d8706b4e4b9c7da76cbcf8/src/test/run-pass/issues/issue-30490.rs // Currently only works in Unix systems (Mac, Linux) impl StdioCapturer { fn pipe() -> (libc::c_int, libc::c_int) { let mut fds = [0; 2]; #[cfg(not(target_os = "windows"))] assert_eq!(unsafe { libc::pipe(fds.as_mut_ptr()) }, 0); #[cfg(target_os = "windows")] assert_eq!( unsafe { libc::pipe(fds.as_mut_ptr(), 1000, libc::O_TEXT) }, 0 ); (fds[0], fds[1]) } pub fn new() -> Self { let stdout_backup = unsafe { libc::dup(STDOUT_FILENO) }; let stderr_backup = unsafe { libc::dup(STDERR_FILENO) }; let (stdout_reader, stdout_writer) = Self::pipe(); let (stderr_reader, stderr_writer) = Self::pipe(); assert!(unsafe { libc::dup2(stdout_writer, STDOUT_FILENO) } > -1); assert!(unsafe { libc::dup2(stderr_writer, STDERR_FILENO) } > -1); // Make sure we close any duplicates of the writer end of the pipe, // otherwise we can get stuck reading from the pipe which has open // writers but no one supplying any input assert_eq!(unsafe { libc::close(stdout_writer) }, 0); assert_eq!(unsafe { libc::close(stderr_writer) }, 0); StdioCapturer { stdout_backup, stderr_backup, stdout_reader, stderr_reader, } } pub fn end(self) -> Result<(String, String), std::io::Error> { // The Stdio passed into the Command took over (and closed) std{out, err} // so we should restore them as they were. assert!(unsafe { libc::dup2(self.stdout_backup, STDOUT_FILENO) } > -1); assert!(unsafe { libc::dup2(self.stderr_backup, STDERR_FILENO) } > -1); let fd = FileDescriptor::new(self.stdout_reader); let mut reader = BufReader::new(fd); let mut stdout_read = "".to_string(); let _ = reader.read_to_string(&mut stdout_read)?; let fd = FileDescriptor::new(self.stderr_reader); let mut reader = BufReader::new(fd); let mut stderr_read = "".to_string(); let _ = reader.read_to_string(&mut stderr_read)?; Ok((stdout_read, stderr_read)) } }