bp3d_os/shell/os/
unix.rs

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28
29use std::cell::Cell;
30use std::mem::MaybeUninit;
31
32/// Represents an interactive terminal.
33pub struct Terminal {
34    attrs: libc::termios,
35}
36
37impl Terminal {
38    /// Creates a new instance of an interactive terminal.
39    ///
40    /// This function automatically sets-up the current OS terminal for interactive input and resets
41    /// it back on drop automatically.
42    pub fn new() -> Self {
43        let mut attrs = MaybeUninit::<libc::termios>::uninit();
44        unsafe {
45            libc::tcgetattr(0, attrs.as_mut_ptr());
46            let mut newattrs = attrs.assume_init();
47            newattrs.c_lflag &= !(libc::ICANON | libc::ECHO);
48            libc::tcsetattr(0, libc::TCSANOW, &newattrs);
49            Terminal {
50                attrs: attrs.assume_init(),
51            }
52        }
53    }
54}
55
56impl Drop for Terminal {
57    fn drop(&mut self) {
58        unsafe {
59            libc::tcsetattr(0, libc::TCSANOW, &self.attrs);
60        }
61    }
62}
63
64/// Writes the given string immediately (unbuffered).
65pub fn write(str: &str) {
66    unsafe {
67        libc::write(1, str.as_bytes().as_ptr() as _, str.len());
68    }
69}
70
71/// Returns a tuple with respectively the maximum number of columns and rows available in the
72/// terminal.
73///
74/// This function issues a syscall each time it is invoked.
75pub fn get_window_size() -> (i32, i32) {
76    let mut sz = std::mem::MaybeUninit::<libc::winsize>::uninit();
77    unsafe {
78        libc::ioctl(1, libc::TIOCGWINSZ, sz.as_mut_ptr());
79        (sz.assume_init().ws_col as _, sz.assume_init().ws_row as _)
80    }
81}
82
83thread_local! {
84    static HEIGHT: Cell<i32> = const { Cell::new(-1) };
85}
86
87/// Returns the maximum number of rows available in the terminal.
88///
89/// This function amortizes the cost of the syscall by only issuing it once for the current thread.
90pub fn get_window_height_amortized() -> i32 {
91    if HEIGHT.get() == -1 {
92        let mut sz = std::mem::MaybeUninit::<libc::winsize>::uninit();
93        unsafe {
94            libc::ioctl(1, libc::TIOCGWINSZ, sz.as_mut_ptr());
95            HEIGHT.set(sz.assume_init().ws_row as _);
96        }
97    }
98    HEIGHT.get()
99}
bp3d_os/shell/os/unix.rs

bp3d_os/shell/os/
unix.rs
