Initial commit

src/lib.rs

+#![feature(libc)]
+extern crate libc;
+
+use std::mem;
+use self::libc::{c_int, c_uint, c_ushort, c_uchar, STDOUT_FILENO};
+use self::libc::ioctl;
+
+use std::io::{Write, Result as IoResult};
+
+extern {
+    static tiocgwinsz: c_int;
+
+    fn tcgetattr(filedes: c_int, termptr: *mut Termios) -> c_int;
+    fn tcsetattr(filedes: c_int, opt: c_int, termptr: *mut Termios) -> c_int;
+    fn cfmakeraw(termptr: *mut Termios);
+}
+
+#[repr(C)]
+struct TermSize {
+    row: c_ushort,
+    col: c_ushort,
+    _x: c_ushort,
+    _y: c_ushort,
+}
+
+/// Get the size of the terminal. If the program isn't running in a terminal, it will return
+/// `None`.
+pub fn termsize() -> Option<(usize, usize)> {
+    unsafe {
+        let mut size: TermSize = mem::zeroed();
+
+        if ioctl(STDOUT_FILENO, tiocgwinsz as u64, &mut size as *mut _) == 0 {
+            Some((size.col as usize, size.row as usize))
+        } else {
+            None
+        }
+    }
+}
+
+#[derive(Clone)]
+#[repr(C)]
+struct Termios {
+    c_iflag: c_uint,
+    c_oflag: c_uint,
+    c_cflag: c_uint,
+    c_lflag: c_uint,
+    c_line: c_uchar,
+    c_cc: [c_uchar; 32],
+    c_ispeed: c_uint,
+    c_ospeed: c_uint,
+}
+
+fn get_terminal_attr() -> (Termios, c_int) {
+    unsafe {
+        let mut ios = Termios {
+            c_iflag: 0,
+            c_oflag: 0,
+            c_cflag: 0,
+            c_lflag: 0,
+            c_line: 0,
+            c_cc: [0; 32],
+            c_ispeed: 0,
+            c_ospeed: 0
+        };
+
+        let attr = tcgetattr(0, &mut ios);
+        (ios, attr)
+    }
+}
+
+fn make_raw(ios: &mut Termios) {
+    unsafe {
+        cfmakeraw(&mut *ios);
+    }
+}
+
+fn set_terminal_attr(ios: *mut Termios) -> c_int {
+    unsafe {
+        tcsetattr(0, 0, ios)
+    }
+}
+
+/// A terminal restorer, which keeps the previous state of the terminal, and restores it, when
+/// dropped.
+pub struct TerminalRestorer {
+    prev_ios: Termios
+}
+
+impl Drop for TerminalRestorer {
+    fn drop(&mut self) {
+        set_terminal_attr(&mut self.prev_ios as *mut _);
+    }
+}
+
+/// Switch to raw mode.
+///
+/// Raw mode means that stdin won't be printed (it will instead have to be written manually by the
+/// program). Furthermore, the input isn't canonicalised or buffered (that is, you can read from
+/// stdin one byte of a time). The output is neither modified in any way.
+///
+/// Panics
+/// ------
+///
+/// This may panic if the Termios settings can be set or loaded properly.
+pub fn raw_mode() -> TerminalRestorer {
+    let (mut ios, err) = get_terminal_attr();
+    let prev_ios = ios.clone();
+    if err != 0 {
+        panic!("Failed to load termios settings properly.");
+    }
+
+    make_raw(&mut ios);
+
+    if set_terminal_attr(&mut ios as *mut _) != 0 {
+        panic!("Failed to init termios raw mode properly.");
+    }
+
+    TerminalRestorer {
+        prev_ios: prev_ios,
+    }
+}
+
+/// Controlling terminals.
+pub trait TermControl {
+    /// Print the CSI (control sequence introducer) followed by a byte string.
+    fn csi(&mut self, b: &[u8]) -> IoResult<usize>;
+    /// Clear the terminal.
+    fn clear(&mut self) -> IoResult<usize> {
+        self.csi(b"2J")
+    }
+    /// Show the cursor.
+    fn show(&mut self) -> IoResult<usize> {
+        self.csi(b"?25h")
+    }
+    /// Hide the cursor.
+    fn hide(&mut self) -> IoResult<usize> {
+        self.csi(b"?25l")
+    }
+    /// Reset the style of the cursor.
+    fn reset_style(&mut self) -> IoResult<usize> {
+        self.csi(b"0m")
+    }
+    /// Go to a given position.
+    fn goto(&mut self, x: usize, y: usize) -> IoResult<usize> {
+        self.csi(format!("{};{}H", x, y).as_bytes())
+    }
+}
+
+impl<W: Write> TermControl for W {
+    fn csi(&mut self, b: &[u8]) -> IoResult<usize> {
+        self.write(b"\x1b[").and_then(|x| {
+            self.write(b).map(|y| x + y)
+        })
+    }
+}