unix: Allow changing any fd to raw mode

As discussed in crossterm-rs/crossterm#188,
the terminal might not be stdin.

Signed-off-by: Anders Kaseorg <andersk@mit.edu>

src/sys/unix.rs

@@ -1,10 +1,12 @@
 //! This module contains all `unix` specific terminal related logic.
 
+use std::collections::HashMap;
+use std::os::unix::io::{AsRawFd, RawFd};
 use std::sync::Mutex;
 use std::{io, mem};
 
 pub use libc::termios as Termios;
-use libc::{cfmakeraw, tcgetattr, tcsetattr, STDIN_FILENO, TCSANOW};
+use libc::{cfmakeraw, tcgetattr, tcsetattr, TCSANOW};
 
 use lazy_static::lazy_static;
 
@@ -13,11 +15,14 @@ use crate::{ErrorKind, Result};
 lazy_static! {
     // Some(Termios) -> we're in the raw mode and this is the previous mode
     // None -> we're not in the raw mode
-    static ref TERMINAL_MODE_PRIOR_RAW_MODE: Mutex<Option<Termios>> = Mutex::new(None);
+    static ref TERMINAL_MODE_PRIOR_RAW_MODE: Mutex<HashMap<RawFd, Termios>> = Mutex::new(HashMap::new());
 }
 
-pub fn is_raw_mode_enabled() -> bool {
-    TERMINAL_MODE_PRIOR_RAW_MODE.lock().unwrap().is_some()
+pub fn is_raw_mode_enabled(file: &impl AsRawFd) -> bool {
+    TERMINAL_MODE_PRIOR_RAW_MODE
+        .lock()
+        .unwrap()
+        .contains_key(&file.as_raw_fd())
 }
 
 fn wrap_with_result(t: i32) -> Result<()> {
@@ -33,44 +38,44 @@ pub fn raw_terminal_attr(termios: &mut Termios) {
     unsafe { cfmakeraw(termios) }
 }
 
-pub fn get_terminal_attr() -> Result<Termios> {
+pub fn get_terminal_attr(file: &impl AsRawFd) -> Result<Termios> {
     unsafe {
         let mut termios = mem::zeroed();
-        wrap_with_result(tcgetattr(STDIN_FILENO, &mut termios))?;
+        wrap_with_result(tcgetattr(file.as_raw_fd(), &mut termios))?;
         Ok(termios)
     }
 }
 
-pub fn set_terminal_attr(termios: &Termios) -> Result<()> {
-    wrap_with_result(unsafe { tcsetattr(STDIN_FILENO, TCSANOW, termios) })
+pub fn set_terminal_attr(file: &mut impl AsRawFd, termios: &Termios) -> Result<()> {
+    wrap_with_result(unsafe { tcsetattr(file.as_raw_fd(), TCSANOW, termios) })
 }
 
-pub fn enable_raw_mode() -> Result<()> {
+pub fn enable_raw_mode(file: &mut impl AsRawFd) -> Result<()> {
     let mut original_mode = TERMINAL_MODE_PRIOR_RAW_MODE.lock().unwrap();
 
-    if original_mode.is_some() {
+    if original_mode.contains_key(&file.as_raw_fd()) {
         return Ok(());
     }
 
-    let mut ios = get_terminal_attr()?;
+    let mut ios = get_terminal_attr(file)?;
     let original_mode_ios = ios;
 
     raw_terminal_attr(&mut ios);
-    set_terminal_attr(&ios)?;
+    set_terminal_attr(file, &ios)?;
 
     // Keep it last - set the original mode only if we were able to switch to the raw mode
-    *original_mode = Some(original_mode_ios);
+    original_mode.insert(file.as_raw_fd(), original_mode_ios);
 
     Ok(())
 }
 
-pub fn disable_raw_mode() -> Result<()> {
+pub fn disable_raw_mode(file: &mut impl AsRawFd) -> Result<()> {
     let mut original_mode = TERMINAL_MODE_PRIOR_RAW_MODE.lock().unwrap();
 
-    if let Some(original_mode_ios) = original_mode.as_ref() {
-        set_terminal_attr(original_mode_ios)?;
+    if let Some(original_mode_ios) = original_mode.get(&file.as_raw_fd()) {
+        set_terminal_attr(file, original_mode_ios)?;
         // Keep it last - remove the original mode only if we were able to switch back
-        *original_mode = None;
+        original_mode.remove(&file.as_raw_fd());
     }
 
     Ok(())