Expose is_raw_mode_enabled() function (#592)

src/terminal.rs

@@ -98,6 +98,21 @@ use crate::{csi, impl_display, Result};
 
 pub(crate) mod sys;
 
+/// Tells whether the raw mode is enabled.
+///
+/// Please have a look at the [raw mode](./#raw-mode) section.
+pub fn is_raw_mode_enabled() -> Result<bool> {
+    #[cfg(unix)]
+    {
+        Ok(sys::is_raw_mode_enabled())
+    }
+
+    #[cfg(windows)]
+    {
+        sys::is_raw_mode_enabled()
+    }
+}
+
 /// Enables raw mode.
 ///
 /// Please have a look at the [raw mode](./#raw-mode) section.
@@ -372,7 +387,7 @@ mod tests {
 
     use crate::execute;
 
-    use super::{size, SetSize};
+    use super::*;
 
     // Test is disabled, because it's failing on Travis CI
     #[test]
@@ -395,4 +410,29 @@ mod tests {
 
         assert_eq!((width, height), size().unwrap());
     }
+
+    #[test]
+    fn test_raw_mode() {
+        // check we start from normal mode (may fail on some test harnesses)
+        assert_eq!(is_raw_mode_enabled().unwrap(), false);
+
+        // enable the raw mode
+        enable_raw_mode().unwrap();
+
+        // check it worked (on unix it doesn't really check the underlying
+        // tty but rather check that the code is consistent)
+        assert_eq!(is_raw_mode_enabled().unwrap(), true);
+
+        // enable it again, this should not change anything
+        enable_raw_mode().unwrap();
+
+        // check we're still in raw mode
+        assert_eq!(is_raw_mode_enabled().unwrap(), true);
+
+        // now let's disable it
+        disable_raw_mode().unwrap();
+
+        // check we're back to normal mode
+        assert_eq!(is_raw_mode_enabled().unwrap(), false);
+    }
 }

src/terminal/sys.rs

@@ -4,8 +4,8 @@
 pub(crate) use self::unix::{disable_raw_mode, enable_raw_mode, is_raw_mode_enabled, size};
 #[cfg(windows)]
 pub(crate) use self::windows::{
-    clear, disable_raw_mode, enable_raw_mode, scroll_down, scroll_up, set_size, set_window_title,
-    size,
+    clear, disable_raw_mode, enable_raw_mode, is_raw_mode_enabled, scroll_down, scroll_up,
+    set_size, set_window_title, size,
 };
 
 #[cfg(windows)]

src/terminal/sys/unix.rs

@@ -67,6 +67,11 @@ pub(crate) fn enable_raw_mode() -> Result<()> {
     Ok(())
 }
 
+/// Reset the raw mode.
+///
+/// More precisely, reset the whole termios mode to what it was before the first call
+/// to [enable_raw_mode]. If you don't mess with termios outside of crossterm, it's
+/// effectively disabling the raw mode and doing nothing else.
 pub(crate) fn disable_raw_mode() -> Result<()> {
     let mut original_mode = TERMINAL_MODE_PRIOR_RAW_MODE.lock();
 

src/terminal/sys/windows.rs

@@ -11,14 +11,26 @@ use winapi::{
 
 use crate::{cursor, terminal::ClearType, ErrorKind, Result};
 
-const RAW_MODE_MASK: DWORD = ENABLE_LINE_INPUT | ENABLE_ECHO_INPUT | ENABLE_PROCESSED_INPUT;
+/// bits which can't be set in raw mode
+const NOT_RAW_MODE_MASK: DWORD = ENABLE_LINE_INPUT | ENABLE_ECHO_INPUT | ENABLE_PROCESSED_INPUT;
+
+pub(crate) fn is_raw_mode_enabled() -> Result<bool> {
+    let console_mode = ConsoleMode::from(Handle::current_in_handle()?);
+
+    let dw_mode = console_mode.mode()?;
+
+    Ok(
+        // check none of the "not raw" bits is set
+        dw_mode & NOT_RAW_MODE_MASK == 0,
+    )
+}
 
 pub(crate) fn enable_raw_mode() -> Result<()> {
     let console_mode = ConsoleMode::from(Handle::current_in_handle()?);
 
     let dw_mode = console_mode.mode()?;
 
-    let new_mode = dw_mode & !RAW_MODE_MASK;
+    let new_mode = dw_mode & !NOT_RAW_MODE_MASK;
 
     console_mode.set_mode(new_mode)?;
 
@@ -30,7 +42,7 @@ pub(crate) fn disable_raw_mode() -> Result<()> {
 
     let dw_mode = console_mode.mode()?;
 
-    let new_mode = dw_mode | RAW_MODE_MASK;
+    let new_mode = dw_mode | NOT_RAW_MODE_MASK;
 
     console_mode.set_mode(new_mode)?;