Change cursor visibility

Author: gwenn

Cargo.toml

@@ -50,7 +50,6 @@ termios = { version = "0.3.3", optional = true }
 
 [target.'cfg(windows)'.dependencies]
 winapi = { version = "0.3", features = ["consoleapi", "handleapi", "synchapi", "minwindef", "processenv", "std", "winbase", "wincon", "winerror", "winuser"] }
-scopeguard = "1.1"
 clipboard-win = "5.0"
 
 [dev-dependencies]

examples/read_password.rs

@@ -14,13 +14,13 @@ impl Highlighter for MaskingHighlighter {
     fn highlight<'l>(&self, line: &'l str, _pos: usize) -> Cow<'l, str> {
         use unicode_width::UnicodeWidthStr;
         if self.masking {
-            Owned("*".repeat(line.width()))
+            Owned(" ".repeat(line.width()))
         } else {
             Borrowed(line)
         }
     }
 
-    fn highlight_char(&self, line: &str, pos: usize, forced: bool) -> bool {
+    fn highlight_char(&self, _line: &str, _pos: usize, _forced: bool) -> bool {
         self.masking
     }
 }
@@ -37,7 +37,9 @@ fn main() -> Result<()> {
     rl.helper_mut().expect("No helper").masking = true;
     rl.set_color_mode(ColorMode::Forced); // force masking
     rl.set_auto_add_history(false); // make sure password is not added to history
+    let mut guard = rl.set_cursor_visibility(false)?;
     let passwd = rl.readline("Password:")?;
+    guard.take();
     println!("Secret: {passwd}");
     Ok(())
 }

src/lib.rs

@@ -917,6 +917,14 @@ impl<H: Helper, I: History> Editor<H, I> {
     pub fn create_external_printer(&mut self) -> Result<<Terminal as Term>::ExternalPrinter> {
         self.term.create_external_printer()
     }
+
+    /// Change cursor visibility
+    pub fn set_cursor_visibility(
+        &mut self,
+        visible: bool,
+    ) -> Result<Option<<Terminal as Term>::CursorGuard>> {
+        self.term.set_cursor_visibility(visible)
+    }
 }
 
 impl<H: Helper, I: History> config::Configurer for Editor<H, I> {

src/tty/mod.rs

@@ -220,6 +220,7 @@ pub trait Term {
     type Writer: Renderer<Reader = Self::Reader>; // rl_outstream
     type Mode: RawMode;
     type ExternalPrinter: ExternalPrinter;
+    type CursorGuard;
 
     fn new(
         color_mode: ColorMode,
@@ -246,6 +247,8 @@ pub trait Term {
     fn writeln(&self) -> Result<()>;
     /// Create an external printer
     fn create_external_printer(&mut self) -> Result<Self::ExternalPrinter>;
+    /// Change cursor visibility
+    fn set_cursor_visibility(&mut self, visible: bool) -> Result<Option<Self::CursorGuard>>;
 }
 
 // If on Windows platform import Windows TTY module

src/tty/test.rs

@@ -160,6 +160,7 @@ pub struct DummyTerminal {
 }
 
 impl Term for DummyTerminal {
+    type CursorGuard = ();
     type ExternalPrinter = DummyExternalPrinter;
     type KeyMap = KeyMap;
     type Mode = Mode;
@@ -219,6 +220,10 @@ impl Term for DummyTerminal {
         Ok(DummyExternalPrinter {})
     }
 
+    fn set_cursor_visibility(&mut self, _: bool) -> Result<Option<()>> {
+        Ok(None)
+    }
+
     fn writeln(&self) -> Result<()> {
         Ok(())
     }

src/tty/unix.rs

@@ -1139,6 +1139,23 @@ fn write_all(fd: RawFd, buf: &str) -> nix::Result<()> {
     Ok(())
 }
 
+pub struct PosixCursorGuard(RawFd);
+
+impl Drop for PosixCursorGuard {
+    fn drop(&mut self) {
+        let _ = set_cursor_visibility(self.0, true);
+    }
+}
+
+fn set_cursor_visibility(fd: RawFd, visible: bool) -> Result<Option<PosixCursorGuard>> {
+    write_all(fd, if visible { "\x1b[?25h" } else { "\x1b[?25l" })?;
+    Ok(if visible {
+        None
+    } else {
+        Some(PosixCursorGuard(fd))
+    })
+}
+
 #[cfg(not(feature = "signal-hook"))]
 static mut SIGWINCH_PIPE: RawFd = -1;
 #[cfg(not(feature = "signal-hook"))]
@@ -1236,6 +1253,7 @@ impl PosixTerminal {
 }
 
 impl Term for PosixTerminal {
+    type CursorGuard = PosixCursorGuard;
     type ExternalPrinter = ExternalPrinter;
     type KeyMap = PosixKeyMap;
     type Mode = PosixMode;
@@ -1405,6 +1423,14 @@ impl Term for PosixTerminal {
             tty_out: self.tty_out,
         })
     }
+
+    fn set_cursor_visibility(&mut self, visible: bool) -> Result<Option<PosixCursorGuard>> {
+        if self.is_out_a_tty {
+            set_cursor_visibility(self.tty_out, visible)
+        } else {
+            Ok(None)
+        }
+    }
 }
 
 #[allow(unused_must_use)]

src/tty/windows.rs

@@ -330,8 +330,8 @@ impl ConsoleRenderer {
         })?)
     }
 
-    fn set_cursor_visible(&mut self, visible: BOOL) -> Result<()> {
-        set_cursor_visible(self.conout, visible)
+    fn set_cursor_visibility(&mut self, visible: bool) -> Result<Option<ConsoleCursorGuard>> {
+        set_cursor_visibility(self.conout, visible)
     }
 
     // You can't have both ENABLE_WRAP_AT_EOL_OUTPUT and
@@ -374,16 +374,28 @@ impl ConsoleRenderer {
     }
 }
 
-fn set_cursor_visible(handle: HANDLE, visible: BOOL) -> Result<()> {
+pub struct ConsoleCursorGuard(HANDLE);
+
+impl Drop for ConsoleCursorGuard {
+    fn drop(&mut self) {
+        let _ = set_cursor_visibility(self.0, true);
+    }
+}
+
+fn set_cursor_visibility(handle: HANDLE, visible: bool) -> Result<Option<ConsoleCursorGuard>> {
     let mut info = unsafe { mem::zeroed() };
     check(unsafe { wincon::GetConsoleCursorInfo(handle, &mut info) })?;
-    if info.bVisible == visible {
-        return Ok(());
+    let b = if visible { TRUE } else { FALSE };
+    if info.bVisible == b {
+        return Ok(None);
     }
-    info.bVisible = visible;
-    Ok(check(unsafe {
-        wincon::SetConsoleCursorInfo(handle, &info)
-    })?)
+    info.bVisible = b;
+    check(unsafe { wincon::SetConsoleCursorInfo(handle, &info) })?;
+    Ok(if visible {
+        None
+    } else {
+        Some(ConsoleCursorGuard(handle))
+    })
 }
 
 impl Renderer for ConsoleRenderer {
@@ -449,11 +461,8 @@ impl Renderer for ConsoleRenderer {
             }
         }
         let info = self.get_console_screen_buffer_info()?;
-        self.set_cursor_visible(FALSE)?; // just to avoid flickering
-        let handle = self.conout;
-        scopeguard::defer! {
-            let _ = set_cursor_visible(handle, TRUE);
-        }
+        // just to avoid flickering
+        let mut guard = self.set_cursor_visibility(false)?;
         // position at the start of the prompt, clear to end of previous input
         self.clear_old_rows(&info, old_layout)?;
         // display prompt, input line and hint
@@ -465,7 +474,7 @@ impl Renderer for ConsoleRenderer {
         coord.X = cursor.col as i16;
         coord.Y -= (end_pos.row - cursor.row) as i16;
         self.set_console_cursor_position(coord, info.dwSize)?;
-
+        guard.take();
         Ok(())
     }
 
@@ -628,6 +637,7 @@ impl Console {
 }
 
 impl Term for Console {
+    type CursorGuard = ConsoleCursorGuard;
     type ExternalPrinter = ExternalPrinter;
     type KeyMap = ConsoleKeyMap;
     type Mode = ConsoleMode;
@@ -831,6 +841,14 @@ impl Term for Console {
             conout: self.conout,
         })
     }
+
+    fn set_cursor_visibility(&mut self, visible: bool) -> Result<Option<ConsoleCursorGuard>> {
+        if self.conout_isatty {
+            set_cursor_visibility(self.conout, visible)
+        } else {
+            Ok(None)
+        }
+    }
 }
 
 impl Drop for Console {