Fix broken SIGWINCH detection / window resizing caused by clashing si…

…gnal handler registered by rustyline.

CHANGELOG.md

@@ -18,6 +18,8 @@ Bug Fixes:
   status bar to be highlighted and copied.
 - [Issue #61]: Display error message for unrecognized CSI escape
   sequences and other IO errors instead of panicking.
+- [Issue #62]: Fix broken window resizing / SIGWINCH detection caused
+  by clashing signal handler registered by rustyline.
 
 
 v0.7.2 (2022-02-20)

src/input.rs

@@ -13,7 +13,7 @@ const BUFFER_SIZE: usize = 1024;
 
 const ESCAPE: u8 = 0o33;
 
-pub fn get_input() -> impl Iterator<Item = io::Result<TuiEvent>> {
+pub fn remap_dev_tty_to_stdin() {
     // The readline library we use, rustyline, always gets its input from STDIN.
     // If jless accepts its input from STDIN, then rustyline can't accept input.
     // To fix this, we open up /dev/tty, and remap it to STDIN, as suggested in
@@ -30,8 +30,14 @@ pub fn get_input() -> impl Iterator<Item = io::Result<TuiEvent>> {
         let path = std::ffi::CString::new("r").unwrap();
         let _ = libc::freopen(filename.as_ptr(), path.as_ptr(), libc_stdhandle::stdin());
     }
+}
 
+pub fn get_input() -> impl Iterator<Item = io::Result<TuiEvent>> {
     let (sigwinch_read, sigwinch_write) = UnixStream::pair().unwrap();
+    // NOTE: This overrides the SIGWINCH handler registered by rustyline.
+    // We should maybe get a reference to the existing signal handler
+    // and call it when appropriate, but it seems to only be used to handle
+    // line wrapping, and it seems to work fine without it.
     pipe::register(SIGWINCH, sigwinch_write).unwrap();
     TuiInput::new(stdin(), sigwinch_read)
 }

src/main.rs

@@ -53,12 +53,12 @@ fn main() {
         std::process::exit(0);
     }
 
-    // Create our input *before* constructing the App. When we get the input,
-    // we use freopen to remap /dev/tty to STDIN so that rustyline works when
+    // We use freopen to remap /dev/tty to STDIN so that rustyline works when
     // JSON input is provided via STDIN. rustyline gets initialized when we
-    // create the App, so by putting this before, we make sure rustyline gets
-    // the /dev/tty input.
-    let input = Box::new(input::get_input());
+    // create the App, so by putting this before creating the app, we make
+    // sure rustyline gets the /dev/tty input.
+    input::remap_dev_tty_to_stdin();
+
     let stdout = MouseTerminal::from(HideCursor::from(AlternateScreen::from(
         io::stdout().into_raw_mode().unwrap(),
     )));
@@ -77,7 +77,7 @@ fn main() {
         }
     };
 
-    app.run(input);
+    app.run(Box::new(input::get_input()));
 }
 
 fn print_pretty_printed_input(input: String, data_format: DataFormat) {