refactor: extract terminal setup/teardown

src/main.rs

@@ -6,7 +6,7 @@ mod persistence;
 mod ui;
 mod view;
 
-use std::io;
+use std::io::{self, Stdout};
 use std::path::PathBuf;
 use std::time::Duration;
 
@@ -202,7 +202,7 @@ fn parse_args(args: Vec<String>) -> Box<dyn Runnable> {
 }
 
 fn get_initial_model(file_path: &Option<PathBuf>) -> Result<Model> {
-    return if let Some(ref path) = file_path {
+    if let Some(ref path) = file_path {
         if path.exists() {
             let mut m = persistence::load(path)
                 .with_context(|| format!("Failed to load {}", path.display()))?;
@@ -218,7 +218,29 @@ fn get_initial_model(file_path: &Option<PathBuf>) -> Result<Model> {
         }
     } else {
         Ok(Model::new("New Model"))
-    };
+    }
+}
+
+struct TuiGuard<'a> {
+    terminal: Terminal<CrosstermBackend<&'a mut Stdout>>,
+}
+
+impl<'a> TuiGuard<'a> {
+    fn enter(out: &'a mut Stdout) -> Result<Self> {
+        enable_raw_mode()?;
+        execute!(out, EnterAlternateScreen)?;
+        let backend = CrosstermBackend::new(out);
+        let terminal = Terminal::new(backend)?;
+
+        Ok(Self { terminal })
+    }
+}
+
+impl<'a> Drop for TuiGuard<'a> {
+    fn drop(&mut self) {
+        let _ = execute!(self.terminal.backend_mut(), LeaveAlternateScreen);
+        let _ = disable_raw_mode();
+    }
 }
 
 fn run_tui(
@@ -226,11 +248,8 @@ fn run_tui(
     file_path: Option<PathBuf>,
     import_json: Option<serde_json::Value>,
 ) -> Result<()> {
-    enable_raw_mode()?;
     let mut stdout = io::stdout();
-    execute!(stdout, EnterAlternateScreen)?;
+    let mut tui_context = TuiGuard::enter(&mut stdout)?;
-    let backend = CrosstermBackend::new(stdout);
-    let mut terminal = Terminal::new(backend)?;
 
     let mut app = App::new(model, file_path);
     if let Some(json) = import_json {
@@ -238,7 +257,7 @@ fn run_tui(
     }
 
     loop {
-        terminal.draw(|f| draw(f, &app))?;
+        tui_context.terminal.draw(|f| draw(f, &app))?;
 
         if event::poll(Duration::from_millis(100))? {
             if let Event::Key(key) = event::read()? {
@@ -253,8 +272,6 @@ fn run_tui(
         }
     }
 
-    disable_raw_mode()?;
-    execute!(terminal.backend_mut(), LeaveAlternateScreen)?;
     Ok(())
 }