Add error on unsaved quit

src/main.rs

@@ -31,9 +31,10 @@ use crossbeam_channel::Sender;
 use crossterm::{
     cursor,
     event::{Event, KeyCode, KeyEvent},
-    terminal, Result, QueueableCommand,
+    terminal, QueueableCommand, Result,
 };
 use parking_lot::Mutex;
+use ropey::Rope;
 use yacexits::{exit, EX_DATAERR, EX_UNAVAILABLE};
 
 mod actions;
@@ -106,6 +107,7 @@ pub struct State {
     pub cursor: Cursor,
     pub file: Option<OsString>,
     pub mode: Mode,
+    pub last_saved: Rope,
     pub scroll: Cursor,
     pub size: (usize, usize),
     pub quit: bool,
@@ -116,6 +118,7 @@ impl State {
     pub fn from_str(file_name: Option<OsString>, text: &str) -> Result<Self> {
         let styles = Arc::new(Mutex::new(StyleStore::default()));
         let buffer = Buffer::from_str(styles.clone(), text);
+        let last_saved = buffer.as_ref().clone();
         let (cols, rows) = terminal::size()?;
         let theme_tx = config::ThemeWatcher::spawn(styles.clone());
 
@@ -125,6 +128,7 @@ impl State {
             cursor: Cursor::default(),
             file: file_name,
             mode: Mode::default(),
+            last_saved,
             scroll: Cursor::default(),
             size: (cols as usize, rows as usize),
             quit: false,
@@ -327,11 +331,10 @@ impl State {
     }
 
     fn write_buffer(&mut self, file: OsString) -> Result<()> {
+        self.last_saved = self.buffer.as_ref().clone();
         let out = self.buffer.as_ref().bytes().collect::<Vec<u8>>();
         let mut handle = OpenOptions::new().write(true).open(file)?;
-
         handle.write_all(out.as_slice())?;
-
         Ok(())
     }
 
@@ -360,7 +363,14 @@ impl State {
         let args = &command_parts[1..];
 
         match *command {
-            "q" => self.quit = true,
+            "q!" => self.quit = true,
+            "q" => {
+                if self.last_saved == *self.buffer.as_ref() {
+                    self.quit = true;
+                } else {
+                    return Err("Buffer is unsaved (add ! to override".into());
+                }
+            }
             "w" => return self.write_command(command, args),
             "wq" => {
                 self.write_command(command, args)?;