add dirty flag check, quit confirmation

src/document.rs

@@ -6,7 +6,8 @@ use std::io::{Error, Write};
 #[derive(Default)]
 pub struct Document {
     rows: Vec<Row>,
-    pub file_name: Option<String>
+    pub file_name: Option<String>,
+    dirty: bool
 }
 
 impl Document {
@@ -18,7 +19,8 @@ impl Document {
         }
         Ok(Self {
             rows,
-            file_name: Some(filename.to_string())
+            file_name: Some(filename.to_string()),
+            dirty: false
         })
     }
     pub fn row(&self, index: usize) -> Option<&Row> {
@@ -31,6 +33,10 @@ impl Document {
         self.rows.len()
     }
     pub fn insert(&mut self, at: &Position, c: char) {
+        if at.y > self.len() {
+            return;
+        }
+        self.dirty = true;
         if c == '\n' {
             self.insert_newline(at);
             return;
@@ -39,7 +45,7 @@ impl Document {
             let mut row = Row::default();
             row.insert(0, c);
             self.rows.push(row);
-        } else if at.y < self.len() {
+        } else {
             let row = self.rows.get_mut(at.y).unwrap();
             row.insert(at.x, c);
         }
@@ -49,6 +55,7 @@ impl Document {
         if at.y >= len {
             return;
         }
+        self.dirty = true;
 
         if at.x == self.rows.get_mut(at.y).unwrap().len() && at.y < len - 1 {
             let next_row = self.rows.remove(at.y + 1);
@@ -60,24 +67,25 @@ impl Document {
         }
     }
     fn insert_newline(&mut self, at: &Position) {
-        if at.y > self.len() {
-            return;
-        }
         if at.y == self.len() {
             self.rows.push(Row::default());
             return;
         }
         let new_row = self.rows.get_mut(at.y).unwrap().split(at.x);
         self.rows.insert(at.y + 1, new_row);
     }
-    pub fn save(&self) -> Result<(), Error> {
+    pub fn save(&mut self) -> Result<(), Error> {
         if let Some(file_name) = &self.file_name {
             let mut file = fs::File::create(file_name)?;
             for row in &self.rows {
                 file.write_all(row.as_bytes())?;
                 file.write_all(b"\n")?;
             }
+            self.dirty = false;
         }
         Ok(())
     }
+    pub fn is_dirty(&self) -> bool {
+        self.dirty
+    }
 }

src/editor.rs

@@ -2,6 +2,7 @@ use crate::Document;
 use crate::Row;
 use crate::Terminal;
 use std::env;
+use std::u8;
 use std::usize;
 use termion::event::Key;
 use termion::color;
@@ -11,6 +12,7 @@ use std::time::Instant;
 const STATUS_FG_COLOR: color::Rgb = color::Rgb(63, 63, 63);
 const STATUS_BG_COLOR: color::Rgb = color::Rgb(239, 239, 239);
 const VERSION: &str = env!("CARGO_PKG_VERSION");
+const QUIT_TIMES: u8 = 3;
 
 #[derive(Default)]
 pub struct Position {
@@ -38,7 +40,8 @@ pub struct Editor {
     cursor_position: Position,
     document: Document,
     offset: Position,
-    status_message: StatusMessage
+    status_message: StatusMessage,
+    quit_times: u8
 }
 
 impl Editor {
@@ -77,7 +80,8 @@ impl Editor {
             document,
             cursor_position: Position::default(),
             offset: Position::default(),
-            status_message: StatusMessage::from(initial_status)
+            status_message: StatusMessage::from(initial_status),
+            quit_times: QUIT_TIMES
         }
     }
 
@@ -102,8 +106,18 @@ impl Editor {
     fn process_keypress(&mut self) -> Result<(), std::io::Error> {
         let pressed_key = Terminal::read_key()?;
         match pressed_key {
-            Key::Ctrl('q') => self.should_quit = true,
             Key::Ctrl('s') => self.save(),
+            Key::Ctrl('q') => {
+                if self.quit_times > 0 && self.document.is_dirty() {
+                    self.status_message = StatusMessage::from(format!(
+                        "Warning! File has unsaved changes. Press Ctrl-Q {} more times to quit",
+                        self.quit_times
+                    ));
+                    self.quit_times -= 1;
+                    return Ok(());
+                }
+                self.should_quit = true
+            }
             Key::Char(c) => {
                 self.document.insert(&self.cursor_position, c);
                 self.move_cursor(Key::Right);
@@ -126,6 +140,10 @@ impl Editor {
             _ => ()
         }
         self.scroll();
+        if self.quit_times < QUIT_TIMES {
+            self.quit_times = QUIT_TIMES;
+            self.status_message = StatusMessage::from(String::new());
+        }
         Ok(())
     }
     pub fn draw_row(&self, row: &Row) {
@@ -246,12 +264,23 @@ impl Editor {
     fn draw_status_bar(&self) {
         let mut status;
         let width = self.terminal.size().width as usize;
+        let modified_indicator = if self.document.is_dirty() {
+            " (modified)"
+        } else {
+            ""
+        };
+
         let mut file_name = "[No Name]".to_string();
         if let Some(name) = &self.document.file_name {
             file_name = name.clone();
             file_name.truncate(20);
         }
-        status = format!("{} - {} lines", file_name, self.document.len());
+        status = format!(
+            "{} - {} lines{}", 
+            file_name, 
+            self.document.len(),
+            modified_indicator
+        );
         status.truncate(width);
         let line_indicator = format!(
             "{}/{}",