Dirty checking

src/document.rs

@@ -7,6 +7,7 @@ use std::io::{Error, Write};
 pub struct Document {
     rows: Vec<Row>,
     pub file_name: Option<String>,
+    dirty: bool,
 }
 
 impl Document {
@@ -22,6 +23,7 @@ impl Document {
         Ok(Self {
             rows,
             file_name: Some(filename.to_string()),
+            dirty: false,
         })
     }
 
@@ -38,6 +40,13 @@ impl Document {
     }
 
     pub fn insert(&mut self, at: &Position, c: char) {
+        if at.y > self.len() {
+            return;
+        }
+
+        // File has been modified
+        self.dirty = true;
+
         if c == '\n' {
             self.insert_newline(at);
             return;
@@ -47,7 +56,7 @@ 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);
         }
@@ -59,6 +68,9 @@ impl Document {
             return
         }
 
+        // File has been modified
+        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);
             let row = self.rows.get_mut(at.y).unwrap();
@@ -69,7 +81,7 @@ impl Document {
         }
     }
 
-    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)?;
 
@@ -77,16 +89,19 @@ impl Document {
                 file.write_all(row.as_bytes())?;
                 file.write_all(b"\n")?;
             }
+
+            // File has been cleaned! (Saved)
+            self.dirty = false;
         }
 
         Ok(())
     }
 
-    fn insert_newline(&mut self, at: &Position) {
-        if at.y > self.len() {
-            return;
-        }
+    pub fn is_dirty(&self) -> bool {
+        self.dirty
+    }
 
+    fn insert_newline(&mut self, at: &Position) {
         if at.y == self.len() {
             self.rows.push(Row::default());
             return;

src/editor.rs

@@ -107,6 +107,11 @@ 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 {
@@ -114,7 +119,12 @@ impl Editor {
             file_name.truncate(20);
         }
 
-        status = format!("{} - {} lines", file_name, self.document.len());
+        status = format!(
+            "{} - {} lines{}",
+            file_name,
+            self.document.len(),
+            modified_indicator
+        );
 
         let line_indicator = format!(
             "{}/{}",