feat: implement rudimentary save functionality

src/document.rs

@@ -1,6 +1,7 @@
 use crate::Position;
 use crate::Row;
 use std::fs;
+use std::io::{Error, Write};
 
 #[derive(Default)]
 pub struct Document {
@@ -74,4 +75,15 @@ impl Document {
             file_name: Some(filename.to_string()),
         })
     }
+
+    pub fn save(&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")?;
+            }
+        }
+        Ok(())
+    }
 }

src/editor.rs

@@ -42,7 +42,7 @@ impl StatusMessage {
 impl Default for Editor {
     fn default() -> Self {
         let args: Vec<String> = env::args().collect();
-        let mut initial_status = String::from("HELP: Ctrl-Q = quit");
+        let mut initial_status = String::from("HELP: Ctrl-Q = quit, Ctrl-S = save");
         let document = if args.len() > 1 {
             let file_name = &args[1];
             let doc = Document::open(file_name);
@@ -85,6 +85,14 @@ impl Editor {
         let pressed_key = Terminal::read_key()?;
         match pressed_key {
             Key::Ctrl('q') => self.should_quit = true,
+            Key::Ctrl('s') => {
+                if self.document.save().is_ok() {
+                    self.status_message =
+                        StatusMessage::from("File saved successfully.".to_string());
+                } else {
+                    self.status_message = StatusMessage::from("Error writing file!".to_string());
+                }
+            }
             Key::Char(c) => {
                 self.document.insert(&self.cursor_position, c);
                 self.move_cursor(Key::Right);

src/row.rs

@@ -86,4 +86,8 @@ impl Row {
         self.update_len();
         Self::from(&remainder[..])
     }
+
+    pub fn as_bytes(&self) -> &[u8] {
+        self.contents.as_bytes()
+    }
 }