Complete chapter 4

src/editor.rs

@@ -6,7 +6,7 @@ use std::fs::File;
 use std::io;
 use std::io::prelude::*;
 use std::io::BufReader;
-use std::string::ToString;
+use std::time::{Duration, Instant};
 
 use self::EditorKey::*;
 
@@ -30,7 +30,7 @@ impl EditorRow {
 
 /// Main structure for the editor
 /// `EditorConfig` struct in C version
-#[derive(Debug, Default)]
+#[derive(Debug)]
 pub struct Editor {
     cursor_x: usize,
     cursor_y: usize,
@@ -41,6 +41,8 @@ pub struct Editor {
     screen_rows: usize,
     rows: Vec<EditorRow>,
     filename: String,
+    status_message: String,
+    status_message_time: Instant,
     output_buffer: String,
 }
 
@@ -72,6 +74,25 @@ impl EditorKey<char> {
     }
 }
 
+impl Default for Editor {
+    fn default() -> Self {
+        Editor {
+            cursor_x: 0,
+            cursor_y: 0,
+            render_x: 0,
+            col_offset: 0,
+            row_offset: 0,
+            screen_cols: 0,
+            screen_rows: 0,
+            rows: vec![],
+            filename: String::new(),
+            status_message: String::new(),
+            status_message_time: Instant::now(),
+            output_buffer: String::new(),
+        }
+    }
+}
+
 impl Editor {
     // ------------------------------------------------------------------------
     // Init
@@ -79,12 +100,11 @@ impl Editor {
 
     pub fn new() -> Self {
         let mut instance = Self::default();
+
         let size = instance.get_window_size();
-        instance.rows = vec![];
-        instance.cursor_x = 0;
-        instance.cursor_y = 0;
+
         instance.screen_cols = size.cols as usize;
-        instance.screen_rows = (size.rows - 1) as usize;
+        instance.screen_rows = (size.rows - 2) as usize;
 
         instance
     }
@@ -414,7 +434,6 @@ impl Editor {
         let mut len = left_message.len();
         let mut rlen = right_message.len();
         if len > self.screen_cols {
-
             len = self.screen_cols;
             left_message.truncate(len);
         }
@@ -428,6 +447,22 @@ impl Editor {
             self.append_out(" ");
         }
         self.append_out("\x1b[m");
+        self.append_out("\r\n");
+    }
+
+    fn draw_message_bar(&mut self) {
+        self.append_out("\x1b[K");
+
+        let mut message = self.status_message.clone();
+        let message_len = message.len();
+        if message_len > self.screen_cols {
+            message.truncate(self.screen_cols);
+        }
+
+        let five_seconds = Duration::from_secs(5);
+        if message_len > 0 && self.status_message_time.elapsed() < five_seconds {
+            self.append_out(&message);
+        }
     }
 
     pub fn refresh_screen(&mut self) -> io::Result<()> {
@@ -440,11 +475,12 @@ impl Editor {
 
         self.draw_rows();
         self.draw_status_bar();
+        self.draw_message_bar();
 
         // Move cursor to state position
         let y = (self.cursor_y - self.row_offset) + 1;
         let x = (self.render_x - self.col_offset) + 1;
-        let cursor_code = format!("\x1b[{y};{x}H", y=y, x=x);
+        let cursor_code = format!("\x1b[{y};{x}H", y = y, x = x);
         self.append_out(&cursor_code);
 
         // Show cursor
@@ -455,6 +491,25 @@ impl Editor {
         handle.write_all(&self.output_buffer.as_bytes())
     }
 
+    /// Set the status bar message
+    ///
+    /// To avoid creating a macro that would just forward to
+    /// the `format!` macro, this method only accepts a pre-formatted
+    /// string.
+    ///
+    /// # Example
+    ///
+    /// ```no-run
+    /// # use rs-kilo::editor::Editor;
+    /// # let editor = Editor::new();
+    /// let message = format!("{} is {}", key, status);
+    /// editor.set_status_message(&message);
+    /// ```
+    pub fn set_status_message(&mut self, message: &str) {
+        self.status_message = message.to_owned();
+        self.status_message_time = Instant::now();
+    }
+
     // ------------------------------------------------------------------------
     // Row Operations
     // ------------------------------------------------------------------------

src/main.rs

@@ -25,6 +25,8 @@ fn main() -> Result<(), Error> {
         editor.open(&args[1])?;
     }
 
+    editor.set_status_message("HELP: Ctrl-Q = quit");
+
     // Main input loop. Editor::process_keypress uses an Option Enum as a sentinel.
     // `None` is returned on a quit action, in other cases, `Some(())` is returned,
     // continuing the loop