Asynchronous processing of keyboard events…

…to pave the way for async handling of initial traversal and events, that is, processing both at the same time.
Byron · Mar 29, 2020 · 7f32fb9 · 7f32fb9
1 parent 9824585
commit 7f32fb9
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Showing 3 changed files with 67 additions and 43 deletions.
diff --git a/Cargo.lock b/Cargo.lock
diff --git a/Cargo.toml b/Cargo.toml
@@ -26,6 +26,7 @@ tui-react = { path = "./tui-react", version = "0.2" }
 num_cpus = "1.10.0"
 unicode-segmentation = "1.3.0"
 filesize = "0.2.0"
+crossbeam-channel = "0.4.2"
 
 [[bin]]
 name="dua"

diff --git a/src/interactive/app/eventloop.rs b/src/interactive/app/eventloop.rs
@@ -45,6 +45,11 @@ pub struct TerminalApp {
     pub window: MainWindow,
 }
 
+/// A set of events that multiple kinds of input sources
+enum Event {
+    Key(Key),
+}
+
 impl TerminalApp {
     pub fn draw_window<B>(
         window: &mut MainWindow,
@@ -73,61 +78,78 @@ impl TerminalApp {
     pub fn process_events<B>(
         &mut self,
         mut terminal: Terminal<B>,
-        keys: impl Iterator<Item = Result<Key, io::Error>>,
+        keys: impl Iterator<Item = Result<Key, io::Error>> + Send + 'static,
     ) -> Result<WalkResult, Error>
     where
         B: Backend,
     {
         use termion::event::Key::*;
         use FocussedPane::*;
 
+        let (keys_tx, keys_rx) = crossbeam_channel::bounded(1);
+        std::thread::spawn(move || {
+            for key in keys.filter_map(Result::ok) {
+                if keys_tx.send(Event::Key(key)).is_err() {
+                    break;
+                }
+            }
+        });
+
         self.draw(&mut terminal)?;
-        for key in keys.filter_map(Result::ok) {
+        for event in keys_rx {
             self.update_message();
-            match key {
-                Char('?') => self.toggle_help_pane(),
-                Char('\t') => {
-                    self.cycle_focus();
-                }
-                Ctrl('c') => break,
-                Char('q') | Esc => match self.state.focussed {
-                    Main => {
-                        drop(terminal);
-                        io::stdout().flush().ok();
-                        // Exit 'quickly' to avoid having to wait for all memory to be freed by us.
-                        // Let the OS do it - we have nothing to lose, literally.
-                        std::process::exit(0);
-                    }
-                    Mark => self.state.focussed = Main,
-                    Help => {
-                        self.state.focussed = Main;
-                        self.window.help_pane = None
+            match event {
+                Event::Key(key) => {
+                    match key {
+                        Char('?') => self.toggle_help_pane(),
+                        Char('\t') => {
+                            self.cycle_focus();
+                        }
+                        Ctrl('c') => break,
+                        Char('q') | Esc => match self.state.focussed {
+                            Main => {
+                                drop(terminal);
+                                io::stdout().flush().ok();
+                                // Exit 'quickly' to avoid having to wait for all memory to be freed by us.
+                                // Let the OS do it - we have nothing to lose, literally.
+                                std::process::exit(0);
+                            }
+                            Mark => self.state.focussed = Main,
+                            Help => {
+                                self.state.focussed = Main;
+                                self.window.help_pane = None
+                            }
+                        },
+                        _ => {}
                     }
-                },
-                _ => {}
-            }
 
-            match self.state.focussed {
-                FocussedPane::Mark => self.dispatch_to_mark_pane(key, &mut terminal),
-                FocussedPane::Help => {
-                    self.window.help_pane.as_mut().expect("help pane").key(key);
+                    match self.state.focussed {
+                        FocussedPane::Mark => self.dispatch_to_mark_pane(key, &mut terminal),
+                        FocussedPane::Help => {
+                            self.window.help_pane.as_mut().expect("help pane").key(key);
+                        }
+                        FocussedPane::Main => match key {
+                            Char('O') => self.open_that(),
+                            Char(' ') => self.mark_entry(false),
+                            Char('d') => self.mark_entry(true),
+                            Char('u') | Char('h') | Backspace | Left => self.exit_node(),
+                            Char('o') | Char('l') | Char('\n') | Right => self.enter_node(),
+                            Ctrl('u') | PageUp => {
+                                self.change_entry_selection(CursorDirection::PageUp)
+                            }
+                            Char('k') | Up => self.change_entry_selection(CursorDirection::Up),
+                            Char('j') | Down => self.change_entry_selection(CursorDirection::Down),
+                            Ctrl('d') | PageDown => {
+                                self.change_entry_selection(CursorDirection::PageDown)
+                            }
+                            Char('s') => self.cycle_sorting(),
+                            Char('g') => self.display.byte_vis.cycle(),
+                            _ => {}
+                        },
+                    };
+                    self.draw(&mut terminal)?;
                 }
-                FocussedPane::Main => match key {
-                    Char('O') => self.open_that(),
-                    Char(' ') => self.mark_entry(false),
-                    Char('d') => self.mark_entry(true),
-                    Char('u') | Char('h') | Backspace | Left => self.exit_node(),
-                    Char('o') | Char('l') | Char('\n') | Right => self.enter_node(),
-                    Ctrl('u') | PageUp => self.change_entry_selection(CursorDirection::PageUp),
-                    Char('k') | Up => self.change_entry_selection(CursorDirection::Up),
-                    Char('j') | Down => self.change_entry_selection(CursorDirection::Down),
-                    Ctrl('d') | PageDown => self.change_entry_selection(CursorDirection::PageDown),
-                    Char('s') => self.cycle_sorting(),
-                    Char('g') => self.display.byte_vis.cycle(),
-                    _ => {}
-                },
-            };
-            self.draw(&mut terminal)?;
+            }
         }
         Ok(WalkResult {
             num_errors: self.traversal.io_errors,