feat(terminal): cli and bindable action to clear all buffers for a specific pane (#2239)

* fix typo

* Add clear screen action

* add proper test

* added bindable action; remove pointless default impl

* add default binding

* use imsnif's variant

* remove commented example config

* remove log line

---------

Co-authored-by: Aram Drevekenin <aram@poor.dev>

14 files changed, 83 insertions, 2 deletions

diff --git a/docs/MANPAGE.md b/docs/MANPAGE.md
index cd662ef4..ad06d7ba 100644
--- a/docs/MANPAGE.md
+++ b/docs/MANPAGE.md
@@ -153,6 +153,7 @@ ACTIONS
   next ID.
 * __MoveFocus: <Direction\>__ -  moves focus in the specified direction (Left,
   Right, Up, Down).
+* __Clear__ - clears current screen.
 * __DumpScreen: <File\>__ - dumps the screen in the specified file.
 * __EditScrollback__ - replaces the current pane with the scrollback buffer.
 * __ScrollUp__ - scrolls up 1 line in the focused pane.
diff --git a/src/sessions.rs b/src/sessions.rs
index 0ddcfcb2..5f3354de 100644
--- a/src/sessions.rs
+++ b/src/sessions.rs
@@ -207,7 +207,7 @@ pub(crate) fn assert_session_ne(name: &str) {
         process::exit(1);
     }
     if name.contains('/') {
-        eprintln!("Session name cannot contains '/'.");
+        eprintln!("Session name cannot contain '/'.");
         process::exit(1);
     }
 
diff --git a/zellij-client/src/input_handler.rs b/zellij-client/src/input_handler.rs
index e764786c..3efe6a72 100644
--- a/zellij-client/src/input_handler.rs
+++ b/zellij-client/src/input_handler.rs
@@ -298,6 +298,7 @@ impl InputHandler {
                     .send_to_server(ClientToServerMsg::Action(action, None));
             },
             Action::CloseFocus
+            | Action::ClearScreen
             | Action::NewPane(..)
             | Action::Run(_)
             | Action::ToggleFloatingPanes
diff --git a/zellij-server/src/panes/grid.rs b/zellij-server/src/panes/grid.rs
index 16ed8aa6..b76d21ec 100644
--- a/zellij-server/src/panes/grid.rs
+++ b/zellij-server/src/panes/grid.rs
@@ -1109,7 +1109,16 @@ impl Grid {
             Some((self.cursor.x, self.cursor.y))
         }
     }
-
+    /// Clears all buffers with text for a current screen
+    pub fn clear_screen(&mut self) {
+        if self.alternate_screen_state.is_some() {
+            log::warn!("Tried to clear pane with alternate_screen_state");
+            return;
+        }
+        self.reset_terminal_state();
+        self.mark_for_rerender();
+    }
+    /// Dumps all lines above terminal vieport and the viewport itself to a string
     pub fn dump_screen(&mut self, full: bool) -> String {
         let viewport: String = dump_screen!(self.viewport);
         if !full {
diff --git a/zellij-server/src/panes/plugin_pane.rs b/zellij-server/src/panes/plugin_pane.rs
index 28828907..980438c5 100644
--- a/zellij-server/src/panes/plugin_pane.rs
+++ b/zellij-server/src/panes/plugin_pane.rs
@@ -433,6 +433,9 @@ impl Pane for PluginPane {
             )]))
             .unwrap();
     }
+    fn clear_screen(&mut self) {
+        // do nothing
+    }
     fn clear_scroll(&mut self) {
         // noop
     }
diff --git a/zellij-server/src/panes/terminal_pane.rs b/zellij-server/src/panes/terminal_pane.rs
index d48df67a..469cfa09 100644
--- a/zellij-server/src/panes/terminal_pane.rs
+++ b/zellij-server/src/panes/terminal_pane.rs
@@ -499,6 +499,9 @@ impl Pane for TerminalPane {
     fn dump_screen(&mut self, _client_id: ClientId, full: bool) -> String {
         self.grid.dump_screen(full)
     }
+    fn clear_screen(&mut self) {
+        self.grid.clear_screen()
+    }
     fn scroll_up(&mut self, count: usize, _client_id: ClientId) {
         self.grid.move_viewport_up(count);
         self.set_should_render(true);
diff --git a/zellij-server/src/route.rs b/zellij-server/src/route.rs
index f63da2d2..c240ec40 100644
--- a/zellij-server/src/route.rs
+++ b/zellij-server/src/route.rs
@@ -172,6 +172,12 @@ pub(crate) fn route_action(
                 .send_to_screen(ScreenInstruction::MovePaneBackwards(client_id))
                 .with_context(err_context)?;
         },
+        Action::ClearScreen => {
+            session
+                .senders
+                .send_to_screen(ScreenInstruction::ClearScreen(client_id))
+                .with_context(err_context)?;
+        },
         Action::DumpScreen(val, full) => {
             session
                 .senders
diff --git a/zellij-server/src/screen.rs b/zellij-server/src/screen.rs
index f1dd3874..10f9f345 100644
--- a/zellij-server/src/screen.rs
+++ b/zellij-server/src/screen.rs
@@ -161,6 +161,7 @@ pub enum ScreenInstruction {
     MovePaneRight(ClientId),
     MovePaneLeft(ClientId),
     Exit,
+    ClearScreen(ClientId),
     DumpScreen(String, ClientId, bool),
     EditScrollback(ClientId),
     ScrollUp(ClientId),
@@ -327,6 +328,7 @@ impl From<&ScreenInstruction> for ScreenContext {
             ScreenInstruction::MovePaneRight(..) => ScreenContext::MovePaneRight,
             ScreenInstruction::MovePaneLeft(..) => ScreenContext::MovePaneLeft,
             ScreenInstruction::Exit => ScreenContext::Exit,
+            ScreenInstruction::ClearScreen(..) => ScreenContext::ClearScreen,
             ScreenInstruction::DumpScreen(..) => ScreenContext::DumpScreen,
             ScreenInstruction::EditScrollback(..) => ScreenContext::EditScrollback,
             ScreenInstruction::ScrollUp(..) => ScreenContext::ScrollUp,
@@ -1764,6 +1766,18 @@ pub(crate) fn screen_thread_main(
                 screen.render()?;
                 screen.unblock_input()?;
             },
+            ScreenInstruction::ClearScreen(client_id) => {
+                active_tab_and_connected_client_id!(
+                    screen,
+                    client_id,
+                    |tab: &mut Tab, client_id: ClientId| tab.clear_active_terminal_screen(
+                        client_id,
+                    ),
+                    ?
+                );
+                screen.render()?;
+                screen.unblock_input()?;
+            },
             ScreenInstruction::DumpScreen(file, client_id, full) => {
                 active_tab_and_connected_client_id!(
                     screen,
diff --git a/zellij-server/src/tab/mod.rs b/zellij-server/src/tab/mod.rs
index 1c1a77ac..eab71da9 100644
--- a/zellij-server/src/tab/mod.rs
+++ b/zellij-server/src/tab/mod.rs
@@ -235,6 +235,7 @@ pub trait Pane {
     fn push_right(&mut self, count: usize);
     fn pull_left(&mut self, count: usize);
     fn pull_up(&mut self, count: usize);
+    fn clear_screen(&mut self);
     fn dump_screen(&mut self, _client_id: ClientId, _full: bool) -> String {
         "".to_owned()
     }
@@ -2419,6 +2420,12 @@ impl Tab {
         }
         Ok(())
     }
+    pub fn clear_active_terminal_screen(&mut self, client_id: ClientId) -> Result<()> {
+        if let Some(active_pane) = self.get_active_pane_or_floating_pane_mut(client_id) {
+            active_pane.clear_screen();
+        }
+        Ok(())
+    }
     pub fn dump_active_terminal_screen(
         &mut self,
         file: Option<String>,
diff --git a/zellij-server/src/tab/unit/tab_integration_tests.rs b/zellij-server/src/tab/unit/tab_integration_tests.rs
index 8ccce263..13ab6710 100644
--- a/zellij-server/src/tab/unit/tab_integration_tests.rs
+++ b/zellij-server/src/tab/unit/tab_integration_tests.rs
@@ -709,6 +709,35 @@ fn dump_screen() {
 }
 
 #[test]
+fn clear_screen() {
+    let size = Size {
+        cols: 121,
+        rows: 20,
+    };
+    let client_id = 1;
+    let mut tab = create_new_tab(size, ModeInfo::default());
+    let map = Arc::new(Mutex::new(HashMap::new()));
+    tab.os_api = Box::new(FakeInputOutput {
+        file_dumps: map.clone(),
+        ..Default::default()
+    });
+    let new_pane_id = PaneId::Terminal(2);
+    tab.new_pane(new_pane_id, None, None, Some(client_id))
+        .unwrap();
+    tab.handle_pty_bytes(2, Vec::from("scratch".as_bytes()))
+        .unwrap();
+    let file = "/tmp/log-clear-screen.sh";
+    tab.clear_active_terminal_screen(client_id).unwrap();
+    tab.dump_active_terminal_screen(Some(file.to_string()), client_id, false)
+        .unwrap();
+    assert_eq!(
+        map.lock().unwrap().get(file).unwrap(),
+        "",
+        "screen was cleared properly"
+    );
+}
+
+#[test]
 fn new_floating_pane() {
     let size = Size {
         cols: 121,
diff --git a/zellij-utils/src/cli.rs b/zellij-utils/src/cli.rs
index f232438b..aa8a27ea 100644
--- a/zellij-utils/src/cli.rs
+++ b/zellij-utils/src/cli.rs
@@ -212,6 +212,8 @@ pub enum CliAction {
     },
     /// Rotate the location of the previous pane backwards
     MovePaneBackwards,
+    /// Clear all buffers for a focused pane
+    Clear,
     /// Dump the focused pane to a file
     DumpScreen {
         path: PathBuf,
diff --git a/zellij-utils/src/errors.rs b/zellij-utils/src/errors.rs
index 8a0f6331..e23c22bb 100644
--- a/zellij-utils/src/errors.rs
+++ b/zellij-utils/src/errors.rs
@@ -255,6 +255,7 @@ pub enum ScreenContext {
     MovePaneRight,
     MovePaneLeft,
     Exit,
+    ClearScreen,
     DumpScreen,
     EditScrollback,
     ScrollUp,
diff --git a/zellij-utils/src/input/actions.rs b/zellij-utils/src/input/actions.rs
index 8e614d6d..d7589791 100644
--- a/zellij-utils/src/input/actions.rs
+++ b/zellij-utils/src/input/actions.rs
@@ -120,6 +120,8 @@ pub enum Action {
     MoveFocusOrTab(Direction),
     MovePane(Option<Direction>),
     MovePaneBackwards,
+    /// Clear all buffers of a current screen
+    ClearScreen,
     /// Dumps the screen to a file
     DumpScreen(String, bool),
     /// Scroll up in focus pane.
@@ -255,6 +257,7 @@ impl Action {
             CliAction::MoveFocusOrTab { direction } => Ok(vec![Action::MoveFocusOrTab(direction)]),
             CliAction::MovePane { direction } => Ok(vec![Action::MovePane(direction)]),
             CliAction::MovePaneBackwards => Ok(vec![Action::MovePaneBackwards]),
+            CliAction::Clear => Ok(vec![Action::ClearScreen]),
             CliAction::DumpScreen { path, full } => Ok(vec![Action::DumpScreen(
                 path.as_os_str().to_string_lossy().into(),
                 full,
diff --git a/zellij-utils/src/kdl/mod.rs b/zellij-utils/src/kdl/mod.rs
index 64fe0bac..1bd1356c 100644
--- a/zellij-utils/src/kdl/mod.rs
+++ b/zellij-utils/src/kdl/mod.rs
@@ -68,6 +68,7 @@ macro_rules! parse_kdl_action_arguments {
                 "ToggleMouseMode" => Ok(Action::ToggleMouseMode),
                 "PreviousSwapLayout" => Ok(Action::PreviousSwapLayout),
                 "NextSwapLayout" => Ok(Action::NextSwapLayout),
+                "Clear" => Ok(Action::ClearScreen),
                 _ => Err(ConfigError::new_kdl_error(
                     format!("Unsupported action: {:?}", $action_name),
                     $action_node.span().offset(),
@@ -689,6 +690,7 @@ impl TryFrom<(&KdlNode, &Options)> for Action {
             },
             "Detach" => parse_kdl_action_arguments!(action_name, action_arguments, kdl_action),
             "Copy" => parse_kdl_action_arguments!(action_name, action_arguments, kdl_action),
+            "Clear" => parse_kdl_action_arguments!(action_name, action_arguments, kdl_action),
             "Confirm" => parse_kdl_action_arguments!(action_name, action_arguments, kdl_action),
             "Deny" => parse_kdl_action_arguments!(action_name, action_arguments, kdl_action),
             "Write" => parse_kdl_action_u8_arguments!(action_name, action_arguments, kdl_action),