Add ClearOffset to replicate macOS Cmd+K behavior

zellij-client/src/input_handler.rs

@@ -302,6 +302,7 @@ impl InputHandler {
             },
             Action::CloseFocus
             | Action::ClearScreen
+            | Action::ClearScrollback(_)
             | Action::NewPane(..)
             | Action::Run(_)
             | Action::NewTiledPane(..)

zellij-server/src/panes/grid.rs

@@ -1115,6 +1115,32 @@ impl Grid {
         self.reset_terminal_state();
         self.mark_for_rerender();
     }
+    /// Clears the scrollback and positions the current active line on top of the pane.
+    pub fn clear_scrollback(&mut self, offset: i32) {
+        if self.alternate_screen_state.is_some() {
+            log::warn!("Tried to clear scrollback of pane with alternate_screen_state");
+            return;
+        }
+
+        let new_viewport = self
+            .viewport
+            .clone()
+            .into_iter()
+            .skip(self.viewport.len().saturating_sub(offset as usize + 1))
+            .collect::<Vec<_>>();
+
+        self.clear_viewport_before_rendering = true;
+        self.lines_above = VecDeque::new();
+        self.lines_below = vec![];
+        self.viewport = vec![Row::new().canonical()];
+        self.scroll_region = None;
+        self.scrollback_buffer_lines = 0;
+        self.viewport = new_viewport;
+        self.cursor.y = offset as usize;
+        self.output_buffer.update_all_lines();
+
+        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);

zellij-server/src/panes/plugin_pane.rs

@@ -490,6 +490,9 @@ impl Pane for PluginPane {
     fn clear_scroll(&mut self) {
         // noop
     }
+    fn clear_scrollback(&mut self, _offset: i32) {
+        // noop
+    }
     fn start_selection(&mut self, start: &Position, client_id: ClientId) {
         self.send_plugin_instructions
             .send(PluginInstruction::Update(vec![(

zellij-server/src/panes/terminal_pane.rs

@@ -503,6 +503,9 @@ impl Pane for TerminalPane {
     fn clear_screen(&mut self) {
         self.grid.clear_screen()
     }
+    fn clear_scrollback(&mut self, offset: i32) {
+        self.grid.clear_scrollback(offset)
+    }
     fn scroll_up(&mut self, count: usize, _client_id: ClientId) {
         self.grid.move_viewport_up(count);
         self.set_should_render(true);

zellij-server/src/plugins/zellij_exports.rs

@@ -822,6 +822,18 @@ fn clear_screen(env: &ForeignFunctionEnv) {
     let action = Action::ClearScreen;
     apply_action!(action, error_msg, env);
 }
+
+fn clear_scrollback(env: &ForeignFunctionEnv, offset: i32) {
+    let error_msg = || {
+        format!(
+            "failed to clear scrollback in plugin {}",
+            env.plugin_env.name()
+        )
+    };
+    let action = Action::ClearScrollback(offset);
+    apply_action!(action, error_msg, env);
+}
+
 fn scroll_up(env: &ForeignFunctionEnv) {
     let error_msg = || format!("failed to scroll up in plugin {}", env.plugin_env.name());
     let action = Action::ScrollUp;

zellij-server/src/route.rs

@@ -168,6 +168,11 @@ pub(crate) fn route_action(
                 .send_to_screen(ScreenInstruction::ClearScreen(client_id))
                 .with_context(err_context)?;
         },
+        Action::ClearScrollback(offset) => {
+            senders
+                .send_to_screen(ScreenInstruction::ClearScrollback(client_id, offset))
+                .with_context(err_context)?;
+        },
         Action::DumpScreen(val, full) => {
             senders
                 .send_to_screen(ScreenInstruction::DumpScreen(val, client_id, full))

zellij-server/src/screen.rs

@@ -167,6 +167,7 @@ pub enum ScreenInstruction {
     MovePaneLeft(ClientId),
     Exit,
     ClearScreen(ClientId),
+    ClearScrollback(ClientId, i32),
     DumpScreen(String, ClientId, bool),
     EditScrollback(ClientId),
     ScrollUp(ClientId),
@@ -366,6 +367,7 @@ impl From<&ScreenInstruction> for ScreenContext {
             ScreenInstruction::MovePaneLeft(..) => ScreenContext::MovePaneLeft,
             ScreenInstruction::Exit => ScreenContext::Exit,
             ScreenInstruction::ClearScreen(..) => ScreenContext::ClearScreen,
+            ScreenInstruction::ClearScrollback(..) => ScreenContext::ClearScrollback,
             ScreenInstruction::DumpScreen(..) => ScreenContext::DumpScreen,
             ScreenInstruction::EditScrollback(..) => ScreenContext::EditScrollback,
             ScreenInstruction::ScrollUp(..) => ScreenContext::ScrollUp,
@@ -2247,6 +2249,19 @@ pub(crate) fn screen_thread_main(
                 screen.render()?;
                 screen.unblock_input()?;
             },
+            ScreenInstruction::ClearScrollback(client_id, offset) => {
+                active_tab_and_connected_client_id!(
+                    screen,
+                    client_id,
+                    |tab: &mut Tab, client_id: ClientId| tab.clear_scrollback_active_terminal_screen(
+                        client_id,
+                        offset,
+                    ),
+                    ?
+                );
+                screen.render()?;
+                screen.unblock_input()?;
+            },
             ScreenInstruction::DumpScreen(file, client_id, full) => {
                 active_tab_and_connected_client_id!(
                     screen,

zellij-server/src/tab/mod.rs

@@ -250,6 +250,7 @@ pub trait Pane {
     fn pull_left(&mut self, count: usize);
     fn pull_up(&mut self, count: usize);
     fn clear_screen(&mut self);
+    fn clear_scrollback(&mut self, offset: i32);
     fn dump_screen(&mut self, _client_id: ClientId, _full: bool) -> String {
         "".to_owned()
     }
@@ -2503,6 +2504,16 @@ impl Tab {
         }
         Ok(())
     }
+    pub fn clear_scrollback_active_terminal_screen(
+        &mut self,
+        client_id: ClientId,
+        offset: i32,
+    ) -> Result<()> {
+        if let Some(active_pane) = self.get_active_pane_or_floating_pane_mut(client_id) {
+            active_pane.clear_scrollback(offset);
+        }
+        Ok(())
+    }
     pub fn dump_active_terminal_screen(
         &mut self,
         file: Option<String>,

zellij-utils/assets/prost/api.action.rs

@@ -100,6 +100,8 @@ pub mod action {
         RenamePluginPanePayload(super::IdAndName),
         #[prost(message, tag = "44")]
         RenameTabPayload(super::IdAndName),
+        #[prost(message, tag = "45")]
+        ClearScrollbackPayload(i32),
     }
 }
 #[allow(clippy::derive_partial_eq_without_eq)]
@@ -400,6 +402,7 @@ pub enum ActionName {
     BreakPane = 77,
     BreakPaneRight = 78,
     BreakPaneLeft = 79,
+    ClearScrollback = 80,
 }
 impl ActionName {
     /// String value of the enum field names used in the ProtoBuf definition.
@@ -422,6 +425,7 @@ impl ActionName {
             ActionName::MovePane => "MovePane",
             ActionName::MovePaneBackwards => "MovePaneBackwards",
             ActionName::ClearScreen => "ClearScreen",
+            ActionName::ClearScrollback => "ClearScrollback",
             ActionName::DumpScreen => "DumpScreen",
             ActionName::EditScrollback => "EditScrollback",
             ActionName::ScrollUp => "ScrollUp",
@@ -507,6 +511,7 @@ impl ActionName {
             "MovePane" => Some(Self::MovePane),
             "MovePaneBackwards" => Some(Self::MovePaneBackwards),
             "ClearScreen" => Some(Self::ClearScreen),
+            "ClearScrollback" => Some(Self::ClearScrollback),
             "DumpScreen" => Some(Self::DumpScreen),
             "EditScrollback" => Some(Self::EditScrollback),
             "ScrollUp" => Some(Self::ScrollUp),

zellij-utils/src/cli.rs

@@ -263,6 +263,12 @@ pub enum CliAction {
     MovePaneBackwards,
     /// Clear all buffers for a focused pane
     Clear,
+    /// Clear the scrollback and positions the current active line on top of the pane.
+    ClearScrollback {
+        /// Offset of lines from the current viewport to keep
+        #[clap(short, long, value_parser, default_value("1"))]
+        offset: i8,
+    },
     /// Dump the focused pane to a file
     DumpScreen {
         path: PathBuf,

zellij-utils/src/errors.rs

@@ -256,6 +256,7 @@ pub enum ScreenContext {
     MovePaneLeft,
     Exit,
     ClearScreen,
+    ClearScrollback,
     DumpScreen,
     EditScrollback,
     ScrollUp,

zellij-utils/src/input/actions.rs

@@ -122,6 +122,8 @@ pub enum Action {
     MovePaneBackwards,
     /// Clear all buffers of a current screen
     ClearScreen,
+    /// Clear the scrollback and positions the current active line on top of the pane.
+    ClearScrollback(i32),
     /// Dumps the screen to a file
     DumpScreen(String, bool),
     /// Scroll up in focus pane.
@@ -276,6 +278,9 @@ impl Action {
             CliAction::MovePane { direction } => Ok(vec![Action::MovePane(direction)]),
             CliAction::MovePaneBackwards => Ok(vec![Action::MovePaneBackwards]),
             CliAction::Clear => Ok(vec![Action::ClearScreen]),
+            CliAction::ClearScrollback { offset } => {
+                Ok(vec![Action::ClearScrollback(offset as i32)])
+            },
             CliAction::DumpScreen { path, full } => Ok(vec![Action::DumpScreen(
                 path.as_os_str().to_string_lossy().into(),
                 full,

zellij-utils/src/kdl/mod.rs

@@ -385,6 +385,16 @@ impl Action {
                 })? as u32;
                 Ok(Action::GoToTab(tab_index))
             },
+            "ClearScrollback" => {
+                let offset = *bytes.get(0).ok_or_else(|| {
+                    ConfigError::new_kdl_error(
+                        format!("Missing scrollback offset"),
+                        action_node.span().offset(),
+                        action_node.span().len(),
+                    )
+                })? as u32;
+                Ok(Action::ClearScrollback(offset as i32))
+            },
             _ => Err(ConfigError::new_kdl_error(
                 "Failed to parse action".into(),
                 action_node.span().offset(),
@@ -703,6 +713,9 @@ 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),
+            "ClearScrollback" => {
+                parse_kdl_action_u8_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),

zellij-utils/src/plugin_api/action.rs

@@ -732,6 +732,10 @@ impl TryFrom<Action> for ProtobufAction {
                 name: ProtobufActionName::ClearScreen as i32,
                 optional_payload: None,
             }),
+            Action::ClearScrollback(offset) => Ok(ProtobufAction {
+                name: ProtobufActionName::ClearScrollback as i32,
+                optional_payload: Some(OptionalPayload::ClearScrollbackPayload(offset)),
+            }),
             Action::DumpScreen(file_path, include_scrollback) => Ok(ProtobufAction {
                 name: ProtobufActionName::DumpScreen as i32,
                 optional_payload: Some(OptionalPayload::DumpScreenPayload(DumpScreenPayload {