Add ability to detach a session

src/main.rs

@@ -58,7 +58,7 @@ fn list_sessions() {
     match fs::read_dir(&*ZELLIJ_SOCK_DIR) {
         Ok(files) => {
             let mut is_empty = true;
-            let session_name = std::env::var("ZELLIJ_SESSION_NAME").unwrap_or("".into());
+            let session_name = std::env::var("ZELLIJ_SESSION_NAME").unwrap_or_else(|_| "".into());
             files.for_each(|file| {
                 let file = file.unwrap();
                 if file.file_type().unwrap().is_socket() {

src/tests/fakes.rs

@@ -299,6 +299,7 @@ impl ServerOsApi for FakeInputOutput {
         self.send_instructions_to_client.send(msg).unwrap();
     }
     fn add_client_sender(&self) {}
+    fn remove_client_sender(&self) {}
     fn update_receiver(&mut self, _stream: LocalSocketStream) {}
     fn load_palette(&self) -> Palette {
         default_palette()

zellij-server/src/lib.rs

@@ -43,6 +43,7 @@ pub(crate) enum ServerInstruction {
     UnblockInputThread,
     ClientExit,
     Error(String),
+    DetachSession,
 }
 
 impl From<ClientToServerMsg> for ServerInstruction {
@@ -52,6 +53,7 @@ impl From<ClientToServerMsg> for ServerInstruction {
             ClientToServerMsg::NewClient(pos, opts, options) => {
                 ServerInstruction::NewClient(pos, opts, options)
             }
+            ClientToServerMsg::DetachSession => ServerInstruction::DetachSession,
             _ => unreachable!(),
         }
     }
@@ -65,6 +67,7 @@ impl From<&ServerInstruction> for ServerContext {
             ServerInstruction::UnblockInputThread => ServerContext::UnblockInputThread,
             ServerInstruction::ClientExit => ServerContext::ClientExit,
             ServerInstruction::Error(_) => ServerContext::Error,
+            ServerInstruction::DetachSession => ServerContext::DetachSession,
         }
     }
 }
@@ -94,6 +97,13 @@ impl Drop for SessionMetaData {
     }
 }
 
+#[derive(Copy, Clone, Debug, Eq, PartialEq)]
+pub(crate) enum SessionState {
+    Attached,
+    Detached,
+    Uninitialized,
+}
+
 pub fn start_server(os_input: Box<dyn ServerOsApi>, socket_path: PathBuf) {
     #[cfg(not(any(feature = "test", test)))]
     daemonize::Daemonize::new()
@@ -107,7 +117,8 @@ pub fn start_server(os_input: Box<dyn ServerOsApi>, socket_path: PathBuf) {
     let (to_server, server_receiver): SyncChannelWithContext<ServerInstruction> =
         mpsc::sync_channel(50);
     let to_server = SenderWithContext::new(SenderType::SyncSender(to_server));
-    let sessions: Arc<RwLock<Option<SessionMetaData>>> = Arc::new(RwLock::new(None));
+    let session_data: Arc<RwLock<Option<SessionMetaData>>> = Arc::new(RwLock::new(None));
+    let session_state = Arc::new(RwLock::new(SessionState::Uninitialized));
 
     #[cfg(not(any(feature = "test", test)))]
     std::panic::set_hook({
@@ -122,11 +133,11 @@ pub fn start_server(os_input: Box<dyn ServerOsApi>, socket_path: PathBuf) {
     thread::Builder::new()
         .name("server_router".to_string())
         .spawn({
-            let sessions = sessions.clone();
+            let session_data = session_data.clone();
             let os_input = os_input.clone();
             let to_server = to_server.clone();
 
-            move || route_thread_main(sessions, os_input, to_server)
+            move || route_thread_main(session_data, os_input, to_server)
         })
         .unwrap();
     #[cfg(not(any(feature = "test", test)))]
@@ -138,7 +149,7 @@ pub fn start_server(os_input: Box<dyn ServerOsApi>, socket_path: PathBuf) {
             };
 
             let os_input = os_input.clone();
-            let sessions = sessions.clone();
+            let session_data = session_data.clone();
             let to_server = to_server.clone();
             let socket_path = socket_path.clone();
             move || {
@@ -150,16 +161,16 @@ pub fn start_server(os_input: Box<dyn ServerOsApi>, socket_path: PathBuf) {
                         Ok(stream) => {
                             let mut os_input = os_input.clone();
                             os_input.update_receiver(stream);
-                            let sessions = sessions.clone();
+                            let session_data = session_data.clone();
                             let to_server = to_server.clone();
                             thread::Builder::new()
                                 .name("server_router".to_string())
                                 .spawn({
-                                    let sessions = sessions.clone();
+                                    let session_data = session_data.clone();
                                     let os_input = os_input.clone();
                                     let to_server = to_server.clone();
 
-                                    move || route_thread_main(sessions, os_input, to_server)
+                                    move || route_thread_main(session_data, os_input, to_server)
                                 })
                                 .unwrap();
                         }
@@ -176,15 +187,17 @@ pub fn start_server(os_input: Box<dyn ServerOsApi>, socket_path: PathBuf) {
         err_ctx.add_call(ContextType::IPCServer((&instruction).into()));
         match instruction {
             ServerInstruction::NewClient(client_attributes, opts, config_options) => {
-                let session_data = init_session(
+                let session = init_session(
                     os_input.clone(),
                     opts,
                     config_options,
                     to_server.clone(),
                     client_attributes,
+                    session_state.clone(),
                 );
-                *sessions.write().unwrap() = Some(session_data);
+                *session_data.write().unwrap() = Some(session);
-                sessions
+                *session_state.write().unwrap() = SessionState::Attached;
+                session_data
                     .read()
                     .unwrap()
                     .as_ref()
@@ -194,18 +207,29 @@ pub fn start_server(os_input: Box<dyn ServerOsApi>, socket_path: PathBuf) {
                     .unwrap();
             }
             ServerInstruction::UnblockInputThread => {
+                if *session_state.read().unwrap() == SessionState::Attached {
                     os_input.send_to_client(ServerToClientMsg::UnblockInputThread);
                 }
+            }
             ServerInstruction::ClientExit => {
-                *sessions.write().unwrap() = None;
+                *session_data.write().unwrap() = None;
                 os_input.send_to_client(ServerToClientMsg::Exit);
                 break;
             }
+            ServerInstruction::DetachSession => {
+                *session_state.write().unwrap() = SessionState::Detached;
+                os_input.send_to_client(ServerToClientMsg::Exit);
+                os_input.remove_client_sender();
+            }
             ServerInstruction::Render(output) => {
-                os_input.send_to_client(ServerToClientMsg::Render(output))
+                if *session_state.read().unwrap() == SessionState::Attached {
+                    os_input.send_to_client(ServerToClientMsg::Render(output));
+                }
             }
             ServerInstruction::Error(backtrace) => {
+                if *session_state.read().unwrap() == SessionState::Attached {
                     os_input.send_to_client(ServerToClientMsg::ServerError(backtrace));
+                }
                 break;
             }
         }
@@ -220,6 +244,7 @@ fn init_session(
     config_options: Box<Options>,
     to_server: SenderWithContext<ServerInstruction>,
     client_attributes: ClientAttributes,
+    session_state: Arc<RwLock<SessionState>>,
 ) -> SessionMetaData {
     let (to_screen, screen_receiver): ChannelWithContext<ScreenInstruction> = mpsc::channel();
     let to_screen = SenderWithContext::new(SenderType::Sender(to_screen));
@@ -285,7 +310,13 @@ fn init_session(
             let max_panes = opts.max_panes;
 
             move || {
-                screen_thread_main(screen_bus, max_panes, client_attributes, config_options);
+                screen_thread_main(
+                    screen_bus,
+                    max_panes,
+                    client_attributes,
+                    config_options,
+                    session_state,
+                );
             }
         })
         .unwrap();

zellij-server/src/os_input_output.rs

@@ -156,6 +156,8 @@ pub trait ServerOsApi: Send + Sync {
     fn send_to_client(&self, msg: ServerToClientMsg);
     /// Adds a sender to client
     fn add_client_sender(&self);
+    /// Removes the sender to client
+    fn remove_client_sender(&self);
     /// Update the receiver socket for the client
     fn update_receiver(&mut self, stream: LocalSocketStream);
     fn load_palette(&self) -> Palette;
@@ -219,6 +221,10 @@ impl ServerOsApi for ServerOsInputOutput {
             .get_sender();
         *self.send_instructions_to_client.lock().unwrap() = Some(sender);
     }
+    fn remove_client_sender(&self) {
+        assert!(self.send_instructions_to_client.lock().unwrap().is_some());
+        *self.send_instructions_to_client.lock().unwrap() = None;
+    }
     fn update_receiver(&mut self, stream: LocalSocketStream) {
         self.receive_instructions_from_client =
             Some(Arc::new(Mutex::new(IpcReceiverWithContext::new(stream))));

zellij-server/src/route.rs

@@ -188,16 +188,16 @@ fn route_action(action: Action, session: &SessionMetaData, os_input: &dyn Server
 }
 
 pub(crate) fn route_thread_main(
-    sessions: Arc<RwLock<Option<SessionMetaData>>>,
+    session_data: Arc<RwLock<Option<SessionMetaData>>>,
     os_input: Box<dyn ServerOsApi>,
     to_server: SenderWithContext<ServerInstruction>,
 ) {
     loop {
         let (instruction, err_ctx) = os_input.recv_from_client();
         err_ctx.update_thread_ctx();
-        let rlocked_sessions = sessions.read().unwrap();
+        let rlocked_sessions = session_data.read().unwrap();
         match instruction {
-            ClientToServerMsg::ClientExit => {
+            ClientToServerMsg::ClientExit | ClientToServerMsg::DetachSession => {
                 to_server.send(instruction.into()).unwrap();
                 break;
             }

zellij-server/src/screen.rs

@@ -3,6 +3,7 @@
 use std::collections::BTreeMap;
 use std::os::unix::io::RawFd;
 use std::str;
+use std::sync::{Arc, RwLock};
 
 use zellij_utils::zellij_tile;
 
@@ -13,7 +14,7 @@ use crate::{
     thread_bus::Bus,
     ui::layout::Layout,
     wasm_vm::PluginInstruction,
-    ServerInstruction,
+    ServerInstruction, SessionState,
 };
 use zellij_tile::data::{Event, InputMode, ModeInfo, Palette, PluginCapabilities, TabInfo};
 use zellij_utils::{
@@ -137,6 +138,7 @@ pub(crate) struct Screen {
     mode_info: ModeInfo,
     input_mode: InputMode,
     colors: Palette,
+    session_state: Arc<RwLock<SessionState>>,
 }
 
 impl Screen {
@@ -147,6 +149,7 @@ impl Screen {
         max_panes: Option<usize>,
         mode_info: ModeInfo,
         input_mode: InputMode,
+        session_state: Arc<RwLock<SessionState>>,
     ) -> Self {
         Screen {
             bus,
@@ -157,6 +160,7 @@ impl Screen {
             tabs: BTreeMap::new(),
             mode_info,
             input_mode,
+            session_state,
         }
     }
 
@@ -177,6 +181,7 @@ impl Screen {
             self.mode_info.clone(),
             self.input_mode,
             self.colors,
+            self.session_state.clone(),
         );
         self.active_tab_index = Some(tab_index);
         self.tabs.insert(tab_index, tab);
@@ -261,10 +266,12 @@ impl Screen {
             .unwrap();
         if self.tabs.is_empty() {
             self.active_tab_index = None;
+            if *self.session_state.read().unwrap() == SessionState::Attached {
                 self.bus
                     .senders
                     .send_to_server(ServerInstruction::Render(None))
                     .unwrap();
+            }
         } else {
             for t in self.tabs.values_mut() {
                 if t.position > active_tab.position {
@@ -286,6 +293,9 @@ impl Screen {
 
     /// Renders this [`Screen`], which amounts to rendering its active [`Tab`].
     pub fn render(&mut self) {
+        if *self.session_state.read().unwrap() != SessionState::Attached {
+            return;
+        }
         if let Some(active_tab) = self.get_active_tab_mut() {
             if active_tab.get_active_pane().is_some() {
                 active_tab.render();
@@ -333,6 +343,7 @@ impl Screen {
             self.mode_info.clone(),
             self.input_mode,
             self.colors,
+            self.session_state.clone(),
         );
         tab.apply_layout(layout, new_pids);
         self.active_tab_index = Some(tab_index);
@@ -390,6 +401,7 @@ pub(crate) fn screen_thread_main(
     max_panes: Option<usize>,
     client_attributes: ClientAttributes,
     config_options: Box<Options>,
+    session_state: Arc<RwLock<SessionState>>,
 ) {
     let capabilities = config_options.simplified_ui;
 
@@ -405,6 +417,7 @@ pub(crate) fn screen_thread_main(
             ..ModeInfo::default()
         },
         InputMode::Normal,
+        session_state,
     );
     loop {
         let (event, mut err_ctx) = screen

zellij-server/src/tab.rs

@@ -10,11 +10,11 @@ use crate::{
     thread_bus::ThreadSenders,
     ui::{boundaries::Boundaries, layout::Layout, pane_resizer::PaneResizer},
     wasm_vm::PluginInstruction,
-    ServerInstruction,
+    ServerInstruction, SessionState,
 };
 use serde::{Deserialize, Serialize};
 use std::os::unix::io::RawFd;
-use std::sync::mpsc::channel;
+use std::sync::{mpsc::channel, Arc, RwLock};
 use std::time::Instant;
 use std::{
     cmp::Reverse,
@@ -74,6 +74,7 @@ pub(crate) struct Tab {
     pub senders: ThreadSenders,
     synchronize_is_active: bool,
     should_clear_display_before_rendering: bool,
+    session_state: Arc<RwLock<SessionState>>,
     pub mode_info: ModeInfo,
     pub input_mode: InputMode,
     pub colors: Palette,
@@ -242,6 +243,7 @@ impl Tab {
         mode_info: ModeInfo,
         input_mode: InputMode,
         colors: Palette,
+        session_state: Arc<RwLock<SessionState>>,
     ) -> Self {
         let panes = if let Some(PaneId::Terminal(pid)) = pane_id {
             let new_terminal = TerminalPane::new(pid, *full_screen_ws, colors);
@@ -273,6 +275,7 @@ impl Tab {
             mode_info,
             input_mode,
             colors,
+            session_state,
         }
     }
 
@@ -722,7 +725,9 @@ impl Tab {
         self.panes.iter().any(|(_, p)| p.contains_widechar())
     }
     pub fn render(&mut self) {
-        if self.active_terminal.is_none() {
+        if self.active_terminal.is_none()
+            || *self.session_state.read().unwrap() != SessionState::Attached
+        {
             // we might not have an active terminal if we closed the last pane
             // in that case, we should not render as the app is exiting
             return;

zellij-utils/src/errors.rs

@@ -260,4 +260,5 @@ pub enum ServerContext {
     UnblockInputThread,
     ClientExit,
     Error,
+    DetachSession,
 }

zellij-utils/src/ipc.rs

@@ -58,6 +58,7 @@ pub enum ClientToServerMsg {
     TerminalResize(PositionAndSize),
     NewClient(ClientAttributes, Box<CliArgs>, Box<Options>),
     Action(Action),
+    DetachSession,
 }
 
 // Types of messages sent from the server to the client