Add a "lock-in" delay to LRU window order

This patch introduces the following:
- a configurable duration has to go by before a focus event results in a
  window's timestamp being updated. In other words, the LRU order only
  changes when a window keeps the focus long enough.
- focus timestamps for each window are moved from `extra_props` to a
  dedicated `FocusData` struct that lives in focus.rs
- swayrd configuration has an added "focus" section in which the
  "lock-in" delay can be configured (with the `lockin_delay` key).

All together, this allows the user to navigate through windows (with the
mouse and/or keyboard) without updating the LRU history unless a window
is lingered in.  This avoids "polluting" the history and allows more
efficient jumping back-and-forth with prev/next-window commands.

swayr/src/cmds.rs

@@ -16,6 +16,8 @@
 //! Functions and data structures of the swayr client.
 
 use crate::config as cfg;
+use crate::focus::FocusData;
+use crate::focus::FocusMessage;
 use crate::layout;
 use crate::shared::ipc;
 use crate::shared::ipc::NodeMethods;
@@ -26,10 +28,6 @@ use once_cell::sync::Lazy;
 use rand::prelude::SliceRandom;
 use regex::Regex;
 use serde::{Deserialize, Serialize};
-use std::collections::HashMap;
-use std::sync::atomic;
-use std::sync::Arc;
-use std::sync::RwLock;
 use swayipc as s;
 
 pub fn run_sway_command_1(cmd: &str) {
@@ -227,7 +225,7 @@ impl SwayrCommand {
 
 pub struct ExecSwayrCmdArgs<'a> {
     pub cmd: &'a SwayrCommand,
-    pub extra_props: Arc<RwLock<HashMap<i64, t::ExtraProps>>>,
+    pub focus_data: &'a FocusData,
 }
 
 impl DisplayFormat for SwayrCommand {
@@ -247,86 +245,62 @@ fn always_true(_x: &t::DisplayNode) -> bool {
     true
 }
 
-static IN_NEXT_PREV_WINDOW_SEQ: atomic::AtomicBool =
-    atomic::AtomicBool::new(false);
-
 pub fn exec_swayr_cmd(args: ExecSwayrCmdArgs) {
-    let props = args.extra_props;
+    let fdata = args.focus_data;
 
     if args.cmd.is_prev_next_window_variant() {
-        let before =
-            IN_NEXT_PREV_WINDOW_SEQ.swap(true, atomic::Ordering::SeqCst);
-        if !before {
-            let mut map = props.write().unwrap();
-            for val in map.values_mut() {
-                val.last_focus_tick_for_next_prev_seq = val.last_focus_tick;
-            }
-        }
+        fdata.send(FocusMessage::TickUpdateInhibit);
     } else {
-        IN_NEXT_PREV_WINDOW_SEQ.store(false, atomic::Ordering::SeqCst);
+        fdata.send(FocusMessage::TickUpdateActivate);
     }
 
     match args.cmd {
         SwayrCommand::Nop => {}
         SwayrCommand::SwitchToUrgentOrLRUWindow => {
-            switch_to_urgent_or_lru_window(&*props.read().unwrap())
+            switch_to_urgent_or_lru_window(fdata)
         }
         SwayrCommand::SwitchToAppOrUrgentOrLRUWindow { name } => {
-            switch_to_app_or_urgent_or_lru_window(
-                Some(name),
-                &*props.read().unwrap(),
-            )
+            switch_to_app_or_urgent_or_lru_window(Some(name), fdata)
         }
         SwayrCommand::SwitchToMarkOrUrgentOrLRUWindow { con_mark } => {
-            switch_to_mark_or_urgent_or_lru_window(
-                Some(con_mark),
-                &*props.read().unwrap(),
-            )
-        }
-        SwayrCommand::SwitchWindow => switch_window(&*props.read().unwrap()),
-        SwayrCommand::SwitchWorkspace => {
-            switch_workspace(&*props.read().unwrap())
+            switch_to_mark_or_urgent_or_lru_window(Some(con_mark), fdata)
         }
-        SwayrCommand::SwitchOutput => switch_output(&*props.read().unwrap()),
+        SwayrCommand::SwitchWindow => switch_window(fdata),
+        SwayrCommand::SwitchWorkspace => switch_workspace(fdata),
+        SwayrCommand::SwitchOutput => switch_output(),
         SwayrCommand::SwitchWorkspaceOrWindow => {
-            switch_workspace_or_window(&*props.read().unwrap())
+            switch_workspace_or_window(fdata)
         }
         SwayrCommand::SwitchWorkspaceContainerOrWindow => {
-            switch_workspace_container_or_window(&*props.read().unwrap())
-        }
-        SwayrCommand::SwitchTo => switch_to(&*props.read().unwrap()),
-        SwayrCommand::QuitWindow { kill } => {
-            quit_window(&*props.read().unwrap(), *kill)
-        }
-        SwayrCommand::QuitWorkspaceOrWindow => {
-            quit_workspace_or_window(&*props.read().unwrap())
+            switch_workspace_container_or_window(fdata)
         }
+        SwayrCommand::SwitchTo => switch_to(fdata),
+        SwayrCommand::QuitWindow { kill } => quit_window(fdata, *kill),
+        SwayrCommand::QuitWorkspaceOrWindow => quit_workspace_or_window(fdata),
         SwayrCommand::QuitWorkspaceContainerOrWindow => {
-            quit_workspace_container_or_window(&*props.read().unwrap())
+            quit_workspace_container_or_window(fdata)
         }
         SwayrCommand::MoveFocusedToWorkspace => {
-            move_focused_to_workspace(&*props.read().unwrap())
-        }
-        SwayrCommand::MoveFocusedTo => move_focused_to(&*props.read().unwrap()),
-        SwayrCommand::SwapFocusedWith => {
-            swap_focused_with(&*props.read().unwrap())
+            move_focused_to_workspace(fdata)
         }
+        SwayrCommand::MoveFocusedTo => move_focused_to(fdata),
+        SwayrCommand::SwapFocusedWith => swap_focused_with(fdata),
         SwayrCommand::NextWindow { windows } => focus_window_in_direction(
             Direction::Forward,
             windows,
-            &*props.read().unwrap(),
+            fdata,
             Box::new(always_true),
         ),
         SwayrCommand::PrevWindow { windows } => focus_window_in_direction(
             Direction::Backward,
             windows,
-            &*props.read().unwrap(),
+            fdata,
             Box::new(always_true),
         ),
         SwayrCommand::NextTiledWindow { windows } => focus_window_in_direction(
             Direction::Forward,
             windows,
-            &*props.read().unwrap(),
+            fdata,
             Box::new(|dn: &t::DisplayNode| {
                 !dn.node.is_floating()
                     && dn.tree.is_child_of_tiled_container(dn.node.id)
@@ -335,7 +309,7 @@ pub fn exec_swayr_cmd(args: ExecSwayrCmdArgs) {
         SwayrCommand::PrevTiledWindow { windows } => focus_window_in_direction(
             Direction::Backward,
             windows,
-            &*props.read().unwrap(),
+            fdata,
             Box::new(|dn: &t::DisplayNode| {
                 !dn.node.is_floating()
                     && dn.tree.is_child_of_tiled_container(dn.node.id)
@@ -345,7 +319,7 @@ pub fn exec_swayr_cmd(args: ExecSwayrCmdArgs) {
             focus_window_in_direction(
                 Direction::Forward,
                 windows,
-                &*props.read().unwrap(),
+                fdata,
                 Box::new(|dn: &t::DisplayNode| {
                     !dn.node.is_floating()
                         && dn
@@ -358,7 +332,7 @@ pub fn exec_swayr_cmd(args: ExecSwayrCmdArgs) {
             focus_window_in_direction(
                 Direction::Backward,
                 windows,
-                &*props.read().unwrap(),
+                fdata,
                 Box::new(|dn: &t::DisplayNode| {
                     !dn.node.is_floating()
                         && dn
@@ -371,7 +345,7 @@ pub fn exec_swayr_cmd(args: ExecSwayrCmdArgs) {
             focus_window_in_direction(
                 Direction::Forward,
                 windows,
-                &*props.read().unwrap(),
+                fdata,
                 Box::new(|dn: &t::DisplayNode| dn.node.is_floating()),
             )
         }
@@ -379,7 +353,7 @@ pub fn exec_swayr_cmd(args: ExecSwayrCmdArgs) {
             focus_window_in_direction(
                 Direction::Backward,
                 windows,
-                &*props.read().unwrap(),
+                fdata,
                 Box::new(|dn: &t::DisplayNode| dn.node.is_floating()),
             )
         }
@@ -387,14 +361,14 @@ pub fn exec_swayr_cmd(args: ExecSwayrCmdArgs) {
             focus_window_of_same_layout_in_direction(
                 Direction::Forward,
                 windows,
-                &*props.read().unwrap(),
+                fdata,
             )
         }
         SwayrCommand::PrevWindowOfSameLayout { windows } => {
             focus_window_of_same_layout_in_direction(
                 Direction::Backward,
                 windows,
-                &*props.read().unwrap(),
+                fdata,
             )
         }
         SwayrCommand::TileWorkspace { floating } => {
@@ -473,7 +447,7 @@ pub fn exec_swayr_cmd(args: ExecSwayrCmdArgs) {
             {
                 exec_swayr_cmd(ExecSwayrCmdArgs {
                     cmd: c,
-                    extra_props: props,
+                    focus_data: args.focus_data,
                 });
             }
         }
@@ -495,19 +469,17 @@ pub fn get_outputs() -> Vec<s::Output> {
     }
 }
 
-pub fn switch_to_urgent_or_lru_window(
-    extra_props: &HashMap<i64, t::ExtraProps>,
-) {
-    switch_to_app_or_urgent_or_lru_window(None, extra_props)
+pub fn switch_to_urgent_or_lru_window(fdata: &FocusData) {
+    switch_to_app_or_urgent_or_lru_window(None, fdata)
 }
 
 pub fn switch_to_app_or_urgent_or_lru_window(
     name: Option<&str>,
-    extra_props: &HashMap<i64, t::ExtraProps>,
+    fdata: &FocusData,
 ) {
     let root = ipc::get_root_node(false);
-    let tree = t::get_tree(&root, extra_props);
-    let wins = tree.get_windows();
+    let tree = t::get_tree(&root);
+    let wins = tree.get_windows(fdata);
     let app_win =
         name.and_then(|n| wins.iter().find(|w| w.node.get_app_name() == n));
     focus_win_if_not_focused(app_win, wins.get(0))
@@ -515,11 +487,11 @@ pub fn switch_to_app_or_urgent_or_lru_window(
 
 pub fn switch_to_mark_or_urgent_or_lru_window(
     con_mark: Option<&str>,
-    extra_props: &HashMap<i64, t::ExtraProps>,
+    fdata: &FocusData,
 ) {
     let root = ipc::get_root_node(false);
-    let tree = t::get_tree(&root, extra_props);
-    let wins = tree.get_windows();
+    let tree = t::get_tree(&root);
+    let wins = tree.get_windows(fdata);
     let marked_win = con_mark.and_then(|mark| {
         wins.iter()
             .find(|w| w.node.marks.contains(&mark.to_owned()))
@@ -612,50 +584,48 @@ fn select_and_focus(prompt: &str, choices: &[t::DisplayNode]) {
     }
 }
 
-pub fn switch_window(extra_props: &HashMap<i64, t::ExtraProps>) {
+pub fn switch_window(fdata: &FocusData) {
     let root = ipc::get_root_node(true);
-    let tree = t::get_tree(&root, extra_props);
-    select_and_focus("Select window", &tree.get_windows());
+    let tree = t::get_tree(&root);
+    select_and_focus("Select window", &tree.get_windows(fdata));
 }
 
-pub fn switch_workspace(extra_props: &HashMap<i64, t::ExtraProps>) {
+pub fn switch_workspace(fdata: &FocusData) {
     let root = ipc::get_root_node(false);
-    let tree = t::get_tree(&root, extra_props);
-    select_and_focus("Select workspace", &tree.get_workspaces());
+    let tree = t::get_tree(&root);
+    select_and_focus("Select workspace", &tree.get_workspaces(fdata));
 }
 
-pub fn switch_output(extra_props: &HashMap<i64, t::ExtraProps>) {
+pub fn switch_output() {
     let root = ipc::get_root_node(false);
-    let tree = t::get_tree(&root, extra_props);
+    let tree = t::get_tree(&root);
     select_and_focus("Select output", &tree.get_outputs());
 }
 
-pub fn switch_workspace_or_window(extra_props: &HashMap<i64, t::ExtraProps>) {
+pub fn switch_workspace_or_window(fdata: &FocusData) {
     let root = ipc::get_root_node(true);
-    let tree = t::get_tree(&root, extra_props);
+    let tree = t::get_tree(&root);
     select_and_focus(
         "Select workspace or window",
-        &tree.get_workspaces_and_windows(),
+        &tree.get_workspaces_and_windows(fdata),
     );
 }
 
-pub fn switch_workspace_container_or_window(
-    extra_props: &HashMap<i64, t::ExtraProps>,
-) {
+pub fn switch_workspace_container_or_window(fdata: &FocusData) {
     let root = ipc::get_root_node(true);
-    let tree = t::get_tree(&root, extra_props);
+    let tree = t::get_tree(&root);
     select_and_focus(
         "Select workspace, container or window",
-        &tree.get_workspaces_containers_and_windows(),
+        &tree.get_workspaces_containers_and_windows(fdata),
     );
 }
 
-pub fn switch_to(extra_props: &HashMap<i64, t::ExtraProps>) {
+pub fn switch_to(fdata: &FocusData) {
     let root = ipc::get_root_node(true);
-    let tree = t::get_tree(&root, extra_props);
+    let tree = t::get_tree(&root);
     select_and_focus(
         "Select output, workspace, container or window",
-        &tree.get_outputs_workspaces_containers_and_windows(),
+        &tree.get_outputs_workspaces_containers_and_windows(fdata),
     );
 }
 
@@ -697,30 +667,28 @@ fn select_and_quit(prompt: &str, choices: &[t::DisplayNode], kill: bool) {
     }
 }
 
-pub fn quit_window(extra_props: &HashMap<i64, t::ExtraProps>, kill: bool) {
+pub fn quit_window(fdata: &FocusData, kill: bool) {
     let root = ipc::get_root_node(true);
-    let tree = t::get_tree(&root, extra_props);
-    select_and_quit("Quit window", &tree.get_windows(), kill);
+    let tree = t::get_tree(&root);
+    select_and_quit("Quit window", &tree.get_windows(fdata), kill);
 }
 
-pub fn quit_workspace_or_window(extra_props: &HashMap<i64, t::ExtraProps>) {
+pub fn quit_workspace_or_window(fdata: &FocusData) {
     let root = ipc::get_root_node(true);
-    let tree = t::get_tree(&root, extra_props);
+    let tree = t::get_tree(&root);
     select_and_quit(
         "Quit workspace or window",
-        &tree.get_workspaces_and_windows(),
+        &tree.get_workspaces_and_windows(fdata),
         false,
     );
 }
 
-pub fn quit_workspace_container_or_window(
-    extra_props: &HashMap<i64, t::ExtraProps>,
-) {
+pub fn quit_workspace_container_or_window(fdata: &FocusData) {
     let root = ipc::get_root_node(true);
-    let tree = t::get_tree(&root, extra_props);
+    let tree = t::get_tree(&root);
     select_and_quit(
         "Quit workspace, container or window",
-        &tree.get_workspaces_containers_and_windows(),
+        &tree.get_workspaces_containers_and_windows(fdata),
         false,
     );
 }
@@ -783,30 +751,30 @@ fn select_and_move_focused_to(prompt: &str, choices: &[t::DisplayNode]) {
     }
 }
 
-pub fn move_focused_to_workspace(extra_props: &HashMap<i64, t::ExtraProps>) {
+pub fn move_focused_to_workspace(fdata: &FocusData) {
     let root = ipc::get_root_node(true);
-    let tree = t::get_tree(&root, extra_props);
-    select_and_move_focused_to(
+    let tree = t::get_tree(&root);
+select_and_move_focused_to(
         "Move focused container to workspace",
-        &tree.get_workspaces(),
+        &tree.get_workspaces(fdata),
     );
 }
 
-pub fn move_focused_to(extra_props: &HashMap<i64, t::ExtraProps>) {
+pub fn move_focused_to(fdata: &FocusData) {
     let root = ipc::get_root_node(true);
-    let tree = t::get_tree(&root, extra_props);
+    let tree = t::get_tree(&root);
     select_and_move_focused_to(
         "Move focused container to workspace or container",
-        &tree.get_outputs_workspaces_containers_and_windows(),
+        &tree.get_outputs_workspaces_containers_and_windows(fdata),
     );
 }
 
-pub fn swap_focused_with(extra_props: &HashMap<i64, t::ExtraProps>) {
+pub fn swap_focused_with(fdata: &FocusData) {
     let root = ipc::get_root_node(true);
-    let tree = t::get_tree(&root, extra_props);
+    let tree = t::get_tree(&root);
     match util::select_from_menu(
         "Swap focused with",
-        &tree.get_workspaces_containers_and_windows(),
+        &tree.get_workspaces_containers_and_windows(fdata),
     ) {
         Ok(tn) => match tn.node.get_type() {
             ipc::Type::Workspace | ipc::Type::Container | ipc::Type::Window => {
@@ -835,12 +803,12 @@ pub enum Direction {
 pub fn focus_window_in_direction(
     dir: Direction,
     consider_wins: &ConsiderWindows,
-    extra_props: &HashMap<i64, t::ExtraProps>,
+    fdata: &FocusData,
     pred: Box<dyn Fn(&t::DisplayNode) -> bool>,
 ) {
     let root = ipc::get_root_node(false);
-    let tree = t::get_tree(&root, extra_props);
-    let mut wins = tree.get_windows();
+    let tree = t::get_tree(&root);
+    let mut wins = tree.get_windows(fdata);
 
     if consider_wins == &ConsiderWindows::CurrentWorkspace {
         let cur_ws = tree.get_current_workspace();
@@ -859,8 +827,8 @@ pub fn focus_window_in_direction(
     }
 
     wins.sort_by(|a, b| {
-        let lru_a = tree.last_focus_tick_for_next_prev_seq(a.node.id);
-        let lru_b = tree.last_focus_tick_for_next_prev_seq(b.node.id);
+        let lru_a = fdata.last_focus_tick(a.node.id);
+        let lru_b = fdata.last_focus_tick(b.node.id);
         lru_a.cmp(&lru_b).reverse()
     });
 
@@ -890,18 +858,18 @@ pub fn focus_window_in_direction(
 pub fn focus_window_of_same_layout_in_direction(
     dir: Direction,
     consider_wins: &ConsiderWindows,
-    extra_props: &HashMap<i64, t::ExtraProps>,
+    fdata: &FocusData,
 ) {
     let root = ipc::get_root_node(false);
-    let tree = t::get_tree(&root, extra_props);
-    let wins = tree.get_windows();
+    let tree = t::get_tree(&root);
+    let wins = tree.get_windows(fdata);
     let cur_win = wins.iter().find(|w| w.node.focused);
 
     if let Some(cur_win) = cur_win {
         focus_window_in_direction(
             dir,
             consider_wins,
-            extra_props,
+            fdata,
             if cur_win.node.is_floating() {
                 Box::new(|dn| dn.node.is_floating())
             } else if !cur_win.node.is_floating()

swayr/src/config.rs

@@ -18,12 +18,14 @@
 use crate::shared::cfg;
 use serde::{Deserialize, Serialize};
 use std::collections::HashMap;
+use std::time::Duration;
 
 #[derive(Debug, Serialize, Deserialize)]
 pub struct Config {
     menu: Option<Menu>,
     format: Option<Format>,
     layout: Option<Layout>,
+    focus: Option<Focus>,
 }
 
 fn tilde_expand_file_names(file_names: Vec<String>) -> Vec<String> {
@@ -155,6 +157,16 @@ impl Config {
             .or_else(|| Layout::default().auto_tile_min_window_width_per_output_width_as_map())
             .expect("No layout.auto_tile_min_window_width_per_output_width defined.")
     }
+
+    pub fn get_focus_lockin_delay(&self) -> Duration {
+        Duration::from_millis(
+            self.focus
+                .as_ref()
+                .and_then(|f| f.lockin_delay)
+                .or_else(|| Focus::default().lockin_delay)
+                .expect("No focus.lockin_delay defined."),
+        )
+    }
 }
 
 #[derive(Debug, Serialize, Deserialize)]
@@ -199,6 +211,11 @@ impl Layout {
     }
 }
 
+#[derive(Debug, Serialize, Deserialize)]
+pub struct Focus {
+    lockin_delay: Option<u64>,
+}
+
 impl Default for Menu {
     fn default() -> Self {
         Menu {
@@ -290,12 +307,21 @@ impl Default for Layout {
     }
 }
 
+impl Default for Focus {
+    fn default() -> Self {
+        Self {
+            lockin_delay: Some(750),
+        }
+    }
+}
+
 impl Default for Config {
     fn default() -> Self {
         Config {
             menu: Some(Menu::default()),
             format: Some(Format::default()),
             layout: Some(Layout::default()),
+            focus: Some(Focus::default()),
         }
     }
 }

swayr/src/daemon.rs

@@ -16,28 +16,47 @@
 //! Functions and data structures of the swayrd daemon.
 
 use crate::cmds;
-use crate::config;
+use crate::config::{self, Config};
+use crate::focus::FocusData;
+use crate::focus::FocusEvent;
+use crate::focus::FocusMessage;
 use crate::layout;
-use crate::tree as t;
 use crate::util;
 use std::collections::HashMap;
 use std::io::Read;
 use std::os::unix::net::{UnixListener, UnixStream};
+use std::sync::mpsc;
 use std::sync::Arc;
 use std::sync::RwLock;
 use std::thread;
+use std::time::Duration;
 use swayipc as s;
 
 pub fn run_daemon() {
-    let extra_props: Arc<RwLock<HashMap<i64, t::ExtraProps>>> =
-        Arc::new(RwLock::new(HashMap::new()));
-    let extra_props_for_ev_handler = extra_props.clone();
+    let (focus_tx, focus_rx) = mpsc::channel();
+    let fdata = FocusData {
+        focus_tick_by_id: Arc::new(RwLock::new(HashMap::new())),
+        focus_chan: focus_tx,
+    };
 
+    let config = config::load_config();
+    let lockin_delay = config.get_focus_lockin_delay();
+
+    {
+        let fdata = fdata.clone();
         thread::spawn(move || {
-        monitor_sway_events(extra_props_for_ev_handler);
+            monitor_sway_events(fdata, &config);
         });
+    }
+
+    {
+        let fdata = fdata.clone();
+        thread::spawn(move || {
+            focus_lock_in_handler(focus_rx, fdata, lockin_delay);
+        });
+    }
 
-    serve_client_requests(extra_props);
+    serve_client_requests(fdata);
 }
 
 fn connect_and_subscribe() -> s::Fallible<s::EventStream> {
@@ -48,10 +67,7 @@ fn connect_and_subscribe() -> s::Fallible<s::EventStream> {
     ])
 }
 
-pub fn monitor_sway_events(
-    extra_props: Arc<RwLock<HashMap<i64, t::ExtraProps>>>,
-) {
-    let config = config::load_config();
+pub fn monitor_sway_events(fdata: FocusData, config: &Config) {
     let mut focus_counter = 0;
     let mut resets = 0;
     let max_resets = 10;
@@ -75,21 +91,19 @@ pub fn monitor_sway_events(
                     match ev_result {
                         Ok(ev) => match ev {
                             s::Event::Window(win_ev) => {
-                                let extra_props_clone = extra_props.clone();
                                 focus_counter += 1;
                                 show_extra_props_state = handle_window_event(
                                     win_ev,
-                                    extra_props_clone,
-                                    &config,
+                                    &fdata,
+                                    config,
                                     focus_counter,
                                 );
                             }
                             s::Event::Workspace(ws_ev) => {
-                                let extra_props_clone = extra_props.clone();
                                 focus_counter += 1;
                                 show_extra_props_state = handle_workspace_event(
                                     ws_ev,
-                                    extra_props_clone,
+                                    &fdata,
                                     focus_counter,
                                 );
                             }
@@ -114,7 +128,7 @@ pub fn monitor_sway_events(
                     if show_extra_props_state {
                         log::debug!(
                             "New extra_props state:\n{:#?}",
-                            *extra_props.read().unwrap()
+                            *fdata.focus_tick_by_id.read().unwrap()
                         );
                     }
                 }
@@ -126,7 +140,7 @@ pub fn monitor_sway_events(
 
 fn handle_window_event(
     ev: Box<s::WindowEvent>,
-    extra_props: Arc<RwLock<HashMap<i64, t::ExtraProps>>>,
+    fdata: &FocusData,
     config: &config::Config,
     focus_val: u64,
 ) -> bool {
@@ -136,18 +150,21 @@ fn handle_window_event(
     match change {
         s::WindowChange::Focus => {
             layout::maybe_auto_tile(config);
-            update_last_focus_tick(container.id, extra_props, focus_val);
+            fdata.send(FocusMessage::FocusEvent(FocusEvent {
+                node_id: container.id,
+                ev_focus_ctr: focus_val,
+            }));
             log::debug!("Handled window event type {:?}", change);
             true
         }
         s::WindowChange::New => {
             layout::maybe_auto_tile(config);
-            update_last_focus_tick(container.id, extra_props, focus_val);
+            fdata.ensure_id(container.id);
             log::debug!("Handled window event type {:?}", change);
             true
         }
         s::WindowChange::Close => {
-            remove_extra_props(container.id, extra_props);
+            fdata.remove_focus_data(container.id);
             layout::maybe_auto_tile(config);
             log::debug!("Handled window event type {:?}", change);
             true
@@ -166,7 +183,7 @@ fn handle_window_event(
 
 fn handle_workspace_event(
     ev: Box<s::WorkspaceEvent>,
-    extra_props: Arc<RwLock<HashMap<i64, t::ExtraProps>>>,
+    fdata: &FocusData,
     focus_val: u64,
 ) -> bool {
     let s::WorkspaceEvent {
@@ -177,20 +194,19 @@ fn handle_workspace_event(
     } = *ev;
     match change {
         s::WorkspaceChange::Init | s::WorkspaceChange::Focus => {
-            update_last_focus_tick(
-                current
+            let id = current
                 .expect("No current in Init or Focus workspace event")
-                    .id,
-                extra_props,
-                focus_val,
-            );
+                .id;
+            fdata.send(FocusMessage::FocusEvent(FocusEvent {
+                node_id: id,
+                ev_focus_ctr: focus_val,
+            }));
             log::debug!("Handled workspace event type {:?}", change);
             true
         }
         s::WorkspaceChange::Empty => {
-            remove_extra_props(
+            fdata.remove_focus_data(
                 current.expect("No current in Empty workspace event").id,
-                extra_props,
             );
             log::debug!("Handled workspace event type {:?}", change);
             true
@@ -199,35 +215,7 @@ fn handle_workspace_event(
     }
 }
 
-fn update_last_focus_tick(
-    id: i64,
-    extra_props: Arc<RwLock<HashMap<i64, t::ExtraProps>>>,
-    focus_val: u64,
-) {
-    let mut write_lock = extra_props.write().unwrap();
-    if let Some(wp) = write_lock.get_mut(&id) {
-        wp.last_focus_tick = focus_val;
-    } else {
-        write_lock.insert(
-            id,
-            t::ExtraProps {
-                last_focus_tick: focus_val,
-                last_focus_tick_for_next_prev_seq: focus_val,
-            },
-        );
-    }
-}
-
-fn remove_extra_props(
-    id: i64,
-    extra_props: Arc<RwLock<HashMap<i64, t::ExtraProps>>>,
-) {
-    extra_props.write().unwrap().remove(&id);
-}
-
-pub fn serve_client_requests(
-    extra_props: Arc<RwLock<HashMap<i64, t::ExtraProps>>>,
-) {
+pub fn serve_client_requests(fdata: FocusData) {
     match std::fs::remove_file(util::get_swayr_socket_path()) {
         Ok(()) => log::debug!("Deleted stale socket from previous run."),
         Err(e) => log::error!("Could not delete socket:\n{:?}", e),
@@ -238,7 +226,7 @@ pub fn serve_client_requests(
             for stream in listener.incoming() {
                 match stream {
                     Ok(stream) => {
-                        handle_client_request(stream, extra_props.clone());
+                        handle_client_request(stream, &fdata);
                     }
                     Err(err) => {
                         log::error!("Error handling client request: {}", err);
@@ -253,16 +241,13 @@ pub fn serve_client_requests(
     }
 }
 
-fn handle_client_request(
-    mut stream: UnixStream,
-    extra_props: Arc<RwLock<HashMap<i64, t::ExtraProps>>>,
-) {
+fn handle_client_request(mut stream: UnixStream, fdata: &FocusData) {
     let mut cmd_str = String::new();
     if stream.read_to_string(&mut cmd_str).is_ok() {
         if let Ok(cmd) = serde_json::from_str::<cmds::SwayrCommand>(&cmd_str) {
             cmds::exec_swayr_cmd(cmds::ExecSwayrCmdArgs {
                 cmd: &cmd,
-                extra_props,
+                focus_data: fdata,
             });
         } else {
             log::error!(
@@ -274,3 +259,110 @@ fn handle_client_request(
         log::error!("Could not read command from client.");
     }
 }
+
+#[derive(Debug)]
+enum InhibitState {
+    FocusInhibit,
+    FocusActive,
+}
+
+impl InhibitState {
+    pub fn set(&mut self) {
+        if let InhibitState::FocusActive = self {
+            log::debug!("Inhibiting tick focus updates");
+            *self = InhibitState::FocusInhibit;
+        }
+    }
+
+    pub fn clear(&mut self) {
+        if let InhibitState::FocusInhibit = self {
+            log::debug!("Activating tick focus updates");
+            *self = InhibitState::FocusActive;
+        }
+    }
+}
+
+fn focus_lock_in_handler(
+    focus_chan: mpsc::Receiver<FocusMessage>,
+    fdata: FocusData,
+    lockin_delay: Duration,
+) {
+    // Focus event that has not yet been locked-in to the LRU order
+    let mut pending_fev: Option<FocusEvent> = None;
+
+    // Toggle to inhibit LRU focus updates
+    let mut inhibit = InhibitState::FocusActive;
+
+    let update_focus = |fev: Option<FocusEvent>| {
+        if let Some(fev) = fev {
+            log::debug!("Locking-in focus on {}", fev.node_id);
+            fdata.update_last_focus_tick(
+                fev.node_id,
+                fev.ev_focus_ctr,
+            )
+        }
+    };
+
+    // outer loop, waiting for focus events
+    loop {
+        let fmsg = match focus_chan.recv() {
+            Ok(fmsg) => fmsg,
+            Err(mpsc::RecvError) => return,
+        };
+
+        let mut fev = match fmsg {
+            FocusMessage::TickUpdateInhibit => {
+                inhibit.set();
+                continue;
+            }
+            FocusMessage::TickUpdateActivate => {
+                inhibit.clear();
+                update_focus(pending_fev.take());
+                continue
+            }
+            FocusMessage::FocusEvent(fev) => {
+                if let InhibitState::FocusInhibit = inhibit {
+                    // update the pending event but take no further action
+                    pending_fev = Some(fev);
+                    continue;
+                }
+                fev
+            }
+        };
+
+        // Inner loop, waiting for the lock-in delay to expire
+        loop {
+            let fmsg = match focus_chan.recv_timeout(lockin_delay) {
+                Ok(fmsg) => fmsg,
+                Err(mpsc::RecvTimeoutError::Timeout) => {
+                    update_focus(Some(fev));
+                    break; // return to outer loop
+                }
+                Err(mpsc::RecvTimeoutError::Disconnected) => return,
+            };
+
+            match fmsg {
+                FocusMessage::TickUpdateInhibit => {
+                    // inhibit requested before currently focused container
+                    // was locked-in, set it as pending in case no other
+                    // focus changes are made while updates remain inhibited
+                    inhibit.set();
+                    pending_fev = Some(fev);
+                    break; // return to outer loop with a preset pending_fev
+                }
+                FocusMessage::TickUpdateActivate => {
+                    // updates reactivated while we were waiting to lockin
+                    // Immediately lockin fev
+                    inhibit.clear();
+                    update_focus(Some(fev));
+                    break;
+                }
+                FocusMessage::FocusEvent(new_fev) => {
+                    // start a new wait (inner) loop with the most recent
+                    // focus event
+                    fev = new_fev;
+                }
+            }
+        }
+    }
+}

swayr/src/focus.rs

@@ -0,0 +1,90 @@
+// Copyright (C) 2021-2022  Tassilo Horn <tsdh@gnu.org>
+//
+// This program is free software: you can redistribute it and/or modify it
+// under the terms of the GNU General Public License as published by the Free
+// Software Foundation, either version 3 of the License, or (at your option)
+// any later version.
+//
+// This program is distributed in the hope that it will be useful, but WITHOUT
+// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+// more details.
+//
+// You should have received a copy of the GNU General Public License along with
+// this program.  If not, see <https://www.gnu.org/licenses/>.
+
+//! Structure to hold window focus timestamps used by swayrd
+
+use std::sync::mpsc;
+use std::sync::Arc;
+use std::sync::RwLock;
+use std::collections::HashMap;
+
+/// Data tracking most recent focus events for Sway windows/containers
+#[derive(Clone)]
+pub struct FocusData {
+    pub focus_tick_by_id: Arc<RwLock<HashMap<i64, u64>>>,
+    pub focus_chan: mpsc::Sender<FocusMessage>,
+}
+
+impl FocusData {
+    pub fn last_focus_tick(&self, id: i64) -> u64 {
+        *self.focus_tick_by_id
+            .read()
+            .unwrap()
+            .get(&id)
+            .unwrap_or(&0)
+    }
+
+    pub fn update_last_focus_tick(
+        &self,
+        id: i64,
+        focus_val: u64,
+    ) {
+        let mut write_lock = self.focus_tick_by_id.write().unwrap();
+        if let Some(tick) = write_lock.get_mut(&id) {
+            *tick = focus_val;
+        }
+        // else the node has since been closed before this focus event got locked in
+    }
+    
+    pub fn remove_focus_data(
+        &self,
+        id: i64
+    ) {
+        self.focus_tick_by_id.write().unwrap().remove(&id);
+    }
+    
+    /// Ensures that a given node_id is present in the ExtraProps map, this
+    /// later used to distinguish between the case where a container was
+    /// closed (it will no longer be in the map) or 
+    pub fn ensure_id(&self, id: i64) {
+        let mut write_lock = self.focus_tick_by_id.write().unwrap();
+        if write_lock.get(&id).is_none() {
+            write_lock.insert(
+                id,
+                0,
+            );
+        }
+    }
+
+    pub fn send(&self, fmsg: FocusMessage) {
+        // todo can this be removed?
+        if let FocusMessage::FocusEvent(ref fev) = fmsg { 
+            self.ensure_id(fev.node_id);
+        }
+        self.focus_chan.send(fmsg)
+            .expect("Failed to send focus event over channel");
+    }
+}
+
+pub struct FocusEvent {
+    pub node_id: i64,      // node receiving the focus
+    pub ev_focus_ctr: u64, // Counter for this specific focus event
+}
+
+pub enum FocusMessage {
+    TickUpdateInhibit,
+    TickUpdateActivate,
+    FocusEvent(FocusEvent),
+}

swayr/src/lib.rs

@@ -26,3 +26,4 @@ pub mod layout;
 pub mod shared;
 pub mod tree;
 pub mod util;
+pub mod focus;

swayr/src/tree.rs

@@ -16,6 +16,7 @@
 //! Convenience data structures built from the IPC structs.
 
 use crate::config;
+use crate::focus::FocusData;
 use crate::shared::fmt::subst_placeholders;
 use crate::shared::ipc;
 use crate::shared::ipc::NodeMethods;
@@ -23,25 +24,16 @@ use crate::util;
 use crate::util::DisplayFormat;
 use once_cell::sync::Lazy;
 use regex::Regex;
-use serde::{Deserialize, Serialize};
 use std::cell::RefCell;
 use std::cmp;
 use std::collections::HashMap;
 use std::rc::Rc;
 use swayipc as s;
 
-/// Extra properties gathered by swayrd for windows and workspaces.
-#[derive(Copy, Clone, Debug, Deserialize, Serialize)]
-pub struct ExtraProps {
-    pub last_focus_tick: u64,
-    pub last_focus_tick_for_next_prev_seq: u64,
-}
-
 pub struct Tree<'a> {
     root: &'a s::Node,
     id_node: HashMap<i64, &'a s::Node>,
     id_parent: HashMap<i64, i64>,
-    extra_props: &'a HashMap<i64, ExtraProps>,
 }
 
 #[derive(Copy, Clone, PartialEq, Eq)]
@@ -83,28 +75,23 @@ impl<'a> Tree<'a> {
         }
     }
 
-    pub fn last_focus_tick(&self, id: i64) -> u64 {
-        self.extra_props.get(&id).map_or(0, |wp| wp.last_focus_tick)
-    }
-
-    pub fn last_focus_tick_for_next_prev_seq(&self, id: i64) -> u64 {
-        self.extra_props
-            .get(&id)
-            .map_or(0, |wp| wp.last_focus_tick_for_next_prev_seq)
-    }
-
     fn sorted_nodes_of_type_1(
         &self,
         node: &'a s::Node,
         t: ipc::Type,
+        fdata: &FocusData,
     ) -> Vec<&s::Node> {
         let mut v: Vec<&s::Node> = node.nodes_of_type(t);
-        self.sort_by_urgency_and_lru_time_1(&mut v);
+        self.sort_by_urgency_and_lru_time_1(&mut v, fdata);
         v
     }
 
-    fn sorted_nodes_of_type(&self, t: ipc::Type) -> Vec<&s::Node> {
-        self.sorted_nodes_of_type_1(self.root, t)
+    fn sorted_nodes_of_type(
+        &self,
+        t: ipc::Type,
+        fdata: &FocusData,
+    ) -> Vec<&s::Node> {
+        self.sorted_nodes_of_type_1(self.root, t, fdata)
     }
 
     fn as_display_nodes(
@@ -137,16 +124,16 @@ impl<'a> Tree<'a> {
         self.as_display_nodes(&outputs, IndentLevel::Fixed(0))
     }
 
-    pub fn get_workspaces(&self) -> Vec<DisplayNode> {
-        let mut v = self.sorted_nodes_of_type(ipc::Type::Workspace);
+    pub fn get_workspaces(&self, fdata: &FocusData) -> Vec<DisplayNode> {
+        let mut v = self.sorted_nodes_of_type(ipc::Type::Workspace, fdata);
         if !v.is_empty() {
             v.rotate_left(1);
         }
         self.as_display_nodes(&v, IndentLevel::Fixed(0))
     }
 
-    pub fn get_windows(&self) -> Vec<DisplayNode> {
-        let mut v = self.sorted_nodes_of_type(ipc::Type::Window);
+    pub fn get_windows(&self, fdata: &FocusData) -> Vec<DisplayNode> {
+        let mut v = self.sorted_nodes_of_type(ipc::Type::Window, fdata);
         // Rotate, but only non-urgent windows.  Those should stay at the front
         // as they are the most likely switch candidates.
         let mut x;
@@ -169,13 +156,17 @@ impl<'a> Tree<'a> {
         self.as_display_nodes(&x, IndentLevel::Fixed(0))
     }
 
-    pub fn get_workspaces_and_windows(&self) -> Vec<DisplayNode> {
-        let workspaces = self.sorted_nodes_of_type(ipc::Type::Workspace);
+    pub fn get_workspaces_and_windows(
+        &self,
+        fdata: &FocusData,
+    ) -> Vec<DisplayNode> {
+        let workspaces = self.sorted_nodes_of_type(ipc::Type::Workspace, fdata);
         let mut first = true;
         let mut v = vec![];
         for ws in workspaces {
             v.push(ws);
-            let mut wins = self.sorted_nodes_of_type_1(ws, ipc::Type::Window);
+            let mut wins =
+                self.sorted_nodes_of_type_1(ws, ipc::Type::Window, fdata);
             if first && !wins.is_empty() {
                 wins.rotate_left(1);
                 first = false;
@@ -186,15 +177,19 @@ impl<'a> Tree<'a> {
         self.as_display_nodes(&v, IndentLevel::WorkspacesZeroWindowsOne)
     }
 
-    fn sort_by_urgency_and_lru_time_1(&self, v: &mut [&s::Node]) {
+    fn sort_by_urgency_and_lru_time_1(
+        &self,
+        v: &mut [&s::Node],
+        fdata: &FocusData,
+    ) {
         v.sort_by(|a, b| {
             if a.urgent && !b.urgent {
                 cmp::Ordering::Less
             } else if !a.urgent && b.urgent {
                 cmp::Ordering::Greater
             } else {
-                let lru_a = self.last_focus_tick(a.id);
-                let lru_b = self.last_focus_tick(b.id);
+                let lru_a = fdata.last_focus_tick(a.id);
+                let lru_b = fdata.last_focus_tick(b.id);
                 lru_a.cmp(&lru_b).reverse()
             }
         });
@@ -204,36 +199,41 @@ impl<'a> Tree<'a> {
         &self,
         n: &'a s::Node,
         v: Rc<RefCell<Vec<&'a s::Node>>>,
+        fdata: &FocusData,
     ) {
         v.borrow_mut().push(n);
 
         let mut children: Vec<&s::Node> = n.nodes.iter().collect();
         children.append(&mut n.floating_nodes.iter().collect());
-        self.sort_by_urgency_and_lru_time_1(&mut children);
+        self.sort_by_urgency_and_lru_time_1(&mut children, fdata);
 
         for c in children {
-            self.push_subtree_sorted(c, Rc::clone(&v));
+            self.push_subtree_sorted(c, Rc::clone(&v), fdata);
         }
     }
 
     pub fn get_outputs_workspaces_containers_and_windows(
         &self,
+        fdata: &FocusData,
     ) -> Vec<DisplayNode> {
-        let outputs = self.sorted_nodes_of_type(ipc::Type::Output);
+        let outputs = self.sorted_nodes_of_type(ipc::Type::Output, fdata);
         let v: Rc<RefCell<Vec<&s::Node>>> = Rc::new(RefCell::new(vec![]));
         for o in outputs {
-            self.push_subtree_sorted(o, Rc::clone(&v));
+            self.push_subtree_sorted(o, Rc::clone(&v), fdata);
         }
 
         let x = self.as_display_nodes(&*v.borrow(), IndentLevel::TreeDepth(1));
         x
     }
 
-    pub fn get_workspaces_containers_and_windows(&self) -> Vec<DisplayNode> {
-        let workspaces = self.sorted_nodes_of_type(ipc::Type::Workspace);
+    pub fn get_workspaces_containers_and_windows(
+        &self,
+        fdata: &FocusData,
+    ) -> Vec<DisplayNode> {
+        let workspaces = self.sorted_nodes_of_type(ipc::Type::Workspace, fdata);
         let v: Rc<RefCell<Vec<&s::Node>>> = Rc::new(RefCell::new(vec![]));
         for ws in workspaces {
-            self.push_subtree_sorted(ws, Rc::clone(&v));
+            self.push_subtree_sorted(ws, Rc::clone(&v), fdata);
         }
 
         let x = self.as_display_nodes(&*v.borrow(), IndentLevel::TreeDepth(2));
@@ -281,10 +281,7 @@ fn init_id_parent<'a>(
     }
 }
 
-pub fn get_tree<'a>(
-    root: &'a s::Node,
-    extra_props: &'a HashMap<i64, ExtraProps>,
-) -> Tree<'a> {
+pub fn get_tree(root: &s::Node) -> Tree {
     let mut id_node: HashMap<i64, &s::Node> = HashMap::new();
     let mut id_parent: HashMap<i64, i64> = HashMap::new();
     init_id_parent(root, None, &mut id_node, &mut id_parent);
@@ -293,7 +290,6 @@ pub fn get_tree<'a>(
         root,
         id_node,
         id_parent,
-        extra_props,
     }
 }