Use a VecDeque for events so that we're not missing some

swayrbar/src/bar.rs

@@ -20,6 +20,7 @@ use crate::module;
 use crate::module::{BarModuleFn, NameAndInstance};
 use env_logger::Env;
 use serde_json;
+use std::collections::VecDeque;
 use std::io;
 use std::process as p;
 use std::sync::Condvar;
@@ -30,6 +31,7 @@ use swaybar_types as sbt;
 use swayipc as si;
 
 type NameInstanceAndReason = (String, String, String);
+type Trigger = Arc<(Mutex<VecDeque<NameInstanceAndReason>>, Condvar)>;
 
 pub fn start() {
     env_logger::Builder::from_env(Env::default().default_filter_or("warn"))
@@ -39,10 +41,8 @@ pub fn start() {
     let refresh_interval = config.refresh_interval;
     let mods: Arc<Vec<Box<dyn BarModuleFn>>> = Arc::new(create_modules(config));
     let mods_for_input = mods.clone();
-    let trigger: Arc<(Mutex<NameInstanceAndReason>, Condvar)> = Arc::new((
-        Mutex::new((String::new(), String::new(), String::new())),
-        Condvar::new(),
-    ));
+    let trigger: Trigger =
+        Arc::new((Mutex::new(VecDeque::new()), Condvar::new()));
 
     let trigger_for_input = trigger.clone();
     thread::spawn(move || handle_input(mods_for_input, trigger_for_input));
@@ -83,10 +83,7 @@ fn create_modules(config: config::Config) -> Vec<Box<dyn BarModuleFn>> {
     mods
 }
 
-fn handle_input(
-    mods: Arc<Vec<Box<dyn BarModuleFn>>>,
-    trigger: Arc<(Mutex<NameInstanceAndReason>, Condvar)>,
-) {
+fn handle_input(mods: Arc<Vec<Box<dyn BarModuleFn>>>, trigger: Trigger) {
     let mut sb = String::new();
     io::stdin()
         .read_line(&mut sb)
@@ -120,10 +117,8 @@ fn handle_input(
         log::debug!("Received click: {:?}", click);
         if let Some((name, instance)) = handle_click(click, mods.clone()) {
             let (mtx, cvar) = &*trigger;
-            let mut name_inst_reason = mtx.lock().unwrap();
-            name_inst_reason.0 = name;
-            name_inst_reason.1 = instance;
-            name_inst_reason.2 = String::from("click event");
+            let mut queue = mtx.lock().unwrap();
+            queue.push_back((name, instance, String::from("click event")));
             cvar.notify_one();
         }
     }
@@ -146,6 +141,9 @@ fn handle_click(
                 let cfg = m.get_config();
                 // No refresh for click events for window modules because the
                 // refresh will be triggered by a sway event anyhow.
+                //
+                // TODO: That's too much coupling.  The bar module shouldn't do
+                // specific stuff for certain modules.
                 if cfg.name == module::window::NAME {
                     return None;
                 }
@@ -184,10 +182,7 @@ fn sway_subscribe() -> si::Fallible<si::EventStream> {
     ])
 }
 
-fn handle_sway_events(
-    window_mods: Vec<NameAndInstance>,
-    trigger: Arc<(Mutex<NameInstanceAndReason>, Condvar)>,
-) {
+fn handle_sway_events(window_mods: Vec<NameAndInstance>, trigger: Trigger) {
     let mut resets = 0;
     let max_resets = 10;
 
@@ -216,12 +211,12 @@ fn handle_sway_events(
                                 );
                                 for m in &window_mods {
                                     let (mtx, cvar) = &*trigger;
-                                    let mut name_inst_reason =
-                                        mtx.lock().unwrap();
-                                    name_inst_reason.0 = m.0.to_owned();
-                                    name_inst_reason.1 = m.1.to_owned();
-                                    name_inst_reason.2 =
-                                        String::from("sway event");
+                                    let mut queue = mtx.lock().unwrap();
+                                    queue.push_back((
+                                        m.0.to_owned(),
+                                        m.1.to_owned(),
+                                        String::from("sway event"),
+                                    ));
                                     cvar.notify_one();
                                 }
                             }
@@ -248,31 +243,31 @@ fn handle_sway_events(
     }
 }
 
+fn generate_status_1(
+    mods: &[Box<dyn BarModuleFn>],
+    name_and_instance: &Option<NameAndInstance>,
+) {
+    let mut blocks = vec![];
+    for m in mods {
+        blocks.push(m.build(name_and_instance));
+    }
+    let json = serde_json::to_string_pretty(&blocks)
+        .unwrap_or_else(|_| "".to_string());
+    println!("{},", json);
+}
+
 fn generate_status(
     mods: &[Box<dyn BarModuleFn>],
-    trigger: Arc<(Mutex<NameInstanceAndReason>, Condvar)>,
+    trigger: Trigger,
     refresh_interval: u64,
 ) {
     println!("{{\"version\": 1, \"click_events\": true}}");
     // status_command should output an infinite array meaning we emit an
     // opening [ and never the closing bracket.
     println!("[");
-
-    let mut name_inst_reason: Option<NameInstanceAndReason> = None;
+    generate_status_1(mods, &None);
 
     loop {
-        let mut blocks = vec![];
-        let name_and_instance = &name_inst_reason.map(|x| (x.0, x.1));
-        for m in mods {
-            blocks.push(m.build(name_and_instance));
-        }
-        let json = serde_json::to_string_pretty(&blocks)
-            .unwrap_or_else(|_| "".to_string());
-        println!("{},", json);
-
-        // FIXME: We sometimes miss click or sway events, most probably because
-        // the corresponding notify_one() is executed when we are not waiting
-        // here.
         let (lock, cvar) = &*trigger;
         let result = cvar
             .wait_timeout(
@@ -280,16 +275,19 @@ fn generate_status(
                 Duration::from_millis(refresh_interval),
             )
             .unwrap();
-        if result.1.timed_out() {
-            name_inst_reason = None;
+        let mut queue = result.0;
+        if queue.is_empty() {
+            generate_status_1(mods, &None);
         } else {
-            name_inst_reason = Some((*result.0).clone());
             log::debug!(
-                "Status writing thread woke up early by {} for {}/{}.",
-                &result.0 .2,
-                &result.0 .0,
-                &result.0 .1
+                "Status writing thread woke up early events:\n{:?}",
+                queue
             );
+            while let Some(name_inst_reason) = queue.pop_front() {
+                let name_and_instance =
+                    Some(name_inst_reason).map(|x| (x.0, x.1));
+                generate_status_1(mods, &name_and_instance);
+            }
         }
     }
 }