mpd: Implement idle events for Playing state

include/modules/mpd/state.hpp

@@ -82,6 +82,7 @@ class Idle : public State {
 class Playing : public State {
   Context* const ctx_;
   sigc::connection timer_connection_;
+  sigc::connection idle_connection_;
 
  public:
   Playing(Context* const ctx) : ctx_{ctx} {}
@@ -98,7 +99,10 @@ class Playing : public State {
   Playing(Playing const&) = delete;
   Playing& operator=(Playing const&) = delete;
 
+  void timer() noexcept;
+  void idle() noexcept;
   bool on_timer();
+  bool on_io(Glib::IOCondition const&);
 };
 
 class Paused : public State {

src/modules/mpd/state.cpp

@@ -19,13 +19,13 @@ auto format_as(enum mpd_idle val) {
 
 namespace waybar::modules::detail {
 
-#define IDLE_RUN_NOIDLE_AND_CMD(...)                                      \
+#define RUN_NOIDLE_AND_CMD(STATE, ...)                                      \
   if (idle_connection_.connected()) {                                     \
     idle_connection_.disconnect();                                        \
     auto conn = ctx_->connection().get();                                 \
     if (!mpd_run_noidle(conn)) {                                          \
       if (mpd_connection_get_error(conn) != MPD_ERROR_SUCCESS) {          \
-        spdlog::error("mpd: Idle: failed to unregister for IDLE events"); \
+        spdlog::error("mpd: STATE: failed to unregister for IDLE events"); \
         ctx_->checkErrors(conn);                                          \
       }                                                                   \
     }                                                                     \
@@ -33,24 +33,23 @@ namespace waybar::modules::detail {
   }
 
 void Idle::play() {
-  IDLE_RUN_NOIDLE_AND_CMD(mpd_run_play(conn));
+  RUN_NOIDLE_AND_CMD(Idle, mpd_run_play(conn));
 
   ctx_->setState(std::make_unique<Playing>(ctx_));
 }
 
 void Idle::pause() {
-  IDLE_RUN_NOIDLE_AND_CMD(mpd_run_pause(conn, true));
+  RUN_NOIDLE_AND_CMD(Idle, mpd_run_pause(conn, true));
 
   ctx_->setState(std::make_unique<Paused>(ctx_));
 }
 
 void Idle::stop() {
-  IDLE_RUN_NOIDLE_AND_CMD(mpd_run_stop(conn));
+  RUN_NOIDLE_AND_CMD(Idle, mpd_run_stop(conn));
 
   ctx_->setState(std::make_unique<Stopped>(ctx_));
 }
 
-#undef IDLE_RUN_NOIDLE_AND_CMD
 
 void Idle::update() noexcept {
   // This is intentionally blank.
@@ -118,18 +117,50 @@ bool Idle::on_io(Glib::IOCondition const&) {
 }
 
 void Playing::entry() noexcept {
-  sigc::slot<bool> timer_slot = sigc::mem_fun(*this, &Playing::on_timer);
+  timer();
-  timer_connection_ = Glib::signal_timeout().connect_seconds(timer_slot, 1);
+  idle();
   spdlog::debug("mpd: Playing: enabled 1 second periodic timer.");
 }
 
 void Playing::exit() noexcept {
+  if (idle_connection_.connected()) {
+    idle_connection_.disconnect();
+    spdlog::debug("mpd: Playing: unwatching FD");
+  }
+
   if (timer_connection_.connected()) {
     timer_connection_.disconnect();
     spdlog::debug("mpd: Playing: disabled 1 second periodic timer.");
   }
 }
 
+void Playing::timer() noexcept {
+  if (timer_connection_.connected()) {
+    timer_connection_.disconnect();
+  }
+
+  sigc::slot<bool> timer_slot = sigc::mem_fun(*this, &Playing::on_timer);
+  timer_connection_ = Glib::signal_timeout().connect_seconds(timer_slot, 1);
+}
+
+
+void Playing::idle() noexcept {
+  auto conn = ctx_->connection().get();
+  assert(conn != nullptr);
+
+  if (!mpd_send_idle_mask(
+          conn, static_cast<mpd_idle>(MPD_IDLE_PLAYER | MPD_IDLE_OPTIONS | MPD_IDLE_QUEUE))) {
+    ctx_->checkErrors(conn);
+    spdlog::error("mpd: Playing: failed to register for IDLE events");
+  } else if (!idle_connection_.connected()) {
+    spdlog::trace("mpd: Playing: watching FD");
+    sigc::slot<bool, Glib::IOCondition const&> idle_slot = sigc::mem_fun(*this, &Playing::on_io);
+    idle_connection_ =
+        Glib::signal_io().connect(idle_slot, mpd_connection_get_fd(conn),
+                                  Glib::IO_IN | Glib::IO_PRI | Glib::IO_ERR | Glib::IO_HUP);
+  }
+}
+
 bool Playing::on_timer() {
   // Attempt to connect with MPD.
   try {
@@ -141,6 +172,8 @@ bool Playing::on_timer() {
       return false;
     }
 
+    RUN_NOIDLE_AND_CMD(Playing);
+
     ctx_->fetchState();
 
     if (!ctx_->is_playing()) {
@@ -154,6 +187,50 @@ bool Playing::on_timer() {
 
     ctx_->queryMPD();
     ctx_->emit();
+
+    idle();
+  } catch (std::exception const& e) {
+    spdlog::warn("mpd: Playing: error: {}", e.what());
+    ctx_->setState(std::make_unique<Disconnected>(ctx_));
+    return false;
+  }
+
+  return true;
+}
+
+bool Playing::on_io(Glib::IOCondition const&) {
+  auto conn = ctx_->connection().get();
+
+  // callback should do this:
+  enum mpd_idle events = mpd_recv_idle(conn, /* ignore_timeout?= */ false);
+  spdlog::debug("mpd: Playing: recv_idle events -> {}", events);
+
+  mpd_response_finish(conn);
+  try {
+    ctx_->checkErrors(conn);
+
+    ctx_->fetchState();
+
+    if (!ctx_->is_playing()) {
+      if (ctx_->is_paused()) {
+        ctx_->setState(std::make_unique<Paused>(ctx_));
+      } else {
+        ctx_->setState(std::make_unique<Stopped>(ctx_));
+      }
+      return false;
+    }
+
+    ctx_->queryMPD();
+    ctx_->emit();
+
+    if (!mpd_send_idle_mask(
+            conn, static_cast<mpd_idle>(MPD_IDLE_PLAYER | MPD_IDLE_OPTIONS | MPD_IDLE_QUEUE))) {
+      ctx_->checkErrors(conn);
+      spdlog::error("mpd: Playing: failed to register for IDLE events");
+    }
+
+    // Defer the next timer
+    timer();
   } catch (std::exception const& e) {
     spdlog::warn("mpd: Playing: error: {}", e.what());
     ctx_->setState(std::make_unique<Disconnected>(ctx_));
@@ -164,21 +241,25 @@ bool Playing::on_timer() {
 }
 
 void Playing::stop() {
+  RUN_NOIDLE_AND_CMD(Playing,
     if (timer_connection_.connected()) {
       timer_connection_.disconnect();
 
       mpd_run_stop(ctx_->connection().get());
     }
+  );
 
   ctx_->setState(std::make_unique<Stopped>(ctx_));
 }
 
 void Playing::pause() {
+  RUN_NOIDLE_AND_CMD(Playing,
     if (timer_connection_.connected()) {
       timer_connection_.disconnect();
 
       mpd_run_pause(ctx_->connection().get(), true);
     }
+  );
 
   ctx_->setState(std::make_unique<Paused>(ctx_));
 }
@@ -387,4 +468,5 @@ bool Disconnected::on_timer() {
 
 void Disconnected::update() noexcept { ctx_->do_update(); }
 
+#undef RUN_NOIDLE_AND_CMD
 }  // namespace waybar::modules::detail