add initial MPRIS support using zbus

- following the spec at https://specifications.freedesktop.org/mpris-spec/latest/

- some properties/commands are not fully supported, yet

Cargo.lock

@@ -1911,8 +1911,11 @@ dependencies = [
  "sha1",
  "sysinfo",
  "thiserror",
+ "time",
  "tokio",
  "url",
+ "zbus",
+ "zvariant",
 ]
 
 [[package]]

Cargo.toml

@@ -64,7 +64,10 @@ sha1 = "0.10"
 sysinfo = { version = "0.31.3", default-features = false, features = ["system"] }
 thiserror = "1.0"
 tokio = { version = "1.40", features = ["rt", "macros", "signal", "sync", "parking_lot", "process"] }
+time = { version = "0.3", features = ["formatting"] }
 url = "2.2"
+zbus = { version = "4", default-features = false, features = ["tokio"], optional = true }
+zvariant = { version = "4", default-features = false, optional = true }
 
 [features]
 alsa-backend = ["librespot-playback/alsa-backend"]
@@ -82,7 +85,9 @@ with-libmdns = ["librespot-discovery/with-libmdns"]
 
 passthrough-decoder = ["librespot-playback/passthrough-decoder"]
 
-default = ["rodio-backend", "with-libmdns"]
+with-mpris = ["dep:zbus", "dep:zvariant"]
+
+default = ["rodio-backend", "with-libmdns", "with-mpris"]
 
 [package.metadata.deb]
 maintainer = "librespot-org"

src/main.rs

@@ -40,6 +40,11 @@ use librespot::playback::mixer::alsamixer::AlsaMixer;
 mod player_event_handler;
 use player_event_handler::{run_program_on_sink_events, EventHandler};
 
+#[cfg(feature = "with-mpris")]
+mod mpris_event_handler;
+#[cfg(feature = "with-mpris")]
+use mpris_event_handler::MprisEventHandler;
+
 fn device_id(name: &str) -> String {
     HEXLOWER.encode(&Sha1::digest(name.as_bytes()))
 }
@@ -1937,6 +1942,14 @@ async fn main() {
         }
     }
 
+    #[cfg(feature = "with-mpris")]
+    let mpris = MprisEventHandler::spawn(player.clone())
+        .await
+        .unwrap_or_else(|e| {
+            error!("could not initialize MPRIS: {}", e);
+            exit(1);
+        });
+
     loop {
         tokio::select! {
             credentials = async {
@@ -1990,6 +2003,10 @@ async fn main() {
                         exit(1);
                     }
                 };
+
+                #[cfg(feature = "with-mpris")]
+                mpris.set_spirc(spirc_.clone());
+
                 spirc = Some(spirc_);
                 spirc_task = Some(Box::pin(spirc_task_));
 
@@ -2035,6 +2052,9 @@ async fn main() {
 
     let mut shutdown_tasks = tokio::task::JoinSet::new();
 
+    #[cfg(feature = "with-mpris")]
+    shutdown_tasks.spawn(mpris.quit_and_join());
+
     // Shutdown spirc if necessary
     if let Some(spirc) = spirc {
         if let Err(e) = spirc.shutdown() {