equivalent exchange of boilerplate

src/mpris/player.rs

@@ -219,17 +219,24 @@ impl Player {
 
         Ok(())
     }
+
+    fn playbin(&self) -> zbus::fdo::Result<crate::Playbin> {
+        match self.playbin.upgrade() {
+            None => Err(zbus::fdo::Error::Failed("playbin was discarded".into())),
+            Some(playbin) => Ok(playbin),
+        }
+    }
 }
 
 #[zbus::interface(name = "org.mpris.MediaPlayer2.Player")]
 impl Player {
-    fn next(&self) {
+    fn next(&self) -> zbus::fdo::Result<()> {
         // If CanGoNext is false, attempting to call this method should have no effect.
-        if !self.can_go_next() {
+        if !self.can_go_next()? {
-            return;
+            return Ok(());
         }
 
-        let playbin = self.playbin.upgrade().unwrap();
+        let playbin = self.playbin()?;
         if playbin.play_queue_position() + 1 > playbin.play_queue_length() {
             // If there is no next track (and endless playback and track repeat are both off), stop playback.
             // (interpret this as something else than what Stop does)
@@ -237,14 +244,16 @@ impl Player {
         } else {
             playbin.go_to_next_track();
         }
+
+        Ok(())
     }
 
-    fn previous(&self) {
+    fn previous(&self) -> zbus::fdo::Result<()> {
-        let playbin = self.playbin.upgrade().unwrap();
+        let playbin = self.playbin()?;
 
         // If CanGoPrevious is false, attempting to call this method should have no effect.
-        if !self.can_go_previous() {
+        if !self.can_go_previous()? {
-            return;
+            return Ok(());
         }
 
         if playbin.play_queue_position() == 0 {
@@ -254,74 +263,79 @@ impl Player {
         } else {
             playbin.go_to_prev_track();
         }
+
+        Ok(())
     }
 
-    fn pause(&self) {
+    fn pause(&self) -> zbus::fdo::Result<()> {
-        let playbin = self.playbin.upgrade().unwrap();
+        let playbin = self.playbin()?;
 
         // If CanPause is false, attempting to call this method should have no effect.
         if !self.can_pause() {
-            return;
+            return Ok(());
         }
 
         // If playback is already paused, this has no effect.
         if playbin.state() != crate::playbin::State::Playing {
-            return;
+            return Ok(());
         }
 
-        self.playbin.upgrade().unwrap().pause();
+        playbin.pause();
+        Ok(())
     }
 
-    fn play_pause(&self) {
+    fn play_pause(&self) -> zbus::fdo::Result<()> {
         // don't think this is exactly according to spec but it looks more reasonable to me
-        if self.playbin.upgrade().unwrap().state() == crate::playbin::State::Paused {
+        if self.playbin()?.state() == crate::playbin::State::Paused {
-            self.play();
+            self.play()
         } else {
-            self.pause();
+            self.pause()
         }
     }
 
-    fn stop(&self) {
+    fn stop(&self) -> zbus::fdo::Result<()> {
-        let playbin = self.playbin.upgrade().unwrap();
+        let playbin = self.playbin()?;
 
         // If playback is already stopped, this has no effect.
         if playbin.state() != crate::playbin::State::Playing {
-            return;
+            return Ok(());
         }
 
         // Calling Play after this should cause playback to start again from the beginning of the track.
         playbin.pause();
         playbin.seek(0.0);
+        Ok(())
     }
 
-    fn play(&self) {
+    fn play(&self) -> zbus::fdo::Result<()> {
-        let playbin = self.playbin.upgrade().unwrap();
+        let playbin = self.playbin()?;
 
         // If CanPlay is false, attempting to call this method should have no effect.
-        if !self.can_play() {
+        if !self.can_play()? {
-            return;
+            return Ok(());
         }
 
         // If already playing, this has no effect.
         if playbin.state() == crate::playbin::State::Playing {
-            return;
+            return Ok(());
         }
 
         // If there is no track to play, this has no effect.
         if playbin.play_queue_length() == 0 {
-            return;
+            return Ok(());
         }
 
         playbin.play();
+        Ok(())
     }
 
-    fn seek(&self, offset: i64) {
+    fn seek(&self, offset: i64) -> zbus::fdo::Result<()> {
         // If the CanSeek property is false, this has no effect.
         if !self.can_seek() {
-            return;
+            return Ok(());
         }
 
-        let playbin = self.playbin.upgrade().unwrap();
+        let playbin = self.playbin()?;
         // Seeks forward in the current track by the specified number of microseconds.
         let mut new_position = (playbin.position() * MICROSECONDS) as i64 + offset;
 
@@ -336,30 +350,32 @@ impl Player {
         }
 
         playbin.seek(new_position as f64 / MICROSECONDS);
+        Ok(())
     }
 
-    fn set_position(&self, track_id: ObjectPath<'_>, position: i64) {
+    fn set_position(&self, track_id: ObjectPath<'_>, position: i64) -> zbus::fdo::Result<()> {
-        let playbin = self.playbin.upgrade().unwrap();
+        let playbin = self.playbin()?;
 
         // If the Position argument is less than 0, do nothing.
         if position < 0 {
-            return;
+            return Ok(());
         }
         // If the Position argument is greater than the track length, do nothing.
         if position > (playbin.duration() * MICROSECONDS) as i64 {
-            return;
+            return Ok(());
         }
         // If the CanSeek property is false, this has no effect.
         if !self.can_seek() {
-            return;
+            return Ok(());
         }
         // check if it's stale
         if self.metadata.track_id.as_deref() != Some(&track_id) {
             // TODO: warn of stale seek
-            return;
+            return Ok(());
         }
 
         playbin.seek(position as f64 / MICROSECONDS);
+        Ok(())
     }
 
     fn open_uri(&self, _s: &str) -> zbus::fdo::Result<()> {
@@ -370,47 +386,50 @@ impl Player {
     async fn seeked(signal_emitter: &SignalEmitter<'_>, position: i64) -> zbus::Result<()>;
 
     #[zbus(property)]
-    fn playback_status(&self) -> String {
+    fn playback_status(&self) -> zbus::fdo::Result<&str> {
-        match self.playbin.upgrade().unwrap().state() {
+        match self.playbin()?.state() {
-            crate::playbin::State::Stopped => "Stopped".into(),
+            crate::playbin::State::Stopped => Ok("Stopped"),
-            crate::playbin::State::Playing => "Playing".into(),
+            crate::playbin::State::Playing => Ok("Playing"),
-            crate::playbin::State::Paused => "Paused".into(),
+            crate::playbin::State::Paused => Ok("Paused"),
         }
     }
 
     #[zbus(property)]
-    fn loop_status(&self) -> String {
+    fn loop_status(&self) -> zbus::fdo::Result<String> {
-        "None".into() // TODO
+        Ok("None".into()) // TODO
     }
 
     #[zbus(property)]
     fn set_loop_status(&self, _loop_status: &str) -> zbus::Result<()> {
-        Err(zbus::Error::Unsupported) // TODO
+        Err(zbus::fdo::Error::NotSupported("setting LoopStatus".into()).into()) // TODO
     }
 
     #[zbus(property)]
-    fn rate(&self) -> f64 {
+    fn rate(&self) -> zbus::fdo::Result<f64> {
-        1.0
+        Ok(1.0)
     }
 
     #[zbus(property)]
-    fn set_rate(&self, rate: f64) {
+    fn set_rate(&self, rate: f64) -> zbus::Result<()> {
         // A value of 0.0 should not be set by the client. If it is, the media player should act as though Pause was called.
         if rate == 0.0 {
-            self.pause();
+            self.pause()?;
         }
 
         // just ignore anything else
+        Ok(())
     }
 
     #[zbus(property)]
-    fn shuffle(&self) -> bool {
+    // FIXME: zbus bug (?): this getter can't be infallible
-        false
+    fn shuffle(&self) -> zbus::fdo::Result<bool> {
+        Ok(false)
     }
 
     #[zbus(property)]
+    // FIXME: zbus bug (?): this setter can't return zbus::fdo::Result
     fn set_shuffle(&self, _shuffle: bool) -> zbus::Result<()> {
-        Err(zbus::Error::Unsupported)
+        Err(zbus::fdo::Error::NotSupported("setting Shuffle".into()).into())
     }
 
     #[zbus(property)]
@@ -419,24 +438,25 @@ impl Player {
     }
 
     #[zbus(property)]
-    fn volume(&self) -> f64 {
+    fn volume(&self) -> zbus::fdo::Result<f64> {
-        self.playbin.upgrade().unwrap().volume() as f64 / 100.0
+        Ok(self.playbin()?.volume() as f64 / 100.0)
     }
 
     #[zbus(property)]
-    fn set_volume(&mut self, mut volume: f64) {
+    fn set_volume(&mut self, mut volume: f64) -> zbus::fdo::Result<()> {
         // When setting, if a negative value is passed, the volume should be set to 0.0.
         if volume < 0.0 {
             volume = 0.0;
         }
-        let playbin = self.playbin.upgrade().unwrap();
+        let playbin = self.playbin()?;
         // FIXME: check if this is set by the notify callback: self.volume = volume;
         playbin.set_volume((volume * 100.0) as i32);
+        Ok(())
     }
 
     #[zbus(property(emits_changed_signal = "false"))]
-    fn position(&self) -> i64 {
+    fn position(&self) -> zbus::fdo::Result<i64> {
-        (self.playbin.upgrade().unwrap().position() * MICROSECONDS) as i64
+        Ok((self.playbin()?.position() * MICROSECONDS) as i64)
     }
 
     #[zbus(property)]
@@ -450,21 +470,21 @@ impl Player {
     }
 
     #[zbus(property)]
-    fn can_go_next(&self) -> bool {
+    fn can_go_next(&self) -> zbus::fdo::Result<bool> {
         // same as can_play
-        self.playbin.upgrade().unwrap().play_queue_length() > 0
+        Ok(self.playbin()?.play_queue_length() > 0)
     }
 
     #[zbus(property)]
-    fn can_go_previous(&self) -> bool {
+    fn can_go_previous(&self) -> zbus::fdo::Result<bool> {
         // same as can_play
-        self.playbin.upgrade().unwrap().play_queue_length() > 0
+        Ok(self.playbin()?.play_queue_length() > 0)
     }
 
     #[zbus(property)]
-    fn can_play(&self) -> bool {
+    fn can_play(&self) -> zbus::fdo::Result<bool> {
         // it only makes sense to disallow "play" when the play queue is empty
-        self.playbin.upgrade().unwrap().play_queue_length() > 0
+        Ok(self.playbin()?.play_queue_length() > 0)
     }
 
     #[zbus(property)]