adds try_seek for sink and all sources

examples/seek_mp3.rs

@@ -6,13 +6,13 @@ fn main() {
     let sink = rodio::Sink::try_new(&handle).unwrap();
 
     let file = std::fs::File::open("examples/music.mp3").unwrap();
-    sink.append_seekable(rodio::Decoder::new(BufReader::new(file)).unwrap());
+    sink.append(rodio::Decoder::new(BufReader::new(file)).unwrap());
 
     std::thread::sleep(std::time::Duration::from_secs(2));
-    sink.seek(Duration::from_secs(0));
+    sink.try_seek(Duration::from_secs(0)).unwrap();
 
     std::thread::sleep(std::time::Duration::from_secs(2));
-    sink.seek(Duration::from_secs(4));
+    sink.try_seek(Duration::from_secs(4)).unwrap();
 
     sink.sleep_until_end();
 }

src/conversions/channels.rs

@@ -44,6 +44,12 @@ where
     pub fn into_inner(self) -> I {
         self.input
     }
+
+    /// Get mutable access to the iterator
+    #[inline]
+    pub fn inner_mut(&mut self) -> &mut I {
+        &mut self.input
+    }
 }
 
 impl<I> Iterator for ChannelCountConverter<I>

src/conversions/sample.rs

@@ -23,6 +23,12 @@ impl<I, O> DataConverter<I, O> {
     pub fn into_inner(self) -> I {
         self.input
     }
+
+    /// get mutable access to the iterator
+    #[inline]
+    pub fn inner_mut(&mut self) -> &mut I {
+        &mut self.input
+    }
 }
 
 impl<I, O> Iterator for DataConverter<I, O>

src/conversions/sample_rate.rs

@@ -102,6 +102,12 @@ where
         self.input
     }
 
+    /// get mutable access to the iterator
+    #[inline]
+    pub fn inner_mut(&mut self) -> &mut I {
+        &mut self.input
+    }
+
     fn next_input_frame(&mut self) {
         self.current_frame_pos_in_chunk += 1;
 

src/sink.rs

@@ -3,10 +3,11 @@ use std::sync::{Arc, Mutex};
 use std::time::Duration;
 
 #[cfg(feature = "crossbeam-channel")]
-use crossbeam_channel::Receiver;
+use crossbeam_channel::{Receiver, Sender};
 #[cfg(not(feature = "crossbeam-channel"))]
-use std::sync::mpsc::Receiver;
+use std::sync::mpsc::{Receiver, Sender};
 
+use crate::source::SeekNotSupported;
 use crate::stream::{OutputStreamHandle, PlayError};
 use crate::{queue, source::Done, Sample, Source};
 use cpal::FromSample;
@@ -25,13 +26,44 @@ pub struct Sink {
     detached: bool,
 }
 
+struct SeekOrder {
+    pos: Duration,
+    feedback: Sender<Result<(), SeekNotSupported>>,
+}
+
+impl SeekOrder {
+    fn new(pos: Duration) -> (Self, Receiver<Result<(), SeekNotSupported>>) {
+        #[cfg(not(feature = "crossbeam-channel"))]
+        let (tx, rx) = {
+            use std::sync::mpsc;
+            mpsc::channel()
+        };
+
+        #[cfg(feature = "crossbeam-channel")]
+        let (tx, rx) = {
+            use crossbeam_channel::bounded;
+            bounded(1)
+        };
+        (Self { pos, feedback: tx }, rx)
+    }
+
+    fn attempt<S>(self, maybe_seekable: &mut S)
+    where
+        S: Source,
+        S::Item: Sample + Send,
+    {
+        let res = maybe_seekable.try_seek(self.pos);
+        let _ignore_reciever_dropped = self.feedback.send(res);
+    }
+}
+
 struct Controls {
     pause: AtomicBool,
     volume: Mutex<f32>,
     stopped: AtomicBool,
     speed: Mutex<f32>,
     to_clear: Mutex<u32>,
-    seek: Mutex<Option<Duration>>,
+    seek: Mutex<Option<SeekOrder>>,
 }
 
 impl Sink {
@@ -109,61 +141,8 @@ impl Sink {
                 amp.inner_mut()
                     .inner_mut()
                     .set_factor(*controls.speed.lock().unwrap());
-                start_played.store(true, Ordering::SeqCst);
-            })
-            .convert_samples();
-        self.sound_count.fetch_add(1, Ordering::Relaxed);
-        let source = Done::new(source, self.sound_count.clone());
-        *self.sleep_until_end.lock().unwrap() = Some(self.queue_tx.append_with_signal(source));
-    }
-
-    /// Appends a sound to the queue of sounds to play.
-    #[inline]
-    pub fn append_seekable<S>(&self, source: S)
-    where
-        S: Source + Send + 'static,
-        f32: FromSample<S::Item>,
-        S::Item: Sample + Send,
-    {
-        // Wait for queue to flush then resume stopped playback
-        if self.controls.stopped.load(Ordering::SeqCst) {
-            if self.sound_count.load(Ordering::SeqCst) > 0 {
-                self.sleep_until_end();
-            }
-            self.controls.stopped.store(false, Ordering::SeqCst);
-        }
-
-        let controls = self.controls.clone();
-
-        let start_played = AtomicBool::new(false);
-
-        let source = source
-            .speed(1.0)
-            .pausable(false)
-            .amplify(1.0)
-            .skippable()
-            .stoppable()
-            .periodic_access(Duration::from_millis(5), move |src| {
-                if controls.stopped.load(Ordering::SeqCst) {
-                    src.stop();
-                }
-                {
-                    let mut to_clear = controls.to_clear.lock().unwrap();
-                    if *to_clear > 0 {
-                        let _ = src.inner_mut().skip();
-                        *to_clear -= 1;
-                    }
-                }
-                let amp = src.inner_mut().inner_mut();
-                amp.set_factor(*controls.volume.lock().unwrap());
-                amp.inner_mut()
-                    .set_paused(controls.pause.load(Ordering::SeqCst));
-                amp.inner_mut()
-                    .inner_mut()
-                    .set_factor(*controls.speed.lock().unwrap());
-                let seekable = amp.inner_mut().inner_mut().inner_mut();
-                if let Some(pos) = controls.seek.lock().unwrap().take() {
-                    seekable.try_seek(pos).unwrap();
+                if let Some(seek) = controls.seek.lock().unwrap().take() {
+                    seek.attempt(amp)
                 }
                 start_played.store(true, Ordering::SeqCst);
             })
@@ -219,9 +198,18 @@ impl Sink {
 
     /// Set position
     ///
-    /// No effect if source does not implement `SourceExt`
-    pub fn seek(&self, pos: Duration) {
-        *self.controls.seek.lock().unwrap() = Some(pos);
+    /// Try to seek to a pos, returns [`SeekNotSupported`] if seeking is not
+    /// supported by the current source.
+    pub fn try_seek(&self, pos: Duration) -> Result<(), SeekNotSupported> {
+        let (order, feedback) = SeekOrder::new(pos);
+        *self.controls.seek.lock().unwrap() = Some(order);
+        match feedback.recv() {
+            Ok(seek_res) => seek_res,
+            // The feedback channel closed. Probably another seekorder was set 
+            // invalidating this one and closing the feedback channel
+            // ... or the audio thread panicked. 
+            Err(_) => Ok(()),
+        }
     }
 
     /// Pauses playback of this sink.

src/source/amplify.rs

@@ -2,6 +2,8 @@ use std::time::Duration;
 
 use crate::{Sample, Source};
 
+use super::SeekNotSupported;
+
 /// Internal function that builds a `Amplify` object.
 pub fn amplify<I>(input: I, factor: f32) -> Amplify<I>
 where
@@ -93,4 +95,9 @@ where
     fn total_duration(&self) -> Option<Duration> {
         self.input.total_duration()
     }
+
+    #[inline]
+    fn try_seek(&mut self, pos: Duration) -> Result<(), SeekNotSupported> {
+        self.input.try_seek(pos)
+    }
 }

src/source/blt.rs

@@ -3,6 +3,8 @@ use std::time::Duration;
 
 use crate::Source;
 
+use super::SeekNotSupported;
+
 // Implemented following http://www.musicdsp.org/files/Audio-EQ-Cookbook.txt
 
 /// Internal function that builds a `BltFilter` object.
@@ -147,6 +149,11 @@ where
     fn total_duration(&self) -> Option<Duration> {
         self.input.total_duration()
     }
+
+    #[inline]
+    fn try_seek(&mut self, pos: Duration) -> Result<(), SeekNotSupported> {
+        self.input.try_seek(pos)
+    }
 }
 
 #[derive(Clone, Debug)]

src/source/buffered.rs

@@ -5,6 +5,8 @@ use std::time::Duration;
 
 use crate::{Sample, Source};
 
+use super::SeekNotSupported;
+
 /// Internal function that builds a `Buffered` object.
 #[inline]
 pub fn buffered<I>(input: I) -> Buffered<I>
@@ -239,6 +241,11 @@ where
     fn total_duration(&self) -> Option<Duration> {
         self.total_duration
     }
+
+    #[inline]
+    fn try_seek(&mut self, _: Duration) -> Result<(), SeekNotSupported> {
+        Err(SeekNotSupported)
+    }
 }
 
 impl<I> Clone for Buffered<I>

src/source/channel_volume.rs

@@ -2,6 +2,8 @@ use std::time::Duration;
 
 use crate::{Sample, Source};
 
+use super::SeekNotSupported;
+
 /// Combines channels in input into a single mono source, then plays that mono sound
 /// to each channel at the volume given for that channel.
 #[derive(Clone, Debug)]
@@ -138,4 +140,9 @@ where
     fn total_duration(&self) -> Option<Duration> {
         self.input.total_duration()
     }
+
+    #[inline]
+    fn try_seek(&mut self, pos: Duration) -> Result<(), SeekNotSupported> {
+        self.input.try_seek(pos)
+    }
 }

src/source/delay.rs

@@ -2,6 +2,8 @@ use std::time::Duration;
 
 use crate::{Sample, Source};
 
+use super::SeekNotSupported;
+
 /// Internal function that builds a `Delay` object.
 pub fn delay<I>(input: I, duration: Duration) -> Delay<I>
 where
@@ -105,4 +107,10 @@ where
             .total_duration()
             .map(|val| val + self.requested_duration)
     }
+
+    #[inline]
+    fn try_seek(&mut self, pos: Duration) -> Result<(), SeekNotSupported> {
+        let pos_without_delay = pos.saturating_sub(self.requested_duration);
+        self.input.try_seek(pos_without_delay)
+    }
 }

src/source/done.rs

@@ -4,6 +4,8 @@ use std::time::Duration;
 
 use crate::{Sample, Source};
 
+use super::SeekNotSupported;
+
 /// When the inner source is empty this decrements an `AtomicUsize`.
 #[derive(Debug, Clone)]
 pub struct Done<I> {
@@ -87,4 +89,9 @@ where
     fn total_duration(&self) -> Option<Duration> {
         self.input.total_duration()
     }
+
+    #[inline]
+    fn try_seek(&mut self, pos: Duration) -> Result<(), SeekNotSupported> {
+        self.input.try_seek(pos)
+    }
 }

src/source/empty.rs

@@ -3,6 +3,8 @@ use std::time::Duration;
 
 use crate::{Sample, Source};
 
+use super::SeekNotSupported;
+
 /// An empty source.
 #[derive(Debug, Copy, Clone)]
 pub struct Empty<S>(PhantomData<S>);
@@ -53,4 +55,9 @@ where
     fn total_duration(&self) -> Option<Duration> {
         Some(Duration::new(0, 0))
     }
+
+    #[inline]
+    fn try_seek(&mut self, _: Duration) -> Result<(), SeekNotSupported> {
+        Err(SeekNotSupported)
+    }
 }

src/source/empty_callback.rs

@@ -3,6 +3,8 @@ use std::time::Duration;
 
 use crate::{Sample, Source};
 
+use super::SeekNotSupported;
+
 /// An empty source which executes a callback function
 pub struct EmptyCallback<S> {
     pub phantom_data: PhantomData<S>,
@@ -52,4 +54,9 @@ where
     fn total_duration(&self) -> Option<Duration> {
         Some(Duration::new(0, 0))
     }
+
+    #[inline]
+    fn try_seek(&mut self, _: Duration) -> Result<(), SeekNotSupported> {
+        Err(SeekNotSupported)
+    }
 }

src/source/fadein.rs

@@ -2,6 +2,8 @@ use std::time::Duration;
 
 use crate::{Sample, Source};
 
+use super::SeekNotSupported;
+
 /// Internal function that builds a `FadeIn` object.
 pub fn fadein<I>(input: I, duration: Duration) -> FadeIn<I>
 where
@@ -105,4 +107,9 @@ where
     fn total_duration(&self) -> Option<Duration> {
         self.input.total_duration()
     }
+
+    #[inline]
+    fn try_seek(&mut self, pos: Duration) -> Result<(), SeekNotSupported> {
+        self.input.try_seek(pos)
+    }
 }

src/source/from_iter.rs

@@ -2,6 +2,8 @@ use std::time::Duration;
 
 use crate::{Sample, Source};
 
+use super::SeekNotSupported;
+
 /// Builds a source that chains sources provided by an iterator.
 ///
 /// The `iterator` parameter is an iterator that produces a source. The source is then played.
@@ -135,6 +137,15 @@ where
     fn total_duration(&self) -> Option<Duration> {
         None
     }
+
+    #[inline]
+    fn try_seek(&mut self, pos: Duration) -> Result<(), SeekNotSupported> {
+        if let Some(source) = self.current_source.as_mut() {
+            source.try_seek(pos)
+        } else {
+            Ok(())
+        }
+    }
 }
 
 #[cfg(test)]

src/source/mix.rs

@@ -1,6 +1,7 @@
 use std::cmp;
 use std::time::Duration;
 
+use crate::source::SeekNotSupported;
 use crate::source::uniform::UniformSourceIterator;
 use crate::{Sample, Source};
 use cpal::{FromSample, Sample as CpalSample};
@@ -119,4 +120,10 @@ where
             _ => None,
         }
     }
+
+    #[inline]
+    fn try_seek(&mut self, pos: Duration) -> Result<(), SeekNotSupported> {
+        self.input1.try_seek(pos)?;
+        self.input1.try_seek(pos)
+    }
 }

src/source/mod.rs

@@ -355,6 +355,8 @@ where
         blt::high_pass(self, freq)
     }
 
+    /// Set position
+    ///
     /// Try to seek to a pos, returns [`SeekNotSupported`] if seeking is not 
     /// supported by the current source.
     fn try_seek(&mut self, _: Duration) -> Result<(), SeekNotSupported> {
@@ -362,7 +364,7 @@ where
     }
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq, Eq)]
 pub struct SeekNotSupported;
 
 impl fmt::Display for SeekNotSupported {
@@ -396,6 +398,11 @@ where
     fn total_duration(&self) -> Option<Duration> {
         (**self).total_duration()
     }
+
+    #[inline]
+    fn try_seek(&mut self, pos: Duration) -> Result<(), SeekNotSupported> {
+        (**self).try_seek(pos)
+    }
 }
 
 impl<S> Source for Box<dyn Source<Item = S> + Send>
@@ -421,6 +428,11 @@ where
     fn total_duration(&self) -> Option<Duration> {
         (**self).total_duration()
     }
+
+    #[inline]
+    fn try_seek(&mut self, pos: Duration) -> Result<(), SeekNotSupported> {
+        (**self).try_seek(pos)
+    }
 }
 
 impl<S> Source for Box<dyn Source<Item = S> + Send + Sync>
@@ -446,5 +458,10 @@ where
     fn total_duration(&self) -> Option<Duration> {
         (**self).total_duration()
     }
+
+    #[inline]
+    fn try_seek(&mut self, pos: Duration) -> Result<(), SeekNotSupported> {
+        (**self).try_seek(pos)
+    }
 }
 

src/source/pausable.rs

@@ -2,6 +2,8 @@ use std::time::Duration;
 
 use crate::{Sample, Source};
 
+use super::SeekNotSupported;
+
 /// Internal function that builds a `Pausable` object.
 pub fn pausable<I>(source: I, paused: bool) -> Pausable<I>
 where
@@ -115,4 +117,9 @@ where
     fn total_duration(&self) -> Option<Duration> {
         self.input.total_duration()
     }
+
+    #[inline]
+    fn try_seek(&mut self, pos: Duration) -> Result<(), SeekNotSupported> {
+        self.input.try_seek(pos)
+    }
 }

src/source/periodic.rs

@@ -2,6 +2,8 @@ use std::time::Duration;
 
 use crate::{Sample, Source};
 
+use super::SeekNotSupported;
+
 /// Internal function that builds a `PeriodicAccess` object.
 pub fn periodic<I, F>(source: I, period: Duration, modifier: F) -> PeriodicAccess<I, F>
 where
@@ -117,6 +119,11 @@ where
     fn total_duration(&self) -> Option<Duration> {
         self.input.total_duration()
     }
+
+    #[inline]
+    fn try_seek(&mut self, pos: Duration) -> Result<(), SeekNotSupported> {
+        self.input.try_seek(pos)
+    }
 }
 
 #[cfg(test)]

src/source/repeat.rs

@@ -4,6 +4,8 @@ use crate::source::buffered::Buffered;
 
 use crate::{Sample, Source};
 
+use super::SeekNotSupported;
+
 /// Internal function that builds a `Repeat` object.
 pub fn repeat<I>(input: I) -> Repeat<I>
 where
@@ -84,6 +86,11 @@ where
     fn total_duration(&self) -> Option<Duration> {
         None
     }
+
+    #[inline]
+    fn try_seek(&mut self, pos: Duration) -> Result<(), SeekNotSupported> {
+        self.inner.try_seek(pos)
+    }
 }
 
 impl<I> Clone for Repeat<I>

src/source/samples_converter.rs

@@ -4,6 +4,8 @@ use std::time::Duration;
 use crate::{Sample, Source};
 use cpal::{FromSample, Sample as CpalSample};
 
+use super::SeekNotSupported;
+
 /// An iterator that reads from a `Source` and converts the samples to a specific rate and
 /// channels count.
 ///
@@ -95,4 +97,9 @@ where
     fn total_duration(&self) -> Option<Duration> {
         self.inner.total_duration()
     }
+
+    #[inline]
+    fn try_seek(&mut self, pos: Duration) -> Result<(), SeekNotSupported> {
+        self.inner.try_seek(pos)
+    }
 }

src/source/sine.rs

@@ -3,6 +3,8 @@ use std::time::Duration;
 
 use crate::Source;
 
+use super::SeekNotSupported;
+
 /// An infinite source that produces a sine.
 ///
 /// Always has a rate of 48kHz and one channel.
@@ -17,7 +19,7 @@ impl SineWave {
     #[inline]
     pub fn new(freq: f32) -> SineWave {
         SineWave {
-            freq: freq,
+            freq,
             num_sample: 0,
         }
     }
@@ -55,4 +57,12 @@ impl Source for SineWave {
     fn total_duration(&self) -> Option<Duration> {
         None
     }
+
+    #[inline]
+    fn try_seek(&mut self, _: Duration) -> Result<(), SeekNotSupported> {
+        // It is possible to write an implementation that skips the right
+        // amount of samples to get into the right phase. I do not think there
+        // is a use case for that however.
+        Err(SeekNotSupported)
+    }
 }

src/source/skip.rs

@@ -2,6 +2,8 @@ use std::time::Duration;
 
 use crate::{Sample, Source};
 
+use super::SeekNotSupported;
+
 const NS_PER_SECOND: u128 = 1_000_000_000;
 
 /// Internal function that builds a `SkipDuration` object.
@@ -157,6 +159,11 @@ where
                 .unwrap_or_else(|| Duration::from_secs(0))
         })
     }
+
+    #[inline]
+    fn try_seek(&mut self, pos: Duration) -> Result<(), SeekNotSupported> {
+        self.input.try_seek(pos)
+    }
 }
 
 #[cfg(test)]

src/source/skippable.rs

@@ -3,6 +3,8 @@ use std::time::Duration;
 use crate::Sample;
 use crate::Source;
 
+use super::SeekNotSupported;
+
 /// Internal function that builds a `Skippable` object.
 pub fn skippable<I>(source: I) -> Skippable<I> {
     Skippable {
@@ -89,4 +91,9 @@ where
     fn total_duration(&self) -> Option<Duration> {
         self.input.total_duration()
     }
+
+    #[inline]
+    fn try_seek(&mut self, pos: Duration) -> Result<(), SeekNotSupported> {
+        self.input.try_seek(pos)
+    }
 }

src/source/spatial.rs

@@ -3,6 +3,8 @@ use std::time::Duration;
 use crate::source::ChannelVolume;
 use crate::{Sample, Source};
 
+use super::SeekNotSupported;
+
 /// Combines channels in input into a single mono source, then plays that mono sound
 /// to each channel at the volume given for that channel.
 #[derive(Clone)]
@@ -117,4 +119,9 @@ where
     fn total_duration(&self) -> Option<Duration> {
         self.input.total_duration()
     }
+
+    #[inline]
+    fn try_seek(&mut self, pos: Duration) -> Result<(), SeekNotSupported> {
+        self.input.try_seek(pos)
+    }
 }

src/source/speed.rs

@@ -2,6 +2,8 @@ use std::time::Duration;
 
 use crate::{Sample, Source};
 
+use super::SeekNotSupported;
+
 /// Internal function that builds a `Speed` object.
 pub fn speed<I>(input: I, factor: f32) -> Speed<I> {
     Speed { input, factor }
@@ -91,16 +93,17 @@ where
 
     #[inline]
     fn total_duration(&self) -> Option<Duration> {
-        // TODO: the crappy API of duration makes this code difficult to write
-        if let Some(duration) = self.input.total_duration() {
-            let as_ns = duration.as_secs() * 1000000000 + duration.subsec_nanos() as u64;
-            let new_val = (as_ns as f32 / self.factor) as u64;
-            Some(Duration::new(
-                new_val / 1000000000,
-                (new_val % 1000000000) as u32,
-            ))
-        } else {
-            None
-        }
+        self.input.total_duration().map(|d| d.mul_f32(self.factor))
+    }
+
+    #[inline]
+    fn try_seek(&mut self, pos: Duration) -> Result<(), SeekNotSupported> {
+        /* TODO: This might be wrong, I do not know how speed achieves its speedup
+         * so I can not reason about the correctness.
+         * <dvdsk noreply@davidsk.dev> */
+
+        // even after 24 hours of playback f32 has enough precision
+        let pos_accounting_for_speedup = pos.mul_f32(self.factor);
+        self.input.try_seek(pos_accounting_for_speedup)
     }
 }

src/source/stoppable.rs

@@ -2,6 +2,8 @@ use std::time::Duration;
 
 use crate::{Sample, Source};
 
+use super::SeekNotSupported;
+
 /// Internal function that builds a `Stoppable` object.
 pub fn stoppable<I>(source: I) -> Stoppable<I> {
     Stoppable {
@@ -88,4 +90,9 @@ where
     fn total_duration(&self) -> Option<Duration> {
         self.input.total_duration()
     }
+
+    #[inline]
+    fn try_seek(&mut self, pos: Duration) -> Result<(), SeekNotSupported> {
+        self.input.try_seek(pos)
+    }
 }

src/source/take.rs

@@ -2,6 +2,8 @@ use std::time::Duration;
 
 use crate::{Sample, Source};
 
+use super::SeekNotSupported;
+
 /// Internal function that builds a `TakeDuration` object.
 pub fn take_duration<I>(input: I, duration: Duration) -> TakeDuration<I>
 where
@@ -176,4 +178,9 @@ where
             None
         }
     }
+
+    #[inline]
+    fn try_seek(&mut self, pos: Duration) -> Result<(), SeekNotSupported> {
+        self.input.try_seek(pos)
+    }
 }

src/source/uniform.rs

@@ -6,6 +6,8 @@ use cpal::FromSample;
 use crate::conversions::{ChannelCountConverter, DataConverter, SampleRateConverter};
 use crate::{Sample, Source};
 
+use super::SeekNotSupported;
+
 /// An iterator that reads from a `Source` and converts the samples to a specific rate and
 /// channels count.
 ///
@@ -137,6 +139,20 @@ where
     fn total_duration(&self) -> Option<Duration> {
         self.total_duration
     }
+
+    #[inline]
+    fn try_seek(&mut self, pos: Duration) -> Result<(), SeekNotSupported> {
+        if let Some(input) = self.inner.as_mut() {
+            input
+                .inner_mut()
+                .inner_mut()
+                .inner_mut()
+                .inner_mut()
+                .try_seek(pos)
+        } else {
+            Ok(())
+        }
+    }
 }
 
 #[derive(Clone, Debug)]
@@ -145,6 +161,13 @@ struct Take<I> {
     n: Option<usize>,
 }
 
+impl<I> Take<I> {
+    #[inline]
+    pub fn inner_mut(&mut self) -> &mut I {
+        &mut self.iter
+    }
+}
+
 impl<I> Iterator for Take<I>
 where
     I: Iterator,

src/source/zero.rs

@@ -3,6 +3,8 @@ use std::time::Duration;
 
 use crate::{Sample, Source};
 
+use super::SeekNotSupported;
+
 /// An infinite source that produces zero.
 #[derive(Clone, Debug)]
 pub struct Zero<S> {
@@ -77,4 +79,9 @@ where
     fn total_duration(&self) -> Option<Duration> {
         None
     }
+
+    #[inline]
+    fn try_seek(&mut self, _: Duration) -> Result<(), SeekNotSupported> {
+        Ok(())
+    }
 }

tests/seek_error.rs

@@ -0,0 +1,28 @@
+use std::io::BufReader;
+use std::time::Duration;
+
+// hound wav decoder does not support seeking
+#[cfg(feature = "hound")]
+#[test]
+fn seek_not_supported_returns_err() {
+    let (_stream, handle) = rodio::OutputStream::try_default().unwrap();
+    let sink = rodio::Sink::try_new(&handle).unwrap();
+
+    let file = std::fs::File::open("assets/music.wav").unwrap();
+    sink.append(rodio::Decoder::new(BufReader::new(file)).unwrap());
+    let res = sink.try_seek(Duration::from_secs(5));
+    assert_eq!(res, Err(rodio::source::SeekNotSupported));
+}
+
+// mp3 decoder does support seeking
+#[cfg(feature = "mp3")]
+#[test]
+fn seek_supported_returns_ok() {
+    let (_stream, handle) = rodio::OutputStream::try_default().unwrap();
+    let sink = rodio::Sink::try_new(&handle).unwrap();
+
+    let file = std::fs::File::open("assets/music.mp3").unwrap();
+    sink.append(rodio::Decoder::new(BufReader::new(file)).unwrap());
+    let res = sink.try_seek(Duration::from_secs(5));
+    assert_eq!(res, Ok(()));
+}