TrackHandle: add metadata field (#25)

* Adds metadata field to TrackHandle.

Co-authored-by: Kyle Simpson <kyleandrew.simpson@gmail.com>

src/tracks/handle.rs

@@ -1,6 +1,9 @@
 use super::*;
-use crate::events::{Event, EventData, EventHandler};
-use std::time::Duration;
+use crate::{
+    events::{Event, EventData, EventHandler},
+    input::Metadata,
+};
+use std::{sync::Arc, time::Duration};
 use tokio::sync::{
     mpsc::{error::SendError, UnboundedSender},
     oneshot,
@@ -20,18 +23,25 @@ pub struct TrackHandle {
     command_channel: UnboundedSender<TrackCommand>,
     seekable: bool,
     uuid: Uuid,
+    metadata: Arc<Metadata>,
 }
 
 impl TrackHandle {
     /// Creates a new handle, using the given command sink and hint as to whether
     /// the underlying [`Input`] supports seek operations.
     ///
     /// [`Input`]: crate::input::Input
-    pub fn new(command_channel: UnboundedSender<TrackCommand>, seekable: bool, uuid: Uuid) -> Self {
+    pub fn new(
+        command_channel: UnboundedSender<TrackCommand>,
+        seekable: bool,
+        uuid: Uuid,
+        metadata: Metadata,
+    ) -> Self {
         Self {
             command_channel,
             seekable,
             uuid,
+            metadata: Arc::new(metadata),
         }
     }
 
@@ -157,6 +167,17 @@ impl TrackHandle {
         self.uuid
     }
 
+    /// Returns the metadata stored in the handle.
+    ///
+    /// Metadata is cloned from the inner [`Input`] at
+    /// the time a track/handle is created, and is effectively
+    /// read-only from then on.
+    ///
+    /// [`Input`]: crate::input::Input
+    pub fn metadata(&self) -> Arc<Metadata> {
+        self.metadata.clone()
+    }
+
     #[inline]
     /// Send a raw command to the [`Track`] object.
     ///

src/tracks/mod.rs

@@ -366,7 +366,8 @@ impl Track {
 pub fn create_player(source: Input) -> (Track, TrackHandle) {
     let (tx, rx) = mpsc::unbounded_channel();
     let can_seek = source.is_seekable();
-    let handle = TrackHandle::new(tx, can_seek, Uuid::new_v4());
+    let metadata = source.metadata.clone();
+    let handle = TrackHandle::new(tx, can_seek, Uuid::new_v4(), metadata);
 
     let player = Track::new_raw(source, rx, handle.clone());