Make playback state an enum

src/lib.rs

@@ -4,7 +4,7 @@ mod error;
 use error::{Error, MpdResult};
 use itertools::Itertools;
 mod structs;
-pub use structs::{Position, Stats, Status, Track};
+pub use structs::{Position, Stats, Status, Track, State};
 
 /// some unprintable character to separate repeated keys
 const SEPARATOR: char = '\x02';
@@ -202,7 +202,7 @@ OK";
         playlist: 6,
         playlistlength: 5364,
         mixrampdb: 0.0,
-        state: String::from("play"),
+        state: State::Play,
         song: Some(3833),
         songid: Some(3834),
         elapsed: Some(Duration::from_secs_f64(69.642)),

src/structs.rs

@@ -89,8 +89,8 @@ pub struct Status {
   pub playlist:       u32,
   // mpd returns 0 if there is no current playlist
   pub playlistlength: u32,
-  // play, stop, pause. TODO: make an enum
+  #[serde(deserialize_with = "de_state")]
-  pub state:          String,
+  pub state:          State,
   pub song:           Option<u32>,
   pub songid:         Option<u32>,
   pub nextsong:       Option<u32>,
@@ -112,6 +112,20 @@ pub struct Status {
   pub error:          Option<String>,
 }
 
+#[derive(Deserialize, Clone, Debug, PartialEq)]
+pub enum State {
+  Stop,
+  Play,
+  Pause,
+}
+
+// Default implementation so I can derive default for containing structs.
+impl Default for State {
+  fn default() -> Self {
+    Self::Stop
+  }
+}
+
 /// Database statistics as returned by the `stats` command.
 #[derive(Deserialize, Clone, Debug, Default, PartialEq)]
 #[serde(default)]
@@ -150,6 +164,20 @@ mod helpers {
     f64::deserialize(deserializer).map(Duration::from_secs_f64).map(Some)
   }
 
+  /// Deserialize the playback state.
+  pub fn de_state<'de, D>(deserializer: D) -> Result<State, D::Error>
+  where D: de::Deserializer<'de> {
+    match String::deserialize(deserializer)?.as_ref() {
+      "play" => Ok(State::Play),
+      "pause" => Ok(State::Pause),
+      "stop" => Ok(State::Stop),
+      s => Err(de::Error::invalid_value(
+        de::Unexpected::Str(s),
+        &"expected one of play, pause, or stop",
+      )),
+    }
+  }
+
   pub fn de_string_or_vec<'de, D>(deserializer: D) -> Result<Vec<String>, D::Error>
   where D: de::Deserializer<'de> {
     String::deserialize(deserializer).map(|s| s.split(SEPARATOR).map(std::string::String::from).collect())