Some code cleanup

src/metadata.rs

@@ -3,46 +3,51 @@ use std::path::Path;
 use lofty::file::TaggedFileExt;
 use lofty::tag::ItemKey;
 
-/// Extract the artist name from a music file.
+/// Tags that can be read from a music file.
+pub enum Tag {
+    ArtistName,
+    ArtistMbid,
+    TrackTitle,
+    TrackMbid,
+}
+
+impl Tag {
+    fn item_key(&self) -> ItemKey {
+        match self {
+            Tag::ArtistName => ItemKey::TrackArtist,
+            Tag::ArtistMbid => ItemKey::MusicBrainzArtistId,
+            Tag::TrackTitle => ItemKey::TrackTitle,
+            Tag::TrackMbid => ItemKey::MusicBrainzRecordingId,
+        }
+    }
+}
+
+fn read_tag(path: &Path, key: ItemKey) -> Result<Option<String>, lofty::error::LoftyError> {
+    let tagged_file = lofty::read_from_path(path)?;
+    let Some(tag) = tagged_file.primary_tag().or_else(|| tagged_file.first_tag()) else {
+        return Ok(None);
+    };
+    Ok(tag.get_string(key).map(String::from))
+}
+
+/// Read multiple tags from a music file in a single file open.
+/// Returns a Vec in the same order as the input keys.
+pub fn read_tags(path: &Path, keys: &[Tag]) -> Result<Vec<Option<String>>, lofty::error::LoftyError> {
+    let tagged_file = lofty::read_from_path(path)?;
+    let Some(tag) = tagged_file.primary_tag().or_else(|| tagged_file.first_tag()) else {
+        return Ok(vec![None; keys.len()]);
+    };
+    Ok(keys
+        .iter()
+        .map(|k| tag.get_string(k.item_key()).map(String::from))
+        .collect())
+}
+
 pub fn read_artist_name(path: &Path) -> Result<Option<String>, lofty::error::LoftyError> {
-    let tagged_file = lofty::read_from_path(path)?;
-
-    let Some(tag) = tagged_file.primary_tag().or_else(|| tagged_file.first_tag()) else {
-        return Ok(None);
-    };
-
-    Ok(tag.get_string(ItemKey::TrackArtist).map(String::from))
+    read_tag(path, ItemKey::TrackArtist)
 }
 
-/// Extract the MusicBrainz artist ID from a music file.
 pub fn read_artist_mbid(path: &Path) -> Result<Option<String>, lofty::error::LoftyError> {
-    let tagged_file = lofty::read_from_path(path)?;
-
-    let Some(tag) = tagged_file.primary_tag().or_else(|| tagged_file.first_tag()) else {
-        return Ok(None);
-    };
-
-    Ok(tag.get_string(ItemKey::MusicBrainzArtistId).map(String::from))
+    read_tag(path, ItemKey::MusicBrainzArtistId)
 }
 
-/// Extract the track title from a music file.
-pub fn read_track_title(path: &Path) -> Result<Option<String>, lofty::error::LoftyError> {
-    let tagged_file = lofty::read_from_path(path)?;
-
-    let Some(tag) = tagged_file.primary_tag().or_else(|| tagged_file.first_tag()) else {
-        return Ok(None);
-    };
-
-    Ok(tag.get_string(ItemKey::TrackTitle).map(String::from))
-}
-
-/// Extract the MusicBrainz recording ID from a music file.
-pub fn read_track_mbid(path: &Path) -> Result<Option<String>, lofty::error::LoftyError> {
-    let tagged_file = lofty::read_from_path(path)?;
-
-    let Some(tag) = tagged_file.primary_tag().or_else(|| tagged_file.first_tag()) else {
-        return Ok(None);
-    };
-
-    Ok(tag.get_string(ItemKey::MusicBrainzRecordingId).map(String::from))
-}