Ensure consistency between in-memory and database state (#146)

Closes #120

Reviewed-on: #146

src/bin/musichoard-edit.rs

@@ -77,10 +77,6 @@ struct ArtistSortValue {
 
 #[derive(StructOpt, Debug)]
 enum MusicBrainzCommand {
-    #[structopt(about = "Add a MusicBrainz URL without overwriting the existing value")]
-    Add(MusicBrainzValue),
-    #[structopt(about = "Remove the MusicBrainz URL")]
-    Remove(MusicBrainzValue),
     #[structopt(about = "Set the MusicBrainz URL overwriting any existing value")]
     Set(MusicBrainzValue),
     #[structopt(about = "Clear the MusicBrainz URL)")]
@@ -129,10 +125,14 @@ impl ArtistCommand {
     fn handle(self, music_hoard: &mut MH) {
         match self {
             ArtistCommand::Add(artist_value) => {
-                music_hoard.add_artist(ArtistId::new(artist_value.artist));
+                music_hoard
+                    .add_artist(ArtistId::new(artist_value.artist))
+                    .expect("failed to add artist");
             }
             ArtistCommand::Remove(artist_value) => {
-                music_hoard.remove_artist(ArtistId::new(artist_value.artist));
+                music_hoard
+                    .remove_artist(ArtistId::new(artist_value.artist))
+                    .expect("failed to remove artist");
             }
             ArtistCommand::Sort(sort_command) => {
                 sort_command.handle(music_hoard);
@@ -166,18 +166,6 @@ impl SortCommand {
 impl MusicBrainzCommand {
     fn handle(self, music_hoard: &mut MH) {
         match self {
-            MusicBrainzCommand::Add(musicbrainz_value) => music_hoard
-                .add_musicbrainz_url(
-                    ArtistId::new(musicbrainz_value.artist),
-                    musicbrainz_value.url,
-                )
-                .expect("failed to add MusicBrainz URL"),
-            MusicBrainzCommand::Remove(musicbrainz_value) => music_hoard
-                .remove_musicbrainz_url(
-                    ArtistId::new(musicbrainz_value.artist),
-                    musicbrainz_value.url,
-                )
-                .expect("failed to remove MusicBrainz URL"),
             MusicBrainzCommand::Set(musicbrainz_value) => music_hoard
                 .set_musicbrainz_url(
                     ArtistId::new(musicbrainz_value.artist),
@@ -227,14 +215,9 @@ fn main() {
 
     let db = JsonDatabase::new(JsonDatabaseFileBackend::new(&opt.database_file_path));
 
-    let mut music_hoard = MusicHoardBuilder::default().set_database(db).build();
+    let mut music_hoard = MusicHoardBuilder::default()
-    music_hoard
+        .set_database(db)
-        .load_from_database()
+        .build()
-        .expect("failed to load database");
+        .expect("failed to initialise MusicHoard");
-
     opt.category.handle(&mut music_hoard);
-
-    music_hoard
-        .save_to_database()
-        .expect("failed to save database");
 }

src/core/collection/artist.rs

@@ -53,38 +53,8 @@ impl Artist {
         _ = self.sort.take();
     }
 
-    pub fn add_musicbrainz_url<S: AsRef<str>>(&mut self, url: S) -> Result<(), Error> {
+    pub fn set_musicbrainz_url(&mut self, url: MusicBrainz) {
-        let url: MusicBrainz = url.as_ref().try_into()?;
+        _ = self.musicbrainz.insert(url);
-
-        match &self.musicbrainz {
-            Some(current) => {
-                if current != &url {
-                    return Err(Error::UrlError(format!(
-                        "artist already has a different URL: {current}"
-                    )));
-                }
-            }
-            None => {
-                _ = self.musicbrainz.insert(url);
-            }
-        }
-
-        Ok(())
-    }
-
-    pub fn remove_musicbrainz_url<S: AsRef<str>>(&mut self, url: S) -> Result<(), Error> {
-        let url = url.as_ref().try_into()?;
-
-        if self.musicbrainz == Some(url) {
-            _ = self.musicbrainz.take();
-        }
-
-        Ok(())
-    }
-
-    pub fn set_musicbrainz_url<S: AsRef<str>>(&mut self, url: S) -> Result<(), Error> {
-        _ = self.musicbrainz.insert(url.as_ref().try_into()?);
-        Ok(())
     }
 
     pub fn clear_musicbrainz_url(&mut self) {
@@ -227,12 +197,6 @@ impl TryFrom<&str> for MusicBrainz {
     }
 }
 
-impl Display for MusicBrainz {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(f, "{}", self.0)
-    }
-}
-
 impl IMbid for MusicBrainz {
     fn mbid(&self) -> &str {
         // The URL is assumed to have been validated.
@@ -326,40 +290,12 @@ mod tests {
     }
 
     #[test]
-    fn add_remove_musicbrainz_url() {
+    fn musicbrainz_url() {
-        let mut artist = Artist::new(ArtistId::new("an artist"));
+        let result: Result<MusicBrainz, Error> = MUSICBUTLER.try_into();
+        assert!(result.is_err());
 
-        let mut expected: Option<MusicBrainz> = None;
+        let result: Result<MusicBrainz, Error> = MUSICBRAINZ.try_into();
-        assert_eq!(artist.musicbrainz, expected);
+        assert!(result.is_ok());
-
-        // Adding incorect URL is an error.
-        assert!(artist.add_musicbrainz_url(MUSICBUTLER).is_err());
-        assert_eq!(artist.musicbrainz, expected);
-
-        // Adding URL to artist.
-        assert!(artist.add_musicbrainz_url(MUSICBRAINZ).is_ok());
-        _ = expected.insert(MusicBrainz::new(MUSICBRAINZ).unwrap());
-        assert_eq!(artist.musicbrainz, expected);
-
-        // Adding the same URL again is ok, but does not do anything.
-        assert!(artist.add_musicbrainz_url(MUSICBRAINZ).is_ok());
-        assert_eq!(artist.musicbrainz, expected);
-
-        // Adding further URLs is an error.
-        assert!(artist.add_musicbrainz_url(MUSICBRAINZ_2).is_err());
-        assert_eq!(artist.musicbrainz, expected);
-
-        // Removing a URL not in the collection is okay, but does not do anything.
-        assert!(artist.remove_musicbrainz_url(MUSICBRAINZ_2).is_ok());
-        assert_eq!(artist.musicbrainz, expected);
-
-        // Removing a URL in the collection removes it.
-        assert!(artist.remove_musicbrainz_url(MUSICBRAINZ).is_ok());
-        _ = expected.take();
-        assert_eq!(artist.musicbrainz, expected);
-
-        assert!(artist.remove_musicbrainz_url(MUSICBRAINZ).is_ok());
-        assert_eq!(artist.musicbrainz, expected);
     }
 
     #[test]
@@ -369,19 +305,15 @@ mod tests {
         let mut expected: Option<MusicBrainz> = None;
         assert_eq!(artist.musicbrainz, expected);
 
-        // Setting an incorrect URL is an error.
-        assert!(artist.set_musicbrainz_url(MUSICBUTLER).is_err());
-        assert_eq!(artist.musicbrainz, expected);
-
         // Setting a URL on an artist.
-        assert!(artist.set_musicbrainz_url(MUSICBRAINZ).is_ok());
+        artist.set_musicbrainz_url(MUSICBRAINZ.try_into().unwrap());
         _ = expected.insert(MusicBrainz::new(MUSICBRAINZ).unwrap());
         assert_eq!(artist.musicbrainz, expected);
 
-        assert!(artist.set_musicbrainz_url(MUSICBRAINZ).is_ok());
+        artist.set_musicbrainz_url(MUSICBRAINZ.try_into().unwrap());
         assert_eq!(artist.musicbrainz, expected);
 
-        assert!(artist.set_musicbrainz_url(MUSICBRAINZ_2).is_ok());
+        artist.set_musicbrainz_url(MUSICBRAINZ_2.try_into().unwrap());
         _ = expected.insert(MusicBrainz::new(MUSICBRAINZ_2).unwrap());
         assert_eq!(artist.musicbrainz, expected);
 

src/core/musichoard/musichoard.rs

@@ -14,169 +14,51 @@ use crate::core::{
 
 /// The Music Hoard. It is responsible for pulling information from both the library and the
 /// database, ensuring its consistent and writing back any changes.
+#[derive(Debug)]
 pub struct MusicHoard<LIB, DB> {
     collection: Collection,
+    pre_commit: Collection,
     library: LIB,
     database: DB,
-    // There is no database cache since the database contains the entirety of the `collection`
-    // itself. Therefore, [`collection`] also represents the last state of the database.
     library_cache: HashMap<ArtistId, Artist>,
+    database_cache: Collection,
 }
 
 /// Phantom type for when a library implementation is not needed.
+#[derive(Debug)]
 pub struct NoLibrary;
 
 /// Phantom type for when a database implementation is not needed.
+#[derive(Debug)]
 pub struct NoDatabase;
 
 impl Default for MusicHoard<NoLibrary, NoDatabase> {
     /// Create a new [`MusicHoard`] without any library or database.
     fn default() -> Self {
-        MusicHoard::new(NoLibrary, NoDatabase)
+        MusicHoard::empty()
+    }
+}
+
+impl MusicHoard<NoLibrary, NoDatabase> {
+    /// Create a new [`MusicHoard`] without any library or database.
+    pub fn empty() -> Self {
+        MusicHoard {
+            collection: vec![],
+            pre_commit: vec![],
+            library: NoLibrary,
+            database: NoDatabase,
+            library_cache: HashMap::new(),
+            database_cache: vec![],
+        }
     }
 }
 
 impl<LIB, DB> MusicHoard<LIB, DB> {
-    /// Create a new [`MusicHoard`] with the provided [`ILibrary`] and [`IDatabase`].
-    pub fn new(library: LIB, database: DB) -> Self {
-        MusicHoard {
-            collection: vec![],
-            library,
-            database,
-            library_cache: HashMap::new(),
-        }
-    }
-
     /// Retrieve the [`Collection`].
     pub fn get_collection(&self) -> &Collection {
         &self.collection
     }
 
-    pub fn add_artist<ID: Into<ArtistId>>(&mut self, artist_id: ID) {
-        let artist_id: ArtistId = artist_id.into();
-
-        if self.get_artist(&artist_id).is_none() {
-            self.collection.push(Artist::new(artist_id));
-            Self::sort_artists(&mut self.collection);
-        }
-    }
-
-    pub fn remove_artist<ID: AsRef<ArtistId>>(&mut self, artist_id: ID) {
-        let index_opt = self
-            .collection
-            .iter()
-            .position(|a| &a.id == artist_id.as_ref());
-
-        if let Some(index) = index_opt {
-            self.collection.remove(index);
-        }
-    }
-
-    pub fn set_artist_sort<ID: AsRef<ArtistId>, SORT: Into<ArtistId>>(
-        &mut self,
-        artist_id: ID,
-        artist_sort: SORT,
-    ) -> Result<(), Error> {
-        self.get_artist_mut_or_err(artist_id.as_ref())?
-            .set_sort_key(artist_sort);
-        Self::sort(&mut self.collection);
-        Ok(())
-    }
-
-    pub fn clear_artist_sort<ID: AsRef<ArtistId>>(&mut self, artist_id: ID) -> Result<(), Error> {
-        self.get_artist_mut_or_err(artist_id.as_ref())?
-            .clear_sort_key();
-        Self::sort(&mut self.collection);
-        Ok(())
-    }
-
-    pub fn add_musicbrainz_url<ID: AsRef<ArtistId>, S: AsRef<str>>(
-        &mut self,
-        artist_id: ID,
-        url: S,
-    ) -> Result<(), Error> {
-        Ok(self
-            .get_artist_mut_or_err(artist_id.as_ref())?
-            .add_musicbrainz_url(url)?)
-    }
-
-    pub fn remove_musicbrainz_url<ID: AsRef<ArtistId>, S: AsRef<str>>(
-        &mut self,
-        artist_id: ID,
-        url: S,
-    ) -> Result<(), Error> {
-        Ok(self
-            .get_artist_mut_or_err(artist_id.as_ref())?
-            .remove_musicbrainz_url(url)?)
-    }
-
-    pub fn set_musicbrainz_url<ID: AsRef<ArtistId>, S: AsRef<str>>(
-        &mut self,
-        artist_id: ID,
-        url: S,
-    ) -> Result<(), Error> {
-        Ok(self
-            .get_artist_mut_or_err(artist_id.as_ref())?
-            .set_musicbrainz_url(url)?)
-    }
-
-    pub fn clear_musicbrainz_url<ID: AsRef<ArtistId>>(
-        &mut self,
-        artist_id: ID,
-    ) -> Result<(), Error> {
-        self.get_artist_mut_or_err(artist_id.as_ref())?
-            .clear_musicbrainz_url();
-        Ok(())
-    }
-
-    pub fn add_to_property<ID: AsRef<ArtistId>, S: AsRef<str> + Into<String>>(
-        &mut self,
-        artist_id: ID,
-        property: S,
-        values: Vec<S>,
-    ) -> Result<(), Error> {
-        self.get_artist_mut_or_err(artist_id.as_ref())?
-            .add_to_property(property, values);
-        Ok(())
-    }
-
-    pub fn remove_from_property<ID: AsRef<ArtistId>, S: AsRef<str>>(
-        &mut self,
-        artist_id: ID,
-        property: S,
-        values: Vec<S>,
-    ) -> Result<(), Error> {
-        self.get_artist_mut_or_err(artist_id.as_ref())?
-            .remove_from_property(property, values);
-        Ok(())
-    }
-
-    pub fn set_property<ID: AsRef<ArtistId>, S: AsRef<str> + Into<String>>(
-        &mut self,
-        artist_id: ID,
-        property: S,
-        values: Vec<S>,
-    ) -> Result<(), Error> {
-        self.get_artist_mut_or_err(artist_id.as_ref())?
-            .set_property(property, values);
-        Ok(())
-    }
-
-    pub fn clear_property<ID: AsRef<ArtistId>, S: AsRef<str>>(
-        &mut self,
-        artist_id: ID,
-        property: S,
-    ) -> Result<(), Error> {
-        self.get_artist_mut_or_err(artist_id.as_ref())?
-            .clear_property(property);
-        Ok(())
-    }
-
-    fn sort(collection: &mut [Artist]) {
-        Self::sort_artists(collection);
-        Self::sort_albums_and_tracks(collection.iter_mut());
-    }
-
     fn sort_artists(collection: &mut [Artist]) {
         collection.sort_unstable();
     }
@@ -192,15 +74,18 @@ impl<LIB, DB> MusicHoard<LIB, DB> {
 
     fn merge_collections(&mut self) {
         let mut primary = self.library_cache.clone();
-        for secondary_artist in self.collection.drain(..) {
+        for secondary_artist in self.database_cache.iter().cloned() {
             if let Some(ref mut primary_artist) = primary.get_mut(&secondary_artist.id) {
                 primary_artist.merge_in_place(secondary_artist);
             } else {
                 primary.insert(secondary_artist.id.clone(), secondary_artist);
             }
         }
-        self.collection.extend(primary.into_values());
+
+        self.collection = primary.into_values().collect();
         Self::sort_artists(&mut self.collection);
+
+        self.pre_commit = self.collection.clone();
     }
 
     fn items_to_artists(items: Vec<Item>) -> Result<HashMap<ArtistId, Artist>, Error> {
@@ -272,21 +157,41 @@ impl<LIB, DB> MusicHoard<LIB, DB> {
         Ok(collection)
     }
 
-    fn get_artist(&self, artist_id: &ArtistId) -> Option<&Artist> {
+    fn get_artist<'a>(collection: &'a Collection, artist_id: &ArtistId) -> Option<&'a Artist> {
-        self.collection.iter().find(|a| &a.id == artist_id)
+        collection.iter().find(|a| &a.id == artist_id)
     }
 
-    fn get_artist_mut(&mut self, artist_id: &ArtistId) -> Option<&mut Artist> {
+    fn get_artist_mut<'a>(
-        self.collection.iter_mut().find(|a| &a.id == artist_id)
+        collection: &'a mut Collection,
+        artist_id: &ArtistId,
+    ) -> Option<&'a mut Artist> {
+        collection.iter_mut().find(|a| &a.id == artist_id)
     }
 
-    fn get_artist_mut_or_err(&mut self, artist_id: &ArtistId) -> Result<&mut Artist, Error> {
+    fn get_artist_mut_or_err<'a>(
-        self.get_artist_mut(artist_id).ok_or_else(|| {
+        collection: &'a mut Collection,
+        artist_id: &ArtistId,
+    ) -> Result<&'a mut Artist, Error> {
+        Self::get_artist_mut(collection, artist_id).ok_or_else(|| {
             Error::CollectionError(format!("artist '{}' is not in the collection", artist_id))
         })
     }
 }
 
+impl<LIB: ILibrary> MusicHoard<LIB, NoDatabase> {
+    /// Create a new [`MusicHoard`] with the provided [`ILibrary`] and no database.
+    pub fn library(library: LIB) -> Self {
+        MusicHoard {
+            collection: vec![],
+            pre_commit: vec![],
+            library,
+            database: NoDatabase,
+            library_cache: HashMap::new(),
+            database_cache: vec![],
+        }
+    }
+}
+
 impl<LIB: ILibrary, DB> MusicHoard<LIB, DB> {
     /// Rescan the library and merge with the in-memory collection.
     pub fn rescan_library(&mut self) -> Result<(), Error> {
@@ -299,26 +204,188 @@ impl<LIB: ILibrary, DB> MusicHoard<LIB, DB> {
     }
 }
 
+impl<DB: IDatabase> MusicHoard<NoLibrary, DB> {
+    /// Create a new [`MusicHoard`] with the provided [`IDatabase`] and no library.
+    pub fn database(database: DB) -> Result<Self, Error> {
+        let mut mh = MusicHoard {
+            collection: vec![],
+            pre_commit: vec![],
+            library: NoLibrary,
+            database,
+            library_cache: HashMap::new(),
+            database_cache: vec![],
+        };
+        mh.reload_database()?;
+        Ok(mh)
+    }
+}
+
 impl<LIB, DB: IDatabase> MusicHoard<LIB, DB> {
     /// Load the database and merge with the in-memory collection.
-    pub fn load_from_database(&mut self) -> Result<(), Error> {
+    pub fn reload_database(&mut self) -> Result<(), Error> {
-        self.collection = self.database.load()?;
+        self.database_cache = self.database.load()?;
-        Self::sort_albums_and_tracks(self.collection.iter_mut());
+        Self::sort_albums_and_tracks(self.database_cache.iter_mut());
 
         self.merge_collections();
         Ok(())
     }
 
-    /// Save the in-memory collection to the database.
+    fn commit(&mut self) -> Result<(), Error> {
-    pub fn save_to_database(&mut self) -> Result<(), Error> {
+        if self.collection != self.pre_commit {
-        self.database.save(&self.collection)?;
+            if let Err(err) = self.database.save(&self.pre_commit) {
+                self.pre_commit = self.collection.clone();
+                return Err(err.into());
+            }
+            self.collection = self.pre_commit.clone();
+        }
         Ok(())
     }
+
+    fn update_collection<F>(&mut self, func: F) -> Result<(), Error>
+    where
+        F: FnOnce(&mut Collection),
+    {
+        func(&mut self.pre_commit);
+        self.commit()
+    }
+
+    fn update_artist_and<ID: AsRef<ArtistId>, F1, F2>(
+        &mut self,
+        artist_id: ID,
+        f1: F1,
+        f2: F2,
+    ) -> Result<(), Error>
+    where
+        F1: FnOnce(&mut Artist),
+        F2: FnOnce(&mut Collection),
+    {
+        f1(Self::get_artist_mut_or_err(
+            &mut self.pre_commit,
+            artist_id.as_ref(),
+        )?);
+        self.update_collection(f2)
+    }
+
+    fn update_artist<ID: AsRef<ArtistId>, F>(&mut self, artist_id: ID, func: F) -> Result<(), Error>
+    where
+        F: FnOnce(&mut Artist),
+    {
+        self.update_artist_and(artist_id, func, |_| {})
+    }
+
+    pub fn add_artist<ID: Into<ArtistId>>(&mut self, artist_id: ID) -> Result<(), Error> {
+        let artist_id: ArtistId = artist_id.into();
+
+        self.update_collection(|collection| {
+            if Self::get_artist(collection, &artist_id).is_none() {
+                collection.push(Artist::new(artist_id));
+                Self::sort_artists(collection);
+            }
+        })
+    }
+
+    pub fn remove_artist<ID: AsRef<ArtistId>>(&mut self, artist_id: ID) -> Result<(), Error> {
+        self.update_collection(|collection| {
+            let index_opt = collection.iter().position(|a| &a.id == artist_id.as_ref());
+            if let Some(index) = index_opt {
+                collection.remove(index);
+            }
+        })
+    }
+
+    pub fn set_artist_sort<ID: AsRef<ArtistId>, SORT: Into<ArtistId>>(
+        &mut self,
+        artist_id: ID,
+        artist_sort: SORT,
+    ) -> Result<(), Error> {
+        self.update_artist_and(
+            artist_id,
+            |artist| artist.set_sort_key(artist_sort),
+            |collection| Self::sort_artists(collection),
+        )
+    }
+
+    pub fn clear_artist_sort<ID: AsRef<ArtistId>>(&mut self, artist_id: ID) -> Result<(), Error> {
+        self.update_artist_and(
+            artist_id,
+            |artist| artist.clear_sort_key(),
+            |collection| Self::sort_artists(collection),
+        )
+    }
+
+    pub fn set_musicbrainz_url<ID: AsRef<ArtistId>, S: AsRef<str>>(
+        &mut self,
+        artist_id: ID,
+        url: S,
+    ) -> Result<(), Error> {
+        let url = url.as_ref().try_into()?;
+        self.update_artist(artist_id, |artist| artist.set_musicbrainz_url(url))
+    }
+
+    pub fn clear_musicbrainz_url<ID: AsRef<ArtistId>>(
+        &mut self,
+        artist_id: ID,
+    ) -> Result<(), Error> {
+        self.update_artist(artist_id, |artist| artist.clear_musicbrainz_url())
+    }
+
+    pub fn add_to_property<ID: AsRef<ArtistId>, S: AsRef<str> + Into<String>>(
+        &mut self,
+        artist_id: ID,
+        property: S,
+        values: Vec<S>,
+    ) -> Result<(), Error> {
+        self.update_artist(artist_id, |artist| artist.add_to_property(property, values))
+    }
+
+    pub fn remove_from_property<ID: AsRef<ArtistId>, S: AsRef<str>>(
+        &mut self,
+        artist_id: ID,
+        property: S,
+        values: Vec<S>,
+    ) -> Result<(), Error> {
+        self.update_artist(artist_id, |artist| {
+            artist.remove_from_property(property, values)
+        })
+    }
+
+    pub fn set_property<ID: AsRef<ArtistId>, S: AsRef<str> + Into<String>>(
+        &mut self,
+        artist_id: ID,
+        property: S,
+        values: Vec<S>,
+    ) -> Result<(), Error> {
+        self.update_artist(artist_id, |artist| artist.set_property(property, values))
+    }
+
+    pub fn clear_property<ID: AsRef<ArtistId>, S: AsRef<str>>(
+        &mut self,
+        artist_id: ID,
+        property: S,
+    ) -> Result<(), Error> {
+        self.update_artist(artist_id, |artist| artist.clear_property(property))
+    }
+}
+
+impl<LIB: ILibrary, DB: IDatabase> MusicHoard<LIB, DB> {
+    /// Create a new [`MusicHoard`] with the provided [`ILibrary`] and [`IDatabase`].
+    pub fn new(library: LIB, database: DB) -> Result<Self, Error> {
+        let mut mh = MusicHoard {
+            collection: vec![],
+            pre_commit: vec![],
+            library,
+            database,
+            library_cache: HashMap::new(),
+            database_cache: vec![],
+        };
+        mh.reload_database()?;
+        Ok(mh)
+    }
 }
 
 #[cfg(test)]
 mod tests {
-    use mockall::predicate;
+    use mockall::{predicate, Sequence};
 
     use crate::core::{
         collection::artist::{ArtistId, MusicBrainz},
@@ -338,28 +405,56 @@ mod tests {
     fn artist_new_delete() {
         let artist_id = ArtistId::new("an artist");
         let artist_id_2 = ArtistId::new("another artist");
-        let mut music_hoard = MusicHoard::default();
 
-        let mut expected: Vec<Artist> = vec![];
+        let collection = FULL_COLLECTION.to_owned();
+        let mut with_artist = collection.clone();
+        with_artist.push(Artist::new(artist_id.clone()));
 
-        music_hoard.add_artist(artist_id.clone());
+        let mut database = MockIDatabase::new();
-        expected.push(Artist::new(artist_id.clone()));
+        let mut seq = Sequence::new();
-        assert_eq!(music_hoard.collection, expected);
+        database
+            .expect_load()
+            .times(1)
+            .times(1)
+            .in_sequence(&mut seq)
+            .returning(|| Ok(FULL_COLLECTION.to_owned()));
+        database
+            .expect_save()
+            .times(1)
+            .in_sequence(&mut seq)
+            .with(predicate::eq(with_artist.clone()))
+            .returning(|_| Ok(()));
+        database
+            .expect_save()
+            .times(1)
+            .in_sequence(&mut seq)
+            .with(predicate::eq(collection.clone()))
+            .returning(|_| Ok(()));
 
-        music_hoard.add_artist(artist_id.clone());
+        let mut music_hoard = MusicHoard::database(database).unwrap();
-        assert_eq!(music_hoard.collection, expected);
+        assert_eq!(music_hoard.collection, collection);
 
-        music_hoard.remove_artist(&artist_id_2);
+        assert!(music_hoard.add_artist(artist_id.clone()).is_ok());
-        assert_eq!(music_hoard.collection, expected);
+        assert_eq!(music_hoard.collection, with_artist);
 
-        music_hoard.remove_artist(&artist_id);
+        assert!(music_hoard.add_artist(artist_id.clone()).is_ok());
-        _ = expected.pop();
+        assert_eq!(music_hoard.collection, with_artist);
-        assert_eq!(music_hoard.collection, expected);
+
+        assert!(music_hoard.remove_artist(&artist_id_2).is_ok());
+        assert_eq!(music_hoard.collection, with_artist);
+
+        assert!(music_hoard.remove_artist(&artist_id).is_ok());
+        assert_eq!(music_hoard.collection, collection);
     }
 
     #[test]
     fn artist_sort_set_clear() {
-        let mut music_hoard = MusicHoard::default();
+        let mut database = MockIDatabase::new();
+        database.expect_load().times(1).returning(|| Ok(vec![]));
+        database.expect_save().times(4).returning(|_| Ok(()));
+
+        type MH = MusicHoard<NoLibrary, MockIDatabase>;
+        let mut music_hoard: MH = MusicHoard::database(database).unwrap();
 
         let artist_1_id = ArtistId::new("the artist");
         let artist_1_sort = ArtistId::new("artist, the");
@@ -370,11 +465,11 @@ mod tests {
         assert!(artist_1_sort < artist_2_id);
         assert!(artist_2_id < artist_1_id);
 
-        music_hoard.add_artist(artist_1_id.clone());
+        assert!(music_hoard.add_artist(artist_1_id.clone()).is_ok());
-        music_hoard.add_artist(artist_2_id.clone());
+        assert!(music_hoard.add_artist(artist_2_id.clone()).is_ok());
 
-        let artist_1: &Artist = music_hoard.get_artist(&artist_1_id).unwrap();
+        let artist_1: &Artist = MH::get_artist(&music_hoard.collection, &artist_1_id).unwrap();
-        let artist_2: &Artist = music_hoard.get_artist(&artist_2_id).unwrap();
+        let artist_2: &Artist = MH::get_artist(&music_hoard.collection, &artist_2_id).unwrap();
 
         assert!(artist_2 < artist_1);
 
@@ -385,8 +480,8 @@ mod tests {
             .set_artist_sort(artist_1_id.as_ref(), artist_1_sort.clone())
             .unwrap();
 
-        let artist_1: &Artist = music_hoard.get_artist(&artist_1_id).unwrap();
+        let artist_1: &Artist = MH::get_artist(&music_hoard.collection, &artist_1_id).unwrap();
-        let artist_2: &Artist = music_hoard.get_artist(&artist_2_id).unwrap();
+        let artist_2: &Artist = MH::get_artist(&music_hoard.collection, &artist_2_id).unwrap();
 
         assert!(artist_1 < artist_2);
 
@@ -395,8 +490,8 @@ mod tests {
 
         music_hoard.clear_artist_sort(artist_1_id.as_ref()).unwrap();
 
-        let artist_1: &Artist = music_hoard.get_artist(&artist_1_id).unwrap();
+        let artist_1: &Artist = MH::get_artist(&music_hoard.collection, &artist_1_id).unwrap();
-        let artist_2: &Artist = music_hoard.get_artist(&artist_2_id).unwrap();
+        let artist_2: &Artist = MH::get_artist(&music_hoard.collection, &artist_2_id).unwrap();
 
         assert!(artist_2 < artist_1);
 
@@ -406,12 +501,16 @@ mod tests {
 
     #[test]
     fn collection_error() {
+        let mut database = MockIDatabase::new();
+        database.expect_load().times(1).returning(|| Ok(vec![]));
+        database.expect_save().times(1).returning(|_| Ok(()));
+
         let artist_id = ArtistId::new("an artist");
-        let mut music_hoard = MusicHoard::default();
+        let mut music_hoard = MusicHoard::database(database).unwrap();
-        music_hoard.add_artist(artist_id.clone());
+        assert!(music_hoard.add_artist(artist_id.clone()).is_ok());
 
         let actual_err = music_hoard
-            .add_musicbrainz_url(&artist_id, MUSICBUTLER)
+            .set_musicbrainz_url(&artist_id, MUSICBUTLER)
             .unwrap_err();
         let expected_err = Error::CollectionError(format!(
             "an error occurred when processing a URL: invalid MusicBrainz URL: {MUSICBUTLER}"
@@ -420,51 +519,17 @@ mod tests {
         assert_eq!(actual_err.to_string(), expected_err.to_string());
     }
 
-    #[test]
-    fn add_remove_musicbrainz_url() {
-        let artist_id = ArtistId::new("an artist");
-        let artist_id_2 = ArtistId::new("another artist");
-        let mut music_hoard = MusicHoard::default();
-
-        music_hoard.add_artist(artist_id.clone());
-
-        let mut expected: Option<MusicBrainz> = None;
-        assert_eq!(music_hoard.collection[0].musicbrainz, expected);
-
-        // Adding URL to an artist not in the collection is an error.
-        assert!(music_hoard
-            .add_musicbrainz_url(&artist_id_2, MUSICBRAINZ)
-            .is_err());
-        assert_eq!(music_hoard.collection[0].musicbrainz, expected);
-
-        // Adding URL to artist.
-        assert!(music_hoard
-            .add_musicbrainz_url(&artist_id, MUSICBRAINZ)
-            .is_ok());
-        _ = expected.insert(MusicBrainz::new(MUSICBRAINZ).unwrap());
-        assert_eq!(music_hoard.collection[0].musicbrainz, expected);
-
-        // Removing a URL from an artist not in the collection is an error.
-        assert!(music_hoard
-            .remove_musicbrainz_url(&artist_id_2, MUSICBRAINZ)
-            .is_err());
-        assert_eq!(music_hoard.collection[0].musicbrainz, expected);
-
-        // Removing a URL in the collection removes it.
-        assert!(music_hoard
-            .remove_musicbrainz_url(&artist_id, MUSICBRAINZ)
-            .is_ok());
-        _ = expected.take();
-        assert_eq!(music_hoard.collection[0].musicbrainz, expected);
-    }
-
     #[test]
     fn set_clear_musicbrainz_url() {
+        let mut database = MockIDatabase::new();
+        database.expect_load().times(1).returning(|| Ok(vec![]));
+        database.expect_save().times(3).returning(|_| Ok(()));
+
         let artist_id = ArtistId::new("an artist");
         let artist_id_2 = ArtistId::new("another artist");
-        let mut music_hoard = MusicHoard::default();
+        let mut music_hoard = MusicHoard::database(database).unwrap();
 
-        music_hoard.add_artist(artist_id.clone());
+        assert!(music_hoard.add_artist(artist_id.clone()).is_ok());
 
         let mut expected: Option<MusicBrainz> = None;
         assert_eq!(music_hoard.collection[0].musicbrainz, expected);
@@ -494,11 +559,15 @@ mod tests {
 
     #[test]
     fn add_to_remove_from_property() {
+        let mut database = MockIDatabase::new();
+        database.expect_load().times(1).returning(|| Ok(vec![]));
+        database.expect_save().times(3).returning(|_| Ok(()));
+
         let artist_id = ArtistId::new("an artist");
         let artist_id_2 = ArtistId::new("another artist");
-        let mut music_hoard = MusicHoard::default();
+        let mut music_hoard = MusicHoard::database(database).unwrap();
 
-        music_hoard.add_artist(artist_id.clone());
+        assert!(music_hoard.add_artist(artist_id.clone()).is_ok());
 
         let mut expected: Vec<String> = vec![];
         assert!(music_hoard.collection[0].properties.is_empty());
@@ -539,11 +608,15 @@ mod tests {
 
     #[test]
     fn set_clear_property() {
+        let mut database = MockIDatabase::new();
+        database.expect_load().times(1).returning(|| Ok(vec![]));
+        database.expect_save().times(3).returning(|_| Ok(()));
+
         let artist_id = ArtistId::new("an artist");
         let artist_id_2 = ArtistId::new("another artist");
-        let mut music_hoard = MusicHoard::default();
+        let mut music_hoard = MusicHoard::database(database).unwrap();
 
-        music_hoard.add_artist(artist_id.clone());
+        assert!(music_hoard.add_artist(artist_id.clone()).is_ok());
 
         let mut expected: Vec<String> = vec![];
         assert!(music_hoard.collection[0].properties.is_empty());
@@ -590,12 +663,12 @@ mod tests {
         expected.sort_unstable();
 
         let mut mh = MusicHoard {
-            collection: right.clone(),
             library_cache: left
                 .clone()
                 .into_iter()
                 .map(|a| (a.id.clone(), a))
                 .collect(),
+            database_cache: right.clone(),
             ..Default::default()
         };
 
@@ -604,12 +677,12 @@ mod tests {
 
         // The merge is completely non-overlapping so it should be commutative.
         let mut mh = MusicHoard {
-            collection: left.clone(),
             library_cache: right
                 .clone()
                 .into_iter()
                 .map(|a| (a.id.clone(), a))
                 .collect(),
+            database_cache: left.clone(),
             ..Default::default()
         };
 
@@ -628,12 +701,12 @@ mod tests {
         expected.sort_unstable();
 
         let mut mh = MusicHoard {
-            collection: right.clone(),
             library_cache: left
                 .clone()
                 .into_iter()
                 .map(|a| (a.id.clone(), a))
                 .collect(),
+            database_cache: right.clone(),
             ..Default::default()
         };
 
@@ -642,12 +715,12 @@ mod tests {
 
         // The merge does not overwrite any data so it should be commutative.
         let mut mh = MusicHoard {
-            collection: left.clone(),
             library_cache: right
                 .clone()
                 .into_iter()
                 .map(|a| (a.id.clone(), a))
                 .collect(),
+            database_cache: left.clone(),
             ..Default::default()
         };
 
@@ -679,12 +752,12 @@ mod tests {
         expected.rotate_right(1);
 
         let mut mh = MusicHoard {
-            collection: right.clone(),
             library_cache: left
                 .clone()
                 .into_iter()
                 .map(|a| (a.id.clone(), a))
                 .collect(),
+            database_cache: right.clone(),
             ..Default::default()
         };
 
@@ -693,12 +766,12 @@ mod tests {
 
         // The merge overwrites the sort data, but no data is erased so it should be commutative.
         let mut mh = MusicHoard {
-            collection: left.clone(),
             library_cache: right
                 .clone()
                 .into_iter()
                 .map(|a| (a.id.clone(), a))
                 .collect(),
+            database_cache: left.clone(),
             ..Default::default()
         };
 
@@ -709,7 +782,6 @@ mod tests {
     #[test]
     fn rescan_library_ordered() {
         let mut library = MockILibrary::new();
-        let database = MockIDatabase::new();
 
         let library_input = Query::new();
         let library_result = Ok(LIBRARY_ITEMS.to_owned());
@@ -720,16 +792,59 @@ mod tests {
             .times(1)
             .return_once(|_| library_result);
 
-        let mut music_hoard = MusicHoard::new(library, database);
+        let mut music_hoard = MusicHoard::library(library);
 
         music_hoard.rescan_library().unwrap();
         assert_eq!(music_hoard.get_collection(), &*LIBRARY_COLLECTION);
     }
 
+    #[test]
+    fn rescan_library_changed() {
+        let mut library = MockILibrary::new();
+        let mut seq = Sequence::new();
+
+        let library_input = Query::new();
+        let library_result = Ok(LIBRARY_ITEMS.to_owned());
+
+        library
+            .expect_list()
+            .with(predicate::eq(library_input))
+            .times(1)
+            .in_sequence(&mut seq)
+            .return_once(|_| library_result);
+
+        let library_input = Query::new();
+        let library_result = Ok(LIBRARY_ITEMS
+            .iter()
+            .filter(|item| item.album_title != "album_title a.a")
+            .cloned()
+            .collect());
+
+        library
+            .expect_list()
+            .with(predicate::eq(library_input))
+            .times(1)
+            .in_sequence(&mut seq)
+            .return_once(|_| library_result);
+
+        let mut music_hoard = MusicHoard::library(library);
+
+        music_hoard.rescan_library().unwrap();
+        assert!(music_hoard.get_collection()[0]
+            .albums
+            .iter()
+            .any(|album| album.id.title == "album_title a.a"));
+
+        music_hoard.rescan_library().unwrap();
+        assert!(!music_hoard.get_collection()[0]
+            .albums
+            .iter()
+            .any(|album| album.id.title == "album_title a.a"));
+    }
+
     #[test]
     fn rescan_library_unordered() {
         let mut library = MockILibrary::new();
-        let database = MockIDatabase::new();
 
         let library_input = Query::new();
         let mut library_result = Ok(LIBRARY_ITEMS.to_owned());
@@ -744,7 +859,7 @@ mod tests {
             .times(1)
             .return_once(|_| library_result);
 
-        let mut music_hoard = MusicHoard::new(library, database);
+        let mut music_hoard = MusicHoard::library(library);
 
         music_hoard.rescan_library().unwrap();
         assert_eq!(music_hoard.get_collection(), &*LIBRARY_COLLECTION);
@@ -753,7 +868,6 @@ mod tests {
     #[test]
     fn rescan_library_album_title_year_clash() {
         let mut library = MockILibrary::new();
-        let database = MockIDatabase::new();
 
         let mut expected = LIBRARY_COLLECTION.to_owned();
         let removed_album_id = expected[0].albums[0].id.clone();
@@ -778,7 +892,7 @@ mod tests {
             .times(1)
             .return_once(|_| library_result);
 
-        let mut music_hoard = MusicHoard::new(library, database);
+        let mut music_hoard = MusicHoard::library(library);
 
         music_hoard.rescan_library().unwrap();
         assert_eq!(music_hoard.get_collection(), &expected);
@@ -787,7 +901,6 @@ mod tests {
     #[test]
     fn rescan_library_album_artist_sort_clash() {
         let mut library = MockILibrary::new();
-        let database = MockIDatabase::new();
 
         let library_input = Query::new();
         let mut library_items = LIBRARY_ITEMS.to_owned();
@@ -811,7 +924,7 @@ mod tests {
             .times(1)
             .return_once(|_| library_result);
 
-        let mut music_hoard = MusicHoard::new(library, database);
+        let mut music_hoard = MusicHoard::library(library);
 
         assert!(music_hoard.rescan_library().is_err());
     }
@@ -826,46 +939,14 @@ mod tests {
             .times(1)
             .return_once(|| Ok(FULL_COLLECTION.to_owned()));
 
-        let mut music_hoard = MusicHoard::new(library, database);
+        let music_hoard = MusicHoard::new(library, database).unwrap();
 
-        music_hoard.load_from_database().unwrap();
         assert_eq!(music_hoard.get_collection(), &*FULL_COLLECTION);
     }
 
-    #[test]
-    fn rescan_get_save() {
-        let mut library = MockILibrary::new();
-        let mut database = MockIDatabase::new();
-
-        let library_input = Query::new();
-        let library_result = Ok(LIBRARY_ITEMS.to_owned());
-
-        let database_input = LIBRARY_COLLECTION.to_owned();
-        let database_result = Ok(());
-
-        library
-            .expect_list()
-            .with(predicate::eq(library_input))
-            .times(1)
-            .return_once(|_| library_result);
-
-        database
-            .expect_save()
-            .with(predicate::eq(database_input))
-            .times(1)
-            .return_once(|_: &Collection| database_result);
-
-        let mut music_hoard = MusicHoard::new(library, database);
-
-        music_hoard.rescan_library().unwrap();
-        assert_eq!(music_hoard.get_collection(), &*LIBRARY_COLLECTION);
-        music_hoard.save_to_database().unwrap();
-    }
-
     #[test]
     fn library_error() {
         let mut library = MockILibrary::new();
-        let database = MockIDatabase::new();
 
         let library_result = Err(library::Error::Invalid(String::from("invalid data")));
 
@@ -874,7 +955,7 @@ mod tests {
             .times(1)
             .return_once(|_| library_result);
 
-        let mut music_hoard = MusicHoard::new(library, database);
+        let mut music_hoard = MusicHoard::library(library);
 
         let actual_err = music_hoard.rescan_library().unwrap_err();
         let expected_err =
@@ -886,7 +967,6 @@ mod tests {
 
     #[test]
     fn database_load_error() {
-        let library = MockILibrary::new();
         let mut database = MockIDatabase::new();
 
         let database_result = Err(database::LoadError::IoError(String::from("I/O error")));
@@ -896,9 +976,7 @@ mod tests {
             .times(1)
             .return_once(|| database_result);
 
-        let mut music_hoard = MusicHoard::new(library, database);
+        let actual_err = MusicHoard::database(database).unwrap_err();
-
-        let actual_err = music_hoard.load_from_database().unwrap_err();
         let expected_err = Error::DatabaseError(
             database::LoadError::IoError(String::from("I/O error")).to_string(),
         );
@@ -909,19 +987,21 @@ mod tests {
 
     #[test]
     fn database_save_error() {
-        let library = MockILibrary::new();
         let mut database = MockIDatabase::new();
 
         let database_result = Err(database::SaveError::IoError(String::from("I/O error")));
 
+        database.expect_load().return_once(|| Ok(vec![]));
         database
             .expect_save()
             .times(1)
             .return_once(|_: &Collection| database_result);
 
-        let mut music_hoard = MusicHoard::new(library, database);
+        let mut music_hoard = MusicHoard::database(database).unwrap();
 
-        let actual_err = music_hoard.save_to_database().unwrap_err();
+        let actual_err = music_hoard
+            .add_artist(ArtistId::new("an artist"))
+            .unwrap_err();
         let expected_err = Error::DatabaseError(
             database::SaveError::IoError(String::from("I/O error")).to_string(),
         );
@@ -929,4 +1009,10 @@ mod tests {
         assert_eq!(actual_err, expected_err);
         assert_eq!(actual_err.to_string(), expected_err.to_string());
     }
+
+    #[test]
+    fn empty() {
+        let music_hoard = MusicHoard::empty();
+        assert!(!format!("{music_hoard:?}").is_empty());
+    }
 }

src/core/musichoard/musichoard_builder.rs

@@ -1,7 +1,10 @@
-use crate::core::{
+use crate::{
-    database::IDatabase,
+    core::{
-    library::ILibrary,
+        database::IDatabase,
-    musichoard::musichoard::{MusicHoard, NoDatabase, NoLibrary},
+        library::ILibrary,
+        musichoard::musichoard::{MusicHoard, NoDatabase, NoLibrary},
+    },
+    Error,
 };
 
 /// Builder for [`MusicHoard`]. Its purpose is to make it easier to set various combinations of
@@ -44,9 +47,32 @@ impl<LIB, DB> MusicHoardBuilder<LIB, DB> {
             database,
         }
     }
+}
 
+impl MusicHoardBuilder<NoLibrary, NoDatabase> {
     /// Build [`MusicHoard`] with the currently set library and database.
-    pub fn build(self) -> MusicHoard<LIB, DB> {
+    pub fn build(self) -> MusicHoard<NoLibrary, NoDatabase> {
+        MusicHoard::empty()
+    }
+}
+
+impl<LIB: ILibrary> MusicHoardBuilder<LIB, NoDatabase> {
+    /// Build [`MusicHoard`] with the currently set library and database.
+    pub fn build(self) -> MusicHoard<LIB, NoDatabase> {
+        MusicHoard::library(self.library)
+    }
+}
+
+impl<DB: IDatabase> MusicHoardBuilder<NoLibrary, DB> {
+    /// Build [`MusicHoard`] with the currently set library and database.
+    pub fn build(self) -> Result<MusicHoard<NoLibrary, DB>, Error> {
+        MusicHoard::database(self.database)
+    }
+}
+
+impl<LIB: ILibrary, DB: IDatabase> MusicHoardBuilder<LIB, DB> {
+    /// Build [`MusicHoard`] with the currently set library and database.
+    pub fn build(self) -> Result<MusicHoard<LIB, DB>, Error> {
         MusicHoard::new(self.library, self.database)
     }
 }
@@ -59,7 +85,7 @@ mod tests {
 
     #[test]
     fn no_library_no_database() {
-        MusicHoardBuilder::default();
+        MusicHoardBuilder::default().build();
     }
 
     #[test]
@@ -74,9 +100,9 @@ mod tests {
     fn no_library_with_database() {
         let mut mh = MusicHoardBuilder::default()
             .set_database(NullDatabase)
-            .build();
+            .build()
-        assert!(mh.load_from_database().is_ok());
+            .unwrap();
-        assert!(mh.save_to_database().is_ok());
+        assert!(mh.reload_database().is_ok());
     }
 
     #[test]
@@ -84,9 +110,9 @@ mod tests {
         let mut mh = MusicHoardBuilder::default()
             .set_library(NullLibrary)
             .set_database(NullDatabase)
-            .build();
+            .build()
+            .unwrap();
         assert!(mh.rescan_library().is_ok());
-        assert!(mh.load_from_database().is_ok());
+        assert!(mh.reload_database().is_ok());
-        assert!(mh.save_to_database().is_ok());
     }
 }

src/main.rs

@@ -61,7 +61,7 @@ struct DbOpt {
 }
 
 fn with<LIB: ILibrary, DB: IDatabase>(builder: MusicHoardBuilder<LIB, DB>) {
-    let music_hoard = builder.build();
+    let music_hoard = builder.build().expect("failed to initialise MusicHoard");
 
     // Initialize the terminal user interface.
     let backend = CrosstermBackend::new(io::stdout());

src/tui/app/machine/browse.rs

@@ -36,14 +36,9 @@ impl<'a, MH: IMusicHoard> From<&'a mut AppMachine<MH, AppBrowse>> for AppPublic<
 impl<MH: IMusicHoard> IAppInteractBrowse for AppMachine<MH, AppBrowse> {
     type APP = App<MH>;
 
-    fn save_and_quit(mut self) -> Self::APP {
+    fn quit(mut self) -> Self::APP {
-        match self.inner.music_hoard.save_to_database() {
+        self.inner.running = false;
-            Ok(_) => {
+        self.into()
-                self.inner.running = false;
-                self.into()
-            }
-            Err(err) => AppMachine::error(self.inner, err.to_string()).into(),
-        }
     }
 
     fn increment_category(mut self) -> Self::APP {
@@ -104,37 +99,16 @@ mod tests {
     use super::*;
 
     #[test]
-    fn save_and_quit() {
+    fn quit() {
-        let mut music_hoard = music_hoard(vec![]);
+        let music_hoard = music_hoard(vec![]);
-
-        music_hoard
-            .expect_save_to_database()
-            .times(1)
-            .return_once(|| Ok(()));
 
         let browse = AppMachine::browse(inner(music_hoard));
 
-        let app = browse.save_and_quit();
+        let app = browse.quit();
         assert!(!app.is_running());
         app.unwrap_browse();
     }
 
-    #[test]
-    fn save_and_quit_error() {
-        let mut music_hoard = music_hoard(vec![]);
-
-        music_hoard
-            .expect_save_to_database()
-            .times(1)
-            .return_once(|| Err(musichoard::Error::DatabaseError(String::from("get rekt"))));
-
-        let browse = AppMachine::browse(inner(music_hoard));
-
-        let app = browse.save_and_quit();
-        assert!(app.is_running());
-        app.unwrap_error();
-    }
-
     #[test]
     fn increment_decrement() {
         let mut browse = AppMachine::browse(inner(music_hoard(COLLECTION.to_owned())));

src/tui/app/machine/mod.rs

@@ -48,7 +48,6 @@ impl<MH: IMusicHoard> App<MH> {
     }
 
     fn init(music_hoard: &mut MH) -> Result<(), musichoard::Error> {
-        music_hoard.load_from_database()?;
         music_hoard.rescan_library()?;
         Ok(())
     }
@@ -196,10 +195,6 @@ mod tests {
     fn music_hoard_init(collection: Collection) -> MockIMusicHoard {
         let mut music_hoard = music_hoard(collection);
 
-        music_hoard
-            .expect_load_from_database()
-            .times(1)
-            .return_once(|| Ok(()));
         music_hoard
             .expect_rescan_library()
             .times(1)
@@ -323,9 +318,9 @@ mod tests {
         let mut music_hoard = MockIMusicHoard::new();
 
         music_hoard
-            .expect_load_from_database()
+            .expect_rescan_library()
             .times(1)
-            .return_once(|| Err(musichoard::Error::DatabaseError(String::from("get rekt"))));
+            .return_once(|| Err(musichoard::Error::LibraryError(String::from("get rekt"))));
         music_hoard.expect_get_collection().return_const(vec![]);
 
         let app = App::new(music_hoard);

src/tui/app/machine/reload.rs

@@ -49,7 +49,7 @@ impl<MH: IMusicHoard> IAppInteractReload for AppMachine<MH, AppReload> {
             self.inner.music_hoard.get_collection(),
             &self.inner.selection,
         );
-        let result = self.inner.music_hoard.load_from_database();
+        let result = self.inner.music_hoard.reload_database();
         self.refresh(previous, result)
     }
 
@@ -98,7 +98,7 @@ mod tests {
         let mut music_hoard = music_hoard(vec![]);
 
         music_hoard
-            .expect_load_from_database()
+            .expect_reload_database()
             .times(1)
             .return_once(|| Ok(()));
 
@@ -126,7 +126,7 @@ mod tests {
         let mut music_hoard = music_hoard(vec![]);
 
         music_hoard
-            .expect_load_from_database()
+            .expect_reload_database()
             .times(1)
             .return_once(|| Err(musichoard::Error::DatabaseError(String::from("get rekt"))));
 

src/tui/app/mod.rs

@@ -33,7 +33,7 @@ pub trait IAppInteract {
 pub trait IAppInteractBrowse {
     type APP: IAppInteract;
 
-    fn save_and_quit(self) -> Self::APP;
+    fn quit(self) -> Self::APP;
 
     fn increment_category(self) -> Self::APP;
     fn decrement_category(self) -> Self::APP;

src/tui/handler.rs

@@ -83,7 +83,7 @@ impl<APP: IAppInteract> IEventHandlerPrivate<APP> for EventHandler {
     fn handle_browse_key_event(app: <APP as IAppInteract>::BS, key_event: KeyEvent) -> APP {
         match key_event.code {
             // Exit application on `ESC` or `q`.
-            KeyCode::Esc | KeyCode::Char('q') | KeyCode::Char('Q') => app.save_and_quit(),
+            KeyCode::Esc | KeyCode::Char('q') | KeyCode::Char('Q') => app.quit(),
             // Category change.
             KeyCode::Left => app.decrement_category(),
             KeyCode::Right => app.increment_category(),

src/tui/lib.rs

@@ -6,8 +6,7 @@ use mockall::automock;
 #[cfg_attr(test, automock)]
 pub trait IMusicHoard {
     fn rescan_library(&mut self) -> Result<(), musichoard::Error>;
-    fn load_from_database(&mut self) -> Result<(), musichoard::Error>;
+    fn reload_database(&mut self) -> Result<(), musichoard::Error>;
-    fn save_to_database(&mut self) -> Result<(), musichoard::Error>;
     fn get_collection(&self) -> &Collection;
 }
 
@@ -17,12 +16,8 @@ impl<LIB: ILibrary, DB: IDatabase> IMusicHoard for MusicHoard<LIB, DB> {
         MusicHoard::rescan_library(self)
     }
 
-    fn load_from_database(&mut self) -> Result<(), musichoard::Error> {
+    fn reload_database(&mut self) -> Result<(), musichoard::Error> {
-        MusicHoard::load_from_database(self)
+        MusicHoard::reload_database(self)
-    }
-
-    fn save_to_database(&mut self) -> Result<(), musichoard::Error> {
-        MusicHoard::save_to_database(self)
     }
 
     fn get_collection(&self) -> &Collection {

src/tui/mod.rs

@@ -193,7 +193,7 @@ mod tests {
     fn music_hoard(collection: Collection) -> MockIMusicHoard {
         let mut music_hoard = MockIMusicHoard::new();
 
-        music_hoard.expect_load_from_database().returning(|| Ok(()));
+        music_hoard.expect_reload_database().returning(|| Ok(()));
         music_hoard.expect_rescan_library().returning(|| Ok(()));
         music_hoard.expect_get_collection().return_const(collection);
 

tests/lib.rs

@@ -29,10 +29,10 @@ fn merge_library_then_database() {
     let backend = JsonDatabaseFileBackend::new(&*database::json::DATABASE_TEST_FILE);
     let database = JsonDatabase::new(backend);
 
-    let mut music_hoard = MusicHoard::new(library, database);
+    let mut music_hoard = MusicHoard::new(library, database).unwrap();
 
     music_hoard.rescan_library().unwrap();
-    music_hoard.load_from_database().unwrap();
+    music_hoard.reload_database().unwrap();
 
     assert_eq!(music_hoard.get_collection(), &*COLLECTION);
 }
@@ -52,9 +52,9 @@ fn merge_database_then_library() {
     let backend = JsonDatabaseFileBackend::new(&*database::json::DATABASE_TEST_FILE);
     let database = JsonDatabase::new(backend);
 
-    let mut music_hoard = MusicHoard::new(library, database);
+    let mut music_hoard = MusicHoard::new(library, database).unwrap();
 
-    music_hoard.load_from_database().unwrap();
+    music_hoard.reload_database().unwrap();
     music_hoard.rescan_library().unwrap();
 
     assert_eq!(music_hoard.get_collection(), &*COLLECTION);