Reduce code repetition

src/lib.rs

@@ -542,6 +542,10 @@ impl<LIB: ILibrary, DB: IDatabase> MusicHoard<LIB, DB> {
         }
     }
 
+    pub fn get_collection(&self) -> &Collection {
+        &self.collection
+    }
+
     pub fn rescan_library(&mut self) -> Result<(), Error> {
         match self.library {
             Some(ref mut library) => {
@@ -584,8 +588,73 @@ impl<LIB: ILibrary, DB: IDatabase> MusicHoard<LIB, DB> {
         }
     }
 
-    pub fn get_collection(&self) -> &Collection {
+    pub fn new_artist<ID: AsRef<ArtistId>>(&mut self, artist_id: ID) -> Result<(), Error> {
-        &self.collection
+        if let Ok(artist) = self.get_artist_or_err(artist_id.as_ref()) {
+            return Err(Error::CollectionError(format!(
+                "artist '{}' is already in the collection",
+                artist.id
+            )));
+        }
+
+        let new_artist = vec![Artist::new(artist_id.as_ref().clone())];
+
+        let collection = mem::take(&mut self.collection);
+        self.collection = Self::merge(collection, new_artist);
+
+        Ok(())
+    }
+
+    pub fn delete_artist<ID: AsRef<ArtistId>>(&mut self, artist_id: ID) -> Result<(), Error> {
+        let index_opt = self
+            .collection
+            .iter()
+            .position(|a| &a.id == artist_id.as_ref());
+
+        match index_opt {
+            Some(index) => {
+                self.collection.remove(index);
+                Ok(())
+            }
+            None => Err(Error::CollectionError(format!(
+                "artist '{}' is not in the collection",
+                artist_id.as_ref()
+            ))),
+        }
+    }
+
+    pub fn add_musicbrainz_url<ID: AsRef<ArtistId>, S: AsRef<str>>(
+        &mut self,
+        artist_id: ID,
+        url: S,
+    ) -> Result<(), Error> {
+        self.get_artist_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> {
+        self.get_artist_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> {
+        self.get_artist_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_or_err(artist_id.as_ref())?
+            .clear_musicbrainz_url()
     }
 
     fn sort(collection: &mut [Artist]) {
@@ -669,94 +738,11 @@ impl<LIB: ILibrary, DB: IDatabase> MusicHoard<LIB, DB> {
         artists
     }
 
-    pub fn new_artist(&mut self, artist_id: ArtistId) -> Result<(), Error> {
+    fn get_artist_or_err(&mut self, artist_id: &ArtistId) -> Result<&mut Artist, Error> {
-        // We want to return an error if the artist already exists so we first do a check.
+        let artist_opt = self.collection.iter_mut().find(|a| &a.id == artist_id);
-        let artists: &Vec<Artist> = &self.collection;
+        artist_opt.ok_or_else(|| {
-
+            Error::CollectionError(format!("artist '{}' is not in the collection", artist_id))
-        if let Some(ref a) = artists.iter().find(|a| a.id == artist_id) {
+        })
-            return Err(Error::CollectionError(format!(
-                "artist '{}' is already in the collection",
-                a.id
-            )));
-        }
-
-        let new_artist = vec![Artist::new(artist_id)];
-
-        let collection = mem::take(&mut self.collection);
-        self.collection = Self::merge(collection, new_artist);
-
-        Ok(())
-    }
-
-    pub fn delete_artist(&mut self, artist_id: ArtistId) -> Result<(), Error> {
-        let index_opt = self.collection.iter().position(|a| a.id == artist_id);
-
-        match index_opt {
-            Some(index) => {
-                self.collection.remove(index);
-                Ok(())
-            }
-            None => Err(Error::CollectionError(format!(
-                "artist '{}' is not in the collection",
-                artist_id
-            ))),
-        }
-    }
-
-    pub fn add_musicbrainz_url<S: AsRef<str>>(
-        &mut self,
-        artist_id: ArtistId,
-        url: S,
-    ) -> Result<(), Error> {
-        let mut artist_opt = self.collection.iter_mut().find(|a| a.id == artist_id);
-        match artist_opt {
-            Some(ref mut artist) => artist.add_musicbrainz_url(url),
-            None => Err(Error::CollectionError(format!(
-                "artist '{}' is not in the collection",
-                artist_id
-            ))),
-        }
-    }
-
-    pub fn remove_musicbrainz_url<S: AsRef<str>>(
-        &mut self,
-        artist_id: ArtistId,
-        url: S,
-    ) -> Result<(), Error> {
-        let mut artist_opt = self.collection.iter_mut().find(|a| a.id == artist_id);
-        match artist_opt {
-            Some(ref mut artist) => artist.remove_musicbrainz_url(url),
-            None => Err(Error::CollectionError(format!(
-                "artist '{}' is not in the collection",
-                artist_id
-            ))),
-        }
-    }
-
-    pub fn set_musicbrainz_url<S: AsRef<str>>(
-        &mut self,
-        artist_id: ArtistId,
-        url: S,
-    ) -> Result<(), Error> {
-        let mut artist_opt = self.collection.iter_mut().find(|a| a.id == artist_id);
-        match artist_opt {
-            Some(ref mut artist) => artist.set_musicbrainz_url(url),
-            None => Err(Error::CollectionError(format!(
-                "artist '{}' is not in the collection",
-                artist_id
-            ))),
-        }
-    }
-
-    pub fn clear_musicbrainz_url(&mut self, artist_id: ArtistId) -> Result<(), Error> {
-        let mut artist_opt = self.collection.iter_mut().find(|a| a.id == artist_id);
-        match artist_opt {
-            Some(ref mut artist) => artist.clear_musicbrainz_url(),
-            None => Err(Error::CollectionError(format!(
-                "artist '{}' is not in the collection",
-                artist_id
-            ))),
-        }
     }
 }