Enable running without library or database

src/bin/musichoard-edit.rs

@@ -16,7 +16,7 @@ type MH = MusicHoard<NoLibrary, JsonDatabase<JsonDatabaseFileBackend>>;
 struct Opt {
     #[structopt(
         long = "database",
-        name = "database file path",
+        help = "Database file path",
         default_value = "database.json"
     )]
     database_file_path: PathBuf,

src/lib.rs

@@ -788,45 +788,34 @@ impl<LIB: ILibrary, DB: IDatabase> MusicHoard<LIB, DB> {
     }
 
     pub fn rescan_library(&mut self) -> Result<(), Error> {
-        match self.library {
-            Some(ref mut library) => {
-                let items = library.list(&Query::new())?;
-                let mut library_collection = Self::items_to_artists(items);
-                Self::sort(&mut library_collection);
+        if let Some(ref mut library) = self.library {
+            let items = library.list(&Query::new())?;
+            let mut library_collection = Self::items_to_artists(items);
+            Self::sort(&mut library_collection);
 
-                let collection = mem::take(&mut self.collection);
-                self.collection = Self::merge(library_collection, collection);
-
-                Ok(())
-            }
-            None => Err(Error::LibraryError(String::from("library not provided"))),
+            let collection = mem::take(&mut self.collection);
+            self.collection = Self::merge(library_collection, collection);
         }
+        Ok(())
     }
 
     pub fn load_from_database(&mut self) -> Result<(), Error> {
-        match self.database {
-            Some(ref mut database) => {
-                let mut database_collection: Collection = vec![];
-                database.load(&mut database_collection)?;
-                Self::sort(&mut database_collection);
+        if let Some(ref mut database) = self.database {
+            let mut database_collection: Collection = vec![];
+            database.load(&mut database_collection)?;
+            Self::sort(&mut database_collection);
 
-                let collection = mem::take(&mut self.collection);
-                self.collection = Self::merge(collection, database_collection);
-
-                Ok(())
-            }
-            None => Err(Error::DatabaseError(String::from("database not provided"))),
+            let collection = mem::take(&mut self.collection);
+            self.collection = Self::merge(collection, database_collection);
         }
+        Ok(())
     }
 
     pub fn save_to_database(&mut self) -> Result<(), Error> {
-        match self.database {
-            Some(ref mut database) => {
-                database.save(&self.collection)?;
-                Ok(())
-            }
-            None => Err(Error::DatabaseError(String::from("database not provided"))),
+        if let Some(ref mut database) = self.database {
+            database.save(&self.collection)?;
         }
+        Ok(())
     }
 
     pub fn add_artist<ID: Into<ArtistId>>(&mut self, artist_id: ID) {
@@ -1963,10 +1952,7 @@ mod tests {
         let database = Some(MockIDatabase::new());
         let mut music_hoard = MusicHoard::new(library, database);
 
-        let actual_err = music_hoard.rescan_library().unwrap_err();
-        let expected_err = Error::LibraryError(String::from("library not provided"));
-
-        assert_eq!(actual_err, expected_err);
+        assert!(music_hoard.rescan_library().is_ok());
     }
 
     #[test]
@@ -1997,15 +1983,8 @@ mod tests {
         let database: Option<NoDatabase> = None;
         let mut music_hoard = MusicHoard::new(library, database);
 
-        let expected_err = Error::DatabaseError(String::from("database not provided"));
-
-        let actual_err = music_hoard.load_from_database().unwrap_err();
-        assert_eq!(actual_err, expected_err);
-        assert_eq!(actual_err.to_string(), expected_err.to_string());
-
-        let actual_err = music_hoard.save_to_database().unwrap_err();
-        assert_eq!(actual_err, expected_err);
-        assert_eq!(actual_err.to_string(), expected_err.to_string());
+        assert!(music_hoard.load_from_database().is_ok());
+        assert!(music_hoard.save_to_database().is_ok());
     }
 
     #[test]

src/main.rs

@@ -3,6 +3,7 @@ use std::path::PathBuf;
 use std::{ffi::OsString, io};
 
 use musichoard::Collection;
+use musichoard::library::NoLibrary;
 use ratatui::{backend::CrosstermBackend, Terminal};
 use structopt::StructOpt;
 
@@ -27,22 +28,28 @@ use tui::{event::EventChannel, handler::EventHandler, listener::EventListener, T
 
 #[derive(StructOpt)]
 struct Opt {
-    #[structopt(long = "ssh", name = "beets SSH URI")]
+    #[structopt(long = "ssh", help = "Beets SSH URI")]
     beets_ssh_uri: Option<OsString>,
 
-    #[structopt(long = "beets", name = "beets config file path")]
+    #[structopt(long = "beets", help = "Beets config file path")]
     beets_config_file_path: Option<OsString>,
 
+    #[structopt(long = "no-library", help = "Do not connect to the library")]
+    no_library: bool,
+
     #[structopt(
         long = "database",
-        name = "database file path",
+        help = "Database file path",
         default_value = "database.json"
     )]
     database_file_path: PathBuf,
+
+    #[structopt(long = "no-database", help = "Do not read from/write to the database")]
+    no_database: bool,
 }
 
-fn with<LIB: ILibrary, DB: IDatabase>(lib: LIB, db: DB) {
-    let music_hoard = MusicHoard::new(Some(lib), Some(db));
+fn with<LIB: ILibrary, DB: IDatabase>(lib: Option<LIB>, db: Option<DB>) {
+    let music_hoard = MusicHoard::new(lib, db);
 
     // Initialize the terminal user interface.
     let backend = CrosstermBackend::new(io::stdout());
@@ -61,27 +68,34 @@ fn with<LIB: ILibrary, DB: IDatabase>(lib: LIB, db: DB) {
 fn main() {
     let opt = Opt::from_args();
 
-    // Create an empty database file if it does not exist.
-    match OpenOptions::new()
-        .write(true)
-        .create_new(true)
-        .open(&opt.database_file_path)
-    {
-        Ok(f) => {
-            drop(f);
-            JsonDatabase::new(JsonDatabaseFileBackend::new(&opt.database_file_path))
-                .save::<Collection>(&vec![])
-                .expect("failed to create empty database");
+    let db = if opt.no_database {
+        None
+    } else {
+        // Create an empty database file if it does not exist.
+        match OpenOptions::new()
+            .write(true)
+            .create_new(true)
+            .open(&opt.database_file_path)
+        {
+            Ok(f) => {
+                drop(f);
+                JsonDatabase::new(JsonDatabaseFileBackend::new(&opt.database_file_path))
+                    .save::<Collection>(&vec![])
+                    .expect("failed to create empty database");
+            }
+            Err(e) => match e.kind() {
+                io::ErrorKind::AlreadyExists => {}
+                _ => panic!("failed to access database file"),
+            },
         }
-        Err(e) => match e.kind() {
-            io::ErrorKind::AlreadyExists => {}
-            _ => panic!("failed to access database file"),
-        },
-    }
 
-    // Create the application.
-    let db_exec = JsonDatabaseFileBackend::new(&opt.database_file_path);
-    if let Some(uri) = opt.beets_ssh_uri {
+        let db_exec = JsonDatabaseFileBackend::new(&opt.database_file_path);
+        Some(JsonDatabase::new(db_exec))
+    };
+
+    if opt.no_library {
+        with(None::<NoLibrary>, db);
+    } else if let Some(uri) = opt.beets_ssh_uri {
         let uri = uri.into_string().expect("invalid SSH URI");
         let beets_config_file_path = opt
             .beets_config_file_path
@@ -91,10 +105,10 @@ fn main() {
         let lib_exec = BeetsLibrarySshExecutor::new(uri)
             .expect("failed to initialise beets")
             .config(beets_config_file_path);
-        with(BeetsLibrary::new(lib_exec), JsonDatabase::new(db_exec));
+        with(Some(BeetsLibrary::new(lib_exec)), db);
     } else {
         let lib_exec = BeetsLibraryProcessExecutor::default().config(opt.beets_config_file_path);
-        with(BeetsLibrary::new(lib_exec), JsonDatabase::new(db_exec));
+        with(Some(BeetsLibrary::new(lib_exec)), db);
     }
 }