Integrate changes with binary

.gitignore

@@ -1,2 +1,3 @@
 /target
 /codecov
+database.json

src/database/json/mod.rs

@@ -6,13 +6,19 @@ use serde::Serialize;
 #[cfg(test)]
 use mockall::automock;
 
-use super::{Error, IDatabase};
+use super::{IDatabase, ReadError, WriteError};
 
 pub mod backend;
 
-impl From<serde_json::Error> for Error {
-    fn from(err: serde_json::Error) -> Error {
-        Error::SerDeError(err.to_string())
+impl From<serde_json::Error> for ReadError {
+    fn from(err: serde_json::Error) -> ReadError {
+        ReadError::SerDeError(err.to_string())
+    }
+}
+
+impl From<serde_json::Error> for WriteError {
+    fn from(err: serde_json::Error) -> WriteError {
+        WriteError::SerDeError(err.to_string())
     }
 }
 
@@ -40,13 +46,13 @@ impl<JDB: IJsonDatabaseBackend> JsonDatabase<JDB> {
 }
 
 impl<JDB: IJsonDatabaseBackend> IDatabase for JsonDatabase<JDB> {
-    fn read<D: DeserializeOwned>(&self, collection: &mut D) -> Result<(), Error> {
+    fn read<D: DeserializeOwned>(&self, collection: &mut D) -> Result<(), ReadError> {
         let serialized = self.backend.read()?;
         *collection = serde_json::from_str(&serialized)?;
         Ok(())
     }
 
-    fn write<S: Serialize>(&mut self, collection: &S) -> Result<(), Error> {
+    fn write<S: Serialize>(&mut self, collection: &S) -> Result<(), WriteError> {
         let serialized = serde_json::to_string(&collection)?;
         self.backend.write(&serialized)?;
         Ok(())
@@ -191,7 +197,7 @@ mod tests {
         let serde_err = serde_json::to_string(&object);
         assert!(serde_err.is_err());
 
-        let serde_err: Error = serde_err.unwrap_err().into();
+        let serde_err: WriteError = serde_err.unwrap_err().into();
         assert!(!serde_err.to_string().is_empty());
         assert!(!format!("{:?}", serde_err).is_empty());
     }

src/database/mod.rs

@@ -14,35 +14,61 @@ pub mod json;
 #[cfg_attr(test, automock)]
 pub trait IDatabase {
     /// Read collection from the database.
-    fn read<D: DeserializeOwned + 'static>(&self, collection: &mut D) -> Result<(), Error>;
+    fn read<D: DeserializeOwned + 'static>(&self, collection: &mut D) -> Result<(), ReadError>;
 
     /// Write collection to the database.
-    fn write<S: Serialize + 'static>(&mut self, collection: &S) -> Result<(), Error>;
+    fn write<S: Serialize + 'static>(&mut self, collection: &S) -> Result<(), WriteError>;
 }
 
 /// Error type for database calls.
 #[derive(Debug)]
-pub enum Error {
-    /// The database experienced an I/O error.
+pub enum ReadError {
+    /// The database experienced an I/O read error.
     IoError(String),
-    /// The database experienced a (de)serialisation error.
+    /// The database experienced a deserialisation error.
     SerDeError(String),
 }
 
-impl fmt::Display for Error {
+impl fmt::Display for ReadError {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match *self {
-            Self::IoError(ref s) => write!(f, "the database experienced an I/O error: {s}"),
+            Self::IoError(ref s) => write!(f, "the database experienced an I/O read error: {s}"),
             Self::SerDeError(ref s) => {
-                write!(f, "the database experienced a (de)serialisation error: {s}")
+                write!(f, "the database experienced a deserialisation error: {s}")
             }
         }
     }
 }
 
-impl From<std::io::Error> for Error {
-    fn from(err: std::io::Error) -> Error {
-        Error::IoError(err.to_string())
+impl From<std::io::Error> for ReadError {
+    fn from(err: std::io::Error) -> ReadError {
+        ReadError::IoError(err.to_string())
+    }
+}
+
+/// Error type for database calls.
+#[derive(Debug)]
+pub enum WriteError {
+    /// The database experienced an I/O write error.
+    IoError(String),
+    /// The database experienced a serialisation error.
+    SerDeError(String),
+}
+
+impl fmt::Display for WriteError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            Self::IoError(ref s) => write!(f, "the database experienced an I/O write error: {s}"),
+            Self::SerDeError(ref s) => {
+                write!(f, "the database experienced a serialisation error: {s}")
+            }
+        }
+    }
+}
+
+impl From<std::io::Error> for WriteError {
+    fn from(err: std::io::Error) -> WriteError {
+        WriteError::IoError(err.to_string())
     }
 }
 
@@ -50,11 +76,15 @@ impl From<std::io::Error> for Error {
 mod tests {
     use std::io;
 
-    use super::Error;
+    use super::{ReadError, WriteError};
 
     #[test]
     fn errors() {
-        let io_err: Error = io::Error::new(io::ErrorKind::Interrupted, "error").into();
+        let io_err: ReadError = io::Error::new(io::ErrorKind::Interrupted, "error").into();
+        assert!(!io_err.to_string().is_empty());
+        assert!(!format!("{:?}", io_err).is_empty());
+
+        let io_err: WriteError = io::Error::new(io::ErrorKind::Interrupted, "error").into();
         assert!(!io_err.to_string().is_empty());
         assert!(!format!("{:?}", io_err).is_empty());
     }

src/lib.rs

@@ -7,7 +7,8 @@ use std::{
     cmp::Ordering,
     collections::{HashMap, HashSet},
     fmt,
-    iter::Peekable, mem,
+    iter::Peekable,
+    mem,
 };
 
 use database::IDatabase;
@@ -212,8 +213,14 @@ impl From<library::Error> for Error {
     }
 }
 
-impl From<database::Error> for Error {
-    fn from(err: database::Error) -> Error {
+impl From<database::ReadError> for Error {
+    fn from(err: database::ReadError) -> Error {
+        Error::DatabaseError(err.to_string())
+    }
+}
+
+impl From<database::WriteError> for Error {
+    fn from(err: database::WriteError) -> Error {
         Error::DatabaseError(err.to_string())
     }
 }
@@ -521,7 +528,7 @@ mod tests {
         let library = MockILibrary::new();
         let mut database = MockIDatabase::new();
 
-        let database_result = Err(database::Error::IoError(String::from("I/O error")));
+        let database_result = Err(database::WriteError::IoError(String::from("I/O error")));
 
         database
             .expect_write()
@@ -531,8 +538,9 @@ mod tests {
         let mut music_hoard = MusicHoard::new(library, database);
 
         let actual_err = music_hoard.save_to_database().unwrap_err();
-        let expected_err =
-            Error::DatabaseError(database::Error::IoError(String::from("I/O error")).to_string());
+        let expected_err = Error::DatabaseError(
+            database::WriteError::IoError(String::from("I/O error")).to_string(),
+        );
 
         assert_eq!(actual_err, expected_err);
         assert_eq!(actual_err.to_string(), expected_err.to_string());

src/main.rs

@@ -1,6 +1,8 @@
+use std::fs::OpenOptions;
 use std::path::PathBuf;
 use std::{ffi::OsString, io};
 
+use musichoard::Collection;
 use ratatui::{backend::CrosstermBackend, Terminal};
 use structopt::StructOpt;
 
@@ -57,9 +59,28 @@ fn with<LIB: ILibrary, DB: IDatabase>(lib: LIB, db: DB) {
 }
 
 fn main() {
-    // Create the application.
     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))
+                .write::<Collection>(&vec![])
+                .expect("failed to create empty database");
+        }
+        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 uri = uri.into_string().expect("invalid SSH URI");
         let beets_config_file_path = opt
@@ -70,11 +91,9 @@ fn main() {
         let lib_exec = BeetsLibrarySshExecutor::new(uri)
             .expect("failed to initialise beets")
             .config(beets_config_file_path);
-        let db_exec = JsonDatabaseFileBackend::new(&opt.database_file_path);
         with(BeetsLibrary::new(lib_exec), JsonDatabase::new(db_exec));
     } else {
         let lib_exec = BeetsLibraryProcessExecutor::default().config(opt.beets_config_file_path);
-        let db_exec = JsonDatabaseFileBackend::new(&opt.database_file_path);
         with(BeetsLibrary::new(lib_exec), JsonDatabase::new(db_exec));
     }
 }

src/tui/event.rs

@@ -2,11 +2,14 @@ use crossterm::event::{KeyEvent, MouseEvent};
 use std::fmt;
 use std::sync::mpsc;
 
+use super::ui::UiError;
+
 #[derive(Debug)]
 pub enum EventError {
     Send(Event),
     Recv,
     Io(std::io::Error),
+    Ui(String),
 }
 
 impl fmt::Display for EventError {
@@ -17,6 +20,9 @@ impl fmt::Display for EventError {
             Self::Io(ref e) => {
                 write!(f, "an I/O error was triggered during event handling: {e}")
             }
+            Self::Ui(ref s) => {
+                write!(f, "the UI returned an error during event handling: {s}")
+            }
         }
     }
 }
@@ -33,6 +39,12 @@ impl From<mpsc::RecvError> for EventError {
     }
 }
 
+impl From<UiError> for EventError {
+    fn from(err: UiError) -> EventError {
+        EventError::Ui(err.to_string())
+    }
+}
+
 #[derive(Clone, Copy, Debug)]
 pub enum Event {
     Key(KeyEvent),

src/tui/handler.rs

@@ -14,7 +14,8 @@ pub trait IEventHandler<UI> {
 }
 
 trait IEventHandlerPrivate<UI> {
-    fn handle_key_event(ui: &mut UI, key_event: KeyEvent);
+    fn handle_key_event(ui: &mut UI, key_event: KeyEvent) -> Result<(), EventError>;
+    fn quit(ui: &mut UI) -> Result<(), EventError>;
 }
 
 pub struct EventHandler {
@@ -31,7 +32,7 @@ impl EventHandler {
 impl<UI: IUi> IEventHandler<UI> for EventHandler {
     fn handle_next_event(&self, ui: &mut UI) -> Result<(), EventError> {
         match self.events.recv()? {
-            Event::Key(key_event) => Self::handle_key_event(ui, key_event),
+            Event::Key(key_event) => Self::handle_key_event(ui, key_event)?,
             Event::Mouse(_) => {}
             Event::Resize(_, _) => {}
         };
@@ -40,16 +41,16 @@ impl<UI: IUi> IEventHandler<UI> for EventHandler {
 }
 
 impl<UI: IUi> IEventHandlerPrivate<UI> for EventHandler {
-    fn handle_key_event(ui: &mut UI, key_event: KeyEvent) {
+    fn handle_key_event(ui: &mut UI, key_event: KeyEvent) -> Result<(), EventError> {
         match key_event.code {
             // Exit application on `ESC` or `q`.
             KeyCode::Esc | KeyCode::Char('q') => {
-                ui.quit();
+                Self::quit(ui)?;
             }
             // Exit application on `Ctrl-C`.
             KeyCode::Char('c') | KeyCode::Char('C') => {
                 if key_event.modifiers == KeyModifiers::CONTROL {
-                    ui.quit();
+                    Self::quit(ui)?;
                 }
             }
             // Category change.
@@ -69,6 +70,14 @@ impl<UI: IUi> IEventHandlerPrivate<UI> for EventHandler {
             // Other keys.
             _ => {}
         }
+
+        Ok(())
+    }
+
+    fn quit(ui: &mut UI) -> Result<(), EventError> {
+        ui.quit();
+        ui.save()?;
+        Ok(())
     }
 }
 // GRCOV_EXCL_STOP

src/tui/lib.rs

@@ -3,24 +3,26 @@ use musichoard::{database::IDatabase, library::ILibrary, Collection, MusicHoard}
 #[cfg(test)]
 use mockall::automock;
 
-use super::Error;
-
 #[cfg_attr(test, automock)]
 pub trait IMusicHoard {
-    fn rescan_library(&mut self) -> Result<(), Error>;
+    fn rescan_library(&mut self) -> Result<(), musichoard::Error>;
+    fn load_from_database(&mut self) -> Result<(), musichoard::Error>;
+    fn save_to_database(&mut self) -> Result<(), musichoard::Error>;
     fn get_collection(&self) -> &Collection;
 }
 
-impl From<musichoard::Error> for Error {
-    fn from(err: musichoard::Error) -> Error {
-        Error::Lib(err.to_string())
-    }
-}
-
 // GRCOV_EXCL_START
 impl<LIB: ILibrary, DB: IDatabase> IMusicHoard for MusicHoard<LIB, DB> {
-    fn rescan_library(&mut self) -> Result<(), Error> {
-        Ok(MusicHoard::rescan_library(self)?)
+    fn rescan_library(&mut self) -> Result<(), musichoard::Error> {
+        MusicHoard::rescan_library(self)
+    }
+
+    fn load_from_database(&mut self) -> Result<(), musichoard::Error> {
+        MusicHoard::load_from_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

@@ -25,6 +25,12 @@ pub enum Error {
     ListenerPanic,
 }
 
+impl From<musichoard::Error> for Error {
+    fn from(err: musichoard::Error) -> Error {
+        Error::Lib(err.to_string())
+    }
+}
+
 impl From<io::Error> for Error {
     fn from(err: io::Error) -> Error {
         Error::Io(err.to_string())

src/tui/ui.rs

@@ -1,3 +1,5 @@
+use std::fmt;
+
 use musichoard::{Album, Artist, Collection, Format, Track};
 use ratatui::{
     backend::Backend,
@@ -9,10 +11,31 @@ use ratatui::{
 
 use super::{lib::IMusicHoard, Error};
 
+#[derive(Debug)]
+pub enum UiError {
+    Lib(String),
+}
+
+impl fmt::Display for UiError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match *self {
+            Self::Lib(ref s) => write!(f, "the musichoard library returned an error: {s}"),
+        }
+    }
+}
+
+impl From<musichoard::Error> for UiError {
+    fn from(err: musichoard::Error) -> UiError {
+        UiError::Lib(err.to_string())
+    }
+}
+
 pub trait IUi {
     fn is_running(&self) -> bool;
     fn quit(&mut self);
 
+    fn save(&mut self) -> Result<(), UiError>;
+
     fn increment_category(&mut self);
     fn decrement_category(&mut self);
 
@@ -440,6 +463,7 @@ impl<'a, 'b> TrackState<'a, 'b> {
 
 impl<MH: IMusicHoard> Ui<MH> {
     pub fn new(mut music_hoard: MH) -> Result<Self, Error> {
+        music_hoard.load_from_database()?;
         music_hoard.rescan_library()?;
         let selection = Selection::new(Some(music_hoard.get_collection()));
         Ok(Ui {
@@ -531,6 +555,11 @@ impl<MH: IMusicHoard> IUi for Ui<MH> {
         self.running = false;
     }
 
+    fn save(&mut self) -> Result<(), UiError> {
+        self.music_hoard.save_to_database()?;
+        Ok(())
+    }
+
     fn increment_category(&mut self) {
         self.selection.increment_category();
     }