Default Database

The default crate provides default components for managing source files and a database in the db module:

• BaseDb: A basic database implementation using Salsa.
• File: A struct representing a source file.
• BaseDatabase: A trait for file retrieval.
• FileManager: A trait for file updates.

These components are designed to cover common use cases but can be extended or replaced to suit your project’s specific needs.

File struct

The File struct is a salsa::input representing a source file, its Url, and a reference to its parser configuration.

#[salsa::input]
pub struct File {
    #[id]
    pub url: Url,
    pub parsers: &'static Parsers,
    #[return_ref]
    pub document: Arc<Document>,
}

BaseDb struct

BaseDb is the default implementation of a database. It stores File inputs.

#![allow(unused)]
fn main() {
#[salsa::db]
#[derive(Default, Clone)]
pub struct BaseDb {
    storage: Storage<Self>,
    pub(crate) files: DashMap<Url, File>,
}
}

To enable logging, use the with_logger method to initialize the database with a logger closure.

BaseDatabase trait

The BaseDatabase trait defines how to access stored files. It's meant to be implemented by any Salsa-compatible database. It is used to retrieve files from the database.

#[salsa::db]
pub trait BaseDatabase: Database {
    fn get_files(&self) -> &DashMap<Url, File>;

    fn get_file(&self, url: &Url) -> Option<File> {
        self.get_files().get(url).map(|file| *file)
    }
}

FileManager trait

The FileManager trait provides high-level methods to manage files (add, update, remove). It is implemented for any type that also implements BaseDatabase.

pub trait FileManager: BaseDatabase + salsa::Database {
    fn add_file_from_texter(
        &mut self,
        parsers: &'static Parsers,
        url: &Url,
        texter: Text,
    ) -> Result<(), DataBaseError>;

    fn update(
        &mut self,
        url: &Url,
        changes: &[lsp_types::TextDocumentContentChangeEvent],
    ) -> Result<(), DataBaseError>;

    fn remove_file(&mut self, url: &Url) -> Result<(), DataBaseError>;
}