Method import

src/sql.rs:126–175

Imports the database from a separate file with the given passphrase.

(&self, path: &Path, passphrase: String)

    /// Imports the database from a separate file with the given passphrase.
    pub(crate) async fn import(&self, path: &Path, passphrase: String) -> Result<()> {
        let path_str = path
            .to_str()
            .with_context(|| format!("path {path:?} is not valid unicode"))?
            .to_string();

        // Keep `config_cache` locked all the time the db is imported so that nobody can use invalid
        // values from there. And clear it immediately so as not to forget in case of errors.
        let mut config_cache = self.config_cache.write().await;
        config_cache.clear();

        let query_only = false;
        self.call(query_only, move |conn| {
            // Check that backup passphrase is correct before resetting our database.
            conn.execute("ATTACH DATABASE ? AS backup KEY ?", (path_str, passphrase))
                .context("failed to attach backup database")?;
            let res = conn
                .query_row("SELECT count(*) FROM sqlite_master", [], |_row| Ok(()))
                .context("backup passphrase is not correct");

            // Reset the database without reopening it. We don't want to reopen the database because we
            // don't have main database passphrase at this point.
            // See <https://sqlite.org/c3ref/c_dbconfig_enable_fkey.html> for documentation.
            // Without resetting import may fail due to existing tables.
            res.and_then(|_| {
                conn.set_db_config(DbConfig::SQLITE_DBCONFIG_RESET_DATABASE, true)
                    .context("failed to set SQLITE_DBCONFIG_RESET_DATABASE")
            })
            .and_then(|_| {
                conn.execute("VACUUM", [])
                    .context("failed to vacuum the database")
            })
            .and(
                conn.set_db_config(DbConfig::SQLITE_DBCONFIG_RESET_DATABASE, false)
                    .context("failed to unset SQLITE_DBCONFIG_RESET_DATABASE"),
            )
            .and_then(|_| {
                conn.query_row("SELECT sqlcipher_export('main', 'backup')", [], |_row| {
                    Ok(())
                })
                .context("failed to import from attached backup database")
            })
            .and(
                conn.execute("DETACH DATABASE backup", [])
                    .context("failed to detach backup database"),
            )?;
            Ok(())
        })
        .await
    }

    const N_DB_CONNECTIONS: usize = 3;