fn build()

in core/src/services/persy/backend.rs [79:137]
48 lines of code
6 McCabe index (conditional complexity)

    fn build(&mut self) -> Result<Self::Accessor> {
        let datafile_path = self.datafile.take().ok_or_else(|| {
            Error::new(ErrorKind::ConfigInvalid, "datafile is required but not set")
                .with_context("service", Scheme::Persy)
        })?;

        let segment_name = self.segment.take().ok_or_else(|| {
            Error::new(ErrorKind::ConfigInvalid, "segment is required but not set")
                .with_context("service", Scheme::Persy)
        })?;

        let segment = segment_name.clone();

        let index_name = self.index.take().ok_or_else(|| {
            Error::new(ErrorKind::ConfigInvalid, "index is required but not set")
                .with_context("service", Scheme::Persy)
        })?;

        let index = index_name.clone();

        let persy = persy::OpenOptions::new()
            .create(true)
            .prepare_with(move |p| init(p, &segment_name, &index_name))
            .open(&datafile_path)
            .map_err(|e| {
                Error::new(ErrorKind::ConfigInvalid, "open db")
                    .with_context("service", Scheme::Persy)
                    .with_context("datafile", datafile_path.clone())
                    .set_source(e)
            })?;

        // This function will only be called on database creation
        fn init(
            persy: &persy::Persy,
            segment_name: &str,
            index_name: &str,
        ) -> std::result::Result<(), Box<dyn std::error::Error>> {
            let mut tx = persy.begin()?;

            if !tx.exists_segment(segment_name)? {
                tx.create_segment(segment_name)?;
            }
            if !tx.exists_index(index_name)? {
                tx.create_index::<String, persy::PersyId>(index_name, persy::ValueMode::Replace)?;
            }

            let prepared = tx.prepare()?;
            prepared.commit()?;

            Ok(())
        }

        Ok(PersyBackend::new(Adapter {
            datafile: datafile_path,
            segment,
            index,
            persy,
        }))
    }