fn start_compaction()

in common/rusty_leveldb_sgx/src/db_impl.rs [668:719]

• 49 lines of code
• 5 McCabe index (conditional complexity)

    fn start_compaction(&mut self, mut compaction: Compaction) -> Result<()> {
        if compaction.is_trivial_move() {
            assert_eq!(1, compaction.num_inputs(0));
            let f = compaction.input(0, 0);
            let num = f.num;
            let size = f.size;
            let level = compaction.level();

            compaction.edit().delete_file(level, num);
            compaction.edit().add_file(level + 1, f);

            let r = self.vset.borrow_mut().log_and_apply(compaction.into_edit());
            if let Err(e) = r {
                log!(self.opt.log, "trivial move failed: {}", e);
                Err(e)
            } else {
                log!(
                    self.opt.log,
                    "Moved num={} bytes={} from L{} to L{}",
                    num,
                    size,
                    level,
                    level + 1
                );
                log!(
                    self.opt.log,
                    "Summary: {}",
                    self.vset.borrow().current_summary()
                );
                Ok(())
            }
        } else {
            let smallest = if self.snaps.empty() {
                self.vset.borrow().last_seq
            } else {
                self.snaps.oldest()
            };
            let mut state = CompactionState::new(compaction, smallest);
            if let Err(e) = self.do_compaction_work(&mut state) {
                state.cleanup(&self.opt.env, &self.path);
                log!(self.opt.log, "Compaction work failed: {}", e);
            }
            self.install_compaction_results(state)?;
            log!(
                self.opt.log,
                "Compaction finished: {}",
                self.vset.borrow().current_summary()
            );

            self.delete_obsolete_files()
        }
    }