db

type CompactOptions struct {
	MinReclaimBytes        int64
	MinReclaimPercent      int64
	MinReclaimPercentFloor int64
	// MinInterval also throttles failed attempts.
	MinInterval time.Duration
	// PauseTimeout bounds draining transactions. Zero selects the default.
	PauseTimeout time.Duration
	// CopyTimeout bounds copying independently of the drain. Zero uses the
	// caller's context. Filesystem calls cannot be interrupted.
	CopyTimeout time.Duration
	// Progress receives phase changes without blocking maintenance. A full channel drops updates.
	Progress chan<- string
}

type CompactResult struct {
	// Compacted remains true if a failure occurs after replacement.
	Compacted  bool
	Reason     string
	SizeBefore int64
	SizeAfter  int64
	// Reclaimable includes both free and pending pages.
	Reclaimable int64
	Duration    time.Duration
}

type CompactionStats struct {
	Size int64
	// Reclaimable includes pending pages, which become available after readers drain.
	Reclaimable int64
}

type Compactor interface {
	// CompactionStats returns ErrCompactionBusy rather than waiting for maintenance.
	CompactionStats() (CompactionStats, error)
	Compact(ctx context.Context, opt CompactOptions) (CompactResult, error)
}

type DB interface {
	io.Closer
	Transactor
}

type Transactor interface {
	View(fn func(*bolt.Tx) error) error
	Update(fn func(*bolt.Tx) error) error
}