gcscaching

type StatCache interface {
	// Insert an entry for the given object record.
	//
	// In order to help cope with caching of arbitrarily out of date (i.e.
	// inconsistent) object listings, entry will not replace any positive entry
	// with a newer generation number, or with an equivalent generation number
	// but newer metadata generation number. We have no choice, however, but to
	// replace negative entries.
	//
	// The entry will expire after the supplied time.
	Insert(o *gcs.Object, expiration time.Time)

	// Set up a negative entry for the given name, indicating that the name
	// doesn't exist. Overwrite any existing entry for the name, positive or
	// negative.
	AddNegativeEntry(name string, expiration time.Time)

	// Erase the entry for the given object name, if any.
	Erase(name string)

	// Return the current entry for the given name, or nil if there is a negative
	// entry. Return hit == false when there is neither a positive nor a negative
	// entry, or the entry has expired according to the supplied current time.
	LookUp(name string, now time.Time) (hit bool, o *gcs.Object)

	// Panic if any internal invariants have been violated. The careful user can
	// arrange to call this at crucial moments.
	CheckInvariants()
}