// Add adds the response of a request to the cache if its revision is larger than the compacted revision of the cache.
func (c *cache) Add(req *pb.RangeRequest, resp *pb.RangeResponse) {
key := keyFunc(req)
c.mu.Lock()
defer c.mu.Unlock()
if req.Revision > c.compactedRev {
c.lru.Add(key, resp)
}
// we do not need to invalidate a request with a revision specified.
// so we do not need to add it into the reverse index.
if req.Revision != 0 {
return
}
var (
iv *adt.IntervalValue
ivl adt.Interval
)
if len(req.RangeEnd) != 0 {
ivl = adt.NewStringAffineInterval(string(req.Key), string(req.RangeEnd))
} else {
ivl = adt.NewStringAffinePoint(string(req.Key))
}
iv = c.cachedRanges.Find(ivl)
if iv == nil {
c.cachedRanges.Insert(ivl, []string{key})
} else {
iv.Val = append(iv.Val.([]string), key)
}
}
// watcherSetByKey gets the set of watchers that recieve events on the given key.
func (wg *watcherGroup) watcherSetByKey(key string) watcherSet {
wkeys := wg.keyWatchers[key]
wranges := wg.ranges.Stab(adt.NewStringAffinePoint(key))
// zero-copy cases
switch {
case len(wranges) == 0:
// no need to merge ranges or copy; reuse single-key set
return wkeys
case len(wranges) == 0 && len(wkeys) == 0:
return nil
case len(wranges) == 1 && len(wkeys) == 0:
return wranges[0].Val.(watcherSet)
}
// copy case
ret := make(watcherSet)
ret.union(wg.keyWatchers[key])
for _, item := range wranges {
ret.union(item.Val.(watcherSet))
}
return ret
}
// Invalidate invalidates the cache entries that intersecting with the given range from key to endkey.
func (c *cache) Invalidate(key, endkey []byte) {
c.mu.Lock()
defer c.mu.Unlock()
var (
ivs []*adt.IntervalValue
ivl adt.Interval
)
if len(endkey) == 0 {
ivl = adt.NewStringAffinePoint(string(key))
} else {
ivl = adt.NewStringAffineInterval(string(key), string(endkey))
}
ivs = c.cachedRanges.Stab(ivl)
for _, iv := range ivs {
keys := iv.Val.([]string)
for _, key := range keys {
c.lru.Remove(key)
}
}
// delete after removing all keys since it is destructive to 'ivs'
c.cachedRanges.Delete(ivl)
}
// contains is whether the given key has a watcher in the group.
func (wg *watcherGroup) contains(key string) bool {
_, ok := wg.keyWatchers[key]
return ok || wg.ranges.Contains(adt.NewStringAffinePoint(key))
}