status-go/vendor/github.com/libp2p/go-libp2p-pubsub/timecache/last_seen_cache.go

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package timecache
import (
"context"
"sync"
"time"
)
// LastSeenCache is a time cache that extends the expiry of a seen message when added
// or checked for presence with Has..
type LastSeenCache struct {
lk sync.Mutex
m map[string]time.Time
ttl time.Duration
done func()
}
var _ TimeCache = (*LastSeenCache)(nil)
func newLastSeenCache(ttl time.Duration) *LastSeenCache {
tc := &LastSeenCache{
m: make(map[string]time.Time),
ttl: ttl,
}
ctx, done := context.WithCancel(context.Background())
tc.done = done
go background(ctx, &tc.lk, tc.m)
return tc
}
func (tc *LastSeenCache) Done() {
tc.done()
}
func (tc *LastSeenCache) Add(s string) bool {
tc.lk.Lock()
defer tc.lk.Unlock()
_, ok := tc.m[s]
tc.m[s] = time.Now().Add(tc.ttl)
return !ok
}
func (tc *LastSeenCache) Has(s string) bool {
tc.lk.Lock()
defer tc.lk.Unlock()
_, ok := tc.m[s]
if ok {
tc.m[s] = time.Now().Add(tc.ttl)
}
return ok
}