diff --git a/memo/memo.go b/memo/memo.go index 893bc79..8a88ccd 100644 --- a/memo/memo.go +++ b/memo/memo.go @@ -1,78 +1,79 @@ package memo import ( "sync" "time" ) type ( Memo struct { f Func mu sync.Mutex //guards cache cache *entry cacheDur time.Duration lastCache time.Time } Func func() (interface{}, error) ) type ( entry struct { res result ready chan struct{} // close when res is read } result struct { value interface{} err error } ) func New(f Func, cd time.Duration) *Memo { return &Memo{ f: f, cacheDur: cd, } } // Invalidate resets the cache to nil if the memo's given cache duration has // elapsed, and returns true if the cache was actually invalidated. func (memo *Memo) Invalidate() bool { defer memo.mu.Unlock() memo.mu.Lock() if memo.cache != nil && time.Now().Sub(memo.lastCache) > memo.cacheDur { memo.cache = nil memo.lastCache = time.Now() return true } return false } func (memo *Memo) Get() (value interface{}, err error) { memo.mu.Lock() if memo.cache == nil { memo.cache = &entry{ready: make(chan struct{})} memo.mu.Unlock() memo.cache.res.value, memo.cache.res.err = memo.f() close(memo.cache.ready) } else { memo.mu.Unlock() <-memo.cache.ready } return memo.cache.res.value, memo.cache.res.err } -// Reset forcibly resets the cache to nil. +// Reset forcibly resets the cache to nil without checking if the cache +// duration has elapsed. func (memo *Memo) Reset() { defer memo.mu.Unlock() memo.mu.Lock() memo.cache = nil memo.lastCache = time.Now() }