Initial QSfera import

Server/vendor/github.com/bluele/gcache/clock.go

@@ -0,0 +1,53 @@
+package gcache
+
+import (
+	"sync"
+	"time"
+)
+
+type Clock interface {
+	Now() time.Time
+}
+
+type RealClock struct{}
+
+func NewRealClock() Clock {
+	return RealClock{}
+}
+
+func (rc RealClock) Now() time.Time {
+	t := time.Now()
+	return t
+}
+
+type FakeClock interface {
+	Clock
+
+	Advance(d time.Duration)
+}
+
+func NewFakeClock() FakeClock {
+	return &fakeclock{
+		// Taken from github.com/jonboulle/clockwork: use a fixture that does not fulfill Time.IsZero()
+		now: time.Date(1984, time.April, 4, 0, 0, 0, 0, time.UTC),
+	}
+}
+
+type fakeclock struct {
+	now time.Time
+
+	mutex sync.RWMutex
+}
+
+func (fc *fakeclock) Now() time.Time {
+	fc.mutex.RLock()
+	defer fc.mutex.RUnlock()
+	t := fc.now
+	return t
+}
+
+func (fc *fakeclock) Advance(d time.Duration) {
+	fc.mutex.Lock()
+	defer fc.mutex.Unlock()
+	fc.now = fc.now.Add(d)
+}