Added support for time based eviction policy in structured cache.

1 files changed, 23 insertions, 1 deletions

diff --git a/zenstore/include/zenstore/gc.h b/zenstore/include/zenstore/gc.h
index 94f3c32ac..b30c70b1f 100644
--- a/zenstore/include/zenstore/gc.h
+++ b/zenstore/include/zenstore/gc.h
@@ -25,13 +25,28 @@ class CasGc;
 class CidStore;
 struct IoHash;
 
+/** GC clock
+ */
+class GcClock
+{
+public:
+	using Clock		= std::chrono::system_clock;
+	using TimePoint = Clock::time_point;
+	using Duration	= Clock::duration;
+	using Tick		= int64_t;
+
+	static Tick		 TickCount() { return Now().time_since_epoch().count(); }
+	static TimePoint Now() { return Clock::now(); }
+	static TimePoint TimePointFromTick(const Tick TickCount) { return TimePoint{Duration{TickCount}}; }
+};
+
 /** Garbage Collection context object
  */
 
 class GcContext
 {
 public:
-	GcContext();
+	GcContext(GcClock::TimePoint Time = GcClock::Now());
 	~GcContext();
 
 	void ContributeCids(std::span<const IoHash> Cid);
@@ -48,6 +63,13 @@ public:
 	bool IsContainerGcEnabled() const;
 	void SetContainerGcEnabled(bool NewState);
 
+	GcClock::TimePoint Time() const;
+
+	GcClock::Duration MaxCacheDuration() const;
+	void			  MaxCacheDuration(GcClock::Duration Duration);
+
+	inline bool Expired(GcClock::Tick TickCount) { return Time() - GcClock::TimePointFromTick(TickCount) > MaxCacheDuration(); }
+
 private:
 	struct GcState;