Added support for time based eviction policy in structured cache.

2 files changed, 49 insertions, 6 deletions

diff --git a/zenstore/gc.cpp b/zenstore/gc.cpp
index b18a577bf..5aff20e7a 100644
--- a/zenstore/gc.cpp
+++ b/zenstore/gc.cpp
@@ -47,14 +47,17 @@ SaveCompactBinaryObject(const std::filesystem::path& Path, const CbObject& Objec
 
 struct GcContext::GcState
 {
-	CasChunkSet m_CasChunks;
-	CasChunkSet m_CidChunks;
-	bool		m_DeletionMode		 = true;
-	bool		m_ContainerGcEnabled = false;
+	CasChunkSet		   m_CasChunks;
+	CasChunkSet		   m_CidChunks;
+	GcClock::TimePoint m_GcTime;
+	GcClock::Duration  m_MaxCacheDuration	= std::chrono::hours(24);
+	bool			   m_DeletionMode		= true;
+	bool			   m_ContainerGcEnabled = false;
 };
 
-GcContext::GcContext() : m_State(std::make_unique<GcState>())
+GcContext::GcContext(GcClock::TimePoint Time) : m_State(std::make_unique<GcState>())
 {
+	m_State->m_GcTime = Time;
 }
 
 GcContext::~GcContext()
@@ -115,6 +118,24 @@ GcContext::SetContainerGcEnabled(bool NewState)
 	m_State->m_ContainerGcEnabled = NewState;
 }
 
+GcClock::TimePoint
+GcContext::Time() const
+{
+	return m_State->m_GcTime;
+}
+
+GcClock::Duration
+GcContext::MaxCacheDuration() const
+{
+	return m_State->m_MaxCacheDuration;
+}
+
+void
+GcContext::MaxCacheDuration(GcClock::Duration Duration)
+{
+	m_State->m_MaxCacheDuration = Duration;
+}
+
 //////////////////////////////////////////////////////////////////////////
 
 GcContributor::GcContributor(CasGc& Gc) : m_Gc(Gc)
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;