Imported Upstream version 4.0.0~alpha1

Former-commit-id: 806294f5ded97629b74c85c09952f2a74fe182d9

mcs/class/System.Runtime.Caching/ReferenceSources/CacheExpires.cs

@@ -0,0 +1,81 @@
+// This file implements the classes ExpiresEntryRef and CacheExpires missing from .NET reference source
+
+using System.Threading;
+
+namespace System.Runtime.Caching
+{
+	class ExpiresEntryRef
+	{
+		public static ExpiresEntryRef INVALID = new ExpiresEntryRef ();
+
+		public bool IsInvalid {
+			get { return this == INVALID; }
+		}
+	}
+
+	class CacheExpiresHelper : ICacheEntryHelper
+	{
+		public int Compare(MemoryCacheEntry entry1, MemoryCacheEntry entry2)
+		{
+			return DateTime.Compare (entry1.UtcAbsExp , entry2.UtcAbsExp);
+		}
+
+		public DateTime GetDateTime (MemoryCacheEntry entry)
+		{
+			return entry.UtcAbsExp;
+		}
+	}
+
+	class CacheExpires : CacheEntryCollection
+	{
+
+		public static TimeSpan MIN_UPDATE_DELTA = new TimeSpan (0, 0, 1);
+		public static TimeSpan EXPIRATIONS_INTERVAL = new TimeSpan (0, 0, 20);
+		public static CacheExpiresHelper helper = new CacheExpiresHelper ();
+
+		Timer timer;
+
+		public CacheExpires (MemoryCacheStore store)
+			: base (store, helper)
+		{
+		}
+
+		public void Add (MemoryCacheEntry entry)
+		{
+			entry.ExpiresEntryRef = new ExpiresEntryRef ();
+			base.Add (entry);
+		}
+
+		public void Remove (MemoryCacheEntry entry)
+		{
+			base.Remove (entry);
+			entry.ExpiresEntryRef = ExpiresEntryRef.INVALID;
+		}
+
+		public void UtcUpdate (MemoryCacheEntry entry, DateTime utcAbsExp)
+		{
+			base.Remove (entry);
+			entry.UtcAbsExp = utcAbsExp;
+			base.Add (entry);
+		}
+
+		public void EnableExpirationTimer (bool enable)
+		{
+			if (enable) {
+				if (timer != null)
+					return;
+
+				var period = (int) EXPIRATIONS_INTERVAL.TotalMilliseconds;
+				timer = new Timer ((o) => FlushExpiredItems (true), null, period, period);
+			} else {
+				timer.Dispose ();
+				timer = null;
+			}
+		}
+
+		public int FlushExpiredItems (bool blockInsert)
+		{
+			return base.FlushItems (DateTime.UtcNow, CacheEntryRemovedReason.Expired, blockInsert);
+		}
+	}
+}