Cleanup, .clparew can now be ran everyone, modules load appropriate guild configs, IEnumerable<GuildConfig> replaces with NadekoBot.AllGuildConfigs

NadekoBot.Core/Common/Caching/FactoryCache.cs

@@ -0,0 +1,49 @@
+using System;
+
+namespace NadekoBot.Core.Common.Caching
+{
+    /// <summary>
+    /// A caching object which loads its value with a factory method when it expires.
+    /// </summary>
+    /// <typeparam name="T">Type of the value which is cached.</typeparam>
+    public class FactoryCache<T> : IFactoryCache
+    {
+        public DateTime LastUpdate { get; set; } = DateTime.MinValue;
+        private readonly object _locker = new object();
+        private TimeSpan _expireAfter;
+        private readonly Func<T> _factory;
+        private T Value;
+
+        /// <summary>
+        /// Creates a new factory cache object.
+        /// </summary>
+        /// <param name="factory">Method which loads the value when it expires or if it's not loaded the first time.</param>
+        /// <param name="expireAfter">Time after which the value will be reloaded.</param>
+        /// <param name="loadImmediately">Should the value be loaded right away. If set to false, value will load when it's first retrieved.</param>
+        public FactoryCache(Func<T> factory, TimeSpan expireAfter, 
+            bool loadImmediately = false)
+        {
+            _expireAfter = expireAfter;
+            _factory = factory;
+            if (loadImmediately)
+            {
+                Value = _factory();
+                LastUpdate = DateTime.UtcNow;
+            }
+        }
+
+        public T GetValue()
+        {
+            lock (_locker)
+            {
+                if (DateTime.UtcNow - LastUpdate > _expireAfter)
+                {
+                    LastUpdate = DateTime.UtcNow;
+                    return Value = _factory();
+                }
+
+                return Value;
+            }
+        }
+    }
+}