#if MYSQL_6_10 // Copyright ?2016, 2018, Oracle and/or its affiliates. All rights reserved. // // MySQL Connector/NET is licensed under the terms of the GPLv2 // <http://www.gnu.org/licenses/old-licenses/gpl-2.0.html>, like most // MySQL Connectors. There are special exceptions to the terms and // conditions of the GPLv2 as it is applied to this software, see the // FLOSS License Exception // <http://www.mysql.com/about/legal/licensing/foss-exception.html>. // // This program is free software; you can redistribute it and/or modify // it under the terms of the GNU General Public License as published // by the Free Software Foundation; version 2 of the License. // // This program is distributed in the hope that it will be useful, but // WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY // or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License // for more details. // // You should have received a copy of the GNU General Public License along // with this program; if not, write to the Free Software Foundation, Inc., // 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA using System; using System.Collections.Generic; using System.Linq; namespace Externals.MySql.Data.MySqlClient { internal class TableCache { private static readonly BaseTableCache cache; static TableCache() { cache = new BaseTableCache(480 /* 8 hour max by default */); } public static void AddToCache(string commandText, ResultSet resultSet) { cache.AddToCache(commandText, resultSet); } public static ResultSet RetrieveFromCache(string commandText, int cacheAge) { return (ResultSet)cache.RetrieveFromCache(commandText, cacheAge); } public static void RemoveFromCache(string commandText) { cache.RemoveFromCache(commandText); } public static void DumpCache() { cache.Dump(); } } /// <summary> /// Defines the basic operations to be performed on the table cache. /// </summary> internal class BaseTableCache { /// <summary> /// The maximum age allowed for cache entries. /// </summary> protected int MaxCacheAge; private Dictionary<string, CacheEntry> cache = new Dictionary<string, CacheEntry>(); public BaseTableCache(int maxCacheAge) { MaxCacheAge = maxCacheAge; } /// <summary> /// Adds the given command and result set to the cache. /// </summary> /// <param name="commandText">The command to store in the cache.</param> /// <param name="resultSet">The resultset associated to the stored command.</param> public virtual void AddToCache(string commandText, object resultSet) { CleanCache(); CacheEntry entry = new CacheEntry(); entry.CacheTime = DateTime.Now; entry.CacheElement = resultSet; lock (cache) { if (cache.ContainsKey(commandText)) return; cache.Add(commandText, entry); } } /// <summary> /// Retrieves the specified command from the cache. /// </summary> /// <param name="commandText">The command to retrieve.</param> /// <param name="cacheAge">The allowed age for the cache entry.</param> /// <returns></returns> public virtual object RetrieveFromCache(string commandText, int cacheAge) { CleanCache(); lock (cache) { if (!cache.ContainsKey(commandText)) return null; CacheEntry entry = cache[commandText]; if (DateTime.Now.Subtract(entry.CacheTime).TotalSeconds > cacheAge) return null; return entry.CacheElement; } } /// <summary> /// Removes the specified command from the cache. /// </summary> /// <param name="commandText">The command to remove from the cache.</param> public void RemoveFromCache(string commandText) { lock (cache) { if (!cache.ContainsKey(commandText)) return; cache.Remove(commandText); } } /// <summary> /// Clears the cache. /// </summary> public virtual void Dump() { lock (cache) cache.Clear(); } /// <summary> /// Removes cache entries older than the value defined by <see cref="MaxCacheAge"/>. /// </summary> protected virtual void CleanCache() { DateTime now = DateTime.Now; List<string> keysToRemove = new List<string>(); lock (cache) { keysToRemove.AddRange(from key in cache.Keys let diff = now.Subtract(cache[key].CacheTime) where diff.TotalSeconds > MaxCacheAge select key); foreach (string key in keysToRemove) cache.Remove(key); } } private struct CacheEntry { public DateTime CacheTime; public object CacheElement; } } } #endif