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// Copyright (c) 2011 Oracle Inc.
//
// 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;
using System.Data;
using System.Collections.Generic;
using MySql.Data.MySqlClient.Properties;
using System.Diagnostics;
using System.Text;
using System.Globalization;
namespace MySql.Data.MySqlClient
{
internal class TableCache
{
private static 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();
}
}
public class BaseTableCache
{
protected int MaxCacheAge;
private Dictionary<string, CacheEntry> cache = new Dictionary<string, CacheEntry>();
public BaseTableCache(int maxCacheAge)
{
MaxCacheAge = maxCacheAge;
}
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);
}
}
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;
}
}
public void RemoveFromCache(string commandText)
{
lock (cache)
{
if (!cache.ContainsKey(commandText)) return;
cache.Remove(commandText);
}
}
public virtual void Dump()
{
lock (cache)
cache.Clear();
}
protected virtual void CleanCache()
{
DateTime now = DateTime.Now;
List<string> keysToRemove =new List<string>();
lock (cache)
{
foreach (string key in cache.Keys)
{
TimeSpan diff = now.Subtract(cache[key].CacheTime);
if (diff.TotalSeconds > MaxCacheAge)
keysToRemove.Add(key);
}
foreach (string key in keysToRemove)
cache.Remove(key);
}
}
private struct CacheEntry
{
public DateTime CacheTime;
public object CacheElement;
}
}
}
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