CenomeAssetCache.cs

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/*
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 * See CONTRIBUTORS.TXT for a full list of copyright holders.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
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 *       notice, this list of conditions and the following disclaimer.
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 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
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 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
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 * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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using System;
using System.Reflection;
using log4net;
using Mono.Addins;
using Nini.Config;
using OpenSim.Framework;
using OpenSim.Region.Framework.Interfaces;
using OpenSim.Region.Framework.Scenes;

namespace OpenSim.Region.CoreModules.Asset
{
    [Extension(Path = "/OpenSim/RegionModules", NodeName = "RegionModule", Id = "CenomeMemoryAssetCache")]
    public class CenomeMemoryAssetCache : IImprovedAssetCache, ISharedRegionModule
    {
        private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
        
        public const int DefaultMaxCount = 4096;

        public const long DefaultMaxSize = 134217728;

        public static readonly TimeSpan DefaultExpirationTime = TimeSpan.FromMinutes(30.0);
        
        private ICnmCache<string, AssetBase> m_cache;

        private int m_cachedCount;

        private int m_debugEpoch;

        private bool m_enabled;

        private int m_getCount;

        private int m_hitCount;

        protected void Initialize(long maximalSize, int maximalCount, TimeSpan expirationTime)
        {
            if (maximalSize <= 0 || maximalCount <= 0)
            {
                //m_log.Debug("[ASSET CACHE]: Cenome asset cache is not enabled.");
                m_enabled = false;
                return;
            }

            if (expirationTime <= TimeSpan.Zero)
            {
                // Disable expiration time
                expirationTime = TimeSpan.MaxValue;
            }

            // Create cache and add synchronization wrapper over it
            m_cache =
                CnmSynchronizedCache<string, AssetBase>.Synchronized(new CnmMemoryCache<string, AssetBase>(
                    maximalSize, maximalCount, expirationTime));
            m_enabled = true;
            m_log.DebugFormat(
                "[ASSET CACHE]: Cenome asset cache enabled (MaxSize = {0} bytes, MaxCount = {1}, ExpirationTime = {2})",
                maximalSize,
                maximalCount,
                expirationTime);
        }

        #region IImprovedAssetCache Members

        public bool Check(string id)
        {
            AssetBase asset;

            // XXX:This is probably not an efficient implementation.
            return m_cache.TryGetValue(id, out asset);
        }

        public void Cache(AssetBase asset)
        {
            if (asset != null)
            {
//                m_log.DebugFormat("[CENOME ASSET CACHE]: Caching asset {0}", asset.ID);
                
                long size = asset.Data != null ? asset.Data.Length : 1;
                m_cache.Set(asset.ID, asset, size);
                m_cachedCount++;
            }

        }

        public void Clear()
        {
            m_cache.Clear();
        }

        public void Expire(string id)
        {
            m_cache.Remove(id);
        }

        public AssetBase Get(string id)
        {
            m_getCount++;
            AssetBase assetBase;
            if (m_cache.TryGetValue(id, out assetBase))
                m_hitCount++;

            if (m_getCount == m_debugEpoch)
            {
                m_log.DebugFormat(
                    "[ASSET CACHE]: Cached = {0}, Get = {1}, Hits = {2}%, Size = {3} bytes, Avg. A. Size = {4} bytes",
                    m_cachedCount,
                    m_getCount,
                    ((double) m_hitCount / m_getCount) * 100.0,
                    m_cache.Size,
                    m_cache.Size / m_cache.Count);
                m_getCount = 0;
                m_hitCount = 0;
                m_cachedCount = 0;
            }

//            if (null == assetBase)
//                m_log.DebugFormat("[CENOME ASSET CACHE]: Asset {0} not in cache", id);
            
            return assetBase;
        }

        #endregion

        #region ISharedRegionModule Members

        public string Name
        {
            get { return "CenomeMemoryAssetCache"; }
        }

        public Type ReplaceableInterface 
        {
            get { return null; }
        }

        public void AddRegion(Scene scene)
        {
            if (m_enabled)
                scene.RegisterModuleInterface<IImprovedAssetCache>(this);
        }

        public void Close()
        {
            if (m_enabled)
            {
                m_enabled = false;
                m_cache.Clear();
                m_cache = null;
            }
        }

        public void Initialise(IConfigSource source)
        {
            m_cache = null;
            m_enabled = false;

            IConfig moduleConfig = source.Configs[ "Modules" ];
            if (moduleConfig == null)
                return;

            string name = moduleConfig.GetString("AssetCaching");
            //m_log.DebugFormat("[XXX] name = {0} (this module's name: {1}", name, Name);

            if (name != Name)
                return;
            
            long maxSize = DefaultMaxSize;
            int maxCount = DefaultMaxCount;
            TimeSpan expirationTime = DefaultExpirationTime;

            IConfig assetConfig = source.Configs["AssetCache"];
            if (assetConfig != null)
            {
                // Get optional configurations
                maxSize = assetConfig.GetLong("MaxSize", DefaultMaxSize);
                maxCount = assetConfig.GetInt("MaxCount", DefaultMaxCount);
                expirationTime =
                    TimeSpan.FromMinutes(assetConfig.GetInt("ExpirationTime", (int)DefaultExpirationTime.TotalMinutes));

                // Debugging purposes only
                m_debugEpoch = assetConfig.GetInt("DebugEpoch", 0);
            }

            Initialize(maxSize, maxCount, expirationTime);
        }

        public void PostInitialise()
        {
        }

        public void RegionLoaded(Scene scene)
        {
        }

        public void RemoveRegion(Scene scene)
        {
        }

        #endregion
    }
}