opensim-development – Rev 1
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/*
* Copyright (c) Contributors, http://opensimulator.org/
* 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.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of the OpenSimulator Project nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* 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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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
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
{
/// <summary>
/// Cenome memory asset cache.
/// </summary>
/// <remarks>
/// <para>
/// Cache is enabled by setting "AssetCaching" configuration to value "CenomeMemoryAssetCache".
/// When cache is successfully enable log should have message
/// "[ASSET CACHE]: Cenome asset cache enabled (MaxSize = XXX bytes, MaxCount = XXX, ExpirationTime = XXX)".
/// </para>
/// <para>
/// Cache's size is limited by two parameters:
/// maximal allowed size in bytes and maximal allowed asset count. When new asset
/// is added to cache that have achieved either size or count limitation, cache
/// will automatically remove less recently used assets from cache. Additionally
/// asset's lifetime is controlled by expiration time.
/// </para>
/// <para>
/// <list type="table">
/// <listheader>
/// <term>Configuration</term>
/// <description>Description</description>
/// </listheader>
/// <item>
/// <term>MaxSize</term>
/// <description>Maximal size of the cache in bytes. Default value: 128MB (134 217 728 bytes).</description>
/// </item>
/// <item>
/// <term>MaxCount</term>
/// <description>Maximal count of assets stored to cache. Default value: 4096 assets.</description>
/// </item>
/// <item>
/// <term>ExpirationTime</term>
/// <description>Asset's expiration time in minutes. Default value: 30 minutes.</description>
/// </item>
/// </list>
/// </para>
/// </remarks>
/// <example>
/// Enabling Cenome Asset Cache:
/// <code>
/// [Modules]
/// AssetCaching = "CenomeMemoryAssetCache"
/// </code>
/// Setting size and expiration time limitations:
/// <code>
/// [AssetCache]
/// ; 256 MB (default: 134217728)
/// MaxSize = 268435456
/// ; How many assets it is possible to store cache (default: 4096)
/// MaxCount = 16384
/// ; Expiration time - 1 hour (default: 30 minutes)
/// ExpirationTime = 60
/// </code>
/// </example>
[Extension(Path = "/OpenSim/RegionModules", NodeName = "RegionModule", Id = "CenomeMemoryAssetCache")]
public class CenomeMemoryAssetCache : IImprovedAssetCache, ISharedRegionModule
{
private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
/// <summary>
/// Cache's default maximal asset count.
/// </summary>
/// <remarks>
/// <para>
/// Assuming that average asset size is about 32768 bytes.
/// </para>
/// </remarks>
public const int DefaultMaxCount = 4096;
/// <summary>
/// Default maximal size of the cache in bytes
/// </summary>
/// <remarks>
/// <para>
/// 128MB = 128 * 1024^2 = 134 217 728 bytes.
/// </para>
/// </remarks>
public const long DefaultMaxSize = 134217728;
/// <summary>
/// Asset's default expiration time in the cache.
/// </summary>
public static readonly TimeSpan DefaultExpirationTime = TimeSpan.FromMinutes(30.0);
/// <summary>
/// Cache object.
/// </summary>
private ICnmCache<string, AssetBase> m_cache;
/// <summary>
/// Count of cache commands
/// </summary>
private int m_cachedCount;
/// <summary>
/// How many gets before dumping statistics
/// </summary>
/// <remarks>
/// If 0 or less, then disabled.
/// </remarks>
private int m_debugEpoch;
/// <summary>
/// Is Cenome asset cache enabled.
/// </summary>
private bool m_enabled;
/// <summary>
/// Count of get requests
/// </summary>
private int m_getCount;
/// <summary>
/// How many hits
/// </summary>
private int m_hitCount;
/// <summary>
/// Initialize asset cache module, with custom parameters.
/// </summary>
/// <param name="maximalSize">
/// Cache's maximal size in bytes.
/// </param>
/// <param name="maximalCount">
/// Cache's maximal count of assets.
/// </param>
/// <param name="expirationTime">
/// Asset's expiration time.
/// </param>
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);
}
/// <summary>
/// Cache asset.
/// </summary>
/// <param name="asset">
/// The asset that is being cached.
/// </param>
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++;
}
}
/// <summary>
/// Clear asset cache.
/// </summary>
public void Clear()
{
m_cache.Clear();
}
/// <summary>
/// Expire (remove) asset stored to cache.
/// </summary>
/// <param name="id">
/// The expired asset's id.
/// </param>
public void Expire(string id)
{
m_cache.Remove(id);
}
/// <summary>
/// Get asset stored
/// </summary>
/// <param name="id">
/// The asset's id.
/// </param>
/// <returns>
/// Asset if it is found from cache; otherwise <see langword="null"/>.
/// </returns>
/// <remarks>
/// <para>
/// Caller should always check that is return value <see langword="null"/>.
/// Cache doesn't guarantee in any situation that asset is stored to it.
/// </para>
/// </remarks>
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
/// <summary>
/// Gets region module's name.
/// </summary>
public string Name
{
get { return "CenomeMemoryAssetCache"; }
}
public Type ReplaceableInterface
{
get { return null; }
}
/// <summary>
/// New region is being added to server.
/// </summary>
/// <param name="scene">
/// Region's scene.
/// </param>
public void AddRegion(Scene scene)
{
if (m_enabled)
scene.RegisterModuleInterface<IImprovedAssetCache>(this);
}
/// <summary>
/// Close region module.
/// </summary>
public void Close()
{
m_enabled = false;
m_cache.Clear();
m_cache = null;
}
/// <summary>
/// Initialize region module.
/// </summary>
/// <param name="source">
/// Configuration source.
/// </param>
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);
}
/// <summary>
/// Initialization post handling.
/// </summary>
/// <remarks>
/// <para>
/// Modules can use this to initialize connection with other modules.
/// </para>
/// </remarks>
public void PostInitialise()
{
}
/// <summary>
/// Region has been loaded.
/// </summary>
/// <param name="scene">
/// Region's scene.
/// </param>
/// <remarks>
/// <para>
/// This is needed for all module types. Modules will register
/// Interfaces with scene in AddScene, and will also need a means
/// to access interfaces registered by other modules. Without
/// this extra method, a module attempting to use another modules'
/// interface would be successful only depending on load order,
/// which can't be depended upon, or modules would need to resort
/// to ugly kludges to attempt to request interfaces when needed
/// and unnecessary caching logic repeated in all modules.
/// The extra function stub is just that much cleaner.
/// </para>
/// </remarks>
public void RegionLoaded(Scene scene)
{
}
/// <summary>
/// Region is being removed.
/// </summary>
/// <param name="scene">
/// Region scene that is being removed.
/// </param>
public void RemoveRegion(Scene scene)
{
}
#endregion
}
}