InternalCache.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / FXUpdate3074 / FXUpdate3074 / 1.1 / untmp / whidbey / QFE / ndp / clr / src / BCL / System / Reflection / Cache / InternalCache.cs / 1 / InternalCache.cs
                        

                        
                            // ==++== 
//
//   Copyright (c) Microsoft Corporation.  All rights reserved.
//
// ==--== 
/*============================================================
** 
** Class: InternalCache 
**
** 
** Purpose: A high-performance internal caching class.  All key
** lookups are done on the basis of the CacheObjType enum.  The
** cache is limited to one object of any particular type per
** instance. 
**
** 
============================================================*/ 
using System;
using System.Threading; 
using System.Diagnostics;
using System.Runtime.CompilerServices;
using System.Runtime.Remoting.Metadata;
 
namespace System.Reflection.Cache {
 
    [Serializable] 
    internal enum CacheAction {
        AllocateCache  = 1, 
            AddItem    = 2,
            ClearCache = 3,
            LookupItemHit  = 4,
            LookupItemMiss = 5, 
            GrowCache  = 6,
            SetItemReplace = 7, 
            ReplaceFailed = 8 
    }
 

    [Serializable] internal class InternalCache {
        private const int MinCacheSize = 2;
 
        //We'll start the cache as null and only grow it as we need it.
        private InternalCacheItem[] m_cache=null; 
        private int m_numItems = 0; 
        //        private bool m_copying = false;
 
        //Knowing the name of the cache is very useful for debugging, but we don't
        //want to take the working-set hit in the debug build.  We'll only include
        //the field in that build.
#if _LOGGING 
        private String m_cacheName;
#endif 
 
        internal InternalCache(String cacheName) {
#if _LOGGING 
            m_cacheName = cacheName;
#endif
            //We won't allocate any items until the first time that they're requested.
        } 

        internal Object this[CacheObjType cacheType] { 
            get { 

                //Let's snapshot a reference to the array up front so that 
                //we don't have to worry about any writers.  It's important
                //to grab the cache first and then numItems.  In the event that
                //the cache gets cleared, m_numItems will be set to 0 before
                //we actually release the cache.  Getting it second will cause 
                //us to walk only 0 elements, but not to fault.
                InternalCacheItem[] cache = m_cache; 
                int numItems = m_numItems; 

                int position = FindObjectPosition(cache, numItems, cacheType, false); 
                if (position>=0) {
                    if (!BCLDebug.m_loggingNotEnabled)
                        LogAction(CacheAction.LookupItemHit, cacheType, cache[position].Value);
                    return cache[position].Value; 
                }
 
                //Couldn't find it -- oh, well. 
                if (!BCLDebug.m_loggingNotEnabled)
                    LogAction(CacheAction.LookupItemMiss, cacheType); 
                return null;
            }

            set { 
                int position;
 
                if (!BCLDebug.m_loggingNotEnabled) 
                    LogAction(CacheAction.AddItem, cacheType, value);
                lock(this) { 
                    position = FindObjectPosition(m_cache, m_numItems, cacheType, true);
                    if (position>0) {
                        m_cache[position].Value = value;
                        m_cache[position].Key = cacheType; 
                        if (position==m_numItems) {
                            m_numItems++; 
                        } 
                        return;
                    } 

                    if (m_cache==null) {
                        if (!BCLDebug.m_loggingNotEnabled)
                            LogAction(CacheAction.AllocateCache, cacheType); 
                        //                        m_copying = true;
                        m_cache = new InternalCacheItem[MinCacheSize]; 
                        m_cache[0].Value = value; 
                        m_cache[0].Key = cacheType;
                        m_numItems = 1; 
                        //                        m_copying = false;
                    } else {
                        if (!BCLDebug.m_loggingNotEnabled)
                            LogAction(CacheAction.GrowCache, cacheType); 

                        //                        m_copying = true; 
                        InternalCacheItem[] tempCache = new InternalCacheItem[m_numItems * 2]; 
                        for (int i=0; i cache.Length) {
                itemCount = cache.Length;
            } 

            for (int i=0; i

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