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// <copyright file="PerfCounters.cs" company="Microsoft">
// Copyright (c) 2009 Microsoft Corporation. All rights reserved.
// </copyright>
using System;
using System.Diagnostics;
using System.Diagnostics.CodeAnalysis;
using System.IO;
using System.Runtime.Caching.Hosting;
using System.Security;
using System.Security.Permissions;
using System.Text;
using System.Threading;
namespace System.Runtime.Caching {
internal sealed class PerfCounters : IDisposable {
private const string PERF_COUNTER_CATEGORY = ".NET Memory Cache 4.0";
private const string CACHE_ENTRIES = "Cache Entries";
private const string CACHE_HITS = "Cache Hits";
private const string CACHE_HIT_RATIO = "Cache Hit Ratio";
private const string CACHE_HIT_RATIO_BASE = "Cache Hit Ratio Base";
private const string CACHE_MISSES = "Cache Misses";
private const string CACHE_TRIMS = "Cache Trims";
private const string CACHE_TURNOVER = "Cache Turnover Rate";
private const int NUM_COUNTERS = 7;
private static string s_appId;
private PerformanceCounter[] _counters;
private long[] _counterValues;
[SecuritySafeCritical]
[PermissionSet(SecurityAction.Assert, Unrestricted = true)]
[SuppressMessage("Microsoft.Security", "CA2106:SecureAsserts", Justification = "Grandfathered suppression from original caching code checkin")]
private static void EnsureAppIdInited() {
if (s_appId == null) {
IApplicationIdentifier ai = null;
IServiceProvider host = ObjectCache.Host;
if (host != null) {
ai = host.GetService(typeof(IApplicationIdentifier)) as IApplicationIdentifier;
}
// if the host has an identifier, use it
string appId = (ai != null) ? ai.GetApplicationId() : null;
// otherwise, use the process name wihtout file extension
if (String.IsNullOrEmpty(appId)) {
StringBuilder sb = new StringBuilder(512);
if (UnsafeNativeMethods.GetModuleFileName(IntPtr.Zero, sb, 512) != 0) {
appId = Path.GetFileNameWithoutExtension(sb.ToString());
}
}
// if all else fails, use AppDomain.FriendlyName
if (String.IsNullOrEmpty(appId)) {
appId = AppDomain.CurrentDomain.FriendlyName;
}
Interlocked.CompareExchange(ref s_appId, appId, null);
}
}
private void InitDisposableMembers(string cacheName) {
bool dispose = true;
try {
StringBuilder sb = (s_appId != null) ? new StringBuilder(s_appId + ":" + cacheName) : new StringBuilder(cacheName);
for (int i = 0; i < sb.Length; i++) {
switch (sb[i]) {
case '(':
sb[i] = '[';
break;
case ')':
sb[i] = ']';
break;
case '/':
case '\\':
case '#':
sb[i] = '_';
break;
}
}
string instanceName = sb.ToString();
_counters = new PerformanceCounter[NUM_COUNTERS];
_counterValues = new long[NUM_COUNTERS];
_counters[(int)PerfCounterName.Entries] = new PerformanceCounter(PERF_COUNTER_CATEGORY, CACHE_ENTRIES, instanceName, false);
_counters[(int)PerfCounterName.Hits] = new PerformanceCounter(PERF_COUNTER_CATEGORY, CACHE_HITS, instanceName, false);
_counters[(int)PerfCounterName.HitRatio] = new PerformanceCounter(PERF_COUNTER_CATEGORY, CACHE_HIT_RATIO, instanceName, false);
_counters[(int)PerfCounterName.HitRatioBase] = new PerformanceCounter(PERF_COUNTER_CATEGORY, CACHE_HIT_RATIO_BASE, instanceName, false);
_counters[(int)PerfCounterName.Misses] = new PerformanceCounter(PERF_COUNTER_CATEGORY, CACHE_MISSES, instanceName, false);
_counters[(int)PerfCounterName.Trims] = new PerformanceCounter(PERF_COUNTER_CATEGORY, CACHE_TRIMS, instanceName, false);
_counters[(int)PerfCounterName.Turnover] = new PerformanceCounter(PERF_COUNTER_CATEGORY, CACHE_TURNOVER, instanceName, false);
dispose = false;
}
finally {
if (dispose) {
Dispose();
}
}
}
private PerfCounters() {
// hide default ctor
}
internal PerfCounters(string cacheName) {
if (cacheName == null) {
throw new ArgumentNullException("cacheName");
}
EnsureAppIdInited();
InitDisposableMembers(cacheName);
}
internal void Decrement(PerfCounterName name) {
int idx = (int) name;
PerformanceCounter counter = _counters[idx];
counter.Decrement();
Interlocked.Decrement(ref _counterValues[idx]);
}
internal void Increment(PerfCounterName name) {
int idx = (int) name;
PerformanceCounter counter = _counters[idx];
counter.Increment();
Interlocked.Increment(ref _counterValues[idx]);
}
internal void IncrementBy(PerfCounterName name, long value) {
int idx = (int) name;
PerformanceCounter counter = _counters[idx];
counter.IncrementBy(value);
Interlocked.Add(ref _counterValues[idx], value);
}
public void Dispose() {
PerformanceCounter[] counters = _counters;
// ensure this only happens once
if (counters != null && Interlocked.CompareExchange(ref _counters, null, counters) == counters) {
for (int i = 0; i < NUM_COUNTERS; i++) {
PerformanceCounter counter = counters[i];
if (counter != null) {
// decrement counter by its current value, to zero it out for this instance of the named cache (see Dev10 Bug 680819)
long value = Interlocked.Exchange(ref _counterValues[i], 0);
if (value != 0) {
counter.IncrementBy(-value);
}
counter.Dispose();
}
}
}
// Don't need to call GC.SuppressFinalize(this) for sealed types without finalizers.
}
}
}
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