HandleCollector.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / FX-1434 / FX-1434 / 1.0 / untmp / whidbey / REDBITS / ndp / fx / src / Sys / System / Runtime / InteropServices / HandleCollector.cs / 1 / HandleCollector.cs
                        

                        
                            // ==++== 
//
//   Copyright (c) Microsoft Corporation.  All rights reserved.
//
// ==--== 

namespace System.Runtime.InteropServices 
{ 
    using System;
    using System.Threading; 

    public sealed class HandleCollector {
        private const int deltaPercent = 10; // this is used for increasing the threshold.
        private string name; 
        private int initialThreshold;
        private int maximumThreshold; 
        private int threshold; 
        private int handleCount;
 
        private int[] gc_counts = new int [3];
        private int    gc_gen = 0;

        public HandleCollector( string name, int initialThreshold ) : 
            this( name, initialThreshold,  int.MaxValue) {
        } 
 
        public HandleCollector( string name, int initialThreshold, int maximumThreshold ) {
            if( initialThreshold < 0) { 
                throw new ArgumentOutOfRangeException("initialThreshold",
                    SR.GetString(SR.ArgumentOutOfRange_NeedNonNegNumRequired));
            }
 
            if( maximumThreshold < 0) {
                throw new ArgumentOutOfRangeException("maximumThreshold", 
                    SR.GetString(SR.ArgumentOutOfRange_NeedNonNegNumRequired)); 
            }
 
            if( initialThreshold > maximumThreshold) {
                throw new ArgumentException(SR.GetString(SR.Argument_InvalidThreshold));
            }
 
            if ( name != null) {
                this.name = name; 
            } 
            else {
                this.name = String.Empty; 
            }

            this.initialThreshold = initialThreshold;
            this.maximumThreshold = maximumThreshold ; 
            this.threshold = initialThreshold;
            this.handleCount = 0; 
        } 

        public int Count { get {return handleCount;} } 

        public int InitialThreshold { get  { return initialThreshold;} }

        public int MaximumThreshold { get { return  maximumThreshold;} } 

        public string Name { get {return name;} } 
 
        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Reliability", "CA2001:AvoidCallingProblematicMethods")]  // Keep call to GC.Collect()
        public void Add () { 
            int gen_collect = -1;
            Interlocked.Increment( ref handleCount);
            if( handleCount < 0) {
                throw new InvalidOperationException(SR.GetString(SR.InvalidOperation_HCCountOverflow)); 
            }
 
            if (handleCount > threshold) { 
                lock (this) {
                    threshold = handleCount + (handleCount/deltaPercent); 
                    gen_collect = gc_gen;
                    if (gc_gen < 2) {
                        gc_gen++;
                    } 
                }
            } 
 
            if ((gen_collect >= 0) &&
                    ((gen_collect == 0) || 
                    (gc_counts[gen_collect] == GC.CollectionCount (gen_collect)))) {
                    GC.Collect (gen_collect);
                    Thread.Sleep (10*gen_collect);
            } 

            //don't bother with gen0. 
            for (int i = 1; i < 3; i++) { 
                gc_counts [i] = GC.CollectionCount (i);
            } 
        }

        public void Remove () {
            Interlocked.Decrement( ref handleCount); 
            if (handleCount < 0) {
                throw new InvalidOperationException(SR.GetString(SR.InvalidOperation_HCCountOverflow)); 
            } 

            int newThreshold =  handleCount + handleCount/deltaPercent; 
            if (newThreshold < (threshold - threshold/deltaPercent)) {
                lock( this) {
                   if (newThreshold > initialThreshold) {
                        threshold = newThreshold; 
                    }
                    else { 
                        threshold = initialThreshold; 
                    }
                    gc_gen = 0; 
                }
            }

            for (int i = 1; i < 3; i++) { 
                gc_counts [i] = GC.CollectionCount (i);
            } 
        } 
    }
}

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