TrackingMemoryStream.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / wpf / src / Base / MS / Internal / IO / Packaging / TrackingMemoryStream.cs / 1305600 / TrackingMemoryStream.cs
                        

                        
                            //------------------------------------------------------------------------------ 
//
// 
//    Copyright (C) Microsoft Corporation.  All rights reserved.
//  
//
// Description: 
//  This is a stream that is capable of reporting data usage up to the registered 
//  owner
// 
// History:
//  05/24/2005: IgorBel: Initial creation.
//  11/08/2005: BruceMac: Change namespace
// 
//-----------------------------------------------------------------------------
 
using System; 
using System.Diagnostics;
using System.IO; 

namespace MS.Internal.IO.Packaging
{
    // making this class sealed as it is taking advantage of some Virtual methods 
    // in MemoryStream(Capacity); therefore, there is a danger of subclass overriding those and unexpected
    // behavior changes. Consider calls from Constructor->ReportIfNecessary->Capacity 
    // prior to unsealing this class (they would be marked as FxCop violations) 
    internal sealed class TrackingMemoryStream : MemoryStream
    { 
        // other constructors can be added later, as we need them, for now we only use the following 2
        internal TrackingMemoryStream(ITrackingMemoryStreamFactory memoryStreamFactory): base()
        {
            // although we could have implemented this constructor in terms of the other constructor; we shouldn't. 
            // It seems safer to always call the equivalent base class constructor, as we might be ignorant about
            // some minor differences between various MemoryStream constructors 
            Debug.Assert(memoryStreamFactory != null); 
            _memoryStreamFactory = memoryStreamFactory;
            ReportIfNeccessary(); 
        }

        internal TrackingMemoryStream (ITrackingMemoryStreamFactory memoryStreamFactory, Int32 capacity) : base(capacity)
        { 
            Debug.Assert(memoryStreamFactory != null);
            _memoryStreamFactory = memoryStreamFactory; 
            ReportIfNeccessary(); 
        }
 

        // Here are the overrides for members that could possible result in changes in the allocated memory
        public override int Read(byte[] buffer, int offset, int count)
        { 
            int result = base.Read(buffer, offset, count);
 
            ReportIfNeccessary(); 
            return result;
        } 

        public override void Write(byte[] buffer, int offset, int count)
        {
            base.Write(buffer, offset, count); 

            ReportIfNeccessary(); 
        } 

        public override void SetLength(long value) 
        {
            base.SetLength(value);

            ReportIfNeccessary(); 
        }
 
        protected override void Dispose(bool disposing) 
        {
            try 
            {
                if (disposing)
                {
                    if (_memoryStreamFactory != null) 
                    {
                        // release all the memory, and report it to the TrackingMemoryStreamFactory 
                        SetLength(0); 
                        Capacity = 0;
                        ReportIfNeccessary(); 
                        _memoryStreamFactory = null;
                    }
                }
            } 
            finally
            { 
                base.Dispose(disposing); 
            }
        } 

        private void ReportIfNeccessary ()
        {
            if (this.Capacity !=_lastReportedHighWaterMark) 
            {
                // we need to report the new memory being allocated as a part of the constructor 
                _memoryStreamFactory.ReportMemoryUsageDelta(checked(this.Capacity - _lastReportedHighWaterMark)); 
                _lastReportedHighWaterMark = this.Capacity;
            } 
        }

        private ITrackingMemoryStreamFactory _memoryStreamFactory;
        private int _lastReportedHighWaterMark; 
    }
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.

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