TimeoutTimer.cs source code in C# .NET

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                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / Data / System / Data / ProviderBase / TimeoutTimer.cs / 1305376 / TimeoutTimer.cs
                        
                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// 
//  Class used to manage timeouts in complex system operations.
// 
// [....] 
// [....]
//----------------------------------------------------------------------------- 

namespace System.Data.ProviderBase
{
    using System; 
    using System.Data.Common;
    using System.Diagnostics; 
 
// Purpose:
//   Manages determining and tracking timeouts 
//
// Intended use:
//   Call StartXXXXTimeout() to get a timer with the given expiration point
//   Get remaining time in appropriate format to pass to subsystem timeouts 
//   Check for timeout via IsExpired for checks in managed code.
//   Simply abandon to GC when done. 
internal class TimeoutTimer 
{
    //------------------- 
    // Fields
    //-------------------
    private long _timerExpire;
    private bool _isInfiniteTimeout; 

    //------------------- 
    // Timeout-setting methods 
    //-------------------
 
    // Get a new timer that will expire in the given number of seconds
    //  For input, a value of zero seconds indicates infinite timeout
    internal static TimeoutTimer StartSecondsTimeout(int seconds)
    { 
        //--------------------
        // Preconditions: None (seconds must conform to SetTimeoutSeconds requirements) 
 
        //--------------------
        // Method body 
        var timeout = new TimeoutTimer();
        timeout.SetTimeoutSeconds(seconds);

        //--------------------- 
        // Postconditions
        Debug.Assert(timeout != null); // Need a valid timeouttimer if no error 
 
        return timeout;
    } 

#if !ORACLE
    // Get a new timer that will expire in the given number of milliseconds
    //  No current need to support infinite milliseconds timeout 
    internal static TimeoutTimer StartMillisecondsTimeout(long milliseconds)
    { 
        //-------------------- 
        // Preconditions
        Debug.Assert(0 <= milliseconds); 

        //--------------------
        // Method body
        var timeout = new TimeoutTimer(); 
        timeout._timerExpire = checked(ADP.TimerCurrent() + (milliseconds * TimeSpan.TicksPerMillisecond));
        timeout._isInfiniteTimeout = false; 
 
        //---------------------
        // Postconditions 
        Debug.Assert(timeout != null); // Need a valid timeouttimer if no error

        return timeout;
    } 
#endif
 
    //------------------- 
    // Methods for changing timeout
    //------------------- 

    internal void SetTimeoutSeconds(int seconds)
    {
        //-------------------- 
        // Preconditions
        Debug.Assert(0 <= seconds || InfiniteTimeout == seconds);  // no need to support negative seconds at present 
 
        //--------------------
        // Method body 
        if (InfiniteTimeout == seconds)
        {
            _isInfiniteTimeout = true;
        } 
        else
        { 
            // Stash current time + timeout 
            _timerExpire = checked(ADP.TimerCurrent() + ADP.TimerFromSeconds(seconds));
            _isInfiniteTimeout = false; 
        }

        //---------------------
        // Postconditions:None 
    }
 
    //------------------- 
    // Timeout info properties
    //------------------- 

    // Indicator for infinite timeout when starting a timer
    internal static readonly long InfiniteTimeout = 0;
 
    // Is this timer in an expired state?
    internal bool IsExpired 
    { 
        get
        { 
            return !IsInfinite && ADP.TimerHasExpired(_timerExpire);
        }
    }
 
    // is this an infinite-timeout timer?
    internal bool IsInfinite 
    { 
        get
        { 
            return _isInfiniteTimeout;
        }
    }
 
    // Special accessor for TimerExpire for use when thunking to legacy timeout methods.
    internal long LegacyTimerExpire 
    { 
        get
        { 
            return (_isInfiniteTimeout) ? Int64.MaxValue : _timerExpire;
        }
    }
 
    // Returns milliseconds remaining trimmed to zero for none remaining
    //  and long.MaxValue for infinite 
    // This method should be prefered for internal calculations that are not 
    //  yet common enough to code into the TimeoutTimer class itself.
    internal long MillisecondsRemaining 
    {
        get
        {
            //------------------- 
            // Preconditions: None
 
            //------------------- 
            // Method Body
            long milliseconds; 
            if (_isInfiniteTimeout)
            {
                milliseconds = long.MaxValue;
            } 
            else
            { 
                milliseconds = ADP.TimerRemainingMilliseconds(_timerExpire); 
                if (0 > milliseconds)
                { 
                    milliseconds = 0;
                }
            }
 
            //--------------------
            // Postconditions 
            Debug.Assert(0<=milliseconds); // This property guarantees no negative return values 

            return milliseconds; 
        }
    }

} 

} 
 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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TimeoutTimer.cs source code in C# .NET

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