|
|
@ -0,0 +1,197 @@
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
|
|
|
* Code from: http://www.jackleitch.net/2010/10/better-rate-limiting-with-dot-net/
|
|
|
|
|
|
|
|
*/
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
using System;
|
|
|
|
|
|
|
|
using System.Collections.Concurrent;
|
|
|
|
|
|
|
|
using System.Threading;
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
namespace NzbDrone.Common
|
|
|
|
|
|
|
|
{
|
|
|
|
|
|
|
|
/// <summary>
|
|
|
|
|
|
|
|
/// Used to control the rate of some occurrence per unit of time.
|
|
|
|
|
|
|
|
/// </summary>
|
|
|
|
|
|
|
|
/// <remarks>
|
|
|
|
|
|
|
|
/// <para>
|
|
|
|
|
|
|
|
/// To control the rate of an action using a <see cref="RateGate"/>,
|
|
|
|
|
|
|
|
/// code should simply call <see cref="WaitToProceed()"/> prior to
|
|
|
|
|
|
|
|
/// performing the action. <see cref="WaitToProceed()"/> will block
|
|
|
|
|
|
|
|
/// the current thread until the action is allowed based on the rate
|
|
|
|
|
|
|
|
/// limit.
|
|
|
|
|
|
|
|
/// </para>
|
|
|
|
|
|
|
|
/// <para>
|
|
|
|
|
|
|
|
/// This class is thread safe. A single <see cref="RateGate"/> instance
|
|
|
|
|
|
|
|
/// may be used to control the rate of an occurrence across multiple
|
|
|
|
|
|
|
|
/// threads.
|
|
|
|
|
|
|
|
/// </para>
|
|
|
|
|
|
|
|
/// </remarks>
|
|
|
|
|
|
|
|
public class RateGate : IDisposable
|
|
|
|
|
|
|
|
{
|
|
|
|
|
|
|
|
// Semaphore used to count and limit the number of occurrences per
|
|
|
|
|
|
|
|
// unit time.
|
|
|
|
|
|
|
|
private readonly SemaphoreSlim _semaphore;
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
// Times (in millisecond ticks) at which the semaphore should be exited.
|
|
|
|
|
|
|
|
private readonly ConcurrentQueue<int> _exitTimes;
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
// Timer used to trigger exiting the semaphore.
|
|
|
|
|
|
|
|
private readonly Timer _exitTimer;
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
// Whether this instance is disposed.
|
|
|
|
|
|
|
|
private bool _isDisposed;
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
/// <summary>
|
|
|
|
|
|
|
|
/// Number of occurrences allowed per unit of time.
|
|
|
|
|
|
|
|
/// </summary>
|
|
|
|
|
|
|
|
public int Occurrences { get; private set; }
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
/// <summary>
|
|
|
|
|
|
|
|
/// The length of the time unit, in milliseconds.
|
|
|
|
|
|
|
|
/// </summary>
|
|
|
|
|
|
|
|
public int TimeUnitMilliseconds { get; private set; }
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
/// <summary>
|
|
|
|
|
|
|
|
/// Initializes a <see cref="RateGate"/> with a rate of <paramref name="occurrences"/>
|
|
|
|
|
|
|
|
/// per <paramref name="timeUnit"/>.
|
|
|
|
|
|
|
|
/// </summary>
|
|
|
|
|
|
|
|
/// <param name="occurrences">Number of occurrences allowed per unit of time.</param>
|
|
|
|
|
|
|
|
/// <param name="timeUnit">Length of the time unit.</param>
|
|
|
|
|
|
|
|
/// <exception cref="ArgumentOutOfRangeException">
|
|
|
|
|
|
|
|
/// If <paramref name="occurrences"/> or <paramref name="timeUnit"/> is negative.
|
|
|
|
|
|
|
|
/// </exception>
|
|
|
|
|
|
|
|
public RateGate(int occurrences, TimeSpan timeUnit)
|
|
|
|
|
|
|
|
{
|
|
|
|
|
|
|
|
// Check the arguments.
|
|
|
|
|
|
|
|
if (occurrences <= 0)
|
|
|
|
|
|
|
|
throw new ArgumentOutOfRangeException("occurrences", "Number of occurrences must be a positive integer");
|
|
|
|
|
|
|
|
if (timeUnit != timeUnit.Duration())
|
|
|
|
|
|
|
|
throw new ArgumentOutOfRangeException("timeUnit", "Time unit must be a positive span of time");
|
|
|
|
|
|
|
|
if (timeUnit >= TimeSpan.FromMilliseconds(UInt32.MaxValue))
|
|
|
|
|
|
|
|
throw new ArgumentOutOfRangeException("timeUnit", "Time unit must be less than 2^32 milliseconds");
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Occurrences = occurrences;
|
|
|
|
|
|
|
|
TimeUnitMilliseconds = (int)timeUnit.TotalMilliseconds;
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
// Create the semaphore, with the number of occurrences as the maximum count.
|
|
|
|
|
|
|
|
_semaphore = new SemaphoreSlim(Occurrences, Occurrences);
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
// Create a queue to hold the semaphore exit times.
|
|
|
|
|
|
|
|
_exitTimes = new ConcurrentQueue<int>();
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
// Create a timer to exit the semaphore. Use the time unit as the original
|
|
|
|
|
|
|
|
// interval length because that's the earliest we will need to exit the semaphore.
|
|
|
|
|
|
|
|
_exitTimer = new Timer(ExitTimerCallback, null, TimeUnitMilliseconds, -1);
|
|
|
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
// Callback for the exit timer that exits the semaphore based on exit times
|
|
|
|
|
|
|
|
// in the queue and then sets the timer for the nextexit time.
|
|
|
|
|
|
|
|
private void ExitTimerCallback(object state)
|
|
|
|
|
|
|
|
{
|
|
|
|
|
|
|
|
// While there are exit times that are passed due still in the queue,
|
|
|
|
|
|
|
|
// exit the semaphore and dequeue the exit time.
|
|
|
|
|
|
|
|
int exitTime;
|
|
|
|
|
|
|
|
while (_exitTimes.TryPeek(out exitTime)
|
|
|
|
|
|
|
|
&& unchecked(exitTime - Environment.TickCount) <= 0)
|
|
|
|
|
|
|
|
{
|
|
|
|
|
|
|
|
_semaphore.Release();
|
|
|
|
|
|
|
|
_exitTimes.TryDequeue(out exitTime);
|
|
|
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
// Try to get the next exit time from the queue and compute
|
|
|
|
|
|
|
|
// the time until the next check should take place. If the
|
|
|
|
|
|
|
|
// queue is empty, then no exit times will occur until at least
|
|
|
|
|
|
|
|
// one time unit has passed.
|
|
|
|
|
|
|
|
int timeUntilNextCheck;
|
|
|
|
|
|
|
|
if (_exitTimes.TryPeek(out exitTime))
|
|
|
|
|
|
|
|
timeUntilNextCheck = unchecked(exitTime - Environment.TickCount);
|
|
|
|
|
|
|
|
else
|
|
|
|
|
|
|
|
timeUntilNextCheck = TimeUnitMilliseconds;
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
// Set the timer.
|
|
|
|
|
|
|
|
_exitTimer.Change(timeUntilNextCheck, -1);
|
|
|
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
/// <summary>
|
|
|
|
|
|
|
|
/// Blocks the current thread until allowed to proceed or until the
|
|
|
|
|
|
|
|
/// specified timeout elapses.
|
|
|
|
|
|
|
|
/// </summary>
|
|
|
|
|
|
|
|
/// <param name="millisecondsTimeout">Number of milliseconds to wait, or -1 to wait indefinitely.</param>
|
|
|
|
|
|
|
|
/// <returns>true if the thread is allowed to proceed, or false if timed out</returns>
|
|
|
|
|
|
|
|
public bool WaitToProceed(int millisecondsTimeout)
|
|
|
|
|
|
|
|
{
|
|
|
|
|
|
|
|
// Check the arguments.
|
|
|
|
|
|
|
|
if (millisecondsTimeout < -1)
|
|
|
|
|
|
|
|
throw new ArgumentOutOfRangeException("millisecondsTimeout");
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
CheckDisposed();
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
// Block until we can enter the semaphore or until the timeout expires.
|
|
|
|
|
|
|
|
var entered = _semaphore.Wait(millisecondsTimeout);
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
// If we entered the semaphore, compute the corresponding exit time
|
|
|
|
|
|
|
|
// and add it to the queue.
|
|
|
|
|
|
|
|
if (entered)
|
|
|
|
|
|
|
|
{
|
|
|
|
|
|
|
|
var timeToExit = unchecked(Environment.TickCount + TimeUnitMilliseconds);
|
|
|
|
|
|
|
|
_exitTimes.Enqueue(timeToExit);
|
|
|
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
return entered;
|
|
|
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
/// <summary>
|
|
|
|
|
|
|
|
/// Blocks the current thread until allowed to proceed or until the
|
|
|
|
|
|
|
|
/// specified timeout elapses.
|
|
|
|
|
|
|
|
/// </summary>
|
|
|
|
|
|
|
|
/// <param name="timeout"></param>
|
|
|
|
|
|
|
|
/// <returns>true if the thread is allowed to proceed, or false if timed out</returns>
|
|
|
|
|
|
|
|
public bool WaitToProceed(TimeSpan timeout)
|
|
|
|
|
|
|
|
{
|
|
|
|
|
|
|
|
return WaitToProceed((int)timeout.TotalMilliseconds);
|
|
|
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
/// <summary>
|
|
|
|
|
|
|
|
/// Blocks the current thread indefinitely until allowed to proceed.
|
|
|
|
|
|
|
|
/// </summary>
|
|
|
|
|
|
|
|
public void WaitToProceed()
|
|
|
|
|
|
|
|
{
|
|
|
|
|
|
|
|
WaitToProceed(Timeout.Infinite);
|
|
|
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
// Throws an ObjectDisposedException if this object is disposed.
|
|
|
|
|
|
|
|
private void CheckDisposed()
|
|
|
|
|
|
|
|
{
|
|
|
|
|
|
|
|
if (_isDisposed)
|
|
|
|
|
|
|
|
throw new ObjectDisposedException("RateGate is already disposed");
|
|
|
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
/// <summary>
|
|
|
|
|
|
|
|
/// Releases unmanaged resources held by an instance of this class.
|
|
|
|
|
|
|
|
/// </summary>
|
|
|
|
|
|
|
|
public void Dispose()
|
|
|
|
|
|
|
|
{
|
|
|
|
|
|
|
|
Dispose(true);
|
|
|
|
|
|
|
|
GC.SuppressFinalize(this);
|
|
|
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
/// <summary>
|
|
|
|
|
|
|
|
/// Releases unmanaged resources held by an instance of this class.
|
|
|
|
|
|
|
|
/// </summary>
|
|
|
|
|
|
|
|
/// <param name="isDisposing">Whether this object is being disposed.</param>
|
|
|
|
|
|
|
|
protected virtual void Dispose(bool isDisposing)
|
|
|
|
|
|
|
|
{
|
|
|
|
|
|
|
|
if (!_isDisposed)
|
|
|
|
|
|
|
|
{
|
|
|
|
|
|
|
|
if (isDisposing)
|
|
|
|
|
|
|
|
{
|
|
|
|
|
|
|
|
// The semaphore and timer both implement IDisposable and
|
|
|
|
|
|
|
|
// therefore must be disposed.
|
|
|
|
|
|
|
|
_semaphore.Dispose();
|
|
|
|
|
|
|
|
_exitTimer.Dispose();
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
_isDisposed = true;
|
|
|
|
|
|
|
|
}
|
|
|
|
|
|
|
|
}
|
|
|
|
|
|
|
|
}
|
|
|
|
|
|
|
|
}
|
|
|
|
|
|
|
|
}
|