/// <summary>
/// Try to get the actual file lock on behalf of the current request.
/// </summary>
/// <param name="currentRequest"></param>
/// <returns></returns>
private bool TryGetLock(DistributedLock currentRequest)
{
var waitForLock = currentRequest.WaitForLock;
var lockTimeout = currentRequest.WaitTimeout;
var validLock = false;
while (waitForLock == false || DateTimeOffset.Now < lockTimeout)
{
if (DateTimeOffset.Now >= _minTimeNextTurn) // Make sure we aren't in a back-off delay.
{
var newLock = _provider.GetLock(_name);
if (newLock != null)
{
lock (_currentLockLock)
{
_lock = newLock;
// We have the lock! Close our lock request if we have one so later we can detect if anyone else does.
if (_lockRequest != null)
{
_lockRequest.Dispose();
_lockRequest = null;
}
}
validLock = true; // Report that we have the lock now.
}
}
// Otherwise, just pretend we couldn't get the lock in this attempt.
if (validLock == false && waitForLock)
{
// We didn't get the lock and we want to wait for it, so try to open a lock request.
lock (_currentLockLock)
{
if (_lockRequest == null)
{
_lockRequest = _provider.GetLockRequest(_name); // Tell the other process we'd like a turn.
}
}
// Then we should allow some real time to pass before trying again because external locks aren't very fast.
Thread.Sleep(LockPollingDelay);
}
else
{
// We either got the lock or the user doesn't want to keep retrying, so exit the loop.
break;
}
}
return(validLock);
}