/// <summary>Attempts to obtain an exclusive lock within amount
/// of time given. Currently polls once per second until
/// lockWaitTimeout is passed.
/// </summary>
/// <param name="lockWaitTimeout">length of time to wait in ms
/// </param>
/// <returns> true if lock was obtained
/// </returns>
/// <throws> IOException if lock wait times out or obtain() throws an IOException </throws>
public virtual bool Obtain(long lockWaitTimeout)
{
int sleepCount = 0;
bool locked = Obtain();
int maxSleepCount = (int)(lockWaitTimeout / LOCK_POLL_INTERVAL);
maxSleepCount = System.Math.Min(maxSleepCount, 1);
while (!locked)
{
FSDirectory.Log("Lock.Obtain timeout: sleepcount = {0} (timeout={1},maxsleepcount={2})", sleepCount, lockWaitTimeout, maxSleepCount);
if (sleepCount++ == maxSleepCount)
{
// Try and be a little more verbose on failure
string lockpath = this.ToString();
System.Text.StringBuilder ex = new System.Text.StringBuilder();
ex.Append("Lock obtain timed out: ");
ex.Append(lockpath);
if (System.IO.File.Exists(lockpath))
{
System.IO.FileStream fs = System.IO.File.Open(lockpath, System.IO.FileMode.Open, System.IO.FileAccess.Read, System.IO.FileShare.Read);
System.IO.StreamReader sr = new System.IO.StreamReader(fs);
string pid = sr.ReadToEnd().Trim();
sr.Close();
fs.Close();
ex.Append(" -- pid ").Append(pid);
if (pid == String.Empty)
{
ex.Append("(empty)");
}
else if (System.IO.Directory.Exists("/proc/" + pid))
{
ex.Append(" -- process exists");
}
else
{
ex.Append(" -- process does not exist, stale lockfile?");
}
}
else
{
ex.Append(" -- lock file doesn't exist!?");
}
throw new System.IO.IOException(ex.ToString());
}
System.Threading.Thread.Sleep((int)LOCK_POLL_INTERVAL);
locked = Obtain();
}
return(locked);
}