private bool TryTakeOrPeek(out T result, bool take)
{
ThreadLocalList list = GetThreadList(false);
if (list == null || list.Count == 0)
{
return(Steal(out result, take));
}
bool lockTaken = false;
try {
if (take)
{
Interlocked.Exchange(ref list._currentOp, (int)ListOperation.Take);
if (list.Count <= 2 || _needSync)
{
list._currentOp = (int)ListOperation.None;
Monitor.Enter(list, ref lockTaken);
if (list.Count == 0)
{
if (lockTaken)
{
try { }
finally {
lockTaken = false;
Monitor.Exit(list);
}
}
return(Steal(out result, true));
}
}
list.Remove(out result);
}
else
{
if (!list.Peek(out result))
{
return(Steal(out result, false));
}
}
}
finally {
list._currentOp = (int)ListOperation.None;
if (lockTaken)
{
Monitor.Exit(list);
}
}
return(true);
}
private bool TryTakeOrPeek(out T result, bool take)
{
ThreadLocalList <T> threadList = this.GetThreadList(false);
if ((threadList == null) || (threadList.Count == 0))
{
return(this.Steal(out result, take));
}
bool lockTaken = false;
try
{
if (take)
{
Interlocked.Exchange(ref threadList.m_currentOp, 2);
if ((threadList.Count <= 2) || this.m_needSync)
{
threadList.m_currentOp = 0;
Monitor.Enter(threadList, ref lockTaken);
if (threadList.Count == 0)
{
if (lockTaken)
{
try
{
}
finally
{
lockTaken = false;
Monitor.Exit(threadList);
}
}
return(this.Steal(out result, true));
}
}
threadList.Remove(out result);
}
else if (!threadList.Peek(out result))
{
return(this.Steal(out result, false));
}
}
finally
{
threadList.m_currentOp = 0;
if (lockTaken)
{
Monitor.Exit(threadList);
}
}
return(true);
}
/// <summary>
/// Local helper function to Take or Peek an item from the bag
/// </summary>
/// <param name="result">To receive the item retrieved from the bag</param>
/// <param name="take">True means Take operation, false means Peek operation</param>
/// <returns>True if succeeded, false otherwise</returns>
private bool TryTakeOrPeek(out T result, bool take)
{
// Get the local list for that thread, return null if the thread doesn't exit
//(this thread never add before)
ThreadLocalList list = GetThreadList(false);
if (list == null || list.Count == 0)
{
return(Steal(out result, take));
}
bool lockTaken = false;
try
{
if (take) // Take operation
{
#pragma warning disable 0420
Interlocked.Exchange(ref list._currentOp, (int)ListOperation.Take);
#pragma warning restore 0420
//Synchronization cases:
// if the list count is less than or equal two to avoid conflict with any stealing thread
// if _needSync is set, this means there is a thread that needs to freeze the bag
if (list.Count <= 2 || _needSync)
{
// reset it back to zero to avoid deadlock with stealing thread
list._currentOp = (int)ListOperation.None;
Monitor.Enter(list, ref lockTaken);
// Double check the count and steal if it became empty
if (list.Count == 0)
{
// Release the lock before stealing
if (lockTaken)
{
try { }
finally
{
lockTaken = false; // reset lockTaken to avoid calling Monitor.Exit again in the finally block
Monitor.Exit(list);
}
}
return(Steal(out result, true));
}
}
list.Remove(out result);
}
else
{
if (!list.Peek(out result))
{
return(Steal(out result, false));
}
}
}
finally
{
list._currentOp = (int)ListOperation.None;
if (lockTaken)
{
Monitor.Exit(list);
}
}
return(true);
}