/// <summary>
/// Returns the WaitEntry of the current thread
/// </summary>
/// <returns></returns>
/// In order to avoid creation and destuction of WaitEntry
/// objects each thread has its own WaitEntry object.
private WaitEntry GetThreadWaitEntry()
{
if (null == _waitEntry)
{
_waitEntry = new WaitEntry();
}
_waitEntry.Reset();
return(_waitEntry);
}
private WaitEntry PopWaiter()
{
WaitEntry waitEntry = this._headWaitEntry._nextWaiterEntry;
WaitEntry entry2 = waitEntry._nextWaiterEntry;
this.RemoveWaiter(waitEntry, true);
this._headWaitEntry._nextWaiterEntry = entry2;
if (null != entry2)
{
entry2._prevWaiterEntry = this._headWaitEntry;
}
return(waitEntry);
}
public WaitEntry CreateWaitHandle(ServerCommand condition)
{
if (!_waitEntryPool.TryPop(out var entry))
{
entry = new WaitEntry(this);
}
entry.Prepare(condition);
lock (_waitHandles)
{
_waitHandles.AddLast(entry);
}
return(entry);
}
public void PushWaitEntry(WaitEntry newWaiterEntry)
{
this.RemoveWaiter(newWaiterEntry, false);
if (null == this._headWaitEntry._nextWaiterEntry)
{
this._headWaitEntry._nextWaiterEntry = newWaiterEntry;
newWaiterEntry._prevWaiterEntry = this._headWaitEntry;
}
else
{
WaitEntry entry = this._headWaitEntry._nextWaiterEntry;
this._headWaitEntry._nextWaiterEntry = newWaiterEntry;
newWaiterEntry._nextWaiterEntry = entry;
newWaiterEntry._prevWaiterEntry = this._headWaitEntry;
entry._prevWaiterEntry = newWaiterEntry;
}
this._waitersCount++;
}
public WorkItem DequeueWorkItem(int millisecondsTimeout, WaitHandle cancelEvent)
{
WaitEntry newWaiterEntry = null;
WorkItem workItem = null;
WorkItemsQueue queue;
lock ((queue = this))
{
this.CheckDisposed();
if (this._workItems.Count > 0)
{
return(this._workItems.Dequeue() as WorkItem);
}
newWaiterEntry = this.GetThreadWaitEntry();
this.PushWaitEntry(newWaiterEntry);
}
WaitHandle[] waitHandles = new WaitHandle[] { newWaiterEntry.WaitHandle, cancelEvent };
int num = WaitHandle.WaitAny(waitHandles, millisecondsTimeout, true);
lock ((queue = this))
{
bool flag = 0 == num;
if (!flag)
{
bool flag2 = newWaiterEntry.Timeout();
if (flag2)
{
this.RemoveWaiter(newWaiterEntry, false);
}
flag = !flag2;
}
if (flag)
{
workItem = newWaiterEntry.WorkItem;
if (workItem == null)
{
workItem = this._workItems.Dequeue() as WorkItem;
}
}
}
return(workItem);
}
/// <summary>
/// Enqueue a work item to the queue.
/// </summary>
public bool EnqueueWorkItem(WorkItem workItem)
{
// A work item cannot be null, since null is used in the WaitForWorkItem() method to indicate timeout or cancel
if (workItem == null)
{
throw new ArgumentNullException("workItem");
}
bool enqueue = true;
// First check if there is a wait entry waiting for work item. During
// the check, timed out waiters are ignored. If there is no waiter then the work item is queued.
lock (this)
{
CheckDisposed();
if (!_isWorkItemsQueueActive)
{
return(false);
}
while (_waitersCount > 0)
{
// Dequeue a waiter.
WaitEntry waitEntry = PopWaiter();
// Signal the waiter. On success break the loop
if (waitEntry.Signal(workItem))
{
enqueue = false;
break;
}
}
if (enqueue)
{
// Enqueue the work item
_workItems.Enqueue(workItem);
}
}
return(true);
}
/// <summary>
/// Pop a waiter from the waiter's stack
/// </summary>
/// <returns>Returns the first waiter in the stack</returns>
private WaitEntry PopWaiter()
{
// Store the current stack head
WaitEntry oldFirstWaiterEntry = _headWaitEntry._nextWaiterEntry;
// Store the new stack head
WaitEntry newHeadWaiterEntry = oldFirstWaiterEntry._nextWaiterEntry;
// Update the old stack head list links and decrement the number waiters.
RemoveWaiter(oldFirstWaiterEntry, true);
// Update the new stack head
_headWaitEntry._nextWaiterEntry = newHeadWaiterEntry;
if (null != newHeadWaiterEntry)
{
newHeadWaiterEntry._prevWaiterEntry = _headWaitEntry;
}
// Return the old stack head
return(oldFirstWaiterEntry);
}
/// <summary>
/// Remove a waiter from the stack
/// </summary>
/// <param name="WaitEntry">A waiter entry to remove</param>
/// <param name="popDecrement">If true the waiter count is always decremented</param>
private void RemoveWaiter(WaitEntry WaitEntry, bool popDecrement)
{
// Store the prev entry in the list
WaitEntry prevWaiterEntry = WaitEntry._prevWaiterEntry;
// Store the next entry in the list
WaitEntry nextWaiterEntry = WaitEntry._nextWaiterEntry;
// A flag to indicate if we need to decrement the waiters count.
// If we got here from PopWaiter then we must decrement.
// If we got here from PushWaitEntry then we decrement only if
// the waiter was already in the stack.
bool decrementCounter = popDecrement;
// Null the waiter's entry links
WaitEntry._prevWaiterEntry = null;
WaitEntry._nextWaiterEntry = null;
// If the waiter entry had a prev link then update it.
// It also means that the waiter is already in the list and we
// need to decrement the waiters count.
if (null != prevWaiterEntry)
{
prevWaiterEntry._nextWaiterEntry = nextWaiterEntry;
decrementCounter = true;
}
// If the waiter entry had a next link then update it.
// It also means that the waiter is already in the list and we
// need to decrement the waiters count.
if (null != nextWaiterEntry)
{
nextWaiterEntry._prevWaiterEntry = prevWaiterEntry;
decrementCounter = true;
}
if (decrementCounter)
{
--_waitersCount;
}
}
private void RemoveWaiter(WaitEntry WaitEntry, bool popDecrement)
{
WorkItemsQueue.WaitEntry entry = WaitEntry._prevWaiterEntry;
WorkItemsQueue.WaitEntry entry2 = WaitEntry._nextWaiterEntry;
bool flag = popDecrement;
WaitEntry._prevWaiterEntry = null;
WaitEntry._nextWaiterEntry = null;
if (null != entry)
{
entry._nextWaiterEntry = entry2;
flag = true;
}
if (null != entry2)
{
entry2._prevWaiterEntry = entry;
flag = true;
}
if (flag)
{
this._waitersCount--;
}
}
/// <summary>
/// Cleanup the work items queue, hence no more work items are allowed to be queued.
/// </summary>
private void Cleanup()
{
lock (this) {
// Deactivate only once
if (!_isWorkItemsQueueActive)
{
return;
}
// Don't queue more work items
_isWorkItemsQueueActive = false;
foreach (WorkItem workItem in _workItems)
{
workItem.DisposeState();
}
// Clear the work items that are already queued
_workItems.Clear();
while (_waitersCount > 0)
{
WaitEntry WaitEntry = PopWaiter();
WaitEntry.Timeout();
}
}
}
/// <summary>
/// Remove a waiter from the stack
/// </summary>
/// <param name="WaitEntry">A waiter entry to remove</param>
/// <param name="popDecrement">If true the waiter count is always decremented</param>
private void RemoveWaiter(WaitEntry WaitEntry, bool popDecrement)
{
// Store the prev entry in the list
WaitEntry prevWaiterEntry = WaitEntry._prevWaiterEntry;
// Store the next entry in the list
WaitEntry nextWaiterEntry = WaitEntry._nextWaiterEntry;
// A flag to indicate if we need to decrement the waiters count.
// If we got here from PopWaiter then we must decrement.
// If we got here from PushWaitEntry then we decrement only if
// the waiter was already in the stack.
bool decrementCounter = popDecrement;
// Null the waiter's entry links
WaitEntry._prevWaiterEntry = null;
WaitEntry._nextWaiterEntry = null;
// If the waiter entry had a prev link then update it.
// It also means that the waiter is already in the list and we
// need to decrement the waiters count.
if (null != prevWaiterEntry)
{
prevWaiterEntry._nextWaiterEntry = nextWaiterEntry;
decrementCounter = true;
}
// If the waiter entry had a next link then update it.
// It also means that the waiter is already in the list and we
// need to decrement the waiters count.
if (null != nextWaiterEntry)
{
nextWaiterEntry._prevWaiterEntry = prevWaiterEntry;
decrementCounter = true;
}
if (decrementCounter)
--_waitersCount;
}
/// <summary>
/// Push a new waiter into the waiter's stack
/// </summary>
/// <param name="newWaiterEntry">A waiter to put in the stack</param>
public void PushWaitEntry(WaitEntry newWaiterEntry)
{
// Remove the waiter if it is already in the stack and
// update waiter's count as needed
RemoveWaiter(newWaiterEntry, false);
// If the stack is empty then newWaiterEntry is the new head of the stack
if (null == _headWaitEntry._nextWaiterEntry)
{
_headWaitEntry._nextWaiterEntry = newWaiterEntry;
newWaiterEntry._prevWaiterEntry = _headWaitEntry;
}
else
{
// If the stack is not empty then put newWaiterEntry as the new head of the stack.
// Save the old first waiter entry
WaitEntry oldFirstWaiterEntry = _headWaitEntry._nextWaiterEntry;
// Update the links
_headWaitEntry._nextWaiterEntry = newWaiterEntry;
newWaiterEntry._nextWaiterEntry = oldFirstWaiterEntry;
newWaiterEntry._prevWaiterEntry = _headWaitEntry;
oldFirstWaiterEntry._prevWaiterEntry = newWaiterEntry;
}
// Increment the number of waiters
++_waitersCount;
}
/// <summary>
/// Returns the WaitEntry of the current thread
/// </summary>
/// <returns></returns>
/// In order to avoid creation and destuction of WaitEntry
/// objects each thread has its own WaitEntry object.
private WaitEntry GetThreadWaitEntry()
{
if (null == _waitEntry)
{
_waitEntry = new WaitEntry();
}
_waitEntry.Reset();
return _waitEntry;
}
private bool WaitCore(int timeoutMs)
{
WaitEntry wait_entry = new WaitEntry();
bool mutexLocked = false;
bool waitEntryLocked = false;
try {
Monitor.try_enter_with_atomic_var(mutex, Timeout.Infinite, false, ref mutexLocked);
if (pending_signals > 0)
{
--pending_signals;
return(true);
}
wait_entry.condition = new object();
wait_entry.previous = null;
wait_entry.next = head;
if (head != null)
{
Unsafe.AsRef <WaitEntry> (head).previous = Unsafe.AsPointer <WaitEntry> (ref wait_entry);
}
head = Unsafe.AsPointer <WaitEntry> (ref wait_entry);
}
finally {
if (mutexLocked)
{
Monitor.Exit(mutex);
}
}
try {
Monitor.try_enter_with_atomic_var(wait_entry.condition, Timeout.Infinite, false, ref waitEntryLocked);
if (!wait_entry.signaled)
{
Monitor.Monitor_wait(wait_entry.condition, timeoutMs, false);
}
}
finally {
if (waitEntryLocked)
{
Monitor.Exit(wait_entry.condition);
}
}
mutexLocked = false;
try {
Monitor.try_enter_with_atomic_var(mutex, Timeout.Infinite, false, ref mutexLocked);
if (!wait_entry.signaled)
{
if (head == Unsafe.AsPointer <WaitEntry> (ref wait_entry))
{
head = wait_entry.next;
}
if (wait_entry.next != null)
{
Unsafe.AsRef <WaitEntry> (wait_entry.next).previous = wait_entry.previous;
}
if (wait_entry.previous != null)
{
Unsafe.AsRef <WaitEntry> (wait_entry.previous).next = wait_entry.next;
}
}
}
finally {
if (mutexLocked)
{
Monitor.Exit(mutex);
}
}
return(wait_entry.signaled);
}
