mirror of
https://github.com/classilla/tenfourfox.git
synced 2024-09-11 02:56:06 +00:00
113 lines
3.2 KiB
C++
113 lines
3.2 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
|
|
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
|
|
/* This Source Code Form is subject to the terms of the Mozilla Public
|
|
* License, v. 2.0. If a copy of the MPL was not distributed with this
|
|
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
|
|
|
|
#ifndef nsEventQueue_h__
|
|
#define nsEventQueue_h__
|
|
|
|
#include <stdlib.h>
|
|
#include "mozilla/CondVar.h"
|
|
#include "mozilla/Mutex.h"
|
|
#include "nsIRunnable.h"
|
|
#include "nsCOMPtr.h"
|
|
#include "mozilla/AlreadyAddRefed.h"
|
|
|
|
class nsThreadPool;
|
|
|
|
// A threadsafe FIFO event queue...
|
|
class nsEventQueue
|
|
{
|
|
public:
|
|
typedef mozilla::MutexAutoLock MutexAutoLock;
|
|
|
|
explicit nsEventQueue(mozilla::Mutex& aLock);
|
|
~nsEventQueue();
|
|
|
|
// This method adds a new event to the pending event queue. The queue holds
|
|
// a strong reference to the event after this method returns. This method
|
|
// cannot fail.
|
|
void PutEvent(nsIRunnable* aEvent, MutexAutoLock& aProofOfLock);
|
|
void PutEvent(already_AddRefed<nsIRunnable>&& aEvent,
|
|
MutexAutoLock& aProofOfLock);
|
|
|
|
// This method gets an event from the event queue. If mayWait is true, then
|
|
// the method will block the calling thread until an event is available. If
|
|
// the event is null, then the method returns immediately indicating whether
|
|
// or not an event is pending. When the resulting event is non-null, the
|
|
// caller is responsible for releasing the event object. This method does
|
|
// not alter the reference count of the resulting event.
|
|
bool GetEvent(bool aMayWait, nsIRunnable** aEvent,
|
|
MutexAutoLock& aProofOfLock);
|
|
|
|
// This method returns true if there is a pending event.
|
|
bool HasPendingEvent(MutexAutoLock& aProofOfLock)
|
|
{
|
|
return GetEvent(false, nullptr, aProofOfLock);
|
|
}
|
|
|
|
// This method returns the next pending event or null.
|
|
bool GetPendingEvent(nsIRunnable** aRunnable, MutexAutoLock& aProofOfLock)
|
|
{
|
|
return GetEvent(false, aRunnable, aProofOfLock);
|
|
}
|
|
|
|
size_t Count(MutexAutoLock&);
|
|
|
|
private:
|
|
bool IsEmpty()
|
|
{
|
|
return !mHead || (mHead == mTail && mOffsetHead == mOffsetTail);
|
|
}
|
|
|
|
enum
|
|
{
|
|
EVENTS_PER_PAGE = 255
|
|
};
|
|
|
|
// Page objects are linked together to form a simple deque.
|
|
|
|
struct Page
|
|
{
|
|
struct Page* mNext;
|
|
nsIRunnable* mEvents[EVENTS_PER_PAGE];
|
|
};
|
|
|
|
static_assert((sizeof(Page) & (sizeof(Page) - 1)) == 0,
|
|
"sizeof(Page) should be a power of two to avoid heap slop.");
|
|
|
|
static Page* NewPage()
|
|
{
|
|
return static_cast<Page*>(moz_xcalloc(1, sizeof(Page)));
|
|
}
|
|
|
|
static void FreePage(Page* aPage)
|
|
{
|
|
free(aPage);
|
|
}
|
|
|
|
Page* mHead;
|
|
Page* mTail;
|
|
|
|
uint16_t mOffsetHead; // offset into mHead where next item is removed
|
|
uint16_t mOffsetTail; // offset into mTail where next item is added
|
|
mozilla::CondVar mEventsAvailable;
|
|
|
|
// These methods are made available to nsThreadPool as a hack, since
|
|
// nsThreadPool needs to have its threads sleep for fixed amounts of
|
|
// time as well as being able to wake up all threads when thread
|
|
// limits change.
|
|
friend class nsThreadPool;
|
|
void Wait(PRIntervalTime aInterval)
|
|
{
|
|
mEventsAvailable.Wait(aInterval);
|
|
}
|
|
void NotifyAll()
|
|
{
|
|
mEventsAvailable.NotifyAll();
|
|
}
|
|
};
|
|
|
|
#endif // nsEventQueue_h__
|