mirror of
https://github.com/mozilla/gecko-dev.git
synced 2024-12-04 11:26:09 +00:00
147 lines
3.7 KiB
C++
147 lines
3.7 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/. */
|
|
|
|
#include "nsEventQueue.h"
|
|
#include "nsAutoPtr.h"
|
|
#include "mozilla/Logging.h"
|
|
#include "nsThreadUtils.h"
|
|
#include "prthread.h"
|
|
#include "mozilla/ChaosMode.h"
|
|
|
|
using namespace mozilla;
|
|
|
|
static LazyLogModule sEventQueueLog("nsEventQueue");
|
|
#ifdef LOG
|
|
#undef LOG
|
|
#endif
|
|
#define LOG(args) MOZ_LOG(sEventQueueLog, mozilla::LogLevel::Debug, args)
|
|
|
|
nsEventQueue::nsEventQueue(Mutex& aLock)
|
|
: mHead(nullptr)
|
|
, mTail(nullptr)
|
|
, mOffsetHead(0)
|
|
, mOffsetTail(0)
|
|
, mEventsAvailable(aLock, "[nsEventQueue.mEventsAvailable]")
|
|
{
|
|
}
|
|
|
|
nsEventQueue::~nsEventQueue()
|
|
{
|
|
// It'd be nice to be able to assert that no one else is holding the lock,
|
|
// but NSPR doesn't really expose APIs for it.
|
|
NS_ASSERTION(IsEmpty(),
|
|
"Non-empty event queue being destroyed; events being leaked.");
|
|
|
|
if (mHead) {
|
|
FreePage(mHead);
|
|
}
|
|
}
|
|
|
|
bool
|
|
nsEventQueue::GetEvent(bool aMayWait, nsIRunnable** aResult,
|
|
MutexAutoLock& aProofOfLock)
|
|
{
|
|
while (IsEmpty()) {
|
|
if (!aMayWait) {
|
|
if (aResult) {
|
|
*aResult = nullptr;
|
|
}
|
|
return false;
|
|
}
|
|
LOG(("EVENTQ(%p): wait begin\n", this));
|
|
mEventsAvailable.Wait();
|
|
LOG(("EVENTQ(%p): wait end\n", this));
|
|
}
|
|
|
|
if (aResult) {
|
|
MOZ_ASSERT(mOffsetHead < EVENTS_PER_PAGE);
|
|
MOZ_ASSERT_IF(mHead == mTail, mOffsetHead <= mOffsetTail);
|
|
*aResult = mHead->mEvents[mOffsetHead++];
|
|
|
|
MOZ_ASSERT(*aResult);
|
|
MOZ_ASSERT(mOffsetHead <= EVENTS_PER_PAGE);
|
|
|
|
// Check if mHead points to empty Page
|
|
if (mOffsetHead == EVENTS_PER_PAGE) {
|
|
Page* dead = mHead;
|
|
mHead = mHead->mNext;
|
|
FreePage(dead);
|
|
mOffsetHead = 0;
|
|
}
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
void
|
|
nsEventQueue::PutEvent(already_AddRefed<nsIRunnable>&& aRunnable,
|
|
MutexAutoLock& aProofOfLock)
|
|
{
|
|
if (!mHead) {
|
|
mHead = NewPage();
|
|
MOZ_ASSERT(mHead);
|
|
|
|
mTail = mHead;
|
|
mOffsetHead = 0;
|
|
mOffsetTail = 0;
|
|
} else if (mOffsetTail == EVENTS_PER_PAGE) {
|
|
Page* page = NewPage();
|
|
MOZ_ASSERT(page);
|
|
|
|
mTail->mNext = page;
|
|
mTail = page;
|
|
mOffsetTail = 0;
|
|
}
|
|
|
|
nsIRunnable*& queueLocation = mTail->mEvents[mOffsetTail];
|
|
MOZ_ASSERT(!queueLocation);
|
|
queueLocation = aRunnable.take();
|
|
++mOffsetTail;
|
|
LOG(("EVENTQ(%p): notify\n", this));
|
|
mEventsAvailable.Notify();
|
|
}
|
|
|
|
void
|
|
nsEventQueue::PutEvent(nsIRunnable* aRunnable, MutexAutoLock& aProofOfLock)
|
|
{
|
|
nsCOMPtr<nsIRunnable> event(aRunnable);
|
|
PutEvent(event.forget(), aProofOfLock);
|
|
}
|
|
|
|
size_t
|
|
nsEventQueue::Count(MutexAutoLock& aProofOfLock)
|
|
{
|
|
// It is obvious count is 0 when the queue is empty.
|
|
if (!mHead) {
|
|
return 0;
|
|
}
|
|
|
|
/* How we count the number of events in the queue:
|
|
* 1. Let pageCount(x, y) denote the number of pages excluding the tail page
|
|
* where x is the index of head page and y is the index of the tail page.
|
|
* 2. Then we have pageCount(x, y) = y - x.
|
|
*
|
|
* Ex: pageCount(0, 0) = 0 where both head and tail pages point to page 0.
|
|
* pageCount(0, 1) = 1 where head points to page 0 and tail points page 1.
|
|
*
|
|
* 3. number of events = (EVENTS_PER_PAGE * pageCount(x, y))
|
|
* - (empty slots in head page) + (non-empty slots in tail page)
|
|
* = (EVENTS_PER_PAGE * pageCount(x, y)) - mOffsetHead + mOffsetTail
|
|
*/
|
|
|
|
int count = -mOffsetHead;
|
|
|
|
// Compute (EVENTS_PER_PAGE * pageCount(x, y))
|
|
for (Page* page = mHead; page != mTail; page = page->mNext) {
|
|
count += EVENTS_PER_PAGE;
|
|
}
|
|
|
|
count += mOffsetTail;
|
|
MOZ_ASSERT(count >= 0);
|
|
|
|
return count;
|
|
}
|