pjs/layout/base/nsRefreshDriver.cpp

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Исходник Обычный вид История

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set shiftwidth=2 tabstop=8 autoindent cindent expandtab: */
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is nsRefreshDriver.
*
* The Initial Developer of the Original Code is the Mozilla Foundation.
* Portions created by the Initial Developer are Copyright (C) 2009
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* L. David Baron <dbaron@dbaron.org>, Mozilla Corporation (original author)
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
/*
* Code to notify things that animate before a refresh, at an appropriate
* refresh rate. (Perhaps temporary, until replaced by compositor.)
*/
#include "mozilla/Util.h"
#include "nsRefreshDriver.h"
#include "nsPresContext.h"
#include "nsComponentManagerUtils.h"
#include "prlog.h"
#include "nsAutoPtr.h"
#include "nsCSSFrameConstructor.h"
#include "nsIDocument.h"
#include "nsGUIEvent.h"
#include "nsEventDispatcher.h"
#include "jsapi.h"
#include "nsContentUtils.h"
#include "mozilla/Preferences.h"
#include "nsIViewManager.h"
using mozilla::TimeStamp;
using mozilla::TimeDuration;
using namespace mozilla;
#define DEFAULT_FRAME_RATE 60
#define DEFAULT_THROTTLED_FRAME_RATE 1
static bool sPrecisePref;
/* static */ void
nsRefreshDriver::InitializeStatics()
{
Preferences::AddBoolVarCache(&sPrecisePref,
"layout.frame_rate.precise",
false);
}
/* static */ PRInt32
nsRefreshDriver::DefaultInterval()
{
return NSToIntRound(1000.0 / DEFAULT_FRAME_RATE);
}
// Compute the interval to use for the refresh driver timer, in
// milliseconds
PRInt32
nsRefreshDriver::GetRefreshTimerInterval() const
{
const char* prefName =
mThrottled ? "layout.throttled_frame_rate" : "layout.frame_rate";
PRInt32 rate = Preferences::GetInt(prefName, -1);
if (rate <= 0) {
// TODO: get the rate from the platform
rate = mThrottled ? DEFAULT_THROTTLED_FRAME_RATE : DEFAULT_FRAME_RATE;
}
NS_ASSERTION(rate > 0, "Must have positive rate here");
PRInt32 interval = NSToIntRound(1000.0/rate);
if (mThrottled) {
interval = NS_MAX(interval, mLastTimerInterval * 2);
}
mLastTimerInterval = interval;
return interval;
}
PRInt32
nsRefreshDriver::GetRefreshTimerType() const
{
if (mThrottled) {
return nsITimer::TYPE_ONE_SHOT;
}
if (HaveFrameRequestCallbacks() || sPrecisePref) {
Bug 650379. Add a new XPCOM timer type that is like TYPE_REPEATING_PRECISE but does not swamp the event queue if the callback takes longer than the timer interval to run. r=cjones, sr=brendan This implements proposal 3 from bug 650379 comment 13. The main difference between TYPE_REPEATING_PRECISE and TYPE_REPEATING_PRECISE_CAN_SKIP is to not AddTimer the REPEATING_PRECISE_CAN_SKIP timer until after the callback has run; this guarantees that no more timer events will be posted until after the callback finishes executing. A secondary change is to make REPEATING_PRECISE_CAN_SKIP timers advance their firing time to mDelay from when PostTimerEvent is called, not mDelay from the old mTimeout. While this arguably makes them less precise, the alternative is that if a timer is significantly delayed for some reason (e.g. because the user puts the computer to sleep for a while) it will then fire a whole bunch of times to "catch up" to where it's supposed to be, advancing its firing time by mDelay at a time. That seems undesirable. An alternate approach would have been to readd the timer from inside PostTimerEvent, but only if we're not in the middle of firing the timer. That would allow more precise timers in the case when the callback is not taking too long, but still handle gracefully the case when the callback is slow. Unfortunately this falls down if something _else_ is hogging the main thread event loop (e.g. some other timer has a slow callback, or whatever); in that case we would post multiple events for the one precise timer while the event-loop-hogging operation is running. So I don't think we should do that.
2011-04-29 03:33:52 +04:00
return nsITimer::TYPE_REPEATING_PRECISE_CAN_SKIP;
}
return nsITimer::TYPE_REPEATING_SLACK;
}
nsRefreshDriver::nsRefreshDriver(nsPresContext *aPresContext)
: mPresContext(aPresContext),
mFrozen(false),
mThrottled(false),
mTestControllingRefreshes(false),
mTimerIsPrecise(false),
mViewManagerFlushIsPending(false),
mLastTimerInterval(0)
{
mRequests.Init();
}
nsRefreshDriver::~nsRefreshDriver()
{
NS_ABORT_IF_FALSE(ObserverCount() == 0,
"observers should have unregistered");
NS_ABORT_IF_FALSE(!mTimer, "timer should be gone");
}
// Method for testing. See nsIDOMWindowUtils.advanceTimeAndRefresh
// for description.
void
nsRefreshDriver::AdvanceTimeAndRefresh(PRInt64 aMilliseconds)
{
mTestControllingRefreshes = true;
mMostRecentRefreshEpochTime += aMilliseconds * 1000;
mMostRecentRefresh += TimeDuration::FromMilliseconds(aMilliseconds);
nsCxPusher pusher;
if (pusher.PushNull()) {
Notify(nsnull);
pusher.Pop();
}
}
void
nsRefreshDriver::RestoreNormalRefresh()
{
mTestControllingRefreshes = false;
nsCxPusher pusher;
if (pusher.PushNull()) {
Notify(nsnull); // will call UpdateMostRecentRefresh()
pusher.Pop();
}
}
TimeStamp
nsRefreshDriver::MostRecentRefresh() const
{
const_cast<nsRefreshDriver*>(this)->EnsureTimerStarted(false);
return mMostRecentRefresh;
}
PRInt64
nsRefreshDriver::MostRecentRefreshEpochTime() const
{
const_cast<nsRefreshDriver*>(this)->EnsureTimerStarted(false);
return mMostRecentRefreshEpochTime;
}
bool
nsRefreshDriver::AddRefreshObserver(nsARefreshObserver *aObserver,
mozFlushType aFlushType)
{
ObserverArray& array = ArrayFor(aFlushType);
bool success = array.AppendElement(aObserver) != nsnull;
EnsureTimerStarted(false);
return success;
}
bool
nsRefreshDriver::RemoveRefreshObserver(nsARefreshObserver *aObserver,
mozFlushType aFlushType)
{
ObserverArray& array = ArrayFor(aFlushType);
return array.RemoveElement(aObserver);
}
bool
nsRefreshDriver::AddImageRequest(imgIRequest* aRequest)
{
if (!mRequests.PutEntry(aRequest)) {
return false;
}
EnsureTimerStarted(false);
return true;
}
void
nsRefreshDriver::RemoveImageRequest(imgIRequest* aRequest)
{
mRequests.RemoveEntry(aRequest);
}
void nsRefreshDriver::ClearAllImageRequests()
{
mRequests.Clear();
}
void
nsRefreshDriver::EnsureTimerStarted(bool aAdjustingTimer)
{
if (mTimer || mFrozen || !mPresContext) {
// It's already been started, or we don't want to start it now or
// we've been disconnected.
return;
}
if (!aAdjustingTimer) {
// If we didn't already have a timer and aAdjustingTimer is false,
// then we just got our first observer (or an explicit call to
// MostRecentRefresh by a caller who's likely to add an observer
// shortly). This means we should fake a most-recent-refresh time
// of now so that said observer gets a reasonable refresh time, so
// things behave as though the timer had always been running.
UpdateMostRecentRefresh();
}
mTimer = do_CreateInstance(NS_TIMER_CONTRACTID);
if (!mTimer) {
return;
}
PRInt32 timerType = GetRefreshTimerType();
Bug 650379. Add a new XPCOM timer type that is like TYPE_REPEATING_PRECISE but does not swamp the event queue if the callback takes longer than the timer interval to run. r=cjones, sr=brendan This implements proposal 3 from bug 650379 comment 13. The main difference between TYPE_REPEATING_PRECISE and TYPE_REPEATING_PRECISE_CAN_SKIP is to not AddTimer the REPEATING_PRECISE_CAN_SKIP timer until after the callback has run; this guarantees that no more timer events will be posted until after the callback finishes executing. A secondary change is to make REPEATING_PRECISE_CAN_SKIP timers advance their firing time to mDelay from when PostTimerEvent is called, not mDelay from the old mTimeout. While this arguably makes them less precise, the alternative is that if a timer is significantly delayed for some reason (e.g. because the user puts the computer to sleep for a while) it will then fire a whole bunch of times to "catch up" to where it's supposed to be, advancing its firing time by mDelay at a time. That seems undesirable. An alternate approach would have been to readd the timer from inside PostTimerEvent, but only if we're not in the middle of firing the timer. That would allow more precise timers in the case when the callback is not taking too long, but still handle gracefully the case when the callback is slow. Unfortunately this falls down if something _else_ is hogging the main thread event loop (e.g. some other timer has a slow callback, or whatever); in that case we would post multiple events for the one precise timer while the event-loop-hogging operation is running. So I don't think we should do that.
2011-04-29 03:33:52 +04:00
mTimerIsPrecise = (timerType == nsITimer::TYPE_REPEATING_PRECISE_CAN_SKIP);
nsresult rv = mTimer->InitWithCallback(this,
GetRefreshTimerInterval(),
timerType);
if (NS_FAILED(rv)) {
mTimer = nsnull;
}
}
void
nsRefreshDriver::StopTimer()
{
if (!mTimer) {
return;
}
mTimer->Cancel();
mTimer = nsnull;
}
PRUint32
nsRefreshDriver::ObserverCount() const
{
PRUint32 sum = 0;
for (PRUint32 i = 0; i < ArrayLength(mObservers); ++i) {
sum += mObservers[i].Length();
}
// Even while throttled, we need to process layout and style changes. Style
// changes can trigger transitions which fire events when they complete, and
// layout changes can affect media queries on child documents, triggering
// style changes, etc.
sum += mStyleFlushObservers.Length();
sum += mLayoutFlushObservers.Length();
sum += mFrameRequestCallbackDocs.Length();
sum += mViewManagerFlushIsPending;
return sum;
}
PRUint32
nsRefreshDriver::ImageRequestCount() const
{
return mRequests.Count();
}
void
nsRefreshDriver::UpdateMostRecentRefresh()
{
if (mTestControllingRefreshes) {
return;
}
// Call JS_Now first, since that can have nonzero latency in some rare cases.
mMostRecentRefreshEpochTime = JS_Now();
mMostRecentRefresh = TimeStamp::Now();
}
nsRefreshDriver::ObserverArray&
nsRefreshDriver::ArrayFor(mozFlushType aFlushType)
{
switch (aFlushType) {
case Flush_Style:
return mObservers[0];
case Flush_Layout:
return mObservers[1];
case Flush_Display:
return mObservers[2];
default:
NS_ABORT_IF_FALSE(false, "bad flush type");
return *static_cast<ObserverArray*>(nsnull);
}
}
/*
* nsISupports implementation
*/
NS_IMPL_ISUPPORTS1(nsRefreshDriver, nsITimerCallback)
/*
* nsITimerCallback implementation
*/
NS_IMETHODIMP
nsRefreshDriver::Notify(nsITimer *aTimer)
{
NS_PRECONDITION(!mFrozen, "Why are we notified while frozen?");
NS_PRECONDITION(mPresContext, "Why are we notified after disconnection?");
NS_PRECONDITION(!nsContentUtils::GetCurrentJSContext(),
"Shouldn't have a JSContext on the stack");
if (mTestControllingRefreshes && aTimer) {
// Ignore real refreshes from our timer (but honor the others).
return NS_OK;
}
UpdateMostRecentRefresh();
nsCOMPtr<nsIPresShell> presShell = mPresContext->GetPresShell();
if (!presShell || (ObserverCount() == 0 && ImageRequestCount() == 0)) {
// Things are being destroyed, or we no longer have any observers.
// We don't want to stop the timer when observers are initially
// removed, because sometimes observers can be added and removed
// often depending on what other things are going on and in that
// situation we don't want to thrash our timer. So instead we
// wait until we get a Notify() call when we have no observers
// before stopping the timer.
StopTimer();
return NS_OK;
}
/*
* The timer holds a reference to |this| while calling |Notify|.
* However, implementations of |WillRefresh| are permitted to destroy
* the pres context, which will cause our |mPresContext| to become
* null. If this happens, we must stop notifying observers.
*/
for (PRUint32 i = 0; i < ArrayLength(mObservers); ++i) {
ObserverArray::EndLimitedIterator etor(mObservers[i]);
while (etor.HasMore()) {
nsRefPtr<nsARefreshObserver> obs = etor.GetNext();
obs->WillRefresh(mMostRecentRefresh);
if (!mPresContext || !mPresContext->GetPresShell()) {
StopTimer();
return NS_OK;
}
}
if (i == 0) {
// Grab all of our frame request callbacks up front.
nsIDocument::FrameRequestCallbackList frameRequestCallbacks;
for (PRUint32 i = 0; i < mFrameRequestCallbackDocs.Length(); ++i) {
mFrameRequestCallbackDocs[i]->
TakeFrameRequestCallbacks(frameRequestCallbacks);
}
// OK, now reset mFrameRequestCallbackDocs so they can be
// readded as needed.
mFrameRequestCallbackDocs.Clear();
PRInt64 eventTime = mMostRecentRefreshEpochTime / PR_USEC_PER_MSEC;
for (PRUint32 i = 0; i < frameRequestCallbacks.Length(); ++i) {
nsAutoMicroTask mt;
frameRequestCallbacks[i]->Sample(eventTime);
}
// This is the Flush_Style case.
if (mPresContext && mPresContext->GetPresShell()) {
nsAutoTArray<nsIPresShell*, 16> observers;
observers.AppendElements(mStyleFlushObservers);
for (PRUint32 j = observers.Length();
j && mPresContext && mPresContext->GetPresShell(); --j) {
// Make sure to not process observers which might have been removed
// during previous iterations.
nsIPresShell* shell = observers[j - 1];
if (!mStyleFlushObservers.Contains(shell))
continue;
NS_ADDREF(shell);
mStyleFlushObservers.RemoveElement(shell);
shell->FrameConstructor()->mObservingRefreshDriver = false;
shell->FlushPendingNotifications(Flush_Style);
NS_RELEASE(shell);
}
}
} else if (i == 1) {
// This is the Flush_Layout case.
if (mPresContext && mPresContext->GetPresShell()) {
nsAutoTArray<nsIPresShell*, 16> observers;
observers.AppendElements(mLayoutFlushObservers);
for (PRUint32 j = observers.Length();
j && mPresContext && mPresContext->GetPresShell(); --j) {
// Make sure to not process observers which might have been removed
// during previous iterations.
nsIPresShell* shell = observers[j - 1];
if (!mLayoutFlushObservers.Contains(shell))
continue;
NS_ADDREF(shell);
mLayoutFlushObservers.RemoveElement(shell);
shell->mReflowScheduled = false;
shell->mSuppressInterruptibleReflows = false;
shell->FlushPendingNotifications(Flush_InterruptibleLayout);
NS_RELEASE(shell);
}
}
}
}
/*
* Perform notification to imgIRequests subscribed to listen
* for refresh events.
*/
ImageRequestParameters parms = {mMostRecentRefresh};
if (mRequests.Count()) {
mRequests.EnumerateEntries(nsRefreshDriver::ImageRequestEnumerator, &parms);
EnsureTimerStarted(false);
}
if (mViewManagerFlushIsPending) {
mViewManagerFlushIsPending = false;
mPresContext->GetPresShell()->GetViewManager()->ProcessPendingUpdates();
}
if (mThrottled ||
(mTimerIsPrecise !=
Bug 650379. Add a new XPCOM timer type that is like TYPE_REPEATING_PRECISE but does not swamp the event queue if the callback takes longer than the timer interval to run. r=cjones, sr=brendan This implements proposal 3 from bug 650379 comment 13. The main difference between TYPE_REPEATING_PRECISE and TYPE_REPEATING_PRECISE_CAN_SKIP is to not AddTimer the REPEATING_PRECISE_CAN_SKIP timer until after the callback has run; this guarantees that no more timer events will be posted until after the callback finishes executing. A secondary change is to make REPEATING_PRECISE_CAN_SKIP timers advance their firing time to mDelay from when PostTimerEvent is called, not mDelay from the old mTimeout. While this arguably makes them less precise, the alternative is that if a timer is significantly delayed for some reason (e.g. because the user puts the computer to sleep for a while) it will then fire a whole bunch of times to "catch up" to where it's supposed to be, advancing its firing time by mDelay at a time. That seems undesirable. An alternate approach would have been to readd the timer from inside PostTimerEvent, but only if we're not in the middle of firing the timer. That would allow more precise timers in the case when the callback is not taking too long, but still handle gracefully the case when the callback is slow. Unfortunately this falls down if something _else_ is hogging the main thread event loop (e.g. some other timer has a slow callback, or whatever); in that case we would post multiple events for the one precise timer while the event-loop-hogging operation is running. So I don't think we should do that.
2011-04-29 03:33:52 +04:00
(GetRefreshTimerType() == nsITimer::TYPE_REPEATING_PRECISE_CAN_SKIP))) {
// Stop the timer now and restart it here. Stopping is in the mThrottled
// case ok because either it's already one-shot, and it just fired, and all
// we need to do is null it out, or it's repeating and we need to reset it
// to be one-shot. Stopping and restarting in the case when we need to
// switch from precise to slack timers or vice versa is unfortunately
// required.
// Note that the EnsureTimerStarted() call here is ok because
// EnsureTimerStarted makes sure to not start the timer if it shouldn't be
// started.
StopTimer();
EnsureTimerStarted(true);
}
return NS_OK;
}
PLDHashOperator
nsRefreshDriver::ImageRequestEnumerator(nsISupportsHashKey* aEntry,
void* aUserArg)
{
ImageRequestParameters* parms =
static_cast<ImageRequestParameters*> (aUserArg);
mozilla::TimeStamp mostRecentRefresh = parms->ts;
imgIRequest* req = static_cast<imgIRequest*>(aEntry->GetKey());
NS_ABORT_IF_FALSE(req, "Unable to retrieve the image request");
nsCOMPtr<imgIContainer> image;
req->GetImage(getter_AddRefs(image));
if (image) {
image->RequestRefresh(mostRecentRefresh);
}
return PL_DHASH_NEXT;
}
void
nsRefreshDriver::Freeze()
{
NS_ASSERTION(!mFrozen, "Freeze called on already-frozen refresh driver");
StopTimer();
mFrozen = true;
}
void
nsRefreshDriver::Thaw()
{
NS_ASSERTION(mFrozen, "Thaw called on an unfrozen refresh driver");
mFrozen = false;
if (ObserverCount() || ImageRequestCount()) {
// FIXME: This isn't quite right, since our EnsureTimerStarted call
// updates our mMostRecentRefresh, but the DoRefresh call won't run
// and notify our observers until we get back to the event loop.
// Thus MostRecentRefresh() will lie between now and the DoRefresh.
NS_DispatchToCurrentThread(NS_NewRunnableMethod(this, &nsRefreshDriver::DoRefresh));
EnsureTimerStarted(false);
}
}
void
nsRefreshDriver::SetThrottled(bool aThrottled)
{
if (aThrottled != mThrottled) {
mThrottled = aThrottled;
if (mTimer) {
// We want to switch our timer type here, so just stop and
// restart the timer.
StopTimer();
EnsureTimerStarted(true);
}
}
}
void
nsRefreshDriver::DoRefresh()
{
// Don't do a refresh unless we're in a state where we should be refreshing.
if (!mFrozen && mPresContext && mTimer) {
Notify(nsnull);
}
}
#ifdef DEBUG
bool
nsRefreshDriver::IsRefreshObserver(nsARefreshObserver *aObserver,
mozFlushType aFlushType)
{
ObserverArray& array = ArrayFor(aFlushType);
return array.Contains(aObserver);
}
#endif
void
nsRefreshDriver::ScheduleFrameRequestCallbacks(nsIDocument* aDocument)
{
NS_ASSERTION(mFrameRequestCallbackDocs.IndexOf(aDocument) ==
mFrameRequestCallbackDocs.NoIndex,
"Don't schedule the same document multiple times");
mFrameRequestCallbackDocs.AppendElement(aDocument);
// No need to worry about restarting our timer in precise mode if it's
// already running; that will happen automatically when it fires.
EnsureTimerStarted(false);
}
void
nsRefreshDriver::RevokeFrameRequestCallbacks(nsIDocument* aDocument)
{
mFrameRequestCallbackDocs.RemoveElement(aDocument);
// No need to worry about restarting our timer in slack mode if it's already
// running; that will happen automatically when it fires.
}