gecko/layout/base/nsRefreshDriver.cpp

260 lines
7.5 KiB
C++

/* -*- 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 "nsRefreshDriver.h"
#include "nsPresContext.h"
#include "nsComponentManagerUtils.h"
#include "prlog.h"
#include "nsAutoPtr.h"
/*
* TODO:
* Once this is hooked in to suppressing updates when the presentation
* is not visible, we need to hook it up to FlushPendingNotifications so
* that we flush when necessary.
*/
#define REFRESH_INTERVAL_MILLISECONDS 20
using mozilla::TimeStamp;
nsRefreshDriver::nsRefreshDriver(nsPresContext *aPresContext)
: mPresContext(aPresContext),
mFrozen(PR_FALSE)
{
}
nsRefreshDriver::~nsRefreshDriver()
{
NS_ABORT_IF_FALSE(ObserverCount() == 0,
"observers should have unregistered");
NS_ABORT_IF_FALSE(!mTimer, "timer should be gone");
}
TimeStamp
nsRefreshDriver::MostRecentRefresh() const
{
const_cast<nsRefreshDriver*>(this)->EnsureTimerStarted();
return mMostRecentRefresh;
}
PRBool
nsRefreshDriver::AddRefreshObserver(nsARefreshObserver *aObserver,
mozFlushType aFlushType)
{
ObserverArray& array = ArrayFor(aFlushType);
PRBool success = array.AppendElement(aObserver) != nsnull;
EnsureTimerStarted();
return success;
}
PRBool
nsRefreshDriver::RemoveRefreshObserver(nsARefreshObserver *aObserver,
mozFlushType aFlushType)
{
ObserverArray& array = ArrayFor(aFlushType);
return array.RemoveElement(aObserver);
}
void
nsRefreshDriver::EnsureTimerStarted()
{
if (mTimer || mFrozen || !mPresContext) {
// It's already been started, or we don't want to start it now or
// we've been disconnected.
return;
}
UpdateMostRecentRefresh();
mTimer = do_CreateInstance(NS_TIMER_CONTRACTID);
if (!mTimer) {
return;
}
nsresult rv = mTimer->InitWithCallback(this, REFRESH_INTERVAL_MILLISECONDS,
nsITimer::TYPE_REPEATING_SLACK);
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 < NS_ARRAY_LENGTH(mObservers); ++i) {
sum += mObservers[i].Length();
}
return sum;
}
void
nsRefreshDriver::UpdateMostRecentRefresh()
{
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(PR_FALSE, "bad flush type");
return *static_cast<ObserverArray*>(nsnull);
}
}
/*
* nsISupports implementation
*/
NS_IMPL_ISUPPORTS1(nsRefreshDriver, nsITimerCallback)
/*
* nsITimerCallback implementation
*/
NS_IMETHODIMP
nsRefreshDriver::Notify(nsITimer * /* unused */)
{
NS_PRECONDITION(!mFrozen, "Why are we notified while frozen?");
NS_PRECONDITION(mPresContext, "Why are we notified after disconnection?");
UpdateMostRecentRefresh();
nsCOMPtr<nsIPresShell> presShell = mPresContext->GetPresShell();
if (!presShell || ObserverCount() == 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 < NS_ARRAY_LENGTH(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) {
// This is the Flush_Style case.
// FIXME: Maybe we should only flush if the WillRefresh calls did
// something? It's probably ok as-is, though, especially as we
// hook up more things here (or to the replacement of this class).
// FIXME: We should probably flush for other sets of observers
// too. But we should only flush layout once nsRefreshDriver is
// the driver for the interruptible layout timer (and we should
// then Flush_InterruptibleLayout).
presShell->FlushPendingNotifications(Flush_Style);
}
}
return NS_OK;
}
void
nsRefreshDriver::Freeze()
{
NS_ASSERTION(!mFrozen, "Freeze called on already-frozen refresh driver");
StopTimer();
mFrozen = PR_TRUE;
}
void
nsRefreshDriver::Thaw()
{
NS_ASSERTION(mFrozen, "Thaw called on an unfrozen refresh driver");
mFrozen = PR_FALSE;
if (ObserverCount()) {
NS_DispatchToCurrentThread(NS_NEW_RUNNABLE_METHOD(nsRefreshDriver, this,
DoRefresh));
EnsureTimerStarted();
}
}
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);
}
}