gecko/layout/base/nsRefreshDriver.h

160 lines
5.6 KiB
C++

/* 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.)
*/
#ifndef nsRefreshDriver_h_
#define nsRefreshDriver_h_
#include "mozilla/TimeStamp.h"
#include "mozFlushType.h"
#include "nsITimer.h"
#include "nsCOMPtr.h"
#include "nsTObserverArray.h"
class nsPresContext;
/**
* An abstract base class to be implemented by callers wanting to be
* notified at refresh times. When nothing needs to be painted, callers
* may not be notified.
*/
class nsARefreshObserver {
public:
// AddRef and Release signatures that match nsISupports. Implementors
// must implement reference counting, and those that do implement
// nsISupports will already have methods with the correct signature.
//
// The refresh driver does NOT hold references to refresh observers
// except while it is notifying them.
NS_IMETHOD_(nsrefcnt) AddRef(void) = 0;
NS_IMETHOD_(nsrefcnt) Release(void) = 0;
virtual void WillRefresh(mozilla::TimeStamp aTime) = 0;
};
class nsRefreshDriver : public nsITimerCallback {
public:
nsRefreshDriver(nsPresContext *aPresContext);
~nsRefreshDriver();
// nsISupports implementation
NS_DECL_ISUPPORTS
// nsITimerCallback implementation
NS_DECL_NSITIMERCALLBACK
/**
* Return the time of the most recent refresh. This is intended to be
* used by callers who want to start an animation now and want to know
* what time to consider the start of the animation. (This helps
* ensure that multiple animations started during the same event off
* the main event loop have the same start time.)
*/
mozilla::TimeStamp MostRecentRefresh() const;
/**
* Add / remove refresh observers. Returns whether the operation
* succeeded.
*
* The flush type affects:
* + the order in which the observers are notified (lowest flush
* type to highest, in order registered)
* + (in the future) which observers are suppressed when the display
* doesn't require current position data or isn't currently
* painting, and, correspondingly, which get notified when there
* is a flush during such suppression
* and it must be either Flush_Style, Flush_Layout, or Flush_Display.
*
* The refresh driver does NOT own a reference to these observers;
* they must remove themselves before they are destroyed.
*/
PRBool AddRefreshObserver(nsARefreshObserver *aObserver,
mozFlushType aFlushType);
PRBool RemoveRefreshObserver(nsARefreshObserver *aObserver,
mozFlushType aFlushType);
/**
* Tell the refresh driver that it is done driving refreshes and
* should stop its timer and forget about its pres context. This may
* be called from within a refresh.
*/
void Disconnect() {
StopTimer();
mPresContext = nsnull;
}
/**
* Freeze the refresh driver. It should stop delivering future
* refreshes until thawed.
*/
void Freeze();
/**
* Thaw the refresh driver. If needed, it should start delivering
* refreshes again.
*/
void Thaw();
private:
typedef nsTObserverArray<nsARefreshObserver*> ObserverArray;
void EnsureTimerStarted();
void StopTimer();
PRUint32 ObserverCount() const;
void UpdateMostRecentRefresh();
ObserverArray& ArrayFor(mozFlushType aFlushType);
// Trigger a refresh immediately, if haven't been disconnected or frozen.
void DoRefresh();
nsCOMPtr<nsITimer> mTimer;
mozilla::TimeStamp mMostRecentRefresh; // only valid when mTimer non-null
nsPresContext *mPresContext; // weak; pres context passed in constructor
// and unset in Disconnect
PRBool mFrozen;
// separate arrays for each flush type we support
ObserverArray mObservers[3];
};
#endif /* !defined(nsRefreshDriver_h_) */