mirror of
https://github.com/mozilla/gecko-dev.git
synced 2024-10-31 22:25:30 +00:00
80 lines
2.5 KiB
C++
80 lines
2.5 KiB
C++
/* vim: set shiftwidth=2 tabstop=8 autoindent cindent expandtab: */
|
|
/* 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/. */
|
|
|
|
/* implements DOM interface for querying and observing media queries */
|
|
|
|
#ifndef nsDOMMediaQueryList_h_
|
|
#define nsDOMMediaQueryList_h_
|
|
|
|
#include "nsIDOMMediaQueryList.h"
|
|
#include "nsCycleCollectionParticipant.h"
|
|
#include "nsAutoPtr.h"
|
|
#include "nsCOMPtr.h"
|
|
#include "nsTArray.h"
|
|
#include "prclist.h"
|
|
#include "mozilla/Attributes.h"
|
|
|
|
class nsPresContext;
|
|
class nsMediaList;
|
|
|
|
class nsDOMMediaQueryList MOZ_FINAL : public nsIDOMMediaQueryList,
|
|
public PRCList
|
|
{
|
|
public:
|
|
// The caller who constructs is responsible for calling Evaluate
|
|
// before calling any other methods.
|
|
nsDOMMediaQueryList(nsPresContext *aPresContext,
|
|
const nsAString &aMediaQueryList);
|
|
private:
|
|
~nsDOMMediaQueryList();
|
|
|
|
public:
|
|
NS_DECL_CYCLE_COLLECTING_ISUPPORTS
|
|
NS_DECL_CYCLE_COLLECTION_CLASS(nsDOMMediaQueryList)
|
|
|
|
NS_DECL_NSIDOMMEDIAQUERYLIST
|
|
|
|
struct HandleChangeData {
|
|
nsRefPtr<nsDOMMediaQueryList> mql;
|
|
nsCOMPtr<nsIDOMMediaQueryListListener> listener;
|
|
};
|
|
|
|
typedef FallibleTArray< nsCOMPtr<nsIDOMMediaQueryListListener> > ListenerList;
|
|
typedef FallibleTArray<HandleChangeData> NotifyList;
|
|
|
|
// Appends listeners that need notification to aListenersToNotify
|
|
void MediumFeaturesChanged(NotifyList &aListenersToNotify);
|
|
|
|
bool HasListeners() const { return !mListeners.IsEmpty(); }
|
|
|
|
void RemoveAllListeners();
|
|
|
|
private:
|
|
void RecomputeMatches();
|
|
|
|
// We only need a pointer to the pres context to support lazy
|
|
// reevaluation following dynamic changes. However, this lazy
|
|
// reevaluation is perhaps somewhat important, since some usage
|
|
// patterns may involve the creation of large numbers of
|
|
// MediaQueryList objects which almost immediately become garbage
|
|
// (after a single call to the .matches getter).
|
|
//
|
|
// This pointer does make us a little more dependent on cycle
|
|
// collection.
|
|
//
|
|
// We have a non-null mPresContext for our entire lifetime except
|
|
// after cycle collection unlinking. Having a non-null mPresContext
|
|
// is equivalent to being in that pres context's mDOMMediaQueryLists
|
|
// linked list.
|
|
nsRefPtr<nsPresContext> mPresContext;
|
|
|
|
nsRefPtr<nsMediaList> mMediaList;
|
|
bool mMatches;
|
|
bool mMatchesValid;
|
|
ListenerList mListeners;
|
|
};
|
|
|
|
#endif /* !defined(nsDOMMediaQueryList_h_) */
|