зеркало из https://github.com/mozilla/pjs.git
111 строки
4.0 KiB
C++
111 строки
4.0 KiB
C++
/* vim: set shiftwidth=2 tabstop=8 autoindent cindent expandtab: */
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/* ***** BEGIN LICENSE BLOCK *****
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* Version: MPL 1.1/GPL 2.0/LGPL 2.1
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*
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* The contents of this file are subject to the Mozilla Public License Version
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* 1.1 (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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* for the specific language governing rights and limitations under the
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* License.
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*
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* The Original Code is nsDOMMediaQueryList.
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*
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* The Initial Developer of the Original Code is the Mozilla Foundation.
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* Portions created by the Initial Developer are Copyright (C) 2011
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* the Initial Developer. All Rights Reserved.
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*
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* Contributor(s):
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* L. David Baron <dbaron@dbaron.org>, Mozilla Corporation (original author)
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*
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* Alternatively, the contents of this file may be used under the terms of
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* either the GNU General Public License Version 2 or later (the "GPL"), or
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* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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* in which case the provisions of the GPL or the LGPL are applicable instead
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* of those above. If you wish to allow use of your version of this file only
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* under the terms of either the GPL or the LGPL, and not to allow others to
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* use your version of this file under the terms of the MPL, indicate your
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* decision by deleting the provisions above and replace them with the notice
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* and other provisions required by the GPL or the LGPL. If you do not delete
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* the provisions above, a recipient may use your version of this file under
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* the terms of any one of the MPL, the GPL or the LGPL.
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*
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* ***** END LICENSE BLOCK ***** */
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/* implements DOM interface for querying and observing media queries */
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#ifndef nsDOMMediaQueryList_h_
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#define nsDOMMediaQueryList_h_
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#include "nsIDOMMediaQueryList.h"
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#include "nsCycleCollectionParticipant.h"
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#include "nsAutoPtr.h"
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#include "nsCOMPtr.h"
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#include "nsTArray.h"
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#include "prclist.h"
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class nsPresContext;
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class nsMediaList;
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class nsDOMMediaQueryList : public nsIDOMMediaQueryList,
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public PRCList
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{
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public:
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// The caller who constructs is responsible for calling Evaluate
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// before calling any other methods.
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nsDOMMediaQueryList(nsPresContext *aPresContext,
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const nsAString &aMediaQueryList);
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private:
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~nsDOMMediaQueryList();
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public:
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NS_DECL_CYCLE_COLLECTING_ISUPPORTS
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NS_DECL_CYCLE_COLLECTION_CLASS(nsDOMMediaQueryList)
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NS_DECL_NSIDOMMEDIAQUERYLIST
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struct HandleChangeData {
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nsRefPtr<nsDOMMediaQueryList> mql;
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nsCOMPtr<nsIDOMMediaQueryListListener> listener;
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};
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typedef FallibleTArray< nsCOMPtr<nsIDOMMediaQueryListListener> > ListenerList;
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typedef FallibleTArray<HandleChangeData> NotifyList;
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// Appends listeners that need notification to aListenersToNotify
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void MediumFeaturesChanged(NotifyList &aListenersToNotify);
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bool HasListeners() const { return !mListeners.IsEmpty(); }
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void RemoveAllListeners();
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private:
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void RecomputeMatches();
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// We only need a pointer to the pres context to support lazy
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// reevaluation following dynamic changes. However, this lazy
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// reevaluation is perhaps somewhat important, since some usage
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// patterns may involve the creation of large numbers of
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// MediaQueryList objects which almost immediately become garbage
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// (after a single call to the .matches getter).
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//
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// This pointer does make us a little more dependent on cycle
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// collection.
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//
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// We have a non-null mPresContext for our entire lifetime except
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// after cycle collection unlinking. Having a non-null mPresContext
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// is equivalent to being in that pres context's mDOMMediaQueryLists
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// linked list.
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nsRefPtr<nsPresContext> mPresContext;
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nsRefPtr<nsMediaList> mMediaList;
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bool mMatches;
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bool mMatchesValid;
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ListenerList mListeners;
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};
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#endif /* !defined(nsDOMMediaQueryList_h_) */
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