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authorMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
committerMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
commit5f8de423f190bbb79a62f804151bc24824fa32d8 (patch)
tree10027f336435511475e392454359edea8e25895d /layout/style/MediaQueryList.h
parent49ee0794b5d912db1f95dce6eb52d781dc210db5 (diff)
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Add m-esr52 at 52.6.0
Diffstat (limited to 'layout/style/MediaQueryList.h')
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diff --git a/layout/style/MediaQueryList.h b/layout/style/MediaQueryList.h
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+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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 mozilla_dom_MediaQueryList_h
+#define mozilla_dom_MediaQueryList_h
+
+#include "nsISupports.h"
+#include "nsCycleCollectionParticipant.h"
+#include "nsCOMPtr.h"
+#include "nsTArray.h"
+#include "prclist.h"
+#include "mozilla/Attributes.h"
+#include "nsWrapperCache.h"
+#include "mozilla/dom/MediaQueryListBinding.h"
+
+class nsIDocument;
+class nsMediaList;
+
+namespace mozilla {
+namespace dom {
+
+class MediaQueryList final : public nsISupports,
+ public nsWrapperCache,
+ public PRCList
+{
+public:
+ // The caller who constructs is responsible for calling Evaluate
+ // before calling any other methods.
+ MediaQueryList(nsIDocument *aDocument,
+ const nsAString &aMediaQueryList);
+private:
+ ~MediaQueryList();
+
+public:
+ NS_DECL_CYCLE_COLLECTING_ISUPPORTS
+ NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(MediaQueryList)
+
+ nsISupports* GetParentObject() const;
+
+ struct HandleChangeData {
+ RefPtr<MediaQueryList> mql;
+ RefPtr<mozilla::dom::MediaQueryListListener> callback;
+ };
+
+ // Appends listeners that need notification to aListenersToNotify
+ void MediumFeaturesChanged(nsTArray<HandleChangeData>& aListenersToNotify);
+
+ bool HasListeners() const { return !mCallbacks.IsEmpty(); }
+
+ void RemoveAllListeners();
+
+ JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;
+
+ // WebIDL methods
+ void GetMedia(nsAString& aMedia);
+ bool Matches();
+ void AddListener(mozilla::dom::MediaQueryListListener& aListener);
+ void RemoveListener(mozilla::dom::MediaQueryListListener& aListener);
+
+private:
+ void RecomputeMatches();
+
+ // We only need a pointer to the document 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 mDocument for our entire lifetime except
+ // after cycle collection unlinking. Having a non-null mDocument
+ // is equivalent to being in that document's mDOMMediaQueryLists
+ // linked list.
+ nsCOMPtr<nsIDocument> mDocument;
+
+ RefPtr<nsMediaList> mMediaList;
+ bool mMatches;
+ bool mMatchesValid;
+ nsTArray<RefPtr<mozilla::dom::MediaQueryListListener>> mCallbacks;
+};
+
+} // namespace dom
+} // namespace mozilla
+
+#endif /* !defined(mozilla_dom_MediaQueryList_h) */