layout/style/MediaQueryList.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 /* implements DOM interface for querying and observing media queries */
   8
   9 #include "mozilla/dom/MediaQueryList.h"
  10 #include "mozilla/dom/MediaQueryListEvent.h"
  11 #include "mozilla/dom/MediaList.h"
  12 #include "mozilla/dom/EventTarget.h"
  13 #include "mozilla/dom/EventTargetBinding.h"
  14 #include "nsPresContext.h"
  15 #include "mozilla/dom/Document.h"
  16
  17 namespace mozilla::dom {
  18
  19 MediaQueryList::MediaQueryList(Document* aDocument,
  20                                const nsACString& aMediaQueryList,
  21                                CallerType aCallerType)
  22     : DOMEventTargetHelper(aDocument->GetInnerWindow()),
  23       mDocument(aDocument),
  24       mMediaList(MediaList::Create(aMediaQueryList, aCallerType)),
  25       mViewportDependent(mMediaList->IsViewportDependent()),
  26       mMatches(mMediaList->Matches(*aDocument)),
  27       mMatchesOnRenderingUpdate(mMatches) {
  28   KeepAliveIfHasListenersFor(nsGkAtoms::onchange);
  29 }
  30
  31 MediaQueryList::~MediaQueryList() = default;
  32
  33 NS_IMPL_CYCLE_COLLECTION_CLASS(MediaQueryList)
  34
  35 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(MediaQueryList,
  36                                                   DOMEventTargetHelper)
  37   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mDocument)
  38 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
  39
  40 NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED(MediaQueryList,
  41                                                 DOMEventTargetHelper)
  42   if (tmp->mDocument) {
  43     static_cast<LinkedListElement<MediaQueryList>*>(tmp)->remove();
  44     NS_IMPL_CYCLE_COLLECTION_UNLINK(mDocument)
  45   }
  46   tmp->Disconnect();
  47   NS_IMPL_CYCLE_COLLECTION_UNLINK_PRESERVED_WRAPPER
  48 NS_IMPL_CYCLE_COLLECTION_UNLINK_END
  49
  50 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(MediaQueryList)
  51 NS_INTERFACE_MAP_END_INHERITING(DOMEventTargetHelper)
  52
  53 NS_IMPL_ADDREF_INHERITED(MediaQueryList, DOMEventTargetHelper)
  54 NS_IMPL_RELEASE_INHERITED(MediaQueryList, DOMEventTargetHelper)
  55
  56 void MediaQueryList::GetMedia(nsACString& aMedia) const {
  57   mMediaList->GetText(aMedia);
  58 }
  59
  60 bool MediaQueryList::Matches() {
  61   if (mViewportDependent &&
  62       mDocument->StyleOrLayoutObservablyDependsOnParentDocumentLayout()) {
  63     RefPtr<Document> doc = mDocument;
  64     // This is enough to trigger media query updates in the current doc, and
  65     // will flush the parent document layout if appropriate.
  66     doc->FlushPendingNotifications(FlushType::Layout);
  67   }
  68   return mMatches;
  69 }
  70
  71 void MediaQueryList::AddListener(EventListener* aListener, ErrorResult& aRv) {
  72   if (!aListener) {
  73     return;
  74   }
  75
  76   AddEventListenerOptionsOrBoolean options;
  77   options.SetAsBoolean() = false;
  78
  79   AddEventListener(u"change"_ns, aListener, options, Nullable<bool>(), aRv);
  80 }
  81
  82 void MediaQueryList::RemoveListener(EventListener* aListener,
  83                                     ErrorResult& aRv) {
  84   if (!aListener) {
  85     return;
  86   }
  87
  88   EventListenerOptionsOrBoolean options;
  89   options.SetAsBoolean() = false;
  90
  91   RemoveEventListener(u"change"_ns, aListener, options, aRv);
  92 }
  93
  94 bool MediaQueryList::HasListeners() const {
  95   return HasListenersFor(nsGkAtoms::onchange);
  96 }
  97
  98 void MediaQueryList::Disconnect() {
  99   DisconnectFromOwner();
 100   IgnoreKeepAliveIfHasListenersFor(nsGkAtoms::onchange);
 101 }
 102
 103 nsISupports* MediaQueryList::GetParentObject() const {
 104   return ToSupports(mDocument);
 105 }
 106
 107 JSObject* MediaQueryList::WrapObject(JSContext* aCx,
 108                                      JS::Handle<JSObject*> aGivenProto) {
 109   return MediaQueryList_Binding::Wrap(aCx, this, aGivenProto);
 110 }
 111
 112 void MediaQueryList::MediaFeatureValuesChanged() {
 113   mMatches = mDocument && mMediaList->Matches(*mDocument);
 114   // Note that mMatchesOnRenderingUpdate remains with the old value here.
 115   // That gets updated in EvaluateOnRenderingUpdate().
 116 }
 117
 118 bool MediaQueryList::EvaluateOnRenderingUpdate() {
 119   if (mMatches == mMatchesOnRenderingUpdate) {
 120     return false;
 121   }
 122   mMatchesOnRenderingUpdate = mMatches;
 123   return HasListeners();
 124 }
 125
 126 void MediaQueryList::FireChangeEvent() {
 127   MediaQueryListEventInit init;
 128   init.mBubbles = false;
 129   init.mCancelable = false;
 130   init.mMatches = mMatches;
 131   mMediaList->GetText(init.mMedia);
 132
 133   RefPtr<MediaQueryListEvent> event =
 134       MediaQueryListEvent::Constructor(this, u"change"_ns, init);
 135   event->SetTrusted(true);
 136   DispatchEvent(*event);
 137 }
 138
 139 size_t MediaQueryList::SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const {
 140   size_t n = 0;
 141   // mMediaList is reference counted, but it's created and primarily owned
 142   // by this MediaQueryList object.
 143   n += mMediaList->SizeOfIncludingThis(aMallocSizeOf);
 144   return n;
 145 }
 146
 147 }  // namespace mozilla::dom