1 files changed, 147 insertions, 0 deletions
diff --git a/layout/style/MediaQueryList.cpp b/layout/style/MediaQueryList.cpp
new file mode 100644
index 0000000000..b0d0586248
--- /dev/null
+++ b/layout/style/MediaQueryList.cpp
@@ -0,0 +1,147 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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 */
+
+#include "mozilla/dom/MediaQueryList.h"
+#include "mozilla/dom/MediaQueryListEvent.h"
+#include "mozilla/dom/MediaList.h"
+#include "mozilla/dom/EventTarget.h"
+#include "mozilla/dom/EventTargetBinding.h"
+#include "nsPresContext.h"
+#include "mozilla/dom/Document.h"
+
+namespace mozilla::dom {
+
+MediaQueryList::MediaQueryList(Document* aDocument,
+                               const nsACString& aMediaQueryList,
+                               CallerType aCallerType)
+    : DOMEventTargetHelper(aDocument->GetInnerWindow()),
+      mDocument(aDocument),
+      mMediaList(MediaList::Create(aMediaQueryList, aCallerType)),
+      mViewportDependent(mMediaList->IsViewportDependent()),
+      mMatches(mMediaList->Matches(*aDocument)),
+      mMatchesOnRenderingUpdate(mMatches) {
+  KeepAliveIfHasListenersFor(nsGkAtoms::onchange);
+}
+
+MediaQueryList::~MediaQueryList() = default;
+
+NS_IMPL_CYCLE_COLLECTION_CLASS(MediaQueryList)
+
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(MediaQueryList,
+                                                  DOMEventTargetHelper)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mDocument)
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
+
+NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED(MediaQueryList,
+                                                DOMEventTargetHelper)
+  if (tmp->mDocument) {
+    static_cast<LinkedListElement<MediaQueryList>*>(tmp)->remove();
+    NS_IMPL_CYCLE_COLLECTION_UNLINK(mDocument)
+  }
+  tmp->Disconnect();
+  NS_IMPL_CYCLE_COLLECTION_UNLINK_PRESERVED_WRAPPER
+NS_IMPL_CYCLE_COLLECTION_UNLINK_END
+
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(MediaQueryList)
+NS_INTERFACE_MAP_END_INHERITING(DOMEventTargetHelper)
+
+NS_IMPL_ADDREF_INHERITED(MediaQueryList, DOMEventTargetHelper)
+NS_IMPL_RELEASE_INHERITED(MediaQueryList, DOMEventTargetHelper)
+
+void MediaQueryList::GetMedia(nsACString& aMedia) const {
+  mMediaList->GetText(aMedia);
+}
+
+bool MediaQueryList::Matches() {
+  if (mViewportDependent &&
+      mDocument->StyleOrLayoutObservablyDependsOnParentDocumentLayout()) {
+    RefPtr<Document> doc = mDocument;
+    // This is enough to trigger media query updates in the current doc, and
+    // will flush the parent document layout if appropriate.
+    doc->FlushPendingNotifications(FlushType::Layout);
+  }
+  return mMatches;
+}
+
+void MediaQueryList::AddListener(EventListener* aListener, ErrorResult& aRv) {
+  if (!aListener) {
+    return;
+  }
+
+  AddEventListenerOptionsOrBoolean options;
+  options.SetAsBoolean() = false;
+
+  AddEventListener(u"change"_ns, aListener, options, Nullable<bool>(), aRv);
+}
+
+void MediaQueryList::RemoveListener(EventListener* aListener,
+                                    ErrorResult& aRv) {
+  if (!aListener) {
+    return;
+  }
+
+  EventListenerOptionsOrBoolean options;
+  options.SetAsBoolean() = false;
+
+  RemoveEventListener(u"change"_ns, aListener, options, aRv);
+}
+
+bool MediaQueryList::HasListeners() const {
+  return HasListenersFor(nsGkAtoms::onchange);
+}
+
+void MediaQueryList::Disconnect() {
+  DisconnectFromOwner();
+  IgnoreKeepAliveIfHasListenersFor(nsGkAtoms::onchange);
+}
+
+nsISupports* MediaQueryList::GetParentObject() const {
+  return ToSupports(mDocument);
+}
+
+JSObject* MediaQueryList::WrapObject(JSContext* aCx,
+                                     JS::Handle<JSObject*> aGivenProto) {
+  return MediaQueryList_Binding::Wrap(aCx, this, aGivenProto);
+}
+
+void MediaQueryList::MediaFeatureValuesChanged() {
+  mMatches = mDocument && mMediaList->Matches(*mDocument);
+  // Note that mMatchesOnRenderingUpdate remains with the old value here.
+  // That gets updated in EvaluateOnRenderingUpdate().
+}
+
+bool MediaQueryList::EvaluateOnRenderingUpdate() {
+  if (mMatches == mMatchesOnRenderingUpdate) {
+    return false;
+  }
+  mMatchesOnRenderingUpdate = mMatches;
+  return HasListeners();
+}
+
+void MediaQueryList::FireChangeEvent() {
+  MediaQueryListEventInit init;
+  init.mBubbles = false;
+  init.mCancelable = false;
+  init.mMatches = mMatches;
+  mMediaList->GetText(init.mMedia);
+
+  RefPtr<MediaQueryListEvent> event =
+      MediaQueryListEvent::Constructor(this, u"change"_ns, init);
+  event->SetTrusted(true);
+  DispatchEvent(*event);
+}
+
+size_t MediaQueryList::SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const {
+  size_t n = 0;
+  // mMediaList is reference counted, but it's created and primarily owned
+  // by this MediaQueryList object.
+  n += mMediaList->SizeOfIncludingThis(aMallocSizeOf);
+  return n;
+}
+
+}  // namespace mozilla::dom