third_party/blink/renderer/core/css/media_query_matcher.cc

/*
 * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Library General Public
 *  License as published by the Free Software Foundation; either
 *  version 2 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Library General Public License for more details.
 *
 *  You should have received a copy of the GNU Library General Public License
 *  along with this library; see the file COPYING.LIB.  If not, write to
 *  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 *  Boston, MA 02110-1301, USA.
 */

#include "third_party/blink/renderer/core/css/media_query_matcher.h"

#include "third_party/blink/public/common/features.h"
#include "third_party/blink/public/common/metrics/document_update_reason.h"
#include "third_party/blink/renderer/core/css/media_list.h"
#include "third_party/blink/renderer/core/css/media_query_evaluator.h"
#include "third_party/blink/renderer/core/css/media_query_list.h"
#include "third_party/blink/renderer/core/css/media_query_list_event.h"
#include "third_party/blink/renderer/core/css/media_query_list_listener.h"
#include "third_party/blink/renderer/core/css/resolver/style_resolver.h"
#include "third_party/blink/renderer/core/dom/document.h"
#include "third_party/blink/renderer/core/frame/local_frame.h"
#include "third_party/blink/renderer/core/frame/local_frame_view.h"
#include "third_party/blink/renderer/platform/wtf/vector.h"

namespace blink {

MediaQueryMatcher::MediaQueryMatcher(Document& document)
    : document_(&document) {
  DCHECK(document_);
}

MediaQueryMatcher::~MediaQueryMatcher() = default;

void MediaQueryMatcher::DocumentDetached() {
  document_ = nullptr;
  evaluator_ = nullptr;
}

MediaQueryEvaluator* MediaQueryMatcher::CreateEvaluator() const {
  if (!document_ || !document_->GetFrame()) {
    return nullptr;
  }

  return MakeGarbageCollected<MediaQueryEvaluator>(document_->GetFrame());
}

bool MediaQueryMatcher::Evaluate(const MediaQuerySet* media) {
  DCHECK(!document_ || document_->GetFrame() || !evaluator_);

  if (!media) {
    return false;
  }

  // Cache the evaluator to avoid allocating one per evaluation.
  if (!evaluator_) {
    evaluator_ = CreateEvaluator();
  }

  if (evaluator_) {
    return evaluator_->Eval(*media, &media_query_result_flags_);
  }

  return false;
}

MediaQueryList* MediaQueryMatcher::MatchMedia(const String& query) {
  if (!document_) {
    return nullptr;
  }

  // TODO(crbug.com/326992301) Check if there are other cases where we might
  // need to force layout to make the initial media-query values in sync.
  // This condition could probably be much simpler, but we are trying to
  // preserve existing (possibly buggy) behavior until the implications are
  // entirely clear.
  if (document_->IsActive() && document_->IsLoadCompleted() &&
      document_->HaveRenderBlockingStylesheetsLoaded() &&
      !document_->View()->DidFirstLayout() && !document_->LoadEventStarted() &&
      !document_->IsInMainFrame()) {
    // With the feature enabled, we skip the synchronous forced layout update
    // in Document::ImplicitClose(), so we have to force layout here to
    // compute starting values for media queries.
    DCHECK(base::FeatureList::IsEnabled(
        blink::features::kAvoidForcedLayoutOnInitialEmptyDocumentInSubframe));
    document_->UpdateStyleAndLayout(DocumentUpdateReason::kUnknown);
  }

  MediaQuerySet* media =
      MediaQuerySet::Create(query, document_->GetExecutionContext());
  return MakeGarbageCollected<MediaQueryList>(document_->GetExecutionContext(),
                                              this, media);
}

void MediaQueryMatcher::AddMediaQueryList(MediaQueryList* query) {
  if (!document_) {
    return;
  }
  media_lists_.insert(query);
}

void MediaQueryMatcher::RemoveMediaQueryList(MediaQueryList* query) {
  if (!document_) {
    return;
  }
  media_lists_.erase(query);
}

void MediaQueryMatcher::AddViewportListener(MediaQueryListListener* listener) {
  if (!document_) {
    return;
  }
  viewport_listeners_.insert(listener);
}

void MediaQueryMatcher::RemoveViewportListener(
    MediaQueryListListener* listener) {
  if (!document_) {
    return;
  }
  viewport_listeners_.erase(listener);
}

void MediaQueryMatcher::MediaFeaturesChanged() {
  if (!document_) {
    return;
  }

  // Update favicon and theme color when a media query value has changed.
  if (document_->GetFrame()) {
    document_->GetFrame()->UpdateFaviconURL();
    document_->GetFrame()->DidChangeThemeColor(
        /*update_theme_color_cache=*/false);
  }

  HeapVector<Member<MediaQueryListListener>> listeners_to_notify;
  for (const auto& list : media_lists_) {
    if (list->MediaFeaturesChanged(&listeners_to_notify)) {
      auto* event = MakeGarbageCollected<MediaQueryListEvent>(list);
      event->SetTarget(list);
      document_->EnqueueUniqueAnimationFrameEvent(event);
    }
  }
  document_->EnqueueMediaQueryChangeListeners(listeners_to_notify);
}

void MediaQueryMatcher::ViewportChanged() {
  if (!document_) {
    return;
  }

  HeapVector<Member<MediaQueryListListener>> listeners_to_notify;
  for (const auto& listener : viewport_listeners_) {
    listeners_to_notify.push_back(listener);
  }

  document_->EnqueueMediaQueryChangeListeners(listeners_to_notify);
}

void MediaQueryMatcher::DynamicViewportChanged() {
  if (media_query_result_flags_.unit_flags &
      MediaQueryExpValue::UnitFlags::kDynamicViewport) {
    ViewportChanged();
  }
}

void MediaQueryMatcher::Trace(Visitor* visitor) const {
  visitor->Trace(document_);
  visitor->Trace(evaluator_);
  visitor->Trace(media_lists_);
  visitor->Trace(viewport_listeners_);
}

}  // namespace blink