third_party/WebKit/Source/web/ContextFeaturesClientImpl.cpp

/*
 * Copyright (C) 2012 Google Inc. All rights reserved.
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 * modification, are permitted provided that the following conditions are
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 * in the documentation and/or other materials provided with the
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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#include "web/ContextFeaturesClientImpl.h"

#include "core/dom/Document.h"
#include "platform/weborigin/SecurityOrigin.h"
#include "public/web/WebContentSettingsClient.h"
#include "public/web/WebDocument.h"
#include "web/WebLocalFrameImpl.h"

namespace blink {

class ContextFeaturesCache final
    : public GarbageCollectedFinalized<ContextFeaturesCache>,
      public Supplement<Document> {
  USING_GARBAGE_COLLECTED_MIXIN(ContextFeaturesCache);

 public:
  class Entry {
   public:
    enum Value { IsEnabled, IsDisabled, NeedsRefresh };

    Entry() : m_value(NeedsRefresh), m_defaultValue(false) {}

    bool isEnabled() const {
      DCHECK_NE(m_value, NeedsRefresh);
      return m_value == IsEnabled;
    }

    void set(bool value, bool defaultValue) {
      m_value = value ? IsEnabled : IsDisabled;
      m_defaultValue = defaultValue;
    }

    bool needsRefresh(bool defaultValue) const {
      return m_value == NeedsRefresh || m_defaultValue != defaultValue;
    }

   private:
    Value m_value;
    bool m_defaultValue;  // Needs to be traked as a part of the signature since
                          // it can be changed dynamically.
  };

  static const char* supplementName();
  static ContextFeaturesCache& from(Document&);

  Entry& entryFor(ContextFeatures::FeatureType type) {
    size_t index = static_cast<size_t>(type);
    SECURITY_DCHECK(index < ContextFeatures::FeatureTypeSize);
    return m_entries[index];
  }

  void validateAgainst(Document*);

  DEFINE_INLINE_VIRTUAL_TRACE() { Supplement<Document>::trace(visitor); }

 private:
  explicit ContextFeaturesCache(Document& document)
      : Supplement<Document>(document) {}

  String m_domain;
  Entry m_entries[ContextFeatures::FeatureTypeSize];
};

const char* ContextFeaturesCache::supplementName() {
  return "ContextFeaturesCache";
}

ContextFeaturesCache& ContextFeaturesCache::from(Document& document) {
  ContextFeaturesCache* cache = static_cast<ContextFeaturesCache*>(
      Supplement<Document>::from(document, supplementName()));
  if (!cache) {
    cache = new ContextFeaturesCache(document);
    Supplement<Document>::provideTo(document, supplementName(), cache);
  }

  return *cache;
}

void ContextFeaturesCache::validateAgainst(Document* document) {
  String currentDomain = document->getSecurityOrigin()->domain();
  if (currentDomain == m_domain)
    return;
  m_domain = currentDomain;
  for (size_t i = 0; i < ContextFeatures::FeatureTypeSize; ++i)
    m_entries[i] = Entry();
}

bool ContextFeaturesClientImpl::isEnabled(Document* document,
                                          ContextFeatures::FeatureType type,
                                          bool defaultValue) {
  DCHECK(document);
  ContextFeaturesCache::Entry& cache =
      ContextFeaturesCache::from(*document).entryFor(type);
  if (cache.needsRefresh(defaultValue))
    cache.set(askIfIsEnabled(document, type, defaultValue), defaultValue);
  return cache.isEnabled();
}

void ContextFeaturesClientImpl::urlDidChange(Document* document) {
  DCHECK(document);
  ContextFeaturesCache::from(*document).validateAgainst(document);
}

bool ContextFeaturesClientImpl::askIfIsEnabled(
    Document* document,
    ContextFeatures::FeatureType type,
    bool defaultValue) {
  WebLocalFrameImpl* frame = WebLocalFrameImpl::fromFrame(document->frame());
  if (!frame || !frame->contentSettingsClient())
    return defaultValue;

  switch (type) {
    case ContextFeatures::MutationEvents:
      return frame->contentSettingsClient()->allowMutationEvents(defaultValue);
    default:
      return defaultValue;
  }
}

}  // namespace blink