third_party/blink/renderer/core/html/custom/v0_custom_element_observer.cc

/*
 * Copyright (C) 2013 Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer
 *    in the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name of Google Inc. nor the names of its contributors
 *    may be used to endorse or promote products derived from this
 *    software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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#include "third_party/blink/renderer/core/html/custom/v0_custom_element_observer.h"

#include "third_party/blink/renderer/core/dom/element.h"
#include "third_party/blink/renderer/platform/heap/persistent.h"

namespace blink {

// Maps elements to the observer watching them. At most one per
// element at a time.
typedef HeapHashMap<WeakMember<Element>, Member<V0CustomElementObserver>>
    ElementObserverMap;

static ElementObserverMap& ElementObservers() {
  DEFINE_STATIC_LOCAL(ElementObserverMap, map, (new ElementObserverMap));
  return map;
}

void V0CustomElementObserver::NotifyElementWasDestroyed(Element* element) {
  ElementObserverMap::iterator it = ElementObservers().find(element);
  if (it == ElementObservers().end())
    return;
  it->value->ElementWasDestroyed(element);
}

void V0CustomElementObserver::Observe(Element* element) {
  ElementObserverMap::AddResult result =
      ElementObservers().insert(element, this);
  DCHECK(result.is_new_entry);
}

void V0CustomElementObserver::Unobserve(Element* element) {
  V0CustomElementObserver* observer = ElementObservers().Take(element);
  DCHECK_EQ(observer, this);
}

}  // namespace blink