/*
 * 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:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * 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.
 *     * 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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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "core/loader/PrerenderHandle.h"

#include "core/dom/Document.h"
#include "core/frame/LocalFrame.h"
#include "core/loader/FrameLoader.h"
#include "core/loader/PrerendererClient.h"
#include "platform/Prerender.h"
#include "platform/weborigin/ReferrerPolicy.h"
#include "platform/weborigin/SecurityPolicy.h"

namespace blink {

// static
PrerenderHandle* PrerenderHandle::create(Document& document,
                                         PrerenderClient* client,
                                         const KURL& url,
                                         const unsigned prerenderRelTypes) {
  // Prerenders are unlike requests in most ways (for instance, they pass down
  // fragments, and they don't return data), but they do have referrers.
  if (!document.frame())
    return nullptr;

  Prerender* prerender = Prerender::create(
      client, url, prerenderRelTypes,
      SecurityPolicy::generateReferrer(document.getReferrerPolicy(), url,
                                       document.outgoingReferrer()));

  PrerendererClient* prerendererClient =
      PrerendererClient::from(document.page());
  if (prerendererClient)
    prerendererClient->willAddPrerender(prerender);
  prerender->add();

  return new PrerenderHandle(document, prerender);
}

PrerenderHandle::PrerenderHandle(Document& document, Prerender* prerender)
    : ContextLifecycleObserver(&document), m_prerender(prerender) {}

PrerenderHandle::~PrerenderHandle() {
  if (m_prerender) {
    m_prerender->abandon();
    detach();
  }
}

void PrerenderHandle::cancel() {
  // Avoid both abandoning and canceling the same prerender. In the abandon
  // case, the LinkLoader cancels the PrerenderHandle as the Document is
  // destroyed, even through the ContextLifecycleObserver has already abandoned
  // it.
  if (!m_prerender)
    return;
  m_prerender->cancel();
  detach();
}

const KURL& PrerenderHandle::url() const {
  return m_prerender->url();
}

void PrerenderHandle::contextDestroyed() {
  // A PrerenderHandle is not removed from LifecycleNotifier::m_observers until
  // the next GC runs. Thus contextDestroyed() can be called for a
  // PrerenderHandle that is already cancelled (and thus detached). In that
  // case, we should not detach the PrerenderHandle again.
  if (!m_prerender)
    return;
  m_prerender->abandon();
  detach();
}

void PrerenderHandle::detach() {
  m_prerender->dispose();
  m_prerender.clear();
}

DEFINE_TRACE(PrerenderHandle) {
  visitor->trace(m_prerender);
  ContextLifecycleObserver::trace(visitor);
}

}  // namespace blink