/*
 * Copyright (C) 1998, 1999 Torben Weis <weis@kde.org>
 *                     1999 Lars Knoll <knoll@kde.org>
 *                     1999 Antti Koivisto <koivisto@kde.org>
 *                     2000 Simon Hausmann <hausmann@kde.org>
 *                     2000 Stefan Schimanski <1Stein@gmx.de>
 *                     2001 George Staikos <staikos@kde.org>
 * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All
 * rights reserved.
 * Copyright (C) 2005 Alexey Proskuryakov <ap@nypop.com>
 * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
 * Copyright (C) 2008 Eric Seidel <eric@webkit.org>
 * Copyright (C) 2008 Google Inc.
 *
 * 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 "core/frame/Frame.h"

#include "core/dom/DocumentType.h"
#include "core/events/Event.h"
#include "core/frame/FrameHost.h"
#include "core/frame/LocalDOMWindow.h"
#include "core/frame/Settings.h"
#include "core/frame/UseCounter.h"
#include "core/html/HTMLFrameElementBase.h"
#include "core/input/EventHandler.h"
#include "core/inspector/InspectorInstrumentation.h"
#include "core/inspector/InstanceCounters.h"
#include "core/layout/LayoutPart.h"
#include "core/layout/api/LayoutPartItem.h"
#include "core/loader/EmptyClients.h"
#include "core/loader/FrameLoaderClient.h"
#include "core/loader/NavigationScheduler.h"
#include "core/page/FocusController.h"
#include "core/page/Page.h"
#include "platform/Histogram.h"
#include "platform/UserGestureIndicator.h"

namespace blink {

using namespace HTMLNames;

Frame::~Frame() {
  InstanceCounters::decrementCounter(InstanceCounters::FrameCounter);
  ASSERT(!m_owner);
}

DEFINE_TRACE(Frame) {
  visitor->trace(m_treeNode);
  visitor->trace(m_host);
  visitor->trace(m_owner);
  visitor->trace(m_client);
}

void Frame::detach(FrameDetachType type) {
  ASSERT(m_client);
  m_client->setOpener(0);
  domWindow()->resetLocation();
  disconnectOwnerElement();
  // After this, we must no longer talk to the client since this clears
  // its owning reference back to our owning LocalFrame.
  m_client->detached(type);
  m_client = nullptr;
  m_host = nullptr;
}

void Frame::disconnectOwnerElement() {
  if (m_owner) {
    m_owner->clearContentFrame();
    m_owner = nullptr;
  }
}

Page* Frame::page() const {
  if (m_host)
    return &m_host->page();
  return nullptr;
}

FrameHost* Frame::host() const {
  return m_host;
}

bool Frame::isMainFrame() const {
  return !tree().parent();
}

bool Frame::isLocalRoot() const {
  if (isRemoteFrame())
    return false;

  if (!tree().parent())
    return true;

  return tree().parent()->isRemoteFrame();
}

HTMLFrameOwnerElement* Frame::deprecatedLocalOwner() const {
  return m_owner && m_owner->isLocal() ? toHTMLFrameOwnerElement(m_owner)
                                       : nullptr;
}

static ChromeClient& emptyChromeClient() {
  DEFINE_STATIC_LOCAL(EmptyChromeClient, client, (EmptyChromeClient::create()));
  return client;
}

ChromeClient& Frame::chromeClient() const {
  if (Page* page = this->page())
    return page->chromeClient();
  return emptyChromeClient();
}

Frame* Frame::findFrameForNavigation(const AtomicString& name,
                                     Frame& activeFrame) {
  Frame* frame = tree().find(name);
  if (!frame || !activeFrame.canNavigate(*frame))
    return nullptr;
  return frame;
}

static bool canAccessAncestor(const SecurityOrigin& activeSecurityOrigin,
                              const Frame* targetFrame) {
  // targetFrame can be 0 when we're trying to navigate a top-level frame
  // that has a 0 opener.
  if (!targetFrame)
    return false;

  const bool isLocalActiveOrigin = activeSecurityOrigin.isLocal();
  for (const Frame* ancestorFrame = targetFrame; ancestorFrame;
       ancestorFrame = ancestorFrame->tree().parent()) {
    const SecurityOrigin* ancestorSecurityOrigin =
        ancestorFrame->securityContext()->getSecurityOrigin();
    if (activeSecurityOrigin.canAccess(ancestorSecurityOrigin))
      return true;

    // Allow file URL descendant navigation even when
    // allowFileAccessFromFileURLs is false.
    // FIXME: It's a bit strange to special-case local origins here. Should we
    // be doing something more general instead?
    if (isLocalActiveOrigin && ancestorSecurityOrigin->isLocal())
      return true;
  }

  return false;
}

bool Frame::canNavigate(const Frame& targetFrame) {
  String errorReason;
  bool isAllowedNavigation =
      canNavigateWithoutFramebusting(targetFrame, errorReason);

  if (targetFrame != this &&
      !securityContext()->isSandboxed(SandboxTopNavigation) &&
      targetFrame == tree().top()) {
    DEFINE_STATIC_LOCAL(EnumerationHistogram, framebustHistogram,
                        ("WebCore.Framebust", 4));
    const unsigned userGestureBit = 0x1;
    const unsigned allowedBit = 0x2;
    unsigned framebustParams = 0;
    UseCounter::count(&targetFrame, UseCounter::TopNavigationFromSubFrame);
    bool hasUserGesture = UserGestureIndicator::processingUserGesture();
    if (hasUserGesture)
      framebustParams |= userGestureBit;
    if (isAllowedNavigation)
      framebustParams |= allowedBit;
    framebustHistogram.count(framebustParams);
    // Frame-busting used to be generally allowed in most situations, but may
    // now blocked if there is no user gesture.
    if (!RuntimeEnabledFeatures::
            framebustingNeedsSameOriginOrUserGestureEnabled())
      return true;
    if (hasUserGesture || isAllowedNavigation)
      return true;
    errorReason =
        "The frame attempting navigation is targeting its top-level window, "
        "but is neither same-origin with its target nor is it processing a "
        "user gesture. See "
        "https://www.chromestatus.com/features/5851021045661696.";
    printNavigationErrorMessage(targetFrame, errorReason.latin1().data());
    if (isLocalFrame())
      toLocalFrame(this)->navigationScheduler().schedulePageBlock(
          toLocalFrame(this)->document());
    return false;
  }
  if (!isAllowedNavigation && !errorReason.isNull())
    printNavigationErrorMessage(targetFrame, errorReason.latin1().data());
  return isAllowedNavigation;
}

bool Frame::canNavigateWithoutFramebusting(const Frame& targetFrame,
                                           String& reason) {
  if (securityContext()->isSandboxed(SandboxNavigation)) {
    // Sandboxed frames can navigate their own children.
    if (targetFrame.tree().isDescendantOf(this))
      return true;

    // They can also navigate popups, if the 'allow-sandbox-escape-via-popup'
    // flag is specified.
    if (targetFrame == targetFrame.tree().top() &&
        targetFrame.tree().top() != tree().top() &&
        !securityContext()->isSandboxed(
            SandboxPropagatesToAuxiliaryBrowsingContexts))
      return true;

    // Top navigation can be opted-in.
    if (!securityContext()->isSandboxed(SandboxTopNavigation) &&
        targetFrame == tree().top())
      return true;

    // Otherwise, block the navigation.
    if (securityContext()->isSandboxed(SandboxTopNavigation) &&
        targetFrame == tree().top())
      reason =
          "The frame attempting navigation of the top-level window is "
          "sandboxed, but the 'allow-top-navigation' flag is not set.";
    else
      reason =
          "The frame attempting navigation is sandboxed, and is therefore "
          "disallowed from navigating its ancestors.";
    return false;
  }

  ASSERT(securityContext()->getSecurityOrigin());
  SecurityOrigin& origin = *securityContext()->getSecurityOrigin();

  // This is the normal case. A document can navigate its decendant frames,
  // or, more generally, a document can navigate a frame if the document is
  // in the same origin as any of that frame's ancestors (in the frame
  // hierarchy).
  //
  // See http://www.adambarth.com/papers/2008/barth-jackson-mitchell.pdf for
  // historical information about this security check.
  if (canAccessAncestor(origin, &targetFrame))
    return true;

  // Top-level frames are easier to navigate than other frames because they
  // display their URLs in the address bar (in most browsers). However, there
  // are still some restrictions on navigation to avoid nuisance attacks.
  // Specifically, a document can navigate a top-level frame if that frame
  // opened the document or if the document is the same-origin with any of
  // the top-level frame's opener's ancestors (in the frame hierarchy).
  //
  // In both of these cases, the document performing the navigation is in
  // some way related to the frame being navigate (e.g., by the "opener"
  // and/or "parent" relation). Requiring some sort of relation prevents a
  // document from navigating arbitrary, unrelated top-level frames.
  if (!targetFrame.tree().parent()) {
    if (targetFrame == client()->opener())
      return true;
    if (canAccessAncestor(origin, targetFrame.client()->opener()))
      return true;
  }

  reason =
      "The frame attempting navigation is neither same-origin with the target, "
      "nor is it the target's parent or opener.";
  return false;
}

Frame* Frame::findUnsafeParentScrollPropagationBoundary() {
  Frame* currentFrame = this;
  Frame* ancestorFrame = tree().parent();

  while (ancestorFrame) {
    if (!ancestorFrame->securityContext()->getSecurityOrigin()->canAccess(
            securityContext()->getSecurityOrigin()))
      return currentFrame;
    currentFrame = ancestorFrame;
    ancestorFrame = ancestorFrame->tree().parent();
  }
  return nullptr;
}

LayoutPart* Frame::ownerLayoutObject() const {
  if (!deprecatedLocalOwner())
    return nullptr;
  LayoutObject* object = deprecatedLocalOwner()->layoutObject();
  if (!object)
    return nullptr;
  // FIXME: If <object> is ever fixed to disassociate itself from frames
  // that it has started but canceled, then this can turn into an ASSERT
  // since ownerElement() would be 0 when the load is canceled.
  // https://bugs.webkit.org/show_bug.cgi?id=18585
  if (!object->isLayoutPart())
    return nullptr;
  return toLayoutPart(object);
}

LayoutPartItem Frame::ownerLayoutItem() const {
  return LayoutPartItem(ownerLayoutObject());
}

Settings* Frame::settings() const {
  if (m_host)
    return &m_host->settings();
  return nullptr;
}

void Frame::didChangeVisibilityState() {
  HeapVector<Member<Frame>> childFrames;
  for (Frame* child = tree().firstChild(); child;
       child = child->tree().nextSibling())
    childFrames.append(child);
  for (size_t i = 0; i < childFrames.size(); ++i)
    childFrames[i]->didChangeVisibilityState();
}

Frame::Frame(FrameClient* client, FrameHost* host, FrameOwner* owner)
    : m_treeNode(this),
      m_host(host),
      m_owner(owner),
      m_client(client),
      m_isLoading(false) {
  InstanceCounters::incrementCounter(InstanceCounters::FrameCounter);

  ASSERT(page());

  if (m_owner)
    m_owner->setContentFrame(*this);
  else
    page()->setMainFrame(this);
}

}  // namespace blink