// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

/*
 * Copyright (C) 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
 * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
 * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved.
 *     (http://www.torchmobile.com/)
 *
 * 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 Apple Computer, Inc. ("Apple") 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 APPLE AND ITS 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 APPLE OR ITS 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, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "content/renderer/history_controller.h"

#include <utility>

#include "base/memory/ptr_util.h"
#include "content/common/navigation_params.h"
#include "content/common/site_isolation_policy.h"
#include "content/renderer/render_frame_impl.h"
#include "content/renderer/render_view_impl.h"
#include "third_party/WebKit/public/web/WebFrameLoadType.h"
#include "third_party/WebKit/public/web/WebLocalFrame.h"

using blink::WebCachePolicy;
using blink::WebFrame;
using blink::WebHistoryCommitType;
using blink::WebHistoryItem;
using blink::WebURLRequest;

namespace content {

HistoryController::HistoryController(RenderViewImpl* render_view)
    : render_view_(render_view) {
  // We don't use HistoryController in OOPIF enabled modes.
  DCHECK(!SiteIsolationPolicy::UseSubframeNavigationEntries());
}

HistoryController::~HistoryController() {
}

bool HistoryController::GoToEntry(
    blink::WebLocalFrame* main_frame,
    std::unique_ptr<HistoryEntry> target_entry,
    std::unique_ptr<NavigationParams> navigation_params,
    WebCachePolicy cache_policy) {
  DCHECK(!main_frame->parent());
  HistoryFrameLoadVector same_document_loads;
  HistoryFrameLoadVector different_document_loads;

  set_provisional_entry(std::move(target_entry));
  navigation_params_ = std::move(navigation_params);

  if (current_entry_) {
    RecursiveGoToEntry(
        main_frame, same_document_loads, different_document_loads);
  }

  if (same_document_loads.empty() && different_document_loads.empty()) {
    // If we don't have any frames to navigate at this point, either
    // (1) there is no previous history entry to compare against, or
    // (2) we were unable to match any frames by name. In the first case,
    // doing a different document navigation to the root item is the only valid
    // thing to do. In the second case, we should have been able to find a
    // frame to navigate based on names if this were a same document
    // navigation, so we can safely assume this is the different document case.
    different_document_loads.push_back(
        std::make_pair(main_frame, provisional_entry_->root()));
  }

  bool has_main_frame_request = false;
  for (const auto& item : same_document_loads) {
    WebFrame* frame = item.first;
    RenderFrameImpl* render_frame = RenderFrameImpl::FromWebFrame(frame);
    if (!render_frame)
      continue;
    render_frame->SetPendingNavigationParams(
        base::MakeUnique<NavigationParams>(*navigation_params_.get()));
    WebURLRequest request = frame->toWebLocalFrame()->requestFromHistoryItem(
        item.second, cache_policy);
    frame->toWebLocalFrame()->load(
        request, blink::WebFrameLoadType::BackForward, item.second,
        blink::WebHistorySameDocumentLoad);
    if (frame == main_frame)
      has_main_frame_request = true;
  }
  for (const auto& item : different_document_loads) {
    WebFrame* frame = item.first;
    RenderFrameImpl* render_frame = RenderFrameImpl::FromWebFrame(frame);
    if (!render_frame)
      continue;
    render_frame->SetPendingNavigationParams(
        base::MakeUnique<NavigationParams>(*navigation_params_.get()));
    WebURLRequest request = frame->toWebLocalFrame()->requestFromHistoryItem(
        item.second, cache_policy);
    frame->toWebLocalFrame()->load(
        request, blink::WebFrameLoadType::BackForward, item.second,
        blink::WebHistoryDifferentDocumentLoad);
    if (frame == main_frame)
      has_main_frame_request = true;
  }

  return has_main_frame_request;
}

void HistoryController::RecursiveGoToEntry(
    WebFrame* frame,
    HistoryFrameLoadVector& same_document_loads,
    HistoryFrameLoadVector& different_document_loads) {
  DCHECK(provisional_entry_);
  DCHECK(current_entry_);
  RenderFrameImpl* render_frame = RenderFrameImpl::FromWebFrame(frame);
  const WebHistoryItem& new_item =
      provisional_entry_->GetItemForFrame(render_frame);

  // Use the last committed history item for the frame rather than
  // current_entry_, since the latter may not accurately reflect which URL is
  // currently committed in the frame.  See https://crbug.com/612713#c12.
  const WebHistoryItem& old_item = render_frame->current_history_item();

  if (new_item.isNull())
    return;

  if (old_item.isNull() ||
      new_item.itemSequenceNumber() != old_item.itemSequenceNumber()) {
    if (!old_item.isNull() &&
        new_item.documentSequenceNumber() ==
            old_item.documentSequenceNumber()) {
      same_document_loads.push_back(std::make_pair(frame, new_item));

      // Returning here (and omitting child frames which have also changed) is
      // wrong, but not returning here is worse. See the discussion in
      // NavigationControllerImpl::FindFramesToNavigate for more information.
      return;
    } else {
      different_document_loads.push_back(std::make_pair(frame, new_item));
      // For a different document, the subframes will be destroyed, so there's
      // no need to consider them.
      return;
    }
  }

  for (WebFrame* child = frame->firstChild(); child;
       child = child->nextSibling()) {
    RecursiveGoToEntry(child, same_document_loads, different_document_loads);
  }
}

void HistoryController::UpdateForInitialLoadInChildFrame(
    RenderFrameImpl* frame,
    const WebHistoryItem& item) {
  DCHECK_NE(frame->GetWebFrame()->top(), frame->GetWebFrame());
  if (!current_entry_)
    return;
  if (HistoryEntry::HistoryNode* existing_node =
          current_entry_->GetHistoryNodeForFrame(frame)) {
    // Clear the children and any NavigationParams if this commit isn't for
    // the same item.  Otherwise we might have stale data after a redirect.
    if (existing_node->item().itemSequenceNumber() !=
        item.itemSequenceNumber()) {
      existing_node->RemoveChildren();
      navigation_params_.reset();
    }
    existing_node->set_item(item);
    return;
  }
  RenderFrameImpl* parent =
      RenderFrameImpl::FromWebFrame(frame->GetWebFrame()->parent());
  if (!parent)
    return;
  if (HistoryEntry::HistoryNode* parent_history_node =
          current_entry_->GetHistoryNodeForFrame(parent)) {
    parent_history_node->AddChild(item);
  }
}

void HistoryController::UpdateForCommit(RenderFrameImpl* frame,
                                        const WebHistoryItem& item,
                                        WebHistoryCommitType commit_type,
                                        bool navigation_within_page) {
  switch (commit_type) {
    case blink::WebBackForwardCommit:
      if (!provisional_entry_) {
        // The provisional entry may have been discarded due to a navigation in
        // a different frame.  For main frames, it is not safe to leave the
        // current_entry_ in place, which may have a cross-site page and will be
        // included in the PageState for this commit.  Replace it with a new
        // HistoryEntry corresponding to the commit, and clear any stale
        // NavigationParams which might point to the wrong entry.
        //
        // This will lack any subframe history items that were in the original
        // provisional entry, but we don't know what those were after discarding
        // it.  We'll load the default URL in those subframes instead.
        //
        // TODO(creis): It's also possible to get here for subframe commits.
        // We'll leave a stale current_entry_ in that case, but that only causes
        // an earlier URL to load in the subframe when leaving and coming back,
        // and only in rare cases.  It does not risk a URL spoof, unlike the
        // main frame case.  Since this bug is not present in the new
        // FrameNavigationEntry-based navigation path (https://crbug.com/236848)
        // we'll wait for that to fix the subframe case.
        if (frame->IsMainFrame()) {
          current_entry_.reset(new HistoryEntry(item));
          navigation_params_.reset();
        }

        return;
      }

      // If the current entry is null, this must be a main frame commit.
      DCHECK(current_entry_ || frame->IsMainFrame());

      // Commit the provisional entry, but only if it is a plausible transition.
      // Do not commit it if the navigation is in a subframe and the provisional
      // entry's main frame item does not match the current entry's main frame,
      // which can happen if multiple forward navigations occur.  In that case,
      // committing the provisional entry would corrupt it, leading to a URL
      // spoof.  See https://crbug.com/597322.  (Note that the race in this bug
      // does not affect main frame navigations, only navigations in subframes.)
      //
      // Note that we cannot compare the provisional entry against |item|, since
      // |item| may have redirected to a different URL and ISN.  We also cannot
      // compare against the main frame's URL, since that may have changed due
      // to a replaceState.  (Even origin can change on replaceState in certain
      // modes.)
      //
      // It would be safe to additionally check the ISNs of all parent frames
      // (and not just the root), but that is less critical because it won't
      // lead to a URL spoof.
      if (frame->IsMainFrame() ||
          current_entry_->root().itemSequenceNumber() ==
              provisional_entry_->root().itemSequenceNumber()) {
        current_entry_.reset(provisional_entry_.release());
      }

      // We're guaranteed to have a current entry now.
      DCHECK(current_entry_);

      if (HistoryEntry::HistoryNode* node =
              current_entry_->GetHistoryNodeForFrame(frame)) {
        // Clear the children and any NavigationParams if this commit isn't for
        // the same item.  Otherwise we might have stale data from a race.
        if (node->item().itemSequenceNumber() != item.itemSequenceNumber()) {
          node->RemoveChildren();
          navigation_params_.reset();
        }

        node->set_item(item);
      }
      break;
    case blink::WebStandardCommit:
      CreateNewBackForwardItem(frame, item, navigation_within_page);
      break;
    case blink::WebInitialCommitInChildFrame:
      UpdateForInitialLoadInChildFrame(frame, item);
      break;
    case blink::WebHistoryInertCommit:
      // Even for inert commits (e.g., location.replace, client redirects), make
      // sure the current entry gets updated, if there is one.
      if (current_entry_) {
        if (HistoryEntry::HistoryNode* node =
                current_entry_->GetHistoryNodeForFrame(frame)) {
          // Inert commits that reset the page without changing the item (e.g.,
          // reloads, location.replace) shouldn't keep the old subtree.
          if (!navigation_within_page)
            node->RemoveChildren();
          node->set_item(item);
        }
      }
      break;
    default:
      NOTREACHED() << "Invalid commit type: " << commit_type;
  }
}

HistoryEntry* HistoryController::GetCurrentEntry() {
  return current_entry_.get();
}

WebHistoryItem HistoryController::GetItemForNewChildFrame(
    RenderFrameImpl* frame) const {
  if (navigation_params_.get()) {
    frame->SetPendingNavigationParams(
        base::MakeUnique<NavigationParams>(*navigation_params_.get()));
  }

  if (!current_entry_)
    return WebHistoryItem();
  return current_entry_->GetItemForFrame(frame);
}

void HistoryController::RemoveChildrenForRedirect(RenderFrameImpl* frame) {
  if (!provisional_entry_)
    return;
  if (HistoryEntry::HistoryNode* node =
          provisional_entry_->GetHistoryNodeForFrame(frame))
    node->RemoveChildren();
}

void HistoryController::CreateNewBackForwardItem(
    RenderFrameImpl* target_frame,
    const WebHistoryItem& new_item,
    bool clone_children_of_target) {
  if (!current_entry_) {
    current_entry_.reset(new HistoryEntry(new_item));
  } else {
    current_entry_.reset(current_entry_->CloneAndReplace(
        new_item, clone_children_of_target, target_frame, render_view_));
  }
}

}  // namespace content