text: /*
   * Copyright (C) 2006, 2007, 2008, 2009, 2010 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/)
   * Copyright (C) 2009 Adam Barth. 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 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 "third_party/blink/renderer/core/loader/http_refresh_scheduler.h"
  
  #include <memory>
  
  #include "base/trace_event/trace_event.h"
  #include "third_party/blink/public/mojom/fetch/fetch_api_request.mojom-blink.h"
  #include "third_party/blink/public/platform/platform.h"
  #include "third_party/blink/renderer/core/events/current_input_event.h"
  #include "third_party/blink/renderer/core/frame/local_frame.h"
  #include "third_party/blink/renderer/core/loader/frame_load_request.h"
  #include "third_party/blink/renderer/core/loader/frame_loader.h"
  #include "third_party/blink/renderer/core/probe/core_probes.h"
  #include "third_party/blink/renderer/platform/scheduler/public/thread_scheduler.h"
  
  static constexpr base::TimeDelta kMaxScheduledDelay =
      base::Seconds(INT32_MAX / 1000);
  
  namespace blink {
  
  static ClientNavigationReason ToReason(
      Document::HttpRefreshType http_refresh_type) {
    switch (http_refresh_type) {
      case Document::HttpRefreshType::kHttpRefreshFromHeader:
        return ClientNavigationReason::kHttpHeaderRefresh;
      case Document::HttpRefreshType::kHttpRefreshFromMetaTag:
        return ClientNavigationReason::kMetaTagRefresh;
      default:
        break;
    }
    NOTREACHED();
    return ClientNavigationReason::kMetaTagRefresh;
  }
  
  HttpRefreshScheduler::HttpRefreshScheduler(Document* document)
      : document_(document) {}
  
  bool HttpRefreshScheduler::IsScheduledWithin(base::TimeDelta interval) const {
    return refresh_ && refresh_->delay <= interval;
  }
  
  void HttpRefreshScheduler::Schedule(
      base::TimeDelta delay,
      const KURL& url,
      Document::HttpRefreshType http_refresh_type) {
    DCHECK(document_->GetFrame());
    if (!document_->GetFrame()->IsNavigationAllowed())
      return;
    if (delay.is_negative() || delay > kMaxScheduledDelay)
      return;
    if (url.IsEmpty())
      return;
    if (refresh_ && refresh_->delay < delay)
      return;
  
    base::TimeTicks timestamp;
    if (const WebInputEvent* input_event = CurrentInputEvent::Get())
      timestamp = input_event->TimeStamp();
  
    Cancel();
    refresh_ = std::make_unique<ScheduledHttpRefresh>(
        delay, url, ToReason(http_refresh_type), timestamp);
    MaybeStartTimer();
  }
  
  void HttpRefreshScheduler::NavigateTask() {
    TRACE_EVENT2("navigation", "HttpRefreshScheduler::NavigateTask",
                 "document_url", document_->Url().GetString().Utf8(),
                 "refresh_url", refresh_->url.GetString().Utf8());
  
    DCHECK(document_->GetFrame());
    std::unique_ptr<ScheduledHttpRefresh> refresh(refresh_.release());
  
    FrameLoadRequest request(document_->domWindow(),
                             ResourceRequest(refresh->url));
    request.SetInputStartTime(refresh->input_timestamp);
    request.SetClientRedirectReason(refresh->reason);
  
    WebFrameLoadType load_type = WebFrameLoadType::kStandard;
    // If the urls match, process the refresh as a reload. However, if an initial
    // empty document has its url modified via document.open() and the refresh is
    // to that url, it will confuse the browser process to report it as a reload
    // in a frame where there hasn't actually been a navigation yet. Therefore,
    // don't treat as a reload if all this frame has ever seen is empty documents.
    if (EqualIgnoringFragmentIdentifier(document_->Url(), refresh->url) &&
        document_->GetFrame()->Loader().HasLoadedNonEmptyDocument()) {
      request.GetResourceRequest().SetCacheMode(
          mojom::FetchCacheMode::kValidateCache);
      load_type = WebFrameLoadType::kReload;
    } else if (refresh->delay <= base::Seconds(1)) {
      load_type = WebFrameLoadType::kReplaceCurrentItem;
    }
  
    document_->GetFrame()->Loader().StartNavigation(request, load_type);
    probe::FrameClearedScheduledNavigation(document_->GetFrame());
  }
  
  void HttpRefreshScheduler::MaybeStartTimer() {
    if (!refresh_)
      return;
    if (navigate_task_handle_.IsActive())
      return;
    if (!document_->LoadEventFinished())
      return;
  
    // wrapWeakPersistent(this) is safe because a posted task is canceled when the
    // task handle is destroyed on the dtor of this HttpRefreshScheduler.
    navigate_task_handle_ = PostDelayedCancellableTask(
        *document_->GetTaskRunner(TaskType::kInternalLoading), FROM_HERE,
        WTF::Bind(&HttpRefreshScheduler::NavigateTask, WrapWeakPersistent(this)),
        refresh_->delay);
  
    probe::FrameScheduledNavigation(document_->GetFrame(), refresh_->url,
                                    refresh_->delay, refresh_->reason);
  }
  
  void HttpRefreshScheduler::Cancel() {
    if (navigate_task_handle_.IsActive()) {
      probe::FrameClearedScheduledNavigation(document_->GetFrame());
    }
    navigate_task_handle_.Cancel();
    refresh_.reset();
  }
  
  void HttpRefreshScheduler::Trace(Visitor* visitor) const {
    visitor->Trace(document_);
  }
  
  }  // namespace blink
  