chrome/browser/prerender/prerender_histograms.h

// Copyright (c) 2012 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.

#ifndef CHROME_BROWSER_PRERENDER_PRERENDER_HISTOGRAMS_H_
#define CHROME_BROWSER_PRERENDER_PRERENDER_HISTOGRAMS_H_

#include <stddef.h>
#include <stdint.h>

#include <string>

#include "base/macros.h"
#include "base/threading/thread_checker.h"
#include "base/time/time.h"
#include "chrome/browser/prerender/prerender_contents.h"
#include "chrome/browser/prerender/prerender_final_status.h"
#include "chrome/browser/prerender/prerender_origin.h"
#include "url/gurl.h"

namespace prerender {

// Navigation type for histograms.
enum NavigationType {
  // A normal completed navigation.
  NAVIGATION_TYPE_NORMAL,
  // A completed navigation or swap that began as a prerender.
  NAVIGATION_TYPE_PRERENDERED,
};

// Records histograms for PrerenderManager.
//
// A few histograms are dynamically constructed to avoid binary size bloat from
// histogram_macros.h. Such histograms require careful handling:
// 1. slow - make sure only rare events are recorded this way, a handful of such
//    events per page load should be OK
// 2. may lead to small sporadic memory leaks in Histogram::Factory::Build() -
//    ensuring that they are recorded from the same thread is sufficient
//
// Besides thread checking this class is stateless, all public methods are
// const.
class PrerenderHistograms {
 public:
  // Owned by a PrerenderManager object for the lifetime of the
  // PrerenderManager.
  PrerenderHistograms();

  // Record that a first contentful paint occured, and whether we were able to
  // successfuly record the perceived FCP.
  void RecordPerceivedFirstContentfulPaintStatus(Origin origin,
                                                 bool successful,
                                                 bool was_hidden) const;

  // Records, in a histogram, the percentage of the page load time that had
  // elapsed by the time it is swapped in.  Values outside of [0, 1.0] are
  // invalid and ignored.
  void RecordPercentLoadDoneAtSwapin(Origin origin, double fraction) const;

  // Records the time from when a page starts prerendering to when the user
  // navigates to it. This must be called on the UI thread.
  void RecordTimeUntilUsed(Origin origin,
                           base::TimeDelta time_until_used) const;

  // Records the time from when a prerender is abandoned to when the user
  // navigates to it. This must be called on the UI thread.
  void RecordAbandonTimeUntilUsed(Origin origin,
                                  base::TimeDelta time_until_used) const;

  // Record a PerSessionCount data point.
  void RecordPerSessionCount(Origin origin, int count) const;

  // Record time between two prerender requests.
  void RecordTimeBetweenPrerenderRequests(Origin origin,
                                          base::TimeDelta time) const;

  // Record a final status of a prerendered page in a histogram.
  void RecordFinalStatus(Origin origin, FinalStatus final_status) const;

  // To be called when a new prerender is started.
  void RecordPrerenderStarted(Origin origin) const;

  // Called when we swap in a prerender.
  void RecordUsedPrerender(Origin origin) const;

  // Record the time since a page was recently visited.
  void RecordTimeSinceLastRecentVisit(Origin origin,
                                      base::TimeDelta time) const;

  // Record the bytes in the prerender, whether it was used or not, and the
  // total number of bytes fetched for this profile since the last call to
  // RecordBytes.
  void RecordNetworkBytes(Origin origin,
                          bool used,
                          int64_t prerender_bytes,
                          int64_t profile_bytes) const;

  // Called when a NoStatePrefetch request has received a response (including
  // redirects). May be called several times per resource, in case of redirects.
  void RecordPrefetchResponseReceived(Origin origin,
                                      bool is_main_resource,
                                      bool is_redirect,
                                      bool is_no_store) const;

  // Called when a NoStatePrefetch resource has been loaded. This is called only
  // once per resource, when all redirects have been resolved.
  void RecordPrefetchRedirectCount(Origin origin,
                                   bool is_main_resource,
                                   int redirect_count) const;

  // Records the time to first contentful paint with respect to a possible
  // prefetch of the page. The time to first contentful paint with respect to
  // the navigation start is recorded (even if the page was prererendered in
  // advance of navigation start). One of several histograms is used, depending
  // on whether this URL could have been prefetched before the navigation
  // leading to the paint.
  void RecordPrefetchFirstContentfulPaintTime(
      Origin origin,
      bool is_no_store,
      bool was_hidden,
      base::TimeDelta time,
      base::TimeDelta prefetch_age) const;

 private:
  base::ThreadChecker thread_checker_;

  DISALLOW_COPY_AND_ASSIGN(PrerenderHistograms);
};

}  // namespace prerender

#endif  // CHROME_BROWSER_PRERENDER_PRERENDER_HISTOGRAMS_H_