components/security_interstitials/core/metrics_helper.h

// Copyright 2015 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 COMPONENTS_SECURITY_INTERSTITIALS_CORE_METRICS_HELPER_H_
#define COMPONENTS_SECURITY_INTERSTITIALS_CORE_METRICS_HELPER_H_

#include <string>

#include "base/macros.h"
#include "base/memory/weak_ptr.h"
#include "base/task/cancelable_task_tracker.h"
#include "base/time/time.h"
#include "url/gurl.h"

namespace history {
class HistoryService;
}

namespace security_interstitials {

// MetricsHelper records user warning interactions in a common way via METRICS
// histograms. The class will generate the following histograms:
//   METRICS: interstitial.<metric_prefix>.decision[.repeat_visit]
//   METRICS: interstitial.<metric_prefix>.interaction[.repeat_visit]
// wherein |metric_prefix| is specified via ReportDetails.
// repeat_visit is also generated if the user has seen the page before.
//
// If |extra_suffix| is not empty, MetricsHelper will append ".<extra_suffix>"
// to generate an additional 2 or 4 more metrics.
class MetricsHelper {
 public:
  // These enums are used for histograms.  Don't reorder, delete, or insert
  // elements. New elements should be added at the end (right before the max).
  enum Decision {
    SHOW,
    PROCEED,
    DONT_PROCEED,
    PROCEEDING_DISABLED,
    MAX_DECISION
  };
  enum Interaction {
    TOTAL_VISITS,
    SHOW_ADVANCED,
    SHOW_PRIVACY_POLICY,
    SHOW_DIAGNOSTIC,
    SHOW_LEARN_MORE,
    RELOAD,
    OPEN_TIME_SETTINGS,
    SET_EXTENDED_REPORTING_ENABLED,
    SET_EXTENDED_REPORTING_DISABLED,
    EXTENDED_REPORTING_IS_ENABLED,
    REPORT_PHISHING_ERROR,
    SHOW_WHITEPAPER,
    MAX_INTERACTION
  };

  // metric_prefix: Histogram prefix for UMA.
  //                examples: "phishing", "ssl_overridable"
  // extra_suffix: If not-empty, will generate second set of metrics by
  //               placing at the end of the metric name.  Examples:
  //               "from_datasaver", "from_device"
  struct ReportDetails {
    ReportDetails();
    ReportDetails(const ReportDetails& other);
    ~ReportDetails();
    std::string metric_prefix;
    std::string extra_suffix;
  };

  // Args:
  //   url: URL of page that triggered the interstitial. Only origin is used.
  //   history_service: Set this to record metrics based on whether the user
  //                    has visited this hostname before.
  //   settings: Specify reporting details (prefixes and report types).
  //   sampling_event_name: Event name for Experience Sampling.
  //                        e.g. "phishing_interstitial_"
  MetricsHelper(const GURL& url,
                const ReportDetails settings,
                history::HistoryService* history_service);
  virtual ~MetricsHelper();

  // Records a user decision or interaction to the appropriate UMA metrics
  // histogram.
  void RecordUserDecision(Decision decision);
  void RecordUserInteraction(Interaction interaction);
  void RecordShutdownMetrics();

  // Number of times user visited this origin before. -1 means not-yet-set.
  int NumVisits();

 protected:
  // Subclasses should implement any embedder-specific recording logic in these
  // methods. They'll be invoked from the matching Record methods.
  virtual void RecordExtraUserDecisionMetrics(Decision decision);
  virtual void RecordExtraUserInteractionMetrics(Interaction interaction);
  virtual void RecordExtraShutdownMetrics();

 private:
  // Used to query the HistoryService to see if the URL is in history.  It will
  // only be invoked if the constructor received |history_service|.
  void OnGotHistoryCount(bool success, int num_visits, base::Time first_visit);

  void RecordUserDecisionToMetrics(Decision decision,
                                   const std::string& histogram_name);
  const GURL request_url_;
  const ReportDetails settings_;
  int num_visits_;
  base::CancelableTaskTracker request_tracker_;

  DISALLOW_COPY_AND_ASSIGN(MetricsHelper);
};

}  // namespace security_interstitials

#endif  // COMPONENTS_SECURITY_INTERSTITIALS_CORE_METRICS_HELPER_H_