base/metrics/user_metrics.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef BASE_METRICS_USER_METRICS_H_
   6 #define BASE_METRICS_USER_METRICS_H_
   7
   8 #include <string>
   9
  10 #include "base/base_export.h"
  11 #include "base/callback.h"
  12 #include "base/metrics/user_metrics_action.h"
  13
  14 namespace base {
  15
  16 // This module provides some helper functions for logging actions tracked by
  17 // the user metrics system.
  18
  19 // Record that the user performed an action.
  20 // "Action" here means a user-generated event:
  21 //   good: "Reload", "CloseTab", and "IMEInvoked"
  22 //   not good: "SSLDialogShown", "PageLoaded", "DiskFull"
  23 // We use this to gather anonymized information about how users are
  24 // interacting with the browser.
  25 // WARNING: In calls to this function, UserMetricsAction and a
  26 // string literal parameter must be on the same line, e.g.
  27 //   RecordAction(UserMetricsAction("my extremely long action name"));
  28 // This ensures that our processing scripts can associate this action's hash
  29 // with its metric name. Therefore, it will be possible to retrieve the metric
  30 // name from the hash later on.
  31 //
  32 // Once a new recorded action is added, run
  33 // tools/metrics/actions/extract_actions.py --hash
  34 // to generate a new mapping of [action hashes -> metric names] and send it
  35 // out for review to be updated.
  36 //
  37 // For more complicated situations (like when there are many different
  38 // possible actions), see RecordComputedAction.
  39 BASE_EXPORT void RecordAction(const UserMetricsAction& action);
  40
  41 // This function has identical input and behavior to RecordAction, but is
  42 // not automatically found by the action-processing scripts.  It can be used
  43 // when it's a pain to enumerate all possible actions, but if you use this
  44 // you need to also update the rules for extracting known actions in
  45 // tools/metrics/actions/extract_actions.py.
  46 BASE_EXPORT void RecordComputedAction(const std::string& action);
  47
  48 // Called with the action string.
  49 typedef base::Callback<void(const std::string&)> ActionCallback;
  50
  51 // Add/remove action callbacks (see above).
  52 BASE_EXPORT void AddActionCallback(const ActionCallback& callback);
  53 BASE_EXPORT void RemoveActionCallback(const ActionCallback& callback);
  54
  55 }  // namespace base
  56
  57 #endif  // BASE_METRICS_USER_METRICS_H_