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 // This method *must* be called from the main thread.
  21 //
  22 // "Action" here means a user-generated event:
  23 //   good: "Reload", "CloseTab", and "IMEInvoked"
  24 //   not good: "SSLDialogShown", "PageLoaded", "DiskFull"
  25 // We use this to gather anonymized information about how users are
  26 // interacting with the browser.
  27 // WARNING: In calls to this function, UserMetricsAction and a
  28 // string literal parameter must be on the same line, e.g.
  29 //   RecordAction(UserMetricsAction("my extremely long action name"));
  30 // This ensures that our processing scripts can associate this action's hash
  31 // with its metric name. Therefore, it will be possible to retrieve the metric
  32 // name from the hash later on.
  33 //
  34 // Once a new recorded action is added, run
  35 //   tools/metrics/actions/extract_actions.py
  36 // to add the metric to actions.xml, then update the <owner>s and <description>
  37 // sections. Make sure to include the actions.xml file when you upload your code
  38 // for review!
  39 //
  40 // For more complicated situations (like when there are many different
  41 // possible actions), see RecordComputedAction.
  42 BASE_EXPORT void RecordAction(const UserMetricsAction& action);
  43
  44 // This function has identical input and behavior to RecordAction, but is
  45 // not automatically found by the action-processing scripts.  It can be used
  46 // when it's a pain to enumerate all possible actions, but if you use this
  47 // you need to also update the rules for extracting known actions in
  48 // tools/metrics/actions/extract_actions.py.
  49 BASE_EXPORT void RecordComputedAction(const std::string& action);
  50
  51 // Called with the action string.
  52 typedef base::Callback<void(const std::string&)> ActionCallback;
  53
  54 // Add/remove action callbacks (see above).
  55 BASE_EXPORT void AddActionCallback(const ActionCallback& callback);
  56 BASE_EXPORT void RemoveActionCallback(const ActionCallback& callback);
  57
  58 }  // namespace base
  59
  60 #endif  // BASE_METRICS_USER_METRICS_H_