components/language_usage_metrics/language_usage_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 COMPONENTS_LANGUAGE_USAGE_METRICS_LANGUAGE_USAGE_METRICS_H_
   6 #define COMPONENTS_LANGUAGE_USAGE_METRICS_LANGUAGE_USAGE_METRICS_H_
   7
   8 #include <set>
   9 #include <string>
  10
  11 #include "base/basictypes.h"
  12 #include "base/gtest_prod_util.h"
  13
  14 namespace language_usage_metrics {
  15
  16 // Methods to record language usage as UMA histograms.
  17 class LanguageUsageMetrics {
  18  public:
  19   // Records accept languages as a UMA histogram. |accept_languages| is a
  20   // case-insensitive comma-separated list of languages/locales of either xx,
  21   // xx-YY, or xx_YY format where xx is iso-639 language code and YY is iso-3166
  22   // country code. Country code is ignored. That is, xx and XX-YY are considered
  23   // identical and recorded once.
  24   static void RecordAcceptLanguages(const std::string& accept_languages);
  25
  26   // Records the application language as a UMA histogram. |application_locale|
  27   // is a case-insensitive locale string of either xx, xx-YY, or xx_YY format.
  28   // Only the language part (xx in the example) is considered.
  29   static void RecordApplicationLanguage(const std::string& application_locale);
  30
  31   // Parses |locale| and returns the language code. Returns 0 in case of errors.
  32   // The language code is calculated from two alphabets. For example, if
  33   // |locale| is 'en' which represents 'English', the codes of 'e' and 'n' are
  34   // 101 and 110 respectively, and the language code will be 101 * 256 + 100 =
  35   // 25966.
  36   // |locale| should consist of only lower-case letters. This function doesn't
  37   // check whether |locale| is valid locale or not strictly.
  38   static int ToLanguageCode(const std::string &locale);
  39
  40  private:
  41   DISALLOW_IMPLICIT_CONSTRUCTORS(LanguageUsageMetrics);
  42
  43   // Parses |accept_languages| and returns a set of language codes in
  44   // |languages|.
  45   static void ParseAcceptLanguages(const std::string& accept_languages,
  46                                    std::set<int>* languages);
  47
  48   FRIEND_TEST_ALL_PREFIXES(LanguageUsageMetricsTest, ParseAcceptLanguages);
  49 };
  50
  51 }  // namespace language_usage_metrics
  52
  53 #endif  // COMPONENTS_LANGUAGE_USAGE_METRICS_LANGUAGE_USAGE_METRICS_H_