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      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_RAPPOR_RAPPOR_SERVICE_H_
      6 #define COMPONENTS_RAPPOR_RAPPOR_SERVICE_H_
      7 
      8 #include <map>
      9 #include <string>
     10 
     11 #include "base/basictypes.h"
     12 #include "base/macros.h"
     13 #include "base/memory/scoped_ptr.h"
     14 #include "base/timer/timer.h"
     15 #include "components/metrics/daily_event.h"
     16 
     17 class PrefRegistrySimple;
     18 class PrefService;
     19 
     20 namespace net {
     21 class URLRequestContextGetter;
     22 }
     23 
     24 namespace rappor {
     25 
     26 class LogUploader;
     27 class RapporMetric;
     28 class RapporReports;
     29 struct RapporParameters;
     30 
     31 // The type of data stored in a metric.
     32 enum RapporType {
     33   // For sampling the eTLD+1 of a URL.
     34   ETLD_PLUS_ONE_RAPPOR_TYPE = 0,
     35   NUM_RAPPOR_TYPES
     36 };
     37 
     38 // This class provides an interface for recording samples for rappor metrics,
     39 // and periodically generates and uploads reports based on the collected data.
     40 class RapporService {
     41  public:
     42   // Constructs a RapporService.
     43   // Calling code is responsible for ensuring that the lifetime of
     44   // |pref_service| is longer than the lifetime of RapporService.
     45   explicit RapporService(PrefService* pref_service);
     46   virtual ~RapporService();
     47 
     48   // Add an observer for collecting daily metrics.
     49   void AddDailyObserver(scoped_ptr<metrics::DailyEvent::Observer> observer);
     50 
     51   // Starts the periodic generation of reports and upload attempts.
     52   void Start(net::URLRequestContextGetter* context,
     53              bool metrics_enabled);
     54 
     55   // Records a sample of the rappor metric specified by |metric_name|.
     56   // Creates and initializes the metric, if it doesn't yet exist.
     57   void RecordSample(const std::string& metric_name,
     58                     RapporType type,
     59                     const std::string& sample);
     60 
     61   // Sets the cohort value. For use by tests only.
     62   void SetCohortForTesting(uint32_t cohort) { cohort_ = cohort; }
     63 
     64   // Sets the secret value. For use by tests only.
     65   void SetSecretForTesting(const std::string& secret) { secret_ = secret; }
     66 
     67   // Registers the names of all of the preferences used by RapporService in the
     68   // provided PrefRegistry. This should be called before calling Start().
     69   static void RegisterPrefs(PrefRegistrySimple* registry);
     70 
     71  protected:
     72   // Retrieves the cohort number this client was assigned to, generating it if
     73   // doesn't already exist. The cohort should be persistent.
     74   void LoadCohort();
     75 
     76   // Retrieves the value for secret_ from preferences, generating it if doesn't
     77   // already exist. The secret should be persistent, so that additional bits
     78   // from the client do not get exposed over time.
     79   void LoadSecret();
     80 
     81   // Logs all of the collected metrics to the reports proto message and clears
     82   // the internal map. Exposed for tests. Returns true if any metrics were
     83   // recorded.
     84   bool ExportMetrics(RapporReports* reports);
     85 
     86   // Records a sample of the rappor metric specified by |parameters|.
     87   // Creates and initializes the metric, if it doesn't yet exist.
     88   // Exposed for tests.
     89   void RecordSampleInternal(const std::string& metric_name,
     90                             const RapporParameters& parameters,
     91                             const std::string& sample);
     92 
     93  private:
     94   // Check if the service has been started successfully.
     95   bool IsInitialized() const;
     96 
     97   // Called whenever the logging interval elapses to generate a new log of
     98   // reports and pass it to the uploader.
     99   void OnLogInterval();
    100 
    101   // Finds a metric in the metrics_map_, creating it if it doesn't already
    102   // exist.
    103   RapporMetric* LookUpMetric(const std::string& metric_name,
    104                              const RapporParameters& parameters);
    105 
    106   // A weak pointer to the PrefService used to read and write preferences.
    107   PrefService* pref_service_;
    108 
    109   // Client-side secret used to generate fake bits.
    110   std::string secret_;
    111 
    112   // The cohort this client is assigned to. -1 is uninitialized.
    113   int32_t cohort_;
    114 
    115   // Timer which schedules calls to OnLogInterval().
    116   base::OneShotTimer<RapporService> log_rotation_timer_;
    117 
    118   // A daily event for collecting metrics once a day.
    119   metrics::DailyEvent daily_event_;
    120 
    121   // A private LogUploader instance for sending reports to the server.
    122   scoped_ptr<LogUploader> uploader_;
    123 
    124   // We keep all registered metrics in a map, from name to metric.
    125   // The map owns the metrics it contains.
    126   std::map<std::string, RapporMetric*> metrics_map_;
    127 
    128   DISALLOW_COPY_AND_ASSIGN(RapporService);
    129 };
    130 
    131 }  // namespace rappor
    132 
    133 #endif  // COMPONENTS_RAPPOR_RAPPOR_SERVICE_H_
    134