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