chrome/common/metrics/metrics_log_base.h

   1 // Copyright (c) 2012 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 // This file defines a set of user experience metrics data recorded by
   6 // the MetricsService.  This is the unit of data that is sent to the server.
   7
   8 #ifndef CHROME_COMMON_METRICS_METRICS_LOG_BASE_H_
   9 #define CHROME_COMMON_METRICS_METRICS_LOG_BASE_H_
  10
  11 #include <string>
  12
  13 #include "base/basictypes.h"
  14 #include "base/metrics/histogram.h"
  15 #include "base/time/time.h"
  16 #include "chrome/common/metrics/proto/chrome_user_metrics_extension.pb.h"
  17 #include "content/public/common/page_transition_types.h"
  18
  19 class GURL;
  20
  21 namespace base {
  22 class HistogramSamples;
  23 }  // namespace base
  24
  25 // This class provides base functionality for logging metrics data.
  26 class MetricsLogBase {
  27  public:
  28   // TODO(asvitkine): Make this a field on the log and remove the NO_LOG value.
  29   enum LogType {
  30     INITIAL_LOG,  // The first log of a session.
  31     ONGOING_LOG,  // Subsequent logs in a session.
  32     NO_LOG,       // Placeholder value for when there is no log.
  33   };
  34
  35   // Creates a new metrics log
  36   // client_id is the identifier for this profile on this installation
  37   // session_id is an integer that's incremented on each application launch
  38   MetricsLogBase(const std::string& client_id,
  39                  int session_id,
  40                  const std::string& version_string);
  41   virtual ~MetricsLogBase();
  42
  43   // Computes the MD5 hash of the given string, and returns the first 8 bytes of
  44   // the hash.
  45   static uint64 Hash(const std::string& value);
  46
  47   // Get the GMT buildtime for the current binary, expressed in seconds since
  48   // Januray 1, 1970 GMT.
  49   // The value is used to identify when a new build is run, so that previous
  50   // reliability stats, from other builds, can be abandoned.
  51   static int64 GetBuildTime();
  52
  53   // Convenience function to return the current time at a resolution in seconds.
  54   // This wraps base::TimeTicks, and hence provides an abstract time that is
  55   // always incrementing for use in measuring time durations.
  56   static int64 GetCurrentTime();
  57
  58   // Records a user-initiated action.
  59   void RecordUserAction(const char* key);
  60
  61   // Record any changes in a given histogram for transmission.
  62   void RecordHistogramDelta(const std::string& histogram_name,
  63                             const base::HistogramSamples& snapshot);
  64
  65   // Stop writing to this record and generate the encoded representation.
  66   // None of the Record* methods can be called after this is called.
  67   void CloseLog();
  68
  69   // Fills |encoded_log| with the serialized protobuf representation of the
  70   // record.  Must only be called after CloseLog() has been called.
  71   void GetEncodedLog(std::string* encoded_log);
  72
  73   int num_events() { return num_events_; }
  74
  75   void set_hardware_class(const std::string& hardware_class) {
  76     uma_proto_.mutable_system_profile()->mutable_hardware()->set_hardware_class(
  77         hardware_class);
  78   }
  79
  80  protected:
  81   bool locked() const { return locked_; }
  82
  83   metrics::ChromeUserMetricsExtension* uma_proto() { return &uma_proto_; }
  84   const metrics::ChromeUserMetricsExtension* uma_proto() const {
  85     return &uma_proto_;
  86   }
  87
  88   // TODO(isherman): Remove this once the XML pipeline is outta here.
  89   int num_events_;  // the number of events recorded in this log
  90
  91  private:
  92   // locked_ is true when record has been packed up for sending, and should
  93   // no longer be written to.  It is only used for sanity checking and is
  94   // not a real lock.
  95   bool locked_;
  96
  97   // Stores the protocol buffer representation for this log.
  98   metrics::ChromeUserMetricsExtension uma_proto_;
  99
 100   DISALLOW_COPY_AND_ASSIGN(MetricsLogBase);
 101 };
 102
 103 #endif  // CHROME_COMMON_METRICS_METRICS_LOG_BASE_H_