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
19class GURL;
20
21namespace base {
22class HistogramSamples;
23}  // namespace base
24
25// This class provides base functionality for logging metrics data.
26class 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_
104