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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 
num_events()73   int num_events() { return num_events_; }
74 
set_hardware_class(const std::string & hardware_class)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:
locked()81   bool locked() const { return locked_; }
82 
uma_proto()83   metrics::ChromeUserMetricsExtension* uma_proto() { return &uma_proto_; }
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