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1 // Copyright 2017 The Chromium Authors. All rights reserved. | 1 // Copyright 2017 The Chromium Authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #ifndef CHROME_INSTALLER_UTIL_EXPERIMENT_STORAGE_H_ | 5 #ifndef CHROME_INSTALLER_UTIL_EXPERIMENT_STORAGE_H_ |
6 #define CHROME_INSTALLER_UTIL_EXPERIMENT_STORAGE_H_ | 6 #define CHROME_INSTALLER_UTIL_EXPERIMENT_STORAGE_H_ |
7 | 7 |
8 #include <memory> | 8 #include <memory> |
9 | 9 |
10 #include "base/macros.h" | 10 #include "base/macros.h" |
11 #include "base/strings/string16.h" | 11 #include "base/strings/string16.h" |
12 #include "base/win/scoped_handle.h" | 12 #include "base/win/scoped_handle.h" |
13 | 13 |
14 namespace installer { | 14 namespace installer { |
15 | 15 |
16 class Experiment; | 16 class Experiment; |
17 struct ExperimentMetrics; | 17 struct ExperimentMetrics; |
18 | 18 |
19 // Manages the storage of experiment state on the machine. | 19 // Manages the storage of experiment state on the machine. |
20 // | 20 // |
21 // Participation is a per-install property evaluated one time to determine | 21 // Participation is a per-install property evaluated one time to determine which |
22 // whether or not the install as a whole participates in the study. It is | 22 // study the client participates in. It is stored in the install's ClientState |
23 // stored in the install's ClientState key. | 23 // key. |
24 // | 24 // |
25 // ExperimentMetrics are stored in a per-install experiment_label, while the | 25 // ExperimentMetrics are stored in a per-install experiment_label, while the |
26 // fine-grained Experiment data are stored in a per-user key in Chrome's | 26 // fine-grained Experiment data are stored in a per-user key in Chrome's |
27 // ClientState or ClientStateMedium key. For system-level installs, metrics are | 27 // ClientState or ClientStateMedium key. For system-level installs, metrics are |
28 // reported for only a single user on the machine, so only that one user will | 28 // reported for only a single user on the machine, so only that one user will |
29 // participate in the experiment. | 29 // participate in the experiment. |
30 // | 30 // |
31 // Owing to this "metrics are per-install" property in the face of potentially | 31 // Owing to this "metrics are per-install" property in the face of potentially |
32 // multiple users running the same install, ExperimentMetrics are considered the | 32 // multiple users running the same install, ExperimentMetrics are considered the |
33 // source of truth for an install's participation in the experiment. For any | 33 // source of truth for an install's participation in the experiment. For any |
34 // given state expressed in the experiment_label holding these metrics, there | 34 // given state expressed in the experiment_label holding these metrics, there |
35 // should be matching Experiment data for precisely one user. | 35 // should be matching Experiment data for precisely one user. |
36 // | 36 // |
37 // As state is written across multiple locations in the registry, a global | 37 // As state is written across multiple locations in the registry, a global |
38 // mutex is used for all reads and writes to ensure consistent state. | 38 // mutex is used for all reads and writes to ensure consistent state. |
39 class ExperimentStorage { | 39 class ExperimentStorage { |
40 public: | 40 public: |
41 enum class Participation { | 41 // An identifier of which study the install participates in. |
42 // No participation state was found for the install. | 42 enum Study : uint32_t { |
43 kNotEvaluated, | 43 kNoStudySelected = 0, |
44 | 44 kStudyOne = 1, |
45 // The client is not participating in the study. | 45 kStudyTwo = 2, |
46 kNotParticipating, | |
47 | |
48 // The client is participating in the study. | |
49 kIsParticipating, | |
50 }; | 46 }; |
51 | 47 |
52 // Grants the holder exclusive access to the data in the registry. Consumers | 48 // Grants the holder exclusive access to the data in the registry. Consumers |
53 // are expected to not hold an instance across any blocking operations. | 49 // are expected to not hold an instance across any blocking operations. |
54 class Lock { | 50 class Lock { |
55 public: | 51 public: |
56 ~Lock(); | 52 ~Lock(); |
57 | 53 |
58 // Reads the participation state for the install. Returns false in case of | 54 // Reads the participation state for the install. Returns false in case of |
59 // error. | 55 // error. |participation| is set to kNotEvaluated if no value is present; |
60 bool ReadParticipation(Participation* participation); | 56 // otherwise, it is set to the value found. |
| 57 bool ReadParticipation(Study* participation); |
61 | 58 |
62 // Writes the participation state for the install. Returns false if the | 59 // Writes the participation state for the install. Returns false if the |
63 // write failed. | 60 // write failed. |
64 bool WriteParticipation(Participation participation); | 61 bool WriteParticipation(Study participation); |
65 | 62 |
66 // Loads the experiment metrics and data from the registry. Returns false if | 63 // Loads the experiment metrics and data from the registry. Returns false if |
67 // the state in the registry corresponds to a different user or could not be | 64 // the state in the registry corresponds to a different user or could not be |
68 // read. | 65 // read. |
69 bool LoadExperiment(Experiment* experiment); | 66 bool LoadExperiment(Experiment* experiment); |
70 | 67 |
71 // Stores the experiment metrics and data in |experiment| into the registry. | 68 // Stores the experiment metrics and data in |experiment| into the registry. |
72 bool StoreExperiment(const Experiment& experiment); | 69 bool StoreExperiment(const Experiment& experiment); |
73 | 70 |
74 // Loads per-install experiment metrics into |metrics|. Returns true if a | 71 // Loads per-install experiment metrics into |metrics|. Returns true if a |
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143 | 140 |
144 // A global mutex with a distinct name for the current installation. | 141 // A global mutex with a distinct name for the current installation. |
145 base::win::ScopedHandle mutex_; | 142 base::win::ScopedHandle mutex_; |
146 | 143 |
147 DISALLOW_COPY_AND_ASSIGN(ExperimentStorage); | 144 DISALLOW_COPY_AND_ASSIGN(ExperimentStorage); |
148 }; | 145 }; |
149 | 146 |
150 } // namespace installer | 147 } // namespace installer |
151 | 148 |
152 #endif // CHROME_INSTALLER_UTIL_EXPERIMENT_STORAGE_H_ | 149 #endif // CHROME_INSTALLER_UTIL_EXPERIMENT_STORAGE_H_ |
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