1 // Copyright 2014 The Chromium Authors
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include <jni.h>
6
7 #include <map>
8 #include <string>
9
10 #include "base/android/jni_string.h"
11 #include "base/base_jni/FieldTrialList_jni.h"
12 #include "base/lazy_instance.h"
13 #include "base/metrics/field_trial.h"
14 #include "base/metrics/field_trial_list_including_low_anonymity.h"
15 #include "base/metrics/field_trial_params.h"
16
17 using base::android::ConvertJavaStringToUTF8;
18 using base::android::ConvertUTF8ToJavaString;
19 using base::android::JavaParamRef;
20 using base::android::ScopedJavaLocalRef;
21
22 namespace {
23
24 // Log trials and their groups on activation, for debugging purposes.
25 class TrialLogger : public base::FieldTrialList::Observer {
26 public:
TrialLogger()27 TrialLogger() {}
28
29 TrialLogger(const TrialLogger&) = delete;
30 TrialLogger& operator=(const TrialLogger&) = delete;
31
OnFieldTrialGroupFinalized(const base::FieldTrial & trial,const std::string & group_name)32 void OnFieldTrialGroupFinalized(const base::FieldTrial& trial,
33 const std::string& group_name) override {
34 Log(trial.trial_name(), group_name);
35 }
36
Log(const std::string & trial_name,const std::string & group_name)37 static void Log(const std::string& trial_name,
38 const std::string& group_name) {
39 // Changes to format of the log message below must be accompanied by
40 // changes to finch smoke tests since they look for this log message
41 // in the logcat.
42 LOG(INFO) << "Active field trial \"" << trial_name
43 << "\" in group \"" << group_name<< '"';
44 }
45
46 protected:
~TrialLogger()47 ~TrialLogger() override {}
48 };
49
50 base::LazyInstance<TrialLogger>::Leaky g_trial_logger =
51 LAZY_INSTANCE_INITIALIZER;
52
53 } // namespace
54
JNI_FieldTrialList_FindFullName(JNIEnv * env,const JavaParamRef<jstring> & jtrial_name)55 static ScopedJavaLocalRef<jstring> JNI_FieldTrialList_FindFullName(
56 JNIEnv* env,
57 const JavaParamRef<jstring>& jtrial_name) {
58 std::string trial_name(ConvertJavaStringToUTF8(env, jtrial_name));
59 return ConvertUTF8ToJavaString(
60 env, base::FieldTrialList::FindFullName(trial_name));
61 }
62
JNI_FieldTrialList_TrialExists(JNIEnv * env,const JavaParamRef<jstring> & jtrial_name)63 static jboolean JNI_FieldTrialList_TrialExists(
64 JNIEnv* env,
65 const JavaParamRef<jstring>& jtrial_name) {
66 std::string trial_name(ConvertJavaStringToUTF8(env, jtrial_name));
67 return base::FieldTrialList::TrialExists(trial_name);
68 }
69
JNI_FieldTrialList_GetVariationParameter(JNIEnv * env,const JavaParamRef<jstring> & jtrial_name,const JavaParamRef<jstring> & jparameter_key)70 static ScopedJavaLocalRef<jstring> JNI_FieldTrialList_GetVariationParameter(
71 JNIEnv* env,
72 const JavaParamRef<jstring>& jtrial_name,
73 const JavaParamRef<jstring>& jparameter_key) {
74 std::map<std::string, std::string> parameters;
75 base::GetFieldTrialParams(ConvertJavaStringToUTF8(env, jtrial_name),
76 ¶meters);
77 return ConvertUTF8ToJavaString(
78 env, parameters[ConvertJavaStringToUTF8(env, jparameter_key)]);
79 }
80
81 // JNI_FieldTrialList_LogActiveTrials() is static function, this makes friending
82 // it a hassle because it must be declared in the file that the friend
83 // declaration is in, but its declaration can't be included in multiple places
84 // or things get messy and the linker gets mad. This helper class exists only to
85 // friend the JNI function and is, in turn, friended by
86 // FieldTrialListIncludingLowAnonymity which allows for the private
87 // GetActiveFieldTrialGroups() to be reached.
88 class AndroidFieldTrialListLogActiveTrialsFriendHelper {
89 private:
90 friend void ::JNI_FieldTrialList_LogActiveTrials(JNIEnv* env);
91
AddObserver(base::FieldTrialList::Observer * observer)92 static bool AddObserver(base::FieldTrialList::Observer* observer) {
93 return base::FieldTrialListIncludingLowAnonymity::AddObserver(observer);
94 }
95
GetActiveFieldTrialGroups(base::FieldTrial::ActiveGroups * active_groups)96 static void GetActiveFieldTrialGroups(
97 base::FieldTrial::ActiveGroups* active_groups) {
98 base::FieldTrialListIncludingLowAnonymity::GetActiveFieldTrialGroups(
99 active_groups);
100 }
101 };
102
JNI_FieldTrialList_LogActiveTrials(JNIEnv * env)103 static void JNI_FieldTrialList_LogActiveTrials(JNIEnv* env) {
104 DCHECK(!g_trial_logger.IsCreated()); // This need only be called once.
105
106 LOG(INFO) << "Logging active field trials...";
107 AndroidFieldTrialListLogActiveTrialsFriendHelper::AddObserver(
108 &g_trial_logger.Get());
109
110 // Log any trials that were already active before adding the observer.
111 std::vector<base::FieldTrial::ActiveGroup> active_groups;
112 AndroidFieldTrialListLogActiveTrialsFriendHelper::GetActiveFieldTrialGroups(
113 &active_groups);
114 for (const base::FieldTrial::ActiveGroup& group : active_groups) {
115 TrialLogger::Log(group.trial_name, group.group_name);
116 }
117 }
118
JNI_FieldTrialList_CreateFieldTrial(JNIEnv * env,const JavaParamRef<jstring> & jtrial_name,const JavaParamRef<jstring> & jgroup_name)119 static jboolean JNI_FieldTrialList_CreateFieldTrial(
120 JNIEnv* env,
121 const JavaParamRef<jstring>& jtrial_name,
122 const JavaParamRef<jstring>& jgroup_name) {
123 return base::FieldTrialList::CreateFieldTrial(
124 ConvertJavaStringToUTF8(env, jtrial_name),
125 ConvertJavaStringToUTF8(env, jgroup_name)) != nullptr;
126 }
127