1 /*
2  * Copyright (C) 2021 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #include "FlagProvider.h"
18 
19 using server_configurable_flags::GetServerConfigurableFlag;
20 using std::string;
21 using std::vector;
22 
23 namespace android {
24 namespace os {
25 namespace statsd {
26 
FlagProvider()27 FlagProvider::FlagProvider()
28     : mIsAtLeastSFunc(isAtLeastS), mGetServerFlagFunc(GetServerConfigurableFlag) {
29 }
30 
getInstance()31 FlagProvider& FlagProvider::getInstance() {
32     static FlagProvider instance;
33     return instance;
34 }
35 
getFlagString(const string & flagName,const string & defaultValue) const36 string FlagProvider::getFlagString(const string& flagName, const string& defaultValue) const {
37     return getFlagStringInternal(flagName, defaultValue, /* isBootFlag= */ false);
38 }
39 
getFlagBool(const string & flagName,const string & defaultValue) const40 bool FlagProvider::getFlagBool(const string& flagName, const string& defaultValue) const {
41     return getFlagStringInternal(flagName, defaultValue, /* isBootFlag= */ false) == FLAG_TRUE;
42 }
43 
getBootFlagString(const string & flagName,const string & defaultValue) const44 string FlagProvider::getBootFlagString(const string& flagName, const string& defaultValue) const {
45     return getFlagStringInternal(flagName, defaultValue, /* isBootFlag= */ true);
46 }
47 
getBootFlagBool(const string & flagName,const string & defaultValue) const48 bool FlagProvider::getBootFlagBool(const string& flagName, const string& defaultValue) const {
49     return getFlagStringInternal(flagName, defaultValue, /* isBootFlag= */ true) == FLAG_TRUE;
50 }
51 
initBootFlags(const vector<string> & flags)52 void FlagProvider::initBootFlags(const vector<string>& flags) {
53     std::lock_guard<std::mutex> lock(mFlagsMutex);
54     mBootFlags.clear();
55     for (const string& flagName : flags) {
56         string flagVal = mGetServerFlagFunc(STATSD_NATIVE_BOOT_NAMESPACE, flagName, FLAG_EMPTY);
57         if (flagVal != FLAG_EMPTY) {
58             mBootFlags[flagName] = flagVal;
59         }
60     }
61 }
62 
overrideFlag(const string & flagName,const std::string & flagValue,const bool isBootFlag)63 void FlagProvider::overrideFlag(const string& flagName, const std::string& flagValue,
64                                 const bool isBootFlag) {
65     std::lock_guard<std::mutex> lock(mFlagsMutex);
66     mLocalFlags[getLocalFlagKey(flagName, isBootFlag)] = flagValue;
67 }
68 
overrideFuncs(const IsAtLeastSFunc & isAtLeastSFunc,const GetServerFlagFunc & getServerFlagFunc)69 void FlagProvider::overrideFuncs(const IsAtLeastSFunc& isAtLeastSFunc,
70                                  const GetServerFlagFunc& getServerFlagFunc) {
71     std::lock_guard<std::mutex> lock(mFlagsMutex);
72     overrideFuncsLocked(isAtLeastSFunc, getServerFlagFunc);
73 }
74 
overrideFuncsLocked(const IsAtLeastSFunc & isAtLeastSFunc,const GetServerFlagFunc & getServerFlagFunc)75 void FlagProvider::overrideFuncsLocked(const IsAtLeastSFunc& isAtLeastSFunc,
76                                        const GetServerFlagFunc& getServerFlagFunc) {
77     mIsAtLeastSFunc = isAtLeastSFunc;
78     mGetServerFlagFunc = getServerFlagFunc;
79 }
80 
getLocalFlagKey(const string & flagName,const bool isBootFlag) const81 string FlagProvider::getLocalFlagKey(const string& flagName, const bool isBootFlag) const {
82     return isBootFlag ? STATSD_NATIVE_BOOT_NAMESPACE + "." + flagName
83                       : STATSD_NATIVE_NAMESPACE + "." + flagName;
84 }
85 
getFlagStringInternal(const std::string & flagName,const std::string & defaultValue,const bool isBootFlag) const86 string FlagProvider::getFlagStringInternal(const std::string& flagName,
87                                            const std::string& defaultValue,
88                                            const bool isBootFlag) const {
89     std::lock_guard<std::mutex> lock(mFlagsMutex);
90     if (!mIsAtLeastSFunc()) {
91         return defaultValue;
92     }
93     string localFlagKey = getLocalFlagKey(flagName, isBootFlag);
94     if (mLocalFlags.find(localFlagKey) != mLocalFlags.end()) {
95         return mLocalFlags.at(localFlagKey);
96     }
97     if (!isBootFlag) {
98         return mGetServerFlagFunc(STATSD_NATIVE_NAMESPACE, flagName, defaultValue);
99     }
100     const auto& it = mBootFlags.find(flagName);
101     return it == mBootFlags.end() ? defaultValue : it->second;
102 }
103 
104 }  // namespace statsd
105 }  // namespace os
106 }  // namespace android
107