1 /**
2  * Copyright (c) 2020, 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 "Experiments.h"
18 
19 #include <android-base/format.h>
20 #include <netdutils/DumpWriter.h>
21 #include <string>
22 
23 #include "util.h"
24 
25 namespace android::net {
26 
27 using netdutils::DumpWriter;
28 using netdutils::ScopedIndent;
29 
30 Experiments* Experiments::getInstance() {
31     // Instantiated on first use.
32     static Experiments instance{getExperimentFlagInt};
33     return &instance;
34 }
35 
36 Experiments::Experiments(GetExperimentFlagIntFunction getExperimentFlagIntFunction)
37     : mGetExperimentFlagIntFunction(std::move(getExperimentFlagIntFunction)) {
38     updateInternal();
39 }
40 
41 void Experiments::update() {
42     updateInternal();
43 }
44 
45 void Experiments::dump(DumpWriter& dw) const {
46     std::lock_guard guard(mMutex);
47     dw.println("Experiments list: ");
48     for (const auto& [key, value] : mFlagsMapInt) {
49         ScopedIndent indentStats(dw);
50         if (value == Experiments::kFlagIntDefault) {
51             dw.println(fmt::format("{}: UNSET", key));
52         } else {
53             dw.println(fmt::format("{}: {}", key, value));
54         }
55     }
56 }
57 
58 void Experiments::updateInternal() {
59     std::lock_guard guard(mMutex);
60     for (const auto& key : kExperimentFlagKeyList) {
61         mFlagsMapInt[key] = mGetExperimentFlagIntFunction(key, Experiments::kFlagIntDefault);
62     }
63 }
64 
65 int Experiments::getFlag(std::string_view key, int defaultValue) const {
66     std::lock_guard guard(mMutex);
67     auto it = mFlagsMapInt.find(key);
68     if (it != mFlagsMapInt.end() && it->second != Experiments::kFlagIntDefault) {
69         return it->second;
70     }
71     return defaultValue;
72 }
73 
74 }  // namespace android::net
75