Add Experiments to handle experiment flags logic
update experiment flags everytime when a resolver network is created or
destroyed.
Bug: 135717624
Bug: 151698212
Test: atest
Merged-In: I5375e78831c5994af74b9ecaca991f18db03eca6
Change-Id: I6288c1d47085cdb70ab5e6e19f183c289af56815
(cherry picked from commit fe85ad8052e0faaac88b0a14a9e78b2463507dd7)
diff --git a/Experiments.h b/Experiments.h
new file mode 100644
index 0000000..d8af673
--- /dev/null
+++ b/Experiments.h
@@ -0,0 +1,57 @@
+/**
+ * Copyright (c) 2020, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <mutex>
+#include <string>
+#include <string_view>
+#include <unordered_map>
+
+#include <android-base/thread_annotations.h>
+#include <netdutils/DumpWriter.h>
+
+namespace android::net {
+
+// TODO: Add some way to update the stored experiment flags periodically.
+// TODO: Refactor this class and make things easier. (e.g. remove string map.)
+class Experiments {
+ public:
+ using GetExperimentFlagIntFunction = std::function<int(const std::string&, int)>;
+ static Experiments* getInstance();
+ int getFlag(std::string_view key, int defaultValue) const EXCLUDES(mMutex);
+ void update();
+ void dump(netdutils::DumpWriter& dw) const EXCLUDES(mMutex);
+
+ Experiments(Experiments const&) = delete;
+ void operator=(Experiments const&) = delete;
+
+ private:
+ explicit Experiments(GetExperimentFlagIntFunction getExperimentFlagIntFunction);
+ Experiments() = delete;
+ void updateInternal() EXCLUDES(mMutex);
+ mutable std::mutex mMutex;
+ std::unordered_map<std::string_view, int> mFlagsMapInt GUARDED_BY(mMutex);
+ // TODO: Migrate other experiment flags to here.
+ // (retry_count, retransmission_time_interval, dot_connect_timeout_ms)
+ static constexpr const char* const kExperimentFlagKeyList[] = {
+ "keep_listening_udp", "parallel_lookup", "parallel_lookup_sleep_time"};
+ // For testing.
+ friend class ExperimentsTest;
+ const GetExperimentFlagIntFunction mGetExperimentFlagIntFunction;
+};
+
+} // namespace android::net