73 lines
2.6 KiB
C++
73 lines
2.6 KiB
C++
/**
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* Copyright (c) 2020, The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#pragma once
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#include <climits>
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#include <mutex>
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#include <string>
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#include <string_view>
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#include <unordered_map>
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#include <android-base/thread_annotations.h>
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#include <netdutils/DumpWriter.h>
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namespace android::net {
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// TODO: Add some way to update the stored experiment flags periodically.
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// TODO: Refactor this class and make things easier. (e.g. remove string map.)
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class Experiments {
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public:
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using GetExperimentFlagIntFunction = std::function<int(const std::string&, int)>;
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static Experiments* getInstance();
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int getFlag(std::string_view key, int defaultValue) const EXCLUDES(mMutex);
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void update();
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void dump(netdutils::DumpWriter& dw) const EXCLUDES(mMutex);
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Experiments(Experiments const&) = delete;
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void operator=(Experiments const&) = delete;
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private:
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explicit Experiments(GetExperimentFlagIntFunction getExperimentFlagIntFunction);
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Experiments() = delete;
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void updateInternal() EXCLUDES(mMutex);
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mutable std::mutex mMutex;
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std::unordered_map<std::string_view, int> mFlagsMapInt GUARDED_BY(mMutex);
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// TODO: Migrate other experiment flags to here.
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// (retry_count, retransmission_time_interval)
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static constexpr const char* const kExperimentFlagKeyList[] = {
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"keep_listening_udp",
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"parallel_lookup_release",
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"parallel_lookup_sleep_time",
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"sort_nameservers",
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"dot_async_handshake",
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"dot_connect_timeout_ms",
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"dot_maxtries",
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"dot_revalidation_threshold",
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"dot_xport_unusable_threshold",
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"dot_query_timeout_ms",
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"dot_validation_latency_factor",
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"dot_validation_latency_offset_ms",
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};
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// This value is used in updateInternal as the default value if any flags can't be found.
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static constexpr int kFlagIntDefault = INT_MIN;
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// For testing.
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friend class ExperimentsTest;
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const GetExperimentFlagIntFunction mGetExperimentFlagIntFunction;
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};
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} // namespace android::net
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