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/*
* Copyright (C) 2017 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.
*/
#ifndef NETUTILS_MISC_H
#define NETUTILS_MISC_H
#include <map>
namespace android {
namespace netdutils {
// Lookup key in map, returing a default value if key is not found
template <typename U, typename V>
inline const V& findWithDefault(const std::map<U, V>& map, const U& key, const V& dflt) {
auto it = map.find(key);
return (it == map.end()) ? dflt : it->second;
}
// Movable, copiable, scoped lambda (or std::function) runner. Useful
// for running arbitrary cleanup or logging code when exiting a scope.
//
// Compare to defer in golang.
template <typename FnT>
class Cleanup {
public:
Cleanup() = delete;
explicit Cleanup(FnT fn) : mFn(fn) {}
~Cleanup() { if (!mReleased) mFn(); }
void release() { mReleased = true; }
private:
bool mReleased{false};
FnT mFn;
};
// Helper to make a new Cleanup. Avoids complex or impossible syntax
// when wrapping lambdas.
//
// Usage:
// auto cleanup = makeCleanup([](){ your_code_here; });
template <typename FnT>
Cleanup<FnT> makeCleanup(FnT fn) {
return Cleanup<FnT>(fn);
}
} // namespace netdutils
} // namespace android
#endif /* NETUTILS_MISC_H */
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