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- /*
- * Copyright 2012-present Facebook, Inc.
- *
- * 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 <atomic>
- #include <chrono>
- #include <glog/logging.h>
- #ifndef FB_LOG_EVERY_MS
- /**
- * Issues a LOG(severity) no more often than every
- * milliseconds. Example:
- *
- * FB_LOG_EVERY_MS(INFO, 10000) << "At least ten seconds passed"
- * " since you last saw this.";
- *
- * The implementation uses for statements to introduce variables in
- * a nice way that doesn't mess surrounding statements. It is thread
- * safe. Non-positive intervals will always log.
- */
- #define FB_LOG_EVERY_MS(severity, milli_interval) \
- for (decltype(milli_interval) FB_LEM_once = 1, \
- FB_LEM_interval = (milli_interval); \
- FB_LEM_once;) \
- for (::std::chrono::milliseconds::rep FB_LEM_prev, \
- FB_LEM_now = FB_LEM_interval <= 0 \
- ? 0 \
- : ::std::chrono::duration_cast<::std::chrono::milliseconds>( \
- ::std::chrono::system_clock::now().time_since_epoch()) \
- .count(); \
- FB_LEM_once;) \
- for (static ::std::atomic<::std::chrono::milliseconds::rep> FB_LEM_hist; \
- FB_LEM_once; \
- FB_LEM_once = 0) \
- if (FB_LEM_interval > 0 && \
- (FB_LEM_now - \
- (FB_LEM_prev = \
- FB_LEM_hist.load(std::memory_order_acquire)) < \
- FB_LEM_interval || \
- !FB_LEM_hist.compare_exchange_strong(FB_LEM_prev, FB_LEM_now))) { \
- } else \
- LOG(severity)
- #endif
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