folly/folly/GLog.h

/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * 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 <folly/Likely.h>

#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) …

#endif

/**
 * Issues a LOG(severity) once.
 *
 *   FB_LOG_ONCE(ERROR) << "Log this error only once";
 *
 * This macro is thread-safe and does not impact surrounding statements.
 *
 * NOTE: A load() is used in the fast-path scenario (steady state) in order to
 * avoid a locked RMW operation.
 */
#ifndef FB_LOG_ONCE
#define FB_LOG_ONCE(severity) …
#endif