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- /*
- * Copyright 2015-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 <chrono>
- #include <string>
- #include <type_traits>
- #include <folly/Conv.h>
- #include <folly/Format.h>
- #include <folly/Optional.h>
- #include <folly/String.h>
- #include <glog/logging.h>
- namespace folly {
- // Default logger
- enum class GoogleLoggerStyle { SECONDS, PRETTY };
- template <GoogleLoggerStyle>
- struct GoogleLogger;
- /**
- * Automatically times a block of code, printing a specified log message on
- * destruction or whenever the log() method is called. For example:
- *
- * AutoTimer t("Foo() completed");
- * doWork();
- * t.log("Do work finished");
- * doMoreWork();
- *
- * This would print something like:
- * "Do work finished in 1.2 seconds"
- * "Foo() completed in 4.3 seconds"
- *
- * You can customize what you use as the logger and clock. The logger needs
- * to have an operator()(StringPiece, std::chrono::duration<double>) that
- * gets a message and a duration. The clock needs to model Clock from
- * std::chrono.
- *
- * The default logger logs usings glog. It only logs if the message is
- * non-empty, so you can also just use this class for timing, e.g.:
- *
- * AutoTimer t;
- * doWork()
- * const auto how_long = t.log();
- */
- template <
- class Logger = GoogleLogger<GoogleLoggerStyle::PRETTY>,
- class Clock = std::chrono::high_resolution_clock>
- class AutoTimer final {
- public:
- using DoubleSeconds = std::chrono::duration<double>;
- explicit AutoTimer(
- std::string&& msg = "",
- const DoubleSeconds& minTimetoLog = DoubleSeconds::zero(),
- Logger&& logger = Logger())
- : destructionMessage_(std::move(msg)),
- minTimeToLog_(minTimetoLog),
- logger_(std::move(logger)) {}
- // It doesn't really make sense to copy AutoTimer
- // Movable to make sure the helper method for creating an AutoTimer works.
- AutoTimer(const AutoTimer&) = delete;
- AutoTimer(AutoTimer&&) = default;
- AutoTimer& operator=(const AutoTimer&) = delete;
- AutoTimer& operator=(AutoTimer&&) = default;
- ~AutoTimer() {
- if (destructionMessage_) {
- log(destructionMessage_.value());
- }
- }
- DoubleSeconds log(StringPiece msg = "") {
- return logImpl(Clock::now(), msg);
- }
- template <typename... Args>
- DoubleSeconds log(Args&&... args) {
- auto now = Clock::now();
- return logImpl(now, to<std::string>(std::forward<Args>(args)...));
- }
- template <typename... Args>
- DoubleSeconds logFormat(Args&&... args) {
- auto now = Clock::now();
- return logImpl(now, format(std::forward<Args>(args)...).str());
- }
- private:
- // We take in the current time so that we don't measure time to call
- // to<std::string> or format() in the duration.
- DoubleSeconds logImpl(std::chrono::time_point<Clock> now, StringPiece msg) {
- auto duration = now - start_;
- if (duration >= minTimeToLog_) {
- logger_(msg, duration);
- }
- start_ = Clock::now(); // Don't measure logging time
- return duration;
- }
- Optional<std::string> destructionMessage_;
- std::chrono::time_point<Clock> start_ = Clock::now();
- DoubleSeconds minTimeToLog_;
- Logger logger_;
- };
- template <
- class Logger = GoogleLogger<GoogleLoggerStyle::PRETTY>,
- class Clock = std::chrono::high_resolution_clock>
- auto makeAutoTimer(
- std::string&& msg = "",
- const std::chrono::duration<double>& minTimeToLog =
- std::chrono::duration<double>::zero(),
- Logger&& logger = Logger()) {
- return AutoTimer<Logger, Clock>(
- std::move(msg), minTimeToLog, std::move(logger));
- }
- template <GoogleLoggerStyle Style>
- struct GoogleLogger final {
- void operator()(StringPiece msg, const std::chrono::duration<double>& sec)
- const {
- if (msg.empty()) {
- return;
- }
- if (Style == GoogleLoggerStyle::PRETTY) {
- LOG(INFO) << msg << " in "
- << prettyPrint(sec.count(), PrettyType::PRETTY_TIME);
- } else {
- LOG(INFO) << msg << " in " << sec.count() << " seconds";
- }
- }
- };
- } // namespace folly
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