2 * Copyright 2017-present Facebook, Inc.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
18 #include <folly/Conv.h>
19 #include <folly/Format.h>
20 #include <folly/experimental/logging/LogCategory.h>
21 #include <folly/experimental/logging/LogLevel.h>
22 #include <folly/experimental/logging/LogStream.h>
23 #include <folly/experimental/logging/LogStreamProcessor.h>
26 * Helper macro for implementing FB_LOG() and FB_LOGF().
28 * This macro generally should not be used directly by end users.
30 #define FB_LOG_IMPL(logger, level, type, ...) \
31 (!(logger).getCategory()->logCheck(level)) \
32 ? ::folly::logDisabledHelper( \
33 std::integral_constant<bool, ::folly::isLogLevelFatal(level)>{}) \
34 : ::folly::LogStreamVoidify<::folly::isLogLevelFatal(level)>{} & \
35 ::folly::LogStreamProcessor{(logger).getCategory(), \
44 * Log a message to the specified logger.
46 * This macro avoids evaluating the log arguments unless the log level check
49 * Beware that the logger argument is evaluated twice, so this argument should
50 * be an expression with no side-effects.
52 #define FB_LOG(logger, level, ...) \
55 ::folly::LogLevel::level, \
56 ::folly::LogStreamProcessor::APPEND, \
60 * Log a message to the specified logger, using a folly::format() string.
62 * The arguments will be processed using folly::format(). The format syntax
63 * is similar to Python format strings.
65 * This macro avoids evaluating the log arguments unless the log level check
68 * Beware that the logger argument is evaluated twice, so this argument should
69 * be an expression with no side-effects.
71 #define FB_LOGF(logger, level, fmt, arg1, ...) \
74 ::folly::LogLevel::level, \
75 ::folly::LogStreamProcessor::FORMAT, \
86 * Logger is the class you will use to specify the log category when logging
87 * messages with FB_LOG().
89 * Logger is really just a small wrapper class that contains a pointer to the
90 * appropriate LogCategory object. It primarily exists as syntactic sugar to
91 * allow for easily looking up LogCategory objects.
96 * Construct a Logger for the given category name.
98 * A LogCategory object for this category will be created if one does not
101 explicit Logger(folly::StringPiece name);
104 * Construct a Logger pointing to an existing LogCategory object.
106 explicit Logger(LogCategory* cat);
109 * Construct a Logger for a specific LoggerDB object, rather than the main
112 * This is primarily intended for use in unit tests.
114 Logger(LoggerDB* db, folly::StringPiece name);
117 * Get the LogCategory that this Logger refers to.
119 LogCategory* getCategory() const {
124 LogCategory* const category_{nullptr};