2 * Copyright 2004-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.
21 #include <type_traits>
23 #include <folly/Portability.h>
24 #include <folly/Range.h>
31 * Higher levels are more important than lower ones.
33 * However, the numbers in the DBG* level names are reversed, and can be
34 * thought of as debug verbosity levels. Increasing DBG* numbers mean
35 * increasing level of verbosity. DBG0 is the least verbose debug level,
36 * DBG1 is one level higher of verbosity, etc.
38 enum class LogLevel : uint32_t {
59 // Unfortunately Windows headers #define ERROR, so we cannot use
60 // it as an enum value name. We only provide ERR instead.
65 // DFATAL log messages crash the program on debug builds.
67 // FATAL log messages always abort the program.
68 // This level is equivalent to MAX_LEVEL.
71 // The most significant bit is used by LogCategory to store a flag value,
72 // so the maximum value has that bit cleared.
74 // (We call this MAX_LEVEL instead of MAX just since MAX() is commonly
75 // defined as a preprocessor macro by some C headers.)
76 MAX_LEVEL = 0x7fffffff,
80 * Support adding and subtracting integers from LogLevels, to create slightly
81 * adjusted log level values.
83 inline constexpr LogLevel operator+(LogLevel level, uint32_t value) {
84 // Cap the result at LogLevel::MAX_LEVEL
85 return ((static_cast<uint32_t>(level) + value) >
86 static_cast<uint32_t>(LogLevel::MAX_LEVEL))
88 : static_cast<LogLevel>(static_cast<uint32_t>(level) + value);
90 inline LogLevel& operator+=(LogLevel& level, uint32_t value) {
91 level = level + value;
94 inline constexpr LogLevel operator-(LogLevel level, uint32_t value) {
95 return static_cast<LogLevel>(static_cast<uint32_t>(level) - value);
97 inline LogLevel& operator-=(LogLevel& level, uint32_t value) {
98 level = level - value;
103 * Construct a LogLevel from a string name.
105 LogLevel stringToLogLevel(folly::StringPiece name);
108 * Get a human-readable string representing the LogLevel.
110 std::string logLevelToString(LogLevel level);
113 * Print a LogLevel in a human readable format.
115 std::ostream& operator<<(std::ostream& os, LogLevel level);
118 * Returns true if and only if a LogLevel is fatal.
120 inline constexpr bool isLogLevelFatal(LogLevel level) {
121 return folly::kIsDebug ? (level >= LogLevel::DFATAL)
122 : (level >= LogLevel::FATAL);