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.
22 #include <folly/Range.h>
29 * Higher levels are more important than lower ones.
31 * However, the numbers in the DBG* level names are reversed, and can be
32 * thought of as debug verbosity levels. Increasing DBG* numbers mean
33 * increasing level of verbosity. DBG0 is the least verbose debug level,
34 * DBG1 is one level higher of verbosity, etc.
36 enum class LogLevel : uint32_t {
57 // Unfortunately Windows headers #define ERROR
58 // On Windows platforms we avoid defining ERROR. However we make it
59 // available on other platforms, to make it easier to convert code from
60 // other log libraries that also use ERROR as their log level name (e.g.,
69 // The most significant bit is used by LogCategory to store a flag value,
70 // so the maximum value has that bit cleared.
72 // (We call this MAX_LEVEL instead of MAX just since MAX() is commonly
73 // defined as a preprocessor macro by some C headers.)
74 MAX_LEVEL = 0x7fffffff,
78 * Support adding and subtracting integers from LogLevels, to create slightly
79 * adjusted log level values.
81 inline LogLevel operator+(LogLevel level, uint32_t value) {
82 auto newValue = static_cast<uint32_t>(level) + value;
83 // Cap the result at LogLevel::MAX_LEVEL
84 if (newValue > static_cast<uint32_t>(LogLevel::MAX_LEVEL)) {
85 return LogLevel::MAX_LEVEL;
87 return static_cast<LogLevel>(newValue);
89 inline LogLevel& operator+=(LogLevel& level, uint32_t value) {
90 level = level + value;
93 inline LogLevel operator-(LogLevel level, uint32_t value) {
94 return static_cast<LogLevel>(static_cast<uint32_t>(level) - value);
96 inline LogLevel& operator-=(LogLevel& level, uint32_t value) {
97 level = level - value;
102 * Comparisons between LogLevel values
104 inline bool operator<=(LogLevel a, LogLevel b) {
105 return static_cast<uint32_t>(a) <= static_cast<uint32_t>(b);
107 inline bool operator<(LogLevel a, LogLevel b) {
108 return static_cast<uint32_t>(a) < static_cast<uint32_t>(b);
110 inline bool operator>=(LogLevel a, LogLevel b) {
111 return static_cast<uint32_t>(a) >= static_cast<uint32_t>(b);
113 inline bool operator>(LogLevel a, LogLevel b) {
114 return static_cast<uint32_t>(a) > static_cast<uint32_t>(b);
118 * Construct a LogLevel from a string name.
120 LogLevel stringToLogLevel(folly::StringPiece name);
123 * Get a human-readable string representing the LogLevel.
125 std::string logLevelToString(LogLevel level);
128 * Print a LogLevel in a human readable format.
130 std::ostream& operator<<(std::ostream& os, LogLevel level);