// Copyright 2017 The Abseil Authors.

//

// 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

//

//      https://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.

#ifndef ABSL_BASE_LOG_SEVERITY_H_

#define ABSL_BASE_LOG_SEVERITY_H_

#include <array>

#include <ostream>

#include "absl/base/attributes.h"

#include "absl/base/config.h"

namespace absl {

ABSL_NAMESPACE_BEGIN

// absl::LogSeverity

//

// Four severity levels are defined. Logging APIs should terminate the program

// when a message is logged at severity `kFatal`; the other levels have no

// special semantics.

//

// Values other than the four defined levels (e.g. produced by `static_cast`)

// are valid, but their semantics when passed to a function, macro, or flag

// depend on the function, macro, or flag. The usual behavior is to normalize

// such values to a defined severity level, however in some cases values other

// than the defined levels are useful for comparison.

//

// Example:

//

//   // Effectively disables all logging:

//   SetMinLogLevel(static_cast<absl::LogSeverity>(100));

//

// Abseil flags may be defined with type `LogSeverity`. Dependency layering

// constraints require that the `AbslParseFlag()` overload be declared and

// defined in the flags library itself rather than here. The `AbslUnparseFlag()`

// overload is defined there as well for consistency.

//

// absl::LogSeverity Flag String Representation

//

// An `absl::LogSeverity` has a string representation used for parsing

// command-line flags based on the enumerator name (e.g. `kFatal`) or

// its unprefixed name (without the `k`) in any case-insensitive form. (E.g.

// "FATAL", "fatal" or "Fatal" are all valid.) Unparsing such flags produces an

// unprefixed string representation in all caps (e.g. "FATAL") or an integer.

//

// Additionally, the parser accepts arbitrary integers (as if the type were

// `int`).

//

// Examples:

//

//   --my_log_level=kInfo

//   --my_log_level=INFO

//   --my_log_level=info

//   --my_log_level=0

//

// `DFATAL` and `kLogDebugFatal` are similarly accepted.

//

// Unparsing a flag produces the same result as `absl::LogSeverityName()` for

// the standard levels and a base-ten integer otherwise.

enum class LogSeverity : int {

  kInfo = 0,

  kWarning = 1,

  kError = 2,

  kFatal = 3,

};

// LogSeverities()

//

// Returns an iterable of all standard `absl::LogSeverity` values, ordered from

// least to most severe.

constexpr std::array<absl::LogSeverity, 4> LogSeverities() {

  return {{absl::LogSeverity::kInfo, absl::LogSeverity::kWarning,

           absl::LogSeverity::kError, absl::LogSeverity::kFatal}};

}

// `absl::kLogDebugFatal` equals `absl::LogSeverity::kFatal` in debug builds

// (i.e. when `NDEBUG` is not defined) and `absl::LogSeverity::kError`

// otherwise.  Avoid ODR-using this variable as it has internal linkage and thus

// distinct storage in different TUs.

#ifdef NDEBUG

static constexpr absl::LogSeverity kLogDebugFatal = absl::LogSeverity::kError;

#else

static constexpr absl::LogSeverity kLogDebugFatal = absl::LogSeverity::kFatal;

#endif

// LogSeverityName()

//

// Returns the all-caps string representation (e.g. "INFO") of the specified

// severity level if it is one of the standard levels and "UNKNOWN" otherwise.

constexpr const char* LogSeverityName(absl::LogSeverity s) {

  switch (s) {

    case absl::LogSeverity::kInfo: return "INFO";

    case absl::LogSeverity::kWarning: return "WARNING";

    case absl::LogSeverity::kError: return "ERROR";

    case absl::LogSeverity::kFatal: return "FATAL";

  }

  return "UNKNOWN";

}

// NormalizeLogSeverity()

//

// Values less than `kInfo` normalize to `kInfo`; values greater than `kFatal`

// normalize to `kError` (**NOT** `kFatal`).

constexpr absl::LogSeverity NormalizeLogSeverity(absl::LogSeverity s) {

  absl::LogSeverity n = s;

  if (n < absl::LogSeverity::kInfo) n = absl::LogSeverity::kInfo;

  if (n > absl::LogSeverity::kFatal) n = absl::LogSeverity::kError;

  return n;

}

constexpr absl::LogSeverity NormalizeLogSeverity(int s) {

  return absl::NormalizeLogSeverity(static_cast<absl::LogSeverity>(s));

}

// operator<<

//

// The exact representation of a streamed `absl::LogSeverity` is deliberately

// unspecified; do not rely on it.

std::ostream& operator<<(std::ostream& os, absl::LogSeverity s);

// Enums representing a lower bound for LogSeverity. APIs that only operate on

// messages of at least a certain level (for example, `SetMinLogLevel()`) use

// this type to specify that level. absl::LogSeverityAtLeast::kInfinity is

// a level above all threshold levels and therefore no log message will

// ever meet this threshold.

enum class LogSeverityAtLeast : int {

  kInfo = static_cast<int>(absl::LogSeverity::kInfo),

  kWarning = static_cast<int>(absl::LogSeverity::kWarning),

  kError = static_cast<int>(absl::LogSeverity::kError),

  kFatal = static_cast<int>(absl::LogSeverity::kFatal),

  kInfinity = 1000,

};

std::ostream& operator<<(std::ostream& os, absl::LogSeverityAtLeast s);

// Enums representing an upper bound for LogSeverity. APIs that only operate on

// messages of at most a certain level (for example, buffer all messages at or

// below a certain level) use this type to specify that level.

// absl::LogSeverityAtMost::kNegativeInfinity is a level below all threshold

// levels and therefore will exclude all log messages.

enum class LogSeverityAtMost : int {

  kNegativeInfinity = -1000,

  kInfo = static_cast<int>(absl::LogSeverity::kInfo),

  kWarning = static_cast<int>(absl::LogSeverity::kWarning),

  kError = static_cast<int>(absl::LogSeverity::kError),

  kFatal = static_cast<int>(absl::LogSeverity::kFatal),

};

std::ostream& operator<<(std::ostream& os, absl::LogSeverityAtMost s);

#define COMPOP(op1, op2, T)                                         \

  constexpr bool operator op1(absl::T lhs, absl::LogSeverity rhs) { \

    return static_cast<absl::LogSeverity>(lhs) op1 rhs;             \

  }                                                                 \

Unexecuted instantiation: absl::operator>(absl::LogSeverityAtLeast, absl::LogSeverity)

Unexecuted instantiation: absl::operator<=(absl::LogSeverityAtLeast, absl::LogSeverity)

Unexecuted instantiation: absl::operator<(absl::LogSeverityAtMost, absl::LogSeverity)

Unexecuted instantiation: absl::operator>=(absl::LogSeverityAtMost, absl::LogSeverity)

  constexpr bool operator op2(absl::LogSeverity lhs, absl::T rhs) { \

    return lhs op2 static_cast<absl::LogSeverity>(rhs);             \

  }

Unexecuted instantiation: absl::operator<(absl::LogSeverity, absl::LogSeverityAtLeast)

Unexecuted instantiation: absl::operator>=(absl::LogSeverity, absl::LogSeverityAtLeast)

Unexecuted instantiation: absl::operator>(absl::LogSeverity, absl::LogSeverityAtMost)

Unexecuted instantiation: absl::operator<=(absl::LogSeverity, absl::LogSeverityAtMost)

// Comparisons between `LogSeverity` and `LogSeverityAtLeast`/

// `LogSeverityAtMost` are only supported in one direction.

// Valid checks are:

//   LogSeverity >= LogSeverityAtLeast

//   LogSeverity < LogSeverityAtLeast

//   LogSeverity <= LogSeverityAtMost

//   LogSeverity > LogSeverityAtMost

COMPOP(>, <, LogSeverityAtLeast)

COMPOP(<=, >=, LogSeverityAtLeast)

COMPOP(<, >, LogSeverityAtMost)

COMPOP(>=, <=, LogSeverityAtMost)

#undef COMPOP

ABSL_NAMESPACE_END

}  // namespace absl

#endif  // ABSL_BASE_LOG_SEVERITY_H_