1 files changed, 53 insertions, 5 deletions

diff --git a/absl/base/log_severity.h b/absl/base/log_severity.h
index 45f79cca..65a3b166 100644
--- a/absl/base/log_severity.h
+++ b/absl/base/log_severity.h
@@ -19,13 +19,53 @@
 #include <ostream>
 
 #include "absl/base/attributes.h"
+#include "absl/base/config.h"
 
 namespace absl {
-inline namespace lts_2019_08_08 {
+ABSL_NAMESPACE_BEGIN
 
-// Four severity levels are defined.  Logging APIs should terminate the program
+// 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.
+//
+// Exmaple:
+//
+//   // 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
+//
+// 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,
@@ -33,6 +73,8 @@ enum class LogSeverity : int {
   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() {
@@ -40,8 +82,10 @@ constexpr std::array<absl::LogSeverity, 4> LogSeverities() {
            absl::LogSeverity::kError, absl::LogSeverity::kFatal}};
 }
 
+// LogSeverityName()
+//
 // Returns the all-caps string representation (e.g. "INFO") of the specified
-// severity level if it is one of the normal levels and "UNKNOWN" otherwise.
+// severity level if it is one of the standard levels and "UNKNOWN" otherwise.
 constexpr const char* LogSeverityName(absl::LogSeverity s) {
   return s == absl::LogSeverity::kInfo
              ? "INFO"
@@ -52,6 +96,8 @@ constexpr const char* LogSeverityName(absl::LogSeverity s) {
                          : s == absl::LogSeverity::kFatal ? "FATAL" : "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) {
@@ -60,14 +106,16 @@ constexpr absl::LogSeverity NormalizeLogSeverity(absl::LogSeverity s) {
              : s > absl::LogSeverity::kFatal ? absl::LogSeverity::kError : s;
 }
 constexpr absl::LogSeverity NormalizeLogSeverity(int s) {
-  return NormalizeLogSeverity(static_cast<absl::LogSeverity>(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);
 
-}  // inline namespace lts_2019_08_08
+ABSL_NAMESPACE_END
 }  // namespace absl
 
 #endif  // ABSL_BASE_INTERNAL_LOG_SEVERITY_H_