merge(3p/absl): subtree merge of Abseil up to e19260f r/1889

... notably, this includes Abseil's own StatusOr type, which
conflicted with our implementation (that was taken from TensorFlow).

Change-Id: Ie7d6764b64055caaeb8dc7b6b9d066291e6b538f

1 files changed, 33 insertions, 10 deletions

diff --git a/third_party/abseil_cpp/absl/flags/internal/usage.h b/third_party/abseil_cpp/absl/flags/internal/usage.h
index 0c62dc4b2a..c0bcac5762 100644
--- a/third_party/abseil_cpp/absl/flags/internal/usage.h
+++ b/third_party/abseil_cpp/absl/flags/internal/usage.h
@@ -36,7 +36,8 @@ enum class HelpFormat {
   kHumanReadable,
 };
 
-// Outputs the help message describing specific flag.
+// Streams the help message describing `flag` to `out`.
+// The default value for `flag` is included in the output.
 void FlagHelp(std::ostream& out, const CommandLineFlag& flag,
               HelpFormat format = HelpFormat::kHumanReadable);
 
@@ -65,17 +66,39 @@ void FlagsHelp(std::ostream& out, absl::string_view filter,
 int HandleUsageFlags(std::ostream& out,
                      absl::string_view program_usage_message);
 
+// --------------------------------------------------------------------
+// Globals representing usage reporting flags
+
+enum class HelpMode {
+  kNone,
+  kImportant,
+  kShort,
+  kFull,
+  kPackage,
+  kMatch,
+  kVersion,
+  kOnlyCheckArgs
+};
+
+// Returns substring to filter help output (--help=substr argument)
+std::string GetFlagsHelpMatchSubstr();
+// Returns the requested help mode.
+HelpMode GetFlagsHelpMode();
+// Returns the requested help format.
+HelpFormat GetFlagsHelpFormat();
+
+// These are corresponding setters to the attributes above.
+void SetFlagsHelpMatchSubstr(absl::string_view);
+void SetFlagsHelpMode(HelpMode);
+void SetFlagsHelpFormat(HelpFormat);
+
+// Deduces usage flags from the input argument in a form --name=value or
+// --name. argument is already split into name and value before we call this
+// function.
+bool DeduceUsageFlags(absl::string_view name, absl::string_view value);
+
 }  // namespace flags_internal
 ABSL_NAMESPACE_END
 }  // namespace absl
 
-ABSL_DECLARE_FLAG(bool, help);
-ABSL_DECLARE_FLAG(bool, helpfull);
-ABSL_DECLARE_FLAG(bool, helpshort);
-ABSL_DECLARE_FLAG(bool, helppackage);
-ABSL_DECLARE_FLAG(bool, version);
-ABSL_DECLARE_FLAG(bool, only_check_args);
-ABSL_DECLARE_FLAG(std::string, helpon);
-ABSL_DECLARE_FLAG(std::string, helpmatch);
-
 #endif  // ABSL_FLAGS_INTERNAL_USAGE_H_