1 // 2 // Copyright 2019 The Abseil Authors. 3 // 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 7 // 8 // https://www.apache.org/licenses/LICENSE-2.0 9 // 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. 15 16 #ifndef ABSL_FLAGS_INTERNAL_USAGE_H_ 17 #define ABSL_FLAGS_INTERNAL_USAGE_H_ 18 19 #include <iosfwd> 20 #include <string> 21 22 #include "absl/base/config.h" 23 #include "absl/flags/declare.h" 24 #include "absl/flags/internal/commandlineflag.h" 25 #include "absl/strings/string_view.h" 26 27 // -------------------------------------------------------------------- 28 // Usage reporting interfaces 29 30 namespace absl { 31 ABSL_NAMESPACE_BEGIN 32 namespace flags_internal { 33 34 // The format to report the help messages in. 35 enum class HelpFormat { 36 kHumanReadable, 37 }; 38 39 // Outputs the help message describing specific flag. 40 void FlagHelp(std::ostream& out, const flags_internal::CommandLineFlag& flag, 41 HelpFormat format = HelpFormat::kHumanReadable); 42 43 // Produces the help messages for all flags matching the filter. A flag matches 44 // the filter if it is defined in a file with a filename which includes 45 // filter string as a substring. You can use '/' and '.' to restrict the 46 // matching to a specific file names. For example: 47 // FlagsHelp(out, "/path/to/file."); 48 // restricts help to only flags which resides in files named like: 49 // .../path/to/file.<ext> 50 // for any extension 'ext'. If the filter is empty this function produces help 51 // messages for all flags. 52 void FlagsHelp(std::ostream& out, absl::string_view filter, 53 HelpFormat format, absl::string_view program_usage_message); 54 55 // -------------------------------------------------------------------- 56 57 // If any of the 'usage' related command line flags (listed on the bottom of 58 // this file) has been set this routine produces corresponding help message in 59 // the specified output stream and returns: 60 // 0 - if "version" or "only_check_flags" flags were set and handled. 61 // 1 - if some other 'usage' related flag was set and handled. 62 // -1 - if no usage flags were set on a commmand line. 63 // Non negative return values are expected to be used as an exit code for a 64 // binary. 65 int HandleUsageFlags(std::ostream& out, 66 absl::string_view program_usage_message); 67 68 } // namespace flags_internal 69 ABSL_NAMESPACE_END 70 } // namespace absl 71 72 ABSL_DECLARE_FLAG(bool, help); 73 ABSL_DECLARE_FLAG(bool, helpfull); 74 ABSL_DECLARE_FLAG(bool, helpshort); 75 ABSL_DECLARE_FLAG(bool, helppackage); 76 ABSL_DECLARE_FLAG(bool, version); 77 ABSL_DECLARE_FLAG(bool, only_check_args); 78 ABSL_DECLARE_FLAG(std::string, helpon); 79 ABSL_DECLARE_FLAG(std::string, helpmatch); 80 81 #endif // ABSL_FLAGS_INTERNAL_USAGE_H_ 82