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/commandlineflag.h" 24 #include "absl/flags/declare.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 // Streams the help message describing `flag` to `out`. 40 // The default value for `flag` is included in the output. 41 void FlagHelp(std::ostream& out, const CommandLineFlag& flag, 42 HelpFormat format = HelpFormat::kHumanReadable); 43 44 // Produces the help messages for all flags matching the filter. A flag matches 45 // the filter if it is defined in a file with a filename which includes 46 // filter string as a substring. You can use '/' and '.' to restrict the 47 // matching to a specific file names. For example: 48 // FlagsHelp(out, "/path/to/file."); 49 // restricts help to only flags which resides in files named like: 50 // .../path/to/file.<ext> 51 // for any extension 'ext'. If the filter is empty this function produces help 52 // messages for all flags. 53 void FlagsHelp(std::ostream& out, absl::string_view filter, 54 HelpFormat format, absl::string_view program_usage_message); 55 56 // -------------------------------------------------------------------- 57 58 // If any of the 'usage' related command line flags (listed on the bottom of 59 // this file) has been set this routine produces corresponding help message in 60 // the specified output stream and returns: 61 // 0 - if "version" or "only_check_flags" flags were set and handled. 62 // 1 - if some other 'usage' related flag was set and handled. 63 // -1 - if no usage flags were set on a commmand line. 64 // Non negative return values are expected to be used as an exit code for a 65 // binary. 66 int HandleUsageFlags(std::ostream& out, 67 absl::string_view program_usage_message); 68 69 // -------------------------------------------------------------------- 70 // Globals representing usage reporting flags 71 72 enum class HelpMode { 73 kNone, 74 kImportant, 75 kShort, 76 kFull, 77 kPackage, 78 kMatch, 79 kVersion, 80 kOnlyCheckArgs 81 }; 82 83 // Returns substring to filter help output (--help=substr argument) 84 std::string GetFlagsHelpMatchSubstr(); 85 // Returns the requested help mode. 86 HelpMode GetFlagsHelpMode(); 87 // Returns the requested help format. 88 HelpFormat GetFlagsHelpFormat(); 89 90 // These are corresponding setters to the attributes above. 91 void SetFlagsHelpMatchSubstr(absl::string_view); 92 void SetFlagsHelpMode(HelpMode); 93 void SetFlagsHelpFormat(HelpFormat); 94 95 // Deduces usage flags from the input argument in a form --name=value or 96 // --name. argument is already split into name and value before we call this 97 // function. 98 bool DeduceUsageFlags(absl::string_view name, absl::string_view value); 99 100 } // namespace flags_internal 101 ABSL_NAMESPACE_END 102 } // namespace absl 103 104 #endif // ABSL_FLAGS_INTERNAL_USAGE_H_ 105