usage.h (3683B)
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 <ostream> 21 #include <string> 22 23 #include "absl/base/config.h" 24 #include "absl/flags/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 // The kind of usage help requested. 40 enum class HelpMode { 41 kNone, 42 kImportant, 43 kShort, 44 kFull, 45 kPackage, 46 kMatch, 47 kVersion, 48 kOnlyCheckArgs 49 }; 50 51 // Streams the help message describing `flag` to `out`. 52 // The default value for `flag` is included in the output. 53 void FlagHelp(std::ostream& out, const CommandLineFlag& flag, 54 HelpFormat format = HelpFormat::kHumanReadable); 55 56 // Produces the help messages for all flags matching the filter. A flag matches 57 // the filter if it is defined in a file with a filename which includes 58 // filter string as a substring. You can use '/' and '.' to restrict the 59 // matching to a specific file names. For example: 60 // FlagsHelp(out, "/path/to/file."); 61 // restricts help to only flags which resides in files named like: 62 // .../path/to/file.<ext> 63 // for any extension 'ext'. If the filter is empty this function produces help 64 // messages for all flags. 65 void FlagsHelp(std::ostream& out, absl::string_view filter, 66 HelpFormat format, absl::string_view program_usage_message); 67 68 // -------------------------------------------------------------------- 69 70 // If any of the 'usage' related command line flags (listed on the bottom of 71 // this file) has been set this routine produces corresponding help message in 72 // the specified output stream and returns HelpMode that was handled. Otherwise 73 // it returns HelpMode::kNone. 74 HelpMode HandleUsageFlags(std::ostream& out, 75 absl::string_view program_usage_message); 76 77 // -------------------------------------------------------------------- 78 // Encapsulates the logic of exiting the binary depending on handled help mode. 79 80 void MaybeExit(HelpMode mode); 81 82 // -------------------------------------------------------------------- 83 // Globals representing usage reporting flags 84 85 // Returns substring to filter help output (--help=substr argument) 86 std::string GetFlagsHelpMatchSubstr(); 87 // Returns the requested help mode. 88 HelpMode GetFlagsHelpMode(); 89 // Returns the requested help format. 90 HelpFormat GetFlagsHelpFormat(); 91 92 // These are corresponding setters to the attributes above. 93 void SetFlagsHelpMatchSubstr(absl::string_view); 94 void SetFlagsHelpMode(HelpMode); 95 void SetFlagsHelpFormat(HelpFormat); 96 97 // Deduces usage flags from the input argument in a form --name=value or 98 // --name. argument is already split into name and value before we call this 99 // function. 100 bool DeduceUsageFlags(absl::string_view name, absl::string_view value); 101 102 } // namespace flags_internal 103 ABSL_NAMESPACE_END 104 } // namespace absl 105 106 #endif // ABSL_FLAGS_INTERNAL_USAGE_H_