2 // Copyright 2019 The Abseil Authors.
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
8 // https://www.apache.org/licenses/LICENSE-2.0
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.
16 // -----------------------------------------------------------------------------
17 // File: usage_config.h
18 // -----------------------------------------------------------------------------
20 // This file defines the main usage reporting configuration interfaces and
21 // documents Abseil's supported built-in usage flags. If these flags are found
22 // when parsing a command-line, Abseil will exit the program and display
23 // appropriate help messages.
24 #ifndef ABSL_FLAGS_USAGE_CONFIG_H_
25 #define ABSL_FLAGS_USAGE_CONFIG_H_
30 #include "absl/strings/string_view.h"
32 // -----------------------------------------------------------------------------
33 // Built-in Usage Flags
34 // -----------------------------------------------------------------------------
36 // Abseil supports the following built-in usage flags. When passed, these flags
37 // exit the program and :
40 // Shows help on important flags for this binary
42 // Shows help on all flags
44 // Shows help on only the main module for this program
46 // Shows help on all modules in the main package
48 // Shows the version and build info for this binary and exits
49 // * --only_check_args
50 // Exits after checking all flags
52 // Shows help on the modules named by this flag value
54 // Shows help on modules whose name contains the specified substring
58 namespace flags_internal {
59 using FlagKindFilter = std::function<bool (absl::string_view)>;
60 } // namespace flags_internal
64 // This structure contains the collection of callbacks for changing the behavior
65 // of the usage reporting routines in Abseil Flags.
66 struct FlagsUsageConfig {
67 // Returns true if flags defined in the given source code file should be
68 // reported with --helpshort flag. For example, if the file
69 // "path/to/my/code.cc" defines the flag "--my_flag", and
70 // contains_helpshort_flags("path/to/my/code.cc") returns true, invoking the
71 // program with --helpshort will include information about --my_flag in the
73 flags_internal::FlagKindFilter contains_helpshort_flags;
75 // Returns true if flags defined in the filename should be reported with
76 // --help flag. For example, if the file
77 // "path/to/my/code.cc" defines the flag "--my_flag", and
78 // contains_help_flags("path/to/my/code.cc") returns true, invoking the
79 // program with --help will include information about --my_flag in the
81 flags_internal::FlagKindFilter contains_help_flags;
83 // Returns true if flags defined in the filename should be reported with
84 // --helppackage flag. For example, if the file
85 // "path/to/my/code.cc" defines the flag "--my_flag", and
86 // contains_helppackage_flags("path/to/my/code.cc") returns true, invoking the
87 // program with --helppackage will include information about --my_flag in the
89 flags_internal::FlagKindFilter contains_helppackage_flags;
91 // Generates std::string containing program version. This is the std::string reported
92 // when user specifies --version in a command line.
93 std::function<std::string()> version_string;
95 // Normalizes the filename specific to the build system/filesystem used. This
96 // routine is used when we report the information about the flag definition
97 // location. For instance, if your build resides at some location you do not
98 // want to expose in the usage output, you can trim it to show only relevant
101 // normalize_filename("/my_company/some_long_path/src/project/file.cc")
103 // "project/file.cc".
104 std::function<std::string (absl::string_view)> normalize_filename;
107 // SetFlagsUsageConfig()
109 // Sets the usage reporting configuration callbacks. If any of the callbacks are
110 // not set in usage_config instance, then the default value of the callback is
112 void SetFlagsUsageConfig(FlagsUsageConfig usage_config);
114 namespace flags_internal {
116 FlagsUsageConfig GetUsageConfig();
118 void ReportUsageError(absl::string_view msg, bool is_fatal);
120 } // namespace flags_internal
125 // Additional report of fatal usage error message before we std::exit. Error is
126 // fatal if is_fatal argument to ReportUsageError is true.
127 void AbslInternalReportFatalUsageError(absl::string_view);
131 #endif // ABSL_FLAGS_USAGE_CONFIG_H_