about summary refs log tree commit diff
path: root/absl/flags/usage_config.h
blob: 0ed7e1b47c0c5d48dfa95f5e922728c6bd45c851 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
//
//  Copyright 2019 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// -----------------------------------------------------------------------------
// File: usage_config.h
// -----------------------------------------------------------------------------
//
// This file defines the main usage reporting configuration interfaces and
// documents Abseil's supported built-in usage flags. If these flags are found
// when parsing a command-line, Abseil will exit the program and display
// appropriate help messages.
#ifndef ABSL_FLAGS_USAGE_CONFIG_H_
#define ABSL_FLAGS_USAGE_CONFIG_H_

#include <functional>
#include <string>

#include "absl/base/config.h"
#include "absl/strings/string_view.h"

// -----------------------------------------------------------------------------
// Built-in Usage Flags
// -----------------------------------------------------------------------------
//
// Abseil supports the following built-in usage flags. When passed, these flags
// exit the program and :
//
// * --help
//     Shows help on important flags for this binary
// * --helpfull
//     Shows help on all flags
// * --helpshort
//     Shows help on only the main module for this program
// * --helppackage
//     Shows help on all modules in the main package
// * --version
//     Shows the version and build info for this binary and exits
// * --only_check_args
//     Exits after checking all flags
// * --helpon
//     Shows help on the modules named by this flag value
// * --helpmatch
//     Shows help on modules whose name contains the specified substring

namespace absl {
ABSL_NAMESPACE_BEGIN

namespace flags_internal {
using FlagKindFilter = std::function<bool (absl::string_view)>;
}  // namespace flags_internal

// FlagsUsageConfig
//
// This structure contains the collection of callbacks for changing the behavior
// of the usage reporting routines in Abseil Flags.
struct FlagsUsageConfig {
  // Returns true if flags defined in the given source code file should be
  // reported with --helpshort flag. For example, if the file
  // "path/to/my/code.cc" defines the flag "--my_flag", and
  // contains_helpshort_flags("path/to/my/code.cc") returns true, invoking the
  // program with --helpshort will include information about --my_flag in the
  // program output.
  flags_internal::FlagKindFilter contains_helpshort_flags;

  // Returns true if flags defined in the filename should be reported with
  // --help flag. For example, if the file
  // "path/to/my/code.cc" defines the flag "--my_flag", and
  // contains_help_flags("path/to/my/code.cc") returns true, invoking the
  // program with --help will include information about --my_flag in the
  // program output.
  flags_internal::FlagKindFilter contains_help_flags;

  // Returns true if flags defined in the filename should be reported with
  // --helppackage flag. For example, if the file
  // "path/to/my/code.cc" defines the flag "--my_flag", and
  // contains_helppackage_flags("path/to/my/code.cc") returns true, invoking the
  // program with --helppackage will include information about --my_flag in the
  // program output.
  flags_internal::FlagKindFilter contains_helppackage_flags;

  // Generates std::string containing program version. This is the std::string reported
  // when user specifies --version in a command line.
  std::function<std::string()> version_string;

  // Normalizes the filename specific to the build system/filesystem used. This
  // routine is used when we report the information about the flag definition
  // location. For instance, if your build resides at some location you do not
  // want to expose in the usage output, you can trim it to show only relevant
  // part.
  // For example:
  //   normalize_filename("/my_company/some_long_path/src/project/file.cc")
  // might produce
  //   "project/file.cc".
  std::function<std::string(absl::string_view)> normalize_filename;
};

// SetFlagsUsageConfig()
//
// Sets the usage reporting configuration callbacks. If any of the callbacks are
// not set in usage_config instance, then the default value of the callback is
// used.
void SetFlagsUsageConfig(FlagsUsageConfig usage_config);

namespace flags_internal {

FlagsUsageConfig GetUsageConfig();

void ReportUsageError(absl::string_view msg, bool is_fatal);

}  // namespace flags_internal
ABSL_NAMESPACE_END
}  // namespace absl

extern "C" {

// Additional report of fatal usage error message before we std::exit. Error is
// fatal if is_fatal argument to ReportUsageError is true.
void AbslInternalReportFatalUsageError(absl::string_view);

}  // extern "C"

#endif  // ABSL_FLAGS_USAGE_CONFIG_H_