about summary refs log tree commit diff
path: root/third_party/abseil_cpp/absl/flags/internal/usage.cc
blob: 10accc46f32a13b8a1807e6a9410d35fd5e3b64a (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
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
//
// 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.

#include "absl/flags/internal/usage.h"

#include <functional>
#include <map>
#include <ostream>
#include <string>
#include <utility>
#include <vector>

#include "absl/base/config.h"
#include "absl/flags/flag.h"
#include "absl/flags/internal/commandlineflag.h"
#include "absl/flags/internal/flag.h"
#include "absl/flags/internal/path_util.h"
#include "absl/flags/internal/private_handle_accessor.h"
#include "absl/flags/internal/program_name.h"
#include "absl/flags/internal/registry.h"
#include "absl/flags/usage_config.h"
#include "absl/strings/str_cat.h"
#include "absl/strings/str_split.h"
#include "absl/strings/string_view.h"

ABSL_FLAG(bool, help, false,
          "show help on important flags for this binary [tip: all flags can "
          "have two dashes]");
ABSL_FLAG(bool, helpfull, false, "show help on all flags");
ABSL_FLAG(bool, helpshort, false,
          "show help on only the main module for this program");
ABSL_FLAG(bool, helppackage, false,
          "show help on all modules in the main package");
ABSL_FLAG(bool, version, false, "show version and build info and exit");
ABSL_FLAG(bool, only_check_args, false, "exit after checking all flags");
ABSL_FLAG(std::string, helpon, "",
          "show help on the modules named by this flag value");
ABSL_FLAG(std::string, helpmatch, "",
          "show help on modules whose name contains the specified substr");

namespace absl {
ABSL_NAMESPACE_BEGIN
namespace flags_internal {
namespace {

// This class is used to emit an XML element with `tag` and `text`.
// It adds opening and closing tags and escapes special characters in the text.
// For example:
// std::cout << XMLElement("title", "Milk & Cookies");
// prints "<title>Milk &amp; Cookies</title>"
class XMLElement {
 public:
  XMLElement(absl::string_view tag, absl::string_view txt)
      : tag_(tag), txt_(txt) {}

  friend std::ostream& operator<<(std::ostream& out,
                                  const XMLElement& xml_elem) {
    out << "<" << xml_elem.tag_ << ">";

    for (auto c : xml_elem.txt_) {
      switch (c) {
        case '"':
          out << "&quot;";
          break;
        case '\'':
          out << "&apos;";
          break;
        case '&':
          out << "&amp;";
          break;
        case '<':
          out << "&lt;";
          break;
        case '>':
          out << "&gt;";
          break;
        default:
          out << c;
          break;
      }
    }

    return out << "</" << xml_elem.tag_ << ">";
  }

 private:
  absl::string_view tag_;
  absl::string_view txt_;
};

// --------------------------------------------------------------------
// Helper class to pretty-print info about a flag.

class FlagHelpPrettyPrinter {
 public:
  // Pretty printer holds on to the std::ostream& reference to direct an output
  // to that stream.
  FlagHelpPrettyPrinter(int max_line_len, std::ostream* out)
      : out_(*out),
        max_line_len_(max_line_len),
        line_len_(0),
        first_line_(true) {}

  void Write(absl::string_view str, bool wrap_line = false) {
    // Empty string - do nothing.
    if (str.empty()) return;

    std::vector<absl::string_view> tokens;
    if (wrap_line) {
      for (auto line : absl::StrSplit(str, absl::ByAnyChar("\n\r"))) {
        if (!tokens.empty()) {
          // Keep line separators in the input string.
          tokens.push_back("\n");
        }
        for (auto token :
             absl::StrSplit(line, absl::ByAnyChar(" \t"), absl::SkipEmpty())) {
          tokens.push_back(token);
        }
      }
    } else {
      tokens.push_back(str);
    }

    for (auto token : tokens) {
      bool new_line = (line_len_ == 0);

      // Respect line separators in the input string.
      if (token == "\n") {
        EndLine();
        continue;
      }

      // Write the token, ending the string first if necessary/possible.
      if (!new_line && (line_len_ + token.size() >= max_line_len_)) {
        EndLine();
        new_line = true;
      }

      if (new_line) {
        StartLine();
      } else {
        out_ << ' ';
        ++line_len_;
      }

      out_ << token;
      line_len_ += token.size();
    }
  }

  void StartLine() {
    if (first_line_) {
      out_ << "    ";
      line_len_ = 4;
      first_line_ = false;
    } else {
      out_ << "      ";
      line_len_ = 6;
    }
  }
  void EndLine() {
    out_ << '\n';
    line_len_ = 0;
  }

 private:
  std::ostream& out_;
  const int max_line_len_;
  int line_len_;
  bool first_line_;
};

void FlagHelpHumanReadable(const flags_internal::CommandLineFlag& flag,
                           std::ostream* out) {
  FlagHelpPrettyPrinter printer(80, out);  // Max line length is 80.

  // Flag name.
  printer.Write(absl::StrCat("--", flag.Name()));

  // Flag help.
  printer.Write(absl::StrCat("(", flag.Help(), ");"), /*wrap_line=*/true);

  // The listed default value will be the actual default from the flag
  // definition in the originating source file, unless the value has
  // subsequently been modified using SetCommandLineOption() with mode
  // SET_FLAGS_DEFAULT.
  std::string dflt_val = flag.DefaultValue();
  std::string curr_val = flag.CurrentValue();
  bool is_modified = curr_val != dflt_val;

  if (flag.IsOfType<std::string>()) {
    dflt_val = absl::StrCat("\"", dflt_val, "\"");
  }
  printer.Write(absl::StrCat("default: ", dflt_val, ";"));

  if (is_modified) {
    if (flag.IsOfType<std::string>()) {
      curr_val = absl::StrCat("\"", curr_val, "\"");
    }
    printer.Write(absl::StrCat("currently: ", curr_val, ";"));
  }

  printer.EndLine();
}

// Shows help for every filename which matches any of the filters
// If filters are empty, shows help for every file.
// If a flag's help message has been stripped (e.g. by adding '#define
// STRIP_FLAG_HELP 1' then this flag will not be displayed by '--help'
// and its variants.
void FlagsHelpImpl(std::ostream& out, flags_internal::FlagKindFilter filter_cb,
                   HelpFormat format, absl::string_view program_usage_message) {
  if (format == HelpFormat::kHumanReadable) {
    out << flags_internal::ShortProgramInvocationName() << ": "
        << program_usage_message << "\n\n";
  } else {
    // XML schema is not a part of our public API for now.
    out << "<?xml version=\"1.0\"?>\n"
        << "<!-- This output should be used with care. We do not report type "
           "names for flags with user defined types -->\n"
        << "<!-- Prefer flag only_check_args for validating flag inputs -->\n"
        // The document.
        << "<AllFlags>\n"
        // The program name and usage.
        << XMLElement("program", flags_internal::ShortProgramInvocationName())
        << '\n'
        << XMLElement("usage", program_usage_message) << '\n';
  }

  // Map of package name to
  //   map of file name to
  //     vector of flags in the file.
  // This map is used to output matching flags grouped by package and file
  // name.
  std::map<std::string,
           std::map<std::string,
                    std::vector<const flags_internal::CommandLineFlag*>>>
      matching_flags;

  flags_internal::ForEachFlag([&](flags_internal::CommandLineFlag* flag) {
    std::string flag_filename = flag->Filename();

    // Ignore retired flags.
    if (flag->IsRetired()) return;

    // If the flag has been stripped, pretend that it doesn't exist.
    if (flag->Help() == flags_internal::kStrippedFlagHelp) return;

    // Make sure flag satisfies the filter
    if (!filter_cb || !filter_cb(flag_filename)) return;

    matching_flags[std::string(flags_internal::Package(flag_filename))]
                  [flag_filename]
                      .push_back(flag);
  });

  absl::string_view
      package_separator;             // controls blank lines between packages.
  absl::string_view file_separator;  // controls blank lines between files.
  for (const auto& package : matching_flags) {
    if (format == HelpFormat::kHumanReadable) {
      out << package_separator;
      package_separator = "\n\n";
    }

    file_separator = "";
    for (const auto& flags_in_file : package.second) {
      if (format == HelpFormat::kHumanReadable) {
        out << file_separator << "  Flags from " << flags_in_file.first
            << ":\n";
        file_separator = "\n";
      }

      for (const auto* flag : flags_in_file.second) {
        flags_internal::FlagHelp(out, *flag, format);
      }
    }
  }

  if (format == HelpFormat::kHumanReadable) {
    if (filter_cb && matching_flags.empty()) {
      out << "  No modules matched: use -helpfull\n";
    }
  } else {
    // The end of the document.
    out << "</AllFlags>\n";
  }
}

}  // namespace

// --------------------------------------------------------------------
// Produces the help message describing specific flag.
void FlagHelp(std::ostream& out, const flags_internal::CommandLineFlag& flag,
              HelpFormat format) {
  if (format == HelpFormat::kHumanReadable)
    flags_internal::FlagHelpHumanReadable(flag, &out);
}

// --------------------------------------------------------------------
// Produces the help messages for all flags matching the filter.
// If filter is empty produces help messages for all flags.
void FlagsHelp(std::ostream& out, absl::string_view filter, HelpFormat format,
               absl::string_view program_usage_message) {
  flags_internal::FlagKindFilter filter_cb = [&](absl::string_view filename) {
    return filter.empty() || filename.find(filter) != absl::string_view::npos;
  };
  flags_internal::FlagsHelpImpl(out, filter_cb, format, program_usage_message);
}

// --------------------------------------------------------------------
// Checks all the 'usage' command line flags to see if any have been set.
// If so, handles them appropriately.
int HandleUsageFlags(std::ostream& out,
                     absl::string_view program_usage_message) {
  if (absl::GetFlag(FLAGS_helpshort)) {
    flags_internal::FlagsHelpImpl(
        out, flags_internal::GetUsageConfig().contains_helpshort_flags,
        HelpFormat::kHumanReadable, program_usage_message);
    return 1;
  }

  if (absl::GetFlag(FLAGS_helpfull)) {
    // show all options
    flags_internal::FlagsHelp(out, "", HelpFormat::kHumanReadable,
                              program_usage_message);
    return 1;
  }

  if (!absl::GetFlag(FLAGS_helpon).empty()) {
    flags_internal::FlagsHelp(
        out, absl::StrCat("/", absl::GetFlag(FLAGS_helpon), "."),
        HelpFormat::kHumanReadable, program_usage_message);
    return 1;
  }

  if (!absl::GetFlag(FLAGS_helpmatch).empty()) {
    flags_internal::FlagsHelp(out, absl::GetFlag(FLAGS_helpmatch),
                              HelpFormat::kHumanReadable,
                              program_usage_message);
    return 1;
  }

  if (absl::GetFlag(FLAGS_help)) {
    flags_internal::FlagsHelpImpl(
        out, flags_internal::GetUsageConfig().contains_help_flags,
        HelpFormat::kHumanReadable, program_usage_message);

    out << "\nTry --helpfull to get a list of all flags.\n";

    return 1;
  }

  if (absl::GetFlag(FLAGS_helppackage)) {
    flags_internal::FlagsHelpImpl(
        out, flags_internal::GetUsageConfig().contains_helppackage_flags,
        HelpFormat::kHumanReadable, program_usage_message);

    out << "\nTry --helpfull to get a list of all flags.\n";

    return 1;
  }

  if (absl::GetFlag(FLAGS_version)) {
    if (flags_internal::GetUsageConfig().version_string)
      out << flags_internal::GetUsageConfig().version_string();
    // Unlike help, we may be asking for version in a script, so return 0
    return 0;
  }

  if (absl::GetFlag(FLAGS_only_check_args)) {
    return 0;
  }

  return -1;
}

}  // namespace flags_internal
ABSL_NAMESPACE_END
}  // namespace absl