path: root/contrib/restricted/abseil-cpp/absl/flags/internal/usage.cc

//
// 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 <stdint.h>

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

#include "absl/base/config.h"
#include "absl/flags/commandlineflag.h"
#include "absl/flags/flag.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"

// Dummy global variables to prevent anyone else defining these. 
bool FLAGS_help = false; 
bool FLAGS_helpfull = false; 
bool FLAGS_helpshort = false; 
bool FLAGS_helppackage = false; 
bool FLAGS_version = false; 
bool FLAGS_only_check_args = false; 
bool FLAGS_helpon = false; 
bool FLAGS_helpmatch = false; 

namespace absl {
ABSL_NAMESPACE_BEGIN
namespace flags_internal {
namespace {

using PerFlagFilter = std::function<bool(const absl::CommandLineFlag&)>; 
 
// Maximum length size in a human readable format. 
constexpr size_t kHrfMaxLineLength = 80; 
 
// 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(size_t max_line_len, size_t min_line_len, 
                        size_t wrapped_line_indent, std::ostream& out) 
      : out_(out),
        max_line_len_(max_line_len),
        min_line_len_(min_line_len), 
        wrapped_line_indent_(wrapped_line_indent), 
        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_ + static_cast<int>(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_) {
      line_len_ = min_line_len_; 
      first_line_ = false;
    } else {
      line_len_ = min_line_len_ + wrapped_line_indent_; 
    }
    out_ << std::string(line_len_, ' '); 
  }
  void EndLine() {
    out_ << '\n';
    line_len_ = 0;
  }

 private:
  std::ostream& out_;
  const size_t max_line_len_; 
  const size_t min_line_len_; 
  const size_t wrapped_line_indent_; 
  size_t line_len_; 
  bool first_line_;
};

void FlagHelpHumanReadable(const CommandLineFlag& flag, std::ostream& out) {
  FlagHelpPrettyPrinter printer(kHrfMaxLineLength, 4, 2, out); 

  // 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, PerFlagFilter 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';
  }

  // Ordered 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 absl::CommandLineFlag*>>>
      matching_flags;

  flags_internal::ForEachFlag([&](absl::CommandLineFlag& flag) {
    // 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(flag)) return; 
 
    std::string flag_filename = flag.Filename();

    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 (auto& package : matching_flags) {
    if (format == HelpFormat::kHumanReadable) {
      out << package_separator;
      package_separator = "\n\n";
    }

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

      std::sort(std::begin(flags_in_file.second),
                std::end(flags_in_file.second),
                [](const CommandLineFlag* lhs, const CommandLineFlag* rhs) {
                  return lhs->Name() < rhs->Name();
                });

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

  if (format == HelpFormat::kHumanReadable) {
    FlagHelpPrettyPrinter printer(kHrfMaxLineLength, 0, 0, out); 
 
    if (filter_cb && matching_flags.empty()) {
      printer.Write("No flags matched.\n", true); 
    }
    printer.EndLine(); 
    printer.Write( 
        "Try --helpfull to get a list of all flags or --help=substring " 
        "shows help for flags which include specified substring in either " 
        "in the name, or description or path.\n", 
        true); 
  } else {
    // The end of the document.
    out << "</AllFlags>\n";
  }
}

void FlagsHelpImpl(std::ostream& out, 
                   flags_internal::FlagKindFilter filename_filter_cb, 
                   HelpFormat format, absl::string_view program_usage_message) { 
  FlagsHelpImpl( 
      out, 
      [&](const absl::CommandLineFlag& flag) { 
        return filename_filter_cb && filename_filter_cb(flag.Filename()); 
      }, 
      format, program_usage_message); 
} 
 
}  // namespace

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

// --------------------------------------------------------------------
// Produces the help messages for all flags matching the filename 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) {
  switch (GetFlagsHelpMode()) { 
    case HelpMode::kNone: 
      break; 
    case HelpMode::kImportant: 
      flags_internal::FlagsHelpImpl( 
          out, flags_internal::GetUsageConfig().contains_help_flags, 
          GetFlagsHelpFormat(), program_usage_message); 
      return 1; 

    case HelpMode::kShort: 
      flags_internal::FlagsHelpImpl( 
          out, flags_internal::GetUsageConfig().contains_helpshort_flags, 
          GetFlagsHelpFormat(), program_usage_message); 
      return 1; 

    case HelpMode::kFull: 
      flags_internal::FlagsHelp(out, "", GetFlagsHelpFormat(), 
                                program_usage_message); 
      return 1; 

    case HelpMode::kPackage: 
      flags_internal::FlagsHelpImpl( 
          out, flags_internal::GetUsageConfig().contains_helppackage_flags, 
          GetFlagsHelpFormat(), program_usage_message); 

      return 1; 

    case HelpMode::kMatch: { 
      std::string substr = GetFlagsHelpMatchSubstr(); 
      if (substr.empty()) { 
        // show all options 
        flags_internal::FlagsHelp(out, substr, GetFlagsHelpFormat(), 
                                  program_usage_message); 
      } else { 
        auto filter_cb = [&substr](const absl::CommandLineFlag& flag) { 
          if (absl::StrContains(flag.Name(), substr)) return true; 
          if (absl::StrContains(flag.Filename(), substr)) return true; 
          if (absl::StrContains(flag.Help(), substr)) return true; 

          return false; 
        }; 
        flags_internal::FlagsHelpImpl( 
            out, filter_cb, HelpFormat::kHumanReadable, program_usage_message); 
      } 
 
      return 1; 
    } 
    case HelpMode::kVersion: 
      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; 
 
    case HelpMode::kOnlyCheckArgs: 
      return 0; 
  }

  return -1; 
} 

// -------------------------------------------------------------------- 
// Globals representing usage reporting flags 

namespace { 
 
ABSL_CONST_INIT absl::Mutex help_attributes_guard(absl::kConstInit); 
ABSL_CONST_INIT std::string* match_substr 
    ABSL_GUARDED_BY(help_attributes_guard) = nullptr; 
ABSL_CONST_INIT HelpMode help_mode ABSL_GUARDED_BY(help_attributes_guard) = 
    HelpMode::kNone; 
ABSL_CONST_INIT HelpFormat help_format ABSL_GUARDED_BY(help_attributes_guard) = 
    HelpFormat::kHumanReadable; 
 
}  // namespace 
 
std::string GetFlagsHelpMatchSubstr() { 
  absl::MutexLock l(&help_attributes_guard); 
  if (match_substr == nullptr) return ""; 
  return *match_substr; 
} 
 
void SetFlagsHelpMatchSubstr(absl::string_view substr) { 
  absl::MutexLock l(&help_attributes_guard); 
  if (match_substr == nullptr) match_substr = new std::string; 
  match_substr->assign(substr.data(), substr.size()); 
} 
 
HelpMode GetFlagsHelpMode() { 
  absl::MutexLock l(&help_attributes_guard); 
  return help_mode; 
} 
 
void SetFlagsHelpMode(HelpMode mode) { 
  absl::MutexLock l(&help_attributes_guard); 
  help_mode = mode; 
} 
 
HelpFormat GetFlagsHelpFormat() { 
  absl::MutexLock l(&help_attributes_guard); 
  return help_format; 
} 
 
void SetFlagsHelpFormat(HelpFormat format) { 
  absl::MutexLock l(&help_attributes_guard); 
  help_format = format; 
} 
 
// Deduces usage flags from the input argument in a form --name=value or 
// --name. argument is already split into name and value before we call this 
// function. 
bool DeduceUsageFlags(absl::string_view name, absl::string_view value) { 
  if (absl::ConsumePrefix(&name, "help")) { 
    if (name == "") { 
      if (value.empty()) { 
        SetFlagsHelpMode(HelpMode::kImportant); 
      } else { 
        SetFlagsHelpMode(HelpMode::kMatch); 
        SetFlagsHelpMatchSubstr(value); 
      } 
      return true; 
    } 
 
    if (name == "match") { 
      SetFlagsHelpMode(HelpMode::kMatch); 
      SetFlagsHelpMatchSubstr(value); 
      return true; 
    } 
 
    if (name == "on") { 
      SetFlagsHelpMode(HelpMode::kMatch); 
      SetFlagsHelpMatchSubstr(absl::StrCat("/", value, ".")); 
      return true; 
    } 
 
    if (name == "full") { 
      SetFlagsHelpMode(HelpMode::kFull); 
      return true; 
    } 
 
    if (name == "short") { 
      SetFlagsHelpMode(HelpMode::kShort); 
      return true; 
    } 
 
    if (name == "package") { 
      SetFlagsHelpMode(HelpMode::kPackage); 
      return true; 
    } 
 
    return false; 
  }

  if (name == "version") { 
    SetFlagsHelpMode(HelpMode::kVersion); 
    return true; 
  }

  if (name == "only_check_args") { 
    SetFlagsHelpMode(HelpMode::kOnlyCheckArgs); 
    return true; 
  }

  return false; 
}

}  // namespace flags_internal
ABSL_NAMESPACE_END
}  // namespace absl