chromium/third_party/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 <algorithm>
#include <cstdlib>
#include <functional>
#include <iterator>
#include <map>
#include <ostream>
#include <string>
#include <utility>
#include <vector>

#include "absl/base/attributes.h"
#include "absl/base/config.h"
#include "absl/base/const_init.h"
#include "absl/base/thread_annotations.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/match.h"
#include "absl/strings/str_cat.h"
#include "absl/strings/str_split.h"
#include "absl/strings/string_view.h"
#include "absl/strings/strip.h"
#include "absl/synchronization/mutex.h"

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

namespace absl {
ABSL_NAMESPACE_BEGIN
namespace flags_internal {
namespace {

PerFlagFilter;

// Maximum length size in a human readable format.
constexpr size_t kHrfMaxLineLength = …;

// 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 { … };

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

class FlagHelpPrettyPrinter { … };

void FlagHelpHumanReadable(const CommandLineFlag& flag, std::ostream& out) { … }

// 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) { … }

void FlagsHelpImpl(std::ostream& out,
                   flags_internal::FlagKindFilter filename_filter_cb,
                   HelpFormat format, absl::string_view program_usage_message) { … }

}  // namespace

// --------------------------------------------------------------------
// Produces the help message describing specific flag.
void FlagHelp(std::ostream& out, const CommandLineFlag& flag,
              HelpFormat format) { … }

// --------------------------------------------------------------------
// 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) { … }

// --------------------------------------------------------------------
// Checks all the 'usage' command line flags to see if any have been set.
// If so, handles them appropriately.
HelpMode HandleUsageFlags(std::ostream& out,
                          absl::string_view program_usage_message) { … }

// --------------------------------------------------------------------
// 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) = …;
ABSL_CONST_INIT HelpMode help_mode ABSL_GUARDED_BY(help_attributes_guard) = …;
ABSL_CONST_INIT HelpFormat help_format ABSL_GUARDED_BY(help_attributes_guard) = …;

}  // namespace

std::string GetFlagsHelpMatchSubstr() { … }

void SetFlagsHelpMatchSubstr(absl::string_view substr) { … }

HelpMode GetFlagsHelpMode() { … }

void SetFlagsHelpMode(HelpMode mode) { … }

HelpFormat GetFlagsHelpFormat() { … }

void SetFlagsHelpFormat(HelpFormat 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) { … }

// --------------------------------------------------------------------

void MaybeExit(HelpMode mode) { … }

// --------------------------------------------------------------------

}  // namespace flags_internal
ABSL_NAMESPACE_END
}  // namespace absl