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//
// 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
//
//
// 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/parse.h"
#include <stdlib.h>
#include <algorithm>
#include <cstdint>
#include <cstdlib>
#include <fstream>
#include <iostream>
#include <ostream>
#include <string>
#include <tuple>
#include <utility>
#include <vector>
#ifdef _WIN32
#include <windows.h>
#endif
#include "absl/algorithm/container.h"
#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/config.h"
#include "absl/flags/flag.h"
#include "absl/flags/internal/commandlineflag.h"
#include "absl/flags/internal/flag.h"
#include "absl/flags/internal/parse.h"
#include "absl/flags/internal/private_handle_accessor.h"
#include "absl/flags/internal/program_name.h"
#include "absl/flags/internal/usage.h"
#include "absl/flags/reflection.h"
#include "absl/flags/usage.h"
#include "absl/flags/usage_config.h"
#include "absl/strings/ascii.h"
#include "absl/strings/internal/damerau_levenshtein_distance.h"
#include "absl/strings/str_cat.h"
#include "absl/strings/str_join.h"
#include "absl/strings/string_view.h"
#include "absl/strings/strip.h"
#include "absl/synchronization/mutex.h"
// --------------------------------------------------------------------
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace flags_internal {
namespace {
ABSL_CONST_INIT absl::Mutex processing_checks_guard(absl::kConstInit);
ABSL_CONST_INIT bool flagfile_needs_processing
ABSL_GUARDED_BY(processing_checks_guard) = false;
ABSL_CONST_INIT bool fromenv_needs_processing
ABSL_GUARDED_BY(processing_checks_guard) = false;
ABSL_CONST_INIT bool tryfromenv_needs_processing
ABSL_GUARDED_BY(processing_checks_guard) = false;
ABSL_CONST_INIT absl::Mutex specified_flags_guard(absl::kConstInit);
ABSL_CONST_INIT std::vector<const CommandLineFlag*>* specified_flags
ABSL_GUARDED_BY(specified_flags_guard) = nullptr;
// Suggesting at most kMaxHints flags in case of misspellings.
ABSL_CONST_INIT const size_t kMaxHints = 100;
// Suggesting only flags which have a smaller distance than kMaxDistance.
ABSL_CONST_INIT const size_t kMaxDistance = 3;
struct SpecifiedFlagsCompare {
bool operator()(const CommandLineFlag* a, const CommandLineFlag* b) const {
return a->Name() < b->Name();
}
bool operator()(const CommandLineFlag* a, absl::string_view b) const {
return a->Name() < b;
}
bool operator()(absl::string_view a, const CommandLineFlag* b) const {
return a < b->Name();
}
};
} // namespace
} // namespace flags_internal
ABSL_NAMESPACE_END
} // namespace absl
// These flags influence how command line flags are parsed and are only intended
// to be set on the command line. Avoid reading or setting them from C++ code.
ABSL_FLAG(std::vector<std::string>, flagfile, {},
"comma-separated list of files to load flags from")
.OnUpdate([]() {
if (absl::GetFlag(FLAGS_flagfile).empty()) return;
absl::MutexLock l(&absl::flags_internal::processing_checks_guard);
// Setting this flag twice before it is handled most likely an internal
// error and should be reviewed by developers.
if (absl::flags_internal::flagfile_needs_processing) {
ABSL_INTERNAL_LOG(WARNING, "flagfile set twice before it is handled");
}
absl::flags_internal::flagfile_needs_processing = true;
});
ABSL_FLAG(std::vector<std::string>, fromenv, {},
"comma-separated list of flags to set from the environment"
" [use 'export FLAGS_flag1=value']")
.OnUpdate([]() {
if (absl::GetFlag(FLAGS_fromenv).empty()) return;
absl::MutexLock l(&absl::flags_internal::processing_checks_guard);
// Setting this flag twice before it is handled most likely an internal
// error and should be reviewed by developers.
if (absl::flags_internal::fromenv_needs_processing) {
ABSL_INTERNAL_LOG(WARNING, "fromenv set twice before it is handled.");
}
absl::flags_internal::fromenv_needs_processing = true;
});
ABSL_FLAG(std::vector<std::string>, tryfromenv, {},
"comma-separated list of flags to try to set from the environment if "
"present")
.OnUpdate([]() {
if (absl::GetFlag(FLAGS_tryfromenv).empty()) return;
absl::MutexLock l(&absl::flags_internal::processing_checks_guard);
// Setting this flag twice before it is handled most likely an internal
// error and should be reviewed by developers.
if (absl::flags_internal::tryfromenv_needs_processing) {
ABSL_INTERNAL_LOG(WARNING,
"tryfromenv set twice before it is handled.");
}
absl::flags_internal::tryfromenv_needs_processing = true;
});
// Rather than reading or setting --undefok from C++ code, please consider using
// ABSL_RETIRED_FLAG instead.
ABSL_FLAG(std::vector<std::string>, undefok, {},
"comma-separated list of flag names that it is okay to specify "
"on the command line even if the program does not define a flag "
"with that name");
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace flags_internal {
namespace {
class ArgsList {
public:
ArgsList() : next_arg_(0) {}
ArgsList(int argc, char* argv[]) : args_(argv, argv + argc), next_arg_(0) {}
explicit ArgsList(const std::vector<std::string>& args)
: args_(args), next_arg_(0) {}
// Returns success status: true if parsing successful, false otherwise.
bool ReadFromFlagfile(const std::string& flag_file_name);
size_t Size() const { return args_.size() - next_arg_; }
size_t FrontIndex() const { return next_arg_; }
absl::string_view Front() const { return args_[next_arg_]; }
void PopFront() { next_arg_++; }
private:
std::vector<std::string> args_;
size_t next_arg_;
};
bool ArgsList::ReadFromFlagfile(const std::string& flag_file_name) {
std::ifstream flag_file(flag_file_name);
if (!flag_file) {
flags_internal::ReportUsageError(
absl::StrCat("Can't open flagfile ", flag_file_name), true);
return false;
}
// This argument represents fake argv[0], which should be present in all arg
// lists.
args_.emplace_back("");
std::string line;
bool success = true;
while (std::getline(flag_file, line)) {
absl::string_view stripped = absl::StripLeadingAsciiWhitespace(line);
if (stripped.empty() || stripped[0] == '#') {
// Comment or empty line; just ignore.
continue;
}
if (stripped[0] == '-') {
if (stripped == "--") {
flags_internal::ReportUsageError(
"Flagfile can't contain position arguments or --", true);
success = false;
break;
}
args_.emplace_back(stripped);
continue;
}
flags_internal::ReportUsageError(
absl::StrCat("Unexpected line in the flagfile ", flag_file_name, ": ",
line),
true);
success = false;
}
return success;
}
// --------------------------------------------------------------------
// Reads the environment variable with name `name` and stores results in
// `value`. If variable is not present in environment returns false, otherwise
// returns true.
bool GetEnvVar(const char* var_name, std::string& var_value) {
#ifdef _WIN32
char buf[1024];
auto get_res = GetEnvironmentVariableA(var_name, buf, sizeof(buf));
if (get_res >= sizeof(buf)) {
return false;
}
if (get_res == 0) {
return false;
}
var_value = std::string(buf, get_res);
#else
const char* val = ::getenv(var_name);
if (val == nullptr) {
return false;
}
var_value = val;
#endif
return true;
}
// --------------------------------------------------------------------
// Returns:
// Flag name or empty if arg= --
// Flag value after = in --flag=value (empty if --foo)
// "Is empty value" status. True if arg= --foo=, false otherwise. This is
// required to separate --foo from --foo=.
// For example:
// arg return values
// "--foo=bar" -> {"foo", "bar", false}.
// "--foo" -> {"foo", "", false}.
// "--foo=" -> {"foo", "", true}.
std::tuple<absl::string_view, absl::string_view, bool> SplitNameAndValue(
absl::string_view arg) {
// Allow -foo and --foo
absl::ConsumePrefix(&arg, "-");
if (arg.empty()) {
return std::make_tuple("", "", false);
}
auto equal_sign_pos = arg.find('=');
absl::string_view flag_name = arg.substr(0, equal_sign_pos);
absl::string_view value;
bool is_empty_value = false;
if (equal_sign_pos != absl::string_view::npos) {
value = arg.substr(equal_sign_pos + 1);
is_empty_value = value.empty();
}
return std::make_tuple(flag_name, value, is_empty_value);
}
// --------------------------------------------------------------------
// Returns:
// found flag or nullptr
// is negative in case of --nofoo
std::tuple<CommandLineFlag*, bool> LocateFlag(absl::string_view flag_name) {
CommandLineFlag* flag = absl::FindCommandLineFlag(flag_name);
bool is_negative = false;
if (!flag && absl::ConsumePrefix(&flag_name, "no")) {
flag = absl::FindCommandLineFlag(flag_name);
is_negative = true;
}
return std::make_tuple(flag, is_negative);
}
// --------------------------------------------------------------------
// Verify that default values of typed flags must be convertible to string and
// back.
void CheckDefaultValuesParsingRoundtrip() {
#ifndef NDEBUG
flags_internal::ForEachFlag([&](CommandLineFlag& flag) {
if (flag.IsRetired()) return;
#define ABSL_FLAGS_INTERNAL_IGNORE_TYPE(T, _) \
if (flag.IsOfType<T>()) return;
ABSL_FLAGS_INTERNAL_SUPPORTED_TYPES(ABSL_FLAGS_INTERNAL_IGNORE_TYPE)
#undef ABSL_FLAGS_INTERNAL_IGNORE_TYPE
flags_internal::PrivateHandleAccessor::CheckDefaultValueParsingRoundtrip(
flag);
});
#endif
}
// --------------------------------------------------------------------
// Returns success status, which is true if we successfully read all flag files,
// in which case new ArgLists are appended to the input_args in a reverse order
// of file names in the input flagfiles list. This order ensures that flags from
// the first flagfile in the input list are processed before the second flagfile
// etc.
bool ReadFlagfiles(const std::vector<std::string>& flagfiles,
std::vector<ArgsList>& input_args) {
bool success = true;
for (auto it = flagfiles.rbegin(); it != flagfiles.rend(); ++it) {
ArgsList al;
if (al.ReadFromFlagfile(*it)) {
input_args.push_back(al);
} else {
success = false;
}
}
return success;
}
// Returns success status, which is true if were able to locate all environment
// variables correctly or if fail_on_absent_in_env is false. The environment
// variable names are expected to be of the form `FLAGS_<flag_name>`, where
// `flag_name` is a string from the input flag_names list. If successful we
// append a single ArgList at the end of the input_args.
bool ReadFlagsFromEnv(const std::vector<std::string>& flag_names,
std::vector<ArgsList>& input_args,
bool fail_on_absent_in_env) {
bool success = true;
std::vector<std::string> args;
// This argument represents fake argv[0], which should be present in all arg
// lists.
args.emplace_back("");
for (const auto& flag_name : flag_names) {
// Avoid infinite recursion.
if (flag_name == "fromenv" || flag_name == "tryfromenv") {
flags_internal::ReportUsageError(
absl::StrCat("Infinite recursion on flag ", flag_name), true);
success = false;
continue;
}
const std::string envname = absl::StrCat("FLAGS_", flag_name);
std::string envval;
if (!GetEnvVar(envname.c_str(), envval)) {
if (fail_on_absent_in_env) {
flags_internal::ReportUsageError(
absl::StrCat(envname, " not found in environment"), true);
success = false;
}
continue;
}
args.push_back(absl::StrCat("--", flag_name, "=", envval));
}
if (success) {
input_args.emplace_back(args);
}
return success;
}
// --------------------------------------------------------------------
// Returns success status, which is true if were able to handle all generator
// flags (flagfile, fromenv, tryfromemv) successfully.
bool HandleGeneratorFlags(std::vector<ArgsList>& input_args,
std::vector<std::string>& flagfile_value) {
bool success = true;
absl::MutexLock l(&flags_internal::processing_checks_guard);
// flagfile could have been set either on a command line or
// programmatically before invoking ParseCommandLine. Note that we do not
// actually process arguments specified in the flagfile, but instead
// create a secondary arguments list to be processed along with the rest
// of the command line arguments. Since we always the process most recently
// created list of arguments first, this will result in flagfile argument
// being processed before any other argument in the command line. If
// FLAGS_flagfile contains more than one file name we create multiple new
// levels of arguments in a reverse order of file names. Thus we always
// process arguments from first file before arguments containing in a
// second file, etc. If flagfile contains another
// --flagfile inside of it, it will produce new level of arguments and
// processed before the rest of the flagfile. We are also collecting all
// flagfiles set on original command line. Unlike the rest of the flags,
// this flag can be set multiple times and is expected to be handled
// multiple times. We are collecting them all into a single list and set
// the value of FLAGS_flagfile to that value at the end of the parsing.
if (flags_internal::flagfile_needs_processing) {
auto flagfiles = absl::GetFlag(FLAGS_flagfile);
if (input_args.size() == 1) {
flagfile_value.insert(flagfile_value.end(), flagfiles.begin(),
flagfiles.end());
}
success &= ReadFlagfiles(flagfiles, input_args);
flags_internal::flagfile_needs_processing = false;
}
// Similar to flagfile fromenv/tryfromemv can be set both
// programmatically and at runtime on a command line. Unlike flagfile these
// can't be recursive.
if (flags_internal::fromenv_needs_processing) {
auto flags_list = absl::GetFlag(FLAGS_fromenv);
success &= ReadFlagsFromEnv(flags_list, input_args, true);
flags_internal::fromenv_needs_processing = false;
}
if (flags_internal::tryfromenv_needs_processing) {
auto flags_list = absl::GetFlag(FLAGS_tryfromenv);
success &= ReadFlagsFromEnv(flags_list, input_args, false);
flags_internal::tryfromenv_needs_processing = false;
}
return success;
}
// --------------------------------------------------------------------
void ResetGeneratorFlags(const std::vector<std::string>& flagfile_value) {
// Setting flagfile to the value which collates all the values set on a
// command line and programmatically. So if command line looked like
// --flagfile=f1 --flagfile=f2 the final value of the FLAGS_flagfile flag is
// going to be {"f1", "f2"}
if (!flagfile_value.empty()) {
absl::SetFlag(&FLAGS_flagfile, flagfile_value);
absl::MutexLock l(&flags_internal::processing_checks_guard);
flags_internal::flagfile_needs_processing = false;
}
// fromenv/tryfromenv are set to <undefined> value.
if (!absl::GetFlag(FLAGS_fromenv).empty()) {
absl::SetFlag(&FLAGS_fromenv, {});
}
if (!absl::GetFlag(FLAGS_tryfromenv).empty()) {
absl::SetFlag(&FLAGS_tryfromenv, {});
}
absl::MutexLock l(&flags_internal::processing_checks_guard);
flags_internal::fromenv_needs_processing = false;
flags_internal::tryfromenv_needs_processing = false;
}
// --------------------------------------------------------------------
// Returns:
// success status
// deduced value
// We are also mutating curr_list in case if we need to get a hold of next
// argument in the input.
std::tuple<bool, absl::string_view> DeduceFlagValue(const CommandLineFlag& flag,
absl::string_view value,
bool is_negative,
bool is_empty_value,
ArgsList* curr_list) {
// Value is either an argument suffix after `=` in "--foo=<value>"
// or separate argument in case of "--foo" "<value>".
// boolean flags have these forms:
// --foo
// --nofoo
// --foo=true
// --foo=false
// --nofoo=<value> is not supported
// --foo <value> is not supported
// non boolean flags have these forms:
// --foo=<value>
// --foo <value>
// --nofoo is not supported
if (flag.IsOfType<bool>()) {
if (value.empty()) {
if (is_empty_value) {
// "--bool_flag=" case
flags_internal::ReportUsageError(
absl::StrCat(
"Missing the value after assignment for the boolean flag '",
flag.Name(), "'"),
true);
return std::make_tuple(false, "");
}
// "--bool_flag" case
value = is_negative ? "0" : "1";
} else if (is_negative) {
// "--nobool_flag=Y" case
flags_internal::ReportUsageError(
absl::StrCat("Negative form with assignment is not valid for the "
"boolean flag '",
flag.Name(), "'"),
true);
return std::make_tuple(false, "");
}
} else if (is_negative) {
// "--noint_flag=1" case
flags_internal::ReportUsageError(
absl::StrCat("Negative form is not valid for the flag '", flag.Name(),
"'"),
true);
return std::make_tuple(false, "");
} else if (value.empty() && (!is_empty_value)) {
if (curr_list->Size() == 1) {
// "--int_flag" case
flags_internal::ReportUsageError(
absl::StrCat("Missing the value for the flag '", flag.Name(), "'"),
true);
return std::make_tuple(false, "");
}
// "--int_flag" "10" case
curr_list->PopFront();
value = curr_list->Front();
// Heuristic to detect the case where someone treats a string arg
// like a bool or just forgets to pass a value:
// --my_string_var --foo=bar
// We look for a flag of string type, whose value begins with a
// dash and corresponds to known flag or standalone --.
if (!value.empty() && value[0] == '-' && flag.IsOfType<std::string>()) {
auto maybe_flag_name = std::get<0>(SplitNameAndValue(value.substr(1)));
if (maybe_flag_name.empty() ||
std::get<0>(LocateFlag(maybe_flag_name)) != nullptr) {
// "--string_flag" "--known_flag" case
ABSL_INTERNAL_LOG(
WARNING,
absl::StrCat("Did you really mean to set flag '", flag.Name(),
"' to the value '", value, "'?"));
}
}
}
return std::make_tuple(true, value);
}
// --------------------------------------------------------------------
bool CanIgnoreUndefinedFlag(absl::string_view flag_name) {
auto undefok = absl::GetFlag(FLAGS_undefok);
if (std::find(undefok.begin(), undefok.end(), flag_name) != undefok.end()) {
return true;
}
if (absl::ConsumePrefix(&flag_name, "no") &&
std::find(undefok.begin(), undefok.end(), flag_name) != undefok.end()) {
return true;
}
return false;
}
// --------------------------------------------------------------------
void ReportUnrecognizedFlags(
const std::vector<UnrecognizedFlag>& unrecognized_flags,
bool report_as_fatal_error) {
for (const auto& unrecognized : unrecognized_flags) {
// Verify if flag_name has the "no" already removed
std::vector<std::string> misspelling_hints;
if (unrecognized.source == UnrecognizedFlag::kFromArgv) {
misspelling_hints =
flags_internal::GetMisspellingHints(unrecognized.flag_name);
}
if (misspelling_hints.empty()) {
flags_internal::ReportUsageError(
absl::StrCat("Unknown command line flag '", unrecognized.flag_name,
"'"),
report_as_fatal_error);
} else {
flags_internal::ReportUsageError(
absl::StrCat("Unknown command line flag '", unrecognized.flag_name,
"'. Did you mean: ",
absl::StrJoin(misspelling_hints, ", "), " ?"),
report_as_fatal_error);
}
}
}
} // namespace
// --------------------------------------------------------------------
bool WasPresentOnCommandLine(absl::string_view flag_name) {
absl::ReaderMutexLock l(&specified_flags_guard);
ABSL_INTERNAL_CHECK(specified_flags != nullptr,
"ParseCommandLine is not invoked yet");
return std::binary_search(specified_flags->begin(), specified_flags->end(),
flag_name, SpecifiedFlagsCompare{});
}
// --------------------------------------------------------------------
struct BestHints {
explicit BestHints(uint8_t _max) : best_distance(_max + 1) {}
bool AddHint(absl::string_view hint, uint8_t distance) {
if (hints.size() >= kMaxHints) return false;
if (distance == best_distance) {
hints.emplace_back(hint);
}
if (distance < best_distance) {
best_distance = distance;
hints = std::vector<std::string>{std::string(hint)};
}
return true;
}
uint8_t best_distance;
std::vector<std::string> hints;
};
// Return the list of flags with the smallest Damerau-Levenshtein distance to
// the given flag.
std::vector<std::string> GetMisspellingHints(const absl::string_view flag) {
const size_t maxCutoff = std::min(flag.size() / 2 + 1, kMaxDistance);
auto undefok = absl::GetFlag(FLAGS_undefok);
BestHints best_hints(static_cast<uint8_t>(maxCutoff));
flags_internal::ForEachFlag([&](const CommandLineFlag& f) {
if (best_hints.hints.size() >= kMaxHints) return;
uint8_t distance = strings_internal::CappedDamerauLevenshteinDistance(
flag, f.Name(), best_hints.best_distance);
best_hints.AddHint(f.Name(), distance);
// For boolean flags, also calculate distance to the negated form.
if (f.IsOfType<bool>()) {
const std::string negated_flag = absl::StrCat("no", f.Name());
distance = strings_internal::CappedDamerauLevenshteinDistance(
flag, negated_flag, best_hints.best_distance);
best_hints.AddHint(negated_flag, distance);
}
});
// Finally calculate distance to flags in "undefok".
absl::c_for_each(undefok, [&](const absl::string_view f) {
if (best_hints.hints.size() >= kMaxHints) return;
uint8_t distance = strings_internal::CappedDamerauLevenshteinDistance(
flag, f, best_hints.best_distance);
best_hints.AddHint(absl::StrCat(f, " (undefok)"), distance);
});
return best_hints.hints;
}
// --------------------------------------------------------------------
std::vector<char*> ParseCommandLineImpl(int argc, char* argv[],
UsageFlagsAction usage_flag_action,
OnUndefinedFlag undef_flag_action,
std::ostream& error_help_output) {
std::vector<char*> positional_args;
std::vector<UnrecognizedFlag> unrecognized_flags;
auto help_mode = flags_internal::ParseAbseilFlagsOnlyImpl(
argc, argv, positional_args, unrecognized_flags, usage_flag_action);
if (undef_flag_action != OnUndefinedFlag::kIgnoreUndefined) {
flags_internal::ReportUnrecognizedFlags(
unrecognized_flags,
(undef_flag_action == OnUndefinedFlag::kAbortIfUndefined));
if (undef_flag_action == OnUndefinedFlag::kAbortIfUndefined) {
if (!unrecognized_flags.empty()) {
flags_internal::HandleUsageFlags(error_help_output,
ProgramUsageMessage()); std::exit(1);
}
}
}
flags_internal::MaybeExit(help_mode);
return positional_args;
}
// --------------------------------------------------------------------
// This function handles all Abseil Flags and built-in usage flags and, if any
// help mode was handled, it returns that help mode. The caller of this function
// can decide to exit based on the returned help mode.
// The caller may decide to handle unrecognized positional arguments and
// unrecognized flags first before exiting.
//
// Returns:
// * HelpMode::kFull if parsing errors were detected in recognized arguments
// * The HelpMode that was handled in case when `usage_flag_action` is
// UsageFlagsAction::kHandleUsage and a usage flag was specified on the
// commandline
// * Otherwise it returns HelpMode::kNone
HelpMode ParseAbseilFlagsOnlyImpl(
int argc, char* argv[], std::vector<char*>& positional_args,
std::vector<UnrecognizedFlag>& unrecognized_flags,
UsageFlagsAction usage_flag_action) {
ABSL_INTERNAL_CHECK(argc > 0, "Missing argv[0]");
using flags_internal::ArgsList;
using flags_internal::specified_flags;
std::vector<std::string> flagfile_value;
std::vector<ArgsList> input_args;
// Once parsing has started we will not allow more flag registrations.
flags_internal::FinalizeRegistry();
// This routine does not return anything since we abort on failure.
flags_internal::CheckDefaultValuesParsingRoundtrip();
input_args.push_back(ArgsList(argc, argv));
// Set program invocation name if it is not set before.
if (flags_internal::ProgramInvocationName() == "UNKNOWN") {
flags_internal::SetProgramInvocationName(argv[0]);
}
positional_args.push_back(argv[0]);
absl::MutexLock l(&flags_internal::specified_flags_guard);
if (specified_flags == nullptr) {
specified_flags = new std::vector<const CommandLineFlag*>;
} else {
specified_flags->clear();
}
// Iterate through the list of the input arguments. First level are
// arguments originated from argc/argv. Following levels are arguments
// originated from recursive parsing of flagfile(s).
bool success = true;
while (!input_args.empty()) {
// First we process the built-in generator flags.
success &= flags_internal::HandleGeneratorFlags(input_args, flagfile_value);
// Select top-most (most recent) arguments list. If it is empty drop it
// and re-try.
ArgsList& curr_list = input_args.back();
// Every ArgsList starts with real or fake program name, so we can always
// start by skipping it.
curr_list.PopFront();
if (curr_list.Size() == 0) {
input_args.pop_back();
continue;
}
// Handle the next argument in the current list. If the stack of argument
// lists contains only one element - we are processing an argument from
// the original argv.
absl::string_view arg(curr_list.Front());
bool arg_from_argv = input_args.size() == 1;
// If argument does not start with '-' or is just "-" - this is
// positional argument.
if (!absl::ConsumePrefix(&arg, "-") || arg.empty()) {
ABSL_INTERNAL_CHECK(arg_from_argv,
"Flagfile cannot contain positional argument");
positional_args.push_back(argv[curr_list.FrontIndex()]);
continue;
}
// Split the current argument on '=' to deduce the argument flag name and
// value. If flag name is empty it means we've got an "--" argument. Value
// can be empty either if there were no '=' in argument string at all or
// an argument looked like "--foo=". In a latter case is_empty_value is
// true.
absl::string_view flag_name;
absl::string_view value;
bool is_empty_value = false;
std::tie(flag_name, value, is_empty_value) =
flags_internal::SplitNameAndValue(arg);
// Standalone "--" argument indicates that the rest of the arguments are
// positional. We do not support positional arguments in flagfiles.
if (flag_name.empty()) {
ABSL_INTERNAL_CHECK(arg_from_argv,
"Flagfile cannot contain positional argument");
curr_list.PopFront();
break;
}
// Locate the flag based on flag name. Handle both --foo and --nofoo.
CommandLineFlag* flag = nullptr;
bool is_negative = false;
std::tie(flag, is_negative) = flags_internal::LocateFlag(flag_name);
if (flag == nullptr) {
// Usage flags are not modeled as Abseil flags. Locate them separately.
if (flags_internal::DeduceUsageFlags(flag_name, value)) {
continue;
}
unrecognized_flags.emplace_back(arg_from_argv
? UnrecognizedFlag::kFromArgv
: UnrecognizedFlag::kFromFlagfile,
flag_name);
continue;
}
// Deduce flag's value (from this or next argument).
bool value_success = true;
std::tie(value_success, value) = flags_internal::DeduceFlagValue(
*flag, value, is_negative, is_empty_value, &curr_list);
success &= value_success;
// Set the located flag to a new value, unless it is retired. Setting
// retired flag fails, but we ignoring it here while also reporting access
// to retired flag.
std::string error;
if (!flags_internal::PrivateHandleAccessor::ParseFrom(
*flag, value, flags_internal::SET_FLAGS_VALUE,
flags_internal::kCommandLine, error)) {
if (flag->IsRetired()) continue;
flags_internal::ReportUsageError(error, true);
success = false;
} else {
specified_flags->push_back(flag);
}
}
flags_internal::ResetGeneratorFlags(flagfile_value);
// All the remaining arguments are positional.
if (!input_args.empty()) {
for (size_t arg_index = input_args.back().FrontIndex();
arg_index < static_cast<size_t>(argc); ++arg_index) {
positional_args.push_back(argv[arg_index]);
}
}
// Trim and sort the vector.
specified_flags->shrink_to_fit();
std::sort(specified_flags->begin(), specified_flags->end(),
flags_internal::SpecifiedFlagsCompare{});
// Filter out unrecognized flags, which are ok to ignore.
std::vector<UnrecognizedFlag> filtered;
filtered.reserve(unrecognized_flags.size());
for (const auto& unrecognized : unrecognized_flags) {
if (flags_internal::CanIgnoreUndefinedFlag(unrecognized.flag_name))
continue;
filtered.push_back(unrecognized);
}
std::swap(unrecognized_flags, filtered);
if (!success) {
#if ABSL_FLAGS_STRIP_NAMES
flags_internal::ReportUsageError(
"NOTE: command line flags are disabled in this build", true);
#else
flags_internal::HandleUsageFlags(std::cerr, ProgramUsageMessage());
#endif
return HelpMode::kFull; // We just need to make sure the exit with
// code 1.
}
return usage_flag_action == UsageFlagsAction::kHandleUsage
? flags_internal::HandleUsageFlags(std::cout,
ProgramUsageMessage())
: HelpMode::kNone;
}
} // namespace flags_internal
void ParseAbseilFlagsOnly(int argc, char* argv[],
std::vector<char*>& positional_args,
std::vector<UnrecognizedFlag>& unrecognized_flags) {
auto help_mode = flags_internal::ParseAbseilFlagsOnlyImpl(
argc, argv, positional_args, unrecognized_flags,
flags_internal::UsageFlagsAction::kHandleUsage);
flags_internal::MaybeExit(help_mode);
}
// --------------------------------------------------------------------
void ReportUnrecognizedFlags(
const std::vector<UnrecognizedFlag>& unrecognized_flags) {
flags_internal::ReportUnrecognizedFlags(unrecognized_flags, true);
}
// --------------------------------------------------------------------
std::vector<char*> ParseCommandLine(int argc, char* argv[]) {
return flags_internal::ParseCommandLineImpl(
argc, argv, flags_internal::UsageFlagsAction::kHandleUsage,
flags_internal::OnUndefinedFlag::kAbortIfUndefined);
}
ABSL_NAMESPACE_END
} // namespace absl