chromium/third_party/abseil-cpp/absl/flags/usage_config.h

//
//  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 {
FlagKindFilter;
}  // 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 { … };

// 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 ABSL_INTERNAL_C_SYMBOL(AbslInternalReportFatalUsageError)(
    absl::string_view);

}  // extern "C"

#endif  // ABSL_FLAGS_USAGE_CONFIG_H_