chromium/third_party/abseil-cpp/absl/flags/reflection.cc

//
//  Copyright 2020 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/reflection.h"

#include <assert.h>

#include <atomic>
#include <string>

#include "absl/base/config.h"
#include "absl/base/no_destructor.h"
#include "absl/base/thread_annotations.h"
#include "absl/container/flat_hash_map.h"
#include "absl/flags/commandlineflag.h"
#include "absl/flags/internal/private_handle_accessor.h"
#include "absl/flags/internal/registry.h"
#include "absl/flags/usage_config.h"
#include "absl/strings/str_cat.h"
#include "absl/strings/string_view.h"
#include "absl/synchronization/mutex.h"

namespace absl {
ABSL_NAMESPACE_BEGIN
namespace flags_internal {

// --------------------------------------------------------------------
// FlagRegistry
//    A FlagRegistry singleton object holds all flag objects indexed by their
//    names so that if you know a flag's name, you can access or set it. If the
//    function is named FooLocked(), you must own the registry lock before
//    calling the function; otherwise, you should *not* hold the lock, and the
//    function will acquire it itself if needed.
// --------------------------------------------------------------------

class FlagRegistry { … };

namespace {

class FlagRegistryLock { … };

}  // namespace

CommandLineFlag* FlagRegistry::FindFlag(absl::string_view name) { … }

void FlagRegistry::RegisterFlag(CommandLineFlag& flag, const char* filename) { … }

FlagRegistry& FlagRegistry::GlobalRegistry() { … }

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

void ForEachFlag(std::function<void(CommandLineFlag&)> visitor) { … }

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

bool RegisterCommandLineFlag(CommandLineFlag& flag, const char* filename) { … }

void FinalizeRegistry() { … }

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

namespace {

// These are only used as constexpr global objects.
// They do not use a virtual destructor to simplify their implementation.
// They are not destroyed except at program exit, so leaks do not matter.
#if defined(__GNUC__) && !defined(__clang__)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wnon-virtual-dtor"
#endif
class RetiredFlagObj final : public CommandLineFlag { … };
#if defined(__GNUC__) && !defined(__clang__)
#pragma GCC diagnostic pop
#endif

}  // namespace

void Retire(const char* name, FlagFastTypeId type_id, char* buf) { … }

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

class FlagSaverImpl { … };

}  // namespace flags_internal

FlagSaver::FlagSaver() : … { … }

FlagSaver::~FlagSaver() { … }

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

CommandLineFlag* FindCommandLineFlag(absl::string_view name) { … }

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

absl::flat_hash_map<absl::string_view, absl::CommandLineFlag*> GetAllFlags() { … }

ABSL_NAMESPACE_END
}  // namespace absl