chromium/media/base/status.h

// Copyright 2020 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef MEDIA_BASE_STATUS_H_
#define MEDIA_BASE_STATUS_H_

#include <memory>
#include <string>
#include <string_view>
#include <type_traits>
#include <utility>
#include <vector>

#include "base/functional/bind.h"
#include "base/location.h"
#include "base/values.h"
#include "media/base/crc_16.h"
#include "media/base/media_export.h"
#include "media/base/media_serializers_base.h"

// Mojo namespaces for serialization friend declarations.
namespace mojo {
template <typename T, typename U>
struct StructTraits;
}  // namespace mojo

#define POST_STATUS_AND_RETURN_ON_FAILURE(eval_to_status, cb, ret) …

namespace media {

// See media/base/status.md for details and instructions for
// using TypedStatus<T>.

// This is the type that enum classes used for specializing |TypedStatus| must
// extend from.
StatusCodeType;

// This is the type that TypedStatusTraits::Group should be.
StatusGroupType;

// This is the type that a status will get serialized into for UKM purposes.
UKMPackedType;

namespace internal {

template <typename T>
struct SecondArgType { … };

SecondArgType<R (A1, A2)>;

UKMPackHelper;

struct MEDIA_EXPORT StatusData { … };

#define NAME_DETECTOR …

NAME_DETECTOR(HasOkCode, kOk);
NAME_DETECTOR(HasPackExtraData, PackExtraData);
NAME_DETECTOR(HasSetDefaultOk, OkEnumValue);

#undef NAME_DETECTOR

// Helper class to allow traits with no default enum.
template <typename T>
struct StatusTraitsHelper { … };

// Implicitly converts to an ok value for any implementation of TypedStatus.
struct OkStatusImplicitConstructionHelper { … };

// For gtest, so it can print this.  Otherwise, it tries to convert to an
// integer for printing.  That'd be okay, except our implicit cast matches the
// attempt to convert to long long, and tries to get `T::kOk` for `long long`.
MEDIA_EXPORT std::ostream& operator<<(
    std::ostream& stream,
    const OkStatusImplicitConstructionHelper&);

}  // namespace internal

// Constant names for serialized TypedStatus<T>.
struct MEDIA_EXPORT StatusConstants { … };

// See media/base/status.md for details and instructions for using TypedStatus.
template <typename T>
class MEDIA_EXPORT TypedStatus { … };

template <typename T>
inline bool operator==(typename T::Codes code, const TypedStatus<T>& status) { … }

template <typename T>
inline bool operator!=(typename T::Codes code, const TypedStatus<T>& status) { … }

// Convenience function to return |kOk|.
// OK won't have a message, trace, or data associated with them, and DCHECK
// if they are added.
MEDIA_EXPORT internal::OkStatusImplicitConstructionHelper OkStatus();

}  // namespace media

#endif  // MEDIA_BASE_STATUS_H_