v8/third_party/inspector_protocol/crdtp/maybe.h
Andrey Kosyakov 3573d5e0fa Roll inspector_protocol library to inculude unified (de)serialization support
Note that changes in test expectation come from a more verbose
error diagnostics for expected errors around input parameter
validation.

Original change: https://chromium-review.googlesource.com/c/deps/inspector_protocol/+/2270757

Bug: chromium:1099809

Change-Id: I4fc2efc9c89d0af645dad937d719fa36e1d33489
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2277142
Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Andrey Kosyakov <caseq@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68657}
2020-07-02 14:08:19 +00:00

105 lines
2.4 KiB
C++

// Copyright 2019 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef V8_CRDTP_MAYBE_H_
#define V8_CRDTP_MAYBE_H_
#include <cassert>
#include <memory>
namespace v8_crdtp {
// =============================================================================
// detail::PtrMaybe, detail::ValueMaybe, templates for optional
// pointers / values which are used in ../lib/Forward_h.template.
// =============================================================================
namespace detail {
template <typename T>
class PtrMaybe {
public:
PtrMaybe() = default;
PtrMaybe(std::unique_ptr<T> value) : value_(std::move(value)) {}
PtrMaybe(PtrMaybe&& other) noexcept : value_(std::move(other.value_)) {}
void operator=(std::unique_ptr<T> value) { value_ = std::move(value); }
T* fromJust() const {
assert(value_);
return value_.get();
}
T* fromMaybe(T* default_value) const {
return value_ ? value_.get() : default_value;
}
bool isJust() const { return value_ != nullptr; }
std::unique_ptr<T> takeJust() {
assert(value_);
return std::move(value_);
}
private:
std::unique_ptr<T> value_;
};
template <typename T>
class ValueMaybe {
public:
ValueMaybe() : is_just_(false), value_() {}
ValueMaybe(T value) : is_just_(true), value_(std::move(value)) {}
ValueMaybe(ValueMaybe&& other) noexcept
: is_just_(other.is_just_), value_(std::move(other.value_)) {}
void operator=(T value) {
value_ = value;
is_just_ = true;
}
const T& fromJust() const {
assert(is_just_);
return value_;
}
const T& fromMaybe(const T& default_value) const {
return is_just_ ? value_ : default_value;
}
bool isJust() const { return is_just_; }
T takeJust() {
assert(is_just_);
is_just_ = false;
return std::move(value_);
}
private:
bool is_just_;
T value_;
};
template <typename T>
struct MaybeTypedef {
typedef PtrMaybe<T> type;
};
template <>
struct MaybeTypedef<bool> {
typedef ValueMaybe<bool> type;
};
template <>
struct MaybeTypedef<int> {
typedef ValueMaybe<int> type;
};
template <>
struct MaybeTypedef<double> {
typedef ValueMaybe<double> type;
};
template <>
struct MaybeTypedef<std::string> {
typedef ValueMaybe<std::string> type;
};
} // namespace detail
template <typename T>
using Maybe = typename detail::MaybeTypedef<T>::type;
} // namespace v8_crdtp
#endif // V8_CRDTP_MAYBE_H_