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// Copyright 2013 Google Inc. All Rights Reserved.
//
// 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
//
// http://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.
#ifndef CERT_TRANS_UTIL_STATUSOR_H_
#define CERT_TRANS_UTIL_STATUSOR_H_
#include <utility>
#include "glog/logging.h"
#include "util/status.h"
namespace util {
// A StatusOr holds a Status (in the case of an error), or a value T.
template <typename T>
class StatusOr {
public:
// Has status UNKNOWN.
inline StatusOr();
// Builds from a non-OK status. Crashes if an OK status is specified.
inline StatusOr(const ::util::Status& status); // NOLINT
// Builds from the specified value.
inline StatusOr(const T& value); // NOLINT
inline StatusOr(T&& value); // NOLINT
// Copy constructor.
inline StatusOr(const StatusOr& other);
// Move constructor.
inline StatusOr(StatusOr&& other);
// Conversion copy constructor, T must be copy constructible from U.
template <typename U>
inline StatusOr(const StatusOr<U>& other);
// Assignment operator.
inline const StatusOr& operator=(const StatusOr& other);
// Conversion assignment operator, T must be assignable from U
template <typename U>
inline const StatusOr& operator=(const StatusOr<U>& other);
// Accessors.
inline const ::util::Status& status() const {
return status_;
}
// Shorthand for status().ok().
inline bool ok() const {
return status_.ok();
}
// Returns value or crashes if ok() is false.
inline const T& ValueOrDie() const {
CHECK(ok()) << "Attempting to fetch value of non-OK StatusOr";
return value_;
}
inline T& ValueOrDie() {
CHECK(ok()) << "Attempting to fetch value of non-OK StatusOr";
return value_;
}
template <typename U>
friend class StatusOr;
private:
Status status_;
T value_;
};
// Implementation.
template <typename T>
inline StatusOr<T>::StatusOr() : status_(::util::error::UNKNOWN, "") {
}
template <typename T>
inline StatusOr<T>::StatusOr(const ::util::Status& status) : status_(status) {
CHECK(!status.ok()) << "Status::OK is not a valid argument to StatusOr";
}
template <typename T>
inline StatusOr<T>::StatusOr(const T& value) : value_(value) {
}
template <typename T>
inline StatusOr<T>::StatusOr(T&& value) : value_(std::move(value)) {
}
template <typename T>
inline StatusOr<T>::StatusOr(const StatusOr& other)
: status_(other.status_), value_(other.value_) {
}
template <typename T>
inline StatusOr<T>::StatusOr(StatusOr&& other)
: status_(other.status_), value_(std::move(other.value_)) {
}
template <typename T>
template <typename U>
inline StatusOr<T>::StatusOr(const StatusOr<U>& other)
: status_(other.status_), value_(other.value_) {
}
template <typename T>
inline const StatusOr<T>& StatusOr<T>::operator=(const StatusOr& other) {
status_ = other.status_;
if (status_.ok()) {
value_ = other.value_;
}
return *this;
}
template <typename T>
template <typename U>
inline const StatusOr<T>& StatusOr<T>::operator=(const StatusOr<U>& other) {
status_ = other.status_;
if (status_.ok()) {
value_ = other.value_;
}
return *this;
}
} // namespace util
#endif // CERT_TRANS_UTIL_STATUSOR_H_
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