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+// 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.
+//
+// StatusOr<T> is the union of a Status object and a T
+// object. StatusOr models the concept of an object that is either a
+// usable value, or an error Status explaining why such a value is
+// not present. To this end, StatusOr<T> does not allow its Status
+// value to be absl::OkStatus().
+//
+// The primary use-case for StatusOr<T> is as the return value of a
+// function which may fail.
+//
+// Example usage of a StatusOr<T>:
+//
+// StatusOr<Foo> result = DoBigCalculationThatCouldFail();
+// if (result.ok()) {
+// result->DoSomethingCool();
+// } else {
+// LOG(ERROR) << result.status();
+// }
+//
+// Example that is guaranteed to crash if the result holds no value:
+//
+// StatusOr<Foo> result = DoBigCalculationThatCouldFail();
+// const Foo& foo = result.value();
+// foo.DoSomethingCool();
+//
+// Example usage of a StatusOr<std::unique_ptr<T>>:
+//
+// StatusOr<std::unique_ptr<Foo>> result = FooFactory::MakeNewFoo(arg);
+// if (!result.ok()) { // Don't omit .ok()
+// LOG(ERROR) << result.status();
+// } else if (*result == nullptr) {
+// LOG(ERROR) << "Unexpected null pointer";
+// } else {
+// (*result)->DoSomethingCool();
+// }
+//
+// Example factory implementation returning StatusOr<T>:
+//
+// StatusOr<Foo> FooFactory::MakeFoo(int arg) {
+// if (arg <= 0) {
+// return absl::Status(absl::StatusCode::kInvalidArgument,
+// "Arg must be positive");
+// }
+// return Foo(arg);
+// }
+//
+// NULL POINTERS
+//
+// Historically StatusOr<T*> treated null pointers specially. This is no longer
+// true -- a StatusOr<T*> can be constructed from a null pointer like any other
+// pointer value, and the result will be that ok() returns true and value()
+// returns null.
+
+#ifndef ABSL_STATUS_STATUSOR_H_
+#define ABSL_STATUS_STATUSOR_H_
+
+#include <exception>
+#include <initializer_list>
+#include <new>
+#include <string>
+#include <type_traits>
+#include <utility>
+
+#include "absl/base/attributes.h"
+#include "absl/meta/type_traits.h"
+#include "absl/status/internal/statusor_internal.h"
+#include "absl/status/status.h"
+#include "absl/types/variant.h"
+#include "absl/utility/utility.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+class BadStatusOrAccess : public std::exception {
+ public:
+ explicit BadStatusOrAccess(absl::Status status);
+ ~BadStatusOrAccess() override;
+ const char* what() const noexcept override;
+ const absl::Status& status() const;
+
+ private:
+ absl::Status status_;
+};
+
+// Returned StatusOr objects may not be ignored.
+template <typename T>
+class ABSL_MUST_USE_RESULT StatusOr;
+
+template <typename T>
+class StatusOr : private internal_statusor::StatusOrData<T>,
+ private internal_statusor::CopyCtorBase<T>,
+ private internal_statusor::MoveCtorBase<T>,
+ private internal_statusor::CopyAssignBase<T>,
+ private internal_statusor::MoveAssignBase<T> {
+ template <typename U>
+ friend class StatusOr;
+
+ typedef internal_statusor::StatusOrData<T> Base;
+
+ public:
+ typedef T value_type;
+
+ // Constructs a new StatusOr with Status::UNKNOWN status. This is marked
+ // 'explicit' to try to catch cases like 'return {};', where people think
+ // absl::StatusOr<std::vector<int>> will be initialized with an empty vector,
+ // instead of a Status::UNKNOWN status.
+ explicit StatusOr();
+
+ // StatusOr<T> is copy constructible if T is copy constructible.
+ StatusOr(const StatusOr&) = default;
+ // StatusOr<T> is copy assignable if T is copy constructible and copy
+ // assignable.
+ StatusOr& operator=(const StatusOr&) = default;
+
+ // StatusOr<T> is move constructible if T is move constructible.
+ StatusOr(StatusOr&&) = default;
+ // StatusOr<T> is moveAssignable if T is move constructible and move
+ // assignable.
+ StatusOr& operator=(StatusOr&&) = default;
+
+ // Converting constructors from StatusOr<U>, when T is constructible from U.
+ // To avoid ambiguity, they are disabled if T is also constructible from
+ // StatusOr<U>. Explicit iff the corresponding construction of T from U is
+ // explicit.
+ template <
+ typename U,
+ absl::enable_if_t<
+ absl::conjunction<
+ absl::negation<std::is_same<T, U>>,
+ std::is_constructible<T, const U&>,
+ std::is_convertible<const U&, T>,
+ absl::negation<
+ internal_statusor::IsConstructibleOrConvertibleFromStatusOr<
+ T, U>>>::value,
+ int> = 0>
+ StatusOr(const StatusOr<U>& other) // NOLINT
+ : Base(static_cast<const typename StatusOr<U>::Base&>(other)) {}
+ template <
+ typename U,
+ absl::enable_if_t<
+ absl::conjunction<
+ absl::negation<std::is_same<T, U>>,
+ std::is_constructible<T, const U&>,
+ absl::negation<std::is_convertible<const U&, T>>,
+ absl::negation<
+ internal_statusor::IsConstructibleOrConvertibleFromStatusOr<
+ T, U>>>::value,
+ int> = 0>
+ explicit StatusOr(const StatusOr<U>& other)
+ : Base(static_cast<const typename StatusOr<U>::Base&>(other)) {}
+
+ template <
+ typename U,
+ absl::enable_if_t<
+ absl::conjunction<
+ absl::negation<std::is_same<T, U>>, std::is_constructible<T, U&&>,
+ std::is_convertible<U&&, T>,
+ absl::negation<
+ internal_statusor::IsConstructibleOrConvertibleFromStatusOr<
+ T, U>>>::value,
+ int> = 0>
+ StatusOr(StatusOr<U>&& other) // NOLINT
+ : Base(static_cast<typename StatusOr<U>::Base&&>(other)) {}
+ template <
+ typename U,
+ absl::enable_if_t<
+ absl::conjunction<
+ absl::negation<std::is_same<T, U>>, std::is_constructible<T, U&&>,
+ absl::negation<std::is_convertible<U&&, T>>,
+ absl::negation<
+ internal_statusor::IsConstructibleOrConvertibleFromStatusOr<
+ T, U>>>::value,
+ int> = 0>
+ explicit StatusOr(StatusOr<U>&& other)
+ : Base(static_cast<typename StatusOr<U>::Base&&>(other)) {}
+
+ // Conversion copy/move assignment operator, T must be constructible and
+ // assignable from U. Only enable if T cannot be directly assigned from
+ // StatusOr<U>.
+ template <
+ typename U,
+ absl::enable_if_t<
+ absl::conjunction<
+ absl::negation<std::is_same<T, U>>,
+ std::is_constructible<T, const U&>,
+ std::is_assignable<T, const U&>,
+ absl::negation<
+ internal_statusor::
+ IsConstructibleOrConvertibleOrAssignableFromStatusOr<
+ T, U>>>::value,
+ int> = 0>
+ StatusOr& operator=(const StatusOr<U>& other) {
+ this->Assign(other);
+ return *this;
+ }
+ template <
+ typename U,
+ absl::enable_if_t<
+ absl::conjunction<
+ absl::negation<std::is_same<T, U>>, std::is_constructible<T, U&&>,
+ std::is_assignable<T, U&&>,
+ absl::negation<
+ internal_statusor::
+ IsConstructibleOrConvertibleOrAssignableFromStatusOr<
+ T, U>>>::value,
+ int> = 0>
+ StatusOr& operator=(StatusOr<U>&& other) {
+ this->Assign(std::move(other));
+ return *this;
+ }
+
+ // Constructs a new StatusOr with a non-ok status. After calling this
+ // constructor, this->ok() will be false and calls to value() will CHECK-fail.
+ // The constructor also takes any type `U` that is convertible to `Status`.
+ //
+ // NOTE: Not explicit - we want to use StatusOr<T> as a return
+ // value, so it is convenient and sensible to be able to do
+ // `return Status()` or `return ConvertibleToStatus()` when the return type
+ // is `StatusOr<T>`.
+ //
+ // REQUIRES: !Status(std::forward<U>(v)).ok(). This requirement is DCHECKed.
+ // In optimized builds, passing absl::OkStatus() here will have the effect
+ // of passing absl::StatusCode::kInternal as a fallback.
+ template <
+ typename U = absl::Status,
+ absl::enable_if_t<
+ absl::conjunction<
+ std::is_convertible<U&&, absl::Status>,
+ std::is_constructible<absl::Status, U&&>,
+ absl::negation<std::is_same<absl::decay_t<U>, absl::StatusOr<T>>>,
+ absl::negation<std::is_same<absl::decay_t<U>, T>>,
+ absl::negation<std::is_same<absl::decay_t<U>, absl::in_place_t>>,
+ absl::negation<internal_statusor::HasConversionOperatorToStatusOr<
+ T, U&&>>>::value,
+ int> = 0>
+ StatusOr(U&& v) : Base(std::forward<U>(v)) {}
+
+ template <
+ typename U = absl::Status,
+ absl::enable_if_t<
+ absl::conjunction<
+ absl::negation<std::is_convertible<U&&, absl::Status>>,
+ std::is_constructible<absl::Status, U&&>,
+ absl::negation<std::is_same<absl::decay_t<U>, absl::StatusOr<T>>>,
+ absl::negation<std::is_same<absl::decay_t<U>, T>>,
+ absl::negation<std::is_same<absl::decay_t<U>, absl::in_place_t>>,
+ absl::negation<internal_statusor::HasConversionOperatorToStatusOr<
+ T, U&&>>>::value,
+ int> = 0>
+ explicit StatusOr(U&& v) : Base(std::forward<U>(v)) {}
+
+ template <
+ typename U = absl::Status,
+ absl::enable_if_t<
+ absl::conjunction<
+ std::is_convertible<U&&, absl::Status>,
+ std::is_constructible<absl::Status, U&&>,
+ absl::negation<std::is_same<absl::decay_t<U>, absl::StatusOr<T>>>,
+ absl::negation<std::is_same<absl::decay_t<U>, T>>,
+ absl::negation<std::is_same<absl::decay_t<U>, absl::in_place_t>>,
+ absl::negation<internal_statusor::HasConversionOperatorToStatusOr<
+ T, U&&>>>::value,
+ int> = 0>
+ StatusOr& operator=(U&& v) {
+ this->AssignStatus(std::forward<U>(v));
+ return *this;
+ }
+
+ // Perfect-forwarding value assignment operator.
+ // If `*this` contains a `T` value before the call, the contained value is
+ // assigned from `std::forward<U>(v)`; Otherwise, it is directly-initialized
+ // from `std::forward<U>(v)`.
+ // This function does not participate in overload unless:
+ // 1. `std::is_constructible_v<T, U>` is true,
+ // 2. `std::is_assignable_v<T&, U>` is true.
+ // 3. `std::is_same_v<StatusOr<T>, std::remove_cvref_t<U>>` is false.
+ // 4. Assigning `U` to `T` is not ambiguous:
+ // If `U` is `StatusOr<V>` and `T` is constructible and assignable from
+ // both `StatusOr<V>` and `V`, the assignment is considered bug-prone and
+ // ambiguous thus will fail to compile. For example:
+ // StatusOr<bool> s1 = true; // s1.ok() && *s1 == true
+ // StatusOr<bool> s2 = false; // s2.ok() && *s2 == false
+ // s1 = s2; // ambiguous, `s1 = *s2` or `s1 = bool(s2)`?
+ template <
+ typename U = T,
+ typename = typename std::enable_if<absl::conjunction<
+ std::is_constructible<T, U&&>, std::is_assignable<T&, U&&>,
+ absl::disjunction<
+ std::is_same<absl::remove_cv_t<absl::remove_reference_t<U>>, T>,
+ absl::conjunction<
+ absl::negation<std::is_convertible<U&&, absl::Status>>,
+ absl::negation<internal_statusor::
+ HasConversionOperatorToStatusOr<T, U&&>>>>,
+ internal_statusor::IsForwardingAssignmentValid<T, U&&>>::value>::type>
+ StatusOr& operator=(U&& v) {
+ static_assert(
+ !absl::conjunction<
+ std::is_constructible<T, U&&>, std::is_assignable<T&, U&&>,
+ std::is_constructible<absl::Status, U&&>,
+ std::is_assignable<absl::Status&, U&&>,
+ absl::negation<std::is_same<
+ T, absl::remove_cv_t<absl::remove_reference_t<U>>>>>::value,
+ "U can assign to both T and Status, will result in semantic change");
+ static_assert(
+ !absl::conjunction<
+ std::is_constructible<T, U&&>, std::is_assignable<T&, U&&>,
+ internal_statusor::HasConversionOperatorToStatusOr<T, U&&>,
+ absl::negation<std::is_same<
+ T, absl::remove_cv_t<absl::remove_reference_t<U>>>>>::value,
+ "U can assign to T and convert to StatusOr<T>, will result in semantic "
+ "change");
+ this->Assign(std::forward<U>(v));
+ return *this;
+ }
+
+ // Constructs the inner value T in-place using the provided args, using the
+ // T(args...) constructor.
+ template <typename... Args>
+ explicit StatusOr(absl::in_place_t, Args&&... args);
+ template <typename U, typename... Args>
+ explicit StatusOr(absl::in_place_t, std::initializer_list<U> ilist,
+ Args&&... args);
+
+ // Constructs the inner value T in-place using the provided args, using the
+ // T(U) (direct-initialization) constructor. Only valid if T can be
+ // constructed from a U. Can accept move or copy constructors. Explicit if
+ // U is not convertible to T. To avoid ambiguity, this is disabled if U is
+ // a StatusOr<J>, where J is convertible to T.
+ template <
+ typename U = T,
+ absl::enable_if_t<
+ absl::conjunction<
+ internal_statusor::IsDirectInitializationValid<T, U&&>,
+ std::is_constructible<T, U&&>, std::is_convertible<U&&, T>,
+ absl::disjunction<
+ std::is_same<absl::remove_cv_t<absl::remove_reference_t<U>>,
+ T>,
+ absl::conjunction<
+ absl::negation<std::is_convertible<U&&, absl::Status>>,
+ absl::negation<
+ internal_statusor::HasConversionOperatorToStatusOr<
+ T, U&&>>>>>::value,
+ int> = 0>
+ StatusOr(U&& u) // NOLINT
+ : StatusOr(absl::in_place, std::forward<U>(u)) {
+ static_assert(
+ !absl::conjunction<
+ std::is_convertible<U&&, T>, std::is_convertible<U&&, absl::Status>,
+ absl::negation<std::is_same<
+ T, absl::remove_cv_t<absl::remove_reference_t<U>>>>>::value,
+ "U is convertible to both T and Status, will result in semantic "
+ "change");
+ static_assert(
+ !absl::conjunction<
+ std::is_convertible<U&&, T>,
+ internal_statusor::HasConversionOperatorToStatusOr<T, U&&>,
+ absl::negation<std::is_same<
+ T, absl::remove_cv_t<absl::remove_reference_t<U>>>>>::value,
+ "U can construct T and convert to StatusOr<T>, will result in semantic "
+ "change");
+ }
+
+ template <
+ typename U = T,
+ absl::enable_if_t<
+ absl::conjunction<
+ internal_statusor::IsDirectInitializationValid<T, U&&>,
+ absl::disjunction<
+ std::is_same<absl::remove_cv_t<absl::remove_reference_t<U>>,
+ T>,
+ absl::conjunction<
+ absl::negation<std::is_constructible<absl::Status, U&&>>,
+ absl::negation<
+ internal_statusor::HasConversionOperatorToStatusOr<
+ T, U&&>>>>,
+ std::is_constructible<T, U&&>,
+ absl::negation<std::is_convertible<U&&, T>>>::value,
+ int> = 0>
+ explicit StatusOr(U&& u) // NOLINT
+ : StatusOr(absl::in_place, std::forward<U>(u)) {
+ static_assert(
+ !absl::conjunction<
+ std::is_constructible<T, U&&>,
+ std::is_constructible<absl::Status, U&&>,
+ absl::negation<std::is_same<
+ T, absl::remove_cv_t<absl::remove_reference_t<U>>>>>::value,
+ "U can construct both T and Status, will result in semantic "
+ "change");
+ static_assert(
+ !absl::conjunction<
+ std::is_constructible<T, U&&>,
+ internal_statusor::HasConversionOperatorToStatusOr<T, U&&>,
+ absl::negation<std::is_same<
+ T, absl::remove_cv_t<absl::remove_reference_t<U>>>>>::value,
+ "U can construct T and convert to StatusOr<T>, will result in semantic "
+ "change");
+ }
+
+ // Returns this->status().ok()
+ ABSL_MUST_USE_RESULT bool ok() const { return this->status_.ok(); }
+
+ // Returns a reference to our status. If this contains a T, then
+ // returns absl::OkStatus().
+ const Status& status() const &;
+ Status status() &&;
+
+ // Returns a reference to the held value if `this->ok()`. Otherwise, throws
+ // `absl::BadStatusOrAccess` if exception is enabled, or `LOG(FATAL)` if
+ // exception is disabled.
+ // If you have already checked the status using `this->ok()`, you probably
+ // want to use `operator*()` or `operator->()` to access the value instead of
+ // `value`.
+ // Note: for value types that are cheap to copy, prefer simple code:
+ //
+ // T value = statusor.value();
+ //
+ // Otherwise, if the value type is expensive to copy, but can be left
+ // in the StatusOr, simply assign to a reference:
+ //
+ // T& value = statusor.value(); // or `const T&`
+ //
+ // Otherwise, if the value type supports an efficient move, it can be
+ // used as follows:
+ //
+ // T value = std::move(statusor).value();
+ //
+ // The `std::move` on statusor instead of on the whole expression enables
+ // warnings about possible uses of the statusor object after the move.
+ const T& value() const&;
+ T& value() &;
+ const T&& value() const&&;
+ T&& value() &&;
+
+ // Returns a reference to the current value.
+ //
+ // REQUIRES: this->ok() == true, otherwise the behavior is undefined.
+ //
+ // Use this->ok() to verify that there is a current value.
+ // Alternatively, see value() for a similar API that guarantees
+ // CHECK-failing if there is no current value.
+ const T& operator*() const&;
+ T& operator*() &;
+ const T&& operator*() const&&;
+ T&& operator*() &&;
+
+ // Returns a pointer to the current value.
+ //
+ // REQUIRES: this->ok() == true, otherwise the behavior is undefined.
+ //
+ // Use this->ok() to verify that there is a current value.
+ const T* operator->() const;
+ T* operator->();
+
+ // Returns the current value this->ok() == true. Otherwise constructs a value
+ // using `default_value`.
+ //
+ // Unlike `value`, this function returns by value, copying the current value
+ // if necessary. If the value type supports an efficient move, it can be used
+ // as follows:
+ //
+ // T value = std::move(statusor).value_or(def);
+ //
+ // Unlike with `value`, calling `std::move` on the result of `value_or` will
+ // still trigger a copy.
+ template <typename U>
+ T value_or(U&& default_value) const&;
+ template <typename U>
+ T value_or(U&& default_value) &&;
+
+ // Ignores any errors. This method does nothing except potentially suppress
+ // complaints from any tools that are checking that errors are not dropped on
+ // the floor.
+ void IgnoreError() const;
+
+ // Reconstructs the inner value T in-place using the provided args, using the
+ // T(args...) constructor. Returns reference to the reconstructed `T`.
+ template <typename... Args>
+ T& emplace(Args&&... args) {
+ if (ok()) {
+ this->Clear();
+ this->MakeValue(std::forward<Args>(args)...);
+ } else {
+ this->MakeValue(std::forward<Args>(args)...);
+ this->status_ = absl::OkStatus();
+ }
+ return this->data_;
+ }
+
+ template <
+ typename U, typename... Args,
+ absl::enable_if_t<
+ std::is_constructible<T, std::initializer_list<U>&, Args&&...>::value,
+ int> = 0>
+ T& emplace(std::initializer_list<U> ilist, Args&&... args) {
+ if (ok()) {
+ this->Clear();
+ this->MakeValue(ilist, std::forward<Args>(args)...);
+ } else {
+ this->MakeValue(ilist, std::forward<Args>(args)...);
+ this->status_ = absl::OkStatus();
+ }
+ return this->data_;
+ }
+
+ private:
+ using internal_statusor::StatusOrData<T>::Assign;
+ template <typename U>
+ void Assign(const absl::StatusOr<U>& other);
+ template <typename U>
+ void Assign(absl::StatusOr<U>&& other);
+};
+
+template <typename T>
+bool operator==(const StatusOr<T>& lhs, const StatusOr<T>& rhs) {
+ if (lhs.ok() && rhs.ok()) return *lhs == *rhs;
+ return lhs.status() == rhs.status();
+}
+
+template <typename T>
+bool operator!=(const StatusOr<T>& lhs, const StatusOr<T>& rhs) {
+ return !(lhs == rhs);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Implementation details for StatusOr<T>
+
+// TODO(sbenza): avoid the string here completely.
+template <typename T>
+StatusOr<T>::StatusOr() : Base(Status(absl::StatusCode::kUnknown, "")) {}
+
+template <typename T>
+template <typename U>
+inline void StatusOr<T>::Assign(const StatusOr<U>& other) {
+ if (other.ok()) {
+ this->Assign(*other);
+ } else {
+ this->AssignStatus(other.status());
+ }
+}
+
+template <typename T>
+template <typename U>
+inline void StatusOr<T>::Assign(StatusOr<U>&& other) {
+ if (other.ok()) {
+ this->Assign(*std::move(other));
+ } else {
+ this->AssignStatus(std::move(other).status());
+ }
+}
+template <typename T>
+template <typename... Args>
+StatusOr<T>::StatusOr(absl::in_place_t, Args&&... args)
+ : Base(absl::in_place, std::forward<Args>(args)...) {}
+
+template <typename T>
+template <typename U, typename... Args>
+StatusOr<T>::StatusOr(absl::in_place_t, std::initializer_list<U> ilist,
+ Args&&... args)
+ : Base(absl::in_place, ilist, std::forward<Args>(args)...) {}
+
+template <typename T>
+const Status& StatusOr<T>::status() const & { return this->status_; }
+template <typename T>
+Status StatusOr<T>::status() && {
+ return ok() ? OkStatus() : std::move(this->status_);
+}
+
+template <typename T>
+const T& StatusOr<T>::value() const& {
+ if (!this->ok()) internal_statusor::ThrowBadStatusOrAccess(this->status_);
+ return this->data_;
+}
+
+template <typename T>
+T& StatusOr<T>::value() & {
+ if (!this->ok()) internal_statusor::ThrowBadStatusOrAccess(this->status_);
+ return this->data_;
+}
+
+template <typename T>
+const T&& StatusOr<T>::value() const&& {
+ if (!this->ok()) {
+ internal_statusor::ThrowBadStatusOrAccess(std::move(this->status_));
+ }
+ return std::move(this->data_);
+}
+
+template <typename T>
+T&& StatusOr<T>::value() && {
+ if (!this->ok()) {
+ internal_statusor::ThrowBadStatusOrAccess(std::move(this->status_));
+ }
+ return std::move(this->data_);
+}
+
+template <typename T>
+const T& StatusOr<T>::operator*() const& {
+ this->EnsureOk();
+ return this->data_;
+}
+
+template <typename T>
+T& StatusOr<T>::operator*() & {
+ this->EnsureOk();
+ return this->data_;
+}
+
+template <typename T>
+const T&& StatusOr<T>::operator*() const&& {
+ this->EnsureOk();
+ return std::move(this->data_);
+}
+
+template <typename T>
+T&& StatusOr<T>::operator*() && {
+ this->EnsureOk();
+ return std::move(this->data_);
+}
+
+template <typename T>
+const T* StatusOr<T>::operator->() const {
+ this->EnsureOk();
+ return &this->data_;
+}
+
+template <typename T>
+T* StatusOr<T>::operator->() {
+ this->EnsureOk();
+ return &this->data_;
+}
+
+template <typename T>
+template <typename U>
+T StatusOr<T>::value_or(U&& default_value) const& {
+ if (ok()) {
+ return this->data_;
+ }
+ return std::forward<U>(default_value);
+}
+
+template <typename T>
+template <typename U>
+T StatusOr<T>::value_or(U&& default_value) && {
+ if (ok()) {
+ return std::move(this->data_);
+ }
+ return std::forward<U>(default_value);
+}
+
+template <typename T>
+void StatusOr<T>::IgnoreError() const {
+ // no-op
+}
+
+ABSL_NAMESPACE_END
+} // namespace absl
+
+#endif // ABSL_STATUS_STATUSOR_H_