#include <folly/Launder.h>
#include <folly/Portability.h>
+#include <folly/Traits.h>
#include <folly/Utility.h>
namespace folly {
!std::is_abstract<Value>::value,
"Optional may not be used with abstract types");
- Optional() noexcept {}
+ FOLLY_CPP14_CONSTEXPR Optional() noexcept {}
Optional(const Optional& src) noexcept(
std::is_nothrow_copy_constructible<Value>::value) {
}
}
- /* implicit */ Optional(const None&) noexcept {}
+ FOLLY_CPP14_CONSTEXPR /* implicit */ Optional(const None&) noexcept {}
- /* implicit */ Optional(Value&& newValue) noexcept(
+ FOLLY_CPP14_CONSTEXPR /* implicit */ Optional(Value&& newValue) noexcept(
std::is_nothrow_move_constructible<Value>::value) {
storage_.construct(std::move(newValue));
}
- /* implicit */ Optional(const Value& newValue) noexcept(
+ FOLLY_CPP14_CONSTEXPR /* implicit */ Optional(const Value& newValue) noexcept(
std::is_nothrow_copy_constructible<Value>::value) {
storage_.construct(newValue);
}
template <typename... Args>
- explicit Optional(in_place_t, Args&&... args) noexcept(
+ FOLLY_CPP14_CONSTEXPR explicit Optional(in_place_t, Args&&... args) noexcept(
std::is_nothrow_constructible<Value, Args...>::value) {
storage_.construct(std::forward<Args>(args)...);
}
}
template <class... Args>
- void emplace(Args&&... args) {
+ Value& emplace(Args&&... args) {
clear();
- storage_.construct(std::forward<Args>(args)...);
+ return storage_.construct(std::forward<Args>(args)...);
+ }
+
+ template <class U, class... Args>
+ typename std::enable_if<
+ std::is_constructible<Value, std::initializer_list<U>&, Args&&...>::value,
+ Value&>::type
+ emplace(std::initializer_list<U> ilist, Args&&... args) {
+ clear();
+ return storage_.construct(ilist, std::forward<Args>(args)...);
}
- void clear() {
+ void reset() noexcept {
storage_.clear();
}
- const Value& value() const & {
+ void clear() noexcept {
+ reset();
+ }
+
+ void swap(Optional& that) noexcept(IsNothrowSwappable<Value>::value) {
+ if (hasValue() && that.hasValue()) {
+ using std::swap;
+ swap(value(), that.value());
+ } else if (hasValue()) {
+ that.emplace(std::move(value()));
+ reset();
+ } else if (that.hasValue()) {
+ emplace(std::move(that.value()));
+ that.reset();
+ }
+ }
+
+ FOLLY_CPP14_CONSTEXPR const Value& value() const & {
require_value();
return *storage_.value_pointer();
}
- Value& value() & {
+ FOLLY_CPP14_CONSTEXPR Value& value() & {
require_value();
return *storage_.value_pointer();
}
- Value&& value() && {
+ FOLLY_CPP14_CONSTEXPR Value&& value() && {
require_value();
return std::move(*storage_.value_pointer());
}
- const Value&& value() const && {
+ FOLLY_CPP14_CONSTEXPR const Value&& value() const && {
require_value();
return std::move(*storage_.value_pointer());
}
}
Value* get_pointer() && = delete;
- bool hasValue() const noexcept {
+ FOLLY_CPP14_CONSTEXPR bool has_value() const noexcept {
return storage_.hasValue();
}
- explicit operator bool() const noexcept {
- return hasValue();
+ FOLLY_CPP14_CONSTEXPR bool hasValue() const noexcept {
+ return has_value();
+ }
+
+ FOLLY_CPP14_CONSTEXPR explicit operator bool() const noexcept {
+ return has_value();
}
- const Value& operator*() const & {
+ FOLLY_CPP14_CONSTEXPR const Value& operator*() const & {
return value();
}
- Value& operator*() & {
+ FOLLY_CPP14_CONSTEXPR Value& operator*() & {
return value();
}
- const Value&& operator*() const && {
+ FOLLY_CPP14_CONSTEXPR const Value&& operator*() const && {
return std::move(value());
}
- Value&& operator*() && {
+ FOLLY_CPP14_CONSTEXPR Value&& operator*() && {
return std::move(value());
}
- const Value* operator->() const {
+ FOLLY_CPP14_CONSTEXPR const Value* operator->() const {
return &value();
}
- Value* operator->() {
+ FOLLY_CPP14_CONSTEXPR Value* operator->() {
return &value();
}
// Return a copy of the value if set, or a given default if not.
template <class U>
- Value value_or(U&& dflt) const & {
+ FOLLY_CPP14_CONSTEXPR Value value_or(U&& dflt) const & {
if (storage_.hasValue()) {
return *storage_.value_pointer();
}
}
template <class U>
- Value value_or(U&& dflt) && {
+ FOLLY_CPP14_CONSTEXPR Value value_or(U&& dflt) && {
if (storage_.hasValue()) {
return std::move(*storage_.value_pointer());
}
}
template <class... Args>
- void construct(Args&&... args) {
+ Value& construct(Args&&... args) {
new (raw_pointer()) Value(std::forward<Args>(args)...);
this->hasValue_ = true;
+ return *launder(reinterpret_cast<Value*>(this->value_));
}
private:
}
template <class T>
-void swap(Optional<T>& a, Optional<T>& b) {
- if (a.hasValue() && b.hasValue()) {
- // both full
- using std::swap;
- swap(a.value(), b.value());
- } else if (a.hasValue() || b.hasValue()) {
- std::swap(a, b); // fall back to default implementation if they're mixed.
- }
+void swap(Optional<T>& a, Optional<T>& b) noexcept(noexcept(a.swap(b))) {
+ a.swap(b);
}
template <class T, class Opt = Optional<typename std::decay<T>::type>>
-Opt make_optional(T&& v) {
+constexpr Opt make_optional(T&& v) {
return Opt(std::forward<T>(v));
}
// Comparisons.
template <class U, class V>
-bool operator==(const Optional<U>& a, const V& b) {
+constexpr bool operator==(const Optional<U>& a, const V& b) {
return a.hasValue() && a.value() == b;
}
template <class U, class V>
-bool operator!=(const Optional<U>& a, const V& b) {
+constexpr bool operator!=(const Optional<U>& a, const V& b) {
return !(a == b);
}
template <class U, class V>
-bool operator==(const U& a, const Optional<V>& b) {
+constexpr bool operator==(const U& a, const Optional<V>& b) {
return b.hasValue() && b.value() == a;
}
template <class U, class V>
-bool operator!=(const U& a, const Optional<V>& b) {
+constexpr bool operator!=(const U& a, const Optional<V>& b) {
return !(a == b);
}
template <class U, class V>
-bool operator==(const Optional<U>& a, const Optional<V>& b) {
+FOLLY_CPP14_CONSTEXPR bool operator==(
+ const Optional<U>& a,
+ const Optional<V>& b) {
if (a.hasValue() != b.hasValue()) {
return false;
}
}
template <class U, class V>
-bool operator!=(const Optional<U>& a, const Optional<V>& b) {
+constexpr bool operator!=(const Optional<U>& a, const Optional<V>& b) {
return !(a == b);
}
template <class U, class V>
-bool operator<(const Optional<U>& a, const Optional<V>& b) {
+FOLLY_CPP14_CONSTEXPR bool operator<(
+ const Optional<U>& a,
+ const Optional<V>& b) {
if (a.hasValue() != b.hasValue()) {
return a.hasValue() < b.hasValue();
}
}
template <class U, class V>
-bool operator>(const Optional<U>& a, const Optional<V>& b) {
+constexpr bool operator>(const Optional<U>& a, const Optional<V>& b) {
return b < a;
}
template <class U, class V>
-bool operator<=(const Optional<U>& a, const Optional<V>& b) {
+constexpr bool operator<=(const Optional<U>& a, const Optional<V>& b) {
return !(b < a);
}
template <class U, class V>
-bool operator>=(const Optional<U>& a, const Optional<V>& b) {
+constexpr bool operator>=(const Optional<U>& a, const Optional<V>& b) {
return !(a < b);
}
// Comparisons with none
template <class V>
-bool operator==(const Optional<V>& a, None) noexcept {
+constexpr bool operator==(const Optional<V>& a, None) noexcept {
return !a.hasValue();
}
template <class V>
-bool operator==(None, const Optional<V>& a) noexcept {
+constexpr bool operator==(None, const Optional<V>& a) noexcept {
return !a.hasValue();
}
template <class V>
-bool operator<(const Optional<V>&, None) noexcept {
+constexpr bool operator<(const Optional<V>&, None) noexcept {
return false;
}
template <class V>
-bool operator<(None, const Optional<V>& a) noexcept {
+constexpr bool operator<(None, const Optional<V>& a) noexcept {
return a.hasValue();
}
template <class V>
-bool operator>(const Optional<V>& a, None) noexcept {
+constexpr bool operator>(const Optional<V>& a, None) noexcept {
return a.hasValue();
}
template <class V>
-bool operator>(None, const Optional<V>&) noexcept {
+constexpr bool operator>(None, const Optional<V>&) noexcept {
return false;
}
template <class V>
-bool operator<=(None, const Optional<V>&) noexcept {
+constexpr bool operator<=(None, const Optional<V>&) noexcept {
return true;
}
template <class V>
-bool operator<=(const Optional<V>& a, None) noexcept {
+constexpr bool operator<=(const Optional<V>& a, None) noexcept {
return !a.hasValue();
}
template <class V>
-bool operator>=(const Optional<V>&, None) noexcept {
+constexpr bool operator>=(const Optional<V>&, None) noexcept {
return true;
}
template <class V>
-bool operator>=(None, const Optional<V>& a) noexcept {
+constexpr bool operator>=(None, const Optional<V>& a) noexcept {
return !a.hasValue();
}
return o_.hasValue();
}
Value await_resume() {
- return o_.value();
+ return std::move(o_.value());
}
- template <typename CoroHandle>
- void await_suspend(CoroHandle h) const {
- // make sure the coroutine returns an empty Optional:
- h.promise().value_->clear();
- // Abort the rest of the coroutine:
+
+ // Explicitly only allow suspension into an OptionalPromise
+ template <typename U>
+ void await_suspend(
+ std::experimental::coroutine_handle<OptionalPromise<U>> h) const {
+ // Abort the rest of the coroutine. resume() is not going to be called
h.destroy();
}
};
}
} // namespace folly
-// This makes std::optional<Value> useable as a coroutine return type..
+// This makes folly::Optional<Value> useable as a coroutine return type..
FOLLY_NAMESPACE_STD_BEGIN
namespace experimental {
template <typename Value, typename... Args>
struct coroutine_traits<folly::Optional<Value>, Args...> {
using promise_type = folly::detail::OptionalPromise<Value>;
};
-} // experimental
+} // namespace experimental
FOLLY_NAMESPACE_STD_END
#endif // FOLLY_HAS_COROUTINES
projects / folly.git / blobdiff