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Changed non_flow_ref to flow_ref for clarity. 

Also updated comment to explain that std::is_trivially_copyable
cannot be used to determine whether or not a type is a flow ref.
This commit is contained in:
sfc-gh-tclinkenbeard 2020-05-23 22:57:41 -07:00
parent 131534e4a1
commit 8a98ea3320
2 changed files with 14 additions and 12 deletions
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2
fdbclient/FDBTypes.h
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@ -80,7 +80,7 @@ struct Tag {
};
template <>
struct non_flow_ref<Tag> : std::integral_constant<bool, true> {};
struct flow_ref<Tag> : std::integral_constant<bool, false> {};
#pragma pack(pop)

24
flow/Arena.h
View File

@ -700,16 +700,18 @@ inline bool operator >= ( const StringRef& lhs, const StringRef& rhs ) { return
// This trait is used by VectorRef to determine if deep copy constructor should recursively
// call deep copies of each element.
// TODO: There should be an easier way to identify the difference between
// flow_ref and non-flow_ref types.
//
// TODO: There should be an easier way to identify the difference between flow_ref and non-flow_ref types.
// std::is_trivially_copyable does not work because some flow_ref types are trivially copyable
// and some non-flow_ref types are not trivially copyable.
template <typename T>
struct non_flow_ref : std::is_fundamental<T> {};
struct flow_ref : std::integral_constant<bool, !std::is_fundamental_v<T>> {};
template <>
struct non_flow_ref<UID> : std::integral_constant<bool, true> {};
struct flow_ref<UID> : std::integral_constant<bool, false> {};
template <class A, class B>
struct non_flow_ref<std::pair<A, B>> : std::integral_constant<bool, true> {};
struct flow_ref<std::pair<A, B>> : std::integral_constant<bool, false> {};
template<class T>
struct string_serialized_traits : std::false_type {
@ -800,9 +802,9 @@ public:
return *this;
}
// Arena constructor for non-Ref types, identified by non_flow_ref
// Arena constructor for non-Ref types, identified by !flow_ref
template <class T2 = T, VecSerStrategy S>
VectorRef(Arena& p, const VectorRef<T, S>& toCopy, typename std::enable_if<non_flow_ref<T2>::value, int>::type = 0)
VectorRef(Arena& p, const VectorRef<T, S>& toCopy, typename std::enable_if<!flow_ref<T2>::value, int>::type = 0)
: VPS(toCopy), data((T*)new (p) uint8_t[sizeof(T) * toCopy.size()]), m_size(toCopy.size()),
m_capacity(toCopy.size()) {
if (m_size > 0) {
@ -812,7 +814,7 @@ public:
// Arena constructor for Ref types, which must have an Arena constructor
template <class T2 = T, VecSerStrategy S>
VectorRef(Arena& p, const VectorRef<T, S>& toCopy, typename std::enable_if<!non_flow_ref<T2>::value, int>::type = 0)
VectorRef(Arena& p, const VectorRef<T, S>& toCopy, typename std::enable_if<flow_ref<T2>::value, int>::type = 0)
: VPS(), data((T*)new (p) uint8_t[sizeof(T) * toCopy.size()]), m_size(toCopy.size()), m_capacity(toCopy.size()) {
for (int i = 0; i < m_size; i++) {
auto ptr = new (&data[i]) T(p, toCopy[i]);
@ -942,15 +944,15 @@ public:
if (size > m_capacity) reallocate(p, size);
}
// expectedSize() for non-Ref types, identified by non_flow_ref
// expectedSize() for non-Ref types, identified by !flow_ref
template <class T2 = T>
typename std::enable_if<non_flow_ref<T2>::value, size_t>::type expectedSize() const {
typename std::enable_if<!flow_ref<T2>::value, size_t>::type expectedSize() const {
return sizeof(T) * m_size;
}
// expectedSize() for Ref types, which must in turn have expectedSize() implemented.
template <class T2 = T>
typename std::enable_if<!non_flow_ref<T2>::value, size_t>::type expectedSize() const {
typename std::enable_if<flow_ref<T2>::value, size_t>::type expectedSize() const {
size_t t = sizeof(T) * m_size;
for (int i = 0; i < m_size; i++) t += data[i].expectedSize();
return t;