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Merge pull request #8365 from obsidiansystems/proto-structs

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Revert "Revert "Use template structs instead of phantoms""
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Théophane Hufschmitt 2023-05-22 09:34:34 +02:00 • committed by GitHub
commit 673fe85976
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10 changed files with 182 additions and 151 deletions
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113
src/libstore/worker-protocol.hh
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@ -88,40 +88,71 @@ enum TrustedFlag : bool;
/**
* Used to guide overloading
* Data type for canonical pairs of serializers for the worker protocol.
*
* See https://en.cppreference.com/w/cpp/language/adl for the broader
* concept of what is going on here.
*/
template<typename T>
struct Phantom {};
struct WorkerProto {
static T read(const Store & store, Source & from);
static void write(const Store & store, Sink & out, const T & t);
};
/**
* Wrapper function around `WorkerProto<T>::write` that allows us to
* infer the type instead of having to write it down explicitly.
*/
template<typename T>
void workerProtoWrite(const Store & store, Sink & out, const T & t)
{
WorkerProto<T>::write(store, out, t);
}
namespace worker_proto {
/* FIXME maybe move more stuff inside here */
/**
* Declare a canonical serializer pair for the worker protocol.
*
* We specialize the struct merely to indicate that we are implementing
* the function for the given type.
*
* Some sort of `template<...>` must be used with the caller for this to
* be legal specialization syntax. See below for what that looks like in
* practice.
*/
#define MAKE_WORKER_PROTO(T) \
struct WorkerProto< T > { \
static T read(const Store & store, Source & from); \
static void write(const Store & store, Sink & out, const T & t); \
};
#define MAKE_WORKER_PROTO(TEMPLATE, T) \
TEMPLATE T read(const Store & store, Source & from, Phantom< T > _); \
TEMPLATE void write(const Store & store, Sink & out, const T & str)
template<>
MAKE_WORKER_PROTO(std::string);
template<>
MAKE_WORKER_PROTO(StorePath);
template<>
MAKE_WORKER_PROTO(ContentAddress);
template<>
MAKE_WORKER_PROTO(DerivedPath);
template<>
MAKE_WORKER_PROTO(Realisation);
template<>
MAKE_WORKER_PROTO(DrvOutput);
template<>
MAKE_WORKER_PROTO(BuildResult);
template<>
MAKE_WORKER_PROTO(KeyedBuildResult);
template<>
MAKE_WORKER_PROTO(std::optional<TrustedFlag>);
MAKE_WORKER_PROTO(, std::string);
MAKE_WORKER_PROTO(, StorePath);
MAKE_WORKER_PROTO(, ContentAddress);
MAKE_WORKER_PROTO(, DerivedPath);
MAKE_WORKER_PROTO(, Realisation);
MAKE_WORKER_PROTO(, DrvOutput);
MAKE_WORKER_PROTO(, BuildResult);
MAKE_WORKER_PROTO(, KeyedBuildResult);
MAKE_WORKER_PROTO(, std::optional<TrustedFlag>);
template<typename T>
MAKE_WORKER_PROTO(std::vector<T>);
template<typename T>
MAKE_WORKER_PROTO(std::set<T>);
MAKE_WORKER_PROTO(template<typename T>, std::vector<T>);
MAKE_WORKER_PROTO(template<typename T>, std::set<T>);
#define X_ template<typename K, typename V>
#define Y_ std::map<K, V>
MAKE_WORKER_PROTO(X_, Y_);
template<typename K, typename V>
#define X_ std::map<K, V>
MAKE_WORKER_PROTO(X_);
#undef X_
#undef Y_
/**
* These use the empty string for the null case, relying on the fact
@ -137,72 +168,72 @@ MAKE_WORKER_PROTO(X_, Y_);
* worker protocol harder to implement in other languages where such
* specializations may not be allowed.
*/
MAKE_WORKER_PROTO(, std::optional<StorePath>);
MAKE_WORKER_PROTO(, std::optional<ContentAddress>);
template<>
MAKE_WORKER_PROTO(std::optional<StorePath>);
template<>
MAKE_WORKER_PROTO(std::optional<ContentAddress>);
template<typename T>
std::vector<T> read(const Store & store, Source & from, Phantom<std::vector<T>> _)
std::vector<T> WorkerProto<std::vector<T>>::read(const Store & store, Source & from)
{
std::vector<T> resSet;
auto size = readNum<size_t>(from);
while (size--) {
resSet.push_back(read(store, from, Phantom<T> {}));
resSet.push_back(WorkerProto<T>::read(store, from));
}
return resSet;
}
template<typename T>
void write(const Store & store, Sink & out, const std::vector<T> & resSet)
void WorkerProto<std::vector<T>>::write(const Store & store, Sink & out, const std::vector<T> & resSet)
{
out << resSet.size();
for (auto & key : resSet) {
write(store, out, key);
WorkerProto<T>::write(store, out, key);
}
}
template<typename T>
std::set<T> read(const Store & store, Source & from, Phantom<std::set<T>> _)
std::set<T> WorkerProto<std::set<T>>::read(const Store & store, Source & from)
{
std::set<T> resSet;
auto size = readNum<size_t>(from);
while (size--) {
resSet.insert(read(store, from, Phantom<T> {}));
resSet.insert(WorkerProto<T>::read(store, from));
}
return resSet;
}
template<typename T>
void write(const Store & store, Sink & out, const std::set<T> & resSet)
void WorkerProto<std::set<T>>::write(const Store & store, Sink & out, const std::set<T> & resSet)
{
out << resSet.size();
for (auto & key : resSet) {
write(store, out, key);
WorkerProto<T>::write(store, out, key);
}
}
template<typename K, typename V>
std::map<K, V> read(const Store & store, Source & from, Phantom<std::map<K, V>> _)
std::map<K, V> WorkerProto<std::map<K, V>>::read(const Store & store, Source & from)
{
std::map<K, V> resMap;
auto size = readNum<size_t>(from);
while (size--) {
auto k = read(store, from, Phantom<K> {});
auto v = read(store, from, Phantom<V> {});
auto k = WorkerProto<K>::read(store, from);
auto v = WorkerProto<V>::read(store, from);
resMap.insert_or_assign(std::move(k), std::move(v));
}
return resMap;
}
template<typename K, typename V>
void write(const Store & store, Sink & out, const std::map<K, V> & resMap)
void WorkerProto<std::map<K, V>>::write(const Store & store, Sink & out, const std::map<K, V> & resMap)
{
out << resMap.size();
for (auto & i : resMap) {
write(store, out, i.first);
write(store, out, i.second);
WorkerProto<K>::write(store, out, i.first);
WorkerProto<V>::write(store, out, i.second);
}
}
}
}