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#pragma once
///@file
#include "common-protocol.hh"
namespace nix {
#define SERVE_MAGIC_1 0x390c9deb
#define SERVE_MAGIC_2 0x5452eecb
#define SERVE_PROTOCOL_VERSION (2 << 8 | 7)
#define GET_PROTOCOL_MAJOR(x) ((x) & 0xff00)
#define GET_PROTOCOL_MINOR(x) ((x) & 0x00ff)
class Store;
struct Source;
/**
* The "serve protocol", used by ssh:// stores.
*
* This `struct` is basically just a `namespace`; We use a type rather
* than a namespace just so we can use it as a template argument.
*/
struct ServeProto
{
/**
* Enumeration of all the request types for the protocol.
*/
enum struct Command : uint64_t;
/**
* Version type for the protocol.
*
* @todo Convert to struct with separate major vs minor fields.
*/
using Version = unsigned int;
/**
* A unidirectional read connection, to be used by the read half of the
* canonical serializers below.
*/
struct ReadConn {
Source & from;
Version version;
};
/**
* A unidirectional write connection, to be used by the write half of the
* canonical serializers below.
*/
struct WriteConn {
Sink & to;
Version version;
};
/**
* Data type for canonical pairs of serialisers for the serve protocol.
*
* See https://en.cppreference.com/w/cpp/language/adl for the broader
* concept of what is going on here.
*/
template<typename T>
struct Serialise;
// This is the definition of `Serialise` we *want* to put here, but
// do not do so.
//
// See `worker-protocol.hh` for a longer explanation.
#if 0
{
static T read(const Store & store, ReadConn conn);
static void write(const Store & store, WriteConn conn, const T & t);
};
#endif
/**
* Wrapper function around `ServeProto::Serialise<T>::write` that allows us to
* infer the type instead of having to write it down explicitly.
*/
template<typename T>
static void write(const Store & store, WriteConn conn, const T & t)
{
ServeProto::Serialise<T>::write(store, conn, t);
}
};
enum struct ServeProto::Command : uint64_t
{
QueryValidPaths = 1,
QueryPathInfos = 2,
DumpStorePath = 3,
ImportPaths = 4,
ExportPaths = 5,
BuildPaths = 6,
QueryClosure = 7,
BuildDerivation = 8,
AddToStoreNar = 9,
};
/**
* Convenience for sending operation codes.
*
* @todo Switch to using `ServeProto::Serialize` instead probably. But
* this was not done at this time so there would be less churn.
*/
inline Sink & operator << (Sink & sink, ServeProto::Command op)
{
return sink << (uint64_t) op;
}
/**
* Convenience for debugging.
*
* @todo Perhaps render known opcodes more nicely.
*/
inline std::ostream & operator << (std::ostream & s, ServeProto::Command op)
{
return s << (uint64_t) op;
}
/**
* Declare a canonical serialiser pair for the worker protocol.
*
* We specialise 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 DECLARE_SERVE_SERIALISER(T) \
struct ServeProto::Serialise< T > \
{ \
static T read(const Store & store, ServeProto::ReadConn conn); \
static void write(const Store & store, ServeProto::WriteConn conn, const T & t); \
};
template<typename T>
DECLARE_SERVE_SERIALISER(std::vector<T>);
template<typename T>
DECLARE_SERVE_SERIALISER(std::set<T>);
template<typename... Ts>
DECLARE_SERVE_SERIALISER(std::tuple<Ts...>);
#define COMMA_ ,
template<typename K, typename V>
DECLARE_SERVE_SERIALISER(std::map<K COMMA_ V>);
#undef COMMA_
}
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