nix-super/src/libutil/rust-ffi.hh

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2019-09-11 13:43:07 +03:00
#include "serialise.hh"
namespace rust {
// Depending on the internal representation of Rust slices is slightly
// evil...
template<typename T>
struct Slice
{
T * ptr;
size_t size;
Slice(T * ptr, size_t size) : ptr(ptr), size(size)
{
assert(ptr);
}
};
struct StringSlice : Slice<char>
{
StringSlice(const std::string & s): Slice((char *) s.data(), s.size()) {}
};
struct Source
{
size_t (*fun)(void * source_this, rust::Slice<uint8_t> data);
nix::Source * _this;
Source(nix::Source & _this)
: fun(sourceWrapper), _this(&_this)
{}
// FIXME: how to propagate exceptions?
static size_t sourceWrapper(void * _this, rust::Slice<uint8_t> data)
{
auto n = ((nix::Source *) _this)->read(data.ptr, data.size);
return n;
}
};
/* C++ representation of Rust's Result<T, CppException>. */
template<typename T>
struct Result
{
unsigned int tag;
union {
T data;
std::exception_ptr * exc;
};
/* Rethrow the wrapped exception or return the wrapped value. */
T unwrap()
{
if (tag == 0)
return data;
else if (tag == 1)
std::rethrow_exception(*exc);
else
abort();
}
};
template<typename T>
struct CBox
{
T * ptr;
T * operator ->()
{
return ptr;
}
CBox(T * ptr) : ptr(ptr) { }
CBox(const CBox &) = delete;
CBox(CBox &&) = delete;
~CBox()
{
free(ptr);
}
};
}