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

#if 0
#include "logging.hh"
#include "rust-ffi.hh"

extern "C" std::exception_ptr * make_error(rust::StringSlice s)
{
    return new std::exception_ptr(std::make_exception_ptr(nix::Error(std::string(s.ptr, s.size))));
}

extern "C" void destroy_error(std::exception_ptr * ex)
{
    free(ex);
}

namespace rust {

std::ostream & operator << (std::ostream & str, const String & s)
{
    str << (std::string_view) s;
    return str;
}

}
#endif
StorePath: Rewrite in C++ On nix-env -qa -f '<nixpkgs>', this reduces maximum RSS by 20970 KiB and runtime by 0.8%. This is mostly because we're not parsing the hash part as a hash anymore (just validating that it consists of base-32 characters). Also, replace storePathToHash() by StorePath::hashPart(). 2020-06-16 15:16:39 +03:00			`#if 0`
More Rust FFI adventures We can now convert Rust Errors to C++ exceptions. At the Rust->C++ FFI boundary, Result<T, Error> will cause Error to be converted to and thrown as a C++ exception. 2019-09-11 02:15:20 +03:00			`#include "logging.hh"`
Move code around 2019-09-11 14:10:46 +03:00			`#include "rust-ffi.hh"`
More Rust FFI adventures We can now convert Rust Errors to C++ exceptions. At the Rust->C++ FFI boundary, Result<T, Error> will cause Error to be converted to and thrown as a C++ exception. 2019-09-11 02:15:20 +03:00
			`extern "C" std::exception_ptr * make_error(rust::StringSlice s)`
			`{`
Make the Store API more type-safe Most functions now take a StorePath argument rather than a Path (which is just an alias for std::string). The StorePath constructor ensures that the path is syntactically correct (i.e. it looks like <store-dir>/<base32-hash>-<name>). Similarly, functions like buildPaths() now take a StorePathWithOutputs, rather than abusing Path by adding a '!<outputs>' suffix. Note that the StorePath type is implemented in Rust. This involves some hackery to allow Rust values to be used directly in C++, via a helper type whose destructor calls the Rust type's drop() function. The main issue is the dynamic nature of C++ move semantics: after we have moved a Rust value, we should not call the drop function on the original value. So when we move a value, we set the original value to bitwise zero, and the destructor only calls drop() if the value is not bitwise zero. This should be sufficient for most types. Also lots of minor cleanups to the C++ API to make it more modern (e.g. using std::optional and std::string_view in some places). 2019-12-05 20:11:09 +02:00			`return new std::exception_ptr(std::make_exception_ptr(nix::Error(std::string(s.ptr, s.size))));`
			`}`

Don't leak exceptions 2019-12-13 20:05:09 +02:00			`extern "C" void destroy_error(std::exception_ptr * ex)`
			`{`
			`free(ex);`
			`}`

Make the Store API more type-safe Most functions now take a StorePath argument rather than a Path (which is just an alias for std::string). The StorePath constructor ensures that the path is syntactically correct (i.e. it looks like <store-dir>/<base32-hash>-<name>). Similarly, functions like buildPaths() now take a StorePathWithOutputs, rather than abusing Path by adding a '!<outputs>' suffix. Note that the StorePath type is implemented in Rust. This involves some hackery to allow Rust values to be used directly in C++, via a helper type whose destructor calls the Rust type's drop() function. The main issue is the dynamic nature of C++ move semantics: after we have moved a Rust value, we should not call the drop function on the original value. So when we move a value, we set the original value to bitwise zero, and the destructor only calls drop() if the value is not bitwise zero. This should be sufficient for most types. Also lots of minor cleanups to the C++ API to make it more modern (e.g. using std::optional and std::string_view in some places). 2019-12-05 20:11:09 +02:00			`namespace rust {`

			`std::ostream & operator << (std::ostream & str, const String & s)`
			`{`
			`str << (std::string_view) s;`
			`return str;`
More Rust FFI adventures We can now convert Rust Errors to C++ exceptions. At the Rust->C++ FFI boundary, Result<T, Error> will cause Error to be converted to and thrown as a C++ exception. 2019-09-11 02:15:20 +03:00			`}`

			`}`
StorePath: Rewrite in C++ On nix-env -qa -f '<nixpkgs>', this reduces maximum RSS by 20970 KiB and runtime by 0.8%. This is mostly because we're not parsing the hash part as a hash anymore (just validating that it consists of base-32 characters). Also, replace storePathToHash() by StorePath::hashPart(). 2020-06-16 15:16:39 +03:00			`#endif`