static ERL_NIF_TERM open_nif(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[]) {
posix_errno_t posix_errno;
efile_data_t *d;
ErlNifPid controlling_process;
enum efile_modes_t modes;
ERL_NIF_TERM result;
efile_path_t path;
if(argc != 2 || !enif_is_list(env, argv[1])) {
return enif_make_badarg(env);
}
modes = efile_translate_modelist(env, argv[1]);
if((posix_errno = efile_marshal_path(env, argv[0], &path))) {
return posix_error_to_tuple(env, posix_errno);
} else if((posix_errno = efile_open(&path, modes, efile_resource_type, &d))) {
return posix_error_to_tuple(env, posix_errno);
}
result = enif_make_resource(env, d);
enif_release_resource(d);
enif_self(env, &controlling_process);
if(enif_monitor_process(env, d, &controlling_process, &d->monitor)) {
return posix_error_to_tuple(env, EINVAL);
}
return enif_make_tuple2(env, am_ok, result);
}
static ERL_NIF_TERM open_nif(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[]) {
posix_errno_t posix_errno;
efile_data_t *d;
ErlNifPid controlling_process;
enum efile_modes_t modes;
ERL_NIF_TERM result;
efile_path_t path;
ASSERT(argc == 2);
if(!enif_is_list(env, argv[1])) {
return enif_make_badarg(env);
}
modes = efile_translate_modelist(env, argv[1]);
if((posix_errno = efile_marshal_path(env, argv[0], &path))) {
return posix_error_to_tuple(env, posix_errno);
} else if((posix_errno = efile_open(&path, modes, efile_resource_type, &d))) {
return posix_error_to_tuple(env, posix_errno);
}
enif_self(env, &controlling_process);
if(enif_monitor_process(env, d, &controlling_process, &d->monitor)) {
/* We need to close the file manually as we haven't registered a
* destructor. */
posix_errno_t ignored;
erts_atomic32_set_acqb(&d->state, EFILE_STATE_CLOSED);
efile_close(d, &ignored);
return posix_error_to_tuple(env, EINVAL);
}
/* Note that we do not call enif_release_resource at this point. While it's
* normally safe to leave resource management to the GC, efile_close is a
* blocking operation which must not be done in the GC callback, and we
* can't defer it as the resource is gone as soon as it returns.
*
* We instead keep the resource alive until efile_close is called, after
* which it's safe to leave things to the GC. If the controlling process
* were to die before the user had a chance to close their file, the above
* monitor will tell the erts_prim_file process to close it for them. */
result = enif_make_resource(env, d);
return enif_make_tuple2(env, am_ok, result);
}