At the risk of forking another thread to discuss the same problem, I’m including my progress from today. There seems to have been a bunch of discussion on this before!
In my case, I’m bouncing between two different errors as I decide if I need to impl Resource or if I need to make a new type that mimics GraphDb with the necessary trait (seems likely).
base code:
use rustler::ResourceArc;
use rustler::Resource;
use rustler::{Env};
use sparrowdb::GraphDb;
rustler::atoms! { ok, error }
rustler::init!("Elixir.Spare", [open]);
enum Response {
Success(ResourceArc<sparrowdb::GraphDb>),
Failure(String),
}
// #[rustler::nif(schedule = "DirtyCPU")]
// #[rustler::nif(schedule = "DirtyIo")]
#[rustler::nif]
fn open(base: &str) -> Response {
match GraphDb::open(std::path::Path::new(base)) {
Ok(graph) => Response.Success(ResourceArc::new(graph)),
Error(e) => Response.Failure(e.to_string())
}
}
I may be soooooo off here, this is a hodgepodge from combining examples.
error[E0277]: the trait bound `GraphDb: Resource` is not satisfied
--> native/spare/src/lib.rs:20:54
|
20 | Ok(graph) => Response.Success(ResourceArc::new(graph)),
| ---------------- ^^^^^ the trait `Resource` is not implemented for `GraphDb`
| |
| required by a bound introduced by this call
|
note: required by a bound in `ResourceArc::<T>::new`
--> /home/calliope/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/rustler-0.38.0/src/resource/arc.rs:39:8
|
39 | T: Resource,
| ^^^^^^^^ required by this bound in `ResourceArc::<T>::new`
...
43 | pub fn new(data: T) -> Self {
| --- required by a bound in this associated function
error[E0277]: the trait bound `GraphDb: Resource` is not satisfied
--> native/spare/src/lib.rs:20:37
|
20 | Ok(graph) => Response.Success(ResourceArc::new(graph)),
| ^^^^^^^^^^^^^^^^^^^^^^^ the trait `Resource` is not implemented for `GraphDb`
|
note: required by a bound in `ResourceArc`
--> /home/calliope/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/rustler-0.38.0/src/resource/arc.rs:27:8
|
25 | pub struct ResourceArc<T>
| ----------- required by a bound in this struct
26 | where
27 | T: Resource,
| ^^^^^^^^ required by this bound in `ResourceArc`
Then, if I include this impl Resource, the error changes:
#[rustler::resource_impl]
impl Resource for sparrowdb::GraphDb
{
fn destructor(self, env: Env<'_>) {
drop(self)
}
}
error[E0117]: only traits defined in the current crate can be implemented for types defined outside of the crate
--> native/spare/src/lib.rs:26:1
|
26 | impl Resource for sparrowdb::GraphDb
| ^^^^^^^^^^^^^^^^^^------------------
| |
| `GraphDb` is not defined in the current crate
|
= note: impl doesn't have any local type before any uncovered type parameters
= note: for more information see https://doc.rust-lang.org/reference/items/implementations.html#orphan-rules
= note: define and implement a trait or new type instead
