engine.rs

use crate::ecalls::EnclaveConnector;
use codec::{Decode, Encode};
use frame_common::{EcallInput, EcallOutput};

use sgx_types::sgx_enclave_id_t;

pub trait HostEngine {
    type HI: HostInput<EcallInput = Self::EI, HostOutput = Self::HO>;
    type EI: EcallInput + Encode;
    type EO: EcallOutput + Decode;
    type HO: HostOutput<EcallOutput = Self::EO>;
    const OUTPUT_MAX_LEN: usize;
    const CMD: u32;

    fn exec(input: Self::HI, eid: sgx_enclave_id_t) -> anyhow::Result<Self::HO> {
        let (ecall_input, host_output) = input.apply()?;
        let ecall_output = EnclaveConnector::new(eid, Self::OUTPUT_MAX_LEN)
            .invoke_ecall::<Self::EI, Self::EO>(Self::CMD, ecall_input)?;
        
        host_output.set_ecall_output(ecall_output)
    }
}

pub trait HostInput: Sized {
    type EcallInput: EcallInput;
    type HostOutput: HostOutput;

    fn apply(self) -> anyhow::Result<(Self::EcallInput, Self::HostOutput)>;
}

pub trait HostOutput: Sized {
    type EcallOutput: EcallOutput;

    fn set_ecall_output(self, _output: Self::EcallOutput) -> anyhow::Result<Self> {
        Ok(self)
    }
}