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// Copyright 2015-2019 Capital One Services, LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use crate::host::{Invocation, InvocationResponse};
use crossbeam_channel::{Receiver, Sender};
use std::error::Error;
use wascc_codec::capabilities::Dispatcher;

/// A dispatcher is given to each capability provider, allowing it to send
/// commands in to the guest module (via the muxer) and await replies. This dispatch
/// is one way, and is _not_ used for the guest module to send commands to capabilities
#[derive(Clone)]
pub(crate) struct WasccNativeDispatcher {
    resp_r: Receiver<InvocationResponse>,
    invoc_s: Sender<Invocation>,
    capid: String,
}

impl WasccNativeDispatcher {
    pub fn new(
        resp_r: Receiver<InvocationResponse>,
        invoc_s: Sender<Invocation>,
        capid: &str,
    ) -> Self {
        WasccNativeDispatcher {
            resp_r,
            invoc_s,
            capid: capid.to_string(),
        }
    }
}

impl Dispatcher for WasccNativeDispatcher {
    fn dispatch(&self, op: &str, msg: &[u8]) -> Result<Vec<u8>, Box<dyn Error>> {
        trace!(
            "Dispatching operation '{}' ({} bytes) to actor",
            op,
            msg.len()
        );
        let inv = Invocation::new(self.capid.to_string(), op, msg.to_vec());
        self.invoc_s.send(inv)?;
        let resp = self.resp_r.recv();
        match resp {
            Ok(r) => match r.error {
                Some(e) => Err(format!("Invocation failure: {}", e).into()),
                None => Ok(r.msg),
            },
            Err(e) => Err(Box::new(e)),
        }
    }
}