Separated orchid-host and orchid-extension

This is an architectural change that allows me to implment specifics first and generalize along observed symmetries in orchid-base

orchid-host/src/child.rs

@@ -0,0 +1,28 @@
+use std::io;
+use std::sync::Mutex;
+use std::{mem, process};
+
+use orchid_base::msg::{recv_msg, send_msg};
+
+pub struct SharedChild {
+  child: process::Child,
+  stdin: Mutex<process::ChildStdin>,
+  stdout: Mutex<process::ChildStdout>,
+}
+impl SharedChild {
+  pub fn new(cmd: &mut process::Command) -> io::Result<Self> {
+    let mut child = cmd.stdin(process::Stdio::piped()).stdout(process::Stdio::piped()).spawn()?;
+    let stdin = Mutex::new(child.stdin.take().expect("Piped stdin above"));
+    let stdout = Mutex::new(child.stdout.take().expect("Piped stdout above"));
+    Ok(Self { stdin, stdout, child })
+  }
+
+  pub fn send_msg(&self, msg: &[u8]) -> io::Result<()> {
+    send_msg(&mut *self.stdin.lock().unwrap(), msg)
+  }
+
+  pub fn recv_msg(&self) -> io::Result<Vec<u8>> { recv_msg(&mut *self.stdout.lock().unwrap()) }
+}
+impl Drop for SharedChild {
+  fn drop(&mut self) { mem::drop(self.child.kill()) }
+}