Move printer communication to separate function

red/src/lib.rs

@@ -1,3 +1,4 @@
+#![warn(missing_docs)]
 pub mod gamepad;
 pub mod jogger;
 pub mod printer;

red/src/main.rs

@@ -1,4 +1,5 @@
 #![warn(rust_2018_idioms)]
+#![warn(missing_docs)]
 use futures::never::Never;
 use i2c_linux::I2c;
 use red::gamepad;
@@ -33,7 +34,6 @@ const I2C_REGISTER_SPINDLE_SPEED: u8 = 0;
 //  SMBUS_WORD_DATA
 //  SMBUS_I2C_BLOCK
 //  SMBUS_EMUL
-
 #[tokio::main]
 async fn main() -> Never {
     println!("Entering App");

red/src/printer/mod.rs

@@ -8,7 +8,7 @@ use std::{fmt::Write, io, rc::Rc, str};
 use tokio;
 use tokio::sync::mpsc::{channel, Receiver, Sender};
 use tokio::time::timeout;
-use tokio_serial::SerialPortBuilderExt;
+use tokio_serial::{SerialPortBuilderExt, SerialStream};
 use tokio_util::codec::{Decoder, Encoder};
 
 pub use gcode::{GcodeCommand, GcodeReply};
@@ -58,11 +58,43 @@ impl Printer {
         port.set_exclusive(false)
             .expect("Unable to set serial port exclusive to false");
 
-        let connection = LineCodec.framed(port);
+        // commands that go to the printer
         let (printer_in_tx, mut printer_in_rx) = channel::<Box<dyn GcodeCommand>>(32);
+        // replies that come from the printer
         let (printer_out_tx, printer_out_rx) = channel::<Result<GcodeReply, PrinterError>>(32);
 
-        tokio::spawn(async move {
+        tokio::spawn(printer_communication_task(
+            port,
+            printer_in_rx,
+            printer_out_tx,
+        ));
+
+        Ok(Printer {
+            printer_in: printer_in_tx,
+            printer_out: printer_out_rx,
+            state: Rc::new(State {
+                position: (0.0, 0.0, 0.0, 0.0),
+            }),
+        })
+    }
+}
+
+/// Pull commands from `user_commands`, write them to the printer and send the reply back through
+/// `printer_replies`.
+///
+///
+/// Arguments:
+///
+/// * `port`: Serial port that is connected to a printer running Marlin
+/// * `user_commands`: Channel for the user to submit their GCODE
+/// * `printer_replies`: Replies from the printer the the submitted GCODE. These always correspond
+/// to the incoming commands in order that they were received.
+async fn printer_communication_task(
+    port: SerialStream,
+    mut user_commands: Receiver<Box<dyn GcodeCommand>>,
+    printer_replies: Sender<Result<GcodeReply, PrinterError>>,
+) {
+    let connection = LineCodec.framed(port);
     let (mut serial_tx, mut serial_rx) = connection.split();
 
     // The printer will send some info after connecting. We need to wait for this
@@ -86,9 +118,7 @@ impl Printer {
             }
         } else {
             // TODO: Check if port is good by sending some harmless gcode
-                    println!(
+            println!("Reading from serial port timed out. Printer might already be initialized.");
-                        "Reading from serial port timed out. Printer might already be initialized."
-                    );
             println!("Sending G91 command");
             serial_tx
                 .send(G91Command.command() + "\n")
@@ -97,7 +127,7 @@ impl Printer {
         }
     }
 
-            while let Some(command) = printer_in_rx.recv().await {
+    while let Some(command) = user_commands.recv().await {
         let command_text = format!("{}\n", command.command());
         println!("sending in: {:?}", command_text);
         serial_tx.send(command_text).await.unwrap();
@@ -107,7 +137,7 @@ impl Printer {
             if line.contains("ok") {
                 let reply = command.parse_reply(&reply);
                 println!("got reply: {:?}", reply);
-                        printer_out_tx
+                printer_replies
                     .send(reply.map_err(PrinterError::GcodeReply))
                     .await
                     .unwrap();
@@ -117,16 +147,6 @@ impl Printer {
             }
         }
     }
-        });
-
-        Ok(Printer {
-            printer_in: printer_in_tx,
-            printer_out: printer_out_rx,
-            state: Rc::new(State {
-                position: (0.0, 0.0, 0.0, 0.0),
-            }),
-        })
-    }
 }
 
 struct LineCodec;