Add a SimpleClient, that does request/response without background tas…

…ks and URC handling (FactbirdHQ#203)

atat/src/asynch/mod.rs

@@ -1,6 +1,8 @@
 mod client;
+mod simple_client;
 
 pub use client::Client;
+pub use simple_client::SimpleClient;
 
 use crate::{AtatCmd, Error};
 

atat/src/asynch/simple_client.rs

@@ -0,0 +1,153 @@
+use super::AtatClient;
+use crate::{helpers::LossyStr, AtatCmd, Config, DigestResult, Digester, Error, Response};
+use embassy_time::{Duration, Timer};
+use embedded_io_async::{Read, Write};
+
+pub struct SimpleClient<'a, RW: Read + Write, D: Digester> {
+    rw: RW,
+    digester: D,
+    buf: &'a mut [u8],
+    pos: usize,
+    config: Config,
+    cooldown_timer: Option<Timer>,
+}
+
+impl<'a, RW: Read + Write, D: Digester> SimpleClient<'a, RW, D> {
+    pub fn new(rw: RW, digester: D, buf: &'a mut [u8], config: Config) -> Self {
+        Self {
+            rw,
+            digester,
+            buf,
+            config,
+            pos: 0,
+            cooldown_timer: None,
+        }
+    }
+
+    async fn send_request(&mut self, len: usize) -> Result<(), Error> {
+        if len < 50 {
+            debug!("Sending command: {:?}", LossyStr(&self.buf[..len]));
+        } else {
+            debug!("Sending command with long payload ({} bytes)", len);
+        }
+
+        self.wait_cooldown_timer().await;
+
+        // Write request
+        self.rw
+            .write_all(&self.buf[..len])
+            .await
+            .map_err(|_| Error::Write)?;
+        self.rw.flush().await.map_err(|_| Error::Write)?;
+
+        self.start_cooldown_timer();
+        Ok(())
+    }
+
+    async fn wait_response<'guard>(&'guard mut self) -> Result<Response<256>, Error> {
+        loop {
+            match self.rw.read(&mut self.buf[self.pos..]).await {
+                Ok(n) => {
+                    self.pos += n;
+                }
+                _ => return Err(Error::Read),
+            };
+
+            debug!("Buffer contents: '{:?}'", LossyStr(&self.buf[..self.pos]));
+
+            while self.pos > 0 {
+                let (res, swallowed) = match self.digester.digest(&self.buf[..self.pos]) {
+                    (DigestResult::None, swallowed) => {
+                        if swallowed > 0 {
+                            debug!(
+                                "Received echo or whitespace ({}/{}): {:?}",
+                                swallowed,
+                                self.pos,
+                                LossyStr(&self.buf[..swallowed])
+                            );
+                        }
+                        (None, swallowed)
+                    }
+                    (DigestResult::Urc(urc_line), swallowed) => {
+                        warn!("Unable to handle URC! Ignoring: {:?}", LossyStr(urc_line));
+                        (None, swallowed)
+                    }
+                    (DigestResult::Prompt(prompt), swallowed) => {
+                        debug!("Received prompt ({}/{})", swallowed, self.pos);
+
+                        (Some(Response::Prompt(prompt)), swallowed)
+                    }
+                    (DigestResult::Response(resp), swallowed) => {
+                        match &resp {
+                            Ok(r) => {
+                                if r.is_empty() {
+                                    debug!("Received OK ({}/{})", swallowed, self.pos)
+                                } else {
+                                    debug!(
+                                        "Received response ({}/{}): {:?}",
+                                        swallowed,
+                                        self.pos,
+                                        LossyStr(r)
+                                    );
+                                }
+                            }
+                            Err(e) => {
+                                warn!(
+                                    "Received error response ({}/{}): {:?}",
+                                    swallowed, self.pos, e
+                                );
+                            }
+                        }
+
+                        (Some(resp.into()), swallowed)
+                    }
+                };
+
+                if swallowed == 0 {
+                    break;
+                }
+
+                self.consume(swallowed);
+
+                if let Some(resp) = res {
+                    return Ok(resp);
+                }
+            }
+        }
+    }
+
+    fn consume(&mut self, amt: usize) {
+        self.buf.copy_within(amt..self.pos, 0);
+        self.pos -= amt;
+    }
+
+    fn start_cooldown_timer(&mut self) {
+        self.cooldown_timer = Some(Timer::after(self.config.cmd_cooldown));
+    }
+
+    async fn wait_cooldown_timer(&mut self) {
+        if let Some(cooldown) = self.cooldown_timer.take() {
+            cooldown.await
+        }
+    }
+}
+
+impl<RW: Read + Write, D: Digester> AtatClient for SimpleClient<'_, RW, D> {
+    async fn send<Cmd: AtatCmd>(&mut self, cmd: &Cmd) -> Result<Cmd::Response, Error> {
+        let len = cmd.write(&mut self.buf);
+
+        self.send_request(len).await?;
+        if !Cmd::EXPECTS_RESPONSE_CODE {
+            cmd.parse(Ok(&[]))
+        } else {
+            let response = embassy_time::with_timeout(
+                Duration::from_millis(Cmd::MAX_TIMEOUT_MS.into()),
+                self.wait_response(),
+            )
+            .await
+            .map_err(|_| Error::Timeout)??;
+
+            cmd.parse((&response).into())
+        }
+    }
+}