read_line now returns String instead of Result<string>

maybe a worse interface than before ... will be revisited

src/modem.rs

@@ -19,7 +19,7 @@ pub struct Modem<UART: serial::Uart> {
 pub enum ModemError {
     CommandError(String),
     SetupError(String),
-    ReadError,
+    SendDataError,
     TimeoutError,
 }
 
@@ -41,6 +41,11 @@ impl<UART: serial::Uart> IterableRx<UART> {
         self.timeout = timeout;
         self
     }
+
+    fn clear(&mut self) -> () {
+        println!("clearing serial rx");
+        self.reset(Duration::from_millis(500)).for_each(drop);
+    }
 }
 
 impl<UART: serial::Uart> Iterator for IterableRx<UART> {
@@ -114,23 +119,11 @@ impl<UART: serial::Uart> Modem<UART> {
 
     /// Reads a whole line (that ends with \\n) within the given `timeout` passed on input.
     ///
-    fn read_line(&mut self, timeout: Duration) -> Result<String> {
-        let line: String = self.rx.reset(timeout)
+    fn read_line(&mut self, timeout: Duration) -> String {
+        self.rx.reset(timeout)
             .map(|b| char::from(b))
             .take_while(|c| *c != '\n')
-            .collect();
-
-        // A necessary check because the actual timeout is in the Iterator implementation. The
-        // iterator exits when the returned Item is None, which happens when there's no data in
-        // the serial port and the timeout is breached.
-        //
-        // This check here is tested on sim800l and works only because the modem has \r\n as CRLF.
-        if line.ends_with("\r") {
-            Ok(format!("{}\n", line))
-        }
-        else {
-            Err(ModemError::ReadError)
-        }
+            .collect()
     }
 
     /// Reads the serial RX until a \\n char is encoutered, or a timeout is reached. The timeout is
@@ -145,8 +138,8 @@ impl<UART: serial::Uart> Modem<UART> {
         let match_text: String = contains.unwrap_or("\n".to_string());
 
         loop {
-            let rdln = self.read_line(timeout.saturating_sub(start.elapsed()));
-            if let Ok(line) = rdln {
+            let line = self.read_line(timeout.saturating_sub(start.elapsed()));
+            if line != "" {
                 println!("Read {} bytes from serial ({})", line.len(), line);
                 response.push_str(&line);
                 if line.contains("ERROR") || line.contains(&match_text) {
@@ -156,7 +149,7 @@ impl<UART: serial::Uart> Modem<UART> {
                 }
             } else {
                 println!("-----------------------------------------------------------");
-                println!("Read line {:?}", rdln);
+                println!("got empty line from read_line :(");
                 break Err(ModemError::TimeoutError)
             }
         }
@@ -168,39 +161,42 @@ impl<UART: serial::Uart> Modem<UART> {
         Ok(())
     }
 
-    fn send_bytes(&mut self, payload: &[u8]) -> Result<()> {
+    fn send_bytes(&mut self, payload: &[u8], eos: char) -> Result<()> {
         for b in payload.iter() {
             self.send(*b)?;
         }
-        self.send('\r' as u8)?;
+        self.send(eos as u8)?;
         Ok(())
     }
 
     fn send_command(&mut self, cmd: Command) -> Result<String> {
         println!("-----------------------------------------------------------");
         println!("Sending {} ...", cmd.text);
-        let _ = self.send_bytes(cmd.text.as_bytes())?;
+        let _ = self.send_bytes(cmd.text.as_bytes(), '\r')?;
         self.read_response(cmd.contains, cmd.timeout)
     }
 
     fn send_data(&mut self, payload: &str) -> Result<String> {
-        let _ = self.send_bytes("AT+CIPSEND".as_bytes())?;
-        for c in self.rx.reset(Duration::from_millis(2000)).map(char::from) {
-            println!("{}", c);
-            if c == '>' {
-                for b in payload.as_bytes() {
-                    self.send(*b)?;
-                }
-                self.send(26)?;
-                return self.read_response(Some("DATA ACCEPT".to_string()), Duration::from_millis(3000));
-            }
+        self.rx.clear();
+        let _ = self.send_bytes("AT+CIPSEND".as_bytes(), '\r')?;
+        let send_request: String = self.rx.reset(Duration::from_millis(3000))
+            .map(char::from)
+            .take_while(|c| *c != '>').collect();
+
+        if send_request == "" {
+            return Err(ModemError::SendDataError);
         }
-        self.send_command(Command {
+
+        self.send_bytes(payload.as_bytes(), 26 as char)?; // 26_u8 = Ctrl+z - to end sending data
+        let _ = self.read_response(Some("DATA ACCEPT".to_string()), Duration::from_millis(3000));
+
+        self.rx.clear();
+        let res = self.send_command(Command {
             text: "AT+CIPACK".to_string(),
             contains: Some("OK".to_string()),
             timeout: Duration::from_millis(3000),
         })?;
-        Ok("OK".to_string())
+        Ok(res)
     }
 
     pub fn get_ip_addr(&mut self) -> Result<String> {
@@ -223,10 +219,6 @@ impl<UART: serial::Uart> Modem<UART> {
         Ok(())
     }
 
-    pub fn probe(&mut self)-> Result<String> {
-        self.send_command(Command::probe())
-    }
-
     pub fn is_gprs_attached(&mut self)-> Result<bool> {
         let res = self.send_command(Command::is_gprs_attached())?;
         Ok(res.contains("+CGATT: 1"))