use Results and not unwraps (#10)

* use `Result`s and not unwraps

* fix test assertion

wakey-wake/src/main.rs

@@ -7,11 +7,12 @@ struct CmdArgs {
     #[clap(short, long)]
     mac: Option<String>,
 }
-fn main() {
+
+fn main() -> wakey::Result<()> {
     let args = CmdArgs::parse();
     if let Some(m) = args.mac {
         let sep = m.chars().find(|ch| *ch == ':' || *ch == '-').unwrap_or('/');
-        let wol = wakey::WolPacket::from_string(&m, sep);
+        let wol = wakey::WolPacket::from_string(&m, sep)?;
         if wol.send_magic().is_ok() {
             println!("sent the magic packet.");
         } else {
@@ -20,4 +21,6 @@ fn main() {
     } else {
         println!("give mac address to wake up");
     }
+
+    Ok(())
 }

wakey/src/lib.rs

@@ -1,7 +1,7 @@
 //! Library for managing Wake-on-LAN packets.
 //! # Example
 //! ```
-//! let wol = wakey::WolPacket::from_string("01:02:03:04:05:06", ':');
+//! let wol = wakey::WolPacket::from_string("01:02:03:04:05:06", ':').unwrap();
 //! if wol.send_magic().is_ok() {
 //!     println!("Sent the magic packet!");
 //! } else {
@@ -9,8 +9,9 @@
 //! }
 //! ```
 
-use std::iter;
+use std::error::Error;
 use std::net::{SocketAddr, ToSocketAddrs, UdpSocket};
+use std::{fmt, iter};
 
 use arrayvec::ArrayVec;
 
@@ -20,6 +21,41 @@ const HEADER: [u8; 6] = [0xFF; 6];
 const PACKET_LEN: usize = HEADER.len() + MAC_SIZE * MAC_PER_MAGIC;
 
 type Packet = ArrayVec<u8, PACKET_LEN>;
+type Mac = ArrayVec<u8, MAC_SIZE>;
+
+/// Wrapper `Result` for the module errors.
+pub type Result<T> = std::result::Result<T, WakeyError>;
+
+/// Wrapper Error for fiascoes occuring in this module.
+#[derive(Debug)]
+pub enum WakeyError {
+    /// The provided MAC address has invalid length.
+    InvalidMacLength,
+    /// The provided MAC address has invalid format.
+    InvalidMacFormat,
+    /// There was an error sending the WoL packet.
+    SendFailure(std::io::Error),
+}
+
+impl Error for WakeyError {}
+
+impl fmt::Display for WakeyError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self {
+            WakeyError::InvalidMacLength => {
+                write!(f, "Invalid MAC address length")
+            }
+            WakeyError::InvalidMacFormat => write!(f, "Invalid MAC address format"),
+            WakeyError::SendFailure(e) => write!(f, "Couldn't send WoL packet: {e}"),
+        }
+    }
+}
+
+impl From<std::io::Error> for WakeyError {
+    fn from(error: std::io::Error) -> Self {
+        WakeyError::SendFailure(error)
+    }
+}
 
 /// Wake-on-LAN packet
 #[derive(Debug, Clone, PartialEq, Eq)]
@@ -34,10 +70,10 @@ impl WolPacket {
     /// ```
     /// let wol = wakey::WolPacket::from_bytes(&vec![0x00, 0x01, 0x02, 0x03, 0x04, 0x05]);
     /// ```
-    pub fn from_bytes(mac: &[u8]) -> WolPacket {
+    pub fn from_bytes(mac: &[u8]) -> Result<WolPacket> {
-        WolPacket {
+        Ok(WolPacket {
-            packet: WolPacket::create_packet_bytes(mac),
+            packet: WolPacket::create_packet_bytes(mac)?,
-        }
+        })
     }
 
     /// Creates WOL packet from string MAC representation (e.x. 00:01:02:03:04:05)
@@ -47,8 +83,8 @@ impl WolPacket {
     /// ```
     /// # Panic
     ///  Panics when input MAC is invalid (i.e. contains non-byte characters)
-    pub fn from_string<T: AsRef<str>>(data: T, sep: char) -> WolPacket {
+    pub fn from_string<T: AsRef<str>>(data: T, sep: char) -> Result<WolPacket> {
-        WolPacket::from_bytes(&WolPacket::mac_to_byte(data, sep))
+        WolPacket::from_bytes(&WolPacket::mac_to_byte(data, sep)?)
     }
 
     /// Broadcasts the magic packet from / to default address
@@ -56,10 +92,10 @@ impl WolPacket {
     /// Destination 255.255.255.255:9
     /// # Example
     /// ```
-    /// let wol = wakey::WolPacket::from_bytes(&vec![0x00, 0x01, 0x02, 0x03, 0x04, 0x05]);
+    /// let wol = wakey::WolPacket::from_bytes(&vec![0x00, 0x01, 0x02, 0x03, 0x04, 0x05]).unwrap();
     /// wol.send_magic();
     /// ```
-    pub fn send_magic(&self) -> std::io::Result<()> {
+    pub fn send_magic(&self) -> Result<()> {
         self.send_magic_to(
             SocketAddr::from(([0, 0, 0, 0], 0)),
             SocketAddr::from(([255, 255, 255, 255], 9)),
@@ -70,12 +106,12 @@ impl WolPacket {
     /// # Example
     /// ```
     /// use std::net::SocketAddr;
-    /// let wol = wakey::WolPacket::from_bytes(&vec![0x00, 0x01, 0x02, 0x03, 0x04, 0x05]);
+    /// let wol = wakey::WolPacket::from_bytes(&vec![0x00, 0x01, 0x02, 0x03, 0x04, 0x05]).unwrap();
     /// let src = SocketAddr::from(([0,0,0,0], 0));
     /// let dst = SocketAddr::from(([255,255,255,255], 9));
     /// wol.send_magic_to(src, dst);
     /// ```
-    pub fn send_magic_to<A: ToSocketAddrs>(&self, src: A, dst: A) -> std::io::Result<()> {
+    pub fn send_magic_to<A: ToSocketAddrs>(&self, src: A, dst: A) -> Result<()> {
         let udp_sock = UdpSocket::bind(src)?;
         udp_sock.set_broadcast(true)?;
         udp_sock.send_to(&self.packet, dst)?;
@@ -91,16 +127,24 @@ impl WolPacket {
     /// Converts string representation of MAC address (e.x. 00:01:02:03:04:05) to raw bytes.
     /// # Panic
     /// Panics when input MAC is invalid (i.e. contains non-byte characters)
-    fn mac_to_byte<T: AsRef<str>>(data: T, sep: char) -> ArrayVec<u8, MAC_SIZE> {
+    fn mac_to_byte<T: AsRef<str>>(data: T, sep: char) -> Result<Mac> {
+        // hex-encoded bytes * 2 plus separators
+        if data.as_ref().len() != MAC_SIZE * 3 - 1 {
+            return Err(WakeyError::InvalidMacLength);
+        }
+
         let bytes = data
             .as_ref()
             .split(sep)
-            .flat_map(|x| hex::decode(x).expect("Invalid mac!"))
+            .map(|x| hex::decode(x).map_err(|_| WakeyError::InvalidMacFormat))
-            .collect::<ArrayVec<u8, MAC_SIZE>>();
+            .collect::<Result<ArrayVec<_, MAC_SIZE>>>()?
+            .into_iter()
+            .flatten()
+            .collect::<Mac>();
 
         debug_assert_eq!(MAC_SIZE, bytes.len());
 
-        bytes
+        Ok(bytes)
     }
 
     /// Extends the MAC address to fill the magic packet
@@ -117,7 +161,10 @@ impl WolPacket {
     }
 
     /// Creates bytes of the magic packet from MAC address
-    fn create_packet_bytes(mac: &[u8]) -> Packet {
+    fn create_packet_bytes(mac: &[u8]) -> Result<Packet> {
+        if mac.len() != MAC_SIZE {
+            return Err(WakeyError::InvalidMacLength);
+        }
         let mut packet = Packet::new();
 
         packet.extend(HEADER);
@@ -125,7 +172,7 @@ impl WolPacket {
 
         debug_assert_eq!(PACKET_LEN, packet.len());
 
-        packet
+        Ok(packet)
     }
 }
 
@@ -163,42 +210,50 @@ mod tests {
         let result = WolPacket::mac_to_byte(mac, ':');
 
         assert_eq!(
-            result.into_inner().unwrap(),
+            result.unwrap().into_inner().unwrap(),
             [0x01, 0x02, 0x03, 0x04, 0x05, 0x06]
         );
     }
 
     #[test]
-    #[should_panic]
     fn mac_to_byte_invalid_chars_test() {
         let mac = "ZZ:02:03:04:05:06";
-        WolPacket::mac_to_byte(mac, ':');
+        assert!(matches!(
+            WolPacket::mac_to_byte(mac, ':'),
+            Err(WakeyError::InvalidMacFormat)
+        ));
     }
 
     #[test]
-    #[should_panic]
     fn mac_to_byte_invalid_separator_test() {
         let mac = "01002:03:04:05:06";
-        WolPacket::mac_to_byte(mac, ':');
+        assert!(matches!(
+            WolPacket::mac_to_byte(mac, ':'),
+            Err(WakeyError::InvalidMacFormat)
+        ));
     }
 
     #[test]
-    #[should_panic]
     fn mac_to_byte_mac_too_long_test() {
         let mac = "01:02:03:04:05:06:07";
-        WolPacket::mac_to_byte(mac, ':');
+        assert!(matches!(
+            WolPacket::mac_to_byte(mac, ':'),
+            Err(WakeyError::InvalidMacLength)
+        ));
     }
 
     #[test]
-    #[should_panic]
     fn mac_to_byte_mac_too_short_test() {
         let mac = "01:02:03:04:05";
-        WolPacket::mac_to_byte(mac, ':');
+        assert!(matches!(
+            WolPacket::mac_to_byte(mac, ':'),
+            Err(WakeyError::InvalidMacLength)
+        ));
     }
 
     #[test]
     fn create_packet_bytes_test() {
-        let bytes = WolPacket::create_packet_bytes(&[0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF]);
+        let bytes = WolPacket::create_packet_bytes(&[0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF]).unwrap();
 
         assert_eq!(bytes.len(), MAC_SIZE * MAC_PER_MAGIC + HEADER.len());
         assert!(bytes.iter().all(|&x| x == 0xFF));
@@ -207,7 +262,7 @@ mod tests {
     #[test]
     fn create_wol_packet() {
         let mac = vec![0x00, 0x01, 0x02, 0x03, 0x04, 0x05];
-        let wol = WolPacket::from_bytes(&mac);
+        let wol = WolPacket::from_bytes(&mac).unwrap();
         let packet = wol.into_inner();
 
         assert_eq!(packet.len(), PACKET_LEN);