Input, Driver: Make error messages more idiomatic (#74)

Cargo.toml

@@ -127,6 +127,7 @@ features = ["v4"]
 [dependencies.xsalsa20poly1305]
 optional = true
 version = "0.7"
+features = ["std"]
 
 [dev-dependencies]
 criterion = "0.3"

src/driver/connection/error.rs

@@ -6,7 +6,7 @@ use crate::{
 };
 use flume::SendError;
 use serde_json::Error as JsonError;
-use std::{error::Error as ErrorTrait, fmt, io::Error as IoError};
+use std::{error::Error as StdError, fmt, io::Error as IoError};
 use xsalsa20poly1305::aead::Error as CryptoError;
 
 /// Errors encountered while connecting to a Discord voice server over the driver.
@@ -84,27 +84,43 @@ impl From<WsError> for Error {
 
 impl fmt::Display for Error {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "Failed to connect to Discord RTP server: ")?;
+        write!(f, "failed to connect to Discord RTP server: ")?;
         use Error::*;
         match self {
-            AttemptDiscarded => write!(f, "connection attempt was aborted/discarded."),
-            Crypto(c) => write!(f, "cryptography error {}.", c),
-            CryptoModeInvalid => write!(f, "server changed negotiated encryption mode."),
-            CryptoModeUnavailable => write!(f, "server did not offer chosen encryption mode."),
-            EndpointUrl => write!(f, "endpoint URL received from gateway was invalid."),
-            ExpectedHandshake => write!(f, "voice initialisation protocol was violated."),
-            IllegalDiscoveryResponse =>
-                write!(f, "IP discovery/NAT punching response was invalid."),
-            IllegalIp => write!(f, "IP discovery/NAT punching response had bad IP value."),
-            Io(i) => write!(f, "I/O failure ({}).", i),
-            Json(j) => write!(f, "JSON (de)serialization issue ({}).", j),
-            InterconnectFailure(r) => write!(f, "failed to contact other task ({:?})", r),
-            Ws(w) => write!(f, "websocket issue ({:?}).", w),
+            AttemptDiscarded => write!(f, "connection attempt was aborted/discarded"),
+            Crypto(e) => e.fmt(f),
+            CryptoModeInvalid => write!(f, "server changed negotiated encryption mode"),
+            CryptoModeUnavailable => write!(f, "server did not offer chosen encryption mode"),
+            EndpointUrl => write!(f, "endpoint URL received from gateway was invalid"),
+            ExpectedHandshake => write!(f, "voice initialisation protocol was violated"),
+            IllegalDiscoveryResponse => write!(f, "IP discovery/NAT punching response was invalid"),
+            IllegalIp => write!(f, "IP discovery/NAT punching response had bad IP value"),
+            Io(e) => e.fmt(f),
+            Json(e) => e.fmt(f),
+            InterconnectFailure(e) => write!(f, "failed to contact other task ({:?})", e),
+            Ws(e) => write!(f, "websocket issue ({:?}).", e),
         }
     }
 }
 
-impl ErrorTrait for Error {}
+impl StdError for Error {
+    fn source(&self) -> Option<&(dyn StdError + 'static)> {
+        match self {
+            Error::AttemptDiscarded => None,
+            Error::Crypto(e) => e.source(),
+            Error::CryptoModeInvalid => None,
+            Error::CryptoModeUnavailable => None,
+            Error::EndpointUrl => None,
+            Error::ExpectedHandshake => None,
+            Error::IllegalDiscoveryResponse => None,
+            Error::IllegalIp => None,
+            Error::Io(e) => e.source(),
+            Error::Json(e) => e.source(),
+            Error::InterconnectFailure(_) => None,
+            Error::Ws(_) => None,
+        }
+    }
+}
 
 /// Convenience type for Discord voice/driver connection error handling.
 pub type Result<T> = std::result::Result<T, Error>;

src/error.rs

@@ -78,24 +78,39 @@ impl JoinError {
 #[cfg(feature = "gateway-core")]
 impl fmt::Display for JoinError {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "Failed to Join Voice channel: ")?;
+        write!(f, "failed to join voice channel: ")?;
         match self {
-            JoinError::Dropped => write!(f, "request was cancelled/dropped."),
-            JoinError::NoSender => write!(f, "no gateway destination."),
-            JoinError::NoCall => write!(f, "tried to leave a non-existent call."),
-            JoinError::TimedOut => write!(f, "gateway response from Discord timed out."),
+            JoinError::Dropped => write!(f, "request was cancelled/dropped"),
+            JoinError::NoSender => write!(f, "no gateway destination"),
+            JoinError::NoCall => write!(f, "tried to leave a non-existent call"),
+            JoinError::TimedOut => write!(f, "gateway response from Discord timed out"),
             #[cfg(feature = "driver-core")]
-            JoinError::Driver(t) => write!(f, "internal driver error {}.", t),
+            JoinError::Driver(_) => write!(f, "establishing connection failed"),
             #[cfg(feature = "serenity")]
-            JoinError::Serenity(t) => write!(f, "serenity failure {}.", t),
+            JoinError::Serenity(e) => e.fmt(f),
             #[cfg(feature = "twilight")]
-            JoinError::Twilight(t) => write!(f, "twilight failure {}.", t),
+            JoinError::Twilight(e) => e.fmt(f),
         }
     }
 }
 
 #[cfg(feature = "gateway-core")]
-impl Error for JoinError {}
+impl Error for JoinError {
+    fn source(&self) -> Option<&(dyn Error + 'static)> {
+        match self {
+            JoinError::Dropped => None,
+            JoinError::NoSender => None,
+            JoinError::NoCall => None,
+            JoinError::TimedOut => None,
+            #[cfg(feature = "driver-core")]
+            JoinError::Driver(e) => Some(e),
+            #[cfg(feature = "serenity")]
+            JoinError::Serenity(e) => e.source(),
+            #[cfg(feature = "twilight")]
+            JoinError::Twilight(e) => e.source(),
+        }
+    }
+}
 
 #[cfg(all(feature = "serenity", feature = "gateway-core"))]
 impl From<TrySendError<InterMessage>> for JoinError {

src/input/error.rs

@@ -72,20 +72,20 @@ impl From<OpusError> for Error {
 impl fmt::Display for Error {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
-            Error::Dca(e) => write!(f, "{}", e),
-            Error::Io(e) => write!(f, "{}", e),
+            Error::Dca(_) => write!(f, "opening file DCA failed"),
+            Error::Io(e) => e.fmt(f),
             Error::Json {
-                error,
+                error: _,
                 parsed_text: _,
-            } => write!(f, "{}", error),
-            Error::Opus(e) => write!(f, "{}", e),
-            Error::Metadata => write!(f, "Failed to extract metadata"),
-            Error::Stdout => write!(f, "Failed to create stdout"),
-            Error::Streams => write!(f, "Error while checking if path is stereo"),
-            Error::Streamcatcher(e) => write!(f, "{}", e),
-            Error::YouTubeDlProcessing(_) => write!(f, "Processing JSON from youtube-dl failed"),
-            Error::YouTubeDlRun(_) => write!(f, "youtube-dl encountered an error"),
-            Error::YouTubeDlUrl(_) => write!(f, "Missing url field in JSON"),
+            } => write!(f, "parsing JSON failed"),
+            Error::Opus(e) => e.fmt(f),
+            Error::Metadata => write!(f, "extracting metadata failed"),
+            Error::Stdout => write!(f, "creating stdout failed"),
+            Error::Streams => write!(f, "checking if path is stereo failed"),
+            Error::Streamcatcher(_) => write!(f, "invalid config for cached input"),
+            Error::YouTubeDlProcessing(_) => write!(f, "youtube-dl returned invalid JSON"),
+            Error::YouTubeDlRun(o) => write!(f, "youtube-dl encontered an error: {:?}", o),
+            Error::YouTubeDlUrl(_) => write!(f, "missing youtube-dl url"),
         }
     }
 }
@@ -94,12 +94,12 @@ impl StdError for Error {
     fn source(&self) -> Option<&(dyn StdError + 'static)> {
         match self {
             Error::Dca(e) => Some(e),
-            Error::Io(e) => Some(e),
+            Error::Io(e) => e.source(),
             Error::Json {
                 error,
                 parsed_text: _,
             } => Some(error),
-            Error::Opus(e) => Some(e),
+            Error::Opus(e) => e.source(),
             Error::Metadata => None,
             Error::Stdout => None,
             Error::Streams => None,
@@ -132,23 +132,23 @@ pub enum DcaError {
 impl fmt::Display for DcaError {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
-            DcaError::IoError(e) => write!(f, "{}", e),
-            DcaError::InvalidHeader => write!(f, "Invalid DCA JSON header"),
-            DcaError::InvalidMetadata(e) => write!(f, "{}", e),
-            DcaError::InvalidSize(e) => write!(f, "Invalid metadata block size: {}", e),
-            DcaError::Opus(e) => write!(f, "{}", e),
+            DcaError::IoError(e) => e.fmt(f),
+            DcaError::InvalidHeader => write!(f, "invalid header"),
+            DcaError::InvalidMetadata(_) => write!(f, "invalid metadata"),
+            DcaError::InvalidSize(e) => write!(f, "invalid metadata block size: {}", e),
+            DcaError::Opus(e) => e.fmt(f),
         }
     }
 }
 
 impl StdError for DcaError {
     fn source(&self) -> Option<&(dyn StdError + 'static)> {
         match self {
-            DcaError::IoError(e) => Some(e),
+            DcaError::IoError(e) => e.source(),
             DcaError::InvalidHeader => None,
             DcaError::InvalidMetadata(e) => Some(e),
             DcaError::InvalidSize(_) => None,
-            DcaError::Opus(e) => Some(e),
+            DcaError::Opus(e) => e.source(),
         }
     }
 }

src/tracks/error.rs

@@ -21,12 +21,12 @@ pub enum TrackError {
 
 impl fmt::Display for TrackError {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        write!(f, "Failed to operate on track (handle): ")?;
+        write!(f, "failed to operate on track (handle): ")?;
         match self {
-            TrackError::Finished => write!(f, "track ended."),
+            TrackError::Finished => write!(f, "track ended"),
             TrackError::InvalidTrackEvent =>
-                write!(f, "given event listener can't be fired on a track."),
-            TrackError::SeekUnsupported => write!(f, "track did not support seeking."),
+                write!(f, "given event listener can't be fired on a track"),
+            TrackError::SeekUnsupported => write!(f, "track did not support seeking"),
         }
     }
 }