Improve pipe backend

* Implement stop
* Better error handling

playback/src/audio_backend/pipe.rs

@@ -2,9 +2,38 @@ use super::{Open, Sink, SinkAsBytes, SinkError, SinkResult};
 use crate::config::AudioFormat;
 use crate::convert::Converter;
 use crate::decoder::AudioPacket;
+
 use std::fs::OpenOptions;
 use std::io::{self, Write};
 use std::process::exit;
+use thiserror::Error;
+
+#[derive(Debug, Error)]
+enum StdoutError {
+    #[error("<StdoutSink> {0}")]
+    OnWrite(std::io::Error),
+
+    #[error("<StdoutSink> File Path {file} Can Not be Opened and/or Created, {e}")]
+    OpenFailure { file: String, e: std::io::Error },
+
+    #[error("<StdoutSink> Failed to Flush the Output Stream, {0}")]
+    FlushFailure(std::io::Error),
+
+    #[error("<StdoutSink> The Output Stream is None")]
+    NoOutput,
+}
+
+impl From<StdoutError> for SinkError {
+    fn from(e: StdoutError) -> SinkError {
+        use StdoutError::*;
+        let es = e.to_string();
+        match e {
+            FlushFailure(_) | OnWrite(_) => SinkError::OnWrite(es),
+            OpenFailure { .. } => SinkError::ConnectionRefused(es),
+            NoOutput => SinkError::NotConnected(es),
+        }
+    }
+}
 
 pub struct StdoutSink {
     output: Option<Box<dyn Write>>,
@@ -15,13 +44,12 @@ pub struct StdoutSink {
 impl Open for StdoutSink {
     fn open(file: Option<String>, format: AudioFormat) -> Self {
         if let Some("?") = file.as_deref() {
-            info!("Usage:");
+            println!("\nUsage:\n\nOutput to stdout:\n\n\t--backend pipe\n\nOutput to file:\n\n\t--backend pipe --device {{filename}}\n");
-            println!("  Output to stdout: --backend pipe");
-            println!("  Output to file:   --backend pipe --device {{filename}}");
             exit(0);
         }
 
-        info!("Using pipe sink with format: {:?}", format);
+        info!("Using StdoutSink (pipe) with format: {:?}", format);
+
         Self {
             output: None,
             file,
@@ -32,21 +60,31 @@ impl Open for StdoutSink {
 
 impl Sink for StdoutSink {
     fn start(&mut self) -> SinkResult<()> {
-        if self.output.is_none() {
+        self.output.get_or_insert({
-            let output: Box<dyn Write> = match self.file.as_deref() {
+            match self.file.as_deref() {
-                Some(file) => {
+                Some(file) => Box::new(
-                    let open_op = OpenOptions::new()
+                    OpenOptions::new()
                         .write(true)
                         .create(true)
                         .open(file)
-                        .map_err(|e| SinkError::ConnectionRefused(e.to_string()))?;
+                        .map_err(|e| StdoutError::OpenFailure {
-                    Box::new(open_op)
+                            file: file.to_string(),
-                }
+                            e,
+                        })?,
+                ),
                 None => Box::new(io::stdout()),
-            };
-
-            self.output = Some(output);
             }
+        });
+
+        Ok(())
+    }
+
+    fn stop(&mut self) -> SinkResult<()> {
+        self.output
+            .take()
+            .ok_or(StdoutError::NoOutput)?
+            .flush()
+            .map_err(StdoutError::FlushFailure)?;
 
         Ok(())
     }
@@ -56,19 +94,11 @@ impl Sink for StdoutSink {
 
 impl SinkAsBytes for StdoutSink {
     fn write_bytes(&mut self, data: &[u8]) -> SinkResult<()> {
-        match self.output.as_deref_mut() {
+        self.output
-            Some(output) => {
+            .as_deref_mut()
-                output
+            .ok_or(StdoutError::NoOutput)?
             .write_all(data)
-                    .map_err(|e| SinkError::OnWrite(e.to_string()))?;
+            .map_err(StdoutError::OnWrite)?;
-                output
-                    .flush()
-                    .map_err(|e| SinkError::OnWrite(e.to_string()))?;
-            }
-            None => {
-                return Err(SinkError::NotConnected("Output is None".to_string()));
-            }
-        }
 
         Ok(())
     }