async encoding

src/download.rs

@@ -1,6 +1,6 @@
 use std::fmt::Write;
 use std::path::PathBuf;
-use std::sync::Arc;
+use std::time::Duration;
 
 use anyhow::Result;
 use futures::StreamExt;
@@ -100,6 +100,7 @@ impl Downloader {
         );
 
         let pb = self.progress_bar.add(ProgressBar::new(file_size as u64));
+        pb.enable_steady_tick(Duration::from_millis(100));
         pb.set_style(ProgressStyle::with_template("{spinner:.green} {msg} [{elapsed_precise}] [{wide_bar:.cyan/blue}] {bytes}/{total_bytes} ({eta})")?
             .with_key("eta", |state: &ProgressState, w: &mut dyn Write| write!(w, "{:.1}s", state.eta().as_secs_f64()).unwrap())
             .progress_chars("#>-"));
@@ -122,24 +123,23 @@ impl Downloader {
                     samples.append(&mut content);
                 }
                 SinkEvent::Finished => {
-                    pb.finish_with_message(format!("Downloaded {}", &file_name));
+                    tracing::info!("Finished downloading track: {:?}", file_name);
+                    break;
                 }
             }
         }
 
-        tracing::info!("Downloaded track: {:?}", file_name);
-
-        let samples = Samples::new(samples, 44100, 2, 16);
-
-        let format = options.format.clone();
-        tokio_rayon::spawn(move || {
         tracing::info!("Encoding track: {:?}", file_name);
-            let encoder = crate::encoder::get_encoder(format).unwrap();
-            let stream = encoder.encode(samples).unwrap();
-            tracing::info!("Writing track: {:?} to file: {}", file_name, &path);
-            stream.write_to_file(&path).unwrap();
-        }).await;
+        pb.set_message(format!("Encoding {}", &file_name));
+        let samples = Samples::new(samples, 44100, 2, 16);
+        let encoder = crate::encoder::get_encoder(options.format)?;
+        let stream = encoder.encode(samples).await?;
 
+        pb.set_message(format!("Writing {}", &file_name));
+        tracing::info!("Writing track: {:?} to file: {}", file_name, &path);
+        stream.write_to_file(&path).await?;
+
+        pb.finish_with_message(format!("Downloaded {}", &file_name));
         Ok(())
     }
 

src/encoder/flac.rs

@@ -1,28 +1,24 @@
 use flacenc::bitsink::ByteSink;
 use flacenc::component::BitRepr;
-use flacenc::error::Verified;
 use flacenc::error::Verify;
 
+use super::execute_with_result;
 use super::EncodedStream;
 use super::Encoder;
 use super::Samples;
 
 #[derive(Debug)]
-pub struct FlacEncoder {
-    config: Verified<flacenc::config::Encoder>,
-}
+pub struct FlacEncoder;
 
 impl FlacEncoder {
     pub fn new() -> anyhow::Result<Self> {
-        let config = flacenc::config::Encoder::default()
-            .into_verified()
-            .map_err(|e| anyhow::anyhow!("Failed to verify encoder config: {:?}", e))?;
-        Ok(FlacEncoder { config })
+        Ok(Self)
     }
 }
 
+#[async_trait::async_trait]
 impl Encoder for FlacEncoder {
-    fn encode(&self, samples: Samples) -> anyhow::Result<EncodedStream> {
+    async fn encode(&self, samples: Samples) -> anyhow::Result<EncodedStream> {
         let source = flacenc::source::MemSource::from_samples(
             &samples.samples,
             samples.channels as usize,
@@ -30,8 +26,19 @@ impl Encoder for FlacEncoder {
             samples.sample_rate as usize,
         );
 
-        let flac_stream =
-            flacenc::encode_with_fixed_block_size(&self.config, source, self.config.block_size)
+        let config = flacenc::config::Encoder::default()
+            .into_verified()
+            .map_err(|e| anyhow::anyhow!("Failed to verify encoder config: {:?}", e))?;
+
+        let (tx, rx) = tokio::sync::oneshot::channel();
+
+        rayon::spawn(execute_with_result(
+            move || {
+                let flac_stream = flacenc::encode_with_fixed_block_size(
+                    &config,
+                    source,
+                    config.block_size,
+                )
                 .map_err(|e| anyhow::anyhow!("Failed to encode flac: {:?}", e))?;
 
                 let mut byte_sink = ByteSink::new();
@@ -39,6 +46,13 @@ impl Encoder for FlacEncoder {
                     .write(&mut byte_sink)
                     .map_err(|e| anyhow::anyhow!("Failed to write flac stream: {:?}", e))?;
 
-        Ok(EncodedStream::new(byte_sink.into_inner()))
+                Ok(byte_sink.into_inner())
+            },
+            tx,
+        ));
+
+        let byte_sink: Vec<u8> = rx.await??;
+
+        Ok(EncodedStream::new(byte_sink))
     }
 }

src/encoder/mod.rs

@@ -2,10 +2,11 @@ mod flac;
 #[cfg(feature = "mp3")]
 mod mp3;
 
-use std::str::FromStr;
+use std::{path::Path, str::FromStr};
 
 use anyhow::Result;
 use lazy_static::lazy_static;
+use tokio::sync::oneshot::Sender;
 
 #[derive(Debug, Clone, Copy, Eq, PartialEq, Hash)]
 pub enum Format {
@@ -54,8 +55,9 @@ pub fn get_encoder(format: Format) -> anyhow::Result<&'static Box<dyn Encoder +
     }
 }
 
+#[async_trait::async_trait]
 pub trait Encoder {
-    fn encode(&self, samples: Samples) -> Result<EncodedStream>;
+    async fn encode(&self, samples: Samples) -> Result<EncodedStream>;
 }
 
 pub struct Samples {
@@ -85,15 +87,27 @@ impl EncodedStream {
         EncodedStream { stream }
     }
 
-    pub fn write_to_file<P: std::convert::AsRef<std::path::Path>>(&self, path: P) -> Result<()> {
+    pub async fn write_to_file<P: AsRef<Path>>(&self, path: P) -> Result<()> {
         if !path.as_ref().exists() {
-            std::fs::create_dir_all(
+            tokio::fs::create_dir_all(
                 path.as_ref()
                     .parent()
                     .ok_or(anyhow::anyhow!("Could not create path"))?,
-            )?;
+            ).await?;
         }
-        std::fs::write(path, &self.stream)?;
+        tokio::fs::write(path, &self.stream).await?;
         Ok(())
     }
 }
+
+pub fn execute_with_result<F, T>(func: F, tx: Sender<anyhow::Result<T>>) -> impl FnOnce()
+where
+    F: FnOnce() -> anyhow::Result<T> + Send + 'static,
+    T: Send + 'static,
+{
+    move || {
+        let result = func();
+        // Ignore the error if the receiver has been dropped
+        let _ = tx.send(result);
+    }
+}

src/encoder/mp3.rs

@@ -4,48 +4,69 @@ use mp3lame_encoder::Builder;
 use mp3lame_encoder::FlushNoGap;
 use mp3lame_encoder::InterleavedPcm;
 
-use super::Samples;
-use super::Encoder;
+use super::execute_with_result;
 use super::EncodedStream;
+use super::Encoder;
+use super::Samples;
 
 pub struct Mp3Encoder;
 
 impl Mp3Encoder {
-    fn build_encoder(&self, sample_rate: u32, channels: u32) -> anyhow::Result<mp3lame_encoder::Encoder> {
-        let mut builder = Builder::new().
-            ok_or(anyhow::anyhow!("Failed to create mp3 encoder"))?;
+    fn build_encoder(
+        &self,
+        sample_rate: u32,
+        channels: u32,
+    ) -> anyhow::Result<mp3lame_encoder::Encoder> {
+        let mut builder = Builder::new().ok_or(anyhow::anyhow!("Failed to create mp3 encoder"))?;
 
-        builder.set_sample_rate(sample_rate)
+        builder
+            .set_sample_rate(sample_rate)
             .map_err(|e| anyhow::anyhow!("Failed to set sample rate for mp3 encoder: {}", e))?;
-        builder.set_num_channels(channels as u8)
-            .map_err(|e| anyhow::anyhow!("Failed to set number of channels for mp3 encoder: {}", e))?;
-        builder.set_brate(mp3lame_encoder::Birtate::Kbps160)
+        builder.set_num_channels(channels as u8).map_err(|e| {
+            anyhow::anyhow!("Failed to set number of channels for mp3 encoder: {}", e)
+        })?;
+        builder
+            .set_brate(mp3lame_encoder::Birtate::Kbps160)
             .map_err(|e| anyhow::anyhow!("Failed to set bitrate for mp3 encoder: {}", e))?;
 
-        builder.build()
+        builder
+            .build()
             .map_err(|e| anyhow::anyhow!("Failed to build mp3 encoder: {}", e))
     }
 }
 
+#[async_trait::async_trait]
 impl Encoder for Mp3Encoder {
-    fn encode(&self, samples: Samples) -> anyhow::Result<EncodedStream> {
+    async fn encode(&self, samples: Samples) -> anyhow::Result<EncodedStream> {
         let mut mp3_encoder = self.build_encoder(samples.sample_rate, samples.channels)?;
 
+        let (tx, rx) = tokio::sync::oneshot::channel();
+
+        rayon::spawn(execute_with_result(
+            move || {
                 let samples: Vec<i16> = samples.samples.iter().map(|&x| x as i16).collect();
                 let input = InterleavedPcm(samples.as_slice());
                 let mut mp3_out_buffer = Vec::new();
                 mp3_out_buffer.reserve(mp3lame_encoder::max_required_buffer_size(samples.len()));
-        let encoded_size = mp3_encoder.encode(input, mp3_out_buffer.spare_capacity_mut())
+                let encoded_size = mp3_encoder
+                    .encode(input, mp3_out_buffer.spare_capacity_mut())
                     .map_err(|e| anyhow!("Failed to encode mp3: {}", e))?;
                 unsafe {
                     mp3_out_buffer.set_len(mp3_out_buffer.len().wrapping_add(encoded_size));
                 }
 
-        let encoded_size = mp3_encoder.flush::<FlushNoGap>(mp3_out_buffer.spare_capacity_mut())
+                let encoded_size = mp3_encoder
+                    .flush::<FlushNoGap>(mp3_out_buffer.spare_capacity_mut())
                     .map_err(|e| anyhow!("Failed to flush mp3 encoder: {}", e))?;
                 unsafe {
                     mp3_out_buffer.set_len(mp3_out_buffer.len().wrapping_add(encoded_size));
                 }
+                Ok(mp3_out_buffer)
+            },
+            tx,
+        ));
+
+        let mp3_out_buffer = rx.await??;
 
         Ok(EncodedStream::new(mp3_out_buffer))
     }

src/lib.rs

@@ -1,5 +1,5 @@
 pub mod download;
-pub mod file_sink;
+// pub mod file_sink;
 pub mod channel_sink;
 pub mod session;
 pub mod track;