make cache async and fix parallel write bug

3 files changed, 52 insertions, 42 deletions

diff --git a/transcoder/src/bin/reproduce_decode_error.rs b/transcoder/src/bin/reproduce_decode_error.rs
index 84fa6fd..3e0ca3a 100644
--- a/transcoder/src/bin/reproduce_decode_error.rs
+++ b/transcoder/src/bin/reproduce_decode_error.rs
@@ -1,11 +1,13 @@
 use jellytranscoder::image::transcode;
 
-fn main() {
+#[tokio::main]
+async fn main() {
     transcode(
         jellycommon::AssetLocation::Cache(std::env::args().nth(2).unwrap().into()),
         1.0,
         1,
         1,
     )
+    .await
     .unwrap();
 }
diff --git a/transcoder/src/image.rs b/transcoder/src/image.rs
index 6da1be7..3865348 100644
--- a/transcoder/src/image.rs
+++ b/transcoder/src/image.rs
@@ -1,53 +1,60 @@
 use anyhow::Context;
 use image::{imageops::FilterType, ImageFormat};
-use jellybase::{cache_file, AssetLocationExt};
+use jellybase::{async_cache_file, AssetLocationExt};
 use jellycommon::AssetLocation;
 use log::{debug, info};
 use rgb::FromSlice;
-use std::{
-    fs::File,
-    io::{BufReader, Write},
-    path::PathBuf,
-};
+use std::{fs::File, io::BufReader};
+use tokio::io::AsyncWriteExt;
 
-pub fn transcode(
+pub async fn transcode(
     asset: AssetLocation,
     quality: f32,
     speed: u8,
     width: usize,
-) -> anyhow::Result<PathBuf> {
+) -> anyhow::Result<AssetLocation> {
     let original_path = asset.path();
-    let path = cache_file(&[
-        original_path.as_os_str().to_str().unwrap(),
-        &format!("{width} {quality} {speed}"),
-    ])
-    .path();
-    if !path.exists() {
-        info!("encoding {path:?} (speed={speed}, quality={quality}, width={width})");
-        // TODO shouldn't be neccessary with guessed format.
-        let file = BufReader::new(File::open(&original_path).context("opening source")?);
-        let mut reader = image::io::Reader::new(file);
-        reader.set_format(ImageFormat::Avif);
-        let reader = reader.with_guessed_format().context("guessing format")?;
-        debug!("guessed format (or fallback): {:?}", reader.format());
-        let original = reader.decode().context("decoding image")?.to_rgba8();
-        let image = image::imageops::resize(
-            &original,
-            width as u32,
-            width as u32 * original.height() / original.width(),
-            FilterType::Lanczos3,
-        );
-        let pixels = image.to_vec();
-        let encoded = ravif::Encoder::new()
-            .with_speed(speed.clamp(1, 10))
-            .with_quality(quality.clamp(1., 100.))
-            .encode_rgba(imgref::Img::new(
-                pixels.as_rgba(),
-                image.width() as usize,
-                image.height() as usize,
-            ))?;
-        info!("transcode finished");
-        File::create(&path)?.write_all(&encoded.avif_file)?;
-    }
-    Ok(path)
+    let asset = asset.clone();
+    Ok(async_cache_file(
+        &[
+            original_path.as_os_str().to_str().unwrap(),
+            &format!("{width} {quality} {speed}"),
+        ],
+        move |mut output| async move {
+            let encoded = tokio::task::spawn_blocking(move || {
+                let original_path = asset.path();
+                info!(
+                    "encoding {original_path:?} (speed={speed}, quality={quality}, width={width})"
+                );
+                // TODO shouldn't be neccessary with guessed format.
+                let file = BufReader::new(File::open(&original_path).context("opening source")?);
+                let mut reader = image::io::Reader::new(file);
+                reader.set_format(ImageFormat::Avif);
+                let reader = reader.with_guessed_format().context("guessing format")?;
+                debug!("guessed format (or fallback): {:?}", reader.format());
+                let original = reader.decode().context("decoding image")?.to_rgba8();
+                let image = image::imageops::resize(
+                    &original,
+                    width as u32,
+                    width as u32 * original.height() / original.width(),
+                    FilterType::Lanczos3,
+                );
+                let pixels = image.to_vec();
+                let encoded = ravif::Encoder::new()
+                    .with_speed(speed.clamp(1, 10))
+                    .with_quality(quality.clamp(1., 100.))
+                    .encode_rgba(imgref::Img::new(
+                        pixels.as_rgba(),
+                        image.width() as usize,
+                        image.height() as usize,
+                    ))?;
+                info!("transcode finished");
+                Ok::<_, anyhow::Error>(encoded)
+            })
+            .await??;
+            output.write_all(&encoded.avif_file).await?;
+            Ok(())
+        },
+    )
+    .await?)
 }
diff --git a/transcoder/src/lib.rs b/transcoder/src/lib.rs
index e74a7f5..010a7dd 100644
--- a/transcoder/src/lib.rs
+++ b/transcoder/src/lib.rs
@@ -3,4 +3,5 @@
     which is licensed under the GNU Affero General Public License (version 3); see /COPYING.
     Copyright (C) 2023 metamuffin <metamuffin.org>
 */
+#![feature(async_closure)]
 pub mod image;