From 9b3f4a5fe620a3c4dca20b20930dbd0b3fe722b3 Mon Sep 17 00:00:00 2001
From: 409 <409dev@protonmail.com>
Date: Fri, 29 Aug 2025 23:34:21 +0200
Subject: [PATCH] stream zip archive creation

---
 backend/Cargo.lock                      |   1 +
 backend/Cargo.toml                      |   3 +-
 backend/src/bin/backend/main.rs         |   2 +-
 backend/src/lib/outbound/file_system.rs | 105 ++++++++++++++++--------
 4 files changed, 75 insertions(+), 36 deletions(-)

diff --git a/backend/Cargo.lock b/backend/Cargo.lock
index 0975a34..b68560b 100644
--- a/backend/Cargo.lock
+++ b/backend/Cargo.lock
@@ -2806,6 +2806,7 @@ dependencies = [
  "sqlx",
  "thiserror 2.0.12",
  "tokio",
+ "tokio-stream",
  "tokio-util",
  "tower",
  "tower-http",
diff --git a/backend/Cargo.toml b/backend/Cargo.toml
index a0399f6..d879ade 100644
--- a/backend/Cargo.toml
+++ b/backend/Cargo.toml
@@ -38,7 +38,8 @@ sqlx = { version = "0.8.6", features = [
 ] }
 thiserror = "2.0.12"
 tokio = { version = "1.46.1", features = ["full"] }
-tokio-util = "0.7.15"
+tokio-stream = "0.1.17"
+tokio-util = { version = "0.7.15", features = ["io-util"] }
 tower = "0.5.2"
 tower-http = { version = "0.6.6", features = ["cors", "fs", "trace"] }
 tracing = "0.1.41"
diff --git a/backend/src/bin/backend/main.rs b/backend/src/bin/backend/main.rs
index 32c818c..d61bb6c 100644
--- a/backend/src/bin/backend/main.rs
+++ b/backend/src/bin/backend/main.rs
@@ -11,7 +11,7 @@ use warren::{
     },
 };
 
-#[tokio::main]
+#[tokio::main(flavor = "multi_thread")]
 async fn main() -> anyhow::Result<()> {
     dotenv::dotenv().ok();
 
diff --git a/backend/src/lib/outbound/file_system.rs b/backend/src/lib/outbound/file_system.rs
index c8fdc08..29d69ce 100644
--- a/backend/src/lib/outbound/file_system.rs
+++ b/backend/src/lib/outbound/file_system.rs
@@ -1,16 +1,16 @@
+use anyhow::{Context as _, anyhow, bail};
+use futures_util::TryStreamExt;
+use rustix::fs::{Statx, statx};
 use std::{
-    io::{Cursor, Write},
+    io::Write,
     os::unix::fs::MetadataExt,
     path::{Path, PathBuf},
 };
-
-use anyhow::{Context, anyhow, bail};
-use futures_util::TryStreamExt;
-use rustix::fs::{Statx, statx};
 use tokio::{
     fs::{self},
     io::{self, AsyncReadExt as _, AsyncWriteExt as _},
 };
+use tokio_stream::wrappers::ReceiverStream;
 use tokio_util::io::ReaderStream;
 
 use crate::{
@@ -223,38 +223,19 @@ impl FileSystem {
         if metadata.is_dir() {
             drop(file);
 
-            let options = zip::write::SimpleFileOptions::default()
-                .compression_method(zip::CompressionMethod::Zstd)
-                .unix_permissions(0o755);
+            let (sync_tx, sync_rx) =
+                std::sync::mpsc::channel::<Result<bytes::Bytes, std::io::Error>>();
+            let (tx, rx) =
+                tokio::sync::mpsc::channel::<Result<bytes::Bytes, std::io::Error>>(65536);
 
-            let mut file_buf = Vec::new();
-            let zip_buf = Vec::new();
-            let cursor = Cursor::new(zip_buf);
-            let mut zip = zip::ZipWriter::new(cursor);
-
-            for entry_path_buf in walk_dir(&path).await? {
-                let entry_path = entry_path_buf.as_path();
-                let entry_str = entry_path
-                    .strip_prefix(&path)?
-                    .to_str()
-                    .context("Failed to get directory entry name")?;
-
-                if entry_path.is_dir() {
-                    zip.add_directory(entry_str, options)?;
-                    continue;
+            tokio::task::spawn(async move {
+                while let Ok(v) = sync_rx.recv() {
+                    let _ = tx.send(v).await;
                 }
+            });
+            tokio::task::spawn(create_zip(path, sync_tx));
 
-                zip.start_file(entry_str, options)?;
-                let mut entry_file = tokio::fs::File::open(entry_path).await?;
-                entry_file.read_to_end(&mut file_buf).await?;
-                zip.write_all(&file_buf)?;
-                file_buf.clear();
-            }
-
-            let mut cursor = zip.finish()?;
-
-            cursor.set_position(0);
-            let stream = FileStream::new(ReaderStream::new(cursor));
+            let stream = FileStream::new(ReceiverStream::new(rx));
 
             return Ok(stream);
         }
@@ -479,3 +460,59 @@ where
 
     Ok(files)
 }
+
+async fn create_zip<P>(
+    path: P,
+    tx: std::sync::mpsc::Sender<Result<bytes::Bytes, std::io::Error>>,
+) -> anyhow::Result<()>
+where
+    P: AsRef<Path>,
+{
+    let options = zip::write::SimpleFileOptions::default()
+        .compression_method(zip::CompressionMethod::Deflated)
+        .unix_permissions(0o644);
+
+    let mut file_buf = Vec::new();
+    let mut zip = zip::write::ZipWriter::new_stream(ChannelWriter(tx));
+
+    for entry_path_buf in walk_dir(&path).await? {
+        let entry_path = entry_path_buf.as_path();
+        let entry_str = entry_path
+            .strip_prefix(&path)?
+            .to_str()
+            .context("Failed to get directory entry name")?;
+
+        if entry_path.is_dir() {
+            zip.add_directory(entry_str, options)?;
+            continue;
+        }
+
+        zip.start_file(entry_str, options)?;
+        let mut entry_file = tokio::fs::File::open(entry_path).await?;
+        entry_file.read_to_end(&mut file_buf).await?;
+        zip.write_all(&file_buf)?;
+        file_buf.clear();
+    }
+
+    drop(zip.finish()?);
+
+    Ok(())
+}
+
+struct ChannelWriter(std::sync::mpsc::Sender<Result<bytes::Bytes, std::io::Error>>);
+
+impl Write for ChannelWriter {
+    fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
+        let len = buf.len();
+        let data = bytes::Bytes::copy_from_slice(&buf[..(len)]);
+
+        self.0
+            .send(Ok(data))
+            .map(|_| len)
+            .map_err(|_| std::io::ErrorKind::Other.into())
+    }
+
+    fn flush(&mut self) -> std::io::Result<()> {
+        Ok(())
+    }
+}