⚡ Avoid blocking I/O in async context for rd_poll signature

services/receiver/src/rd_poll.rs

@@ -35,11 +35,11 @@ pub enum PollOutcome {
 /// Compute the `(mtime, size)` signature of all active RD files in `dir`, or `None` if
 /// any file's metadata cannot be read (missing file, RD closed, share
 /// unmounted).
-fn signature(dir: &Path) -> Option<FileSignature> {
+async fn signature(dir: &Path) -> Option<FileSignature> {
     let files = rd_dbf::resolve_rd_files(dir).ok()?;
     let mut sig = Vec::with_capacity(files.len());
     for file in files {
-        let meta = std::fs::metadata(dir.join(file)).ok()?;
+        let meta = tokio::fs::metadata(dir.join(file)).await.ok()?;
         sig.push((meta.modified().ok()?, meta.len()));
     }
     Some(sig)
@@ -74,7 +74,7 @@ pub async fn poll_once(
     dir: &Path,
     last: &mut Option<FileSignature>,
 ) -> PollOutcome {
-    let sig = signature(dir);
+    let sig = signature(dir).await;
     if let (Some(new), Some(old)) = (sig.as_ref(), last.as_ref())
         && new == old
     {

services/receiver/tests/bench_rd_poll.rs

@@ -0,0 +1,49 @@
+use receiver::control_api::AppState;
+use receiver::db::Db;
+use receiver::rd_dbf::RD_FILES;
+use receiver::rd_poll::{PollOutcome, poll_once};
+use std::path::{Path, PathBuf};
+use std::time::Instant;
+
+fn fixtures_dir() -> PathBuf {
+    PathBuf::from(env!("CARGO_MANIFEST_DIR"))
+        .join("tests")
+        .join("fixtures")
+        .join("rd")
+}
+
+fn copy_fixtures_to(dir: &Path) {
+    for file in RD_FILES {
+        std::fs::copy(fixtures_dir().join(file), dir.join(file)).unwrap();
+    }
+}
+
+#[tokio::test]
+async fn bench_rd_poll_signature() {
+    let (state, _rx) = AppState::new(Db::open_in_memory().unwrap(), "recv".to_owned());
+    let tmp = tempfile::tempdir().unwrap();
+    copy_fixtures_to(tmp.path());
+
+    let mut last = None;
+
+    // Warm-up / initial import pass
+    let first = poll_once(&state, tmp.path(), &mut last).await;
+    assert!(matches!(first, PollOutcome::Imported(_)));
+
+    let iterations = 1000;
+    let start = Instant::now();
+
+    for _ in 0..iterations {
+        let outcome = poll_once(&state, tmp.path(), &mut last).await;
+        assert!(matches!(outcome, PollOutcome::Skipped));
+    }
+
+    let elapsed = start.elapsed();
+    let avg = elapsed / iterations;
+
+    println!("\n==================================================");
+    println!("BENCHMARK: rd_poll change detection (signature check):");
+    println!("Total time for {iterations} iterations: {:?}", elapsed);
+    println!("Average time per poll pass: {:?}", avg);
+    println!("==================================================\n");
+}