Handle pre-epoch file timestamps consistently and record Rust audit

apps/desktop/src-tauri/src/media_preview.rs

@@ -13,7 +13,6 @@ use std::{
         atomic::{AtomicUsize, Ordering},
         Arc, Mutex,
     },
-    time::UNIX_EPOCH,
 };
 use tauri::http::{header, Method, Request, Response, StatusCode};
 
@@ -38,8 +37,7 @@ impl Identity {
         let modified_ns = metadata
             .modified()
             .ok()
-            .and_then(|value| value.duration_since(UNIX_EPOCH).ok())
-            .and_then(|value| i64::try_from(value.as_nanos()).ok())
+            .and_then(|value| searchi_media::unix_time_ns(value).ok())
             .ok_or("Preview source timestamp is unavailable.")?;
         Ok(Self {
             len: metadata.len(),
@@ -503,6 +501,35 @@ mod tests {
         }
     }
 
+    #[test]
+    fn pre_epoch_media_is_indexed_and_previewed_with_current_identity() {
+        let mut fixture = Fixture::new(64);
+        File::options()
+            .write(true)
+            .open(&fixture.path)
+            .unwrap()
+            .set_times(
+                std::fs::FileTimes::new()
+                    .set_modified(std::time::UNIX_EPOCH - std::time::Duration::from_secs(1)),
+            )
+            .unwrap();
+        assert_eq!(
+            fixture.request(Method::GET, None).status(),
+            StatusCode::GONE
+        );
+        SearchIndex::open(&fixture.database)
+            .unwrap()
+            .index_folder(fixture.path.parent().unwrap())
+            .unwrap();
+        fixture.token = fixture
+            .registry
+            .grant(fixture.database.clone(), fixture.path.clone(), "audio")
+            .unwrap();
+        let response = fixture.request(Method::GET, None);
+        assert_eq!(response.status(), StatusCode::OK);
+        assert_eq!(response.body().len(), 64);
+    }
+
     #[test]
     fn large_media_never_allocates_the_full_file_and_head_is_metadata_only() {
         let fixture = Fixture::new(8 * MAX_CHUNK);