Harden worker IPC and recoverable runtime staging

crates/searchi-assets/src/lib.rs

@@ -94,6 +94,27 @@ pub fn default_model_directory() -> Result<PathBuf> {
         .join("embeddinggemma2"))
 }
 
+/// Cheap location selection for optional bundled assets. This checks regular
+/// files and expected lengths only; `verify_cached` still verifies SHA-256
+/// before setup considers the model usable. Partial bundles use managed cache.
+pub fn has_model_files(directory: &Path) -> Result<bool> {
+    model_files_present(directory, &manifest()?.files)
+}
+
+fn model_files_present(directory: &Path, artifacts: &[Artifact]) -> Result<bool> {
+    for artifact in artifacts {
+        let metadata = match fs::metadata(directory.join(&artifact.path)) {
+            Ok(metadata) => metadata,
+            Err(error) if error.kind() == std::io::ErrorKind::NotFound => return Ok(false),
+            Err(error) => return Err(error).context("inspect bundled model artifact"),
+        };
+        if !metadata.is_file() || metadata.len() != artifact.bytes {
+            return Ok(false);
+        }
+    }
+    Ok(true)
+}
+
 /// Offline validation includes file length and full SHA-256, not mere existence.
 pub fn verify_cached(directory: &Path) -> Result<bool> {
     for artifact in manifest()?.files {
@@ -383,6 +404,32 @@ mod tests {
         );
     }
 
+    #[test]
+    fn optional_bundle_requires_both_regular_files_at_expected_sizes() {
+        let directory = tempfile::tempdir().unwrap();
+        let artifacts = [artifact("one.gguf", b"abc"), artifact("two.gguf", b"xyz")];
+        assert!(!model_files_present(directory.path(), &artifacts).unwrap());
+        fs::write(directory.path().join("one.gguf"), b"abc").unwrap();
+        assert!(!model_files_present(directory.path(), &artifacts).unwrap());
+        fs::create_dir(directory.path().join("two.gguf")).unwrap();
+        assert!(!model_files_present(directory.path(), &artifacts).unwrap());
+        fs::remove_dir(directory.path().join("two.gguf")).unwrap();
+        fs::write(directory.path().join("two.gguf"), b"xyz").unwrap();
+        assert!(model_files_present(directory.path(), &artifacts).unwrap());
+        fs::write(directory.path().join("one.gguf"), b"ab").unwrap();
+        assert!(!model_files_present(directory.path(), &artifacts).unwrap());
+    }
+
+    #[test]
+    fn bundled_file_presence_never_substitutes_for_sha_verification() {
+        let directory = tempfile::tempdir().unwrap();
+        let artifact = artifact("one.gguf", b"abc");
+        let path = directory.path().join(&artifact.path);
+        fs::write(&path, b"xyz").unwrap();
+        assert!(model_files_present(directory.path(), std::slice::from_ref(&artifact)).unwrap());
+        assert!(!verified(&path, &artifact).unwrap());
+    }
+
     #[test]
     fn same_size_corruption_is_detected_and_missing_cache_is_offline() {
         let directory = tempfile::tempdir().unwrap();