refactor patch management and add ownership safeguards

1 files changed, 36 insertions, 0 deletions

diff --git a/backend/files.py b/backend/files.py
new file mode 100644
index 0000000..c5ec839
--- /dev/null
+++ b/backend/files.py
@@ -0,0 +1,36 @@
+"""Small filesystem helpers shared by backend services."""
+
+import filecmp
+import hashlib
+import json
+from pathlib import Path
+
+
+def file_sha256(path: Path) -> str:
+    digest = hashlib.sha256()
+    with path.open("rb") as stream:
+        for chunk in iter(lambda: stream.read(1024 * 1024), b""):
+            digest.update(chunk)
+    return digest.hexdigest()
+
+
+def files_match(file_a: Path, file_b: Path) -> bool:
+    try:
+        return file_a.is_file() and file_b.is_file() and filecmp.cmp(file_a, file_b, shallow=False)
+    except OSError:
+        return False
+
+
+def read_json(path: Path) -> dict:
+    try:
+        with path.open("r", encoding="utf-8") as stream:
+            payload = json.load(stream)
+        return payload if isinstance(payload, dict) else {}
+    except (OSError, ValueError, TypeError):
+        return {}
+
+
+def write_json(path: Path, payload: dict) -> None:
+    path.parent.mkdir(parents=True, exist_ok=True)
+    with path.open("w", encoding="utf-8") as stream:
+        json.dump(payload, stream, indent=2)