dev: Everything is Assets

app/storage/hashing.py

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+import asyncio
+import os
+from typing import IO, Union
+
+from blake3 import blake3
+
+DEFAULT_CHUNK = 8 * 1024 * 1024  # 8 MiB
+
+
+def _hash_file_obj_sync(file_obj: IO[bytes], chunk_size: int) -> str:
+    """Hash an already-open binary file object by streaming in chunks.
+    - Seeks to the beginning before reading (if supported).
+    - Restores the original position afterward (if tell/seek are supported).
+    """
+    if chunk_size <= 0:
+        chunk_size = DEFAULT_CHUNK
+
+    orig_pos = None
+    if hasattr(file_obj, "tell"):
+        orig_pos = file_obj.tell()
+
+    try:
+        if hasattr(file_obj, "seek"):
+            file_obj.seek(0)
+
+        h = blake3()
+        while True:
+            chunk = file_obj.read(chunk_size)
+            if not chunk:
+                break
+            h.update(chunk)
+        return h.hexdigest()
+    finally:
+        if hasattr(file_obj, "seek") and orig_pos is not None:
+            file_obj.seek(orig_pos)
+
+
+def blake3_hash_sync(
+    fp: Union[str, bytes, os.PathLike[str], os.PathLike[bytes], IO[bytes]],
+    chunk_size: int = DEFAULT_CHUNK,
+) -> str:
+    """Returns a BLAKE3 hex digest for ``fp``, which may be:
+      - a filename (str/bytes) or PathLike
+      - an open binary file object
+
+    If ``fp`` is a file object, it must be opened in **binary** mode and support
+    ``read``, ``seek``, and ``tell``. The function will seek to the start before
+    reading and will attempt to restore the original position afterward.
+    """
+    if hasattr(fp, "read"):
+        return _hash_file_obj_sync(fp, chunk_size)
+
+    with open(os.fspath(fp), "rb") as f:
+        return _hash_file_obj_sync(f, chunk_size)
+
+
+async def blake3_hash(
+    fp: Union[str, bytes, os.PathLike[str], os.PathLike[bytes], IO[bytes]],
+    chunk_size: int = DEFAULT_CHUNK,
+) -> str:
+    """Async wrapper for ``blake3_hash_sync``.
+    Uses a worker thread so the event loop remains responsive.
+    """
+    # If it is a path, open inside the worker thread to keep I/O off the loop.
+    if hasattr(fp, "read"):
+        return await asyncio.to_thread(blake3_hash_sync, fp, chunk_size)
+
+    def _worker() -> str:
+        with open(os.fspath(fp), "rb") as f:
+            return _hash_file_obj_sync(f, chunk_size)
+
+    return await asyncio.to_thread(_worker)