refactor(assets): modular architecture + async two-phase scanner & background seeder (#12621)

app/assets/services/file_utils.py

@@ -0,0 +1,70 @@
+import os
+
+
+def get_mtime_ns(stat_result: os.stat_result) -> int:
+    """Extract mtime in nanoseconds from a stat result."""
+    return getattr(
+        stat_result, "st_mtime_ns", int(stat_result.st_mtime * 1_000_000_000)
+    )
+
+
+def get_size_and_mtime_ns(path: str, follow_symlinks: bool = True) -> tuple[int, int]:
+    """Get file size in bytes and mtime in nanoseconds."""
+    st = os.stat(path, follow_symlinks=follow_symlinks)
+    return st.st_size, get_mtime_ns(st)
+
+
+def verify_file_unchanged(
+    mtime_db: int | None,
+    size_db: int | None,
+    stat_result: os.stat_result,
+) -> bool:
+    """Check if a file is unchanged based on mtime and size.
+
+    Returns True if the file's mtime and size match the database values.
+    Returns False if mtime_db is None or values don't match.
+
+    size_db=None means don't check size; 0 is a valid recorded size.
+    """
+    if mtime_db is None:
+        return False
+    actual_mtime_ns = get_mtime_ns(stat_result)
+    if int(mtime_db) != int(actual_mtime_ns):
+        return False
+    if size_db is not None:
+        return int(stat_result.st_size) == int(size_db)
+    return True
+
+
+def is_visible(name: str) -> bool:
+    """Return True if a file or directory name is visible (not hidden)."""
+    return not name.startswith(".")
+
+
+def list_files_recursively(base_dir: str) -> list[str]:
+    """Recursively list all files in a directory, following symlinks."""
+    out: list[str] = []
+    base_abs = os.path.abspath(base_dir)
+    if not os.path.isdir(base_abs):
+        return out
+    # Track seen real directory identities to prevent circular symlink loops
+    seen_dirs: set[tuple[int, int]] = set()
+    for dirpath, subdirs, filenames in os.walk(
+        base_abs, topdown=True, followlinks=True
+    ):
+        try:
+            st = os.stat(dirpath)
+            dir_id = (st.st_dev, st.st_ino)
+        except OSError:
+            subdirs.clear()
+            continue
+        if dir_id in seen_dirs:
+            subdirs.clear()
+            continue
+        seen_dirs.add(dir_id)
+        subdirs[:] = [d for d in subdirs if is_visible(d)]
+        for name in filenames:
+            if not is_visible(name):
+                continue
+            out.append(os.path.abspath(os.path.join(dirpath, name)))
+    return out