openpilot v0.9.6 release

date: 2024-01-12T10:13:37
master commit: ba792d576a49a0899b88a753fa1c52956bedf9e6

common/file_helpers.py

@@ -0,0 +1,38 @@
+import os
+import tempfile
+import contextlib
+from typing import Optional
+
+
+class CallbackReader:
+  """Wraps a file, but overrides the read method to also
+  call a callback function with the number of bytes read so far."""
+  def __init__(self, f, callback, *args):
+    self.f = f
+    self.callback = callback
+    self.cb_args = args
+    self.total_read = 0
+
+  def __getattr__(self, attr):
+    return getattr(self.f, attr)
+
+  def read(self, *args, **kwargs):
+    chunk = self.f.read(*args, **kwargs)
+    self.total_read += len(chunk)
+    self.callback(*self.cb_args, self.total_read)
+    return chunk
+
+
+@contextlib.contextmanager
+def atomic_write_in_dir(path: str, mode: str = 'w', buffering: int = -1, encoding: Optional[str] = None, newline: Optional[str] = None,
+                        overwrite: bool = False):
+  """Write to a file atomically using a temporary file in the same directory as the destination file."""
+  dir_name = os.path.dirname(path)
+
+  if not overwrite and os.path.exists(path):
+    raise FileExistsError(f"File '{path}' already exists. To overwrite it, set 'overwrite' to True.")
+
+  with tempfile.NamedTemporaryFile(mode=mode, buffering=buffering, encoding=encoding, newline=newline, dir=dir_name, delete=False) as tmp_file:
+    yield tmp_file
+    tmp_file_name = tmp_file.name
+  os.replace(tmp_file_name, path)