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- import os
- import tempfile
- import contextlib
- 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: str = None, newline: 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)
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