on_truncate Event

Fires when the OS needs to truncate (set the size of) a file.

Syntax

class FUSETruncateEventParams(object):
  @property
  def path() -> str: ...
  @property
  def file_context() -> int: ...
  @property
  def size() -> int: ...
  @property
  def result() -> int: ...
  @result.setter
  def result(value) -> None: ...

# In class FUSE:
@property
def on_truncate() -> Callable[[FUSETruncateEventParams], None]: ...
@on_truncate.setter
def on_truncate(event_hook: Callable[[FUSETruncateEventParams], None]) -> None: ...

Remarks

This event fires when the OS wants to set the size of the file, identified by either Path or FileContext.

Note: on non-Windows systems, FileContext may be 0 even for a file that is opened at the moment when the event fires.

The Size parameter contains the new file size. If the new size is larger than the old size, the added space is expected to be filled with null bytes ('\0').

The ResultCode parameter will always be 0 when the event is fired. If the event cannot be handled in a "successful" manner for some reason (e.g., a resource isn't available, security checks failed, etc.), set it to a negative error code value (e.g. -ENOENT to indicate that the file does not exist) to report an appropriate error. Please refer to the Error Reporting and Handling topic for more information.