MappedFile#

class MappedFile(**kwargs)#

The MappedFile represents a file mapping created with new(). It has only private members and should not be accessed directly.

Constructors#

class MappedFile
classmethod new(filename: str, writable: bool) → MappedFile#

Maps a file into memory. On UNIX, this is using the mmap() function.

If writable is True, the mapped buffer may be modified, otherwise it is an error to modify the mapped buffer. Modifications to the buffer are not visible to other processes mapping the same file, and are not written back to the file.

Note that modifications of the underlying file might affect the contents of the MappedFile. Therefore, mapping should only be used if the file will not be modified, or if all modifications of the file are done atomically (e.g. using file_set_contents()).

If filename is the name of an empty, regular file, the function will successfully return an empty MappedFile. In other cases of size 0 (e.g. device files such as /dev/null), error will be set to the FileError value INVAL.

Added in version 2.8.

Parameters:

  • filename – The path of the file to load, in the GLib filename encoding

  • writable – whether the mapping should be writable

classmethod new_from_fd(fd: int, writable: bool) → MappedFile#

Maps a file into memory. On UNIX, this is using the mmap() function.

If writable is True, the mapped buffer may be modified, otherwise it is an error to modify the mapped buffer. Modifications to the buffer are not visible to other processes mapping the same file, and are not written back to the file.

Note that modifications of the underlying file might affect the contents of the MappedFile. Therefore, mapping should only be used if the file will not be modified, or if all modifications of the file are done atomically (e.g. using file_set_contents()).

Added in version 2.32.

Parameters:

  • fd – The file descriptor of the file to load

  • writable – whether the mapping should be writable

Methods#

class MappedFile
free() → None#

This call existed before MappedFile had refcounting and is currently exactly the same as unref().

Added in version 2.8.

Deprecated since version 2.22: Use unref() instead.

get_bytes() → Bytes#

Creates a new Bytes which references the data mapped from file. The mapped contents of the file must not be modified after creating this bytes object, because a Bytes should be immutable.

Added in version 2.34.

get_contents() → str | None#

Returns the contents of a MappedFile.

Note that the contents may not be zero-terminated, even if the MappedFile is backed by a text file.

If the file is empty then None is returned.

Added in version 2.8.

get_length() → int#

Returns the length of the contents of a MappedFile.

Added in version 2.8.