Python File Type Support.md

Python File Type Support

• Python File Type Support
  • Python os.stat() file types
  • Python os.path file types
  • Python pathlib file types
  • Python file type detection

Python os.stat() file types

https://docs.python.org/3/library/stat.html

Python stat module supported "file" types

• "file" is the UNIX sense that everything is a file

Function	Type
stat.S_ISDIR(mode)	directory
stat.S_ISCHR(mode)	character special device file
stat.S_ISBLK(mode)	block special device file
stat.S_ISREG(mode)	regular file
stat.S_ISFIFO(mode)	FIFO (named pipe)
stat.S_ISLNK(mode)	symbolic link
stat.S_ISSOCK(mode)	socket
stat.S_ISDOOR(mode)	door (new Python 3.4)
stat.S_ISPORT(mode)	event port (new Python 3.4)
stat.S_ISWHT(mode)	whiteout (new Python 3.4)

What is a door anyway?

• https://en.wikipedia.org/wiki/Doors_(computing)
• Door is a particular kind of file structure that is used as a "remote procedure call" for a "server", "threads" model. Really ever implemented on Solaris

What is an event port anyway?

• https://docs.oracle.com/cd/E19253-01/817-0547/whatsnew-196/index.html
• I think this is a file type that only Solaris really supports that is used for sending events between processes.
• I've been unable to find very good documentation on this one.

What is a whiteout anyway?

• https://lwn.net/Articles/265240/
• https://lwn.net/Articles/325369/
• Summarize:
  • A whiteout is a thing that exists on some "overlay" filesystem.
  • It represents "there is no file here", when there maybe a file existing at a lower level of the overlay.
  • There is question of how good of an idea they are, and support is limited.
  • Base linux does not support it, but BSD does.

Python os.path file types

https://docs.python.org/3/library/os.path.html

Function	Type
os.path.isfile(path)	regular file
os.path.isdir(path)	directory
os.path.isjunction(path)	junction (New in version 3.12)
os.path.islink(path)	symbolic link
os.path.ismount(path)	mount point
os.path.isdevdrive(path)	Windows Dev Drive (New in version 3.12)

What is a junction?

• https://www.computerhope.com/jargon/j/junction.htm
• I think this is like a symlink, but it only works for pointing to directories that are on the same logical volume

What is a Windows Dev Drive?

• https://docs.python.org/3/library/os.path.html#module-os.path
• A Dev Drive is optimized for developer scenarios, and offers faster performance for reading and writing files.
• It is recommended for use for source code, temporary build directories, package caches, and other IO-intensive operations.
• Very strange.

Python pathlib file types

Function	Type
Path.is_dir()	directory
Path.is_file()	regular file
Path.is_junction()	junction (New in version 3.12)
Path.is_mount()	mount point (New in version 3.7; 3.12: Windows support was added)
Path.is_symlink()	symbolic link
Path.is_socket()	Unix socket
Path.is_fifo()	FIFO
Path.is_block_device()	block device
Path.is_char_device()	character device

Python file type detection

File Type	os.stat()	os.path	pathlib
regular file	✅	✅	✅
directory	✅	✅	✅
symbolic link	✅	✅	✅
mount point	❌	✅	✅
socket	✅	❌	✅
FIFO	✅	❌	✅
block device	✅	❌	✅
character device	✅	❌	✅
junction	❌	✅	✅
door	✅	❌	❌
event port	✅	❌	❌
whiteout	✅	❌	❌
Windows Dev Drive	❌	✅	❌