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Mini Shell
Mini Shell
#
#
#
import select
import fcntl
import os
class NonBlockingFile:
def __init__(self, fd):
# Keep a copy of the file descriptor
self.fd = fd
fcntl.fcntl(self.fd.fileno(), fcntl.F_SETFL, os.O_NDELAY)
# Set the callback-related stuff
self.read_fd_set = []
self.write_fd_set = []
self.exc_fd_set = []
self.user_data = None
self.callback = None
def set_callback(self, read_fd_set, write_fd_set, exc_fd_set,
user_data, callback):
self.read_fd_set = read_fd_set
# Make the objects non-blocking
for f in self.read_fd_set:
fcntl.fcntl(f.fileno(), fcntl.F_SETFL, os.O_NDELAY)
self.write_fd_set = write_fd_set
self.exc_fd_set = exc_fd_set
self.user_data = user_data
self.callback = callback
def read(self, amt=0):
while 1:
status_changed = 0
readfds = self.read_fd_set + [self.fd]
writefds = self.write_fd_set
excfds = self.exc_fd_set
print("Calling select", readfds)
readfds, writefds, excfds = select.select(readfds, writefds, excfds)
print("Select returned", readfds, writefds, excfds)
if self.fd in readfds:
# Our own file descriptor has changed status
# Mark this, but also try to call the callback with the rest
# of the file descriptors that changed status
status_changed = 1
readfds.remove(self.fd)
if self.callback and (readfds or writefds or excfds):
self.callback(readfds, writefds, excfds, self.user_data)
if status_changed:
break
print("Returning")
return self.fd.read(amt)
def write(self, data):
return self.fd.write(data)
def __getattr__(self, name):
return getattr(self.fd, name)
def callback(r, w, e, user_data):
print("Callback called", r, w, e)
print(r[0].read())
if __name__ == '__main__':
import socket
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect(("localhost", 5555))
f = s.makefile()
ss = NonBlockingFile(f)
s2 = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s2.connect(("localhost", 5556))
f = s2.makefile()
ss.set_callback([f], [], [], None, callback)
xx = ss.read()
print(len(xx))
Zerion Mini Shell 1.0