# # # 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))