Lib/idlelib/loader.py

   1 # Everything is done inside the loader function so that no other names
   2 # are placed in the global namespace.  Before user code is executed,
   3 # even this name is unbound.
   4 def loader():
   5     import sys, os, protocol, threading, time
   6     import Remote
   7
   8 ##  Use to debug the loading process itself:
   9 ##    sys.stdout = open('c:\\windows\\desktop\\stdout.txt','a')
  10 ##    sys.stderr = open('c:\\windows\\desktop\\stderr.txt','a')
  11
  12     # Ensure that there is absolutely no pollution of the global
  13     # namespace by deleting the global name of this function.
  14     global loader
  15     del loader
  16
  17     # Connect to IDLE
  18     try:
  19         client = protocol.Client()
  20     except protocol.connectionLost, cL:
  21         print 'loader: Unable to connect to IDLE', cL
  22         return
  23
  24     # Connect to an ExecBinding object that needs our help.  If
  25     # the user is starting multiple programs right now, we might get a
  26     # different one than the one that started us.  Proving that's okay is
  27     # left as an exercise to the reader.  (HINT:  Twelve, by the pigeonhole
  28     # principle)
  29     ExecBinding = client.getobject('ExecBinding')
  30     if not ExecBinding:
  31         print "loader: IDLE does not need me."
  32         return
  33
  34     # All of our input and output goes through ExecBinding.
  35     sys.stdin  = Remote.pseudoIn( ExecBinding.readline )
  36     sys.stdout = Remote.pseudoOut( ExecBinding.write.void, tag="stdout" )
  37     sys.stderr = Remote.pseudoOut( ExecBinding.write.void, tag="stderr" )
  38
  39     # Create a Remote object and start it running.
  40     remote = Remote.Remote(globals(), ExecBinding)
  41     rthread = threading.Thread(target=remote.mainloop)
  42     rthread.setDaemon(1)
  43     rthread.start()
  44
  45     # Block until either the client or the user program stops
  46     user = rthread.isAlive
  47     while user and client.isAlive():
  48         time.sleep(0.025)
  49
  50         if not user():
  51           user = hasattr(sys, "ready_to_exit") and sys.ready_to_exit
  52           for t in threading.enumerate():
  53             if not t.isDaemon() and t.isAlive() and t!=threading.currentThread():
  54               user = t.isAlive
  55               break
  56
  57     # We need to make sure we actually exit, so that the user doesn't get
  58     #   stuck with an invisible process.  We want to finalize C modules, so
  59     #   we don't use os._exit(), but we don't call sys.exitfunc, which might
  60     #   block forever.
  61     del sys.exitfunc
  62     sys.exit()
  63
  64 loader()