SIGINT fixing for twshell

IPython/shellglobals.py

@@ -0,0 +1,82 b''
+from IPython.genutils import Term,warn,error,flag_calls, ask_yes_no
+
+import thread,inspect
+
+try:
+    import ctypes
+    HAS_CTYPES = True
+except ImportError:
+    HAS_CTYPES = False
+
+
+# Globals
+# global flag to pass around information about Ctrl-C without exceptions
+KBINT = False
+
+# global flag to turn on/off Tk support.
+USE_TK = False
+
+# ID for the main thread, used for cross-thread exceptions
+MAIN_THREAD_ID = thread.get_ident()
+
+# Tag when runcode() is active, for exception handling
+CODE_RUN = None
+
+
+#-----------------------------------------------------------------------------
+# This class is trivial now, but I want to have it in to publish a clean
+# interface. Later when the internals are reorganized, code that uses this
+# shouldn't have to change.
+
+
+if HAS_CTYPES:
+    #  Add async exception support.  Trick taken from:
+    # http://sebulba.wikispaces.com/recipe+thread2
+    def _async_raise(tid, exctype):
+        """raises the exception, performs cleanup if needed"""
+        if not inspect.isclass(exctype):
+            raise TypeError("Only types can be raised (not instances)")
+        res = ctypes.pythonapi.PyThreadState_SetAsyncExc(tid,
+                                                         ctypes.py_object(exctype))
+        if res == 0:
+            raise ValueError("invalid thread id")
+        elif res != 1:
+            # """if it returns a number greater than one, you're in trouble, 
+            # and you should call it again with exc=NULL to revert the effect"""
+            ctypes.pythonapi.PyThreadState_SetAsyncExc(tid, 0)
+            raise SystemError("PyThreadState_SetAsyncExc failed")
+
+    def sigint_handler (signum,stack_frame):
+        """Sigint handler for threaded apps.
+
+        This is a horrible hack to pass information about SIGINT _without_
+        using exceptions, since I haven't been able to properly manage
+        cross-thread exceptions in GTK/WX.  In fact, I don't think it can be
+        done (or at least that's my understanding from a c.l.py thread where
+        this was discussed)."""
+
+        global KBINT
+
+        if CODE_RUN:
+            _async_raise(MAIN_THREAD_ID,KeyboardInterrupt)
+        else:
+            KBINT = True
+            print '\nKeyboardInterrupt - Press <Enter> to continue.',
+            Term.cout.flush()
+
+else:
+    def sigint_handler (signum,stack_frame):
+        """Sigint handler for threaded apps.
+
+        This is a horrible hack to pass information about SIGINT _without_
+        using exceptions, since I haven't been able to properly manage
+        cross-thread exceptions in GTK/WX.  In fact, I don't think it can be
+        done (or at least that's my understanding from a c.l.py thread where
+        this was discussed)."""
+
+        global KBINT
+
+        print '\nKeyboardInterrupt - Press <Enter> to continue.',
+        Term.cout.flush()
+        # Set global flag so that runsource can know that Ctrl-C was hit
+        KBINT = True

IPython/twshell.py

@@ -1,283 +1,280 b''
 import sys
 
 from twisted.internet import gtk2reactor
 gtk2reactor.install()
 
 from twisted.internet import reactor, threads
 
 """ change here to choose the plot shell with the MT option
     which should cost extra """
 
 from IPython.ipmaker import make_IPython
 from IPython.iplib import InteractiveShell 
 from IPython.ipstruct import Struct
 import Queue,thread,threading,signal
-
-from IPython.Shell import *
-
 from signal import signal, SIGINT
+from IPython.genutils import Term,warn,error,flag_calls, ask_yes_no
+import shellglobals
+
 
 def hijack_reactor():
     """Modifies Twisted's reactor with a dummy so user code does
     not block IPython.  This function returns the original
     'twisted.internet.reactor' that has been hijacked.
 
     NOTE: Make sure you call this *AFTER* you've installed
     the reactor of your choice.
     """
     from twisted import internet
     orig_reactor = internet.reactor
 
     class DummyReactor(object):
         def run(self):
             pass
         def __getattr__(self, name):
             return getattr(orig_reactor, name)
         def __setattr__(self, name, value):
             return setattr(orig_reactor, name, value)
     
     internet.reactor = DummyReactor()
     return orig_reactor
 
 class TwistedInteractiveShell(InteractiveShell):
     """Simple multi-threaded shell."""
 
     # Threading strategy taken from:
     # http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/65109, by Brian
     # McErlean and John Finlay.  Modified with corrections by Antoon Pardon,
     # from the pygtk mailing list, to avoid lockups with system calls.
 
     # class attribute to indicate whether the class supports threads or not.
     # Subclasses with thread support should override this as needed.
     isthreaded = True
 
     def __init__(self,name,usage=None,rc=Struct(opts=None,args=None),
                  user_ns=None,user_global_ns=None,banner2='',**kw):
         """Similar to the normal InteractiveShell, but with threading control"""
         
         InteractiveShell.__init__(self,name,usage,rc,user_ns,
                                   user_global_ns,banner2)
 
 
         # A queue to hold the code to be executed. 
         self.code_queue = Queue.Queue()
 
         # Stuff to do at closing time
         self._kill = None
         on_kill = kw.get('on_kill', [])
         # Check that all things to kill are callable:
         for t in on_kill:
             if not callable(t):
                 raise TypeError,'on_kill must be a list of callables'
         self.on_kill = on_kill
         # thread identity of the "worker thread" (that may execute code directly)
         self.worker_ident = None
         self.reactor_started = False
         self.first_run = True
         
     def runsource(self, source, filename="<input>", symbol="single"):
         """Compile and run some source in the interpreter.
 
         Modified version of code.py's runsource(), to handle threading issues.
         See the original for full docstring details."""
         
-        print "rs"
-        global KBINT
-        
         # If Ctrl-C was typed, we reset the flag and return right away
-        if KBINT:
-            KBINT = False
+        if shellglobals.KBINT:
+            shellglobals.KBINT = False
             return False
 
         if self._kill:
             # can't queue new code if we are being killed
             return True
         
         try:
             code = self.compile(source, filename, symbol)
         except (OverflowError, SyntaxError, ValueError):
             # Case 1
             self.showsyntaxerror(filename)
             return False
 
         if code is None:
             # Case 2
             return True
 
         # shortcut - if we are in worker thread, or the worker thread is not running, 
         # execute directly (to allow recursion and prevent deadlock if code is run early 
         # in IPython construction)
         
         if (not self.reactor_started or (self.worker_ident is None and not self.first_run) 
             or self.worker_ident == thread.get_ident()):
             InteractiveShell.runcode(self,code)
             return
 
-        self.first_run = False
         # Case 3
         # Store code in queue, so the execution thread can handle it.
  
         self.first_run = False
         completed_ev, received_ev = threading.Event(), threading.Event() 
         
         self.code_queue.put((code,completed_ev, received_ev))
 
         reactor.callLater(0.0,self.runcode)
         received_ev.wait(5)
         if not received_ev.isSet():
             # the mainloop is dead, start executing code directly
             print "Warning: Timeout for mainloop thread exceeded"
             print "switching to nonthreaded mode (until mainloop wakes up again)"
             self.worker_ident = None
         else:
+            shellglobals.CURRENT_COMPLETE_EV = completed_ev
             completed_ev.wait()
         
         return False
 
     def runcode(self):
         """Execute a code object.
 
         Multithreaded wrapper around IPython's runcode()."""
         
-        global CODE_RUN
         
         # we are in worker thread, stash out the id for runsource() 
         self.worker_ident = thread.get_ident()
 
         if self._kill:
             print >>Term.cout, 'Closing threads...',
             Term.cout.flush()
             for tokill in self.on_kill:
                 tokill()
             print >>Term.cout, 'Done.'
             # allow kill() to return
             self._kill.set()
             return True
 
-        # Install sigint handler.  We do it every time to ensure that if user
+        # Install SIGINT handler.  We do it every time to ensure that if user
         # code modifies it, we restore our own handling.
         try:
-            signal(SIGINT,sigint_handler)
+            pass
+            signal(SIGINT,shellglobals.sigint_handler)
         except SystemError:
             # This happens under Windows, which seems to have all sorts
             # of problems with signal handling.  Oh well...
             pass
 
         # Flush queue of pending code by calling the run methood of the parent
         # class with all items which may be in the queue.
         code_to_run = None
         while 1:
             try:
                 code_to_run, completed_ev, received_ev = self.code_queue.get_nowait()                
             except Queue.Empty:
                 break
             received_ev.set()
 
             
             # Exceptions need to be raised differently depending on which
             # thread is active.  This convoluted try/except is only there to
-            # protect against asynchronous exceptions, to ensure that a KBINT
+            # protect against asynchronous exceptions, to ensure that a shellglobals.KBINT
             # at the wrong time doesn't deadlock everything.  The global
             # CODE_TO_RUN is set to true/false as close as possible to the
             # runcode() call, so that the KBINT handler is correctly informed.
             try:
                 try:
-                   CODE_RUN = True
+                   shellglobals.CODE_RUN = True
                    InteractiveShell.runcode(self,code_to_run)
                 except KeyboardInterrupt:
                    print "Keyboard interrupted in mainloop"
                    while not self.code_queue.empty():
                       code = self.code_queue.get_nowait()
                    break
             finally:
-                CODE_RUN = False
+                shellglobals.CODE_RUN = False
                 # allow runsource() return from wait
                 completed_ev.set()                
         
         # This MUST return true for gtk threading to work
         return True
 
     def kill(self):
         """Kill the thread, returning when it has been shut down."""
         self._kill = threading.Event()
         reactor.callLater(0.0,self.runcode)
         self._kill.wait()
 
 
 
 class IPShellTwisted():
     """Run a Twisted reactor while in an IPython session.
 
     Python commands can be passed to the thread where they will be
     executed.  This is implemented by periodically checking for
     passed code using a Twisted reactor callback.
     """
 
     TIMEOUT = 0.01 # Millisecond interval between reactor runs.
 
     def __init__(self, argv=None, user_ns=None, debug=1,
                  shell_class=TwistedInteractiveShell):
 
         from twisted.internet import reactor
         self.reactor = hijack_reactor()
 
         mainquit = self.reactor.stop
 
         # Make sure IPython keeps going after reactor stop.
         def reactorstop():
             pass
         self.reactor.stop = reactorstop
         reactorrun_orig = self.reactor.run
         self.quitting = False
         def reactorrun():
             while True and not self.quitting:
                 reactorrun_orig()
         self.reactor.run = reactorrun
         
         self.IP = make_IPython(argv, user_ns=user_ns, debug=debug,
                                shell_class=shell_class,
                                on_kill=[mainquit])
 
         # threading.Thread.__init__(self)
 
     def run(self):
         self.IP.mainloop()
         self.quitting = True
         self.IP.kill()
 
     def mainloop(self):
         def mainLoopThreadDeath(r):
             print "mainLoopThreadDeath: ", str(r)
         def spawnMainloopThread():
             d=threads.deferToThread(self.run)
             d.addBoth(mainLoopThreadDeath)
         reactor.callWhenRunning(spawnMainloopThread)
         self.IP.reactor_started = True
         self.reactor.run()
         print "mainloop ending...."   
         
 exists = True
 
 
 if __name__ == '__main__':
     # Sample usage.
 
     # Create the shell object. This steals twisted.internet.reactor
     # for its own purposes, to make sure you've already installed a
     # reactor of your choice.
     shell = IPShellTwisted(
         argv=[],
         user_ns={'__name__': '__example__',
                  'hello': 'world',
                  },
         )
 
     # Run the mainloop.  This runs the actual reactor.run() method.
     # The twisted.internet.reactor object at this point is a dummy
     # object that passes through to the actual reactor, but prevents
     # run() from being called on it again.
     shell.mainloop()
 
     # You must exit IPython to terminate your program.
     print 'Goodbye!'