DOC: Clarify method in docstring

IPython/terminal/pt_inputhooks/wx.py

@@ -1,217 +1,219 b''
 """Enable wxPython to be used interactively in prompt_toolkit
 """
 
 import sys
 import signal
 import time
 from timeit import default_timer as clock
 import wx
 
 
 def ignore_keyboardinterrupts(func):
     """Decorator which causes KeyboardInterrupt exceptions to be ignored during
     execution of the decorated function.
 
     This is used by the inputhook functions to handle the event where the user
     presses CTRL+C while IPython is idle, and the inputhook loop is running. In
     this case, we want to ignore interrupts.
     """
     def wrapper(*args, **kwargs):
         try:
             func(*args, **kwargs)
         except KeyboardInterrupt:
             pass
     return wrapper
 
 
 @ignore_keyboardinterrupts
 def inputhook_wx1(context):
     """Run the wx event loop by processing pending events only.
 
     This approach seems to work, but its performance is not great as it
     relies on having PyOS_InputHook called regularly.
     """
     app = wx.GetApp()
     if app is not None:
         assert wx.Thread_IsMain()
 
         # Make a temporary event loop and process system events until
         # there are no more waiting, then allow idle events (which
         # will also deal with pending or posted wx events.)
         evtloop = wx.EventLoop()
         ea = wx.EventLoopActivator(evtloop)
         while evtloop.Pending():
             evtloop.Dispatch()
         app.ProcessIdle()
         del ea
     return 0
 
 
 class EventLoopTimer(wx.Timer):
 
     def __init__(self, func):
         self.func = func
         wx.Timer.__init__(self)
 
     def Notify(self):
         self.func()
 
 
 class EventLoopRunner(object):
 
     def Run(self, time, input_is_ready):
         self.input_is_ready = input_is_ready
         self.evtloop = wx.EventLoop()
         self.timer = EventLoopTimer(self.check_stdin)
         self.timer.Start(time)
         self.evtloop.Run()
 
     def check_stdin(self):
         if self.input_is_ready():
             self.timer.Stop()
             self.evtloop.Exit()
 
 
 @ignore_keyboardinterrupts
 def inputhook_wx2(context):
     """Run the wx event loop, polling for stdin.
 
     This version runs the wx eventloop for an undetermined amount of time,
     during which it periodically checks to see if anything is ready on
     stdin.  If anything is ready on stdin, the event loop exits.
 
     The argument to elr.Run controls how often the event loop looks at stdin.
     This determines the responsiveness at the keyboard.  A setting of 1000
     enables a user to type at most 1 char per second.  I have found that a
     setting of 10 gives good keyboard response.  We can shorten it further,
     but eventually performance would suffer from calling select/kbhit too
     often.
     """
     app = wx.GetApp()
     if app is not None:
         assert wx.Thread_IsMain()
         elr = EventLoopRunner()
         # As this time is made shorter, keyboard response improves, but idle
         # CPU load goes up.  10 ms seems like a good compromise.
         elr.Run(time=10,  # CHANGE time here to control polling interval
                 input_is_ready=context.input_is_ready)
     return 0
 
 
 @ignore_keyboardinterrupts
 def inputhook_wx3(context):
     """Run the wx event loop by processing pending events only.
 
     This is like inputhook_wx1, but it keeps processing pending events
     until stdin is ready.  After processing all pending events, a call to
     time.sleep is inserted.  This is needed, otherwise, CPU usage is at 100%.
     This sleep time should be tuned though for best performance.
     """
     app = wx.GetApp()
     if app is not None:
         assert wx.Thread_IsMain()
 
         # The import of wx on Linux sets the handler for signal.SIGINT
         # to 0.  This is a bug in wx or gtk.  We fix by just setting it
         # back to the Python default.
         if not callable(signal.getsignal(signal.SIGINT)):
             signal.signal(signal.SIGINT, signal.default_int_handler)
 
         evtloop = wx.EventLoop()
         ea = wx.EventLoopActivator(evtloop)
         t = clock()
         while not context.input_is_ready():
             while evtloop.Pending():
                 t = clock()
                 evtloop.Dispatch()
             app.ProcessIdle()
             # We need to sleep at this point to keep the idle CPU load
             # low.  However, if sleep to long, GUI response is poor.  As
             # a compromise, we watch how often GUI events are being processed
             # and switch between a short and long sleep time.  Here are some
             # stats useful in helping to tune this.
             # time    CPU load
             # 0.001   13%
             # 0.005   3%
             # 0.01    1.5%
             # 0.05    0.5%
             used_time = clock() - t
             if used_time > 10.0:
                 # print 'Sleep for 1 s'  # dbg
                 time.sleep(1.0)
             elif used_time > 0.1:
                 # Few GUI events coming in, so we can sleep longer
                 # print 'Sleep for 0.05 s'  # dbg
                 time.sleep(0.05)
             else:
                 # Many GUI events coming in, so sleep only very little
                 time.sleep(0.001)
         del ea
     return 0
 
 
 @ignore_keyboardinterrupts
 def inputhook_wxphoenix(context):
     """Run the wx event loop until the user provides more input.
 
     This function uses the same approach to that used in
-    ipykernel.eventloops.loop_wx.
+    ipykernel.eventloops.loop_wx. The wx.MainLoop is executed, and a wx.Timer
+    is used to periodically poll the context for input. As soon as input is
+    ready, the wx.MainLoop is stopped.
     """
 
     app = wx.GetApp()
 
     if app is None:
         return
 
     if context.input_is_ready():
         return
 
     assert wx.IsMainThread()
 
     # Wx uses milliseconds
     poll_interval = 100
 
     # We have to create a dummy wx.Frame, otherwise wx.App.MainLoop will know
     # that it has nothing to do, and will return immediately.
     frame = getattr(inputhook_wxphoenix, '_frame', None)
     if frame is None:
         inputhook_wxphoenix._frame = frame = wx.Frame(None)
         frame.Show(False)
 
     # Use a wx.Timer to periodically check whether input is ready - as soon as
     # it is, we exit the main loop
     def poll(ev):
         if context.input_is_ready():
             app.ExitMainLoop()
 
     timer = wx.Timer()
     timer.Start(poll_interval)
     timer.Bind(wx.EVT_TIMER, poll)
 
     # The import of wx on Linux sets the handler for signal.SIGINT to 0.  This
     # is a bug in wx or gtk.  We fix by just setting it back to the Python
     # default.
     if not callable(signal.getsignal(signal.SIGINT)):
         signal.signal(signal.SIGINT, signal.default_int_handler)
 
     app.MainLoop()
 
 
 # Get the major wx version number to figure out what input hook we should use.
 major_version = 3
 
 try:
     major_version = int(wx.__version__[0])
 except Exception:
     pass
 
 # Use the phoenix hook on all platforms for wxpython >= 4
 if major_version >= 4:
     inputhook = inputhook_wxphoenix
 # On OSX, evtloop.Pending() always returns True, regardless of there being
 # any events pending. As such we can't use implementations 1 or 3 of the
 # inputhook as those depend on a pending/dispatch loop.
 elif sys.platform == 'darwin':
     inputhook = inputhook_wx2
 else:
     inputhook = inputhook_wx3