Function inputhook

IPython/terminal/pt_inputhooks/tk.py:46–90

Inputhook for Tk. Run the Tk eventloop until prompt-toolkit needs to process the next input.

(inputhook_context)

import tkinter

def inputhook(inputhook_context):
    """
    Inputhook for Tk.
    Run the Tk eventloop until prompt-toolkit needs to process the next input.
    """
    # Get the current TK application.
    root = tkinter._default_root

    def wait_using_filehandler():
        """
        Run the TK eventloop until the file handler that we got from the
        inputhook becomes readable.
        """
        # Add a handler that sets the stop flag when `prompt-toolkit` has input
        # to process.
        stop = [False]
        def done(*a):
            stop[0] = True

        root.createfilehandler(inputhook_context.fileno(), _tkinter.READABLE, done)

        # Run the TK event loop as long as we don't receive input.
        while root.dooneevent(_tkinter.ALL_EVENTS):
            if stop[0]:
                break

        root.deletefilehandler(inputhook_context.fileno())

    def wait_using_polling():
        """
        Windows TK doesn't support 'createfilehandler'.
        So, run the TK eventloop and poll until input is ready.
        """
        while not inputhook_context.input_is_ready():
            while root.dooneevent(_tkinter.ALL_EVENTS | _tkinter.DONT_WAIT):
                 pass
            # Sleep to make the CPU idle, but not too long, so that the UI
            # stays responsive.
            time.sleep(.01)

    if root is not None:
        if hasattr(root, 'createfilehandler'):
            wait_using_filehandler()
        else:
            wait_using_polling()