Python code coverage for Lib/idlelib/WidgetRedirector.py

#	count	content
1	n/a	from tkinter import *
2	n/a
3	n/a	class WidgetRedirector:
4	n/a
5	n/a	"""Support for redirecting arbitrary widget subcommands.
6	n/a
7	n/a	Some Tk operations don't normally pass through Tkinter. For example, if a
8	n/a	character is inserted into a Text widget by pressing a key, a default Tk
9	n/a	binding to the widget's 'insert' operation is activated, and the Tk library
10	n/a	processes the insert without calling back into Tkinter.
11	n/a
12	n/a	Although a binding to <Key> could be made via Tkinter, what we really want
13	n/a	to do is to hook the Tk 'insert' operation itself.
14	n/a
15	n/a	When a widget is instantiated, a Tcl command is created whose name is the
16	n/a	same as the pathname widget._w. This command is used to invoke the various
17	n/a	widget operations, e.g. insert (for a Text widget). We are going to hook
18	n/a	this command and provide a facility ('register') to intercept the widget
19	n/a	operation.
20	n/a
21	n/a	In IDLE, the function being registered provides access to the top of a
22	n/a	Percolator chain. At the bottom of the chain is a call to the original
23	n/a	Tk widget operation.
24	n/a
25	n/a	"""
26	n/a	def __init__(self, widget):
27	n/a	self._operations = {}
28	n/a	self.widget = widget # widget instance
29	n/a	self.tk = tk = widget.tk # widget's root
30	n/a	w = widget._w # widget's (full) Tk pathname
31	n/a	self.orig = w + "_orig"
32	n/a	# Rename the Tcl command within Tcl:
33	n/a	tk.call("rename", w, self.orig)
34	n/a	# Create a new Tcl command whose name is the widget's pathname, and
35	n/a	# whose action is to dispatch on the operation passed to the widget:
36	n/a	tk.createcommand(w, self.dispatch)
37	n/a
38	n/a	def __repr__(self):
39	n/a	return "WidgetRedirector(%s<%s>)" % (self.widget.__class__.__name__,
40	n/a	self.widget._w)
41	n/a
42	n/a	def close(self):
43	n/a	for operation in list(self._operations):
44	n/a	self.unregister(operation)
45	n/a	widget = self.widget; del self.widget
46	n/a	orig = self.orig; del self.orig
47	n/a	tk = widget.tk
48	n/a	w = widget._w
49	n/a	tk.deletecommand(w)
50	n/a	# restore the original widget Tcl command:
51	n/a	tk.call("rename", orig, w)
52	n/a
53	n/a	def register(self, operation, function):
54	n/a	self._operations[operation] = function
55	n/a	setattr(self.widget, operation, function)
56	n/a	return OriginalCommand(self, operation)
57	n/a
58	n/a	def unregister(self, operation):
59	n/a	if operation in self._operations:
60	n/a	function = self._operations[operation]
61	n/a	del self._operations[operation]
62	n/a	if hasattr(self.widget, operation):
63	n/a	delattr(self.widget, operation)
64	n/a	return function
65	n/a	else:
66	n/a	return None
67	n/a
68	n/a	def dispatch(self, operation, *args):
69	n/a	'''Callback from Tcl which runs when the widget is referenced.
70	n/a
71	n/a	If an operation has been registered in self._operations, apply the
72	n/a	associated function to the args passed into Tcl. Otherwise, pass the
73	n/a	operation through to Tk via the original Tcl function.
74	n/a
75	n/a	Note that if a registered function is called, the operation is not
76	n/a	passed through to Tk. Apply the function returned by self.register()
77	n/a	to *args to accomplish that. For an example, see ColorDelegator.py.
78	n/a
79	n/a	'''
80	n/a	m = self._operations.get(operation)
81	n/a	try:
82	n/a	if m:
83	n/a	return m(*args)
84	n/a	else:
85	n/a	return self.tk.call((self.orig, operation) + args)
86	n/a	except TclError:
87	n/a	return ""
88	n/a
89	n/a
90	n/a	class OriginalCommand:
91	n/a
92	n/a	def __init__(self, redir, operation):
93	n/a	self.redir = redir
94	n/a	self.operation = operation
95	n/a	self.tk = redir.tk
96	n/a	self.orig = redir.orig
97	n/a	self.tk_call = self.tk.call
98	n/a	self.orig_and_operation = (self.orig, self.operation)
99	n/a
100	n/a	def __repr__(self):
101	n/a	return "OriginalCommand(%r, %r)" % (self.redir, self.operation)
102	n/a
103	n/a	def __call__(self, *args):
104	n/a	return self.tk_call(self.orig_and_operation + args)
105	n/a
106	n/a
107	n/a	def main():
108	n/a	root = Tk()
109	n/a	root.wm_protocol("WM_DELETE_WINDOW", root.quit)
110	n/a	text = Text()
111	n/a	text.pack()
112	n/a	text.focus_set()
113	n/a	redir = WidgetRedirector(text)
114	n/a	global previous_tcl_fcn
115	n/a	def my_insert(*args):
116	n/a	print("insert", args)
117	n/a	previous_tcl_fcn(*args)
118	n/a	previous_tcl_fcn = redir.register("insert", my_insert)
119	n/a	root.mainloop()
120	n/a	redir.unregister("insert") # runs after first 'close window'
121	n/a	redir.close()
122	n/a	root.mainloop()
123	n/a	root.destroy()
124	n/a
125	n/a	if __name__ == "__main__":
126	n/a	main()