Python code coverage for Lib/idlelib/redirector.py

#	count	content
1	n/a	from tkinter import TclError
2	n/a
3	n/a	class WidgetRedirector:
4	n/a	"""Support for redirecting arbitrary widget subcommands.
5	n/a
6	n/a	Some Tk operations don't normally pass through tkinter. For example, if a
7	n/a	character is inserted into a Text widget by pressing a key, a default Tk
8	n/a	binding to the widget's 'insert' operation is activated, and the Tk library
9	n/a	processes the insert without calling back into tkinter.
10	n/a
11	n/a	Although a binding to <Key> could be made via tkinter, what we really want
12	n/a	to do is to hook the Tk 'insert' operation itself. For one thing, we want
13	n/a	a text.insert call in idle code to have the same effect as a key press.
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. We will also intercept method calls on the tkinter class
20	n/a	instance that represents the tk widget.
21	n/a
22	n/a	In IDLE, WidgetRedirector is used in Percolator to intercept Text
23	n/a	commands. The function being registered provides access to the top
24	n/a	of a Percolator chain. At the bottom of the chain is a call to the
25	n/a	original Tk widget operation.
26	n/a	"""
27	n/a	def __init__(self, widget):
28	n/a	'''Initialize attributes and setup redirection.
29	n/a
30	n/a	_operations: dict mapping operation name to new function.
31	n/a	widget: the widget whose tcl command is to be intercepted.
32	n/a	tk: widget.tk, a convenience attribute, probably not needed.
33	n/a	orig: new name of the original tcl command.
34	n/a
35	n/a	Since renaming to orig fails with TclError when orig already
36	n/a	exists, only one WidgetDirector can exist for a given widget.
37	n/a	'''
38	n/a	self._operations = {}
39	n/a	self.widget = widget # widget instance
40	n/a	self.tk = tk = widget.tk # widget's root
41	n/a	w = widget._w # widget's (full) Tk pathname
42	n/a	self.orig = w + "_orig"
43	n/a	# Rename the Tcl command within Tcl:
44	n/a	tk.call("rename", w, self.orig)
45	n/a	# Create a new Tcl command whose name is the widget's pathname, and
46	n/a	# whose action is to dispatch on the operation passed to the widget:
47	n/a	tk.createcommand(w, self.dispatch)
48	n/a
49	n/a	def __repr__(self):
50	n/a	return "%s(%s<%s>)" % (self.__class__.__name__,
51	n/a	self.widget.__class__.__name__,
52	n/a	self.widget._w)
53	n/a
54	n/a	def close(self):
55	n/a	"Unregister operations and revert redirection created by .__init__."
56	n/a	for operation in list(self._operations):
57	n/a	self.unregister(operation)
58	n/a	widget = self.widget
59	n/a	tk = widget.tk
60	n/a	w = widget._w
61	n/a	# Restore the original widget Tcl command.
62	n/a	tk.deletecommand(w)
63	n/a	tk.call("rename", self.orig, w)
64	n/a	del self.widget, self.tk # Should not be needed
65	n/a	# if instance is deleted after close, as in Percolator.
66	n/a
67	n/a	def register(self, operation, function):
68	n/a	'''Return OriginalCommand(operation) after registering function.
69	n/a
70	n/a	Registration adds an operation: function pair to ._operations.
71	n/a	It also adds a widget function attribute that masks the tkinter
72	n/a	class instance method. Method masking operates independently
73	n/a	from command dispatch.
74	n/a
75	n/a	If a second function is registered for the same operation, the
76	n/a	first function is replaced in both places.
77	n/a	'''
78	n/a	self._operations[operation] = function
79	n/a	setattr(self.widget, operation, function)
80	n/a	return OriginalCommand(self, operation)
81	n/a
82	n/a	def unregister(self, operation):
83	n/a	'''Return the function for the operation, or None.
84	n/a
85	n/a	Deleting the instance attribute unmasks the class attribute.
86	n/a	'''
87	n/a	if operation in self._operations:
88	n/a	function = self._operations[operation]
89	n/a	del self._operations[operation]
90	n/a	try:
91	n/a	delattr(self.widget, operation)
92	n/a	except AttributeError:
93	n/a	pass
94	n/a	return function
95	n/a	else:
96	n/a	return None
97	n/a
98	n/a	def dispatch(self, operation, *args):
99	n/a	'''Callback from Tcl which runs when the widget is referenced.
100	n/a
101	n/a	If an operation has been registered in self._operations, apply the
102	n/a	associated function to the args passed into Tcl. Otherwise, pass the
103	n/a	operation through to Tk via the original Tcl function.
104	n/a
105	n/a	Note that if a registered function is called, the operation is not
106	n/a	passed through to Tk. Apply the function returned by self.register()
107	n/a	to *args to accomplish that. For an example, see colorizer.py.
108	n/a
109	n/a	'''
110	n/a	m = self._operations.get(operation)
111	n/a	try:
112	n/a	if m:
113	n/a	return m(*args)
114	n/a	else:
115	n/a	return self.tk.call((self.orig, operation) + args)
116	n/a	except TclError:
117	n/a	return ""
118	n/a
119	n/a
120	n/a	class OriginalCommand:
121	n/a	'''Callable for original tk command that has been redirected.
122	n/a
123	n/a	Returned by .register; can be used in the function registered.
124	n/a	redir = WidgetRedirector(text)
125	n/a	def my_insert(*args):
126	n/a	print("insert", args)
127	n/a	original_insert(*args)
128	n/a	original_insert = redir.register("insert", my_insert)
129	n/a	'''
130	n/a
131	n/a	def __init__(self, redir, operation):
132	n/a	'''Create .tk_call and .orig_and_operation for .__call__ method.
133	n/a
134	n/a	.redir and .operation store the input args for __repr__.
135	n/a	.tk and .orig copy attributes of .redir (probably not needed).
136	n/a	'''
137	n/a	self.redir = redir
138	n/a	self.operation = operation
139	n/a	self.tk = redir.tk # redundant with self.redir
140	n/a	self.orig = redir.orig # redundant with self.redir
141	n/a	# These two could be deleted after checking recipient code.
142	n/a	self.tk_call = redir.tk.call
143	n/a	self.orig_and_operation = (redir.orig, operation)
144	n/a
145	n/a	def __repr__(self):
146	n/a	return "%s(%r, %r)" % (self.__class__.__name__,
147	n/a	self.redir, self.operation)
148	n/a
149	n/a	def __call__(self, *args):
150	n/a	return self.tk_call(self.orig_and_operation + args)
151	n/a
152	n/a
153	n/a	def _widget_redirector(parent): # htest #
154	n/a	from tkinter import Toplevel, Text
155	n/a
156	n/a	top = Toplevel(parent)
157	n/a	top.title("Test WidgetRedirector")
158	n/a	x, y = map(int, parent.geometry().split('+')[1:])
159	n/a	top.geometry("+%d+%d" % (x, y + 175))
160	n/a	text = Text(top)
161	n/a	text.pack()
162	n/a	text.focus_set()
163	n/a	redir = WidgetRedirector(text)
164	n/a	def my_insert(*args):
165	n/a	print("insert", args)
166	n/a	original_insert(*args)
167	n/a	original_insert = redir.register("insert", my_insert)
168	n/a
169	n/a	if __name__ == "__main__":
170	n/a	import unittest
171	n/a	unittest.main('idlelib.idle_test.test_redirector',
172	n/a	verbosity=2, exit=False)
173	n/a
174	n/a	from idlelib.idle_test.htest import run
175	n/a	run(_widget_redirector)