/usr/lib/python2.6/idlelib/WidgetRedirector.py is in idle-python2.6 2.6.8-1.1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 | from Tkinter import *
class WidgetRedirector:
"""Support for redirecting arbitrary widget subcommands.
Some Tk operations don't normally pass through Tkinter. For example, if a
character is inserted into a Text widget by pressing a key, a default Tk
binding to the widget's 'insert' operation is activated, and the Tk library
processes the insert without calling back into Tkinter.
Although a binding to <Key> could be made via Tkinter, what we really want
to do is to hook the Tk 'insert' operation itself.
When a widget is instantiated, a Tcl command is created whose name is the
same as the pathname widget._w. This command is used to invoke the various
widget operations, e.g. insert (for a Text widget). We are going to hook
this command and provide a facility ('register') to intercept the widget
operation.
In IDLE, the function being registered provides access to the top of a
Percolator chain. At the bottom of the chain is a call to the original
Tk widget operation.
"""
def __init__(self, widget):
self._operations = {}
self.widget = widget # widget instance
self.tk = tk = widget.tk # widget's root
w = widget._w # widget's (full) Tk pathname
self.orig = w + "_orig"
# Rename the Tcl command within Tcl:
tk.call("rename", w, self.orig)
# Create a new Tcl command whose name is the widget's pathname, and
# whose action is to dispatch on the operation passed to the widget:
tk.createcommand(w, self.dispatch)
def __repr__(self):
return "WidgetRedirector(%s<%s>)" % (self.widget.__class__.__name__,
self.widget._w)
def close(self):
for operation in list(self._operations):
self.unregister(operation)
widget = self.widget; del self.widget
orig = self.orig; del self.orig
tk = widget.tk
w = widget._w
tk.deletecommand(w)
# restore the original widget Tcl command:
tk.call("rename", orig, w)
def register(self, operation, function):
self._operations[operation] = function
setattr(self.widget, operation, function)
return OriginalCommand(self, operation)
def unregister(self, operation):
if operation in self._operations:
function = self._operations[operation]
del self._operations[operation]
if hasattr(self.widget, operation):
delattr(self.widget, operation)
return function
else:
return None
def dispatch(self, operation, *args):
'''Callback from Tcl which runs when the widget is referenced.
If an operation has been registered in self._operations, apply the
associated function to the args passed into Tcl. Otherwise, pass the
operation through to Tk via the original Tcl function.
Note that if a registered function is called, the operation is not
passed through to Tk. Apply the function returned by self.register()
to *args to accomplish that. For an example, see ColorDelegator.py.
'''
m = self._operations.get(operation)
try:
if m:
return m(*args)
else:
return self.tk.call((self.orig, operation) + args)
except TclError:
return ""
class OriginalCommand:
def __init__(self, redir, operation):
self.redir = redir
self.operation = operation
self.tk = redir.tk
self.orig = redir.orig
self.tk_call = self.tk.call
self.orig_and_operation = (self.orig, self.operation)
def __repr__(self):
return "OriginalCommand(%r, %r)" % (self.redir, self.operation)
def __call__(self, *args):
return self.tk_call(self.orig_and_operation + args)
def main():
root = Tk()
root.wm_protocol("WM_DELETE_WINDOW", root.quit)
text = Text()
text.pack()
text.focus_set()
redir = WidgetRedirector(text)
global previous_tcl_fcn
def my_insert(*args):
print "insert", args
previous_tcl_fcn(*args)
previous_tcl_fcn = redir.register("insert", my_insert)
root.mainloop()
redir.unregister("insert") # runs after first 'close window'
redir.close()
root.mainloop()
root.destroy()
if __name__ == "__main__":
main()
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