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https://github.com/python/cpython
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139 lines
4.7 KiB
Python
139 lines
4.7 KiB
Python
"""Switchboard class.
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This class is used to coordinate updates among all Viewers. Every Viewer must
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conform to the following interface:
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- it must include a method called update_yourself() which takes three
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arguments; the red, green, and blue values of the selected color.
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- When a Viewer selects a color and wishes to update all other Views, it
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should call update_views() on the Switchboard object. Note that the
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Viewer typically does *not* update itself before calling update_views(),
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since this would cause it to get updated twice.
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Optionally, Viewers can also implement:
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- save_options() which takes an optiondb (a dictionary). Store into this
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dictionary any values the Viewer wants to save in the persistent
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~/.pynche file. This dictionary is saved using marshal. The namespace
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for the keys is ad-hoc; make sure you don't clobber some other Viewer's
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keys!
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- withdraw() which takes no arguments. This is called when Pynche is
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unmapped. All Viewers should implement this.
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- colordb_changed() which takes a single argument, an instance of
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ColorDB. This is called whenever the color name database is changed and
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gives a chance for the Viewers to do something on those events. See
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ListViewer for details.
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External Viewers are found dynamically. Viewer modules should have names such
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as FooViewer.py. If such a named module has a module global variable called
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ADDTOVIEW and this variable is true, the Viewer will be added dynamically to
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the `View' menu. ADDTOVIEW contains a string which is used as the menu item
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to display the Viewer (one kludge: if the string contains a `%', this is used
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to indicate that the next character will get an underline in the menu,
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otherwise the first character is underlined).
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FooViewer.py should contain a class called FooViewer, and its constructor
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should take two arguments, an instance of Switchboard, and optionally a Tk
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master window.
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"""
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import sys
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import marshal
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class Switchboard:
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def __init__(self, initfile):
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self.__initfile = initfile
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self.__colordb = None
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self.__optiondb = {}
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self.__views = []
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self.__red = 0
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self.__green = 0
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self.__blue = 0
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self.__canceled = 0
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# read the initialization file
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fp = None
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if initfile:
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try:
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try:
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fp = open(initfile, 'rb')
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self.__optiondb = marshal.load(fp)
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if not isinstance(self.__optiondb, dict):
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print('Problem reading options from file:', initfile,
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file=sys.stderr)
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self.__optiondb = {}
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except (IOError, EOFError, ValueError):
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pass
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finally:
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if fp:
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fp.close()
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def add_view(self, view):
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self.__views.append(view)
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def update_views(self, red, green, blue):
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self.__red = red
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self.__green = green
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self.__blue = blue
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for v in self.__views:
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v.update_yourself(red, green, blue)
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def update_views_current(self):
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self.update_views(self.__red, self.__green, self.__blue)
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def current_rgb(self):
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return self.__red, self.__green, self.__blue
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def colordb(self):
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return self.__colordb
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def set_colordb(self, colordb):
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self.__colordb = colordb
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for v in self.__views:
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if hasattr(v, 'colordb_changed'):
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v.colordb_changed(colordb)
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self.update_views_current()
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def optiondb(self):
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return self.__optiondb
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def save_views(self):
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# save the current color
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self.__optiondb['RED'] = self.__red
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self.__optiondb['GREEN'] = self.__green
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self.__optiondb['BLUE'] = self.__blue
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for v in self.__views:
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if hasattr(v, 'save_options'):
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v.save_options(self.__optiondb)
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# save the name of the file used for the color database. we'll try to
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# load this first.
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self.__optiondb['DBFILE'] = self.__colordb.filename()
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fp = None
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try:
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try:
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fp = open(self.__initfile, 'wb')
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except IOError:
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print('Cannot write options to file:', \
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self.__initfile, file=sys.stderr)
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else:
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marshal.dump(self.__optiondb, fp)
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finally:
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if fp:
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fp.close()
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def withdraw_views(self):
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for v in self.__views:
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if hasattr(v, 'withdraw'):
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v.withdraw()
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def canceled(self, flag=1):
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self.__canceled = flag
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def canceled_p(self):
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return self.__canceled
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