/usr/share/system-config-printer/ppdcache.py is in system-config-printer-gnome 1.5.7+20160212-0ubuntu2.
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 | #!/usr/bin/python3
## Copyright (C) 2010, 2011, 2012, 2013, 2014 Red Hat, Inc.
## Authors:
## Tim Waugh <twaugh@redhat.com>
## This program is free software; you can redistribute it and/or modify
## it under the terms of the GNU General Public License as published by
## the Free Software Foundation; either version 2 of the License, or
## (at your option) any later version.
## This program is distributed in the hope that it will be useful,
## but WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
## GNU General Public License for more details.
## You should have received a copy of the GNU General Public License
## along with this program; if not, write to the Free Software
## Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
import asyncconn
import cups
from gi.repository import GLib
from gi.repository import Gdk
from gi.repository import Gtk
import os
from shutil import copyfileobj
from tempfile import NamedTemporaryFile
from debug import *
cups.require ("1.9.50")
class PPDCache:
def __init__ (self, host=None, port=None, encryption=None):
self._cups = None
self._exc = None
self._cache = dict()
self._modtimes = dict()
self._host = host
self._port = port
self._encryption = encryption
self._queued = list()
self._connecting = False
debugprint ("+%s" % self)
def __del__ (self):
debugprint ("-%s" % self)
if self._cups:
self._cups.destroy ()
def fetch_ppd (self, name, callback, check_uptodate=True):
if check_uptodate and name in self._modtimes:
# We have getPPD3 so we can check whether the PPD is up to
# date.
debugprint ("%s: check if %s is up to date" % (self, name))
self._cups.getPPD3 (name,
modtime=self._modtimes[name],
reply_handler=lambda c, r:
self._got_ppd3 (c, name, r, callback),
error_handler=lambda c, r:
self._got_ppd3 (c, name, r, callback))
return
try:
f = self._cache[name]
except RuntimeError as e:
self._schedule_callback (callback, name, None, e)
return
except KeyError:
if not self._cups:
self._queued.append ((name, callback))
if not self._connecting:
self._connect ()
return
debugprint ("%s: fetch PPD for %s" % (self, name))
self._cups.getPPD3 (name,
reply_handler=lambda c, r:
self._got_ppd3 (c, name, r, callback),
error_handler=lambda c, r:
self._got_ppd3 (c, name, r, callback))
return
# Copy from our file object to a new temporary file, create a
# PPD object from it, then remove the file. This way we don't
# leave temporary files around even though we are caching...
f.seek (0)
with NamedTemporaryFile () as tmpf:
copyfileobj (f, tmpf)
try:
ppd = cups.PPD (tmpf.file)
self._schedule_callback (callback, name, ppd, None)
except Exception as e:
self._schedule_callback (callback, name, None, e)
def _connect (self, callback=None):
self._connecting = True
asyncconn.Connection (host=self._host, port=self._port,
encryption=self._encryption,
reply_handler=self._connected,
error_handler=self._connected)
def _got_ppd (self, connection, name, result, callback):
if isinstance (result, Exception):
self._schedule_callback (callback, name, none, result)
else:
# Store an open file object, then remove the actual file.
# This way we don't leave temporary files around.
try:
self._cache[name] = open (result, "rb")
debugprint ("%s: caching %s (fd %d)" %
(self, result,
self._cache[name].fileno()))
os.unlink (result)
except IOError as exc:
self._schedule_callback (callback, name, None, exc)
return
self.fetch_ppd (name, callback)
def _got_ppd3 (self, connection, name, result, callback):
(status, modtime, filename) = result
if status in [cups.HTTP_OK, cups.HTTP_NOT_MODIFIED]:
if status == cups.HTTP_NOT_MODIFIED:
# The file is no newer than the one we already have.
# CUPS before 1.5.3 created a temporary file in error
# in this situation (STR #4018) so remove that.
try:
os.unlink (filename)
except OSError:
pass
elif status == cups.HTTP_OK:
# Our version of the file was older. Cache the new version.
# Store an open file object, then remove the actual
# file. This way we don't leave temporary files
# around.
try:
self._cache[name] = open (filename, "rb")
debugprint ("%s: caching %s (fd %d) "
"(%s) - %s" % (self, filename,
self._cache[name].fileno (),
modtime, status))
os.unlink (filename)
self._modtimes[name] = modtime
except IOError as exc:
# File disappeared?
debugprint ("%s: file %s disappeared? Unable to cache it"
% (self, filename))
self._schedule_callback (callback, name, None, exc)
return
# Now fetch it from our own cache.
self.fetch_ppd (name, callback, check_uptodate=False)
else:
self._schedule_callback (callback, name,
None, cups.HTTPError (status))
def _connected (self, connection, exc):
self._connecting = False
if isinstance (exc, Exception):
self._cups = None
self._exc = exc
else:
self._cups = connection
queued = self._queued
self._queued = list()
for name, callback in queued:
self.fetch_ppd (name, callback)
def _schedule_callback (self, callback, name, result, exc):
def cb_func (callback, name, result, exc):
Gdk.threads_enter ()
callback (name, result, exc)
Gdk.threads_leave ()
return False
GLib.idle_add (cb_func, callback, name, result, exc)
if __name__ == "__main__":
import sys
from debug import *
from gi.repository import GObject
set_debugging (True)
Gdk.threads_init ()
loop = GObject.MainLoop ()
def signal (name, result, exc):
debugprint ("**** %s" % name)
debugprint (repr (result))
debugprint (repr (exc))
c = cups.Connection ()
printers = c.getPrinters ()
del c
cache = PPDCache ()
p = None
for p in printers:
cache.fetch_ppd (p, signal)
if p:
GLib.timeout_add_seconds (1, cache.fetch_ppd, p, signal)
GLib.timeout_add_seconds (5, loop.quit)
loop.run ()
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