/usr/share/pyshared/nwss/protoutils.py is in python-nwsserver 2.0.0-2.
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 | #
# Copyright (c) 2005-2009, REvolution Computing, Inc.
#
# NetWorkSpaces 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307
# USA
#
"""Miscellaneous utilities and building blocks for the NWS protocol."""
from twisted.python import log
import nwss
import os
_MIN_LONG_VALUE_SIZE = 64
_BUFFER_SIZE = 16 * 1024
_DEBUG = nwss.config.is_debug_enabled('NWS:protoutils')
try:
set() #pylint: disable-msg=W8302
except NameError:
from sets import Set as set #pylint: disable-msg=W0622
class WsNameMap(object):
"""'External-to-internal' name mapping for workspaces. This was separated
into a mixin so that it can be used in DummyConnection as well."""
def __init__(self):
"""Create a new ext-to-int workspace name mapping."""
self.__ext_to_int_names = {}
def get(self, ext_name):
"""Lookup the internal name for an external workspace name. Returns
None if the named workspace doesn't exist."""
return self.__ext_to_int_names.get(ext_name)
def set(self, ext_name, int_name):
"""Set the internal name for an external workspace name."""
self.__ext_to_int_names[ext_name] = int_name
def remove(self, ext_name):
"""Clear the mapping for an internal name for a given external
workspace name. No error is raised if the name didn't exist."""
try:
del self.__ext_to_int_names[ext_name]
except KeyError:
pass
class WsTracker(object):
"""List of 'owned' workspaces, tracked by internal name. Separated into a
mixin so that it can be used in DummyConnection as well."""
def __init__(self):
"""Create a new owned workspace list."""
self.__owned_workspaces = set()
def add(self, int_name):
"""Add a workspace to our ownership list."""
self.__owned_workspaces.add(int_name)
def remove(self, int_name):
"""Remove a workspace from our ownership list."""
try:
self.__owned_workspaces.remove(int_name)
return True
except KeyError:
return False
def contains(self, int_name):
"""Check if we claim ownership of a given workspace."""
return (int_name in self.__owned_workspaces)
def as_list(self):
"""Get a list of workspaces owned by us."""
return list(self.__owned_workspaces)
def get_count(self):
"""Get a count of the workspaces owned by us."""
return len(self.__owned_workspaces)
count = property(get_count)
def clear(self):
"""Clear all workspaces from our list."""
self.__owned_workspaces.clear()
class CountedReceiver(object):
"""Protocol helper class for protocol atoms which consist of a fixed-length
ASCII decimal byte count followed by raw data. Most data in the NWS
protocol adheres to this format with either a 4-byte or 20-byte count.
Generally, this class is used from a protocol object as:
return CountedReceiver(self, self.set_my_value).start, 4
"""
def __init__(self, conn, target, start_count=4):
"""Create a new CountedReceiver protocol atom.
Parameters:
conn - the protocol object on whose behalf we act
target - function to receive the data
start_count - size of count (in bytes) [default: 4]
"""
self.__conn = conn
self.__target = target
self.start_count = start_count
def get_target(self):
"""Get the target of this protocol helper."""
return self.__target
target = property(get_target)
def get_connection(self):
"""Get the Protocol object for this protocol helper."""
return self.__conn
connection = property(get_connection)
def start(self, data):
"""The start state for this atom. This is the method to pass to
twisted as the handler for the chunk of data on a newly created atom.
"""
try:
length = int(data)
if length < 0:
raise ValueError('negative argument length')
except ValueError:
log.msg("error: got bad data from client")
self.__conn.transport.loseConnection()
return None
return self.__target, length
class CountedReceiverLong(CountedReceiver):
"""Specialized protocol helper class for protocol atoms identical to those
supported by CountedReceiver, with a count occupying 20 bytes. The
important difference is that this atom supports saving large data directly
to a file. As a result, the 'target' must support an optional boolean
argument 'long_data'. If True, the data passed to the target will be a
filename, rather than the data itself.
Generally, this class is used from a protocol object as:
return CountedReceiverLong(self, self.set_my_value).start, 20
"""
def __init__(self, conn, target):
"""Create a new CountedReceiverLong protocol atom.
Parameters:
conn - the protocol object on whose behalf we act
target - function to receive the data
"""
CountedReceiver.__init__(self, conn, target, 20)
self.__target = target
self.__conn = conn
self.__file = None
self.__filename = None
self.__remain_length = 0
def start(self, data):
"""The start state for this atom. This is the method to pass to
twisted as the handler for the chunk of data on a newly created atom.
"""
base_next = CountedReceiver.start(self, data)
if base_next is None:
return None
_, length = base_next
# Compute the threshold for treating the value as long data
threshold = max(_MIN_LONG_VALUE_SIZE, nwss.config.nwsLongValueSize)
if length >= threshold:
# Set up the streaming transfer
self.__remain_length = length
tmpfile = self.__conn.new_long_arg_file()
if tmpfile == None:
# Failed to create the file, but still need to ride out the
# transfer.
self.__file = None
else:
self.__file, self.__filename = tmpfile
return self.long_data, min(_BUFFER_SIZE, length)
else:
return base_next
def long_data(self, data):
"""The streaming data state for this atom. This state is entered only
if the length of the data exceeds the long-data threshold, and will be
re-entered repeatedly until all data has been read.
"""
self.__remain_length -= len(data)
if self.__file != None:
self.__file.write(data)
if self.__remain_length <= 0:
self.__file.close()
return self.__target(self.__filename, long_data=True)
else:
if self.__remain_length <= 0:
self.__conn.send_error('Failed to read long data from the ' +
'filesystem.')
self.__conn.transport.loseConnection()
return None
return self.long_data, min(_BUFFER_SIZE, self.__remain_length)
class NameValueReceiver(object):
"""Specialized protocol helper class for protocol elements consisting of
two consecutive CountedReceiver atoms representing names and values. The
target will receive a (name, value) tuple.
Generally, this class is used from a protocol object as:
return NameValueReceiver(self, self.add_entry).start, 4
"""
start_count = 4
def __init__(self, conn, target):
"""Create a new NameValueReceiver protocol atom.
Parameters:
conn - the protocol object on whose behalf we act
target - function to receive the data
"""
self.__conn = conn
self.__target = target
self.__name = None
def get_start(self):
"""Get the start state for this atom. Note: unlike the preceding
helpers, this is NOT a handler to be passed to twisted, as it needs to
delegate to a counted receiver instead. Thanks to the 'start' property
defined below, however, the notation is the same.
"""
return CountedReceiver(self.__conn, self.name).start
start = property(get_start)
def name(self, data):
"""Target to receive name of name/value pair."""
self.__name = data
return CountedReceiver(self.__conn, self.value).start, 4
def value(self, data):
"""Target to receive value of name/value pair."""
return self.__target((self.__name, data))
class ListReceiver(object):
"""Specialized protocol helper class for protocol elements consisting of a
4-byte ASCII decimal count followed by a series of protocol elements of a
given format.
Two callback functions should be provided. One will be called for each
item in the list, and the other will be called when all items have been
received.
Generally, this class is used from a protocol object as:
return ListReceiver(self,
ItemReceiver,
self.add_item,
self.last_item).start, 4
"""
start_count = 4
def __init__(self, conn, item, target, done):
"""Create a new ListReceiver protocol element.
Parameters:
conn - the protocol object on whose behalf we act
item - item type to read for list
target - function to receive each item
done - function called when all items have been received
"""
self.__conn = conn
self.__target = target
self.__done = done
self.__item_type = item
self.__remaining = 0
def start(self, data):
"""The start state for this atom. This is the method to pass to
twisted as the handler for the chunk of data on a newly created atom.
"""
# Read the length
try:
length = int(data)
if length < 0:
raise ValueError('Negative count for item list.')
except ValueError, exc:
log.msg('Malformed protocol message: %s' % exc.args[0])
self.__conn.transport.loseConnection()
return None
# Start reading the first item
self.__remaining = length
if self.__remaining == 0:
return self.__done()
else:
item = self.__item_type(self.__conn, self.item)
return item.start, item.start_count
def item(self, data, **kwargs):
"""The callback for each item."""
self.__remaining -= 1
self.__target(data, **kwargs)
if self.__remaining == 0:
return self.__done()
else:
item = self.__item_type(self.__conn, self.item)
return item.start, item.start_count
class DictReceiver(ListReceiver):
"""Specialized protocol helper class for protocol elements consisting of a
stream of name-value pairs. The format is that of a ListReceiver receiving
NameValueReceiver elements.
A callback function will receive a dictionary of all name-value pairs once
they have all been read in.
Generally, this class is used from a protocol object as:
return DictReceiver(self, self.set_dictionary).start, 4
or:
dr = DictReceiver(self, self.__receive_connection_options)
return dr.start, dr.start_count
"""
def __init__(self, conn, target):
"""Create a new DictReceiver protocol element.
Parameters:
conn - the protocol object on whose behalf we act
target - function to receive the complete dictionary
"""
ListReceiver.__init__(self,
conn,
NameValueReceiver,
self.entry,
self.finished)
self.__target = target
self.__entries = {}
def entry(self, data):
"""Callback to receive each name, value pair."""
name, value = data
self.__entries[name] = value
def finished(self):
"""Callback upon completion."""
return self.__target(self.__entries)
class ArgTupleReceiver(ListReceiver):
"""Specialized protocol helper class for protocol elements consisting of a
stream of arguments. The format is that of a ListReceiver receiving
CountedReceiverLong elements.
A callback function will receive a list of all arguments once they have all
been read in. The elements of the list will be strings and, for "long"
items, tuples of filename and content length.
Generally, this class is used from a protocol object as:
return ArgTupleReceiver(self, self.set_args).start, 4
or:
atr = ArgTupleReceiver(self, self.set_args)
return atr.start, atr.start_count
"""
def __init__(self, conn, target, metadata):
"""Create a new ArgTupleReceiver protocol element.
Parameters:
conn - the protocol object on whose behalf we act
target - function to receive the complete argument list
metadata - metadata attached to this arg tuple, if any
"""
ListReceiver.__init__(self,
conn,
CountedReceiverLong,
self.next_arg,
self.finished)
self.__target = target
self.__args = []
self.__metadata = metadata
def next_arg(self, data, long_data=False):
"""Callback to receive each argument. If long_data is True, the data
contains a filename rather than directly containing the data."""
if long_data:
dlen = os.stat(data).st_size
data = (data, dlen)
self.__args.append(data)
def finished(self):
"""Callback upon completion."""
return self.__target(self.__args, self.__metadata)
class FileProducer(object):
"""Twisted "producer" to allow drawing data directly from a file on
disk."""
def __init__(self, value, transport):
"""Create a new file producer for a given value object.
Parameters:
value - the value
transport - consumer of data
"""
self.__value = value
self.__file = value.get_file()
self.__buffer_size = _BUFFER_SIZE
self.__transport = transport
self.__finished = False
def stopProducing(self):
#pylint: disable-msg=C0103
"""Implementation of IPushProducer.stopProducing method from Twisted.
Called to abort production of data from the file."""
if _DEBUG:
log.msg('stopProducing called')
if not self.__finished:
if _DEBUG:
log.msg('stopProducing unregistering producer')
try:
self.__file.close()
except (KeyboardInterrupt, SystemExit):
raise
except Exception: #pylint: disable-msg=W0703
pass
self.__transport.unregisterProducer()
self.__finished = True
self.__value.access_complete()
else:
log.msg("error: stopProducing called even though I finished")
def resumeProducing(self):
#pylint: disable-msg=C0103
"""Implementation of IPushProducer.resumeProducing method from Twisted.
Called to resume production of data from the file after it has been
paused."""
# read some more data from the file, a write it to the transport
if _DEBUG:
log.msg('resumeProducing called')
if not self.__finished:
if _DEBUG:
log.msg('resumeProducing reading file')
data = self.__file.read(self.__buffer_size)
if not data:
if _DEBUG:
log.msg('resumeProducing unregistering producer')
try:
self.__file.close()
except (KeyboardInterrupt, SystemExit):
raise
except Exception: #pylint: disable-msg=W0703
pass
self.__transport.unregisterProducer()
self.__finished = True
self.__value.access_complete()
else:
if _DEBUG:
log.msg('resumeProducing sending data to client ' + data)
self.__transport.write(data)
else:
log.msg("error: resumeProducing called even though I unregistered")
def pauseProducing(self):
#pylint: disable-msg=C0103,R0201
"""Implementation of IPushProducer.pauseProducing method from Twisted.
Called to resume production of data from the file after it has been
paused. Even though this method does nothing, it must be present in
order for this class to implement the IPushProducer interface."""
if _DEBUG:
log.msg('pauseProducing called')
def map_proto_generator(data):
"""Utility which turns a map into a stream of name value pairs in the
correct protocol form for metadata maps."""
return [('%04d%s%04d%s' % (len(k), k, len(v), v)) for k, v in data.items()]
|