/usr/lib/python2.7/dist-packages/trollius/queues.py is in python-trollius 1.0.1-1.
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 | """Queues"""
__all__ = ['Queue', 'PriorityQueue', 'LifoQueue', 'JoinableQueue',
'QueueFull', 'QueueEmpty']
import collections
import heapq
from . import events
from . import futures
from . import locks
from .coroutines import coroutine, From, Return
class QueueEmpty(Exception):
'Exception raised by Queue.get(block=0)/get_nowait().'
pass
class QueueFull(Exception):
'Exception raised by Queue.put(block=0)/put_nowait().'
pass
class Queue(object):
"""A queue, useful for coordinating producer and consumer coroutines.
If maxsize is less than or equal to zero, the queue size is infinite. If it
is an integer greater than 0, then "yield From(put())" will block when the
queue reaches maxsize, until an item is removed by get().
Unlike the standard library Queue, you can reliably know this Queue's size
with qsize(), since your single-threaded trollius application won't be
interrupted between calling qsize() and doing an operation on the Queue.
"""
def __init__(self, maxsize=0, loop=None):
if loop is None:
self._loop = events.get_event_loop()
else:
self._loop = loop
self._maxsize = maxsize
# Futures.
self._getters = collections.deque()
# Pairs of (item, Future).
self._putters = collections.deque()
self._init(maxsize)
def _init(self, maxsize):
self._queue = collections.deque()
def _get(self):
return self._queue.popleft()
def _put(self, item):
self._queue.append(item)
def __repr__(self):
return '<{0} at {1:#x} {2}>'.format(
type(self).__name__, id(self), self._format())
def __str__(self):
return '<{0} {1}>'.format(type(self).__name__, self._format())
def _format(self):
result = 'maxsize={0!r}'.format(self._maxsize)
if getattr(self, '_queue', None):
result += ' _queue={0!r}'.format(list(self._queue))
if self._getters:
result += ' _getters[{0}]'.format(len(self._getters))
if self._putters:
result += ' _putters[{0}]'.format(len(self._putters))
return result
def _consume_done_getters(self):
# Delete waiters at the head of the get() queue who've timed out.
while self._getters and self._getters[0].done():
self._getters.popleft()
def _consume_done_putters(self):
# Delete waiters at the head of the put() queue who've timed out.
while self._putters and self._putters[0][1].done():
self._putters.popleft()
def qsize(self):
"""Number of items in the queue."""
return len(self._queue)
@property
def maxsize(self):
"""Number of items allowed in the queue."""
return self._maxsize
def empty(self):
"""Return True if the queue is empty, False otherwise."""
return not self._queue
def full(self):
"""Return True if there are maxsize items in the queue.
Note: if the Queue was initialized with maxsize=0 (the default),
then full() is never True.
"""
if self._maxsize <= 0:
return False
else:
return self.qsize() >= self._maxsize
@coroutine
def put(self, item):
"""Put an item into the queue.
If you yield From(put()), wait until a free slot is available
before adding item.
"""
self._consume_done_getters()
if self._getters:
assert not self._queue, (
'queue non-empty, why are getters waiting?')
getter = self._getters.popleft()
# Use _put and _get instead of passing item straight to getter, in
# case a subclass has logic that must run (e.g. JoinableQueue).
self._put(item)
getter.set_result(self._get())
elif self._maxsize > 0 and self._maxsize <= self.qsize():
waiter = futures.Future(loop=self._loop)
self._putters.append((item, waiter))
yield From(waiter)
else:
self._put(item)
def put_nowait(self, item):
"""Put an item into the queue without blocking.
If no free slot is immediately available, raise QueueFull.
"""
self._consume_done_getters()
if self._getters:
assert not self._queue, (
'queue non-empty, why are getters waiting?')
getter = self._getters.popleft()
# Use _put and _get instead of passing item straight to getter, in
# case a subclass has logic that must run (e.g. JoinableQueue).
self._put(item)
getter.set_result(self._get())
elif self._maxsize > 0 and self._maxsize <= self.qsize():
raise QueueFull
else:
self._put(item)
@coroutine
def get(self):
"""Remove and return an item from the queue.
If you yield From(get()), wait until a item is available.
"""
self._consume_done_putters()
if self._putters:
assert self.full(), 'queue not full, why are putters waiting?'
item, putter = self._putters.popleft()
self._put(item)
# When a getter runs and frees up a slot so this putter can
# run, we need to defer the put for a tick to ensure that
# getters and putters alternate perfectly. See
# ChannelTest.test_wait.
self._loop.call_soon(putter._set_result_unless_cancelled, None)
raise Return(self._get())
elif self.qsize():
raise Return(self._get())
else:
waiter = futures.Future(loop=self._loop)
self._getters.append(waiter)
result = yield From(waiter)
raise Return(result)
def get_nowait(self):
"""Remove and return an item from the queue.
Return an item if one is immediately available, else raise QueueEmpty.
"""
self._consume_done_putters()
if self._putters:
assert self.full(), 'queue not full, why are putters waiting?'
item, putter = self._putters.popleft()
self._put(item)
# Wake putter on next tick.
putter.set_result(None)
return self._get()
elif self.qsize():
return self._get()
else:
raise QueueEmpty
class PriorityQueue(Queue):
"""A subclass of Queue; retrieves entries in priority order (lowest first).
Entries are typically tuples of the form: (priority number, data).
"""
def _init(self, maxsize):
self._queue = []
def _put(self, item, heappush=heapq.heappush):
heappush(self._queue, item)
def _get(self, heappop=heapq.heappop):
return heappop(self._queue)
class LifoQueue(Queue):
"""A subclass of Queue that retrieves most recently added entries first."""
def _init(self, maxsize):
self._queue = []
def _put(self, item):
self._queue.append(item)
def _get(self):
return self._queue.pop()
class JoinableQueue(Queue):
"""A subclass of Queue with task_done() and join() methods."""
def __init__(self, maxsize=0, loop=None):
super(JoinableQueue, self).__init__(maxsize=maxsize, loop=loop)
self._unfinished_tasks = 0
self._finished = locks.Event(loop=self._loop)
self._finished.set()
def _format(self):
result = Queue._format(self)
if self._unfinished_tasks:
result += ' tasks={0}'.format(self._unfinished_tasks)
return result
def _put(self, item):
super(JoinableQueue, self)._put(item)
self._unfinished_tasks += 1
self._finished.clear()
def task_done(self):
"""Indicate that a formerly enqueued task is complete.
Used by queue consumers. For each get() used to fetch a task,
a subsequent call to task_done() tells the queue that the processing
on the task is complete.
If a join() is currently blocking, it will resume when all items have
been processed (meaning that a task_done() call was received for every
item that had been put() into the queue).
Raises ValueError if called more times than there were items placed in
the queue.
"""
if self._unfinished_tasks <= 0:
raise ValueError('task_done() called too many times')
self._unfinished_tasks -= 1
if self._unfinished_tasks == 0:
self._finished.set()
@coroutine
def join(self):
"""Block until all items in the queue have been gotten and processed.
The count of unfinished tasks goes up whenever an item is added to the
queue. The count goes down whenever a consumer thread calls task_done()
to indicate that the item was retrieved and all work on it is complete.
When the count of unfinished tasks drops to zero, join() unblocks.
"""
if self._unfinished_tasks > 0:
yield From(self._finished.wait())
|