/usr/lib/python2.7/dist-packages/gevent/_threading.py is in python-gevent 1.1.0-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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targets real OS threads. (Unlike 'threading' which flips between
green and OS threads based on whether the monkey patching is in effect
or not).
This module is missing 'Thread' class, but includes 'Queue'.
"""
try:
from Queue import Full, Empty
except ImportError:
from queue import Full, Empty
from collections import deque
import heapq
from time import time as _time, sleep as _sleep
from gevent import monkey
from gevent.hub import PY3
__all__ = ['Condition',
'Event',
'Lock',
'RLock',
'Semaphore',
'BoundedSemaphore',
'Queue',
'local',
'stack_size']
thread_name = '_thread' if PY3 else 'thread'
start_new_thread, Lock, get_ident, local, stack_size = monkey.get_original(thread_name, [
'start_new_thread', 'allocate_lock', 'get_ident', '_local', 'stack_size'])
class RLock(object):
def __init__(self):
self.__block = Lock()
self.__owner = None
self.__count = 0
def __repr__(self):
owner = self.__owner
return "<%s owner=%r count=%d>" % (
self.__class__.__name__, owner, self.__count)
def acquire(self, blocking=1):
me = get_ident()
if self.__owner == me:
self.__count = self.__count + 1
return 1
rc = self.__block.acquire(blocking)
if rc:
self.__owner = me
self.__count = 1
return rc
__enter__ = acquire
def release(self):
if self.__owner != get_ident():
raise RuntimeError("cannot release un-acquired lock")
self.__count = count = self.__count - 1
if not count:
self.__owner = None
self.__block.release()
def __exit__(self, t, v, tb):
self.release()
# Internal methods used by condition variables
def _acquire_restore(self, count_owner):
count, owner = count_owner
self.__block.acquire()
self.__count = count
self.__owner = owner
def _release_save(self):
count = self.__count
self.__count = 0
owner = self.__owner
self.__owner = None
self.__block.release()
return (count, owner)
def _is_owned(self):
return self.__owner == get_ident()
class Condition(object):
def __init__(self, lock=None):
if lock is None:
lock = RLock()
self.__lock = lock
# Export the lock's acquire() and release() methods
self.acquire = lock.acquire
self.release = lock.release
# If the lock defines _release_save() and/or _acquire_restore(),
# these override the default implementations (which just call
# release() and acquire() on the lock). Ditto for _is_owned().
try:
self._release_save = lock._release_save
except AttributeError:
pass
try:
self._acquire_restore = lock._acquire_restore
except AttributeError:
pass
try:
self._is_owned = lock._is_owned
except AttributeError:
pass
self.__waiters = []
def __enter__(self):
return self.__lock.__enter__()
def __exit__(self, *args):
return self.__lock.__exit__(*args)
def __repr__(self):
return "<Condition(%s, %d)>" % (self.__lock, len(self.__waiters))
def _release_save(self):
self.__lock.release() # No state to save
def _acquire_restore(self, x):
self.__lock.acquire() # Ignore saved state
def _is_owned(self):
# Return True if lock is owned by current_thread.
# This method is called only if __lock doesn't have _is_owned().
if self.__lock.acquire(0):
self.__lock.release()
return False
else:
return True
def wait(self, timeout=None):
if not self._is_owned():
raise RuntimeError("cannot wait on un-acquired lock")
waiter = Lock()
waiter.acquire()
self.__waiters.append(waiter)
saved_state = self._release_save()
try: # restore state no matter what (e.g., KeyboardInterrupt)
if timeout is None:
waiter.acquire()
else:
# Balancing act: We can't afford a pure busy loop, so we
# have to sleep; but if we sleep the whole timeout time,
# we'll be unresponsive. The scheme here sleeps very
# little at first, longer as time goes on, but never longer
# than 20 times per second (or the timeout time remaining).
endtime = _time() + timeout
delay = 0.0005 # 500 us -> initial delay of 1 ms
while True:
gotit = waiter.acquire(0)
if gotit:
break
remaining = endtime - _time()
if remaining <= 0:
break
delay = min(delay * 2, remaining, .05)
_sleep(delay)
if not gotit:
try:
self.__waiters.remove(waiter)
except ValueError:
pass
finally:
self._acquire_restore(saved_state)
def notify(self, n=1):
if not self._is_owned():
raise RuntimeError("cannot notify on un-acquired lock")
__waiters = self.__waiters
waiters = __waiters[:n]
if not waiters:
return
for waiter in waiters:
waiter.release()
try:
__waiters.remove(waiter)
except ValueError:
pass
def notify_all(self):
self.notify(len(self.__waiters))
class Semaphore(object):
# After Tim Peters' semaphore class, but not quite the same (no maximum)
def __init__(self, value=1):
if value < 0:
raise ValueError("semaphore initial value must be >= 0")
self.__cond = Condition(Lock())
self.__value = value
def acquire(self, blocking=1):
rc = False
self.__cond.acquire()
while self.__value == 0:
if not blocking:
break
self.__cond.wait()
else:
self.__value = self.__value - 1
rc = True
self.__cond.release()
return rc
__enter__ = acquire
def release(self):
self.__cond.acquire()
self.__value = self.__value + 1
self.__cond.notify()
self.__cond.release()
def __exit__(self, t, v, tb):
self.release()
class BoundedSemaphore(Semaphore):
"""Semaphore that checks that # releases is <= # acquires"""
def __init__(self, value=1):
Semaphore.__init__(self, value)
self._initial_value = value
def release(self):
if self.Semaphore__value >= self._initial_value:
raise ValueError("Semaphore released too many times")
return Semaphore.release(self)
class Event(object):
# After Tim Peters' event class (without is_posted())
def __init__(self):
self.__cond = Condition(Lock())
self.__flag = False
def _reset_internal_locks(self):
# private! called by Thread._reset_internal_locks by _after_fork()
self.__cond.__init__()
def is_set(self):
return self.__flag
def set(self):
self.__cond.acquire()
try:
self.__flag = True
self.__cond.notify_all()
finally:
self.__cond.release()
def clear(self):
self.__cond.acquire()
try:
self.__flag = False
finally:
self.__cond.release()
def wait(self, timeout=None):
self.__cond.acquire()
try:
if not self.__flag:
self.__cond.wait(timeout)
return self.__flag
finally:
self.__cond.release()
class Queue:
"""Create a queue object with a given maximum size.
If maxsize is <= 0, the queue size is infinite.
"""
def __init__(self, maxsize=0):
self.maxsize = maxsize
self._init(maxsize)
# mutex must be held whenever the queue is mutating. All methods
# that acquire mutex must release it before returning. mutex
# is shared between the three conditions, so acquiring and
# releasing the conditions also acquires and releases mutex.
self.mutex = Lock()
# Notify not_empty whenever an item is added to the queue; a
# thread waiting to get is notified then.
self.not_empty = Condition(self.mutex)
# Notify not_full whenever an item is removed from the queue;
# a thread waiting to put is notified then.
self.not_full = Condition(self.mutex)
# Notify all_tasks_done whenever the number of unfinished tasks
# drops to zero; thread waiting to join() is notified to resume
self.all_tasks_done = Condition(self.mutex)
self.unfinished_tasks = 0
def task_done(self):
"""Indicate that a formerly enqueued task is complete.
Used by Queue consumer threads. 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 a ValueError if called more times than there were items
placed in the queue.
"""
self.all_tasks_done.acquire()
try:
unfinished = self.unfinished_tasks - 1
if unfinished <= 0:
if unfinished < 0:
raise ValueError('task_done() called too many times')
self.all_tasks_done.notify_all()
self.unfinished_tasks = unfinished
finally:
self.all_tasks_done.release()
def join(self):
"""Blocks 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 the item was retrieved and all work on it is complete.
When the count of unfinished tasks drops to zero, join() unblocks.
"""
self.all_tasks_done.acquire()
try:
while self.unfinished_tasks:
self.all_tasks_done.wait()
finally:
self.all_tasks_done.release()
def qsize(self):
"""Return the approximate size of the queue (not reliable!)."""
self.mutex.acquire()
try:
return self._qsize()
finally:
self.mutex.release()
def empty(self):
"""Return True if the queue is empty, False otherwise (not reliable!)."""
self.mutex.acquire()
try:
return not self._qsize()
finally:
self.mutex.release()
def full(self):
"""Return True if the queue is full, False otherwise (not reliable!)."""
self.mutex.acquire()
try:
if self.maxsize <= 0:
return False
if self.maxsize >= self._qsize():
return True
finally:
self.mutex.release()
def put(self, item, block=True, timeout=None):
"""Put an item into the queue.
If optional args 'block' is true and 'timeout' is None (the default),
block if necessary until a free slot is available. If 'timeout' is
a positive number, it blocks at most 'timeout' seconds and raises
the Full exception if no free slot was available within that time.
Otherwise ('block' is false), put an item on the queue if a free slot
is immediately available, else raise the Full exception ('timeout'
is ignored in that case).
"""
self.not_full.acquire()
try:
if self.maxsize > 0:
if not block:
if self._qsize() >= self.maxsize:
raise Full
elif timeout is None:
while self._qsize() >= self.maxsize:
self.not_full.wait()
elif timeout < 0:
raise ValueError("'timeout' must be a positive number")
else:
endtime = _time() + timeout
while self._qsize() >= self.maxsize:
remaining = endtime - _time()
if remaining <= 0.0:
raise Full
self.not_full.wait(remaining)
self._put(item)
self.unfinished_tasks += 1
self.not_empty.notify()
finally:
self.not_full.release()
def put_nowait(self, item):
"""Put an item into the queue without blocking.
Only enqueue the item if a free slot is immediately available.
Otherwise raise the Full exception.
"""
return self.put(item, False)
def get(self, block=True, timeout=None):
"""Remove and return an item from the queue.
If optional args 'block' is true and 'timeout' is None (the default),
block if necessary until an item is available. If 'timeout' is
a positive number, it blocks at most 'timeout' seconds and raises
the Empty exception if no item was available within that time.
Otherwise ('block' is false), return an item if one is immediately
available, else raise the Empty exception ('timeout' is ignored
in that case).
"""
self.not_empty.acquire()
try:
if not block:
if not self._qsize():
raise Empty
elif timeout is None:
while not self._qsize():
self.not_empty.wait()
elif timeout < 0:
raise ValueError("'timeout' must be a positive number")
else:
endtime = _time() + timeout
while not self._qsize():
remaining = endtime - _time()
if remaining <= 0.0:
raise Empty
self.not_empty.wait(remaining)
item = self._get()
self.not_full.notify()
return item
finally:
self.not_empty.release()
def get_nowait(self):
"""Remove and return an item from the queue without blocking.
Only get an item if one is immediately available. Otherwise
raise the Empty exception.
"""
return self.get(False)
# Override these methods to implement other queue organizations
# (e.g. stack or priority queue).
# These will only be called with appropriate locks held
# Initialize the queue representation
def _init(self, maxsize):
self.queue = deque()
def _qsize(self, len=len):
return len(self.queue)
# Put a new item in the queue
def _put(self, item):
self.queue.append(item)
# Get an item from the queue
def _get(self):
return self.queue.popleft()
class PriorityQueue(Queue):
'''Variant of Queue that retrieves open entries in priority order (lowest first).
Entries are typically tuples of the form: (priority number, data).
'''
def _init(self, maxsize):
self.queue = []
def _qsize(self, len=len):
return len(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):
'''Variant of Queue that retrieves most recently added entries first.'''
def _init(self, maxsize):
self.queue = []
def _qsize(self, len=len):
return len(self.queue)
def _put(self, item):
self.queue.append(item)
def _get(self):
return self.queue.pop()
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