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ZG dd deZdS )zSynchronization primitives.LockEvent Condition SemaphoreBoundedSemaphore N )compat)events)futures) coroutinec @ s( e Zd ZdZdd Zdd Zdd ZdS ) _ContextManagera Context manager.
This enables the following idiom for acquiring and releasing a
lock around a block:
with (yield from lock):
while failing loudly when accidentally using:
with lock:
c C s
|| _ d S )N)_lock)selflock r %/usr/lib64/python3.6/asyncio/locks.py__init__ s z_ContextManager.__init__c C s d S )Nr )r r r r __enter__ s z_ContextManager.__enter__c G s z| j j W d d | _ X d S )N)r
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S )_ContextManagerMixinc C s t dd S )Nz9"yield from" should be used as context manager expression) RuntimeError)r r r r r , s z _ContextManagerMixin.__enter__c G s d S )Nr )r r r r r r 0 s z _ContextManagerMixin.__exit__c c s | j E d H t| S )N)acquirer )r r r r __iter__5 s z _ContextManagerMixin.__iter__c c s | j E d H t| S )N)r r )r r r r __await__H s z _ContextManagerMixin.__await__c c s | j E d H d S )N)r )r r r r
__aenter__M s z _ContextManagerMixin.__aenter__c C s | j d S )N)r )r exc_typeexctbr r r __aexit__T s z _ContextManagerMixin.__aexit__N) r r r r r r r r ZPY35r r r$ r r r r r + s r c sR e Zd ZdZddddZ fddZdd Zed
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Z S )r a Primitive lock objects.
A primitive lock is a synchronization primitive that is not owned
by a particular coroutine when locked. A primitive lock is in one
of two states, 'locked' or 'unlocked'.
It is created in the unlocked state. It has two basic methods,
acquire() and release(). When the state is unlocked, acquire()
changes the state to locked and returns immediately. When the
state is locked, acquire() blocks until a call to release() in
another coroutine changes it to unlocked, then the acquire() call
resets it to locked and returns. The release() method should only
be called in the locked state; it changes the state to unlocked
and returns immediately. If an attempt is made to release an
unlocked lock, a RuntimeError will be raised.
When more than one coroutine is blocked in acquire() waiting for
the state to turn to unlocked, only one coroutine proceeds when a
release() call resets the state to unlocked; first coroutine which
is blocked in acquire() is being processed.
acquire() is a coroutine and should be called with 'yield from'.
Locks also support the context management protocol. '(yield from lock)'
should be used as the context manager expression.
Usage:
lock = Lock()
...
yield from lock
try:
...
finally:
lock.release()
Context manager usage:
lock = Lock()
...
with (yield from lock):
...
Lock objects can be tested for locking state:
if not lock.locked():
yield from lock
else:
# lock is acquired
...
N)loopc C s. t j | _d| _|d k r || _n
tj | _d S )NF) collectionsdeque_waiters_locked_loopr get_event_loop)r r% r r r r s
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{},waiters:{}z <{} [{}]>r )super__repr__r) r( formatlen)r resextra) __class__r r r0 s
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Lock.__repr__c C s | j S )z Return True if lock is acquired.)r) )r r r r r, s z Lock.lockedc c s | j r&tdd | jD r&d| _ dS | jj }| jj| y"z|E dH W d| jj| X W n& tjk
r | j s~| j Y nX d| _ dS )zAcquire a lock.
This method blocks until the lock is unlocked, then sets it to
locked and returns True.
c s s | ]}|j V qd S )N) cancelled).0wr r r s z Lock.acquire..TN)
r) allr( r*
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z Lock.acquirec C s" | j rd| _ | j ntddS )aG Release a lock.
When the lock is locked, reset it to unlocked, and return.
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There is no return value.
FzLock is not acquired.N)r) r? r )r r r r r s
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r& dS X |j s:|jd dS )z*Wake up the first waiter if it isn't done.NT)nextiterr(
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__classcell__r r )r5 r r Y s 4 c sR e Zd ZdZddddZ fddZdd Zd
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Z S )r a# Asynchronous equivalent to threading.Event.
Class implementing event objects. An event manages a flag that can be set
to true with the set() method and reset to false with the clear() method.
The wait() method blocks until the flag is true. The flag is initially
false.
N)r% c C s. t j | _d| _|d k r || _n
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zEvent.__init__c sD t j }| jrdnd}| jr0dj|t| j}dj|dd |S )NsetZunsetz
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zEvent.__repr__c C s | j S )z5Return True if and only if the internal flag is true.)rG )r r r r is_set s z Event.is_setc C s2 | j s.d| _ x | jD ]}|j s|jd qW dS )zSet the internal flag to true. All coroutines waiting for it to
become true are awakened. Coroutine that call wait() once the flag is
true will not block at all.
TN)rG r( rD rE )r r@ r r r rH s
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d| _ dS )zReset the internal flag to false. Subsequently, coroutines calling
wait() will block until set() is called to set the internal flag
to true again.FN)rG )r r r r clear s z Event.clearc c sB | j r
dS | jj }| jj| z|E dH dS | jj| X dS )zBlock until the internal flag is true.
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TN)rG r* r; r( r< r= )r r@ r r r wait
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Z S )r a Asynchronous equivalent to threading.Condition.
This class implements condition variable objects. A condition variable
allows one or more coroutines to wait until they are notified by another
coroutine.
A new Lock object is created and used as the underlying lock.
N)r% c C sp |d k r|| _ n
tj | _ |d kr0t| j d}n|j | j k rDtd|| _|j| _|j| _|j| _t j
| _ d S )N)r% z"loop argument must agree with lock) r* r r+ r
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zCondition.__init__c sF t j }| j rdnd}| jr2dj|t| j}dj|dd |S )Nr, r- z
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zCondition.__repr__c c s | j std| j z8| jj }| jj| z|E dH dS | jj| X W dd}x4y| j E dH P W qX t j
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X dS )a Wait until notified.
If the calling coroutine has not acquired the lock when this
method is called, a RuntimeError is raised.
This method releases the underlying lock, and then blocks
until it is awakened by a notify() or notify_all() call for
the same condition variable in another coroutine. Once
awakened, it re-acquires the lock and returns True.
z cannot wait on un-acquired lockNTF) r, r r r* r; r( r< r= r r
r> )r r@ r6 r r r rK E s&
zCondition.waitc c s( | }x |s"| j E dH | }qW |S )zWait until a predicate becomes true.
The predicate should be a callable which result will be
interpreted as a boolean value. The final predicate value is
the return value.
N)rK )r Z predicateresultr r r wait_fork s
zCondition.wait_forr c C sL | j stdd}x2| jD ](}||kr*P |j s |d7 }|jd q W dS )a By default, wake up one coroutine waiting on this condition, if any.
If the calling coroutine has not acquired the lock when this method
is called, a RuntimeError is raised.
This method wakes up at most n of the coroutines waiting for the
condition variable; it is a no-op if no coroutines are waiting.
Note: an awakened coroutine does not actually return from its
wait() call until it can reacquire the lock. Since notify() does
not release the lock, its caller should.
z!cannot notify on un-acquired lockr r FN)r, r r( rD rE )r nidxr@ r r r notifyy s zCondition.notifyc C s | j t| j dS )a Wake up all threads waiting on this condition. This method acts
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calling thread has not acquired the lock when this method is called,
a RuntimeError is raised.
N)rQ r2 r( )r r r r
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Z S )r a A Semaphore implementation.
A semaphore manages an internal counter which is decremented by each
acquire() call and incremented by each release() call. The counter
can never go below zero; when acquire() finds that it is zero, it blocks,
waiting until some other thread calls release().
Semaphores also support the context management protocol.
The optional argument gives the initial value for the internal
counter; it defaults to 1. If the value given is less than 0,
ValueError is raised.
r N)r% c C s> |dk rt d|| _tj | _|d k r0|| _n
tj | _d S )Nr z$Semaphore initial value must be >= 0)rL rG r& r' r( r* r r+ )r valuer% r r r r s
zSemaphore.__init__c sN t j }| j rdn
dj| j}| jr:dj|t| j}dj|dd |S )Nr, zunlocked,value:{}z
{},waiters:{}z <{} [{}]>r r. )r/ r0 r, r1 rG r( r2 )r r3 r4 )r5 r r r0 s
zSemaphore.__repr__c C s0 x*| j r*| j j }|j s|jd d S qW d S )N)r( popleftrD rE )r Zwaiterr r r
_wake_up_next s
zSemaphore._wake_up_nextc C s
| j dkS )z:Returns True if semaphore can not be acquired immediately.r )rG )r r r r r, s zSemaphore.lockedc c sz xf| j dkrf| jj }| jj| y|E dH W q |j | j dkr\|j r\| j Y qX qW | j d8 _ dS )a5 Acquire a semaphore.
If the internal counter is larger than zero on entry,
decrement it by one and return True immediately. If it is
zero on entry, block, waiting until some other coroutine has
called release() to make it larger than 0, and then return
True.
r Nr T)rG r* r; r( r< Zcancelr6 rU )r r@ r r r r s
zSemaphore.acquirec C s | j d7 _ | j dS )zRelease a semaphore, incrementing the internal counter by one.
When it was zero on entry and another coroutine is waiting for it to
become larger than zero again, wake up that coroutine.
r N)rG rU )r r r r r s zSemaphore.release)r ) r r r r r r0 rU r, r r r rF r r )r5 r r s
c s4 e Zd ZdZd dd fdd Z fddZ ZS )
r zA bounded semaphore implementation.
This raises ValueError in release() if it would increase the value
above the initial value.
r N)r% c s || _ t j||d d S )N)r% ) _bound_valuer/ r )r rS r% )r5 r r r s zBoundedSemaphore.__init__c s" | j | jkrtdt j d S )Nz(BoundedSemaphore released too many times)rG rV rL r/ r )r )r5 r r r s zBoundedSemaphore.release)r )r r r r r r rF r r )r5 r r s )r __all__r& r r r
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coroutinesr r r r r r r r r r r r s . ByM