B

��{a�\�@s^
dZd
dl
Z
d
dlZd
dlZd
dlmZ
d
dlmZ
ddddd	d
ddd
dddgZGdd	�d	e
j	�Z
Gdd
�d
e
j	�ZGdd�de�Z
Gdd�d�ZGdd�dee
e
�ZGdd�dee�Zdd�Zdd�ZGdd�de
�ZGdd�de
�ZGdd�de�ZGd d�de�ZGd!d�de
�ZGd"d#�d#�ZGd$d
�d
ee
�ZGd%d�dee�ZGd&d�de
�ZdS)'z4Utilities for with-statement contexts.  See PEP 343.�N)
�deque)
�wraps�asynccontextmanager�contextmanager�closing�nullcontext�AbstractContextManager�AbstractAsyncContextManager�AsyncExitStack�ContextDecorator�	ExitStack�redirect_stdout�redirect_stderr�suppressc@s2eZ
dZd
Zdd�Zejdd��
Zedd��
Z	dS)	rz,An abstract base class for context managers.c


Cs|S)
z0Return `self` upon entering the runtime context.�)
�selfrr� /usr/lib/python3.7/contextlib.py�	__enter__sz AbstractContextManager.__enter__c
Csd
S)z9Raise any exception triggered within the runtime context.Nr)r�exc_type�	exc_value�	tracebackrrr�__exit__szAbstractContextManager.__exit__cCs|tkrt
�|
d
d�StS)Nrr)r�_collections_abc�_check_methods�NotImplemented)�cls�
Crrr�__subclasshook__s

z'AbstractContextManager.__subclasshook__N)
�__name__�
__module__�__qualname__�__doc__r�abc�abstractmethodr�classmethodrrrrrrsc@s2eZ
dZd
Zdd�Zejdd��
Zedd��
Z	dS)	r	z9An abstract base class for asynchronous context managers.c


�s|S)
z0Return `self` upon entering the runtime context.r)
rrrr�
__aenter__&sz&AbstractAsyncContextManager.__aenter__c
�sd
S)z9Raise any exception triggered within the runtime context.Nr)rrrrrrr�	__aexit__*sz%AbstractAsyncContextManager.__aexit__cCs|tkrt
�|
d
d�StS)Nr%r&)r	rrr)rrrrrr/s


z,AbstractAsyncContextManager.__subclasshook__N)
rrr r!r%r"r#r&r$rrrrrr	"sc@s eZ
dZd
Zdd�Zdd�ZdS)rzJA base class or mixin that enables context managers to work as decorators.c


Cs|S)
a6
Return a recreated instance of self.

        Allows an otherwise one-shot context manager like
        _GeneratorContextManager to support use as
        a decorator via implicit recreation.

        This is a private interface just for _GeneratorContextManager.
        See issue #11647 for details.
        r)
rrrr�_recreate_cm:s
zContextDecorator._recreate_cmcst��
��
fd
d��
}|S)Nc	s�
���
�||
�
SQRXdS)
N)
r')�args�kwds)�funcrrr�innerGs

z(ContextDecorator.__call__.<locals>.inner)
r)rr*r+r)r*rr�__call__Fs
zContextDecorator.__call__N)rrr r!r'r,rrrrr7s
c@seZ
dZd
Zdd�ZdS)�_GeneratorContextManagerBasezBShared functionality for @contextmanager and @asynccontextmanager.cCsJ|
||�
|_|
|||_
|_|_t|
d
d�}|dkr@t|�
j}||_dS)Nr!)�genr*r(r)�getattr�typer!)rr*r(r)�docrrr�__init__Qs





z%_GeneratorContextManagerBase.__init__N)rrr r!r2rrrrr-Ns
r-c@s(eZ
dZd
Zdd�Zdd�Zdd�ZdS)	�_GeneratorContextManagerz%Helper for @contextmanager decorator.c

Cs|�|j
|j|j�S)
N)�	__class__r*r(r))
rrrrr'esz%_GeneratorContextManager._recreate_cmc

Cs:|`|`
|`y
t|j�
Stk
r4


td
�
d�YnXdS)Nzgenerator didn't yield)r(r)r*�nextr.�
StopIteration�RuntimeError)
rrrrrks





z"_GeneratorContextManager.__enter__c
Cs�|
dkr6yt|j
�

Wntk
r*


d
SXtd�
�
n�|dkrD|
�}y|j
�|
||�
Wn�tk
r~
}
z||k	Sd}~XYnftk
r�
}
z(||kr�d
S|
tkr�|j|kr�d
S�Wdd}~XYn"


t��d|kr�d
S�YnXtd�
�
dS)NFzgenerator didn't stop�
z#generator didn't stop after throw())r5r.r6r7�throw�	__cause__�sys�exc_info)rr0�valuer�excrrrrts.
















z!_GeneratorContextManager.__exit__N)rrr r!r'rrrrrrr3`s	r3c@s eZ
dZd
Zdd�Zdd�ZdS)�_AsyncGeneratorContextManagerz Helper for @asynccontextmanager.c

�s4y|j�
�IdHStk
r.


td
�
d�YnXdS)Nzgenerator didn't yield)r.�	__anext__�StopAsyncIterationr7)
rrrrr%�s



z(_AsyncGeneratorContextManager.__aenter__c
�s
|
dkr<y|j�
�IdH
Wntk
r0


dSXtd
�
�
n�|dkrJ|
�}y"|j�|
||�IdH
td�
�
Wn�tk
r�
}
z||k	Sd}~XYnztk
r�
}
z.||kr�dSt|ttf�r�|j|kr�dS�Wdd}~XYn0tk
�
r

}
z||k	�r��Wdd}~XYnXdS)Nzgenerator didn't stopz#generator didn't stop after throw()F)	r.r@rAr7�athrow�
isinstancer6r:�
BaseException)r�typr=rr>rrrr&�s.





















z'_AsyncGeneratorContextManager.__aexit__N)rrr r!r%r&rrrrr?�sr?c
st��
�f
d
d��
}
|
S)a�
@contextmanager decorator.

    Typical usage:

        @contextmanager
        def some_generator(<arguments>):
            <setup>
            try:
                yield <value>
            finally:
                <cleanup>

    This makes this:

        with some_generator(<arguments>) as <variable>:
            <body>

    equivalent to this:

        <setup>
        try:
            <variable> = <value>
            <body>
        finally:
            <cleanup>
    cst�||
�S)
N)
r3)r(r))
r*rr�helper�szcontextmanager.<locals>.helper)
r)r*rFr)
r*rr�sc
st��
�f
d
d��
}
|
S)a�
@asynccontextmanager decorator.

    Typical usage:

        @asynccontextmanager
        async def some_async_generator(<arguments>):
            <setup>
            try:
                yield <value>
            finally:
                <cleanup>

    This makes this:

        async with some_async_generator(<arguments>) as <variable>:
            <body>

    equivalent to this:

        <setup>
        try:
            <variable> = <value>
            <body>
        finally:
            <cleanup>
    cst�||
�S)
N)
r?)r(r))
r*rrrF
sz#asynccontextmanager.<locals>.helper)
r)r*rFr)
r*rr�sc@s(eZ
dZd
Zdd�Zdd�Zdd�ZdS)	ra2
Context to automatically close something at the end of a block.

    Code like this:

        with closing(<module>.open(<arguments>)) as f:
            <block>

    is equivalent to this:

        f = <module>.open(<arguments>)
        try:
            <block>
        finally:
            f.close()

    cCs
|
|_dS)
N)
�thing)rrGrrrr2%
s
zclosing.__init__c


Cs|jS)
N)
rG)
rrrrr'
s
zclosing.__enter__c
Gs|j�
�
dS)
N)rG�close)rr<rrrr)
s
zclosing.__exit__N)rrr r!r2rrrrrrr
s
c@s(eZ
dZd
Zdd�Zdd�Zdd�Zd
S)�_RedirectStreamNcCs|
|_g|_
dS)
N)�_new_target�_old_targets)r�
new_targetrrrr21
s
z_RedirectStream.__init__c

Cs*|j�
tt|j��

tt|j|j�
|jS)
N)rK�appendr/r;�_stream�setattrrJ)
rrrrr6
s


z_RedirectStream.__enter__cCstt
|j|j���
dS)
N)rOr;rNrK�pop)r�exctype�excinst�exctbrrrr;
s
z_RedirectStream.__exit__)rrr rNr2rrrrrrrI-
srIc
@seZ
dZd
ZdZdS)r
aA
Context manager for temporarily redirecting stdout to another file.

        # How to send help() to stderr
        with redirect_stdout(sys.stderr):
            help(dir)

        # How to write help() to a file
        with open('help.txt', 'w') as f:
            with redirect_stdout(f):
                help(pow)
    �stdoutN)rrr r!rNrrrrr
?
sc
@seZ
dZd
ZdZdS)rzCContext manager for temporarily redirecting stderr to another file.�stderrN)rrr r!rNrrrrrO
s
c@s(eZ
dZd
Zdd�Zdd�Zdd�ZdS)	ra?
Context manager to suppress specified exceptions

    After the exception is suppressed, execution proceeds with the next
    statement following the with statement.

         with suppress(FileNotFoundError):
             os.remove(somefile)
         # Execution still resumes here if the file was already removed
    c
Gs
|
|_dS)
N)
�_exceptions)r�
exceptionsrrrr2`
s
zsuppress.__init__c


CsdS)
Nr)
rrrrrc
s
zsuppress.__enter__cCs|
dk	ot|
|j
�S)
N)�
issubclassrV)rrQrRrSrrrrf
s
zsuppress.__exit__N)rrr r!r2rrrrrrrU
s	c@sbeZ
dZd
Zedd��
Zedd��
Zdd�Zdd	�Zd
d�Z	dd
�Z
dd�Zdd�Zddd�
Z
dS)�_BaseExitStackz.A base class for ExitStack and AsyncExitStack.cs��
fd
d�}|S)Ncs�
�||
|�S)
Nr)rr>�tb)�cm�cm_exitrr�
_exit_wrapperx
s
z:_BaseExitStack._create_exit_wrapper.<locals>._exit_wrapperr)r[r\r]r)r[r\r�_create_exit_wrapperv
sz#_BaseExitStack._create_exit_wrapperc
s��
�fd
d�}|S)Ncs�
���

dS)
Nr)rr>rZ)r(�callbackr)rrr]~
s
z8_BaseExitStack._create_cb_wrapper.<locals>._exit_wrapperr)r_r(r)r]r)r(r_r)r�_create_cb_wrapper|
sz!_BaseExitStack._create_cb_wrapperc

Cst�|_
dS)
N)r�_exit_callbacks)
rrrrr2�
s
z_BaseExitStack.__init__c
Cst|�
�}
|j
|
_
t�|_
|
S)
z@Preserve the context stack by transferring it to a new instance.)r0rar)r�	new_stackrrr�pop_all�
s



z_BaseExitStack.pop_allcCsBt|
�
}y
|j
}Wntk
r0


|�|
�

YnX|�|
|�
|
S)
a
Registers a callback with the standard __exit__ method signature.

        Can suppress exceptions the same way __exit__ method can.
        Also accepts any object with an __exit__ method (registering a call
        to the method instead of the object itself).
        )r0r�AttributeError�_push_exit_callback�
_push_cm_exit)r�exit�_cb_type�exit_methodrrr�push�
s	



z_BaseExitStack.pushcCs(t|
�
}|j
}|�|
�
}|�|
|�
|S)
z�Enters the supplied context manager.

        If successful, also pushes its __exit__ method as a callback and
        returns the result of the __enter__ method.
        )r0rrrf)rr[�_cm_type�_exit�resultrrr�
enter_context�
s





z_BaseExitStack.enter_contextcOs&|j|
f
|�|�
}|
|_
|�|�

|
S)
z\Registers an arbitrary callback and arguments.

        Cannot suppress exceptions.
        )r`�__wrapped__re)rr_r(r)r]rrrr_�
s


z_BaseExitStack.callbackcCs"|�|
|�}|
|_
|�|d
�
dS)z;Helper to correctly register callbacks to __exit__ methods.TN)r^�__self__re)rr[r\r]rrrrf�
s

z_BaseExitStack._push_cm_exitTcCs|j�
||
f�

dS)
N)rarM)rr_�is_syncrrrre�
s
z"_BaseExitStack._push_exit_callbackN)
T)rrr r!�staticmethodr^r`r2rcrjrnr_rfrerrrrrYs
s

rYc@s(eZ
dZd
Zdd�Zdd�Zdd�ZdS)	ra�
Context manager for dynamic management of a stack of exit callbacks.

    For example:
        with ExitStack() as stack:
            files = [stack.enter_context(open(fname)) for fname in filenames]
            # All opened files will automatically be closed at the end of
            # the with statement, even if attempts to open files later
            # in the list raise an exception.
    c


Cs|S)
Nr)
rrrrr�
s
zExitStack.__enter__c

s�|
d
dk	}t�
�d��f
dd�}d}d}xh|jr�|j��\}}|sJt�
y||
�r`d}d}d}
Wq.


t�
�}||d|
d�
d}|}
Yq.Xq.W|r�y|
dj}	|
d�
Wn tk
r�


|	|
d_�YnX|o�|S)Nr
r8cs8x,|j}||
krdS|dks$|�kr&P|}qW|
|_dS)
N)
�__context__)�new_exc�old_exc�exc_context)
�	frame_excrr�_fix_exception_context�
s




z2ExitStack.__exit__.<locals>._fix_exception_contextFT)NNN)r;r<rarP�AssertionErrorrsrD)
r�exc_details�received_excrx�suppressed_exc�
pending_raiserq�cb�new_exc_details�	fixed_ctxr)
rwrr�
s4























zExitStack.__exit__c

Cs|�d
d
d
�
d
S)z%Immediately unwind the context stack.N)
r)
rrrrrHszExitStack.closeN)rrr r!rrrHrrrrr�
s	1c@s`eZ
dZd
Zedd��
Zedd��
Zdd�Zdd	�Zd
d�Z	dd
�Z
dd�Zdd�Zdd�Z
dS)r
a�
Async context manager for dynamic management of a stack of exit
    callbacks.

    For example:
        async with AsyncExitStack() as stack:
            connections = [await stack.enter_async_context(get_connection())
                for i in range(5)]
            # All opened connections will automatically be released at the
            # end of the async with statement, even if attempts to open a
            # connection later in the list raise an exception.
    cs��
fd
d�}|S)Nc�s�
�||
|�IdHS)
Nr)rr>rZ)r[r\rrr]s
z@AsyncExitStack._create_async_exit_wrapper.<locals>._exit_wrapperr)r[r\r]r)r[r\r�_create_async_exit_wrappersz)AsyncExitStack._create_async_exit_wrapperc
s��
�fd
d�}|S)Nc�s�
���
IdH
dS)
Nr)rr>rZ)r(r_r)rrr] s
z>AsyncExitStack._create_async_cb_wrapper.<locals>._exit_wrapperr)r_r(r)r]r)r(r_r)r�_create_async_cb_wrappersz'AsyncExitStack._create_async_cb_wrapperc�s.t|
�
}|j
}|�|
�
Id
H}|�|
|�
|S)z�Enters the supplied async context manager.

        If successful, also pushes its __aexit__ method as a callback and
        returns the result of the __aenter__ method.
        N)r0r&r%�_push_async_cm_exit)rr[rkrlrmrrr�enter_async_context$s




z"AsyncExitStack.enter_async_contextcCsDt|
�
}y
|j
}Wn tk
r2


|�|
d
�
YnX|�|
|�
|
S)a#
Registers a coroutine function with the standard __aexit__ method
        signature.

        Can suppress exceptions the same way __aexit__ method can.
        Also accepts any object with an __aexit__ method (registering a call
        to the method instead of the object itself).
        F)r0r&rdrer�)rrgrhrirrr�push_async_exit0s




zAsyncExitStack.push_async_exitcOs(|j|
f
|�|�
}|
|_
|�|d
�
|
S)zfRegisters an arbitrary coroutine function and arguments.

        Cannot suppress exceptions.
        F)r�rore)rr_r(r)r]rrr�push_async_callbackBs

z"AsyncExitStack.push_async_callbackc

�s|�d
d
d
�Id
H
d
S)z%Immediately unwind the context stack.N)
r&)
rrrr�acloseOszAsyncExitStack.aclosecCs"|�|
|�}|
|_
|�|d
�
dS)zLHelper to correctly register coroutine function to __aexit__
        method.FN)r�rpre)rr[r\r]rrrr�Ss

z"AsyncExitStack._push_async_cm_exitc


�s|S)
Nr)
rrrrr%Zs
zAsyncExitStack.__aenter__c
�s�|
d
dk	}t�
�d��f
dd�}d}d}xx|jr�|j��\}}y0|rR||
�}n||
�IdH}|rpd}d}d}
Wq.


t�
�}	||	d|
d�
d}|	}
Yq.Xq.W|r�y|
dj}
|
d�
Wn tk
r�


|
|
d_�YnX|o�|S)Nr
r8cs8x,|j}||
krdS|dks$|�kr&P|}qW|
|_dS)
N)
rs)rtrurv)
rwrrrxcs




z8AsyncExitStack.__aexit__.<locals>._fix_exception_contextFT)NNN)r;r<rarPrsrD)rrzr{rxr|r}rqr~�cb_suppressrr�r)
rwrr&]s8
























zAsyncExitStack.__aexit__N)rrr r!rrr�r�r�r�r�r�r�r%r&rrrrr
s
c@s*eZ
dZd
Zd	dd�
Zdd�Zdd�ZdS)
raO
Context manager that does no additional processing.

    Used as a stand-in for a normal context manager, when a particular
    block of code is only sometimes used with a normal context manager:

    cm = optional_cm if condition else nullcontext()
    with cm:
        # Perform operation, using optional_cm if condition is True
    NcCs
|
|_dS)
N)
�enter_result)rr�rrrr2�s
znullcontext.__init__c


Cs|jS)
N)
r�)
rrrrr�s
znullcontext.__enter__c

GsdS)
Nr)r�excinforrrr�s
znullcontext.__exit__)
N)rrr r!r2rrrrrrr�s	
)r!r"r;r�collectionsr�	functoolsr�__all__�ABCrr	�objectrr-r3r?rrrrIr
rrrYrr
rrrrr�<module>
s<










B
-!!SE