Edit File: contextlib.cpython-36.pyc
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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 )r r r r � _recreate_cm$ s z ContextDecorator._recreate_cmc s t � �� �fdd��}|S )Nc s �j � � � | |�S Q R X d S )N)r! )�args�kwds)�funcr r r �inner1 s z(ContextDecorator.__call__.<locals>.inner)r )r r$ r% r )r$ r r �__call__0 s zContextDecorator.__call__N)r r r r r! r& r r r r r ! s c @ s0 e Zd ZdZdd� Zdd� Zdd� Zdd � Zd S ) �_GeneratorContextManagerz%Helper for @contextmanager decorator.c C sJ |||�| _ ||| | _| _| _t|dd �}|d kr@t| �j}|| _d S )Nr )�genr$ r" r# �getattr�typer )r r$ r" r# �docr r r �__init__; s z!_GeneratorContextManager.__init__c C s | j | j| j| j�S )N)� __class__r$ r" r# )r r r r r! 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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> c s t � | |�S )N)r' )r" r# )r$ r r �helper� s z contextmanager.<locals>.helper)r )r$ r8 r )r$ r r � s c @ s( e Zd ZdZdd� Zdd� Zdd� ZdS ) r a2 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() c C s || _ d S )N)�thing)r r9 r r r r, � s zclosing.__init__c C s | j S )N)r9 )r r r r r � s zclosing.__enter__c G s | j j� d S )N)r9 �close)r r5 r r r r � s zclosing.__exit__N)r r r r r, r r r r r r r � s c @ s( e Zd ZdZdd� Zdd� Zdd� ZdS )�_RedirectStreamNc C s || _ g | _d S )N)� _new_target� _old_targets)r � new_targetr r r r, � s z_RedirectStream.__init__c C s* | j jtt| j�� tt| j| j� | jS )N)r= �appendr) r4 �_stream�setattrr< )r r r r r � s z_RedirectStream.__enter__c C s t t| j| jj� � d S )N)rA r4 r@ r= �pop)r �exctype�excinst�exctbr r r r � s z_RedirectStream.__exit__)r r r r@ r, r r r r r r r; � s r; c @ s e Zd ZdZdZdS )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)r r r r r@ r r r r r � s c @ s e Zd ZdZdZdS )r zCContext manager for temporarily redirecting stderr to another file.�stderrN)r r r r r@ r r r r r � s c @ s( e Zd ZdZdd� Zdd� Zdd� ZdS ) r a? 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 G s || _ d S )N)� _exceptions)r � exceptionsr r r r, � s zsuppress.__init__c C s d S )Nr )r r r r r � s zsuppress.__enter__c C s |d k ot || j�S )N)� issubclassrH )r rC rD rE r r r r � s zsuppress.__exit__N)r r r r r, r r r r r r r � s c @ sP e Zd ZdZdd� Zdd� Zdd� Zdd � Zd d � Zd d � Z dd� Z dd� Z dS )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 C s t � | _d S )N)r �_exit_callbacks)r r r r r, s zExitStack.__init__c C s t | �� }| j|_t� | _|S )z?Preserve the context stack by transferring it to a new instance)r* rK r )r � new_stackr r r �pop_all s zExitStack.pop_allc s" � �fdd�}� |_ | j|� dS )z:Helper to correctly register callbacks to __exit__ methodsc s �� f| �� S )Nr )� exc_details)�cm�cm_exitr r � _exit_wrapper s z.ExitStack._push_cm_exit.<locals>._exit_wrapperN)�__self__�push)r rO rP rQ r )rO rP r � _push_cm_exit s zExitStack._push_cm_exitc C sD t |�}y |j}W n tk r2 | jj|� Y nX | j||� |S )a Registers a callback with the standard __exit__ method signature Can suppress exceptions the same way __exit__ methods can. Also accepts any object with an __exit__ method (registering a call to the method instead of the object itself) )r* r �AttributeErrorrK r? rT )r �exit�_cb_type� exit_methodr r r rS s zExitStack.pushc s$ � ��fdd�}�|_ | j|� �S )z\Registers an arbitrary callback and arguments. Cannot suppress exceptions. c s �� �� d S )Nr )r r7 �tb)r" �callbackr# r r rQ 9 s z)ExitStack.callback.<locals>._exit_wrapper)� __wrapped__rS )r rZ r" r# rQ r )r" rZ r# r rZ 4 s zExitStack.callbackc C s( t |�}|j}|j|�}| 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. )r* r r rT )r rO �_cm_type�_exit�resultr r r � enter_contextA s zExitStack.enter_contextc C s | j ddd� dS )z$Immediately unwind the context stackN)r )r r r r r: N s zExitStack.closec s� |d d k }t j� d � � fdd�}d}d}x\| jr�| jj� }y||� rTd}d}d}W q. t j� }||d |d � d}|}Y q.X q.W |r�y|d j}|d �W n tk r� ||d _� Y nX |o�|S )Nr r1 c s8 x,| j }||krd S |d ks$|� kr&P |} qW || _ d S )N)� __context__)�new_exc�old_exc� exc_context)� frame_excr r �_fix_exception_contextX s z2ExitStack.__exit__.<locals>._fix_exception_contextFT)NNN)r4 r5 rK rB r` � BaseException) r rN � received_excre �suppressed_exc� pending_raise�cb�new_exc_details� fixed_ctxr )rd r r R s2 zExitStack.__exit__N) r r r r r, rM rT rS rZ r_ r: r r r r r r s )r r r4 r � collectionsr � functoolsr �__all__�ABCr �objectr r' r r r; r r r r r r r r �<module> s$ I"
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