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� e j� e j� dS )z�Support asyncio with serial ports. EXPERIMENTAL
Posix platforms only, Python 3.4+ only.
Windows event loops can not wait for serial ports with the current
implementation. It should be possible to get that working though.
� Nc s� e Zd ZdZ� fdd�Zedd� �Zdd� Zdd � Zd
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dd� Zd:dd�Zdd� Zdd � Zd d � Zd d � Zd!d"� Zd#d$� Zd%d&� Zd'd(� Zd)d*� Zd+d,� Zd;d-d.�Zd<d0d1�Zd2d3� Z d=d4d5�Z d6d7� Z d8d9� Z � Z S )>�SerialTransportug An asyncio transport model of a serial communication channel.
A transport class is an abstraction of a communication channel.
This allows protocol implementations to be developed against the
transport abstraction without needing to know the details of the
underlying channel, such as whether it is a pipe, a socket, or
indeed a serial port.
You generally won’t instantiate a transport yourself; instead, you
will call `create_serial_connection` which will create the
transport and try to initiate the underlying communication channel,
calling you back when it succeeds.
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N)r �_close)r r r r �closeH s zSerialTransport.closec C sX y| j j| j�}W n0 tjk
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j |� | j � dS )z�Write some data to the transport.
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can_write_eofv s z SerialTransport.can_write_eofc C s | j � dS )u� Pause the receiving end of the transport.
No data will be passed to the protocol’s data_received() method
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N)�_remove_reader)r r r r �
pause_reading} s z SerialTransport.pause_readingc C s | j � dS )z�Resume the receiving end of the transport.
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N)r )r r r r �resume_reading� s z SerialTransport.resume_readingNc C s | j ||d� | j� dS )uL Set the high- and low-water limits for write flow control.
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N)�_abort)r r r r �abort� s zSerialTransport.abortc C sl | j � | jkrdS | jshd| _y| jj� W n: tk
rf } z | jjd|| | jd�� W Y dd}~X nX dS )a
To be called whenever the write-buffer size increases.
Tests the current write-buffer size against the high water
mark configured for this transport. If the high water mark is
exceeded, the protocol is instructed to pause_writing().
NTz protocol.pause_writing() failed)�message� exception� transportr )r% � _high_waterr r �
pause_writing� Exceptionr �call_exception_handler)r r r r r r, � s z%SerialTransport._maybe_pause_protocolc C sh | j rd| j� | jkrdd| _ y| jj� W n: tk
rb } z | jjd|| | jd�� W Y dd}~X nX dS )a- To be called whenever the write-buffer size decreases.
Tests the current write-buffer size against the low water
mark configured for this transport. If the write-buffer
size is below the low water mark, the protocol is
instructed that is can resume_writing().
Fz protocol.resume_writing() failed)r; r< r= r N)r r% �
_low_waterr �resume_writingr@ r rA )r r r r r �_maybe_resume_protocol� s z&SerialTransport._maybe_resume_protocolc C s dj | j�}t|�}|s td��| jj� y| jj|�}W nR ttfk
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� s�t�| j� | j� | jr�| j
� r�| j� dS |dks�t�||d� }| jj |� | j� | j�st�dS )a� Asynchronously write buffered data.
This method is called back asynchronously as a writer
registered with the asyncio event-loop against the
underlying file descriptor for the serial port.
Should the write-buffer become empty if this method
is invoked while the transport is closing, the protocol's
connection_lost() method will be called with None as its
argument.
� z Write buffer should not be emptyz%Fatal write error on serial transportNr )�joinr r( r) �clearr r& �BlockingIOError�InterruptedErrorr+ r r r' �_flushed�_remove_writerrD r r r )r r" Z num_bytesr- r r r r � _write_ready� s,
z SerialTransport._write_readyc C s. | j r*| j r*| jj| jj| j� d| _ d S )NT)r
r r Z
add_readerr �fdr$ )r r r r r s z SerialTransport._ensure_readerc C s | j r | jj| jj� d| _ d S )NF)r
r Z
remove_readerr rM )r r r r r/ s z SerialTransport._remove_readerc C s. | j r*| j r*| jj| jj| j� d| _ d S )NT)r r r Z
add_writerr rM rL )r r r r r* s z SerialTransport._ensure_writerc C s | j r | jj| jj� d| _ d S )NF)r r Z
remove_writerr rM )r r r r rK s z SerialTransport._remove_writerc C sd |dkr |dkrdnd| }|dkr,|d }|| ko>dkn sTt d||f ��|| _|| _dS )z&Ensure consistent write-buffer limits.N�@ i � r z*high (%r) must be >= low (%r) must be >= 0i )�
ValueErrorr> rB )r r2 r3 r r r r s z(SerialTransport._set_write_buffer_limits� Fatal error on serial transportc C s& | j j||| | jd�� | j|� dS )z?Report a fatal error to the event-loop and abort the transport.)r; r< r= r N)r rA r r9 )r r r; r r r r' " s z SerialTransport._fatal_errorc C s | j � dkS )z3True if the write buffer is empty, otherwise False.r )r% )r r r r rJ , s zSerialTransport._flushedc C s2 d| _ | j� | j� r.| j� | jj| j|� dS )a� Close the transport gracefully.
If the write buffer is already empty, writing will be
stopped immediately and a call to the protocol's
connection_lost() method scheduled.
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asynchronous writing will continue, and the _write_ready
method will call this _close method again when the
buffer has been flushed completely.
TN)r r/ rJ rK r r �_call_connection_lost)r r r r r r 0 s
zSerialTransport._closec C s* d| _ | j� | j� | jj| j|� dS )aP Close the transport immediately.
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passed exception.
TN)r r/ rK r r rR )r r r r r r9 B s zSerialTransport._abortc C sj | j s
t�| j st�| j s"t�| jj� z| jj|� W d| jj � | jj
� d| _d| _d| _ X dS )z�Close the connection.
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z%SerialTransport._call_connection_lost)NN)NN)rQ )N)!�__name__�
__module__� __qualname__�__doc__r �propertyr r r r r$ r& r. r0 r1 r4 r% r8 r: r, rD rL r r/ r* rK r r' rJ r r9 rR �
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� Zd S ) �Outputc C s& || _ td|� d|j_|jd� d S )Nz port openedFs hello world
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rl z /dev/ttyUSB0i � )Zbaudrate)rX rb r Z Transportr � coroutiner^ rj rU ZProtocolrl rc r �coroZrun_until_completeZ run_foreverr r r r r �<module> s Q#