File Like Interface

This is the FLI API for Python. The classes presented here are a thin wrapper of the C API. The C language description of the File Like Interface provides a detailed description of the FLI code and should be consulted for a good overview of this functionality. This section provides the description of the Python interface to this C code.

Classes

class FLInterface

Cython wrapper for the File-Like-Interface

__init__(*args, **kwargs)

classmethod create_buffered(main_ch=None, pool=None)

Helper function to more easily create a simple buffered FLInterface Does not require any internal function, it’s simply limiting the number of options for the user in order to make it more straightforward to make an explicitly buffered FLI

recvh(*args, **kwargs)

Return a new FLI Recv Handle object

sendh(*args, **kwargs)

Return a new FLI Send Handle object

class FLISendH

Sending handle for FLInterfaces. A send handle is needed when sending data. Proper use of a send handle includes creating it (which also opens it for sending), sending data with one or more to the send operations, and closing it once data transmission is complete.

__init__()

When creating a send handle an application may provide a stream channel to be used. If specifying that the main channel is to be used as a stream channel then both sender and receiver must agree to this. Both send and receive handle would need to be specified using the use_main_as_stream_channel in that case.

Parameters

• adapter – An FLI over which to create a send handle.

• stream_channel – Default is None. The sender may supply a stream channel when opening a send handle. If the FLI is created with stream channels, then the value of the argument may be None. If supplied by a user then the main channel of the FLI must exist. If use_main_as_stream_channel is True, this argument must be None.

• use_main_as_stream_channel – Default is False. If True, then both send handle and receive handle must be true. This would indicate that both sender and receiver are agreeing they are the only sender and the only receiver and they wish to use the single main channel as the stream channel. This can be useful in some restricted circumstances but must only be used when there is exactly one sender and one receiver on the FLI.

• timeout – Default is None. None means to block forever. Otherwise the timeout should be some number of seconds to wait for the operation to complete. The operation could timeout when not supplying a stream channel and there is no channel available during the specified amount of time in the manager channel. The timeout provided here also becomes the default timeout when used in the context manager framework.

Returns

An FLI send handle.

close(timeout=None)

When the conversation is complete the send handle should be closed. In the case of a buffered FLI, no data is sent until the send handle is closed. In all cases, closing the send handle indicates the end of the stream for the receiver.

create_fd(buffered=False, chunk_size=0, arg=0, timeout=None)

Opens a writable file-descriptor and returns it.

finalize_fd()

Flushes a file-descriptor and waits until all buffers are written and the file descriptor is closed.

send_bytes(data, arg=0, buffer=False, timeout=None)

When sending bytes it is possible to specify the bytes to be sent. In addition, you may specify a user specified argument or hint to be sent. If buffer is true, then data is not actually sent on this call, but buffered for future call or until the send handle is closed.

class FLIRecvH

Receiving handle for FLInterfaces.

__init__()

If specifying that the main channel is to be used as a stream channel then both sender and receiver must agree to this. Both send and receive handle would need to be specified using the use_main_as_stream_channel in that case.

Parameters

• adapter – An FLI over which to create a send handle.

• stream_channel – Default is None. The receiver may supply a stream channel when opening a receive handle. If the FLI is created with stream channels, then the value of the argument may be None. If supplied by a user then the manager channel of the FLI must exist. If use_main_as_stream_channel is True, this argument must be None.

• use_main_as_stream_channel – Default is False. If True, then both send handle and receive handle must be true. This would indicate that both sender and receiver are agreeing they are the only sender and the only receiver and they wish to use the single main channel as the stream channel. This can be useful in some restricted circumstances but must only be used when there is exactly one sender and one receiver on the FLI.

• timeout – Default is None. None means to block forever. Otherwise the timeout should be some number of seconds to wait for the operation to complete. The operation could timeout when not supplying a stream channel and there is no channel available during the specified amount of time in the manager channel. The timeout provided here also becomes the default timeout when used in the context manager framework.

Returns

An FLI send handle.

create_fd(timeout=None)

Creates a readable file-descriptor and returns it.

finalize_fd()

Flushes a file-descriptor and waits until all buffers are read and the file descriptor is closed.

exception DragonFLIError

The DragonFLIError is an exception that can be caught that explicitly targets those errors generated by the FLI code. The string associated with the exception includes any traceback avaialable from the C level interaction.

__init__(lib_err, msg)

exception FLIEOT

The FLIEOT Exception is used to indicate the end of stream for an FLI conversation. This Exception inherits from EOFError so applications using the FLI may choose to catch EOFError instead.

Exceptions

exception DragonFLIError

The DragonFLIError is an exception that can be caught that explicitly targets those errors generated by the FLI code. The string associated with the exception includes any traceback avaialable from the C level interaction.

__init__(lib_err, msg)

exception FLIEOT

The FLIEOT Exception is used to indicate the end of stream for an FLI conversation. This Exception inherits from EOFError so applications using the FLI may choose to catch EOFError instead.