#include <TTransport.h>

Inheritance diagram for contrail::sandesh::transport::TTransport:

Public Member Functions
virtual	~TTransport ()

virtual bool	isOpen ()

virtual bool	peek ()

virtual void	open ()

virtual void	close ()

int32_t	read (uint8_t *buf, uint32_t len)

virtual int32_t	read_virt (uint8_t *, uint32_t)

int32_t	readAll (uint8_t *buf, uint32_t len)

virtual int32_t	readAll_virt (uint8_t *buf, uint32_t len)

virtual uint32_t	readEnd ()

int	write (const uint8_t *buf, uint32_t len)

virtual int	write_virt (const uint8_t *, uint32_t)

virtual uint32_t	writeEnd ()

virtual void	flush ()

const uint8_t *	borrow (uint8_t buf, uint32_t len)

virtual const uint8_t *	borrow_virt (uint8_t , uint32_t )

void	consume (uint32_t len)

virtual void	consume_virt (uint32_t)

Protected Member Functions
	TTransport ()

Detailed Description

Generic interface for a method of transporting data. A TTransport may be capable of either reading or writing, but not necessarily both.

Definition at line 57 of file TTransport.h.

Constructor & Destructor Documentation

virtual contrail::sandesh::transport::TTransport::~TTransport ( )

inlinevirtual

Virtual deconstructor.

Definition at line 62 of file TTransport.h.

contrail::sandesh::transport::TTransport::TTransport ( )

inlineprotected

Simple constructor.

Definition at line 246 of file TTransport.h.

Member Function Documentation

const uint8_t* contrail::sandesh::transport::TTransport::borrow	(	uint8_t *	buf,
		uint32_t *	len
	)

inline

Attempts to return a pointer to len bytes, possibly copied into buf. Does not consume the bytes read (i.e.: a later read will return the same data). This method is meant to support protocols that need to read variable-length fields. They can attempt to borrow the maximum amount of data that they will need, then consume (see next method) what they actually use. Some transports will not support this method and others will fail occasionally, so protocols must be prepared to use read if borrow fails.

buf A buffer where the data can be stored if needed. If borrow doesn't return buf, then the contents of buf after the call are undefined. This parameter may be NULL to indicate that the caller is not supplying storage, but would like a pointer into an internal buffer, if available.

Parameters

len *len should initially contain the number of bytes to borrow. If borrow succeeds, *len will contain the number of bytes available in the returned pointer. This will be at least what was requested, but may be more if borrow returns a pointer to an internal buffer, rather than buf. If borrow fails, the contents of *len are undefined.

Returns: If the borrow succeeds, return a pointer to the borrowed data. This might be equal to buf, or it might be a pointer into the transport's internal buffers.

Exceptions

TTransportException if an error occurs

Definition at line 216 of file TTransport.h.

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virtual const uint8_t* contrail::sandesh::transport::TTransport::borrow_virt	(	uint8_t *	,
		uint32_t *
	)

inlinevirtual

Reimplemented in contrail::sandesh::transport::TVirtualTransport< TBufferBase >, contrail::sandesh::transport::TVirtualTransport< TFDTransport >, and contrail::sandesh::transport::TVirtualTransport< TMemoryBuffer, TBufferBase >.

Definition at line 220 of file TTransport.h.

virtual void contrail::sandesh::transport::TTransport::close ( )

inlinevirtual

Closes the transport.

Reimplemented in contrail::sandesh::transport::TMemoryBuffer, and contrail::sandesh::transport::TFDTransport.

Definition at line 96 of file TTransport.h.

void contrail::sandesh::transport::TTransport::consume ( uint32_t len )

inline

Remove len bytes from the transport. This should always follow a borrow of at least len bytes, and should always succeed. TODO(dreiss): Is there any transport that could borrow but fail to consume, or that would require a buffer to dump the consumed data?

Parameters

len	How many bytes to consume

Exceptions

TTransportException If an error occurs

Definition at line 233 of file TTransport.h.

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virtual void contrail::sandesh::transport::TTransport::consume_virt ( uint32_t )

inlinevirtual

Reimplemented in contrail::sandesh::transport::TVirtualTransport< TBufferBase >, contrail::sandesh::transport::TVirtualTransport< TFDTransport >, and contrail::sandesh::transport::TVirtualTransport< TMemoryBuffer, TBufferBase >.

Definition at line 237 of file TTransport.h.

virtual void contrail::sandesh::transport::TTransport::flush ( )

inlinevirtual

Flushes any pending data to be written. Typically used with buffered transport mechanisms.

Exceptions

TTransportException if an error occurs

Definition at line 185 of file TTransport.h.

virtual bool contrail::sandesh::transport::TTransport::isOpen ( )

inlinevirtual

Whether this transport is open.

Reimplemented in contrail::sandesh::transport::TMemoryBuffer, and contrail::sandesh::transport::TFDTransport.

Definition at line 67 of file TTransport.h.

virtual void contrail::sandesh::transport::TTransport::open ( )

inlinevirtual

Opens the transport for communications.

Returns: bool Whether the transport was successfully opened

Reimplemented in contrail::sandesh::transport::TMemoryBuffer, and contrail::sandesh::transport::TFDTransport.

Definition at line 88 of file TTransport.h.

virtual bool contrail::sandesh::transport::TTransport::peek ( )

inlinevirtual

Tests whether there is more data to read or if the remote side is still open. By default this is true whenever the transport is open, but implementations should add logic to test for this condition where possible (i.e. on a socket). This is used by a server to check if it should listen for another request.

Reimplemented in contrail::sandesh::transport::TMemoryBuffer.

Definition at line 79 of file TTransport.h.

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int32_t contrail::sandesh::transport::TTransport::read	(	uint8_t *	buf,
		uint32_t	len
	)

inline

Attempt to read up to the specified number of bytes into the string.

Parameters

buf	Reference to the location to write the data
len	How many bytes to read

Returns: How many bytes were actually read, -1 on error

Definition at line 108 of file TTransport.h.

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virtual int32_t contrail::sandesh::transport::TTransport::read_virt	(	uint8_t *	,
		uint32_t
	)

inlinevirtual

Reimplemented in contrail::sandesh::transport::TVirtualTransport< TBufferBase >, contrail::sandesh::transport::TVirtualTransport< TFDTransport >, and contrail::sandesh::transport::TVirtualTransport< TMemoryBuffer, TBufferBase >.

Definition at line 112 of file TTransport.h.

int32_t contrail::sandesh::transport::TTransport::readAll	(	uint8_t *	buf,
		uint32_t	len
	)

inline

Reads the given amount of data in its entirety no matter what.

Parameters

s	Reference to location for read data
len	How many bytes to read

Returns: How many bytes read, which must be equal to size, -1 on error

Definition at line 125 of file TTransport.h.

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virtual int32_t contrail::sandesh::transport::TTransport::readAll_virt	(	uint8_t *	buf,
		uint32_t	len
	)

inlinevirtual

Reimplemented in contrail::sandesh::transport::TVirtualTransport< TBufferBase >, contrail::sandesh::transport::TVirtualTransport< TFDTransport >, and contrail::sandesh::transport::TVirtualTransport< TMemoryBuffer, TBufferBase >.

Definition at line 129 of file TTransport.h.

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virtual uint32_t contrail::sandesh::transport::TTransport::readEnd ( )

inlinevirtual

Called when read is completed. This can be over-ridden to perform a transport-specific action e.g. logging the request to a file

Returns: number of bytes read if available, 0 otherwise.

Reimplemented in contrail::sandesh::transport::TMemoryBuffer.

Definition at line 140 of file TTransport.h.

int contrail::sandesh::transport::TTransport::write	(	const uint8_t *	buf,
		uint32_t	len
	)

inline

Writes the string in its entirety to the buffer.

Note: You must call flush() to ensure the data is actually written, and available to be read back in the future. Destroying a TTransport object does not automatically flush pending data–if you destroy a TTransport object with written but unflushed data, that data may be discarded. Returns 0 on success, non-zero otherwise

Parameters