LLRP::CConnection Class Reference
[Core LTK Library classes and functions]

LLRP connection class. More...

#include <ltkcpp_connection.h>

List of all members.

Public Member Functions
	CConnection (const CTypeRegistry *pTypeRegistry, unsigned int nBufferSize)
	Construct a new LLRP connection instance.
	~CConnection (void)
	Destruct a LLRP connection instance.
int	openConnectionToReader (const char *pReaderHostName)
	Open the connection to the reader.
const char *	getConnectError (void)
	Get the string that explains openReaderConnection() error.
int	closeConnectionToReader (void)
	Close connection to reader, allow reuse of instance.
CMessage *	transact (CMessage *pSendMessage, int nMaxMS)
	Transact a LLRP request and response to a connection.
const CErrorDetails *	getTransactError (void)
	Get the details that explains transact() error.
EResultCode	sendMessage (CMessage *pMessage)
	Send a LLRP message to a connection.
const CErrorDetails *	getSendError (void)
	Get the details that explains sendMessage() error.
CMessage *	recvMessage (int nMaxMS)
	Receive a message from a connection.
CMessage *	recvResponse (int nMaxMS, const CTypeDescriptor *pResponseType, llrp_u32_t ResponseMessageID)
	Receive a specific message from a connection.
const CErrorDetails *	getRecvError (void)
	Get the details that explains recvMessage() or recvResponse() error.

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Detailed Description

LLRP connection class.

An LLRP connection consists of:

• A network socket
• An input queue of messages already received. Used to hold asynchronous messages while awaiting a response.
• Receiver state.
  • The receive buffer and count
  • Whether a frame is valid. Valid means that the receive buffer holds a frame and the MessageLength, MessageType, ProtocolVersion, and MessageID are valid (usable). Not valid with a nBuffer greater than 0 means that a frame is being received. Sometimes we want to look at the frame after it has been (or attempted to be) decoded.
  • Top-level frame variables: CFrameExtract
  • Details of the last receiver error, including I/O errors, end-of-file (EOF), timeout, or decode errors.
• Send state
  • The send buffer and count
  • Details of the last send error, including I/O errors, or encode errors.

Definition at line 81 of file ltkcpp_connection.h.

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Constructor & Destructor Documentation

LLRP::CConnection::CConnection (  const CTypeRegistry *  pTypeRegistry, unsigned int  nBufferSize )

Construct a new LLRP connection instance. Parameters: [in]  pTypeRegistry  The LLRP registry of known message/parameter types. Includes standard and custom. Used during decode. [in]  nBufferSize  Size of each the receive and send buffers. Use size larger than the largest frame you expect. 0 selects a default value. Returns: !=NULL Pointer to connection instance ==NULL Error, always an allocation failure most likely nBufferSize is weird Definition at line 138 of file ltkcpp_connection.cpp.

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Member Function Documentation

int LLRP::CConnection::closeConnectionToReader (  void   )

Close connection to reader, allow reuse of instance. Returns: ==0 Connected OK, ready for business !=0 Error, check getConnectError() for reason Definition at line 405 of file ltkcpp_connection.cpp. Referenced by ~CConnection().

const char * LLRP::CConnection::getConnectError (  void   )

Get the string that explains openReaderConnection() error. Returns: ==NULL No error !=NULL Short string description of error Definition at line 388 of file ltkcpp_connection.cpp.

const CErrorDetails * LLRP::CConnection::getRecvError (  void   )

Get the details that explains recvMessage() or recvResponse() error. Returns: Pointer to const error details Definition at line 718 of file ltkcpp_connection.cpp. Referenced by getTransactError().

const CErrorDetails * LLRP::CConnection::getSendError (  void   )

Get the details that explains sendMessage() error. Returns: Pointer to const error details Definition at line 633 of file ltkcpp_connection.cpp. Referenced by getTransactError().

const CErrorDetails * LLRP::CConnection::getTransactError (  void   )

Get the details that explains transact() error. This is not 100% reliable. It looks at the send error and if that seems OK it uses the recv error. Uses of sendMessage(), recvMessage() or recvResponse() since transact() will distort the error. Returns: Pointer to const error details Definition at line 514 of file ltkcpp_connection.cpp. References getRecvError(), getSendError(), LLRP::CErrorDetails::m_eResultCode, and LLRP::RC_OK.

int LLRP::CConnection::openConnectionToReader (  const char *  pReaderHostName  )

Open the connection to the reader. The steps: Look up the host name Create a socket Connect to the host address Condition the socket (set options) Parameters: [in]  pReaderHostName  String containing the reader host name Returns: ==0 Connected OK, ready for business !=0 Error, check getConnectError() for reason Definition at line 261 of file ltkcpp_connection.cpp.

CMessage * LLRP::CConnection::recvMessage (  int  nMaxMS  )

Receive a message from a connection. The message could have already arrived and be pending on the input queue. Parameters: [in]  nMaxMS  -1 => block indefinitely 0 => just peek at input queue and socket queue, return immediately no matter what >0 => ms to await complete frame Returns: ==NULL No message available per parameters. Check getRecvError() for why !=NULL Input message Definition at line 660 of file ltkcpp_connection.cpp. References LLRP::EResultCode, LLRP::RC_MiscError, and LLRP::CErrorDetails::resultCodeAndWhatStr().

CMessage * LLRP::CConnection::recvResponse (  int  nMaxMS, const CTypeDescriptor *  pResponseType, llrp_u32_t  ResponseMessageID )

Receive a specific message from a connection. The message is identified by type and message ID. This is used to receive a response to a request, but could be used for other things, too. A message matches and is returned if the type matches AND if the message ID matches. Either or both can be wildcards. The sought message could have already arrived and be pending on the input queue. While we are looking for the response notifications might arrive. They are held in the input queue while we continue to look for the sought message. About timeLimit.... The timeLimit is the last time() we'll try to receive the sought message and prevents "spinning". It is conceivable that a steady stream of messages other than the one sought could arrive, and the time between those messages could be smaller the nMaxMS. When that happens, recvAdvance() would not time out during its poll/select. It could "spin". The time out must be detected by other means and that's the purpose of timeLimit. Parameters: [in]  nMaxMS  -1 => block indefinitely 0 => just peek at input queue and socket queue, return immediately no matter what >0 => ms to await complete frame [in]  pResponseType  The type descriptor of the sought or NULL to match all messages. If not NULL, ERROR_MESSAGE will also match. [in]  ResponseMessageID  The MessageID of sought message or 0 to match all messages. Returns: ==NULL No message available per parameters. Check getRecvError() for why !=NULL Input message Definition at line 771 of file ltkcpp_connection.cpp. References LLRP::EResultCode, LLRP::CMessage::getMessageID(), LLRP::CTypeRegistry::lookupMessage(), LLRP::CElement::m_pType, LLRP::RC_MiscError, and LLRP::CErrorDetails::resultCodeAndWhatStr(). Referenced by transact().

EResultCode LLRP::CConnection::sendMessage (  CMessage *  pMessage  )

Send a LLRP message to a connection. Parameters: [in]  pMessage  Pointer to the LLRP message to send. Returns: RC_OK Frame sent RC_SendIOError I/O error in write(). Probably means fd is bad. RC_... Encoder error. Check getSendError() for why. Definition at line 544 of file ltkcpp_connection.cpp. References LLRP::CErrorDetails::clear(), LLRP::CErrorDetails::m_eResultCode, LLRP::RC_MiscError, LLRP::RC_OK, LLRP::RC_SendIOError, and LLRP::CErrorDetails::resultCodeAndWhatStr(). Referenced by transact().

CMessage * LLRP::CConnection::transact (  CMessage *  pSendMessage, int  nMaxMS )

Transact a LLRP request and response to a connection. This is a combination of sendMessage() and recvResponse(). The MessageID is taken from the outgoing messages. It's best to not use MessageID 0. Parameters: [in]  pSendMessage  Pointer to the LLRP message to send. [in]  nMaxMS  -1 => block indefinitely 0 => just peek at input queue and socket queue, return immediately no matter what >0 => ms to await complete frame Returns: ==NULL Something failed. Use getTransactError() for best guess at what went wrong. !=NULL Response message Definition at line 451 of file ltkcpp_connection.cpp. References LLRP::CErrorDetails::clear(), LLRP::EResultCode, LLRP::CMessage::getMessageID(), LLRP::CTypeDescriptor::m_pResponseType, LLRP::CElement::m_pType, LLRP::RC_MissingResponseType, LLRP::RC_OK, recvResponse(), LLRP::CErrorDetails::resultCodeAndWhatStr(), and sendMessage().

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The documentation for this class was generated from the following files:

• ltkcpp_connection.h
• ltkcpp_connection.cpp

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