Device Class Reference

Encapsulates a device (i.e., a driver bound to an interface) More...

#include <device.h>

List of all members.

Public Member Functions
	Device (player_devaddr_t addr, Driver *driver)
	Constructor.
	~Device ()
	Destructor.
int	Subscribe (QueuePointer &sub_queue)
	Subscribe the given queue to this device.
int	Unsubscribe (QueuePointer &sub_queue)
	Unsubscribe the given queue from this device.
void	PutMsg (QueuePointer &resp_queue, uint8_t type, uint8_t subtype, void *src, size_t deprecated, double *timestamp)
	Send a message to this device.
void	PutMsg (QueuePointer &resp_queue, player_msghdr_t *hdr, void *src, bool copy=true)
	Send a message to this device (short form)
Message *	Request (QueuePointer &resp_queue, uint8_t type, uint8_t subtype, void *src, size_t deprecated, double *timestamp, bool threaded=true)
	Make a request of another device.
Message *	TimedRequest (QueuePointer &resp_queue, uint8_t type, uint8_t subtype, void *src, double timeout=0, double *timestamp=NULL, bool threaded=true)
	Make a request of another device with a timeout.
Static Public Member Functions
static bool	MatchDeviceAddress (player_devaddr_t addr1, player_devaddr_t addr2)
	Compare two addresses.
Public Attributes
Device *	next
	Next entry in the device table (this is a linked-list)
player_devaddr_t	addr
	Address for this device.
char	drivername [PLAYER_MAX_DRIVER_STRING_LEN]
	The string name for the underlying driver.
QueuePointer	InQueue
	Pointer to the underlying driver's queue.
QueuePointer *	queues
	Linked list of subscribed queues.
size_t	len_queues
	Length of queues.
Driver *	driver
	Pointer to the underlying driver.
Private Member Functions
void	Lock (void)
	Lock access to driver internals.
void	Unlock (void)
	Unlock access to driver internals.
Private Attributes
pthread_mutex_t	accessMutex
	Mutex used to lock access, via Lock() and Unlock(), to device internals, like the list of subscribed queues.

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Detailed Description

Encapsulates a device (i.e., a driver bound to an interface)

A device describes an instantiated driver/interface combination. Drivers may support more than one interface, and hence appear more than once in the device table.

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Constructor & Destructor Documentation

Device::Device	(	player_devaddr_t	addr,
		Driver *	driver
	)

Constructor.

Parameters:

addr	: Device address
driver	: Pointer to the underlying driver

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Member Function Documentation

void Device::Lock

(

void

)

[private]

Lock access to driver internals.

static bool Device::MatchDeviceAddress	(	player_devaddr_t	addr1,
		player_devaddr_t	addr2
	)		[inline, static]

Compare two addresses.

This static method returns true if all 4 components of the two addresses match exactly. It's useful in Driver::ProcessMessage when you're deciding how to handle a message.

References player_devaddr::host, player_devaddr::index, player_devaddr::interf, and player_devaddr::robot.

Referenced by ImageBase::MainSetup(), LaserTransform::Setup(), wbr914::Subscribe(), P2OS::Subscribe(), Erratic::Subscribe(), wbr914::Unsubscribe(), P2OS::Unsubscribe(), and Erratic::Unsubscribe().

void Device::PutMsg	(	QueuePointer &	resp_queue,
		player_msghdr_t *	hdr,
		void *	src,
		bool	copy = true
	)

Send a message to this device (short form)

This form of PutMsg is useful if you already have the message header assembled (e.g., when you're forwarding a message).

Parameters:

resp_queue	Where to push any reply
hdr	The message header.
src	The message body (its size is stored in hdr->size).
copy	If copy is false then the message will be claimed by the device

void Device::PutMsg	(	QueuePointer &	resp_queue,
		uint8_t	type,
		uint8_t	subtype,
		void *	src,
		size_t	deprecated,
		double *	timestamp
	)

Send a message to this device.

This method is the basic way of sending a message to a device. The header will be assembled and the message will get pushed on to the underlying driver's InQueue.

Parameters:

resp_queue	: Where to push any reply (e.g., your InQueue)
type	: Message type
subtype	: Message subtype
src	: Message payload
deprecated,:	Used to be the length of the message this is now calculated
timestamp	: If non-NULL, the timestamp to attach to the message; otherwise, the current time is filled in.

Referenced by SegwayRMP400::HandlePosition2DCmd(), SegwayRMP400::HandlePosition3DCmd(), ToRanger::ProcessMessage(), LaserTransform::ProcessMessage(), and FromRanger::ProcessMessage().

Message* Device::Request	(	QueuePointer &	resp_queue,
		uint8_t	type,
		uint8_t	subtype,
		void *	src,
		size_t	deprecated,
		double *	timestamp,
		bool	threaded = true
	)

Make a request of another device.

This method send a request message to a device and waits for the reply.

Parameters:

resp_queue	: Where to push the reply (e.g., your InQueue)
type	: Message type (usually PLAYER_MSGTYPE_REQ).
subtype	: Message subtype (interface-specific)
src	: Message body
deprecated,:	Used to be the length of the message this is now calculated
timestamp	: If non-NULL, the timestamp to attach to the request; otherwise, the current time is filled in.
threaded	: True if the caller is executing in its own thread, false otherwise

Note:

It is is crucial that threaded be set correctly. If you call this method from within Setup() or Shutdown(), or if your driver does not run in its own thread, then threaded must be false. Deadlocks will otherwise result.

Returns:

A pointer to the reply message. The caller is responsible for deleting this pointer.

Referenced by snd::ProcessMessage(), and SegwayRMP400::ProcessMessage().

int Device::Subscribe

(

QueuePointer &

sub_queue

)

Subscribe the given queue to this device.

Returns:

0 on success, non-zero otherwise.

Referenced by LaserTransform::Setup().

Message* Device::TimedRequest	(	QueuePointer &	resp_queue,
		uint8_t	type,
		uint8_t	subtype,
		void *	src,
		double	timeout = 0,
		double *	timestamp = NULL,
		bool	threaded = true
	)

Make a request of another device with a timeout.

This method send a request message to a device and waits for the reply. If a timeout occurs it returns NULL.

Note that any driver calling this here a timeout is not going to be a bad error also needs to add into its process messages somethig to handle the ACKs if they are recieved after the timeout. As such I would recomment that this is only called with a timeout not 0 if a timeout occurring is an indicaion of a system ailure (and a stall is unacceptable)

Parameters:

resp_queue	: Where to push the reply (e.g., your InQueue)
type	: Message type (usually PLAYER_MSGTYPE_REQ).
subtype	: Message subtype (interface-specific)
src	: Message body
timeout,:	How long to wait for a response, if zero will never timeout
timestamp	: If non-NULL, the timestamp to attach to the request; otherwise, the current time is filled in.
threaded	: True if the caller is executing in its own thread, false otherwise

Note:

It is is crucial that threaded be set correctly. If you call this method from within Setup() or Shutdown(), or if your driver does not run in its own thread, then threaded must be false. Deadlocks will otherwise result.

Returns:

A pointer to the reply message. The caller is responsible for deleting this pointer. Will return NULL on a failure

void Device::Unlock

(

void

)

[private]

Unlock access to driver internals.

int Device::Unsubscribe

(

QueuePointer &

sub_queue

)

Unsubscribe the given queue from this device.

Returns:

0 on success, non-zero otherwise.

Referenced by snd::Shutdown(), and LaserTransform::Shutdown().

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Member Data Documentation

pthread_mutex_t Device::accessMutex [private]

Mutex used to lock access, via Lock() and Unlock(), to device internals, like the list of subscribed queues.

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

• device.h