Device Class Reference

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

#include <device.h>

Collaboration diagram for Device:

List of all members.


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.

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)
MessageRequest (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.
MessageTimedRequest (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

Devicenext
 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.
QueuePointerqueues
 Linked list of subscribed queues.
size_t len_queues
 Length of queues.
Driverdriver
 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.

Constructor & Destructor Documentation

Device::Device ( player_devaddr_t  addr,
Driver driver 
)

Constructor.

Parameters:
addr: Device address
driver: Pointer to the underlying driver

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(), mbasedriver::Subscribe(), Erratic::Subscribe(), wbr914::Unsubscribe(), P2OS::Unsubscribe(), mbasedriver::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_queueWhere to push any reply
hdrThe message header.
srcThe message body (its size is stored in hdr->size).
copyIf 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().


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.


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