gcp::util::SignalTask Class Reference

#include <SignalTask.h>

Inheritance diagram for gcp::util::SignalTask:

Classes
class	SignalHandler
class	TimerInfo

Public Member Functions
	SignalTask (bool spawnThread=false)
virtual	~SignalTask ()
void	sendInstallTimerMsg (std::string name, int sigNo, unsigned long initSec, unsigned long initNsec, unsigned long intervalSec, unsigned long intervaNsec, SIGNALTASK_HANDLER_FN(*handler))
void	sendAddHandlerMsg (std::string name, SIGNALTASK_HANDLER_FN(*handler), bool add)
void	sendInstallSignalMsg (int sigNo, SIGNALTASK_HANDLER_FN(*handler), void *arg=NULL)
void	sendAddHandlerMsg (int sigNo, SIGNALTASK_HANDLER_FN(*handler), bool add)
void	sendEnableTimerMsg (std::string name, bool enable)
void	stopTimers ()
int	getIoSig ()
virtual void	run ()
void	serviceMsgQ ()
Public Member Functions inherited from gcp::util::GenericTask< gcp::util::SignalTaskMsg >
void	sendRestartMsg ()
void	sendStopMsg ()
void	sendHeartBeatMsg ()

Protected Attributes
sigset_t	handledSignals_
Protected Attributes inherited from gcp::util::GenericTask< gcp::util::SignalTaskMsg >
Thread *	thread_
std::vector< Thread * >	threads_
PipeQ< gcp::util::SignalTaskMsg >	msgq_
gcp::util::FdSet	fdSet_
std::vector< Command * >	commands_
struct timeval *	timeOut_
TimeVal	commandTimeOut_

Additional Inherited Members
Protected Member Functions inherited from gcp::util::GenericTask< gcp::util::SignalTaskMsg >
	GenericTask ()
	GenericTask (Thread *thread)
virtual	~GenericTask ()
void	sendTaskMsg (gcp::util::SignalTaskMsg *msg)
void	startThreads (void *arg)
void	startThread (void *arg, unsigned order)
unsigned	getMinStartOrder ()
bool	threadsNeedStarting ()
void	cancelThreads ()
void	cancelThread (unsigned order)
unsigned	getMinCancelOrder ()
bool	threadsNeedCancelling ()
void	pingThreads (void *arg)
void	raise (std::string name, int sigNo)
Thread *	getThread (std::string name)
bool	threadsAreRunning ()
void	shutdownConnection (int fd)
virtual void	restart (void)
virtual void	processMsg (gcp::util::SignalTaskMsg *msg)
virtual void	respondToHeartBeat ()
virtual void	addHandler (gcp::util::SignalTaskMsg *msg)
void	stepCommands ()

Detailed Description

A generic base-class task for handling timers & signals.

Context:

Under pthreads, there is no guarantee which thread a signal will be delivered to, so traditional use of signal handlers in multiple threads is unsafe.

The safe way of handling signals under pthreads is to block signals in all threads but one, which is dedicated to servicing all signals.

The default run() method of this class handles signals in normal code, by blocking in a loop on sigwait() until any catchable signal has arrived. On receipt of a signal, if a handler has been installed for that signal using either installTimer() or installSignal() methods below, that handler is called. Note that all signals are blocked between calls to sigwait(), so that we are guaranteed not to be interrupted by another signal while servicing one that has just arrived.

Each pass of the loop atomically unblocks a set of signals specified by a sigset_t* argument passed to sigwait(). This set is modified by calls to installTimer() and installSignal(), below.

SignalTask installs

Constructor & Destructor Documentation

SignalTask::SignalTask

(

bool

spawnThread = false

)

Constructor for SignalTask. The thread id is set in this constructor to the id returned by pthread_self(). Calling our internal send*Msg() methods will therefore cause an I/O signal to be raised to the thread which instantiated this object, causing the message queue to be checked.

....................................................................... Constructor.

SignalTask::~SignalTask ( )

virtual

Making the destructor virtual ensures that the right destructor will be called for classes which inherit from SignalTask.

....................................................................... Destructor: Delete any timers managed by this task.

Member Function Documentation

int SignalTask::getIoSig

(

)

Query what signal this object uses for I/O events.

....................................................................... Return which signal this object uses for I/O events.

void SignalTask::run ( void  )

virtual

Run, handling signals.

....................................................................... A run method for this task.

Reimplemented from gcp::util::GenericTask< gcp::util::SignalTaskMsg >.

void gcp::util::SignalTask::sendAddHandlerMsg	(	std::string	name,
		SIGNALTASK_HANDLER_FN *	handler,
		bool	add
	)

Send a message to attach a handler to an existing timer.

void SignalTask::sendAddHandlerMsg	(	int	sigNo,
		SIGNALTASK_HANDLER_FN *	handler,
		bool	add
	)

Send a message to attach a handler to a signal.

....................................................................... Send a message to add a handler to the set attached to this timer.

void SignalTask::sendEnableTimerMsg	(	std::string	name,
		bool	enable
	)

Send a message to enable/disable a timer.

....................................................................... Respond to a message to enable/disable a timer.

void SignalTask::sendInstallSignalMsg	(	int	sigNo,
		SIGNALTASK_HANDLER_FN *	handler,
		void *	arg = NULL
	)

Send a message to install a signal.

....................................................................... Send a message to install a signal.

void SignalTask::sendInstallTimerMsg	(	std::string	name,
		int	sigNo,
		unsigned long	initSec,
		unsigned long	initNsec,
		unsigned long	intervalSec,
		unsigned long	intervaNsec,
		SIGNALTASK_HANDLER_FN *	handler
	)

Send a message to install a timer.

....................................................................... Send a message to install a timer.

void SignalTask::serviceMsgQ ( void  )

virtual

Service our message queue.

....................................................................... Check our message queue for pending messages.

Reimplemented from gcp::util::GenericTask< gcp::util::SignalTaskMsg >.

void SignalTask::stopTimers

(

)

Stop all timers.

....................................................................... Stop all timers

Member Data Documentation

sigset_t gcp::util::SignalTask::handledSignals_

protected

The set of signals handled by this task. We make this protected so that inheritors of this class can redefine run(), which may require access to handledSignals_.

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

• gcpCbass/util/common/SignalTask.h
• gcpCbass/util/common/SignalTask.cc