Manager implementation that starts Workers by calling fork(2). More...

#include <be_process_forkmanager.h>

Inherits BiometricEvaluation::Process::Manager.

Public Member Functions
	ForkManager ()
	ForkManager constructor. More...

std::shared_ptr< WorkerController >	addWorker (std::shared_ptr< Worker > worker)
	Adds a Worker to be managed by this Manager. More...

void	startWorkers (bool wait=true, bool communicate=false)
	Begin Worker's work. More...

void	startWorker (std::shared_ptr< WorkerController > worker, bool wait=true, bool communicate=false)
	Start a worker. More...

void	stopWorker (std::shared_ptr< WorkerController > workerController)
	Ask Worker to exit. More...

void	broadcastSignal (int signo)
	Send a POSIX signal to all workers. More...

bool	responsibleFor (const pid_t pid) const
	Obtain whether or not this ForkManager is responsbile for a particular PID. More...

void	setNotWorking (const pid_t pid)
	Set Status.isWorking for PID to false. More...

void	markAllFinished ()
	Call setNotWorking() for all PIDs known to this ForkManager. More...

bool	getIsWorkingStatus (const pid_t pid) const
	Get Status.isWorking for PID. More...

void	waitForWorkerExit ()
	Block until all Workers have exited. More...

	~ForkManager ()
	ForkManager destructor. More...

void	setExitCallback (void(*exitCallback)(std::shared_ptr< ForkWorkerController > worker, int stat_loc))
	Call a function in your program when a child exits. More...

void	setExitStatus (const pid_t pid, const int32_t waitStatus)
	Set the exit status in the WorkerController for given process ID. More...

Public Member Functions inherited from BiometricEvaluation::Process::Manager
	Manager ()
	Manager constructor. More...

virtual std::shared_ptr< WorkerController >	addWorker (std::shared_ptr< Worker > worker)=0
	Adds a Worker to be managed by this Manager. More...

virtual uint32_t	getNumCompletedWorkers () const
	Obtain the number of Workers that have exited. More...

virtual uint32_t	getNumActiveWorkers () const
	Obtain the number of Workers that are still working. More...

virtual uint32_t	getTotalWorkers () const
	Obtain the number of Workers this class is handling. More...

virtual void	startWorkers (bool wait=true, bool communicate=false)=0
	Begin Worker's work. More...

virtual void	startWorker (std::shared_ptr< WorkerController > worker, bool wait=true, bool communicate=false)=0
	Start a Worker. More...

virtual void	waitForWorkerExit ()=0
	Block until all Workers have exited. More...

virtual void	reset ()
	Reuse all Workers. More...

virtual void	stopWorker (std::shared_ptr< WorkerController > worker)=0
	Ask Worker to return as soon as possible. More...

virtual bool	waitForMessage (std::shared_ptr< WorkerController > &sender, int *nextFD=nullptr, int numSeconds=-1) const
	Wait for a message from a Worker. More...

virtual bool	getNextMessage (std::shared_ptr< WorkerController > &sender, Memory::uint8Array &message, int numSeconds=-1) const
	Obtain a message from a Worker. More...

virtual void	broadcastMessage (Memory::uint8Array &message) const
	Send one message to all Workers. More...

virtual	~Manager ()
	Manager destructor. More...

Static Public Member Functions
static void	defaultExitCallback (std::shared_ptr< ForkWorkerController > worker, int status)
	A default exit callback function. More...

Static Public Attributes
static std::list< ForkManager * >	FORKMANAGERS
	List of all instantiated ForkManagers. More...

Additional Inherited Members
virtual void	_wait ()=0
	Do not return until all spawned processes exited. More...

Protected Attributes inherited from BiometricEvaluation::Process::Manager
std::vector< std::shared_ptr< WorkerController > >	_workers
	Workers that have been added. More...

std::vector< std::shared_ptr< WorkerController > >	_pendingExit
	Workers that are about to exit (stop requested). More...

Detailed Description

Manager implementation that starts Workers by calling fork(2).

Definition at line 32 of file be_process_forkmanager.h.

Constructor & Destructor Documentation

◆ ForkManager()

BiometricEvaluation::Process::ForkManager::ForkManager ( )

ForkManager constructor.

◆ ~ForkManager()

BiometricEvaluation::Process::ForkManager::~ForkManager ( )

ForkManager destructor.

Member Function Documentation

◆ addWorker()

std::shared_ptr< WorkerController > BiometricEvaluation::Process::ForkManager::addWorker ( std::shared_ptr< Worker > worker )

virtual

Adds a Worker to be managed by this Manager.

Parameters

worker A Worker instance to run.

Returns: shared_ptr to worker.

Implements BiometricEvaluation::Process::Manager.

◆ startWorkers()

void BiometricEvaluation::Process::ForkManager::startWorkers	(	bool	wait = `true`,
		bool	communicate = `false`
	)

virtual

Begin Worker's work.

Parameters

[in]	wait	Whether or not to wait for all Workers to return before returning.
[in]	communicate	Whether or not to enable communication among the Workers and Managers.

Exceptions

Error::ObjectExists	At least one Worker is already working.
Error::StrategyError	Problem forking.

Implements BiometricEvaluation::Process::Manager.

◆ startWorker()

void BiometricEvaluation::Process::ForkManager::startWorker	(	std::shared_ptr< WorkerController >	worker,
		bool	wait = `true`,
		bool	communicate = `false`
	)

virtual

Start a worker.

Parameters

	worker	Pointer to a WorkerController that is being managed by this Manager instance.
	wait	Whether or not to wait for this Worker to exit before returning control to the caller.
[in]	communicate	Whether or not to enable communication among the Workers and Managers.

Exceptions

Error::ObjectExists	worker is already working.
Error::StrategyError	worker is not managed by this Manager instance.

Implements BiometricEvaluation::Process::Manager.

◆ stopWorker()

void BiometricEvaluation::Process::ForkManager::stopWorker ( std::shared_ptr< WorkerController > workerController )

virtual

Ask Worker to exit.

Sends SIGUSR1 to the Worker, which ForkManager will handle automatically.

Parameters

workerController Pointer to the ForkWorkerController that should be stopped.

Exceptions

Error::ObjectDoesNotExist	worker is not working.
Error::StrategyError	Problem sending the signal.

Attention: Do not call stopWorker() when communication is enabled unless you will be finished with communication for all Workers at that point. This creates a race condition for reads()/writes() when the Worker exits.

Implements BiometricEvaluation::Process::Manager.

◆ broadcastSignal()

void BiometricEvaluation::Process::ForkManager::broadcastSignal ( int signo )

Send a POSIX signal to all workers.

Parameters

[in] signo The signal to send.

◆ responsibleFor()

bool BiometricEvaluation::Process::ForkManager::responsibleFor ( const pid_t pid ) const

Obtain whether or not this ForkManager is responsbile for a particular PID.

Parameters

[in] pid PID in question

Returns: true if this ForkManager spawned pid, false otherwise.

◆ setNotWorking()

void BiometricEvaluation::Process::ForkManager::setNotWorking ( const pid_t pid )

Set Status.isWorking for PID to false.

Parameters

[in] pid PID whose inWorking flag should be set to false

Exceptions

Error::ObjectDoesNotExist PID not under this manager's control.

◆ markAllFinished()

void BiometricEvaluation::Process::ForkManager::markAllFinished ( )

Call setNotWorking() for all PIDs known to this ForkManager.

◆ getIsWorkingStatus()

bool BiometricEvaluation::Process::ForkManager::getIsWorkingStatus ( const pid_t pid ) const

Get Status.isWorking for PID.

Parameters

[in] pid PID whose inWorking flag should be queried

Exceptions

Error::ObjectDoesNotExist PID not under this manager's control.

◆ waitForWorkerExit()

void BiometricEvaluation::Process::ForkManager::waitForWorkerExit ( )

virtual

Block until all Workers have exited.

Use this method if wait=false was set during a call to startWorker(s) but now wait=true is desired.

Implements BiometricEvaluation::Process::Manager.

◆ setExitCallback()

void BiometricEvaluation::Process::ForkManager::setExitCallback ( void(*)(std::shared_ptr< ForkWorkerController > worker, int stat_loc) exitCallback )

Call a function in your program when a child exits.

Parameters

exitCallback Function pointer to a method that takes a shared_ptr to a ForkWorkerController and the integer status information.

Note: The exit callback will not have any effect if the Manager is not set to wait for Workers.

◆ defaultExitCallback()

static void BiometricEvaluation::Process::ForkManager::defaultExitCallback	(	std::shared_ptr< ForkWorkerController >	worker,
		int	status
	)

static

A default exit callback function.

Writes to stdout in the form: PID #: Exited .

Parameters

worker	The ForkWorkerController object that exited.
status	The status of the Worker that exited (from wait(2)).

◆ setExitStatus()

void BiometricEvaluation::Process::ForkManager::setExitStatus	(	const pid_t	pid,
		const int32_t	waitStatus
	)

Set the exit status in the WorkerController for given process ID.

Parameters

[in]	pid	PID whose exit status should be set.
[in]	status	Status, as returned from wait(2).

Exceptions

Error::ObjectDoesNotExist PID not under this manager's control.

Note: Exit status is only set if process exited cleanly.

Member Data Documentation

◆ FORKMANAGERS

std::list<ForkManager*> BiometricEvaluation::Process::ForkManager::FORKMANAGERS

static

List of all instantiated ForkManagers.

This is not a list of managed pointers to ForkManagers. If it was, the smart pointer's destructor would attempt to delete the object being pointed to at program termination, which is ultimately sometime after the destructor of the ForkManager itself was called.

Definition at line 46 of file be_process_forkmanager.h.

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

be_process_forkmanager.h

Public Member Functions

Static Public Member Functions

Static Public Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ ForkManager()

◆ ~ForkManager()

Member Function Documentation

◆ addWorker()

◆ startWorkers()

◆ startWorker()

◆ stopWorker()

◆ broadcastSignal()

◆ responsibleFor()

◆ setNotWorking()

◆ markAllFinished()

◆ getIsWorkingStatus()

◆ waitForWorkerExit()

◆ setExitCallback()

◆ defaultExitCallback()

◆ setExitStatus()

Member Data Documentation

◆ FORKMANAGERS