Subsys Class Reference

#include "common/subsys.hpp"

Description

Dependencies and lifecycle of a partially independent Subsystem of the Application.

Using such descriptors, AppState as activated from main() is able to pull up, maintain and shut down the primary parts of the Application.

Note

synchronisation is up to the implementor.

Definition at line 61 of file subsys.hpp.

Public Types
typedef function< void(string *)>	SigTerm

Public Member Functions
virtual	~Subsys ()
virtual	operator string () const =0
	a human readable name
Subsys &	depends (Subsys &prereq)
	define a dependency to another Subsys required for running this subsystem
bool	isRunning () noexcept
virtual bool	shouldStart (lumiera::Option &)=0
	query application option state to determine if this subsystem should be activated.
virtual bool	start (lumiera::Option &options, SigTerm)=0
	attempt to bring up this subsystem up.
virtual void	triggerShutdown () noexcept=0
	initiate termination of this subsystem.
const std::vector< Subsys * >	getPrerequisites ()

Private Member Functions
virtual bool	checkRunningState () noexcept=0
	whether this subsystem is actually operational.
Private Member Functions inherited from NonCopyable
	~NonCopyable ()=default
	NonCopyable ()=default
	NonCopyable (NonCopyable const &)=delete
NonCopyable &	operator= (NonCopyable const &)=delete

Private Attributes
std::vector< Subsys * >	prereq_

Constructor & Destructor Documentation

~Subsys()

~Subsys ( )

virtual

Definition at line 36 of file subsys.cpp.

Member Typedef Documentation

SigTerm

typedef function<void(string*)> SigTerm

Definition at line 65 of file subsys.hpp.

Member Function Documentation

operator string()

virtual operator string ( ) const

pure virtual

a human readable name

Implemented in GuiSubsysDescriptor, SessionSubsystem, PlayOutSubsysDescriptor, EngineSubsysDescriptor, NetNodeSubsysDescriptor, ScriptRunnerSubsysDescriptor, and MockSys.

depends()

Subsys & depends

(

Subsys &

prereq

)

define a dependency to another Subsys required for running this subsystem

Definition at line 41 of file subsys.cpp.

References Subsys::prereq_.

Referenced by main().

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isRunning()

bool isRunning ( )

noexcept

Returns

true if Up

Warning

must not block nor throw.

Definition at line 50 of file subsys.cpp.

References Subsys::checkRunningState().

Referenced by SubsystemRunner::maybeRun(), SubsystemRunner::sigTerm(), and SubsystemRunner::triggerStartup().

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shouldStart()

virtual bool shouldStart ( lumiera::Option &  )

pure virtual

query application option state to determine if this subsystem should be activated.

Note

even if not started explicitly, it could still be started as prerequisite of another one

Implemented in EngineSubsysDescriptor, NetNodeSubsysDescriptor, ScriptRunnerSubsysDescriptor, MockSys, GuiSubsysDescriptor, SessionSubsystem, and PlayOutSubsysDescriptor.

Referenced by SubsystemRunner::maybeRun().

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start()

virtual bool start ( lumiera::Option &  options, SigTerm    )

pure virtual

attempt to bring up this subsystem up.

On return, the subsystem must be operational, according to checkRunningState(). Failure to start up usually terminates the whole application. When this subsystem ceases to work, it must ensure to activate the given callback signal.

Parameters

options	may be influencing the operation mode
SigTerm	to be signalled by the subsystem.

Warning

termination must be signalled reliably.

Returns

true if actually started.

Implemented in NetNodeSubsysDescriptor, ScriptRunnerSubsysDescriptor, EngineSubsysDescriptor, MockSys, GuiSubsysDescriptor, PlayOutSubsysDescriptor, and SessionSubsystem.

Referenced by SubsystemRunner::triggerStartup().

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triggerShutdown()

virtual void triggerShutdown ( )

pure virtualnoexcept

initiate termination of this subsystem.

This trigger may be called repeatedly any time... When the subsystem actually has terminated, the SigTerm passed to start must be invoked.

Note

called within a locked context (barrier)

Warning

must not block nor throw.

Implemented in GuiSubsysDescriptor, SessionSubsystem, PlayOutSubsysDescriptor, EngineSubsysDescriptor, NetNodeSubsysDescriptor, ScriptRunnerSubsysDescriptor, and MockSys.

Referenced by SubsystemRunner::shutdownAll(), and SubsystemRunner::triggerStartup().

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getPrerequisites()

const std::vector< Subsys * > getPrerequisites ( )

inline

Definition at line 111 of file subsys.hpp.

References Subsys::prereq_.

Referenced by SubsystemRunner::triggerStartup().

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checkRunningState()

virtual bool checkRunningState ( )

privatepure virtualnoexcept

whether this subsystem is actually operational.

When returning false here, the application may terminate at any point without further notice Note further, that a subsystem must not be in running state when signalling termination.

Implemented in GuiSubsysDescriptor, SessionSubsystem, PlayOutSubsysDescriptor, EngineSubsysDescriptor, NetNodeSubsysDescriptor, ScriptRunnerSubsysDescriptor, and MockSys.

Referenced by Subsys::isRunning().

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Member Data Documentation

prereq_

std::vector<Subsys*> prereq_

private

Definition at line 122 of file subsys.hpp.

Referenced by Subsys::depends(), and Subsys::getPrerequisites().

Inheritance diagram for Subsys:

Collaboration diagram for Subsys:

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

• subsys.hpp
• subsys.cpp