StateManager Class Template

Manages state transitions using a rule-based system. More...

Declaration

template <typename StateType> class helios::engine::state::StateManager<StateType> { ... }

Public Member Typedefs Index

template <typename StateType>
using	EngineRoleTag = helios::engine::runtime::world::tags::ManagerRole

Public Constructors Index

template <typename StateType>
StateManager (std::span< const StateTransitionRule< StateType > > rules)
	Constructs a state manager with transition rules. More...

Public Member Functions Index

template <typename StateType>
StateManager &	addStateListener (std::unique_ptr< StateTransitionListener< StateType > > listener) noexcept
	Registers a state transition listener. More...
template <typename StateType>
void	flush (helios::engine::runtime::world::UpdateContext &updateContext) noexcept
	Processes pending state commands. More...
template <typename StateType>
bool	submit (const StateCommand< StateType > stateCommand) noexcept
	Submits a state command for processing. More...
template <typename StateType>
bool	submit (const DelayedStateCommand< StateType > stateCommand) noexcept
	Submits a delayed state command for processing. More...
template <typename StateType>
void	init (helios::engine::runtime::messaging::command::CommandHandlerRegistry &commandHandlerRegistry)
	Initializes the manager and registers command handlers. More...
template <typename StateType>
void	reset ()
	Clears all pending commands. More...

Private Member Functions Index

template <typename StateType>
void	signalExit (const StateType from, const StateType to, const StateTransitionIdType< StateType > transitionId, helios::engine::runtime::world::UpdateContext &updateContext)
	Notifies listeners of state exit. More...
template <typename StateType>
void	signalTransition (const StateType from, const StateType to, const StateTransitionIdType< StateType > transitionId, helios::engine::runtime::world::UpdateContext &updateContext)
	Notifies listeners of the transition. More...
template <typename StateType>
void	signalEnter (const StateType from, const StateType to, const StateTransitionIdType< StateType > transitionId, helios::engine::runtime::world::UpdateContext &updateContext)
	Notifies listeners of state entry. More...

Private Member Attributes Index

template <typename StateType>
std::vector< StateCommand< StateType > >	pending_
	Queue of pending state commands. More...
template <typename StateType>
std::vector< std::unique_ptr< StateTransitionListener< StateType > > >	listeners_
	Registered transition listeners. More...
template <typename StateType>
std::vector< StateTransitionRule< StateType > >	rules_
	Transition rules defining valid state changes. More...

Description

Manages state transitions using a rule-based system.

Implements both Manager and TypedStateCommandHandler interfaces. Processes state transition commands by matching against registered rules, executing guards, and notifying listeners.

Definition at line 70 of file StateManager.ixx.

Public Member Typedefs

EngineRoleTag

template <typename StateType>

using helios::engine::state::StateManager< StateType >::EngineRoleTag = helios::engine::runtime::world::tags::ManagerRole

Definition at line 150 of file StateManager.ixx.

150 using EngineRoleTag = helios::engine::runtime::world::tags::ManagerRole;

Public Constructors

StateManager()

template <typename StateType>

helios::engine::state::StateManager< StateType >::StateManager (std::span< const StateTransitionRule< StateType > > rules)

inline explicit

Constructs a state manager with transition rules.

Parameters

rules

Span of valid transition rules.

Definition at line 157 of file StateManager.ixx.

157 explicit StateManager(std::span<const StateTransitionRule<StateType>> rules)

158 : rules_(rules.begin(), rules.end()) {}

Public Member Functions

addStateListener()

template <typename StateType>

StateManager & helios::engine::state::StateManager< StateType >::addStateListener (std::unique_ptr< StateTransitionListener< StateType > > listener)

inline noexcept

Registers a state transition listener.

Parameters

listener

The listener to add.

Returns

Reference to this manager for chaining.

Definition at line 167 of file StateManager.ixx.

167 StateManager& addStateListener(std::unique_ptr<StateTransitionListener<StateType>> listener) noexcept {

168 listeners_.push_back(std::move(listener));

169 return *this;

170 }

Reference helios::registerComponents.

flush()

template <typename StateType>

void helios::engine::state::StateManager< StateType >::flush (helios::engine::runtime::world::UpdateContext & updateContext)

inline noexcept

Processes pending state commands.

Processes the last pending command, finds matching rules, executes guards, and triggers the transition if valid.

Parameters

updateContext

The current frame's update context.

Definition at line 180 of file StateManager.ixx.

180 void flush(

181 helios::engine::runtime::world::UpdateContext& updateContext

182 ) noexcept {

183

184 if (pending_.empty()) {

185 return;

186 }

187

188 auto command = pending_.back();

189

190 auto transitionRequest = command.transitionRequest();

191

192 auto& session = updateContext.session();

193 auto currentFrom = session.state<StateType>();

194 auto from = transitionRequest.from();

195 auto transitionId = transitionRequest.transitionId();

196

197

198 if (currentFrom != from) {

199 pending_.clear();

200 return;

201 }

202

203

204 for (auto& rule : rules_) {

205 if (rule.from() == from && rule.transitionId() == transitionId) {

206

207 if (rule.guard()) {

208 if (!rule.guard()(updateContext, transitionRequest)) {

209 break;

210 }

211 }

212

213 signalExit(from, rule.to(), transitionId, updateContext);

214 signalTransition(from, rule.to(), transitionId, updateContext);

215 session.setStateFrom<StateType>(StateTransitionContext<StateType>{rule.from(), rule.to(), transitionId});

216 signalEnter(from, rule.to(), transitionId, updateContext);

217 }

218 }

219

220 pending_.clear();

221 }

References helios::engine::state::types::StateTransitionContext< StateType >::from and helios::registerComponents.

init()

template <typename StateType>

void helios::engine::state::StateManager< StateType >::init (helios::engine::runtime::messaging::command::CommandHandlerRegistry & commandHandlerRegistry)

inline

Initializes the manager and registers command handlers.

Parameters

commandHandlerRegistry

The command-handler registry to register with.

Definition at line 262 of file StateManager.ixx.

262 void init(helios::engine::runtime::messaging::command::CommandHandlerRegistry& commandHandlerRegistry) {

263 commandHandlerRegistry.registerHandler<StateCommand<StateType>>(*this);

264 commandHandlerRegistry.registerHandler<DelayedStateCommand<StateType>>(*this);

265 }

Reference helios::engine::runtime::messaging::command::CommandHandlerRegistry::registerHandler.

reset()

template <typename StateType>

void helios::engine::state::StateManager< StateType >::reset ()

inline

Clears all pending commands.

Definition at line 270 of file StateManager.ixx.

270 void reset() {

271 // intentionally left empty. Clearing the pending queue would also mean

272 // that any pending state transisions **required by the reset** are nuked.

273 }

submit()

template <typename StateType>

bool helios::engine::state::StateManager< StateType >::submit (const StateCommand< StateType > stateCommand)

inline noexcept

Submits a state command for processing.

Parameters

stateCommand

The command to queue.

Returns

True (always accepts commands).

Definition at line 230 of file StateManager.ixx.

230 bool submit(

231 const StateCommand<StateType> stateCommand

232 ) noexcept {

233 pending_.push_back(stateCommand);

234 return true;

235 };

Reference helios::registerComponents.

submit()

template <typename StateType>

bool helios::engine::state::StateManager< StateType >::submit (const DelayedStateCommand< StateType > stateCommand)

inline noexcept

Submits a delayed state command for processing.

Extracts the transition request from the delayed command and queues it as a regular StateCommand. The timer ID is not retained by the manager. The delayed command is guaranteed to be ready for processing when submitted here.

Parameters

stateCommand

The delayed command to queue.

Returns

True (always accepts commands).

Definition at line 250 of file StateManager.ixx.

250 bool submit(

251 const DelayedStateCommand<StateType> stateCommand

252 ) noexcept {

253 pending_.push_back(StateCommand<StateType>(stateCommand.transitionRequest()));

254 return true;

255 };

Reference helios::registerComponents.

Private Member Functions

signalEnter()

template <typename StateType>

void helios::engine::state::StateManager< StateType >::signalEnter (const StateType from, const StateType to, const StateTransitionIdType< StateType > transitionId, helios::engine::runtime::world::UpdateContext & updateContext)

inline

Notifies listeners of state entry.

Parameters

from	The source state.
to	The state being entered.
transitionId	The transition identifier.
updateContext	The current frame's update context.

Definition at line 136 of file StateManager.ixx.

136 void signalEnter(

137 const StateType from,

138 const StateType to,

139 const StateTransitionIdType<StateType> transitionId,

140 helios::engine::runtime::world::UpdateContext& updateContext) {

141

142 for (auto& listener : listeners_) {

143 listener->onStateEnter(updateContext, to);

144

145 }

146 }

signalExit()

template <typename StateType>

void helios::engine::state::StateManager< StateType >::signalExit (const StateType from, const StateType to, const StateTransitionIdType< StateType > transitionId, helios::engine::runtime::world::UpdateContext & updateContext)

inline

Notifies listeners of state exit.

Parameters

from	The state being exited.
to	The target state.
transitionId	The transition identifier.
updateContext	The current frame's update context.

Definition at line 95 of file StateManager.ixx.

95 void signalExit(

96 const StateType from,

97 const StateType to,

98 const StateTransitionIdType<StateType> transitionId,

99 helios::engine::runtime::world::UpdateContext& updateContext) {

100

101 for (auto& listener : listeners_) {

102 listener->onStateExit(updateContext, from);

103 }

104 }

signalTransition()

template <typename StateType>

void helios::engine::state::StateManager< StateType >::signalTransition (const StateType from, const StateType to, const StateTransitionIdType< StateType > transitionId, helios::engine::runtime::world::UpdateContext & updateContext)

inline

Notifies listeners of the transition.

Parameters

from	The source state.
to	The target state.
transitionId	The transition identifier.
updateContext	The current frame's update context.

Definition at line 114 of file StateManager.ixx.

114 void signalTransition(

115 const StateType from,

116 const StateType to,

117 const StateTransitionIdType<StateType> transitionId,

118 helios::engine::runtime::world::UpdateContext& updateContext) {

119

120 for (auto& listener : listeners_) {

121 listener->onStateTransition(

122 updateContext,

123 StateTransitionContext<StateType>{from, to, transitionId}

124 );

125 }

126 }

Private Member Attributes

listeners_

template <typename StateType>

std::vector<std::unique_ptr<StateTransitionListener<StateType> > > helios::engine::state::StateManager< StateType >::listeners_

Registered transition listeners.

Definition at line 80 of file StateManager.ixx.

80 std::vector<std::unique_ptr<StateTransitionListener<StateType>>> listeners_;

pending_

template <typename StateType>

std::vector<StateCommand<StateType> > helios::engine::state::StateManager< StateType >::pending_

Queue of pending state commands.

Definition at line 75 of file StateManager.ixx.

75 std::vector<StateCommand<StateType>> pending_;

rules_

template <typename StateType>

std::vector<StateTransitionRule<StateType> > helios::engine::state::StateManager< StateType >::rules_

Transition rules defining valid state changes.

Definition at line 85 of file StateManager.ixx.

85 std::vector<StateTransitionRule<StateType>> rules_;

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

• StateManager.ixx

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