template <typename StateMachine, typename State, typename Input>

class StateMachineBase

Defined at line 29 of file ../../src/devices/power/drivers/fusb302/state-machine-base.h

Scaffolding for implementing a state machine in the USB PD spec.

`StateMachine` is the class deriving from this base class.

`State` is the type representing a state. It should be a value type,

equivalent to a scoped enum whose underlying representation is a signed

integer. In particular, instances must be copyable (and the copy operation is

assumed to be cheap), must be convertible to int64_t, and the copies must be

safe to store for the state machine instance's entire lifetime.

`Input` is the type representing an `EnterState` input. It must be trivially

copyable.

Public Methods

void StateMachineBase<StateMachine, State, Input> (State initial_state, inspect::Node inspect_root, const char * debug_name)

Defined at line 31 of file ../../src/devices/power/drivers/fusb302/state-machine-base.h

void StateMachineBase<StateMachine, State, Input> (const StateMachineBase<StateMachine, State, Input> & )

Defined at line 36 of file ../../src/devices/power/drivers/fusb302/state-machine-base.h

StateMachineBase<StateMachine, State, Input> & operator= (const StateMachineBase<StateMachine, State, Input> & )

Defined at line 37 of file ../../src/devices/power/drivers/fusb302/state-machine-base.h

void ~StateMachineBase<StateMachine, State, Input> ()

Defined at line 39 of file ../../src/devices/power/drivers/fusb302/state-machine-base.h

State current_state ()

Defined at line 41 of file ../../src/devices/power/drivers/fusb302/state-machine-base.h

void Run (Input input)

Evaluates `input` against the state machine until it stops transitioning.

Defined at line 96 of file ../../src/devices/power/drivers/fusb302/state-machine-base.h

void EnterState (State state)

Called on a transition into `state`.

Implementations must not change the current state, e.g. by calling

`ForceStateTransition()`.

State NextState (Input input, State current_state)

Decides if `input` received in `current_state` warrants a state change.

Returns the state machine's new state, which can be `current_state` if no

transition is warranted.

Implementations must not change the current state, e.g. via

`ForceStateTransition()`.

Implementation advice: "return current_state;" is a readable way to express

the lack of a state transition.

void ExitState (State state)

Called on a transition out of `state`.

Implementations must not change the current state, e.g. by calling

`ForceStateTransition()`.

const char * StateToString (State state)

Returns a developer-friendly description of `state` suitable for logging.

inspect::Node & inspect_root ()

Defined at line 86 of file ../../src/devices/power/drivers/fusb302/state-machine-base.h

void ForceStateTransition (State new_state)

Subclass hook for changing the state outside of Run().

This method can be used to allow changing a state machine's state without

invoking the `Run()` / `NextState()` machinery. This can help implement

specifications that allow "out-of-band" state changes, without having to

burden `NextState()` with knowledge of these out-of-band state changes.

This method is not public so that subclasses can enforce boundaries on the

arbitrary state transitions. For example, a subclass may choose to only

allow transitioning to designated states, such as "disabled" or "ready".

Defined at line 123 of file ../../src/devices/power/drivers/fusb302/state-machine-base.h