Chapter 1

else
// Everything was OK, leave this state
nextState = iState->CompleteL();
}
{
// Something went wrong, ERROR
nextState = iState->ErrorL(err);
}
// Just move on to the next state (could be NULL, in which case
we're done)
ChangeState(nextState);
}
Here, I selectively call either the CompleteL() or ErrorL() members of the current state,
depending on the outcome of the asynchronous request as returned by iStatus.Int(),
inherited from CActive.
Both these member functions indicate state entry asynchronous request completion. I've just
separated them for implementation convenience within the concrete state classes.
Either one of the state completion functions may return a new state to try to enter next. If
NULL is returned, we drop out of RunL() and revert to inactive mode.
Note that unlike ChangeState() this is not run within a trap harness. CActive provides
RunError() to handle and leaves occurring within RunL().
TInt CGdpStateMachine::RunError(TInt aError)
/**
**/
This is called if RunL leaves.
This will be through CompleteL or ErrorL leaving.
Handle the error in the state machine.
{
TState* nextState = ErrorOnStateExit(aError);
ChangeState(nextState);
return KErrNone;
}
Any errors are passed to the concrete state machine's ErrorOnStateExit() error
handler.
Note that SetActive() is never called by the state machine. This is entirely the
responsibility of the concrete state classes, whenever they make an asynchronous request.
The remaining state machine functions are fairly straightforward. The most interesting are
DoCancel(), which simply calls the Cancel() member of the current state, and