///<summary>Combines two souls by using a custom function to combine their phases.</summary>
public static ISoul Combine(this ISoul soul1, ISoul soul2, Func <Phase, Phase, Phase> phaseCombiner)
{
Func <Phase> getPhase = () => phaseCombiner(soul1.Phase, soul2.Phase);
return(new AnonymousSoul(
getPhase,
action => {
Func <bool> tryComplete = () => {
var hasPhase = getPhase() != Phase.Mortal;
if (hasPhase)
{
action();
}
return hasPhase;
};
return soul1.InterdependentRegister(tryComplete, soul2, tryComplete);
}));
}
///<summary>Registers a callback to the dependent soul that only occurs if the necessary soul doesn't die first, ensuring everything is cleaned up properly.</summary>
public static RegistrationRemover DependentRegister(this ISoul soul, Action action, ISoul necessarySoul)
{
if (soul == null)
{
throw new ArgumentNullException("soul");
}
if (action == null)
{
throw new ArgumentNullException("action");
}
if (necessarySoul == null)
{
throw new ArgumentNullException("necessarySoul");
}
// when the necessary soul is the same soul as the dependent soul, assume the callback invocation will beat the registration removal
if (ReferenceEquals(soul, necessarySoul))
{
necessarySoul = ImmortalSoul.Instance;
}
// avoid wrapping when possible
if (necessarySoul.Phase == Phase.Dead)
{
return(EmptyRemover);
}
if (soul.Phase != Phase.Mortal)
{
action();
return(EmptyRemover);
}
if (necessarySoul.Phase == Phase.Immortal)
{
return(soul.Register(action));
}
return(soul.InterdependentRegister(
() => {
action();
return true;
},
necessarySoul,
() => necessarySoul.Phase == Phase.Dead));
}