Damage and Greater Stunning Barrier

[Garrick75]

SB and GSB both provide an AC bonus. Both activate when the caster is hit by a foe's attack(s).

My question is: If an opponent beats my AC while SB/GSB is active, and they fail the save and are stunned, do they still deal damage to me?

Which resolves first? The damage? Or does the magic stun and stop them before they deal damage? Technically all 3 rolls are done at the same time between actions.

[dragonhunterq]

It doesn't stun until after you are struck, you will take damage first.

SB wrote:

Any creature that strikes you with a melee attack...

[Saethori]

Stunning Barrier triggers when you are struck. This means when an attack passes your AC and any checks such as concealment or Mirror Image. It does not need to have penetrated any DR you might possess.

When you are struck, then they are stunned. One, then the next. If it somehow stopped the attack from hitting you, then you are not being struck, which means it's not triggering... this obviously is a loop, so it seems clear from a logical perspective that unless it says otherwise, it's one, then the next.