A little further explanation of the action design of the Glock pistol, if you gentlemen don't mind.
The Glock DAO is a hybrid of a sort because it does not allow for second strike capability as Dreamer pointed out. However, this has nothing to do with two distinct tasks of the trigger. As mentioned by eye95, the trigger performs two distinct tasks (actually three if we were to include the fact that it relieves the striker safety block, but that is normally not a consideration when describing trigger action). The trigger completes the cocking of the striker (action #1), then releases the striker via the cruciform to fire a cartridge (action #2).
As for second strike capability, the Glock does not have this feature unless the slide is operated manually to reset the trigger. However, neither does a double action only revolver (hammerles) have a second striker capability. What such a revolver does have is a NEW strike capability because if you pull the trigger again to fire the gun, the cylinder revolves so you will not be attempting to fire a round which failed to fire on the first try - at least until the cylinder has completed a full revolution.
Finally, I called Glock in Georgia about ten minutes ago and spoke to a tech. I asked him what term Glock uses to describe the action of their pistols. He told me that both Glock and the ATF class the Glock trigger as a Double Action Only (DAO) design.
So there you have it, gentlemen. Hope this helps and clears things up a might.