A glock or a revolver.
Both are similar in that there is no safety lever. When you pull the trigger, both are good to go.
Therefore, you have to realize the you are the safety and practice the NRA's three golden rules of handgun safety. Uniquely, a violaiton of the two while still practicing one should prevent a severe mistake.
But in an emergency situation, they are both so simple that you don't have to fumble for any lever, you essentially load and for the Glock, rack the slide and let it go, don't ease it back, and fire.
Both very simple to maintain as well.
1. ALWAYS keep the gun pointed in a safe direction.
This is the primary rule of gun safety. A safe direction means that the gun is pointed so that even if it were to go off it would not cause injury or damage. The key to this rule is to control where the muzzle or front end of the barrel is pointed at all times. Common sense dictates the safest direction, depending on different circumstances.
2. ALWAYS keep your finger off the trigger until ready to shoot.
When holding a gun, rest your finger on the trigger guard or along the side of the gun. Until you are actually ready to fire, do not touch the trigger.
3. ALWAYS keep the gun unloaded until ready to use.
Whenever you pick up a gun, immediately engage the safety device if possible, and, if the gun has a magazine, remove it before opening the action and looking into the chamber(s) which should be clear of ammunition. If you do not know how to open the action or inspect the chamber(s), leave the gun alone and get help from someone who does.