What does he mean by that in plain English? Why doesn’t the barman understand?

In Chapter VIII Winston visits a district that is inhabited by proles. The proles are generally friendly, but speak informally and use a lot of slang. Winston visits a pub because he wants to ask an old man about the past, especially about what the party says about capitalists. When Winston first sees him, he is arguing with the barman. Winston says “I arst you civil enough, didn’t I? You telling me you ain’t got a pint mug in the ‘ole bleeding boozer?”