What could my postdoctoral advisor do, now that he knows that I started looking for positions in industry? I'm a non-EU postdoctoral researcher in Europe who recently started looking for company jobs. I just informed my advisor that. He asked me where, and I said the name of the same city we are in, because that's my most preferred choice. Now, my postdoc is till the end of the year (if not renewed), and I know that I've the right to leave at any time I like with probably a one month's notice. 

I initially intended to tell him only after getting an offer, but I felt he should know it in any case, because if I leave abruptly in a month, that'd be a sudden blow on him.

He didn't say much, except asking when I'm looking to join. I said I didn't get any offer yet, and plan to finish what I started, if the company allows that. My only fear is: can my postdoctoral advisor try to sack me because of this? Did I just make a mistake? Our relation is okay (not superb), and I report regularly to him.

What would you do if you were a postdoctoral advisor in this situation? Thanks a lot!

EDIT: Okay he had a small chat with me just now. He told me that if I find a job soon, he's okay if I start immediately, he'd not have anything against it. The reason being that he thinks the project might take longer than a year, and he himself isn't sure about the funding status for the next year yet.

So it seems not to be a bad sign yet.
My feeling is that most supervisors/PIs are aware of the realities of being a postdoc, having been one themselves at one point. I suspect that he valued your honesty, and understands that most people would like a well paid job with stability.

Unless he's shown some signs of being an awful person, I would assume he was asking you out of personal interest, and so that he organise his grants and find a replacement if possible.