I've been playing Pathfinder for a while, but have also been playing D&D 3.X since they were published. In D&D there is the Warlock class, but in Pathfinder I have yet to find such a class other than in a third-party release (Adamant Entertainment). Is there an official Warlock class for Pathfinder?
None of the 3.5 classes or feats that were released in "splatbooks" (books besides the core three) are likely to ever appear in Pathfinder, owing to legal issues. Basically, they're considered Wizards' Product Identity, not Open Game Content, and can't be copied by Paizo, the makers of Pathfinder.
However, Pathfinder is fully 3.5 compatible. You can play the Warlock as written or modify it to be more like the updated Pathfinder classes and it should work, rules-wise. You might have some occasional issues that require some GM adjudication, but for the most part the class should work just fine. This is true for virtually every splat-class in 3.5.
As far as official Pathfinder suggestions go...
Thematically (fluff-wise), the Witch is pretty near a Warlock. Power from a (usually dark) otherworldly Patron, certain special abilities that aren't limited in uses per day, lots of manipulation and control abilities. But I don't think that's what you're going for.
Mechanically, the Kinecticist is nearly a Warlock. Most of his abilities are unlimited use, he has a thematic and modifiable blast power as one of the cornerstones of his class, his utility powers will vastly differentiate one from another. You might want to consider it.