iPhone SDK Prediction

John Gruber has an article in which he talks about what Apple will announce on Thursday; specifically, what features the iPhone SDK will - or won't - provide. He writes:

If it's true that the dock connector is off-limits, that's unfortunate, but also not surprising – clearly a big part of what Apple's been working on in advance of this SDK are ways to sandbox applications for security and control of resources.

His suspicion that there will be a sandbox is based on this article by Jeremy Horowitz. But Horowitz writes:

Under current plans, SDK developers will be prevented from interfacing directly with Dock Connector-based accessories connected to the iPhone or iPod touch

He doesn't explain how developers will be prevented from interfacing with the Dock connector. A bit further up in his article, Horowitz writes:

The most controversial aspect of Apple's SDK plan is its intention to formally approve or deny all SDK-based software releases for its devices. Our sources confirm that Apple will act as a gatekeeper for applications, deciding which are and are not worthy of release, and publishing only approved applications to the iTunes Store

Personally, I find it unlikely that Apple created a sandbox for third-party apps. Adding sandboxes to existing environments is hard. Java's sandbox was part of the design from the get-go; Objective-C, on the other hand, is basically C plus a bunch of features adding support for object-oriented programming. Attempting to sandbox C seems - at first glance - a bit futile.

In my opinion, a more likely solution to preventing stuff Apple doesn't want is not through a sandbox, but through the approvement process. I would not be surprised if developers get full access to the iPhone's APIs, but Apple will simply not publish software which doesn't adhere to their guidelines.

On the other hand, sandboxing Objective-C is not actually impossible. One possible solution to sandboxing C in the iPhone would be to run third-party apps in a VM. Apple owns LLVM, which could possibly be used to sandbox Objective-C code in the iPhone. According to John Siracusa, Apple "recently did some extensive work on the LLVM ARM backend." He suspects it's because LLVM was used to improve performance on the iPhone; maybe it's for the SDK?

We'll see next Thursday, I guess.