kabiroberai

I’m also one of the maintainers of Theos :)

When you use Theos outside macOS, you have to install a toolchain and SDK. The toolchain is built from LLVM + cctools, and is in fact very similar to the one we use in xtool (I maintain both.) The SDK is hosted on GitHub and I could’ve decided to use this instead of getting the user to supply a copy of Xcode, but the copyright status is iffy; there’s an argument to be made in light of Google v. Oracle but I didn’t want to take any chances.

I looked into streaming but afaict the XIP format doesn’t support random access the same way that ZIP does. specifically because 1) it doesn’t seem to have a Central Directory like ZIP and 2) it has an optimization where files can be hardlinks to other files (by ID) in the XIP, so if you want to extract a file but all you get is a hardlink ID, you can’t expand the contents until you encounter and expand the hardlink pointee. it’s possible I’ve missed something, open to ideas for sure.

xtool creator here, this is correct. it wouldn’t have been possible to support Linux if xtool was just a layer on top of Xcode, as Xcode doesn’t run on Linux.

we only need Xcode to be installed on macOS since it bundles the iOS SDK (ie all the header files.) similarly, we ask the user to supply a copy of Xcode.xip during the setup process on Linux in order to extract the SDK.

it definitely depends on your definition of “replacement” in the end, but I (and most people I’ve spoken with in the iOS community) would consider “Xcode” to be the Xcode build system, user interface, and proprietary tooling. xtool doesn’t rely on any of this, not even for signing and installation. you can (read: must on Linux, may on macOS) use it with the open-source Swift and Clang toolchain + LLVM’s LLD linker and MachO tooling. Codesigning uses zsign, an MIT-licensed x-platform codesign alternative, and installation relies on the open source libimobiledevice project, which is installed by default on many Linux distributions (eg Ubuntu).