iOS Mobile Builds For libp2p

cbind/libp2p.nim is the supported C ABI target for iOS builds.

Supported Targets

The iOS build targets iOS 13.0 or newer by default and uses SDKs from an installed Xcode bundle:

Target	Nim CPU	SDK	Clang target
iOS device `arm64`	`arm64`	`iphoneos`	`arm64-apple-ios13.0`
iOS simulator `arm64`	`arm64`	`iphonesimulator`	`arm64-apple-ios13.0-simulator`

These targets must be built on macOS with Xcode installed. They are not exposed on Linux Nix hosts because the iPhoneOS and iPhoneSimulator SDKs are provided by Xcode, not by nixpkgs.

Build Commands

Build a single target on macOS:

nix build .#cbind-ffi-ios-arm64
nix build .#cbind-ffi-ios-simulator-arm64

Build both iOS layouts in one output:

nix build .#cbind-ffi-ios

If your Nix installation uses sandboxing on macOS, disable it for this build so the derivation can access the host Xcode bundle and SDKs:

nix --extra-experimental-features "nix-command flakes" \
  --option sandbox false \
  build .#cbind-ffi-ios-arm64

Artifact Layout

Single-target outputs are flat:

result/
  bin/libp2p_ios_check
  include/libp2p.h
  include/nim_ffi_cbor.h
  include/nim_ffi_prelude.h
  include/tinycbor/...
  include/cddl_bindings/libp2p.cddl
  lib/liblibp2p.dylib
  lib/liblibp2p.a
  nix-support/ios-target

The aggregate output nests the same layout by target:

result/ios/arm64/...
result/ios/simulator-arm64/...

liblibp2p.dylib and liblibp2p.a intentionally keep the same naming as the host cbind package.

Downstream Linking Notes

Use the generated high-level C helpers in include/libp2p.h:

libp2p_ctx_create
libp2p_ctx_start
libp2p_ctx_stop
libp2p_ctx_destroy

The generated header uses TinyCBOR for request and response encoding. The Nix output installs the required TinyCBOR headers and C sources under include/tinycbor. Downstream C, C++, Objective-C, or Swift wrapper code that calls the generated helper functions should compile those TinyCBOR .c files into the app or a support library.

For shared-library linking, package the matching target's lib/liblibp2p.dylib with the iOS application using the normal Xcode embedding/signing flow. For static linking, link lib/liblibp2p.a together with the C++ runtime selected by the application.

iOS Check Harness

The Nix iOS derivation compiles cbind/examples/libp2p_mobile_check.c for each target. The harness includes the generated nim-ffi C header, creates a default TCP/Yamux node, starts it, stops it, destroys the context, and fails on callback errors or timeouts.

The derivation only compiles and links the harness. It does not run the harness on a simulator or physical device.

CI Coverage

.github/workflows/mobile_ios.yml runs on macOS and builds both iOS packages. The workflow checks that each output contains:

shared and static liblibp2p libraries
generated C headers and CDDL
TinyCBOR headers used by the generated C helper layer
the linked iOS check executable
Mach-O platform metadata matching the selected SDK
arm64 architecture metadata for the dynamic library, static library, and check executable

3.2 KiB Raw Permalink Blame History