IOS Test Harness

Overview This directory contains an iOS testing harness that can be run on osx and ios. Under the hood our client libraries can be built as a staticlib and c bindings are exposed via FFI. This enables the library to be linked with an iOS application build.

The primary method for xcode to link external libraries is via a concept called XCFramework. We generate an XCFramework when building for iOS, it is stored in the target/aarch64-apple-ios/release directory. See the makefile for more details.

Usage

1. Ensure xcode is installed
2. Setup local notary via the notary docs
3. Open xcode and the client_ios/demo project
4. Run make ios-sim if running in the simulator, or make ios for on device testing
5. Return to xcode and select Product > Run or cmd+R
6. Click setup tracing to enable logging, then generate proof

Advanced Notes

Module Map Files XCode relies on a concept called modules which use a modulemap file to describe the connection between a standalone C library and a swift or objective-c application.

Web prover use a default module map file which simply exposes are library as a framework called Prover, exposed c-bindings can be called on this interface.

Linking dependencies Our static library depends on the -lstdc++ or -lc++ library, link either when using xcode. The default project settings in the demo harness should already link this library.

If it has not been linked, you may see a linking error such as: error build: Undefined symbol: std::exception::what() const

To remedy:

1. Open xcode
2. Select Demo > Build Settings > Other Linker Flags
3. Click + and add -lstdc++ as a flag

Listing linking dependencies The rust compiler has a special flag --print=native-static-libs for listing the linking dependencies of a static library. This can be helpful for identifying missing linker flags.

To use:

1. Run cargo clean (the command only works when rustc builds)
2. Prepend RUSTFLAGS="--print=native-static-libs" to the cargo build command for the ios target.
3. Search for native-static-libs: to view a list of linker flags

For example, this output was shown at testing time: note: native-static-libs: -framework Security -framework CoreFoundation -lc++ -liconv -lSystem -lc -lm

Most of these appears to already be linked by xcode, but -lc++ in particular was missing.

Local certificate chain The demo harness has been setup to work with localhost services using TLS, this requires loading a certificate into the TLS client. It currently relies on the demo/ca-cert.cer, this is identical to the certificate in the fixtures directory.

If that certificate changes, both will need updated.