iOS/Android support

[ospfranco]

I'm trying to build static library (.a) that I can use on iOS and Android. I'm trying to compile the C experimental bindings, doing cargo build --target [TARGET] --release works and compiles the library correctly.

The problem however lies when I try to create all three iOS archs (x86_64-apple-ios, aarch64-apple-ios, aarch64-apple-ios-sim) and then generate a single fat binary for x86_64-apple-ios and aarch64-apple-ios-sim, which is needed to package all of them in a single .xcframework

I get the following error:

lipo -create ../../target/x86_64-apple-ios/release/libsql_experimental.a ../../target/aarch64-apple-ios-sim/release/libsql_experimental.a -output generated/simulator_fat/libsql_experimental.a
fatal error: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/lipo: archive member ../../target/x86_64-apple-ios/release/libsql_experimental.a(sqlite3mc.c.o) cputype (16777228) and cpusubtype (0) does not match previous archive members cputype (16777223) and cpusubtype (3) (all members must match)
make: *** [libsql.xcframework] Error 1

Which seems to indicate the sqlite3mc.c object file has not been compiled for the correct architecture.

Are there some instructions to compile the library to iOS/Android? I've seen at least one person that has managed to compile it for Android.

[haaawk]

I successfully ran libsql on Android. I don't think I had to do anything special. What I do though is having a new Rust lib project that depends on libsql.

[ospfranco]

Running lipo on the generated .a for x86_64 allowed me to pin point the problem:

lipo -info ../../target/x86_64-apple-ios/release/libsql_experimental.a                                                                                   
fatal error: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/lipo: archive member ../../target/x86_64-apple-ios/release/libsql_experimental.a(sqlite3mc.c.o) cputype (16777228) and cpusubtype (0) does not match previous archive members cputype (16777223) and cpusubtype (3) (all members must match)

Indeed it seems the cargo build is targeting apple ios x86_64 but the generated sqlite object file has been compiled for another arch. Looking at the build script I find nothing weird. The cc crate is used for compiling the sqlite source file which should handle cross compilation gracefully. So it seems this path with a cmake build is happening (maybe due the encryption feature being turned on?).

I've added the following to try to make cross compilation work, but it doesn't seem to be doing anything:

if target.contains("x86_64-apple-ios") {
    cmake_opts.push(&cmake_toolchain_opt);
    writeln!(toolchain_file, "set(CMAKE_SYSTEM_NAME \"iOS\")").unwrap();
    writeln!(toolchain_file, "set(CMAKE_SYSTEM_PROCESSOR \"x86_64\")").unwrap();
}

Edit: turning off the encryption feature does indeed allow the crate to compile successfully. Seems indeed the cmake compilation is off for non-host architectures.