# cargo-ohos
Cross-compile Rust for OpenHarmony. Sets up the environment for cargo, cc-rs, bindgen,
cmake-rs and pkg-config from the OpenHarmony SDK.
## Usage
```sh
export OHOS_SDK_NATIVE=/path/to/ohos-sdk/native
cargo ohos build -t aarch64 --release
```
The SDK can also be discovered from `DEVECO_SDK_HOME` or the standard DevEco Studio installation location
(currently only macOS)
### Prebuilt LLVM toolchains
It's generally recommend to use the LLVM toolchain bundled with the OpenHarmony SDK.
However, if a newer LLVM version is required, it's possible to use a prebuilt version
mirrored from
[openharmony-rs/ohos-llvm-toolchains](https://github.com/openharmony-rs/ohos-llvm-toolchains).
Use --download-prebuilt and pass the expected major version.
At the time of writing only version 19 is supported, but future upstream release might make
more versions available.
```sh
cargo ohos build --download-prebuilt=19 --release
```
The archive is verified against the SHA-256 digest published by GitHub.
When the `gh` CLI is installed and authenticated, its GitHub artifact attestation must also
identify the mirror repository's `mirror.yml` workflow on `main` as the signer.
This attests the mirroring and validation workflow, not how OpenHarmony originally built the toolchain.
The verified toolchain is by default located under
`$XDG_CACHE_HOME/cargo-ohos/ohos-llvm` (or `~/.cache/cargo-ohos/ohos-llvm`) on Linux,
`~/Library/Caches/cargo-ohos/ohos-llvm` on macOS, and
`%LOCALAPPDATA%\cargo-ohos\ohos-llvm` on Windows.
An absolute `XDG_CACHE_HOME` takes precedence on every platform.
A regular OpenHarmony SDK is still required for the sysroot.
Set the option for all invocations with:
```sh
export CARGO_OHOS_DOWNLOAD_PREBUILT=19
```
`--download-prebuilt` replaces `--llvm`/`OHOS_LLVM`. If GitHub's anonymous API rate limit is
insufficient, `cargo-ohos` and `gh` use `GITHUB_TOKEN` when it is set.
## License
MIT OR Apache-2.0