# Gear WASM Builder

This is a helper crate that can be used in build scripts for building Gear programs.

## Usage

1. Add the `gear-wasm-builder` crate as a build dependency to the `Cargo.toml`:

```toml
# ...

[build-dependencies]
gear-wasm-builder = "0.1.2"

# ...
```

2. Create a `build.rs` file and place it at the directory with `Cargo.toml`:

```rust
fn main() {
    gear_wasm_builder::build();
}
```

3. Use `cargo` as usually:

```bash
cargo clean
cargo build
cargo build --release
cargo test
cargo test --release
```

4. Find the built WASM binaries in `target/wasm32-gear/<profile>` directory:

- `.wasm` — original WASM built from the source files
- `.opt.wasm` — optimised WASM binary to be submitted to the blockchain

5. Also, you can include a generated `wasm_binary.rs` source file to use the WASM code while e.g. writing tests. When
   doing this, you need to use some feature which will be excluded from passing it down to the build process triggered
   by the build script. By default, this is the `std` feature. If you want to use a custom feature for that, use one of
   the the `build_XXX_custom` functions in your `build.rs`

```rust
#[cfg(feature = "std")]
mod code {
    include!(concat!(env!("OUT_DIR"), "/wasm_binary.rs"));
}

#[test]
fn debug_wasm() {
    assert_eq!(
        std::fs::read("target/wasm32-gear/debug/test_program.wasm").unwrap(),
        code::WASM_BINARY,
    );
    assert_eq!(
        std::fs::read("target/wasm32-gear/debug/test_program.opt.wasm").unwrap(),
        code::WASM_BINARY_OPT,
    );
}
```

## License

Source code is licensed under `GPL-3.0-or-later WITH Classpath-exception-2.0`.
