Files
yaak-mountain-loop/crates/yaak-wasm/build-wasm.cjs
T

80 lines
2.9 KiB
JavaScript

const { execSync, spawnSync } = require("node:child_process");
const fs = require("node:fs");
const os = require("node:os");
const path = require("node:path");
// Same shape as crates/yaak-templates/build-wasm.cjs, plus one wrinkle: this
// crate links SQLite, and sqlite-wasm-rs compiles sqlite3.c to wasm at build
// time. That needs a C compiler with a WebAssembly backend, which Apple's
// clang is not. So the build looks for one, and when it finds none it keeps
// the committed pkg/ and says so — desktop developers never need this crate
// rebuilt, and failing their `npm run bootstrap` over it would be wrong.
if (process.env.SKIP_WASM_BUILD === "1") {
console.log("Skipping wasm-pack build (SKIP_WASM_BUILD=1)");
return;
}
/** A clang that can emit wasm32, or null. */
function findWasmClang() {
const candidates = [
process.env.CC_wasm32_unknown_unknown,
"/opt/homebrew/opt/llvm/bin/clang", // Homebrew LLVM, Apple Silicon
"/usr/local/opt/llvm/bin/clang", // Homebrew LLVM, Intel
"clang", // Linux distros' clang usually has the backend built in
].filter(Boolean);
for (const clang of candidates) {
const probe = spawnSync(clang, ["--print-targets"], { encoding: "utf8" });
if (probe.status === 0 && /\bwasm32\b/.test(probe.stdout)) return clang;
}
return null;
}
const clang = findWasmClang();
if (clang == null) {
console.log(
[
"yaak-web: no C compiler with a WebAssembly backend found; keeping the committed pkg/.",
" To rebuild: install LLVM (macOS: `brew install llvm`) or point CC_wasm32_unknown_unknown at one.",
].join("\n"),
);
return;
}
// llvm-ar lives next to clang in every LLVM distribution
const ar = path.join(path.dirname(clang), "llvm-ar");
// Remap machine-specific paths that rustc embeds into the binary (panic
// location strings), so builds are reproducible across machines
const sysroot = execSync("rustc --print sysroot").toString().trim();
const cargoHome = process.env.CARGO_HOME ?? path.join(os.homedir(), ".cargo");
execSync("wasm-pack build --target bundler", {
stdio: "inherit",
cwd: __dirname,
env: {
...process.env,
CC_wasm32_unknown_unknown: clang,
AR_wasm32_unknown_unknown: fs.existsSync(ar) ? ar : (process.env.AR_wasm32_unknown_unknown ?? ""),
RUSTFLAGS: `--remap-path-prefix=${cargoHome}=/cargo --remap-path-prefix=${sysroot}=/rustc`,
},
});
// Rewrite the generated entry to use Vite's ?init import style instead of
// the ES Module Integration style that wasm-pack generates, which Vite/rolldown
// does not support in production builds.
const entry = path.join(__dirname, "pkg", "yaak_web.js");
fs.writeFileSync(
entry,
[
'import init from "./yaak_web_bg.wasm?init";',
'export * from "./yaak_web_bg.js";',
'import * as bg from "./yaak_web_bg.js";',
'const instance = await init({ "./yaak_web_bg.js": bg });',
"bg.__wbg_set_wasm(instance.exports);",
"instance.exports.__wbindgen_start();",
"",
].join("\n"),
);