Support napi inside of bun:ffi

[Jarred-Sumner]

What does this PR do?

This makes it easier to return strings from bun:ffi to JavaScript, by allowing you to go through the napi code path to do so.

Example C:

#include <node/node_api.h>

napi_value napi(napi_env env) {
  napi_value result;
  napi_create_string_utf8(env, "Hello, Napi!", NAPI_AUTO_LENGTH, &result);
  return result;
}

JS usage:

import { cc } from "bun:ffi";
import source from "./hello-napi.c" with { type: "file" };
const {
  symbols: { napi },
} = cc({
  source,
  symbols: {
    "napi": {
      args: ["napi_env"],
      returns: "napi_value",
    },
  },
});

if (napi() !== "Hello, Napi!") {
  throw new Error("napi() !== Hello, Napi!");
}

How did you verify your code works?

Updated a test

[robobun]

❌ @Jarred-Sumner, your commit 04d6ea2 has 13 failures in #3598:

test/js/web/streams/streams.test.js - 1 failing on 🍎 14 x64

test/js/node/watch/fs.watch.test.ts - timeout on 🍎 14 x64

test/integration/next-pages/test/dev-server.test.ts - 1 failing on 🍎 14 x64

test/js/third_party/@azure/service-bus/azure-service-bus.test.ts - 1 failing on 🐧 12 x64-baseline

test/cli/install/migration/complex-workspace.test.ts - timeout on 🐧 12 x64

test/js/node/fs/fs.test.ts - timeout on 🪟 x64-baseline

test/js/web/fetch/fetch-tcp-stress.test.ts - timeout on 🍎 13 aarch64

test/js/web/fetch/fetch-tcp-stress.test.ts - timeout on 🍎 14 x64

test/js/web/fetch/fetch-tcp-stress.test.ts - timeout on 🍎 13 x64

test/js/node/test/parallel/fs-watch-recursive-add-folder.test.js - 1 failing on 🍎 14 aarch64

test/js/bun/http/fetch-file-upload.test.ts - 1 failing on 🪟 x64

test/cli/watch/watch.test.ts - 2 failing on 🪟 x64

test/cli/watch/watch.test.ts - 2 failing on 🪟 x64-baseline

test/cli/hot/watch.test.ts - 1 failing on 🪟 x64-baseline

test/cli/hot/watch.test.ts - 1 failing on 🪟 x64

test/cli/install/bun-link.test.ts - 1 failing on 🪟 x64-baseline

test/js/bun/http/bun-serve-static.test.ts - 1 failing on 🍎 14 aarch64

test/js/bun/http/bun-serve-static.test.ts - 2 failing on 🍎 13 aarch64

[dylan-conway]

is this going to segfault in the handle scope code?

[Jarred-Sumner]

discussed IRL

[codehz]

is it possible to receive argument via napi?
I mean the "napi_callback_info"

https://www.npmjs.com/package/bigint-buffer <- a 281562 weekly download library is just used for convert between bigint and buffer
and the source code is here: https://github.com/no2chem/bigint-buffer/blob/master/src/bigint-buffer.c