trufflesuite/truffle

module.exports = async function (options) {
  const SUPPORTED_COMPILERS = ["--solc"];
  const Config = require("@truffle/config");
  const config = Config.default().with(options);

  config.events.emit("obtain:start");

  if (options.solc) {
    return await downloadAndCacheSolc({ config, options });
  }

  const message =
    `You have specified a compiler that is unsupported by ` +
    `Truffle.\nYou must specify one of the following ` +
    `compilers as well as a version as arguments: ` +
    `${SUPPORTED_COMPILERS.join(", ")}\nSee 'truffle help ` +
    `obtain' for more information and usage.`;
  throw new Error(message);
};

const downloadAndCacheSolc = async ({ config, options }) => {
  const { CompilerSupplier } = require("@truffle/compile-solidity");
  const semver = require("semver");
  const { events } = config;

  const version = options.solc;
  if (!version || !semver.validRange(version)) {
    const message =
      `You must specify a valid solc version to download` +
      `You specified: "${version}".`;
    throw new Error(message);
  }

  try {
    const supplier = new CompilerSupplier({
      events,
      solcConfig: {
        ...config.compilers.solc,
        version
      }
    });
    const { solc } = await supplier.load();
    events.emit("obtain:succeed", {
      compiler: {
        version: solc.version(),
        name: "Solidity"
      }
    });
    return;
  } catch (error) {
    events.emit("obtain:fail");
    return;
  }
};