hardhat-spdx-license-identifier/src/tasks/prepend_spdx_license.ts

Prepend local Solidity source files with an SPDX License Identifier

import { name as pluginName } from '../../package.json';
import fs from 'fs';
import { TASK_COMPILE_SOLIDITY_GET_SOURCE_PATHS } from 'hardhat/builtin-tasks/task-names';
import { task } from 'hardhat/config';
import { HardhatPluginError } from 'hardhat/plugins';

task(
  'prepend-spdx-license',
  'Prepends SPDX License identifier to local source files',
  async function (args, hre) {
    const config = hre.config.spdxLicenseIdentifier;

    const { license } = JSON.parse(
      fs.readFileSync(`${hre.config.paths.root}/package.json`, 'utf8'),
    );

    if (!license) {
      throw new HardhatPluginError(
        pluginName,
        'no license specified in package.json, unable to add SPDX License Identifier to sources',
      );
    }

    // TODO: forward args from compile task if applicable
    const sourcePaths: string[] = await hre.run(
      TASK_COMPILE_SOLIDITY_GET_SOURCE_PATHS,
      args,
    );

    const headerBase = '// SPDX-License-Identifier:';
    const regexp = new RegExp(`(${headerBase}.*\n*)?`);
    const header = `${headerBase} ${license}\n`;

    let count = 0;

    await Promise.all(
      sourcePaths.map(async (sourcePath) => {
        if (config.only.length && !config.only.some((m) => sourcePath.match(m)))
          return;
        if (
          config.except.length &&
          config.except.some((m) => sourcePath.match(m))
        )
          return;

        // content is read from disk for preprocessor compatibility
        const content = fs.readFileSync(sourcePath).toString();

        const partialMatch = content.startsWith(headerBase);
        const exactMatch = content.startsWith(header);

        if (exactMatch) return;
        if (partialMatch && !hre.config.spdxLicenseIdentifier.overwrite) return;

        const padding = partialMatch ? '' : '\n';

        fs.writeFileSync(sourcePath, content.replace(regexp, header + padding));
        count++;
      }),
    );

    if (count > 0) {
      console.log(
        `Prepended SPDX License Identifier "${license}" to ${count} sources.`,
      );
    }
  },
);