Q3.php

<?php

declare(strict_types=1);

function parse(string $data): array {
  $lines = explode("\n", trim($data));
  return [
    base64_decode(implode(array_slice($lines, 0, -6))),
    array_combine(
      array_map(base64_decode(...), array_slice($lines, -6, 3)),
      array_map(base64_decode(...), array_slice($lines, -3, 3)),
    ),
  ];
}

function stretch(string $source): string {
  $x = '';
  $y = '';
  $z = true;
  for ($i = 0; $i < strlen($source); $i++) {
    if ($i % 3 === 2) {
      $y .= $source[$i] ^ '_';
      $x .= '_';
      $z = !$z;
    } else if ($i % 2 === ($z?0:1)) {
      $y .= $source[$i] ^ "\n";
      $x .= "\n";
    } else {
      $y .= "\n";
      $x .= $source[$i] ^ "\n";
    }
  }
  $result = '';
  $result .= "'$x";
  $result .= match (strlen($x) % 3) {
    0 => "\n'^",
    1 => "'^",
    2 => "'\n^\043",
  };
  $result .= "\n'$y";
  $result .= match (strlen($y) % 3) {
    0 => "'",
    1 => "\n'\043",
    2 => "'\043",
  };
  return $result;
}

function convert(string $file_path, string $template, array $replacements): void {
  if (str_ends_with($file_path, '.blade.php')) return;
  if (str_ends_with($file_path, '.html.php')) return;
  if (str_ends_with($file_path, '.svg.php')) return;

  $file_content = file_get_contents($file_path);
  assert($file_content !== false);
  if (!str_starts_with($file_content, "\043!") && !str_starts_with($file_content, '<?'))
    return;

  $php_source = str_replace(
    '2023',
    stretch(bin2hex(strtr($file_content, $replacements))),
    $template,
  );
  rename($file_path, "{$file_path}.erkaigi.bak");
  file_put_contents($file_path, $php_source);
}

function verify(string $s): bool {
  $len = strlen($s);
  if ($len % 3 !== 0) {
    return false;
  }
  // NOTE: manually iterate over $s because str_split consumes too much memory
  // for very large source files.
  for ($i = 0; $i < $len/3; $i++) {
    $a = $s[3*$i + 0];
    $b = $s[3*$i + 1];
    $c = $s[3*$i + 2];
    if (
      $a === "\n" || $a === "\r" || $a === " " || $a === "\t" ||
      $b === "\n" || $b === "\r" || $b === " " || $b === "\t" ||
      $c !== "\n"
    ) {
      return false;
    }
  }
  return true;
}

function cmd_convert(string $repo_dir): void {
  $fp = fopen(__FILE__, 'r');
  fseek($fp, __COMPILER_HALT_OFFSET__);
  $data = stream_get_contents($fp);
  fclose($fp);
  [$template, $replacements] = parse($data);

  $iter = new RecursiveDirectoryIterator($repo_dir, RecursiveDirectoryIterator::CURRENT_AS_PATHNAME);
  $iter = new RecursiveIteratorIterator($iter);
  $iter = new RegexIterator($iter, '|\.php$|');

  convert("{$repo_dir}/artisan", $template, $replacements);
  foreach ($iter as $file_path) {
    convert($file_path, $template, $replacements);
  }
}

function cmd_revert(string $repo_dir): void {
  $iter = new RecursiveDirectoryIterator($repo_dir, RecursiveDirectoryIterator::CURRENT_AS_PATHNAME);
  $iter = new RecursiveIteratorIterator($iter);
  $iter = new RegexIterator($iter, '|\.erkaigi\.bak$|');

  foreach ($iter as $path) {
    rename($path, str_replace('.erkaigi.bak', '', $path));
  }
}

function cmd_verify(string $repo_dir): void {
  $iter = new RecursiveDirectoryIterator($repo_dir, RecursiveDirectoryIterator::CURRENT_AS_PATHNAME);
  $iter = new RecursiveIteratorIterator($iter);
  $iter = new RegexIterator($iter, '|\.erkaigi\.bak$|');

  foreach ($iter as $backup_file_path) {
    $compiled_file_path = str_replace('.erkaigi.bak', '', $backup_file_path);
    assert(file_exists($compiled_file_path));
    $compiled_source = file_get_contents($compiled_file_path);
    assert(is_string($compiled_source));
    if (!verify($compiled_source)) {
      fwrite(STDERR, "'{$compiled_file_path}' is invalid.\n");
      exit(1);
    }
  }
}

function cmd_help(): void {
  echo <<<'EOS'
    Usage: php Q3.php <subcommand>

    Subcommands:
      convert      Stretch Laravel sources.
      revert       Revert changes.
      verify       Check if all sources are stretched.
      help         Show this help.

    Local:
       1. Install PHP 8.2.1.
       2. Install Composer.
       3. git clone --depth=1 --branch=v9.5.0 https://github.com/laravel/laravel.git
       4. cp -f Q3.composer.json laravel/composer.json
       5. cp -f Q3.composer.lock laravel/composer.lock
       6. cd laravel
       7. composer install --prefer-dist --no-dev
       8. cp -f .env.example .env
       9. php artisan key:generate --ansi
      10. php artisan serve
      11. Access http://localhost:8000. This "warm-up" is needed for some reason.
      12. php ../Q3.php convert .
      13. php -d ffi.enable=1 -d opcache.enable=0 -d short_open_tag=1 artisan serve

    Docker:
       1. Install Docker.
       2. docker build -f Q3.Dockerfile --tag=phperkaigi-2023-q3 .
       3. docker run --rm -it -p 8000:8000 phperkaigi-2023-q3 bash
       4. cd laravel
       5. php artisan serve --host=0.0.0.0 --port=8000
       6. Access http://localhost:8000. This "warm-up" is needed for some reason.
       7. php ../Q3.php convert .
       8. php -d ffi.enable=1 -d opcache.enable=0 -d short_open_tag=1 artisan serve --host=0.0.0.0 --port=8000

    NOTE:
      Because this program depends on PHP internal and CPU architecture, it may not
      work on your environment. If so, please read this source code and find
      the embedded token.

    EOS;
}

if (PHP_VERSION !== '8.2.1') {
  fputs(STDERR, "This program supports only PHP 8.2.1.\n");
}
if (!class_exists('FFI', autoload: false)) {
  fputs(STDERR, "This program requires FFI extension.\n");
}

$cmd = $argv[1] ?? 'help';
$repo_dir = $argv[2] ?? 'laravel';

match ($cmd) {
  'convert' => cmd_convert($repo_dir),
  'revert' => cmd_revert($repo_dir),
  'verify' => cmd_verify($repo_dir),
  'help' => cmd_help(),
  default => cmd_help(),
};
__halt_compiler();
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