code: function getProcessor(encoding) {
      var result;
      if (/^[\w-_]+$/.test(encoding)) { // 标准编码器
        result = processors[encoding];
        if (result) {
          return result;
        }
        var file = path.join(__dirname, '../processor-extend', 'processor-' + encoding + '.js');
        if (fs.existsSync(file)) {
          processors[encoding] = require(file);
          return processors[encoding];
        }
        console.warn(
          colors.blue(
            'Processor "%s" is not registered.'
          ), encoding
        );
        return;
      }
      var item = processors[encoding];
      if (item) {
        if (item.cacheKey === cacheKeys[encoding]) { // 处理缓存
          return item.processor;
        }
        else {
          processors[encoding] = null;
        }
      }
      var body = execImport(encoding);
      if (!body || body.indexOf('function') < 0) {
        console.error(colors.red('Invalid encoding %j.'), encoding);
        return function (content) {
          return content;
        };
      }
      result = buildProcessor(body);
      if (/^[#@]/.test(encoding)) { // 缓存编码
        cacheKeys[encoding] = guid++;
        processors[encoding] = {
          cacheKey: cacheKeys[encoding],
          processor: result
        };
      }
      return result;
    }
docs: 获取处理器
  
  @inner
  @param {string} encoding 编码名称
  @return {Function} 返回名称对应的处理器，如果没有找到则返回 undefined