chainscript/lib/utils/writeToPDF.js

Client for chainscript.io

'use strict';

exports.__esModule = true;
exports['default'] = writeToPDF;

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { 'default': obj }; }

var _fs = require('fs');

var _fs2 = _interopRequireDefault(_fs);

/**
 * This could be improved by not putting the entire PDF in a buffer.
 */

function writeToPDF(input, output, script) {
  return new Promise(function (resolve, reject) {
    var reader = typeof input === 'string' ? _fs2['default'].createReadStream(input) : input;

    var buffer = new Buffer([]);

    reader.on('error', reject);

    reader.on('data', function (data) {
      return buffer = Buffer.concat([buffer, data]);
    });

    reader.on('end', function () {
      var start = buffer.indexOf('\n% Chainscript: ');
      var end = undefined;

      if (start < 0) {
        var pos = 0;

        do {
          pos = buffer.indexOf('startxref', pos + 9);

          if (pos >= 0) {
            start = end = pos;
          }
        } while (pos >= 0);

        if (start < 0) {
          reject(new Error('Could not find startxref'));
          return;
        }
      } else {
        end = buffer.indexOf('\n', start + 16) + 1;
      }

      var writer = typeof output === 'string' ? _fs2['default'].createWriteStream(output, {
        defaultEncoding: 'binary',
        mode: 420
      }) : output;

      writer.on('error', reject);
      writer.write(buffer.slice(0, start));

      if (script) {
        writer.write('\n% Chainscript: ' + JSON.stringify(script) + '\n');
      }

      writer.end(buffer.slice(end), resolve);
    });
  });
}

module.exports = exports['default'];