@nraynaud/xo-vhdmount/dist/vhd.js

'use strict';

var _promise = require('babel-runtime/core-js/promise');

var _promise2 = _interopRequireDefault(_promise);

var _regenerator = require('babel-runtime/regenerator');

var _regenerator2 = _interopRequireDefault(_regenerator);

var _asyncToGenerator2 = require('babel-runtime/helpers/asyncToGenerator');

var _asyncToGenerator3 = _interopRequireDefault(_asyncToGenerator2);

var _classCallCheck2 = require('babel-runtime/helpers/classCallCheck');

var _classCallCheck3 = _interopRequireDefault(_classCallCheck2);

var _createClass2 = require('babel-runtime/helpers/createClass');

var _createClass3 = _interopRequireDefault(_createClass2);

var _typeof2 = require('babel-runtime/helpers/typeof');

var _typeof3 = _interopRequireDefault(_typeof2);

var _structFu = require('@nraynaud/struct-fu');

var _structFu2 = _interopRequireDefault(_structFu);

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

var VHD_UTIL_DEBUG = 0;
var debug = VHD_UTIL_DEBUG ? function (str) {
  return console.log('[vhd-util]' + str);
} : function () {};

// ===================================================================
//
// Spec:
// https://www.microsoft.com/en-us/download/details.aspx?id=23850
//
// C implementation:
// https://github.com/rubiojr/vhd-util-convert
//
// ===================================================================

// Sizes in bytes.
var VHD_FOOTER_SIZE = 512;
var VHD_HEADER_SIZE = 1024;
var VHD_SECTOR_SIZE = 512;

// Block allocation table entry size. (Block addr)
var VHD_ENTRY_SIZE = 4;

var VHD_PARENT_LOCATOR_ENTRIES = 8;
var VHD_PLATFORM_CODE_NONE = 0;

// Types of backup treated. Others are not supported.
var HARD_DISK_TYPE_DYNAMIC = 3; // Full backup.
var HARD_DISK_TYPE_DIFFERENCING = 4; // Delta backup.

// Other.
var BLOCK_UNUSED = 0xFFFFFFFF;
var BIT_MASK = 0x80;

// ===================================================================

var fuFooter = _structFu2.default.struct([_structFu2.default.char('cookie', 8), // 0
_structFu2.default.uint32('features'), // 8
_structFu2.default.uint32('fileFormatVersion'), // 12
_structFu2.default.struct('dataOffset', [_structFu2.default.uint32('high'), // 16
_structFu2.default.uint32('low') // 20
]), _structFu2.default.uint32('timestamp'), // 24
_structFu2.default.char('creatorApplication', 4), // 28
_structFu2.default.uint32('creatorVersion'), // 32
_structFu2.default.uint32('creatorHostOs'), // 36
_structFu2.default.struct('originalSize', [// At the creation, current size of the hard disk.
_structFu2.default.uint32('high'), // 40
_structFu2.default.uint32('low') // 44
]), _structFu2.default.struct('currentSize', [// Current size of the virtual disk. At the creation: currentSize = originalSize.
_structFu2.default.uint32('high'), // 48
_structFu2.default.uint32('low') // 52
]), _structFu2.default.struct('diskGeometry', [_structFu2.default.uint16('cylinders'), // 56
_structFu2.default.uint8('heads'), // 58
_structFu2.default.uint8('sectorsPerTrackCylinder') // 59
]), _structFu2.default.uint32('diskType'), // 60 Disk type, must be equal to HARD_DISK_TYPE_DYNAMIC/HARD_DISK_TYPE_DIFFERENCING.
_structFu2.default.uint32('checksum'), // 64
_structFu2.default.uint8('uuid', 16), // 68
_structFu2.default.char('saved'), // 84
_structFu2.default.char('hidden'), // 85
_structFu2.default.char('reserved', 426) // 86
]);

var fuHeader = _structFu2.default.struct([_structFu2.default.char('cookie', 8), _structFu2.default.struct('dataOffset', [_structFu2.default.uint32('high'), _structFu2.default.uint32('low')]), _structFu2.default.struct('tableOffset', [// Absolute byte offset of the Block Allocation Table.
_structFu2.default.uint32('high'), _structFu2.default.uint32('low')]), _structFu2.default.uint32('headerVersion'), _structFu2.default.uint32('maxTableEntries'), // Max entries in the Block Allocation Table.
_structFu2.default.uint32('blockSize'), // Block size in bytes. Default (2097152 => 2MB)
_structFu2.default.uint32('checksum'), _structFu2.default.uint8('parentUuid', 16), _structFu2.default.uint32('parentTimestamp'), _structFu2.default.uint32('reserved1'), _structFu2.default.char16be('parentUnicodeName', 512), _structFu2.default.struct('parentLocatorEntry', [_structFu2.default.uint32('platformCode'), _structFu2.default.uint32('platformDataSpace'), _structFu2.default.uint32('platformDataLength'), _structFu2.default.uint32('reserved'), _structFu2.default.struct('platformDataOffset', [// Absolute byte offset of the locator data.
_structFu2.default.uint32('high'), _structFu2.default.uint32('low')])], VHD_PARENT_LOCATOR_ENTRIES), _structFu2.default.char('reserved2', 256)]);

// ===================================================================
// Helpers
// ===================================================================

var SIZE_OF_32_BITS = Math.pow(2, 32);
var uint32ToUint64 = function uint32ToUint64(fu) {
  return fu.high * SIZE_OF_32_BITS + fu.low;
};

// Returns a 32 bits integer corresponding to a Vhd version.
var getVhdVersion = function getVhdVersion(major, minor) {
  return major << 16 | minor & 0x0000FFFF;
};

// Sectors conversions.
var sectorsRoundUp = function sectorsRoundUp(bytes) {
  return Math.floor((bytes + VHD_SECTOR_SIZE - 1) / VHD_SECTOR_SIZE);
};
var sectorsRoundUpNoZero = function sectorsRoundUpNoZero(bytes) {
  return sectorsRoundUp(bytes) || 1;
};
var sectorsToBytes = function sectorsToBytes(sectors) {
  return sectors * VHD_SECTOR_SIZE;
};

// Check/Set a bit on a vhd map.
var mapTestBit = function mapTestBit(map, bit) {
  return (map[bit >> 3] << (bit & 7) & BIT_MASK) !== 0;
};
var mapSetBit = function mapSetBit(map, bit) {
  map[bit >> 3] |= BIT_MASK >> (bit & 7);
};

var packField = function packField(field, value, buf) {
  var offset = field.offset;


  field.pack(value, buf, (typeof offset === 'undefined' ? 'undefined' : (0, _typeof3.default)(offset)) !== 'object' ? { bytes: offset, bits: 0 } : offset);
};

var unpackField = function unpackField(field, buf) {
  var offset = field.offset;


  return field.unpack(buf, (typeof offset === 'undefined' ? 'undefined' : (0, _typeof3.default)(offset)) !== 'object' ? { bytes: offset, bits: 0 } : offset);
};
// ===================================================================

// Returns the checksum of a raw struct.
// The raw struct (footer or header) is altered with the new sum.
function checksumStruct(rawStruct, checksumField) {
  var sum = 0;

  // Reset current sum.
  packField(checksumField, 0, rawStruct);

  for (var i = 0; i < VHD_FOOTER_SIZE; i++) {
    sum = sum + rawStruct[i] & 0xFFFFFFFF;
  }

  sum = 0xFFFFFFFF - sum;

  // Write new sum.
  packField(checksumField, sum, rawStruct);

  return sum;
}

function getParentLocatorSize(parentLocatorEntry) {
  var platformDataSpace = parentLocatorEntry.platformDataSpace;


  if (platformDataSpace < VHD_SECTOR_SIZE) {
    return sectorsToBytes(platformDataSpace);
  }

  return platformDataSpace % VHD_SECTOR_SIZE === 0 ? platformDataSpace : 0;
}

// ===================================================================

var Vhd = function () {
  function Vhd(handler, path) {
    (0, _classCallCheck3.default)(this, Vhd);

    this._handler = handler;
    this._path = path;
  }

  // =================================================================
  // Read functions.
  // =================================================================

  // Returns the first address after metadata. (In bytes)


  (0, _createClass3.default)(Vhd, [{
    key: 'getEndOfHeaders',
    value: function getEndOfHeaders() {
      var header = this.header;


      var end = uint32ToUint64(this.footer.dataOffset) + VHD_HEADER_SIZE;

      var blockAllocationTableSize = sectorsToBytes(sectorsRoundUpNoZero(header.maxTableEntries * VHD_ENTRY_SIZE));

      // Max(end, block allocation table end)
      end = Math.max(end, uint32ToUint64(header.tableOffset) + blockAllocationTableSize);

      for (var i = 0; i < VHD_PARENT_LOCATOR_ENTRIES; i++) {
        var entry = header.parentLocatorEntry[i];

        if (entry.platformCode !== VHD_PLATFORM_CODE_NONE) {
          var dataOffset = uint32ToUint64(entry.platformDataOffset);

          // Max(end, locator end)
          end = Math.max(end, dataOffset + getParentLocatorSize(entry));
        }
      }

      debug('End of headers: ' + end + '.');

      return end;
    }

    // Returns the first sector after data.

  }, {
    key: 'getEndOfData',
    value: function getEndOfData() {
      var end = Math.floor(this.getEndOfHeaders() / VHD_SECTOR_SIZE);

      var maxTableEntries = this.header.maxTableEntries;

      for (var i = 0; i < maxTableEntries; i++) {
        var blockAddr = this.readAllocationTableEntry(i);

        if (blockAddr !== BLOCK_UNUSED) {
          // Compute next block address.
          blockAddr += this.sectorsPerBlock + this.sectorsOfBitmap;

          end = Math.max(end, blockAddr);
        }
      }

      debug('End of data: ' + end + '.');

      return sectorsToBytes(end);
    }

    // Returns the start position of the vhd footer.
    // The real footer, not the copy at the beginning of the vhd file.

  }, {
    key: 'getFooterStart',
    value: function () {
      var _ref = (0, _asyncToGenerator3.default)(_regenerator2.default.mark(function _callee() {
        var stats;
        return _regenerator2.default.wrap(function _callee$(_context) {
          while (1) {
            switch (_context.prev = _context.next) {
              case 0:
                _context.next = 2;
                return this._handler.getSize(this._path);

              case 2:
                stats = _context.sent;
                return _context.abrupt('return', stats.size - VHD_FOOTER_SIZE);

              case 4:
              case 'end':
                return _context.stop();
            }
          }
        }, _callee, this);
      }));

      function getFooterStart() {
        return _ref.apply(this, arguments);
      }

      return getFooterStart;
    }()

    // Get the beginning (footer + header) of a vhd file.

  }, {
    key: 'readHeaderAndFooter',
    value: function () {
      var _ref2 = (0, _asyncToGenerator3.default)(_regenerator2.default.mark(function _callee2() {
        var buf, sum, sumToTest, header, sectorsPerBlock, sectorsOfBitmap;
        return _regenerator2.default.wrap(function _callee2$(_context2) {
          while (1) {
            switch (_context2.prev = _context2.next) {
              case 0:
                _context2.next = 2;
                return this._handler.createReadStream(this._path, {
                  start: 0,
                  end: VHD_FOOTER_SIZE + VHD_HEADER_SIZE - 1
                });

              case 2:
                _context2.t0 = _context2.sent;
                _context2.next = 5;
                return streamToBuffer(_context2.t0);

              case 5:
                buf = _context2.sent;
                sum = unpackField(fuFooter.fields.checksum, buf);
                sumToTest = checksumStruct(buf, fuFooter.fields.checksum);

                // Checksum child & parent.

                if (!(sumToTest !== sum)) {
                  _context2.next = 10;
                  break;
                }

                throw new Error('Bad checksum in vhd. Expected: ' + sum + '. Given: ' + sumToTest + '. (data=' + buf.toString('hex') + ')');

              case 10:
                header = this.header = fuHeader.unpack(buf.slice(VHD_FOOTER_SIZE));

                this.footer = fuFooter.unpack(buf);

                // Compute the number of sectors in one block.
                // Default: One block contains 4096 sectors of 512 bytes.
                sectorsPerBlock = this.sectorsPerBlock = Math.floor(header.blockSize / VHD_SECTOR_SIZE);

                // Compute bitmap size in sectors.
                // Default: 1.

                sectorsOfBitmap = this.sectorsOfBitmap = sectorsRoundUpNoZero(sectorsPerBlock >> 3);

                // Full block size => data block size + bitmap size.

                this.fullBlockSize = sectorsToBytes(sectorsPerBlock + sectorsOfBitmap);

                // In bytes.
                // Default: 512.
                this.bitmapSize = sectorsToBytes(sectorsOfBitmap);

              case 16:
              case 'end':
                return _context2.stop();
            }
          }
        }, _callee2, this);
      }));

      function readHeaderAndFooter() {
        return _ref2.apply(this, arguments);
      }

      return readHeaderAndFooter;
    }()

    // Check if a vhd object has a block allocation table.

  }, {
    key: 'hasBlockAllocationTableMap',
    value: function hasBlockAllocationTableMap() {
      return this.footer.fileFormatVersion > getVhdVersion(1, 0);
    }

    // Returns a buffer that contains the block allocation table of a vhd file.

  }, {
    key: 'readBlockTable',
    value: function () {
      var _ref3 = (0, _asyncToGenerator3.default)(_regenerator2.default.mark(function _callee3() {
        var header, offset, size;
        return _regenerator2.default.wrap(function _callee3$(_context3) {
          while (1) {
            switch (_context3.prev = _context3.next) {
              case 0:
                header = this.header;
                offset = uint32ToUint64(header.tableOffset);
                size = sectorsToBytes(sectorsRoundUpNoZero(header.maxTableEntries * VHD_ENTRY_SIZE));
                _context3.next = 5;
                return this._handler.createReadStream(this._path, {
                  start: offset,
                  end: offset + size - 1
                });

              case 5:
                _context3.t0 = _context3.sent;
                _context3.next = 8;
                return streamToBuffer(_context3.t0);

              case 8:
                this.blockTable = _context3.sent;

              case 9:
              case 'end':
                return _context3.stop();
            }
          }
        }, _callee3, this);
      }));

      function readBlockTable() {
        return _ref3.apply(this, arguments);
      }

      return readBlockTable;
    }()

    // Returns the address block at the entry location of one table.

  }, {
    key: 'readAllocationTableEntry',
    value: function readAllocationTableEntry(entry) {
      return this.blockTable.readUInt32BE(entry * VHD_ENTRY_SIZE);
    }

    // Returns the data content of a block. (Not the bitmap !)

  }, {
    key: 'readBlockData',
    value: function () {
      var _ref4 = (0, _asyncToGenerator3.default)(_regenerator2.default.mark(function _callee4(blockAddr) {
        var blockSize, handler, path, blockDataAddr, footerStart, isPadded, size, buf;
        return _regenerator2.default.wrap(function _callee4$(_context4) {
          while (1) {
            switch (_context4.prev = _context4.next) {
              case 0:
                blockSize = this.header.blockSize;
                handler = this._handler;
                path = this._path;
                blockDataAddr = sectorsToBytes(blockAddr + this.sectorsOfBitmap);
                _context4.next = 6;
                return this.getFooterStart();

              case 6:
                footerStart = _context4.sent;
                isPadded = footerStart < blockDataAddr + blockSize;

                // Size ot the current block in the vhd file.

                size = isPadded ? footerStart - blockDataAddr : sectorsToBytes(this.sectorsPerBlock);


                debug('Read block data at: ' + blockDataAddr + '. (size=' + size + ')');

                _context4.next = 12;
                return handler.createReadStream(path, {
                  start: blockDataAddr,
                  end: blockDataAddr + size - 1
                });

              case 12:
                _context4.t0 = _context4.sent;
                _context4.next = 15;
                return streamToBuffer(_context4.t0);

              case 15:
                buf = _context4.sent;

                if (!isPadded) {
                  _context4.next = 18;
                  break;
                }

                return _context4.abrupt('return', Buffer.concat([buf, new Buffer(blockSize - size).fill(0)]));

              case 18:
                return _context4.abrupt('return', buf);

              case 19:
              case 'end':
                return _context4.stop();
            }
          }
        }, _callee4, this);
      }));

      function readBlockData(_x) {
        return _ref4.apply(this, arguments);
      }

      return readBlockData;
    }()

    // Returns a buffer that contains the bitmap of a block.
    //
    // TODO: merge with readBlockData().

  }, {
    key: 'readBlockBitmap',
    value: function () {
      var _ref5 = (0, _asyncToGenerator3.default)(_regenerator2.default.mark(function _callee5(blockAddr) {
        var bitmapSize, offset;
        return _regenerator2.default.wrap(function _callee5$(_context5) {
          while (1) {
            switch (_context5.prev = _context5.next) {
              case 0:
                bitmapSize = this.bitmapSize;
                offset = sectorsToBytes(blockAddr);


                debug('Read bitmap at: ' + offset + '. (size=' + bitmapSize + ')');

                _context5.next = 5;
                return this._handler.createReadStream(this._path, {
                  start: offset,
                  end: offset + bitmapSize - 1
                });

              case 5:
                _context5.t0 = _context5.sent;
                return _context5.abrupt('return', streamToBuffer(_context5.t0));

              case 7:
              case 'end':
                return _context5.stop();
            }
          }
        }, _callee5, this);
      }));

      function readBlockBitmap(_x2) {
        return _ref5.apply(this, arguments);
      }

      return readBlockBitmap;
    }()

    // =================================================================
    // Write functions.
    // =================================================================

    // Write a buffer at a given position in a vhd file.

  }, {
    key: '_write',
    value: function () {
      var _ref6 = (0, _asyncToGenerator3.default)(_regenerator2.default.mark(function _callee6(buffer, offset) {
        return _regenerator2.default.wrap(function _callee6$(_context6) {
          while (1) {
            switch (_context6.prev = _context6.next) {
              case 0:
                return _context6.abrupt('return', this._handler.createOutputStream(this._path, {
                  start: offset,
                  flags: 'r+'
                }).then(function (stream) {
                  return new _promise2.default(function (resolve, reject) {
                    stream.on('error', reject);
                    stream.write(buffer, function () {
                      stream.end();
                      resolve();
                    });
                  });
                }));

              case 1:
              case 'end':
                return _context6.stop();
            }
          }
        }, _callee6, this);
      }));

      function _write(_x3, _x4) {
        return _ref6.apply(this, arguments);
      }

      return _write;
    }()

    // Write an entry in the allocation table.

  }, {
    key: 'writeAllocationTableEntry',
    value: function writeAllocationTableEntry(entry, value) {
      this.blockTable.writeUInt32BE(value, entry * VHD_ENTRY_SIZE);
    }

    // Make a new empty block at vhd end.
    // Update block allocation table in context and in file.

  }, {
    key: 'createBlock',
    value: function () {
      var _ref7 = (0, _asyncToGenerator3.default)(_regenerator2.default.mark(function _callee7(blockId) {
        var offset, blockAddr, blockTable, fullBlockSize, tableOffset, entry;
        return _regenerator2.default.wrap(function _callee7$(_context7) {
          while (1) {
            switch (_context7.prev = _context7.next) {
              case 0:
                // End of file !
                offset = this.getEndOfData();

                // Padded on bound sector.

                if (offset % VHD_SECTOR_SIZE) {
                  offset += VHD_SECTOR_SIZE - offset % VHD_SECTOR_SIZE;
                }

                blockAddr = Math.floor(offset / VHD_SECTOR_SIZE);
                blockTable = this.blockTable;
                fullBlockSize = this.fullBlockSize;

                debug('Create block at ' + blockAddr + '. (size=' + fullBlockSize + ', offset=' + offset + ')');

                // New entry in block allocation table.
                this.writeAllocationTableEntry(blockId, blockAddr);

                tableOffset = uint32ToUint64(this.header.tableOffset);
                entry = blockId * VHD_ENTRY_SIZE;

                // Write an empty block and addr in vhd file.

                _context7.next = 11;
                return this._write(new Buffer(fullBlockSize).fill(0), offset);

              case 11:
                _context7.next = 13;
                return this._write(blockTable.slice(entry, entry + VHD_ENTRY_SIZE), tableOffset + entry);

              case 13:
                return _context7.abrupt('return', blockAddr);

              case 14:
              case 'end':
                return _context7.stop();
            }
          }
        }, _callee7, this);
      }));

      function createBlock(_x5) {
        return _ref7.apply(this, arguments);
      }

      return createBlock;
    }()

    // Write a bitmap at a block address.

  }, {
    key: 'writeBlockBitmap',
    value: function () {
      var _ref8 = (0, _asyncToGenerator3.default)(_regenerator2.default.mark(function _callee8(blockAddr, bitmap) {
        var bitmapSize, offset;
        return _regenerator2.default.wrap(function _callee8$(_context8) {
          while (1) {
            switch (_context8.prev = _context8.next) {
              case 0:
                bitmapSize = this.bitmapSize;

                if (!(bitmap.length !== bitmapSize)) {
                  _context8.next = 3;
                  break;
                }

                throw new Error('Bitmap length is not correct ! ' + bitmap.length);

              case 3:
                offset = sectorsToBytes(blockAddr);


                debug('Write bitmap at: ' + offset + '. (size=' + bitmapSize + ', data=' + bitmap.toString('hex') + ')');
                _context8.next = 7;
                return this._write(bitmap, sectorsToBytes(blockAddr));

              case 7:
              case 'end':
                return _context8.stop();
            }
          }
        }, _callee8, this);
      }));

      function writeBlockBitmap(_x6, _x7) {
        return _ref8.apply(this, arguments);
      }

      return writeBlockBitmap;
    }()
  }, {
    key: 'writeBlockSectors',
    value: function () {
      var _ref9 = (0, _asyncToGenerator3.default)(_regenerator2.default.mark(function _callee9(block, beginSectorId, n) {
        var blockAddr, endSectorId, offset, bitmap, i;
        return _regenerator2.default.wrap(function _callee9$(_context9) {
          while (1) {
            switch (_context9.prev = _context9.next) {
              case 0:
                blockAddr = this.readAllocationTableEntry(block.id);

                if (!(blockAddr === BLOCK_UNUSED)) {
                  _context9.next = 5;
                  break;
                }

                _context9.next = 4;
                return this.createBlock(block.id);

              case 4:
                blockAddr = _context9.sent;

              case 5:
                endSectorId = beginSectorId + n;
                offset = blockAddr + this.sectorsOfBitmap + beginSectorId;


                debug('Write block data at: ' + offset + '. (counter=' + n + ', blockId=' + block.id + ', blockSector=' + beginSectorId + ')');

                _context9.next = 10;
                return this._write(block.data.slice(sectorsToBytes(beginSectorId), sectorsToBytes(endSectorId)), sectorsToBytes(offset));

              case 10:
                _context9.next = 12;
                return this.readBlockBitmap(this.bitmapSize, blockAddr);

              case 12:
                bitmap = _context9.sent;


                for (i = beginSectorId; i < endSectorId; ++i) {
                  mapSetBit(bitmap, i);
                }

                _context9.next = 16;
                return this.writeBlockBitmap(blockAddr, bitmap);

              case 16:
              case 'end':
                return _context9.stop();
            }
          }
        }, _callee9, this);
      }));

      function writeBlockSectors(_x8, _x9, _x10) {
        return _ref9.apply(this, arguments);
      }

      return writeBlockSectors;
    }()

    // Merge block id (of vhd child) into vhd parent.

  }, {
    key: 'coalesceBlock',
    value: function () {
      var _ref10 = (0, _asyncToGenerator3.default)(_regenerator2.default.mark(function _callee10(child, blockAddr, blockId) {
        var blockData, blockBitmap, sectorsPerBlock, i, sectors;
        return _regenerator2.default.wrap(function _callee10$(_context10) {
          while (1) {
            switch (_context10.prev = _context10.next) {
              case 0:
                _context10.next = 2;
                return child.readBlockData(blockAddr);

              case 2:
                blockData = _context10.sent;
                _context10.next = 5;
                return child.readBlockBitmap(blockAddr);

              case 5:
                blockBitmap = _context10.sent;


                debug('Coalesce block ' + blockId + ' at ' + blockAddr + '.');

                // For each sector of block data...
                sectorsPerBlock = child.sectorsPerBlock;
                i = 0;

              case 9:
                if (!(i < sectorsPerBlock)) {
                  _context10.next = 26;
                  break;
                }

                if (mapTestBit(blockBitmap, i)) {
                  _context10.next = 12;
                  break;
                }

                return _context10.abrupt('continue', 23);

              case 12:
                sectors = 0;

                // Count changed sectors.

              case 13:
                if (!(sectors + i < sectorsPerBlock)) {
                  _context10.next = 19;
                  break;
                }

                if (mapTestBit(blockBitmap, sectors + i)) {
                  _context10.next = 16;
                  break;
                }

                return _context10.abrupt('break', 19);

              case 16:
                sectors++;
                _context10.next = 13;
                break;

              case 19:

                // Write n sectors into parent.
                debug('Coalesce block: write. (offset=' + i + ', sectors=' + sectors + ')');
                _context10.next = 22;
                return this.writeBlockSectors({ id: blockId, data: blockData }, i, sectors);

              case 22:

                i += sectors;

              case 23:
                i++;
                _context10.next = 9;
                break;

              case 26:
              case 'end':
                return _context10.stop();
            }
          }
        }, _callee10, this);
      }));

      function coalesceBlock(_x11, _x12, _x13) {
        return _ref10.apply(this, arguments);
      }

      return coalesceBlock;
    }()

    // Write a context footer. (At the end and beginning of a vhd file.)

  }, {
    key: 'writeFooter',
    value: function () {
      var _ref11 = (0, _asyncToGenerator3.default)(_regenerator2.default.mark(function _callee11() {
        var footer, offset, rawFooter;
        return _regenerator2.default.wrap(function _callee11$(_context11) {
          while (1) {
            switch (_context11.prev = _context11.next) {
              case 0:
                footer = this.footer;
                offset = this.getEndOfData();
                rawFooter = fuFooter.pack(footer);


                footer.checksum = checksumStruct(rawFooter, fuFooter.fields.checksum);
                debug('Write footer at: ' + offset + ' (checksum=' + footer.checksum + '). (data=' + rawFooter.toString('hex') + ')');

                _context11.next = 7;
                return this._write(rawFooter, 0);

              case 7:
                _context11.next = 9;
                return this._write(rawFooter, offset);

              case 9:
              case 'end':
                return _context11.stop();
            }
          }
        }, _callee11, this);
      }));

      function writeFooter() {
        return _ref11.apply(this, arguments);
      }

      return writeFooter;
    }()
  }, {
    key: 'writeHeader',
    value: function () {
      var _ref12 = (0, _asyncToGenerator3.default)(_regenerator2.default.mark(function _callee12() {
        var header, rawHeader, offset;
        return _regenerator2.default.wrap(function _callee12$(_context12) {
          while (1) {
            switch (_context12.prev = _context12.next) {
              case 0:
                header = this.header;
                rawHeader = fuHeader.pack(header);

                header.checksum = checksumStruct(rawHeader, fuHeader.fields.checksum);
                offset = VHD_FOOTER_SIZE;

                debug('Write header at: ' + offset + ' (checksum=' + header.checksum + '). (data=' + rawHeader.toString('hex') + ')');
                _context12.next = 7;
                return this._write(rawHeader, offset);

              case 7:
              case 'end':
                return _context12.stop();
            }
          }
        }, _callee12, this);
      }));

      function writeHeader() {
        return _ref12.apply(this, arguments);
      }

      return writeHeader;
    }()
  }]);
  return Vhd;
}();
//# sourceMappingURL=vhd.js.map