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DatabaseRoot.coffee 

CompressedUnsignedLongByteIterable =
  (require '../log/iterate/CompressedUnsignedLongByteIterable.coffee').
  CompressedUnsignedLongByteIterable
DataIterator = (require '../log/DataIterator.coffee').DataIterator
LightReadIterator = (require '../log/DataIterator.coffee').LightReadIterator
LoggableToWrite = (require '../log/LoggableToWrite.coffee').LoggableToWrite
RandomAccessLoggable =
  (require '../log/RandomAccessLoggable.coffee').RandomAccessLoggable
LightOutputStream =
  (require '../database/impl/iterate/LightOutputStream.coffee').
  LightOutputStream
Addr64 = (require '../log/Addr64.coffee').Addr64

This class is necessary for commmiting log. It is written in log before each commit and contains kind of check sum. If it is valid, everything was written correctly.

 
class DatabaseRoot extends RandomAccessLoggable
  @DATABASE_ROOT_TYPE: 1
  @MAGIC_DIFF: 199

@private

 
  rootAddress: undefined

@private

 
  lastStructureId: undefined

@private

 
  isValid: undefined

Constructor takes rootAddress and lastStructureId.

 
  @create$Addr64$int: (rootAddress, lastStructureId, o) ->
    if !o? then o = new DatabaseRoot()
    o.rootAddress = rootAddress
    o.lastStructureId = lastStructureId
    o.isValid = undefined
    return o

  getRootAddress: () ->
    return @rootAddress

  getLastStructureId: () ->
    return @lastStructureId

  isValid: () ->
    return @isValid

Get WriteLogable that can be written to log.

 
  toLoggable: () ->
    dataLength =
      CompressedUnsignedLongByteIterable.
      getCompressedSize$int(@rootAddress.toFloat()) +
      CompressedUnsignedLongByteIterable.
      getCompressedSize$int(@lastStructureId) +
      CompressedUnsignedLongByteIterable.
      getCompressedSize$int(@rootAddress.toFloat() + @lastStructureId +
      DatabaseRoot.MAGIC_DIFF)
    los = LightOutputStream.create$int dataLength
    CompressedUnsignedLongByteIterable.
    fillBytes$int$LightOutputStream @rootAddress.toFloat(), los
    CompressedUnsignedLongByteIterable.
    fillBytes$int$LightOutputStream @lastStructureId, los
    CompressedUnsignedLongByteIterable.
    fillBytes$int$LightOutputStream @rootAddress.toFloat() +
    @lastStructureId + DatabaseRoot.MAGIC_DIFF, los
    return LoggableToWrite.
    create$int$ByteIterable$int DatabaseRoot.DATABASE_ROOT_TYPE,
            los.asArrayByteIterable()

Temporary function, until I undestand Loggable factories and usage of static temp emitters. Very DANGEROUS and should be rewritten anyway!!!

 
  readFromLoggable: (loggable) ->
    it = loggable.getData().iterator()
    nums = new Object()
    emit = false
    onGetAllNumbers = () =>
      @rootAddressInt = nums[1]
      @rootAddress = Addr64.create$int$int(0, 0).plus$int(@rootAddressInt)
      @lastStructureId = nums[2]
      @isValid = @rootAddressInt == nums[3] -
      @lastStructureId - DatabaseRoot.MAGIC_DIFF
      if emit
        @emit 'readFromLoggable', @isValid
    k = 0
    CompressedUnsignedLongByteIterable.EMITTER.once 'getInt', (value) =>
      nums[k] = value
      if k != 3
        for i in [k + 1..3]
          nums[i] = CompressedUnsignedLongByteIterable.
          getInt$ByteIterator$emit it
      onGetAllNumbers()
    while k != 3
      k += 1
      nums[k] = CompressedUnsignedLongByteIterable.
      getInt$ByteIterator$emit it
      if !nums[k]?
        emit = true
        return undefined
    CompressedUnsignedLongByteIterable.EMITTER.removeAllListeners 'getInt'
    onGetAllNumbers()
    return @isValid

exports.DatabaseRoot = DatabaseRoot