delta-history

Keeps version history of file buffers for getting the vcdiff delta between a version and the latest

API

createDeltaHistory([options])

• options Object
  • deltaToFileRatio Number
  • maxDiscSize Number
  • storageDirectory String

Returns an instance of DeltaHistory.

options.deltaToFileRatio = 10 (NOT IMPLEMENTED, only stores files)

Range: all integers > 0

Ratio of delta intermediaries to full files. Increasing this will reduce storage size at the cost of more CPU calculation.

options.maxDiscStorageSize = 128000000 (128 MB) (NOT IMPLEMENTED)

Range: all integers > 0

Maximum size in bytes to store recent file versions on disc. If this is reached, it will start deleting earlier files. If a single file is too large to fit, DeltaHistory.OversizedFileError will be thrown.

options.storageDirectory (NOT IMPLEMENTED)

Directory that stores persistant file version data. If this is not specified, the version store will be cleared when the package starts again.

Class: DeltaHistory

deltaHistory.addVersion(fileId, [file])

fileId String file Buffer = new Buffer([])

Returns String versionIdthat identifies the version for this particular file.

deltaHistory.hasFile(fileId)

fileId String

Returns true if there is at least one version for the given file, otherwise false.

deltaHistory.hasVersion(fileId, versionId)

fileId String versionId String

Returns true if the given version exists for the given file, otherwise false.

deltaHistory.getDelta(fileId, versionId)

fileId String versionId String

Returns Buffer vcdiff encoded delta with from the version given by versionId to the last file added. If the version isn't in storage (either never added or it was evicted), it returns null.

deltaHistory.getLastestVersion(fileId)

fileId String Returns Buffer of last file added to the file history given by fileId. If there was no last version, it returns null.

deltaHistory.reset()

Deletes all stored files.