Method AddVersion

db/hybrid_logical_vector.go:386–422

AddVersion adds newVersion as the current version to the in memory representation of the HLV.

(newVersion Version)

// AddVersion adds newVersion as the current version to the in memory representation of the HLV.
func (hlv *HybridLogicalVector) AddVersion(newVersion Version) error {

	// check if this is the first time we're adding a source - version pair
	if hlv.SourceID == "" {
		hlv.Version = newVersion.Value
		hlv.SourceID = newVersion.SourceID
		return nil
	}

	// If the new version is older than an existing version for the same source, return error
	existingValueForSource, found := hlv.GetValue(newVersion.SourceID)
	if found && existingValueForSource > newVersion.Value {
		return fmt.Errorf("attempting to add new version vector entry with a value that is less than the existing value for the same source. New version: %v, Existing HLV: %v", newVersion, hlv)
	}

	// Move existing mv to pv before adding the new version
	hlv.InvalidateMV()

	// If the new version has the same source as existing cv, we just update the cv value
	if newVersion.SourceID == hlv.SourceID {
		hlv.Version = newVersion.Value
		return nil
	}

	// If we get here this is a new version from a different sourceID.  Need to move existing cv to pv and update cv
	if hlv.PreviousVersions == nil {
		hlv.PreviousVersions = make(HLVVersions)
	}

	hlv.PreviousVersions[hlv.SourceID] = hlv.Version

	// If new version source already existed in PV, need to remove it
	delete(hlv.PreviousVersions, newVersion.SourceID)
	hlv.Version = newVersion.Value
	hlv.SourceID = newVersion.SourceID
	return nil
}

// InvalidateMV will move all merge versions to PV, except merge version entries that share a source with cv
func (hlv *HybridLogicalVector) InvalidateMV() {