upstream-corteza/server/federation/service/mapper.go

package service

import (
	ct "github.com/cortezaproject/corteza/server/compose/types"
	"github.com/cortezaproject/corteza/server/federation/types"
)

type (
	Mapper struct{}
)

// Merge copies the values from originating structure
// do the destination
//
// mostly, there will be less mapped fields on the destination
// side, so start looping from here
func (m *Mapper) Merge(in *ct.RecordValueSet, out *ct.RecordValueSet, mappings *types.ModuleFieldMappingSet) {
	var match *types.ModuleFieldMapping

	for _, destVal := range *out {
		// preset the value, since we're working with
		// a pointer to an existing structure, could be some leftovers
		destVal.Value = ""

		// find origin field
		if match, _ = mappings.FindByName(destVal.Name, types.ModuleFieldMappingSetFindTypeDestination); match == nil {
			continue
		}

		// use the found origin, so the mapping is correct
		for _, origVal := range *in {
			if origVal.Name == match.Origin.Name {
				destVal.Value = origVal.Value
				break
			}
		}
	}

	return
}

// Prepare creates a set of Records to be used later
// when the fields will be mapped via Merge()
func (m *Mapper) Prepare(mappings types.ModuleFieldMappingSet) (out ct.RecordValueSet) {
	for _, mm := range mappings {
		rv := &ct.RecordValue{
			Name:  mm.Destination.Name,
			Value: "",
		}
		out = append(out, rv)
	}

	return
}