pulumi/sdk/go/internal/rpc.go

66 lines
2.0 KiB
Go

// Copyright 2016-2023, Pulumi Corporation.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package internal
import (
"fmt"
"reflect"
"github.com/pulumi/pulumi/sdk/v3/go/common/util/contract"
)
// MapStructTypes returns a function that maps the fields of struct type 'from'
// to the fields of struct type 'to'.
//
// The returned function takes a value of type 'to'
// and an index of a field in 'from',
// and returns the corresponding field in 'to'.
// The value may be omitted if just the field's type information is needed.
func MapStructTypes(from, to reflect.Type) func(reflect.Value, int) (reflect.StructField, reflect.Value) {
contract.Assertf(from.Kind() == reflect.Struct, "from must be a struct type, got %v (%v)", from, from.Kind())
contract.Assertf(to.Kind() == reflect.Struct, "to must be a struct type, got %v (%v)", to, to.Kind())
if from == to {
return func(v reflect.Value, i int) (reflect.StructField, reflect.Value) {
var fv reflect.Value
if v.IsValid() {
fv = v.Field(i)
}
return to.Field(i), fv
}
}
nameToIndex := map[string]int{}
numFields := to.NumField()
for i := 0; i < numFields; i++ {
nameToIndex[to.Field(i).Name] = i
}
return func(v reflect.Value, i int) (reflect.StructField, reflect.Value) {
fieldName := from.Field(i).Name
j, ok := nameToIndex[fieldName]
if !ok {
panic(fmt.Errorf("unknown field %v when marshaling inputs of type %v to %v", fieldName, from, to))
}
field := to.Field(j)
var fieldValue reflect.Value
if v.IsValid() {
fieldValue = v.Field(j)
}
return field, fieldValue
}
}