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matterbridge/vendor/github.com/graph-gophers/graphql-go/internal/exec/packer/packer.go
2022-04-01 00:23:19 +02:00

391 lines
9.1 KiB
Go

package packer
import (
"fmt"
"math"
"reflect"
"strings"
"github.com/graph-gophers/graphql-go/decode"
"github.com/graph-gophers/graphql-go/errors"
"github.com/graph-gophers/graphql-go/types"
)
type packer interface {
Pack(value interface{}) (reflect.Value, error)
}
type Builder struct {
packerMap map[typePair]*packerMapEntry
structPackers []*StructPacker
}
type typePair struct {
graphQLType types.Type
resolverType reflect.Type
}
type packerMapEntry struct {
packer packer
targets []*packer
}
func NewBuilder() *Builder {
return &Builder{
packerMap: make(map[typePair]*packerMapEntry),
}
}
func (b *Builder) Finish() error {
for _, entry := range b.packerMap {
for _, target := range entry.targets {
*target = entry.packer
}
}
for _, p := range b.structPackers {
p.defaultStruct = reflect.New(p.structType).Elem()
for _, f := range p.fields {
if defaultVal := f.field.Default; defaultVal != nil {
v, err := f.fieldPacker.Pack(defaultVal.Deserialize(nil))
if err != nil {
return err
}
p.defaultStruct.FieldByIndex(f.fieldIndex).Set(v)
}
}
}
return nil
}
func (b *Builder) assignPacker(target *packer, schemaType types.Type, reflectType reflect.Type) error {
k := typePair{schemaType, reflectType}
ref, ok := b.packerMap[k]
if !ok {
ref = &packerMapEntry{}
b.packerMap[k] = ref
var err error
ref.packer, err = b.makePacker(schemaType, reflectType)
if err != nil {
return err
}
}
ref.targets = append(ref.targets, target)
return nil
}
func (b *Builder) makePacker(schemaType types.Type, reflectType reflect.Type) (packer, error) {
t, nonNull := unwrapNonNull(schemaType)
if !nonNull {
if reflectType.Kind() == reflect.Ptr {
elemType := reflectType.Elem()
addPtr := true
if _, ok := t.(*types.InputObject); ok {
elemType = reflectType // keep pointer for input objects
addPtr = false
}
elem, err := b.makeNonNullPacker(t, elemType)
if err != nil {
return nil, err
}
return &nullPacker{
elemPacker: elem,
valueType: reflectType,
addPtr: addPtr,
}, nil
} else if isNullable(reflectType) {
elemType := reflectType
addPtr := false
elem, err := b.makeNonNullPacker(t, elemType)
if err != nil {
return nil, err
}
return &nullPacker{
elemPacker: elem,
valueType: reflectType,
addPtr: addPtr,
}, nil
} else {
return nil, fmt.Errorf("%s is not a pointer or a nullable type", reflectType)
}
}
return b.makeNonNullPacker(t, reflectType)
}
func (b *Builder) makeNonNullPacker(schemaType types.Type, reflectType reflect.Type) (packer, error) {
if u, ok := reflect.New(reflectType).Interface().(decode.Unmarshaler); ok {
if !u.ImplementsGraphQLType(schemaType.String()) {
return nil, fmt.Errorf("can not unmarshal %s into %s", schemaType, reflectType)
}
return &unmarshalerPacker{
ValueType: reflectType,
}, nil
}
switch t := schemaType.(type) {
case *types.ScalarTypeDefinition:
return &ValuePacker{
ValueType: reflectType,
}, nil
case *types.EnumTypeDefinition:
if reflectType.Kind() != reflect.String {
return nil, fmt.Errorf("wrong type, expected %s", reflect.String)
}
return &ValuePacker{
ValueType: reflectType,
}, nil
case *types.InputObject:
e, err := b.MakeStructPacker(t.Values, reflectType)
if err != nil {
return nil, err
}
return e, nil
case *types.List:
if reflectType.Kind() != reflect.Slice {
return nil, fmt.Errorf("expected slice, got %s", reflectType)
}
p := &listPacker{
sliceType: reflectType,
}
if err := b.assignPacker(&p.elem, t.OfType, reflectType.Elem()); err != nil {
return nil, err
}
return p, nil
case *types.ObjectTypeDefinition, *types.InterfaceTypeDefinition, *types.Union:
return nil, fmt.Errorf("type of kind %s can not be used as input", t.Kind())
default:
panic("unreachable")
}
}
func (b *Builder) MakeStructPacker(values []*types.InputValueDefinition, typ reflect.Type) (*StructPacker, error) {
structType := typ
usePtr := false
if typ.Kind() == reflect.Ptr {
structType = typ.Elem()
usePtr = true
}
if structType.Kind() != reflect.Struct {
return nil, fmt.Errorf("expected struct or pointer to struct, got %s (hint: missing `args struct { ... }` wrapper for field arguments?)", typ)
}
var fields []*structPackerField
for _, v := range values {
fe := &structPackerField{field: v}
fx := func(n string) bool {
return strings.EqualFold(stripUnderscore(n), stripUnderscore(v.Name.Name))
}
sf, ok := structType.FieldByNameFunc(fx)
if !ok {
return nil, fmt.Errorf("%s does not define field %q (hint: missing `args struct { ... }` wrapper for field arguments, or missing field on input struct)", typ, v.Name.Name)
}
if sf.PkgPath != "" {
return nil, fmt.Errorf("field %q must be exported", sf.Name)
}
fe.fieldIndex = sf.Index
ft := v.Type
if v.Default != nil {
ft, _ = unwrapNonNull(ft)
ft = &types.NonNull{OfType: ft}
}
if err := b.assignPacker(&fe.fieldPacker, ft, sf.Type); err != nil {
return nil, fmt.Errorf("field %q: %s", sf.Name, err)
}
fields = append(fields, fe)
}
p := &StructPacker{
structType: structType,
usePtr: usePtr,
fields: fields,
}
b.structPackers = append(b.structPackers, p)
return p, nil
}
type StructPacker struct {
structType reflect.Type
usePtr bool
defaultStruct reflect.Value
fields []*structPackerField
}
type structPackerField struct {
field *types.InputValueDefinition
fieldIndex []int
fieldPacker packer
}
func (p *StructPacker) Pack(value interface{}) (reflect.Value, error) {
if value == nil {
return reflect.Value{}, errors.Errorf("got null for non-null")
}
values := value.(map[string]interface{})
v := reflect.New(p.structType)
v.Elem().Set(p.defaultStruct)
for _, f := range p.fields {
if value, ok := values[f.field.Name.Name]; ok {
packed, err := f.fieldPacker.Pack(value)
if err != nil {
return reflect.Value{}, err
}
v.Elem().FieldByIndex(f.fieldIndex).Set(packed)
}
}
if !p.usePtr {
return v.Elem(), nil
}
return v, nil
}
type listPacker struct {
sliceType reflect.Type
elem packer
}
func (e *listPacker) Pack(value interface{}) (reflect.Value, error) {
list, ok := value.([]interface{})
if !ok {
list = []interface{}{value}
}
v := reflect.MakeSlice(e.sliceType, len(list), len(list))
for i := range list {
packed, err := e.elem.Pack(list[i])
if err != nil {
return reflect.Value{}, err
}
v.Index(i).Set(packed)
}
return v, nil
}
type nullPacker struct {
elemPacker packer
valueType reflect.Type
addPtr bool
}
func (p *nullPacker) Pack(value interface{}) (reflect.Value, error) {
if value == nil && !isNullable(p.valueType) {
return reflect.Zero(p.valueType), nil
}
v, err := p.elemPacker.Pack(value)
if err != nil {
return reflect.Value{}, err
}
if p.addPtr {
ptr := reflect.New(p.valueType.Elem())
ptr.Elem().Set(v)
return ptr, nil
}
return v, nil
}
type ValuePacker struct {
ValueType reflect.Type
}
func (p *ValuePacker) Pack(value interface{}) (reflect.Value, error) {
if value == nil {
return reflect.Value{}, errors.Errorf("got null for non-null")
}
coerced, err := unmarshalInput(p.ValueType, value)
if err != nil {
return reflect.Value{}, fmt.Errorf("could not unmarshal %#v (%T) into %s: %s", value, value, p.ValueType, err)
}
return reflect.ValueOf(coerced), nil
}
type unmarshalerPacker struct {
ValueType reflect.Type
}
func (p *unmarshalerPacker) Pack(value interface{}) (reflect.Value, error) {
if value == nil && !isNullable(p.ValueType) {
return reflect.Value{}, errors.Errorf("got null for non-null")
}
v := reflect.New(p.ValueType)
if err := v.Interface().(decode.Unmarshaler).UnmarshalGraphQL(value); err != nil {
return reflect.Value{}, err
}
return v.Elem(), nil
}
func unmarshalInput(typ reflect.Type, input interface{}) (interface{}, error) {
if reflect.TypeOf(input) == typ {
return input, nil
}
switch typ.Kind() {
case reflect.Int32:
switch input := input.(type) {
case int:
if input < math.MinInt32 || input > math.MaxInt32 {
return nil, fmt.Errorf("not a 32-bit integer")
}
return int32(input), nil
case float64:
coerced := int32(input)
if input < math.MinInt32 || input > math.MaxInt32 || float64(coerced) != input {
return nil, fmt.Errorf("not a 32-bit integer")
}
return coerced, nil
}
case reflect.Float64:
switch input := input.(type) {
case int32:
return float64(input), nil
case int:
return float64(input), nil
}
case reflect.String:
if reflect.TypeOf(input).ConvertibleTo(typ) {
return reflect.ValueOf(input).Convert(typ).Interface(), nil
}
}
return nil, fmt.Errorf("incompatible type")
}
func unwrapNonNull(t types.Type) (types.Type, bool) {
if nn, ok := t.(*types.NonNull); ok {
return nn.OfType, true
}
return t, false
}
func stripUnderscore(s string) string {
return strings.Replace(s, "_", "", -1)
}
// NullUnmarshaller is an unmarshaller that can handle a nil input
type NullUnmarshaller interface {
decode.Unmarshaler
Nullable()
}
func isNullable(t reflect.Type) bool {
_, ok := reflect.New(t).Interface().(NullUnmarshaller)
return ok
}