ceph-csi/vendor/github.com/google/cel-go/ext/native.go

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// Copyright 2022 Google LLC
//
// 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 ext
import (
"fmt"
"reflect"
"strings"
"time"
"google.golang.org/protobuf/proto"
"google.golang.org/protobuf/reflect/protoreflect"
"github.com/google/cel-go/cel"
"github.com/google/cel-go/common/types"
"github.com/google/cel-go/common/types/pb"
"github.com/google/cel-go/common/types/ref"
"github.com/google/cel-go/common/types/traits"
structpb "google.golang.org/protobuf/types/known/structpb"
)
var (
nativeObjTraitMask = traits.FieldTesterType | traits.IndexerType
jsonValueType = reflect.TypeOf(&structpb.Value{})
jsonStructType = reflect.TypeOf(&structpb.Struct{})
)
// NativeTypes creates a type provider which uses reflect.Type and reflect.Value instances
// to produce type definitions that can be used within CEL.
//
// All struct types in Go are exposed to CEL via their simple package name and struct type name:
//
// ```go
// package identity
//
// type Account struct {
// ID int
// }
//
// ```
//
// The type `identity.Account` would be exported to CEL using the same qualified name, e.g.
// `identity.Account{ID: 1234}` would create a new `Account` instance with the `ID` field
// populated.
//
// Only exported fields are exposed via NativeTypes, and the type-mapping between Go and CEL
// is as follows:
//
// | Go type | CEL type |
// |-------------------------------------|-----------|
// | bool | bool |
// | []byte | bytes |
// | float32, float64 | double |
// | int, int8, int16, int32, int64 | int |
// | string | string |
// | uint, uint8, uint16, uint32, uint64 | uint |
// | time.Duration | duration |
// | time.Time | timestamp |
// | array, slice | list |
// | map | map |
//
// Please note, if you intend to configure support for proto messages in addition to native
// types, you will need to provide the protobuf types before the golang native types. The
// same advice holds if you are using custom type adapters and type providers. The native type
// provider composes over whichever type adapter and provider is configured in the cel.Env at
// the time that it is invoked.
func NativeTypes(refTypes ...any) cel.EnvOption {
return func(env *cel.Env) (*cel.Env, error) {
tp, err := newNativeTypeProvider(env.CELTypeAdapter(), env.CELTypeProvider(), refTypes...)
if err != nil {
return nil, err
}
env, err = cel.CustomTypeAdapter(tp)(env)
if err != nil {
return nil, err
}
return cel.CustomTypeProvider(tp)(env)
}
}
func newNativeTypeProvider(adapter types.Adapter, provider types.Provider, refTypes ...any) (*nativeTypeProvider, error) {
nativeTypes := make(map[string]*nativeType, len(refTypes))
for _, refType := range refTypes {
switch rt := refType.(type) {
case reflect.Type:
t, err := newNativeType(rt)
if err != nil {
return nil, err
}
nativeTypes[t.TypeName()] = t
case reflect.Value:
t, err := newNativeType(rt.Type())
if err != nil {
return nil, err
}
nativeTypes[t.TypeName()] = t
default:
return nil, fmt.Errorf("unsupported native type: %v (%T) must be reflect.Type or reflect.Value", rt, rt)
}
}
return &nativeTypeProvider{
nativeTypes: nativeTypes,
baseAdapter: adapter,
baseProvider: provider,
}, nil
}
type nativeTypeProvider struct {
nativeTypes map[string]*nativeType
baseAdapter types.Adapter
baseProvider types.Provider
}
// EnumValue proxies to the types.Provider configured at the times the NativeTypes
// option was configured.
func (tp *nativeTypeProvider) EnumValue(enumName string) ref.Val {
return tp.baseProvider.EnumValue(enumName)
}
// FindIdent looks up natives type instances by qualified identifier, and if not found
// proxies to the composed types.Provider.
func (tp *nativeTypeProvider) FindIdent(typeName string) (ref.Val, bool) {
if t, found := tp.nativeTypes[typeName]; found {
return t, true
}
return tp.baseProvider.FindIdent(typeName)
}
// FindStructType looks up the CEL type definition by qualified identifier, and if not found
// proxies to the composed types.Provider.
func (tp *nativeTypeProvider) FindStructType(typeName string) (*types.Type, bool) {
if _, found := tp.nativeTypes[typeName]; found {
return types.NewTypeTypeWithParam(types.NewObjectType(typeName)), true
}
if celType, found := tp.baseProvider.FindStructType(typeName); found {
return celType, true
}
return tp.baseProvider.FindStructType(typeName)
}
// FindStructFieldType looks up a native type's field definition, and if the type name is not a native
// type then proxies to the composed types.Provider
func (tp *nativeTypeProvider) FindStructFieldType(typeName, fieldName string) (*types.FieldType, bool) {
t, found := tp.nativeTypes[typeName]
if !found {
return tp.baseProvider.FindStructFieldType(typeName, fieldName)
}
refField, isDefined := t.hasField(fieldName)
if !found || !isDefined {
return nil, false
}
celType, ok := convertToCelType(refField.Type)
if !ok {
return nil, false
}
return &types.FieldType{
Type: celType,
IsSet: func(obj any) bool {
refVal := reflect.Indirect(reflect.ValueOf(obj))
refField := refVal.FieldByName(fieldName)
return !refField.IsZero()
},
GetFrom: func(obj any) (any, error) {
refVal := reflect.Indirect(reflect.ValueOf(obj))
refField := refVal.FieldByName(fieldName)
return getFieldValue(tp, refField), nil
},
}, true
}
// NewValue implements the ref.TypeProvider interface method.
func (tp *nativeTypeProvider) NewValue(typeName string, fields map[string]ref.Val) ref.Val {
t, found := tp.nativeTypes[typeName]
if !found {
return tp.baseProvider.NewValue(typeName, fields)
}
refPtr := reflect.New(t.refType)
refVal := refPtr.Elem()
for fieldName, val := range fields {
refFieldDef, isDefined := t.hasField(fieldName)
if !isDefined {
return types.NewErr("no such field: %s", fieldName)
}
fieldVal, err := val.ConvertToNative(refFieldDef.Type)
if err != nil {
return types.NewErr(err.Error())
}
refField := refVal.FieldByIndex(refFieldDef.Index)
refFieldVal := reflect.ValueOf(fieldVal)
refField.Set(refFieldVal)
}
return tp.NativeToValue(refPtr.Interface())
}
// NewValue adapts native values to CEL values and will proxy to the composed type adapter
// for non-native types.
func (tp *nativeTypeProvider) NativeToValue(val any) ref.Val {
if val == nil {
return types.NullValue
}
if v, ok := val.(ref.Val); ok {
return v
}
rawVal := reflect.ValueOf(val)
refVal := rawVal
if refVal.Kind() == reflect.Ptr {
refVal = reflect.Indirect(refVal)
}
// This isn't quite right if you're also supporting proto,
// but maybe an acceptable limitation.
switch refVal.Kind() {
case reflect.Array, reflect.Slice:
switch val := val.(type) {
case []byte:
return tp.baseAdapter.NativeToValue(val)
default:
return types.NewDynamicList(tp, val)
}
case reflect.Map:
return types.NewDynamicMap(tp, val)
case reflect.Struct:
switch val := val.(type) {
case proto.Message, *pb.Map, protoreflect.List, protoreflect.Message, protoreflect.Value,
time.Time:
return tp.baseAdapter.NativeToValue(val)
default:
return newNativeObject(tp, val, rawVal)
}
default:
return tp.baseAdapter.NativeToValue(val)
}
}
func convertToCelType(refType reflect.Type) (*cel.Type, bool) {
switch refType.Kind() {
case reflect.Bool:
return cel.BoolType, true
case reflect.Float32, reflect.Float64:
return cel.DoubleType, true
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
if refType == durationType {
return cel.DurationType, true
}
return cel.IntType, true
case reflect.String:
return cel.StringType, true
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
return cel.UintType, true
case reflect.Array, reflect.Slice:
refElem := refType.Elem()
if refElem == reflect.TypeOf(byte(0)) {
return cel.BytesType, true
}
elemType, ok := convertToCelType(refElem)
if !ok {
return nil, false
}
return cel.ListType(elemType), true
case reflect.Map:
keyType, ok := convertToCelType(refType.Key())
if !ok {
return nil, false
}
// Ensure the key type is a int, bool, uint, string
elemType, ok := convertToCelType(refType.Elem())
if !ok {
return nil, false
}
return cel.MapType(keyType, elemType), true
case reflect.Struct:
if refType == timestampType {
return cel.TimestampType, true
}
return cel.ObjectType(
fmt.Sprintf("%s.%s", simplePkgAlias(refType.PkgPath()), refType.Name()),
), true
case reflect.Pointer:
if refType.Implements(pbMsgInterfaceType) {
pbMsg := reflect.New(refType.Elem()).Interface().(protoreflect.ProtoMessage)
return cel.ObjectType(string(pbMsg.ProtoReflect().Descriptor().FullName())), true
}
return convertToCelType(refType.Elem())
}
return nil, false
}
func newNativeObject(adapter types.Adapter, val any, refValue reflect.Value) ref.Val {
valType, err := newNativeType(refValue.Type())
if err != nil {
return types.NewErr(err.Error())
}
return &nativeObj{
Adapter: adapter,
val: val,
valType: valType,
refValue: refValue,
}
}
type nativeObj struct {
types.Adapter
val any
valType *nativeType
refValue reflect.Value
}
// ConvertToNative implements the ref.Val interface method.
//
// CEL does not have a notion of pointers, so whether a field is a pointer or value
// is handled as part of this conversion step.
func (o *nativeObj) ConvertToNative(typeDesc reflect.Type) (any, error) {
if o.refValue.Type() == typeDesc {
return o.val, nil
}
if o.refValue.Kind() == reflect.Pointer && o.refValue.Type().Elem() == typeDesc {
return o.refValue.Elem().Interface(), nil
}
if typeDesc.Kind() == reflect.Pointer && o.refValue.Type() == typeDesc.Elem() {
ptr := reflect.New(typeDesc.Elem())
ptr.Elem().Set(o.refValue)
return ptr.Interface(), nil
}
switch typeDesc {
case jsonValueType:
jsonStruct, err := o.ConvertToNative(jsonStructType)
if err != nil {
return nil, err
}
return structpb.NewStructValue(jsonStruct.(*structpb.Struct)), nil
case jsonStructType:
refVal := reflect.Indirect(o.refValue)
refType := refVal.Type()
fields := make(map[string]*structpb.Value, refVal.NumField())
for i := 0; i < refVal.NumField(); i++ {
fieldType := refType.Field(i)
fieldValue := refVal.Field(i)
if !fieldValue.IsValid() || fieldValue.IsZero() {
continue
}
fieldCELVal := o.NativeToValue(fieldValue.Interface())
fieldJSONVal, err := fieldCELVal.ConvertToNative(jsonValueType)
if err != nil {
return nil, err
}
fields[fieldType.Name] = fieldJSONVal.(*structpb.Value)
}
return &structpb.Struct{Fields: fields}, nil
}
return nil, fmt.Errorf("type conversion error from '%v' to '%v'", o.Type(), typeDesc)
}
// ConvertToType implements the ref.Val interface method.
func (o *nativeObj) ConvertToType(typeVal ref.Type) ref.Val {
switch typeVal {
case types.TypeType:
return o.valType
default:
if typeVal.TypeName() == o.valType.typeName {
return o
}
}
return types.NewErr("type conversion error from '%s' to '%s'", o.Type(), typeVal)
}
// Equal implements the ref.Val interface method.
//
// Note, that in Golang a pointer to a value is not equal to the value it contains.
// In CEL pointers and values to which they point are equal.
func (o *nativeObj) Equal(other ref.Val) ref.Val {
otherNtv, ok := other.(*nativeObj)
if !ok {
return types.False
}
val := o.val
otherVal := otherNtv.val
refVal := o.refValue
otherRefVal := otherNtv.refValue
if refVal.Kind() != otherRefVal.Kind() {
if refVal.Kind() == reflect.Pointer {
val = refVal.Elem().Interface()
} else if otherRefVal.Kind() == reflect.Pointer {
otherVal = otherRefVal.Elem().Interface()
}
}
return types.Bool(reflect.DeepEqual(val, otherVal))
}
// IsZeroValue indicates whether the contained Golang value is a zero value.
//
// Golang largely follows proto3 semantics for zero values.
func (o *nativeObj) IsZeroValue() bool {
return reflect.Indirect(o.refValue).IsZero()
}
// IsSet tests whether a field which is defined is set to a non-default value.
func (o *nativeObj) IsSet(field ref.Val) ref.Val {
refField, refErr := o.getReflectedField(field)
if refErr != nil {
return refErr
}
return types.Bool(!refField.IsZero())
}
// Get returns the value fo a field name.
func (o *nativeObj) Get(field ref.Val) ref.Val {
refField, refErr := o.getReflectedField(field)
if refErr != nil {
return refErr
}
return adaptFieldValue(o, refField)
}
func (o *nativeObj) getReflectedField(field ref.Val) (reflect.Value, ref.Val) {
fieldName, ok := field.(types.String)
if !ok {
return reflect.Value{}, types.MaybeNoSuchOverloadErr(field)
}
fieldNameStr := string(fieldName)
refField, isDefined := o.valType.hasField(fieldNameStr)
if !isDefined {
return reflect.Value{}, types.NewErr("no such field: %s", fieldName)
}
refVal := reflect.Indirect(o.refValue)
return refVal.FieldByIndex(refField.Index), nil
}
// Type implements the ref.Val interface method.
func (o *nativeObj) Type() ref.Type {
return o.valType
}
// Value implements the ref.Val interface method.
func (o *nativeObj) Value() any {
return o.val
}
func newNativeType(rawType reflect.Type) (*nativeType, error) {
refType := rawType
if refType.Kind() == reflect.Pointer {
refType = refType.Elem()
}
if !isValidObjectType(refType) {
return nil, fmt.Errorf("unsupported reflect.Type %v, must be reflect.Struct", rawType)
}
return &nativeType{
typeName: fmt.Sprintf("%s.%s", simplePkgAlias(refType.PkgPath()), refType.Name()),
refType: refType,
}, nil
}
type nativeType struct {
typeName string
refType reflect.Type
}
// ConvertToNative implements ref.Val.ConvertToNative.
func (t *nativeType) ConvertToNative(typeDesc reflect.Type) (any, error) {
return nil, fmt.Errorf("type conversion error for type to '%v'", typeDesc)
}
// ConvertToType implements ref.Val.ConvertToType.
func (t *nativeType) ConvertToType(typeVal ref.Type) ref.Val {
switch typeVal {
case types.TypeType:
return types.TypeType
}
return types.NewErr("type conversion error from '%s' to '%s'", types.TypeType, typeVal)
}
// Equal returns true of both type names are equal to each other.
func (t *nativeType) Equal(other ref.Val) ref.Val {
otherType, ok := other.(ref.Type)
return types.Bool(ok && t.TypeName() == otherType.TypeName())
}
// HasTrait implements the ref.Type interface method.
func (t *nativeType) HasTrait(trait int) bool {
return nativeObjTraitMask&trait == trait
}
// String implements the strings.Stringer interface method.
func (t *nativeType) String() string {
return t.typeName
}
// Type implements the ref.Val interface method.
func (t *nativeType) Type() ref.Type {
return types.TypeType
}
// TypeName implements the ref.Type interface method.
func (t *nativeType) TypeName() string {
return t.typeName
}
// Value implements the ref.Val interface method.
func (t *nativeType) Value() any {
return t.typeName
}
// hasField returns whether a field name has a corresponding Golang reflect.StructField
func (t *nativeType) hasField(fieldName string) (reflect.StructField, bool) {
f, found := t.refType.FieldByName(fieldName)
if !found || !f.IsExported() || !isSupportedType(f.Type) {
return reflect.StructField{}, false
}
return f, true
}
func adaptFieldValue(adapter types.Adapter, refField reflect.Value) ref.Val {
return adapter.NativeToValue(getFieldValue(adapter, refField))
}
func getFieldValue(adapter types.Adapter, refField reflect.Value) any {
if refField.IsZero() {
switch refField.Kind() {
case reflect.Array, reflect.Slice:
return types.NewDynamicList(adapter, []ref.Val{})
case reflect.Map:
return types.NewDynamicMap(adapter, map[ref.Val]ref.Val{})
case reflect.Struct:
if refField.Type() == timestampType {
return types.Timestamp{Time: time.Unix(0, 0)}
}
return reflect.New(refField.Type()).Elem().Interface()
case reflect.Pointer:
return reflect.New(refField.Type().Elem()).Interface()
}
}
return refField.Interface()
}
func simplePkgAlias(pkgPath string) string {
paths := strings.Split(pkgPath, "/")
if len(paths) == 0 {
return ""
}
return paths[len(paths)-1]
}
func isValidObjectType(refType reflect.Type) bool {
return refType.Kind() == reflect.Struct
}
func isSupportedType(refType reflect.Type) bool {
switch refType.Kind() {
case reflect.Chan, reflect.Complex64, reflect.Complex128, reflect.Func, reflect.UnsafePointer, reflect.Uintptr:
return false
case reflect.Array, reflect.Slice:
return isSupportedType(refType.Elem())
case reflect.Map:
return isSupportedType(refType.Key()) && isSupportedType(refType.Elem())
}
return true
}
var (
pbMsgInterfaceType = reflect.TypeOf((*protoreflect.ProtoMessage)(nil)).Elem()
timestampType = reflect.TypeOf(time.Now())
durationType = reflect.TypeOf(time.Nanosecond)
)