ceph-csi/vendor/github.com/google/cel-go/common/ast/ast.go

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// Copyright 2023 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 ast declares data structures useful for parsed and checked abstract syntax trees
package ast
import (
"fmt"
"github.com/google/cel-go/common/types"
"github.com/google/cel-go/common/types/ref"
structpb "google.golang.org/protobuf/types/known/structpb"
exprpb "google.golang.org/genproto/googleapis/api/expr/v1alpha1"
)
// CheckedAST contains a protobuf expression and source info along with CEL-native type and reference information.
type CheckedAST struct {
Expr *exprpb.Expr
SourceInfo *exprpb.SourceInfo
TypeMap map[int64]*types.Type
ReferenceMap map[int64]*ReferenceInfo
}
// CheckedASTToCheckedExpr converts a CheckedAST to a CheckedExpr protobouf.
func CheckedASTToCheckedExpr(ast *CheckedAST) (*exprpb.CheckedExpr, error) {
refMap := make(map[int64]*exprpb.Reference, len(ast.ReferenceMap))
for id, ref := range ast.ReferenceMap {
r, err := ReferenceInfoToReferenceExpr(ref)
if err != nil {
return nil, err
}
refMap[id] = r
}
typeMap := make(map[int64]*exprpb.Type, len(ast.TypeMap))
for id, typ := range ast.TypeMap {
t, err := types.TypeToExprType(typ)
if err != nil {
return nil, err
}
typeMap[id] = t
}
return &exprpb.CheckedExpr{
Expr: ast.Expr,
SourceInfo: ast.SourceInfo,
ReferenceMap: refMap,
TypeMap: typeMap,
}, nil
}
// CheckedExprToCheckedAST converts a CheckedExpr protobuf to a CheckedAST instance.
func CheckedExprToCheckedAST(checked *exprpb.CheckedExpr) (*CheckedAST, error) {
refMap := make(map[int64]*ReferenceInfo, len(checked.GetReferenceMap()))
for id, ref := range checked.GetReferenceMap() {
r, err := ReferenceExprToReferenceInfo(ref)
if err != nil {
return nil, err
}
refMap[id] = r
}
typeMap := make(map[int64]*types.Type, len(checked.GetTypeMap()))
for id, typ := range checked.GetTypeMap() {
t, err := types.ExprTypeToType(typ)
if err != nil {
return nil, err
}
typeMap[id] = t
}
return &CheckedAST{
Expr: checked.GetExpr(),
SourceInfo: checked.GetSourceInfo(),
ReferenceMap: refMap,
TypeMap: typeMap,
}, nil
}
// ReferenceInfo contains a CEL native representation of an identifier reference which may refer to
// either a qualified identifier name, a set of overload ids, or a constant value from an enum.
type ReferenceInfo struct {
Name string
OverloadIDs []string
Value ref.Val
}
// NewIdentReference creates a ReferenceInfo instance for an identifier with an optional constant value.
func NewIdentReference(name string, value ref.Val) *ReferenceInfo {
return &ReferenceInfo{Name: name, Value: value}
}
// NewFunctionReference creates a ReferenceInfo instance for a set of function overloads.
func NewFunctionReference(overloads ...string) *ReferenceInfo {
info := &ReferenceInfo{}
for _, id := range overloads {
info.AddOverload(id)
}
return info
}
// AddOverload appends a function overload ID to the ReferenceInfo.
func (r *ReferenceInfo) AddOverload(overloadID string) {
for _, id := range r.OverloadIDs {
if id == overloadID {
return
}
}
r.OverloadIDs = append(r.OverloadIDs, overloadID)
}
// Equals returns whether two references are identical to each other.
func (r *ReferenceInfo) Equals(other *ReferenceInfo) bool {
if r.Name != other.Name {
return false
}
if len(r.OverloadIDs) != len(other.OverloadIDs) {
return false
}
if len(r.OverloadIDs) != 0 {
overloadMap := make(map[string]struct{}, len(r.OverloadIDs))
for _, id := range r.OverloadIDs {
overloadMap[id] = struct{}{}
}
for _, id := range other.OverloadIDs {
_, found := overloadMap[id]
if !found {
return false
}
}
}
if r.Value == nil && other.Value == nil {
return true
}
if r.Value == nil && other.Value != nil ||
r.Value != nil && other.Value == nil ||
r.Value.Equal(other.Value) != types.True {
return false
}
return true
}
// ReferenceInfoToReferenceExpr converts a ReferenceInfo instance to a protobuf Reference suitable for serialization.
func ReferenceInfoToReferenceExpr(info *ReferenceInfo) (*exprpb.Reference, error) {
c, err := ValToConstant(info.Value)
if err != nil {
return nil, err
}
return &exprpb.Reference{
Name: info.Name,
OverloadId: info.OverloadIDs,
Value: c,
}, nil
}
// ReferenceExprToReferenceInfo converts a protobuf Reference into a CEL-native ReferenceInfo instance.
func ReferenceExprToReferenceInfo(ref *exprpb.Reference) (*ReferenceInfo, error) {
v, err := ConstantToVal(ref.GetValue())
if err != nil {
return nil, err
}
return &ReferenceInfo{
Name: ref.GetName(),
OverloadIDs: ref.GetOverloadId(),
Value: v,
}, nil
}
// ValToConstant converts a CEL-native ref.Val to a protobuf Constant.
//
// Only simple scalar types are supported by this method.
func ValToConstant(v ref.Val) (*exprpb.Constant, error) {
if v == nil {
return nil, nil
}
switch v.Type() {
case types.BoolType:
return &exprpb.Constant{ConstantKind: &exprpb.Constant_BoolValue{BoolValue: v.Value().(bool)}}, nil
case types.BytesType:
return &exprpb.Constant{ConstantKind: &exprpb.Constant_BytesValue{BytesValue: v.Value().([]byte)}}, nil
case types.DoubleType:
return &exprpb.Constant{ConstantKind: &exprpb.Constant_DoubleValue{DoubleValue: v.Value().(float64)}}, nil
case types.IntType:
return &exprpb.Constant{ConstantKind: &exprpb.Constant_Int64Value{Int64Value: v.Value().(int64)}}, nil
case types.NullType:
return &exprpb.Constant{ConstantKind: &exprpb.Constant_NullValue{NullValue: structpb.NullValue_NULL_VALUE}}, nil
case types.StringType:
return &exprpb.Constant{ConstantKind: &exprpb.Constant_StringValue{StringValue: v.Value().(string)}}, nil
case types.UintType:
return &exprpb.Constant{ConstantKind: &exprpb.Constant_Uint64Value{Uint64Value: v.Value().(uint64)}}, nil
}
return nil, fmt.Errorf("unsupported constant kind: %v", v.Type())
}
// ConstantToVal converts a protobuf Constant to a CEL-native ref.Val.
func ConstantToVal(c *exprpb.Constant) (ref.Val, error) {
if c == nil {
return nil, nil
}
switch c.GetConstantKind().(type) {
case *exprpb.Constant_BoolValue:
return types.Bool(c.GetBoolValue()), nil
case *exprpb.Constant_BytesValue:
return types.Bytes(c.GetBytesValue()), nil
case *exprpb.Constant_DoubleValue:
return types.Double(c.GetDoubleValue()), nil
case *exprpb.Constant_Int64Value:
return types.Int(c.GetInt64Value()), nil
case *exprpb.Constant_NullValue:
return types.NullValue, nil
case *exprpb.Constant_StringValue:
return types.String(c.GetStringValue()), nil
case *exprpb.Constant_Uint64Value:
return types.Uint(c.GetUint64Value()), nil
}
return nil, fmt.Errorf("unsupported constant kind: %v", c.GetConstantKind())
}