Pin new dependency: github.com/google/cel-go v0.9.0

vendor/github.com/google/cel-go/cel/io.go

@@ -0,0 +1,122 @@
+// Copyright 2019 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 cel
+
+import (
+	"fmt"
+
+	"github.com/google/cel-go/common"
+	"github.com/google/cel-go/parser"
+
+	exprpb "google.golang.org/genproto/googleapis/api/expr/v1alpha1"
+)
+
+// CheckedExprToAst converts a checked expression proto message to an Ast.
+func CheckedExprToAst(checkedExpr *exprpb.CheckedExpr) *Ast {
+	return CheckedExprToAstWithSource(checkedExpr, nil)
+}
+
+// CheckedExprToAstWithSource converts a checked expression proto message to an Ast,
+// using the provided Source as the textual contents.
+//
+// In general the source is not necessary unless the AST has been modified between the
+// `Parse` and `Check` calls as an `Ast` created from the `Parse` step will carry the source
+// through future calls.
+//
+// Prefer CheckedExprToAst if loading expressions from storage.
+func CheckedExprToAstWithSource(checkedExpr *exprpb.CheckedExpr, src common.Source) *Ast {
+	refMap := checkedExpr.GetReferenceMap()
+	if refMap == nil {
+		refMap = map[int64]*exprpb.Reference{}
+	}
+	typeMap := checkedExpr.GetTypeMap()
+	if typeMap == nil {
+		typeMap = map[int64]*exprpb.Type{}
+	}
+	si := checkedExpr.GetSourceInfo()
+	if si == nil {
+		si = &exprpb.SourceInfo{}
+	}
+	if src == nil {
+		src = common.NewInfoSource(si)
+	}
+	return &Ast{
+		expr:    checkedExpr.GetExpr(),
+		info:    si,
+		source:  src,
+		refMap:  refMap,
+		typeMap: typeMap,
+	}
+}
+
+// AstToCheckedExpr converts an Ast to an protobuf CheckedExpr value.
+//
+// If the Ast.IsChecked() returns false, this conversion method will return an error.
+func AstToCheckedExpr(a *Ast) (*exprpb.CheckedExpr, error) {
+	if !a.IsChecked() {
+		return nil, fmt.Errorf("cannot convert unchecked ast")
+	}
+	return &exprpb.CheckedExpr{
+		Expr:         a.Expr(),
+		SourceInfo:   a.SourceInfo(),
+		ReferenceMap: a.refMap,
+		TypeMap:      a.typeMap,
+	}, nil
+}
+
+// ParsedExprToAst converts a parsed expression proto message to an Ast.
+func ParsedExprToAst(parsedExpr *exprpb.ParsedExpr) *Ast {
+	return ParsedExprToAstWithSource(parsedExpr, nil)
+}
+
+// ParsedExprToAstWithSource converts a parsed expression proto message to an Ast,
+// using the provided Source as the textual contents.
+//
+// In general you only need this if you need to recheck a previously checked
+// expression, or if you need to separately check a subset of an expression.
+//
+// Prefer ParsedExprToAst if loading expressions from storage.
+func ParsedExprToAstWithSource(parsedExpr *exprpb.ParsedExpr, src common.Source) *Ast {
+	si := parsedExpr.GetSourceInfo()
+	if si == nil {
+		si = &exprpb.SourceInfo{}
+	}
+	if src == nil {
+		src = common.NewInfoSource(si)
+	}
+	return &Ast{
+		expr:   parsedExpr.GetExpr(),
+		info:   si,
+		source: src,
+	}
+}
+
+// AstToParsedExpr converts an Ast to an protobuf ParsedExpr value.
+func AstToParsedExpr(a *Ast) (*exprpb.ParsedExpr, error) {
+	return &exprpb.ParsedExpr{
+		Expr:       a.Expr(),
+		SourceInfo: a.SourceInfo(),
+	}, nil
+}
+
+// AstToString converts an Ast back to a string if possible.
+//
+// Note, the conversion may not be an exact replica of the original expression, but will produce
+// a string that is semantically equivalent and whose textual representation is stable.
+func AstToString(a *Ast) (string, error) {
+	expr := a.Expr()
+	info := a.SourceInfo()
+	return parser.Unparse(expr, info)
+}