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

vendor/github.com/google/cel-go/ext/encoders.go

@@ -0,0 +1,104 @@
+// Copyright 2020 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 (
+	"encoding/base64"
+
+	"github.com/google/cel-go/cel"
+	"github.com/google/cel-go/checker/decls"
+	"github.com/google/cel-go/interpreter/functions"
+
+	exprpb "google.golang.org/genproto/googleapis/api/expr/v1alpha1"
+)
+
+// Encoders returns a cel.EnvOption to configure extended functions for string, byte, and object
+// encodings.
+//
+// Base64.Decode
+//
+// Decodes base64-encoded string to bytes.
+//
+// This function will return an error if the string input is not base64-encoded.
+//
+//     base64.decode(<string>) -> <bytes>
+//
+// Examples:
+//
+//     base64.decode('aGVsbG8=')  // return b'hello'
+//     base64.decode('aGVsbG8')   // error
+//
+// Base64.Encode
+//
+// Encodes bytes to a base64-encoded string.
+//
+//     base64.encode(<bytes>)  -> <string>
+//
+// Examples:
+//
+//     base64.encode(b'hello') // return b'aGVsbG8='
+func Encoders() cel.EnvOption {
+	return cel.Lib(encoderLib{})
+}
+
+type encoderLib struct{}
+
+func (encoderLib) CompileOptions() []cel.EnvOption {
+	return []cel.EnvOption{
+		cel.Declarations(
+			decls.NewFunction("base64.decode",
+				decls.NewOverload("base64_decode_string",
+					[]*exprpb.Type{decls.String},
+					decls.Bytes)),
+			decls.NewFunction("base64.encode",
+				decls.NewOverload("base64_encode_bytes",
+					[]*exprpb.Type{decls.Bytes},
+					decls.String)),
+		),
+	}
+}
+
+func (encoderLib) ProgramOptions() []cel.ProgramOption {
+	wrappedBase64EncodeBytes := callInBytesOutString(base64EncodeBytes)
+	wrappedBase64DecodeString := callInStrOutBytes(base64DecodeString)
+	return []cel.ProgramOption{
+		cel.Functions(
+			&functions.Overload{
+				Operator: "base64.decode",
+				Unary:    wrappedBase64DecodeString,
+			},
+			&functions.Overload{
+				Operator: "base64_decode_string",
+				Unary:    wrappedBase64DecodeString,
+			},
+			&functions.Overload{
+				Operator: "base64.encode",
+				Unary:    wrappedBase64EncodeBytes,
+			},
+			&functions.Overload{
+				Operator: "base64_encode_bytes",
+				Unary:    wrappedBase64EncodeBytes,
+			},
+		),
+	}
+}
+
+func base64DecodeString(str string) ([]byte, error) {
+	return base64.StdEncoding.DecodeString(str)
+}
+
+func base64EncodeBytes(bytes []byte) (string, error) {
+	return base64.StdEncoding.EncodeToString(bytes), nil
+}