Move ref.Val -> api.expr.Value converter to io.go (google#480)

Move ref.value <-> api.expr.Value converters to io.go

This allows users of the go CEL library to consume this code. This
change also adds a round tripping test case for the converters

cel/BUILD.bazel

@@ -24,23 +24,29 @@ go_library(
         "//common/types:go_default_library",
         "//common/types/pb:go_default_library",
         "//common/types/ref:go_default_library",
+        "//common/types/traits:go_default_library",
         "//interpreter:go_default_library",
         "//interpreter/functions:go_default_library",
         "//parser:go_default_library",
+        "//test/proto3pb:go_default_library",
         "@org_golang_google_genproto//googleapis/api/expr/v1alpha1:go_default_library",
         "@org_golang_google_protobuf//proto:go_default_library",
         "@org_golang_google_protobuf//reflect/protodesc:go_default_library",
         "@org_golang_google_protobuf//reflect/protoreflect:go_default_library",
         "@org_golang_google_protobuf//reflect/protoregistry:go_default_library",
         "@org_golang_google_protobuf//types/descriptorpb:go_default_library",
         "@org_golang_google_protobuf//types/dynamicpb:go_default_library",
+        "@org_golang_google_protobuf//types/known/anypb:go_default_library",
+        "@org_golang_google_protobuf//types/known/durationpb:go_default_library",
+        "@org_golang_google_protobuf//types/known/timestamppb:go_default_library",
     ],
 )
 
 go_test(
     name = "go_default_test",
     srcs = [
         "cel_test.go",
+        "io_test.go",
     ],
     data = [
         "//cel/testdata:gen_test_fds",
@@ -60,5 +66,6 @@ go_test(
         "//test/proto3pb:go_default_library",
         "@io_bazel_rules_go//proto/wkt:descriptor_go_proto",
         "@org_golang_google_genproto//googleapis/api/expr/v1alpha1:go_default_library",
+        "@org_golang_google_protobuf//types/known/structpb:go_default_library",
     ],
 )

cel/io.go

@@ -15,12 +15,21 @@
 package cel
 
 import (
+	"errors"
 	"fmt"
+	"time"
 
 	"github.com/google/cel-go/common"
+	"github.com/google/cel-go/common/types"
+	"github.com/google/cel-go/common/types/ref"
+	"github.com/google/cel-go/common/types/traits"
 	"github.com/google/cel-go/parser"
+	"google.golang.org/protobuf/proto"
 
 	exprpb "google.golang.org/genproto/googleapis/api/expr/v1alpha1"
+	anypb "google.golang.org/protobuf/types/known/anypb"
+	dpb "google.golang.org/protobuf/types/known/durationpb"
+	tpb "google.golang.org/protobuf/types/known/timestamppb"
 )
 
 // CheckedExprToAst converts a checked expression proto message to an Ast.
@@ -120,3 +129,178 @@ func AstToString(a *Ast) (string, error) {
 	info := a.SourceInfo()
 	return parser.Unparse(expr, info)
 }
+
+// RefValueToValue converts between ref.Val and api.expr.Value.
+// The result Value is the serialized proto form. The ref.Val must not be error or unknown.
+func RefValueToValue(res ref.Val) (*exprpb.Value, error) {
+	switch res.Type() {
+	case types.BoolType:
+		return &exprpb.Value{
+			Kind: &exprpb.Value_BoolValue{BoolValue: res.Value().(bool)}}, nil
+	case types.BytesType:
+		return &exprpb.Value{
+			Kind: &exprpb.Value_BytesValue{BytesValue: res.Value().([]byte)}}, nil
+	case types.DoubleType:
+		return &exprpb.Value{
+			Kind: &exprpb.Value_DoubleValue{DoubleValue: res.Value().(float64)}}, nil
+	case types.IntType:
+		return &exprpb.Value{
+			Kind: &exprpb.Value_Int64Value{Int64Value: res.Value().(int64)}}, nil
+	case types.ListType:
+		l := res.(traits.Lister)
+		sz := l.Size().(types.Int)
+		elts := make([]*exprpb.Value, 0, int64(sz))
+		for i := types.Int(0); i < sz; i++ {
+			v, err := RefValueToValue(l.Get(i))
+			if err != nil {
+				return nil, err
+			}
+			elts = append(elts, v)
+		}
+		return &exprpb.Value{
+			Kind: &exprpb.Value_ListValue{
+				ListValue: &exprpb.ListValue{Values: elts}}}, nil
+	case types.MapType:
+		mapper := res.(traits.Mapper)
+		sz := mapper.Size().(types.Int)
+		entries := make([]*exprpb.MapValue_Entry, 0, int64(sz))
+		for it := mapper.Iterator(); it.HasNext().(types.Bool); {
+			k := it.Next()
+			v := mapper.Get(k)
+			kv, err := RefValueToValue(k)
+			if err != nil {
+				return nil, err
+			}
+			vv, err := RefValueToValue(v)
+			if err != nil {
+				return nil, err
+			}
+			entries = append(entries, &exprpb.MapValue_Entry{Key: kv, Value: vv})
+		}
+		return &exprpb.Value{
+			Kind: &exprpb.Value_MapValue{
+				MapValue: &exprpb.MapValue{Entries: entries}}}, nil
+	case types.NullType:
+		return &exprpb.Value{
+			Kind: &exprpb.Value_NullValue{}}, nil
+	case types.StringType:
+		return &exprpb.Value{
+			Kind: &exprpb.Value_StringValue{StringValue: res.Value().(string)}}, nil
+	case types.TypeType:
+		typeName := res.(ref.Type).TypeName()
+		return &exprpb.Value{Kind: &exprpb.Value_TypeValue{TypeValue: typeName}}, nil
+	case types.UintType:
+		return &exprpb.Value{
+			Kind: &exprpb.Value_Uint64Value{Uint64Value: res.Value().(uint64)}}, nil
+	case types.DurationType:
+		d, ok := res.Value().(time.Duration)
+		if !ok {
+			return nil, errors.New("Expected time.Duration")
+		}
+		any, err := anypb.New(dpb.New(d))
+		if err != nil {
+			return nil, err
+		}
+		return &exprpb.Value{
+			Kind: &exprpb.Value_ObjectValue{ObjectValue: any}}, nil
+	case types.TimestampType:
+		t, ok := res.Value().(time.Time)
+		if !ok {
+			return nil, errors.New("Expected time.Time")
+		}
+		any, err := anypb.New(tpb.New(t))
+		if err != nil {
+			return nil, err
+		}
+		return &exprpb.Value{
+			Kind: &exprpb.Value_ObjectValue{ObjectValue: any}}, nil
+	default:
+		// Object type
+		pb, ok := res.Value().(proto.Message)
+		if !ok {
+			return nil, errors.New("Expected proto message")
+		}
+		any, err := anypb.New(pb)
+		if err != nil {
+			return nil, err
+		}
+		return &exprpb.Value{
+			Kind: &exprpb.Value_ObjectValue{ObjectValue: any}}, nil
+	}
+}
+
+var (
+	typeNameToTypeValue = map[string]*types.TypeValue{
+		"bool":      types.BoolType,
+		"bytes":     types.BytesType,
+		"double":    types.DoubleType,
+		"null_type": types.NullType,
+		"int":       types.IntType,
+		"list":      types.ListType,
+		"map":       types.MapType,
+		"string":    types.StringType,
+		"type":      types.TypeType,
+		"uint":      types.UintType,
+	}
+)
+
+// ValueToRefValue converts between exprpb.Value and ref.Val.
+func ValueToRefValue(adapter ref.TypeAdapter, v *exprpb.Value) (ref.Val, error) {
+	switch v.Kind.(type) {
+	case *exprpb.Value_NullValue:
+		return types.NullValue, nil
+	case *exprpb.Value_BoolValue:
+		return types.Bool(v.GetBoolValue()), nil
+	case *exprpb.Value_Int64Value:
+		return types.Int(v.GetInt64Value()), nil
+	case *exprpb.Value_Uint64Value:
+		return types.Uint(v.GetUint64Value()), nil
+	case *exprpb.Value_DoubleValue:
+		return types.Double(v.GetDoubleValue()), nil
+	case *exprpb.Value_StringValue:
+		return types.String(v.GetStringValue()), nil
+	case *exprpb.Value_BytesValue:
+		return types.Bytes(v.GetBytesValue()), nil
+	case *exprpb.Value_ObjectValue:
+		any := v.GetObjectValue()
+		msg, err := anypb.UnmarshalNew(any, proto.UnmarshalOptions{DiscardUnknown: true})
+		if err != nil {
+			return nil, err
+		}
+		return adapter.NativeToValue(msg.(proto.Message)), nil
+	case *exprpb.Value_MapValue:
+		m := v.GetMapValue()
+		entries := make(map[ref.Val]ref.Val)
+		for _, entry := range m.Entries {
+			key, err := ValueToRefValue(adapter, entry.Key)
+			if err != nil {
+				return nil, err
+			}
+			pb, err := ValueToRefValue(adapter, entry.Value)
+			if err != nil {
+				return nil, err
+			}
+			entries[key] = pb
+		}
+		return adapter.NativeToValue(entries), nil
+	case *exprpb.Value_ListValue:
+		l := v.GetListValue()
+		elts := make([]ref.Val, len(l.Values))
+		for i, e := range l.Values {
+			rv, err := ValueToRefValue(adapter, e)
+			if err != nil {
+				return nil, err
+			}
+			elts[i] = rv
+		}
+		return adapter.NativeToValue(elts), nil
+	case *exprpb.Value_TypeValue:
+		typeName := v.GetTypeValue()
+		tv, ok := typeNameToTypeValue[typeName]
+		if ok {
+			return tv, nil
+		}
+		return types.NewObjectTypeValue(typeName), nil
+	}
+	return nil, errors.New("unknown value")
+}

cel/io_test.go

@@ -15,14 +15,57 @@
 package cel
 
 import (
+	"fmt"
 	"testing"
 
 	"github.com/google/cel-go/checker/decls"
+	"github.com/google/cel-go/common/types"
+	"github.com/google/cel-go/test/proto3pb"
 	"google.golang.org/protobuf/proto"
 
 	exprpb "google.golang.org/genproto/googleapis/api/expr/v1alpha1"
 )
 
+func TestRefValueToValueRoundTrip(t *testing.T) {
+	tests := []struct {
+		value interface{}
+	}{
+		{value: types.NullValue},
+		{value: types.Bool(true)},
+		{value: types.String("abc")},
+		{value: types.Double(0.0)},
+		{value: types.Bytes(make([]byte, 0, 5))},
+		{value: types.Int(0)},
+		{value: types.Uint(0)},
+		{value: map[int64]int64{1: 1}},
+		{value: []interface{}{true, "abc"}},
+		{value: &proto3pb.TestAllTypes{SingleString: "abc"}},
+	}
+
+	env, err := NewEnv(Types(&proto3pb.TestAllTypes{}))
+	if err != nil {
+		t.Fatalf("NewEnv() failed: %v", err)
+	}
+
+	for i, tst := range tests {
+		tc := tst
+		t.Run(fmt.Sprintf("[%d]%v", i, tc.value), func(t *testing.T) {
+			refVal := env.TypeAdapter().NativeToValue(tc.value)
+			val, err := RefValueToValue(refVal)
+			if err != nil {
+				t.Fatalf("RefValueToValue(%v) failed with error: %v", refVal, err)
+			}
+			actual, err := ValueToRefValue(env.TypeAdapter(), val)
+			if err != nil {
+				t.Fatalf("ValueToRefValue() failed: &v", err)
+			}
+			if refVal.Equal(actual) != types.True {
+				t.Errorf("got val %v, wanted %v", actual, refVal)
+			}
+		})
+	}
+}
+
 func TestAstToProto(t *testing.T) {
 	stdEnv, _ := NewEnv(Declarations(
 		decls.NewVar("a", decls.Dyn),

common/types/BUILD.bazel

@@ -39,6 +39,9 @@ go_library(
         "//common/types/traits:go_default_library",
         "@com_github_stoewer_go_strcase//:go_default_library",
         "@org_golang_google_genproto//googleapis/api/expr/v1alpha1:go_default_library",
+        "@org_golang_google_genproto//googleapis/rpc/status:go_default_library",
+        "@org_golang_google_grpc//codes:go_default_library",
+        "@org_golang_google_grpc//status:go_default_library",
         "@org_golang_google_protobuf//encoding/protojson:go_default_library",
         "@org_golang_google_protobuf//proto:go_default_library",
         "@org_golang_google_protobuf//reflect/protoreflect:go_default_library",

server/BUILD.bazel

@@ -16,7 +16,6 @@ go_library(
         "//common:go_default_library",
         "//common/types:go_default_library",
         "//common/types/ref:go_default_library",
-        "//common/types/traits:go_default_library",
         "@com_google_cel_spec//proto/test/v1/proto2:test_all_types_go_proto",
         "@com_google_cel_spec//proto/test/v1/proto3:test_all_types_go_proto",
         "@org_golang_google_genproto//googleapis/api/expr/conformance/v1alpha1:go_default_library",
@@ -26,8 +25,6 @@ go_library(
         "@org_golang_google_grpc//status:go_default_library",
         "@org_golang_google_protobuf//proto:go_default_library",
         "@org_golang_google_protobuf//types/known/anypb:go_default_library",
-        "@org_golang_google_protobuf//types/known/durationpb:go_default_library",
-        "@org_golang_google_protobuf//types/known/timestamppb:go_default_library",
     ],
 )