peformance tuning

Signed-off-by: Tim Ramlot <[email protected]>

Author: inteon

fieldpath/serialize-pe.go

@@ -17,10 +17,10 @@ limitations under the License.
 package fieldpath
 
 import (
+	"bytes"
 	"errors"
 	"fmt"
 	"strconv"
-	"strings"
 
 	"github.com/go-json-experiment/json"
 	"sigs.k8s.io/structured-merge-diff/v6/value"
@@ -97,36 +97,45 @@ func DeserializePathElement(s string) (PathElement, error) {
 
 // SerializePathElement serializes a path element
 func SerializePathElement(pe PathElement) (string, error) {
-	builder := strings.Builder{}
+	builder := bytes.Buffer{}
+	if err := serializePathElementBuilder(pe, &builder); err != nil {
+		return "", err
+	}
+	return builder.String(), nil
+}
 
+func serializePathElementBuilder(pe PathElement, builder *bytes.Buffer) error {
 	switch {
 	case pe.FieldName != nil:
 		if _, err := builder.Write(peFieldSepBytes); err != nil {
-			return "", err
+			return err
+		}
+		if _, err := builder.WriteString(*pe.FieldName); err != nil {
+			return err
 		}
-		builder.WriteString(*pe.FieldName)
 	case pe.Key != nil:
 		if _, err := builder.Write(peKeySepBytes); err != nil {
-			return "", err
+			return err
 		}
-		if err := json.MarshalWrite(&builder, *pe.Key, json.Deterministic(true)); err != nil {
-			return "", err
+		if err := json.MarshalWrite(builder, pe.Key, json.Deterministic(true)); err != nil {
+			return err
 		}
 	case pe.Value != nil:
 		if _, err := builder.Write(peValueSepBytes); err != nil {
-			return "", err
+			return err
 		}
-		if err := json.MarshalWrite(&builder, (*pe.Value).Unstructured(), json.Deterministic(true)); err != nil {
-			return "", err
+		if err := json.MarshalWrite(builder, (*pe.Value).Unstructured(), json.Deterministic(true)); err != nil {
+			return err
 		}
 	case pe.Index != nil:
 		if _, err := builder.Write(peIndexSepBytes); err != nil {
-			return "", err
+			return err
+		}
+		if _, err := builder.WriteString(strconv.Itoa(*pe.Index)); err != nil {
+			return err
 		}
-		builder.WriteString(strconv.Itoa(*pe.Index))
 	default:
-		return "", errors.New("invalid PathElement")
+		return errors.New("invalid PathElement")
 	}
-
-	return builder.String(), nil
+	return nil
 }

fieldpath/serialize.go

@@ -17,9 +17,11 @@ limitations under the License.
 package fieldpath
 
 import (
+	"bytes"
 	"fmt"
 	"io"
 	"sort"
+	"sync"
 
 	"github.com/go-json-experiment/json"
 	"github.com/go-json-experiment/json/jsontext"
@@ -33,13 +35,24 @@ func (s *Set) ToJSONStream(w io.Writer) error {
 	return json.MarshalWrite(w, (*setContentsV1)(s))
 }
 
+var pool = sync.Pool{
+	New: func() any {
+		return &bytes.Buffer{}
+	},
+}
+
 func writePathKey(enc *jsontext.Encoder, pe PathElement) error {
-	key, err := SerializePathElement(pe)
-	if err != nil {
+	builder := pool.Get().(*bytes.Buffer)
+	defer func() {
+		builder.Reset()
+		pool.Put(builder)
+	}()
+
+	if err := serializePathElementBuilder(pe, builder); err != nil {
 		return err
 	}
 
-	if err := enc.WriteToken(jsontext.String(key)); err != nil {
+	if err := enc.WriteToken(jsontext.String(builder.String())); err != nil {
 		return err
 	}
 	return nil