JSON experiment.

internal/util/json.go

@@ -1,3 +1,5 @@
+//go:build !goexperiment.jsonv2
+
 package util
 
 import (

internal/util/json_v2.go

@@ -0,0 +1,52 @@
+//go:build goexperiment.jsonv2
+
+package util
+
+import (
+	"encoding/json/v2"
+	"math"
+	"strconv"
+	"time"
+	"unsafe"
+)
+
+type JSON struct{ Value any }
+
+func (j JSON) Scan(value any) error {
+	var buf []byte
+
+	switch v := value.(type) {
+	case []byte:
+		buf = v
+	case string:
+		buf = unsafe.Slice(unsafe.StringData(v), len(v))
+	case int64:
+		buf = strconv.AppendInt(nil, v, 10)
+	case float64:
+		buf = AppendNumber(nil, v)
+	case time.Time:
+		buf = append(buf, '"')
+		buf = v.AppendFormat(buf, time.RFC3339Nano)
+		buf = append(buf, '"')
+	case nil:
+		buf = []byte("null")
+	default:
+		panic(AssertErr())
+	}
+
+	return json.Unmarshal(buf, j.Value)
+}
+
+func AppendNumber(dst []byte, f float64) []byte {
+	switch {
+	case math.IsNaN(f):
+		dst = append(dst, "null"...)
+	case math.IsInf(f, 1):
+		dst = append(dst, "9.0e999"...)
+	case math.IsInf(f, -1):
+		dst = append(dst, "-9.0e999"...)
+	default:
+		return strconv.AppendFloat(dst, f, 'g', -1, 64)
+	}
+	return dst
+}