From 90fb31ffa0992a93cbe983ed2e12aacb26fe9d3b Mon Sep 17 00:00:00 2001
From: Masaaki Goshima <goccy54@gmail.com>
Date: Wed, 18 Nov 2020 03:26:32 +0900
Subject: [PATCH] Fix unsafe_New

---
 decode_ptr.go | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/decode_ptr.go b/decode_ptr.go
index 900af57..90a038a 100644
--- a/decode_ptr.go
+++ b/decode_ptr.go
@@ -1,12 +1,15 @@
 package json
 
 import (
+	"sync"
 	"unsafe"
 )
 
 type ptrDecoder struct {
-	dec decoder
-	typ *rtype
+	dec      decoder
+	typ      *rtype
+	mu       sync.Mutex
+	keepRefs []unsafe.Pointer
 }
 
 func newPtrDecoder(dec decoder, typ *rtype) *ptrDecoder {
@@ -14,24 +17,27 @@ func newPtrDecoder(dec decoder, typ *rtype) *ptrDecoder {
 }
 
 //go:linkname unsafe_New reflect.unsafe_New
-func unsafe_New(*rtype) uintptr
+func unsafe_New(*rtype) unsafe.Pointer
 
 func (d *ptrDecoder) decodeStream(s *stream, p uintptr) error {
 	newptr := unsafe_New(d.typ)
-	if err := d.dec.decodeStream(s, newptr); err != nil {
+	if err := d.dec.decodeStream(s, uintptr(newptr)); err != nil {
 		return err
 	}
-	**(**uintptr)(unsafe.Pointer(&p)) = newptr
+	**(**unsafe.Pointer)(unsafe.Pointer(&p)) = newptr
 	return nil
 }
 
 func (d *ptrDecoder) decode(buf []byte, cursor int64, p uintptr) (int64, error) {
+	d.mu.Lock()
 	newptr := unsafe_New(d.typ)
-	c, err := d.dec.decode(buf, cursor, newptr)
+	d.keepRefs = append(d.keepRefs, newptr)
+	**(**unsafe.Pointer)(unsafe.Pointer(&p)) = newptr
+	d.mu.Unlock()
+	c, err := d.dec.decode(buf, cursor, uintptr(newptr))
 	if err != nil {
 		return 0, err
 	}
 	cursor = c
-	**(**uintptr)(unsafe.Pointer(&p)) = newptr
 	return cursor, nil
 }