From 181a21c67c8dafe027cd7fb43fe3f68eaf2a52ea Mon Sep 17 00:00:00 2001
From: Felix Lange <fjl@twurst.com>
Date: Wed, 25 Mar 2015 16:46:29 +0100
Subject: [PATCH] rlp: encode nil array pointers as empty list or string
---
rlp/encode.go | 34 ++++++++++++++++++++++++++--------
rlp/encode_test.go | 2 ++
2 files changed, 28 insertions(+), 8 deletions(-)
diff --git a/rlp/encode.go b/rlp/encode.go
index 289bc4eaa..6cf6776d6 100644
--- a/rlp/encode.go
+++ b/rlp/encode.go
@@ -87,6 +87,8 @@ func (e flatenc) EncodeRLP(out io.Writer) error {
// To encode a pointer, the value being pointed to is encoded. For nil
// pointers, Encode will encode the zero value of the type. A nil
// pointer to a struct type always encodes as an empty RLP list.
+// A nil pointer to an array encodes as an empty list (or empty string
+// if the array has element type byte).
//
// Struct values are encoded as an RLP list of all their encoded
// public fields. Recursive struct types are supported.
@@ -532,21 +534,37 @@ func makePtrWriter(typ reflect.Type) (writer, error) {
if err != nil {
return nil, err
}
- zero := reflect.Zero(typ.Elem())
+
+ // determine nil pointer handler
+ var nilfunc func(*encbuf) error
kind := typ.Elem().Kind()
- writer := func(val reflect.Value, w *encbuf) error {
- switch {
- case !val.IsNil():
- return etypeinfo.writer(val.Elem(), w)
- case kind == reflect.Struct:
- // encoding the zero value of a struct could trigger
+ switch {
+ case kind == reflect.Array && isByte(typ.Elem().Elem()):
+ nilfunc = func(w *encbuf) error {
+ w.str = append(w.str, 0x80)
+ return nil
+ }
+ case kind == reflect.Struct || kind == reflect.Array:
+ nilfunc = func(w *encbuf) error {
+ // encoding the zero value of a struct/array could trigger
// infinite recursion, avoid that.
w.listEnd(w.list())
return nil
- default:
+ }
+ default:
+ zero := reflect.Zero(typ.Elem())
+ nilfunc = func(w *encbuf) error {
return etypeinfo.writer(zero, w)
}
}
+
+ writer := func(val reflect.Value, w *encbuf) error {
+ if val.IsNil() {
+ return nilfunc(w)
+ } else {
+ return etypeinfo.writer(val.Elem(), w)
+ }
+ }
return writer, err
}
diff --git a/rlp/encode_test.go b/rlp/encode_test.go
index 611514bda..6eb930d6c 100644
--- a/rlp/encode_test.go
+++ b/rlp/encode_test.go
@@ -202,8 +202,10 @@ var encTests = []encTest{
{val: (*uint)(nil), output: "80"},
{val: (*string)(nil), output: "80"},
{val: (*[]byte)(nil), output: "80"},
+ {val: (*[10]byte)(nil), output: "80"},
{val: (*big.Int)(nil), output: "80"},
{val: (*[]string)(nil), output: "C0"},
+ {val: (*[10]string)(nil), output: "C0"},
{val: (*[]interface{})(nil), output: "C0"},
{val: (*[]struct{ uint })(nil), output: "C0"},
{val: (*interface{})(nil), output: "C0"},
--
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