fix(encoding): fix decode for simple nodes

Decoding of nodes that are just simple values was erroring for both CBOR & JSON. This fixes the
issue as well as fixing it in the general unmarshal.

encoding/dagcbor/roundtrip_test.go

@@ -43,3 +43,19 @@ func TestRoundtrip(t *testing.T) {
 		Wish(t, n2, ShouldEqual, n)
 	})
 }
+
+func TestRoundtripSimple(t *testing.T) {
+	simple := fnb.CreateString("applesauce")
+	t.Run("encoding", func(t *testing.T) {
+		var buf bytes.Buffer
+		err := Encoder(simple, &buf)
+		Wish(t, err, ShouldEqual, nil)
+		Wish(t, buf.String(), ShouldEqual, `japplesauce`)
+	})
+	t.Run("decoding", func(t *testing.T) {
+		buf := bytes.NewBufferString(`japplesauce`)
+		simple2, err := Decoder(ipldfree.NodeBuilder(), buf)
+		Wish(t, err, ShouldEqual, nil)
+		Wish(t, simple2, ShouldEqual, simple)
+	})
+}

encoding/dagcbor/unmarshal.go

@@ -24,7 +24,10 @@ var (
 func Unmarshal(nb ipld.NodeBuilder, tokSrc shared.TokenSource) (ipld.Node, error) {
 	var tk tok.Token
 	done, err := tokSrc.Step(&tk)
-	if done || err != nil {
+	if err != nil {
+		return nil, err
+	}
+	if done && !tk.Type.IsValue() {
 		return nil, err
 	}
 	return unmarshal(nb, tokSrc, &tk)

encoding/dagjson/multicodec.go

@@ -37,7 +37,7 @@ func Decoder(nb ipld.NodeBuilder, r io.Reader) (ipld.Node, error) {
 	for {
 		_, err := r.Read(buf[:])
 		switch buf[0] {
-		case ' ', '\t', '\r', '\n': // continue
+		case ' ', 0x0, '\t', '\r', '\n': // continue
 		default:
 			return n, fmt.Errorf("unexpected content after end of json object")
 		}

encoding/dagjson/roundtrip_test.go

@@ -59,3 +59,19 @@ func TestRoundtrip(t *testing.T) {
 		Wish(t, n2, ShouldEqual, n)
 	})
 }
+
+func TestRoundtripSimple(t *testing.T) {
+	simple := fnb.CreateString("applesauce")
+	t.Run("encoding", func(t *testing.T) {
+		var buf bytes.Buffer
+		err := Encoder(simple, &buf)
+		Wish(t, err, ShouldEqual, nil)
+		Wish(t, buf.String(), ShouldEqual, `"applesauce"`)
+	})
+	t.Run("decoding", func(t *testing.T) {
+		buf := bytes.NewBufferString(`"applesauce"`)
+		simple2, err := Decoder(ipldfree.NodeBuilder(), buf)
+		Wish(t, err, ShouldEqual, nil)
+		Wish(t, simple2, ShouldEqual, simple)
+	})
+}

encoding/dagjson/unmarshal.go

@@ -19,7 +19,10 @@ import (
 func Unmarshal(nb ipld.NodeBuilder, tokSrc shared.TokenSource) (ipld.Node, error) {
 	var tk tok.Token
 	done, err := tokSrc.Step(&tk)
-	if done || err != nil {
+	if err != nil {
+		return nil, err
+	}
+	if done && !tk.Type.IsValue() {
 		return nil, err
 	}
 	return unmarshal(nb, tokSrc, &tk)

encoding/unmarshal.go

@@ -30,7 +30,10 @@ import (
 func Unmarshal(nb ipld.NodeBuilder, tokSrc shared.TokenSource) (ipld.Node, error) {
 	var tk tok.Token
 	done, err := tokSrc.Step(&tk)
-	if done || err != nil {
+	if err != nil {
+		return nil, err
+	}
+	if done && !tk.Type.IsValue() {
 		return nil, err
 	}
 	return unmarshal(nb, tokSrc, &tk)