gob: test case for indirection to large field.

R=r
CC=golang-dev
https://golang.org/cl/4404048

src/pkg/gob/gobencdec_test.go

@@ -24,6 +24,10 @@ type StringStruct struct {
 	s string // not an exported field
 }
 
+type ArrayStruct struct {
+	a [8192]byte // not an exported field
+}
+
 type Gobber int
 
 type ValueGobber string // encodes with a value, decodes with a pointer.
@@ -74,6 +78,18 @@ func (g *StringStruct) GobDecode(data []byte) os.Error {
 	return nil
 }
 
+func (a *ArrayStruct) GobEncode() ([]byte, os.Error) {
+	return a.a[:], nil
+}
+
+func (a *ArrayStruct) GobDecode(data []byte) os.Error {
+	if len(data) != len(a.a) {
+		return os.ErrorString("wrong length in array decode")
+	}
+	copy(a.a[:], data)
+	return nil
+}
+
 func (g *Gobber) GobEncode() ([]byte, os.Error) {
 	return []byte(fmt.Sprintf("VALUE=%d", *g)), nil
 }
@@ -138,6 +154,16 @@ type GobTestIndirectEncDec struct {
 	G ***StringStruct // indirections to the receiver.
 }
 
+type GobTestArrayEncDec struct {
+	X int         // guarantee we have  something in common with GobTest*
+	A ArrayStruct // not a pointer.
+}
+
+type GobTestIndirectArrayEncDec struct {
+	X int            // guarantee we have  something in common with GobTest*
+	A ***ArrayStruct // indirections to a large receiver.
+}
+
 func TestGobEncoderField(t *testing.T) {
 	b := new(bytes.Buffer)
 	// First a field that's a structure.
@@ -216,6 +242,64 @@ func TestGobEncoderIndirectField(t *testing.T) {
 	}
 }
 
+// Test with a large field with methods.
+func TestGobEncoderArrayField(t *testing.T) {
+	b := new(bytes.Buffer)
+	enc := NewEncoder(b)
+	var a GobTestArrayEncDec
+	a.X = 17
+	for i := range a.A.a {
+		a.A.a[i] = byte(i)
+	}
+	err := enc.Encode(a)
+	if err != nil {
+		t.Fatal("encode error:", err)
+	}
+	dec := NewDecoder(b)
+	x := new(GobTestArrayEncDec)
+	err = dec.Decode(x)
+	if err != nil {
+		t.Fatal("decode error:", err)
+	}
+	for i, v := range x.A.a {
+		if v != byte(i) {
+			t.Errorf("expected %x got %x", byte(i), v)
+			break
+		}
+	}
+}
+
+// Test an indirection to a large field with methods.
+func TestGobEncoderIndirectArrayField(t *testing.T) {
+	b := new(bytes.Buffer)
+	enc := NewEncoder(b)
+	var a GobTestIndirectArrayEncDec
+	a.X = 17
+	var array ArrayStruct
+	ap := &array
+	app := &ap
+	a.A = &app
+	for i := range array.a {
+		array.a[i] = byte(i)
+	}
+	err := enc.Encode(a)
+	if err != nil {
+		t.Fatal("encode error:", err)
+	}
+	dec := NewDecoder(b)
+	x := new(GobTestIndirectArrayEncDec)
+	err = dec.Decode(x)
+	if err != nil {
+		t.Fatal("decode error:", err)
+	}
+	for i, v := range (***x.A).a {
+		if v != byte(i) {
+			t.Errorf("expected %x got %x", byte(i), v)
+			break
+		}
+	}
+}
+
 // As long as the fields have the same name and implement the
 // interface, we can cross-connect them.  Not sure it's useful
 // and may even be bad but it works and it's hard to prevent