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// Copyright 20011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// This file contains tests of the GobEncoder/GobDecoder support.
package gob
import (
"bytes"
"fmt"
"os"
"strings"
"testing"
)
// Types that implement the GobEncoder/Decoder interfaces.
type ByteStruct struct {
a byte // not an exported field
}
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.
// The relevant methods
func (g *ByteStruct) GobEncode() ([]byte, os.Error) {
b := make([]byte, 3)
b[0] = g.a
b[1] = g.a + 1
b[2] = g.a + 2
return b, nil
}
func (g *ByteStruct) GobDecode(data []byte) os.Error {
if g == nil {
return os.NewError("NIL RECEIVER")
}
// Expect N sequential-valued bytes.
if len(data) == 0 {
return os.EOF
}
g.a = data[0]
for i, c := range data {
if c != g.a+byte(i) {
return os.NewError("invalid data sequence")
}
}
return nil
}
func (g *StringStruct) GobEncode() ([]byte, os.Error) {
return []byte(g.s), nil
}
func (g *StringStruct) GobDecode(data []byte) os.Error {
// Expect N sequential-valued bytes.
if len(data) == 0 {
return os.EOF
}
a := data[0]
for i, c := range data {
if c != a+byte(i) {
return os.NewError("invalid data sequence")
}
}
g.s = string(data)
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.NewError("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
}
func (g *Gobber) GobDecode(data []byte) os.Error {
_, err := fmt.Sscanf(string(data), "VALUE=%d", (*int)(g))
return err
}
func (v ValueGobber) GobEncode() ([]byte, os.Error) {
return []byte(fmt.Sprintf("VALUE=%s", v)), nil
}
func (v *ValueGobber) GobDecode(data []byte) os.Error {
_, err := fmt.Sscanf(string(data), "VALUE=%s", (*string)(v))
return err
}
// Structs that include GobEncodable fields.
type GobTest0 struct {
X int // guarantee we have something in common with GobTest*
G *ByteStruct
}
type GobTest1 struct {
X int // guarantee we have something in common with GobTest*
G *StringStruct
}
type GobTest2 struct {
X int // guarantee we have something in common with GobTest*
G string // not a GobEncoder - should give us errors
}
type GobTest3 struct {
X int // guarantee we have something in common with GobTest*
G *Gobber
}
type GobTest4 struct {
X int // guarantee we have something in common with GobTest*
V ValueGobber
}
type GobTest5 struct {
X int // guarantee we have something in common with GobTest*
V *ValueGobber
}
type GobTestIgnoreEncoder struct {
X int // guarantee we have something in common with GobTest*
}
type GobTestValueEncDec struct {
X int // guarantee we have something in common with GobTest*
G StringStruct // not a pointer.
}
type GobTestIndirectEncDec struct {
X int // guarantee we have something in common with GobTest*
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.
enc := NewEncoder(b)
err := enc.Encode(GobTest0{17, &ByteStruct{'A'}})
if err != nil {
t.Fatal("encode error:", err)
}
dec := NewDecoder(b)
x := new(GobTest0)
err = dec.Decode(x)
if err != nil {
t.Fatal("decode error:", err)
}
if x.G.a != 'A' {
t.Errorf("expected 'A' got %c", x.G.a)
}
// Now a field that's not a structure.
b.Reset()
gobber := Gobber(23)
err = enc.Encode(GobTest3{17, &gobber})
if err != nil {
t.Fatal("encode error:", err)
}
y := new(GobTest3)
err = dec.Decode(y)
if err != nil {
t.Fatal("decode error:", err)
}
if *y.G != 23 {
t.Errorf("expected '23 got %d", *y.G)
}
}
// Even though the field is a value, we can still take its address
// and should be able to call the methods.
func TestGobEncoderValueField(t *testing.T) {
b := new(bytes.Buffer)
// First a field that's a structure.
enc := NewEncoder(b)
err := enc.Encode(GobTestValueEncDec{17, StringStruct{"HIJKL"}})
if err != nil {
t.Fatal("encode error:", err)
}
dec := NewDecoder(b)
x := new(GobTestValueEncDec)
err = dec.Decode(x)
if err != nil {
t.Fatal("decode error:", err)
}
if x.G.s != "HIJKL" {
t.Errorf("expected `HIJKL` got %s", x.G.s)
}
}
// GobEncode/Decode should work even if the value is
// more indirect than the receiver.
func TestGobEncoderIndirectField(t *testing.T) {
b := new(bytes.Buffer)
// First a field that's a structure.
enc := NewEncoder(b)
s := &StringStruct{"HIJKL"}
sp := &s
err := enc.Encode(GobTestIndirectEncDec{17, &sp})
if err != nil {
t.Fatal("encode error:", err)
}
dec := NewDecoder(b)
x := new(GobTestIndirectEncDec)
err = dec.Decode(x)
if err != nil {
t.Fatal("decode error:", err)
}
if (***x.G).s != "HIJKL" {
t.Errorf("expected `HIJKL` got %s", (***x.G).s)
}
}
// 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
// without exposing the contents of the object, which would
// defeat the purpose.
func TestGobEncoderFieldsOfDifferentType(t *testing.T) {
// first, string in field to byte in field
b := new(bytes.Buffer)
enc := NewEncoder(b)
err := enc.Encode(GobTest1{17, &StringStruct{"ABC"}})
if err != nil {
t.Fatal("encode error:", err)
}
dec := NewDecoder(b)
x := new(GobTest0)
err = dec.Decode(x)
if err != nil {
t.Fatal("decode error:", err)
}
if x.G.a != 'A' {
t.Errorf("expected 'A' got %c", x.G.a)
}
// now the other direction, byte in field to string in field
b.Reset()
err = enc.Encode(GobTest0{17, &ByteStruct{'X'}})
if err != nil {
t.Fatal("encode error:", err)
}
y := new(GobTest1)
err = dec.Decode(y)
if err != nil {
t.Fatal("decode error:", err)
}
if y.G.s != "XYZ" {
t.Fatalf("expected `XYZ` got %c", y.G.s)
}
}
// Test that we can encode a value and decode into a pointer.
func TestGobEncoderValueEncoder(t *testing.T) {
// first, string in field to byte in field
b := new(bytes.Buffer)
enc := NewEncoder(b)
err := enc.Encode(GobTest4{17, ValueGobber("hello")})
if err != nil {
t.Fatal("encode error:", err)
}
dec := NewDecoder(b)
x := new(GobTest5)
err = dec.Decode(x)
if err != nil {
t.Fatal("decode error:", err)
}
if *x.V != "hello" {
t.Errorf("expected `hello` got %s", x.V)
}
}
func TestGobEncoderFieldTypeError(t *testing.T) {
// GobEncoder to non-decoder: error
b := new(bytes.Buffer)
enc := NewEncoder(b)
err := enc.Encode(GobTest1{17, &StringStruct{"ABC"}})
if err != nil {
t.Fatal("encode error:", err)
}
dec := NewDecoder(b)
x := &GobTest2{}
err = dec.Decode(x)
if err == nil {
t.Fatal("expected decode error for mismatched fields (encoder to non-decoder)")
}
if strings.Index(err.String(), "type") < 0 {
t.Fatal("expected type error; got", err)
}
// Non-encoder to GobDecoder: error
b.Reset()
err = enc.Encode(GobTest2{17, "ABC"})
if err != nil {
t.Fatal("encode error:", err)
}
y := &GobTest1{}
err = dec.Decode(y)
if err == nil {
t.Fatal("expected decode error for mismatched fields (non-encoder to decoder)")
}
if strings.Index(err.String(), "type") < 0 {
t.Fatal("expected type error; got", err)
}
}
// Even though ByteStruct is a struct, it's treated as a singleton at the top level.
func TestGobEncoderStructSingleton(t *testing.T) {
b := new(bytes.Buffer)
enc := NewEncoder(b)
err := enc.Encode(&ByteStruct{'A'})
if err != nil {
t.Fatal("encode error:", err)
}
dec := NewDecoder(b)
x := new(ByteStruct)
err = dec.Decode(x)
if err != nil {
t.Fatal("decode error:", err)
}
if x.a != 'A' {
t.Errorf("expected 'A' got %c", x.a)
}
}
func TestGobEncoderNonStructSingleton(t *testing.T) {
b := new(bytes.Buffer)
enc := NewEncoder(b)
err := enc.Encode(Gobber(1234))
if err != nil {
t.Fatal("encode error:", err)
}
dec := NewDecoder(b)
var x Gobber
err = dec.Decode(&x)
if err != nil {
t.Fatal("decode error:", err)
}
if x != 1234 {
t.Errorf("expected 1234 got %d", x)
}
}
func TestGobEncoderIgnoreStructField(t *testing.T) {
b := new(bytes.Buffer)
// First a field that's a structure.
enc := NewEncoder(b)
err := enc.Encode(GobTest0{17, &ByteStruct{'A'}})
if err != nil {
t.Fatal("encode error:", err)
}
dec := NewDecoder(b)
x := new(GobTestIgnoreEncoder)
err = dec.Decode(x)
if err != nil {
t.Fatal("decode error:", err)
}
if x.X != 17 {
t.Errorf("expected 17 got %c", x.X)
}
}
func TestGobEncoderIgnoreNonStructField(t *testing.T) {
b := new(bytes.Buffer)
// First a field that's a structure.
enc := NewEncoder(b)
gobber := Gobber(23)
err := enc.Encode(GobTest3{17, &gobber})
if err != nil {
t.Fatal("encode error:", err)
}
dec := NewDecoder(b)
x := new(GobTestIgnoreEncoder)
err = dec.Decode(x)
if err != nil {
t.Fatal("decode error:", err)
}
if x.X != 17 {
t.Errorf("expected 17 got %c", x.X)
}
}
func TestGobEncoderIgnoreNilEncoder(t *testing.T) {
b := new(bytes.Buffer)
// First a field that's a structure.
enc := NewEncoder(b)
err := enc.Encode(GobTest0{X: 18}) // G is nil
if err != nil {
t.Fatal("encode error:", err)
}
dec := NewDecoder(b)
x := new(GobTest0)
err = dec.Decode(x)
if err != nil {
t.Fatal("decode error:", err)
}
if x.X != 18 {
t.Errorf("expected x.X = 18, got %v", x.X)
}
if x.G != nil {
t.Errorf("expected x.G = nil, got %v", x.G)
}
}
type gobDecoderBug0 struct {
foo, bar string
}
func (br *gobDecoderBug0) String() string {
return br.foo + "-" + br.bar
}
func (br *gobDecoderBug0) GobEncode() ([]byte, os.Error) {
return []byte(br.String()), nil
}
func (br *gobDecoderBug0) GobDecode(b []byte) os.Error {
br.foo = "foo"
br.bar = "bar"
return nil
}
// This was a bug: the receiver has a different indirection level
// than the variable.
func TestGobEncoderExtraIndirect(t *testing.T) {
gdb := &gobDecoderBug0{"foo", "bar"}
buf := new(bytes.Buffer)
e := NewEncoder(buf)
if err := e.Encode(gdb); err != nil {
t.Fatalf("encode: %v", err)
}
d := NewDecoder(buf)
var got *gobDecoderBug0
if err := d.Decode(&got); err != nil {
t.Fatalf("decode: %v", err)
}
if got.foo != gdb.foo || got.bar != gdb.bar {
t.Errorf("got = %q, want %q", got, gdb)
}
}