path: root/rlp/decode_test.go

package rlp

import (
    "bytes"
    "encoding/hex"
    "errors"
    "fmt"
    "io"
    "math/big"
    "reflect"
    "testing"

    "github.com/ethereum/go-ethereum/ethutil"
)

func TestStreamKind(t *testing.T) {
    tests := []struct {
        input    string
        wantKind Kind
        wantLen  uint64
    }{
        {"00", Byte, 0},
        {"01", Byte, 0},
        {"7F", Byte, 0},
        {"80", String, 0},
        {"B7", String, 55},
        {"B800", String, 0},
        {"B90400", String, 1024},
        {"BA000400", String, 1024},
        {"BB00000400", String, 1024},
        {"BFFFFFFFFFFFFFFFFF", String, ^uint64(0)},
        {"C0", List, 0},
        {"C8", List, 8},
        {"F7", List, 55},
        {"F800", List, 0},
        {"F804", List, 4},
        {"F90400", List, 1024},
        {"FFFFFFFFFFFFFFFFFF", List, ^uint64(0)},
    }

    for i, test := range tests {
        s := NewStream(bytes.NewReader(unhex(test.input)))
        kind, len, err := s.Kind()
        if err != nil {
            t.Errorf("test %d: Type returned error: %v", i, err)
            continue
        }
        if kind != test.wantKind {
            t.Errorf("test %d: kind mismatch: got %d, want %d", i, kind, test.wantKind)
        }
        if len != test.wantLen {
            t.Errorf("test %d: len mismatch: got %d, want %d", i, len, test.wantLen)
        }
    }
}

func TestStreamErrors(t *testing.T) {
    type calls []string
    tests := []struct {
        string
        calls
        error
    }{
        {"", calls{"Kind"}, io.EOF},
        {"", calls{"List"}, io.EOF},
        {"", calls{"Uint"}, io.EOF},
        {"C0", calls{"Bytes"}, ErrExpectedString},
        {"C0", calls{"Uint"}, ErrExpectedString},
        {"81", calls{"Bytes"}, io.ErrUnexpectedEOF},
        {"81", calls{"Uint"}, io.ErrUnexpectedEOF},
        {"BFFFFFFFFFFFFFFF", calls{"Bytes"}, io.ErrUnexpectedEOF},
        {"89000000000000000001", calls{"Uint"}, errors.New("rlp: string is larger than 64 bits")},
        {"00", calls{"List"}, ErrExpectedList},
        {"80", calls{"List"}, ErrExpectedList},
        {"C0", calls{"List", "Uint"}, EOL},
        {"C801", calls{"List", "Uint", "Uint"}, io.ErrUnexpectedEOF},
        {"C8C9", calls{"List", "Kind"}, ErrElemTooLarge},
        {"C3C2010201", calls{"List", "List", "Uint", "Uint", "ListEnd", "Uint"}, EOL},
        {"00", calls{"ListEnd"}, errNotInList},
        {"C40102", calls{"List", "Uint", "ListEnd"}, errNotAtEOL},
    }

testfor:
    for i, test := range tests {
        s := NewStream(bytes.NewReader(unhex(test.string)))
        rs := reflect.ValueOf(s)
        for j, call := range test.calls {
            fval := rs.MethodByName(call)
            ret := fval.Call(nil)
            err := "<nil>"
            if lastret := ret[len(ret)-1].Interface(); lastret != nil {
                err = lastret.(error).Error()
            }
            if j == len(test.calls)-1 {
                if err != test.error.Error() {
                    t.Errorf("test %d: last call (%s) error mismatch\ngot:  %s\nwant: %v",
                        i, call, err, test.error)
                }
            } else if err != "<nil>" {
                t.Errorf("test %d: call %d (%s) unexpected error: %q", i, j, call, err)
                continue testfor
            }
        }
    }
}

func TestStreamList(t *testing.T) {
    s := NewStream(bytes.NewReader(unhex("C80102030405060708")))

    len, err := s.List()
    if err != nil {
        t.Fatalf("List error: %v", err)
    }
    if len != 8 {
        t.Fatalf("List returned invalid length, got %d, want 8", len)
    }

    for i := uint64(1); i <= 8; i++ {
        v, err := s.Uint()
        if err != nil {
            t.Fatalf("Uint error: %v", err)
        }
        if i != v {
            t.Errorf("Uint returned wrong value, got %d, want %d", v, i)
        }
    }

    if _, err := s.Uint(); err != EOL {
        t.Errorf("Uint error mismatch, got %v, want %v", err, EOL)
    }
    if err = s.ListEnd(); err != nil {
        t.Fatalf("ListEnd error: %v", err)
    }
}

func TestDecodeErrors(t *testing.T) {
    r := bytes.NewReader(nil)

    if err := Decode(r, nil); err != errDecodeIntoNil {
        t.Errorf("Decode(r, nil) error mismatch, got %q, want %q", err, errDecodeIntoNil)
    }

    var nilptr *struct{}
    if err := Decode(r, nilptr); err != errDecodeIntoNil {
        t.Errorf("Decode(r, nilptr) error mismatch, got %q, want %q", err, errDecodeIntoNil)
    }

    if err := Decode(r, struct{}{}); err != errNoPointer {
        t.Errorf("Decode(r, struct{}{}) error mismatch, got %q, want %q", err, errNoPointer)
    }

    expectErr := "rlp: type chan bool is not RLP-serializable"
    if err := Decode(r, new(chan bool)); err == nil || err.Error() != expectErr {
        t.Errorf("Decode(r, new(chan bool)) error mismatch, got %q, want %q", err, expectErr)
    }

    if err := Decode(r, new(int)); err != io.EOF {
        t.Errorf("Decode(r, new(int)) error mismatch, got %q, want %q", err, io.EOF)
    }
}

type decodeTest struct {
    input string
    ptr   interface{}
    value interface{}
    error error
}

type simplestruct struct {
    A int
    B string
}

type recstruct struct {
    I     int
    Child *recstruct
}

var (
    veryBigInt = big.NewInt(0).Add(
        big.NewInt(0).Lsh(big.NewInt(0xFFFFFFFFFFFFFF), 16),
        big.NewInt(0xFFFF),
    )
)

var (
    sharedByteArray [5]byte
    sharedPtr       = new(*int)
)

var decodeTests = []decodeTest{
    // integers
    {input: "05", ptr: new(uint32), value: uint32(5)},
    {input: "80", ptr: new(uint32), value: uint32(0)},
    {input: "8105", ptr: new(uint32), value: uint32(5)},
    {input: "820505", ptr: new(uint32), value: uint32(0x0505)},
    {input: "83050505", ptr: new(uint32), value: uint32(0x050505)},
    {input: "8405050505", ptr: new(uint32), value: uint32(0x05050505)},
    {input: "850505050505", ptr: new(uint32), error: errors.New("rlp: string is larger than 32 bits")},
    {input: "C0", ptr: new(uint32), error: ErrExpectedString},

    // slices
    {input: "C0", ptr: new([]int), value: []int{}},
    {input: "C80102030405060708", ptr: new([]int), value: []int{1, 2, 3, 4, 5, 6, 7, 8}},

    // arrays
    {input: "C0", ptr: new([5]int), value: [5]int{}},
    {input: "C50102030405", ptr: new([5]int), value: [5]int{1, 2, 3, 4, 5}},
    {input: "C6010203040506", ptr: new([5]int), error: errors.New("rlp: input List has more than 5 elements")},

    // byte slices
    {input: "01", ptr: new([]byte), value: []byte{1}},
    {input: "80", ptr: new([]byte), value: []byte{}},
    {input: "8D6162636465666768696A6B6C6D", ptr: new([]byte), value: []byte("abcdefghijklm")},
    {input: "C0", ptr: new([]byte), value: []byte{}},
    {input: "C3010203", ptr: new([]byte), value: []byte{1, 2, 3}},
    {input: "C3820102", ptr: new([]byte), error: errors.New("rlp: string is larger than 8 bits")},

    // byte arrays
    {input: "01", ptr: new([5]byte), value: [5]byte{1}},
    {input: "80", ptr: new([5]byte), value: [5]byte{}},
    {input: "850102030405", ptr: new([5]byte), value: [5]byte{1, 2, 3, 4, 5}},
    {input: "C0", ptr: new([5]byte), value: [5]byte{}},
    {input: "C3010203", ptr: new([5]byte), value: [5]byte{1, 2, 3, 0, 0}},
    {input: "C3820102", ptr: new([5]byte), error: errors.New("rlp: string is larger than 8 bits")},
    {input: "86010203040506", ptr: new([5]byte), error: errStringDoesntFitArray},
    {input: "850101", ptr: new([5]byte), error: io.ErrUnexpectedEOF},

    // byte array reuse (should be zeroed)
    {input: "850102030405", ptr: &sharedByteArray, value: [5]byte{1, 2, 3, 4, 5}},
    {input: "8101", ptr: &sharedByteArray, value: [5]byte{1}}, // kind: String
    {input: "850102030405", ptr: &sharedByteArray, value: [5]byte{1, 2, 3, 4, 5}},
    {input: "01", ptr: &sharedByteArray, value: [5]byte{1}}, // kind: Byte
    {input: "C3010203", ptr: &sharedByteArray, value: [5]byte{1, 2, 3, 0, 0}},
    {input: "C101", ptr: &sharedByteArray, value: [5]byte{1}}, // kind: List

    // zero sized byte arrays
    {input: "80", ptr: new([0]byte), value: [0]byte{}},
    {input: "C0", ptr: new([0]byte), value: [0]byte{}},
    {input: "01", ptr: new([0]byte), error: errStringDoesntFitArray},
    {input: "8101", ptr: new([0]byte), error: errStringDoesntFitArray},

    // strings
    {input: "00", ptr: new(string), value: "\000"},
    {input: "8D6162636465666768696A6B6C6D", ptr: new(string), value: "abcdefghijklm"},
    {input: "C0", ptr: new(string), error: ErrExpectedString},

    // big ints
    {input: "01", ptr: new(*big.Int), value: big.NewInt(1)},
    {input: "89FFFFFFFFFFFFFFFFFF", ptr: new(*big.Int), value: veryBigInt},
    {input: "10", ptr: new(big.Int), value: *big.NewInt(16)}, // non-pointer also works
    {input: "C0", ptr: new(*big.Int), error: ErrExpectedString},

    // structs
    {input: "C0", ptr: new(simplestruct), value: simplestruct{0, ""}},
    {input: "C105", ptr: new(simplestruct), value: simplestruct{5, ""}},
    {input: "C50583343434", ptr: new(simplestruct), value: simplestruct{5, "444"}},
    {input: "C3010101", ptr: new(simplestruct), error: errors.New("rlp: input List has too many elements")},
    {
        input: "C501C302C103",
        ptr:   new(recstruct),
        value: recstruct{1, &recstruct{2, &recstruct{3, nil}}},
    },

    // pointers
    {input: "00", ptr: new(*int), value: (*int)(nil)},
    {input: "80", ptr: new(*int), value: (*int)(nil)},
    {input: "C0", ptr: new(*int), value: (*int)(nil)},
    {input: "07", ptr: new(*int), value: intp(7)},
    {input: "8108", ptr: new(*int), value: intp(8)},
    {input: "C109", ptr: new(*[]int), value: &[]int{9}},
    {input: "C58403030303", ptr: new(*[][]byte), value: &[][]byte{{3, 3, 3, 3}}},

    // pointer should be reset to nil
    {input: "05", ptr: sharedPtr, value: intp(5)},
    {input: "80", ptr: sharedPtr, value: (*int)(nil)},

    // interface{}
    {input: "00", ptr: new(interface{}), value: []byte{0}},
    {input: "01", ptr: new(interface{}), value: []byte{1}},
    {input: "80", ptr: new(interface{}), value: []byte{}},
    {input: "850505050505", ptr: new(interface{}), value: []byte{5, 5, 5, 5, 5}},
    {input: "C0", ptr: new(interface{}), value: []interface{}{}},
    {input: "C50183040404", ptr: new(interface{}), value: []interface{}{[]byte{1}, []byte{4, 4, 4}}},
}

func intp(i int) *int { return &i }

func TestDecode(t *testing.T) {
    for i, test := range decodeTests {
        input, err := hex.DecodeString(test.input)
        if err != nil {
            t.Errorf("test %d: invalid hex input %q", i, test.input)
            continue
        }
        err = Decode(bytes.NewReader(input), test.ptr)
        if err != nil && test.error == nil {
            t.Errorf("test %d: unexpected Decode error: %v\ndecoding into %T\ninput %q",
                i, err, test.ptr, test.input)
            continue
        }
        if test.error != nil && fmt.Sprint(err) != fmt.Sprint(test.error) {
            t.Errorf("test %d: Decode error mismatch\ngot  %v\nwant %v\ndecoding into %T\ninput %q",
                i, err, test.error, test.ptr, test.input)
            continue
        }
        deref := reflect.ValueOf(test.ptr).Elem().Interface()
        if err == nil && !reflect.DeepEqual(deref, test.value) {
            t.Errorf("test %d: value mismatch\ngot  %#v\nwant %#v\ndecoding into %T\ninput %q",
                i, deref, test.value, test.ptr, test.input)
        }
    }
}

type testDecoder struct{ called bool }

func (t *testDecoder) DecodeRLP(s *Stream) error {
    if _, err := s.Uint(); err != nil {
        return err
    }
    t.called = true
    return nil
}

func TestDecodeDecoder(t *testing.T) {
    var s struct {
        T1 testDecoder
        T2 *testDecoder
        T3 **testDecoder
    }
    if err := Decode(bytes.NewReader(unhex("C3010203")), &s); err != nil {
        t.Fatalf("Decode error: %v", err)
    }

    if !s.T1.called {
        t.Errorf("DecodeRLP was not called for (non-pointer) testDecoder")
    }

    if s.T2 == nil {
        t.Errorf("*testDecoder has not been allocated")
    } else if !s.T2.called {
        t.Errorf("DecodeRLP was not called for *testDecoder")
    }

    if s.T3 == nil || *s.T3 == nil {
        t.Errorf("**testDecoder has not been allocated")
    } else if !(*s.T3).called {
        t.Errorf("DecodeRLP was not called for **testDecoder")
    }
}

type byteDecoder byte

func (bd *byteDecoder) DecodeRLP(s *Stream) error {
    _, err := s.Uint()
    *bd = 255
    return err
}

func (bd byteDecoder) called() bool {
    return bd == 255
}

// This test verifies that the byte slice/byte array logic
// does not kick in for element types implementing Decoder.
func TestDecoderInByteSlice(t *testing.T) {
    var slice []byteDecoder
    if err := Decode(bytes.NewReader(unhex("C101")), &slice); err != nil {
        t.Errorf("unexpected Decode error %v", err)
    } else if !slice[0].called() {
        t.Errorf("DecodeRLP not called for slice element")
    }

    var array [1]byteDecoder
    if err := Decode(bytes.NewReader(unhex("C101")), &array); err != nil {
        t.Errorf("unexpected Decode error %v", err)
    } else if !array[0].called() {
        t.Errorf("DecodeRLP not called for array element")
    }
}

func ExampleDecode() {
    input, _ := hex.DecodeString("C90A1486666F6F626172")

    type example struct {
        A, B    int
        private int // private fields are ignored
        String  string
    }

    var s example
    err := Decode(bytes.NewReader(input), &s)
    if err != nil {
        fmt.Printf("Error: %v\n", err)
    } else {
        fmt.Printf("Decoded value: %#v\n", s)
    }
    // Output:
    // Decoded value: rlp.example{A:10, B:20, private:0, String:"foobar"}
}

func ExampleStream() {
    input, _ := hex.DecodeString("C90A1486666F6F626172")
    s := NewStream(bytes.NewReader(input))

    // Check what kind of value lies ahead
    kind, size, _ := s.Kind()
    fmt.Printf("Kind: %v size:%d\n", kind, size)

    // Enter the list
    if _, err := s.List(); err != nil {
        fmt.Printf("List error: %v\n", err)
        return
    }

    // Decode elements
    fmt.Println(s.Uint())
    fmt.Println(s.Uint())
    fmt.Println(s.Bytes())

    // Acknowledge end of list
    if err := s.ListEnd(); err != nil {
        fmt.Printf("ListEnd error: %v\n", err)
    }
    // Output:
    // Kind: List size:9
    // 10 <nil>
    // 20 <nil>
    // [102 111 111 98 97 114] <nil>
}

func BenchmarkDecode(b *testing.B) {
    enc := encTest(90000)
    b.SetBytes(int64(len(enc)))
    b.ReportAllocs()
    b.ResetTimer()

    for i := 0; i < b.N; i++ {
        var s []int
        r := bytes.NewReader(enc)
        if err := Decode(r, &s); err != nil {
            b.Fatalf("Decode error: %v", err)
        }
    }
}

func BenchmarkDecodeIntSliceReuse(b *testing.B) {
    enc := encTest(100000)
    b.SetBytes(int64(len(enc)))
    b.ReportAllocs()
    b.ResetTimer()

    var s []int
    for i := 0; i < b.N; i++ {
        r := bytes.NewReader(enc)
        if err := Decode(r, &s); err != nil {
            b.Fatalf("Decode error: %v", err)
        }
    }
}

func encTest(n int) []byte {
    s := make([]interface{}, n)
    for i := 0; i < n; i++ {
        s[i] = i
    }
    return ethutil.Encode(s)
}

func unhex(str string) []byte {
    b, err := hex.DecodeString(str)
    if err != nil {
        panic(fmt.Sprintf("invalid hex string: %q", str))
    }
    return b
}