Commit 9ddc2b56 authored by Rob Pike's avatar Rob Pike

gob: fix allocation for singletons.

Code was double-allocating in some cases.
Fixes #2267.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/5093042
parent c55d0c4d
......@@ -467,20 +467,17 @@ func allocate(rtyp reflect.Type, p uintptr, indir int) uintptr {
// decodeSingle decodes a top-level value that is not a struct and stores it through p.
// Such values are preceded by a zero, making them have the memory layout of a
// struct field (although with an illegal field number).
func (dec *Decoder) decodeSingle(engine *decEngine, ut *userTypeInfo, p uintptr) (err os.Error) {
indir := ut.indir
if ut.isGobDecoder {
indir = int(ut.decIndir)
}
p = allocate(ut.base, p, indir)
func (dec *Decoder) decodeSingle(engine *decEngine, ut *userTypeInfo, basep uintptr) (err os.Error) {
state := dec.newDecoderState(&dec.buf)
state.fieldnum = singletonField
basep := p
delta := int(state.decodeUint())
if delta != 0 {
errorf("decode: corrupted data: non-zero delta for singleton")
}
instr := &engine.instr[singletonField]
if instr.indir != ut.indir {
return os.NewError("gob: internal error: inconsistent indirection")
}
ptr := unsafe.Pointer(basep) // offset will be zero
if instr.indir > 1 {
ptr = decIndirect(ptr, instr.indir)
......@@ -1069,10 +1066,7 @@ func (dec *Decoder) typeString(remoteId typeId) string {
// compileSingle compiles the decoder engine for a non-struct top-level value, including
// GobDecoders.
func (dec *Decoder) compileSingle(remoteId typeId, ut *userTypeInfo) (engine *decEngine, err os.Error) {
rt := ut.base
if ut.isGobDecoder {
rt = ut.user
}
rt := ut.user
engine = new(decEngine)
engine.instr = make([]decInstr, 1) // one item
name := rt.String() // best we can do
......@@ -1202,7 +1196,7 @@ func (dec *Decoder) decodeValue(wireId typeId, val reflect.Value) {
dec.decodeIgnoredValue(wireId)
return
}
// Dereference down to the underlying struct type.
// Dereference down to the underlying type.
ut := userType(val.Type())
base := ut.base
var enginePtr **decEngine
......
......@@ -424,7 +424,7 @@ func TestGobEncoderNonStructSingleton(t *testing.T) {
t.Fatal("decode error:", err)
}
if x != 1234 {
t.Errorf("expected 1234 got %c", x)
t.Errorf("expected 1234 got %d", x)
}
}
......@@ -488,3 +488,40 @@ func TestGobEncoderIgnoreNilEncoder(t *testing.T) {
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)
}
}
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