a better encoder test, with a couple of fixes for bugs it uncovered.

R=rsc
DELTA=84  (65 added, 9 deleted, 10 changed)
OCL=31458
CL=31458

src/pkg/gob/encoder.go

@@ -12,17 +12,15 @@ import (
 	"sync";
 )
 
-import "fmt"	// TODO DELETE
-
 type Encoder struct {
 	sync.Mutex;	// each item must be sent atomically
-	sent	map[reflect.Type] uint;	// which types we've already sent
+	sent	map[reflect.Type] TypeId;	// which types we've already sent
 	state	*EncState;	// so we can encode integers, strings directly
 }
 
 func NewEncoder(w io.Writer) *Encoder {
 	enc := new(Encoder);
-	enc.sent = make(map[reflect.Type] uint);
+	enc.sent = make(map[reflect.Type] TypeId);
 	enc.state = new(EncState);
 	enc.state.w = w;	// the rest isn't important; all we need is buffer and writer
 	return enc;
@@ -32,15 +30,9 @@ func (enc *Encoder) badType(rt reflect.Type) {
 	enc.state.err = os.ErrorString("can't encode type " + rt.String());
 }
 
-func (enc *Encoder) sendType(rt reflect.Type) {
+func (enc *Encoder) sendType(origt reflect.Type) {
 	// Drill down to the base type.
-	for {
-		pt, ok := rt.(*reflect.PtrType);
-		if !ok {
-			break
-		}
-		rt = pt.Elem();
-	}
+	rt, indir_ := indirect(origt);
 
 	// We only send structs - everything else is basic or an error
 	switch t := rt.(type) {
@@ -62,9 +54,8 @@ func (enc *Encoder) sendType(rt reflect.Type) {
 		return;	// basic, array, etc; not a type to be sent.
 	}
 
-	// Have we already sent this type?
-	id, alreadySent := enc.sent[rt];
-	if alreadySent {
+	// Have we already sent this type?  This time we ask about the base type.
+	if id_, alreadySent := enc.sent[rt]; alreadySent {
 		return
 	}
 
@@ -76,7 +67,9 @@ func (enc *Encoder) sendType(rt reflect.Type) {
 	// Type:
 	Encode(enc.state.w, info.wire);
 	// Remember we've sent this type.
-	enc.sent[rt] = id;
+	enc.sent[rt] = info.typeId;
+	// Remember we've sent the top-level, possibly indirect type too.
+	enc.sent[origt] = info.typeId;
 	// Now send the inner types
 	st := rt.(*reflect.StructType);
 	for i := 0; i < st.NumField(); i++ {
@@ -92,9 +85,13 @@ func (enc *Encoder) Encode(e interface{}) os.Error {
 	defer enc.Unlock();
 
 	// Make sure the type is known to the other side.
-	enc.sendType(rt);
-	if enc.state.err != nil {
-		return enc.state.err
+	// First, have we already sent this type?
+	if id_, alreadySent := enc.sent[rt]; !alreadySent {
+		// No, so send it.
+		enc.sendType(rt);
+		if enc.state.err != nil {
+			return enc.state.err
+		}
 	}
 
 	// Identify the type of this top-level value.

src/pkg/gob/encoder_test.go

@@ -6,6 +6,7 @@ package gob
 
 import (
 	"bytes";
+"fmt";		// DELETE
 	"gob";
 	"os";
 	"reflect";
@@ -34,4 +35,59 @@ func TestBasicEncoder(t *testing.T) {
 	if enc.state.err != nil {
 		t.Error("encoder fail:", enc.state.err)
 	}
+
+	// Decode the result by hand to verify;
+	state := new(DecState);
+	state.r = b;
+	// The output should be:
+	// 1) -7: the type id of ET1
+	id1 := DecodeInt(state);
+	if id1 >= 0 {
+		t.Fatal("expected ET1 negative id; got", id1);
+	}
+	// 2) The wireType for ET1
+	wire1 := new(wireType);
+	err := Decode(b, wire1);
+	if err != nil {
+		t.Fatal("error decoding ET1 type:", err);
+	}
+	info := getTypeInfo(reflect.Typeof(ET1{}));
+	trueWire1 := &wireType{name:"ET1", s: info.typeId.gobType().(*structType)};
+	if !reflect.DeepEqual(wire1, trueWire1) {
+		t.Fatalf("invalid wireType for ET1: expected %+v; got %+v\n", *trueWire1, *wire1);
+	}
+	// 3) -8: the type id of ET2
+	id2 := DecodeInt(state);
+	if id2 >= 0 {
+		t.Fatal("expected ET2 negative id; got", id2);
+	}
+	// 4) The wireType for ET2
+	wire2 := new(wireType);
+	err = Decode(b, wire2);
+	if err != nil {
+		t.Fatal("error decoding ET2 type:", err);
+	}
+	info = getTypeInfo(reflect.Typeof(ET2{}));
+	trueWire2 := &wireType{name:"ET2", s: info.typeId.gobType().(*structType)};
+	if !reflect.DeepEqual(wire2, trueWire2) {
+		t.Fatalf("invalid wireType for ET2: expected %+v; got %+v\n", *trueWire2, *wire2);
+	}
+	// 5) The type id for the et1 value
+	newId1 := DecodeInt(state);
+	if newId1 != -id1 {
+		t.Fatal("expected Et1 id", -id1, "got", newId1);
+	}
+	// 6) The value of et1
+	newEt1 := new(ET1);
+	err = Decode(b, newEt1);
+	if err != nil {
+		t.Fatal("error decoding ET1 value:", err);
+	}
+	if !reflect.DeepEqual(et1, newEt1) {
+		t.Fatalf("invalid data for et1: expected %+v; got %+v\n", *et1, *newEt1);
+	}
+	// 7) EOF
+	if b.Len() != 0 {
+		t.Error("not at eof;", b.Len(), "bytes left")
+	}
 }

src/pkg/gob/type.go

@@ -142,6 +142,9 @@ type structType struct {
 }
 
 func (s *structType) safeString(seen map[TypeId] bool) string {
+	if s == nil {
+		return "<nil>"
+	}
 	if _, ok := seen[s._id]; ok {
 		return s.name
 	}