asn1: Fixes and additions to marshalling

Marshalling:
* Fixes several silly bugs.
* Support the RawContents type.
* Support the RawValue type.
* Recurse into nested interface{}.

Both directions:
* Better handling of SETs. You can now tag an element in a
  structure with "set" to get the correct tag for serialisation.
* For types that aren't in a structure, you can now name them
  with "SET" on the end.
* SETs are no longer implicitly treated as SEQUENCEs.

R=rsc
CC=golang-dev
http://codereview.appspot.com/201049

5 files changed, 159 insertions, 45 deletions

diff --git a/src/pkg/asn1/asn1.go b/src/pkg/asn1/asn1.go
index 430b035f5..fb33afcc2 100644
--- a/src/pkg/asn1/asn1.go
+++ b/src/pkg/asn1/asn1.go
@@ -410,11 +410,6 @@ func parseTagAndLength(bytes []byte, initOffset int) (ret tagAndLength, offset i
 		}
 	}
 
-	// We magically map SET and SET OF to SEQUENCE and SEQUENCE OF
-	// because we treat everything as ordered.
-	if ret.tag == tagSet {
-		ret.tag = tagSequence
-	}
 	return
 }
 
diff --git a/src/pkg/asn1/asn1_test.go b/src/pkg/asn1/asn1_test.go
index 43c746895..d5779d017 100644
--- a/src/pkg/asn1/asn1_test.go
+++ b/src/pkg/asn1/asn1_test.go
@@ -224,16 +224,17 @@ func newString(s string) *string { return &s }
 func newBool(b bool) *bool { return &b }
 
 var parseFieldParametersTestData []parseFieldParametersTest = []parseFieldParametersTest{
-	parseFieldParametersTest{"", fieldParameters{false, false, nil, nil, 0}},
-	parseFieldParametersTest{"ia5", fieldParameters{false, false, nil, nil, tagIA5String}},
-	parseFieldParametersTest{"printable", fieldParameters{false, false, nil, nil, tagPrintableString}},
-	parseFieldParametersTest{"optional", fieldParameters{true, false, nil, nil, 0}},
-	parseFieldParametersTest{"explicit", fieldParameters{false, true, nil, new(int), 0}},
-	parseFieldParametersTest{"optional,explicit", fieldParameters{true, true, nil, new(int), 0}},
-	parseFieldParametersTest{"default:42", fieldParameters{false, false, newInt64(42), nil, 0}},
-	parseFieldParametersTest{"tag:17", fieldParameters{false, false, nil, newInt(17), 0}},
-	parseFieldParametersTest{"optional,explicit,default:42,tag:17", fieldParameters{true, true, newInt64(42), newInt(17), 0}},
-	parseFieldParametersTest{"optional,explicit,default:42,tag:17,rubbish1", fieldParameters{true, true, newInt64(42), newInt(17), 0}},
+	parseFieldParametersTest{"", fieldParameters{}},
+	parseFieldParametersTest{"ia5", fieldParameters{stringType: tagIA5String}},
+	parseFieldParametersTest{"printable", fieldParameters{stringType: tagPrintableString}},
+	parseFieldParametersTest{"optional", fieldParameters{optional: true}},
+	parseFieldParametersTest{"explicit", fieldParameters{explicit: true, tag: new(int)}},
+	parseFieldParametersTest{"optional,explicit", fieldParameters{optional: true, explicit: true, tag: new(int)}},
+	parseFieldParametersTest{"default:42", fieldParameters{defaultValue: newInt64(42)}},
+	parseFieldParametersTest{"tag:17", fieldParameters{tag: newInt(17)}},
+	parseFieldParametersTest{"optional,explicit,default:42,tag:17", fieldParameters{optional: true, explicit: true, defaultValue: newInt64(42), tag: newInt(17)}},
+	parseFieldParametersTest{"optional,explicit,default:42,tag:17,rubbish1", fieldParameters{true, true, newInt64(42), newInt(17), 0, false}},
+	parseFieldParametersTest{"set", fieldParameters{set: true}},
 }
 
 func TestParseFieldParameters(t *testing.T) {
@@ -321,9 +322,9 @@ type AlgorithmIdentifier struct {
 	Algorithm ObjectIdentifier
 }
 
-type RDNSequence []RelativeDistinguishedName
+type RDNSequence []RelativeDistinguishedNameSET
 
-type RelativeDistinguishedName []AttributeTypeAndValue
+type RelativeDistinguishedNameSET []AttributeTypeAndValue
 
 type AttributeTypeAndValue struct {
 	Type  ObjectIdentifier
@@ -392,21 +393,21 @@ var derEncodedSelfSignedCert = Certificate{
 		SerialNumber: RawValue{Class: 0, Tag: 2, IsCompound: false, Bytes: []uint8{0x0, 0x8c, 0xc3, 0x37, 0x92, 0x10, 0xec, 0x2c, 0x98}},
 		SignatureAlgorithm: AlgorithmIdentifier{Algorithm: ObjectIdentifier{1, 2, 840, 113549, 1, 1, 5}},
 		Issuer: RDNSequence{
-			RelativeDistinguishedName{AttributeTypeAndValue{Type: ObjectIdentifier{2, 5, 4, 6}, Value: "XX"}},
-			RelativeDistinguishedName{AttributeTypeAndValue{Type: ObjectIdentifier{2, 5, 4, 8}, Value: "Some-State"}},
-			RelativeDistinguishedName{AttributeTypeAndValue{Type: ObjectIdentifier{2, 5, 4, 7}, Value: "City"}},
-			RelativeDistinguishedName{AttributeTypeAndValue{Type: ObjectIdentifier{2, 5, 4, 10}, Value: "Internet Widgits Pty Ltd"}},
-			RelativeDistinguishedName{AttributeTypeAndValue{Type: ObjectIdentifier{2, 5, 4, 3}, Value: "false.example.com"}},
-			RelativeDistinguishedName{AttributeTypeAndValue{Type: ObjectIdentifier{1, 2, 840, 113549, 1, 9, 1}, Value: "false@example.com"}},
+			RelativeDistinguishedNameSET{AttributeTypeAndValue{Type: ObjectIdentifier{2, 5, 4, 6}, Value: "XX"}},
+			RelativeDistinguishedNameSET{AttributeTypeAndValue{Type: ObjectIdentifier{2, 5, 4, 8}, Value: "Some-State"}},
+			RelativeDistinguishedNameSET{AttributeTypeAndValue{Type: ObjectIdentifier{2, 5, 4, 7}, Value: "City"}},
+			RelativeDistinguishedNameSET{AttributeTypeAndValue{Type: ObjectIdentifier{2, 5, 4, 10}, Value: "Internet Widgits Pty Ltd"}},
+			RelativeDistinguishedNameSET{AttributeTypeAndValue{Type: ObjectIdentifier{2, 5, 4, 3}, Value: "false.example.com"}},
+			RelativeDistinguishedNameSET{AttributeTypeAndValue{Type: ObjectIdentifier{1, 2, 840, 113549, 1, 9, 1}, Value: "false@example.com"}},
 		},
 		Validity: Validity{NotBefore: &time.Time{Year: 2009, Month: 10, Day: 8, Hour: 0, Minute: 25, Second: 53, Weekday: 0, ZoneOffset: 0, Zone: ""}, NotAfter: &time.Time{Year: 2010, Month: 10, Day: 8, Hour: 0, Minute: 25, Second: 53, Weekday: 0, ZoneOffset: 0, Zone: ""}},
 		Subject: RDNSequence{
-			RelativeDistinguishedName{AttributeTypeAndValue{Type: ObjectIdentifier{2, 5, 4, 6}, Value: "XX"}},
-			RelativeDistinguishedName{AttributeTypeAndValue{Type: ObjectIdentifier{2, 5, 4, 8}, Value: "Some-State"}},
-			RelativeDistinguishedName{AttributeTypeAndValue{Type: ObjectIdentifier{2, 5, 4, 7}, Value: "City"}},
-			RelativeDistinguishedName{AttributeTypeAndValue{Type: ObjectIdentifier{2, 5, 4, 10}, Value: "Internet Widgits Pty Ltd"}},
-			RelativeDistinguishedName{AttributeTypeAndValue{Type: ObjectIdentifier{2, 5, 4, 3}, Value: "false.example.com"}},
-			RelativeDistinguishedName{AttributeTypeAndValue{Type: ObjectIdentifier{1, 2, 840, 113549, 1, 9, 1}, Value: "false@example.com"}},
+			RelativeDistinguishedNameSET{AttributeTypeAndValue{Type: ObjectIdentifier{2, 5, 4, 6}, Value: "XX"}},
+			RelativeDistinguishedNameSET{AttributeTypeAndValue{Type: ObjectIdentifier{2, 5, 4, 8}, Value: "Some-State"}},
+			RelativeDistinguishedNameSET{AttributeTypeAndValue{Type: ObjectIdentifier{2, 5, 4, 7}, Value: "City"}},
+			RelativeDistinguishedNameSET{AttributeTypeAndValue{Type: ObjectIdentifier{2, 5, 4, 10}, Value: "Internet Widgits Pty Ltd"}},
+			RelativeDistinguishedNameSET{AttributeTypeAndValue{Type: ObjectIdentifier{2, 5, 4, 3}, Value: "false.example.com"}},
+			RelativeDistinguishedNameSET{AttributeTypeAndValue{Type: ObjectIdentifier{1, 2, 840, 113549, 1, 9, 1}, Value: "false@example.com"}},
 		},
 		PublicKey: PublicKeyInfo{
 			Algorithm: AlgorithmIdentifier{Algorithm: ObjectIdentifier{1, 2, 840, 113549, 1, 1, 1}},
diff --git a/src/pkg/asn1/common.go b/src/pkg/asn1/common.go
index a3278b639..87cb670ea 100644
--- a/src/pkg/asn1/common.go
+++ b/src/pkg/asn1/common.go
@@ -68,6 +68,7 @@ type fieldParameters struct {
 	defaultValue *int64 // a default value for INTEGER typed fields (maybe nil).
 	tag          *int   // the EXPLICIT or IMPLICIT tag (maybe nil).
 	stringType   int    // the string tag to use when marshaling.
+	set          bool   // true iff this should be encoded as a SET
 
 	// Invariants:
 	//   if explicit is set, tag is non-nil.
@@ -103,6 +104,8 @@ func parseFieldParameters(str string) (ret fieldParameters) {
 				ret.tag = new(int)
 				*ret.tag = i
 			}
+		case part == "set":
+			ret.set = true
 		}
 	}
 	return
@@ -132,6 +135,9 @@ func getUniversalType(t reflect.Type) (tagNumber int, isCompound, ok bool) {
 		if _, ok := t.(*reflect.SliceType).Elem().(*reflect.Uint8Type); ok {
 			return tagOctetString, false, true
 		}
+		if strings.HasSuffix(t.Name(), "SET") {
+			return tagSet, true, true
+		}
 		return tagSequence, true, true
 	case *reflect.StringType:
 		return tagPrintableString, false, true
diff --git a/src/pkg/asn1/marshal.go b/src/pkg/asn1/marshal.go
index 40a52b662..0ee593ef8 100644
--- a/src/pkg/asn1/marshal.go
+++ b/src/pkg/asn1/marshal.go
@@ -71,23 +71,27 @@ func (f *forkableWriter) writeTo(out io.Writer) (n int, err os.Error) {
 	return
 }
 
-func marshalBase128Int(out *forkableWriter, i int64) (err os.Error) {
-	if i == 0 {
+func marshalBase128Int(out *forkableWriter, n int64) (err os.Error) {
+	if n == 0 {
 		err = out.WriteByte(0)
 		return
 	}
 
-	for i > 0 {
-		next := i >> 7
-		o := byte(i & 0x7f)
-		if next > 0 {
+	l := 0
+	for i := n; i > 0; i >>= 7 {
+		l++
+	}
+
+	for i := l - 1; i >= 0; i-- {
+		o := byte(n >> uint(i*7))
+		o &= 0x7f
+		if i != 0 {
 			o |= 0x80
 		}
 		err = out.WriteByte(o)
 		if err != nil {
 			return
 		}
-		i = next
 	}
 
 	return nil
@@ -106,6 +110,32 @@ func base128Length(i int) (numBytes int) {
 	return
 }
 
+func marshalInt64(out *forkableWriter, i int64) (err os.Error) {
+	n := int64Length(i)
+
+	for ; n > 0; n-- {
+		err = out.WriteByte(byte(i >> uint((n-1)*8)))
+		if err != nil {
+			return
+		}
+	}
+
+	return nil
+}
+
+func int64Length(i int64) (numBytes int) {
+	if i == 0 {
+		return 1
+	}
+
+	for i > 0 {
+		numBytes++
+		i >>= 8
+	}
+
+	return
+}
+
 func marshalTagAndLength(out *forkableWriter, t tagAndLength) (err os.Error) {
 	b := uint8(t.class) << 6
 	if t.isCompound {
@@ -130,11 +160,12 @@ func marshalTagAndLength(out *forkableWriter, t tagAndLength) (err os.Error) {
 	}
 
 	if t.length >= 128 {
-		err = out.WriteByte(byte(base128Length(t.length)))
+		l := int64Length(int64(t.length))
+		err = out.WriteByte(0x80 | byte(l))
 		if err != nil {
 			return
 		}
-		err = marshalBase128Int(out, int64(t.length))
+		err = marshalInt64(out, int64(t.length))
 		if err != nil {
 			return
 		}
@@ -276,6 +307,14 @@ func marshalUTCTime(out *forkableWriter, t *time.Time) (err os.Error) {
 	return
 }
 
+func stripTagAndLength(in []byte) []byte {
+	_, offset, err := parseTagAndLength(in, 0)
+	if err != nil {
+		return in
+	}
+	return in[offset:]
+}
+
 func marshalBody(out *forkableWriter, value reflect.Value, params fieldParameters) (err os.Error) {
 	switch value.Type() {
 	case timeType:
@@ -294,12 +333,35 @@ func marshalBody(out *forkableWriter, value reflect.Value, params fieldParameter
 			return out.WriteByte(0)
 		}
 	case *reflect.IntValue:
-		return marshalBase128Int(out, int64(v.Get()))
+		return marshalInt64(out, int64(v.Get()))
 	case *reflect.Int64Value:
-		return marshalBase128Int(out, v.Get())
+		return marshalInt64(out, v.Get())
 	case *reflect.StructValue:
 		t := v.Type().(*reflect.StructType)
-		for i := 0; i < t.NumField(); i++ {
+
+		startingField := 0
+
+		// If the first element of the structure is a non-empty
+		// RawContents, then we don't bother serialising the rest.
+		if t.NumField() > 0 && t.Field(0).Type == rawContentsType {
+			s := v.Field(0).(*reflect.SliceValue)
+			if s.Len() > 0 {
+				bytes := make([]byte, s.Len())
+				for i := 0; i < s.Len(); i++ {
+					bytes[i] = s.Elem(i).(*reflect.Uint8Value).Get()
+				}
+				/* The RawContents will contain the tag and
+				 * length fields but we'll also be writing
+				 * those outselves, so we strip them out of
+				 * bytes */
+				_, err = out.Write(stripTagAndLength(bytes))
+				return
+			} else {
+				startingField = 1
+			}
+		}
+
+		for i := startingField; i < t.NumField(); i++ {
 			var pre *forkableWriter
 			pre, out = out.fork()
 			err = marshalField(pre, v.Field(i), parseFieldParameters(t.Field(i).Tag))
@@ -321,7 +383,9 @@ func marshalBody(out *forkableWriter, value reflect.Value, params fieldParameter
 
 		var params fieldParameters
 		for i := 0; i < v.Len(); i++ {
-			err = marshalField(out, v.Elem(i), params)
+			var pre *forkableWriter
+			pre, out = out.fork()
+			err = marshalField(pre, v.Elem(i), params)
 			if err != nil {
 				return
 			}
@@ -340,6 +404,25 @@ func marshalBody(out *forkableWriter, value reflect.Value, params fieldParameter
 }
 
 func marshalField(out *forkableWriter, v reflect.Value, params fieldParameters) (err os.Error) {
+	// If the field is an interface{} then recurse into it.
+	if v, ok := v.(*reflect.InterfaceValue); ok && v.Type().(*reflect.InterfaceType).NumMethod() == 0 {
+		return marshalField(out, v.Elem(), params)
+	}
+
+	if v.Type() == rawValueType {
+		rv := v.Interface().(RawValue)
+		err = marshalTagAndLength(out, tagAndLength{rv.Class, rv.Tag, len(rv.Bytes), rv.IsCompound})
+		if err != nil {
+			return
+		}
+		_, err = out.Write(rv.Bytes)
+		return
+	}
+
+	if params.optional && reflect.DeepEqual(v.Interface(), reflect.MakeZero(v.Type()).Interface()) {
+		return
+	}
+
 	tag, isCompound, ok := getUniversalType(v.Type())
 	if !ok {
 		err = StructuralError{fmt.Sprintf("unknown Go type: %v", v.Type())}
@@ -354,6 +437,13 @@ func marshalField(out *forkableWriter, v reflect.Value, params fieldParameters)
 		tag = params.stringType
 	}
 
+	if params.set {
+		if tag != tagSequence {
+			return StructuralError{"Non sequence tagged as set"}
+		}
+		tag = tagSet
+	}
+
 	tags, body := out.fork()
 
 	err = marshalBody(body, v, params)
@@ -403,3 +493,13 @@ func Marshal(out io.Writer, val interface{}) os.Error {
 	_, err = f.writeTo(out)
 	return err
 }
+
+// MarshalToMemory performs the same actions as Marshal, but returns the result
+// as a byte slice.
+func MarshalToMemory(val interface{}) ([]byte, os.Error) {
+	var out bytes.Buffer
+	if err := Marshal(&out, val); err != nil {
+		return nil, err
+	}
+	return out.Bytes(), nil
+}
diff --git a/src/pkg/asn1/marshal_test.go b/src/pkg/asn1/marshal_test.go
index da4a03c04..8050031a7 100644
--- a/src/pkg/asn1/marshal_test.go
+++ b/src/pkg/asn1/marshal_test.go
@@ -24,9 +24,9 @@ type nestedStruct struct {
 	A intStruct
 }
 
-type marshalTest struct {
-	in  interface{}
-	out string // hex encoded
+type rawContentsStruct struct {
+	Raw RawContent
+	A   int
 }
 
 type implicitTagTest struct {
@@ -45,11 +45,18 @@ type printableStringTest struct {
 	A string "printable"
 }
 
+type testSET []int
+
 func setPST(t *time.Time) *time.Time {
 	t.ZoneOffset = -28800
 	return t
 }
 
+type marshalTest struct {
+	in  interface{}
+	out string // hex encoded
+}
+
 var marshalTests = []marshalTest{
 	marshalTest{10, "02010a"},
 	marshalTest{intStruct{64}, "3003020140"},
@@ -64,9 +71,14 @@ var marshalTests = []marshalTest{
 	marshalTest{BitString{[]byte{0x80}, 1}, "03020780"},
 	marshalTest{BitString{[]byte{0x81, 0xf0}, 12}, "03030481f0"},
 	marshalTest{ObjectIdentifier([]int{1, 2, 3, 4}), "06032a0304"},
+	marshalTest{ObjectIdentifier([]int{1, 2, 840, 133549, 1, 1, 5}), "06092a864888932d010105"},
 	marshalTest{"test", "130474657374"},
 	marshalTest{ia5StringTest{"test"}, "3006160474657374"},
 	marshalTest{printableStringTest{"test"}, "3006130474657374"},
+	marshalTest{rawContentsStruct{nil, 64}, "3003020140"},
+	marshalTest{rawContentsStruct{[]byte{0x30, 3, 1, 2, 3}, 64}, "3003010203"},
+	marshalTest{RawValue{Tag: 1, Class: 2, IsCompound: false, Bytes: []byte{1, 2, 3}}, "8103010203"},
+	marshalTest{testSET([]int{10}), "310302010a"},
 }
 
 func TestMarshal(t *testing.T) {