multi: Use NewXXXMessage(nil) where possible

This commit changes all occurrences of
NewMessage(NewSingleSegmentArena(nil)) to NewSingleSegmentArena(nil) and
all occurrences of NewMessage(NewMultiSegmentArena(nil)) to
NewMultiSegmentArena(nil).

Also, occurrences of Message{Arena: XXX} (where XXX is either a single
or multi segment arena) are changed when possible as well.

In the future, this will allow protecting Message values from wrong
usage by enforcing the use of NewMessage to initialize message objects
(instead of use of zero valued messages).

answer_test.go

@@ -59,7 +59,7 @@ func TestPromiseFulfill(t *testing.T) {
 	t.Run("Done", func(t *testing.T) {
 		p := NewPromise(dummyMethod, dummyPipelineCaller{}, nil)
 		done := p.Answer().Done()
-		msg, seg, _ := NewMessage(SingleSegment(nil))
+		msg, seg := NewSingleSegmentMessage(nil)
 		defer msg.Release()
 
 		res, _ := NewStruct(seg, ObjectSize{DataSize: 8})
@@ -75,7 +75,7 @@ func TestPromiseFulfill(t *testing.T) {
 		p := NewPromise(dummyMethod, dummyPipelineCaller{}, nil)
 		defer p.ReleaseClients()
 		ans := p.Answer()
-		msg, seg, _ := NewMessage(SingleSegment(nil))
+		msg, seg := NewSingleSegmentMessage(nil)
 		defer msg.Release()
 
 		res, _ := NewStruct(seg, ObjectSize{DataSize: 8})
@@ -99,7 +99,7 @@ func TestPromiseFulfill(t *testing.T) {
 		h := new(dummyHook)
 		c := NewClient(h)
 		defer c.Release()
-		msg, seg, _ := NewMessage(SingleSegment(nil))
+		msg, seg := NewSingleSegmentMessage(nil)
 		defer msg.Release()
 
 		res, _ := NewStruct(seg, ObjectSize{PointerCount: 3})

canonical.go

@@ -10,7 +10,7 @@ import (
 // for equivalent structs, even as the schema evolves.  The blob is
 // suitable for hashing or signing.
 func Canonicalize(s Struct) ([]byte, error) {
-	msg, seg, _ := NewMessage(SingleSegment(nil))
+	msg, seg := NewSingleSegmentMessage(nil)
 	if !s.IsValid() {
 		return seg.Data(), nil
 	}

canonical_test.go

@@ -19,23 +19,23 @@ func TestCanonicalize(t *testing.T) {
 	}, {
 		name: "empty struct",
 		f: func() Struct {
-			_, seg, _ := NewMessage(SingleSegment(nil))
+			_, seg := NewSingleSegmentMessage(nil)
 			s, _ := NewStruct(seg, ObjectSize{})
 			return s
 		},
 		want: []byte{0xfc, 0xff, 0xff, 0xff, 0, 0, 0, 0},
 	}, {
 		name: "zero data, zero pointer struct",
 		f: func() Struct {
-			_, seg, _ := NewMessage(SingleSegment(nil))
+			_, seg := NewSingleSegmentMessage(nil)
 			s, _ := NewStruct(seg, ObjectSize{DataSize: 8, PointerCount: 1})
 			return s
 		},
 		want: []byte{0xfc, 0xff, 0xff, 0xff, 0, 0, 0, 0},
 	}, {
 		name: "one word data struct",
 		f: func() Struct {
-			_, seg, _ := NewMessage(SingleSegment(nil))
+			_, seg := NewSingleSegmentMessage(nil)
 			s, _ := NewStruct(seg, ObjectSize{DataSize: 8, PointerCount: 1})
 			s.SetUint16(0, 0xbeef)
 			return s
@@ -47,7 +47,7 @@ func TestCanonicalize(t *testing.T) {
 	}, {
 		name: "two pointers to zero structs",
 		f: func() Struct {
-			_, seg, _ := NewMessage(SingleSegment(nil))
+			_, seg := NewSingleSegmentMessage(nil)
 			s, _ := NewStruct(seg, ObjectSize{PointerCount: 2})
 			e1, _ := NewStruct(seg, ObjectSize{DataSize: 8})
 			e2, _ := NewStruct(seg, ObjectSize{DataSize: 8})
@@ -63,7 +63,7 @@ func TestCanonicalize(t *testing.T) {
 	}, {
 		name: "pointer to interface",
 		f: func() Struct {
-			_, seg, _ := NewMessage(SingleSegment(nil))
+			_, seg := NewSingleSegmentMessage(nil)
 			s, _ := NewStruct(seg, ObjectSize{PointerCount: 2})
 			iface := NewInterface(seg, 1)
 			s.SetPtr(0, iface.ToPtr())
@@ -76,7 +76,7 @@ func TestCanonicalize(t *testing.T) {
 	}, {
 		name: "int list",
 		f: func() Struct {
-			_, seg, _ := NewMessage(SingleSegment(nil))
+			_, seg := NewSingleSegmentMessage(nil)
 			s, _ := NewStruct(seg, ObjectSize{PointerCount: 1})
 			l, _ := NewInt8List(seg, 5)
 			s.SetPtr(0, l.ToPtr())
@@ -95,7 +95,7 @@ func TestCanonicalize(t *testing.T) {
 	}, {
 		name: "zero int list",
 		f: func() Struct {
-			_, seg, _ := NewMessage(SingleSegment(nil))
+			_, seg := NewSingleSegmentMessage(nil)
 			s, _ := NewStruct(seg, ObjectSize{PointerCount: 1})
 			l, _ := NewInt8List(seg, 5)
 			s.SetPtr(0, l.ToPtr())
@@ -110,7 +110,7 @@ func TestCanonicalize(t *testing.T) {
 	}, {
 		name: "struct list",
 		f: func() Struct {
-			_, seg, _ := NewMessage(SingleSegment(nil))
+			_, seg := NewSingleSegmentMessage(nil)
 			s, _ := NewStruct(seg, ObjectSize{PointerCount: 1})
 			l, _ := NewCompositeList(seg, ObjectSize{DataSize: 8, PointerCount: 1}, 2)
 			s.SetPtr(0, l.ToPtr())
@@ -133,7 +133,7 @@ func TestCanonicalize(t *testing.T) {
 	}, {
 		name: "zero struct list",
 		f: func() Struct {
-			_, seg, _ := NewMessage(SingleSegment(nil))
+			_, seg := NewSingleSegmentMessage(nil)
 			s, _ := NewStruct(seg, ObjectSize{PointerCount: 1})
 			l, _ := NewCompositeList(seg, ObjectSize{DataSize: 16, PointerCount: 2}, 3)
 			s.SetPtr(0, l.ToPtr())
@@ -148,7 +148,7 @@ func TestCanonicalize(t *testing.T) {
 	}, {
 		name: "zero-length struct list",
 		f: func() Struct {
-			_, seg, _ := NewMessage(SingleSegment(nil))
+			_, seg := NewSingleSegmentMessage(nil)
 			s, _ := NewStruct(seg, ObjectSize{PointerCount: 1})
 			l, _ := NewCompositeList(seg, ObjectSize{DataSize: 16, PointerCount: 2}, 0)
 			s.SetPtr(0, l.ToPtr())

capability_test.go

@@ -357,10 +357,8 @@ func (dr *dummyReturner) AllocResults(sz ObjectSize) (Struct, error) {
 	if dr.s.IsValid() {
 		return Struct{}, errors.New("AllocResults called multiple times")
 	}
-	_, seg, err := NewMessage(SingleSegment(nil))
-	if err != nil {
-		return Struct{}, err
-	}
+	_, seg := NewSingleSegmentMessage(nil)
+	var err error
 	dr.s, err = NewRootStruct(seg, sz)
 	return dr.s, err
 }
@@ -377,10 +375,7 @@ func (dr *dummyReturner) ReleaseResults() {
 }
 
 func TestToInterface(t *testing.T) {
-	_, seg, err := NewMessage(SingleSegment(nil))
-	if err != nil {
-		t.Fatal(err)
-	}
+	_, seg := NewSingleSegmentMessage(nil)
 	tests := []struct {
 		ptr Ptr
 		in  Interface
@@ -399,10 +394,7 @@ func TestToInterface(t *testing.T) {
 }
 
 func TestInterface_value(t *testing.T) {
-	_, seg, err := NewMessage(SingleSegment(nil))
-	if err != nil {
-		t.Fatal(err)
-	}
+	_, seg := NewSingleSegmentMessage(nil)
 	tests := []struct {
 		in  Interface
 		val rawPointer
@@ -421,10 +413,7 @@ func TestInterface_value(t *testing.T) {
 }
 
 func TestTransform(t *testing.T) {
-	_, s, err := NewMessage(SingleSegment(nil))
-	if err != nil {
-		t.Fatal(err)
-	}
+	_, s := NewSingleSegmentMessage(nil)
 	root, err := NewStruct(s, ObjectSize{PointerCount: 2})
 	if err != nil {
 		t.Fatal(err)
@@ -442,7 +431,7 @@ func TestTransform(t *testing.T) {
 	b.SetUint64(0, 2)
 	a.SetPtr(0, b.ToPtr())
 
-	dmsg, d, err := NewMessage(SingleSegment(nil))
+	dmsg, d := NewSingleSegmentMessage(nil)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -675,20 +664,17 @@ func deepPointerEqual(a, b Ptr) bool {
 	if !a.IsValid() || !b.IsValid() {
 		return false
 	}
-	msgA, _, _ := NewMessage(SingleSegment(nil))
+	msgA, _ := NewSingleSegmentMessage(nil)
 	msgA.SetRoot(a)
 	abytes, _ := msgA.Marshal()
-	msgB, _, _ := NewMessage(SingleSegment(nil))
+	msgB, _ := NewSingleSegmentMessage(nil)
 	msgB.SetRoot(b)
 	bbytes, _ := msgB.Marshal()
 	return bytes.Equal(abytes, bbytes)
 }
 
 func newEmptyStruct() Struct {
-	_, seg, err := NewMessage(SingleSegment(nil))
-	if err != nil {
-		panic(err)
-	}
+	_, seg := NewSingleSegmentMessage(nil)
 	s, err := NewRootStruct(seg, ObjectSize{})
 	if err != nil {
 		panic(err)

capnpc-go/capnpc-go.go

@@ -168,7 +168,7 @@ func (g *generator) defineSchemaVar() error {
 	}
 	sort.Sort(uint64Slice(ids))
 
-	msg, seg, _ := capnp.NewMessage(capnp.SingleSegment(nil))
+	msg, seg := capnp.NewSingleSegmentMessage(nil)
 	req, _ := schema.NewRootCodeGeneratorRequest(seg)
 	// TODO(light): find largest object size and use that to allocate list
 	nodes, _ := req.NewNodes(int32(len(g.nodes)))

capnpc-go/fileparts.go

@@ -38,11 +38,8 @@ func (sd *staticData) init(fileID uint64) {
 }
 
 func (sd *staticData) copyData(obj capnp.Ptr) (staticDataRef, error) {
-	m, _, err := capnp.NewMessage(capnp.SingleSegment(nil))
-	if err != nil {
-		return staticDataRef{}, err
-	}
-	err = m.SetRoot(obj)
+	m, _ := capnp.NewSingleSegmentMessage(nil)
+	err := m.SetRoot(obj)
 	if err != nil {
 		return staticDataRef{}, err
 	}

encoding/text/marshal.go

@@ -74,7 +74,7 @@ func (enc *Encoder) Encode(typeID uint64, s capnp.Struct) error {
 
 // EncodeList writes the text representation of struct list l to the stream.
 func (enc *Encoder) EncodeList(typeID uint64, l capnp.List) error {
-	_, seg, _ := capnp.NewMessage(capnp.SingleSegment(nil))
+	_, seg := capnp.NewSingleSegmentMessage(nil)
 	typ, _ := schema.NewRootType(seg)
 	typ.SetStructType()
 	typ.StructType().SetTypeId(typeID)

example/books/ex1/books1.go

@@ -9,10 +9,7 @@ import (
 
 func main() {
 	// Make a brand new empty message.  A Message allocates Cap'n Proto structs.
-	msg, seg, err := capnp.NewMessage(capnp.SingleSegment(nil))
-	if err != nil {
-		panic(err)
-	}
+	msg, seg := capnp.NewSingleSegmentMessage(nil)
 
 	// Create a new Book struct.  Every message must have a root struct.
 	book, err := books.NewRootBook(seg)

example_test.go

@@ -10,10 +10,7 @@ import (
 
 func Example() {
 	// Make a brand new empty message.
-	msg, seg, err := capnp.NewMessage(capnp.SingleSegment(nil))
-	if err != nil {
-		panic(err)
-	}
+	msg, seg := capnp.NewSingleSegmentMessage(nil)
 
 	// If you want runtime-type identification, this is easily obtained. Just
 	// wrap everything in a struct that contains a single anoymous union (e.g. struct Z).
@@ -87,11 +84,7 @@ func Example() {
 }
 
 func ExampleUnmarshal() {
-	msg, s, err := capnp.NewMessage(capnp.SingleSegment(nil))
-	if err != nil {
-		fmt.Printf("allocation error %v\n", err)
-		return
-	}
+	msg, s := capnp.NewSingleSegmentMessage(nil)
 	d, err := air.NewRootZdate(s)
 	if err != nil {
 		fmt.Printf("root error %v\n", err)