Expose Reader and Writer from JSPB.

Interfaces are still WIP

jspb/constants.go

@@ -0,0 +1,6 @@
+package jspb
+
+const (
+	// InvalidFieldNumber is a Flag to indicate a missing field.
+	InvalidFieldNumber = -1
+)

jspb/errors.go

@@ -0,0 +1,19 @@
+package jspb
+
+import "github.com/gopherjs/gopherjs/js"
+
+// catchException recovers any JS exceptions and
+// stores the error in the parameter
+func catchException(err *error) {
+	e := recover()
+
+	if e == nil {
+		return
+	}
+
+	if e, ok := e.(*js.Error); ok {
+		*err = e
+	} else {
+		panic(e)
+	}
+}

jspb/reader.go

@@ -0,0 +1,120 @@
+package jspb
+
+import "github.com/gopherjs/gopherjs/js"
+
+// Reader encapsulates the jspb.BinaryReader
+type Reader interface {
+	Next() bool
+	Err() error
+
+	GetFieldNumber() int
+	SkipField()
+
+	// Scalars
+	ReadInt32() int32
+	ReadUint32() uint32
+	ReadString() string
+	ReadBool() bool
+
+	// Slices
+	ReadUint32Slice() []uint32
+
+	// Specials
+	ReadMessage(func())
+	ReadEnum() int
+}
+
+// NewReader returns a new Reader ready for writing
+func NewReader(data []byte) Reader {
+	return &reader{
+		Object: js.Global.Get("BinaryReader").New(data),
+	}
+}
+
+// reader implements the Reader interface
+type reader struct {
+	*js.Object
+	err error
+}
+
+// Reads the next field header in the stream if there is one, returns true if
+// we saw a valid field header or false if we've read the whole stream.
+// Sets err if we encountered a deprecated START_GROUP/END_GROUP field.
+func (r *reader) Next() bool {
+	defer catchException(&r.err)
+	return r.err == nil && r.Call("nextField").Bool() && !r.Call("isEndGroup").Bool()
+}
+
+// Err returns the error state of the Reader.
+func (r reader) Err() error {
+	return r.err
+}
+
+// The field number of the next field in the buffer, or
+// InvalidFieldNumber if there is no next field.
+func (r reader) GetFieldNumber() int {
+	return r.Call("getFieldNumber").Int()
+}
+
+// Skips over the next field in the binary stream.
+func (r reader) SkipField() {
+	r.Call("skipField")
+}
+
+// ReadInt32 reads a signed 32-bit integer field from the binary
+// stream, sets err if the next field in the
+// stream is not of the correct wire type.
+func (r *reader) ReadInt32() int32 {
+	defer catchException(&r.err)
+	return int32(r.Call("readInt32").Int())
+}
+
+// ReadUit32 reads an unsigned 32-bit integer field from the binary
+// stream, sets err if the next field in the
+// stream is not of the correct wire type.
+func (r *reader) ReadUint32() uint32 {
+	defer catchException(&r.err)
+	return uint32(r.Call("readUint32").Int())
+}
+
+// ReadString reads a string field from the binary stream, sets err
+// if the next field in the stream is not of the correct wire type.
+func (r *reader) ReadString() string {
+	defer catchException(&r.err)
+	return r.Call("readString").String()
+}
+
+// ReadBool reads a bool field from the binary stream, sets err
+// if the next field in the stream is not of the correct wire type.
+func (r *reader) ReadBool() bool {
+	defer catchException(&r.err)
+	return r.Call("readBool").Bool()
+}
+
+// ReadUint32Slice reads a packed 32-bit unsigned integer field
+// from the binary stream, sets err if the next field
+// in the stream is not of the correct wire type.
+func (r *reader) ReadUint32Slice() (ret []uint32) {
+	defer catchException(&r.err)
+	values := r.Call("readPackedUint32").Interface().([]interface{})
+	for _, value := range values {
+		ret = append(ret, uint32(value.(float64)))
+	}
+
+	return ret
+}
+
+// ReadMessage deserializes a proto using
+// the provided reader function.
+func (r *reader) ReadMessage(readFunc func()) {
+	defer catchException(&r.err)
+	r.Call("readMessage", js.Undefined /* Unused */, readFunc)
+}
+
+// ReadEnum reads an enum field from the binary stream,
+// sets err if the next field in the stream
+// is not of the correct wire type.
+func (r *reader) ReadEnum() int {
+	defer catchException(&r.err)
+	return r.Call("readEnum").Int()
+}

jspb/writer.go

@@ -0,0 +1,73 @@
+package jspb
+
+import "github.com/gopherjs/gopherjs/js"
+
+// Writer encapsulates the jspb.BinaryWriter.
+type Writer interface {
+	GetResult() []byte
+
+	// Scalars
+	WriteInt32(int, int32)
+	WriteUint32(int, uint32)
+	WriteString(int, string)
+	WriteBool(int, bool)
+
+	// Slices
+	WriteUint32Slice(int, []uint32)
+
+	// Specials
+	WriteMessage(int, func())
+	WriteEnum(int, int)
+}
+
+// NewWriter returns a new Writer ready for writing.
+func NewWriter() Writer {
+	return &writer{
+		Object: js.Global.Get("BinaryWriter").New(),
+	}
+}
+
+// writer implements the Writer interface.
+type writer struct {
+	*js.Object
+}
+
+// GetResult returns the contents of the buffer as a byte slice.
+func (w writer) GetResult() []byte {
+	return w.Call("getResultBuffer").Interface().([]byte)
+}
+
+// WriteInt32 writes an int32 field to the buffer.
+func (w writer) WriteInt32(field int, value int32) {
+	w.Call("writeInt32", field, value)
+}
+
+// WriteInt32 writes a uint32 field to the buffer.
+func (w writer) WriteUint32(field int, value uint32) {
+	w.Call("writeUint32", field, value)
+}
+
+// WriteString writes a string field to the buffer
+func (w writer) WriteString(field int, value string) {
+	w.Call("writeString", field, value)
+}
+
+// WriteBool writes a string field to the buffer
+func (w writer) WriteBool(field int, value bool) {
+	w.Call("writeBool", field, value)
+}
+
+// WriteUint32Slice writes a uint32 slice field to the buffer
+func (w writer) WriteUint32Slice(field int, value []uint32) {
+	w.Call("writePackedUint32", field, value)
+}
+
+// WriteMessage writes a message to the buffer using writeFunc
+func (w writer) WriteMessage(field int, writeFunc func()) {
+	w.Call("writeMessage", field, 0 /* Unused */, writeFunc)
+}
+
+// WriteEnum writes an enum (as an int) to the buffer
+func (w writer) WriteEnum(field int, value int) {
+	w.Call("writeEnum", field, value)
+}