Support proto3.

18 files changed, 724 insertions, 25 deletions

diff --git a/Makefile b/Makefile
index 291de7d..7d2df79 100644
--- a/Makefile
+++ b/Makefile
@@ -50,3 +50,4 @@ regenerate:
 	make -C protoc-gen-go/descriptor regenerate
 	make -C protoc-gen-go/plugin regenerate
 	make -C proto/testdata regenerate
+	make -C proto/proto3_proto regenerate
diff --git a/proto/Makefile b/proto/Makefile
index 66bd2f2..fb838ed 100644
--- a/proto/Makefile
+++ b/proto/Makefile
@@ -37,4 +37,7 @@ test: install generate-test-pbs
 
 
 generate-test-pbs:
-	make install && cd testdata && make
+	make install
+	make -C testdata
+	make -C proto3_proto
+	make
diff --git a/proto/decode.go b/proto/decode.go
index 6a09e29..6166dd4 100644
--- a/proto/decode.go
+++ b/proto/decode.go
@@ -465,6 +465,15 @@ func (o *Buffer) dec_bool(p *Properties, base structPointer) error {
 	return nil
 }
 
+func (o *Buffer) dec_proto3_bool(p *Properties, base structPointer) error {
+	u, err := p.valDec(o)
+	if err != nil {
+		return err
+	}
+	*structPointer_BoolVal(base, p.field) = u != 0
+	return nil
+}
+
 // Decode an int32.
 func (o *Buffer) dec_int32(p *Properties, base structPointer) error {
 	u, err := p.valDec(o)
@@ -475,6 +484,15 @@ func (o *Buffer) dec_int32(p *Properties, base structPointer) error {
 	return nil
 }
 
+func (o *Buffer) dec_proto3_int32(p *Properties, base structPointer) error {
+	u, err := p.valDec(o)
+	if err != nil {
+		return err
+	}
+	word32Val_Set(structPointer_Word32Val(base, p.field), uint32(u))
+	return nil
+}
+
 // Decode an int64.
 func (o *Buffer) dec_int64(p *Properties, base structPointer) error {
 	u, err := p.valDec(o)
@@ -485,6 +503,15 @@ func (o *Buffer) dec_int64(p *Properties, base structPointer) error {
 	return nil
 }
 
+func (o *Buffer) dec_proto3_int64(p *Properties, base structPointer) error {
+	u, err := p.valDec(o)
+	if err != nil {
+		return err
+	}
+	word64Val_Set(structPointer_Word64Val(base, p.field), o, u)
+	return nil
+}
+
 // Decode a string.
 func (o *Buffer) dec_string(p *Properties, base structPointer) error {
 	s, err := o.DecodeStringBytes()
@@ -497,6 +524,15 @@ func (o *Buffer) dec_string(p *Properties, base structPointer) error {
 	return nil
 }
 
+func (o *Buffer) dec_proto3_string(p *Properties, base structPointer) error {
+	s, err := o.DecodeStringBytes()
+	if err != nil {
+		return err
+	}
+	*structPointer_StringVal(base, p.field) = s
+	return nil
+}
+
 // Decode a slice of bytes ([]byte).
 func (o *Buffer) dec_slice_byte(p *Properties, base structPointer) error {
 	b, err := o.DecodeRawBytes(true)
diff --git a/proto/encode.go b/proto/encode.go
index cbe4242..cc202cd 100644
--- a/proto/encode.go
+++ b/proto/encode.go
@@ -298,6 +298,16 @@ func (o *Buffer) enc_bool(p *Properties, base structPointer) error {
 	return nil
 }
 
+func (o *Buffer) enc_proto3_bool(p *Properties, base structPointer) error {
+	v := *structPointer_BoolVal(base, p.field)
+	if !v {
+		return ErrNil
+	}
+	o.buf = append(o.buf, p.tagcode...)
+	p.valEnc(o, 1)
+	return nil
+}
+
 func size_bool(p *Properties, base structPointer) int {
 	v := *structPointer_Bool(base, p.field)
 	if v == nil {
@@ -306,6 +316,14 @@ func size_bool(p *Properties, base structPointer) int {
 	return len(p.tagcode) + 1 // each bool takes exactly one byte
 }
 
+func size_proto3_bool(p *Properties, base structPointer) int {
+	v := *structPointer_BoolVal(base, p.field)
+	if !v {
+		return 0
+	}
+	return len(p.tagcode) + 1 // each bool takes exactly one byte
+}
+
 // Encode an int32.
 func (o *Buffer) enc_int32(p *Properties, base structPointer) error {
 	v := structPointer_Word32(base, p.field)
@@ -318,6 +336,17 @@ func (o *Buffer) enc_int32(p *Properties, base structPointer) error {
 	return nil
 }
 
+func (o *Buffer) enc_proto3_int32(p *Properties, base structPointer) error {
+	v := structPointer_Word32Val(base, p.field)
+	x := int32(word32Val_Get(v)) // permit sign extension to use full 64-bit range
+	if x == 0 {
+		return ErrNil
+	}
+	o.buf = append(o.buf, p.tagcode...)
+	p.valEnc(o, uint64(x))
+	return nil
+}
+
 func size_int32(p *Properties, base structPointer) (n int) {
 	v := structPointer_Word32(base, p.field)
 	if word32_IsNil(v) {
@@ -329,6 +358,17 @@ func size_int32(p *Properties, base structPointer) (n int) {
 	return
 }
 
+func size_proto3_int32(p *Properties, base structPointer) (n int) {
+	v := structPointer_Word32Val(base, p.field)
+	x := int32(word32Val_Get(v)) // permit sign extension to use full 64-bit range
+	if x == 0 {
+		return 0
+	}
+	n += len(p.tagcode)
+	n += p.valSize(uint64(x))
+	return
+}
+
 // Encode a uint32.
 // Exactly the same as int32, except for no sign extension.
 func (o *Buffer) enc_uint32(p *Properties, base structPointer) error {
@@ -342,6 +382,17 @@ func (o *Buffer) enc_uint32(p *Properties, base structPointer) error {
 	return nil
 }
 
+func (o *Buffer) enc_proto3_uint32(p *Properties, base structPointer) error {
+	v := structPointer_Word32Val(base, p.field)
+	x := word32Val_Get(v)
+	if x == 0 {
+		return ErrNil
+	}
+	o.buf = append(o.buf, p.tagcode...)
+	p.valEnc(o, uint64(x))
+	return nil
+}
+
 func size_uint32(p *Properties, base structPointer) (n int) {
 	v := structPointer_Word32(base, p.field)
 	if word32_IsNil(v) {
@@ -353,6 +404,17 @@ func size_uint32(p *Properties, base structPointer) (n int) {
 	return
 }
 
+func size_proto3_uint32(p *Properties, base structPointer) (n int) {
+	v := structPointer_Word32Val(base, p.field)
+	x := word32Val_Get(v)
+	if x == 0 {
+		return 0
+	}
+	n += len(p.tagcode)
+	n += p.valSize(uint64(x))
+	return
+}
+
 // Encode an int64.
 func (o *Buffer) enc_int64(p *Properties, base structPointer) error {
 	v := structPointer_Word64(base, p.field)
@@ -365,6 +427,17 @@ func (o *Buffer) enc_int64(p *Properties, base structPointer) error {
 	return nil
 }
 
+func (o *Buffer) enc_proto3_int64(p *Properties, base structPointer) error {
+	v := structPointer_Word64Val(base, p.field)
+	x := word64Val_Get(v)
+	if x == 0 {
+		return ErrNil
+	}
+	o.buf = append(o.buf, p.tagcode...)
+	p.valEnc(o, x)
+	return nil
+}
+
 func size_int64(p *Properties, base structPointer) (n int) {
 	v := structPointer_Word64(base, p.field)
 	if word64_IsNil(v) {
@@ -376,6 +449,17 @@ func size_int64(p *Properties, base structPointer) (n int) {
 	return
 }
 
+func size_proto3_int64(p *Properties, base structPointer) (n int) {
+	v := structPointer_Word64Val(base, p.field)
+	x := word64Val_Get(v)
+	if x == 0 {
+		return 0
+	}
+	n += len(p.tagcode)
+	n += p.valSize(x)
+	return
+}
+
 // Encode a string.
 func (o *Buffer) enc_string(p *Properties, base structPointer) error {
 	v := *structPointer_String(base, p.field)
@@ -388,6 +472,16 @@ func (o *Buffer) enc_string(p *Properties, base structPointer) error {
 	return nil
 }
 
+func (o *Buffer) enc_proto3_string(p *Properties, base structPointer) error {
+	v := *structPointer_StringVal(base, p.field)
+	if v == "" {
+		return ErrNil
+	}
+	o.buf = append(o.buf, p.tagcode...)
+	o.EncodeStringBytes(v)
+	return nil
+}
+
 func size_string(p *Properties, base structPointer) (n int) {
 	v := *structPointer_String(base, p.field)
 	if v == nil {
@@ -399,6 +493,16 @@ func size_string(p *Properties, base structPointer) (n int) {
 	return
 }
 
+func size_proto3_string(p *Properties, base structPointer) (n int) {
+	v := *structPointer_StringVal(base, p.field)
+	if v == "" {
+		return 0
+	}
+	n += len(p.tagcode)
+	n += sizeStringBytes(v)
+	return
+}
+
 // All protocol buffer fields are nillable, but be careful.
 func isNil(v reflect.Value) bool {
 	switch v.Kind() {
@@ -551,6 +655,16 @@ func (o *Buffer) enc_slice_byte(p *Properties, base structPointer) error {
 	return nil
 }
 
+func (o *Buffer) enc_proto3_slice_byte(p *Properties, base structPointer) error {
+	s := *structPointer_Bytes(base, p.field)
+	if len(s) == 0 {
+		return ErrNil
+	}
+	o.buf = append(o.buf, p.tagcode...)
+	o.EncodeRawBytes(s)
+	return nil
+}
+
 func size_slice_byte(p *Properties, base structPointer) (n int) {
 	s := *structPointer_Bytes(base, p.field)
 	if s == nil {
@@ -561,6 +675,16 @@ func size_slice_byte(p *Properties, base structPointer) (n int) {
 	return
 }
 
+func size_proto3_slice_byte(p *Properties, base structPointer) (n int) {
+	s := *structPointer_Bytes(base, p.field)
+	if len(s) == 0 {
+		return 0
+	}
+	n += len(p.tagcode)
+	n += sizeRawBytes(s)
+	return
+}
+
 // Encode a slice of int32s ([]int32).
 func (o *Buffer) enc_slice_int32(p *Properties, base structPointer) error {
 	s := structPointer_Word32Slice(base, p.field)
diff --git a/proto/pointer_reflect.go b/proto/pointer_reflect.go
index 0c53417..42c387a 100644
--- a/proto/pointer_reflect.go
+++ b/proto/pointer_reflect.go
@@ -114,6 +114,11 @@ func structPointer_Bool(p structPointer, f field) **bool {
 	return structPointer_ifield(p, f).(**bool)
 }
 
+// BoolVal returns the address of a bool field in the struct.
+func structPointer_BoolVal(p structPointer, f field) *bool {
+	return structPointer_ifield(p, f).(*bool)
+}
+
 // BoolSlice returns the address of a []bool field in the struct.
 func structPointer_BoolSlice(p structPointer, f field) *[]bool {
 	return structPointer_ifield(p, f).(*[]bool)
@@ -124,6 +129,11 @@ func structPointer_String(p structPointer, f field) **string {
 	return structPointer_ifield(p, f).(**string)
 }
 
+// StringVal returns the address of a string field in the struct.
+func structPointer_StringVal(p structPointer, f field) *string {
+	return structPointer_ifield(p, f).(*string)
+}
+
 // StringSlice returns the address of a []string field in the struct.
 func structPointer_StringSlice(p structPointer, f field) *[]string {
 	return structPointer_ifield(p, f).(*[]string)
@@ -235,6 +245,49 @@ func structPointer_Word32(p structPointer, f field) word32 {
 	return word32{structPointer_field(p, f)}
 }
 
+// A word32Val represents a field of type int32, uint32, float32, or enum.
+// That is, v.Type() is int32, uint32, float32, or enum and v is assignable.
+type word32Val struct {
+	v reflect.Value
+}
+
+// Set sets *p to x.
+func word32Val_Set(p word32Val, x uint32) {
+	switch p.v.Type() {
+	case int32Type:
+		p.v.SetInt(int64(x))
+		return
+	case uint32Type:
+		p.v.SetUint(uint64(x))
+		return
+	case float32Type:
+		p.v.SetFloat(float64(math.Float32frombits(x)))
+		return
+	}
+
+	// must be enum
+	p.v.SetInt(int64(int32(x)))
+}
+
+// Get gets the bits pointed at by p, as a uint32.
+func word32Val_Get(p word32Val) uint32 {
+	elem := p.v
+	switch elem.Kind() {
+	case reflect.Int32:
+		return uint32(elem.Int())
+	case reflect.Uint32:
+		return uint32(elem.Uint())
+	case reflect.Float32:
+		return math.Float32bits(float32(elem.Float()))
+	}
+	panic("unreachable")
+}
+
+// Word32Val returns a reference to a int32, uint32, float32, or enum field in the struct.
+func structPointer_Word32Val(p structPointer, f field) word32Val {
+	return word32Val{structPointer_field(p, f)}
+}
+
 // A word32Slice is a slice of 32-bit values.
 // That is, v.Type() is []int32, []uint32, []float32, or []enum.
 type word32Slice struct {
@@ -339,6 +392,43 @@ func structPointer_Word64(p structPointer, f field) word64 {
 	return word64{structPointer_field(p, f)}
 }
 
+// word64Val is like word32Val but for 64-bit values.
+type word64Val struct {
+	v reflect.Value
+}
+
+func word64Val_Set(p word64Val, o *Buffer, x uint64) {
+	switch p.v.Type() {
+	case int64Type:
+		p.v.SetInt(int64(x))
+		return
+	case uint64Type:
+		p.v.SetUint(x)
+		return
+	case float64Type:
+		p.v.SetFloat(math.Float64frombits(x))
+		return
+	}
+	panic("unreachable")
+}
+
+func word64Val_Get(p word64Val) uint64 {
+	elem := p.v
+	switch elem.Kind() {
+	case reflect.Int64:
+		return uint64(elem.Int())
+	case reflect.Uint64:
+		return elem.Uint()
+	case reflect.Float64:
+		return math.Float64bits(elem.Float())
+	}
+	panic("unreachable")
+}
+
+func structPointer_Word64Val(p structPointer, f field) word64Val {
+	return word64Val{structPointer_field(p, f)}
+}
+
 type word64Slice struct {
 	v reflect.Value
 }
diff --git a/proto/pointer_unsafe.go b/proto/pointer_unsafe.go
index 7f3473e..cf9fc9a 100644
--- a/proto/pointer_unsafe.go
+++ b/proto/pointer_unsafe.go
@@ -100,6 +100,11 @@ func structPointer_Bool(p structPointer, f field) **bool {
 	return (**bool)(unsafe.Pointer(uintptr(p) + uintptr(f)))
 }
 
+// BoolVal returns the address of a bool field in the struct.
+func structPointer_BoolVal(p structPointer, f field) *bool {
+	return (*bool)(unsafe.Pointer(uintptr(p) + uintptr(f)))
+}
+
 // BoolSlice returns the address of a []bool field in the struct.
 func structPointer_BoolSlice(p structPointer, f field) *[]bool {
 	return (*[]bool)(unsafe.Pointer(uintptr(p) + uintptr(f)))
@@ -110,6 +115,11 @@ func structPointer_String(p structPointer, f field) **string {
 	return (**string)(unsafe.Pointer(uintptr(p) + uintptr(f)))
 }
 
+// StringVal returns the address of a string field in the struct.
+func structPointer_StringVal(p structPointer, f field) *string {
+	return (*string)(unsafe.Pointer(uintptr(p) + uintptr(f)))
+}
+
 // StringSlice returns the address of a []string field in the struct.
 func structPointer_StringSlice(p structPointer, f field) *[]string {
 	return (*[]string)(unsafe.Pointer(uintptr(p) + uintptr(f)))
@@ -170,6 +180,24 @@ func structPointer_Word32(p structPointer, f field) word32 {
 	return word32((**uint32)(unsafe.Pointer(uintptr(p) + uintptr(f))))
 }
 
+// A word32Val is the address of a 32-bit value field.
+type word32Val *uint32
+
+// Set sets *p to x.
+func word32Val_Set(p word32Val, x uint32) {
+	*p = x
+}
+
+// Get gets the value pointed at by p.
+func word32Val_Get(p word32Val) uint32 {
+	return *p
+}
+
+// Word32Val returns the address of a *int32, *uint32, *float32, or *enum field in the struct.
+func structPointer_Word32Val(p structPointer, f field) word32Val {
+	return word32Val((*uint32)(unsafe.Pointer(uintptr(p) + uintptr(f))))
+}
+
 // A word32Slice is a slice of 32-bit values.
 type word32Slice []uint32
 
@@ -206,6 +234,21 @@ func structPointer_Word64(p structPointer, f field) word64 {
 	return word64((**uint64)(unsafe.Pointer(uintptr(p) + uintptr(f))))
 }
 
+// word64Val is like word32Val but for 64-bit values.
+type word64Val *uint64
+
+func word64Val_Set(p word64Val, o *Buffer, x uint64) {
+	*p = x
+}
+
+func word64Val_Get(p word64Val) uint64 {
+	return *p
+}
+
+func structPointer_Word64Val(p structPointer, f field) word64Val {
+	return word64Val((*uint64)(unsafe.Pointer(uintptr(p) + uintptr(f))))
+}
+
 // word64Slice is like word32Slice but for 64-bit values.
 type word64Slice []uint64
 
diff --git a/proto/properties.go b/proto/properties.go
index 7262888..4420881 100644
--- a/proto/properties.go
+++ b/proto/properties.go
@@ -155,6 +155,7 @@ type Properties struct {
 	Repeated bool
 	Packed   bool   // relevant for repeated primitives only
 	Enum     string // set for enum types only
+	proto3   bool   // whether this is known to be a proto3 field; set for []byte only
 
 	Default    string // default value
 	HasDefault bool   // whether an explicit default was provided
@@ -200,6 +201,9 @@ func (p *Properties) String() string {
 	if p.OrigName != p.Name {
 		s += ",name=" + p.OrigName
 	}
+	if p.proto3 {
+		s += ",proto3"
+	}
 	if len(p.Enum) > 0 {
 		s += ",enum=" + p.Enum
 	}
@@ -274,6 +278,8 @@ func (p *Properties) Parse(s string) {
 			p.OrigName = f[5:]
 		case strings.HasPrefix(f, "enum="):
 			p.Enum = f[5:]
+		case f == "proto3":
+			p.proto3 = true
 		case strings.HasPrefix(f, "def="):
 			p.HasDefault = true
 			p.Default = f[4:] // rest of string
@@ -302,6 +308,37 @@ func (p *Properties) setEncAndDec(typ reflect.Type, lockGetProp bool) {
 	default:
 		fmt.Fprintf(os.Stderr, "proto: no coders for %v\n", t1)
 
+	// proto3 scalar types
+
+	case reflect.Bool:
+		p.enc = (*Buffer).enc_proto3_bool
+		p.dec = (*Buffer).dec_proto3_bool
+		p.size = size_proto3_bool
+	case reflect.Int32:
+		p.enc = (*Buffer).enc_proto3_int32
+		p.dec = (*Buffer).dec_proto3_int32
+		p.size = size_proto3_int32
+	case reflect.Uint32:
+		p.enc = (*Buffer).enc_proto3_uint32
+		p.dec = (*Buffer).dec_proto3_int32 // can reuse
+		p.size = size_proto3_uint32
+	case reflect.Int64, reflect.Uint64:
+		p.enc = (*Buffer).enc_proto3_int64
+		p.dec = (*Buffer).dec_proto3_int64
+		p.size = size_proto3_int64
+	case reflect.Float32:
+		p.enc = (*Buffer).enc_proto3_uint32 // can just treat them as bits
+		p.dec = (*Buffer).dec_proto3_int32
+		p.size = size_proto3_uint32
+	case reflect.Float64:
+		p.enc = (*Buffer).enc_proto3_int64 // can just treat them as bits
+		p.dec = (*Buffer).dec_proto3_int64
+		p.size = size_proto3_int64
+	case reflect.String:
+		p.enc = (*Buffer).enc_proto3_string
+		p.dec = (*Buffer).dec_proto3_string
+		p.size = size_proto3_string
+
 	case reflect.Ptr:
 		switch t2 := t1.Elem(); t2.Kind() {
 		default:
@@ -399,6 +436,10 @@ func (p *Properties) setEncAndDec(typ reflect.Type, lockGetProp bool) {
 			p.enc = (*Buffer).enc_slice_byte
 			p.dec = (*Buffer).dec_slice_byte
 			p.size = size_slice_byte
+			if p.proto3 {
+				p.enc = (*Buffer).enc_proto3_slice_byte
+				p.size = size_proto3_slice_byte
+			}
 		case reflect.Float32, reflect.Float64:
 			switch t2.Bits() {
 			case 32:
diff --git a/proto/proto3_proto/Makefile b/proto/proto3_proto/Makefile
new file mode 100644
index 0000000..75144b5
--- /dev/null
+++ b/proto/proto3_proto/Makefile
@@ -0,0 +1,44 @@
+# Go support for Protocol Buffers - Google's data interchange format
+#
+# Copyright 2014 The Go Authors.  All rights reserved.
+# https://github.com/golang/protobuf
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+include ../../Make.protobuf
+
+all:	regenerate
+
+regenerate:
+	rm -f proto3.pb.go
+	make proto3.pb.go
+
+# The following rules are just aids to development. Not needed for typical testing.
+
+diff:	regenerate
+	git diff proto3.pb.go
diff --git a/proto/proto3_proto/proto3.proto b/proto/proto3_proto/proto3.proto
new file mode 100644
index 0000000..3e327de
--- /dev/null
+++ b/proto/proto3_proto/proto3.proto
@@ -0,0 +1,58 @@
+// Go support for Protocol Buffers - Google's data interchange format
+//
+// Copyright 2014 The Go Authors.  All rights reserved.
+// https://github.com/golang/protobuf
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+syntax = "proto3";
+
+package proto3_proto;
+
+message Message {
+  enum Humour {
+    UNKNOWN = 0;
+    PUNS = 1;
+    SLAPSTICK = 2;
+    BILL_BAILEY = 3;
+  }
+
+  string name = 1;
+  Humour hilarity = 2;
+  uint32 height_in_cm = 3;
+  bytes data = 4;
+  int64 result_count = 7;
+  bool true_scotsman = 8;
+  float score = 9;
+
+  repeated uint64 key = 5;
+  Nested nested = 6;
+}
+
+message Nested {
+  string bunny = 1;
+}
diff --git a/proto/proto3_test.go b/proto/proto3_test.go
new file mode 100644
index 0000000..d4c96a9
--- /dev/null
+++ b/proto/proto3_test.go
@@ -0,0 +1,93 @@
+// Go support for Protocol Buffers - Google's data interchange format
+//
+// Copyright 2014 The Go Authors.  All rights reserved.
+// https://github.com/golang/protobuf
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+package proto_test
+
+import (
+	"testing"
+
+	pb "./proto3_proto"
+	"github.com/golang/protobuf/proto"
+)
+
+func TestProto3ZeroValues(t *testing.T) {
+	tests := []struct {
+		desc string
+		m    proto.Message
+	}{
+		{"zero message", &pb.Message{}},
+		{"empty bytes field", &pb.Message{Data: []byte{}}},
+	}
+	for _, test := range tests {
+		b, err := proto.Marshal(test.m)
+		if err != nil {
+			t.Errorf("%s: proto.Marshal: %v", test.desc, err)
+			continue
+		}
+		if len(b) > 0 {
+			t.Errorf("%s: Encoding is non-empty: %q", test.desc, b)
+		}
+	}
+}
+
+func TestRoundTripProto3(t *testing.T) {
+	m := &pb.Message{
+		Name:         "David",          // (2 | 1<<3): 0x0a 0x05 "David"
+		Hilarity:     pb.Message_PUNS,  // (0 | 2<<3): 0x10 0x01
+		HeightInCm:   178,              // (0 | 3<<3): 0x18 0xb2 0x01
+		Data:         []byte("roboto"), // (2 | 4<<3): 0x20 0x06 "roboto"
+		ResultCount:  47,               // (0 | 7<<3): 0x38 0x2f
+		TrueScotsman: true,             // (0 | 8<<3): 0x40 0x01
+		Score:        8.1,              // (5 | 9<<3): 0x4d <8.1>
+
+		Key: []uint64{1, 0xdeadbeef},
+		Nested: &pb.Nested{
+			Bunny: "Monty",
+		},
+	}
+	t.Logf(" m: %v", m)
+
+	b, err := proto.Marshal(m)
+	if err != nil {
+		t.Fatalf("proto.Marshal: %v", err)
+	}
+	t.Logf(" b: %q", b)
+
+	m2 := new(pb.Message)
+	if err := proto.Unmarshal(b, m2); err != nil {
+		t.Fatalf("proto.Unmarshal: %v", err)
+	}
+	t.Logf("m2: %v", m2)
+
+	if !proto.Equal(m, m2) {
+		t.Errorf("proto.Equal returned false:\n m: %v\nm2: %v", m, m2)
+	}
+}
diff --git a/proto/size_test.go b/proto/size_test.go
index 69d6481..4f87f3b 100644
--- a/proto/size_test.go
+++ b/proto/size_test.go
@@ -35,6 +35,7 @@ import (
 	"log"
 	"testing"
 
+	proto3pb "./proto3_proto"
 	pb "./testdata"
 	. "github.com/golang/protobuf/proto"
 )
@@ -102,6 +103,16 @@ var SizeTests = []struct {
 	{"unrecognized", &pb.MoreRepeated{XXX_unrecognized: []byte{13<<3 | 0, 4}}},
 	{"extension (unencoded)", messageWithExtension1},
 	{"extension (encoded)", messageWithExtension3},
+	// proto3 message
+	{"proto3 empty", &proto3pb.Message{}},
+	{"proto3 bool", &proto3pb.Message{TrueScotsman: true}},
+	{"proto3 int64", &proto3pb.Message{ResultCount: 1}},
+	{"proto3 uint32", &proto3pb.Message{HeightInCm: 123}},
+	{"proto3 float", &proto3pb.Message{Score: 12.6}},
+	{"proto3 string", &proto3pb.Message{Name: "Snezana"}},
+	{"proto3 bytes", &proto3pb.Message{Data: []byte("wowsa")}},
+	{"proto3 bytes, empty", &proto3pb.Message{Data: []byte{}}},
+	{"proto3 enum", &proto3pb.Message{Hilarity: proto3pb.Message_PUNS}},
 }
 
 func TestSize(t *testing.T) {
diff --git a/proto/testdata/Makefile b/proto/testdata/Makefile
index a4cd82a..fc28862 100644
--- a/proto/testdata/Makefile
+++ b/proto/testdata/Makefile
@@ -37,11 +37,11 @@ all:	regenerate
 regenerate:
 	rm -f test.pb.go
 	make test.pb.go
-	
+
 # The following rules are just aids to development. Not needed for typical testing.
 
 diff:	regenerate
-	hg diff test.pb.go
+	git diff test.pb.go
 
 restore:
 	cp test.pb.go.golden test.pb.go
diff --git a/proto/text.go b/proto/text.go
index 279c976..426db1e 100644
--- a/proto/text.go
+++ b/proto/text.go
@@ -244,6 +244,35 @@ func writeStruct(w *textWriter, sv reflect.Value) error {
 			}
 			continue
 		}
+		if props.proto3 && fv.Kind() == reflect.Slice && fv.Len() == 0 {
+			// empty bytes field
+			continue
+		}
+		if fv.Kind() != reflect.Ptr && fv.Kind() != reflect.Slice {
+			// proto3 non-repeated scalar field; skip if zero value
+			switch fv.Kind() {
+			case reflect.Bool:
+				if !fv.Bool() {
+					continue
+				}
+			case reflect.Int32, reflect.Int64:
+				if fv.Int() == 0 {
+					continue
+				}
+			case reflect.Uint32, reflect.Uint64:
+				if fv.Uint() == 0 {
+					continue
+				}
+			case reflect.Float32, reflect.Float64:
+				if fv.Float() == 0 {
+					continue
+				}
+			case reflect.String:
+				if fv.String() == "" {
+					continue
+				}
+			}
+		}
 
 		if err := writeName(w, props); err != nil {
 			return err
diff --git a/proto/text_parser.go b/proto/text_parser.go
index 4885bd7..f733f30 100644
--- a/proto/text_parser.go
+++ b/proto/text_parser.go
@@ -409,6 +409,10 @@ func (p *textParser) checkForColon(props *Properties, typ reflect.Type) *ParseEr
 				if typ.Elem().Kind() != reflect.Ptr {
 					break
 				}
+			} else if typ.Kind() == reflect.String {
+				// The proto3 exception is for a string field,
+				// which requires a colon.
+				break
 			}
 			needColon = false
 		}
diff --git a/proto/text_parser_test.go b/proto/text_parser_test.go
index b9268ee..89ab106 100644
--- a/proto/text_parser_test.go
+++ b/proto/text_parser_test.go
@@ -36,6 +36,7 @@ import (
 	"reflect"
 	"testing"
 
+	proto3pb "./proto3_proto"
 	. "./testdata"
 	. "github.com/golang/protobuf/proto"
 )
@@ -443,6 +444,21 @@ func TestRepeatedEnum(t *testing.T) {
 	}
 }
 
+func TestProto3TextParsing(t *testing.T) {
+	m := new(proto3pb.Message)
+	const in = `name: "Wallace" true_scotsman: true`
+	want := &proto3pb.Message{
+		Name:         "Wallace",
+		TrueScotsman: true,
+	}
+	if err := UnmarshalText(in, m); err != nil {
+		t.Fatal(err)
+	}
+	if !Equal(m, want) {
+		t.Errorf("\n got %v\nwant %v", m, want)
+	}
+}
+
 var benchInput string
 
 func init() {
diff --git a/proto/text_test.go b/proto/text_test.go
index 900ba6a..404920e 100644
--- a/proto/text_test.go
+++ b/proto/text_test.go
@@ -41,6 +41,7 @@ import (
 
 	"github.com/golang/protobuf/proto"
 
+	proto3pb "./proto3_proto"
 	pb "./testdata"
 )
 
@@ -406,3 +407,23 @@ Message <nil>
 		t.Errorf(" got: %s\nwant: %s", s, want)
 	}
 }
+
+func TestProto3Text(t *testing.T) {
+	tests := []struct {
+		m    proto.Message
+		want string
+	}{
+		// zero message
+		{&proto3pb.Message{}, ``},
+		// zero message except for an empty byte slice
+		{&proto3pb.Message{Data: []byte{}}, ``},
+		// trivial case
+		{&proto3pb.Message{Name: "Rob", HeightInCm: 175}, `name:"Rob" height_in_cm:175`},
+	}
+	for _, test := range tests {
+		got := strings.TrimSpace(test.m.String())
+		if got != test.want {
+			t.Errorf("\n got %s\nwant %s", got, test.want)
+		}
+	}
+}
diff --git a/protoc-gen-go/generator/generator.go b/protoc-gen-go/generator/generator.go
index 8882ed6..4b309cb 100644
--- a/protoc-gen-go/generator/generator.go
+++ b/protoc-gen-go/generator/generator.go
@@ -96,6 +96,12 @@ func (c *common) PackageName() string { return uniquePackageOf(c.file) }
 
 func (c *common) File() *descriptor.FileDescriptorProto { return c.file }
 
+func fileIsProto3(file *descriptor.FileDescriptorProto) bool {
+	return file.GetSyntax() == "proto3"
+}
+
+func (c *common) proto3() bool { return fileIsProto3(c.file) }
+
 // Descriptor represents a protocol buffer message.
 type Descriptor struct {
 	common
@@ -243,6 +249,7 @@ type FileDescriptor struct {
 
 	index int // The index of this file in the list of files to generate code for
 
+	proto3 bool // whether to generate proto3 code for this file
 }
 
 // PackageName is the package name we'll use in the generated code to refer to this file.
@@ -668,6 +675,7 @@ func (g *Generator) WrapTypes() {
 			ext:                 exts,
 			imp:                 imps,
 			exported:            make(map[Object][]symbol),
+			proto3:              fileIsProto3(f),
 		}
 		extractComments(fd)
 		g.allFiles[i] = fd
@@ -1116,7 +1124,9 @@ func (g *Generator) generateImports() {
 	// reference it later. The same argument applies to the math package,
 	// for handling bit patterns for floating-point numbers.
 	g.P("import " + g.Pkg["proto"] + " " + strconv.Quote(g.ImportPrefix+"github.com/golang/protobuf/proto"))
-	g.P("import " + g.Pkg["math"] + ` "math"`)
+	if !g.file.proto3 {
+		g.P("import " + g.Pkg["math"] + ` "math"`)
+	}
 	for i, s := range g.file.Dependency {
 		fd := g.fileByName(s)
 		// Do not import our own package.
@@ -1154,7 +1164,9 @@ func (g *Generator) generateImports() {
 	}
 	g.P("// Reference imports to suppress errors if they are not otherwise used.")
 	g.P("var _ = ", g.Pkg["proto"], ".Marshal")
-	g.P("var _ = ", g.Pkg["math"], ".Inf")
+	if !g.file.proto3 {
+		g.P("var _ = ", g.Pkg["math"], ".Inf")
+	}
 	g.P()
 }
 
@@ -1227,13 +1239,15 @@ func (g *Generator) generateEnum(enum *EnumDescriptor) {
 	g.Out()
 	g.P("}")
 
-	g.P("func (x ", ccTypeName, ") Enum() *", ccTypeName, " {")
-	g.In()
-	g.P("p := new(", ccTypeName, ")")
-	g.P("*p = x")
-	g.P("return p")
-	g.Out()
-	g.P("}")
+	if !enum.proto3() {
+		g.P("func (x ", ccTypeName, ") Enum() *", ccTypeName, " {")
+		g.In()
+		g.P("p := new(", ccTypeName, ")")
+		g.P("*p = x")
+		g.P("return p")
+		g.Out()
+		g.P("}")
+	}
 
 	g.P("func (x ", ccTypeName, ") String() string {")
 	g.In()
@@ -1241,18 +1255,20 @@ func (g *Generator) generateEnum(enum *EnumDescriptor) {
 	g.Out()
 	g.P("}")
 
-	g.P("func (x *", ccTypeName, ") UnmarshalJSON(data []byte) error {")
-	g.In()
-	g.P("value, err := ", g.Pkg["proto"], ".UnmarshalJSONEnum(", ccTypeName, `_value, data, "`, ccTypeName, `")`)
-	g.P("if err != nil {")
-	g.In()
-	g.P("return err")
-	g.Out()
-	g.P("}")
-	g.P("*x = ", ccTypeName, "(value)")
-	g.P("return nil")
-	g.Out()
-	g.P("}")
+	if !enum.proto3() {
+		g.P("func (x *", ccTypeName, ") UnmarshalJSON(data []byte) error {")
+		g.In()
+		g.P("value, err := ", g.Pkg["proto"], ".UnmarshalJSONEnum(", ccTypeName, `_value, data, "`, ccTypeName, `")`)
+		g.P("if err != nil {")
+		g.In()
+		g.P("return err")
+		g.Out()
+		g.P("}")
+		g.P("*x = ", ccTypeName, "(value)")
+		g.P("return nil")
+		g.Out()
+		g.P("}")
+	}
 
 	g.P()
 }
@@ -1266,6 +1282,7 @@ func (g *Generator) generateEnum(enum *EnumDescriptor) {
 //	packed whether the encoding is "packed" (optional; repeated primitives only)
 //	name= the original declared name
 //	enum= the name of the enum type if it is an enum-typed field.
+//	proto3 if this field is in a proto3 message
 //	def= string representation of the default value, if any.
 // The default value must be in a representation that can be used at run-time
 // to generate the default value. Thus bools become 0 and 1, for instance.
@@ -1348,6 +1365,13 @@ func (g *Generator) goTag(message *Descriptor, field *descriptor.FieldDescriptor
 	} else {
 		name = ",name=" + name
 	}
+	if message.proto3() {
+		// We only need the extra tag for []byte fields;
+		// no need to add noise for the others.
+		if *field.Type == descriptor.FieldDescriptorProto_TYPE_BYTES {
+			name += ",proto3"
+		}
+	}
 	return strconv.Quote(fmt.Sprintf("%s,%d,%s%s%s%s%s",
 		wiretype,
 		field.GetNumber(),
@@ -1433,6 +1457,8 @@ func (g *Generator) GoType(message *Descriptor, field *descriptor.FieldDescripto
 	}
 	if isRepeated(field) {
 		typ = "[]" + typ
+	} else if message != nil && message.proto3() {
+		return
 	} else if needsStar(*field.Type) {
 		typ = "*" + typ
 	}
@@ -1498,7 +1524,9 @@ func (g *Generator) generateMessage(message *Descriptor) {
 	if len(message.ExtensionRange) > 0 {
 		g.P("XXX_extensions\t\tmap[int32]", g.Pkg["proto"], ".Extension `json:\"-\"`")
 	}
-	g.P("XXX_unrecognized\t[]byte `json:\"-\"`")
+	if !message.proto3() {
+		g.P("XXX_unrecognized\t[]byte `json:\"-\"`")
+	}
 	g.Out()
 	g.P("}")
 
@@ -1634,6 +1662,11 @@ func (g *Generator) generateMessage(message *Descriptor) {
 			star = "*"
 		}
 
+		// In proto3, only generate getters for message fields.
+		if message.proto3() && *field.Type != descriptor.FieldDescriptorProto_TYPE_MESSAGE {
+			continue
+		}
+
 		// Only export getter symbols for basic types,
 		// and for messages and enums in the same package.
 		// Groups are not exported.
diff --git a/protoc-gen-go/testdata/proto3.proto b/protoc-gen-go/testdata/proto3.proto
new file mode 100644
index 0000000..ce192ae
--- /dev/null
+++ b/protoc-gen-go/testdata/proto3.proto
@@ -0,0 +1,52 @@
+// Go support for Protocol Buffers - Google's data interchange format
+//
+// Copyright 2014 The Go Authors.  All rights reserved.
+// https://github.com/golang/protobuf
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+syntax = "proto3";
+
+package proto3;
+
+message Request {
+  enum Flavour {
+    SWEET = 0;
+    SOUR = 1;
+    UMAMI = 2;
+    GOPHERLICIOUS = 3;
+  }
+  string name = 1;  // "optional" may be omitted
+  repeated int64 key = 2;
+  optional Flavour taste = 3;
+  Book book = 4;
+}
+
+message Book {
+  string title = 1;
+  bytes raw_data = 2;
+}