Add Any helper funcs to the ptypes package.
diff --git a/ptypes/any.go b/ptypes/any.go new file mode 100644 index 0000000..89e07ae --- /dev/null +++ b/ptypes/any.go
@@ -0,0 +1,136 @@ +// Go support for Protocol Buffers - Google's data interchange format +// +// Copyright 2016 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 ptypes + +// This file implements functions to marshal proto.Message to/from +// google.protobuf.Any message. + +import ( + "fmt" + "reflect" + "strings" + + "github.com/golang/protobuf/proto" + "github.com/golang/protobuf/ptypes/any" +) + +const googleApis = "type.googleapis.com/" + +// AnyMessageName returns the name of the message contained in a google.protobuf.Any message. +// +// Note that regular type assertions should be done using the Is +// function. AnyMessageName is provided for less common use cases like filtering a +// sequence of Any messages based on a set of allowed message type names. +func AnyMessageName(any *any.Any) (string, error) { + slash := strings.LastIndex(any.TypeUrl, "/") + if slash < 0 { + return "", fmt.Errorf("message type url %q is invalid", any.TypeUrl) + } + return any.TypeUrl[slash+1:], nil +} + +// MarshalAny takes the protocol buffer and encodes it into google.protobuf.Any. +func MarshalAny(pb proto.Message) (*any.Any, error) { + value, err := proto.Marshal(pb) + if err != nil { + return nil, err + } + return &any.Any{TypeUrl: googleApis + proto.MessageName(pb), Value: value}, nil +} + +// DynamicAny is a value that can be passed to UnmarshalAny to automatically +// allocate a proto.Message for the type specified in a google.protobuf.Any +// message. The allocated message is stored in the embedded proto.Message. +// +// Example: +// +// var x ptypes.DynamicAny +// if err := ptypes.UnmarshalAny(a, &x); err != nil { ... } +// fmt.Printf("unmarshaled message: %v", x.Message) +type DynamicAny struct { + proto.Message +} + +// Empty returns a new proto.Message of the type specified in a +// google.protobuf.Any message. It returns an error if corresponding message +// type isn't linked in. +func Empty(any *any.Any) (proto.Message, error) { + aname, err := AnyMessageName(any) + if err != nil { + return nil, err + } + + t := proto.MessageType(aname) + if t == nil { + return nil, fmt.Errorf("any: message type %q isn't linked in", aname) + } + return reflect.New(t.Elem()).Interface().(proto.Message), nil +} + +// UnmarshalAny parses the protocol buffer representation in a google.protobuf.Any +// message and places the decoded result in pb. It returns an error if type of +// contents of Any message does not match type of pb message. +// +// pb can be a proto.Message, or a *DynamicAny. +func UnmarshalAny(any *any.Any, pb proto.Message) error { + if d, ok := pb.(*DynamicAny); ok { + if d.Message == nil { + var err error + d.Message, err = Empty(any) + if err != nil { + return err + } + } + return UnmarshalAny(any, d.Message) + } + + aname, err := AnyMessageName(any) + if err != nil { + return err + } + + mname := proto.MessageName(pb) + if aname != mname { + return fmt.Errorf("mismatched message type: got %q want %q", aname, mname) + } + return proto.Unmarshal(any.Value, pb) +} + +// Is returns true if any value contains a given message type. +func Is(any *any.Any, pb proto.Message) bool { + aname, err := AnyMessageName(any) + if err != nil { + return false + } + + return aname == proto.MessageName(pb) +}
diff --git a/ptypes/any_test.go b/ptypes/any_test.go new file mode 100644 index 0000000..ed675b4 --- /dev/null +++ b/ptypes/any_test.go
@@ -0,0 +1,113 @@ +// Go support for Protocol Buffers - Google's data interchange format +// +// Copyright 2016 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 ptypes + +import ( + "testing" + + "github.com/golang/protobuf/proto" + pb "github.com/golang/protobuf/protoc-gen-go/descriptor" + "github.com/golang/protobuf/ptypes/any" +) + +func TestMarshalUnmarshal(t *testing.T) { + orig := &any.Any{Value: []byte("test")} + + packed, err := MarshalAny(orig) + if err != nil { + t.Errorf("MarshalAny(%+v): got: _, %v exp: _, nil", orig, err) + } + + unpacked := &any.Any{} + err = UnmarshalAny(packed, unpacked) + if err != nil || !proto.Equal(unpacked, orig) { + t.Errorf("got: %v, %+v; want nil, %+v", err, unpacked, orig) + } +} + +func TestIs(t *testing.T) { + a, err := MarshalAny(&pb.FileDescriptorProto{}) + if err != nil { + t.Fatal(err) + } + if Is(a, &pb.DescriptorProto{}) { + t.Error("FileDescriptorProto is not a DescriptorProto, but Is says it is") + } + if !Is(a, &pb.FileDescriptorProto{}) { + t.Error("FileDescriptorProto is indeed a FileDescriptorProto, but Is says it is not") + } +} + +func TestIsDifferentUrlPrefixes(t *testing.T) { + m := &pb.FileDescriptorProto{} + a := &any.Any{TypeUrl: "foo/bar/" + proto.MessageName(m)} + if !Is(a, m) { + t.Errorf("message with type url %q didn't satisfy Is for type %q", a.TypeUrl, proto.MessageName(m)) + } +} + +func TestUnmarshalDynamic(t *testing.T) { + want := &pb.FileDescriptorProto{Name: proto.String("foo")} + a, err := MarshalAny(want) + if err != nil { + t.Fatal(err) + } + var got DynamicAny + if err := UnmarshalAny(a, &got); err != nil { + t.Fatal(err) + } + if !proto.Equal(got.Message, want) { + t.Errorf("invalid result from UnmarshalAny, got %q want %q", got.Message, want) + } +} + +func TestEmpty(t *testing.T) { + want := &pb.FileDescriptorProto{} + a, err := MarshalAny(want) + if err != nil { + t.Fatal(err) + } + got, err := Empty(a) + if err != nil { + t.Fatal(err) + } + if !proto.Equal(got, want) { + t.Errorf("unequal empty message, got %q, want %q", got, want) + } + + // that's a valid type_url for a message which shouldn't be linked into this + // test binary. We want an error. + a.TypeUrl = "type.googleapis.com/google.protobuf.FieldMask" + if _, err := Empty(a); err == nil { + t.Errorf("got no error for an attempt to create a message of type %q, which shouldn't be linked in", a.TypeUrl) + } +}