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Add Any helper funcs to the ptypes package.
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‎ptypes/any.go

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// Go support for Protocol Buffers - Google's data interchange format
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//
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// Copyright 2016 The Go Authors. All rights reserved.
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// https://github.com/golang/protobuf
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following disclaimer
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// in the documentation and/or other materials provided with the
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// distribution.
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// * Neither the name of Google Inc. nor the names of its
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// contributors may be used to endorse or promote products derived from
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// this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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package ptypes
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// This file implements functions to marshal proto.Message to/from
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// google.protobuf.Any message.
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import (
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"fmt"
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"reflect"
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"strings"
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"github.com/golang/protobuf/proto"
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"github.com/golang/protobuf/ptypes/any"
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)
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const googleApis = "type.googleapis.com/"
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// AnyMessageName returns the name of the message contained in a google.protobuf.Any message.
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//
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// Note that regular type assertions should be done using the Is
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// function. AnyMessageName is provided for less common use cases like filtering a
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// sequence of Any messages based on a set of allowed message type names.
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func AnyMessageName(any *any.Any) (string, error) {
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slash := strings.LastIndex(any.TypeUrl, "/")
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if slash < 0 {
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return "", fmt.Errorf("message type url %q is invalid", any.TypeUrl)
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}
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return any.TypeUrl[slash+1:], nil
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}
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// MarshalAny takes the protocol buffer and encodes it into google.protobuf.Any.
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func MarshalAny(pb proto.Message) (*any.Any, error) {
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value, err := proto.Marshal(pb)
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if err != nil {
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return nil, err
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}
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return &any.Any{TypeUrl: googleApis + proto.MessageName(pb), Value: value}, nil
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}
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// DynamicAny is a value that can be passed to UnmarshalAny to automatically
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// allocate a proto.Message for the type specified in a google.protobuf.Any
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// message. The allocated message is stored in the embedded proto.Message.
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//
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// Example:
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//
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// var x ptypes.DynamicAny
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// if err := ptypes.UnmarshalAny(a, &x); err != nil { ... }
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// fmt.Printf("unmarshaled message: %v", x.Message)
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type DynamicAny struct {
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proto.Message
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}
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// Empty returns a new proto.Message of the type specified in a
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// google.protobuf.Any message. It returns an error if corresponding message
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// type isn't linked in.
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func Empty(any *any.Any) (proto.Message, error) {
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aname, err := AnyMessageName(any)
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if err != nil {
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return nil, err
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}
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t := proto.MessageType(aname)
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if t == nil {
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return nil, fmt.Errorf("any: message type %q isn't linked in", aname)
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}
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return reflect.New(t.Elem()).Interface().(proto.Message), nil
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}
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// UnmarshalAny parses the protocol buffer representation in a google.protobuf.Any
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// message and places the decoded result in pb. It returns an error if type of
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// contents of Any message does not match type of pb message.
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//
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// pb can be a proto.Message, or a *DynamicAny.
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func UnmarshalAny(any *any.Any, pb proto.Message) error {
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if d, ok := pb.(*DynamicAny); ok {
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if d.Message == nil {
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var err error
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d.Message, err = Empty(any)
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if err != nil {
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return err
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}
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}
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return UnmarshalAny(any, d.Message)
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}
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aname, err := AnyMessageName(any)
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if err != nil {
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return err
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}
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mname := proto.MessageName(pb)
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if aname != mname {
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return fmt.Errorf("mismatched message type: got %q want %q", aname, mname)
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}
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return proto.Unmarshal(any.Value, pb)
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}
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// Is returns true if any value contains a given message type.
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func Is(any *any.Any, pb proto.Message) bool {
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aname, err := AnyMessageName(any)
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if err != nil {
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return false
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}
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return aname == proto.MessageName(pb)
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}

‎ptypes/any_test.go

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// Go support for Protocol Buffers - Google's data interchange format
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//
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// Copyright 2016 The Go Authors. All rights reserved.
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// https://github.com/golang/protobuf
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following disclaimer
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// in the documentation and/or other materials provided with the
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// distribution.
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// * Neither the name of Google Inc. nor the names of its
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// contributors may be used to endorse or promote products derived from
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// this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
25+
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
26+
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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package ptypes
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import (
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"testing"
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"github.com/golang/protobuf/proto"
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pb "github.com/golang/protobuf/protoc-gen-go/descriptor"
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"github.com/golang/protobuf/ptypes/any"
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)
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func TestMarshalUnmarshal(t *testing.T) {
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orig := &any.Any{Value: []byte("test")}
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packed, err := MarshalAny(orig)
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if err != nil {
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t.Errorf("MarshalAny(%+v): got: _, %v exp: _, nil", orig, err)
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}
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unpacked := &any.Any{}
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err = UnmarshalAny(packed, unpacked)
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if err != nil || !proto.Equal(unpacked, orig) {
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t.Errorf("got: %v, %+v; want nil, %+v", err, unpacked, orig)
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}
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}
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func TestIs(t *testing.T) {
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a, err := MarshalAny(&pb.FileDescriptorProto{})
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if err != nil {
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t.Fatal(err)
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}
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if Is(a, &pb.DescriptorProto{}) {
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t.Error("FileDescriptorProto is not a DescriptorProto, but Is says it is")
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}
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if !Is(a, &pb.FileDescriptorProto{}) {
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t.Error("FileDescriptorProto is indeed a FileDescriptorProto, but Is says it is not")
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}
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}
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func TestIsDifferentUrlPrefixes(t *testing.T) {
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m := &pb.FileDescriptorProto{}
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a := &any.Any{TypeUrl: "foo/bar/" + proto.MessageName(m)}
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if !Is(a, m) {
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t.Errorf("message with type url %q didn't satisfy Is for type %q", a.TypeUrl, proto.MessageName(m))
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}
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}
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func TestUnmarshalDynamic(t *testing.T) {
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want := &pb.FileDescriptorProto{Name: proto.String("foo")}
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a, err := MarshalAny(want)
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if err != nil {
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t.Fatal(err)
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}
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var got DynamicAny
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if err := UnmarshalAny(a, &got); err != nil {
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t.Fatal(err)
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}
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if !proto.Equal(got.Message, want) {
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t.Errorf("invalid result from UnmarshalAny, got %q want %q", got.Message, want)
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}
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}
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func TestEmpty(t *testing.T) {
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want := &pb.FileDescriptorProto{}
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a, err := MarshalAny(want)
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if err != nil {
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t.Fatal(err)
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}
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got, err := Empty(a)
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if err != nil {
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t.Fatal(err)
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}
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if !proto.Equal(got, want) {
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t.Errorf("unequal empty message, got %q, want %q", got, want)
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}
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// that's a valid type_url for a message which shouldn't be linked into this
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// test binary. We want an error.
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a.TypeUrl = "type.googleapis.com/google.protobuf.FieldMask"
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if _, err := Empty(a); err == nil {
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t.Errorf("got no error for an attempt to create a message of type %q, which shouldn't be linked in", a.TypeUrl)
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}
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}

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