Thanks for your reply.
My application links against all the stub proto sources of the types I will
be creating. What I've found works is if I use the default(?) descriptor
pool (google::protobuf::DescriptorPool::generated_pool()) and the default
message factory (google::protobuf::MessageFactory::generated_factory()).
Given the type name and the content, I have a simple function that more or
less does this:
const gpb::Descriptor* descriptor =
gpb::DescriptorPool::generated_pool()->FindMessageTypeByName(
"my.package.Foo" );
gpb::MessageFactory* factory = gpb::MessageFactory::generated_factory();
const gpb::Message* prototype = factory->GetPrototype( descriptor );
gpb::Message* message = prototype->New();
gpb::Message* m = gpb::TextFormat::ParseFromString( "blah: \"some string\"
bleh: 3", message );
On Wednesday, January 16, 2013 4:15:53 PM UTC-8, m wrote:
>
> Hi All,
>
> I'm seeing an incompatibility between a dynamically generated
> google::protobuf::Message (DynamicMessage?) created with a
> google::protobuf::DynamicMessageFactory and a normal
> google::protobuf::Message.
>
> What I'm running up against ultimately comes down to this: I can't
> dynamic_cast a DynamicMessage to a known derived type of
> google::protobuf::Message. For example, let's say my proto file has the
> following message:
>
> package my.package;
>
> messsage Foo
> {
> string blah = 1;
> uint32 bleh = 2;
> }
>
>
> and I successfully create a my::package::Foo with some code along the
> lines of:
>
> const google::protobuf::Descriptor* descriptor =
> myImporter.pool()->FindMessageTypeByName(
> "my.package.Foo" );
>
> google::protobuf::Message* message = myDynamicMessageFactory.GetPrototype(
> descriptor )->New();
>
>
> after populating message successfully with other commands not shown here,
> I try to do something like:
>
> my::package::Foo foo;
> foo.CopyFrom( *message );
>
>
> and I get a segfault in CopyFrom() because ultimately the following
> doesn't work (the pointer pFoo ends up being NULL down inside
> CopyFrom()/MergeFrom()):
>
> my::package::Foo* pFoo = dynamic_cast< my::package::Foo* >( message );
>
>
> It appears as though the derived type of message is not actually
> my::package::Foo, but instead google::protobuf::DynamicMessage (or
> something like that), so naturally the dynamic_cast fails. I was sure to
> observe the output of message->DebugString() and message->GetTypeName()
> which returned all the appropriate information.
>
> Is there any way to get a real my::package::Foo object from a dynamic one?
>
>
>
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