Re: [protobuf] Re: Dynamic Message and google::protobuf::Message incompatibility
On Sat, Jan 19, 2013 at 2:13 AM, m wrote:
> The furthest I followed it was looking down into the implementation of
> CopyFrom() which calls MergeFrom(). Inside of MergeFrom() there's a spot
> where it calls something like "dynamic_cast_if_available" which returns
> NULL (failing to dynamic_cast).
Returning NULL shouldn't cause a segment fault. The generated code should
be able to handle this NULL case properly.
>
>
> On Thursday, January 17, 2013 10:20:13 PM UTC-8, Feng Xiao wrote:
>>
>> Glad that you found what works for you. What baffles me is why CopyFrom()
>> segfaults when given a DynamicMessage. DynamicMessage can't be cast to
>> Foo, but foo.CopyFrom() gets to be working with it. Did you find why it
>> segfaults?
>>
>> On Friday, January 18, 2013 3:31:48 AM UTC+8, m wrote:
>>>
>>> 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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[protobuf] Re: Dynamic Message and google::protobuf::Message incompatibility
The furthest I followed it was looking down into the implementation of
CopyFrom() which calls MergeFrom(). Inside of MergeFrom() there's a spot
where it calls something like "dynamic_cast_if_available" which returns
NULL (failing to dynamic_cast).
On Thursday, January 17, 2013 10:20:13 PM UTC-8, Feng Xiao wrote:
>
> Glad that you found what works for you. What baffles me is why CopyFrom()
> segfaults when given a DynamicMessage. DynamicMessage can't be cast to
> Foo, but foo.CopyFrom() gets to be working with it. Did you find why it
> segfaults?
>
> On Friday, January 18, 2013 3:31:48 AM UTC+8, m wrote:
>>
>> 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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[protobuf] Re: Dynamic Message and google::protobuf::Message incompatibility
Glad that you found what works for you. What baffles me is why CopyFrom()
segfaults when given a DynamicMessage. DynamicMessage can't be cast to
Foo, but foo.CopyFrom() gets to be working with it. Did you find why it
segfaults?
On Friday, January 18, 2013 3:31:48 AM UTC+8, m wrote:
>
> 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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[protobuf] Re: Dynamic Message and google::protobuf::Message incompatibility
Sorry, there's a typo on that last line. It should be:
gpb::TextFormat::ParseFromString( "blah: \"some string\" bleh: 3", message
);
On Thursday, January 17, 2013 11:31:48 AM UTC-8, m wrote:
>
> 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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[protobuf] Re: Dynamic Message and google::protobuf::Message incompatibility
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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[protobuf] Re: Dynamic Message and google::protobuf::Message incompatibility
On Thursday, January 17, 2013 8:15:53 AM 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()):
>
CopyFrom() should be able to copy a DynamicMessage to a generated message
if they share the same descriptor.
Can you post the whole generated method where the segfault happens?
>
> 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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