Re: https://groups.google.com/forum/#!topic/grpc-io/hUYIjv97Hhc "C++ async
API"
I'm trying to use async messaging and streams. I've used the ideas from the
above post, namely, creating a CallData class per RPC method (I called mine
"Context" instead of CallData, and it inherits from a base class, but the
idea is the same).
This works fine for RPCs that don't have any streaming. But when I created
a new RPC that was identical to the others (different name, of course) but
had stream on the return value, my naive cut-n-paste solution from the
other class didn't work :-(
Here's a stripped down part of the code:
class Context_SubscribeStream : public Context {
public:
Context_SubscribeStream(grpc_control::AsyncService* service,
ServerCompletionQueue* cq) : Context (cq,service,SUBSCRIBESTREAM),
responder_(&ctx_) {
Proceed();
}
void Proceed() {
if (status_ == CREATE) {
status_ = PROCESS;
// doesn't compile:
service_->RequestSubscribeStream (&request_, &responder_, cq_,
cq_, this);
} else if (status_ == PROCESS) {
... code elided for clarity ...
status_ = FINISH;
// doesn't compile:
responder_.Finish(reply_, Status::OK, this);
} else {
GPR_ASSERT(status_ == FINISH);
delete this;
}
}
private:
SubscribeArgs request_;
SubscribeReply reply_;
ServerAsyncWriter<SubscribeReply> responder_;
};
The compiler message I get is:
g++ -std=c++0x -I../proto -I../../../contrib/google/build-ads/include
-pthread -c -o aserver.o aserver.cc
aserver.cc: In member function 'void Context_SubscribeStream::Proceed()':
aserver.cc:152: error: no matching function for call to
'grpc_open_config::grpc_control::WithAsyncMethod_Subscribe<grpc_open_config::grpc_control::WithAsyncMethod_SubscribeStream<grpc_open_config::grpc_control::WithAsyncMethod_Unsubscribe<grpc_open_config::grpc_control::Service>
> >::RequestSubscribeStream(grpc_open_config::SubscribeArgs*,
grpc::ServerAsyncWriter<grpc_open_config::SubscribeReply>*,
grpc::ServerCompletionQueue*&, grpc::ServerCompletionQueue*&,
Context_SubscribeStream* const)'
../proto/grpcidl.grpc.pb.h:141: note: candidates are: void
grpc_open_config::grpc_control::WithAsyncMethod_SubscribeStream<BaseClass>::RequestSubscribeStream(grpc::ServerContext*,
grpc_open_config::SubscribeArgs*,
grpc::ServerAsyncWriter<grpc_open_config::SubscribeReply>*,
grpc::CompletionQueue*, grpc::ServerCompletionQueue*, void*) [with
BaseClass =
grpc_open_config::grpc_control::WithAsyncMethod_Unsubscribe<grpc_open_config::grpc_control::Service>]
aserver.cc:162: error: no matching function for call to
'grpc::ServerAsyncWriter<grpc_open_config::SubscribeReply>::Finish(grpc_open_config::SubscribeReply&,
const grpc::Status&, Context_SubscribeStream* const)'
../../../contrib/google/build-ads/include/grpc++/impl/codegen/async_stream.h:434:
note: candidates are: void grpc::ServerAsyncWriter<W>::Finish(const
grpc::Status&, void*) [with W = grpc_open_config::SubscribeReply]
make-3.81: *** [aserver.o] Error 1
If I change responder_'s declaration to:
ServerAsyncResponseWriter<SubscribeReply> responder_;
Then the compiler error I get is:
g++ -std=c++0x -I../proto -I../../../contrib/google/build-ads/include
-pthread -c -o aserver.o aserver.cc
aserver.cc: In member function 'void Context_SubscribeStream::Proceed()':
aserver.cc:152: error: no matching function for call to
'grpc_open_config::grpc_control::WithAsyncMethod_Subscribe<grpc_open_config::grpc_control::WithAsyncMethod_SubscribeStream<grpc_open_config::grpc_control::WithAsyncMethod_Unsubscribe<grpc_open_config::grpc_control::Service>
> >::RequestSubscribeStream(grpc_open_config::SubscribeArgs*,
grpc::ServerAsyncResponseWriter<grpc_open_config::SubscribeReply>*,
grpc::ServerCompletionQueue*&, grpc::ServerCompletionQueue*&,
Context_SubscribeStream* const)'
../proto/grpcidl.grpc.pb.h:141: note: candidates are: void
grpc_open_config::grpc_control::WithAsyncMethod_SubscribeStream<BaseClass>::RequestSubscribeStream(grpc::ServerContext*,
grpc_open_config::SubscribeArgs*,
grpc::ServerAsyncWriter<grpc_open_config::SubscribeReply>*,
grpc::CompletionQueue*, grpc::ServerCompletionQueue*, void*) [with
BaseClass =
grpc_open_config::grpc_control::WithAsyncMethod_Unsubscribe<grpc_open_config::grpc_control::Service>]
make-3.81: *** [aserver.o] Error 1
Sadly, I'm not experienced enough in C++ to be able to make sense of the
error messages.
Anything obviously dumb I'm doing?
Thanks in advance!
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