The C based gRPC (C++, Python, Ruby, Objective-C, PHP, C#) https://grpc.io/
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/*
*
* Copyright 2014, Google Inc.
* All rights reserved.
*
* 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.
*
*/
#ifndef __GRPCPP_STREAM_H__
#define __GRPCPP_STREAM_H__
#include <grpc++/channel_interface.h>
#include <grpc++/client_context.h>
#include <grpc++/completion_queue.h>
#include <grpc++/impl/call.h>
#include <grpc++/status.h>
#include <grpc/support/log.h>
namespace grpc {
// Common interface for all client side streaming.
class ClientStreamingInterface {
public:
virtual ~ClientStreamingInterface() {}
// Wait until the stream finishes, and return the final status. When the
// client side declares it has no more message to send, either implicitly or
// by calling WritesDone, it needs to make sure there is no more message to
// be received from the server, either implicitly or by getting a false from
// a Read(). Otherwise, this implicitly cancels the stream.
virtual Status Finish() = 0;
};
// An interface that yields a sequence of R messages.
template <class R>
class ReaderInterface {
public:
virtual ~ReaderInterface() {}
// Blocking read a message and parse to msg. Returns true on success.
// The method returns false when there will be no more incoming messages,
// either because the other side has called WritesDone or the stream has
// failed (or been cancelled).
virtual bool Read(R* msg) = 0;
};
// An interface that can be fed a sequence of W messages.
template <class W>
class WriterInterface {
public:
virtual ~WriterInterface() {}
// Blocking write msg to the stream. Returns true on success.
// Returns false when the stream has been closed.
virtual bool Write(const W& msg) = 0;
};
template <class R>
class ClientReader final : public ClientStreamingInterface,
public ReaderInterface<R> {
public:
// Blocking create a stream and write the first request out.
ClientReader(ChannelInterface *channel, const RpcMethod &method,
ClientContext *context,
const google::protobuf::Message &request)
: context_(context), call_(channel->CreateCall(method, context, &cq_)) {
CallOpBuffer buf;
buf.AddSendMessage(request);
buf.AddClientSendClose();
call_.PerformOps(&buf);
cq_.Pluck(&buf);
}
virtual bool Read(R *msg) override {
CallOpBuffer buf;
buf.AddRecvMessage(msg);
call_.PerformOps(&buf);
return cq_.Pluck(&buf);
}
virtual Status Finish() override {
CallOpBuffer buf;
Status status;
buf.AddClientRecvStatus(&context_->trailing_metadata_, &status);
call_.PerformOps(&buf);
GPR_ASSERT(cq_.Pluck(&buf));
return status;
}
private:
ClientContext* context_;
CompletionQueue cq_;
Call call_;
};
template <class W>
class ClientWriter final : public ClientStreamingInterface,
public WriterInterface<W> {
public:
// Blocking create a stream.
ClientWriter(ChannelInterface *channel, const RpcMethod &method,
ClientContext *context,
google::protobuf::Message *response)
: context_(context), response_(response),
call_(channel->CreateCall(method, context, &cq_)) {}
virtual bool Write(const W& msg) override {
CallOpBuffer buf;
buf.AddSendMessage(msg);
call_.PerformOps(&buf);
return cq_.Pluck(&buf);
}
virtual bool WritesDone() {
CallOpBuffer buf;
buf.AddClientSendClose();
call_.PerformOps(&buf);
return cq_.Pluck(&buf);
}
// Read the final response and wait for the final status.
virtual Status Finish() override {
CallOpBuffer buf;
Status status;
buf.AddRecvMessage(response_);
buf.AddClientRecvStatus(&context_->trailing_metadata_, &status);
call_.PerformOps(&buf);
GPR_ASSERT(cq_.Pluck(&buf));
return status;
}
private:
ClientContext* context_;
google::protobuf::Message *const response_;
CompletionQueue cq_;
Call call_;
};
// Client-side interface for bi-directional streaming.
template <class W, class R>
class ClientReaderWriter final : public ClientStreamingInterface,
public WriterInterface<W>,
public ReaderInterface<R> {
public:
// Blocking create a stream.
ClientReaderWriter(ChannelInterface *channel,
const RpcMethod &method, ClientContext *context)
: context_(context), call_(channel->CreateCall(method, context, &cq_)) {}
virtual bool Read(R *msg) override {
CallOpBuffer buf;
buf.AddRecvMessage(msg);
call_.PerformOps(&buf);
return cq_.Pluck(&buf);
}
virtual bool Write(const W& msg) override {
CallOpBuffer buf;
buf.AddSendMessage(msg);
call_.PerformOps(&buf);
return cq_.Pluck(&buf);
}
virtual bool WritesDone() {
CallOpBuffer buf;
buf.AddClientSendClose();
call_.PerformOps(&buf);
return cq_.Pluck(&buf);
}
virtual Status Finish() override {
CallOpBuffer buf;
Status status;
buf.AddClientRecvStatus(&context_->trailing_metadata_, &status);
call_.PerformOps(&buf);
GPR_ASSERT(cq_.Pluck(&buf));
return status;
}
private:
ClientContext* context_;
CompletionQueue cq_;
Call call_;
};
template <class R>
class ServerReader final : public ReaderInterface<R> {
public:
explicit ServerReader(Call* call) : call_(call) {}
virtual bool Read(R* msg) override {
CallOpBuffer buf;
buf.AddRecvMessage(msg);
call_->PerformOps(&buf);
return call_->cq()->Pluck(&buf);
}
private:
Call* call_;
};
template <class W>
class ServerWriter final : public WriterInterface<W> {
public:
explicit ServerWriter(Call* call) : call_(call) {}
virtual bool Write(const W& msg) override {
CallOpBuffer buf;
buf.AddSendMessage(msg);
call_->PerformOps(&buf);
return call_->cq()->Pluck(&buf);
}
private:
Call* call_;
};
// Server-side interface for bi-directional streaming.
template <class W, class R>
class ServerReaderWriter final : public WriterInterface<W>,
public ReaderInterface<R> {
public:
explicit ServerReaderWriter(Call* call) : call_(call) {}
virtual bool Read(R* msg) override {
CallOpBuffer buf;
buf.AddRecvMessage(msg);
call_->PerformOps(&buf);
return call_->cq()->Pluck(&buf);
}
virtual bool Write(const W& msg) override {
CallOpBuffer buf;
buf.AddSendMessage(msg);
call_->PerformOps(&buf);
return call_->cq()->Pluck(&buf);
}
private:
CompletionQueue* cq_;
Call* call_;
};
// Async interfaces
// Common interface for all client side streaming.
class ClientAsyncStreamingInterface {
public:
virtual ~ClientAsyncStreamingInterface() {}
virtual void Finish(Status* status, void* tag) = 0;
};
// An interface that yields a sequence of R messages.
template <class R>
class AsyncReaderInterface {
public:
virtual ~AsyncReaderInterface() {}
virtual void Read(R* msg, void* tag) = 0;
};
// An interface that can be fed a sequence of W messages.
template <class W>
class AsyncWriterInterface {
public:
virtual ~AsyncWriterInterface() {}
virtual void Write(const W& msg, void* tag) = 0;
};
template <class R>
class ClientAsyncReader final : public ClientAsyncStreamingInterface,
public AsyncReaderInterface<R> {
public:
// Blocking create a stream and write the first request out.
ClientAsyncReader(ChannelInterface *channel, const RpcMethod &method,
ClientContext *context,
const google::protobuf::Message &request, void* tag)
: call_(channel->CreateCall(method, context, &cq_)) {
init_buf_.Reset(tag);
init_buf_.AddSendMessage(request);
init_buf_.AddClientSendClose();
call_.PerformOps(&init_buf_);
}
virtual void Read(R *msg, void* tag) override {
read_buf_.Reset(tag);
read_buf_.AddRecvMessage(msg);
call_.PerformOps(&read_buf_);
}
virtual void Finish(Status* status, void* tag) override {
finish_buf_.Reset(tag);
finish_buf_.AddClientRecvStatus(nullptr, status); // TODO metadata
call_.PerformOps(&finish_buf_);
}
private:
CompletionQueue cq_;
Call call_;
CallOpBuffer init_buf_;
CallOpBuffer read_buf_;
CallOpBuffer finish_buf_;
};
template <class W>
class ClientAsyncWriter final : public ClientAsyncStreamingInterface,
public WriterInterface<W> {
public:
// Blocking create a stream.
ClientAsyncWriter(ChannelInterface *channel, const RpcMethod &method,
ClientContext *context,
google::protobuf::Message *response)
: response_(response),
call_(channel->CreateCall(method, context, &cq_)) {}
virtual void Write(const W& msg, void* tag) override {
write_buf_.Reset(tag);
write_buf_.AddSendMessage(msg);
call_.PerformOps(&write_buf_);
}
virtual void WritesDone(void* tag) override {
writes_done_buf_.Reset(tag);
writes_done_buf_.AddClientSendClose();
call_.PerformOps(&writes_done_buf_);
}
virtual void Finish(Status* status, void* tag) override {
finish_buf_.Reset(tag);
finish_buf_.AddRecvMessage(response_);
finish_buf_.AddClientRecvStatus(nullptr, status); // TODO metadata
call_.PerformOps(&finish_buf_);
}
private:
google::protobuf::Message *const response_;
CompletionQueue cq_;
Call call_;
CallOpBuffer write_buf_;
CallOpBuffer writes_done_buf_;
CallOpBuffer finish_buf_;
};
// Client-side interface for bi-directional streaming.
template <class W, class R>
class ClientAsyncReaderWriter final : public ClientAsyncStreamingInterface,
public AsyncWriterInterface<W>,
public AsyncReaderInterface<R> {
public:
ClientAsyncReaderWriter(ChannelInterface *channel,
const RpcMethod &method, ClientContext *context)
: call_(channel->CreateCall(method, context, &cq_)) {}
virtual void Read(R *msg, void* tag) override {
read_buf_.Reset(tag);
read_buf_.AddRecvMessage(msg);
call_.PerformOps(&read_buf_);
}
virtual void Write(const W& msg, void* tag) override {
write_buf_.Reset(tag);
write_buf_.AddSendMessage(msg);
call_.PerformOps(&write_buf_);
}
virtual void WritesDone(void* tag) override {
writes_done_buf_.Reset(tag);
writes_done_buf_.AddClientSendClose();
call_.PerformOps(&writes_done_buf_);
}
virtual void Finish(Status* status, void* tag) override {
finish_buf_.Reset(tag);
finish_buf_.AddClientRecvStatus(nullptr, status); // TODO metadata
call_.PerformOps(&finish_buf_);
}
private:
CompletionQueue cq_;
Call call_;
CallOpBuffer read_buf_;
CallOpBuffer write_buf_;
CallOpBuffer writes_done_buf_;
CallOpBuffer finish_buf_;
};
// TODO(yangg) Move out of stream.h
template <class W>
class ServerAsyncResponseWriter final {
public:
explicit ServerAsyncResponseWriter(Call* call) : call_(call) {}
virtual void Write(const W& msg, void* tag) override {
CallOpBuffer buf;
buf.AddSendMessage(msg);
call_->PerformOps(&buf);
}
private:
Call* call_;
};
template <class R>
class ServerAsyncReader : public AsyncReaderInterface<R> {
public:
explicit ServerAsyncReader(Call* call) : call_(call) {}
virtual void Read(R* msg, void* tag) {
// TODO
}
private:
Call* call_;
};
template <class W>
class ServerAsyncWriter : public AsyncWriterInterface<W> {
public:
explicit ServerAsyncWriter(Call* call) : call_(call) {}
virtual void Write(const W& msg, void* tag) {
// TODO
}
private:
Call* call_;
};
// Server-side interface for bi-directional streaming.
template <class W, class R>
class ServerAsyncReaderWriter : public AsyncWriterInterface<W>,
public AsyncReaderInterface<R> {
public:
explicit ServerAsyncReaderWriter(Call* call) : call_(call) {}
virtual void Read(R* msg, void* tag) {
// TODO
}
virtual void Write(const W& msg, void* tag) {
// TODO
}
private:
Call* call_;
};
} // namespace grpc
#endif // __GRPCPP_STREAM_H__