async_stream.h

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 *
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#ifndef GRPCXX_IMPL_CODEGEN_ASYNC_STREAM_H
#define GRPCXX_IMPL_CODEGEN_ASYNC_STREAM_H

#include <grpc++/impl/codegen/call.h>
#include <grpc++/impl/codegen/channel_interface.h>
#include <grpc++/impl/codegen/core_codegen_interface.h>
#include <grpc++/impl/codegen/server_context.h>
#include <grpc++/impl/codegen/service_type.h>
#include <grpc++/impl/codegen/status.h>

namespace grpc {

class CompletionQueue;

class ClientAsyncStreamingInterface {
 public:
  virtual ~ClientAsyncStreamingInterface() {}

  virtual void ReadInitialMetadata(void* tag) = 0;

  virtual void Finish(Status* status, void* tag) = 0;
};

template <class R>
class AsyncReaderInterface {
 public:
  virtual ~AsyncReaderInterface() {}

  virtual void Read(R* msg, void* tag) = 0;
};

template <class W>
class AsyncWriterInterface {
 public:
  virtual ~AsyncWriterInterface() {}

  virtual void Write(const W& msg, void* tag) = 0;

  virtual void Write(const W& msg, WriteOptions options, void* tag) = 0;

  void WriteLast(const W& msg, WriteOptions options, void* tag) {
    Write(msg, options.set_last_message(), tag);
  }
};

template <class R>
class ClientAsyncReaderInterface : public ClientAsyncStreamingInterface,
                                   public AsyncReaderInterface<R> {};

template <class R>
class ClientAsyncReader final : public ClientAsyncReaderInterface<R> {
 public:
  template <class W>
  ClientAsyncReader(ChannelInterface* channel, CompletionQueue* cq,
                    const RpcMethod& method, ClientContext* context,
                    const W& request, void* tag)
      : context_(context), call_(channel->CreateCall(method, context, cq)) {
    init_ops_.set_output_tag(tag);
    init_ops_.SendInitialMetadata(context->send_initial_metadata_,
                                  context->initial_metadata_flags());
    // TODO(ctiller): don't assert
    GPR_CODEGEN_ASSERT(init_ops_.SendMessage(request).ok());
    init_ops_.ClientSendClose();
    call_.PerformOps(&init_ops_);
  }

  void ReadInitialMetadata(void* tag) override {
    GPR_CODEGEN_ASSERT(!context_->initial_metadata_received_);

    meta_ops_.set_output_tag(tag);
    meta_ops_.RecvInitialMetadata(context_);
    call_.PerformOps(&meta_ops_);
  }

  void Read(R* msg, void* tag) override {
    read_ops_.set_output_tag(tag);
    if (!context_->initial_metadata_received_) {
      read_ops_.RecvInitialMetadata(context_);
    }
    read_ops_.RecvMessage(msg);
    call_.PerformOps(&read_ops_);
  }

  void Finish(Status* status, void* tag) override {
    finish_ops_.set_output_tag(tag);
    if (!context_->initial_metadata_received_) {
      finish_ops_.RecvInitialMetadata(context_);
    }
    finish_ops_.ClientRecvStatus(context_, status);
    call_.PerformOps(&finish_ops_);
  }

 private:
  ClientContext* context_;
  Call call_;
  CallOpSet<CallOpSendInitialMetadata, CallOpSendMessage, CallOpClientSendClose>
      init_ops_;
  CallOpSet<CallOpRecvInitialMetadata> meta_ops_;
  CallOpSet<CallOpRecvInitialMetadata, CallOpRecvMessage<R>> read_ops_;
  CallOpSet<CallOpRecvInitialMetadata, CallOpClientRecvStatus> finish_ops_;
};

template <class W>
class ClientAsyncWriterInterface : public ClientAsyncStreamingInterface,
                                   public AsyncWriterInterface<W> {
 public:
  virtual void WritesDone(void* tag) = 0;
};

template <class W>
class ClientAsyncWriter final : public ClientAsyncWriterInterface<W> {
 public:
  template <class R>
  ClientAsyncWriter(ChannelInterface* channel, CompletionQueue* cq,
                    const RpcMethod& method, ClientContext* context,
                    R* response, void* tag)
      : context_(context), call_(channel->CreateCall(method, context, cq)) {
    finish_ops_.RecvMessage(response);
    finish_ops_.AllowNoMessage();
    // if corked bit is set in context, we buffer up the initial metadata to
    // coalesce with later message to be sent. No op is performed.
    if (context_->initial_metadata_corked_) {
      write_ops_.SendInitialMetadata(context->send_initial_metadata_,
                                     context->initial_metadata_flags());
    } else {
      write_ops_.set_output_tag(tag);
      write_ops_.SendInitialMetadata(context->send_initial_metadata_,
                                     context->initial_metadata_flags());
      call_.PerformOps(&write_ops_);
    }
  }

  void ReadInitialMetadata(void* tag) override {
    GPR_CODEGEN_ASSERT(!context_->initial_metadata_received_);

    meta_ops_.set_output_tag(tag);
    meta_ops_.RecvInitialMetadata(context_);
    call_.PerformOps(&meta_ops_);
  }

  void Write(const W& msg, void* tag) override {
    write_ops_.set_output_tag(tag);
    // TODO(ctiller): don't assert
    GPR_CODEGEN_ASSERT(write_ops_.SendMessage(msg).ok());
    call_.PerformOps(&write_ops_);
  }

  void Write(const W& msg, WriteOptions options, void* tag) override {
    write_ops_.set_output_tag(tag);
    if (options.is_last_message()) {
      options.set_buffer_hint();
      write_ops_.ClientSendClose();
    }
    // TODO(ctiller): don't assert
    GPR_CODEGEN_ASSERT(write_ops_.SendMessage(msg, options).ok());
    call_.PerformOps(&write_ops_);
  }

  void WritesDone(void* tag) override {
    write_ops_.set_output_tag(tag);
    write_ops_.ClientSendClose();
    call_.PerformOps(&write_ops_);
  }

  void Finish(Status* status, void* tag) override {
    finish_ops_.set_output_tag(tag);
    if (!context_->initial_metadata_received_) {
      finish_ops_.RecvInitialMetadata(context_);
    }
    finish_ops_.ClientRecvStatus(context_, status);
    call_.PerformOps(&finish_ops_);
  }

 private:
  ClientContext* context_;
  Call call_;
  CallOpSet<CallOpRecvInitialMetadata> meta_ops_;
  CallOpSet<CallOpSendInitialMetadata, CallOpSendMessage, CallOpClientSendClose>
      write_ops_;
  CallOpSet<CallOpRecvInitialMetadata, CallOpGenericRecvMessage,
            CallOpClientRecvStatus>
      finish_ops_;
};

template <class W, class R>
class ClientAsyncReaderWriterInterface : public ClientAsyncStreamingInterface,
                                         public AsyncWriterInterface<W>,
                                         public AsyncReaderInterface<R> {
 public:
  virtual void WritesDone(void* tag) = 0;
};

template <class W, class R>
class ClientAsyncReaderWriter final
    : public ClientAsyncReaderWriterInterface<W, R> {
 public:
  ClientAsyncReaderWriter(ChannelInterface* channel, CompletionQueue* cq,
                          const RpcMethod& method, ClientContext* context,
                          void* tag)
      : context_(context), call_(channel->CreateCall(method, context, cq)) {
    if (context_->initial_metadata_corked_) {
      // if corked bit is set in context, we buffer up the initial metadata to
      // coalesce with later message to be sent. No op is performed.
      write_ops_.SendInitialMetadata(context->send_initial_metadata_,
                                     context->initial_metadata_flags());
    } else {
      write_ops_.set_output_tag(tag);
      write_ops_.SendInitialMetadata(context->send_initial_metadata_,
                                     context->initial_metadata_flags());
      call_.PerformOps(&write_ops_);
    }
  }

  void ReadInitialMetadata(void* tag) override {
    GPR_CODEGEN_ASSERT(!context_->initial_metadata_received_);

    meta_ops_.set_output_tag(tag);
    meta_ops_.RecvInitialMetadata(context_);
    call_.PerformOps(&meta_ops_);
  }

  void Read(R* msg, void* tag) override {
    read_ops_.set_output_tag(tag);
    if (!context_->initial_metadata_received_) {
      read_ops_.RecvInitialMetadata(context_);
    }
    read_ops_.RecvMessage(msg);
    call_.PerformOps(&read_ops_);
  }

  void Write(const W& msg, void* tag) override {
    write_ops_.set_output_tag(tag);
    // TODO(ctiller): don't assert
    GPR_CODEGEN_ASSERT(write_ops_.SendMessage(msg).ok());
    call_.PerformOps(&write_ops_);
  }

  void Write(const W& msg, WriteOptions options, void* tag) override {
    write_ops_.set_output_tag(tag);
    if (options.is_last_message()) {
      options.set_buffer_hint();
      write_ops_.ClientSendClose();
    }
    // TODO(ctiller): don't assert
    GPR_CODEGEN_ASSERT(write_ops_.SendMessage(msg, options).ok());
    call_.PerformOps(&write_ops_);
  }

  void WritesDone(void* tag) override {
    write_ops_.set_output_tag(tag);
    write_ops_.ClientSendClose();
    call_.PerformOps(&write_ops_);
  }

  void Finish(Status* status, void* tag) override {
    finish_ops_.set_output_tag(tag);
    if (!context_->initial_metadata_received_) {
      finish_ops_.RecvInitialMetadata(context_);
    }
    finish_ops_.ClientRecvStatus(context_, status);
    call_.PerformOps(&finish_ops_);
  }

 private:
  ClientContext* context_;
  Call call_;
  CallOpSet<CallOpRecvInitialMetadata> meta_ops_;
  CallOpSet<CallOpRecvInitialMetadata, CallOpRecvMessage<R>> read_ops_;
  CallOpSet<CallOpSendInitialMetadata, CallOpSendMessage, CallOpClientSendClose>
      write_ops_;
  CallOpSet<CallOpRecvInitialMetadata, CallOpClientRecvStatus> finish_ops_;
};

template <class W, class R>
class ServerAsyncReaderInterface : public ServerAsyncStreamingInterface,
                                   public AsyncReaderInterface<R> {
 public:
  virtual void Finish(const W& msg, const Status& status, void* tag) = 0;

  virtual void FinishWithError(const Status& status, void* tag) = 0;
};

template <class W, class R>
class ServerAsyncReader final : public ServerAsyncReaderInterface<W, R> {
 public:
  explicit ServerAsyncReader(ServerContext* ctx)
      : call_(nullptr, nullptr, nullptr), ctx_(ctx) {}

  void SendInitialMetadata(void* tag) override {
    GPR_CODEGEN_ASSERT(!ctx_->sent_initial_metadata_);

    meta_ops_.set_output_tag(tag);
    meta_ops_.SendInitialMetadata(ctx_->initial_metadata_,
                                  ctx_->initial_metadata_flags());
    if (ctx_->compression_level_set()) {
      meta_ops_.set_compression_level(ctx_->compression_level());
    }
    ctx_->sent_initial_metadata_ = true;
    call_.PerformOps(&meta_ops_);
  }

  void Read(R* msg, void* tag) override {
    read_ops_.set_output_tag(tag);
    read_ops_.RecvMessage(msg);
    call_.PerformOps(&read_ops_);
  }

  void Finish(const W& msg, const Status& status, void* tag) override {
    finish_ops_.set_output_tag(tag);
    if (!ctx_->sent_initial_metadata_) {
      finish_ops_.SendInitialMetadata(ctx_->initial_metadata_,
                                      ctx_->initial_metadata_flags());
      if (ctx_->compression_level_set()) {
        finish_ops_.set_compression_level(ctx_->compression_level());
      }
      ctx_->sent_initial_metadata_ = true;
    }
    // The response is dropped if the status is not OK.
    if (status.ok()) {
      finish_ops_.ServerSendStatus(ctx_->trailing_metadata_,
                                   finish_ops_.SendMessage(msg));
    } else {
      finish_ops_.ServerSendStatus(ctx_->trailing_metadata_, status);
    }
    call_.PerformOps(&finish_ops_);
  }

  void FinishWithError(const Status& status, void* tag) override {
    GPR_CODEGEN_ASSERT(!status.ok());
    finish_ops_.set_output_tag(tag);
    if (!ctx_->sent_initial_metadata_) {
      finish_ops_.SendInitialMetadata(ctx_->initial_metadata_,
                                      ctx_->initial_metadata_flags());
      if (ctx_->compression_level_set()) {
        finish_ops_.set_compression_level(ctx_->compression_level());
      }
      ctx_->sent_initial_metadata_ = true;
    }
    finish_ops_.ServerSendStatus(ctx_->trailing_metadata_, status);
    call_.PerformOps(&finish_ops_);
  }

 private:
  void BindCall(Call* call) override { call_ = *call; }

  Call call_;
  ServerContext* ctx_;
  CallOpSet<CallOpSendInitialMetadata> meta_ops_;
  CallOpSet<CallOpRecvMessage<R>> read_ops_;
  CallOpSet<CallOpSendInitialMetadata, CallOpSendMessage,
            CallOpServerSendStatus>
      finish_ops_;
};

template <class W>
class ServerAsyncWriterInterface : public ServerAsyncStreamingInterface,
                                   public AsyncWriterInterface<W> {
 public:
  virtual void Finish(const Status& status, void* tag) = 0;

  virtual void WriteAndFinish(const W& msg, WriteOptions options,
                              const Status& status, void* tag) = 0;
};

template <class W>
class ServerAsyncWriter final : public ServerAsyncWriterInterface<W> {
 public:
  explicit ServerAsyncWriter(ServerContext* ctx)
      : call_(nullptr, nullptr, nullptr), ctx_(ctx) {}

  void SendInitialMetadata(void* tag) override {
    GPR_CODEGEN_ASSERT(!ctx_->sent_initial_metadata_);

    meta_ops_.set_output_tag(tag);
    meta_ops_.SendInitialMetadata(ctx_->initial_metadata_,
                                  ctx_->initial_metadata_flags());
    if (ctx_->compression_level_set()) {
      meta_ops_.set_compression_level(ctx_->compression_level());
    }
    ctx_->sent_initial_metadata_ = true;
    call_.PerformOps(&meta_ops_);
  }

  void Write(const W& msg, void* tag) override {
    write_ops_.set_output_tag(tag);
    EnsureInitialMetadataSent(&write_ops_);
    // TODO(ctiller): don't assert
    GPR_CODEGEN_ASSERT(write_ops_.SendMessage(msg).ok());
    call_.PerformOps(&write_ops_);
  }

  void Write(const W& msg, WriteOptions options, void* tag) override {
    write_ops_.set_output_tag(tag);
    if (options.is_last_message()) {
      options.set_buffer_hint();
    }

    EnsureInitialMetadataSent(&write_ops_);
    // TODO(ctiller): don't assert
    GPR_CODEGEN_ASSERT(write_ops_.SendMessage(msg, options).ok());
    call_.PerformOps(&write_ops_);
  }

  void WriteAndFinish(const W& msg, WriteOptions options, const Status& status,
                      void* tag) override {
    write_ops_.set_output_tag(tag);
    EnsureInitialMetadataSent(&write_ops_);
    options.set_buffer_hint();
    GPR_CODEGEN_ASSERT(write_ops_.SendMessage(msg, options).ok());
    write_ops_.ServerSendStatus(ctx_->trailing_metadata_, status);
    call_.PerformOps(&write_ops_);
  }

  void Finish(const Status& status, void* tag) override {
    finish_ops_.set_output_tag(tag);
    EnsureInitialMetadataSent(&finish_ops_);
    finish_ops_.ServerSendStatus(ctx_->trailing_metadata_, status);
    call_.PerformOps(&finish_ops_);
  }

 private:
  void BindCall(Call* call) override { call_ = *call; }

  template <class T>
  void EnsureInitialMetadataSent(T* ops) {
    if (!ctx_->sent_initial_metadata_) {
      ops->SendInitialMetadata(ctx_->initial_metadata_,
                               ctx_->initial_metadata_flags());
      if (ctx_->compression_level_set()) {
        ops->set_compression_level(ctx_->compression_level());
      }
      ctx_->sent_initial_metadata_ = true;
    }
  }

  Call call_;
  ServerContext* ctx_;
  CallOpSet<CallOpSendInitialMetadata> meta_ops_;
  CallOpSet<CallOpSendInitialMetadata, CallOpSendMessage,
            CallOpServerSendStatus>
      write_ops_;
  CallOpSet<CallOpSendInitialMetadata, CallOpServerSendStatus> finish_ops_;
};

template <class W, class R>
class ServerAsyncReaderWriterInterface : public ServerAsyncStreamingInterface,
                                         public AsyncWriterInterface<W>,
                                         public AsyncReaderInterface<R> {
 public:
  virtual void Finish(const Status& status, void* tag) = 0;

  virtual void WriteAndFinish(const W& msg, WriteOptions options,
                              const Status& status, void* tag) = 0;
};

template <class W, class R>
class ServerAsyncReaderWriter final
    : public ServerAsyncReaderWriterInterface<W, R> {
 public:
  explicit ServerAsyncReaderWriter(ServerContext* ctx)
      : call_(nullptr, nullptr, nullptr), ctx_(ctx) {}

  void SendInitialMetadata(void* tag) override {
    GPR_CODEGEN_ASSERT(!ctx_->sent_initial_metadata_);

    meta_ops_.set_output_tag(tag);
    meta_ops_.SendInitialMetadata(ctx_->initial_metadata_,
                                  ctx_->initial_metadata_flags());
    if (ctx_->compression_level_set()) {
      meta_ops_.set_compression_level(ctx_->compression_level());
    }
    ctx_->sent_initial_metadata_ = true;
    call_.PerformOps(&meta_ops_);
  }

  void Read(R* msg, void* tag) override {
    read_ops_.set_output_tag(tag);
    read_ops_.RecvMessage(msg);
    call_.PerformOps(&read_ops_);
  }

  void Write(const W& msg, void* tag) override {
    write_ops_.set_output_tag(tag);
    EnsureInitialMetadataSent(&write_ops_);
    // TODO(ctiller): don't assert
    GPR_CODEGEN_ASSERT(write_ops_.SendMessage(msg).ok());
    call_.PerformOps(&write_ops_);
  }

  void Write(const W& msg, WriteOptions options, void* tag) override {
    write_ops_.set_output_tag(tag);
    if (options.is_last_message()) {
      options.set_buffer_hint();
    }
    EnsureInitialMetadataSent(&write_ops_);
    GPR_CODEGEN_ASSERT(write_ops_.SendMessage(msg, options).ok());
    call_.PerformOps(&write_ops_);
  }

  void WriteAndFinish(const W& msg, WriteOptions options, const Status& status,
                      void* tag) override {
    write_ops_.set_output_tag(tag);
    EnsureInitialMetadataSent(&write_ops_);
    options.set_buffer_hint();
    GPR_CODEGEN_ASSERT(write_ops_.SendMessage(msg, options).ok());
    write_ops_.ServerSendStatus(ctx_->trailing_metadata_, status);
    call_.PerformOps(&write_ops_);
  }

  void Finish(const Status& status, void* tag) override {
    finish_ops_.set_output_tag(tag);
    EnsureInitialMetadataSent(&finish_ops_);

    finish_ops_.ServerSendStatus(ctx_->trailing_metadata_, status);
    call_.PerformOps(&finish_ops_);
  }

 private:
  friend class ::grpc::Server;

  void BindCall(Call* call) override { call_ = *call; }

  template <class T>
  void EnsureInitialMetadataSent(T* ops) {
    if (!ctx_->sent_initial_metadata_) {
      ops->SendInitialMetadata(ctx_->initial_metadata_,
                               ctx_->initial_metadata_flags());
      if (ctx_->compression_level_set()) {
        ops->set_compression_level(ctx_->compression_level());
      }
      ctx_->sent_initial_metadata_ = true;
    }
  }

  Call call_;
  ServerContext* ctx_;
  CallOpSet<CallOpSendInitialMetadata> meta_ops_;
  CallOpSet<CallOpRecvMessage<R>> read_ops_;
  CallOpSet<CallOpSendInitialMetadata, CallOpSendMessage,
            CallOpServerSendStatus>
      write_ops_;
  CallOpSet<CallOpSendInitialMetadata, CallOpServerSendStatus> finish_ops_;
};

}  // namespace grpc

#endif  // GRPCXX_IMPL_CODEGEN_ASYNC_STREAM_H