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Pods/gRPC-C++/include/grpcpp/generic/generic_stub.h

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+//
+//
+// Copyright 2015 gRPC authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+//
+
+#ifndef GRPCPP_GENERIC_GENERIC_STUB_H
+#define GRPCPP_GENERIC_GENERIC_STUB_H
+
+#include <functional>
+
+#include <grpcpp/client_context.h>
+#include <grpcpp/impl/rpc_method.h>
+#include <grpcpp/support/async_stream.h>
+#include <grpcpp/support/async_unary_call.h>
+#include <grpcpp/support/byte_buffer.h>
+#include <grpcpp/support/client_callback.h>
+#include <grpcpp/support/status.h>
+#include <grpcpp/support/stub_options.h>
+
+namespace grpc {
+
+class CompletionQueue;
+
+typedef ClientAsyncReaderWriter<ByteBuffer, ByteBuffer>
+    GenericClientAsyncReaderWriter;
+typedef ClientAsyncResponseReader<ByteBuffer> GenericClientAsyncResponseReader;
+
+/// Generic stubs provide a type-unaware interface to call gRPC methods
+/// by name. In practice, the Request and Response types should be basic
+/// types like grpc::ByteBuffer or proto::MessageLite (the base protobuf).
+template <class RequestType, class ResponseType>
+class TemplatedGenericStub final {
+ public:
+  explicit TemplatedGenericStub(std::shared_ptr<grpc::ChannelInterface> channel)
+      : channel_(channel) {}
+
+  /// Setup a call to a named method \a method using \a context, but don't
+  /// start it. Let it be started explicitly with StartCall and a tag.
+  /// The return value only indicates whether or not registration of the call
+  /// succeeded (i.e. the call won't proceed if the return value is nullptr).
+  std::unique_ptr<ClientAsyncReaderWriter<RequestType, ResponseType>>
+  PrepareCall(ClientContext* context, const std::string& method,
+              grpc::CompletionQueue* cq) {
+    return CallInternal(channel_.get(), context, method, /*options=*/{}, cq,
+                        false, nullptr);
+  }
+
+  /// Setup a unary call to a named method \a method using \a context, and don't
+  /// start it. Let it be started explicitly with StartCall.
+  /// The return value only indicates whether or not registration of the call
+  /// succeeded (i.e. the call won't proceed if the return value is nullptr).
+  std::unique_ptr<ClientAsyncResponseReader<ResponseType>> PrepareUnaryCall(
+      ClientContext* context, const std::string& method,
+      const RequestType& request, grpc::CompletionQueue* cq) {
+    return std::unique_ptr<ClientAsyncResponseReader<ResponseType>>(
+        internal::ClientAsyncResponseReaderHelper::Create<ResponseType>(
+            channel_.get(), cq,
+            grpc::internal::RpcMethod(method.c_str(),
+                                      /*suffix_for_stats=*/nullptr,
+                                      grpc::internal::RpcMethod::NORMAL_RPC),
+            context, request));
+  }
+
+  /// DEPRECATED for multi-threaded use
+  /// Begin a call to a named method \a method using \a context.
+  /// A tag \a tag will be delivered to \a cq when the call has been started
+  /// (i.e, initial metadata has been sent).
+  /// The return value only indicates whether or not registration of the call
+  /// succeeded (i.e. the call won't proceed if the return value is nullptr).
+  std::unique_ptr<ClientAsyncReaderWriter<RequestType, ResponseType>> Call(
+      ClientContext* context, const std::string& method,
+      grpc::CompletionQueue* cq, void* tag) {
+    return CallInternal(channel_.get(), context, method, /*options=*/{}, cq,
+                        true, tag);
+  }
+
+  /// Setup and start a unary call to a named method \a method using
+  /// \a context and specifying the \a request and \a response buffers.
+  void UnaryCall(ClientContext* context, const std::string& method,
+                 StubOptions options, const RequestType* request,
+                 ResponseType* response,
+                 std::function<void(grpc::Status)> on_completion) {
+    UnaryCallInternal(context, method, options, request, response,
+                      std::move(on_completion));
+  }
+
+  /// Setup a unary call to a named method \a method using
+  /// \a context and specifying the \a request and \a response buffers.
+  /// Like any other reactor-based RPC, it will not be activated until
+  /// StartCall is invoked on its reactor.
+  void PrepareUnaryCall(ClientContext* context, const std::string& method,
+                        StubOptions options, const RequestType* request,
+                        ResponseType* response, ClientUnaryReactor* reactor) {
+    PrepareUnaryCallInternal(context, method, options, request, response,
+                             reactor);
+  }
+
+  /// Setup a call to a named method \a method using \a context and tied to
+  /// \a reactor . Like any other bidi streaming RPC, it will not be activated
+  /// until StartCall is invoked on its reactor.
+  void PrepareBidiStreamingCall(
+      ClientContext* context, const std::string& method, StubOptions options,
+      ClientBidiReactor<RequestType, ResponseType>* reactor) {
+    PrepareBidiStreamingCallInternal(context, method, options, reactor);
+  }
+
+ private:
+  std::shared_ptr<grpc::ChannelInterface> channel_;
+
+  void UnaryCallInternal(ClientContext* context, const std::string& method,
+                         StubOptions options, const RequestType* request,
+                         ResponseType* response,
+                         std::function<void(grpc::Status)> on_completion) {
+    internal::CallbackUnaryCall(
+        channel_.get(),
+        grpc::internal::RpcMethod(method.c_str(), options.suffix_for_stats(),
+                                  grpc::internal::RpcMethod::NORMAL_RPC),
+        context, request, response, std::move(on_completion));
+  }
+
+  void PrepareUnaryCallInternal(ClientContext* context,
+                                const std::string& method, StubOptions options,
+                                const RequestType* request,
+                                ResponseType* response,
+                                ClientUnaryReactor* reactor) {
+    internal::ClientCallbackUnaryFactory::Create<RequestType, ResponseType>(
+        channel_.get(),
+        grpc::internal::RpcMethod(method.c_str(), options.suffix_for_stats(),
+                                  grpc::internal::RpcMethod::NORMAL_RPC),
+        context, request, response, reactor);
+  }
+
+  void PrepareBidiStreamingCallInternal(
+      ClientContext* context, const std::string& method, StubOptions options,
+      ClientBidiReactor<RequestType, ResponseType>* reactor) {
+    internal::ClientCallbackReaderWriterFactory<RequestType, ResponseType>::
+        Create(channel_.get(),
+               grpc::internal::RpcMethod(
+                   method.c_str(), options.suffix_for_stats(),
+                   grpc::internal::RpcMethod::BIDI_STREAMING),
+               context, reactor);
+  }
+
+  std::unique_ptr<ClientAsyncReaderWriter<RequestType, ResponseType>>
+  CallInternal(grpc::ChannelInterface* channel, ClientContext* context,
+               const std::string& method, StubOptions options,
+               grpc::CompletionQueue* cq, bool start, void* tag) {
+    return std::unique_ptr<ClientAsyncReaderWriter<RequestType, ResponseType>>(
+        internal::ClientAsyncReaderWriterFactory<RequestType, ResponseType>::
+            Create(channel, cq,
+                   grpc::internal::RpcMethod(
+                       method.c_str(), options.suffix_for_stats(),
+                       grpc::internal::RpcMethod::BIDI_STREAMING),
+                   context, start, tag));
+  }
+};
+
+typedef TemplatedGenericStub<grpc::ByteBuffer, grpc::ByteBuffer> GenericStub;
+
+}  // namespace grpc
+
+#endif  // GRPCPP_GENERIC_GENERIC_STUB_H