GRPC C++  1.39.1
client_unary_call.h
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1 /*
2  *
3  * Copyright 2015 gRPC authors.
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5  * Licensed under the Apache License, Version 2.0 (the "License");
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18 
19 #ifndef GRPCPP_IMPL_CODEGEN_CLIENT_UNARY_CALL_H
20 #define GRPCPP_IMPL_CODEGEN_CLIENT_UNARY_CALL_H
21 
28 
29 namespace grpc {
30 
31 class ClientContext;
32 namespace internal {
33 class RpcMethod;
34 
40 template <class InputMessage, class OutputMessage,
41  class BaseInputMessage = InputMessage,
42  class BaseOutputMessage = OutputMessage>
44  grpc::ClientContext* context,
45  const InputMessage& request, OutputMessage* result) {
46  static_assert(std::is_base_of<BaseInputMessage, InputMessage>::value,
47  "Invalid input message specification");
48  static_assert(std::is_base_of<BaseOutputMessage, OutputMessage>::value,
49  "Invalid output message specification");
51  channel, method, context, request, result)
52  .status();
53 }
54 
55 template <class InputMessage, class OutputMessage>
57  public:
59  grpc::ClientContext* context,
60  const InputMessage& request, OutputMessage* result) {
63  nullptr}); // Pluckable completion queue
64  ::grpc::internal::Call call(channel->CreateCall(method, context, &cq));
68  ops;
69  status_ = ops.SendMessagePtr(&request);
70  if (!status_.ok()) {
71  return;
72  }
73  ops.SendInitialMetadata(&context->send_initial_metadata_,
74  context->initial_metadata_flags());
75  ops.RecvInitialMetadata(context);
76  ops.RecvMessage(result);
77  ops.AllowNoMessage();
78  ops.ClientSendClose();
79  ops.ClientRecvStatus(context, &status_);
80  call.PerformOps(&ops);
81  cq.Pluck(&ops);
82  // Some of the ops might fail. If the ops fail in the core layer, status
83  // would reflect the error. But, if the ops fail in the C++ layer, the
84  // status would still be the same as the one returned by gRPC Core. This can
85  // happen if deserialization of the message fails.
86  // TODO(yashykt): If deserialization fails, but the status received is OK,
87  // then it might be a good idea to change the status to something better
88  // than StatusCode::UNIMPLEMENTED to reflect this.
89  if (!ops.got_message && status_.ok()) {
91  "No message returned for unary request");
92  }
93  }
94  Status status() { return status_; }
95 
96  private:
97  Status status_;
98 };
99 
100 } // namespace internal
101 } // namespace grpc
102 
103 #endif // GRPCPP_IMPL_CODEGEN_CLIENT_UNARY_CALL_H
Codegen interface for grpc::Channel.
Definition: channel_interface.h:71
A ClientContext allows the person implementing a service client to:
Definition: client_context.h:193
A thin wrapper around grpc_completion_queue (see src/core/lib/surface/completion_queue....
Definition: completion_queue.h:102
Did it work? If it didn't, why?
Definition: status.h:31
bool ok() const
Is the status OK?
Definition: status.h:118
Definition: client_unary_call.h:56
BlockingUnaryCallImpl(ChannelInterface *channel, const RpcMethod &method, grpc::ClientContext *context, const InputMessage &request, OutputMessage *result)
Definition: client_unary_call.h:58
Status status()
Definition: client_unary_call.h:94
Straightforward wrapping of the C call object.
Definition: call.h:35
Definition: call_op_set.h:769
Definition: call_op_set.h:619
Definition: call_op_set.h:721
Definition: call_op_set.h:424
Definition: call_op_set.h:212
Definition: call_op_set.h:282
Primary implementation of CallOpSetInterface.
Definition: call_op_set.h:867
Descriptor of an RPC method.
Definition: rpc_method.h:29
@ GRPC_CQ_PLUCK
Events are popped out by calling grpc_completion_queue_pluck() API ONLY.
Definition: grpc_types.h:747
#define GRPC_CQ_CURRENT_VERSION
Definition: grpc_types.h:776
@ GRPC_CQ_DEFAULT_POLLING
The completion queue will have an associated pollset and there is no restriction on the type of file ...
Definition: grpc_types.h:727
Status BlockingUnaryCall(ChannelInterface *channel, const RpcMethod &method, grpc::ClientContext *context, const InputMessage &request, OutputMessage *result)
Wrapper that performs a blocking unary call.
Definition: client_unary_call.h:43
::google::protobuf::util::Status Status
Definition: config_protobuf.h:91
An Alarm posts the user-provided tag to its associated completion queue or invokes the user-provided ...
Definition: alarm.h:33
@ UNIMPLEMENTED
Operation is not implemented or not supported/enabled in this service.
Definition: status_code_enum.h:115
Definition: grpc_types.h:778