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The C based gRPC (C++, Python, Ruby, Objective-C, PHP, C#)
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517 lines
18 KiB
517 lines
18 KiB
/* |
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* |
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* Copyright 2015 gRPC authors. |
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* |
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* Licensed under the Apache License, Version 2.0 (the "License"); |
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* you may not use this file except in compliance with the License. |
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* You may obtain a copy of the License at |
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* |
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* http://www.apache.org/licenses/LICENSE-2.0 |
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* |
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* Unless required by applicable law or agreed to in writing, software |
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* distributed under the License is distributed on an "AS IS" BASIS, |
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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* See the License for the specific language governing permissions and |
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* limitations under the License. |
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* |
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*/ |
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/// A ClientContext allows the person implementing a service client to: |
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/// |
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/// - Add custom metadata key-value pairs that will propagated to the server |
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/// side. |
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/// - Control call settings such as compression and authentication. |
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/// - Initial and trailing metadata coming from the server. |
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/// - Get performance metrics (ie, census). |
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/// |
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/// Context settings are only relevant to the call they are invoked with, that |
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/// is to say, they aren't sticky. Some of these settings, such as the |
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/// compression options, can be made persistent at channel construction time |
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/// (see \a grpc::CreateCustomChannel). |
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/// |
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/// \warning ClientContext instances should \em not be reused across rpcs. |
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#ifndef GRPCPP_CLIENT_CONTEXT_H |
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#define GRPCPP_CLIENT_CONTEXT_H |
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#include <map> |
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#include <memory> |
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#include <string> |
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#include <grpc/impl/codegen/compression_types.h> |
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#include <grpc/impl/codegen/propagation_bits.h> |
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#include <grpcpp/impl/codegen/core_codegen_interface.h> |
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#include <grpcpp/impl/codegen/create_auth_context.h> |
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#include <grpcpp/impl/codegen/metadata_map.h> |
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#include <grpcpp/impl/codegen/sync.h> |
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#include <grpcpp/impl/rpc_method.h> |
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#include <grpcpp/security/auth_context.h> |
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#include <grpcpp/support/client_interceptor.h> |
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#include <grpcpp/support/config.h> |
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#include <grpcpp/support/slice.h> |
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#include <grpcpp/support/status.h> |
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#include <grpcpp/support/string_ref.h> |
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#include <grpcpp/support/time.h> |
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struct census_context; |
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struct grpc_call; |
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namespace grpc { |
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class ServerContext; |
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class ServerContextBase; |
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class CallbackServerContext; |
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namespace internal { |
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template <class InputMessage, class OutputMessage> |
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class CallbackUnaryCallImpl; |
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template <class Request, class Response> |
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class ClientCallbackReaderWriterImpl; |
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template <class Response> |
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class ClientCallbackReaderImpl; |
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template <class Request> |
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class ClientCallbackWriterImpl; |
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class ClientCallbackUnaryImpl; |
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class ClientContextAccessor; |
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class ClientAsyncResponseReaderHelper; |
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} // namespace internal |
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template <class R> |
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class ClientReader; |
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template <class W> |
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class ClientWriter; |
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template <class W, class R> |
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class ClientReaderWriter; |
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template <class R> |
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class ClientAsyncReader; |
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template <class W> |
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class ClientAsyncWriter; |
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template <class W, class R> |
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class ClientAsyncReaderWriter; |
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template <class R> |
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class ClientAsyncResponseReader; |
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namespace testing { |
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class InteropClientContextInspector; |
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class ClientContextTestPeer; |
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} // namespace testing |
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namespace internal { |
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class RpcMethod; |
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template <class InputMessage, class OutputMessage> |
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class BlockingUnaryCallImpl; |
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class CallOpClientRecvStatus; |
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class CallOpRecvInitialMetadata; |
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class ServerContextImpl; |
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template <class InputMessage, class OutputMessage> |
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class CallbackUnaryCallImpl; |
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template <class Request, class Response> |
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class ClientCallbackReaderWriterImpl; |
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template <class Response> |
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class ClientCallbackReaderImpl; |
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template <class Request> |
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class ClientCallbackWriterImpl; |
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class ClientCallbackUnaryImpl; |
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class ClientContextAccessor; |
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} // namespace internal |
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class CallCredentials; |
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class Channel; |
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class ChannelInterface; |
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class CompletionQueue; |
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/// Options for \a ClientContext::FromServerContext specifying which traits from |
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/// the \a ServerContext to propagate (copy) from it into a new \a |
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/// ClientContext. |
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/// |
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/// \see ClientContext::FromServerContext |
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class PropagationOptions { |
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public: |
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PropagationOptions() : propagate_(GRPC_PROPAGATE_DEFAULTS) {} |
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PropagationOptions& enable_deadline_propagation() { |
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propagate_ |= GRPC_PROPAGATE_DEADLINE; |
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return *this; |
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} |
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PropagationOptions& disable_deadline_propagation() { |
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propagate_ &= ~GRPC_PROPAGATE_DEADLINE; |
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return *this; |
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} |
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PropagationOptions& enable_census_stats_propagation() { |
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propagate_ |= GRPC_PROPAGATE_CENSUS_STATS_CONTEXT; |
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return *this; |
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} |
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PropagationOptions& disable_census_stats_propagation() { |
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propagate_ &= ~GRPC_PROPAGATE_CENSUS_STATS_CONTEXT; |
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return *this; |
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} |
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PropagationOptions& enable_census_tracing_propagation() { |
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propagate_ |= GRPC_PROPAGATE_CENSUS_TRACING_CONTEXT; |
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return *this; |
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} |
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PropagationOptions& disable_census_tracing_propagation() { |
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propagate_ &= ~GRPC_PROPAGATE_CENSUS_TRACING_CONTEXT; |
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return *this; |
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} |
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PropagationOptions& enable_cancellation_propagation() { |
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propagate_ |= GRPC_PROPAGATE_CANCELLATION; |
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return *this; |
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} |
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PropagationOptions& disable_cancellation_propagation() { |
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propagate_ &= ~GRPC_PROPAGATE_CANCELLATION; |
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return *this; |
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} |
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uint32_t c_bitmask() const { return propagate_; } |
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private: |
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uint32_t propagate_; |
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}; |
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/// A ClientContext allows the person implementing a service client to: |
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/// |
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/// - Add custom metadata key-value pairs that will propagated to the server |
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/// side. |
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/// - Control call settings such as compression and authentication. |
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/// - Initial and trailing metadata coming from the server. |
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/// - Get performance metrics (ie, census). |
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/// |
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/// Context settings are only relevant to the call they are invoked with, that |
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/// is to say, they aren't sticky. Some of these settings, such as the |
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/// compression options, can be made persistent at channel construction time |
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/// (see \a grpc::CreateCustomChannel). |
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/// |
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/// \warning ClientContext instances should \em not be reused across rpcs. |
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/// \warning The ClientContext instance used for creating an rpc must remain |
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/// alive and valid for the lifetime of the rpc. |
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class ClientContext { |
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public: |
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ClientContext(); |
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~ClientContext(); |
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/// Create a new \a ClientContext as a child of an incoming server call, |
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/// according to \a options (\see PropagationOptions). |
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/// |
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/// \param server_context The source server context to use as the basis for |
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/// constructing the client context. |
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/// \param options The options controlling what to copy from the \a |
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/// server_context. |
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/// |
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/// \return A newly constructed \a ClientContext instance based on \a |
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/// server_context, with traits propagated (copied) according to \a options. |
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static std::unique_ptr<ClientContext> FromServerContext( |
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const grpc::ServerContextBase& server_context, |
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PropagationOptions options = PropagationOptions()); |
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static std::unique_ptr<ClientContext> FromCallbackServerContext( |
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const grpc::CallbackServerContext& server_context, |
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PropagationOptions options = PropagationOptions()); |
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/// Add the (\a meta_key, \a meta_value) pair to the metadata associated with |
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/// a client call. These are made available at the server side by the \a |
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/// grpc::ServerContext::client_metadata() method. |
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/// |
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/// \warning This method should only be called before invoking the rpc. |
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/// |
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/// \param meta_key The metadata key. If \a meta_value is binary data, it must |
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/// end in "-bin". |
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/// \param meta_value The metadata value. If its value is binary, the key name |
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/// must end in "-bin". |
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/// |
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/// Metadata must conform to the following format: |
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/** |
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\verbatim |
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Custom-Metadata -> Binary-Header / ASCII-Header |
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Binary-Header -> {Header-Name "-bin" } {binary value} |
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ASCII-Header -> Header-Name ASCII-Value |
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Header-Name -> 1*( %x30-39 / %x61-7A / "_" / "-" / ".") ; 0-9 a-z _ - . |
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ASCII-Value -> 1*( %x20-%x7E ) ; space and printable ASCII |
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Custom-Metadata -> Binary-Header / ASCII-Header |
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\endverbatim |
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**/ |
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void AddMetadata(const std::string& meta_key, const std::string& meta_value); |
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/// Return a collection of initial metadata key-value pairs. Note that keys |
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/// may happen more than once (ie, a \a std::multimap is returned). |
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/// |
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/// \warning This method should only be called after initial metadata has been |
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/// received. For streaming calls, see \a |
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/// ClientReaderInterface::WaitForInitialMetadata(). |
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/// |
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/// \return A multimap of initial metadata key-value pairs from the server. |
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const std::multimap<grpc::string_ref, grpc::string_ref>& |
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GetServerInitialMetadata() const { |
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GPR_CODEGEN_ASSERT(initial_metadata_received_); |
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return *recv_initial_metadata_.map(); |
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} |
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/// Return a collection of trailing metadata key-value pairs. Note that keys |
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/// may happen more than once (ie, a \a std::multimap is returned). |
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/// |
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/// \warning This method is only callable once the stream has finished. |
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/// |
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/// \return A multimap of metadata trailing key-value pairs from the server. |
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const std::multimap<grpc::string_ref, grpc::string_ref>& |
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GetServerTrailingMetadata() const { |
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// TODO(yangg) check finished |
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return *trailing_metadata_.map(); |
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} |
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/// Set the deadline for the client call. |
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/// |
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/// \warning This method should only be called before invoking the rpc. |
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/// |
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/// \param deadline the deadline for the client call. Units are determined by |
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/// the type used. The deadline is an absolute (not relative) time. |
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template <typename T> |
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void set_deadline(const T& deadline) { |
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grpc::TimePoint<T> deadline_tp(deadline); |
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deadline_ = deadline_tp.raw_time(); |
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} |
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/// Trigger wait-for-ready or not on this request. |
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/// See https://github.com/grpc/grpc/blob/master/doc/wait-for-ready.md. |
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/// If set, if an RPC is made when a channel's connectivity state is |
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/// TRANSIENT_FAILURE or CONNECTING, the call will not "fail fast", |
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/// and the channel will wait until the channel is READY before making the |
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/// call. |
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void set_wait_for_ready(bool wait_for_ready) { |
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wait_for_ready_ = wait_for_ready; |
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wait_for_ready_explicitly_set_ = true; |
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} |
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/// DEPRECATED: Use set_wait_for_ready() instead. |
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void set_fail_fast(bool fail_fast) { set_wait_for_ready(!fail_fast); } |
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/// Return the deadline for the client call. |
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std::chrono::system_clock::time_point deadline() const { |
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return grpc::Timespec2Timepoint(deadline_); |
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} |
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/// Return a \a gpr_timespec representation of the client call's deadline. |
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gpr_timespec raw_deadline() const { return deadline_; } |
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/// Set the per call authority header (see |
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/// https://tools.ietf.org/html/rfc7540#section-8.1.2.3). |
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void set_authority(const std::string& authority) { authority_ = authority; } |
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/// Return the authentication context for the associated client call. |
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/// It is only valid to call this during the lifetime of the client call. |
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/// |
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/// \see grpc::AuthContext. |
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std::shared_ptr<const grpc::AuthContext> auth_context() const { |
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if (auth_context_ == nullptr) { |
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auth_context_ = grpc::CreateAuthContext(call_); |
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} |
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return auth_context_; |
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} |
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/// Set credentials for the client call. |
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/// |
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/// A credentials object encapsulates all the state needed by a client to |
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/// authenticate with a server and make various assertions, e.g., about the |
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/// client’s identity, role, or whether it is authorized to make a particular |
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/// call. |
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/// |
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/// It is legal to call this only before initial metadata is sent. |
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/// |
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/// \see https://grpc.io/docs/guides/auth.html |
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void set_credentials(const std::shared_ptr<grpc::CallCredentials>& creds); |
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/// EXPERIMENTAL debugging API |
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/// |
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/// Returns the credentials for the client call. This should be used only in |
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/// tests and for diagnostic purposes, and should not be used by application |
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/// logic. |
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std::shared_ptr<grpc::CallCredentials> credentials() { return creds_; } |
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/// Return the compression algorithm the client call will request be used. |
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/// Note that the gRPC runtime may decide to ignore this request, for example, |
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/// due to resource constraints. |
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grpc_compression_algorithm compression_algorithm() const { |
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return compression_algorithm_; |
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} |
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/// Set \a algorithm to be the compression algorithm used for the client call. |
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/// |
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/// \param algorithm The compression algorithm used for the client call. |
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void set_compression_algorithm(grpc_compression_algorithm algorithm); |
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/// Flag whether the initial metadata should be \a corked |
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/// |
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/// If \a corked is true, then the initial metadata will be coalesced with the |
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/// write of first message in the stream. As a result, any tag set for the |
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/// initial metadata operation (starting a client-streaming or bidi-streaming |
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/// RPC) will not actually be sent to the completion queue or delivered |
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/// via Next. |
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/// |
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/// \param corked The flag indicating whether the initial metadata is to be |
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/// corked or not. |
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void set_initial_metadata_corked(bool corked) { |
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initial_metadata_corked_ = corked; |
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} |
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/// Return the peer uri in a string. |
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/// It is only valid to call this during the lifetime of the client call. |
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/// |
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/// \warning This value is never authenticated or subject to any security |
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/// related code. It must not be used for any authentication related |
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/// functionality. Instead, use auth_context. |
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/// |
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/// \return The call's peer URI. |
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std::string peer() const; |
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/// Sets the census context. |
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/// It is only valid to call this before the client call is created. A common |
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/// place of setting census context is from within the DefaultConstructor |
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/// method of GlobalCallbacks. |
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void set_census_context(struct census_context* ccp) { census_context_ = ccp; } |
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/// Returns the census context that has been set, or nullptr if not set. |
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struct census_context* census_context() const { return census_context_; } |
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/// Send a best-effort out-of-band cancel on the call associated with |
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/// this client context. The call could be in any stage; e.g., if it is |
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/// already finished, it may still return success. |
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/// |
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/// There is no guarantee the call will be cancelled. |
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/// |
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/// Note that TryCancel() does not change any of the tags that are pending |
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/// on the completion queue. All pending tags will still be delivered |
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/// (though their ok result may reflect the effect of cancellation). |
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/// |
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/// This method is thread-safe, and can be called multiple times from any |
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/// thread. |
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void TryCancel(); |
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/// Global Callbacks |
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/// |
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/// Can be set exactly once per application to install hooks whenever |
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/// a client context is constructed and destructed. |
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class GlobalCallbacks { |
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public: |
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virtual ~GlobalCallbacks() {} |
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virtual void DefaultConstructor(ClientContext* context) = 0; |
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virtual void Destructor(ClientContext* context) = 0; |
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}; |
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static void SetGlobalCallbacks(GlobalCallbacks* callbacks); |
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/// Should be used for framework-level extensions only. |
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/// Applications never need to call this method. |
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grpc_call* c_call() { return call_; } |
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/// EXPERIMENTAL debugging API |
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/// |
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/// if status is not ok() for an RPC, this will return a detailed string |
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/// of the gRPC Core error that led to the failure. It should not be relied |
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/// upon for anything other than gaining more debug data in failure cases. |
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std::string debug_error_string() const { return debug_error_string_; } |
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private: |
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// Disallow copy and assign. |
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ClientContext(const ClientContext&); |
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ClientContext& operator=(const ClientContext&); |
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friend class grpc::testing::InteropClientContextInspector; |
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friend class grpc::testing::ClientContextTestPeer; |
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friend class grpc::internal::CallOpClientRecvStatus; |
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friend class grpc::internal::CallOpRecvInitialMetadata; |
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friend class grpc::Channel; |
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template <class R> |
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friend class grpc::ClientReader; |
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template <class W> |
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friend class grpc::ClientWriter; |
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template <class W, class R> |
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friend class grpc::ClientReaderWriter; |
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template <class R> |
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friend class grpc::ClientAsyncReader; |
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template <class W> |
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friend class grpc::ClientAsyncWriter; |
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template <class W, class R> |
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friend class grpc::ClientAsyncReaderWriter; |
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template <class R> |
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friend class grpc::ClientAsyncResponseReader; |
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friend class grpc::internal::ClientAsyncResponseReaderHelper; |
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template <class InputMessage, class OutputMessage> |
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friend class grpc::internal::BlockingUnaryCallImpl; |
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template <class InputMessage, class OutputMessage> |
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friend class grpc::internal::CallbackUnaryCallImpl; |
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template <class Request, class Response> |
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friend class grpc::internal::ClientCallbackReaderWriterImpl; |
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template <class Response> |
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friend class grpc::internal::ClientCallbackReaderImpl; |
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template <class Request> |
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friend class grpc::internal::ClientCallbackWriterImpl; |
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friend class grpc::internal::ClientCallbackUnaryImpl; |
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friend class grpc::internal::ClientContextAccessor; |
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// Used by friend class CallOpClientRecvStatus |
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void set_debug_error_string(const std::string& debug_error_string) { |
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debug_error_string_ = debug_error_string; |
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} |
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grpc_call* call() const { return call_; } |
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void set_call(grpc_call* call, const std::shared_ptr<grpc::Channel>& channel); |
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grpc::experimental::ClientRpcInfo* set_client_rpc_info( |
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const char* method, const char* suffix_for_stats, |
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grpc::internal::RpcMethod::RpcType type, grpc::ChannelInterface* channel, |
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const std::vector<std::unique_ptr< |
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grpc::experimental::ClientInterceptorFactoryInterface>>& creators, |
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size_t interceptor_pos) { |
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rpc_info_ = grpc::experimental::ClientRpcInfo(this, type, method, |
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suffix_for_stats, channel); |
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rpc_info_.RegisterInterceptors(creators, interceptor_pos); |
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return &rpc_info_; |
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} |
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uint32_t initial_metadata_flags() const { |
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return (wait_for_ready_ ? GRPC_INITIAL_METADATA_WAIT_FOR_READY : 0) | |
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(wait_for_ready_explicitly_set_ |
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? GRPC_INITIAL_METADATA_WAIT_FOR_READY_EXPLICITLY_SET |
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: 0); |
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} |
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std::string authority() { return authority_; } |
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void SendCancelToInterceptors(); |
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static std::unique_ptr<ClientContext> FromInternalServerContext( |
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const grpc::ServerContextBase& server_context, |
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PropagationOptions options); |
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bool initial_metadata_received_; |
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bool wait_for_ready_; |
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bool wait_for_ready_explicitly_set_; |
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std::shared_ptr<grpc::Channel> channel_; |
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grpc::internal::Mutex mu_; |
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grpc_call* call_; |
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bool call_canceled_; |
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gpr_timespec deadline_; |
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grpc::string authority_; |
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std::shared_ptr<grpc::CallCredentials> creds_; |
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mutable std::shared_ptr<const grpc::AuthContext> auth_context_; |
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struct census_context* census_context_; |
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std::multimap<std::string, std::string> send_initial_metadata_; |
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mutable grpc::internal::MetadataMap recv_initial_metadata_; |
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mutable grpc::internal::MetadataMap trailing_metadata_; |
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grpc_call* propagate_from_call_; |
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PropagationOptions propagation_options_; |
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grpc_compression_algorithm compression_algorithm_; |
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bool initial_metadata_corked_; |
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std::string debug_error_string_; |
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grpc::experimental::ClientRpcInfo rpc_info_; |
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}; |
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} // namespace grpc |
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#endif // GRPCPP_CLIENT_CONTEXT_H
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