| /* |
| * |
| * Copyright 2015-2016, 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 |
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| * |
| */ |
| |
| /// A completion queue implements a concurrent producer-consumer queue, with two |
| /// main methods, \a Next and \a AsyncNext. |
| #ifndef GRPCXX_COMPLETION_QUEUE_H |
| #define GRPCXX_COMPLETION_QUEUE_H |
| |
| #include <grpc/support/time.h> |
| #include <grpc++/impl/grpc_library.h> |
| #include <grpc++/support/status.h> |
| #include <grpc++/support/time.h> |
| |
| struct grpc_completion_queue; |
| |
| namespace grpc { |
| |
| template <class R> |
| class ClientReader; |
| template <class W> |
| class ClientWriter; |
| template <class W, class R> |
| class ClientReaderWriter; |
| template <class R> |
| class ServerReader; |
| template <class W> |
| class ServerWriter; |
| template <class W, class R> |
| class ServerReaderWriter; |
| template <class ServiceType, class RequestType, class ResponseType> |
| class RpcMethodHandler; |
| template <class ServiceType, class RequestType, class ResponseType> |
| class ClientStreamingHandler; |
| template <class ServiceType, class RequestType, class ResponseType> |
| class ServerStreamingHandler; |
| template <class ServiceType, class RequestType, class ResponseType> |
| class BidiStreamingHandler; |
| class UnknownMethodHandler; |
| |
| class Channel; |
| class ChannelInterface; |
| class ClientContext; |
| class CompletionQueueTag; |
| class CompletionQueue; |
| class RpcMethod; |
| class Server; |
| class ServerBuilder; |
| class ServerContext; |
| |
| /// A thin wrapper around \a grpc_completion_queue (see / \a |
| /// src/core/surface/completion_queue.h). |
| class CompletionQueue : public GrpcLibrary { |
| public: |
| /// Default constructor. Implicitly creates a \a grpc_completion_queue |
| /// instance. |
| CompletionQueue(); |
| |
| /// Wrap \a take, taking ownership of the instance. |
| /// |
| /// \param take The completion queue instance to wrap. Ownership is taken. |
| explicit CompletionQueue(grpc_completion_queue* take); |
| |
| /// Destructor. Destroys the owned wrapped completion queue / instance. |
| ~CompletionQueue() GRPC_OVERRIDE; |
| |
| /// Tri-state return for AsyncNext: SHUTDOWN, GOT_EVENT, TIMEOUT. |
| enum NextStatus { |
| SHUTDOWN, ///< The completion queue has been shutdown. |
| GOT_EVENT, ///< Got a new event; \a tag will be filled in with its |
| ///< associated value; \a ok indicating its success. |
| TIMEOUT ///< deadline was reached. |
| }; |
| |
| /// Read from the queue, blocking up to \a deadline (or the queue's shutdown). |
| /// Both \a tag and \a ok are updated upon success (if an event is available |
| /// within the \a deadline). A \a tag points to an arbitrary location usually |
| /// employed to uniquely identify an event. |
| /// |
| /// \param tag[out] Upon sucess, updated to point to the event's tag. |
| /// \param ok[out] Upon sucess, true if read a regular event, false otherwise. |
| /// \param deadline[in] How long to block in wait for an event. |
| /// |
| /// \return The type of event read. |
| template <typename T> |
| NextStatus AsyncNext(void** tag, bool* ok, const T& deadline) { |
| TimePoint<T> deadline_tp(deadline); |
| return AsyncNextInternal(tag, ok, deadline_tp.raw_time()); |
| } |
| |
| /// Read from the queue, blocking until an event is available or the queue is |
| /// shutting down. |
| /// |
| /// \param tag[out] Updated to point to the read event's tag. |
| /// \param ok[out] true if read a regular event, false otherwise. |
| /// |
| /// \return true if read a regular event, false if the queue is shutting down. |
| bool Next(void** tag, bool* ok) { |
| return (AsyncNextInternal(tag, ok, gpr_inf_future(GPR_CLOCK_REALTIME)) != |
| SHUTDOWN); |
| } |
| |
| /// Request the shutdown of the queue. |
| /// |
| /// \warning This method must be called at some point. Once invoked, \a Next |
| /// will start to return false and \a AsyncNext will return \a |
| /// NextStatus::SHUTDOWN. Only once either one of these methods does that |
| /// (that is, once the queue has been \em drained) can an instance of this |
| /// class be destroyed. |
| void Shutdown(); |
| |
| /// Returns a \em raw pointer to the underlying \a grpc_completion_queue |
| /// instance. |
| /// |
| /// \warning Remember that the returned instance is owned. No transfer of |
| /// owership is performed. |
| grpc_completion_queue* cq() { return cq_; } |
| |
| private: |
| // Friend synchronous wrappers so that they can access Pluck(), which is |
| // a semi-private API geared towards the synchronous implementation. |
| template <class R> |
| friend class ::grpc::ClientReader; |
| template <class W> |
| friend class ::grpc::ClientWriter; |
| template <class W, class R> |
| friend class ::grpc::ClientReaderWriter; |
| template <class R> |
| friend class ::grpc::ServerReader; |
| template <class W> |
| friend class ::grpc::ServerWriter; |
| template <class W, class R> |
| friend class ::grpc::ServerReaderWriter; |
| template <class ServiceType, class RequestType, class ResponseType> |
| friend class RpcMethodHandler; |
| template <class ServiceType, class RequestType, class ResponseType> |
| friend class ClientStreamingHandler; |
| template <class ServiceType, class RequestType, class ResponseType> |
| friend class ServerStreamingHandler; |
| template <class ServiceType, class RequestType, class ResponseType> |
| friend class BidiStreamingHandler; |
| friend class UnknownMethodHandler; |
| friend class ::grpc::Server; |
| friend class ::grpc::ServerContext; |
| template <class InputMessage, class OutputMessage> |
| friend Status BlockingUnaryCall(ChannelInterface* channel, const RpcMethod& method, |
| ClientContext* context, |
| const InputMessage& request, |
| OutputMessage* result); |
| |
| NextStatus AsyncNextInternal(void** tag, bool* ok, gpr_timespec deadline); |
| |
| /// Wraps \a grpc_completion_queue_pluck. |
| /// \warning Must not be mixed with calls to \a Next. |
| bool Pluck(CompletionQueueTag* tag); |
| |
| /// Performs a single polling pluck on \a tag. |
| void TryPluck(CompletionQueueTag* tag); |
| |
| grpc_completion_queue* cq_; // owned |
| }; |
| |
| /// An interface allowing implementors to process and filter event tags. |
| class CompletionQueueTag { |
| public: |
| virtual ~CompletionQueueTag() {} |
| // Called prior to returning from Next(), return value is the status of the |
| // operation (return status is the default thing to do). If this function |
| // returns false, the tag is dropped and not returned from the completion |
| // queue |
| virtual bool FinalizeResult(void** tag, bool* status) = 0; |
| }; |
| |
| /// A specific type of completion queue used by the processing of notifications |
| /// by servers. Instantiated by \a ServerBuilder. |
| class ServerCompletionQueue : public CompletionQueue { |
| private: |
| friend class ServerBuilder; |
| ServerCompletionQueue() {} |
| }; |
| |
| } // namespace grpc |
| |
| #endif // GRPCXX_COMPLETION_QUEUE_H |