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+/*
+ *
+ * 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
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+/// A completion queue implements a concurrent producer-consumer queue, with two
+/// main methods, \a Next and \a AsyncNext.
+#ifndef GRPCXX_IMPL_CODEGEN_COMPLETION_QUEUE_H
+#define GRPCXX_IMPL_CODEGEN_COMPLETION_QUEUE_H
+
+#include <grpc++/impl/codegen/grpc_library.h>
+#include <grpc++/impl/codegen/status.h>
+#include <grpc++/impl/codegen/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 : private 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();
+
+ /// 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
+};
+
+/// 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_IMPL_CODEGEN_COMPLETION_QUEUE_H