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/*
*
* Copyright 2015, 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.
*
*/
#ifndef GRPCXX_COMPLETION_QUEUE_H
#define GRPCXX_COMPLETION_QUEUE_H
#include <chrono>
#include <grpc++/impl/client_unary_call.h>
struct grpc_completion_queue;
namespace grpc {
template <class R>
class ClientReader;
template <class W>
class ClientWriter;
template <class R, class W>
class ClientReaderWriter;
template <class R>
class ServerReader;
template <class W>
class ServerWriter;
template <class R, class W>
class ServerReaderWriter;
class CompletionQueue;
class Server;
class ServerContext;
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;
};
// grpc_completion_queue wrapper class
class CompletionQueue {
public:
CompletionQueue();
explicit CompletionQueue(grpc_completion_queue* take);
~CompletionQueue();
// Tri-state return for AsyncNext: SHUTDOWN, GOT_EVENT, TIMEOUT
enum NextStatus { SHUTDOWN, GOT_EVENT, TIMEOUT };
// Nonblocking (until deadline) read from queue.
// Cannot rely on result of tag or ok if return is TIMEOUT
NextStatus AsyncNext(void** tag, bool* ok,
std::chrono::system_clock::time_point deadline);
// Blocking (until deadline) read from queue.
// Returns false if the queue is ready for destruction, true if event
bool Next(void** tag, bool* ok) {
return (AsyncNext(tag, ok, std::chrono::system_clock::time_point::max()) !=
SHUTDOWN);
}
// Shutdown has to be called, and the CompletionQueue can only be
// destructed when false is returned from Next().
void Shutdown();
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 R, class W>
friend class ::grpc::ClientReaderWriter;
template <class R>
friend class ::grpc::ServerReader;
template <class W>
friend class ::grpc::ServerWriter;
template <class R, class W>
friend class ::grpc::ServerReaderWriter;
friend class ::grpc::Server;
friend class ::grpc::ServerContext;
friend Status BlockingUnaryCall(ChannelInterface* channel,
const RpcMethod& method,
ClientContext* context,
const grpc::protobuf::Message& request,
grpc::protobuf::Message* result);
// Wraps grpc_completion_queue_pluck.
// Cannot be mixed with calls to Next().
bool Pluck(CompletionQueueTag* tag);
// Does a single polling pluck on tag
void TryPluck(CompletionQueueTag* tag);
grpc_completion_queue* cq_; // owned
};
} // namespace grpc
#endif // GRPCXX_COMPLETION_QUEUE_H
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