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rocksdb/thrift/lib/cpp/async/TEventConnection.h

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// Copyright (c) 2006- Facebook
// Distributed under the Thrift Software License
//
// See accompanying file LICENSE or visit the Thrift site at:
// http://developers.facebook.com/thrift/
#ifndef THRIFT_ASYNC_TEVENTCONNECTION_H_
#define THRIFT_ASYNC_TEVENTCONNECTION_H_ 1
#include "thrift/lib/cpp/server/TConnectionContext.h"
#include "thrift/lib/cpp/transport/TSocketAddress.h"
#include "thrift/lib/cpp/async/TEventServer.h"
#include <boost/shared_ptr.hpp>
#include <boost/noncopyable.hpp>
namespace apache { namespace thrift {
class TProcessor;
namespace protocol {
class TProtocol;
}
namespace server {
class TServerEventHandler;
}
namespace transport {
class TMemoryBuffer;
}
namespace async {
class TAsyncEventChannel;
class TAsyncProcessor;
class TEventWorker;
class TAsyncSocket;
class TaskCompletionMessage;
/**
* Represents a connection that is handled via libevent. This connection
* essentially encapsulates a socket that has some associated libevent state.
*/
class TEventConnection : private boost::noncopyable,
public TEventBase::LoopCallback {
public:
/**
* Constructor for TEventConnection.
*
* @param asyncSocket shared pointer to the async socket
* @param address the peer address of this connection
* @param worker the worker instance that is handling this connection
*/
TEventConnection(boost::shared_ptr<TAsyncSocket> asyncSocket,
const transport::TSocketAddress* address,
TEventWorker* worker, TEventServer::TransportType transport);
/**
* (Re-)Initialize a TEventConnection. We break this out from the
* constructor to allow for pooling.
*
* @param asyncSocket shared pointer to the async socket
* @param address the peer address of this connection
* @param worker the worker instance that is handling this connection
*/
void init(boost::shared_ptr<TAsyncSocket> asyncSocket,
const transport::TSocketAddress* address,
TEventWorker* worker, TEventServer::TransportType transport);
/// First cause -- starts i/o on connection
void start();
/// Shut down the connection even if it's OK; used for load reduction.
void stop() {
shutdown_ = true;
}
/// Return a pointer to the worker that owns us
TEventWorker* getWorker() const {
return worker_;
}
/// cause the notification callback to occur within the appropriate context
bool notifyCompletion(TaskCompletionMessage &&msg);
/// Run scheduled read when there are too many reads on the stack
void runLoopCallback() THRIFT_NOEXCEPT;
boost::shared_ptr<apache::thrift::TProcessor> getProcessor() const {
return processor_;
}
boost::shared_ptr<apache::thrift::protocol::TProtocol>
getInputProtocol() const {
return inputProtocol_;
}
boost::shared_ptr<apache::thrift::protocol::TProtocol>
getOutputProtocol() const {
return outputProtocol_;
}
/// Get the per-server event handler set for this server, if any
boost::shared_ptr<apache::thrift::server::TServerEventHandler>
getServerEventHandler() const {
return serverEventHandler_;
}
/// Get the TConnectionContext for this connection
server::TConnectionContext* getConnectionContext() {
return &context_;
}
/// Destructor -- close down the connection.
~TEventConnection();
/**
* Check the size of our memory buffers and resize if needed. Do not call
* when a call is in progress.
*/
void checkBufferMemoryUsage();
private:
class ConnContext : public server::TConnectionContext {
public:
void init(const transport::TSocketAddress* address,
boost::shared_ptr<protocol::TProtocol> inputProtocol,
boost::shared_ptr<protocol::TProtocol> outputProtocol) {
address_ = *address;
inputProtocol_ = inputProtocol;
outputProtocol_ = outputProtocol;
}
virtual const transport::TSocketAddress* getPeerAddress() const {
return &address_;
}
void reset() {
address_.reset();
cleanupUserData();
}
// TODO(dsanduleac): implement the virtual getInputProtocol() & such
virtual boost::shared_ptr<protocol::TProtocol> getInputProtocol() const {
// from TEventConnection
return inputProtocol_;
}
virtual boost::shared_ptr<protocol::TProtocol> getOutputProtocol() const {
return outputProtocol_;
}
private:
transport::TSocketAddress address_;
boost::shared_ptr<protocol::TProtocol> inputProtocol_;
boost::shared_ptr<protocol::TProtocol> outputProtocol_;
};
void readNextRequest();
void handleReadSuccess();
void handleReadFailure();
void handleAsyncTaskComplete(bool success);
void handleSendSuccess();
void handleSendFailure();
void handleEOF();
void handleFailure(const char* msg);
void cleanup();
//! The worker instance handling this connection.
TEventWorker* worker_;
//! This connection's socket.
boost::shared_ptr<TAsyncSocket> asyncSocket_;
//! Transport that the processor reads from.
boost::shared_ptr<apache::thrift::transport::TMemoryBuffer> inputTransport_;
//! Transport that the processor writes to.
boost::shared_ptr<apache::thrift::transport::TMemoryBuffer> outputTransport_;
/// Largest size of read buffer seen since buffer was constructed
size_t largestReadBufferSize_;
/// Largest size of write buffer seen since buffer was constructed
size_t largestWriteBufferSize_;
/// Count of the number of calls for use with getResizeBufferEveryN().
int32_t callsForResize_;
//! Protocol decoder.
boost::shared_ptr<apache::thrift::protocol::TProtocol> inputProtocol_;
//! Protocol encoder.
boost::shared_ptr<apache::thrift::protocol::TProtocol> outputProtocol_;
//! Channel that actually performs the socket I/O and callbacks.
TAsyncEventChannel* asyncChannel_;
/// Count of outstanding processor callbacks (generally 0 or 1).
int32_t processorActive_;
//! Count of the number of handleReadSuccess frames on the stack
int32_t readersActive_;
/// Sync processor if we're in queuing mode
boost::shared_ptr<apache::thrift::TProcessor> processor_;
/// Flag used to shut down connection (used for load-shedding mechanism).
bool shutdown_;
/// Flag indicating that we have deferred closing down (processor was active)
bool closing_;
/// The per-server event handler set for this erver, if any
boost::shared_ptr<apache::thrift::server::TServerEventHandler>
serverEventHandler_;
/// per-connection context
ConnContext context_;
/// Our processor
boost::shared_ptr<TAsyncProcessor> asyncProcessor_;
/// So that TEventWorker can call handleAsyncTaskComplete();
friend class TEventWorker;
/// Make the server a friend so it can manage tasks when overloaded
friend class TEventServer;
/// Make an async task a friend so it can communicate a cleanup() to us.
friend class TEventTask;
};
}}} // apache::thrift::async
#endif // #ifndef THRIFT_ASYNC_TEVENTCONNECTION_H_