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/*
* Copyright (c) 2019, Redis Labs
* 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 Redis 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 __REDIS_CONNHELPERS_H
#define __REDIS_CONNHELPERS_H
#include "connection.h"
/* These are helper functions that are common to different connection
* implementations (currently sockets in connection.c and TLS in tls.c).
*
* Currently helpers implement the mechanisms for invoking connection
* handlers and tracking connection references, to allow safe destruction
* of connections from within a handler.
*/
/* Incremenet connection references.
*
* Inside a connection handler, we guarantee refs >= 1 so it is always
* safe to connClose().
*
* In other cases where we don't want to prematurely lose the connection,
* it can go beyond 1 as well; currently it is only done by connAccept().
*/
static inline void connIncrRefs(connection *conn) {
conn->refs++;
}
/* Decrement connection references.
*
* Note that this is not intended to provide any automatic free logic!
* callHandler() takes care of that for the common flows, and anywhere an
* explicit connIncrRefs() is used, the caller is expected to take care of
* that.
*/
static inline void connDecrRefs(connection *conn) {
conn->refs--;
}
static inline int connHasRefs(connection *conn) {
return conn->refs;
}
/* Helper for connection implementations to call handlers:
* 1. Increment refs to protect the connection.
* 2. Execute the handler (if set).
* 3. Decrement refs and perform deferred close, if refs==0.
*/
static inline int callHandler(connection *conn, ConnectionCallbackFunc handler) {
connIncrRefs(conn);
if (handler) handler(conn);
connDecrRefs(conn);
if (conn->flags & CONN_FLAG_CLOSE_SCHEDULED) {
if (!connHasRefs(conn)) connClose(conn);
return 0;
}
return 1;
}
#endif /* __REDIS_CONNHELPERS_H */
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