89 lines
3.2 KiB
C
89 lines
3.2 KiB
C
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/*
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* Copyright (c) 2019, Redis Labs
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* * Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* * Neither the name of Redis nor the names of its contributors may be used
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* to endorse or promote products derived from this software without
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* specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef __REDIS_CONNHELPERS_H
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#define __REDIS_CONNHELPERS_H
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#include "connection.h"
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/* These are helper functions that are common to different connection
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* implementations (currently sockets in connection.c and TLS in tls.c).
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*
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* Currently helpers implement the mechanisms for invoking connection
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* handlers and tracking connection references, to allow safe destruction
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* of connections from within a handler.
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*/
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/* Increment connection references.
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*
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* Inside a connection handler, we guarantee refs >= 1 so it is always
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* safe to connClose().
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*
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* In other cases where we don't want to prematurely lose the connection,
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* it can go beyond 1 as well; currently it is only done by connAccept().
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*/
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static inline void connIncrRefs(connection *conn) {
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conn->refs++;
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}
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/* Decrement connection references.
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*
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* Note that this is not intended to provide any automatic free logic!
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* callHandler() takes care of that for the common flows, and anywhere an
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* explicit connIncrRefs() is used, the caller is expected to take care of
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* that.
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*/
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static inline void connDecrRefs(connection *conn) {
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conn->refs--;
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}
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static inline int connHasRefs(connection *conn) {
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return conn->refs;
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}
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/* Helper for connection implementations to call handlers:
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* 1. Increment refs to protect the connection.
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* 2. Execute the handler (if set).
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* 3. Decrement refs and perform deferred close, if refs==0.
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*/
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static inline int callHandler(connection *conn, ConnectionCallbackFunc handler) {
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connIncrRefs(conn);
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if (handler) handler(conn);
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connDecrRefs(conn);
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if (conn->flags & CONN_FLAG_CLOSE_SCHEDULED) {
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if (!connHasRefs(conn)) connClose(conn);
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return 0;
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}
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return 1;
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}
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#endif /* __REDIS_CONNHELPERS_H */
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