Adding upstream version 5:7.2.4.upstream/5%7.2.4

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 88 insertions, 0 deletions

diff --git a/src/connhelpers.h b/src/connhelpers.h
new file mode 100644
index 0000000..b32e44d
--- /dev/null
+++ b/src/connhelpers.h
@@ -0,0 +1,88 @@
+
+/*
+ * 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.
+ */
+
+/* Increment 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 */