MAJOR: connection: replace struct target with a pointer to an enum
Instead of storing a couple of (int, ptr) in the struct connection
and the struct session, we use a different method : we only store a
pointer to an integer which is stored inside the target object and
which contains a unique type identifier. That way, the pointer allows
us to retrieve the object type (by dereferencing it) and the object's
address (by computing the displacement in the target structure). The
NULL pointer always corresponds to OBJ_TYPE_NONE.
This reduces the size of the connection and session structs. It also
simplifies target assignment and compare.
In order to improve the generated code, we try to put the obj_type
element at the beginning of all the structs (listener, server, proxy,
si_applet), so that the original and target pointers are always equal.
A lot of code was touched by massive replaces, but the changes are not
that important.
diff --git a/include/types/obj_type.h b/include/types/obj_type.h
new file mode 100644
index 0000000..cfb3e34
--- /dev/null
+++ b/include/types/obj_type.h
@@ -0,0 +1,49 @@
+/*
+ * include/types/obj_type.h
+ * This file declares some object types for use in various structures.
+ *
+ * Copyright (C) 2000-2012 Willy Tarreau - w@1wt.eu
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation, version 2.1
+ * exclusively.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef _TYPES_OBJ_TYPE_H
+#define _TYPES_OBJ_TYPE_H
+
+/* The principle is to be able to change the type of a pointer by pointing
+ * it directly to an object type. The object type indicates the format of the
+ * structure holing the type, and this is used to retrieve the pointer to the
+ * beginning of the structure. Doing so saves us from having to maintain both
+ * a pointer and a type for elements such as connections which can point to
+ * various types of objects.
+ */
+
+/* object types */
+enum obj_type {
+ OBJ_TYPE_NONE = 0, /* pointer is NULL by definition */
+ OBJ_TYPE_LISTENER, /* object is a struct listener */
+ OBJ_TYPE_PROXY, /* object is a struct proxy */
+ OBJ_TYPE_SERVER, /* object is a struct server */
+ OBJ_TYPE_APPLET, /* object is a struct si_applet */
+};
+
+#endif /* _TYPES_OBJ_TYPE_H */
+
+/*
+ * Local variables:
+ * c-indent-level: 8
+ * c-basic-offset: 8
+ * End:
+ */