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/* pool.c: PROTOCOL IMPLEMENTATION
*
* $Id$
* Copyright (c) 2001 Ravenbrook Limited. See end of file for license.
*
* DESIGN
*
* .design: See <design/protocol/>
*/
#include "mpm.h"
SRCID(protocol, "$Id$");
/* ProtocolClassCheck -- check a protocol class */
Bool ProtocolClassCheck(ProtocolClass class)
{
CHECKS(ProtocolClass, class);
CHECKS(ProtocolClass, class->superclass);
CHECKL(FUNCHECK(class->coerceInst));
CHECKL(FUNCHECK(class->coerceClass));
return TRUE;
}
/* ProtocolInstCheck -- check a protocol instance */
Bool ProtocolInstCheck(ProtocolInst inst)
{
CHECKS(ProtocolInst, inst);
CHECKL(ProtocolClassCheck(inst->class));
return TRUE;
}
/* ProtocolIsSubclass -- a predicate for testing subclass relationships
*
* A protocol class is always a subclass of itself. This is implemented
* via the coerceClass method provided by each class.
*/
Bool ProtocolIsSubclass(ProtocolClass sub, ProtocolClass super)
{
ProtocolClass coerced;
AVERT(ProtocolClass, sub);
AVERT(ProtocolClass, super);
if (sub->coerceClass(&coerced, sub, super)) {
AVERT(ProtocolClass, coerced);
return TRUE;
} else {
return FALSE;
}
}
/* ProtocolCoerceClass -- the default method for coerceClass
*
* This default method must be inherited by any subclass
* which does not perform a multiple inheritance.
*/
static Bool ProtocolCoerceClass(ProtocolClass *coerceResult,
ProtocolClass proClass,
ProtocolClass super)
{
ProtocolClass p = proClass;
ProtocolClass root = ProtocolClassGet();
AVERT(ProtocolClass, proClass);
AVERT(ProtocolClass, super);
AVERT(ProtocolClass, root);
while (p != super) {
AVERT(ProtocolClass, p);
if (p == root)
return FALSE;
p = p->superclass;
}
*coerceResult = proClass;
return TRUE;
}
/* ProtocolCoerceInst -- the default method for coerceInst
*
* This default method must be inherited by any subclass
* which does not perform a multiple inheritance.
*/
static Bool ProtocolCoerceInst(ProtocolInst *coerceResult,
ProtocolInst proInst,
ProtocolClass super)
{
ProtocolClass p = proInst->class;
ProtocolClass root = ProtocolClassGet();
AVERT(ProtocolInst, proInst);
AVERT(ProtocolClass, super);
AVERT(ProtocolClass, root);
while (p != super) {
AVERT(ProtocolClass, p);
if (p == root)
return FALSE;
p = p->superclass;
}
*coerceResult = proInst;
return TRUE;
}
/* The class definition for the root of the hierarchy */
DEFINE_CLASS(ProtocolClass, theClass)
{
theClass->sig = ProtocolClassSig;
theClass->superclass = theClass;
theClass->coerceInst = ProtocolCoerceInst;
theClass->coerceClass = ProtocolCoerceClass;
}
/* C. COPYRIGHT AND LICENSE
*
* Copyright (C) 2001-2002 Ravenbrook Limited <http://www.ravenbrook.com/>.
* All rights reserved. This is an open source license. Contact
* Ravenbrook for commercial licensing options.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. 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.
*
* 3. Redistributions in any form must be accompanied by information on how
* to obtain complete source code for this software and any accompanying
* software that uses this software. The source code must either be
* included in the distribution or be available for no more than the cost
* of distribution plus a nominal fee, and must be freely redistributable
* under reasonable conditions. For an executable file, complete source
* code means the source code for all modules it contains. It does not
* include source code for modules or files that typically accompany the
* major components of the operating system on which the executable file
* runs.
*
* 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, FITNESS FOR A PARTICULAR
* PURPOSE, OR NON-INFRINGEMENT, ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT HOLDERS AND 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.
*/
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