1/***********************************************************************
2*                                                                      *
3*               This software is part of the ast package               *
4*          Copyright (c) 1985-2011 AT&T Intellectual Property          *
5*                      and is licensed under the                       *
6*                 Eclipse Public License, Version 1.0                  *
7*                    by AT&T Intellectual Property                     *
8*                                                                      *
9*                A copy of the License is available at                 *
10*          http://www.eclipse.org/org/documents/epl-v10.html           *
11*         (with md5 checksum b35adb5213ca9657e911e9befb180842)         *
12*                                                                      *
13*              Information and Software Systems Research               *
14*                            AT&T Research                             *
15*                           Florham Park NJ                            *
16*                                                                      *
17*                 Glenn Fowler <gsf@research.att.com>                  *
18*                  David Korn <dgk@research.att.com>                   *
19*                   Phong Vo <kpv@research.att.com>                    *
20*                                                                      *
21***********************************************************************/
22#include	"dthdr.h"
23
24/*	Change search method.
25**
26**	Written by Kiem-Phong Vo (05/25/96)
27*/
28
29#if __STD_C
30Dtmethod_t* dtmethod(Dt_t* dt, Dtmethod_t* meth)
31#else
32Dtmethod_t* dtmethod(dt, meth)
33Dt_t*		dt;
34Dtmethod_t*	meth;
35#endif
36{
37	Dtlink_t	*list;
38	Dtdisc_t	*disc = dt->disc;
39	Dtmethod_t	*oldmt = dt->meth;
40	Dtdata_t	*newdt, *olddt = dt->data;
41
42	if(!meth || meth == oldmt)
43		return oldmt;
44
45	/* ask discipline if switching to new method is ok */
46	if(disc->eventf && (*disc->eventf)(dt,DT_METH,(Void_t*)meth,disc) < 0)
47		return NIL(Dtmethod_t*);
48
49	list = dtextract(dt); /* extract elements out of dictionary */
50
51	/* try to create internal structure for new method */
52	if(dt->searchf == oldmt->searchf) /* ie, not viewpathing */
53		dt->searchf = meth->searchf;
54	dt->meth = meth;
55	dt->data = NIL(Dtdata_t*);
56	if((*dt->meth->eventf)(dt, DT_OPEN, NIL(Void_t*)) < 0 )
57		newdt = NIL(Dtdata_t*);
58	else	newdt = dt->data;
59
60	/* see what need to be done to data of the old method */
61	if(dt->searchf == meth->searchf)
62		dt->searchf = oldmt->searchf;
63	dt->meth = oldmt;
64	dt->data = olddt;
65	if(newdt) /* switch was successful, remove old data */
66	{	(void)(*dt->meth->eventf)(dt, DT_CLOSE, NIL(Void_t*));
67
68		if(dt->searchf == oldmt->searchf)
69			dt->searchf = meth->searchf;
70		dt->meth = meth;
71		dt->data = newdt;
72		dtrestore(dt, list);
73		return oldmt;
74	}
75	else /* switch failed, restore dictionary to previous states */
76	{	dtrestore(dt, list);
77		return NIL(Dtmethod_t*);
78	}
79}
80
81/* customize certain actions in a container data structure */
82int dtcustomize(Dt_t* dt, int type, int action)
83{
84	int	done = 0;
85
86	if((type&DT_SHARE) &&
87	   (!dt->meth->eventf || (*dt->meth->eventf)(dt, DT_SHARE, (Void_t*)((long)action)) >= 0) )
88	{	if(action <= 0 )
89			dt->data->type &= ~DT_SHARE;
90		else	dt->data->type |=  DT_SHARE;
91		done |= DT_SHARE;
92	}
93
94	if((type&DT_ANNOUNCE) &&
95	   (!dt->meth->eventf || (*dt->meth->eventf)(dt, DT_ANNOUNCE, (Void_t*)((long)action)) >= 0) )
96	{	if(action <= 0 )
97			dt->data->type &= ~DT_ANNOUNCE;
98		else	dt->data->type |=  DT_ANNOUNCE;
99		done |= DT_ANNOUNCE;
100	}
101
102	if((type&DT_OPTIMIZE) &&
103	   (!dt->meth->eventf || (*dt->meth->eventf)(dt, DT_OPTIMIZE, (Void_t*)((long)action)) >= 0) )
104		done |= DT_OPTIMIZE;
105
106	return done;
107}
108