1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1990, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Cimarron D. Taylor of the University of California, Berkeley.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35 #if 0
36 static char sccsid[] = "@(#)operator.c 8.1 (Berkeley) 6/6/93";
37 #endif
38
39 #include <sys/cdefs.h>
40 __FBSDID("$FreeBSD$");
41
42 #include <sys/types.h>
43
44 #include <err.h>
45 #include <fts.h>
46 #include <stdio.h>
47 #include <time.h>
48
49 #include "find.h"
50
51 static PLAN *yanknode(PLAN **);
52 static PLAN *yankexpr(PLAN **);
53
54 /*
55 * yanknode --
56 * destructively removes the top from the plan
57 */
58 static PLAN *
yanknode(PLAN ** planp)59 yanknode(PLAN **planp)
60 {
61 PLAN *node; /* top node removed from the plan */
62
63 if ((node = (*planp)) == NULL)
64 return (NULL);
65 (*planp) = (*planp)->next;
66 node->next = NULL;
67 return (node);
68 }
69
70 /*
71 * yankexpr --
72 * Removes one expression from the plan. This is used mainly by
73 * paren_squish. In comments below, an expression is either a
74 * simple node or a f_expr node containing a list of simple nodes.
75 */
76 static PLAN *
yankexpr(PLAN ** planp)77 yankexpr(PLAN **planp)
78 {
79 PLAN *next; /* temp node holding subexpression results */
80 PLAN *node; /* pointer to returned node or expression */
81 PLAN *tail; /* pointer to tail of subplan */
82 PLAN *subplan; /* pointer to head of ( ) expression */
83
84 /* first pull the top node from the plan */
85 if ((node = yanknode(planp)) == NULL)
86 return (NULL);
87
88 /*
89 * If the node is an '(' then we recursively slurp up expressions
90 * until we find its associated ')'. If it's a closing paren we
91 * just return it and unwind our recursion; all other nodes are
92 * complete expressions, so just return them.
93 */
94 if (node->execute == f_openparen)
95 for (tail = subplan = NULL;;) {
96 if ((next = yankexpr(planp)) == NULL)
97 errx(1, "(: missing closing ')'");
98 /*
99 * If we find a closing ')' we store the collected
100 * subplan in our '(' node and convert the node to
101 * a f_expr. The ')' we found is ignored. Otherwise,
102 * we just continue to add whatever we get to our
103 * subplan.
104 */
105 if (next->execute == f_closeparen) {
106 if (subplan == NULL)
107 errx(1, "(): empty inner expression");
108 node->p_data[0] = subplan;
109 node->execute = f_expr;
110 break;
111 } else {
112 if (subplan == NULL)
113 tail = subplan = next;
114 else {
115 tail->next = next;
116 tail = next;
117 }
118 tail->next = NULL;
119 }
120 }
121 return (node);
122 }
123
124 /*
125 * paren_squish --
126 * replaces "parenthesized" plans in our search plan with "expr" nodes.
127 */
128 PLAN *
paren_squish(PLAN * plan)129 paren_squish(PLAN *plan)
130 {
131 PLAN *expr; /* pointer to next expression */
132 PLAN *tail; /* pointer to tail of result plan */
133 PLAN *result; /* pointer to head of result plan */
134
135 result = tail = NULL;
136
137 /*
138 * the basic idea is to have yankexpr do all our work and just
139 * collect its results together.
140 */
141 while ((expr = yankexpr(&plan)) != NULL) {
142 /*
143 * if we find an unclaimed ')' it means there is a missing
144 * '(' someplace.
145 */
146 if (expr->execute == f_closeparen)
147 errx(1, "): no beginning '('");
148
149 /* add the expression to our result plan */
150 if (result == NULL)
151 tail = result = expr;
152 else {
153 tail->next = expr;
154 tail = expr;
155 }
156 tail->next = NULL;
157 }
158 return (result);
159 }
160
161 /*
162 * not_squish --
163 * compresses "!" expressions in our search plan.
164 */
165 PLAN *
not_squish(PLAN * plan)166 not_squish(PLAN *plan)
167 {
168 PLAN *next; /* next node being processed */
169 PLAN *node; /* temporary node used in f_not processing */
170 PLAN *tail; /* pointer to tail of result plan */
171 PLAN *result; /* pointer to head of result plan */
172
173 tail = result = NULL;
174
175 while ((next = yanknode(&plan))) {
176 /*
177 * if we encounter a ( expression ) then look for nots in
178 * the expr subplan.
179 */
180 if (next->execute == f_expr)
181 next->p_data[0] = not_squish(next->p_data[0]);
182
183 /*
184 * if we encounter a not, then snag the next node and place
185 * it in the not's subplan. As an optimization we compress
186 * several not's to zero or one not.
187 */
188 if (next->execute == f_not) {
189 int notlevel = 1;
190
191 node = yanknode(&plan);
192 while (node != NULL && node->execute == f_not) {
193 ++notlevel;
194 node = yanknode(&plan);
195 }
196 if (node == NULL)
197 errx(1, "!: no following expression");
198 if (node->execute == f_or)
199 errx(1, "!: nothing between ! and -o");
200 /*
201 * If we encounter ! ( expr ) then look for nots in
202 * the expr subplan.
203 */
204 if (node->execute == f_expr)
205 node->p_data[0] = not_squish(node->p_data[0]);
206 if (notlevel % 2 != 1)
207 next = node;
208 else
209 next->p_data[0] = node;
210 }
211
212 /* add the node to our result plan */
213 if (result == NULL)
214 tail = result = next;
215 else {
216 tail->next = next;
217 tail = next;
218 }
219 tail->next = NULL;
220 }
221 return (result);
222 }
223
224 /*
225 * or_squish --
226 * compresses -o expressions in our search plan.
227 */
228 PLAN *
or_squish(PLAN * plan)229 or_squish(PLAN *plan)
230 {
231 PLAN *next; /* next node being processed */
232 PLAN *tail; /* pointer to tail of result plan */
233 PLAN *result; /* pointer to head of result plan */
234
235 tail = result = next = NULL;
236
237 while ((next = yanknode(&plan)) != NULL) {
238 /*
239 * if we encounter a ( expression ) then look for or's in
240 * the expr subplan.
241 */
242 if (next->execute == f_expr)
243 next->p_data[0] = or_squish(next->p_data[0]);
244
245 /* if we encounter a not then look for or's in the subplan */
246 if (next->execute == f_not)
247 next->p_data[0] = or_squish(next->p_data[0]);
248
249 /*
250 * if we encounter an or, then place our collected plan in the
251 * or's first subplan and then recursively collect the
252 * remaining stuff into the second subplan and return the or.
253 */
254 if (next->execute == f_or) {
255 if (result == NULL)
256 errx(1, "-o: no expression before -o");
257 next->p_data[0] = result;
258 next->p_data[1] = or_squish(plan);
259 if (next->p_data[1] == NULL)
260 errx(1, "-o: no expression after -o");
261 return (next);
262 }
263
264 /* add the node to our result plan */
265 if (result == NULL)
266 tail = result = next;
267 else {
268 tail->next = next;
269 tail = next;
270 }
271 tail->next = NULL;
272 }
273 return (result);
274 }
275