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 #include <sys/types.h>
36
37 #include <err.h>
38 #include <fts.h>
39 #include <stdio.h>
40 #include <time.h>
41
42 #include "find.h"
43
44 static PLAN *yanknode(PLAN **);
45 static PLAN *yankexpr(PLAN **);
46
47 /*
48 * yanknode --
49 * destructively removes the top from the plan
50 */
51 static PLAN *
yanknode(PLAN ** planp)52 yanknode(PLAN **planp)
53 {
54 PLAN *node; /* top node removed from the plan */
55
56 if ((node = (*planp)) == NULL)
57 return (NULL);
58 (*planp) = (*planp)->next;
59 node->next = NULL;
60 return (node);
61 }
62
63 /*
64 * yankexpr --
65 * Removes one expression from the plan. This is used mainly by
66 * paren_squish. In comments below, an expression is either a
67 * simple node or a f_expr node containing a list of simple nodes.
68 */
69 static PLAN *
yankexpr(PLAN ** planp)70 yankexpr(PLAN **planp)
71 {
72 PLAN *next; /* temp node holding subexpression results */
73 PLAN *node; /* pointer to returned node or expression */
74 PLAN *tail; /* pointer to tail of subplan */
75 PLAN *subplan; /* pointer to head of ( ) expression */
76
77 /* first pull the top node from the plan */
78 if ((node = yanknode(planp)) == NULL)
79 return (NULL);
80
81 /*
82 * If the node is an '(' then we recursively slurp up expressions
83 * until we find its associated ')'. If it's a closing paren we
84 * just return it and unwind our recursion; all other nodes are
85 * complete expressions, so just return them.
86 */
87 if (node->execute == f_openparen)
88 for (tail = subplan = NULL;;) {
89 if ((next = yankexpr(planp)) == NULL)
90 errx(1, "(: missing closing ')'");
91 /*
92 * If we find a closing ')' we store the collected
93 * subplan in our '(' node and convert the node to
94 * a f_expr. The ')' we found is ignored. Otherwise,
95 * we just continue to add whatever we get to our
96 * subplan.
97 */
98 if (next->execute == f_closeparen) {
99 if (subplan == NULL)
100 errx(1, "(): empty inner expression");
101 node->p_data[0] = subplan;
102 node->execute = f_expr;
103 break;
104 } else {
105 if (subplan == NULL)
106 tail = subplan = next;
107 else {
108 tail->next = next;
109 tail = next;
110 }
111 tail->next = NULL;
112 }
113 }
114 return (node);
115 }
116
117 /*
118 * paren_squish --
119 * replaces "parenthesized" plans in our search plan with "expr" nodes.
120 */
121 PLAN *
paren_squish(PLAN * plan)122 paren_squish(PLAN *plan)
123 {
124 PLAN *expr; /* pointer to next expression */
125 PLAN *tail; /* pointer to tail of result plan */
126 PLAN *result; /* pointer to head of result plan */
127
128 result = tail = NULL;
129
130 /*
131 * the basic idea is to have yankexpr do all our work and just
132 * collect its results together.
133 */
134 while ((expr = yankexpr(&plan)) != NULL) {
135 /*
136 * if we find an unclaimed ')' it means there is a missing
137 * '(' someplace.
138 */
139 if (expr->execute == f_closeparen)
140 errx(1, "): no beginning '('");
141
142 /* add the expression to our result plan */
143 if (result == NULL)
144 tail = result = expr;
145 else {
146 tail->next = expr;
147 tail = expr;
148 }
149 tail->next = NULL;
150 }
151 return (result);
152 }
153
154 /*
155 * not_squish --
156 * compresses "!" expressions in our search plan.
157 */
158 PLAN *
not_squish(PLAN * plan)159 not_squish(PLAN *plan)
160 {
161 PLAN *next; /* next node being processed */
162 PLAN *node; /* temporary node used in f_not processing */
163 PLAN *tail; /* pointer to tail of result plan */
164 PLAN *result; /* pointer to head of result plan */
165
166 tail = result = NULL;
167
168 while ((next = yanknode(&plan))) {
169 /*
170 * if we encounter a ( expression ) then look for nots in
171 * the expr subplan.
172 */
173 if (next->execute == f_expr)
174 next->p_data[0] = not_squish(next->p_data[0]);
175
176 /*
177 * if we encounter a not, then snag the next node and place
178 * it in the not's subplan. As an optimization we compress
179 * several not's to zero or one not.
180 */
181 if (next->execute == f_not) {
182 int notlevel = 1;
183
184 node = yanknode(&plan);
185 while (node != NULL && node->execute == f_not) {
186 ++notlevel;
187 node = yanknode(&plan);
188 }
189 if (node == NULL)
190 errx(1, "!: no following expression");
191 if (node->execute == f_or)
192 errx(1, "!: nothing between ! and -o");
193 /*
194 * If we encounter ! ( expr ) then look for nots in
195 * the expr subplan.
196 */
197 if (node->execute == f_expr)
198 node->p_data[0] = not_squish(node->p_data[0]);
199 if (notlevel % 2 != 1)
200 next = node;
201 else
202 next->p_data[0] = node;
203 }
204
205 /* add the node to our result plan */
206 if (result == NULL)
207 tail = result = next;
208 else {
209 tail->next = next;
210 tail = next;
211 }
212 tail->next = NULL;
213 }
214 return (result);
215 }
216
217 /*
218 * or_squish --
219 * compresses -o expressions in our search plan.
220 */
221 PLAN *
or_squish(PLAN * plan)222 or_squish(PLAN *plan)
223 {
224 PLAN *next; /* next node being processed */
225 PLAN *tail; /* pointer to tail of result plan */
226 PLAN *result; /* pointer to head of result plan */
227
228 tail = result = next = NULL;
229
230 while ((next = yanknode(&plan)) != NULL) {
231 /*
232 * if we encounter a ( expression ) then look for or's in
233 * the expr subplan.
234 */
235 if (next->execute == f_expr)
236 next->p_data[0] = or_squish(next->p_data[0]);
237
238 /* if we encounter a not then look for or's in the subplan */
239 if (next->execute == f_not)
240 next->p_data[0] = or_squish(next->p_data[0]);
241
242 /*
243 * if we encounter an or, then place our collected plan in the
244 * or's first subplan and then recursively collect the
245 * remaining stuff into the second subplan and return the or.
246 */
247 if (next->execute == f_or) {
248 if (result == NULL)
249 errx(1, "-o: no expression before -o");
250 next->p_data[0] = result;
251 next->p_data[1] = or_squish(plan);
252 if (next->p_data[1] == NULL)
253 errx(1, "-o: no expression after -o");
254 return (next);
255 }
256
257 /* add the node to our result plan */
258 if (result == NULL)
259 tail = result = next;
260 else {
261 tail->next = next;
262 tail = next;
263 }
264 tail->next = NULL;
265 }
266 return (result);
267 }
268