usr.bin/csup/pathcomp.c

   1 /*-
   2  * Copyright (c) 2006, Maxime Henrion <mux@FreeBSD.org>
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  *
  26  * $FreeBSD$
  27  */
  28
  29 #include <assert.h>
  30 #include <stdlib.h>
  31 #include <string.h>
  32
  33 #include "misc.h"
  34 #include "pathcomp.h"
  35
  36 struct pathcomp {
  37         char *target;
  38         size_t targetlen;
  39         char *trashed;
  40         char *prev;
  41         size_t prevlen;
  42         size_t goal;
  43         size_t curlen;
  44 };
  45
  46 struct pathcomp *
  47 pathcomp_new(void)
  48 {
  49         struct pathcomp *pc;
  50
  51         pc = xmalloc(sizeof(struct pathcomp));
  52         pc->curlen = 0;
  53         pc->target = NULL;
  54         pc->targetlen = 0;
  55         pc->trashed = NULL;
  56         pc->prev = NULL;
  57         pc->prevlen = 0;
  58         return (pc);
  59 }
  60
  61 int
  62 pathcomp_put(struct pathcomp *pc, int type, char *path)
  63 {
  64         char *cp;
  65
  66         assert(pc->target == NULL);
  67         if (*path == '/')
  68                 return (-1);
  69
  70         switch (type) {
  71         case PC_DIRDOWN:
  72                 pc->target = path;
  73                 pc->targetlen = strlen(path);
  74                 break;
  75         case PC_FILE:
  76         case PC_DIRUP:
  77                 cp = strrchr(path, '/');
  78                 pc->target = path;
  79                 if (cp != NULL)
  80                         pc->targetlen = cp - path;
  81                 else
  82                         pc->targetlen = 0;
  83                 break;
  84         }
  85         if (pc->prev != NULL)
  86                 pc->goal = commonpathlength(pc->prev, pc->prevlen, pc->target,
  87                     pc->targetlen);
  88         else
  89                 pc->goal = 0;
  90         if (pc->curlen == pc->goal)     /* No need to go up. */
  91                 pc->goal = pc->targetlen;
  92         return (0);
  93 }
  94
  95 int
  96 pathcomp_get(struct pathcomp *pc, int *type, char **name)
  97 {
  98         char *cp;
  99         size_t slashpos, start;
 100
 101         if (pc->curlen > pc->goal) {            /* Going up. */
 102                 assert(pc->prev != NULL);
 103                 pc->prev[pc->curlen] = '\0';
 104                 cp = pc->prev + pc->curlen - 1;
 105                 while (cp >= pc->prev) {
 106                         if (*cp == '/')
 107                                 break;
 108                         cp--;
 109                 }
 110                 if (cp >= pc->prev)
 111                         slashpos = cp - pc->prev;
 112                 else
 113                         slashpos = 0;
 114                 pc->curlen = slashpos;
 115                 if (pc->curlen <= pc->goal) {   /* Done going up. */
 116                         assert(pc->curlen == pc->goal);
 117                         pc->goal = pc->targetlen;
 118                 }
 119                 *type = PC_DIRUP;
 120                 *name = pc->prev;
 121                 return (1);
 122         } else if (pc->curlen < pc->goal) {     /* Going down. */
 123                 /* Restore the previously overwritten '/' character. */
 124                 if (pc->trashed != NULL) {
 125                         *pc->trashed = '/';
 126                         pc->trashed = NULL;
 127                 }
 128                 if (pc->curlen == 0)
 129                         start = pc->curlen;
 130                 else
 131                         start = pc->curlen + 1;
 132                 slashpos = start;
 133                 while (slashpos < pc->goal) {
 134                         if (pc->target[slashpos] == '/')
 135                                 break;
 136                         slashpos++;
 137                 }
 138                 if (pc->target[slashpos] != '\0') {
 139                         assert(pc->target[slashpos] == '/');
 140                         pc->trashed = pc->target + slashpos;
 141                         pc->target[slashpos] = '\0';
 142                 }
 143                 pc->curlen = slashpos;
 144                 *type = PC_DIRDOWN;
 145                 *name = pc->target;
 146                 return (1);
 147         } else {        /* Done. */
 148                 if (pc->target != NULL) {
 149                         if (pc->trashed != NULL) {
 150                                 *pc->trashed = '/';
 151                                 pc->trashed = NULL;
 152                         }
 153                         if (pc->prev != NULL)
 154                                 free(pc->prev);
 155                         pc->prev = xmalloc(pc->targetlen + 1);
 156                         memcpy(pc->prev, pc->target, pc->targetlen);
 157                         pc->prev[pc->targetlen] = '\0';
 158                         pc->prevlen = pc->targetlen;
 159                         pc->target = NULL;
 160                         pc->targetlen = 0;
 161                 }
 162                 return (0);
 163         }
 164 }
 165
 166 void
 167 pathcomp_finish(struct pathcomp *pc)
 168 {
 169
 170         pc->target = NULL;
 171         pc->targetlen = 0;
 172         pc->goal = 0;
 173 }
 174
 175 void
 176 pathcomp_free(struct pathcomp *pc)
 177 {
 178
 179         if (pc->prev != NULL)
 180                 free(pc->prev);
 181         free(pc);
 182 }