git/xdiff/xemit.c

   1 /*
   2  *  LibXDiff by Davide Libenzi ( File Differential Library )
   3  *  Copyright (C) 2003  Davide Libenzi
   4  *
   5  *  This library is free software; you can redistribute it and/or
   6  *  modify it under the terms of the GNU Lesser General Public
   7  *  License as published by the Free Software Foundation; either
   8  *  version 2.1 of the License, or (at your option) any later version.
   9  *
  10  *  This library is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  *  Lesser General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU Lesser General Public
  16  *  License along with this library; if not, write to the Free Software
  17  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18  *
  19  *  Davide Libenzi <davidel@xmailserver.org>
  20  *
  21  */
  22
  23 #include "xinclude.h"
  24
  25
  26
  27
  28 static long xdl_get_rec(xdfile_t *xdf, long ri, char const **rec);
  29 static int xdl_emit_record(xdfile_t *xdf, long ri, char const *pre, xdemitcb_t *ecb);
  30 static xdchange_t *xdl_get_hunk(xdchange_t *xscr, xdemitconf_t const *xecfg);
  31
  32
  33
  34
  35 static long xdl_get_rec(xdfile_t *xdf, long ri, char const **rec) {
  36
  37         *rec = xdf->recs[ri]->ptr;
  38
  39         return xdf->recs[ri]->size;
  40 }
  41
  42
  43 static int xdl_emit_record(xdfile_t *xdf, long ri, char const *pre, xdemitcb_t *ecb) {
  44         long size, psize = strlen(pre);
  45         char const *rec;
  46
  47         size = xdl_get_rec(xdf, ri, &rec);
  48         if (xdl_emit_diffrec(rec, size, pre, psize, ecb) < 0) {
  49
  50                 return -1;
  51         }
  52
  53         return 0;
  54 }
  55
  56
  57 /*
  58  * Starting at the passed change atom, find the latest change atom to be included
  59  * inside the differential hunk according to the specified configuration.
  60  */
  61 static xdchange_t *xdl_get_hunk(xdchange_t *xscr, xdemitconf_t const *xecfg) {
  62         xdchange_t *xch, *xchp;
  63
  64         for (xchp = xscr, xch = xscr->next; xch; xchp = xch, xch = xch->next)
  65                 if (xch->i1 - (xchp->i1 + xchp->chg1) > 2 * xecfg->ctxlen)
  66                         break;
  67
  68         return xchp;
  69 }
  70
  71
  72 static long def_ff(const char *rec, long len, char *buf, long sz, void *priv)
  73 {
  74         if (len > 0 &&
  75                         (isalpha((unsigned char)*rec) || /* identifier? */
  76                          *rec == '_' || /* also identifier? */
  77                          *rec == '$')) { /* identifiers from VMS and other esoterico */
  78                 if (len > sz)
  79                         len = sz;
  80                 while (0 < len && isspace((unsigned char)rec[len - 1]))
  81                         len--;
  82                 memcpy(buf, rec, len);
  83                 return len;
  84         }
  85         return -1;
  86 }
  87
  88 static void xdl_find_func(xdfile_t *xf, long i, char *buf, long sz, long *ll,
  89                 find_func_t ff, void *ff_priv) {
  90
  91         /*
  92          * Be quite stupid about this for now.  Find a line in the old file
  93          * before the start of the hunk (and context) which starts with a
  94          * plausible character.
  95          */
  96
  97         const char *rec;
  98         long len;
  99
 100         while (i-- > 0) {
 101                 len = xdl_get_rec(xf, i, &rec);
 102                 if ((*ll = ff(rec, len, buf, sz, ff_priv)) >= 0)
 103                         return;
 104         }
 105         *ll = 0;
 106 }
 107
 108
 109 static int xdl_emit_common(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
 110                            xdemitconf_t const *xecfg) {
 111         xdfile_t *xdf = &xe->xdf1;
 112         const char *rchg = xdf->rchg;
 113         long ix;
 114
 115         for (ix = 0; ix < xdf->nrec; ix++) {
 116                 if (rchg[ix])
 117                         continue;
 118                 if (xdl_emit_record(xdf, ix, "", ecb))
 119                         return -1;
 120         }
 121         return 0;
 122 }
 123
 124 int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
 125                   xdemitconf_t const *xecfg) {
 126         long s1, s2, e1, e2, lctx;
 127         xdchange_t *xch, *xche;
 128         char funcbuf[80];
 129         long funclen = 0;
 130         find_func_t ff = xecfg->find_func ?  xecfg->find_func : def_ff;
 131
 132         if (xecfg->flags & XDL_EMIT_COMMON)
 133                 return xdl_emit_common(xe, xscr, ecb, xecfg);
 134
 135         for (xch = xche = xscr; xch; xch = xche->next) {
 136                 xche = xdl_get_hunk(xch, xecfg);
 137
 138                 s1 = XDL_MAX(xch->i1 - xecfg->ctxlen, 0);
 139                 s2 = XDL_MAX(xch->i2 - xecfg->ctxlen, 0);
 140
 141                 lctx = xecfg->ctxlen;
 142                 lctx = XDL_MIN(lctx, xe->xdf1.nrec - (xche->i1 + xche->chg1));
 143                 lctx = XDL_MIN(lctx, xe->xdf2.nrec - (xche->i2 + xche->chg2));
 144
 145                 e1 = xche->i1 + xche->chg1 + lctx;
 146                 e2 = xche->i2 + xche->chg2 + lctx;
 147
 148                 /*
 149                  * Emit current hunk header.
 150                  */
 151
 152                 if (xecfg->flags & XDL_EMIT_FUNCNAMES) {
 153                         xdl_find_func(&xe->xdf1, s1, funcbuf,
 154                                       sizeof(funcbuf), &funclen,
 155                                       ff, xecfg->find_func_priv);
 156                 }
 157                 if (xdl_emit_hunk_hdr(s1 + 1, e1 - s1, s2 + 1, e2 - s2,
 158                                       funcbuf, funclen, ecb) < 0)
 159                         return -1;
 160
 161                 /*
 162                  * Emit pre-context.
 163                  */
 164                 for (; s1 < xch->i1; s1++)
 165                         if (xdl_emit_record(&xe->xdf1, s1, " ", ecb) < 0)
 166                                 return -1;
 167
 168                 for (s1 = xch->i1, s2 = xch->i2;; xch = xch->next) {
 169                         /*
 170                          * Merge previous with current change atom.
 171                          */
 172                         for (; s1 < xch->i1 && s2 < xch->i2; s1++, s2++)
 173                                 if (xdl_emit_record(&xe->xdf1, s1, " ", ecb) < 0)
 174                                         return -1;
 175
 176                         /*
 177                          * Removes lines from the first file.
 178                          */
 179                         for (s1 = xch->i1; s1 < xch->i1 + xch->chg1; s1++)
 180                                 if (xdl_emit_record(&xe->xdf1, s1, "-", ecb) < 0)
 181                                         return -1;
 182
 183                         /*
 184                          * Adds lines from the second file.
 185                          */
 186                         for (s2 = xch->i2; s2 < xch->i2 + xch->chg2; s2++)
 187                                 if (xdl_emit_record(&xe->xdf2, s2, "+", ecb) < 0)
 188                                         return -1;
 189
 190                         if (xch == xche)
 191                                 break;
 192                         s1 = xch->i1 + xch->chg1;
 193                         s2 = xch->i2 + xch->chg2;
 194                 }
 195
 196                 /*
 197                  * Emit post-context.
 198                  */
 199                 for (s1 = xche->i1 + xche->chg1; s1 < e1; s1++)
 200                         if (xdl_emit_record(&xe->xdf1, s1, " ", ecb) < 0)
 201                                 return -1;
 202         }
 203
 204         return 0;
 205 }