merge2.c

   1 /*
   2  * wiggle - apply rejected patches
   3  *
   4  * Copyright (C) 2005 Neil Brown <neilb@cse.unsw.edu.au>
   5  * Copyright (C) 2010 Neil Brown <neilb@suse.de>
   6  *
   7  *
   8  *    This program is free software; you can redistribute it and/or modify
   9  *    it under the terms of the GNU General Public License as published by
  10  *    the Free Software Foundation; either version 2 of the License, or
  11  *    (at your option) any later version.
  12  *
  13  *    This program is distributed in the hope that it will be useful,
  14  *    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  *    GNU General Public License for more details.
  17  *
  18  *    You should have received a copy of the GNU General Public License
  19  *    along with this program; if not, write to the Free Software Foundation, Inc.,
  20  *    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  21  *
  22  *    Author: Neil Brown
  23  *    Email: <neilb@suse.de>
  24  */
  25
  26 #include "wiggle.h"
  27 #include <stdlib.h>
  28
  29 /*
  30  * Second attempt at merging....
  31  *
  32  * We want to create a mergelist which identifies 'orig' and 'after'
  33  * sections (from a and c) and conflicts (which are ranges of a,b,c which
  34  * all don't match).
  35  * It is also helpful to differentiate 'orig' sections that aren't
  36  * matched in 'b' with orig sections that are.
  37  * To help with highlighting, it will be useful to know where
  38  * the conflicts match the csl lists.
  39  *
  40  * This can all be achieved with a list of (a,b,c,c1,c1) 5-tuples.
  41  * If two consecutive differ in more than one of a,b,c, it is a
  42  * conflict.
  43  * If only 'a' differ, it is un-matched original.
  44  * If only 'b' differ, it is matched, unchanged original
  45  * If only 'c' differ, it is 1
  46  */
  47
  48 static inline int min(int a, int b)
  49 {
  50         return a < b ? a : b;
  51 }
  52 static inline void assert(int a)
  53 {
  54         if (!a)
  55                 abort();
  56 }
  57
  58 static int check_alreadyapplied(struct file af, struct file cf,
  59                                 struct merge *m)
  60 {
  61         int i;
  62         if (m->al != m->cl)
  63                 return 0;
  64         for (i = 0; i < m->al; i++) {
  65                 if (af.list[m->a+i].len != cf.list[m->c+i].len)
  66                         return 0;
  67                 if (strncmp(af.list[m->a+i].start,
  68                             cf.list[m->c+i].start,
  69                             af.list[m->a+i].len) != 0)
  70                         return 0;
  71         }
  72 #if 0
  73         printf("already applied %d,%d,%d - %d,%d,%d\n",
  74                m->a, m->b, m->c, m->al, m->bl, m->cl);
  75         printf(" %.10s - %.10s\n", af.list[m->a].start,
  76                cf.list[m->c].start);
  77 #endif
  78         m->type = AlreadyApplied;
  79         return 1;
  80 }
  81
  82 static int isolate_conflicts(struct file af, struct file bf, struct file cf,
  83                              struct csl *csl1, struct csl *csl2, int words,
  84                              struct merge *m)
  85 {
  86         /* A conflict indicates that something is definitely wrong
  87          * and so we need to be a bit suspicious of nearby apparent matches.
  88          * To display a conflict effectively we expands it's effect to
  89          * include any Extraneous, Unmatched, Changed or AlreadyApplied text.
  90          * Also, unless 'words', we need to include any partial lines
  91          * in the Unchanged text that forms the border of a conflict.
  92          *
  93          * A Changed text may also border a conflict, but it can
  94          * only border one conflict (where as an Unchanged can border
  95          * a preceeding and a following conflict).
  96          * The 'new' section of a Changed text appears in the
  97          * conflict as does any part of the original before
  98          * a newline.
  99          *
 100          */
 101         int i, j, k;
 102         int cnt = 0;
 103
 104         for (i = 0; m[i].type != End; i++)
 105                 if (m[i].type == Conflict) {
 106                         /* We have a conflict here.
 107                          * First search backwards for an Unchanged marking
 108                          * things as in_conflict.  Then find the
 109                          * cut-point in the Unchanged.  If there isn't one,
 110                          * keep looking.
 111                          *
 112                          * Then search forward doing the same thing.
 113                          */
 114                         cnt++;
 115                         m[i].in_conflict = 1;
 116                         j = i;
 117                         while (--j >= 0) {
 118                                 if (!m[j].in_conflict) {
 119                                         m[j].in_conflict = 1;
 120                                         m[j].lo = 0;
 121                                 } else if (m[j].type == Changed) {
 122                                         /* This can no longer form a border */
 123                                         m[j].hi = -1;
 124                                         /* We merge these conflicts and stop searching */
 125                                         cnt--;
 126                                         break;
 127                                 }
 128
 129                                 if (m[j].type == Unchanged || m[j].type == Changed) {
 130                                         if (words) {
 131                                                 m[j].hi = m[j].al;
 132                                                 break;
 133                                         }
 134                                         /* need to find the last line-break, which
 135                                          * might be after the last newline, if there
 136                                          * is one, or might be at the start
 137                                          */
 138                                         for (k = m[j].al; k > 0; k--)
 139                                                 if (ends_line(af.list[m[j].a+k-1]))
 140                                                         break;
 141                                         if (k > 0)
 142                                                 m[j].hi = k;
 143                                         else if ((m[j].a == 0 || ends_line(af.list[m[j].a-1])) &&
 144                                                  (m[j].b == 0 || ends_line(bf.list[m[j].b-1])) &&
 145                                                  (m[j].c == 0 || ends_line(cf.list[m[j].c-1])))
 146                                                 m[j].hi = 0;
 147                                         else
 148                                                 /* no start-of-line found... */
 149                                                 m[j].hi = -1;
 150                                         if (m[j].hi > 0 && m[j].type == Changed) {
 151                                                 /* this can only work if start is also a line break */
 152                                                 if ((m[j].a == 0 || ends_line(af.list[m[j].a-1])) &&
 153                                                     (m[j].b == 0 || ends_line(bf.list[m[j].b-1])) &&
 154                                                     (m[j].c == 0 || ends_line(cf.list[m[j].c-1])))
 155                                                         /* ok */;
 156                                                 else
 157                                                         m[j].hi = -1;
 158                                         }
 159                                         if (m[j].hi >= 0)
 160                                                 break;
 161                                 }
 162                         }
 163 #if 0
 164                         if (j >= 0 && m[j].in_conflict && m[j].type == Unchanged &&
 165                             m[j].hi == m[j].lo) {
 166                                 /* nothing to separate conflicts, merge them */
 167                                 m[j].lo = 0;
 168                                 m[j].hi = -1;
 169                                 cnt--;
 170                         }
 171 #endif
 172                         /* now the forward search */
 173                         for (j = i+1; m[j].type != End; j++) {
 174                                 m[j].in_conflict = 1;
 175                                 if (m[j].type == Unchanged || m[j].type == Changed) {
 176                                         m[j].hi = m[j].al;
 177                                         if (words) {
 178                                                 m[j].lo = 0;
 179                                                 break;
 180                                         }
 181                                         /* need to find a line-break, which might be at
 182                                          * the very beginning, or might be after the
 183                                          * first newline - if there is one
 184                                          */
 185                                         if ((m[j].a == 0 || ends_line(af.list[m[j].a-1])) &&
 186                                             (m[j].b == 0 || ends_line(bf.list[m[j].b-1])) &&
 187                                             (m[j].c == 0 || ends_line(cf.list[m[j].c-1])))
 188                                                 m[j].lo = 0;
 189                                         else {
 190                                                 for (k = 0 ; k < m[j].al ; k++)
 191                                                         if (ends_line(af.list[m[j].a+k]))
 192                                                                 break;
 193                                                 if (k < m[j].al)
 194                                                         m[j].lo = k+1;
 195                                                 else
 196                                                         /* no start-of-line found */
 197                                                         m[j].lo = m[j].al+1;
 198                                         }
 199                                         if (m[j].lo <= m[j].al+1 && m[j].type == Changed) {
 200                                                 /* this can only work if the end is a line break */
 201                                                 if (ends_line(af.list[m[j].a+m[j].al-1]) &&
 202                                                     ends_line(bf.list[m[j].b+m[j].bl-1]) &&
 203                                                     ends_line(cf.list[m[j].c+m[j].cl-1]))
 204                                                         /* ok */;
 205                                                 else
 206                                                         m[j].lo = m[j].al+1;
 207                                         }
 208                                         if (m[j].lo < m[j].al+1)
 209                                                 break;
 210                                 }
 211                         }
 212                         i = j - 1;
 213                 }
 214         return cnt;
 215 }
 216
 217 struct ci make_merger(struct file af, struct file bf, struct file cf,
 218                       struct csl *csl1, struct csl *csl2, int words,
 219                       int ignore_already)
 220 {
 221         /* find the wiggles and conflicts between csl1 and csl2
 222          */
 223         struct ci rv;
 224         int i, l;
 225         int a, b, c, c1, c2;
 226         int wiggle_found = 0;
 227
 228         rv.conflicts = rv.wiggles = rv.ignored = 0;
 229
 230         for (i = 0; csl1[i].len; i++)
 231                 ;
 232         l = i;
 233         for (i = 0; csl2[i].len; i++)
 234                 ;
 235         l += i;
 236         /* maybe a bit of slack at each end */
 237         l = l * 4 + 10;
 238
 239         rv.merger = xmalloc(sizeof(struct merge)*l);
 240
 241         a = b = c = c1 = c2 = 0;
 242         i = 0;
 243         while (1) {
 244                 int match1, match2;
 245                 match1 = (a >= csl1[c1].a && b >= csl1[c1].b); /* c1 doesn't match */
 246                 match2 = (b >= csl2[c2].a && c >= csl2[c2].b);
 247
 248                 rv.merger[i].a = a;
 249                 rv.merger[i].b = b;
 250                 rv.merger[i].c = c;
 251                 rv.merger[i].c1 = c1;
 252                 rv.merger[i].c2 = c2;
 253                 rv.merger[i].in_conflict = 0;
 254
 255                 if (!match1 && match2) {
 256                         if (a < csl1[c1].a) {
 257                                 /* some unmatched text */
 258                                 rv.merger[i].type = Unmatched;
 259                                 rv.merger[i].al = csl1[c1].a - a;
 260                                 rv.merger[i].bl = 0;
 261                                 rv.merger[i].cl = 0;
 262                                 wiggle_found++;
 263                         } else {
 264                                 int newb;
 265                                 int j;
 266                                 assert(b < csl1[c1].b);
 267                                 /* some Extraneous text */
 268                                 /* length is min of unmatched on left
 269                                  * and matched on right
 270                                  */
 271                                 rv.merger[i].type = Extraneous;
 272                                 rv.merger[i].al = 0;
 273                                 rv.merger[i].cl =
 274                                         rv.merger[i].bl =
 275                                         min(csl1[c1].b - b,
 276                                             csl2[c2].len - (b-csl2[c2].a));
 277                                 newb = b+rv.merger[i].bl;
 278                                 for (j = b; j < newb; j++) {
 279                                         if (bf.list[j].start[0] == '\0') {
 280                                                 if (wiggle_found > 1)
 281                                                         rv.wiggles++;
 282                                                 wiggle_found = 0;
 283                                         } else
 284                                                 wiggle_found++;
 285                                 }
 286                         }
 287                 } else if (match1 && !match2) {
 288                         /* some changed text
 289                          * if 'c' is currently at a suitable cut-point, then
 290                          * we can look for a triple-cut-point for start.
 291                          * Also, if csl2[c2].b isn't in a conflict, and is
 292                          * a suitable cut-point, then we could make a
 293                          * triple-cut-point for end of a conflict.
 294                          */
 295
 296                         rv.merger[i].type = Changed;
 297                         rv.merger[i].bl = min(csl1[c1].b+csl1[c1].len, csl2[c2].a) - b;
 298                         rv.merger[i].al = rv.merger[i].bl;
 299                         rv.merger[i].cl = csl2[c2].b - c;
 300                 } else if (match1 && match2) {
 301                         /* Some unchanged text
 302                          */
 303                         rv.merger[i].type = Unchanged;
 304                         rv.merger[i].bl =
 305                                 min(csl1[c1].len - (b-csl1[c1].b),
 306                                     csl2[c2].len - (b-csl2[c2].a));
 307                         rv.merger[i].al = rv.merger[i].cl =
 308                                 rv.merger[i].bl;
 309                 } else {
 310                         /* must be a conflict.
 311                          * Move a and c to next match, and b to closest of the two
 312                          */
 313                         rv.merger[i].type = Conflict;
 314                         rv.merger[i].al = csl1[c1].a - a;
 315                         rv.merger[i].cl = csl2[c2].b - c;
 316                         rv.merger[i].bl = min(csl1[c1].b, csl2[c2].a) - b;
 317                         if (ignore_already &&
 318                             check_alreadyapplied(af, cf, &rv.merger[i]))
 319                                 rv.ignored++;
 320                 }
 321                 a += rv.merger[i].al;
 322                 b += rv.merger[i].bl;
 323                 c += rv.merger[i].cl;
 324                 i++;
 325
 326                 while (csl1[c1].a + csl1[c1].len <= a && csl1[c1].len)
 327                         c1++;
 328                 assert(csl1[c1].b + csl1[c1].len >= b);
 329                 while (csl2[c2].b + csl2[c2].len <= c && csl2[c2].len)
 330                         c2++;
 331                 assert(csl2[c2].a + csl2[c2].len >= b);
 332                 if (csl1[c1].len == 0 && csl2[c2].len == 0 &&
 333                     a == csl1[c1].a && b == csl1[c1].b &&
 334                     b == csl2[c2].a && c == csl2[c2].b)
 335                         break;
 336         }
 337         rv.merger[i].type = End;
 338         rv.merger[i].in_conflict = 0;
 339         rv.conflicts = isolate_conflicts(af, bf, cf, csl1, csl2, words, rv.merger);
 340         if (wiggle_found)
 341                 rv.wiggles++;
 342         return rv;
 343 }
 344
 345 static void printrange(FILE *out, struct file *f, int start, int len)
 346 {
 347         while (len > 0) {
 348                 printword(out, f->list[start]);
 349                 start++;
 350                 len--;
 351         }
 352 }
 353
 354 struct ci print_merge2(FILE *out, struct file *a, struct file *b, struct file *c,
 355                        struct csl *c1, struct csl *c2,
 356                        int words, int ignore_already)
 357 {
 358         struct ci rv = make_merger(*a, *b, *c, c1, c2,
 359                                    words, ignore_already);
 360         struct merge *m;
 361
 362         for (m = rv.merger; m->type != End ; m++) {
 363                 struct merge *cm;
 364 #if 1
 365                 static int v = -1;
 366                 if (v == -1) {
 367                         if (getenv("WiggleVerbose"))
 368                                 v = 1;
 369                         else
 370                                 v = 0;
 371                 }
 372                 if (v)
 373                         printf("[%s: %d-%d,%d-%d,%d-%d%s(%d,%d)]\n",
 374                                m->type==Unmatched ? "Unmatched" :
 375                                m->type==Unchanged ? "Unchanged" :
 376                                m->type==Extraneous ? "Extraneous" :
 377                                m->type==Changed ? "Changed" :
 378                                m->type==AlreadyApplied ? "AlreadyApplied" :
 379                                m->type==Conflict ? "Conflict":"unknown",
 380                                m->a, m->a+m->al-1,
 381                                m->b, m->b+m->bl-1,
 382                                m->c, m->c+m->cl-1,
 383                                m->in_conflict ? " in_conflict" : "",
 384                                m->lo, m->hi);
 385 #endif
 386                 while (m->in_conflict) {
 387                         /* need to print from 'hi' to 'lo' of next
 388                          * Unchanged which is < it's hi
 389                          */
 390                         int st = 0, st1;
 391                         if (m->type == Unchanged || m->type == Changed)
 392                                 if (m->hi >= m->lo)
 393                                         st = m->hi;
 394                         st1 = st;
 395
 396                         if (m->type == Unchanged)
 397                                 printrange(out, a, m->a+m->lo, m->hi - m->lo);
 398
 399 #if 1
 400                 if (v)
 401                         for (cm = m; cm->in_conflict; cm++) {
 402                                 printf("{%s: %d-%d,%d-%d,%d-%d%s(%d,%d)}\n",
 403                                        cm->type==Unmatched?"Unmatched":
 404                                        cm->type==Unchanged?"Unchanged":
 405                                        cm->type==Extraneous?"Extraneous":
 406                                        cm->type==Changed?"Changed":
 407                                        cm->type==AlreadyApplied?"AlreadyApplied":
 408                                        cm->type==Conflict?"Conflict":"unknown",
 409                                        cm->a, cm->a+cm->al-1,
 410                                        cm->b, cm->b+cm->bl-1,
 411                                        cm->c, cm->c+cm->cl-1,
 412                                        cm->in_conflict ? " in_conflict" : "",
 413                                        cm->lo, cm->hi);
 414                                 if ((cm->type == Unchanged || cm->type == Changed) && cm != m && cm->lo < cm->hi)
 415                                         break;
 416                         }
 417 #endif
 418
 419                         fputs(words ? "<<<---" : "<<<<<<<\n", out);
 420                         for (cm = m; cm->in_conflict; cm++) {
 421                                 if ((cm->type == Unchanged || cm->type == Changed) && cm != m && cm->lo < cm->hi) {
 422                                         printrange(out, a, cm->a, cm->lo);
 423                                         break;
 424                                 }
 425                                 printrange(out, a, cm->a+st1, cm->al-st1);
 426                                 st1 = 0;
 427                         }
 428                         fputs(words ? "|||" : "|||||||\n", out);
 429                         st1 = st;
 430                         for (cm = m; cm->in_conflict; cm++) {
 431                                 if ((cm->type == Unchanged || cm->type == Changed) && cm != m && cm->lo < cm->hi) {
 432                                         printrange(out, b, cm->b, cm->lo);
 433                                         break;
 434                                 }
 435                                 printrange(out, b, cm->b+st1, cm->bl-st1);
 436                                 st1 = 0;
 437                         }
 438                         fputs(words ? "===" : "=======\n", out);
 439                         st1 = st;
 440                         for (cm = m; cm->in_conflict; cm++) {
 441                                 if (cm->type == Unchanged && cm != m && cm->lo < cm->hi) {
 442                                         printrange(out, c, cm->c, cm->lo);
 443                                         break;
 444                                 }
 445                                 if (cm->type == Changed)
 446                                         st1 = 0; /* All of result of change must be printed */
 447                                 printrange(out, c, cm->c+st1, cm->cl-st1);
 448                                 st1 = 0;
 449                         }
 450                         fputs(words ? "--->>>" : ">>>>>>>\n", out);
 451                         m = cm;
 452                         if (m->in_conflict && m->type == Unchanged
 453                             && m->hi >= m->al) {
 454                                 printrange(out, a, m->a+m->lo, m->hi-m->lo);
 455                                 m++;
 456                         }
 457                 }
 458
 459                 /* there is always some non-conflict after a conflict,
 460                  * unless we hit the end
 461                  */
 462                 if (m->type == End)
 463                         break;
 464 #if 1
 465                 if (v) {
 466                         printf("<<%s: %d-%d,%d-%d,%d-%d%s(%d,%d)>>\n",
 467                                m->type==Unmatched?"Unmatched":
 468                                m->type==Unchanged?"Unchanged":
 469                                m->type==Extraneous?"Extraneous":
 470                                m->type==Changed?"Changed":
 471                                m->type==AlreadyApplied?"AlreadyApplied":
 472                                m->type==Conflict?"Conflict":"unknown",
 473                                m->a, m->a+m->al-1,
 474                                m->b, m->b+m->bl-1,
 475                                m->c, m->c+m->cl-1,
 476                                m->in_conflict ? " in_conflict" : "",
 477                                m->lo, m->hi);
 478                 }
 479 #endif
 480                 switch (m->type) {
 481                 case Unchanged:
 482                 case AlreadyApplied:
 483                 case Unmatched:
 484                         printrange(out, a, m->a, m->al);
 485                         break;
 486                 case Extraneous:
 487                         break;
 488                 case Changed:
 489                         printrange(out, c, m->c, m->cl);
 490                         break;
 491                 case Conflict:
 492                 case End:
 493                         assert(0);
 494                 }
 495         }
 496         return rv;
 497 }