src/xdiff/xmerge.c

   1 /*
   2  *  LibXDiff by Davide Libenzi ( File Differential Library )
   3  *  Copyright (C) 2003-2006 Davide Libenzi, Johannes E. Schindelin
   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, see
  17  *  <http://www.gnu.org/licenses/>.
  18  *
  19  *  Davide Libenzi <davidel@xmailserver.org>
  20  *
  21  */
  22
  23 #include "xinclude.h"
  24
  25 typedef struct s_xdmerge {
  26         struct s_xdmerge *next;
  27         /*
  28          * 0 = conflict,
  29          * 1 = no conflict, take first,
  30          * 2 = no conflict, take second.
  31          * 3 = no conflict, take both.
  32          */
  33         int mode;
  34         /*
  35          * These point at the respective postimages.  E.g. <i1,chg1> is
  36          * how side #1 wants to change the common ancestor; if there is no
  37          * overlap, lines before i1 in the postimage of side #1 appear
  38          * in the merge result as a region touched by neither side.
  39          */
  40         long i1, i2;
  41         long chg1, chg2;
  42         /*
  43          * These point at the preimage; of course there is just one
  44          * preimage, that is from the shared common ancestor.
  45          */
  46         long i0;
  47         long chg0;
  48 } xdmerge_t;
  49
  50 static int xdl_append_merge(xdmerge_t **merge, int mode,
  51                             long i0, long chg0,
  52                             long i1, long chg1,
  53                             long i2, long chg2)
  54 {
  55         xdmerge_t *m = *merge;
  56         if (m && (i1 <= m->i1 + m->chg1 || i2 <= m->i2 + m->chg2)) {
  57                 if (mode != m->mode)
  58                         m->mode = 0;
  59                 m->chg0 = i0 + chg0 - m->i0;
  60                 m->chg1 = i1 + chg1 - m->i1;
  61                 m->chg2 = i2 + chg2 - m->i2;
  62         } else {
  63                 m = xdl_malloc(sizeof(xdmerge_t));
  64                 if (!m)
  65                         return -1;
  66                 m->next = NULL;
  67                 m->mode = mode;
  68                 m->i0 = i0;
  69                 m->chg0 = chg0;
  70                 m->i1 = i1;
  71                 m->chg1 = chg1;
  72                 m->i2 = i2;
  73                 m->chg2 = chg2;
  74                 if (*merge)
  75                         (*merge)->next = m;
  76                 *merge = m;
  77         }
  78         return 0;
  79 }
  80
  81 static int xdl_cleanup_merge(xdmerge_t *c)
  82 {
  83         int count = 0;
  84         xdmerge_t *next_c;
  85
  86         /* were there conflicts? */
  87         for (; c; c = next_c) {
  88                 if (c->mode == 0)
  89                         count++;
  90                 next_c = c->next;
  91                 free(c);
  92         }
  93         return count;
  94 }
  95
  96 static int xdl_merge_cmp_lines(xdfenv_t *xe1, int i1, xdfenv_t *xe2, int i2,
  97                 int line_count, long flags)
  98 {
  99         int i;
 100         xrecord_t **rec1 = xe1->xdf2.recs + i1;
 101         xrecord_t **rec2 = xe2->xdf2.recs + i2;
 102
 103         for (i = 0; i < line_count; i++) {
 104                 int result = xdl_recmatch(rec1[i]->ptr, rec1[i]->size,
 105                         rec2[i]->ptr, rec2[i]->size, flags);
 106                 if (!result)
 107                         return -1;
 108         }
 109         return 0;
 110 }
 111
 112 static int xdl_recs_copy_0(size_t *out, int use_orig, xdfenv_t *xe, int i, int count, int needs_cr, int add_nl, char *dest)
 113 {
 114         xrecord_t **recs;
 115         size_t size = 0;
 116
 117         *out = 0;
 118
 119         recs = (use_orig ? xe->xdf1.recs : xe->xdf2.recs) + i;
 120
 121         if (count < 1)
 122                 return 0;
 123
 124         for (i = 0; i < count; ) {
 125                 if (dest)
 126                         memcpy(dest + size, recs[i]->ptr, recs[i]->size);
 127
 128                 GITERR_CHECK_ALLOC_ADD(&size, size, recs[i++]->size);
 129         }
 130
 131         if (add_nl) {
 132                 i = recs[count - 1]->size;
 133                 if (i == 0 || recs[count - 1]->ptr[i - 1] != '\n') {
 134                         if (needs_cr) {
 135                                 if (dest)
 136                                         dest[size] = '\r';
 137                                 GITERR_CHECK_ALLOC_ADD(&size, size, 1);
 138                         }
 139
 140                         if (dest)
 141                                 dest[size] = '\n';
 142
 143                         GITERR_CHECK_ALLOC_ADD(&size, size, 1);
 144                 }
 145         }
 146
 147         *out = size;
 148         return 0;
 149 }
 150
 151 static int xdl_recs_copy(size_t *out, xdfenv_t *xe, int i, int count, int needs_cr, int add_nl, char *dest)
 152 {
 153         return xdl_recs_copy_0(out, 0, xe, i, count, needs_cr, add_nl, dest);
 154 }
 155
 156 static int xdl_orig_copy(size_t *out, xdfenv_t *xe, int i, int count, int needs_cr, int add_nl, char *dest)
 157 {
 158         return xdl_recs_copy_0(out, 1, xe, i, count, needs_cr, add_nl, dest);
 159 }
 160
 161 /*
 162  * Returns 1 if the i'th line ends in CR/LF (if it is the last line and
 163  * has no eol, the preceding line, if any), 0 if it ends in LF-only, and
 164  * -1 if the line ending cannot be determined.
 165  */
 166 static int is_eol_crlf(xdfile_t *file, int i)
 167 {
 168         long size;
 169
 170         if (i < file->nrec - 1)
 171                 /* All lines before the last *must* end in LF */
 172                 return (size = file->recs[i]->size) > 1 &&
 173                         file->recs[i]->ptr[size - 2] == '\r';
 174         if (!file->nrec)
 175                 /* Cannot determine eol style from empty file */
 176                 return -1;
 177         if ((size = file->recs[i]->size) &&
 178                         file->recs[i]->ptr[size - 1] == '\n')
 179                 /* Last line; ends in LF; Is it CR/LF? */
 180                 return size > 1 &&
 181                         file->recs[i]->ptr[size - 2] == '\r';
 182         if (!i)
 183                 /* The only line has no eol */
 184                 return -1;
 185         /* Determine eol from second-to-last line */
 186         return (size = file->recs[i - 1]->size) > 1 &&
 187                 file->recs[i - 1]->ptr[size - 2] == '\r';
 188 }
 189
 190 static int is_cr_needed(xdfenv_t *xe1, xdfenv_t *xe2, xdmerge_t *m)
 191 {
 192         int needs_cr;
 193
 194         /* Match post-images' preceding, or first, lines' end-of-line style */
 195         needs_cr = is_eol_crlf(&xe1->xdf2, m->i1 ? m->i1 - 1 : 0);
 196         if (needs_cr)
 197                 needs_cr = is_eol_crlf(&xe2->xdf2, m->i2 ? m->i2 - 1 : 0);
 198         /* Look at pre-image's first line, unless we already settled on LF */
 199         if (needs_cr)
 200                 needs_cr = is_eol_crlf(&xe1->xdf1, 0);
 201         /* If still undecided, use LF-only */
 202         return needs_cr < 0 ? 0 : needs_cr;
 203 }
 204
 205 static int fill_conflict_hunk(size_t *out, xdfenv_t *xe1, const char *name1,
 206                               xdfenv_t *xe2, const char *name2,
 207                               const char *name3,
 208                               size_t size, int i, int style,
 209                               xdmerge_t *m, char *dest, int marker_size)
 210 {
 211         int marker1_size = (name1 ? (int)strlen(name1) + 1 : 0);
 212         int marker2_size = (name2 ? (int)strlen(name2) + 1 : 0);
 213         int marker3_size = (name3 ? (int)strlen(name3) + 1 : 0);
 214         int needs_cr = is_cr_needed(xe1, xe2, m);
 215         size_t copied;
 216
 217         *out = 0;
 218
 219         if (marker_size <= 0)
 220                 marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
 221
 222         /* Before conflicting part */
 223         if (xdl_recs_copy(&copied, xe1, i, m->i1 - i, 0, 0,
 224                               dest ? dest + size : NULL) < 0)
 225                 return -1;
 226
 227         GITERR_CHECK_ALLOC_ADD(&size, size, copied);
 228
 229         if (!dest) {
 230                 GITERR_CHECK_ALLOC_ADD5(&size, size, marker_size, 1, needs_cr,  marker1_size);
 231         } else {
 232                 memset(dest + size, '<', marker_size);
 233                 size += marker_size;
 234                 if (marker1_size) {
 235                         dest[size] = ' ';
 236                         memcpy(dest + size + 1, name1, marker1_size - 1);
 237                         size += marker1_size;
 238                 }
 239                 if (needs_cr)
 240                         dest[size++] = '\r';
 241                 dest[size++] = '\n';
 242         }
 243
 244         /* Postimage from side #1 */
 245         if (xdl_recs_copy(&copied, xe1, m->i1, m->chg1, needs_cr, 1,
 246                               dest ? dest + size : NULL) < 0)
 247                 return -1;
 248
 249         GITERR_CHECK_ALLOC_ADD(&size, size, copied);
 250
 251         if (style == XDL_MERGE_DIFF3) {
 252                 /* Shared preimage */
 253                 if (!dest) {
 254                         GITERR_CHECK_ALLOC_ADD5(&size, size, marker_size, 1, needs_cr, marker3_size);
 255                 } else {
 256                         memset(dest + size, '|', marker_size);
 257                         size += marker_size;
 258                         if (marker3_size) {
 259                                 dest[size] = ' ';
 260                                 memcpy(dest + size + 1, name3, marker3_size - 1);
 261                                 size += marker3_size;
 262                         }
 263                         if (needs_cr)
 264                                 dest[size++] = '\r';
 265                         dest[size++] = '\n';
 266                 }
 267
 268                 if (xdl_orig_copy(&copied, xe1, m->i0, m->chg0, needs_cr, 1,
 269                                       dest ? dest + size : NULL) < 0)
 270                         return -1;
 271                 GITERR_CHECK_ALLOC_ADD(&size, size, copied);
 272         }
 273
 274         if (!dest) {
 275                 GITERR_CHECK_ALLOC_ADD4(&size, size, marker_size, 1, needs_cr);
 276         } else {
 277                 memset(dest + size, '=', marker_size);
 278                 size += marker_size;
 279                 if (needs_cr)
 280                         dest[size++] = '\r';
 281                 dest[size++] = '\n';
 282         }
 283
 284         /* Postimage from side #2 */
 285
 286         if (xdl_recs_copy(&copied, xe2, m->i2, m->chg2, needs_cr, 1,
 287                               dest ? dest + size : NULL) < 0)
 288                 return -1;
 289         GITERR_CHECK_ALLOC_ADD(&size, size, copied);
 290
 291         if (!dest) {
 292                 GITERR_CHECK_ALLOC_ADD5(&size, size, marker_size, 1, needs_cr, marker2_size);
 293         } else {
 294                 memset(dest + size, '>', marker_size);
 295                 size += marker_size;
 296                 if (marker2_size) {
 297                         dest[size] = ' ';
 298                         memcpy(dest + size + 1, name2, marker2_size - 1);
 299                         size += marker2_size;
 300                 }
 301                 if (needs_cr)
 302                         dest[size++] = '\r';
 303                 dest[size++] = '\n';
 304         }
 305
 306         *out = size;
 307         return 0;
 308 }
 309
 310 static int xdl_fill_merge_buffer(size_t *out,
 311                                  xdfenv_t *xe1, const char *name1,
 312                                  xdfenv_t *xe2, const char *name2,
 313                                  const char *ancestor_name,
 314                                  int favor,
 315                                  xdmerge_t *m, char *dest, int style,
 316                                  int marker_size)
 317 {
 318         size_t size, copied;
 319         int i;
 320
 321         *out = 0;
 322
 323         for (size = i = 0; m; m = m->next) {
 324                 if (favor && !m->mode)
 325                         m->mode = favor;
 326
 327                 if (m->mode == 0) {
 328                         if (fill_conflict_hunk(&size, xe1, name1, xe2, name2,
 329                                                   ancestor_name,
 330                                                   size, i, style, m, dest,
 331                                                   marker_size) < 0)
 332                                 return -1;
 333                 }
 334                 else if (m->mode & 3) {
 335                         /* Before conflicting part */
 336                         if (xdl_recs_copy(&copied, xe1, i, m->i1 - i, 0, 0,
 337                                               dest ? dest + size : NULL) < 0)
 338                                 return -1;
 339                         GITERR_CHECK_ALLOC_ADD(&size, size, copied);
 340
 341                         /* Postimage from side #1 */
 342                         if (m->mode & 1) {
 343                                 int needs_cr = is_cr_needed(xe1, xe2, m);
 344
 345                                 if (xdl_recs_copy(&copied, xe1, m->i1, m->chg1, needs_cr, (m->mode & 2),
 346                                                       dest ? dest + size : NULL) < 0)
 347                                         return -1;
 348                                 GITERR_CHECK_ALLOC_ADD(&size, size, copied);
 349                         }
 350
 351                         /* Postimage from side #2 */
 352                         if (m->mode & 2) {
 353                                 if (xdl_recs_copy(&copied, xe2, m->i2, m->chg2, 0, 0,
 354                                                       dest ? dest + size : NULL) < 0)
 355                                         return -1;
 356                                 GITERR_CHECK_ALLOC_ADD(&size, size, copied);
 357                         }
 358                 } else
 359                         continue;
 360                 i = m->i1 + m->chg1;
 361         }
 362
 363         if (xdl_recs_copy(&copied, xe1, i, xe1->xdf2.nrec - i, 0, 0,
 364                               dest ? dest + size : NULL) < 0)
 365                 return -1;
 366         GITERR_CHECK_ALLOC_ADD(&size, size, copied);
 367
 368         *out = size;
 369         return 0;
 370 }
 371
 372 /*
 373  * Sometimes, changes are not quite identical, but differ in only a few
 374  * lines. Try hard to show only these few lines as conflicting.
 375  */
 376 static int xdl_refine_conflicts(xdfenv_t *xe1, xdfenv_t *xe2, xdmerge_t *m,
 377                 xpparam_t const *xpp)
 378 {
 379         for (; m; m = m->next) {
 380                 mmfile_t t1, t2;
 381                 xdfenv_t xe;
 382                 xdchange_t *xscr, *x;
 383                 int i1 = m->i1, i2 = m->i2;
 384
 385                 /* let's handle just the conflicts */
 386                 if (m->mode)
 387                         continue;
 388
 389                 /* no sense refining a conflict when one side is empty */
 390                 if (m->chg1 == 0 || m->chg2 == 0)
 391                         continue;
 392
 393                 /*
 394                  * This probably does not work outside git, since
 395                  * we have a very simple mmfile structure.
 396                  */
 397                 t1.ptr = (char *)xe1->xdf2.recs[m->i1]->ptr;
 398                 t1.size = xe1->xdf2.recs[m->i1 + m->chg1 - 1]->ptr
 399                         + xe1->xdf2.recs[m->i1 + m->chg1 - 1]->size - t1.ptr;
 400                 t2.ptr = (char *)xe2->xdf2.recs[m->i2]->ptr;
 401                 t2.size = xe2->xdf2.recs[m->i2 + m->chg2 - 1]->ptr
 402                         + xe2->xdf2.recs[m->i2 + m->chg2 - 1]->size - t2.ptr;
 403                 if (xdl_do_diff(&t1, &t2, xpp, &xe) < 0)
 404                         return -1;
 405                 if (xdl_change_compact(&xe.xdf1, &xe.xdf2, xpp->flags) < 0 ||
 406                     xdl_change_compact(&xe.xdf2, &xe.xdf1, xpp->flags) < 0 ||
 407                     xdl_build_script(&xe, &xscr) < 0) {
 408                         xdl_free_env(&xe);
 409                         return -1;
 410                 }
 411                 if (!xscr) {
 412                         /* If this happens, the changes are identical. */
 413                         xdl_free_env(&xe);
 414                         m->mode = 4;
 415                         continue;
 416                 }
 417                 x = xscr;
 418                 m->i1 = xscr->i1 + i1;
 419                 m->chg1 = xscr->chg1;
 420                 m->i2 = xscr->i2 + i2;
 421                 m->chg2 = xscr->chg2;
 422                 while (xscr->next) {
 423                         xdmerge_t *m2 = xdl_malloc(sizeof(xdmerge_t));
 424                         if (!m2) {
 425                                 xdl_free_env(&xe);
 426                                 xdl_free_script(x);
 427                                 return -1;
 428                         }
 429                         xscr = xscr->next;
 430                         m2->next = m->next;
 431                         m->next = m2;
 432                         m = m2;
 433                         m->mode = 0;
 434                         m->i1 = xscr->i1 + i1;
 435                         m->chg1 = xscr->chg1;
 436                         m->i2 = xscr->i2 + i2;
 437                         m->chg2 = xscr->chg2;
 438                 }
 439                 xdl_free_env(&xe);
 440                 xdl_free_script(x);
 441         }
 442         return 0;
 443 }
 444
 445 static int line_contains_alnum(const char *ptr, long size)
 446 {
 447         while (size--)
 448                 if (isalnum((unsigned char)*(ptr++)))
 449                         return 1;
 450         return 0;
 451 }
 452
 453 static int lines_contain_alnum(xdfenv_t *xe, int i, int chg)
 454 {
 455         for (; chg; chg--, i++)
 456                 if (line_contains_alnum(xe->xdf2.recs[i]->ptr,
 457                                 xe->xdf2.recs[i]->size))
 458                         return 1;
 459         return 0;
 460 }
 461
 462 /*
 463  * This function merges m and m->next, marking everything between those hunks
 464  * as conflicting, too.
 465  */
 466 static void xdl_merge_two_conflicts(xdmerge_t *m)
 467 {
 468         xdmerge_t *next_m = m->next;
 469         m->chg1 = next_m->i1 + next_m->chg1 - m->i1;
 470         m->chg2 = next_m->i2 + next_m->chg2 - m->i2;
 471         m->next = next_m->next;
 472         free(next_m);
 473 }
 474
 475 /*
 476  * If there are less than 3 non-conflicting lines between conflicts,
 477  * it appears simpler -- because it takes up less (or as many) lines --
 478  * if the lines are moved into the conflicts.
 479  */
 480 static int xdl_simplify_non_conflicts(xdfenv_t *xe1, xdmerge_t *m,
 481                                       int simplify_if_no_alnum)
 482 {
 483         int result = 0;
 484
 485         if (!m)
 486                 return result;
 487         for (;;) {
 488                 xdmerge_t *next_m = m->next;
 489                 int begin, end;
 490
 491                 if (!next_m)
 492                         return result;
 493
 494                 begin = m->i1 + m->chg1;
 495                 end = next_m->i1;
 496
 497                 if (m->mode != 0 || next_m->mode != 0 ||
 498                     (end - begin > 3 &&
 499                      (!simplify_if_no_alnum ||
 500                       lines_contain_alnum(xe1, begin, end - begin)))) {
 501                         m = next_m;
 502                 } else {
 503                         result++;
 504                         xdl_merge_two_conflicts(m);
 505                 }
 506         }
 507 }
 508
 509 /*
 510  * level == 0: mark all overlapping changes as conflict
 511  * level == 1: mark overlapping changes as conflict only if not identical
 512  * level == 2: analyze non-identical changes for minimal conflict set
 513  * level == 3: analyze non-identical changes for minimal conflict set, but
 514  *             treat hunks not containing any letter or number as conflicting
 515  *
 516  * returns < 0 on error, == 0 for no conflicts, else number of conflicts
 517  */
 518 static int xdl_do_merge(xdfenv_t *xe1, xdchange_t *xscr1,
 519                 xdfenv_t *xe2, xdchange_t *xscr2,
 520                 xmparam_t const *xmp, mmbuffer_t *result)
 521 {
 522         xdmerge_t *changes, *c;
 523         xpparam_t const *xpp = &xmp->xpp;
 524         const char *const ancestor_name = xmp->ancestor;
 525         const char *const name1 = xmp->file1;
 526         const char *const name2 = xmp->file2;
 527         int i0, i1, i2, chg0, chg1, chg2;
 528         int level = xmp->level;
 529         int style = xmp->style;
 530         int favor = xmp->favor;
 531
 532         if (style == XDL_MERGE_DIFF3) {
 533                 /*
 534                  * "diff3 -m" output does not make sense for anything
 535                  * more aggressive than XDL_MERGE_EAGER.
 536                  */
 537                 if (XDL_MERGE_EAGER < level)
 538                         level = XDL_MERGE_EAGER;
 539         }
 540
 541         c = changes = NULL;
 542
 543         while (xscr1 && xscr2) {
 544                 if (!changes)
 545                         changes = c;
 546                 if (xscr1->i1 + xscr1->chg1 < xscr2->i1) {
 547                         i0 = xscr1->i1;
 548                         i1 = xscr1->i2;
 549                         i2 = xscr2->i2 - xscr2->i1 + xscr1->i1;
 550                         chg0 = xscr1->chg1;
 551                         chg1 = xscr1->chg2;
 552                         chg2 = xscr1->chg1;
 553                         if (xdl_append_merge(&c, 1,
 554                                              i0, chg0, i1, chg1, i2, chg2)) {
 555                                 xdl_cleanup_merge(changes);
 556                                 return -1;
 557                         }
 558                         xscr1 = xscr1->next;
 559                         continue;
 560                 }
 561                 if (xscr2->i1 + xscr2->chg1 < xscr1->i1) {
 562                         i0 = xscr2->i1;
 563                         i1 = xscr1->i2 - xscr1->i1 + xscr2->i1;
 564                         i2 = xscr2->i2;
 565                         chg0 = xscr2->chg1;
 566                         chg1 = xscr2->chg1;
 567                         chg2 = xscr2->chg2;
 568                         if (xdl_append_merge(&c, 2,
 569                                              i0, chg0, i1, chg1, i2, chg2)) {
 570                                 xdl_cleanup_merge(changes);
 571                                 return -1;
 572                         }
 573                         xscr2 = xscr2->next;
 574                         continue;
 575                 }
 576                 if (level == XDL_MERGE_MINIMAL || xscr1->i1 != xscr2->i1 ||
 577                                 xscr1->chg1 != xscr2->chg1 ||
 578                                 xscr1->chg2 != xscr2->chg2 ||
 579                                 xdl_merge_cmp_lines(xe1, xscr1->i2,
 580                                         xe2, xscr2->i2,
 581                                         xscr1->chg2, xpp->flags)) {
 582                         /* conflict */
 583                         int off = xscr1->i1 - xscr2->i1;
 584                         int ffo = off + xscr1->chg1 - xscr2->chg1;
 585
 586                         i0 = xscr1->i1;
 587                         i1 = xscr1->i2;
 588                         i2 = xscr2->i2;
 589                         if (off > 0) {
 590                                 i0 -= off;
 591                                 i1 -= off;
 592                         }
 593                         else
 594                                 i2 += off;
 595                         chg0 = xscr1->i1 + xscr1->chg1 - i0;
 596                         chg1 = xscr1->i2 + xscr1->chg2 - i1;
 597                         chg2 = xscr2->i2 + xscr2->chg2 - i2;
 598                         if (ffo < 0) {
 599                                 chg0 -= ffo;
 600                                 chg1 -= ffo;
 601                         } else
 602                                 chg2 += ffo;
 603                         if (xdl_append_merge(&c, 0,
 604                                              i0, chg0, i1, chg1, i2, chg2)) {
 605                                 xdl_cleanup_merge(changes);
 606                                 return -1;
 607                         }
 608                 }
 609
 610                 i1 = xscr1->i1 + xscr1->chg1;
 611                 i2 = xscr2->i1 + xscr2->chg1;
 612
 613                 if (i1 >= i2)
 614                         xscr2 = xscr2->next;
 615                 if (i2 >= i1)
 616                         xscr1 = xscr1->next;
 617         }
 618         while (xscr1) {
 619                 if (!changes)
 620                         changes = c;
 621                 i0 = xscr1->i1;
 622                 i1 = xscr1->i2;
 623                 i2 = xscr1->i1 + xe2->xdf2.nrec - xe2->xdf1.nrec;
 624                 chg0 = xscr1->chg1;
 625                 chg1 = xscr1->chg2;
 626                 chg2 = xscr1->chg1;
 627                 if (xdl_append_merge(&c, 1,
 628                                      i0, chg0, i1, chg1, i2, chg2)) {
 629                         xdl_cleanup_merge(changes);
 630                         return -1;
 631                 }
 632                 xscr1 = xscr1->next;
 633         }
 634         while (xscr2) {
 635                 if (!changes)
 636                         changes = c;
 637                 i0 = xscr2->i1;
 638                 i1 = xscr2->i1 + xe1->xdf2.nrec - xe1->xdf1.nrec;
 639                 i2 = xscr2->i2;
 640                 chg0 = xscr2->chg1;
 641                 chg1 = xscr2->chg1;
 642                 chg2 = xscr2->chg2;
 643                 if (xdl_append_merge(&c, 2,
 644                                      i0, chg0, i1, chg1, i2, chg2)) {
 645                         xdl_cleanup_merge(changes);
 646                         return -1;
 647                 }
 648                 xscr2 = xscr2->next;
 649         }
 650         if (!changes)
 651                 changes = c;
 652         /* refine conflicts */
 653         if (XDL_MERGE_ZEALOUS <= level &&
 654             (xdl_refine_conflicts(xe1, xe2, changes, xpp) < 0 ||
 655              xdl_simplify_non_conflicts(xe1, changes,
 656                                         XDL_MERGE_ZEALOUS < level) < 0)) {
 657                 xdl_cleanup_merge(changes);
 658                 return -1;
 659         }
 660         /* output */
 661         if (result) {
 662                 int marker_size = xmp->marker_size;
 663                 size_t size;
 664
 665                 if (xdl_fill_merge_buffer(&size, xe1, name1, xe2, name2,
 666                                                  ancestor_name,
 667                                                  favor, changes, NULL, style,
 668                                                  marker_size) < 0)
 669                         return -1;
 670
 671                 result->ptr = xdl_malloc(size);
 672                 if (!result->ptr) {
 673                         xdl_cleanup_merge(changes);
 674                         return -1;
 675                 }
 676                 result->size = size;
 677                 if (xdl_fill_merge_buffer(&size, xe1, name1, xe2, name2,
 678                                       ancestor_name, favor, changes,
 679                                       result->ptr, style, marker_size) < 0)
 680                         return -1;
 681         }
 682         return xdl_cleanup_merge(changes);
 683 }
 684
 685 int xdl_merge(mmfile_t *orig, mmfile_t *mf1, mmfile_t *mf2,
 686                 xmparam_t const *xmp, mmbuffer_t *result)
 687 {
 688         xdchange_t *xscr1, *xscr2;
 689         xdfenv_t xe1, xe2;
 690         int status;
 691         xpparam_t const *xpp = &xmp->xpp;
 692
 693         result->ptr = NULL;
 694         result->size = 0;
 695
 696         if (xdl_do_diff(orig, mf1, xpp, &xe1) < 0) {
 697                 return -1;
 698         }
 699         if (xdl_do_diff(orig, mf2, xpp, &xe2) < 0) {
 700                 xdl_free_env(&xe1);
 701                 return -1;
 702         }
 703         if (xdl_change_compact(&xe1.xdf1, &xe1.xdf2, xpp->flags) < 0 ||
 704             xdl_change_compact(&xe1.xdf2, &xe1.xdf1, xpp->flags) < 0 ||
 705             xdl_build_script(&xe1, &xscr1) < 0) {
 706                 xdl_free_env(&xe1);
 707                 return -1;
 708         }
 709         if (xdl_change_compact(&xe2.xdf1, &xe2.xdf2, xpp->flags) < 0 ||
 710             xdl_change_compact(&xe2.xdf2, &xe2.xdf1, xpp->flags) < 0 ||
 711             xdl_build_script(&xe2, &xscr2) < 0) {
 712                 xdl_free_script(xscr1);
 713                 xdl_free_env(&xe1);
 714                 xdl_free_env(&xe2);
 715                 return -1;
 716         }
 717         status = 0;
 718         if (!xscr1) {
 719                 result->ptr = xdl_malloc(mf2->size);
 720                 memcpy(result->ptr, mf2->ptr, mf2->size);
 721                 result->size = mf2->size;
 722         } else if (!xscr2) {
 723                 result->ptr = xdl_malloc(mf1->size);
 724                 memcpy(result->ptr, mf1->ptr, mf1->size);
 725                 result->size = mf1->size;
 726         } else {
 727                 status = xdl_do_merge(&xe1, xscr1,
 728                                       &xe2, xscr2,
 729                                       xmp, result);
 730         }
 731         xdl_free_script(xscr1);
 732         xdl_free_script(xscr2);
 733
 734         xdl_free_env(&xe1);
 735         xdl_free_env(&xe2);
 736
 737         return status;
 738 }