xdiff / xmerge.con commit regex: use regexec_buf() (b7d36ff)
   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, 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
  25typedef 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
  50static 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
  81static 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
  96static 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
 112static int xdl_recs_copy_0(int use_orig, xdfenv_t *xe, int i, int count, int needs_cr, int add_nl, char *dest)
 113{
 114        xrecord_t **recs;
 115        int size = 0;
 116
 117        recs = (use_orig ? xe->xdf1.recs : xe->xdf2.recs) + i;
 118
 119        if (count < 1)
 120                return 0;
 121
 122        for (i = 0; i < count; size += recs[i++]->size)
 123                if (dest)
 124                        memcpy(dest + size, recs[i]->ptr, recs[i]->size);
 125        if (add_nl) {
 126                i = recs[count - 1]->size;
 127                if (i == 0 || recs[count - 1]->ptr[i - 1] != '\n') {
 128                        if (needs_cr) {
 129                                if (dest)
 130                                        dest[size] = '\r';
 131                                size++;
 132                        }
 133
 134                        if (dest)
 135                                dest[size] = '\n';
 136                        size++;
 137                }
 138        }
 139        return size;
 140}
 141
 142static int xdl_recs_copy(xdfenv_t *xe, int i, int count, int needs_cr, int add_nl, char *dest)
 143{
 144        return xdl_recs_copy_0(0, xe, i, count, needs_cr, add_nl, dest);
 145}
 146
 147static int xdl_orig_copy(xdfenv_t *xe, int i, int count, int needs_cr, int add_nl, char *dest)
 148{
 149        return xdl_recs_copy_0(1, xe, i, count, needs_cr, add_nl, dest);
 150}
 151
 152/*
 153 * Returns 1 if the i'th line ends in CR/LF (if it is the last line and
 154 * has no eol, the preceding line, if any), 0 if it ends in LF-only, and
 155 * -1 if the line ending cannot be determined.
 156 */
 157static int is_eol_crlf(xdfile_t *file, int i)
 158{
 159        long size;
 160
 161        if (i < file->nrec - 1)
 162                /* All lines before the last *must* end in LF */
 163                return (size = file->recs[i]->size) > 1 &&
 164                        file->recs[i]->ptr[size - 2] == '\r';
 165        if (!file->nrec)
 166                /* Cannot determine eol style from empty file */
 167                return -1;
 168        if ((size = file->recs[i]->size) &&
 169                        file->recs[i]->ptr[size - 1] == '\n')
 170                /* Last line; ends in LF; Is it CR/LF? */
 171                return size > 1 &&
 172                        file->recs[i]->ptr[size - 2] == '\r';
 173        if (!i)
 174                /* The only line has no eol */
 175                return -1;
 176        /* Determine eol from second-to-last line */
 177        return (size = file->recs[i - 1]->size) > 1 &&
 178                file->recs[i - 1]->ptr[size - 2] == '\r';
 179}
 180
 181static int is_cr_needed(xdfenv_t *xe1, xdfenv_t *xe2, xdmerge_t *m)
 182{
 183        int needs_cr;
 184
 185        /* Match post-images' preceding, or first, lines' end-of-line style */
 186        needs_cr = is_eol_crlf(&xe1->xdf2, m->i1 ? m->i1 - 1 : 0);
 187        if (needs_cr)
 188                needs_cr = is_eol_crlf(&xe2->xdf2, m->i2 ? m->i2 - 1 : 0);
 189        /* Look at pre-image's first line, unless we already settled on LF */
 190        if (needs_cr)
 191                needs_cr = is_eol_crlf(&xe1->xdf1, 0);
 192        /* If still undecided, use LF-only */
 193        return needs_cr < 0 ? 0 : needs_cr;
 194}
 195
 196static int fill_conflict_hunk(xdfenv_t *xe1, const char *name1,
 197                              xdfenv_t *xe2, const char *name2,
 198                              const char *name3,
 199                              int size, int i, int style,
 200                              xdmerge_t *m, char *dest, int marker_size)
 201{
 202        int marker1_size = (name1 ? strlen(name1) + 1 : 0);
 203        int marker2_size = (name2 ? strlen(name2) + 1 : 0);
 204        int marker3_size = (name3 ? strlen(name3) + 1 : 0);
 205        int needs_cr = is_cr_needed(xe1, xe2, m);
 206
 207        if (marker_size <= 0)
 208                marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
 209
 210        /* Before conflicting part */
 211        size += xdl_recs_copy(xe1, i, m->i1 - i, 0, 0,
 212                              dest ? dest + size : NULL);
 213
 214        if (!dest) {
 215                size += marker_size + 1 + needs_cr + marker1_size;
 216        } else {
 217                memset(dest + size, '<', marker_size);
 218                size += marker_size;
 219                if (marker1_size) {
 220                        dest[size] = ' ';
 221                        memcpy(dest + size + 1, name1, marker1_size - 1);
 222                        size += marker1_size;
 223                }
 224                if (needs_cr)
 225                        dest[size++] = '\r';
 226                dest[size++] = '\n';
 227        }
 228
 229        /* Postimage from side #1 */
 230        size += xdl_recs_copy(xe1, m->i1, m->chg1, needs_cr, 1,
 231                              dest ? dest + size : NULL);
 232
 233        if (style == XDL_MERGE_DIFF3) {
 234                /* Shared preimage */
 235                if (!dest) {
 236                        size += marker_size + 1 + needs_cr + marker3_size;
 237                } else {
 238                        memset(dest + size, '|', marker_size);
 239                        size += marker_size;
 240                        if (marker3_size) {
 241                                dest[size] = ' ';
 242                                memcpy(dest + size + 1, name3, marker3_size - 1);
 243                                size += marker3_size;
 244                        }
 245                        if (needs_cr)
 246                                dest[size++] = '\r';
 247                        dest[size++] = '\n';
 248                }
 249                size += xdl_orig_copy(xe1, m->i0, m->chg0, needs_cr, 1,
 250                                      dest ? dest + size : NULL);
 251        }
 252
 253        if (!dest) {
 254                size += marker_size + 1 + needs_cr;
 255        } else {
 256                memset(dest + size, '=', marker_size);
 257                size += marker_size;
 258                if (needs_cr)
 259                        dest[size++] = '\r';
 260                dest[size++] = '\n';
 261        }
 262
 263        /* Postimage from side #2 */
 264        size += xdl_recs_copy(xe2, m->i2, m->chg2, needs_cr, 1,
 265                              dest ? dest + size : NULL);
 266        if (!dest) {
 267                size += marker_size + 1 + needs_cr + marker2_size;
 268        } else {
 269                memset(dest + size, '>', marker_size);
 270                size += marker_size;
 271                if (marker2_size) {
 272                        dest[size] = ' ';
 273                        memcpy(dest + size + 1, name2, marker2_size - 1);
 274                        size += marker2_size;
 275                }
 276                if (needs_cr)
 277                        dest[size++] = '\r';
 278                dest[size++] = '\n';
 279        }
 280        return size;
 281}
 282
 283static int xdl_fill_merge_buffer(xdfenv_t *xe1, const char *name1,
 284                                 xdfenv_t *xe2, const char *name2,
 285                                 const char *ancestor_name,
 286                                 int favor,
 287                                 xdmerge_t *m, char *dest, int style,
 288                                 int marker_size)
 289{
 290        int size, i;
 291
 292        for (size = i = 0; m; m = m->next) {
 293                if (favor && !m->mode)
 294                        m->mode = favor;
 295
 296                if (m->mode == 0)
 297                        size = fill_conflict_hunk(xe1, name1, xe2, name2,
 298                                                  ancestor_name,
 299                                                  size, i, style, m, dest,
 300                                                  marker_size);
 301                else if (m->mode & 3) {
 302                        /* Before conflicting part */
 303                        size += xdl_recs_copy(xe1, i, m->i1 - i, 0, 0,
 304                                              dest ? dest + size : NULL);
 305                        /* Postimage from side #1 */
 306                        if (m->mode & 1) {
 307                                int needs_cr = is_cr_needed(xe1, xe2, m);
 308
 309                                size += xdl_recs_copy(xe1, m->i1, m->chg1, needs_cr, (m->mode & 2),
 310                                                      dest ? dest + size : NULL);
 311                        }
 312                        /* Postimage from side #2 */
 313                        if (m->mode & 2)
 314                                size += xdl_recs_copy(xe2, m->i2, m->chg2, 0, 0,
 315                                                      dest ? dest + size : NULL);
 316                } else
 317                        continue;
 318                i = m->i1 + m->chg1;
 319        }
 320        size += xdl_recs_copy(xe1, i, xe1->xdf2.nrec - i, 0, 0,
 321                              dest ? dest + size : NULL);
 322        return size;
 323}
 324
 325/*
 326 * Sometimes, changes are not quite identical, but differ in only a few
 327 * lines. Try hard to show only these few lines as conflicting.
 328 */
 329static int xdl_refine_conflicts(xdfenv_t *xe1, xdfenv_t *xe2, xdmerge_t *m,
 330                xpparam_t const *xpp)
 331{
 332        for (; m; m = m->next) {
 333                mmfile_t t1, t2;
 334                xdfenv_t xe;
 335                xdchange_t *xscr, *x;
 336                int i1 = m->i1, i2 = m->i2;
 337
 338                /* let's handle just the conflicts */
 339                if (m->mode)
 340                        continue;
 341
 342                /* no sense refining a conflict when one side is empty */
 343                if (m->chg1 == 0 || m->chg2 == 0)
 344                        continue;
 345
 346                /*
 347                 * This probably does not work outside git, since
 348                 * we have a very simple mmfile structure.
 349                 */
 350                t1.ptr = (char *)xe1->xdf2.recs[m->i1]->ptr;
 351                t1.size = xe1->xdf2.recs[m->i1 + m->chg1 - 1]->ptr
 352                        + xe1->xdf2.recs[m->i1 + m->chg1 - 1]->size - t1.ptr;
 353                t2.ptr = (char *)xe2->xdf2.recs[m->i2]->ptr;
 354                t2.size = xe2->xdf2.recs[m->i2 + m->chg2 - 1]->ptr
 355                        + xe2->xdf2.recs[m->i2 + m->chg2 - 1]->size - t2.ptr;
 356                if (xdl_do_diff(&t1, &t2, xpp, &xe) < 0)
 357                        return -1;
 358                if (xdl_change_compact(&xe.xdf1, &xe.xdf2, xpp->flags) < 0 ||
 359                    xdl_change_compact(&xe.xdf2, &xe.xdf1, xpp->flags) < 0 ||
 360                    xdl_build_script(&xe, &xscr) < 0) {
 361                        xdl_free_env(&xe);
 362                        return -1;
 363                }
 364                if (!xscr) {
 365                        /* If this happens, the changes are identical. */
 366                        xdl_free_env(&xe);
 367                        m->mode = 4;
 368                        continue;
 369                }
 370                x = xscr;
 371                m->i1 = xscr->i1 + i1;
 372                m->chg1 = xscr->chg1;
 373                m->i2 = xscr->i2 + i2;
 374                m->chg2 = xscr->chg2;
 375                while (xscr->next) {
 376                        xdmerge_t *m2 = xdl_malloc(sizeof(xdmerge_t));
 377                        if (!m2) {
 378                                xdl_free_env(&xe);
 379                                xdl_free_script(x);
 380                                return -1;
 381                        }
 382                        xscr = xscr->next;
 383                        m2->next = m->next;
 384                        m->next = m2;
 385                        m = m2;
 386                        m->mode = 0;
 387                        m->i1 = xscr->i1 + i1;
 388                        m->chg1 = xscr->chg1;
 389                        m->i2 = xscr->i2 + i2;
 390                        m->chg2 = xscr->chg2;
 391                }
 392                xdl_free_env(&xe);
 393                xdl_free_script(x);
 394        }
 395        return 0;
 396}
 397
 398static int line_contains_alnum(const char *ptr, long size)
 399{
 400        while (size--)
 401                if (isalnum((unsigned char)*(ptr++)))
 402                        return 1;
 403        return 0;
 404}
 405
 406static int lines_contain_alnum(xdfenv_t *xe, int i, int chg)
 407{
 408        for (; chg; chg--, i++)
 409                if (line_contains_alnum(xe->xdf2.recs[i]->ptr,
 410                                xe->xdf2.recs[i]->size))
 411                        return 1;
 412        return 0;
 413}
 414
 415/*
 416 * This function merges m and m->next, marking everything between those hunks
 417 * as conflicting, too.
 418 */
 419static void xdl_merge_two_conflicts(xdmerge_t *m)
 420{
 421        xdmerge_t *next_m = m->next;
 422        m->chg1 = next_m->i1 + next_m->chg1 - m->i1;
 423        m->chg2 = next_m->i2 + next_m->chg2 - m->i2;
 424        m->next = next_m->next;
 425        free(next_m);
 426}
 427
 428/*
 429 * If there are less than 3 non-conflicting lines between conflicts,
 430 * it appears simpler -- because it takes up less (or as many) lines --
 431 * if the lines are moved into the conflicts.
 432 */
 433static int xdl_simplify_non_conflicts(xdfenv_t *xe1, xdmerge_t *m,
 434                                      int simplify_if_no_alnum)
 435{
 436        int result = 0;
 437
 438        if (!m)
 439                return result;
 440        for (;;) {
 441                xdmerge_t *next_m = m->next;
 442                int begin, end;
 443
 444                if (!next_m)
 445                        return result;
 446
 447                begin = m->i1 + m->chg1;
 448                end = next_m->i1;
 449
 450                if (m->mode != 0 || next_m->mode != 0 ||
 451                    (end - begin > 3 &&
 452                     (!simplify_if_no_alnum ||
 453                      lines_contain_alnum(xe1, begin, end - begin)))) {
 454                        m = next_m;
 455                } else {
 456                        result++;
 457                        xdl_merge_two_conflicts(m);
 458                }
 459        }
 460}
 461
 462/*
 463 * level == 0: mark all overlapping changes as conflict
 464 * level == 1: mark overlapping changes as conflict only if not identical
 465 * level == 2: analyze non-identical changes for minimal conflict set
 466 * level == 3: analyze non-identical changes for minimal conflict set, but
 467 *             treat hunks not containing any letter or number as conflicting
 468 *
 469 * returns < 0 on error, == 0 for no conflicts, else number of conflicts
 470 */
 471static int xdl_do_merge(xdfenv_t *xe1, xdchange_t *xscr1,
 472                xdfenv_t *xe2, xdchange_t *xscr2,
 473                xmparam_t const *xmp, mmbuffer_t *result)
 474{
 475        xdmerge_t *changes, *c;
 476        xpparam_t const *xpp = &xmp->xpp;
 477        const char *const ancestor_name = xmp->ancestor;
 478        const char *const name1 = xmp->file1;
 479        const char *const name2 = xmp->file2;
 480        int i0, i1, i2, chg0, chg1, chg2;
 481        int level = xmp->level;
 482        int style = xmp->style;
 483        int favor = xmp->favor;
 484
 485        if (style == XDL_MERGE_DIFF3) {
 486                /*
 487                 * "diff3 -m" output does not make sense for anything
 488                 * more aggressive than XDL_MERGE_EAGER.
 489                 */
 490                if (XDL_MERGE_EAGER < level)
 491                        level = XDL_MERGE_EAGER;
 492        }
 493
 494        c = changes = NULL;
 495
 496        while (xscr1 && xscr2) {
 497                if (!changes)
 498                        changes = c;
 499                if (xscr1->i1 + xscr1->chg1 < xscr2->i1) {
 500                        i0 = xscr1->i1;
 501                        i1 = xscr1->i2;
 502                        i2 = xscr2->i2 - xscr2->i1 + xscr1->i1;
 503                        chg0 = xscr1->chg1;
 504                        chg1 = xscr1->chg2;
 505                        chg2 = xscr1->chg1;
 506                        if (xdl_append_merge(&c, 1,
 507                                             i0, chg0, i1, chg1, i2, chg2)) {
 508                                xdl_cleanup_merge(changes);
 509                                return -1;
 510                        }
 511                        xscr1 = xscr1->next;
 512                        continue;
 513                }
 514                if (xscr2->i1 + xscr2->chg1 < xscr1->i1) {
 515                        i0 = xscr2->i1;
 516                        i1 = xscr1->i2 - xscr1->i1 + xscr2->i1;
 517                        i2 = xscr2->i2;
 518                        chg0 = xscr2->chg1;
 519                        chg1 = xscr2->chg1;
 520                        chg2 = xscr2->chg2;
 521                        if (xdl_append_merge(&c, 2,
 522                                             i0, chg0, i1, chg1, i2, chg2)) {
 523                                xdl_cleanup_merge(changes);
 524                                return -1;
 525                        }
 526                        xscr2 = xscr2->next;
 527                        continue;
 528                }
 529                if (level == XDL_MERGE_MINIMAL || xscr1->i1 != xscr2->i1 ||
 530                                xscr1->chg1 != xscr2->chg1 ||
 531                                xscr1->chg2 != xscr2->chg2 ||
 532                                xdl_merge_cmp_lines(xe1, xscr1->i2,
 533                                        xe2, xscr2->i2,
 534                                        xscr1->chg2, xpp->flags)) {
 535                        /* conflict */
 536                        int off = xscr1->i1 - xscr2->i1;
 537                        int ffo = off + xscr1->chg1 - xscr2->chg1;
 538
 539                        i0 = xscr1->i1;
 540                        i1 = xscr1->i2;
 541                        i2 = xscr2->i2;
 542                        if (off > 0) {
 543                                i0 -= off;
 544                                i1 -= off;
 545                        }
 546                        else
 547                                i2 += off;
 548                        chg0 = xscr1->i1 + xscr1->chg1 - i0;
 549                        chg1 = xscr1->i2 + xscr1->chg2 - i1;
 550                        chg2 = xscr2->i2 + xscr2->chg2 - i2;
 551                        if (ffo < 0) {
 552                                chg0 -= ffo;
 553                                chg1 -= ffo;
 554                        } else
 555                                chg2 += ffo;
 556                        if (xdl_append_merge(&c, 0,
 557                                             i0, chg0, i1, chg1, i2, chg2)) {
 558                                xdl_cleanup_merge(changes);
 559                                return -1;
 560                        }
 561                }
 562
 563                i1 = xscr1->i1 + xscr1->chg1;
 564                i2 = xscr2->i1 + xscr2->chg1;
 565
 566                if (i1 >= i2)
 567                        xscr2 = xscr2->next;
 568                if (i2 >= i1)
 569                        xscr1 = xscr1->next;
 570        }
 571        while (xscr1) {
 572                if (!changes)
 573                        changes = c;
 574                i0 = xscr1->i1;
 575                i1 = xscr1->i2;
 576                i2 = xscr1->i1 + xe2->xdf2.nrec - xe2->xdf1.nrec;
 577                chg0 = xscr1->chg1;
 578                chg1 = xscr1->chg2;
 579                chg2 = xscr1->chg1;
 580                if (xdl_append_merge(&c, 1,
 581                                     i0, chg0, i1, chg1, i2, chg2)) {
 582                        xdl_cleanup_merge(changes);
 583                        return -1;
 584                }
 585                xscr1 = xscr1->next;
 586        }
 587        while (xscr2) {
 588                if (!changes)
 589                        changes = c;
 590                i0 = xscr2->i1;
 591                i1 = xscr2->i1 + xe1->xdf2.nrec - xe1->xdf1.nrec;
 592                i2 = xscr2->i2;
 593                chg0 = xscr2->chg1;
 594                chg1 = xscr2->chg1;
 595                chg2 = xscr2->chg2;
 596                if (xdl_append_merge(&c, 2,
 597                                     i0, chg0, i1, chg1, i2, chg2)) {
 598                        xdl_cleanup_merge(changes);
 599                        return -1;
 600                }
 601                xscr2 = xscr2->next;
 602        }
 603        if (!changes)
 604                changes = c;
 605        /* refine conflicts */
 606        if (XDL_MERGE_ZEALOUS <= level &&
 607            (xdl_refine_conflicts(xe1, xe2, changes, xpp) < 0 ||
 608             xdl_simplify_non_conflicts(xe1, changes,
 609                                        XDL_MERGE_ZEALOUS < level) < 0)) {
 610                xdl_cleanup_merge(changes);
 611                return -1;
 612        }
 613        /* output */
 614        if (result) {
 615                int marker_size = xmp->marker_size;
 616                int size = xdl_fill_merge_buffer(xe1, name1, xe2, name2,
 617                                                 ancestor_name,
 618                                                 favor, changes, NULL, style,
 619                                                 marker_size);
 620                result->ptr = xdl_malloc(size);
 621                if (!result->ptr) {
 622                        xdl_cleanup_merge(changes);
 623                        return -1;
 624                }
 625                result->size = size;
 626                xdl_fill_merge_buffer(xe1, name1, xe2, name2,
 627                                      ancestor_name, favor, changes,
 628                                      result->ptr, style, marker_size);
 629        }
 630        return xdl_cleanup_merge(changes);
 631}
 632
 633int xdl_merge(mmfile_t *orig, mmfile_t *mf1, mmfile_t *mf2,
 634                xmparam_t const *xmp, mmbuffer_t *result)
 635{
 636        xdchange_t *xscr1, *xscr2;
 637        xdfenv_t xe1, xe2;
 638        int status;
 639        xpparam_t const *xpp = &xmp->xpp;
 640
 641        result->ptr = NULL;
 642        result->size = 0;
 643
 644        if (xdl_do_diff(orig, mf1, xpp, &xe1) < 0) {
 645                return -1;
 646        }
 647        if (xdl_do_diff(orig, mf2, xpp, &xe2) < 0) {
 648                xdl_free_env(&xe1);
 649                return -1;
 650        }
 651        if (xdl_change_compact(&xe1.xdf1, &xe1.xdf2, xpp->flags) < 0 ||
 652            xdl_change_compact(&xe1.xdf2, &xe1.xdf1, xpp->flags) < 0 ||
 653            xdl_build_script(&xe1, &xscr1) < 0) {
 654                xdl_free_env(&xe1);
 655                return -1;
 656        }
 657        if (xdl_change_compact(&xe2.xdf1, &xe2.xdf2, xpp->flags) < 0 ||
 658            xdl_change_compact(&xe2.xdf2, &xe2.xdf1, xpp->flags) < 0 ||
 659            xdl_build_script(&xe2, &xscr2) < 0) {
 660                xdl_free_script(xscr1);
 661                xdl_free_env(&xe1);
 662                xdl_free_env(&xe2);
 663                return -1;
 664        }
 665        status = 0;
 666        if (!xscr1) {
 667                result->ptr = xdl_malloc(mf2->size);
 668                memcpy(result->ptr, mf2->ptr, mf2->size);
 669                result->size = mf2->size;
 670        } else if (!xscr2) {
 671                result->ptr = xdl_malloc(mf1->size);
 672                memcpy(result->ptr, mf1->ptr, mf1->size);
 673                result->size = mf1->size;
 674        } else {
 675                status = xdl_do_merge(&xe1, xscr1,
 676                                      &xe2, xscr2,
 677                                      xmp, result);
 678        }
 679        xdl_free_script(xscr1);
 680        xdl_free_script(xscr2);
 681
 682        xdl_free_env(&xe1);
 683        xdl_free_env(&xe2);
 684
 685        return status;
 686}