combine-diff.c

   1 #include "cache.h"
   2 #include "commit.h"
   3 #include "blob.h"
   4 #include "diff.h"
   5 #include "diffcore.h"
   6 #include "quote.h"
   7 #include "xdiff-interface.h"
   8
   9 static int uninteresting(struct diff_filepair *p)
  10 {
  11         if (diff_unmodified_pair(p))
  12                 return 1;
  13         return 0;
  14 }
  15
  16 static struct combine_diff_path *intersect_paths(struct combine_diff_path *curr, int n, int num_parent)
  17 {
  18         struct diff_queue_struct *q = &diff_queued_diff;
  19         struct combine_diff_path *p;
  20         int i;
  21
  22         if (!n) {
  23                 struct combine_diff_path *list = NULL, **tail = &list;
  24                 for (i = 0; i < q->nr; i++) {
  25                         int len;
  26                         const char *path;
  27                         if (uninteresting(q->queue[i]))
  28                                 continue;
  29                         path = q->queue[i]->two->path;
  30                         len = strlen(path);
  31                         p = xmalloc(combine_diff_path_size(num_parent, len));
  32                         p->path = (char*) &(p->parent[num_parent]);
  33                         memcpy(p->path, path, len);
  34                         p->path[len] = 0;
  35                         p->len = len;
  36                         p->next = NULL;
  37                         memset(p->parent, 0,
  38                                sizeof(p->parent[0]) * num_parent);
  39
  40                         memcpy(p->sha1, q->queue[i]->two->sha1, 20);
  41                         p->mode = q->queue[i]->two->mode;
  42                         memcpy(p->parent[n].sha1, q->queue[i]->one->sha1, 20);
  43                         p->parent[n].mode = q->queue[i]->one->mode;
  44                         p->parent[n].status = q->queue[i]->status;
  45                         *tail = p;
  46                         tail = &p->next;
  47                 }
  48                 return list;
  49         }
  50
  51         for (p = curr; p; p = p->next) {
  52                 int found = 0;
  53                 if (!p->len)
  54                         continue;
  55                 for (i = 0; i < q->nr; i++) {
  56                         const char *path;
  57                         int len;
  58
  59                         if (uninteresting(q->queue[i]))
  60                                 continue;
  61                         path = q->queue[i]->two->path;
  62                         len = strlen(path);
  63                         if (len == p->len && !memcmp(path, p->path, len)) {
  64                                 found = 1;
  65                                 memcpy(p->parent[n].sha1,
  66                                        q->queue[i]->one->sha1, 20);
  67                                 p->parent[n].mode = q->queue[i]->one->mode;
  68                                 p->parent[n].status = q->queue[i]->status;
  69                                 break;
  70                         }
  71                 }
  72                 if (!found)
  73                         p->len = 0;
  74         }
  75         return curr;
  76 }
  77
  78 /* Lines lost from parent */
  79 struct lline {
  80         struct lline *next;
  81         int len;
  82         unsigned long parent_map;
  83         char line[FLEX_ARRAY];
  84 };
  85
  86 /* Lines surviving in the merge result */
  87 struct sline {
  88         struct lline *lost_head, **lost_tail;
  89         char *bol;
  90         int len;
  91         /* bit 0 up to (N-1) are on if the parent has this line (i.e.
  92          * we did not change it).
  93          * bit N is used for "interesting" lines, including context.
  94          */
  95         unsigned long flag;
  96         unsigned long *p_lno;
  97 };
  98
  99 static char *grab_blob(const unsigned char *sha1, unsigned long *size)
 100 {
 101         char *blob;
 102         char type[20];
 103         if (!memcmp(sha1, null_sha1, 20)) {
 104                 /* deleted blob */
 105                 *size = 0;
 106                 return xcalloc(1, 1);
 107         }
 108         blob = read_sha1_file(sha1, type, size);
 109         if (strcmp(type, blob_type))
 110                 die("object '%s' is not a blob!", sha1_to_hex(sha1));
 111         return blob;
 112 }
 113
 114 static void append_lost(struct sline *sline, int n, const char *line, int len)
 115 {
 116         struct lline *lline;
 117         unsigned long this_mask = (1UL<<n);
 118         if (line[len-1] == '\n')
 119                 len--;
 120
 121         /* Check to see if we can squash things */
 122         if (sline->lost_head) {
 123                 struct lline *last_one = NULL;
 124                 /* We cannot squash it with earlier one */
 125                 for (lline = sline->lost_head;
 126                      lline;
 127                      lline = lline->next)
 128                         if (lline->parent_map & this_mask)
 129                                 last_one = lline;
 130                 lline = last_one ? last_one->next : sline->lost_head;
 131                 while (lline) {
 132                         if (lline->len == len &&
 133                             !memcmp(lline->line, line, len)) {
 134                                 lline->parent_map |= this_mask;
 135                                 return;
 136                         }
 137                         lline = lline->next;
 138                 }
 139         }
 140
 141         lline = xmalloc(sizeof(*lline) + len + 1);
 142         lline->len = len;
 143         lline->next = NULL;
 144         lline->parent_map = this_mask;
 145         memcpy(lline->line, line, len);
 146         lline->line[len] = 0;
 147         *sline->lost_tail = lline;
 148         sline->lost_tail = &lline->next;
 149 }
 150
 151 struct combine_diff_state {
 152         struct xdiff_emit_state xm;
 153
 154         unsigned int lno;
 155         int ob, on, nb, nn;
 156         unsigned long nmask;
 157         int num_parent;
 158         int n;
 159         struct sline *sline;
 160         struct sline *lost_bucket;
 161 };
 162
 163 static void consume_line(void *state_, char *line, unsigned long len)
 164 {
 165         struct combine_diff_state *state = state_;
 166         if (5 < len && !memcmp("@@ -", line, 4)) {
 167                 if (parse_hunk_header(line, len,
 168                                       &state->ob, &state->on,
 169                                       &state->nb, &state->nn))
 170                         return;
 171                 state->lno = state->nb;
 172                 if (!state->nb)
 173                         /* @@ -1,2 +0,0 @@ to remove the
 174                          * first two lines...
 175                          */
 176                         state->nb = 1;
 177                 if (state->nn == 0)
 178                         /* @@ -X,Y +N,0 @@ removed Y lines
 179                          * that would have come *after* line N
 180                          * in the result.  Our lost buckets hang
 181                          * to the line after the removed lines,
 182                          */
 183                         state->lost_bucket = &state->sline[state->nb];
 184                 else
 185                         state->lost_bucket = &state->sline[state->nb-1];
 186                 if (!state->sline[state->nb-1].p_lno)
 187                         state->sline[state->nb-1].p_lno =
 188                                 xcalloc(state->num_parent,
 189                                         sizeof(unsigned long));
 190                 state->sline[state->nb-1].p_lno[state->n] = state->ob;
 191                 return;
 192         }
 193         if (!state->lost_bucket)
 194                 return; /* not in any hunk yet */
 195         switch (line[0]) {
 196         case '-':
 197                 append_lost(state->lost_bucket, state->n, line+1, len-1);
 198                 break;
 199         case '+':
 200                 state->sline[state->lno-1].flag |= state->nmask;
 201                 state->lno++;
 202                 break;
 203         }
 204 }
 205
 206 static void combine_diff(const unsigned char *parent, mmfile_t *result_file,
 207                          struct sline *sline, int cnt, int n, int num_parent)
 208 {
 209         unsigned int p_lno, lno;
 210         unsigned long nmask = (1UL << n);
 211         xpparam_t xpp;
 212         xdemitconf_t xecfg;
 213         mmfile_t parent_file;
 214         xdemitcb_t ecb;
 215         struct combine_diff_state state;
 216         unsigned long sz;
 217
 218         if (!cnt)
 219                 return; /* result deleted */
 220
 221         parent_file.ptr = grab_blob(parent, &sz);
 222         parent_file.size = sz;
 223         xpp.flags = XDF_NEED_MINIMAL;
 224         xecfg.ctxlen = 0;
 225         xecfg.flags = 0;
 226         ecb.outf = xdiff_outf;
 227         ecb.priv = &state;
 228         memset(&state, 0, sizeof(state));
 229         state.xm.consume = consume_line;
 230         state.nmask = nmask;
 231         state.sline = sline;
 232         state.lno = 1;
 233         state.num_parent = num_parent;
 234         state.n = n;
 235
 236         xdl_diff(&parent_file, result_file, &xpp, &xecfg, &ecb);
 237         free(parent_file.ptr);
 238
 239         /* Assign line numbers for this parent.
 240          *
 241          * sline[lno].p_lno[n] records the first line number
 242          * (counting from 1) for parent N if the final hunk display
 243          * started by showing sline[lno] (possibly showing the lost
 244          * lines attached to it first).
 245          */
 246         for (lno = 0,  p_lno = 1; lno <= cnt; lno++) {
 247                 struct lline *ll;
 248                 sline[lno].p_lno[n] = p_lno;
 249
 250                 /* How many lines would this sline advance the p_lno? */
 251                 ll = sline[lno].lost_head;
 252                 while (ll) {
 253                         if (ll->parent_map & nmask)
 254                                 p_lno++; /* '-' means parent had it */
 255                         ll = ll->next;
 256                 }
 257                 if (lno < cnt && !(sline[lno].flag & nmask))
 258                         p_lno++; /* no '+' means parent had it */
 259         }
 260         sline[lno].p_lno[n] = p_lno; /* trailer */
 261 }
 262
 263 static unsigned long context = 3;
 264 static char combine_marker = '@';
 265
 266 static int interesting(struct sline *sline, unsigned long all_mask)
 267 {
 268         /* If some parents lost lines here, or if we have added to
 269          * some parent, it is interesting.
 270          */
 271         return ((sline->flag & all_mask) || sline->lost_head);
 272 }
 273
 274 static unsigned long adjust_hunk_tail(struct sline *sline,
 275                                       unsigned long all_mask,
 276                                       unsigned long hunk_begin,
 277                                       unsigned long i)
 278 {
 279         /* i points at the first uninteresting line.  If the last line
 280          * of the hunk was interesting only because it has some
 281          * deletion, then it is not all that interesting for the
 282          * purpose of giving trailing context lines.  This is because
 283          * we output '-' line and then unmodified sline[i-1] itself in
 284          * that case which gives us one extra context line.
 285          */
 286         if ((hunk_begin + 1 <= i) && !(sline[i-1].flag & all_mask))
 287                 i--;
 288         return i;
 289 }
 290
 291 static unsigned long find_next(struct sline *sline,
 292                                unsigned long mark,
 293                                unsigned long i,
 294                                unsigned long cnt,
 295                                int uninteresting)
 296 {
 297         /* We have examined up to i-1 and are about to look at i.
 298          * Find next interesting or uninteresting line.  Here,
 299          * "interesting" does not mean interesting(), but marked by
 300          * the give_context() function below (i.e. it includes context
 301          * lines that are not interesting to interesting() function
 302          * that are surrounded by interesting() ones.
 303          */
 304         while (i < cnt)
 305                 if (uninteresting
 306                     ? !(sline[i].flag & mark)
 307                     : (sline[i].flag & mark))
 308                         return i;
 309                 else
 310                         i++;
 311         return cnt;
 312 }
 313
 314 static int give_context(struct sline *sline, unsigned long cnt, int num_parent)
 315 {
 316         unsigned long all_mask = (1UL<<num_parent) - 1;
 317         unsigned long mark = (1UL<<num_parent);
 318         unsigned long i;
 319
 320         /* Two groups of interesting lines may have a short gap of
 321          * unintersting lines.  Connect such groups to give them a
 322          * bit of context.
 323          *
 324          * We first start from what the interesting() function says,
 325          * and mark them with "mark", and paint context lines with the
 326          * mark.  So interesting() would still say false for such context
 327          * lines but they are treated as "interesting" in the end.
 328          */
 329         i = find_next(sline, mark, 0, cnt, 0);
 330         if (cnt <= i)
 331                 return 0;
 332
 333         while (i < cnt) {
 334                 unsigned long j = (context < i) ? (i - context) : 0;
 335                 unsigned long k;
 336
 337                 /* Paint a few lines before the first interesting line. */
 338                 while (j < i)
 339                         sline[j++].flag |= mark;
 340
 341         again:
 342                 /* we know up to i is to be included.  where does the
 343                  * next uninteresting one start?
 344                  */
 345                 j = find_next(sline, mark, i, cnt, 1);
 346                 if (cnt <= j)
 347                         break; /* the rest are all interesting */
 348
 349                 /* lookahead context lines */
 350                 k = find_next(sline, mark, j, cnt, 0);
 351                 j = adjust_hunk_tail(sline, all_mask, i, j);
 352
 353                 if (k < j + context) {
 354                         /* k is interesting and [j,k) are not, but
 355                          * paint them interesting because the gap is small.
 356                          */
 357                         while (j < k)
 358                                 sline[j++].flag |= mark;
 359                         i = k;
 360                         goto again;
 361                 }
 362
 363                 /* j is the first uninteresting line and there is
 364                  * no overlap beyond it within context lines.  Paint
 365                  * the trailing edge a bit.
 366                  */
 367                 i = k;
 368                 k = (j + context < cnt) ? j + context : cnt;
 369                 while (j < k)
 370                         sline[j++].flag |= mark;
 371         }
 372         return 1;
 373 }
 374
 375 static int make_hunks(struct sline *sline, unsigned long cnt,
 376                        int num_parent, int dense)
 377 {
 378         unsigned long all_mask = (1UL<<num_parent) - 1;
 379         unsigned long mark = (1UL<<num_parent);
 380         unsigned long i;
 381         int has_interesting = 0;
 382
 383         for (i = 0; i < cnt; i++) {
 384                 if (interesting(&sline[i], all_mask))
 385                         sline[i].flag |= mark;
 386                 else
 387                         sline[i].flag &= ~mark;
 388         }
 389         if (!dense)
 390                 return give_context(sline, cnt, num_parent);
 391
 392         /* Look at each hunk, and if we have changes from only one
 393          * parent, or the changes are the same from all but one
 394          * parent, mark that uninteresting.
 395          */
 396         i = 0;
 397         while (i < cnt) {
 398                 unsigned long j, hunk_begin, hunk_end;
 399                 unsigned long same_diff;
 400                 while (i < cnt && !(sline[i].flag & mark))
 401                         i++;
 402                 if (cnt <= i)
 403                         break; /* No more interesting hunks */
 404                 hunk_begin = i;
 405                 for (j = i + 1; j < cnt; j++) {
 406                         if (!(sline[j].flag & mark)) {
 407                                 /* Look beyond the end to see if there
 408                                  * is an interesting line after this
 409                                  * hunk within context span.
 410                                  */
 411                                 unsigned long la; /* lookahead */
 412                                 int contin = 0;
 413                                 la = adjust_hunk_tail(sline, all_mask,
 414                                                      hunk_begin, j);
 415                                 la = (la + context < cnt) ?
 416                                         (la + context) : cnt;
 417                                 while (j <= --la) {
 418                                         if (sline[la].flag & mark) {
 419                                                 contin = 1;
 420                                                 break;
 421                                         }
 422                                 }
 423                                 if (!contin)
 424                                         break;
 425                                 j = la;
 426                         }
 427                 }
 428                 hunk_end = j;
 429
 430                 /* [i..hunk_end) are interesting.  Now is it really
 431                  * interesting?  We check if there are only two versions
 432                  * and the result matches one of them.  That is, we look
 433                  * at:
 434                  *   (+) line, which records lines added to which parents;
 435                  *       this line appears in the result.
 436                  *   (-) line, which records from what parents the line
 437                  *       was removed; this line does not appear in the result.
 438                  * then check the set of parents the result has difference
 439                  * from, from all lines.  If there are lines that has
 440                  * different set of parents that the result has differences
 441                  * from, that means we have more than two versions.
 442                  *
 443                  * Even when we have only two versions, if the result does
 444                  * not match any of the parents, the it should be considered
 445                  * interesting.  In such a case, we would have all '+' line.
 446                  * After passing the above "two versions" test, that would
 447                  * appear as "the same set of parents" to be "all parents".
 448                  */
 449                 same_diff = 0;
 450                 has_interesting = 0;
 451                 for (j = i; j < hunk_end && !has_interesting; j++) {
 452                         unsigned long this_diff = sline[j].flag & all_mask;
 453                         struct lline *ll = sline[j].lost_head;
 454                         if (this_diff) {
 455                                 /* This has some changes.  Is it the
 456                                  * same as others?
 457                                  */
 458                                 if (!same_diff)
 459                                         same_diff = this_diff;
 460                                 else if (same_diff != this_diff) {
 461                                         has_interesting = 1;
 462                                         break;
 463                                 }
 464                         }
 465                         while (ll && !has_interesting) {
 466                                 /* Lost this line from these parents;
 467                                  * who are they?  Are they the same?
 468                                  */
 469                                 this_diff = ll->parent_map;
 470                                 if (!same_diff)
 471                                         same_diff = this_diff;
 472                                 else if (same_diff != this_diff) {
 473                                         has_interesting = 1;
 474                                 }
 475                                 ll = ll->next;
 476                         }
 477                 }
 478
 479                 if (!has_interesting && same_diff != all_mask) {
 480                         /* This hunk is not that interesting after all */
 481                         for (j = hunk_begin; j < hunk_end; j++)
 482                                 sline[j].flag &= ~mark;
 483                 }
 484                 i = hunk_end;
 485         }
 486
 487         has_interesting = give_context(sline, cnt, num_parent);
 488         return has_interesting;
 489 }
 490
 491 static void show_parent_lno(struct sline *sline, unsigned long l0, unsigned long l1, unsigned long cnt, int n)
 492 {
 493         l0 = sline[l0].p_lno[n];
 494         l1 = sline[l1].p_lno[n];
 495         printf(" -%lu,%lu", l0, l1-l0);
 496 }
 497
 498 static void dump_sline(struct sline *sline, unsigned long cnt, int num_parent)
 499 {
 500         unsigned long mark = (1UL<<num_parent);
 501         int i;
 502         unsigned long lno = 0;
 503
 504         if (!cnt)
 505                 return; /* result deleted */
 506
 507         while (1) {
 508                 struct sline *sl = &sline[lno];
 509                 int hunk_end;
 510                 while (lno < cnt && !(sline[lno].flag & mark))
 511                         lno++;
 512                 if (cnt < lno)
 513                         break;
 514                 else if (cnt == lno) {
 515                         /* See if there is anything interesting */
 516                         struct lline *ll;
 517                         for (ll = sline[lno].lost_head; ll; ll = ll->next)
 518                                 if (ll->parent_map)
 519                                         break;
 520                         if (!ll)
 521                                 break;
 522                         hunk_end = cnt + 1;
 523                 }
 524                 else {
 525                         for (hunk_end = lno + 1; hunk_end < cnt; hunk_end++)
 526                                 if (!(sline[hunk_end].flag & mark))
 527                                         break;
 528                 }
 529                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 530                 for (i = 0; i < num_parent; i++)
 531                         show_parent_lno(sline, lno, hunk_end, cnt, i);
 532                 printf(" +%lu,%lu ", lno+1,
 533                        (cnt == lno) ? 0 : hunk_end - lno);
 534                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 535                 putchar('\n');
 536                 while (lno < hunk_end) {
 537                         struct lline *ll;
 538                         int j;
 539                         unsigned long p_mask;
 540                         sl = &sline[lno++];
 541                         ll = sl->lost_head;
 542                         while (ll) {
 543                                 for (j = 0; j < num_parent; j++) {
 544                                         if (ll->parent_map & (1UL<<j))
 545                                                 putchar('-');
 546                                         else
 547                                                 putchar(' ');
 548                                 }
 549                                 puts(ll->line);
 550                                 ll = ll->next;
 551                         }
 552                         if (cnt <= lno)
 553                                 break;
 554                         p_mask = 1;
 555                         for (j = 0; j < num_parent; j++) {
 556                                 if (p_mask & sl->flag)
 557                                         putchar('+');
 558                                 else
 559                                         putchar(' ');
 560                                 p_mask <<= 1;
 561                         }
 562                         printf("%.*s\n", sl->len, sl->bol);
 563                 }
 564         }
 565 }
 566
 567 static void reuse_combine_diff(struct sline *sline, unsigned long cnt,
 568                                int i, int j)
 569 {
 570         /* We have already examined parent j and we know parent i
 571          * and parent j are the same, so reuse the combined result
 572          * of parent j for parent i.
 573          */
 574         unsigned long lno, imask, jmask;
 575         imask = (1UL<<i);
 576         jmask = (1UL<<j);
 577
 578         for (lno = 0; lno <= cnt; lno++) {
 579                 struct lline *ll = sline->lost_head;
 580                 sline->p_lno[i] = sline->p_lno[j];
 581                 while (ll) {
 582                         if (ll->parent_map & jmask)
 583                                 ll->parent_map |= imask;
 584                         ll = ll->next;
 585                 }
 586                 if (sline->flag & jmask)
 587                         sline->flag |= imask;
 588                 sline++;
 589         }
 590         /* the overall size of the file (sline[cnt]) */
 591         sline->p_lno[i] = sline->p_lno[j];
 592 }
 593
 594 static int show_patch_diff(struct combine_diff_path *elem, int num_parent,
 595                            int dense, const char *header,
 596                            struct diff_options *opt)
 597 {
 598         unsigned long result_size, cnt, lno;
 599         char *result, *cp, *ep;
 600         struct sline *sline; /* survived lines */
 601         int mode_differs = 0;
 602         int i, show_hunks, shown_header = 0;
 603         int working_tree_file = !memcmp(elem->sha1, null_sha1, 20);
 604         int abbrev = opt->full_index ? 40 : DEFAULT_ABBREV;
 605         mmfile_t result_file;
 606
 607         /* Read the result of merge first */
 608         if (!working_tree_file)
 609                 result = grab_blob(elem->sha1, &result_size);
 610         else {
 611                 /* Used by diff-tree to read from the working tree */
 612                 struct stat st;
 613                 int fd;
 614                 if (0 <= (fd = open(elem->path, O_RDONLY)) &&
 615                     !fstat(fd, &st)) {
 616                         int len = st.st_size;
 617                         int cnt = 0;
 618
 619                         elem->mode = canon_mode(st.st_mode);
 620                         result_size = len;
 621                         result = xmalloc(len + 1);
 622                         while (cnt < len) {
 623                                 int done = xread(fd, result+cnt, len-cnt);
 624                                 if (done == 0)
 625                                         break;
 626                                 if (done < 0)
 627                                         die("read error '%s'", elem->path);
 628                                 cnt += done;
 629                         }
 630                         result[len] = 0;
 631                 }
 632                 else {
 633                         /* deleted file */
 634                         result_size = 0;
 635                         elem->mode = 0;
 636                         result = xmalloc(1);
 637                         result[0] = 0;
 638                 }
 639                 if (0 <= fd)
 640                         close(fd);
 641         }
 642
 643         for (cnt = 0, cp = result; cp - result < result_size; cp++) {
 644                 if (*cp == '\n')
 645                         cnt++;
 646         }
 647         if (result_size && result[result_size-1] != '\n')
 648                 cnt++; /* incomplete line */
 649
 650         sline = xcalloc(cnt+2, sizeof(*sline));
 651         ep = result;
 652         sline[0].bol = result;
 653         for (lno = 0; lno <= cnt + 1; lno++) {
 654                 sline[lno].lost_tail = &sline[lno].lost_head;
 655                 sline[lno].flag = 0;
 656         }
 657         for (lno = 0, cp = result; cp - result < result_size; cp++) {
 658                 if (*cp == '\n') {
 659                         sline[lno].len = cp - sline[lno].bol;
 660                         lno++;
 661                         if (lno < cnt)
 662                                 sline[lno].bol = cp + 1;
 663                 }
 664         }
 665         if (result_size && result[result_size-1] != '\n')
 666                 sline[cnt-1].len = result_size - (sline[cnt-1].bol - result);
 667
 668         result_file.ptr = result;
 669         result_file.size = result_size;
 670
 671         /* Even p_lno[cnt+1] is valid -- that is for the end line number
 672          * for deletion hunk at the end.
 673          */
 674         sline[0].p_lno = xcalloc((cnt+2) * num_parent, sizeof(unsigned long));
 675         for (lno = 0; lno <= cnt; lno++)
 676                 sline[lno+1].p_lno = sline[lno].p_lno + num_parent;
 677
 678         for (i = 0; i < num_parent; i++) {
 679                 int j;
 680                 for (j = 0; j < i; j++) {
 681                         if (!memcmp(elem->parent[i].sha1,
 682                                     elem->parent[j].sha1, 20)) {
 683                                 reuse_combine_diff(sline, cnt, i, j);
 684                                 break;
 685                         }
 686                 }
 687                 if (i <= j)
 688                         combine_diff(elem->parent[i].sha1, &result_file, sline,
 689                                      cnt, i, num_parent);
 690                 if (elem->parent[i].mode != elem->mode)
 691                         mode_differs = 1;
 692         }
 693
 694         show_hunks = make_hunks(sline, cnt, num_parent, dense);
 695
 696         if (show_hunks || mode_differs || working_tree_file) {
 697                 const char *abb;
 698
 699                 if (header) {
 700                         shown_header++;
 701                         printf("%s%c", header, opt->line_termination);
 702                 }
 703                 printf("diff --%s ", dense ? "cc" : "combined");
 704                 if (quote_c_style(elem->path, NULL, NULL, 0))
 705                         quote_c_style(elem->path, NULL, stdout, 0);
 706                 else
 707                         printf("%s", elem->path);
 708                 putchar('\n');
 709                 printf("index ");
 710                 for (i = 0; i < num_parent; i++) {
 711                         abb = find_unique_abbrev(elem->parent[i].sha1,
 712                                                  abbrev);
 713                         printf("%s%s", i ? "," : "", abb);
 714                 }
 715                 abb = find_unique_abbrev(elem->sha1, abbrev);
 716                 printf("..%s\n", abb);
 717
 718                 if (mode_differs) {
 719                         int added = !!elem->mode;
 720                         for (i = 0; added && i < num_parent; i++)
 721                                 if (elem->parent[i].status !=
 722                                     DIFF_STATUS_ADDED)
 723                                         added = 0;
 724                         if (added)
 725                                 printf("new file mode %06o", elem->mode);
 726                         else {
 727                                 if (!elem->mode)
 728                                         printf("deleted file ");
 729                                 printf("mode ");
 730                                 for (i = 0; i < num_parent; i++) {
 731                                         printf("%s%06o", i ? "," : "",
 732                                                elem->parent[i].mode);
 733                                 }
 734                                 if (elem->mode)
 735                                         printf("..%06o", elem->mode);
 736                         }
 737                         putchar('\n');
 738                 }
 739                 dump_sline(sline, cnt, num_parent);
 740         }
 741         free(result);
 742
 743         for (i = 0; i < cnt; i++) {
 744                 if (sline[i].lost_head) {
 745                         struct lline *ll = sline[i].lost_head;
 746                         while (ll) {
 747                                 struct lline *tmp = ll;
 748                                 ll = ll->next;
 749                                 free(tmp);
 750                         }
 751                 }
 752         }
 753         free(sline[0].p_lno);
 754         free(sline);
 755         return shown_header;
 756 }
 757
 758 #define COLONS "::::::::::::::::::::::::::::::::"
 759
 760 static void show_raw_diff(struct combine_diff_path *p, int num_parent, const char *header, struct diff_options *opt)
 761 {
 762         int i, offset, mod_type = 'A';
 763         const char *prefix;
 764         int line_termination, inter_name_termination;
 765
 766         line_termination = opt->line_termination;
 767         inter_name_termination = '\t';
 768         if (!line_termination)
 769                 inter_name_termination = 0;
 770
 771         if (header)
 772                 printf("%s%c", header, line_termination);
 773
 774         for (i = 0; i < num_parent; i++) {
 775                 if (p->parent[i].mode)
 776                         mod_type = 'M';
 777         }
 778         if (!p->mode)
 779                 mod_type = 'D';
 780
 781         if (opt->output_format == DIFF_FORMAT_RAW) {
 782                 offset = strlen(COLONS) - num_parent;
 783                 if (offset < 0)
 784                         offset = 0;
 785                 prefix = COLONS + offset;
 786
 787                 /* Show the modes */
 788                 for (i = 0; i < num_parent; i++) {
 789                         printf("%s%06o", prefix, p->parent[i].mode);
 790                         prefix = " ";
 791                 }
 792                 printf("%s%06o", prefix, p->mode);
 793
 794                 /* Show sha1's */
 795                 for (i = 0; i < num_parent; i++)
 796                         printf(" %s", diff_unique_abbrev(p->parent[i].sha1,
 797                                                          opt->abbrev));
 798                 printf(" %s ", diff_unique_abbrev(p->sha1, opt->abbrev));
 799         }
 800
 801         if (opt->output_format == DIFF_FORMAT_RAW ||
 802             opt->output_format == DIFF_FORMAT_NAME_STATUS) {
 803                 for (i = 0; i < num_parent; i++)
 804                         putchar(p->parent[i].status);
 805                 putchar(inter_name_termination);
 806         }
 807
 808         if (line_termination) {
 809                 if (quote_c_style(p->path, NULL, NULL, 0))
 810                         quote_c_style(p->path, NULL, stdout, 0);
 811                 else
 812                         printf("%s", p->path);
 813                 putchar(line_termination);
 814         }
 815         else {
 816                 printf("%s%c", p->path, line_termination);
 817         }
 818 }
 819
 820 int show_combined_diff(struct combine_diff_path *p,
 821                        int num_parent,
 822                        int dense,
 823                        const char *header,
 824                        struct diff_options *opt)
 825 {
 826         if (!p->len)
 827                 return 0;
 828         switch (opt->output_format) {
 829         case DIFF_FORMAT_RAW:
 830         case DIFF_FORMAT_NAME_STATUS:
 831         case DIFF_FORMAT_NAME:
 832                 show_raw_diff(p, num_parent, header, opt);
 833                 return 1;
 834
 835         default:
 836         case DIFF_FORMAT_PATCH:
 837                 return show_patch_diff(p, num_parent, dense, header, opt);
 838         }
 839 }
 840
 841 const char *diff_tree_combined_merge(const unsigned char *sha1,
 842                              const char *header, int dense,
 843                              struct diff_options *opt)
 844 {
 845         struct commit *commit = lookup_commit(sha1);
 846         struct diff_options diffopts;
 847         struct commit_list *parents;
 848         struct combine_diff_path *p, *paths = NULL;
 849         int num_parent, i, num_paths;
 850
 851         diffopts = *opt;
 852         diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
 853         diffopts.recursive = 1;
 854
 855         /* count parents */
 856         for (parents = commit->parents, num_parent = 0;
 857              parents;
 858              parents = parents->next, num_parent++)
 859                 ; /* nothing */
 860
 861         /* find set of paths that everybody touches */
 862         for (parents = commit->parents, i = 0;
 863              parents;
 864              parents = parents->next, i++) {
 865                 struct commit *parent = parents->item;
 866                 diff_tree_sha1(parent->object.sha1, commit->object.sha1, "",
 867                                &diffopts);
 868                 diffcore_std(&diffopts);
 869                 paths = intersect_paths(paths, i, num_parent);
 870                 diff_flush(&diffopts);
 871         }
 872
 873         /* find out surviving paths */
 874         for (num_paths = 0, p = paths; p; p = p->next) {
 875                 if (p->len)
 876                         num_paths++;
 877         }
 878         if (num_paths) {
 879                 for (p = paths; p; p = p->next) {
 880                         if (show_combined_diff(p, num_parent, dense,
 881                                                header, opt))
 882                                 header = NULL;
 883                 }
 884         }
 885
 886         /* Clean things up */
 887         while (paths) {
 888                 struct combine_diff_path *tmp = paths;
 889                 paths = paths->next;
 890                 free(tmp);
 891         }
 892         return header;
 893 }