combine-diff.c

   1 #include "cache.h"
   2 #include "commit.h"
   3 #include "diff.h"
   4 #include "diffcore.h"
   5 #include "quote.h"
   6
   7 static int uninteresting(struct diff_filepair *p)
   8 {
   9         if (diff_unmodified_pair(p))
  10                 return 1;
  11         if (!S_ISREG(p->one->mode) || !S_ISREG(p->two->mode))
  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
  32                         p = xmalloc(sizeof(*p) + len + 1 + num_parent * 20);
  33                         p->path = (char*) &(p->parent_sha1[num_parent][0]);
  34                         memcpy(p->path, path, len);
  35                         p->path[len] = 0;
  36                         p->len = len;
  37                         p->next = NULL;
  38                         memcpy(p->sha1, q->queue[i]->two->sha1, 20);
  39                         memcpy(p->parent_sha1[n], q->queue[i]->one->sha1, 20);
  40                         *tail = p;
  41                         tail = &p->next;
  42                 }
  43                 return list;
  44         }
  45
  46         for (p = curr; p; p = p->next) {
  47                 int found = 0;
  48                 if (!p->len)
  49                         continue;
  50                 for (i = 0; i < q->nr; i++) {
  51                         const char *path;
  52                         int len;
  53
  54                         if (uninteresting(q->queue[i]))
  55                                 continue;
  56                         path = q->queue[i]->two->path;
  57                         len = strlen(path);
  58                         if (len == p->len && !memcmp(path, p->path, len)) {
  59                                 found = 1;
  60                                 memcpy(p->parent_sha1[n],
  61                                        q->queue[i]->one->sha1, 20);
  62                                 break;
  63                         }
  64                 }
  65                 if (!found)
  66                         p->len = 0;
  67         }
  68         return curr;
  69 }
  70
  71 /* Lines lost from parent */
  72 struct lline {
  73         struct lline *next;
  74         int len;
  75         unsigned long parent_map;
  76         char line[FLEX_ARRAY];
  77 };
  78
  79 /* Lines surviving in the merge result */
  80 struct sline {
  81         struct lline *lost_head, **lost_tail;
  82         char *bol;
  83         int len;
  84         /* bit 0 up to (N-1) are on if the parent has this line (i.e.
  85          * we did not change it).
  86          * bit N is used for "interesting" lines, including context.
  87          */
  88         unsigned long flag;
  89         unsigned long *p_lno;
  90 };
  91
  92 static char *grab_blob(const unsigned char *sha1, unsigned long *size)
  93 {
  94         char *blob;
  95         char type[20];
  96         if (!memcmp(sha1, null_sha1, 20)) {
  97                 /* deleted blob */
  98                 *size = 0;
  99                 return xcalloc(1, 1);
 100         }
 101         blob = read_sha1_file(sha1, type, size);
 102         if (strcmp(type, "blob"))
 103                 die("object '%s' is not a blob!", sha1_to_hex(sha1));
 104         return blob;
 105 }
 106
 107 #define TMPPATHLEN 50
 108 #define MAXLINELEN 10240
 109
 110 static void write_to_temp_file(char *tmpfile, void *blob, unsigned long size)
 111 {
 112         int fd = git_mkstemp(tmpfile, TMPPATHLEN, ".diff_XXXXXX");
 113         if (fd < 0)
 114                 die("unable to create temp-file");
 115         if (write(fd, blob, size) != size)
 116                 die("unable to write temp-file");
 117         close(fd);
 118 }
 119
 120 static void write_temp_blob(char *tmpfile, const unsigned char *sha1)
 121 {
 122         unsigned long size;
 123         void *blob;
 124         blob = grab_blob(sha1, &size);
 125         write_to_temp_file(tmpfile, blob, size);
 126         free(blob);
 127 }
 128
 129 static int parse_num(char **cp_p, unsigned int *num_p)
 130 {
 131         char *cp = *cp_p;
 132         unsigned int num = 0;
 133         int read_some;
 134
 135         while ('0' <= *cp && *cp <= '9')
 136                 num = num * 10 + *cp++ - '0';
 137         if (!(read_some = cp - *cp_p))
 138                 return -1;
 139         *cp_p = cp;
 140         *num_p = num;
 141         return 0;
 142 }
 143
 144 static int parse_hunk_header(char *line, int len,
 145                              unsigned int *ob, unsigned int *on,
 146                              unsigned int *nb, unsigned int *nn)
 147 {
 148         char *cp;
 149         cp = line + 4;
 150         if (parse_num(&cp, ob)) {
 151         bad_line:
 152                 return error("malformed diff output: %s", line);
 153         }
 154         if (*cp == ',') {
 155                 cp++;
 156                 if (parse_num(&cp, on))
 157                         goto bad_line;
 158         }
 159         else
 160                 *on = 1;
 161         if (*cp++ != ' ' || *cp++ != '+')
 162                 goto bad_line;
 163         if (parse_num(&cp, nb))
 164                 goto bad_line;
 165         if (*cp == ',') {
 166                 cp++;
 167                 if (parse_num(&cp, nn))
 168                         goto bad_line;
 169         }
 170         else
 171                 *nn = 1;
 172         return -!!memcmp(cp, " @@", 3);
 173 }
 174
 175 static void append_lost(struct sline *sline, int n, const char *line)
 176 {
 177         struct lline *lline;
 178         int len = strlen(line);
 179         unsigned long this_mask = (1UL<<n);
 180         if (line[len-1] == '\n')
 181                 len--;
 182
 183         /* Check to see if we can squash things */
 184         if (sline->lost_head) {
 185                 struct lline *last_one = NULL;
 186                 /* We cannot squash it with earlier one */
 187                 for (lline = sline->lost_head;
 188                      lline;
 189                      lline = lline->next)
 190                         if (lline->parent_map & this_mask)
 191                                 last_one = lline;
 192                 lline = last_one ? last_one->next : sline->lost_head;
 193                 while (lline) {
 194                         if (lline->len == len &&
 195                             !memcmp(lline->line, line, len)) {
 196                                 lline->parent_map |= this_mask;
 197                                 return;
 198                         }
 199                         lline = lline->next;
 200                 }
 201         }
 202
 203         lline = xmalloc(sizeof(*lline) + len + 1);
 204         lline->len = len;
 205         lline->next = NULL;
 206         lline->parent_map = this_mask;
 207         memcpy(lline->line, line, len);
 208         lline->line[len] = 0;
 209         *sline->lost_tail = lline;
 210         sline->lost_tail = &lline->next;
 211 }
 212
 213 static void combine_diff(const unsigned char *parent, const char *ourtmp,
 214                          struct sline *sline, int cnt, int n, int num_parent)
 215 {
 216         FILE *in;
 217         char parent_tmp[TMPPATHLEN];
 218         char cmd[TMPPATHLEN * 2 + 1024];
 219         char line[MAXLINELEN];
 220         unsigned int lno, ob, on, nb, nn, p_lno;
 221         unsigned long nmask = (1UL << n);
 222         struct sline *lost_bucket = NULL;
 223
 224         write_temp_blob(parent_tmp, parent);
 225         sprintf(cmd, "diff --unified=0 -La/x -Lb/x '%s' '%s'",
 226                 parent_tmp, ourtmp);
 227         in = popen(cmd, "r");
 228         if (!in)
 229                 die("cannot spawn %s", cmd);
 230
 231         lno = 1;
 232         while (fgets(line, sizeof(line), in) != NULL) {
 233                 int len = strlen(line);
 234                 if (5 < len && !memcmp("@@ -", line, 4)) {
 235                         if (parse_hunk_header(line, len,
 236                                               &ob, &on, &nb, &nn))
 237                                 break;
 238                         lno = nb;
 239                         if (!nb)
 240                                 /* @@ -1,2 +0,0 @@ to remove the
 241                                  * first two lines...
 242                                  */
 243                                 nb = 1;
 244                         if (nn == 0)
 245                                 /* @@ -X,Y +N,0 @@ removed Y lines
 246                                  * that would have come *after* line N
 247                                  * in the result.  Our lost buckets hang
 248                                  * to the line after the removed lines,
 249                                  */
 250                                 lost_bucket = &sline[nb];
 251                         else
 252                                 lost_bucket = &sline[nb-1];
 253                         if (!sline[nb-1].p_lno)
 254                                 sline[nb-1].p_lno =
 255                                         xcalloc(num_parent,
 256                                                 sizeof(unsigned long));
 257                         sline[nb-1].p_lno[n] = ob;
 258                         continue;
 259                 }
 260                 if (!lost_bucket)
 261                         continue; /* not in any hunk yet */
 262                 switch (line[0]) {
 263                 case '-':
 264                         append_lost(lost_bucket, n, line+1);
 265                         break;
 266                 case '+':
 267                         sline[lno-1].flag |= nmask;
 268                         lno++;
 269                         break;
 270                 }
 271         }
 272         fclose(in);
 273         unlink(parent_tmp);
 274
 275         /* Assign line numbers for this parent.
 276          *
 277          * sline[lno].p_lno[n] records the first line number
 278          * (counting from 1) for parent N if the final hunk display
 279          * started by showing sline[lno] (possibly showing the lost
 280          * lines attached to it first).
 281          */
 282         for (lno = 0,  p_lno = 1; lno < cnt; lno++) {
 283                 struct lline *ll;
 284                 sline[lno].p_lno[n] = p_lno;
 285
 286                 /* How many lines would this sline advance the p_lno? */
 287                 ll = sline[lno].lost_head;
 288                 while (ll) {
 289                         if (ll->parent_map & nmask)
 290                                 p_lno++; /* '-' means parent had it */
 291                         ll = ll->next;
 292                 }
 293                 if (!(sline[lno].flag & nmask))
 294                         p_lno++; /* no '+' means parent had it */
 295         }
 296         sline[lno].p_lno[n] = p_lno; /* trailer */
 297 }
 298
 299 static unsigned long context = 3;
 300 static char combine_marker = '@';
 301
 302 static int interesting(struct sline *sline, unsigned long all_mask)
 303 {
 304         /* If some parents lost lines here, or if we have added to
 305          * some parent, it is interesting.
 306          */
 307         return ((sline->flag & all_mask) || sline->lost_head);
 308 }
 309
 310 static unsigned long adjust_hunk_tail(struct sline *sline,
 311                                       unsigned long all_mask,
 312                                       unsigned long hunk_begin,
 313                                       unsigned long i)
 314 {
 315         /* i points at the first uninteresting line.  If the last line
 316          * of the hunk was interesting only because it has some
 317          * deletion, then it is not all that interesting for the
 318          * purpose of giving trailing context lines.  This is because
 319          * we output '-' line and then unmodified sline[i-1] itself in
 320          * that case which gives us one extra context line.
 321          */
 322         if ((hunk_begin + 1 <= i) && !(sline[i-1].flag & all_mask))
 323                 i--;
 324         return i;
 325 }
 326
 327 static unsigned long find_next(struct sline *sline,
 328                                unsigned long mark,
 329                                unsigned long i,
 330                                unsigned long cnt,
 331                                int uninteresting)
 332 {
 333         /* We have examined up to i-1 and are about to look at i.
 334          * Find next interesting or uninteresting line.  Here,
 335          * "interesting" does not mean interesting(), but marked by
 336          * the give_context() function below (i.e. it includes context
 337          * lines that are not interesting to interesting() function
 338          * that are surrounded by interesting() ones.
 339          */
 340         while (i < cnt)
 341                 if (uninteresting
 342                     ? !(sline[i].flag & mark)
 343                     : (sline[i].flag & mark))
 344                         return i;
 345                 else
 346                         i++;
 347         return cnt;
 348 }
 349
 350 static int give_context(struct sline *sline, unsigned long cnt, int num_parent)
 351 {
 352         unsigned long all_mask = (1UL<<num_parent) - 1;
 353         unsigned long mark = (1UL<<num_parent);
 354         unsigned long i;
 355
 356         /* Two groups of interesting lines may have a short gap of
 357          * unintersting lines.  Connect such groups to give them a
 358          * bit of context.
 359          *
 360          * We first start from what the interesting() function says,
 361          * and mark them with "mark", and paint context lines with the
 362          * mark.  So interesting() would still say false for such context
 363          * lines but they are treated as "interesting" in the end.
 364          */
 365         i = find_next(sline, mark, 0, cnt, 0);
 366         if (cnt <= i)
 367                 return 0;
 368
 369         while (i < cnt) {
 370                 unsigned long j = (context < i) ? (i - context) : 0;
 371                 unsigned long k;
 372
 373                 /* Paint a few lines before the first interesting line. */
 374                 while (j < i)
 375                         sline[j++].flag |= mark;
 376
 377         again:
 378                 /* we know up to i is to be included.  where does the
 379                  * next uninteresting one start?
 380                  */
 381                 j = find_next(sline, mark, i, cnt, 1);
 382                 if (cnt <= j)
 383                         break; /* the rest are all interesting */
 384
 385                 /* lookahead context lines */
 386                 k = find_next(sline, mark, j, cnt, 0);
 387                 j = adjust_hunk_tail(sline, all_mask, i, j);
 388
 389                 if (k < j + context) {
 390                         /* k is interesting and [j,k) are not, but
 391                          * paint them interesting because the gap is small.
 392                          */
 393                         while (j < k)
 394                                 sline[j++].flag |= mark;
 395                         i = k;
 396                         goto again;
 397                 }
 398
 399                 /* j is the first uninteresting line and there is
 400                  * no overlap beyond it within context lines.  Paint
 401                  * the trailing edge a bit.
 402                  */
 403                 i = k;
 404                 k = (j + context < cnt) ? j + context : cnt;
 405                 while (j < k)
 406                         sline[j++].flag |= mark;
 407         }
 408         return 1;
 409 }
 410
 411 static int make_hunks(struct sline *sline, unsigned long cnt,
 412                        int num_parent, int dense)
 413 {
 414         unsigned long all_mask = (1UL<<num_parent) - 1;
 415         unsigned long mark = (1UL<<num_parent);
 416         unsigned long i;
 417         int has_interesting = 0;
 418
 419         for (i = 0; i < cnt; i++) {
 420                 if (interesting(&sline[i], all_mask))
 421                         sline[i].flag |= mark;
 422                 else
 423                         sline[i].flag &= ~mark;
 424         }
 425         if (!dense)
 426                 return give_context(sline, cnt, num_parent);
 427
 428         /* Look at each hunk, and if we have changes from only one
 429          * parent, or the changes are the same from all but one
 430          * parent, mark that uninteresting.
 431          */
 432         i = 0;
 433         while (i < cnt) {
 434                 unsigned long j, hunk_begin, hunk_end;
 435                 unsigned long same_diff;
 436                 while (i < cnt && !(sline[i].flag & mark))
 437                         i++;
 438                 if (cnt <= i)
 439                         break; /* No more interesting hunks */
 440                 hunk_begin = i;
 441                 for (j = i + 1; j < cnt; j++) {
 442                         if (!(sline[j].flag & mark)) {
 443                                 /* Look beyond the end to see if there
 444                                  * is an interesting line after this
 445                                  * hunk within context span.
 446                                  */
 447                                 unsigned long la; /* lookahead */
 448                                 int contin = 0;
 449                                 la = adjust_hunk_tail(sline, all_mask,
 450                                                      hunk_begin, j);
 451                                 la = (la + context < cnt) ?
 452                                         (la + context) : cnt;
 453                                 while (j <= --la) {
 454                                         if (sline[la].flag & mark) {
 455                                                 contin = 1;
 456                                                 break;
 457                                         }
 458                                 }
 459                                 if (!contin)
 460                                         break;
 461                                 j = la;
 462                         }
 463                 }
 464                 hunk_end = j;
 465
 466                 /* [i..hunk_end) are interesting.  Now is it really
 467                  * interesting?  We check if there are only two versions
 468                  * and the result matches one of them.  That is, we look
 469                  * at:
 470                  *   (+) line, which records lines added to which parents;
 471                  *       this line appears in the result.
 472                  *   (-) line, which records from what parents the line
 473                  *       was removed; this line does not appear in the result.
 474                  * then check the set of parents the result has difference
 475                  * from, from all lines.  If there are lines that has
 476                  * different set of parents that the result has differences
 477                  * from, that means we have more than two versions.
 478                  *
 479                  * Even when we have only two versions, if the result does
 480                  * not match any of the parents, the it should be considered
 481                  * interesting.  In such a case, we would have all '+' line.
 482                  * After passing the above "two versions" test, that would
 483                  * appear as "the same set of parents" to be "all parents".
 484                  */
 485                 same_diff = 0;
 486                 has_interesting = 0;
 487                 for (j = i; j < hunk_end && !has_interesting; j++) {
 488                         unsigned long this_diff = sline[j].flag & all_mask;
 489                         struct lline *ll = sline[j].lost_head;
 490                         if (this_diff) {
 491                                 /* This has some changes.  Is it the
 492                                  * same as others?
 493                                  */
 494                                 if (!same_diff)
 495                                         same_diff = this_diff;
 496                                 else if (same_diff != this_diff) {
 497                                         has_interesting = 1;
 498                                         break;
 499                                 }
 500                         }
 501                         while (ll && !has_interesting) {
 502                                 /* Lost this line from these parents;
 503                                  * who are they?  Are they the same?
 504                                  */
 505                                 this_diff = ll->parent_map;
 506                                 if (!same_diff)
 507                                         same_diff = this_diff;
 508                                 else if (same_diff != this_diff) {
 509                                         has_interesting = 1;
 510                                 }
 511                                 ll = ll->next;
 512                         }
 513                 }
 514
 515                 if (!has_interesting && same_diff != all_mask) {
 516                         /* This hunk is not that interesting after all */
 517                         for (j = hunk_begin; j < hunk_end; j++)
 518                                 sline[j].flag &= ~mark;
 519                 }
 520                 i = hunk_end;
 521         }
 522
 523         has_interesting = give_context(sline, cnt, num_parent);
 524         return has_interesting;
 525 }
 526
 527 static void show_parent_lno(struct sline *sline, unsigned long l0, unsigned long l1, unsigned long cnt, int n)
 528 {
 529         l0 = sline[l0].p_lno[n];
 530         l1 = sline[l1].p_lno[n];
 531         printf(" -%lu,%lu", l0, l1-l0);
 532 }
 533
 534 static void dump_sline(struct sline *sline, unsigned long cnt, int num_parent)
 535 {
 536         unsigned long mark = (1UL<<num_parent);
 537         int i;
 538         unsigned long lno = 0;
 539
 540         while (1) {
 541                 struct sline *sl = &sline[lno];
 542                 int hunk_end;
 543                 while (lno < cnt && !(sline[lno].flag & mark))
 544                         lno++;
 545                 if (cnt <= lno)
 546                         break;
 547                 for (hunk_end = lno + 1; hunk_end < cnt; hunk_end++)
 548                         if (!(sline[hunk_end].flag & mark))
 549                                 break;
 550                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 551                 for (i = 0; i < num_parent; i++)
 552                         show_parent_lno(sline, lno, hunk_end, cnt, i);
 553                 printf(" +%lu,%lu ", lno+1, hunk_end-lno);
 554                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 555                 putchar('\n');
 556                 while (lno < hunk_end) {
 557                         struct lline *ll;
 558                         int j;
 559                         unsigned long p_mask;
 560                         sl = &sline[lno++];
 561                         ll = sl->lost_head;
 562                         while (ll) {
 563                                 for (j = 0; j < num_parent; j++) {
 564                                         if (ll->parent_map & (1UL<<j))
 565                                                 putchar('-');
 566                                         else
 567                                                 putchar(' ');
 568                                 }
 569                                 puts(ll->line);
 570                                 ll = ll->next;
 571                         }
 572                         p_mask = 1;
 573                         for (j = 0; j < num_parent; j++) {
 574                                 if (p_mask & sl->flag)
 575                                         putchar('+');
 576                                 else
 577                                         putchar(' ');
 578                                 p_mask <<= 1;
 579                         }
 580                         printf("%.*s\n", sl->len, sl->bol);
 581                 }
 582         }
 583 }
 584
 585 static void reuse_combine_diff(struct sline *sline, unsigned long cnt,
 586                                int i, int j)
 587 {
 588         /* We have already examined parent j and we know parent i
 589          * and parent j are the same, so reuse the combined result
 590          * of parent j for parent i.
 591          */
 592         unsigned long lno, imask, jmask;
 593         imask = (1UL<<i);
 594         jmask = (1UL<<j);
 595
 596         for (lno = 0; lno < cnt; lno++) {
 597                 struct lline *ll = sline->lost_head;
 598                 sline->p_lno[i] = sline->p_lno[j];
 599                 while (ll) {
 600                         if (ll->parent_map & jmask)
 601                                 ll->parent_map |= imask;
 602                         ll = ll->next;
 603                 }
 604                 if (sline->flag & jmask)
 605                         sline->flag |= imask;
 606                 sline++;
 607         }
 608 }
 609
 610 int show_combined_diff(struct combine_diff_path *elem, int num_parent,
 611                        int dense, const char *header)
 612 {
 613         unsigned long size, cnt, lno;
 614         char *result, *cp, *ep;
 615         struct sline *sline; /* survived lines */
 616         int i, show_hunks, shown_header = 0;
 617         char ourtmp_buf[TMPPATHLEN];
 618         char *ourtmp = ourtmp_buf;
 619
 620         /* Read the result of merge first */
 621         if (memcmp(elem->sha1, null_sha1, 20)) {
 622                 result = grab_blob(elem->sha1, &size);
 623                 write_to_temp_file(ourtmp, result, size);
 624         }
 625         else {
 626                 /* Used by diff-tree to read from the working tree */
 627                 struct stat st;
 628                 int fd;
 629                 ourtmp = elem->path;
 630                 if (0 <= (fd = open(ourtmp, O_RDONLY)) &&
 631                     !fstat(fd, &st)) {
 632                         int len = st.st_size;
 633                         int cnt = 0;
 634
 635                         size = len;
 636                         result = xmalloc(len + 1);
 637                         while (cnt < len) {
 638                                 int done = xread(fd, result+cnt, len-cnt);
 639                                 if (done == 0)
 640                                         break;
 641                                 if (done < 0)
 642                                         die("read error '%s'", ourtmp);
 643                                 cnt += done;
 644                         }
 645                         result[len] = 0;
 646                 }
 647                 else {
 648                         /* deleted file */
 649                         size = 0;
 650                         result = xmalloc(1);
 651                         result[0] = 0;
 652                         ourtmp = "/dev/null";
 653                 }
 654                 if (0 <= fd)
 655                         close(fd);
 656         }
 657
 658         for (cnt = 0, cp = result; cp - result < size; cp++) {
 659                 if (*cp == '\n')
 660                         cnt++;
 661         }
 662         if (result[size-1] != '\n')
 663                 cnt++; /* incomplete line */
 664
 665         sline = xcalloc(cnt+1, sizeof(*sline));
 666         ep = result;
 667         sline[0].bol = result;
 668         for (lno = 0, cp = result; cp - result < size; cp++) {
 669                 if (*cp == '\n') {
 670                         sline[lno].lost_tail = &sline[lno].lost_head;
 671                         sline[lno].len = cp - sline[lno].bol;
 672                         sline[lno].flag = 0;
 673                         lno++;
 674                         if (lno < cnt)
 675                                 sline[lno].bol = cp + 1;
 676                 }
 677         }
 678         if (result[size-1] != '\n') {
 679                 sline[cnt-1].lost_tail = &sline[cnt-1].lost_head;
 680                 sline[cnt-1].len = size - (sline[cnt-1].bol - result);
 681                 sline[cnt-1].flag = 0;
 682         }
 683
 684         sline[0].p_lno = xcalloc((cnt+1) * num_parent, sizeof(unsigned long));
 685         for (lno = 0; lno < cnt; lno++)
 686                 sline[lno+1].p_lno = sline[lno].p_lno + num_parent;
 687
 688         for (i = 0; i < num_parent; i++) {
 689                 int j;
 690                 for (j = 0; j < i; j++) {
 691                         if (!memcmp(elem->parent_sha1[i],
 692                                     elem->parent_sha1[j], 20)) {
 693                                 reuse_combine_diff(sline, cnt, i, j);
 694                                 break;
 695                         }
 696                 }
 697                 if (i <= j)
 698                         combine_diff(elem->parent_sha1[i], ourtmp, sline,
 699                                      cnt, i, num_parent);
 700         }
 701
 702         show_hunks = make_hunks(sline, cnt, num_parent, dense);
 703
 704         if (show_hunks) {
 705                 const char *abb;
 706                 char null_abb[DEFAULT_ABBREV + 1];
 707
 708                 memset(null_abb, '0', DEFAULT_ABBREV);
 709                 null_abb[DEFAULT_ABBREV] = 0;
 710                 if (header) {
 711                         shown_header++;
 712                         puts(header);
 713                 }
 714                 printf("diff --%s ", dense ? "cc" : "combined");
 715                 if (quote_c_style(elem->path, NULL, NULL, 0))
 716                         quote_c_style(elem->path, NULL, stdout, 0);
 717                 else
 718                         printf("%s", elem->path);
 719                 putchar('\n');
 720                 printf("index ");
 721                 for (i = 0; i < num_parent; i++) {
 722                         if (memcmp(elem->parent_sha1[i], null_sha1, 20))
 723                                 abb = find_unique_abbrev(elem->parent_sha1[i],
 724                                                          DEFAULT_ABBREV);
 725                         else
 726                                 abb = null_abb;
 727                         printf("%s%s", i ? "," : "", abb);
 728                 }
 729                 if (memcmp(elem->sha1, null_sha1, 20))
 730                         abb = find_unique_abbrev(elem->sha1, DEFAULT_ABBREV);
 731                 else
 732                         abb = null_abb;
 733                 printf("..%s\n", abb);
 734                 dump_sline(sline, cnt, num_parent);
 735         }
 736         if (ourtmp == ourtmp_buf)
 737                 unlink(ourtmp);
 738         free(result);
 739
 740         for (i = 0; i < cnt; i++) {
 741                 if (sline[i].lost_head) {
 742                         struct lline *ll = sline[i].lost_head;
 743                         while (ll) {
 744                                 struct lline *tmp = ll;
 745                                 ll = ll->next;
 746                                 free(tmp);
 747                         }
 748                 }
 749         }
 750         free(sline[0].p_lno);
 751         free(sline);
 752         return shown_header;
 753 }
 754
 755 int diff_tree_combined_merge(const unsigned char *sha1,
 756                              const char *header, int dense)
 757 {
 758         struct commit *commit = lookup_commit(sha1);
 759         struct diff_options diffopts;
 760         struct commit_list *parents;
 761         struct combine_diff_path *p, *paths = NULL;
 762         int num_parent, i, num_paths;
 763
 764         diff_setup(&diffopts);
 765         diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
 766         diffopts.recursive = 1;
 767
 768         /* count parents */
 769         for (parents = commit->parents, num_parent = 0;
 770              parents;
 771              parents = parents->next, num_parent++)
 772                 ; /* nothing */
 773
 774         /* find set of paths that everybody touches */
 775         for (parents = commit->parents, i = 0;
 776              parents;
 777              parents = parents->next, i++) {
 778                 struct commit *parent = parents->item;
 779                 diff_tree_sha1(parent->object.sha1, commit->object.sha1, "",
 780                                &diffopts);
 781                 paths = intersect_paths(paths, i, num_parent);
 782                 diff_flush(&diffopts);
 783         }
 784
 785         /* find out surviving paths */
 786         for (num_paths = 0, p = paths; p; p = p->next) {
 787                 if (p->len)
 788                         num_paths++;
 789         }
 790         if (num_paths) {
 791                 for (p = paths; p; p = p->next) {
 792                         if (!p->len)
 793                                 continue;
 794                         if (show_combined_diff(p, num_parent, dense, header))
 795                                 header = NULL;
 796                 }
 797         }
 798
 799         /* Clean things up */
 800         while (paths) {
 801                 struct combine_diff_path *tmp = paths;
 802                 paths = paths->next;
 803                 free(tmp);
 804         }
 805         return 0;
 806 }