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
   8 static int uninteresting(struct diff_filepair *p)
   9 {
  10         if (diff_unmodified_pair(p))
  11                 return 1;
  12         return 0;
  13 }
  14
  15 static struct combine_diff_path *intersect_paths(struct combine_diff_path *curr, int n, int num_parent)
  16 {
  17         struct diff_queue_struct *q = &diff_queued_diff;
  18         struct combine_diff_path *p;
  19         int i;
  20
  21         if (!n) {
  22                 struct combine_diff_path *list = NULL, **tail = &list;
  23                 for (i = 0; i < q->nr; i++) {
  24                         int len;
  25                         const char *path;
  26                         if (uninteresting(q->queue[i]))
  27                                 continue;
  28                         path = q->queue[i]->two->path;
  29                         len = strlen(path);
  30                         p = xmalloc(combine_diff_path_size(num_parent, len));
  31                         p->path = (char*) &(p->parent[num_parent]);
  32                         memcpy(p->path, path, len);
  33                         p->path[len] = 0;
  34                         p->len = len;
  35                         p->next = NULL;
  36                         memset(p->parent, 0,
  37                                sizeof(p->parent[0]) * num_parent);
  38
  39                         memcpy(p->sha1, q->queue[i]->two->sha1, 20);
  40                         p->mode = q->queue[i]->two->mode;
  41                         memcpy(p->parent[n].sha1, q->queue[i]->one->sha1, 20);
  42                         p->parent[n].mode = q->queue[i]->one->mode;
  43                         p->parent[n].status = q->queue[i]->status;
  44                         *tail = p;
  45                         tail = &p->next;
  46                 }
  47                 return list;
  48         }
  49
  50         for (p = curr; p; p = p->next) {
  51                 int found = 0;
  52                 if (!p->len)
  53                         continue;
  54                 for (i = 0; i < q->nr; i++) {
  55                         const char *path;
  56                         int len;
  57
  58                         if (uninteresting(q->queue[i]))
  59                                 continue;
  60                         path = q->queue[i]->two->path;
  61                         len = strlen(path);
  62                         if (len == p->len && !memcmp(path, p->path, len)) {
  63                                 found = 1;
  64                                 memcpy(p->parent[n].sha1,
  65                                        q->queue[i]->one->sha1, 20);
  66                                 p->parent[n].mode = q->queue[i]->one->mode;
  67                                 p->parent[n].status = q->queue[i]->status;
  68                                 break;
  69                         }
  70                 }
  71                 if (!found)
  72                         p->len = 0;
  73         }
  74         return curr;
  75 }
  76
  77 /* Lines lost from parent */
  78 struct lline {
  79         struct lline *next;
  80         int len;
  81         unsigned long parent_map;
  82         char line[FLEX_ARRAY];
  83 };
  84
  85 /* Lines surviving in the merge result */
  86 struct sline {
  87         struct lline *lost_head, **lost_tail;
  88         char *bol;
  89         int len;
  90         /* bit 0 up to (N-1) are on if the parent has this line (i.e.
  91          * we did not change it).
  92          * bit N is used for "interesting" lines, including context.
  93          */
  94         unsigned long flag;
  95         unsigned long *p_lno;
  96 };
  97
  98 static char *grab_blob(const unsigned char *sha1, unsigned long *size)
  99 {
 100         char *blob;
 101         char type[20];
 102         if (!memcmp(sha1, null_sha1, 20)) {
 103                 /* deleted blob */
 104                 *size = 0;
 105                 return xcalloc(1, 1);
 106         }
 107         blob = read_sha1_file(sha1, type, size);
 108         if (strcmp(type, blob_type))
 109                 die("object '%s' is not a blob!", sha1_to_hex(sha1));
 110         return blob;
 111 }
 112
 113 #define TMPPATHLEN 50
 114 #define MAXLINELEN 10240
 115
 116 static void write_to_temp_file(char *tmpfile, void *blob, unsigned long size)
 117 {
 118         int fd = git_mkstemp(tmpfile, TMPPATHLEN, ".diff_XXXXXX");
 119         if (fd < 0)
 120                 die("unable to create temp-file");
 121         if (write(fd, blob, size) != size)
 122                 die("unable to write temp-file");
 123         close(fd);
 124 }
 125
 126 static void write_temp_blob(char *tmpfile, const unsigned char *sha1)
 127 {
 128         unsigned long size;
 129         void *blob;
 130         blob = grab_blob(sha1, &size);
 131         write_to_temp_file(tmpfile, blob, size);
 132         free(blob);
 133 }
 134
 135 static int parse_num(char **cp_p, unsigned int *num_p)
 136 {
 137         char *cp = *cp_p;
 138         unsigned int num = 0;
 139         int read_some;
 140
 141         while ('0' <= *cp && *cp <= '9')
 142                 num = num * 10 + *cp++ - '0';
 143         if (!(read_some = cp - *cp_p))
 144                 return -1;
 145         *cp_p = cp;
 146         *num_p = num;
 147         return 0;
 148 }
 149
 150 static int parse_hunk_header(char *line, int len,
 151                              unsigned int *ob, unsigned int *on,
 152                              unsigned int *nb, unsigned int *nn)
 153 {
 154         char *cp;
 155         cp = line + 4;
 156         if (parse_num(&cp, ob)) {
 157         bad_line:
 158                 return error("malformed diff output: %s", line);
 159         }
 160         if (*cp == ',') {
 161                 cp++;
 162                 if (parse_num(&cp, on))
 163                         goto bad_line;
 164         }
 165         else
 166                 *on = 1;
 167         if (*cp++ != ' ' || *cp++ != '+')
 168                 goto bad_line;
 169         if (parse_num(&cp, nb))
 170                 goto bad_line;
 171         if (*cp == ',') {
 172                 cp++;
 173                 if (parse_num(&cp, nn))
 174                         goto bad_line;
 175         }
 176         else
 177                 *nn = 1;
 178         return -!!memcmp(cp, " @@", 3);
 179 }
 180
 181 static void append_lost(struct sline *sline, int n, const char *line)
 182 {
 183         struct lline *lline;
 184         int len = strlen(line);
 185         unsigned long this_mask = (1UL<<n);
 186         if (line[len-1] == '\n')
 187                 len--;
 188
 189         /* Check to see if we can squash things */
 190         if (sline->lost_head) {
 191                 struct lline *last_one = NULL;
 192                 /* We cannot squash it with earlier one */
 193                 for (lline = sline->lost_head;
 194                      lline;
 195                      lline = lline->next)
 196                         if (lline->parent_map & this_mask)
 197                                 last_one = lline;
 198                 lline = last_one ? last_one->next : sline->lost_head;
 199                 while (lline) {
 200                         if (lline->len == len &&
 201                             !memcmp(lline->line, line, len)) {
 202                                 lline->parent_map |= this_mask;
 203                                 return;
 204                         }
 205                         lline = lline->next;
 206                 }
 207         }
 208
 209         lline = xmalloc(sizeof(*lline) + len + 1);
 210         lline->len = len;
 211         lline->next = NULL;
 212         lline->parent_map = this_mask;
 213         memcpy(lline->line, line, len);
 214         lline->line[len] = 0;
 215         *sline->lost_tail = lline;
 216         sline->lost_tail = &lline->next;
 217 }
 218
 219 static void combine_diff(const unsigned char *parent, const char *ourtmp,
 220                          struct sline *sline, int cnt, int n, int num_parent)
 221 {
 222         FILE *in;
 223         char parent_tmp[TMPPATHLEN];
 224         char cmd[TMPPATHLEN * 2 + 1024];
 225         char line[MAXLINELEN];
 226         unsigned int lno, ob, on, nb, nn, p_lno;
 227         unsigned long nmask = (1UL << n);
 228         struct sline *lost_bucket = NULL;
 229
 230         if (!cnt)
 231                 return; /* result deleted */
 232
 233         write_temp_blob(parent_tmp, parent);
 234         sprintf(cmd, "diff --unified=0 -La/x -Lb/x '%s' '%s'",
 235                 parent_tmp, ourtmp);
 236         in = popen(cmd, "r");
 237         if (!in)
 238                 die("cannot spawn %s", cmd);
 239
 240         lno = 1;
 241         while (fgets(line, sizeof(line), in) != NULL) {
 242                 int len = strlen(line);
 243                 if (5 < len && !memcmp("@@ -", line, 4)) {
 244                         if (parse_hunk_header(line, len,
 245                                               &ob, &on, &nb, &nn))
 246                                 break;
 247                         lno = nb;
 248                         if (!nb)
 249                                 /* @@ -1,2 +0,0 @@ to remove the
 250                                  * first two lines...
 251                                  */
 252                                 nb = 1;
 253                         if (nn == 0)
 254                                 /* @@ -X,Y +N,0 @@ removed Y lines
 255                                  * that would have come *after* line N
 256                                  * in the result.  Our lost buckets hang
 257                                  * to the line after the removed lines,
 258                                  */
 259                                 lost_bucket = &sline[nb];
 260                         else
 261                                 lost_bucket = &sline[nb-1];
 262                         if (!sline[nb-1].p_lno)
 263                                 sline[nb-1].p_lno =
 264                                         xcalloc(num_parent,
 265                                                 sizeof(unsigned long));
 266                         sline[nb-1].p_lno[n] = ob;
 267                         continue;
 268                 }
 269                 if (!lost_bucket)
 270                         continue; /* not in any hunk yet */
 271                 switch (line[0]) {
 272                 case '-':
 273                         append_lost(lost_bucket, n, line+1);
 274                         break;
 275                 case '+':
 276                         sline[lno-1].flag |= nmask;
 277                         lno++;
 278                         break;
 279                 }
 280         }
 281         fclose(in);
 282         unlink(parent_tmp);
 283
 284         /* Assign line numbers for this parent.
 285          *
 286          * sline[lno].p_lno[n] records the first line number
 287          * (counting from 1) for parent N if the final hunk display
 288          * started by showing sline[lno] (possibly showing the lost
 289          * lines attached to it first).
 290          */
 291         for (lno = 0,  p_lno = 1; lno < cnt; lno++) {
 292                 struct lline *ll;
 293                 sline[lno].p_lno[n] = p_lno;
 294
 295                 /* How many lines would this sline advance the p_lno? */
 296                 ll = sline[lno].lost_head;
 297                 while (ll) {
 298                         if (ll->parent_map & nmask)
 299                                 p_lno++; /* '-' means parent had it */
 300                         ll = ll->next;
 301                 }
 302                 if (!(sline[lno].flag & nmask))
 303                         p_lno++; /* no '+' means parent had it */
 304         }
 305         sline[lno].p_lno[n] = p_lno; /* trailer */
 306 }
 307
 308 static unsigned long context = 3;
 309 static char combine_marker = '@';
 310
 311 static int interesting(struct sline *sline, unsigned long all_mask)
 312 {
 313         /* If some parents lost lines here, or if we have added to
 314          * some parent, it is interesting.
 315          */
 316         return ((sline->flag & all_mask) || sline->lost_head);
 317 }
 318
 319 static unsigned long adjust_hunk_tail(struct sline *sline,
 320                                       unsigned long all_mask,
 321                                       unsigned long hunk_begin,
 322                                       unsigned long i)
 323 {
 324         /* i points at the first uninteresting line.  If the last line
 325          * of the hunk was interesting only because it has some
 326          * deletion, then it is not all that interesting for the
 327          * purpose of giving trailing context lines.  This is because
 328          * we output '-' line and then unmodified sline[i-1] itself in
 329          * that case which gives us one extra context line.
 330          */
 331         if ((hunk_begin + 1 <= i) && !(sline[i-1].flag & all_mask))
 332                 i--;
 333         return i;
 334 }
 335
 336 static unsigned long find_next(struct sline *sline,
 337                                unsigned long mark,
 338                                unsigned long i,
 339                                unsigned long cnt,
 340                                int uninteresting)
 341 {
 342         /* We have examined up to i-1 and are about to look at i.
 343          * Find next interesting or uninteresting line.  Here,
 344          * "interesting" does not mean interesting(), but marked by
 345          * the give_context() function below (i.e. it includes context
 346          * lines that are not interesting to interesting() function
 347          * that are surrounded by interesting() ones.
 348          */
 349         while (i < cnt)
 350                 if (uninteresting
 351                     ? !(sline[i].flag & mark)
 352                     : (sline[i].flag & mark))
 353                         return i;
 354                 else
 355                         i++;
 356         return cnt;
 357 }
 358
 359 static int give_context(struct sline *sline, unsigned long cnt, int num_parent)
 360 {
 361         unsigned long all_mask = (1UL<<num_parent) - 1;
 362         unsigned long mark = (1UL<<num_parent);
 363         unsigned long i;
 364
 365         /* Two groups of interesting lines may have a short gap of
 366          * unintersting lines.  Connect such groups to give them a
 367          * bit of context.
 368          *
 369          * We first start from what the interesting() function says,
 370          * and mark them with "mark", and paint context lines with the
 371          * mark.  So interesting() would still say false for such context
 372          * lines but they are treated as "interesting" in the end.
 373          */
 374         i = find_next(sline, mark, 0, cnt, 0);
 375         if (cnt <= i)
 376                 return 0;
 377
 378         while (i < cnt) {
 379                 unsigned long j = (context < i) ? (i - context) : 0;
 380                 unsigned long k;
 381
 382                 /* Paint a few lines before the first interesting line. */
 383                 while (j < i)
 384                         sline[j++].flag |= mark;
 385
 386         again:
 387                 /* we know up to i is to be included.  where does the
 388                  * next uninteresting one start?
 389                  */
 390                 j = find_next(sline, mark, i, cnt, 1);
 391                 if (cnt <= j)
 392                         break; /* the rest are all interesting */
 393
 394                 /* lookahead context lines */
 395                 k = find_next(sline, mark, j, cnt, 0);
 396                 j = adjust_hunk_tail(sline, all_mask, i, j);
 397
 398                 if (k < j + context) {
 399                         /* k is interesting and [j,k) are not, but
 400                          * paint them interesting because the gap is small.
 401                          */
 402                         while (j < k)
 403                                 sline[j++].flag |= mark;
 404                         i = k;
 405                         goto again;
 406                 }
 407
 408                 /* j is the first uninteresting line and there is
 409                  * no overlap beyond it within context lines.  Paint
 410                  * the trailing edge a bit.
 411                  */
 412                 i = k;
 413                 k = (j + context < cnt) ? j + context : cnt;
 414                 while (j < k)
 415                         sline[j++].flag |= mark;
 416         }
 417         return 1;
 418 }
 419
 420 static int make_hunks(struct sline *sline, unsigned long cnt,
 421                        int num_parent, int dense)
 422 {
 423         unsigned long all_mask = (1UL<<num_parent) - 1;
 424         unsigned long mark = (1UL<<num_parent);
 425         unsigned long i;
 426         int has_interesting = 0;
 427
 428         for (i = 0; i < cnt; i++) {
 429                 if (interesting(&sline[i], all_mask))
 430                         sline[i].flag |= mark;
 431                 else
 432                         sline[i].flag &= ~mark;
 433         }
 434         if (!dense)
 435                 return give_context(sline, cnt, num_parent);
 436
 437         /* Look at each hunk, and if we have changes from only one
 438          * parent, or the changes are the same from all but one
 439          * parent, mark that uninteresting.
 440          */
 441         i = 0;
 442         while (i < cnt) {
 443                 unsigned long j, hunk_begin, hunk_end;
 444                 unsigned long same_diff;
 445                 while (i < cnt && !(sline[i].flag & mark))
 446                         i++;
 447                 if (cnt <= i)
 448                         break; /* No more interesting hunks */
 449                 hunk_begin = i;
 450                 for (j = i + 1; j < cnt; j++) {
 451                         if (!(sline[j].flag & mark)) {
 452                                 /* Look beyond the end to see if there
 453                                  * is an interesting line after this
 454                                  * hunk within context span.
 455                                  */
 456                                 unsigned long la; /* lookahead */
 457                                 int contin = 0;
 458                                 la = adjust_hunk_tail(sline, all_mask,
 459                                                      hunk_begin, j);
 460                                 la = (la + context < cnt) ?
 461                                         (la + context) : cnt;
 462                                 while (j <= --la) {
 463                                         if (sline[la].flag & mark) {
 464                                                 contin = 1;
 465                                                 break;
 466                                         }
 467                                 }
 468                                 if (!contin)
 469                                         break;
 470                                 j = la;
 471                         }
 472                 }
 473                 hunk_end = j;
 474
 475                 /* [i..hunk_end) are interesting.  Now is it really
 476                  * interesting?  We check if there are only two versions
 477                  * and the result matches one of them.  That is, we look
 478                  * at:
 479                  *   (+) line, which records lines added to which parents;
 480                  *       this line appears in the result.
 481                  *   (-) line, which records from what parents the line
 482                  *       was removed; this line does not appear in the result.
 483                  * then check the set of parents the result has difference
 484                  * from, from all lines.  If there are lines that has
 485                  * different set of parents that the result has differences
 486                  * from, that means we have more than two versions.
 487                  *
 488                  * Even when we have only two versions, if the result does
 489                  * not match any of the parents, the it should be considered
 490                  * interesting.  In such a case, we would have all '+' line.
 491                  * After passing the above "two versions" test, that would
 492                  * appear as "the same set of parents" to be "all parents".
 493                  */
 494                 same_diff = 0;
 495                 has_interesting = 0;
 496                 for (j = i; j < hunk_end && !has_interesting; j++) {
 497                         unsigned long this_diff = sline[j].flag & all_mask;
 498                         struct lline *ll = sline[j].lost_head;
 499                         if (this_diff) {
 500                                 /* This has some changes.  Is it the
 501                                  * same as others?
 502                                  */
 503                                 if (!same_diff)
 504                                         same_diff = this_diff;
 505                                 else if (same_diff != this_diff) {
 506                                         has_interesting = 1;
 507                                         break;
 508                                 }
 509                         }
 510                         while (ll && !has_interesting) {
 511                                 /* Lost this line from these parents;
 512                                  * who are they?  Are they the same?
 513                                  */
 514                                 this_diff = ll->parent_map;
 515                                 if (!same_diff)
 516                                         same_diff = this_diff;
 517                                 else if (same_diff != this_diff) {
 518                                         has_interesting = 1;
 519                                 }
 520                                 ll = ll->next;
 521                         }
 522                 }
 523
 524                 if (!has_interesting && same_diff != all_mask) {
 525                         /* This hunk is not that interesting after all */
 526                         for (j = hunk_begin; j < hunk_end; j++)
 527                                 sline[j].flag &= ~mark;
 528                 }
 529                 i = hunk_end;
 530         }
 531
 532         has_interesting = give_context(sline, cnt, num_parent);
 533         return has_interesting;
 534 }
 535
 536 static void show_parent_lno(struct sline *sline, unsigned long l0, unsigned long l1, unsigned long cnt, int n)
 537 {
 538         l0 = sline[l0].p_lno[n];
 539         l1 = sline[l1].p_lno[n];
 540         printf(" -%lu,%lu", l0, l1-l0);
 541 }
 542
 543 static void dump_sline(struct sline *sline, unsigned long cnt, int num_parent)
 544 {
 545         unsigned long mark = (1UL<<num_parent);
 546         int i;
 547         unsigned long lno = 0;
 548
 549         if (!cnt)
 550                 return; /* result deleted */
 551
 552         while (1) {
 553                 struct sline *sl = &sline[lno];
 554                 int hunk_end;
 555                 while (lno < cnt && !(sline[lno].flag & mark))
 556                         lno++;
 557                 if (cnt <= lno)
 558                         break;
 559                 for (hunk_end = lno + 1; hunk_end < cnt; hunk_end++)
 560                         if (!(sline[hunk_end].flag & mark))
 561                                 break;
 562                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 563                 for (i = 0; i < num_parent; i++)
 564                         show_parent_lno(sline, lno, hunk_end, cnt, i);
 565                 printf(" +%lu,%lu ", lno+1, hunk_end-lno);
 566                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 567                 putchar('\n');
 568                 while (lno < hunk_end) {
 569                         struct lline *ll;
 570                         int j;
 571                         unsigned long p_mask;
 572                         sl = &sline[lno++];
 573                         ll = sl->lost_head;
 574                         while (ll) {
 575                                 for (j = 0; j < num_parent; j++) {
 576                                         if (ll->parent_map & (1UL<<j))
 577                                                 putchar('-');
 578                                         else
 579                                                 putchar(' ');
 580                                 }
 581                                 puts(ll->line);
 582                                 ll = ll->next;
 583                         }
 584                         p_mask = 1;
 585                         for (j = 0; j < num_parent; j++) {
 586                                 if (p_mask & sl->flag)
 587                                         putchar('+');
 588                                 else
 589                                         putchar(' ');
 590                                 p_mask <<= 1;
 591                         }
 592                         printf("%.*s\n", sl->len, sl->bol);
 593                 }
 594         }
 595 }
 596
 597 static void reuse_combine_diff(struct sline *sline, unsigned long cnt,
 598                                int i, int j)
 599 {
 600         /* We have already examined parent j and we know parent i
 601          * and parent j are the same, so reuse the combined result
 602          * of parent j for parent i.
 603          */
 604         unsigned long lno, imask, jmask;
 605         imask = (1UL<<i);
 606         jmask = (1UL<<j);
 607
 608         for (lno = 0; lno < cnt; lno++) {
 609                 struct lline *ll = sline->lost_head;
 610                 sline->p_lno[i] = sline->p_lno[j];
 611                 while (ll) {
 612                         if (ll->parent_map & jmask)
 613                                 ll->parent_map |= imask;
 614                         ll = ll->next;
 615                 }
 616                 if (sline->flag & jmask)
 617                         sline->flag |= imask;
 618                 sline++;
 619         }
 620         /* the overall size of the file (sline[cnt]) */
 621         sline->p_lno[i] = sline->p_lno[j];
 622 }
 623
 624 static int show_patch_diff(struct combine_diff_path *elem, int num_parent,
 625                            int dense, const char *header,
 626                            struct diff_options *opt)
 627 {
 628         unsigned long size, cnt, lno;
 629         char *result, *cp, *ep;
 630         struct sline *sline; /* survived lines */
 631         int mode_differs = 0;
 632         int i, show_hunks, shown_header = 0;
 633         char ourtmp_buf[TMPPATHLEN];
 634         char *ourtmp = ourtmp_buf;
 635         int working_tree_file = !memcmp(elem->sha1, null_sha1, 20);
 636         int abbrev = opt->full_index ? 40 : DEFAULT_ABBREV;
 637
 638         /* Read the result of merge first */
 639         if (!working_tree_file) {
 640                 result = grab_blob(elem->sha1, &size);
 641                 write_to_temp_file(ourtmp, result, size);
 642         }
 643         else {
 644                 /* Used by diff-tree to read from the working tree */
 645                 struct stat st;
 646                 int fd;
 647                 ourtmp = elem->path;
 648                 if (0 <= (fd = open(ourtmp, O_RDONLY)) &&
 649                     !fstat(fd, &st)) {
 650                         int len = st.st_size;
 651                         int cnt = 0;
 652
 653                         elem->mode = canon_mode(st.st_mode);
 654                         size = len;
 655                         result = xmalloc(len + 1);
 656                         while (cnt < len) {
 657                                 int done = xread(fd, result+cnt, len-cnt);
 658                                 if (done == 0)
 659                                         break;
 660                                 if (done < 0)
 661                                         die("read error '%s'", ourtmp);
 662                                 cnt += done;
 663                         }
 664                         result[len] = 0;
 665                 }
 666                 else {
 667                         /* deleted file */
 668                         size = 0;
 669                         elem->mode = 0;
 670                         result = xmalloc(1);
 671                         result[0] = 0;
 672                         ourtmp = "/dev/null";
 673                 }
 674                 if (0 <= fd)
 675                         close(fd);
 676         }
 677
 678         for (cnt = 0, cp = result; cp - result < size; cp++) {
 679                 if (*cp == '\n')
 680                         cnt++;
 681         }
 682         if (size && result[size-1] != '\n')
 683                 cnt++; /* incomplete line */
 684
 685         sline = xcalloc(cnt+1, sizeof(*sline));
 686         ep = result;
 687         sline[0].bol = result;
 688         for (lno = 0; lno <= cnt; lno++) {
 689                 sline[lno].lost_tail = &sline[lno].lost_head;
 690                 sline[lno].flag = 0;
 691         }
 692         for (lno = 0, cp = result; cp - result < size; cp++) {
 693                 if (*cp == '\n') {
 694                         sline[lno].len = cp - sline[lno].bol;
 695                         lno++;
 696                         if (lno < cnt)
 697                                 sline[lno].bol = cp + 1;
 698                 }
 699         }
 700         if (size && result[size-1] != '\n')
 701                 sline[cnt-1].len = size - (sline[cnt-1].bol - result);
 702
 703         sline[0].p_lno = xcalloc((cnt+1) * num_parent, sizeof(unsigned long));
 704         for (lno = 0; lno < cnt; lno++)
 705                 sline[lno+1].p_lno = sline[lno].p_lno + num_parent;
 706
 707         for (i = 0; i < num_parent; i++) {
 708                 int j;
 709                 for (j = 0; j < i; j++) {
 710                         if (!memcmp(elem->parent[i].sha1,
 711                                     elem->parent[j].sha1, 20)) {
 712                                 reuse_combine_diff(sline, cnt, i, j);
 713                                 break;
 714                         }
 715                 }
 716                 if (i <= j)
 717                         combine_diff(elem->parent[i].sha1, ourtmp, sline,
 718                                      cnt, i, num_parent);
 719                 if (elem->parent[i].mode != elem->mode)
 720                         mode_differs = 1;
 721         }
 722
 723         show_hunks = make_hunks(sline, cnt, num_parent, dense);
 724
 725         if (show_hunks || mode_differs || working_tree_file) {
 726                 const char *abb;
 727
 728                 if (header) {
 729                         shown_header++;
 730                         printf("%s%c", header, opt->line_termination);
 731                 }
 732                 printf("diff --%s ", dense ? "cc" : "combined");
 733                 if (quote_c_style(elem->path, NULL, NULL, 0))
 734                         quote_c_style(elem->path, NULL, stdout, 0);
 735                 else
 736                         printf("%s", elem->path);
 737                 putchar('\n');
 738                 printf("index ");
 739                 for (i = 0; i < num_parent; i++) {
 740                         abb = find_unique_abbrev(elem->parent[i].sha1,
 741                                                  abbrev);
 742                         printf("%s%s", i ? "," : "", abb);
 743                 }
 744                 abb = find_unique_abbrev(elem->sha1, abbrev);
 745                 printf("..%s\n", abb);
 746
 747                 if (mode_differs) {
 748                         int added = !!elem->mode;
 749                         for (i = 0; added && i < num_parent; i++)
 750                                 if (elem->parent[i].status !=
 751                                     DIFF_STATUS_ADDED)
 752                                         added = 0;
 753                         if (added)
 754                                 printf("new file mode %06o", elem->mode);
 755                         else {
 756                                 if (!elem->mode)
 757                                         printf("deleted file ");
 758                                 printf("mode ");
 759                                 for (i = 0; i < num_parent; i++) {
 760                                         printf("%s%06o", i ? "," : "",
 761                                                elem->parent[i].mode);
 762                                 }
 763                                 if (elem->mode)
 764                                         printf("..%06o", elem->mode);
 765                         }
 766                         putchar('\n');
 767                 }
 768                 dump_sline(sline, cnt, num_parent);
 769         }
 770         if (ourtmp == ourtmp_buf)
 771                 unlink(ourtmp);
 772         free(result);
 773
 774         for (i = 0; i < cnt; i++) {
 775                 if (sline[i].lost_head) {
 776                         struct lline *ll = sline[i].lost_head;
 777                         while (ll) {
 778                                 struct lline *tmp = ll;
 779                                 ll = ll->next;
 780                                 free(tmp);
 781                         }
 782                 }
 783         }
 784         free(sline[0].p_lno);
 785         free(sline);
 786         return shown_header;
 787 }
 788
 789 #define COLONS "::::::::::::::::::::::::::::::::"
 790
 791 static void show_raw_diff(struct combine_diff_path *p, int num_parent, const char *header, struct diff_options *opt)
 792 {
 793         int i, offset, mod_type = 'A';
 794         const char *prefix;
 795         int line_termination, inter_name_termination;
 796
 797         line_termination = opt->line_termination;
 798         inter_name_termination = '\t';
 799         if (!line_termination)
 800                 inter_name_termination = 0;
 801
 802         if (header)
 803                 printf("%s%c", header, line_termination);
 804
 805         for (i = 0; i < num_parent; i++) {
 806                 if (p->parent[i].mode)
 807                         mod_type = 'M';
 808         }
 809         if (!p->mode)
 810                 mod_type = 'D';
 811
 812         if (opt->output_format == DIFF_FORMAT_RAW) {
 813                 offset = strlen(COLONS) - num_parent;
 814                 if (offset < 0)
 815                         offset = 0;
 816                 prefix = COLONS + offset;
 817
 818                 /* Show the modes */
 819                 for (i = 0; i < num_parent; i++) {
 820                         printf("%s%06o", prefix, p->parent[i].mode);
 821                         prefix = " ";
 822                 }
 823                 printf("%s%06o", prefix, p->mode);
 824
 825                 /* Show sha1's */
 826                 for (i = 0; i < num_parent; i++)
 827                         printf(" %s", diff_unique_abbrev(p->parent[i].sha1,
 828                                                          opt->abbrev));
 829                 printf(" %s ", diff_unique_abbrev(p->sha1, opt->abbrev));
 830         }
 831
 832         if (opt->output_format == DIFF_FORMAT_RAW ||
 833             opt->output_format == DIFF_FORMAT_NAME_STATUS) {
 834                 for (i = 0; i < num_parent; i++)
 835                         putchar(p->parent[i].status);
 836                 putchar(inter_name_termination);
 837         }
 838
 839         if (line_termination) {
 840                 if (quote_c_style(p->path, NULL, NULL, 0))
 841                         quote_c_style(p->path, NULL, stdout, 0);
 842                 else
 843                         printf("%s", p->path);
 844                 putchar(line_termination);
 845         }
 846         else {
 847                 printf("%s%c", p->path, line_termination);
 848         }
 849 }
 850
 851 int show_combined_diff(struct combine_diff_path *p,
 852                        int num_parent,
 853                        int dense,
 854                        const char *header,
 855                        struct diff_options *opt)
 856 {
 857         if (!p->len)
 858                 return 0;
 859         switch (opt->output_format) {
 860         case DIFF_FORMAT_RAW:
 861         case DIFF_FORMAT_NAME_STATUS:
 862         case DIFF_FORMAT_NAME:
 863                 show_raw_diff(p, num_parent, header, opt);
 864                 return 1;
 865
 866         default:
 867         case DIFF_FORMAT_PATCH:
 868                 return show_patch_diff(p, num_parent, dense, header, opt);
 869         }
 870 }
 871
 872 const char *diff_tree_combined_merge(const unsigned char *sha1,
 873                              const char *header, int dense,
 874                              struct diff_options *opt)
 875 {
 876         struct commit *commit = lookup_commit(sha1);
 877         struct diff_options diffopts;
 878         struct commit_list *parents;
 879         struct combine_diff_path *p, *paths = NULL;
 880         int num_parent, i, num_paths;
 881
 882         diffopts = *opt;
 883         diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
 884         diffopts.recursive = 1;
 885
 886         /* count parents */
 887         for (parents = commit->parents, num_parent = 0;
 888              parents;
 889              parents = parents->next, num_parent++)
 890                 ; /* nothing */
 891
 892         /* find set of paths that everybody touches */
 893         for (parents = commit->parents, i = 0;
 894              parents;
 895              parents = parents->next, i++) {
 896                 struct commit *parent = parents->item;
 897                 diff_tree_sha1(parent->object.sha1, commit->object.sha1, "",
 898                                &diffopts);
 899                 diffcore_std(&diffopts);
 900                 paths = intersect_paths(paths, i, num_parent);
 901                 diff_flush(&diffopts);
 902         }
 903
 904         /* find out surviving paths */
 905         for (num_paths = 0, p = paths; p; p = p->next) {
 906                 if (p->len)
 907                         num_paths++;
 908         }
 909         if (num_paths) {
 910                 for (p = paths; p; p = p->next) {
 911                         if (show_combined_diff(p, num_parent, dense,
 912                                                header, opt))
 913                                 header = NULL;
 914                 }
 915         }
 916
 917         /* Clean things up */
 918         while (paths) {
 919                 struct combine_diff_path *tmp = paths;
 920                 paths = paths->next;
 921                 free(tmp);
 922         }
 923         return header;
 924 }