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