combine-diff.c

   1 #include "cache.h"
   2 #include "commit.h"
   3 #include "blob.h"
   4 #include "diff.h"
   5 #include "diffcore.h"
   6 #include "quote.h"
   7 #include "xdiff-interface.h"
   8
   9 static int uninteresting(struct diff_filepair *p)
  10 {
  11         if (diff_unmodified_pair(p))
  12                 return 1;
  13         return 0;
  14 }
  15
  16 static struct combine_diff_path *intersect_paths(struct combine_diff_path *curr, int n, int num_parent)
  17 {
  18         struct diff_queue_struct *q = &diff_queued_diff;
  19         struct combine_diff_path *p;
  20         int i;
  21
  22         if (!n) {
  23                 struct combine_diff_path *list = NULL, **tail = &list;
  24                 for (i = 0; i < q->nr; i++) {
  25                         int len;
  26                         const char *path;
  27                         if (uninteresting(q->queue[i]))
  28                                 continue;
  29                         path = q->queue[i]->two->path;
  30                         len = strlen(path);
  31                         p = xmalloc(combine_diff_path_size(num_parent, len));
  32                         p->path = (char*) &(p->parent[num_parent]);
  33                         memcpy(p->path, path, len);
  34                         p->path[len] = 0;
  35                         p->len = len;
  36                         p->next = NULL;
  37                         memset(p->parent, 0,
  38                                sizeof(p->parent[0]) * num_parent);
  39
  40                         memcpy(p->sha1, q->queue[i]->two->sha1, 20);
  41                         p->mode = q->queue[i]->two->mode;
  42                         memcpy(p->parent[n].sha1, q->queue[i]->one->sha1, 20);
  43                         p->parent[n].mode = q->queue[i]->one->mode;
  44                         p->parent[n].status = q->queue[i]->status;
  45                         *tail = p;
  46                         tail = &p->next;
  47                 }
  48                 return list;
  49         }
  50
  51         for (p = curr; p; p = p->next) {
  52                 int found = 0;
  53                 if (!p->len)
  54                         continue;
  55                 for (i = 0; i < q->nr; i++) {
  56                         const char *path;
  57                         int len;
  58
  59                         if (uninteresting(q->queue[i]))
  60                                 continue;
  61                         path = q->queue[i]->two->path;
  62                         len = strlen(path);
  63                         if (len == p->len && !memcmp(path, p->path, len)) {
  64                                 found = 1;
  65                                 memcpy(p->parent[n].sha1,
  66                                        q->queue[i]->one->sha1, 20);
  67                                 p->parent[n].mode = q->queue[i]->one->mode;
  68                                 p->parent[n].status = q->queue[i]->status;
  69                                 break;
  70                         }
  71                 }
  72                 if (!found)
  73                         p->len = 0;
  74         }
  75         return curr;
  76 }
  77
  78 /* Lines lost from parent */
  79 struct lline {
  80         struct lline *next;
  81         int len;
  82         unsigned long parent_map;
  83         char line[FLEX_ARRAY];
  84 };
  85
  86 /* Lines surviving in the merge result */
  87 struct sline {
  88         struct lline *lost_head, **lost_tail;
  89         char *bol;
  90         int len;
  91         /* bit 0 up to (N-1) are on if the parent has this line (i.e.
  92          * we did not change it).
  93          * bit N is used for "interesting" lines, including context.
  94          */
  95         unsigned long flag;
  96         unsigned long *p_lno;
  97 };
  98
  99 static char *grab_blob(const unsigned char *sha1, unsigned long *size)
 100 {
 101         char *blob;
 102         char type[20];
 103         if (!memcmp(sha1, null_sha1, 20)) {
 104                 /* deleted blob */
 105                 *size = 0;
 106                 return xcalloc(1, 1);
 107         }
 108         blob = read_sha1_file(sha1, type, size);
 109         if (strcmp(type, blob_type))
 110                 die("object '%s' is not a blob!", sha1_to_hex(sha1));
 111         return blob;
 112 }
 113
 114 static int parse_num(char **cp_p, unsigned int *num_p)
 115 {
 116         char *cp = *cp_p;
 117         unsigned int num = 0;
 118         int read_some;
 119
 120         while ('0' <= *cp && *cp <= '9')
 121                 num = num * 10 + *cp++ - '0';
 122         if (!(read_some = cp - *cp_p))
 123                 return -1;
 124         *cp_p = cp;
 125         *num_p = num;
 126         return 0;
 127 }
 128
 129 static int parse_hunk_header(char *line, int len,
 130                              unsigned int *ob, unsigned int *on,
 131                              unsigned int *nb, unsigned int *nn)
 132 {
 133         char *cp;
 134         cp = line + 4;
 135         if (parse_num(&cp, ob)) {
 136         bad_line:
 137                 return error("malformed diff output: %s", line);
 138         }
 139         if (*cp == ',') {
 140                 cp++;
 141                 if (parse_num(&cp, on))
 142                         goto bad_line;
 143         }
 144         else
 145                 *on = 1;
 146         if (*cp++ != ' ' || *cp++ != '+')
 147                 goto bad_line;
 148         if (parse_num(&cp, nb))
 149                 goto bad_line;
 150         if (*cp == ',') {
 151                 cp++;
 152                 if (parse_num(&cp, nn))
 153                         goto bad_line;
 154         }
 155         else
 156                 *nn = 1;
 157         return -!!memcmp(cp, " @@", 3);
 158 }
 159
 160 static void append_lost(struct sline *sline, int n, const char *line, int len)
 161 {
 162         struct lline *lline;
 163         unsigned long this_mask = (1UL<<n);
 164         if (line[len-1] == '\n')
 165                 len--;
 166
 167         /* Check to see if we can squash things */
 168         if (sline->lost_head) {
 169                 struct lline *last_one = NULL;
 170                 /* We cannot squash it with earlier one */
 171                 for (lline = sline->lost_head;
 172                      lline;
 173                      lline = lline->next)
 174                         if (lline->parent_map & this_mask)
 175                                 last_one = lline;
 176                 lline = last_one ? last_one->next : sline->lost_head;
 177                 while (lline) {
 178                         if (lline->len == len &&
 179                             !memcmp(lline->line, line, len)) {
 180                                 lline->parent_map |= this_mask;
 181                                 return;
 182                         }
 183                         lline = lline->next;
 184                 }
 185         }
 186
 187         lline = xmalloc(sizeof(*lline) + len + 1);
 188         lline->len = len;
 189         lline->next = NULL;
 190         lline->parent_map = this_mask;
 191         memcpy(lline->line, line, len);
 192         lline->line[len] = 0;
 193         *sline->lost_tail = lline;
 194         sline->lost_tail = &lline->next;
 195 }
 196
 197 struct combine_diff_state {
 198         struct xdiff_emit_state xm;
 199
 200         unsigned int lno, ob, on, nb, nn;
 201         unsigned long nmask;
 202         int num_parent;
 203         int n;
 204         struct sline *sline;
 205         struct sline *lost_bucket;
 206 };
 207
 208 static void consume_line(void *state_, char *line, unsigned long len)
 209 {
 210         struct combine_diff_state *state = state_;
 211         if (5 < len && !memcmp("@@ -", line, 4)) {
 212                 if (parse_hunk_header(line, len,
 213                                       &state->ob, &state->on,
 214                                       &state->nb, &state->nn))
 215                         return;
 216                 state->lno = state->nb;
 217                 if (!state->nb)
 218                         /* @@ -1,2 +0,0 @@ to remove the
 219                          * first two lines...
 220                          */
 221                         state->nb = 1;
 222                 if (state->nn == 0)
 223                         /* @@ -X,Y +N,0 @@ removed Y lines
 224                          * that would have come *after* line N
 225                          * in the result.  Our lost buckets hang
 226                          * to the line after the removed lines,
 227                          */
 228                         state->lost_bucket = &state->sline[state->nb];
 229                 else
 230                         state->lost_bucket = &state->sline[state->nb-1];
 231                 if (!state->sline[state->nb-1].p_lno)
 232                         state->sline[state->nb-1].p_lno =
 233                                 xcalloc(state->num_parent,
 234                                         sizeof(unsigned long));
 235                 state->sline[state->nb-1].p_lno[state->n] = state->ob;
 236                 return;
 237         }
 238         if (!state->lost_bucket)
 239                 return; /* not in any hunk yet */
 240         switch (line[0]) {
 241         case '-':
 242                 append_lost(state->lost_bucket, state->n, line+1, len-1);
 243                 break;
 244         case '+':
 245                 state->sline[state->lno-1].flag |= state->nmask;
 246                 state->lno++;
 247                 break;
 248         }
 249 }
 250
 251 static void combine_diff(const unsigned char *parent, mmfile_t *result_file,
 252                          struct sline *sline, int cnt, int n, int num_parent)
 253 {
 254         unsigned int p_lno, lno;
 255         unsigned long nmask = (1UL << n);
 256         xpparam_t xpp;
 257         xdemitconf_t xecfg;
 258         mmfile_t parent_file;
 259         xdemitcb_t ecb;
 260         struct combine_diff_state state;
 261         unsigned long sz;
 262
 263         if (!cnt)
 264                 return; /* result deleted */
 265
 266         parent_file.ptr = grab_blob(parent, &sz);
 267         parent_file.size = sz;
 268         xpp.flags = XDF_NEED_MINIMAL;
 269         xecfg.ctxlen = 0;
 270         xecfg.flags = 0;
 271         ecb.outf = xdiff_outf;
 272         ecb.priv = &state;
 273         memset(&state, 0, sizeof(state));
 274         state.xm.consume = consume_line;
 275         state.nmask = nmask;
 276         state.sline = sline;
 277         state.lno = 1;
 278         state.num_parent = num_parent;
 279         state.n = n;
 280
 281         xdl_diff(&parent_file, result_file, &xpp, &xecfg, &ecb);
 282         free(parent_file.ptr);
 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 result_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         int working_tree_file = !memcmp(elem->sha1, null_sha1, 20);
 634         int abbrev = opt->full_index ? 40 : DEFAULT_ABBREV;
 635         mmfile_t result_file;
 636
 637         /* Read the result of merge first */
 638         if (!working_tree_file)
 639                 result = grab_blob(elem->sha1, &result_size);
 640         else {
 641                 /* Used by diff-tree to read from the working tree */
 642                 struct stat st;
 643                 int fd;
 644                 if (0 <= (fd = open(elem->path, O_RDONLY)) &&
 645                     !fstat(fd, &st)) {
 646                         int len = st.st_size;
 647                         int cnt = 0;
 648
 649                         elem->mode = canon_mode(st.st_mode);
 650                         result_size = len;
 651                         result = xmalloc(len + 1);
 652                         while (cnt < len) {
 653                                 int done = xread(fd, result+cnt, len-cnt);
 654                                 if (done == 0)
 655                                         break;
 656                                 if (done < 0)
 657                                         die("read error '%s'", elem->path);
 658                                 cnt += done;
 659                         }
 660                         result[len] = 0;
 661                 }
 662                 else {
 663                         /* deleted file */
 664                         result_size = 0;
 665                         elem->mode = 0;
 666                         result = xmalloc(1);
 667                         result[0] = 0;
 668                 }
 669                 if (0 <= fd)
 670                         close(fd);
 671         }
 672
 673         for (cnt = 0, cp = result; cp - result < result_size; cp++) {
 674                 if (*cp == '\n')
 675                         cnt++;
 676         }
 677         if (result_size && result[result_size-1] != '\n')
 678                 cnt++; /* incomplete line */
 679
 680         sline = xcalloc(cnt+1, sizeof(*sline));
 681         ep = result;
 682         sline[0].bol = result;
 683         for (lno = 0; lno <= cnt; lno++) {
 684                 sline[lno].lost_tail = &sline[lno].lost_head;
 685                 sline[lno].flag = 0;
 686         }
 687         for (lno = 0, cp = result; cp - result < result_size; cp++) {
 688                 if (*cp == '\n') {
 689                         sline[lno].len = cp - sline[lno].bol;
 690                         lno++;
 691                         if (lno < cnt)
 692                                 sline[lno].bol = cp + 1;
 693                 }
 694         }
 695         if (result_size && result[result_size-1] != '\n')
 696                 sline[cnt-1].len = result_size - (sline[cnt-1].bol - result);
 697
 698         result_file.ptr = result;
 699         result_file.size = result_size;
 700
 701         sline[0].p_lno = xcalloc((cnt+1) * num_parent, sizeof(unsigned long));
 702         for (lno = 0; lno < cnt; lno++)
 703                 sline[lno+1].p_lno = sline[lno].p_lno + num_parent;
 704
 705         for (i = 0; i < num_parent; i++) {
 706                 int j;
 707                 for (j = 0; j < i; j++) {
 708                         if (!memcmp(elem->parent[i].sha1,
 709                                     elem->parent[j].sha1, 20)) {
 710                                 reuse_combine_diff(sline, cnt, i, j);
 711                                 break;
 712                         }
 713                 }
 714                 if (i <= j)
 715                         combine_diff(elem->parent[i].sha1, &result_file, sline,
 716                                      cnt, i, num_parent);
 717                 if (elem->parent[i].mode != elem->mode)
 718                         mode_differs = 1;
 719         }
 720
 721         show_hunks = make_hunks(sline, cnt, num_parent, dense);
 722
 723         if (show_hunks || mode_differs || working_tree_file) {
 724                 const char *abb;
 725
 726                 if (header) {
 727                         shown_header++;
 728                         printf("%s%c", header, opt->line_termination);
 729                 }
 730                 printf("diff --%s ", dense ? "cc" : "combined");
 731                 if (quote_c_style(elem->path, NULL, NULL, 0))
 732                         quote_c_style(elem->path, NULL, stdout, 0);
 733                 else
 734                         printf("%s", elem->path);
 735                 putchar('\n');
 736                 printf("index ");
 737                 for (i = 0; i < num_parent; i++) {
 738                         abb = find_unique_abbrev(elem->parent[i].sha1,
 739                                                  abbrev);
 740                         printf("%s%s", i ? "," : "", abb);
 741                 }
 742                 abb = find_unique_abbrev(elem->sha1, abbrev);
 743                 printf("..%s\n", abb);
 744
 745                 if (mode_differs) {
 746                         int added = !!elem->mode;
 747                         for (i = 0; added && i < num_parent; i++)
 748                                 if (elem->parent[i].status !=
 749                                     DIFF_STATUS_ADDED)
 750                                         added = 0;
 751                         if (added)
 752                                 printf("new file mode %06o", elem->mode);
 753                         else {
 754                                 if (!elem->mode)
 755                                         printf("deleted file ");
 756                                 printf("mode ");
 757                                 for (i = 0; i < num_parent; i++) {
 758                                         printf("%s%06o", i ? "," : "",
 759                                                elem->parent[i].mode);
 760                                 }
 761                                 if (elem->mode)
 762                                         printf("..%06o", elem->mode);
 763                         }
 764                         putchar('\n');
 765                 }
 766                 dump_sline(sline, cnt, num_parent);
 767         }
 768         free(result);
 769
 770         for (i = 0; i < cnt; i++) {
 771                 if (sline[i].lost_head) {
 772                         struct lline *ll = sline[i].lost_head;
 773                         while (ll) {
 774                                 struct lline *tmp = ll;
 775                                 ll = ll->next;
 776                                 free(tmp);
 777                         }
 778                 }
 779         }
 780         free(sline[0].p_lno);
 781         free(sline);
 782         return shown_header;
 783 }
 784
 785 #define COLONS "::::::::::::::::::::::::::::::::"
 786
 787 static void show_raw_diff(struct combine_diff_path *p, int num_parent, const char *header, struct diff_options *opt)
 788 {
 789         int i, offset, mod_type = 'A';
 790         const char *prefix;
 791         int line_termination, inter_name_termination;
 792
 793         line_termination = opt->line_termination;
 794         inter_name_termination = '\t';
 795         if (!line_termination)
 796                 inter_name_termination = 0;
 797
 798         if (header)
 799                 printf("%s%c", header, line_termination);
 800
 801         for (i = 0; i < num_parent; i++) {
 802                 if (p->parent[i].mode)
 803                         mod_type = 'M';
 804         }
 805         if (!p->mode)
 806                 mod_type = 'D';
 807
 808         if (opt->output_format == DIFF_FORMAT_RAW) {
 809                 offset = strlen(COLONS) - num_parent;
 810                 if (offset < 0)
 811                         offset = 0;
 812                 prefix = COLONS + offset;
 813
 814                 /* Show the modes */
 815                 for (i = 0; i < num_parent; i++) {
 816                         printf("%s%06o", prefix, p->parent[i].mode);
 817                         prefix = " ";
 818                 }
 819                 printf("%s%06o", prefix, p->mode);
 820
 821                 /* Show sha1's */
 822                 for (i = 0; i < num_parent; i++)
 823                         printf(" %s", diff_unique_abbrev(p->parent[i].sha1,
 824                                                          opt->abbrev));
 825                 printf(" %s ", diff_unique_abbrev(p->sha1, opt->abbrev));
 826         }
 827
 828         if (opt->output_format == DIFF_FORMAT_RAW ||
 829             opt->output_format == DIFF_FORMAT_NAME_STATUS) {
 830                 for (i = 0; i < num_parent; i++)
 831                         putchar(p->parent[i].status);
 832                 putchar(inter_name_termination);
 833         }
 834
 835         if (line_termination) {
 836                 if (quote_c_style(p->path, NULL, NULL, 0))
 837                         quote_c_style(p->path, NULL, stdout, 0);
 838                 else
 839                         printf("%s", p->path);
 840                 putchar(line_termination);
 841         }
 842         else {
 843                 printf("%s%c", p->path, line_termination);
 844         }
 845 }
 846
 847 int show_combined_diff(struct combine_diff_path *p,
 848                        int num_parent,
 849                        int dense,
 850                        const char *header,
 851                        struct diff_options *opt)
 852 {
 853         if (!p->len)
 854                 return 0;
 855         switch (opt->output_format) {
 856         case DIFF_FORMAT_RAW:
 857         case DIFF_FORMAT_NAME_STATUS:
 858         case DIFF_FORMAT_NAME:
 859                 show_raw_diff(p, num_parent, header, opt);
 860                 return 1;
 861
 862         default:
 863         case DIFF_FORMAT_PATCH:
 864                 return show_patch_diff(p, num_parent, dense, header, opt);
 865         }
 866 }
 867
 868 const char *diff_tree_combined_merge(const unsigned char *sha1,
 869                              const char *header, int dense,
 870                              struct diff_options *opt)
 871 {
 872         struct commit *commit = lookup_commit(sha1);
 873         struct diff_options diffopts;
 874         struct commit_list *parents;
 875         struct combine_diff_path *p, *paths = NULL;
 876         int num_parent, i, num_paths;
 877
 878         diffopts = *opt;
 879         diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
 880         diffopts.recursive = 1;
 881
 882         /* count parents */
 883         for (parents = commit->parents, num_parent = 0;
 884              parents;
 885              parents = parents->next, num_parent++)
 886                 ; /* nothing */
 887
 888         /* find set of paths that everybody touches */
 889         for (parents = commit->parents, i = 0;
 890              parents;
 891              parents = parents->next, i++) {
 892                 struct commit *parent = parents->item;
 893                 diff_tree_sha1(parent->object.sha1, commit->object.sha1, "",
 894                                &diffopts);
 895                 diffcore_std(&diffopts);
 896                 paths = intersect_paths(paths, i, num_parent);
 897                 diff_flush(&diffopts);
 898         }
 899
 900         /* find out surviving paths */
 901         for (num_paths = 0, p = paths; p; p = p->next) {
 902                 if (p->len)
 903                         num_paths++;
 904         }
 905         if (num_paths) {
 906                 for (p = paths; p; p = p->next) {
 907                         if (show_combined_diff(p, num_parent, dense,
 908                                                header, opt))
 909                                 header = NULL;
 910                 }
 911         }
 912
 913         /* Clean things up */
 914         while (paths) {
 915                 struct combine_diff_path *tmp = paths;
 916                 paths = paths->next;
 917                 free(tmp);
 918         }
 919         return header;
 920 }