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