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 "xdiff/xmacros.h"
   9 #include "log-tree.h"
  10 #include "refs.h"
  11 #include "userdiff.h"
  12 #include "sha1-array.h"
  13 #include "revision.h"
  14
  15 static int compare_paths(const struct combine_diff_path *one,
  16                           const struct diff_filespec *two)
  17 {
  18         if (!S_ISDIR(one->mode) && !S_ISDIR(two->mode))
  19                 return strcmp(one->path, two->path);
  20
  21         return base_name_compare(one->path, strlen(one->path), one->mode,
  22                                  two->path, strlen(two->path), two->mode);
  23 }
  24
  25 static struct combine_diff_path *intersect_paths(struct combine_diff_path *curr, int n, int num_parent)
  26 {
  27         struct diff_queue_struct *q = &diff_queued_diff;
  28         struct combine_diff_path *p, **tail = &curr;
  29         int i, cmp;
  30
  31         if (!n) {
  32                 for (i = 0; i < q->nr; i++) {
  33                         int len;
  34                         const char *path;
  35                         if (diff_unmodified_pair(q->queue[i]))
  36                                 continue;
  37                         path = q->queue[i]->two->path;
  38                         len = strlen(path);
  39                         p = xmalloc(combine_diff_path_size(num_parent, len));
  40                         p->path = (char *) &(p->parent[num_parent]);
  41                         memcpy(p->path, path, len);
  42                         p->path[len] = 0;
  43                         p->next = NULL;
  44                         memset(p->parent, 0,
  45                                sizeof(p->parent[0]) * num_parent);
  46
  47                         oidcpy(&p->oid, &q->queue[i]->two->oid);
  48                         p->mode = q->queue[i]->two->mode;
  49                         oidcpy(&p->parent[n].oid, &q->queue[i]->one->oid);
  50                         p->parent[n].mode = q->queue[i]->one->mode;
  51                         p->parent[n].status = q->queue[i]->status;
  52                         *tail = p;
  53                         tail = &p->next;
  54                 }
  55                 return curr;
  56         }
  57
  58         /*
  59          * paths in curr (linked list) and q->queue[] (array) are
  60          * both sorted in the tree order.
  61          */
  62         i = 0;
  63         while ((p = *tail) != NULL) {
  64                 cmp = ((i >= q->nr)
  65                        ? -1 : compare_paths(p, q->queue[i]->two));
  66
  67                 if (cmp < 0) {
  68                         /* p->path not in q->queue[]; drop it */
  69                         *tail = p->next;
  70                         free(p);
  71                         continue;
  72                 }
  73
  74                 if (cmp > 0) {
  75                         /* q->queue[i] not in p->path; skip it */
  76                         i++;
  77                         continue;
  78                 }
  79
  80                 oidcpy(&p->parent[n].oid, &q->queue[i]->one->oid);
  81                 p->parent[n].mode = q->queue[i]->one->mode;
  82                 p->parent[n].status = q->queue[i]->status;
  83
  84                 tail = &p->next;
  85                 i++;
  86         }
  87         return curr;
  88 }
  89
  90 /* Lines lost from parent */
  91 struct lline {
  92         struct lline *next, *prev;
  93         int len;
  94         unsigned long parent_map;
  95         char line[FLEX_ARRAY];
  96 };
  97
  98 /* Lines lost from current parent (before coalescing) */
  99 struct plost {
 100         struct lline *lost_head, *lost_tail;
 101         int len;
 102 };
 103
 104 /* Lines surviving in the merge result */
 105 struct sline {
 106         /* Accumulated and coalesced lost lines */
 107         struct lline *lost;
 108         int lenlost;
 109         struct plost plost;
 110         char *bol;
 111         int len;
 112         /* bit 0 up to (N-1) are on if the parent has this line (i.e.
 113          * we did not change it).
 114          * bit N is used for "interesting" lines, including context.
 115          * bit (N+1) is used for "do not show deletion before this".
 116          */
 117         unsigned long flag;
 118         unsigned long *p_lno;
 119 };
 120
 121 static int match_string_spaces(const char *line1, int len1,
 122                                const char *line2, int len2,
 123                                long flags)
 124 {
 125         if (flags & XDF_WHITESPACE_FLAGS) {
 126                 for (; len1 > 0 && XDL_ISSPACE(line1[len1 - 1]); len1--);
 127                 for (; len2 > 0 && XDL_ISSPACE(line2[len2 - 1]); len2--);
 128         }
 129
 130         if (!(flags & (XDF_IGNORE_WHITESPACE | XDF_IGNORE_WHITESPACE_CHANGE)))
 131                 return (len1 == len2 && !memcmp(line1, line2, len1));
 132
 133         while (len1 > 0 && len2 > 0) {
 134                 len1--;
 135                 len2--;
 136                 if (XDL_ISSPACE(line1[len1]) || XDL_ISSPACE(line2[len2])) {
 137                         if ((flags & XDF_IGNORE_WHITESPACE_CHANGE) &&
 138                             (!XDL_ISSPACE(line1[len1]) || !XDL_ISSPACE(line2[len2])))
 139                                 return 0;
 140
 141                         for (; len1 > 0 && XDL_ISSPACE(line1[len1]); len1--);
 142                         for (; len2 > 0 && XDL_ISSPACE(line2[len2]); len2--);
 143                 }
 144                 if (line1[len1] != line2[len2])
 145                         return 0;
 146         }
 147
 148         if (flags & XDF_IGNORE_WHITESPACE) {
 149                 /* Consume remaining spaces */
 150                 for (; len1 > 0 && XDL_ISSPACE(line1[len1 - 1]); len1--);
 151                 for (; len2 > 0 && XDL_ISSPACE(line2[len2 - 1]); len2--);
 152         }
 153
 154         /* We matched full line1 and line2 */
 155         if (!len1 && !len2)
 156                 return 1;
 157
 158         return 0;
 159 }
 160
 161 enum coalesce_direction { MATCH, BASE, NEW };
 162
 163 /* Coalesce new lines into base by finding LCS */
 164 static struct lline *coalesce_lines(struct lline *base, int *lenbase,
 165                                     struct lline *newline, int lennew,
 166                                     unsigned long parent, long flags)
 167 {
 168         int **lcs;
 169         enum coalesce_direction **directions;
 170         struct lline *baseend, *newend = NULL;
 171         int i, j, origbaselen = *lenbase;
 172
 173         if (newline == NULL)
 174                 return base;
 175
 176         if (base == NULL) {
 177                 *lenbase = lennew;
 178                 return newline;
 179         }
 180
 181         /*
 182          * Coalesce new lines into base by finding the LCS
 183          * - Create the table to run dynamic programming
 184          * - Compute the LCS
 185          * - Then reverse read the direction structure:
 186          *   - If we have MATCH, assign parent to base flag, and consume
 187          *   both baseend and newend
 188          *   - Else if we have BASE, consume baseend
 189          *   - Else if we have NEW, insert newend lline into base and
 190          *   consume newend
 191          */
 192         lcs = xcalloc(st_add(origbaselen, 1), sizeof(int*));
 193         directions = xcalloc(st_add(origbaselen, 1), sizeof(enum coalesce_direction*));
 194         for (i = 0; i < origbaselen + 1; i++) {
 195                 lcs[i] = xcalloc(st_add(lennew, 1), sizeof(int));
 196                 directions[i] = xcalloc(st_add(lennew, 1), sizeof(enum coalesce_direction));
 197                 directions[i][0] = BASE;
 198         }
 199         for (j = 1; j < lennew + 1; j++)
 200                 directions[0][j] = NEW;
 201
 202         for (i = 1, baseend = base; i < origbaselen + 1; i++) {
 203                 for (j = 1, newend = newline; j < lennew + 1; j++) {
 204                         if (match_string_spaces(baseend->line, baseend->len,
 205                                                 newend->line, newend->len, flags)) {
 206                                 lcs[i][j] = lcs[i - 1][j - 1] + 1;
 207                                 directions[i][j] = MATCH;
 208                         } else if (lcs[i][j - 1] >= lcs[i - 1][j]) {
 209                                 lcs[i][j] = lcs[i][j - 1];
 210                                 directions[i][j] = NEW;
 211                         } else {
 212                                 lcs[i][j] = lcs[i - 1][j];
 213                                 directions[i][j] = BASE;
 214                         }
 215                         if (newend->next)
 216                                 newend = newend->next;
 217                 }
 218                 if (baseend->next)
 219                         baseend = baseend->next;
 220         }
 221
 222         for (i = 0; i < origbaselen + 1; i++)
 223                 free(lcs[i]);
 224         free(lcs);
 225
 226         /* At this point, baseend and newend point to the end of each lists */
 227         i--;
 228         j--;
 229         while (i != 0 || j != 0) {
 230                 if (directions[i][j] == MATCH) {
 231                         baseend->parent_map |= 1<<parent;
 232                         baseend = baseend->prev;
 233                         newend = newend->prev;
 234                         i--;
 235                         j--;
 236                 } else if (directions[i][j] == NEW) {
 237                         struct lline *lline;
 238
 239                         lline = newend;
 240                         /* Remove lline from new list and update newend */
 241                         if (lline->prev)
 242                                 lline->prev->next = lline->next;
 243                         else
 244                                 newline = lline->next;
 245                         if (lline->next)
 246                                 lline->next->prev = lline->prev;
 247
 248                         newend = lline->prev;
 249                         j--;
 250
 251                         /* Add lline to base list */
 252                         if (baseend) {
 253                                 lline->next = baseend->next;
 254                                 lline->prev = baseend;
 255                                 if (lline->prev)
 256                                         lline->prev->next = lline;
 257                         }
 258                         else {
 259                                 lline->next = base;
 260                                 base = lline;
 261                         }
 262                         (*lenbase)++;
 263
 264                         if (lline->next)
 265                                 lline->next->prev = lline;
 266
 267                 } else {
 268                         baseend = baseend->prev;
 269                         i--;
 270                 }
 271         }
 272
 273         newend = newline;
 274         while (newend) {
 275                 struct lline *lline = newend;
 276                 newend = newend->next;
 277                 free(lline);
 278         }
 279
 280         for (i = 0; i < origbaselen + 1; i++)
 281                 free(directions[i]);
 282         free(directions);
 283
 284         return base;
 285 }
 286
 287 static char *grab_blob(const struct object_id *oid, unsigned int mode,
 288                        unsigned long *size, struct userdiff_driver *textconv,
 289                        const char *path)
 290 {
 291         char *blob;
 292         enum object_type type;
 293
 294         if (S_ISGITLINK(mode)) {
 295                 struct strbuf buf = STRBUF_INIT;
 296                 strbuf_addf(&buf, "Subproject commit %s\n", oid_to_hex(oid));
 297                 *size = buf.len;
 298                 blob = strbuf_detach(&buf, NULL);
 299         } else if (is_null_oid(oid)) {
 300                 /* deleted blob */
 301                 *size = 0;
 302                 return xcalloc(1, 1);
 303         } else if (textconv) {
 304                 struct diff_filespec *df = alloc_filespec(path);
 305                 fill_filespec(df, oid, 1, mode);
 306                 *size = fill_textconv(textconv, df, &blob);
 307                 free_filespec(df);
 308         } else {
 309                 blob = read_object_file(oid, &type, size);
 310                 if (type != OBJ_BLOB)
 311                         die("object '%s' is not a blob!", oid_to_hex(oid));
 312         }
 313         return blob;
 314 }
 315
 316 static void append_lost(struct sline *sline, int n, const char *line, int len)
 317 {
 318         struct lline *lline;
 319         unsigned long this_mask = (1UL<<n);
 320         if (line[len-1] == '\n')
 321                 len--;
 322
 323         FLEX_ALLOC_MEM(lline, line, line, len);
 324         lline->len = len;
 325         lline->next = NULL;
 326         lline->prev = sline->plost.lost_tail;
 327         if (lline->prev)
 328                 lline->prev->next = lline;
 329         else
 330                 sline->plost.lost_head = lline;
 331         sline->plost.lost_tail = lline;
 332         sline->plost.len++;
 333         lline->parent_map = this_mask;
 334 }
 335
 336 struct combine_diff_state {
 337         unsigned int lno;
 338         int ob, on, nb, nn;
 339         unsigned long nmask;
 340         int num_parent;
 341         int n;
 342         struct sline *sline;
 343         struct sline *lost_bucket;
 344 };
 345
 346 static void consume_line(void *state_, char *line, unsigned long len)
 347 {
 348         struct combine_diff_state *state = state_;
 349         if (5 < len && !memcmp("@@ -", line, 4)) {
 350                 if (parse_hunk_header(line, len,
 351                                       &state->ob, &state->on,
 352                                       &state->nb, &state->nn))
 353                         return;
 354                 state->lno = state->nb;
 355                 if (state->nn == 0) {
 356                         /* @@ -X,Y +N,0 @@ removed Y lines
 357                          * that would have come *after* line N
 358                          * in the result.  Our lost buckets hang
 359                          * to the line after the removed lines,
 360                          *
 361                          * Note that this is correct even when N == 0,
 362                          * in which case the hunk removes the first
 363                          * line in the file.
 364                          */
 365                         state->lost_bucket = &state->sline[state->nb];
 366                         if (!state->nb)
 367                                 state->nb = 1;
 368                 } else {
 369                         state->lost_bucket = &state->sline[state->nb-1];
 370                 }
 371                 if (!state->sline[state->nb-1].p_lno)
 372                         state->sline[state->nb-1].p_lno =
 373                                 xcalloc(state->num_parent,
 374                                         sizeof(unsigned long));
 375                 state->sline[state->nb-1].p_lno[state->n] = state->ob;
 376                 return;
 377         }
 378         if (!state->lost_bucket)
 379                 return; /* not in any hunk yet */
 380         switch (line[0]) {
 381         case '-':
 382                 append_lost(state->lost_bucket, state->n, line+1, len-1);
 383                 break;
 384         case '+':
 385                 state->sline[state->lno-1].flag |= state->nmask;
 386                 state->lno++;
 387                 break;
 388         }
 389 }
 390
 391 static void combine_diff(const struct object_id *parent, unsigned int mode,
 392                          mmfile_t *result_file,
 393                          struct sline *sline, unsigned int cnt, int n,
 394                          int num_parent, int result_deleted,
 395                          struct userdiff_driver *textconv,
 396                          const char *path, long flags)
 397 {
 398         unsigned int p_lno, lno;
 399         unsigned long nmask = (1UL << n);
 400         xpparam_t xpp;
 401         xdemitconf_t xecfg;
 402         mmfile_t parent_file;
 403         struct combine_diff_state state;
 404         unsigned long sz;
 405
 406         if (result_deleted)
 407                 return; /* result deleted */
 408
 409         parent_file.ptr = grab_blob(parent, mode, &sz, textconv, path);
 410         parent_file.size = sz;
 411         memset(&xpp, 0, sizeof(xpp));
 412         xpp.flags = flags;
 413         memset(&xecfg, 0, sizeof(xecfg));
 414         memset(&state, 0, sizeof(state));
 415         state.nmask = nmask;
 416         state.sline = sline;
 417         state.lno = 1;
 418         state.num_parent = num_parent;
 419         state.n = n;
 420
 421         if (xdi_diff_outf(&parent_file, result_file, consume_line, &state,
 422                           &xpp, &xecfg))
 423                 die("unable to generate combined diff for %s",
 424                     oid_to_hex(parent));
 425         free(parent_file.ptr);
 426
 427         /* Assign line numbers for this parent.
 428          *
 429          * sline[lno].p_lno[n] records the first line number
 430          * (counting from 1) for parent N if the final hunk display
 431          * started by showing sline[lno] (possibly showing the lost
 432          * lines attached to it first).
 433          */
 434         for (lno = 0,  p_lno = 1; lno <= cnt; lno++) {
 435                 struct lline *ll;
 436                 sline[lno].p_lno[n] = p_lno;
 437
 438                 /* Coalesce new lines */
 439                 if (sline[lno].plost.lost_head) {
 440                         struct sline *sl = &sline[lno];
 441                         sl->lost = coalesce_lines(sl->lost, &sl->lenlost,
 442                                                   sl->plost.lost_head,
 443                                                   sl->plost.len, n, flags);
 444                         sl->plost.lost_head = sl->plost.lost_tail = NULL;
 445                         sl->plost.len = 0;
 446                 }
 447
 448                 /* How many lines would this sline advance the p_lno? */
 449                 ll = sline[lno].lost;
 450                 while (ll) {
 451                         if (ll->parent_map & nmask)
 452                                 p_lno++; /* '-' means parent had it */
 453                         ll = ll->next;
 454                 }
 455                 if (lno < cnt && !(sline[lno].flag & nmask))
 456                         p_lno++; /* no '+' means parent had it */
 457         }
 458         sline[lno].p_lno[n] = p_lno; /* trailer */
 459 }
 460
 461 static unsigned long context = 3;
 462 static char combine_marker = '@';
 463
 464 static int interesting(struct sline *sline, unsigned long all_mask)
 465 {
 466         /* If some parents lost lines here, or if we have added to
 467          * some parent, it is interesting.
 468          */
 469         return ((sline->flag & all_mask) || sline->lost);
 470 }
 471
 472 static unsigned long adjust_hunk_tail(struct sline *sline,
 473                                       unsigned long all_mask,
 474                                       unsigned long hunk_begin,
 475                                       unsigned long i)
 476 {
 477         /* i points at the first uninteresting line.  If the last line
 478          * of the hunk was interesting only because it has some
 479          * deletion, then it is not all that interesting for the
 480          * purpose of giving trailing context lines.  This is because
 481          * we output '-' line and then unmodified sline[i-1] itself in
 482          * that case which gives us one extra context line.
 483          */
 484         if ((hunk_begin + 1 <= i) && !(sline[i-1].flag & all_mask))
 485                 i--;
 486         return i;
 487 }
 488
 489 static unsigned long find_next(struct sline *sline,
 490                                unsigned long mark,
 491                                unsigned long i,
 492                                unsigned long cnt,
 493                                int look_for_uninteresting)
 494 {
 495         /* We have examined up to i-1 and are about to look at i.
 496          * Find next interesting or uninteresting line.  Here,
 497          * "interesting" does not mean interesting(), but marked by
 498          * the give_context() function below (i.e. it includes context
 499          * lines that are not interesting to interesting() function
 500          * that are surrounded by interesting() ones.
 501          */
 502         while (i <= cnt)
 503                 if (look_for_uninteresting
 504                     ? !(sline[i].flag & mark)
 505                     : (sline[i].flag & mark))
 506                         return i;
 507                 else
 508                         i++;
 509         return i;
 510 }
 511
 512 static int give_context(struct sline *sline, unsigned long cnt, int num_parent)
 513 {
 514         unsigned long all_mask = (1UL<<num_parent) - 1;
 515         unsigned long mark = (1UL<<num_parent);
 516         unsigned long no_pre_delete = (2UL<<num_parent);
 517         unsigned long i;
 518
 519         /* Two groups of interesting lines may have a short gap of
 520          * uninteresting lines.  Connect such groups to give them a
 521          * bit of context.
 522          *
 523          * We first start from what the interesting() function says,
 524          * and mark them with "mark", and paint context lines with the
 525          * mark.  So interesting() would still say false for such context
 526          * lines but they are treated as "interesting" in the end.
 527          */
 528         i = find_next(sline, mark, 0, cnt, 0);
 529         if (cnt < i)
 530                 return 0;
 531
 532         while (i <= cnt) {
 533                 unsigned long j = (context < i) ? (i - context) : 0;
 534                 unsigned long k;
 535
 536                 /* Paint a few lines before the first interesting line. */
 537                 while (j < i) {
 538                         if (!(sline[j].flag & mark))
 539                                 sline[j].flag |= no_pre_delete;
 540                         sline[j++].flag |= mark;
 541                 }
 542
 543         again:
 544                 /* we know up to i is to be included.  where does the
 545                  * next uninteresting one start?
 546                  */
 547                 j = find_next(sline, mark, i, cnt, 1);
 548                 if (cnt < j)
 549                         break; /* the rest are all interesting */
 550
 551                 /* lookahead context lines */
 552                 k = find_next(sline, mark, j, cnt, 0);
 553                 j = adjust_hunk_tail(sline, all_mask, i, j);
 554
 555                 if (k < j + context) {
 556                         /* k is interesting and [j,k) are not, but
 557                          * paint them interesting because the gap is small.
 558                          */
 559                         while (j < k)
 560                                 sline[j++].flag |= mark;
 561                         i = k;
 562                         goto again;
 563                 }
 564
 565                 /* j is the first uninteresting line and there is
 566                  * no overlap beyond it within context lines.  Paint
 567                  * the trailing edge a bit.
 568                  */
 569                 i = k;
 570                 k = (j + context < cnt+1) ? j + context : cnt+1;
 571                 while (j < k)
 572                         sline[j++].flag |= mark;
 573         }
 574         return 1;
 575 }
 576
 577 static int make_hunks(struct sline *sline, unsigned long cnt,
 578                        int num_parent, int dense)
 579 {
 580         unsigned long all_mask = (1UL<<num_parent) - 1;
 581         unsigned long mark = (1UL<<num_parent);
 582         unsigned long i;
 583         int has_interesting = 0;
 584
 585         for (i = 0; i <= cnt; i++) {
 586                 if (interesting(&sline[i], all_mask))
 587                         sline[i].flag |= mark;
 588                 else
 589                         sline[i].flag &= ~mark;
 590         }
 591         if (!dense)
 592                 return give_context(sline, cnt, num_parent);
 593
 594         /* Look at each hunk, and if we have changes from only one
 595          * parent, or the changes are the same from all but one
 596          * parent, mark that uninteresting.
 597          */
 598         i = 0;
 599         while (i <= cnt) {
 600                 unsigned long j, hunk_begin, hunk_end;
 601                 unsigned long same_diff;
 602                 while (i <= cnt && !(sline[i].flag & mark))
 603                         i++;
 604                 if (cnt < i)
 605                         break; /* No more interesting hunks */
 606                 hunk_begin = i;
 607                 for (j = i + 1; j <= cnt; j++) {
 608                         if (!(sline[j].flag & mark)) {
 609                                 /* Look beyond the end to see if there
 610                                  * is an interesting line after this
 611                                  * hunk within context span.
 612                                  */
 613                                 unsigned long la; /* lookahead */
 614                                 int contin = 0;
 615                                 la = adjust_hunk_tail(sline, all_mask,
 616                                                      hunk_begin, j);
 617                                 la = (la + context < cnt + 1) ?
 618                                         (la + context) : cnt + 1;
 619                                 while (la && j <= --la) {
 620                                         if (sline[la].flag & mark) {
 621                                                 contin = 1;
 622                                                 break;
 623                                         }
 624                                 }
 625                                 if (!contin)
 626                                         break;
 627                                 j = la;
 628                         }
 629                 }
 630                 hunk_end = j;
 631
 632                 /* [i..hunk_end) are interesting.  Now is it really
 633                  * interesting?  We check if there are only two versions
 634                  * and the result matches one of them.  That is, we look
 635                  * at:
 636                  *   (+) line, which records lines added to which parents;
 637                  *       this line appears in the result.
 638                  *   (-) line, which records from what parents the line
 639                  *       was removed; this line does not appear in the result.
 640                  * then check the set of parents the result has difference
 641                  * from, from all lines.  If there are lines that has
 642                  * different set of parents that the result has differences
 643                  * from, that means we have more than two versions.
 644                  *
 645                  * Even when we have only two versions, if the result does
 646                  * not match any of the parents, the it should be considered
 647                  * interesting.  In such a case, we would have all '+' line.
 648                  * After passing the above "two versions" test, that would
 649                  * appear as "the same set of parents" to be "all parents".
 650                  */
 651                 same_diff = 0;
 652                 has_interesting = 0;
 653                 for (j = i; j < hunk_end && !has_interesting; j++) {
 654                         unsigned long this_diff = sline[j].flag & all_mask;
 655                         struct lline *ll = sline[j].lost;
 656                         if (this_diff) {
 657                                 /* This has some changes.  Is it the
 658                                  * same as others?
 659                                  */
 660                                 if (!same_diff)
 661                                         same_diff = this_diff;
 662                                 else if (same_diff != this_diff) {
 663                                         has_interesting = 1;
 664                                         break;
 665                                 }
 666                         }
 667                         while (ll && !has_interesting) {
 668                                 /* Lost this line from these parents;
 669                                  * who are they?  Are they the same?
 670                                  */
 671                                 this_diff = ll->parent_map;
 672                                 if (!same_diff)
 673                                         same_diff = this_diff;
 674                                 else if (same_diff != this_diff) {
 675                                         has_interesting = 1;
 676                                 }
 677                                 ll = ll->next;
 678                         }
 679                 }
 680
 681                 if (!has_interesting && same_diff != all_mask) {
 682                         /* This hunk is not that interesting after all */
 683                         for (j = hunk_begin; j < hunk_end; j++)
 684                                 sline[j].flag &= ~mark;
 685                 }
 686                 i = hunk_end;
 687         }
 688
 689         has_interesting = give_context(sline, cnt, num_parent);
 690         return has_interesting;
 691 }
 692
 693 static void show_parent_lno(struct sline *sline, unsigned long l0, unsigned long l1, int n, unsigned long null_context)
 694 {
 695         l0 = sline[l0].p_lno[n];
 696         l1 = sline[l1].p_lno[n];
 697         printf(" -%lu,%lu", l0, l1-l0-null_context);
 698 }
 699
 700 static int hunk_comment_line(const char *bol)
 701 {
 702         int ch;
 703
 704         if (!bol)
 705                 return 0;
 706         ch = *bol & 0xff;
 707         return (isalpha(ch) || ch == '_' || ch == '$');
 708 }
 709
 710 static void show_line_to_eol(const char *line, int len, const char *reset)
 711 {
 712         int saw_cr_at_eol = 0;
 713         if (len < 0)
 714                 len = strlen(line);
 715         saw_cr_at_eol = (len && line[len-1] == '\r');
 716
 717         printf("%.*s%s%s\n", len - saw_cr_at_eol, line,
 718                reset,
 719                saw_cr_at_eol ? "\r" : "");
 720 }
 721
 722 static void dump_sline(struct sline *sline, const char *line_prefix,
 723                        unsigned long cnt, int num_parent,
 724                        int use_color, int result_deleted)
 725 {
 726         unsigned long mark = (1UL<<num_parent);
 727         unsigned long no_pre_delete = (2UL<<num_parent);
 728         int i;
 729         unsigned long lno = 0;
 730         const char *c_frag = diff_get_color(use_color, DIFF_FRAGINFO);
 731         const char *c_func = diff_get_color(use_color, DIFF_FUNCINFO);
 732         const char *c_new = diff_get_color(use_color, DIFF_FILE_NEW);
 733         const char *c_old = diff_get_color(use_color, DIFF_FILE_OLD);
 734         const char *c_context = diff_get_color(use_color, DIFF_CONTEXT);
 735         const char *c_reset = diff_get_color(use_color, DIFF_RESET);
 736
 737         if (result_deleted)
 738                 return; /* result deleted */
 739
 740         while (1) {
 741                 unsigned long hunk_end;
 742                 unsigned long rlines;
 743                 const char *hunk_comment = NULL;
 744                 unsigned long null_context = 0;
 745
 746                 while (lno <= cnt && !(sline[lno].flag & mark)) {
 747                         if (hunk_comment_line(sline[lno].bol))
 748                                 hunk_comment = sline[lno].bol;
 749                         lno++;
 750                 }
 751                 if (cnt < lno)
 752                         break;
 753                 else {
 754                         for (hunk_end = lno + 1; hunk_end <= cnt; hunk_end++)
 755                                 if (!(sline[hunk_end].flag & mark))
 756                                         break;
 757                 }
 758                 rlines = hunk_end - lno;
 759                 if (cnt < hunk_end)
 760                         rlines--; /* pointing at the last delete hunk */
 761
 762                 if (!context) {
 763                         /*
 764                          * Even when running with --unified=0, all
 765                          * lines in the hunk needs to be processed in
 766                          * the loop below in order to show the
 767                          * deletion recorded in lost_head.  However,
 768                          * we do not want to show the resulting line
 769                          * with all blank context markers in such a
 770                          * case.  Compensate.
 771                          */
 772                         unsigned long j;
 773                         for (j = lno; j < hunk_end; j++)
 774                                 if (!(sline[j].flag & (mark-1)))
 775                                         null_context++;
 776                         rlines -= null_context;
 777                 }
 778
 779                 printf("%s%s", line_prefix, c_frag);
 780                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 781                 for (i = 0; i < num_parent; i++)
 782                         show_parent_lno(sline, lno, hunk_end, i, null_context);
 783                 printf(" +%lu,%lu ", lno+1, rlines);
 784                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 785
 786                 if (hunk_comment) {
 787                         int comment_end = 0;
 788                         for (i = 0; i < 40; i++) {
 789                                 int ch = hunk_comment[i] & 0xff;
 790                                 if (!ch || ch == '\n')
 791                                         break;
 792                                 if (!isspace(ch))
 793                                     comment_end = i;
 794                         }
 795                         if (comment_end)
 796                                 printf("%s%s %s%s", c_reset,
 797                                                     c_context, c_reset,
 798                                                     c_func);
 799                         for (i = 0; i < comment_end; i++)
 800                                 putchar(hunk_comment[i]);
 801                 }
 802
 803                 printf("%s\n", c_reset);
 804                 while (lno < hunk_end) {
 805                         struct lline *ll;
 806                         int j;
 807                         unsigned long p_mask;
 808                         struct sline *sl = &sline[lno++];
 809                         ll = (sl->flag & no_pre_delete) ? NULL : sl->lost;
 810                         while (ll) {
 811                                 printf("%s%s", line_prefix, c_old);
 812                                 for (j = 0; j < num_parent; j++) {
 813                                         if (ll->parent_map & (1UL<<j))
 814                                                 putchar('-');
 815                                         else
 816                                                 putchar(' ');
 817                                 }
 818                                 show_line_to_eol(ll->line, -1, c_reset);
 819                                 ll = ll->next;
 820                         }
 821                         if (cnt < lno)
 822                                 break;
 823                         p_mask = 1;
 824                         fputs(line_prefix, stdout);
 825                         if (!(sl->flag & (mark-1))) {
 826                                 /*
 827                                  * This sline was here to hang the
 828                                  * lost lines in front of it.
 829                                  */
 830                                 if (!context)
 831                                         continue;
 832                                 fputs(c_context, stdout);
 833                         }
 834                         else
 835                                 fputs(c_new, stdout);
 836                         for (j = 0; j < num_parent; j++) {
 837                                 if (p_mask & sl->flag)
 838                                         putchar('+');
 839                                 else
 840                                         putchar(' ');
 841                                 p_mask <<= 1;
 842                         }
 843                         show_line_to_eol(sl->bol, sl->len, c_reset);
 844                 }
 845         }
 846 }
 847
 848 static void reuse_combine_diff(struct sline *sline, unsigned long cnt,
 849                                int i, int j)
 850 {
 851         /* We have already examined parent j and we know parent i
 852          * and parent j are the same, so reuse the combined result
 853          * of parent j for parent i.
 854          */
 855         unsigned long lno, imask, jmask;
 856         imask = (1UL<<i);
 857         jmask = (1UL<<j);
 858
 859         for (lno = 0; lno <= cnt; lno++) {
 860                 struct lline *ll = sline->lost;
 861                 sline->p_lno[i] = sline->p_lno[j];
 862                 while (ll) {
 863                         if (ll->parent_map & jmask)
 864                                 ll->parent_map |= imask;
 865                         ll = ll->next;
 866                 }
 867                 if (sline->flag & jmask)
 868                         sline->flag |= imask;
 869                 sline++;
 870         }
 871         /* the overall size of the file (sline[cnt]) */
 872         sline->p_lno[i] = sline->p_lno[j];
 873 }
 874
 875 static void dump_quoted_path(const char *head,
 876                              const char *prefix,
 877                              const char *path,
 878                              const char *line_prefix,
 879                              const char *c_meta, const char *c_reset)
 880 {
 881         static struct strbuf buf = STRBUF_INIT;
 882
 883         strbuf_reset(&buf);
 884         strbuf_addstr(&buf, line_prefix);
 885         strbuf_addstr(&buf, c_meta);
 886         strbuf_addstr(&buf, head);
 887         quote_two_c_style(&buf, prefix, path, 0);
 888         strbuf_addstr(&buf, c_reset);
 889         puts(buf.buf);
 890 }
 891
 892 static void show_combined_header(struct combine_diff_path *elem,
 893                                  int num_parent,
 894                                  int dense,
 895                                  struct rev_info *rev,
 896                                  const char *line_prefix,
 897                                  int mode_differs,
 898                                  int show_file_header)
 899 {
 900         struct diff_options *opt = &rev->diffopt;
 901         int abbrev = opt->flags.full_index ? GIT_SHA1_HEXSZ : DEFAULT_ABBREV;
 902         const char *a_prefix = opt->a_prefix ? opt->a_prefix : "a/";
 903         const char *b_prefix = opt->b_prefix ? opt->b_prefix : "b/";
 904         const char *c_meta = diff_get_color_opt(opt, DIFF_METAINFO);
 905         const char *c_reset = diff_get_color_opt(opt, DIFF_RESET);
 906         const char *abb;
 907         int added = 0;
 908         int deleted = 0;
 909         int i;
 910
 911         if (rev->loginfo && !rev->no_commit_id)
 912                 show_log(rev);
 913
 914         dump_quoted_path(dense ? "diff --cc " : "diff --combined ",
 915                          "", elem->path, line_prefix, c_meta, c_reset);
 916         printf("%s%sindex ", line_prefix, c_meta);
 917         for (i = 0; i < num_parent; i++) {
 918                 abb = find_unique_abbrev(&elem->parent[i].oid,
 919                                          abbrev);
 920                 printf("%s%s", i ? "," : "", abb);
 921         }
 922         abb = find_unique_abbrev(&elem->oid, abbrev);
 923         printf("..%s%s\n", abb, c_reset);
 924
 925         if (mode_differs) {
 926                 deleted = !elem->mode;
 927
 928                 /* We say it was added if nobody had it */
 929                 added = !deleted;
 930                 for (i = 0; added && i < num_parent; i++)
 931                         if (elem->parent[i].status !=
 932                             DIFF_STATUS_ADDED)
 933                                 added = 0;
 934                 if (added)
 935                         printf("%s%snew file mode %06o",
 936                                line_prefix, c_meta, elem->mode);
 937                 else {
 938                         if (deleted)
 939                                 printf("%s%sdeleted file ",
 940                                        line_prefix, c_meta);
 941                         printf("mode ");
 942                         for (i = 0; i < num_parent; i++) {
 943                                 printf("%s%06o", i ? "," : "",
 944                                        elem->parent[i].mode);
 945                         }
 946                         if (elem->mode)
 947                                 printf("..%06o", elem->mode);
 948                 }
 949                 printf("%s\n", c_reset);
 950         }
 951
 952         if (!show_file_header)
 953                 return;
 954
 955         if (added)
 956                 dump_quoted_path("--- ", "", "/dev/null",
 957                                  line_prefix, c_meta, c_reset);
 958         else
 959                 dump_quoted_path("--- ", a_prefix, elem->path,
 960                                  line_prefix, c_meta, c_reset);
 961         if (deleted)
 962                 dump_quoted_path("+++ ", "", "/dev/null",
 963                                  line_prefix, c_meta, c_reset);
 964         else
 965                 dump_quoted_path("+++ ", b_prefix, elem->path,
 966                                  line_prefix, c_meta, c_reset);
 967 }
 968
 969 static void show_patch_diff(struct combine_diff_path *elem, int num_parent,
 970                             int dense, int working_tree_file,
 971                             struct rev_info *rev)
 972 {
 973         struct diff_options *opt = &rev->diffopt;
 974         unsigned long result_size, cnt, lno;
 975         int result_deleted = 0;
 976         char *result, *cp;
 977         struct sline *sline; /* survived lines */
 978         int mode_differs = 0;
 979         int i, show_hunks;
 980         mmfile_t result_file;
 981         struct userdiff_driver *userdiff;
 982         struct userdiff_driver *textconv = NULL;
 983         int is_binary;
 984         const char *line_prefix = diff_line_prefix(opt);
 985
 986         context = opt->context;
 987         userdiff = userdiff_find_by_path(elem->path);
 988         if (!userdiff)
 989                 userdiff = userdiff_find_by_name("default");
 990         if (opt->flags.allow_textconv)
 991                 textconv = userdiff_get_textconv(userdiff);
 992
 993         /* Read the result of merge first */
 994         if (!working_tree_file)
 995                 result = grab_blob(&elem->oid, elem->mode, &result_size,
 996                                    textconv, elem->path);
 997         else {
 998                 /* Used by diff-tree to read from the working tree */
 999                 struct stat st;
1000                 int fd = -1;
1001
1002                 if (lstat(elem->path, &st) < 0)
1003                         goto deleted_file;
1004
1005                 if (S_ISLNK(st.st_mode)) {
1006                         struct strbuf buf = STRBUF_INIT;
1007
1008                         if (strbuf_readlink(&buf, elem->path, st.st_size) < 0) {
1009                                 error_errno("readlink(%s)", elem->path);
1010                                 return;
1011                         }
1012                         result_size = buf.len;
1013                         result = strbuf_detach(&buf, NULL);
1014                         elem->mode = canon_mode(st.st_mode);
1015                 } else if (S_ISDIR(st.st_mode)) {
1016                         struct object_id oid;
1017                         if (resolve_gitlink_ref(elem->path, "HEAD", &oid) < 0)
1018                                 result = grab_blob(&elem->oid, elem->mode,
1019                                                    &result_size, NULL, NULL);
1020                         else
1021                                 result = grab_blob(&oid, elem->mode,
1022                                                    &result_size, NULL, NULL);
1023                 } else if (textconv) {
1024                         struct diff_filespec *df = alloc_filespec(elem->path);
1025                         fill_filespec(df, &null_oid, 0, st.st_mode);
1026                         result_size = fill_textconv(textconv, df, &result);
1027                         free_filespec(df);
1028                 } else if (0 <= (fd = open(elem->path, O_RDONLY))) {
1029                         size_t len = xsize_t(st.st_size);
1030                         ssize_t done;
1031                         int is_file, i;
1032
1033                         elem->mode = canon_mode(st.st_mode);
1034                         /* if symlinks don't work, assume symlink if all parents
1035                          * are symlinks
1036                          */
1037                         is_file = has_symlinks;
1038                         for (i = 0; !is_file && i < num_parent; i++)
1039                                 is_file = !S_ISLNK(elem->parent[i].mode);
1040                         if (!is_file)
1041                                 elem->mode = canon_mode(S_IFLNK);
1042
1043                         result_size = len;
1044                         result = xmallocz(len);
1045
1046                         done = read_in_full(fd, result, len);
1047                         if (done < 0)
1048                                 die_errno("read error '%s'", elem->path);
1049                         else if (done < len)
1050                                 die("early EOF '%s'", elem->path);
1051
1052                         /* If not a fake symlink, apply filters, e.g. autocrlf */
1053                         if (is_file) {
1054                                 struct strbuf buf = STRBUF_INIT;
1055
1056                                 if (convert_to_git(&the_index, elem->path, result, len, &buf, global_conv_flags_eol)) {
1057                                         free(result);
1058                                         result = strbuf_detach(&buf, &len);
1059                                         result_size = len;
1060                                 }
1061                         }
1062                 }
1063                 else {
1064                 deleted_file:
1065                         result_deleted = 1;
1066                         result_size = 0;
1067                         elem->mode = 0;
1068                         result = xcalloc(1, 1);
1069                 }
1070
1071                 if (0 <= fd)
1072                         close(fd);
1073         }
1074
1075         for (i = 0; i < num_parent; i++) {
1076                 if (elem->parent[i].mode != elem->mode) {
1077                         mode_differs = 1;
1078                         break;
1079                 }
1080         }
1081
1082         if (textconv)
1083                 is_binary = 0;
1084         else if (userdiff->binary != -1)
1085                 is_binary = userdiff->binary;
1086         else {
1087                 is_binary = buffer_is_binary(result, result_size);
1088                 for (i = 0; !is_binary && i < num_parent; i++) {
1089                         char *buf;
1090                         unsigned long size;
1091                         buf = grab_blob(&elem->parent[i].oid,
1092                                         elem->parent[i].mode,
1093                                         &size, NULL, NULL);
1094                         if (buffer_is_binary(buf, size))
1095                                 is_binary = 1;
1096                         free(buf);
1097                 }
1098         }
1099         if (is_binary) {
1100                 show_combined_header(elem, num_parent, dense, rev,
1101                                      line_prefix, mode_differs, 0);
1102                 printf("Binary files differ\n");
1103                 free(result);
1104                 return;
1105         }
1106
1107         for (cnt = 0, cp = result; cp < result + result_size; cp++) {
1108                 if (*cp == '\n')
1109                         cnt++;
1110         }
1111         if (result_size && result[result_size-1] != '\n')
1112                 cnt++; /* incomplete line */
1113
1114         sline = xcalloc(st_add(cnt, 2), sizeof(*sline));
1115         sline[0].bol = result;
1116         for (lno = 0, cp = result; cp < result + result_size; cp++) {
1117                 if (*cp == '\n') {
1118                         sline[lno].len = cp - sline[lno].bol;
1119                         lno++;
1120                         if (lno < cnt)
1121                                 sline[lno].bol = cp + 1;
1122                 }
1123         }
1124         if (result_size && result[result_size-1] != '\n')
1125                 sline[cnt-1].len = result_size - (sline[cnt-1].bol - result);
1126
1127         result_file.ptr = result;
1128         result_file.size = result_size;
1129
1130         /* Even p_lno[cnt+1] is valid -- that is for the end line number
1131          * for deletion hunk at the end.
1132          */
1133         sline[0].p_lno = xcalloc(st_mult(st_add(cnt, 2), num_parent), sizeof(unsigned long));
1134         for (lno = 0; lno <= cnt; lno++)
1135                 sline[lno+1].p_lno = sline[lno].p_lno + num_parent;
1136
1137         for (i = 0; i < num_parent; i++) {
1138                 int j;
1139                 for (j = 0; j < i; j++) {
1140                         if (!oidcmp(&elem->parent[i].oid,
1141                                      &elem->parent[j].oid)) {
1142                                 reuse_combine_diff(sline, cnt, i, j);
1143                                 break;
1144                         }
1145                 }
1146                 if (i <= j)
1147                         combine_diff(&elem->parent[i].oid,
1148                                      elem->parent[i].mode,
1149                                      &result_file, sline,
1150                                      cnt, i, num_parent, result_deleted,
1151                                      textconv, elem->path, opt->xdl_opts);
1152         }
1153
1154         show_hunks = make_hunks(sline, cnt, num_parent, dense);
1155
1156         if (show_hunks || mode_differs || working_tree_file) {
1157                 show_combined_header(elem, num_parent, dense, rev,
1158                                      line_prefix, mode_differs, 1);
1159                 dump_sline(sline, line_prefix, cnt, num_parent,
1160                            opt->use_color, result_deleted);
1161         }
1162         free(result);
1163
1164         for (lno = 0; lno < cnt; lno++) {
1165                 if (sline[lno].lost) {
1166                         struct lline *ll = sline[lno].lost;
1167                         while (ll) {
1168                                 struct lline *tmp = ll;
1169                                 ll = ll->next;
1170                                 free(tmp);
1171                         }
1172                 }
1173         }
1174         free(sline[0].p_lno);
1175         free(sline);
1176 }
1177
1178 static void show_raw_diff(struct combine_diff_path *p, int num_parent, struct rev_info *rev)
1179 {
1180         struct diff_options *opt = &rev->diffopt;
1181         int line_termination, inter_name_termination, i;
1182         const char *line_prefix = diff_line_prefix(opt);
1183
1184         line_termination = opt->line_termination;
1185         inter_name_termination = '\t';
1186         if (!line_termination)
1187                 inter_name_termination = 0;
1188
1189         if (rev->loginfo && !rev->no_commit_id)
1190                 show_log(rev);
1191
1192
1193         if (opt->output_format & DIFF_FORMAT_RAW) {
1194                 printf("%s", line_prefix);
1195
1196                 /* As many colons as there are parents */
1197                 for (i = 0; i < num_parent; i++)
1198                         putchar(':');
1199
1200                 /* Show the modes */
1201                 for (i = 0; i < num_parent; i++)
1202                         printf("%06o ", p->parent[i].mode);
1203                 printf("%06o", p->mode);
1204
1205                 /* Show sha1's */
1206                 for (i = 0; i < num_parent; i++)
1207                         printf(" %s", diff_aligned_abbrev(&p->parent[i].oid,
1208                                                           opt->abbrev));
1209                 printf(" %s ", diff_aligned_abbrev(&p->oid, opt->abbrev));
1210         }
1211
1212         if (opt->output_format & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS)) {
1213                 for (i = 0; i < num_parent; i++)
1214                         putchar(p->parent[i].status);
1215                 putchar(inter_name_termination);
1216         }
1217
1218         write_name_quoted(p->path, stdout, line_termination);
1219 }
1220
1221 /*
1222  * The result (p->elem) is from the working tree and their
1223  * parents are typically from multiple stages during a merge
1224  * (i.e. diff-files) or the state in HEAD and in the index
1225  * (i.e. diff-index).
1226  */
1227 void show_combined_diff(struct combine_diff_path *p,
1228                        int num_parent,
1229                        int dense,
1230                        struct rev_info *rev)
1231 {
1232         struct diff_options *opt = &rev->diffopt;
1233
1234         if (opt->output_format & (DIFF_FORMAT_RAW |
1235                                   DIFF_FORMAT_NAME |
1236                                   DIFF_FORMAT_NAME_STATUS))
1237                 show_raw_diff(p, num_parent, rev);
1238         else if (opt->output_format & DIFF_FORMAT_PATCH)
1239                 show_patch_diff(p, num_parent, dense, 1, rev);
1240 }
1241
1242 static void free_combined_pair(struct diff_filepair *pair)
1243 {
1244         free(pair->two);
1245         free(pair);
1246 }
1247
1248 /*
1249  * A combine_diff_path expresses N parents on the LHS against 1 merge
1250  * result. Synthesize a diff_filepair that has N entries on the "one"
1251  * side and 1 entry on the "two" side.
1252  *
1253  * In the future, we might want to add more data to combine_diff_path
1254  * so that we can fill fields we are ignoring (most notably, size) here,
1255  * but currently nobody uses it, so this should suffice for now.
1256  */
1257 static struct diff_filepair *combined_pair(struct combine_diff_path *p,
1258                                            int num_parent)
1259 {
1260         int i;
1261         struct diff_filepair *pair;
1262         struct diff_filespec *pool;
1263
1264         pair = xmalloc(sizeof(*pair));
1265         pool = xcalloc(st_add(num_parent, 1), sizeof(struct diff_filespec));
1266         pair->one = pool + 1;
1267         pair->two = pool;
1268
1269         for (i = 0; i < num_parent; i++) {
1270                 pair->one[i].path = p->path;
1271                 pair->one[i].mode = p->parent[i].mode;
1272                 oidcpy(&pair->one[i].oid, &p->parent[i].oid);
1273                 pair->one[i].oid_valid = !is_null_oid(&p->parent[i].oid);
1274                 pair->one[i].has_more_entries = 1;
1275         }
1276         pair->one[num_parent - 1].has_more_entries = 0;
1277
1278         pair->two->path = p->path;
1279         pair->two->mode = p->mode;
1280         oidcpy(&pair->two->oid, &p->oid);
1281         pair->two->oid_valid = !is_null_oid(&p->oid);
1282         return pair;
1283 }
1284
1285 static void handle_combined_callback(struct diff_options *opt,
1286                                      struct combine_diff_path *paths,
1287                                      int num_parent,
1288                                      int num_paths)
1289 {
1290         struct combine_diff_path *p;
1291         struct diff_queue_struct q;
1292         int i;
1293
1294         q.queue = xcalloc(num_paths, sizeof(struct diff_filepair *));
1295         q.alloc = num_paths;
1296         q.nr = num_paths;
1297         for (i = 0, p = paths; p; p = p->next)
1298                 q.queue[i++] = combined_pair(p, num_parent);
1299         opt->format_callback(&q, opt, opt->format_callback_data);
1300         for (i = 0; i < num_paths; i++)
1301                 free_combined_pair(q.queue[i]);
1302         free(q.queue);
1303 }
1304
1305 static const char *path_path(void *obj)
1306 {
1307         struct combine_diff_path *path = (struct combine_diff_path *)obj;
1308
1309         return path->path;
1310 }
1311
1312
1313 /* find set of paths that every parent touches */
1314 static struct combine_diff_path *find_paths_generic(const struct object_id *oid,
1315         const struct oid_array *parents, struct diff_options *opt)
1316 {
1317         struct combine_diff_path *paths = NULL;
1318         int i, num_parent = parents->nr;
1319
1320         int output_format = opt->output_format;
1321         const char *orderfile = opt->orderfile;
1322
1323         opt->output_format = DIFF_FORMAT_NO_OUTPUT;
1324         /* tell diff_tree to emit paths in sorted (=tree) order */
1325         opt->orderfile = NULL;
1326
1327         /* D(A,P1...Pn) = D(A,P1) ^ ... ^ D(A,Pn)  (wrt paths) */
1328         for (i = 0; i < num_parent; i++) {
1329                 /*
1330                  * show stat against the first parent even when doing
1331                  * combined diff.
1332                  */
1333                 int stat_opt = (output_format &
1334                                 (DIFF_FORMAT_NUMSTAT|DIFF_FORMAT_DIFFSTAT));
1335                 if (i == 0 && stat_opt)
1336                         opt->output_format = stat_opt;
1337                 else
1338                         opt->output_format = DIFF_FORMAT_NO_OUTPUT;
1339                 diff_tree_oid(&parents->oid[i], oid, "", opt);
1340                 diffcore_std(opt);
1341                 paths = intersect_paths(paths, i, num_parent);
1342
1343                 /* if showing diff, show it in requested order */
1344                 if (opt->output_format != DIFF_FORMAT_NO_OUTPUT &&
1345                     orderfile) {
1346                         diffcore_order(orderfile);
1347                 }
1348
1349                 diff_flush(opt);
1350         }
1351
1352         opt->output_format = output_format;
1353         opt->orderfile = orderfile;
1354         return paths;
1355 }
1356
1357
1358 /*
1359  * find set of paths that everybody touches, assuming diff is run without
1360  * rename/copy detection, etc, comparing all trees simultaneously (= faster).
1361  */
1362 static struct combine_diff_path *find_paths_multitree(
1363         const struct object_id *oid, const struct oid_array *parents,
1364         struct diff_options *opt)
1365 {
1366         int i, nparent = parents->nr;
1367         const struct object_id **parents_oid;
1368         struct combine_diff_path paths_head;
1369         struct strbuf base;
1370
1371         ALLOC_ARRAY(parents_oid, nparent);
1372         for (i = 0; i < nparent; i++)
1373                 parents_oid[i] = &parents->oid[i];
1374
1375         /* fake list head, so worker can assume it is non-NULL */
1376         paths_head.next = NULL;
1377
1378         strbuf_init(&base, PATH_MAX);
1379         diff_tree_paths(&paths_head, oid, parents_oid, nparent, &base, opt);
1380
1381         strbuf_release(&base);
1382         free(parents_oid);
1383         return paths_head.next;
1384 }
1385
1386
1387 void diff_tree_combined(const struct object_id *oid,
1388                         const struct oid_array *parents,
1389                         int dense,
1390                         struct rev_info *rev)
1391 {
1392         struct diff_options *opt = &rev->diffopt;
1393         struct diff_options diffopts;
1394         struct combine_diff_path *p, *paths;
1395         int i, num_paths, needsep, show_log_first, num_parent = parents->nr;
1396         int need_generic_pathscan;
1397
1398         /* nothing to do, if no parents */
1399         if (!num_parent)
1400                 return;
1401
1402         show_log_first = !!rev->loginfo && !rev->no_commit_id;
1403         needsep = 0;
1404         if (show_log_first) {
1405                 show_log(rev);
1406
1407                 if (rev->verbose_header && opt->output_format &&
1408                     opt->output_format != DIFF_FORMAT_NO_OUTPUT &&
1409                     !commit_format_is_empty(rev->commit_format))
1410                         printf("%s%c", diff_line_prefix(opt),
1411                                opt->line_termination);
1412         }
1413
1414         diffopts = *opt;
1415         copy_pathspec(&diffopts.pathspec, &opt->pathspec);
1416         diffopts.flags.recursive = 1;
1417         diffopts.flags.allow_external = 0;
1418
1419         /* find set of paths that everybody touches
1420          *
1421          * NOTE
1422          *
1423          * Diffcore transformations are bound to diff_filespec and logic
1424          * comparing two entries - i.e. they do not apply directly to combine
1425          * diff.
1426          *
1427          * If some of such transformations is requested - we launch generic
1428          * path scanning, which works significantly slower compared to
1429          * simultaneous all-trees-in-one-go scan in find_paths_multitree().
1430          *
1431          * TODO some of the filters could be ported to work on
1432          * combine_diff_paths - i.e. all functionality that skips paths, so in
1433          * theory, we could end up having only multitree path scanning.
1434          *
1435          * NOTE please keep this semantically in sync with diffcore_std()
1436          */
1437         need_generic_pathscan = opt->skip_stat_unmatch  ||
1438                         opt->flags.follow_renames       ||
1439                         opt->break_opt != -1    ||
1440                         opt->detect_rename      ||
1441                         (opt->pickaxe_opts & DIFF_PICKAXE_KINDS_MASK)   ||
1442                         opt->filter;
1443
1444
1445         if (need_generic_pathscan) {
1446                 /*
1447                  * NOTE generic case also handles --stat, as it computes
1448                  * diff(sha1,parent_i) for all i to do the job, specifically
1449                  * for parent0.
1450                  */
1451                 paths = find_paths_generic(oid, parents, &diffopts);
1452         }
1453         else {
1454                 int stat_opt;
1455                 paths = find_paths_multitree(oid, parents, &diffopts);
1456
1457                 /*
1458                  * show stat against the first parent even
1459                  * when doing combined diff.
1460                  */
1461                 stat_opt = (opt->output_format &
1462                                 (DIFF_FORMAT_NUMSTAT|DIFF_FORMAT_DIFFSTAT));
1463                 if (stat_opt) {
1464                         diffopts.output_format = stat_opt;
1465
1466                         diff_tree_oid(&parents->oid[0], oid, "", &diffopts);
1467                         diffcore_std(&diffopts);
1468                         if (opt->orderfile)
1469                                 diffcore_order(opt->orderfile);
1470                         diff_flush(&diffopts);
1471                 }
1472         }
1473
1474         /* find out number of surviving paths */
1475         for (num_paths = 0, p = paths; p; p = p->next)
1476                 num_paths++;
1477
1478         /* order paths according to diffcore_order */
1479         if (opt->orderfile && num_paths) {
1480                 struct obj_order *o;
1481
1482                 ALLOC_ARRAY(o, num_paths);
1483                 for (i = 0, p = paths; p; p = p->next, i++)
1484                         o[i].obj = p;
1485                 order_objects(opt->orderfile, path_path, o, num_paths);
1486                 for (i = 0; i < num_paths - 1; i++) {
1487                         p = o[i].obj;
1488                         p->next = o[i+1].obj;
1489                 }
1490
1491                 p = o[num_paths-1].obj;
1492                 p->next = NULL;
1493                 paths = o[0].obj;
1494                 free(o);
1495         }
1496
1497
1498         if (num_paths) {
1499                 if (opt->output_format & (DIFF_FORMAT_RAW |
1500                                           DIFF_FORMAT_NAME |
1501                                           DIFF_FORMAT_NAME_STATUS)) {
1502                         for (p = paths; p; p = p->next)
1503                                 show_raw_diff(p, num_parent, rev);
1504                         needsep = 1;
1505                 }
1506                 else if (opt->output_format &
1507                          (DIFF_FORMAT_NUMSTAT|DIFF_FORMAT_DIFFSTAT))
1508                         needsep = 1;
1509                 else if (opt->output_format & DIFF_FORMAT_CALLBACK)
1510                         handle_combined_callback(opt, paths, num_parent, num_paths);
1511
1512                 if (opt->output_format & DIFF_FORMAT_PATCH) {
1513                         if (needsep)
1514                                 printf("%s%c", diff_line_prefix(opt),
1515                                        opt->line_termination);
1516                         for (p = paths; p; p = p->next)
1517                                 show_patch_diff(p, num_parent, dense,
1518                                                 0, rev);
1519                 }
1520         }
1521
1522         /* Clean things up */
1523         while (paths) {
1524                 struct combine_diff_path *tmp = paths;
1525                 paths = paths->next;
1526                 free(tmp);
1527         }
1528
1529         clear_pathspec(&diffopts.pathspec);
1530 }
1531
1532 void diff_tree_combined_merge(const struct commit *commit, int dense,
1533                               struct rev_info *rev)
1534 {
1535         struct commit_list *parent = get_saved_parents(rev, commit);
1536         struct oid_array parents = OID_ARRAY_INIT;
1537
1538         while (parent) {
1539                 oid_array_append(&parents, &parent->item->object.oid);
1540                 parent = parent->next;
1541         }
1542         diff_tree_combined(&commit->object.oid, &parents, dense, rev);
1543         oid_array_clear(&parents);
1544 }