git.oblomov.eu Git - git/blob - combine-diff.c

   1 #include "cache.h"
   2 #include "object-store.h"
   3 #include "commit.h"
   4 #include "blob.h"
   5 #include "diff.h"
   6 #include "diffcore.h"
   7 #include "quote.h"
   8 #include "xdiff-interface.h"
   9 #include "xdiff/xmacros.h"
  10 #include "log-tree.h"
  11 #include "refs.h"
  12 #include "userdiff.h"
  13 #include "sha1-array.h"
  14 #include "revision.h"
  15
  16 static int compare_paths(const struct combine_diff_path *one,
  17                           const struct diff_filespec *two)
  18 {
  19         if (!S_ISDIR(one->mode) && !S_ISDIR(two->mode))
  20                 return strcmp(one->path, two->path);
  21
  22         return base_name_compare(one->path, strlen(one->path), one->mode,
  23                                  two->path, strlen(two->path), two->mode);
  24 }
  25
  26 static struct combine_diff_path *intersect_paths(struct combine_diff_path *curr, int n, int num_parent)
  27 {
  28         struct diff_queue_struct *q = &diff_queued_diff;
  29         struct combine_diff_path *p, **tail = &curr;
  30         int i, cmp;
  31
  32         if (!n) {
  33                 for (i = 0; i < q->nr; i++) {
  34                         int len;
  35                         const char *path;
  36                         if (diff_unmodified_pair(q->queue[i]))
  37                                 continue;
  38                         path = q->queue[i]->two->path;
  39                         len = strlen(path);
  40                         p = xmalloc(combine_diff_path_size(num_parent, len));
  41                         p->path = (char *) &(p->parent[num_parent]);
  42                         memcpy(p->path, path, len);
  43                         p->path[len] = 0;
  44                         p->next = NULL;
  45                         memset(p->parent, 0,
  46                                sizeof(p->parent[0]) * num_parent);
  47
  48                         oidcpy(&p->oid, &q->queue[i]->two->oid);
  49                         p->mode = q->queue[i]->two->mode;
  50                         oidcpy(&p->parent[n].oid, &q->queue[i]->one->oid);
  51                         p->parent[n].mode = q->queue[i]->one->mode;
  52                         p->parent[n].status = q->queue[i]->status;
  53                         *tail = p;
  54                         tail = &p->next;
  55                 }
  56                 return curr;
  57         }
  58
  59         /*
  60          * paths in curr (linked list) and q->queue[] (array) are
  61          * both sorted in the tree order.
  62          */
  63         i = 0;
  64         while ((p = *tail) != NULL) {
  65                 cmp = ((i >= q->nr)
  66                        ? -1 : compare_paths(p, q->queue[i]->two));
  67
  68                 if (cmp < 0) {
  69                         /* p->path not in q->queue[]; drop it */
  70                         *tail = p->next;
  71                         free(p);
  72                         continue;
  73                 }
  74
  75                 if (cmp > 0) {
  76                         /* q->queue[i] not in p->path; skip it */
  77                         i++;
  78                         continue;
  79                 }
  80
  81                 oidcpy(&p->parent[n].oid, &q->queue[i]->one->oid);
  82                 p->parent[n].mode = q->queue[i]->one->mode;
  83                 p->parent[n].status = q->queue[i]->status;
  84
  85                 tail = &p->next;
  86                 i++;
  87         }
  88         return curr;
  89 }
  90
  91 /* Lines lost from parent */
  92 struct lline {
  93         struct lline *next, *prev;
  94         int len;
  95         unsigned long parent_map;
  96         char line[FLEX_ARRAY];
  97 };
  98
  99 /* Lines lost from current parent (before coalescing) */
 100 struct plost {
 101         struct lline *lost_head, *lost_tail;
 102         int len;
 103 };
 104
 105 /* Lines surviving in the merge result */
 106 struct sline {
 107         /* Accumulated and coalesced lost lines */
 108         struct lline *lost;
 109         int lenlost;
 110         struct plost plost;
 111         char *bol;
 112         int len;
 113         /* bit 0 up to (N-1) are on if the parent has this line (i.e.
 114          * we did not change it).
 115          * bit N is used for "interesting" lines, including context.
 116          * bit (N+1) is used for "do not show deletion before this".
 117          */
 118         unsigned long flag;
 119         unsigned long *p_lno;
 120 };
 121
 122 static int match_string_spaces(const char *line1, int len1,
 123                                const char *line2, int len2,
 124                                long flags)
 125 {
 126         if (flags & XDF_WHITESPACE_FLAGS) {
 127                 for (; len1 > 0 && XDL_ISSPACE(line1[len1 - 1]); len1--);
 128                 for (; len2 > 0 && XDL_ISSPACE(line2[len2 - 1]); len2--);
 129         }
 130
 131         if (!(flags & (XDF_IGNORE_WHITESPACE | XDF_IGNORE_WHITESPACE_CHANGE)))
 132                 return (len1 == len2 && !memcmp(line1, line2, len1));
 133
 134         while (len1 > 0 && len2 > 0) {
 135                 len1--;
 136                 len2--;
 137                 if (XDL_ISSPACE(line1[len1]) || XDL_ISSPACE(line2[len2])) {
 138                         if ((flags & XDF_IGNORE_WHITESPACE_CHANGE) &&
 139                             (!XDL_ISSPACE(line1[len1]) || !XDL_ISSPACE(line2[len2])))
 140                                 return 0;
 141
 142                         for (; len1 > 0 && XDL_ISSPACE(line1[len1]); len1--);
 143                         for (; len2 > 0 && XDL_ISSPACE(line2[len2]); len2--);
 144                 }
 145                 if (line1[len1] != line2[len2])
 146                         return 0;
 147         }
 148
 149         if (flags & XDF_IGNORE_WHITESPACE) {
 150                 /* Consume remaining spaces */
 151                 for (; len1 > 0 && XDL_ISSPACE(line1[len1 - 1]); len1--);
 152                 for (; len2 > 0 && XDL_ISSPACE(line2[len2 - 1]); len2--);
 153         }
 154
 155         /* We matched full line1 and line2 */
 156         if (!len1 && !len2)
 157                 return 1;
 158
 159         return 0;
 160 }
 161
 162 enum coalesce_direction { MATCH, BASE, NEW };
 163
 164 /* Coalesce new lines into base by finding LCS */
 165 static struct lline *coalesce_lines(struct lline *base, int *lenbase,
 166                                     struct lline *newline, int lennew,
 167                                     unsigned long parent, long flags)
 168 {
 169         int **lcs;
 170         enum coalesce_direction **directions;
 171         struct lline *baseend, *newend = NULL;
 172         int i, j, origbaselen = *lenbase;
 173
 174         if (newline == NULL)
 175                 return base;
 176
 177         if (base == NULL) {
 178                 *lenbase = lennew;
 179                 return newline;
 180         }
 181
 182         /*
 183          * Coalesce new lines into base by finding the LCS
 184          * - Create the table to run dynamic programming
 185          * - Compute the LCS
 186          * - Then reverse read the direction structure:
 187          *   - If we have MATCH, assign parent to base flag, and consume
 188          *   both baseend and newend
 189          *   - Else if we have BASE, consume baseend
 190          *   - Else if we have NEW, insert newend lline into base and
 191          *   consume newend
 192          */
 193         lcs = xcalloc(st_add(origbaselen, 1), sizeof(int*));
 194         directions = xcalloc(st_add(origbaselen, 1), sizeof(enum coalesce_direction*));
 195         for (i = 0; i < origbaselen + 1; i++) {
 196                 lcs[i] = xcalloc(st_add(lennew, 1), sizeof(int));
 197                 directions[i] = xcalloc(st_add(lennew, 1), sizeof(enum coalesce_direction));
 198                 directions[i][0] = BASE;
 199         }
 200         for (j = 1; j < lennew + 1; j++)
 201                 directions[0][j] = NEW;
 202
 203         for (i = 1, baseend = base; i < origbaselen + 1; i++) {
 204                 for (j = 1, newend = newline; j < lennew + 1; j++) {
 205                         if (match_string_spaces(baseend->line, baseend->len,
 206                                                 newend->line, newend->len, flags)) {
 207                                 lcs[i][j] = lcs[i - 1][j - 1] + 1;
 208                                 directions[i][j] = MATCH;
 209                         } else if (lcs[i][j - 1] >= lcs[i - 1][j]) {
 210                                 lcs[i][j] = lcs[i][j - 1];
 211                                 directions[i][j] = NEW;
 212                         } else {
 213                                 lcs[i][j] = lcs[i - 1][j];
 214                                 directions[i][j] = BASE;
 215                         }
 216                         if (newend->next)
 217                                 newend = newend->next;
 218                 }
 219                 if (baseend->next)
 220                         baseend = baseend->next;
 221         }
 222
 223         for (i = 0; i < origbaselen + 1; i++)
 224                 free(lcs[i]);
 225         free(lcs);
 226
 227         /* At this point, baseend and newend point to the end of each lists */
 228         i--;
 229         j--;
 230         while (i != 0 || j != 0) {
 231                 if (directions[i][j] == MATCH) {
 232                         baseend->parent_map |= 1<<parent;
 233                         baseend = baseend->prev;
 234                         newend = newend->prev;
 235                         i--;
 236                         j--;
 237                 } else if (directions[i][j] == NEW) {
 238                         struct lline *lline;
 239
 240                         lline = newend;
 241                         /* Remove lline from new list and update newend */
 242                         if (lline->prev)
 243                                 lline->prev->next = lline->next;
 244                         else
 245                                 newline = lline->next;
 246                         if (lline->next)
 247                                 lline->next->prev = lline->prev;
 248
 249                         newend = lline->prev;
 250                         j--;
 251
 252                         /* Add lline to base list */
 253                         if (baseend) {
 254                                 lline->next = baseend->next;
 255                                 lline->prev = baseend;
 256                                 if (lline->prev)
 257                                         lline->prev->next = lline;
 258                         }
 259                         else {
 260                                 lline->next = base;
 261                                 base = lline;
 262                         }
 263                         (*lenbase)++;
 264
 265                         if (lline->next)
 266                                 lline->next->prev = lline;
 267
 268                 } else {
 269                         baseend = baseend->prev;
 270                         i--;
 271                 }
 272         }
 273
 274         newend = newline;
 275         while (newend) {
 276                 struct lline *lline = newend;
 277                 newend = newend->next;
 278                 free(lline);
 279         }
 280
 281         for (i = 0; i < origbaselen + 1; i++)
 282                 free(directions[i]);
 283         free(directions);
 284
 285         return base;
 286 }
 287
 288 static char *grab_blob(struct repository *r,
 289                        const struct object_id *oid, unsigned int mode,
 290                        unsigned long *size, struct userdiff_driver *textconv,
 291                        const char *path)
 292 {
 293         char *blob;
 294         enum object_type type;
 295
 296         if (S_ISGITLINK(mode)) {
 297                 struct strbuf buf = STRBUF_INIT;
 298                 strbuf_addf(&buf, "Subproject commit %s\n", oid_to_hex(oid));
 299                 *size = buf.len;
 300                 blob = strbuf_detach(&buf, NULL);
 301         } else if (is_null_oid(oid)) {
 302                 /* deleted blob */
 303                 *size = 0;
 304                 return xcalloc(1, 1);
 305         } else if (textconv) {
 306                 struct diff_filespec *df = alloc_filespec(path);
 307                 fill_filespec(df, oid, 1, mode);
 308                 *size = fill_textconv(r, textconv, df, &blob);
 309                 free_filespec(df);
 310         } else {
 311                 blob = read_object_file(oid, &type, size);
 312                 if (type != OBJ_BLOB)
 313                         die("object '%s' is not a blob!", oid_to_hex(oid));
 314         }
 315         return blob;
 316 }
 317
 318 static void append_lost(struct sline *sline, int n, const char *line, int len)
 319 {
 320         struct lline *lline;
 321         unsigned long this_mask = (1UL<<n);
 322         if (line[len-1] == '\n')
 323                 len--;
 324
 325         FLEX_ALLOC_MEM(lline, line, line, len);
 326         lline->len = len;
 327         lline->next = NULL;
 328         lline->prev = sline->plost.lost_tail;
 329         if (lline->prev)
 330                 lline->prev->next = lline;
 331         else
 332                 sline->plost.lost_head = lline;
 333         sline->plost.lost_tail = lline;
 334         sline->plost.len++;
 335         lline->parent_map = this_mask;
 336 }
 337
 338 struct combine_diff_state {
 339         unsigned int lno;
 340         int ob, on, nb, nn;
 341         unsigned long nmask;
 342         int num_parent;
 343         int n;
 344         struct sline *sline;
 345         struct sline *lost_bucket;
 346 };
 347
 348 static void consume_line(void *state_, char *line, unsigned long len)
 349 {
 350         struct combine_diff_state *state = state_;
 351         if (5 < len && !memcmp("@@ -", line, 4)) {
 352                 if (parse_hunk_header(line, len,
 353                                       &state->ob, &state->on,
 354                                       &state->nb, &state->nn))
 355                         return;
 356                 state->lno = state->nb;
 357                 if (state->nn == 0) {
 358                         /* @@ -X,Y +N,0 @@ removed Y lines
 359                          * that would have come *after* line N
 360                          * in the result.  Our lost buckets hang
 361                          * to the line after the removed lines,
 362                          *
 363                          * Note that this is correct even when N == 0,
 364                          * in which case the hunk removes the first
 365                          * line in the file.
 366                          */
 367                         state->lost_bucket = &state->sline[state->nb];
 368                         if (!state->nb)
 369                                 state->nb = 1;
 370                 } else {
 371                         state->lost_bucket = &state->sline[state->nb-1];
 372                 }
 373                 if (!state->sline[state->nb-1].p_lno)
 374                         state->sline[state->nb-1].p_lno =
 375                                 xcalloc(state->num_parent,
 376                                         sizeof(unsigned long));
 377                 state->sline[state->nb-1].p_lno[state->n] = state->ob;
 378                 return;
 379         }
 380         if (!state->lost_bucket)
 381                 return; /* not in any hunk yet */
 382         switch (line[0]) {
 383         case '-':
 384                 append_lost(state->lost_bucket, state->n, line+1, len-1);
 385                 break;
 386         case '+':
 387                 state->sline[state->lno-1].flag |= state->nmask;
 388                 state->lno++;
 389                 break;
 390         }
 391 }
 392
 393 static void combine_diff(struct repository *r,
 394                          const struct object_id *parent, unsigned int mode,
 395                          mmfile_t *result_file,
 396                          struct sline *sline, unsigned int cnt, int n,
 397                          int num_parent, int result_deleted,
 398                          struct userdiff_driver *textconv,
 399                          const char *path, long flags)
 400 {
 401         unsigned int p_lno, lno;
 402         unsigned long nmask = (1UL << n);
 403         xpparam_t xpp;
 404         xdemitconf_t xecfg;
 405         mmfile_t parent_file;
 406         struct combine_diff_state state;
 407         unsigned long sz;
 408
 409         if (result_deleted)
 410                 return; /* result deleted */
 411
 412         parent_file.ptr = grab_blob(r, parent, mode, &sz, textconv, path);
 413         parent_file.size = sz;
 414         memset(&xpp, 0, sizeof(xpp));
 415         xpp.flags = flags;
 416         memset(&xecfg, 0, sizeof(xecfg));
 417         memset(&state, 0, sizeof(state));
 418         state.nmask = nmask;
 419         state.sline = sline;
 420         state.lno = 1;
 421         state.num_parent = num_parent;
 422         state.n = n;
 423
 424         if (xdi_diff_outf(&parent_file, result_file, consume_line, &state,
 425                           &xpp, &xecfg))
 426                 die("unable to generate combined diff for %s",
 427                     oid_to_hex(parent));
 428         free(parent_file.ptr);
 429
 430         /* Assign line numbers for this parent.
 431          *
 432          * sline[lno].p_lno[n] records the first line number
 433          * (counting from 1) for parent N if the final hunk display
 434          * started by showing sline[lno] (possibly showing the lost
 435          * lines attached to it first).
 436          */
 437         for (lno = 0,  p_lno = 1; lno <= cnt; lno++) {
 438                 struct lline *ll;
 439                 sline[lno].p_lno[n] = p_lno;
 440
 441                 /* Coalesce new lines */
 442                 if (sline[lno].plost.lost_head) {
 443                         struct sline *sl = &sline[lno];
 444                         sl->lost = coalesce_lines(sl->lost, &sl->lenlost,
 445                                                   sl->plost.lost_head,
 446                                                   sl->plost.len, n, flags);
 447                         sl->plost.lost_head = sl->plost.lost_tail = NULL;
 448                         sl->plost.len = 0;
 449                 }
 450
 451                 /* How many lines would this sline advance the p_lno? */
 452                 ll = sline[lno].lost;
 453                 while (ll) {
 454                         if (ll->parent_map & nmask)
 455                                 p_lno++; /* '-' means parent had it */
 456                         ll = ll->next;
 457                 }
 458                 if (lno < cnt && !(sline[lno].flag & nmask))
 459                         p_lno++; /* no '+' means parent had it */
 460         }
 461         sline[lno].p_lno[n] = p_lno; /* trailer */
 462 }
 463
 464 static unsigned long context = 3;
 465 static char combine_marker = '@';
 466
 467 static int interesting(struct sline *sline, unsigned long all_mask)
 468 {
 469         /* If some parents lost lines here, or if we have added to
 470          * some parent, it is interesting.
 471          */
 472         return ((sline->flag & all_mask) || sline->lost);
 473 }
 474
 475 static unsigned long adjust_hunk_tail(struct sline *sline,
 476                                       unsigned long all_mask,
 477                                       unsigned long hunk_begin,
 478                                       unsigned long i)
 479 {
 480         /* i points at the first uninteresting line.  If the last line
 481          * of the hunk was interesting only because it has some
 482          * deletion, then it is not all that interesting for the
 483          * purpose of giving trailing context lines.  This is because
 484          * we output '-' line and then unmodified sline[i-1] itself in
 485          * that case which gives us one extra context line.
 486          */
 487         if ((hunk_begin + 1 <= i) && !(sline[i-1].flag & all_mask))
 488                 i--;
 489         return i;
 490 }
 491
 492 static unsigned long find_next(struct sline *sline,
 493                                unsigned long mark,
 494                                unsigned long i,
 495                                unsigned long cnt,
 496                                int look_for_uninteresting)
 497 {
 498         /* We have examined up to i-1 and are about to look at i.
 499          * Find next interesting or uninteresting line.  Here,
 500          * "interesting" does not mean interesting(), but marked by
 501          * the give_context() function below (i.e. it includes context
 502          * lines that are not interesting to interesting() function
 503          * that are surrounded by interesting() ones.
 504          */
 505         while (i <= cnt)
 506                 if (look_for_uninteresting
 507                     ? !(sline[i].flag & mark)
 508                     : (sline[i].flag & mark))
 509                         return i;
 510                 else
 511                         i++;
 512         return i;
 513 }
 514
 515 static int give_context(struct sline *sline, unsigned long cnt, int num_parent)
 516 {
 517         unsigned long all_mask = (1UL<<num_parent) - 1;
 518         unsigned long mark = (1UL<<num_parent);
 519         unsigned long no_pre_delete = (2UL<<num_parent);
 520         unsigned long i;
 521
 522         /* Two groups of interesting lines may have a short gap of
 523          * uninteresting lines.  Connect such groups to give them a
 524          * bit of context.
 525          *
 526          * We first start from what the interesting() function says,
 527          * and mark them with "mark", and paint context lines with the
 528          * mark.  So interesting() would still say false for such context
 529          * lines but they are treated as "interesting" in the end.
 530          */
 531         i = find_next(sline, mark, 0, cnt, 0);
 532         if (cnt < i)
 533                 return 0;
 534
 535         while (i <= cnt) {
 536                 unsigned long j = (context < i) ? (i - context) : 0;
 537                 unsigned long k;
 538
 539                 /* Paint a few lines before the first interesting line. */
 540                 while (j < i) {
 541                         if (!(sline[j].flag & mark))
 542                                 sline[j].flag |= no_pre_delete;
 543                         sline[j++].flag |= mark;
 544                 }
 545
 546         again:
 547                 /* we know up to i is to be included.  where does the
 548                  * next uninteresting one start?
 549                  */
 550                 j = find_next(sline, mark, i, cnt, 1);
 551                 if (cnt < j)
 552                         break; /* the rest are all interesting */
 553
 554                 /* lookahead context lines */
 555                 k = find_next(sline, mark, j, cnt, 0);
 556                 j = adjust_hunk_tail(sline, all_mask, i, j);
 557
 558                 if (k < j + context) {
 559                         /* k is interesting and [j,k) are not, but
 560                          * paint them interesting because the gap is small.
 561                          */
 562                         while (j < k)
 563                                 sline[j++].flag |= mark;
 564                         i = k;
 565                         goto again;
 566                 }
 567
 568                 /* j is the first uninteresting line and there is
 569                  * no overlap beyond it within context lines.  Paint
 570                  * the trailing edge a bit.
 571                  */
 572                 i = k;
 573                 k = (j + context < cnt+1) ? j + context : cnt+1;
 574                 while (j < k)
 575                         sline[j++].flag |= mark;
 576         }
 577         return 1;
 578 }
 579
 580 static int make_hunks(struct sline *sline, unsigned long cnt,
 581                        int num_parent, int dense)
 582 {
 583         unsigned long all_mask = (1UL<<num_parent) - 1;
 584         unsigned long mark = (1UL<<num_parent);
 585         unsigned long i;
 586         int has_interesting = 0;
 587
 588         for (i = 0; i <= cnt; i++) {
 589                 if (interesting(&sline[i], all_mask))
 590                         sline[i].flag |= mark;
 591                 else
 592                         sline[i].flag &= ~mark;
 593         }
 594         if (!dense)
 595                 return give_context(sline, cnt, num_parent);
 596
 597         /* Look at each hunk, and if we have changes from only one
 598          * parent, or the changes are the same from all but one
 599          * parent, mark that uninteresting.
 600          */
 601         i = 0;
 602         while (i <= cnt) {
 603                 unsigned long j, hunk_begin, hunk_end;
 604                 unsigned long same_diff;
 605                 while (i <= cnt && !(sline[i].flag & mark))
 606                         i++;
 607                 if (cnt < i)
 608                         break; /* No more interesting hunks */
 609                 hunk_begin = i;
 610                 for (j = i + 1; j <= cnt; j++) {
 611                         if (!(sline[j].flag & mark)) {
 612                                 /* Look beyond the end to see if there
 613                                  * is an interesting line after this
 614                                  * hunk within context span.
 615                                  */
 616                                 unsigned long la; /* lookahead */
 617                                 int contin = 0;
 618                                 la = adjust_hunk_tail(sline, all_mask,
 619                                                      hunk_begin, j);
 620                                 la = (la + context < cnt + 1) ?
 621                                         (la + context) : cnt + 1;
 622                                 while (la && j <= --la) {
 623                                         if (sline[la].flag & mark) {
 624                                                 contin = 1;
 625                                                 break;
 626                                         }
 627                                 }
 628                                 if (!contin)
 629                                         break;
 630                                 j = la;
 631                         }
 632                 }
 633                 hunk_end = j;
 634
 635                 /* [i..hunk_end) are interesting.  Now is it really
 636                  * interesting?  We check if there are only two versions
 637                  * and the result matches one of them.  That is, we look
 638                  * at:
 639                  *   (+) line, which records lines added to which parents;
 640                  *       this line appears in the result.
 641                  *   (-) line, which records from what parents the line
 642                  *       was removed; this line does not appear in the result.
 643                  * then check the set of parents the result has difference
 644                  * from, from all lines.  If there are lines that has
 645                  * different set of parents that the result has differences
 646                  * from, that means we have more than two versions.
 647                  *
 648                  * Even when we have only two versions, if the result does
 649                  * not match any of the parents, the it should be considered
 650                  * interesting.  In such a case, we would have all '+' line.
 651                  * After passing the above "two versions" test, that would
 652                  * appear as "the same set of parents" to be "all parents".
 653                  */
 654                 same_diff = 0;
 655                 has_interesting = 0;
 656                 for (j = i; j < hunk_end && !has_interesting; j++) {
 657                         unsigned long this_diff = sline[j].flag & all_mask;
 658                         struct lline *ll = sline[j].lost;
 659                         if (this_diff) {
 660                                 /* This has some changes.  Is it the
 661                                  * same as others?
 662                                  */
 663                                 if (!same_diff)
 664                                         same_diff = this_diff;
 665                                 else if (same_diff != this_diff) {
 666                                         has_interesting = 1;
 667                                         break;
 668                                 }
 669                         }
 670                         while (ll && !has_interesting) {
 671                                 /* Lost this line from these parents;
 672                                  * who are they?  Are they the same?
 673                                  */
 674                                 this_diff = ll->parent_map;
 675                                 if (!same_diff)
 676                                         same_diff = this_diff;
 677                                 else if (same_diff != this_diff) {
 678                                         has_interesting = 1;
 679                                 }
 680                                 ll = ll->next;
 681                         }
 682                 }
 683
 684                 if (!has_interesting && same_diff != all_mask) {
 685                         /* This hunk is not that interesting after all */
 686                         for (j = hunk_begin; j < hunk_end; j++)
 687                                 sline[j].flag &= ~mark;
 688                 }
 689                 i = hunk_end;
 690         }
 691
 692         has_interesting = give_context(sline, cnt, num_parent);
 693         return has_interesting;
 694 }
 695
 696 static void show_parent_lno(struct sline *sline, unsigned long l0, unsigned long l1, int n, unsigned long null_context)
 697 {
 698         l0 = sline[l0].p_lno[n];
 699         l1 = sline[l1].p_lno[n];
 700         printf(" -%lu,%lu", l0, l1-l0-null_context);
 701 }
 702
 703 static int hunk_comment_line(const char *bol)
 704 {
 705         int ch;
 706
 707         if (!bol)
 708                 return 0;
 709         ch = *bol & 0xff;
 710         return (isalpha(ch) || ch == '_' || ch == '$');
 711 }
 712
 713 static void show_line_to_eol(const char *line, int len, const char *reset)
 714 {
 715         int saw_cr_at_eol = 0;
 716         if (len < 0)
 717                 len = strlen(line);
 718         saw_cr_at_eol = (len && line[len-1] == '\r');
 719
 720         printf("%.*s%s%s\n", len - saw_cr_at_eol, line,
 721                reset,
 722                saw_cr_at_eol ? "\r" : "");
 723 }
 724
 725 static void dump_sline(struct sline *sline, const char *line_prefix,
 726                        unsigned long cnt, int num_parent,
 727                        int use_color, int result_deleted)
 728 {
 729         unsigned long mark = (1UL<<num_parent);
 730         unsigned long no_pre_delete = (2UL<<num_parent);
 731         int i;
 732         unsigned long lno = 0;
 733         const char *c_frag = diff_get_color(use_color, DIFF_FRAGINFO);
 734         const char *c_func = diff_get_color(use_color, DIFF_FUNCINFO);
 735         const char *c_new = diff_get_color(use_color, DIFF_FILE_NEW);
 736         const char *c_old = diff_get_color(use_color, DIFF_FILE_OLD);
 737         const char *c_context = diff_get_color(use_color, DIFF_CONTEXT);
 738         const char *c_reset = diff_get_color(use_color, DIFF_RESET);
 739
 740         if (result_deleted)
 741                 return; /* result deleted */
 742
 743         while (1) {
 744                 unsigned long hunk_end;
 745                 unsigned long rlines;
 746                 const char *hunk_comment = NULL;
 747                 unsigned long null_context = 0;
 748
 749                 while (lno <= cnt && !(sline[lno].flag & mark)) {
 750                         if (hunk_comment_line(sline[lno].bol))
 751                                 hunk_comment = sline[lno].bol;
 752                         lno++;
 753                 }
 754                 if (cnt < lno)
 755                         break;
 756                 else {
 757                         for (hunk_end = lno + 1; hunk_end <= cnt; hunk_end++)
 758                                 if (!(sline[hunk_end].flag & mark))
 759                                         break;
 760                 }
 761                 rlines = hunk_end - lno;
 762                 if (cnt < hunk_end)
 763                         rlines--; /* pointing at the last delete hunk */
 764
 765                 if (!context) {
 766                         /*
 767                          * Even when running with --unified=0, all
 768                          * lines in the hunk needs to be processed in
 769                          * the loop below in order to show the
 770                          * deletion recorded in lost_head.  However,
 771                          * we do not want to show the resulting line
 772                          * with all blank context markers in such a
 773                          * case.  Compensate.
 774                          */
 775                         unsigned long j;
 776                         for (j = lno; j < hunk_end; j++)
 777                                 if (!(sline[j].flag & (mark-1)))
 778                                         null_context++;
 779                         rlines -= null_context;
 780                 }
 781
 782                 printf("%s%s", line_prefix, c_frag);
 783                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 784                 for (i = 0; i < num_parent; i++)
 785                         show_parent_lno(sline, lno, hunk_end, i, null_context);
 786                 printf(" +%lu,%lu ", lno+1, rlines);
 787                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 788
 789                 if (hunk_comment) {
 790                         int comment_end = 0;
 791                         for (i = 0; i < 40; i++) {
 792                                 int ch = hunk_comment[i] & 0xff;
 793                                 if (!ch || ch == '\n')
 794                                         break;
 795                                 if (!isspace(ch))
 796                                     comment_end = i;
 797                         }
 798                         if (comment_end)
 799                                 printf("%s%s %s%s", c_reset,
 800                                                     c_context, c_reset,
 801                                                     c_func);
 802                         for (i = 0; i < comment_end; i++)
 803                                 putchar(hunk_comment[i]);
 804                 }
 805
 806                 printf("%s\n", c_reset);
 807                 while (lno < hunk_end) {
 808                         struct lline *ll;
 809                         int j;
 810                         unsigned long p_mask;
 811                         struct sline *sl = &sline[lno++];
 812                         ll = (sl->flag & no_pre_delete) ? NULL : sl->lost;
 813                         while (ll) {
 814                                 printf("%s%s", line_prefix, c_old);
 815                                 for (j = 0; j < num_parent; j++) {
 816                                         if (ll->parent_map & (1UL<<j))
 817                                                 putchar('-');
 818                                         else
 819                                                 putchar(' ');
 820                                 }
 821                                 show_line_to_eol(ll->line, -1, c_reset);
 822                                 ll = ll->next;
 823                         }
 824                         if (cnt < lno)
 825                                 break;
 826                         p_mask = 1;
 827                         fputs(line_prefix, stdout);
 828                         if (!(sl->flag & (mark-1))) {
 829                                 /*
 830                                  * This sline was here to hang the
 831                                  * lost lines in front of it.
 832                                  */
 833                                 if (!context)
 834                                         continue;
 835                                 fputs(c_context, stdout);
 836                         }
 837                         else
 838                                 fputs(c_new, stdout);
 839                         for (j = 0; j < num_parent; j++) {
 840                                 if (p_mask & sl->flag)
 841                                         putchar('+');
 842                                 else
 843                                         putchar(' ');
 844                                 p_mask <<= 1;
 845                         }
 846                         show_line_to_eol(sl->bol, sl->len, c_reset);
 847                 }
 848         }
 849 }
 850
 851 static void reuse_combine_diff(struct sline *sline, unsigned long cnt,
 852                                int i, int j)
 853 {
 854         /* We have already examined parent j and we know parent i
 855          * and parent j are the same, so reuse the combined result
 856          * of parent j for parent i.
 857          */
 858         unsigned long lno, imask, jmask;
 859         imask = (1UL<<i);
 860         jmask = (1UL<<j);
 861
 862         for (lno = 0; lno <= cnt; lno++) {
 863                 struct lline *ll = sline->lost;
 864                 sline->p_lno[i] = sline->p_lno[j];
 865                 while (ll) {
 866                         if (ll->parent_map & jmask)
 867                                 ll->parent_map |= imask;
 868                         ll = ll->next;
 869                 }
 870                 if (sline->flag & jmask)
 871                         sline->flag |= imask;
 872                 sline++;
 873         }
 874         /* the overall size of the file (sline[cnt]) */
 875         sline->p_lno[i] = sline->p_lno[j];
 876 }
 877
 878 static void dump_quoted_path(const char *head,
 879                              const char *prefix,
 880                              const char *path,
 881                              const char *line_prefix,
 882                              const char *c_meta, const char *c_reset)
 883 {
 884         static struct strbuf buf = STRBUF_INIT;
 885
 886         strbuf_reset(&buf);
 887         strbuf_addstr(&buf, line_prefix);
 888         strbuf_addstr(&buf, c_meta);
 889         strbuf_addstr(&buf, head);
 890         quote_two_c_style(&buf, prefix, path, 0);
 891         strbuf_addstr(&buf, c_reset);
 892         puts(buf.buf);
 893 }
 894
 895 static void show_combined_header(struct combine_diff_path *elem,
 896                                  int num_parent,
 897                                  int dense,
 898                                  struct rev_info *rev,
 899                                  const char *line_prefix,
 900                                  int mode_differs,
 901                                  int show_file_header)
 902 {
 903         struct diff_options *opt = &rev->diffopt;
 904         int abbrev = opt->flags.full_index ? GIT_SHA1_HEXSZ : DEFAULT_ABBREV;
 905         const char *a_prefix = opt->a_prefix ? opt->a_prefix : "a/";
 906         const char *b_prefix = opt->b_prefix ? opt->b_prefix : "b/";
 907         const char *c_meta = diff_get_color_opt(opt, DIFF_METAINFO);
 908         const char *c_reset = diff_get_color_opt(opt, DIFF_RESET);
 909         const char *abb;
 910         int added = 0;
 911         int deleted = 0;
 912         int i;
 913
 914         if (rev->loginfo && !rev->no_commit_id)
 915                 show_log(rev);
 916
 917         dump_quoted_path(dense ? "diff --cc " : "diff --combined ",
 918                          "", elem->path, line_prefix, c_meta, c_reset);
 919         printf("%s%sindex ", line_prefix, c_meta);
 920         for (i = 0; i < num_parent; i++) {
 921                 abb = find_unique_abbrev(&elem->parent[i].oid,
 922                                          abbrev);
 923                 printf("%s%s", i ? "," : "", abb);
 924         }
 925         abb = find_unique_abbrev(&elem->oid, abbrev);
 926         printf("..%s%s\n", abb, c_reset);
 927
 928         if (mode_differs) {
 929                 deleted = !elem->mode;
 930
 931                 /* We say it was added if nobody had it */
 932                 added = !deleted;
 933                 for (i = 0; added && i < num_parent; i++)
 934                         if (elem->parent[i].status !=
 935                             DIFF_STATUS_ADDED)
 936                                 added = 0;
 937                 if (added)
 938                         printf("%s%snew file mode %06o",
 939                                line_prefix, c_meta, elem->mode);
 940                 else {
 941                         if (deleted)
 942                                 printf("%s%sdeleted file ",
 943                                        line_prefix, c_meta);
 944                         printf("mode ");
 945                         for (i = 0; i < num_parent; i++) {
 946                                 printf("%s%06o", i ? "," : "",
 947                                        elem->parent[i].mode);
 948                         }
 949                         if (elem->mode)
 950                                 printf("..%06o", elem->mode);
 951                 }
 952                 printf("%s\n", c_reset);
 953         }
 954
 955         if (!show_file_header)
 956                 return;
 957
 958         if (added)
 959                 dump_quoted_path("--- ", "", "/dev/null",
 960                                  line_prefix, c_meta, c_reset);
 961         else
 962                 dump_quoted_path("--- ", a_prefix, elem->path,
 963                                  line_prefix, c_meta, c_reset);
 964         if (deleted)
 965                 dump_quoted_path("+++ ", "", "/dev/null",
 966                                  line_prefix, c_meta, c_reset);
 967         else
 968                 dump_quoted_path("+++ ", b_prefix, elem->path,
 969                                  line_prefix, c_meta, c_reset);
 970 }
 971
 972 static void show_patch_diff(struct combine_diff_path *elem, int num_parent,
 973                             int dense, int working_tree_file,
 974                             struct rev_info *rev)
 975 {
 976         struct diff_options *opt = &rev->diffopt;
 977         unsigned long result_size, cnt, lno;
 978         int result_deleted = 0;
 979         char *result, *cp;
 980         struct sline *sline; /* survived lines */
 981         int mode_differs = 0;
 982         int i, show_hunks;
 983         mmfile_t result_file;
 984         struct userdiff_driver *userdiff;
 985         struct userdiff_driver *textconv = NULL;
 986         int is_binary;
 987         const char *line_prefix = diff_line_prefix(opt);
 988
 989         context = opt->context;
 990         userdiff = userdiff_find_by_path(opt->repo->index, elem->path);
 991         if (!userdiff)
 992                 userdiff = userdiff_find_by_name("default");
 993         if (opt->flags.allow_textconv)
 994                 textconv = userdiff_get_textconv(userdiff);
 995
 996         /* Read the result of merge first */
 997         if (!working_tree_file)
 998                 result = grab_blob(opt->repo, &elem->oid, elem->mode, &result_size,
 999                                    textconv, elem->path);
1000         else {
1001                 /* Used by diff-tree to read from the working tree */
1002                 struct stat st;
1003                 int fd = -1;
1004
1005                 if (lstat(elem->path, &st) < 0)
1006                         goto deleted_file;
1007
1008                 if (S_ISLNK(st.st_mode)) {
1009                         struct strbuf buf = STRBUF_INIT;
1010
1011                         if (strbuf_readlink(&buf, elem->path, st.st_size) < 0) {
1012                                 error_errno("readlink(%s)", elem->path);
1013                                 return;
1014                         }
1015                         result_size = buf.len;
1016                         result = strbuf_detach(&buf, NULL);
1017                         elem->mode = canon_mode(st.st_mode);
1018                 } else if (S_ISDIR(st.st_mode)) {
1019                         struct object_id oid;
1020                         if (resolve_gitlink_ref(elem->path, "HEAD", &oid) < 0)
1021                                 result = grab_blob(opt->repo, &elem->oid,
1022                                                    elem->mode, &result_size,
1023                                                    NULL, NULL);
1024                         else
1025                                 result = grab_blob(opt->repo, &oid, elem->mode,
1026                                                    &result_size, NULL, NULL);
1027                 } else if (textconv) {
1028                         struct diff_filespec *df = alloc_filespec(elem->path);
1029                         fill_filespec(df, &null_oid, 0, st.st_mode);
1030                         result_size = fill_textconv(opt->repo, textconv, df, &result);
1031                         free_filespec(df);
1032                 } else if (0 <= (fd = open(elem->path, O_RDONLY))) {
1033                         size_t len = xsize_t(st.st_size);
1034                         ssize_t done;
1035                         int is_file, i;
1036
1037                         elem->mode = canon_mode(st.st_mode);
1038                         /* if symlinks don't work, assume symlink if all parents
1039                          * are symlinks
1040                          */
1041                         is_file = has_symlinks;
1042                         for (i = 0; !is_file && i < num_parent; i++)
1043                                 is_file = !S_ISLNK(elem->parent[i].mode);
1044                         if (!is_file)
1045                                 elem->mode = canon_mode(S_IFLNK);
1046
1047                         result_size = len;
1048                         result = xmallocz(len);
1049
1050                         done = read_in_full(fd, result, len);
1051                         if (done < 0)
1052                                 die_errno("read error '%s'", elem->path);
1053                         else if (done < len)
1054                                 die("early EOF '%s'", elem->path);
1055
1056                         /* If not a fake symlink, apply filters, e.g. autocrlf */
1057                         if (is_file) {
1058                                 struct strbuf buf = STRBUF_INIT;
1059
1060                                 if (convert_to_git(rev->diffopt.repo->index,
1061                                                    elem->path, result, len, &buf, global_conv_flags_eol)) {
1062                                         free(result);
1063                                         result = strbuf_detach(&buf, &len);
1064                                         result_size = len;
1065                                 }
1066                         }
1067                 }
1068                 else {
1069                 deleted_file:
1070                         result_deleted = 1;
1071                         result_size = 0;
1072                         elem->mode = 0;
1073                         result = xcalloc(1, 1);
1074                 }
1075
1076                 if (0 <= fd)
1077                         close(fd);
1078         }
1079
1080         for (i = 0; i < num_parent; i++) {
1081                 if (elem->parent[i].mode != elem->mode) {
1082                         mode_differs = 1;
1083                         break;
1084                 }
1085         }
1086
1087         if (textconv)
1088                 is_binary = 0;
1089         else if (userdiff->binary != -1)
1090                 is_binary = userdiff->binary;
1091         else {
1092                 is_binary = buffer_is_binary(result, result_size);
1093                 for (i = 0; !is_binary && i < num_parent; i++) {
1094                         char *buf;
1095                         unsigned long size;
1096                         buf = grab_blob(opt->repo,
1097                                         &elem->parent[i].oid,
1098                                         elem->parent[i].mode,
1099                                         &size, NULL, NULL);
1100                         if (buffer_is_binary(buf, size))
1101                                 is_binary = 1;
1102                         free(buf);
1103                 }
1104         }
1105         if (is_binary) {
1106                 show_combined_header(elem, num_parent, dense, rev,
1107                                      line_prefix, mode_differs, 0);
1108                 printf("Binary files differ\n");
1109                 free(result);
1110                 return;
1111         }
1112
1113         for (cnt = 0, cp = result; cp < result + result_size; cp++) {
1114                 if (*cp == '\n')
1115                         cnt++;
1116         }
1117         if (result_size && result[result_size-1] != '\n')
1118                 cnt++; /* incomplete line */
1119
1120         sline = xcalloc(st_add(cnt, 2), sizeof(*sline));
1121         sline[0].bol = result;
1122         for (lno = 0, cp = result; cp < result + result_size; cp++) {
1123                 if (*cp == '\n') {
1124                         sline[lno].len = cp - sline[lno].bol;
1125                         lno++;
1126                         if (lno < cnt)
1127                                 sline[lno].bol = cp + 1;
1128                 }
1129         }
1130         if (result_size && result[result_size-1] != '\n')
1131                 sline[cnt-1].len = result_size - (sline[cnt-1].bol - result);
1132
1133         result_file.ptr = result;
1134         result_file.size = result_size;
1135
1136         /* Even p_lno[cnt+1] is valid -- that is for the end line number
1137          * for deletion hunk at the end.
1138          */
1139         sline[0].p_lno = xcalloc(st_mult(st_add(cnt, 2), num_parent), sizeof(unsigned long));
1140         for (lno = 0; lno <= cnt; lno++)
1141                 sline[lno+1].p_lno = sline[lno].p_lno + num_parent;
1142
1143         for (i = 0; i < num_parent; i++) {
1144                 int j;
1145                 for (j = 0; j < i; j++) {
1146                         if (oideq(&elem->parent[i].oid,
1147                                   &elem->parent[j].oid)) {
1148                                 reuse_combine_diff(sline, cnt, i, j);
1149                                 break;
1150                         }
1151                 }
1152                 if (i <= j)
1153                         combine_diff(opt->repo,
1154                                      &elem->parent[i].oid,
1155                                      elem->parent[i].mode,
1156                                      &result_file, sline,
1157                                      cnt, i, num_parent, result_deleted,
1158                                      textconv, elem->path, opt->xdl_opts);
1159         }
1160
1161         show_hunks = make_hunks(sline, cnt, num_parent, dense);
1162
1163         if (show_hunks || mode_differs || working_tree_file) {
1164                 show_combined_header(elem, num_parent, dense, rev,
1165                                      line_prefix, mode_differs, 1);
1166                 dump_sline(sline, line_prefix, cnt, num_parent,
1167                            opt->use_color, result_deleted);
1168         }
1169         free(result);
1170
1171         for (lno = 0; lno < cnt; lno++) {
1172                 if (sline[lno].lost) {
1173                         struct lline *ll = sline[lno].lost;
1174                         while (ll) {
1175                                 struct lline *tmp = ll;
1176                                 ll = ll->next;
1177                                 free(tmp);
1178                         }
1179                 }
1180         }
1181         free(sline[0].p_lno);
1182         free(sline);
1183 }
1184
1185 static void show_raw_diff(struct combine_diff_path *p, int num_parent, struct rev_info *rev)
1186 {
1187         struct diff_options *opt = &rev->diffopt;
1188         int line_termination, inter_name_termination, i;
1189         const char *line_prefix = diff_line_prefix(opt);
1190
1191         line_termination = opt->line_termination;
1192         inter_name_termination = '\t';
1193         if (!line_termination)
1194                 inter_name_termination = 0;
1195
1196         if (rev->loginfo && !rev->no_commit_id)
1197                 show_log(rev);
1198
1199
1200         if (opt->output_format & DIFF_FORMAT_RAW) {
1201                 printf("%s", line_prefix);
1202
1203                 /* As many colons as there are parents */
1204                 for (i = 0; i < num_parent; i++)
1205                         putchar(':');
1206
1207                 /* Show the modes */
1208                 for (i = 0; i < num_parent; i++)
1209                         printf("%06o ", p->parent[i].mode);
1210                 printf("%06o", p->mode);
1211
1212                 /* Show sha1's */
1213                 for (i = 0; i < num_parent; i++)
1214                         printf(" %s", diff_aligned_abbrev(&p->parent[i].oid,
1215                                                           opt->abbrev));
1216                 printf(" %s ", diff_aligned_abbrev(&p->oid, opt->abbrev));
1217         }
1218
1219         if (opt->output_format & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS)) {
1220                 for (i = 0; i < num_parent; i++)
1221                         putchar(p->parent[i].status);
1222                 putchar(inter_name_termination);
1223         }
1224
1225         write_name_quoted(p->path, stdout, line_termination);
1226 }
1227
1228 /*
1229  * The result (p->elem) is from the working tree and their
1230  * parents are typically from multiple stages during a merge
1231  * (i.e. diff-files) or the state in HEAD and in the index
1232  * (i.e. diff-index).
1233  */
1234 void show_combined_diff(struct combine_diff_path *p,
1235                        int num_parent,
1236                        int dense,
1237                        struct rev_info *rev)
1238 {
1239         struct diff_options *opt = &rev->diffopt;
1240
1241         if (opt->output_format & (DIFF_FORMAT_RAW |
1242                                   DIFF_FORMAT_NAME |
1243                                   DIFF_FORMAT_NAME_STATUS))
1244                 show_raw_diff(p, num_parent, rev);
1245         else if (opt->output_format & DIFF_FORMAT_PATCH)
1246                 show_patch_diff(p, num_parent, dense, 1, rev);
1247 }
1248
1249 static void free_combined_pair(struct diff_filepair *pair)
1250 {
1251         free(pair->two);
1252         free(pair);
1253 }
1254
1255 /*
1256  * A combine_diff_path expresses N parents on the LHS against 1 merge
1257  * result. Synthesize a diff_filepair that has N entries on the "one"
1258  * side and 1 entry on the "two" side.
1259  *
1260  * In the future, we might want to add more data to combine_diff_path
1261  * so that we can fill fields we are ignoring (most notably, size) here,
1262  * but currently nobody uses it, so this should suffice for now.
1263  */
1264 static struct diff_filepair *combined_pair(struct combine_diff_path *p,
1265                                            int num_parent)
1266 {
1267         int i;
1268         struct diff_filepair *pair;
1269         struct diff_filespec *pool;
1270
1271         pair = xmalloc(sizeof(*pair));
1272         pool = xcalloc(st_add(num_parent, 1), sizeof(struct diff_filespec));
1273         pair->one = pool + 1;
1274         pair->two = pool;
1275
1276         for (i = 0; i < num_parent; i++) {
1277                 pair->one[i].path = p->path;
1278                 pair->one[i].mode = p->parent[i].mode;
1279                 oidcpy(&pair->one[i].oid, &p->parent[i].oid);
1280                 pair->one[i].oid_valid = !is_null_oid(&p->parent[i].oid);
1281                 pair->one[i].has_more_entries = 1;
1282         }
1283         pair->one[num_parent - 1].has_more_entries = 0;
1284
1285         pair->two->path = p->path;
1286         pair->two->mode = p->mode;
1287         oidcpy(&pair->two->oid, &p->oid);
1288         pair->two->oid_valid = !is_null_oid(&p->oid);
1289         return pair;
1290 }
1291
1292 static void handle_combined_callback(struct diff_options *opt,
1293                                      struct combine_diff_path *paths,
1294                                      int num_parent,
1295                                      int num_paths)
1296 {
1297         struct combine_diff_path *p;
1298         struct diff_queue_struct q;
1299         int i;
1300
1301         q.queue = xcalloc(num_paths, sizeof(struct diff_filepair *));
1302         q.alloc = num_paths;
1303         q.nr = num_paths;
1304         for (i = 0, p = paths; p; p = p->next)
1305                 q.queue[i++] = combined_pair(p, num_parent);
1306         opt->format_callback(&q, opt, opt->format_callback_data);
1307         for (i = 0; i < num_paths; i++)
1308                 free_combined_pair(q.queue[i]);
1309         free(q.queue);
1310 }
1311
1312 static const char *path_path(void *obj)
1313 {
1314         struct combine_diff_path *path = (struct combine_diff_path *)obj;
1315
1316         return path->path;
1317 }
1318
1319
1320 /* find set of paths that every parent touches */
1321 static struct combine_diff_path *find_paths_generic(const struct object_id *oid,
1322         const struct oid_array *parents, struct diff_options *opt)
1323 {
1324         struct combine_diff_path *paths = NULL;
1325         int i, num_parent = parents->nr;
1326
1327         int output_format = opt->output_format;
1328         const char *orderfile = opt->orderfile;
1329
1330         opt->output_format = DIFF_FORMAT_NO_OUTPUT;
1331         /* tell diff_tree to emit paths in sorted (=tree) order */
1332         opt->orderfile = NULL;
1333
1334         /* D(A,P1...Pn) = D(A,P1) ^ ... ^ D(A,Pn)  (wrt paths) */
1335         for (i = 0; i < num_parent; i++) {
1336                 /*
1337                  * show stat against the first parent even when doing
1338                  * combined diff.
1339                  */
1340                 int stat_opt = (output_format &
1341                                 (DIFF_FORMAT_NUMSTAT|DIFF_FORMAT_DIFFSTAT));
1342                 if (i == 0 && stat_opt)
1343                         opt->output_format = stat_opt;
1344                 else
1345                         opt->output_format = DIFF_FORMAT_NO_OUTPUT;
1346                 diff_tree_oid(&parents->oid[i], oid, "", opt);
1347                 diffcore_std(opt);
1348                 paths = intersect_paths(paths, i, num_parent);
1349
1350                 /* if showing diff, show it in requested order */
1351                 if (opt->output_format != DIFF_FORMAT_NO_OUTPUT &&
1352                     orderfile) {
1353                         diffcore_order(orderfile);
1354                 }
1355
1356                 diff_flush(opt);
1357         }
1358
1359         opt->output_format = output_format;
1360         opt->orderfile = orderfile;
1361         return paths;
1362 }
1363
1364
1365 /*
1366  * find set of paths that everybody touches, assuming diff is run without
1367  * rename/copy detection, etc, comparing all trees simultaneously (= faster).
1368  */
1369 static struct combine_diff_path *find_paths_multitree(
1370         const struct object_id *oid, const struct oid_array *parents,
1371         struct diff_options *opt)
1372 {
1373         int i, nparent = parents->nr;
1374         const struct object_id **parents_oid;
1375         struct combine_diff_path paths_head;
1376         struct strbuf base;
1377
1378         ALLOC_ARRAY(parents_oid, nparent);
1379         for (i = 0; i < nparent; i++)
1380                 parents_oid[i] = &parents->oid[i];
1381
1382         /* fake list head, so worker can assume it is non-NULL */
1383         paths_head.next = NULL;
1384
1385         strbuf_init(&base, PATH_MAX);
1386         diff_tree_paths(&paths_head, oid, parents_oid, nparent, &base, opt);
1387
1388         strbuf_release(&base);
1389         free(parents_oid);
1390         return paths_head.next;
1391 }
1392
1393
1394 void diff_tree_combined(const struct object_id *oid,
1395                         const struct oid_array *parents,
1396                         int dense,
1397                         struct rev_info *rev)
1398 {
1399         struct diff_options *opt = &rev->diffopt;
1400         struct diff_options diffopts;
1401         struct combine_diff_path *p, *paths;
1402         int i, num_paths, needsep, show_log_first, num_parent = parents->nr;
1403         int need_generic_pathscan;
1404
1405         /* nothing to do, if no parents */
1406         if (!num_parent)
1407                 return;
1408
1409         show_log_first = !!rev->loginfo && !rev->no_commit_id;
1410         needsep = 0;
1411         if (show_log_first) {
1412                 show_log(rev);
1413
1414                 if (rev->verbose_header && opt->output_format &&
1415                     opt->output_format != DIFF_FORMAT_NO_OUTPUT &&
1416                     !commit_format_is_empty(rev->commit_format))
1417                         printf("%s%c", diff_line_prefix(opt),
1418                                opt->line_termination);
1419         }
1420
1421         diffopts = *opt;
1422         copy_pathspec(&diffopts.pathspec, &opt->pathspec);
1423         diffopts.flags.recursive = 1;
1424         diffopts.flags.allow_external = 0;
1425
1426         /* find set of paths that everybody touches
1427          *
1428          * NOTE
1429          *
1430          * Diffcore transformations are bound to diff_filespec and logic
1431          * comparing two entries - i.e. they do not apply directly to combine
1432          * diff.
1433          *
1434          * If some of such transformations is requested - we launch generic
1435          * path scanning, which works significantly slower compared to
1436          * simultaneous all-trees-in-one-go scan in find_paths_multitree().
1437          *
1438          * TODO some of the filters could be ported to work on
1439          * combine_diff_paths - i.e. all functionality that skips paths, so in
1440          * theory, we could end up having only multitree path scanning.
1441          *
1442          * NOTE please keep this semantically in sync with diffcore_std()
1443          */
1444         need_generic_pathscan = opt->skip_stat_unmatch  ||
1445                         opt->flags.follow_renames       ||
1446                         opt->break_opt != -1    ||
1447                         opt->detect_rename      ||
1448                         (opt->pickaxe_opts & DIFF_PICKAXE_KINDS_MASK)   ||
1449                         opt->filter;
1450
1451
1452         if (need_generic_pathscan) {
1453                 /*
1454                  * NOTE generic case also handles --stat, as it computes
1455                  * diff(sha1,parent_i) for all i to do the job, specifically
1456                  * for parent0.
1457                  */
1458                 paths = find_paths_generic(oid, parents, &diffopts);
1459         }
1460         else {
1461                 int stat_opt;
1462                 paths = find_paths_multitree(oid, parents, &diffopts);
1463
1464                 /*
1465                  * show stat against the first parent even
1466                  * when doing combined diff.
1467                  */
1468                 stat_opt = (opt->output_format &
1469                                 (DIFF_FORMAT_NUMSTAT|DIFF_FORMAT_DIFFSTAT));
1470                 if (stat_opt) {
1471                         diffopts.output_format = stat_opt;
1472
1473                         diff_tree_oid(&parents->oid[0], oid, "", &diffopts);
1474                         diffcore_std(&diffopts);
1475                         if (opt->orderfile)
1476                                 diffcore_order(opt->orderfile);
1477                         diff_flush(&diffopts);
1478                 }
1479         }
1480
1481         /* find out number of surviving paths */
1482         for (num_paths = 0, p = paths; p; p = p->next)
1483                 num_paths++;
1484
1485         /* order paths according to diffcore_order */
1486         if (opt->orderfile && num_paths) {
1487                 struct obj_order *o;
1488
1489                 ALLOC_ARRAY(o, num_paths);
1490                 for (i = 0, p = paths; p; p = p->next, i++)
1491                         o[i].obj = p;
1492                 order_objects(opt->orderfile, path_path, o, num_paths);
1493                 for (i = 0; i < num_paths - 1; i++) {
1494                         p = o[i].obj;
1495                         p->next = o[i+1].obj;
1496                 }
1497
1498                 p = o[num_paths-1].obj;
1499                 p->next = NULL;
1500                 paths = o[0].obj;
1501                 free(o);
1502         }
1503
1504
1505         if (num_paths) {
1506                 if (opt->output_format & (DIFF_FORMAT_RAW |
1507                                           DIFF_FORMAT_NAME |
1508                                           DIFF_FORMAT_NAME_STATUS)) {
1509                         for (p = paths; p; p = p->next)
1510                                 show_raw_diff(p, num_parent, rev);
1511                         needsep = 1;
1512                 }
1513                 else if (opt->output_format &
1514                          (DIFF_FORMAT_NUMSTAT|DIFF_FORMAT_DIFFSTAT))
1515                         needsep = 1;
1516                 else if (opt->output_format & DIFF_FORMAT_CALLBACK)
1517                         handle_combined_callback(opt, paths, num_parent, num_paths);
1518
1519                 if (opt->output_format & DIFF_FORMAT_PATCH) {
1520                         if (needsep)
1521                                 printf("%s%c", diff_line_prefix(opt),
1522                                        opt->line_termination);
1523                         for (p = paths; p; p = p->next)
1524                                 show_patch_diff(p, num_parent, dense,
1525                                                 0, rev);
1526                 }
1527         }
1528
1529         /* Clean things up */
1530         while (paths) {
1531                 struct combine_diff_path *tmp = paths;
1532                 paths = paths->next;
1533                 free(tmp);
1534         }
1535
1536         clear_pathspec(&diffopts.pathspec);
1537 }
1538
1539 void diff_tree_combined_merge(const struct commit *commit, int dense,
1540                               struct rev_info *rev)
1541 {
1542         struct commit_list *parent = get_saved_parents(rev, commit);
1543         struct oid_array parents = OID_ARRAY_INIT;
1544
1545         while (parent) {
1546                 oid_array_append(&parents, &parent->item->object.oid);
1547                 parent = parent->next;
1548         }
1549         diff_tree_combined(&commit->object.oid, &parents, dense, rev);
1550         oid_array_clear(&parents);
1551 }