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_hunk(void *state_,
 349                          long ob, long on,
 350                          long nb, long nn,
 351                          const char *funcline, long funclen)
 352 {
 353         struct combine_diff_state *state = state_;
 354
 355         state->ob = ob;
 356         state->on = on;
 357         state->nb = nb;
 358         state->nn = nn;
 359         state->lno = state->nb;
 360         if (state->nn == 0) {
 361                 /* @@ -X,Y +N,0 @@ removed Y lines
 362                  * that would have come *after* line N
 363                  * in the result.  Our lost buckets hang
 364                  * to the line after the removed lines,
 365                  *
 366                  * Note that this is correct even when N == 0,
 367                  * in which case the hunk removes the first
 368                  * line in the file.
 369                  */
 370                 state->lost_bucket = &state->sline[state->nb];
 371                 if (!state->nb)
 372                         state->nb = 1;
 373         } else {
 374                 state->lost_bucket = &state->sline[state->nb-1];
 375         }
 376         if (!state->sline[state->nb-1].p_lno)
 377                 state->sline[state->nb-1].p_lno =
 378                         xcalloc(state->num_parent, sizeof(unsigned long));
 379         state->sline[state->nb-1].p_lno[state->n] = state->ob;
 380 }
 381
 382 static void consume_line(void *state_, char *line, unsigned long len)
 383 {
 384         struct combine_diff_state *state = state_;
 385         if (!state->lost_bucket)
 386                 return; /* not in any hunk yet */
 387         switch (line[0]) {
 388         case '-':
 389                 append_lost(state->lost_bucket, state->n, line+1, len-1);
 390                 break;
 391         case '+':
 392                 state->sline[state->lno-1].flag |= state->nmask;
 393                 state->lno++;
 394                 break;
 395         }
 396 }
 397
 398 static void combine_diff(struct repository *r,
 399                          const struct object_id *parent, unsigned int mode,
 400                          mmfile_t *result_file,
 401                          struct sline *sline, unsigned int cnt, int n,
 402                          int num_parent, int result_deleted,
 403                          struct userdiff_driver *textconv,
 404                          const char *path, long flags)
 405 {
 406         unsigned int p_lno, lno;
 407         unsigned long nmask = (1UL << n);
 408         xpparam_t xpp;
 409         xdemitconf_t xecfg;
 410         mmfile_t parent_file;
 411         struct combine_diff_state state;
 412         unsigned long sz;
 413
 414         if (result_deleted)
 415                 return; /* result deleted */
 416
 417         parent_file.ptr = grab_blob(r, parent, mode, &sz, textconv, path);
 418         parent_file.size = sz;
 419         memset(&xpp, 0, sizeof(xpp));
 420         xpp.flags = flags;
 421         memset(&xecfg, 0, sizeof(xecfg));
 422         memset(&state, 0, sizeof(state));
 423         state.nmask = nmask;
 424         state.sline = sline;
 425         state.lno = 1;
 426         state.num_parent = num_parent;
 427         state.n = n;
 428
 429         if (xdi_diff_outf(&parent_file, result_file, consume_hunk,
 430                           consume_line, &state, &xpp, &xecfg))
 431                 die("unable to generate combined diff for %s",
 432                     oid_to_hex(parent));
 433         free(parent_file.ptr);
 434
 435         /* Assign line numbers for this parent.
 436          *
 437          * sline[lno].p_lno[n] records the first line number
 438          * (counting from 1) for parent N if the final hunk display
 439          * started by showing sline[lno] (possibly showing the lost
 440          * lines attached to it first).
 441          */
 442         for (lno = 0,  p_lno = 1; lno <= cnt; lno++) {
 443                 struct lline *ll;
 444                 sline[lno].p_lno[n] = p_lno;
 445
 446                 /* Coalesce new lines */
 447                 if (sline[lno].plost.lost_head) {
 448                         struct sline *sl = &sline[lno];
 449                         sl->lost = coalesce_lines(sl->lost, &sl->lenlost,
 450                                                   sl->plost.lost_head,
 451                                                   sl->plost.len, n, flags);
 452                         sl->plost.lost_head = sl->plost.lost_tail = NULL;
 453                         sl->plost.len = 0;
 454                 }
 455
 456                 /* How many lines would this sline advance the p_lno? */
 457                 ll = sline[lno].lost;
 458                 while (ll) {
 459                         if (ll->parent_map & nmask)
 460                                 p_lno++; /* '-' means parent had it */
 461                         ll = ll->next;
 462                 }
 463                 if (lno < cnt && !(sline[lno].flag & nmask))
 464                         p_lno++; /* no '+' means parent had it */
 465         }
 466         sline[lno].p_lno[n] = p_lno; /* trailer */
 467 }
 468
 469 static unsigned long context = 3;
 470 static char combine_marker = '@';
 471
 472 static int interesting(struct sline *sline, unsigned long all_mask)
 473 {
 474         /* If some parents lost lines here, or if we have added to
 475          * some parent, it is interesting.
 476          */
 477         return ((sline->flag & all_mask) || sline->lost);
 478 }
 479
 480 static unsigned long adjust_hunk_tail(struct sline *sline,
 481                                       unsigned long all_mask,
 482                                       unsigned long hunk_begin,
 483                                       unsigned long i)
 484 {
 485         /* i points at the first uninteresting line.  If the last line
 486          * of the hunk was interesting only because it has some
 487          * deletion, then it is not all that interesting for the
 488          * purpose of giving trailing context lines.  This is because
 489          * we output '-' line and then unmodified sline[i-1] itself in
 490          * that case which gives us one extra context line.
 491          */
 492         if ((hunk_begin + 1 <= i) && !(sline[i-1].flag & all_mask))
 493                 i--;
 494         return i;
 495 }
 496
 497 static unsigned long find_next(struct sline *sline,
 498                                unsigned long mark,
 499                                unsigned long i,
 500                                unsigned long cnt,
 501                                int look_for_uninteresting)
 502 {
 503         /* We have examined up to i-1 and are about to look at i.
 504          * Find next interesting or uninteresting line.  Here,
 505          * "interesting" does not mean interesting(), but marked by
 506          * the give_context() function below (i.e. it includes context
 507          * lines that are not interesting to interesting() function
 508          * that are surrounded by interesting() ones.
 509          */
 510         while (i <= cnt)
 511                 if (look_for_uninteresting
 512                     ? !(sline[i].flag & mark)
 513                     : (sline[i].flag & mark))
 514                         return i;
 515                 else
 516                         i++;
 517         return i;
 518 }
 519
 520 static int give_context(struct sline *sline, unsigned long cnt, int num_parent)
 521 {
 522         unsigned long all_mask = (1UL<<num_parent) - 1;
 523         unsigned long mark = (1UL<<num_parent);
 524         unsigned long no_pre_delete = (2UL<<num_parent);
 525         unsigned long i;
 526
 527         /* Two groups of interesting lines may have a short gap of
 528          * uninteresting lines.  Connect such groups to give them a
 529          * bit of context.
 530          *
 531          * We first start from what the interesting() function says,
 532          * and mark them with "mark", and paint context lines with the
 533          * mark.  So interesting() would still say false for such context
 534          * lines but they are treated as "interesting" in the end.
 535          */
 536         i = find_next(sline, mark, 0, cnt, 0);
 537         if (cnt < i)
 538                 return 0;
 539
 540         while (i <= cnt) {
 541                 unsigned long j = (context < i) ? (i - context) : 0;
 542                 unsigned long k;
 543
 544                 /* Paint a few lines before the first interesting line. */
 545                 while (j < i) {
 546                         if (!(sline[j].flag & mark))
 547                                 sline[j].flag |= no_pre_delete;
 548                         sline[j++].flag |= mark;
 549                 }
 550
 551         again:
 552                 /* we know up to i is to be included.  where does the
 553                  * next uninteresting one start?
 554                  */
 555                 j = find_next(sline, mark, i, cnt, 1);
 556                 if (cnt < j)
 557                         break; /* the rest are all interesting */
 558
 559                 /* lookahead context lines */
 560                 k = find_next(sline, mark, j, cnt, 0);
 561                 j = adjust_hunk_tail(sline, all_mask, i, j);
 562
 563                 if (k < j + context) {
 564                         /* k is interesting and [j,k) are not, but
 565                          * paint them interesting because the gap is small.
 566                          */
 567                         while (j < k)
 568                                 sline[j++].flag |= mark;
 569                         i = k;
 570                         goto again;
 571                 }
 572
 573                 /* j is the first uninteresting line and there is
 574                  * no overlap beyond it within context lines.  Paint
 575                  * the trailing edge a bit.
 576                  */
 577                 i = k;
 578                 k = (j + context < cnt+1) ? j + context : cnt+1;
 579                 while (j < k)
 580                         sline[j++].flag |= mark;
 581         }
 582         return 1;
 583 }
 584
 585 static int make_hunks(struct sline *sline, unsigned long cnt,
 586                        int num_parent, int dense)
 587 {
 588         unsigned long all_mask = (1UL<<num_parent) - 1;
 589         unsigned long mark = (1UL<<num_parent);
 590         unsigned long i;
 591         int has_interesting = 0;
 592
 593         for (i = 0; i <= cnt; i++) {
 594                 if (interesting(&sline[i], all_mask))
 595                         sline[i].flag |= mark;
 596                 else
 597                         sline[i].flag &= ~mark;
 598         }
 599         if (!dense)
 600                 return give_context(sline, cnt, num_parent);
 601
 602         /* Look at each hunk, and if we have changes from only one
 603          * parent, or the changes are the same from all but one
 604          * parent, mark that uninteresting.
 605          */
 606         i = 0;
 607         while (i <= cnt) {
 608                 unsigned long j, hunk_begin, hunk_end;
 609                 unsigned long same_diff;
 610                 while (i <= cnt && !(sline[i].flag & mark))
 611                         i++;
 612                 if (cnt < i)
 613                         break; /* No more interesting hunks */
 614                 hunk_begin = i;
 615                 for (j = i + 1; j <= cnt; j++) {
 616                         if (!(sline[j].flag & mark)) {
 617                                 /* Look beyond the end to see if there
 618                                  * is an interesting line after this
 619                                  * hunk within context span.
 620                                  */
 621                                 unsigned long la; /* lookahead */
 622                                 int contin = 0;
 623                                 la = adjust_hunk_tail(sline, all_mask,
 624                                                      hunk_begin, j);
 625                                 la = (la + context < cnt + 1) ?
 626                                         (la + context) : cnt + 1;
 627                                 while (la && j <= --la) {
 628                                         if (sline[la].flag & mark) {
 629                                                 contin = 1;
 630                                                 break;
 631                                         }
 632                                 }
 633                                 if (!contin)
 634                                         break;
 635                                 j = la;
 636                         }
 637                 }
 638                 hunk_end = j;
 639
 640                 /* [i..hunk_end) are interesting.  Now is it really
 641                  * interesting?  We check if there are only two versions
 642                  * and the result matches one of them.  That is, we look
 643                  * at:
 644                  *   (+) line, which records lines added to which parents;
 645                  *       this line appears in the result.
 646                  *   (-) line, which records from what parents the line
 647                  *       was removed; this line does not appear in the result.
 648                  * then check the set of parents the result has difference
 649                  * from, from all lines.  If there are lines that has
 650                  * different set of parents that the result has differences
 651                  * from, that means we have more than two versions.
 652                  *
 653                  * Even when we have only two versions, if the result does
 654                  * not match any of the parents, the it should be considered
 655                  * interesting.  In such a case, we would have all '+' line.
 656                  * After passing the above "two versions" test, that would
 657                  * appear as "the same set of parents" to be "all parents".
 658                  */
 659                 same_diff = 0;
 660                 has_interesting = 0;
 661                 for (j = i; j < hunk_end && !has_interesting; j++) {
 662                         unsigned long this_diff = sline[j].flag & all_mask;
 663                         struct lline *ll = sline[j].lost;
 664                         if (this_diff) {
 665                                 /* This has some changes.  Is it the
 666                                  * same as others?
 667                                  */
 668                                 if (!same_diff)
 669                                         same_diff = this_diff;
 670                                 else if (same_diff != this_diff) {
 671                                         has_interesting = 1;
 672                                         break;
 673                                 }
 674                         }
 675                         while (ll && !has_interesting) {
 676                                 /* Lost this line from these parents;
 677                                  * who are they?  Are they the same?
 678                                  */
 679                                 this_diff = ll->parent_map;
 680                                 if (!same_diff)
 681                                         same_diff = this_diff;
 682                                 else if (same_diff != this_diff) {
 683                                         has_interesting = 1;
 684                                 }
 685                                 ll = ll->next;
 686                         }
 687                 }
 688
 689                 if (!has_interesting && same_diff != all_mask) {
 690                         /* This hunk is not that interesting after all */
 691                         for (j = hunk_begin; j < hunk_end; j++)
 692                                 sline[j].flag &= ~mark;
 693                 }
 694                 i = hunk_end;
 695         }
 696
 697         has_interesting = give_context(sline, cnt, num_parent);
 698         return has_interesting;
 699 }
 700
 701 static void show_parent_lno(struct sline *sline, unsigned long l0, unsigned long l1, int n, unsigned long null_context)
 702 {
 703         l0 = sline[l0].p_lno[n];
 704         l1 = sline[l1].p_lno[n];
 705         printf(" -%lu,%lu", l0, l1-l0-null_context);
 706 }
 707
 708 static int hunk_comment_line(const char *bol)
 709 {
 710         int ch;
 711
 712         if (!bol)
 713                 return 0;
 714         ch = *bol & 0xff;
 715         return (isalpha(ch) || ch == '_' || ch == '$');
 716 }
 717
 718 static void show_line_to_eol(const char *line, int len, const char *reset)
 719 {
 720         int saw_cr_at_eol = 0;
 721         if (len < 0)
 722                 len = strlen(line);
 723         saw_cr_at_eol = (len && line[len-1] == '\r');
 724
 725         printf("%.*s%s%s\n", len - saw_cr_at_eol, line,
 726                reset,
 727                saw_cr_at_eol ? "\r" : "");
 728 }
 729
 730 static void dump_sline(struct sline *sline, const char *line_prefix,
 731                        unsigned long cnt, int num_parent,
 732                        int use_color, int result_deleted)
 733 {
 734         unsigned long mark = (1UL<<num_parent);
 735         unsigned long no_pre_delete = (2UL<<num_parent);
 736         int i;
 737         unsigned long lno = 0;
 738         const char *c_frag = diff_get_color(use_color, DIFF_FRAGINFO);
 739         const char *c_func = diff_get_color(use_color, DIFF_FUNCINFO);
 740         const char *c_new = diff_get_color(use_color, DIFF_FILE_NEW);
 741         const char *c_old = diff_get_color(use_color, DIFF_FILE_OLD);
 742         const char *c_context = diff_get_color(use_color, DIFF_CONTEXT);
 743         const char *c_reset = diff_get_color(use_color, DIFF_RESET);
 744
 745         if (result_deleted)
 746                 return; /* result deleted */
 747
 748         while (1) {
 749                 unsigned long hunk_end;
 750                 unsigned long rlines;
 751                 const char *hunk_comment = NULL;
 752                 unsigned long null_context = 0;
 753
 754                 while (lno <= cnt && !(sline[lno].flag & mark)) {
 755                         if (hunk_comment_line(sline[lno].bol))
 756                                 hunk_comment = sline[lno].bol;
 757                         lno++;
 758                 }
 759                 if (cnt < lno)
 760                         break;
 761                 else {
 762                         for (hunk_end = lno + 1; hunk_end <= cnt; hunk_end++)
 763                                 if (!(sline[hunk_end].flag & mark))
 764                                         break;
 765                 }
 766                 rlines = hunk_end - lno;
 767                 if (cnt < hunk_end)
 768                         rlines--; /* pointing at the last delete hunk */
 769
 770                 if (!context) {
 771                         /*
 772                          * Even when running with --unified=0, all
 773                          * lines in the hunk needs to be processed in
 774                          * the loop below in order to show the
 775                          * deletion recorded in lost_head.  However,
 776                          * we do not want to show the resulting line
 777                          * with all blank context markers in such a
 778                          * case.  Compensate.
 779                          */
 780                         unsigned long j;
 781                         for (j = lno; j < hunk_end; j++)
 782                                 if (!(sline[j].flag & (mark-1)))
 783                                         null_context++;
 784                         rlines -= null_context;
 785                 }
 786
 787                 printf("%s%s", line_prefix, c_frag);
 788                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 789                 for (i = 0; i < num_parent; i++)
 790                         show_parent_lno(sline, lno, hunk_end, i, null_context);
 791                 printf(" +%lu,%lu ", lno+1, rlines);
 792                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 793
 794                 if (hunk_comment) {
 795                         int comment_end = 0;
 796                         for (i = 0; i < 40; i++) {
 797                                 int ch = hunk_comment[i] & 0xff;
 798                                 if (!ch || ch == '\n')
 799                                         break;
 800                                 if (!isspace(ch))
 801                                     comment_end = i;
 802                         }
 803                         if (comment_end)
 804                                 printf("%s%s %s%s", c_reset,
 805                                                     c_context, c_reset,
 806                                                     c_func);
 807                         for (i = 0; i < comment_end; i++)
 808                                 putchar(hunk_comment[i]);
 809                 }
 810
 811                 printf("%s\n", c_reset);
 812                 while (lno < hunk_end) {
 813                         struct lline *ll;
 814                         int j;
 815                         unsigned long p_mask;
 816                         struct sline *sl = &sline[lno++];
 817                         ll = (sl->flag & no_pre_delete) ? NULL : sl->lost;
 818                         while (ll) {
 819                                 printf("%s%s", line_prefix, c_old);
 820                                 for (j = 0; j < num_parent; j++) {
 821                                         if (ll->parent_map & (1UL<<j))
 822                                                 putchar('-');
 823                                         else
 824                                                 putchar(' ');
 825                                 }
 826                                 show_line_to_eol(ll->line, -1, c_reset);
 827                                 ll = ll->next;
 828                         }
 829                         if (cnt < lno)
 830                                 break;
 831                         p_mask = 1;
 832                         fputs(line_prefix, stdout);
 833                         if (!(sl->flag & (mark-1))) {
 834                                 /*
 835                                  * This sline was here to hang the
 836                                  * lost lines in front of it.
 837                                  */
 838                                 if (!context)
 839                                         continue;
 840                                 fputs(c_context, stdout);
 841                         }
 842                         else
 843                                 fputs(c_new, stdout);
 844                         for (j = 0; j < num_parent; j++) {
 845                                 if (p_mask & sl->flag)
 846                                         putchar('+');
 847                                 else
 848                                         putchar(' ');
 849                                 p_mask <<= 1;
 850                         }
 851                         show_line_to_eol(sl->bol, sl->len, c_reset);
 852                 }
 853         }
 854 }
 855
 856 static void reuse_combine_diff(struct sline *sline, unsigned long cnt,
 857                                int i, int j)
 858 {
 859         /* We have already examined parent j and we know parent i
 860          * and parent j are the same, so reuse the combined result
 861          * of parent j for parent i.
 862          */
 863         unsigned long lno, imask, jmask;
 864         imask = (1UL<<i);
 865         jmask = (1UL<<j);
 866
 867         for (lno = 0; lno <= cnt; lno++) {
 868                 struct lline *ll = sline->lost;
 869                 sline->p_lno[i] = sline->p_lno[j];
 870                 while (ll) {
 871                         if (ll->parent_map & jmask)
 872                                 ll->parent_map |= imask;
 873                         ll = ll->next;
 874                 }
 875                 if (sline->flag & jmask)
 876                         sline->flag |= imask;
 877                 sline++;
 878         }
 879         /* the overall size of the file (sline[cnt]) */
 880         sline->p_lno[i] = sline->p_lno[j];
 881 }
 882
 883 static void dump_quoted_path(const char *head,
 884                              const char *prefix,
 885                              const char *path,
 886                              const char *line_prefix,
 887                              const char *c_meta, const char *c_reset)
 888 {
 889         static struct strbuf buf = STRBUF_INIT;
 890
 891         strbuf_reset(&buf);
 892         strbuf_addstr(&buf, line_prefix);
 893         strbuf_addstr(&buf, c_meta);
 894         strbuf_addstr(&buf, head);
 895         quote_two_c_style(&buf, prefix, path, 0);
 896         strbuf_addstr(&buf, c_reset);
 897         puts(buf.buf);
 898 }
 899
 900 static void show_combined_header(struct combine_diff_path *elem,
 901                                  int num_parent,
 902                                  int dense,
 903                                  struct rev_info *rev,
 904                                  const char *line_prefix,
 905                                  int mode_differs,
 906                                  int show_file_header)
 907 {
 908         struct diff_options *opt = &rev->diffopt;
 909         int abbrev = opt->flags.full_index ? GIT_SHA1_HEXSZ : DEFAULT_ABBREV;
 910         const char *a_prefix = opt->a_prefix ? opt->a_prefix : "a/";
 911         const char *b_prefix = opt->b_prefix ? opt->b_prefix : "b/";
 912         const char *c_meta = diff_get_color_opt(opt, DIFF_METAINFO);
 913         const char *c_reset = diff_get_color_opt(opt, DIFF_RESET);
 914         const char *abb;
 915         int added = 0;
 916         int deleted = 0;
 917         int i;
 918
 919         if (rev->loginfo && !rev->no_commit_id)
 920                 show_log(rev);
 921
 922         dump_quoted_path(dense ? "diff --cc " : "diff --combined ",
 923                          "", elem->path, line_prefix, c_meta, c_reset);
 924         printf("%s%sindex ", line_prefix, c_meta);
 925         for (i = 0; i < num_parent; i++) {
 926                 abb = find_unique_abbrev(&elem->parent[i].oid,
 927                                          abbrev);
 928                 printf("%s%s", i ? "," : "", abb);
 929         }
 930         abb = find_unique_abbrev(&elem->oid, abbrev);
 931         printf("..%s%s\n", abb, c_reset);
 932
 933         if (mode_differs) {
 934                 deleted = !elem->mode;
 935
 936                 /* We say it was added if nobody had it */
 937                 added = !deleted;
 938                 for (i = 0; added && i < num_parent; i++)
 939                         if (elem->parent[i].status !=
 940                             DIFF_STATUS_ADDED)
 941                                 added = 0;
 942                 if (added)
 943                         printf("%s%snew file mode %06o",
 944                                line_prefix, c_meta, elem->mode);
 945                 else {
 946                         if (deleted)
 947                                 printf("%s%sdeleted file ",
 948                                        line_prefix, c_meta);
 949                         printf("mode ");
 950                         for (i = 0; i < num_parent; i++) {
 951                                 printf("%s%06o", i ? "," : "",
 952                                        elem->parent[i].mode);
 953                         }
 954                         if (elem->mode)
 955                                 printf("..%06o", elem->mode);
 956                 }
 957                 printf("%s\n", c_reset);
 958         }
 959
 960         if (!show_file_header)
 961                 return;
 962
 963         if (added)
 964                 dump_quoted_path("--- ", "", "/dev/null",
 965                                  line_prefix, c_meta, c_reset);
 966         else
 967                 dump_quoted_path("--- ", a_prefix, elem->path,
 968                                  line_prefix, c_meta, c_reset);
 969         if (deleted)
 970                 dump_quoted_path("+++ ", "", "/dev/null",
 971                                  line_prefix, c_meta, c_reset);
 972         else
 973                 dump_quoted_path("+++ ", b_prefix, elem->path,
 974                                  line_prefix, c_meta, c_reset);
 975 }
 976
 977 static void show_patch_diff(struct combine_diff_path *elem, int num_parent,
 978                             int dense, int working_tree_file,
 979                             struct rev_info *rev)
 980 {
 981         struct diff_options *opt = &rev->diffopt;
 982         unsigned long result_size, cnt, lno;
 983         int result_deleted = 0;
 984         char *result, *cp;
 985         struct sline *sline; /* survived lines */
 986         int mode_differs = 0;
 987         int i, show_hunks;
 988         mmfile_t result_file;
 989         struct userdiff_driver *userdiff;
 990         struct userdiff_driver *textconv = NULL;
 991         int is_binary;
 992         const char *line_prefix = diff_line_prefix(opt);
 993
 994         context = opt->context;
 995         userdiff = userdiff_find_by_path(opt->repo->index, elem->path);
 996         if (!userdiff)
 997                 userdiff = userdiff_find_by_name("default");
 998         if (opt->flags.allow_textconv)
 999                 textconv = userdiff_get_textconv(userdiff);
1000
1001         /* Read the result of merge first */
1002         if (!working_tree_file)
1003                 result = grab_blob(opt->repo, &elem->oid, elem->mode, &result_size,
1004                                    textconv, elem->path);
1005         else {
1006                 /* Used by diff-tree to read from the working tree */
1007                 struct stat st;
1008                 int fd = -1;
1009
1010                 if (lstat(elem->path, &st) < 0)
1011                         goto deleted_file;
1012
1013                 if (S_ISLNK(st.st_mode)) {
1014                         struct strbuf buf = STRBUF_INIT;
1015
1016                         if (strbuf_readlink(&buf, elem->path, st.st_size) < 0) {
1017                                 error_errno("readlink(%s)", elem->path);
1018                                 return;
1019                         }
1020                         result_size = buf.len;
1021                         result = strbuf_detach(&buf, NULL);
1022                         elem->mode = canon_mode(st.st_mode);
1023                 } else if (S_ISDIR(st.st_mode)) {
1024                         struct object_id oid;
1025                         if (resolve_gitlink_ref(elem->path, "HEAD", &oid) < 0)
1026                                 result = grab_blob(opt->repo, &elem->oid,
1027                                                    elem->mode, &result_size,
1028                                                    NULL, NULL);
1029                         else
1030                                 result = grab_blob(opt->repo, &oid, elem->mode,
1031                                                    &result_size, NULL, NULL);
1032                 } else if (textconv) {
1033                         struct diff_filespec *df = alloc_filespec(elem->path);
1034                         fill_filespec(df, &null_oid, 0, st.st_mode);
1035                         result_size = fill_textconv(opt->repo, textconv, df, &result);
1036                         free_filespec(df);
1037                 } else if (0 <= (fd = open(elem->path, O_RDONLY))) {
1038                         size_t len = xsize_t(st.st_size);
1039                         ssize_t done;
1040                         int is_file, i;
1041
1042                         elem->mode = canon_mode(st.st_mode);
1043                         /* if symlinks don't work, assume symlink if all parents
1044                          * are symlinks
1045                          */
1046                         is_file = has_symlinks;
1047                         for (i = 0; !is_file && i < num_parent; i++)
1048                                 is_file = !S_ISLNK(elem->parent[i].mode);
1049                         if (!is_file)
1050                                 elem->mode = canon_mode(S_IFLNK);
1051
1052                         result_size = len;
1053                         result = xmallocz(len);
1054
1055                         done = read_in_full(fd, result, len);
1056                         if (done < 0)
1057                                 die_errno("read error '%s'", elem->path);
1058                         else if (done < len)
1059                                 die("early EOF '%s'", elem->path);
1060
1061                         /* If not a fake symlink, apply filters, e.g. autocrlf */
1062                         if (is_file) {
1063                                 struct strbuf buf = STRBUF_INIT;
1064
1065                                 if (convert_to_git(rev->diffopt.repo->index,
1066                                                    elem->path, result, len, &buf, global_conv_flags_eol)) {
1067                                         free(result);
1068                                         result = strbuf_detach(&buf, &len);
1069                                         result_size = len;
1070                                 }
1071                         }
1072                 }
1073                 else {
1074                 deleted_file:
1075                         result_deleted = 1;
1076                         result_size = 0;
1077                         elem->mode = 0;
1078                         result = xcalloc(1, 1);
1079                 }
1080
1081                 if (0 <= fd)
1082                         close(fd);
1083         }
1084
1085         for (i = 0; i < num_parent; i++) {
1086                 if (elem->parent[i].mode != elem->mode) {
1087                         mode_differs = 1;
1088                         break;
1089                 }
1090         }
1091
1092         if (textconv)
1093                 is_binary = 0;
1094         else if (userdiff->binary != -1)
1095                 is_binary = userdiff->binary;
1096         else {
1097                 is_binary = buffer_is_binary(result, result_size);
1098                 for (i = 0; !is_binary && i < num_parent; i++) {
1099                         char *buf;
1100                         unsigned long size;
1101                         buf = grab_blob(opt->repo,
1102                                         &elem->parent[i].oid,
1103                                         elem->parent[i].mode,
1104                                         &size, NULL, NULL);
1105                         if (buffer_is_binary(buf, size))
1106                                 is_binary = 1;
1107                         free(buf);
1108                 }
1109         }
1110         if (is_binary) {
1111                 show_combined_header(elem, num_parent, dense, rev,
1112                                      line_prefix, mode_differs, 0);
1113                 printf("Binary files differ\n");
1114                 free(result);
1115                 return;
1116         }
1117
1118         for (cnt = 0, cp = result; cp < result + result_size; cp++) {
1119                 if (*cp == '\n')
1120                         cnt++;
1121         }
1122         if (result_size && result[result_size-1] != '\n')
1123                 cnt++; /* incomplete line */
1124
1125         sline = xcalloc(st_add(cnt, 2), sizeof(*sline));
1126         sline[0].bol = result;
1127         for (lno = 0, cp = result; cp < result + result_size; cp++) {
1128                 if (*cp == '\n') {
1129                         sline[lno].len = cp - sline[lno].bol;
1130                         lno++;
1131                         if (lno < cnt)
1132                                 sline[lno].bol = cp + 1;
1133                 }
1134         }
1135         if (result_size && result[result_size-1] != '\n')
1136                 sline[cnt-1].len = result_size - (sline[cnt-1].bol - result);
1137
1138         result_file.ptr = result;
1139         result_file.size = result_size;
1140
1141         /* Even p_lno[cnt+1] is valid -- that is for the end line number
1142          * for deletion hunk at the end.
1143          */
1144         sline[0].p_lno = xcalloc(st_mult(st_add(cnt, 2), num_parent), sizeof(unsigned long));
1145         for (lno = 0; lno <= cnt; lno++)
1146                 sline[lno+1].p_lno = sline[lno].p_lno + num_parent;
1147
1148         for (i = 0; i < num_parent; i++) {
1149                 int j;
1150                 for (j = 0; j < i; j++) {
1151                         if (oideq(&elem->parent[i].oid,
1152                                   &elem->parent[j].oid)) {
1153                                 reuse_combine_diff(sline, cnt, i, j);
1154                                 break;
1155                         }
1156                 }
1157                 if (i <= j)
1158                         combine_diff(opt->repo,
1159                                      &elem->parent[i].oid,
1160                                      elem->parent[i].mode,
1161                                      &result_file, sline,
1162                                      cnt, i, num_parent, result_deleted,
1163                                      textconv, elem->path, opt->xdl_opts);
1164         }
1165
1166         show_hunks = make_hunks(sline, cnt, num_parent, dense);
1167
1168         if (show_hunks || mode_differs || working_tree_file) {
1169                 show_combined_header(elem, num_parent, dense, rev,
1170                                      line_prefix, mode_differs, 1);
1171                 dump_sline(sline, line_prefix, cnt, num_parent,
1172                            opt->use_color, result_deleted);
1173         }
1174         free(result);
1175
1176         for (lno = 0; lno < cnt; lno++) {
1177                 if (sline[lno].lost) {
1178                         struct lline *ll = sline[lno].lost;
1179                         while (ll) {
1180                                 struct lline *tmp = ll;
1181                                 ll = ll->next;
1182                                 free(tmp);
1183                         }
1184                 }
1185         }
1186         free(sline[0].p_lno);
1187         free(sline);
1188 }
1189
1190 static void show_raw_diff(struct combine_diff_path *p, int num_parent, struct rev_info *rev)
1191 {
1192         struct diff_options *opt = &rev->diffopt;
1193         int line_termination, inter_name_termination, i;
1194         const char *line_prefix = diff_line_prefix(opt);
1195
1196         line_termination = opt->line_termination;
1197         inter_name_termination = '\t';
1198         if (!line_termination)
1199                 inter_name_termination = 0;
1200
1201         if (rev->loginfo && !rev->no_commit_id)
1202                 show_log(rev);
1203
1204
1205         if (opt->output_format & DIFF_FORMAT_RAW) {
1206                 printf("%s", line_prefix);
1207
1208                 /* As many colons as there are parents */
1209                 for (i = 0; i < num_parent; i++)
1210                         putchar(':');
1211
1212                 /* Show the modes */
1213                 for (i = 0; i < num_parent; i++)
1214                         printf("%06o ", p->parent[i].mode);
1215                 printf("%06o", p->mode);
1216
1217                 /* Show sha1's */
1218                 for (i = 0; i < num_parent; i++)
1219                         printf(" %s", diff_aligned_abbrev(&p->parent[i].oid,
1220                                                           opt->abbrev));
1221                 printf(" %s ", diff_aligned_abbrev(&p->oid, opt->abbrev));
1222         }
1223
1224         if (opt->output_format & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS)) {
1225                 for (i = 0; i < num_parent; i++)
1226                         putchar(p->parent[i].status);
1227                 putchar(inter_name_termination);
1228         }
1229
1230         write_name_quoted(p->path, stdout, line_termination);
1231 }
1232
1233 /*
1234  * The result (p->elem) is from the working tree and their
1235  * parents are typically from multiple stages during a merge
1236  * (i.e. diff-files) or the state in HEAD and in the index
1237  * (i.e. diff-index).
1238  */
1239 void show_combined_diff(struct combine_diff_path *p,
1240                        int num_parent,
1241                        int dense,
1242                        struct rev_info *rev)
1243 {
1244         struct diff_options *opt = &rev->diffopt;
1245
1246         if (opt->output_format & (DIFF_FORMAT_RAW |
1247                                   DIFF_FORMAT_NAME |
1248                                   DIFF_FORMAT_NAME_STATUS))
1249                 show_raw_diff(p, num_parent, rev);
1250         else if (opt->output_format & DIFF_FORMAT_PATCH)
1251                 show_patch_diff(p, num_parent, dense, 1, rev);
1252 }
1253
1254 static void free_combined_pair(struct diff_filepair *pair)
1255 {
1256         free(pair->two);
1257         free(pair);
1258 }
1259
1260 /*
1261  * A combine_diff_path expresses N parents on the LHS against 1 merge
1262  * result. Synthesize a diff_filepair that has N entries on the "one"
1263  * side and 1 entry on the "two" side.
1264  *
1265  * In the future, we might want to add more data to combine_diff_path
1266  * so that we can fill fields we are ignoring (most notably, size) here,
1267  * but currently nobody uses it, so this should suffice for now.
1268  */
1269 static struct diff_filepair *combined_pair(struct combine_diff_path *p,
1270                                            int num_parent)
1271 {
1272         int i;
1273         struct diff_filepair *pair;
1274         struct diff_filespec *pool;
1275
1276         pair = xmalloc(sizeof(*pair));
1277         pool = xcalloc(st_add(num_parent, 1), sizeof(struct diff_filespec));
1278         pair->one = pool + 1;
1279         pair->two = pool;
1280
1281         for (i = 0; i < num_parent; i++) {
1282                 pair->one[i].path = p->path;
1283                 pair->one[i].mode = p->parent[i].mode;
1284                 oidcpy(&pair->one[i].oid, &p->parent[i].oid);
1285                 pair->one[i].oid_valid = !is_null_oid(&p->parent[i].oid);
1286                 pair->one[i].has_more_entries = 1;
1287         }
1288         pair->one[num_parent - 1].has_more_entries = 0;
1289
1290         pair->two->path = p->path;
1291         pair->two->mode = p->mode;
1292         oidcpy(&pair->two->oid, &p->oid);
1293         pair->two->oid_valid = !is_null_oid(&p->oid);
1294         return pair;
1295 }
1296
1297 static void handle_combined_callback(struct diff_options *opt,
1298                                      struct combine_diff_path *paths,
1299                                      int num_parent,
1300                                      int num_paths)
1301 {
1302         struct combine_diff_path *p;
1303         struct diff_queue_struct q;
1304         int i;
1305
1306         q.queue = xcalloc(num_paths, sizeof(struct diff_filepair *));
1307         q.alloc = num_paths;
1308         q.nr = num_paths;
1309         for (i = 0, p = paths; p; p = p->next)
1310                 q.queue[i++] = combined_pair(p, num_parent);
1311         opt->format_callback(&q, opt, opt->format_callback_data);
1312         for (i = 0; i < num_paths; i++)
1313                 free_combined_pair(q.queue[i]);
1314         free(q.queue);
1315 }
1316
1317 static const char *path_path(void *obj)
1318 {
1319         struct combine_diff_path *path = (struct combine_diff_path *)obj;
1320
1321         return path->path;
1322 }
1323
1324
1325 /* find set of paths that every parent touches */
1326 static struct combine_diff_path *find_paths_generic(const struct object_id *oid,
1327         const struct oid_array *parents, struct diff_options *opt)
1328 {
1329         struct combine_diff_path *paths = NULL;
1330         int i, num_parent = parents->nr;
1331
1332         int output_format = opt->output_format;
1333         const char *orderfile = opt->orderfile;
1334
1335         opt->output_format = DIFF_FORMAT_NO_OUTPUT;
1336         /* tell diff_tree to emit paths in sorted (=tree) order */
1337         opt->orderfile = NULL;
1338
1339         /* D(A,P1...Pn) = D(A,P1) ^ ... ^ D(A,Pn)  (wrt paths) */
1340         for (i = 0; i < num_parent; i++) {
1341                 /*
1342                  * show stat against the first parent even when doing
1343                  * combined diff.
1344                  */
1345                 int stat_opt = (output_format &
1346                                 (DIFF_FORMAT_NUMSTAT|DIFF_FORMAT_DIFFSTAT));
1347                 if (i == 0 && stat_opt)
1348                         opt->output_format = stat_opt;
1349                 else
1350                         opt->output_format = DIFF_FORMAT_NO_OUTPUT;
1351                 diff_tree_oid(&parents->oid[i], oid, "", opt);
1352                 diffcore_std(opt);
1353                 paths = intersect_paths(paths, i, num_parent);
1354
1355                 /* if showing diff, show it in requested order */
1356                 if (opt->output_format != DIFF_FORMAT_NO_OUTPUT &&
1357                     orderfile) {
1358                         diffcore_order(orderfile);
1359                 }
1360
1361                 diff_flush(opt);
1362         }
1363
1364         opt->output_format = output_format;
1365         opt->orderfile = orderfile;
1366         return paths;
1367 }
1368
1369
1370 /*
1371  * find set of paths that everybody touches, assuming diff is run without
1372  * rename/copy detection, etc, comparing all trees simultaneously (= faster).
1373  */
1374 static struct combine_diff_path *find_paths_multitree(
1375         const struct object_id *oid, const struct oid_array *parents,
1376         struct diff_options *opt)
1377 {
1378         int i, nparent = parents->nr;
1379         const struct object_id **parents_oid;
1380         struct combine_diff_path paths_head;
1381         struct strbuf base;
1382
1383         ALLOC_ARRAY(parents_oid, nparent);
1384         for (i = 0; i < nparent; i++)
1385                 parents_oid[i] = &parents->oid[i];
1386
1387         /* fake list head, so worker can assume it is non-NULL */
1388         paths_head.next = NULL;
1389
1390         strbuf_init(&base, PATH_MAX);
1391         diff_tree_paths(&paths_head, oid, parents_oid, nparent, &base, opt);
1392
1393         strbuf_release(&base);
1394         free(parents_oid);
1395         return paths_head.next;
1396 }
1397
1398
1399 void diff_tree_combined(const struct object_id *oid,
1400                         const struct oid_array *parents,
1401                         int dense,
1402                         struct rev_info *rev)
1403 {
1404         struct diff_options *opt = &rev->diffopt;
1405         struct diff_options diffopts;
1406         struct combine_diff_path *p, *paths;
1407         int i, num_paths, needsep, show_log_first, num_parent = parents->nr;
1408         int need_generic_pathscan;
1409
1410         /* nothing to do, if no parents */
1411         if (!num_parent)
1412                 return;
1413
1414         show_log_first = !!rev->loginfo && !rev->no_commit_id;
1415         needsep = 0;
1416         if (show_log_first) {
1417                 show_log(rev);
1418
1419                 if (rev->verbose_header && opt->output_format &&
1420                     opt->output_format != DIFF_FORMAT_NO_OUTPUT &&
1421                     !commit_format_is_empty(rev->commit_format))
1422                         printf("%s%c", diff_line_prefix(opt),
1423                                opt->line_termination);
1424         }
1425
1426         diffopts = *opt;
1427         copy_pathspec(&diffopts.pathspec, &opt->pathspec);
1428         diffopts.flags.recursive = 1;
1429         diffopts.flags.allow_external = 0;
1430
1431         /* find set of paths that everybody touches
1432          *
1433          * NOTE
1434          *
1435          * Diffcore transformations are bound to diff_filespec and logic
1436          * comparing two entries - i.e. they do not apply directly to combine
1437          * diff.
1438          *
1439          * If some of such transformations is requested - we launch generic
1440          * path scanning, which works significantly slower compared to
1441          * simultaneous all-trees-in-one-go scan in find_paths_multitree().
1442          *
1443          * TODO some of the filters could be ported to work on
1444          * combine_diff_paths - i.e. all functionality that skips paths, so in
1445          * theory, we could end up having only multitree path scanning.
1446          *
1447          * NOTE please keep this semantically in sync with diffcore_std()
1448          */
1449         need_generic_pathscan = opt->skip_stat_unmatch  ||
1450                         opt->flags.follow_renames       ||
1451                         opt->break_opt != -1    ||
1452                         opt->detect_rename      ||
1453                         (opt->pickaxe_opts & DIFF_PICKAXE_KINDS_MASK)   ||
1454                         opt->filter;
1455
1456
1457         if (need_generic_pathscan) {
1458                 /*
1459                  * NOTE generic case also handles --stat, as it computes
1460                  * diff(sha1,parent_i) for all i to do the job, specifically
1461                  * for parent0.
1462                  */
1463                 paths = find_paths_generic(oid, parents, &diffopts);
1464         }
1465         else {
1466                 int stat_opt;
1467                 paths = find_paths_multitree(oid, parents, &diffopts);
1468
1469                 /*
1470                  * show stat against the first parent even
1471                  * when doing combined diff.
1472                  */
1473                 stat_opt = (opt->output_format &
1474                                 (DIFF_FORMAT_NUMSTAT|DIFF_FORMAT_DIFFSTAT));
1475                 if (stat_opt) {
1476                         diffopts.output_format = stat_opt;
1477
1478                         diff_tree_oid(&parents->oid[0], oid, "", &diffopts);
1479                         diffcore_std(&diffopts);
1480                         if (opt->orderfile)
1481                                 diffcore_order(opt->orderfile);
1482                         diff_flush(&diffopts);
1483                 }
1484         }
1485
1486         /* find out number of surviving paths */
1487         for (num_paths = 0, p = paths; p; p = p->next)
1488                 num_paths++;
1489
1490         /* order paths according to diffcore_order */
1491         if (opt->orderfile && num_paths) {
1492                 struct obj_order *o;
1493
1494                 ALLOC_ARRAY(o, num_paths);
1495                 for (i = 0, p = paths; p; p = p->next, i++)
1496                         o[i].obj = p;
1497                 order_objects(opt->orderfile, path_path, o, num_paths);
1498                 for (i = 0; i < num_paths - 1; i++) {
1499                         p = o[i].obj;
1500                         p->next = o[i+1].obj;
1501                 }
1502
1503                 p = o[num_paths-1].obj;
1504                 p->next = NULL;
1505                 paths = o[0].obj;
1506                 free(o);
1507         }
1508
1509
1510         if (num_paths) {
1511                 if (opt->output_format & (DIFF_FORMAT_RAW |
1512                                           DIFF_FORMAT_NAME |
1513                                           DIFF_FORMAT_NAME_STATUS)) {
1514                         for (p = paths; p; p = p->next)
1515                                 show_raw_diff(p, num_parent, rev);
1516                         needsep = 1;
1517                 }
1518                 else if (opt->output_format &
1519                          (DIFF_FORMAT_NUMSTAT|DIFF_FORMAT_DIFFSTAT))
1520                         needsep = 1;
1521                 else if (opt->output_format & DIFF_FORMAT_CALLBACK)
1522                         handle_combined_callback(opt, paths, num_parent, num_paths);
1523
1524                 if (opt->output_format & DIFF_FORMAT_PATCH) {
1525                         if (needsep)
1526                                 printf("%s%c", diff_line_prefix(opt),
1527                                        opt->line_termination);
1528                         for (p = paths; p; p = p->next)
1529                                 show_patch_diff(p, num_parent, dense,
1530                                                 0, rev);
1531                 }
1532         }
1533
1534         /* Clean things up */
1535         while (paths) {
1536                 struct combine_diff_path *tmp = paths;
1537                 paths = paths->next;
1538                 free(tmp);
1539         }
1540
1541         clear_pathspec(&diffopts.pathspec);
1542 }
1543
1544 void diff_tree_combined_merge(const struct commit *commit, int dense,
1545                               struct rev_info *rev)
1546 {
1547         struct commit_list *parent = get_saved_parents(rev, commit);
1548         struct oid_array parents = OID_ARRAY_INIT;
1549
1550         while (parent) {
1551                 oid_array_append(&parents, &parent->item->object.oid);
1552                 parent = parent->next;
1553         }
1554         diff_tree_combined(&commit->object.oid, &parents, dense, rev);
1555         oid_array_clear(&parents);
1556 }