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