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

   1 #include "cache.h"
   2 #include "commit.h"
   3 #include "blob.h"
   4 #include "diff.h"
   5 #include "diffcore.h"
   6 #include "quote.h"
   7 #include "xdiff-interface.h"
   8 #include "xdiff/xmacros.h"
   9 #include "log-tree.h"
  10 #include "refs.h"
  11 #include "userdiff.h"
  12 #include "sha1-array.h"
  13 #include "revision.h"
  14
  15 static struct combine_diff_path *intersect_paths(struct combine_diff_path *curr, int n, int num_parent)
  16 {
  17         struct diff_queue_struct *q = &diff_queued_diff;
  18         struct combine_diff_path *p, **tail = &curr;
  19         int i, cmp;
  20
  21         if (!n) {
  22                 for (i = 0; i < q->nr; i++) {
  23                         int len;
  24                         const char *path;
  25                         if (diff_unmodified_pair(q->queue[i]))
  26                                 continue;
  27                         path = q->queue[i]->two->path;
  28                         len = strlen(path);
  29                         p = xmalloc(combine_diff_path_size(num_parent, len));
  30                         p->path = (char *) &(p->parent[num_parent]);
  31                         memcpy(p->path, path, len);
  32                         p->path[len] = 0;
  33                         p->next = NULL;
  34                         memset(p->parent, 0,
  35                                sizeof(p->parent[0]) * num_parent);
  36
  37                         hashcpy(p->sha1, q->queue[i]->two->sha1);
  38                         p->mode = q->queue[i]->two->mode;
  39                         hashcpy(p->parent[n].sha1, q->queue[i]->one->sha1);
  40                         p->parent[n].mode = q->queue[i]->one->mode;
  41                         p->parent[n].status = q->queue[i]->status;
  42                         *tail = p;
  43                         tail = &p->next;
  44                 }
  45                 return curr;
  46         }
  47
  48         /*
  49          * paths in curr (linked list) and q->queue[] (array) are
  50          * both sorted in the tree order.
  51          */
  52         i = 0;
  53         while ((p = *tail) != NULL) {
  54                 cmp = ((i >= q->nr)
  55                        ? -1 : strcmp(p->path, q->queue[i]->two->path));
  56
  57                 if (cmp < 0) {
  58                         /* p->path not in q->queue[]; drop it */
  59                         *tail = p->next;
  60                         free(p);
  61                         continue;
  62                 }
  63
  64                 if (cmp > 0) {
  65                         /* q->queue[i] not in p->path; skip it */
  66                         i++;
  67                         continue;
  68                 }
  69
  70                 hashcpy(p->parent[n].sha1, q->queue[i]->one->sha1);
  71                 p->parent[n].mode = q->queue[i]->one->mode;
  72                 p->parent[n].status = q->queue[i]->status;
  73
  74                 tail = &p->next;
  75                 i++;
  76         }
  77         return curr;
  78 }
  79
  80 /* Lines lost from parent */
  81 struct lline {
  82         struct lline *next, *prev;
  83         int len;
  84         unsigned long parent_map;
  85         char line[FLEX_ARRAY];
  86 };
  87
  88 /* Lines lost from current parent (before coalescing) */
  89 struct plost {
  90         struct lline *lost_head, *lost_tail;
  91         int len;
  92 };
  93
  94 /* Lines surviving in the merge result */
  95 struct sline {
  96         /* Accumulated and coalesced lost lines */
  97         struct lline *lost;
  98         int lenlost;
  99         struct plost plost;
 100         char *bol;
 101         int len;
 102         /* bit 0 up to (N-1) are on if the parent has this line (i.e.
 103          * we did not change it).
 104          * bit N is used for "interesting" lines, including context.
 105          * bit (N+1) is used for "do not show deletion before this".
 106          */
 107         unsigned long flag;
 108         unsigned long *p_lno;
 109 };
 110
 111 static int match_string_spaces(const char *line1, int len1,
 112                                const char *line2, int len2,
 113                                long flags)
 114 {
 115         if (flags & XDF_WHITESPACE_FLAGS) {
 116                 for (; len1 > 0 && XDL_ISSPACE(line1[len1 - 1]); len1--);
 117                 for (; len2 > 0 && XDL_ISSPACE(line2[len2 - 1]); len2--);
 118         }
 119
 120         if (!(flags & (XDF_IGNORE_WHITESPACE | XDF_IGNORE_WHITESPACE_CHANGE)))
 121                 return (len1 == len2 && !memcmp(line1, line2, len1));
 122
 123         while (len1 > 0 && len2 > 0) {
 124                 len1--;
 125                 len2--;
 126                 if (XDL_ISSPACE(line1[len1]) || XDL_ISSPACE(line2[len2])) {
 127                         if ((flags & XDF_IGNORE_WHITESPACE_CHANGE) &&
 128                             (!XDL_ISSPACE(line1[len1]) || !XDL_ISSPACE(line2[len2])))
 129                                 return 0;
 130
 131                         for (; len1 > 0 && XDL_ISSPACE(line1[len1]); len1--);
 132                         for (; len2 > 0 && XDL_ISSPACE(line2[len2]); len2--);
 133                 }
 134                 if (line1[len1] != line2[len2])
 135                         return 0;
 136         }
 137
 138         if (flags & XDF_IGNORE_WHITESPACE) {
 139                 /* Consume remaining spaces */
 140                 for (; len1 > 0 && XDL_ISSPACE(line1[len1 - 1]); len1--);
 141                 for (; len2 > 0 && XDL_ISSPACE(line2[len2 - 1]); len2--);
 142         }
 143
 144         /* We matched full line1 and line2 */
 145         if (!len1 && !len2)
 146                 return 1;
 147
 148         return 0;
 149 }
 150
 151 enum coalesce_direction { MATCH, BASE, NEW };
 152
 153 /* Coalesce new lines into base by finding LCS */
 154 static struct lline *coalesce_lines(struct lline *base, int *lenbase,
 155                                     struct lline *new, int lennew,
 156                                     unsigned long parent, long flags)
 157 {
 158         int **lcs;
 159         enum coalesce_direction **directions;
 160         struct lline *baseend, *newend = NULL;
 161         int i, j, origbaselen = *lenbase;
 162
 163         if (new == NULL)
 164                 return base;
 165
 166         if (base == NULL) {
 167                 *lenbase = lennew;
 168                 return new;
 169         }
 170
 171         /*
 172          * Coalesce new lines into base by finding the LCS
 173          * - Create the table to run dynamic programming
 174          * - Compute the LCS
 175          * - Then reverse read the direction structure:
 176          *   - If we have MATCH, assign parent to base flag, and consume
 177          *   both baseend and newend
 178          *   - Else if we have BASE, consume baseend
 179          *   - Else if we have NEW, insert newend lline into base and
 180          *   consume newend
 181          */
 182         lcs = xcalloc(origbaselen + 1, sizeof(int*));
 183         directions = xcalloc(origbaselen + 1, sizeof(enum coalesce_direction*));
 184         for (i = 0; i < origbaselen + 1; i++) {
 185                 lcs[i] = xcalloc(lennew + 1, sizeof(int));
 186                 directions[i] = xcalloc(lennew + 1, sizeof(enum coalesce_direction));
 187                 directions[i][0] = BASE;
 188         }
 189         for (j = 1; j < lennew + 1; j++)
 190                 directions[0][j] = NEW;
 191
 192         for (i = 1, baseend = base; i < origbaselen + 1; i++) {
 193                 for (j = 1, newend = new; j < lennew + 1; j++) {
 194                         if (match_string_spaces(baseend->line, baseend->len,
 195                                                 newend->line, newend->len, flags)) {
 196                                 lcs[i][j] = lcs[i - 1][j - 1] + 1;
 197                                 directions[i][j] = MATCH;
 198                         } else if (lcs[i][j - 1] >= lcs[i - 1][j]) {
 199                                 lcs[i][j] = lcs[i][j - 1];
 200                                 directions[i][j] = NEW;
 201                         } else {
 202                                 lcs[i][j] = lcs[i - 1][j];
 203                                 directions[i][j] = BASE;
 204                         }
 205                         if (newend->next)
 206                                 newend = newend->next;
 207                 }
 208                 if (baseend->next)
 209                         baseend = baseend->next;
 210         }
 211
 212         for (i = 0; i < origbaselen + 1; i++)
 213                 free(lcs[i]);
 214         free(lcs);
 215
 216         /* At this point, baseend and newend point to the end of each lists */
 217         i--;
 218         j--;
 219         while (i != 0 || j != 0) {
 220                 if (directions[i][j] == MATCH) {
 221                         baseend->parent_map |= 1<<parent;
 222                         baseend = baseend->prev;
 223                         newend = newend->prev;
 224                         i--;
 225                         j--;
 226                 } else if (directions[i][j] == NEW) {
 227                         struct lline *lline;
 228
 229                         lline = newend;
 230                         /* Remove lline from new list and update newend */
 231                         if (lline->prev)
 232                                 lline->prev->next = lline->next;
 233                         else
 234                                 new = lline->next;
 235                         if (lline->next)
 236                                 lline->next->prev = lline->prev;
 237
 238                         newend = lline->prev;
 239                         j--;
 240
 241                         /* Add lline to base list */
 242                         if (baseend) {
 243                                 lline->next = baseend->next;
 244                                 lline->prev = baseend;
 245                                 if (lline->prev)
 246                                         lline->prev->next = lline;
 247                         }
 248                         else {
 249                                 lline->next = base;
 250                                 base = lline;
 251                         }
 252                         (*lenbase)++;
 253
 254                         if (lline->next)
 255                                 lline->next->prev = lline;
 256
 257                 } else {
 258                         baseend = baseend->prev;
 259                         i--;
 260                 }
 261         }
 262
 263         newend = new;
 264         while (newend) {
 265                 struct lline *lline = newend;
 266                 newend = newend->next;
 267                 free(lline);
 268         }
 269
 270         for (i = 0; i < origbaselen + 1; i++)
 271                 free(directions[i]);
 272         free(directions);
 273
 274         return base;
 275 }
 276
 277 static char *grab_blob(const unsigned char *sha1, unsigned int mode,
 278                        unsigned long *size, struct userdiff_driver *textconv,
 279                        const char *path)
 280 {
 281         char *blob;
 282         enum object_type type;
 283
 284         if (S_ISGITLINK(mode)) {
 285                 blob = xmalloc(100);
 286                 *size = snprintf(blob, 100,
 287                                  "Subproject commit %s\n", sha1_to_hex(sha1));
 288         } else if (is_null_sha1(sha1)) {
 289                 /* deleted blob */
 290                 *size = 0;
 291                 return xcalloc(1, 1);
 292         } else if (textconv) {
 293                 struct diff_filespec *df = alloc_filespec(path);
 294                 fill_filespec(df, sha1, 1, mode);
 295                 *size = fill_textconv(textconv, df, &blob);
 296                 free_filespec(df);
 297         } else {
 298                 blob = read_sha1_file(sha1, &type, size);
 299                 if (type != OBJ_BLOB)
 300                         die("object '%s' is not a blob!", sha1_to_hex(sha1));
 301         }
 302         return blob;
 303 }
 304
 305 static void append_lost(struct sline *sline, int n, const char *line, int len)
 306 {
 307         struct lline *lline;
 308         unsigned long this_mask = (1UL<<n);
 309         if (line[len-1] == '\n')
 310                 len--;
 311
 312         lline = xmalloc(sizeof(*lline) + len + 1);
 313         lline->len = len;
 314         lline->next = NULL;
 315         lline->prev = sline->plost.lost_tail;
 316         if (lline->prev)
 317                 lline->prev->next = lline;
 318         else
 319                 sline->plost.lost_head = lline;
 320         sline->plost.lost_tail = lline;
 321         sline->plost.len++;
 322         lline->parent_map = this_mask;
 323         memcpy(lline->line, line, len);
 324         lline->line[len] = 0;
 325 }
 326
 327 struct combine_diff_state {
 328         unsigned int lno;
 329         int ob, on, nb, nn;
 330         unsigned long nmask;
 331         int num_parent;
 332         int n;
 333         struct sline *sline;
 334         struct sline *lost_bucket;
 335 };
 336
 337 static void consume_line(void *state_, char *line, unsigned long len)
 338 {
 339         struct combine_diff_state *state = state_;
 340         if (5 < len && !memcmp("@@ -", line, 4)) {
 341                 if (parse_hunk_header(line, len,
 342                                       &state->ob, &state->on,
 343                                       &state->nb, &state->nn))
 344                         return;
 345                 state->lno = state->nb;
 346                 if (state->nn == 0) {
 347                         /* @@ -X,Y +N,0 @@ removed Y lines
 348                          * that would have come *after* line N
 349                          * in the result.  Our lost buckets hang
 350                          * to the line after the removed lines,
 351                          *
 352                          * Note that this is correct even when N == 0,
 353                          * in which case the hunk removes the first
 354                          * line in the file.
 355                          */
 356                         state->lost_bucket = &state->sline[state->nb];
 357                         if (!state->nb)
 358                                 state->nb = 1;
 359                 } else {
 360                         state->lost_bucket = &state->sline[state->nb-1];
 361                 }
 362                 if (!state->sline[state->nb-1].p_lno)
 363                         state->sline[state->nb-1].p_lno =
 364                                 xcalloc(state->num_parent,
 365                                         sizeof(unsigned long));
 366                 state->sline[state->nb-1].p_lno[state->n] = state->ob;
 367                 return;
 368         }
 369         if (!state->lost_bucket)
 370                 return; /* not in any hunk yet */
 371         switch (line[0]) {
 372         case '-':
 373                 append_lost(state->lost_bucket, state->n, line+1, len-1);
 374                 break;
 375         case '+':
 376                 state->sline[state->lno-1].flag |= state->nmask;
 377                 state->lno++;
 378                 break;
 379         }
 380 }
 381
 382 static void combine_diff(const unsigned char *parent, unsigned int mode,
 383                          mmfile_t *result_file,
 384                          struct sline *sline, unsigned int cnt, int n,
 385                          int num_parent, int result_deleted,
 386                          struct userdiff_driver *textconv,
 387                          const char *path, long flags)
 388 {
 389         unsigned int p_lno, lno;
 390         unsigned long nmask = (1UL << n);
 391         xpparam_t xpp;
 392         xdemitconf_t xecfg;
 393         mmfile_t parent_file;
 394         struct combine_diff_state state;
 395         unsigned long sz;
 396
 397         if (result_deleted)
 398                 return; /* result deleted */
 399
 400         parent_file.ptr = grab_blob(parent, mode, &sz, textconv, path);
 401         parent_file.size = sz;
 402         memset(&xpp, 0, sizeof(xpp));
 403         xpp.flags = flags;
 404         memset(&xecfg, 0, sizeof(xecfg));
 405         memset(&state, 0, sizeof(state));
 406         state.nmask = nmask;
 407         state.sline = sline;
 408         state.lno = 1;
 409         state.num_parent = num_parent;
 410         state.n = n;
 411
 412         xdi_diff_outf(&parent_file, result_file, consume_line, &state,
 413                       &xpp, &xecfg);
 414         free(parent_file.ptr);
 415
 416         /* Assign line numbers for this parent.
 417          *
 418          * sline[lno].p_lno[n] records the first line number
 419          * (counting from 1) for parent N if the final hunk display
 420          * started by showing sline[lno] (possibly showing the lost
 421          * lines attached to it first).
 422          */
 423         for (lno = 0,  p_lno = 1; lno <= cnt; lno++) {
 424                 struct lline *ll;
 425                 sline[lno].p_lno[n] = p_lno;
 426
 427                 /* Coalesce new lines */
 428                 if (sline[lno].plost.lost_head) {
 429                         struct sline *sl = &sline[lno];
 430                         sl->lost = coalesce_lines(sl->lost, &sl->lenlost,
 431                                                   sl->plost.lost_head,
 432                                                   sl->plost.len, n, flags);
 433                         sl->plost.lost_head = sl->plost.lost_tail = NULL;
 434                         sl->plost.len = 0;
 435                 }
 436
 437                 /* How many lines would this sline advance the p_lno? */
 438                 ll = sline[lno].lost;
 439                 while (ll) {
 440                         if (ll->parent_map & nmask)
 441                                 p_lno++; /* '-' means parent had it */
 442                         ll = ll->next;
 443                 }
 444                 if (lno < cnt && !(sline[lno].flag & nmask))
 445                         p_lno++; /* no '+' means parent had it */
 446         }
 447         sline[lno].p_lno[n] = p_lno; /* trailer */
 448 }
 449
 450 static unsigned long context = 3;
 451 static char combine_marker = '@';
 452
 453 static int interesting(struct sline *sline, unsigned long all_mask)
 454 {
 455         /* If some parents lost lines here, or if we have added to
 456          * some parent, it is interesting.
 457          */
 458         return ((sline->flag & all_mask) || sline->lost);
 459 }
 460
 461 static unsigned long adjust_hunk_tail(struct sline *sline,
 462                                       unsigned long all_mask,
 463                                       unsigned long hunk_begin,
 464                                       unsigned long i)
 465 {
 466         /* i points at the first uninteresting line.  If the last line
 467          * of the hunk was interesting only because it has some
 468          * deletion, then it is not all that interesting for the
 469          * purpose of giving trailing context lines.  This is because
 470          * we output '-' line and then unmodified sline[i-1] itself in
 471          * that case which gives us one extra context line.
 472          */
 473         if ((hunk_begin + 1 <= i) && !(sline[i-1].flag & all_mask))
 474                 i--;
 475         return i;
 476 }
 477
 478 static unsigned long find_next(struct sline *sline,
 479                                unsigned long mark,
 480                                unsigned long i,
 481                                unsigned long cnt,
 482                                int look_for_uninteresting)
 483 {
 484         /* We have examined up to i-1 and are about to look at i.
 485          * Find next interesting or uninteresting line.  Here,
 486          * "interesting" does not mean interesting(), but marked by
 487          * the give_context() function below (i.e. it includes context
 488          * lines that are not interesting to interesting() function
 489          * that are surrounded by interesting() ones.
 490          */
 491         while (i <= cnt)
 492                 if (look_for_uninteresting
 493                     ? !(sline[i].flag & mark)
 494                     : (sline[i].flag & mark))
 495                         return i;
 496                 else
 497                         i++;
 498         return i;
 499 }
 500
 501 static int give_context(struct sline *sline, unsigned long cnt, int num_parent)
 502 {
 503         unsigned long all_mask = (1UL<<num_parent) - 1;
 504         unsigned long mark = (1UL<<num_parent);
 505         unsigned long no_pre_delete = (2UL<<num_parent);
 506         unsigned long i;
 507
 508         /* Two groups of interesting lines may have a short gap of
 509          * uninteresting lines.  Connect such groups to give them a
 510          * bit of context.
 511          *
 512          * We first start from what the interesting() function says,
 513          * and mark them with "mark", and paint context lines with the
 514          * mark.  So interesting() would still say false for such context
 515          * lines but they are treated as "interesting" in the end.
 516          */
 517         i = find_next(sline, mark, 0, cnt, 0);
 518         if (cnt < i)
 519                 return 0;
 520
 521         while (i <= cnt) {
 522                 unsigned long j = (context < i) ? (i - context) : 0;
 523                 unsigned long k;
 524
 525                 /* Paint a few lines before the first interesting line. */
 526                 while (j < i) {
 527                         if (!(sline[j].flag & mark))
 528                                 sline[j].flag |= no_pre_delete;
 529                         sline[j++].flag |= mark;
 530                 }
 531
 532         again:
 533                 /* we know up to i is to be included.  where does the
 534                  * next uninteresting one start?
 535                  */
 536                 j = find_next(sline, mark, i, cnt, 1);
 537                 if (cnt < j)
 538                         break; /* the rest are all interesting */
 539
 540                 /* lookahead context lines */
 541                 k = find_next(sline, mark, j, cnt, 0);
 542                 j = adjust_hunk_tail(sline, all_mask, i, j);
 543
 544                 if (k < j + context) {
 545                         /* k is interesting and [j,k) are not, but
 546                          * paint them interesting because the gap is small.
 547                          */
 548                         while (j < k)
 549                                 sline[j++].flag |= mark;
 550                         i = k;
 551                         goto again;
 552                 }
 553
 554                 /* j is the first uninteresting line and there is
 555                  * no overlap beyond it within context lines.  Paint
 556                  * the trailing edge a bit.
 557                  */
 558                 i = k;
 559                 k = (j + context < cnt+1) ? j + context : cnt+1;
 560                 while (j < k)
 561                         sline[j++].flag |= mark;
 562         }
 563         return 1;
 564 }
 565
 566 static int make_hunks(struct sline *sline, unsigned long cnt,
 567                        int num_parent, int dense)
 568 {
 569         unsigned long all_mask = (1UL<<num_parent) - 1;
 570         unsigned long mark = (1UL<<num_parent);
 571         unsigned long i;
 572         int has_interesting = 0;
 573
 574         for (i = 0; i <= cnt; i++) {
 575                 if (interesting(&sline[i], all_mask))
 576                         sline[i].flag |= mark;
 577                 else
 578                         sline[i].flag &= ~mark;
 579         }
 580         if (!dense)
 581                 return give_context(sline, cnt, num_parent);
 582
 583         /* Look at each hunk, and if we have changes from only one
 584          * parent, or the changes are the same from all but one
 585          * parent, mark that uninteresting.
 586          */
 587         i = 0;
 588         while (i <= cnt) {
 589                 unsigned long j, hunk_begin, hunk_end;
 590                 unsigned long same_diff;
 591                 while (i <= cnt && !(sline[i].flag & mark))
 592                         i++;
 593                 if (cnt < i)
 594                         break; /* No more interesting hunks */
 595                 hunk_begin = i;
 596                 for (j = i + 1; j <= cnt; j++) {
 597                         if (!(sline[j].flag & mark)) {
 598                                 /* Look beyond the end to see if there
 599                                  * is an interesting line after this
 600                                  * hunk within context span.
 601                                  */
 602                                 unsigned long la; /* lookahead */
 603                                 int contin = 0;
 604                                 la = adjust_hunk_tail(sline, all_mask,
 605                                                      hunk_begin, j);
 606                                 la = (la + context < cnt + 1) ?
 607                                         (la + context) : cnt + 1;
 608                                 while (la && j <= --la) {
 609                                         if (sline[la].flag & mark) {
 610                                                 contin = 1;
 611                                                 break;
 612                                         }
 613                                 }
 614                                 if (!contin)
 615                                         break;
 616                                 j = la;
 617                         }
 618                 }
 619                 hunk_end = j;
 620
 621                 /* [i..hunk_end) are interesting.  Now is it really
 622                  * interesting?  We check if there are only two versions
 623                  * and the result matches one of them.  That is, we look
 624                  * at:
 625                  *   (+) line, which records lines added to which parents;
 626                  *       this line appears in the result.
 627                  *   (-) line, which records from what parents the line
 628                  *       was removed; this line does not appear in the result.
 629                  * then check the set of parents the result has difference
 630                  * from, from all lines.  If there are lines that has
 631                  * different set of parents that the result has differences
 632                  * from, that means we have more than two versions.
 633                  *
 634                  * Even when we have only two versions, if the result does
 635                  * not match any of the parents, the it should be considered
 636                  * interesting.  In such a case, we would have all '+' line.
 637                  * After passing the above "two versions" test, that would
 638                  * appear as "the same set of parents" to be "all parents".
 639                  */
 640                 same_diff = 0;
 641                 has_interesting = 0;
 642                 for (j = i; j < hunk_end && !has_interesting; j++) {
 643                         unsigned long this_diff = sline[j].flag & all_mask;
 644                         struct lline *ll = sline[j].lost;
 645                         if (this_diff) {
 646                                 /* This has some changes.  Is it the
 647                                  * same as others?
 648                                  */
 649                                 if (!same_diff)
 650                                         same_diff = this_diff;
 651                                 else if (same_diff != this_diff) {
 652                                         has_interesting = 1;
 653                                         break;
 654                                 }
 655                         }
 656                         while (ll && !has_interesting) {
 657                                 /* Lost this line from these parents;
 658                                  * who are they?  Are they the same?
 659                                  */
 660                                 this_diff = ll->parent_map;
 661                                 if (!same_diff)
 662                                         same_diff = this_diff;
 663                                 else if (same_diff != this_diff) {
 664                                         has_interesting = 1;
 665                                 }
 666                                 ll = ll->next;
 667                         }
 668                 }
 669
 670                 if (!has_interesting && same_diff != all_mask) {
 671                         /* This hunk is not that interesting after all */
 672                         for (j = hunk_begin; j < hunk_end; j++)
 673                                 sline[j].flag &= ~mark;
 674                 }
 675                 i = hunk_end;
 676         }
 677
 678         has_interesting = give_context(sline, cnt, num_parent);
 679         return has_interesting;
 680 }
 681
 682 static void show_parent_lno(struct sline *sline, unsigned long l0, unsigned long l1, int n, unsigned long null_context)
 683 {
 684         l0 = sline[l0].p_lno[n];
 685         l1 = sline[l1].p_lno[n];
 686         printf(" -%lu,%lu", l0, l1-l0-null_context);
 687 }
 688
 689 static int hunk_comment_line(const char *bol)
 690 {
 691         int ch;
 692
 693         if (!bol)
 694                 return 0;
 695         ch = *bol & 0xff;
 696         return (isalpha(ch) || ch == '_' || ch == '$');
 697 }
 698
 699 static void show_line_to_eol(const char *line, int len, const char *reset)
 700 {
 701         int saw_cr_at_eol = 0;
 702         if (len < 0)
 703                 len = strlen(line);
 704         saw_cr_at_eol = (len && line[len-1] == '\r');
 705
 706         printf("%.*s%s%s\n", len - saw_cr_at_eol, line,
 707                reset,
 708                saw_cr_at_eol ? "\r" : "");
 709 }
 710
 711 static void dump_sline(struct sline *sline, const char *line_prefix,
 712                        unsigned long cnt, int num_parent,
 713                        int use_color, int result_deleted)
 714 {
 715         unsigned long mark = (1UL<<num_parent);
 716         unsigned long no_pre_delete = (2UL<<num_parent);
 717         int i;
 718         unsigned long lno = 0;
 719         const char *c_frag = diff_get_color(use_color, DIFF_FRAGINFO);
 720         const char *c_func = diff_get_color(use_color, DIFF_FUNCINFO);
 721         const char *c_new = diff_get_color(use_color, DIFF_FILE_NEW);
 722         const char *c_old = diff_get_color(use_color, DIFF_FILE_OLD);
 723         const char *c_plain = diff_get_color(use_color, DIFF_PLAIN);
 724         const char *c_reset = diff_get_color(use_color, DIFF_RESET);
 725
 726         if (result_deleted)
 727                 return; /* result deleted */
 728
 729         while (1) {
 730                 unsigned long hunk_end;
 731                 unsigned long rlines;
 732                 const char *hunk_comment = NULL;
 733                 unsigned long null_context = 0;
 734
 735                 while (lno <= cnt && !(sline[lno].flag & mark)) {
 736                         if (hunk_comment_line(sline[lno].bol))
 737                                 hunk_comment = sline[lno].bol;
 738                         lno++;
 739                 }
 740                 if (cnt < lno)
 741                         break;
 742                 else {
 743                         for (hunk_end = lno + 1; hunk_end <= cnt; hunk_end++)
 744                                 if (!(sline[hunk_end].flag & mark))
 745                                         break;
 746                 }
 747                 rlines = hunk_end - lno;
 748                 if (cnt < hunk_end)
 749                         rlines--; /* pointing at the last delete hunk */
 750
 751                 if (!context) {
 752                         /*
 753                          * Even when running with --unified=0, all
 754                          * lines in the hunk needs to be processed in
 755                          * the loop below in order to show the
 756                          * deletion recorded in lost_head.  However,
 757                          * we do not want to show the resulting line
 758                          * with all blank context markers in such a
 759                          * case.  Compensate.
 760                          */
 761                         unsigned long j;
 762                         for (j = lno; j < hunk_end; j++)
 763                                 if (!(sline[j].flag & (mark-1)))
 764                                         null_context++;
 765                         rlines -= null_context;
 766                 }
 767
 768                 printf("%s%s", line_prefix, c_frag);
 769                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 770                 for (i = 0; i < num_parent; i++)
 771                         show_parent_lno(sline, lno, hunk_end, i, null_context);
 772                 printf(" +%lu,%lu ", lno+1, rlines);
 773                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 774
 775                 if (hunk_comment) {
 776                         int comment_end = 0;
 777                         for (i = 0; i < 40; i++) {
 778                                 int ch = hunk_comment[i] & 0xff;
 779                                 if (!ch || ch == '\n')
 780                                         break;
 781                                 if (!isspace(ch))
 782                                     comment_end = i;
 783                         }
 784                         if (comment_end)
 785                                 printf("%s%s %s%s", c_reset,
 786                                                     c_plain, c_reset,
 787                                                     c_func);
 788                         for (i = 0; i < comment_end; i++)
 789                                 putchar(hunk_comment[i]);
 790                 }
 791
 792                 printf("%s\n", c_reset);
 793                 while (lno < hunk_end) {
 794                         struct lline *ll;
 795                         int j;
 796                         unsigned long p_mask;
 797                         struct sline *sl = &sline[lno++];
 798                         ll = (sl->flag & no_pre_delete) ? NULL : sl->lost;
 799                         while (ll) {
 800                                 printf("%s%s", line_prefix, c_old);
 801                                 for (j = 0; j < num_parent; j++) {
 802                                         if (ll->parent_map & (1UL<<j))
 803                                                 putchar('-');
 804                                         else
 805                                                 putchar(' ');
 806                                 }
 807                                 show_line_to_eol(ll->line, -1, c_reset);
 808                                 ll = ll->next;
 809                         }
 810                         if (cnt < lno)
 811                                 break;
 812                         p_mask = 1;
 813                         fputs(line_prefix, stdout);
 814                         if (!(sl->flag & (mark-1))) {
 815                                 /*
 816                                  * This sline was here to hang the
 817                                  * lost lines in front of it.
 818                                  */
 819                                 if (!context)
 820                                         continue;
 821                                 fputs(c_plain, stdout);
 822                         }
 823                         else
 824                                 fputs(c_new, stdout);
 825                         for (j = 0; j < num_parent; j++) {
 826                                 if (p_mask & sl->flag)
 827                                         putchar('+');
 828                                 else
 829                                         putchar(' ');
 830                                 p_mask <<= 1;
 831                         }
 832                         show_line_to_eol(sl->bol, sl->len, c_reset);
 833                 }
 834         }
 835 }
 836
 837 static void reuse_combine_diff(struct sline *sline, unsigned long cnt,
 838                                int i, int j)
 839 {
 840         /* We have already examined parent j and we know parent i
 841          * and parent j are the same, so reuse the combined result
 842          * of parent j for parent i.
 843          */
 844         unsigned long lno, imask, jmask;
 845         imask = (1UL<<i);
 846         jmask = (1UL<<j);
 847
 848         for (lno = 0; lno <= cnt; lno++) {
 849                 struct lline *ll = sline->lost;
 850                 sline->p_lno[i] = sline->p_lno[j];
 851                 while (ll) {
 852                         if (ll->parent_map & jmask)
 853                                 ll->parent_map |= imask;
 854                         ll = ll->next;
 855                 }
 856                 if (sline->flag & jmask)
 857                         sline->flag |= imask;
 858                 sline++;
 859         }
 860         /* the overall size of the file (sline[cnt]) */
 861         sline->p_lno[i] = sline->p_lno[j];
 862 }
 863
 864 static void dump_quoted_path(const char *head,
 865                              const char *prefix,
 866                              const char *path,
 867                              const char *line_prefix,
 868                              const char *c_meta, const char *c_reset)
 869 {
 870         static struct strbuf buf = STRBUF_INIT;
 871
 872         strbuf_reset(&buf);
 873         strbuf_addstr(&buf, line_prefix);
 874         strbuf_addstr(&buf, c_meta);
 875         strbuf_addstr(&buf, head);
 876         quote_two_c_style(&buf, prefix, path, 0);
 877         strbuf_addstr(&buf, c_reset);
 878         puts(buf.buf);
 879 }
 880
 881 static void show_combined_header(struct combine_diff_path *elem,
 882                                  int num_parent,
 883                                  int dense,
 884                                  struct rev_info *rev,
 885                                  const char *line_prefix,
 886                                  int mode_differs,
 887                                  int show_file_header)
 888 {
 889         struct diff_options *opt = &rev->diffopt;
 890         int abbrev = DIFF_OPT_TST(opt, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
 891         const char *a_prefix = opt->a_prefix ? opt->a_prefix : "a/";
 892         const char *b_prefix = opt->b_prefix ? opt->b_prefix : "b/";
 893         const char *c_meta = diff_get_color_opt(opt, DIFF_METAINFO);
 894         const char *c_reset = diff_get_color_opt(opt, DIFF_RESET);
 895         const char *abb;
 896         int added = 0;
 897         int deleted = 0;
 898         int i;
 899
 900         if (rev->loginfo && !rev->no_commit_id)
 901                 show_log(rev);
 902
 903         dump_quoted_path(dense ? "diff --cc " : "diff --combined ",
 904                          "", elem->path, line_prefix, c_meta, c_reset);
 905         printf("%s%sindex ", line_prefix, c_meta);
 906         for (i = 0; i < num_parent; i++) {
 907                 abb = find_unique_abbrev(elem->parent[i].sha1,
 908                                          abbrev);
 909                 printf("%s%s", i ? "," : "", abb);
 910         }
 911         abb = find_unique_abbrev(elem->sha1, abbrev);
 912         printf("..%s%s\n", abb, c_reset);
 913
 914         if (mode_differs) {
 915                 deleted = !elem->mode;
 916
 917                 /* We say it was added if nobody had it */
 918                 added = !deleted;
 919                 for (i = 0; added && i < num_parent; i++)
 920                         if (elem->parent[i].status !=
 921                             DIFF_STATUS_ADDED)
 922                                 added = 0;
 923                 if (added)
 924                         printf("%s%snew file mode %06o",
 925                                line_prefix, c_meta, elem->mode);
 926                 else {
 927                         if (deleted)
 928                                 printf("%s%sdeleted file ",
 929                                        line_prefix, c_meta);
 930                         printf("mode ");
 931                         for (i = 0; i < num_parent; i++) {
 932                                 printf("%s%06o", i ? "," : "",
 933                                        elem->parent[i].mode);
 934                         }
 935                         if (elem->mode)
 936                                 printf("..%06o", elem->mode);
 937                 }
 938                 printf("%s\n", c_reset);
 939         }
 940
 941         if (!show_file_header)
 942                 return;
 943
 944         if (added)
 945                 dump_quoted_path("--- ", "", "/dev/null",
 946                                  line_prefix, c_meta, c_reset);
 947         else
 948                 dump_quoted_path("--- ", a_prefix, elem->path,
 949                                  line_prefix, c_meta, c_reset);
 950         if (deleted)
 951                 dump_quoted_path("+++ ", "", "/dev/null",
 952                                  line_prefix, c_meta, c_reset);
 953         else
 954                 dump_quoted_path("+++ ", b_prefix, elem->path,
 955                                  line_prefix, c_meta, c_reset);
 956 }
 957
 958 static void show_patch_diff(struct combine_diff_path *elem, int num_parent,
 959                             int dense, int working_tree_file,
 960                             struct rev_info *rev)
 961 {
 962         struct diff_options *opt = &rev->diffopt;
 963         unsigned long result_size, cnt, lno;
 964         int result_deleted = 0;
 965         char *result, *cp;
 966         struct sline *sline; /* survived lines */
 967         int mode_differs = 0;
 968         int i, show_hunks;
 969         mmfile_t result_file;
 970         struct userdiff_driver *userdiff;
 971         struct userdiff_driver *textconv = NULL;
 972         int is_binary;
 973         const char *line_prefix = diff_line_prefix(opt);
 974
 975         context = opt->context;
 976         userdiff = userdiff_find_by_path(elem->path);
 977         if (!userdiff)
 978                 userdiff = userdiff_find_by_name("default");
 979         if (DIFF_OPT_TST(opt, ALLOW_TEXTCONV))
 980                 textconv = userdiff_get_textconv(userdiff);
 981
 982         /* Read the result of merge first */
 983         if (!working_tree_file)
 984                 result = grab_blob(elem->sha1, elem->mode, &result_size,
 985                                    textconv, elem->path);
 986         else {
 987                 /* Used by diff-tree to read from the working tree */
 988                 struct stat st;
 989                 int fd = -1;
 990
 991                 if (lstat(elem->path, &st) < 0)
 992                         goto deleted_file;
 993
 994                 if (S_ISLNK(st.st_mode)) {
 995                         struct strbuf buf = STRBUF_INIT;
 996
 997                         if (strbuf_readlink(&buf, elem->path, st.st_size) < 0) {
 998                                 error("readlink(%s): %s", elem->path,
 999                                       strerror(errno));
1000                                 return;
1001                         }
1002                         result_size = buf.len;
1003                         result = strbuf_detach(&buf, NULL);
1004                         elem->mode = canon_mode(st.st_mode);
1005                 } else if (S_ISDIR(st.st_mode)) {
1006                         unsigned char sha1[20];
1007                         if (resolve_gitlink_ref(elem->path, "HEAD", sha1) < 0)
1008                                 result = grab_blob(elem->sha1, elem->mode,
1009                                                    &result_size, NULL, NULL);
1010                         else
1011                                 result = grab_blob(sha1, elem->mode,
1012                                                    &result_size, NULL, NULL);
1013                 } else if (textconv) {
1014                         struct diff_filespec *df = alloc_filespec(elem->path);
1015                         fill_filespec(df, null_sha1, 0, st.st_mode);
1016                         result_size = fill_textconv(textconv, df, &result);
1017                         free_filespec(df);
1018                 } else if (0 <= (fd = open(elem->path, O_RDONLY))) {
1019                         size_t len = xsize_t(st.st_size);
1020                         ssize_t done;
1021                         int is_file, i;
1022
1023                         elem->mode = canon_mode(st.st_mode);
1024                         /* if symlinks don't work, assume symlink if all parents
1025                          * are symlinks
1026                          */
1027                         is_file = has_symlinks;
1028                         for (i = 0; !is_file && i < num_parent; i++)
1029                                 is_file = !S_ISLNK(elem->parent[i].mode);
1030                         if (!is_file)
1031                                 elem->mode = canon_mode(S_IFLNK);
1032
1033                         result_size = len;
1034                         result = xmalloc(len + 1);
1035
1036                         done = read_in_full(fd, result, len);
1037                         if (done < 0)
1038                                 die_errno("read error '%s'", elem->path);
1039                         else if (done < len)
1040                                 die("early EOF '%s'", elem->path);
1041
1042                         result[len] = 0;
1043
1044                         /* If not a fake symlink, apply filters, e.g. autocrlf */
1045                         if (is_file) {
1046                                 struct strbuf buf = STRBUF_INIT;
1047
1048                                 if (convert_to_git(elem->path, result, len, &buf, safe_crlf)) {
1049                                         free(result);
1050                                         result = strbuf_detach(&buf, &len);
1051                                         result_size = len;
1052                                 }
1053                         }
1054                 }
1055                 else {
1056                 deleted_file:
1057                         result_deleted = 1;
1058                         result_size = 0;
1059                         elem->mode = 0;
1060                         result = xcalloc(1, 1);
1061                 }
1062
1063                 if (0 <= fd)
1064                         close(fd);
1065         }
1066
1067         for (i = 0; i < num_parent; i++) {
1068                 if (elem->parent[i].mode != elem->mode) {
1069                         mode_differs = 1;
1070                         break;
1071                 }
1072         }
1073
1074         if (textconv)
1075                 is_binary = 0;
1076         else if (userdiff->binary != -1)
1077                 is_binary = userdiff->binary;
1078         else {
1079                 is_binary = buffer_is_binary(result, result_size);
1080                 for (i = 0; !is_binary && i < num_parent; i++) {
1081                         char *buf;
1082                         unsigned long size;
1083                         buf = grab_blob(elem->parent[i].sha1,
1084                                         elem->parent[i].mode,
1085                                         &size, NULL, NULL);
1086                         if (buffer_is_binary(buf, size))
1087                                 is_binary = 1;
1088                         free(buf);
1089                 }
1090         }
1091         if (is_binary) {
1092                 show_combined_header(elem, num_parent, dense, rev,
1093                                      line_prefix, mode_differs, 0);
1094                 printf("Binary files differ\n");
1095                 free(result);
1096                 return;
1097         }
1098
1099         for (cnt = 0, cp = result; cp < result + result_size; cp++) {
1100                 if (*cp == '\n')
1101                         cnt++;
1102         }
1103         if (result_size && result[result_size-1] != '\n')
1104                 cnt++; /* incomplete line */
1105
1106         sline = xcalloc(cnt+2, sizeof(*sline));
1107         sline[0].bol = result;
1108         for (lno = 0, cp = result; cp < result + result_size; cp++) {
1109                 if (*cp == '\n') {
1110                         sline[lno].len = cp - sline[lno].bol;
1111                         lno++;
1112                         if (lno < cnt)
1113                                 sline[lno].bol = cp + 1;
1114                 }
1115         }
1116         if (result_size && result[result_size-1] != '\n')
1117                 sline[cnt-1].len = result_size - (sline[cnt-1].bol - result);
1118
1119         result_file.ptr = result;
1120         result_file.size = result_size;
1121
1122         /* Even p_lno[cnt+1] is valid -- that is for the end line number
1123          * for deletion hunk at the end.
1124          */
1125         sline[0].p_lno = xcalloc((cnt+2) * num_parent, sizeof(unsigned long));
1126         for (lno = 0; lno <= cnt; lno++)
1127                 sline[lno+1].p_lno = sline[lno].p_lno + num_parent;
1128
1129         for (i = 0; i < num_parent; i++) {
1130                 int j;
1131                 for (j = 0; j < i; j++) {
1132                         if (!hashcmp(elem->parent[i].sha1,
1133                                      elem->parent[j].sha1)) {
1134                                 reuse_combine_diff(sline, cnt, i, j);
1135                                 break;
1136                         }
1137                 }
1138                 if (i <= j)
1139                         combine_diff(elem->parent[i].sha1,
1140                                      elem->parent[i].mode,
1141                                      &result_file, sline,
1142                                      cnt, i, num_parent, result_deleted,
1143                                      textconv, elem->path, opt->xdl_opts);
1144         }
1145
1146         show_hunks = make_hunks(sline, cnt, num_parent, dense);
1147
1148         if (show_hunks || mode_differs || working_tree_file) {
1149                 show_combined_header(elem, num_parent, dense, rev,
1150                                      line_prefix, mode_differs, 1);
1151                 dump_sline(sline, line_prefix, cnt, num_parent,
1152                            opt->use_color, result_deleted);
1153         }
1154         free(result);
1155
1156         for (lno = 0; lno < cnt; lno++) {
1157                 if (sline[lno].lost) {
1158                         struct lline *ll = sline[lno].lost;
1159                         while (ll) {
1160                                 struct lline *tmp = ll;
1161                                 ll = ll->next;
1162                                 free(tmp);
1163                         }
1164                 }
1165         }
1166         free(sline[0].p_lno);
1167         free(sline);
1168 }
1169
1170 static void show_raw_diff(struct combine_diff_path *p, int num_parent, struct rev_info *rev)
1171 {
1172         struct diff_options *opt = &rev->diffopt;
1173         int line_termination, inter_name_termination, i;
1174         const char *line_prefix = diff_line_prefix(opt);
1175
1176         line_termination = opt->line_termination;
1177         inter_name_termination = '\t';
1178         if (!line_termination)
1179                 inter_name_termination = 0;
1180
1181         if (rev->loginfo && !rev->no_commit_id)
1182                 show_log(rev);
1183
1184
1185         if (opt->output_format & DIFF_FORMAT_RAW) {
1186                 printf("%s", line_prefix);
1187
1188                 /* As many colons as there are parents */
1189                 for (i = 0; i < num_parent; i++)
1190                         putchar(':');
1191
1192                 /* Show the modes */
1193                 for (i = 0; i < num_parent; i++)
1194                         printf("%06o ", p->parent[i].mode);
1195                 printf("%06o", p->mode);
1196
1197                 /* Show sha1's */
1198                 for (i = 0; i < num_parent; i++)
1199                         printf(" %s", diff_unique_abbrev(p->parent[i].sha1,
1200                                                          opt->abbrev));
1201                 printf(" %s ", diff_unique_abbrev(p->sha1, opt->abbrev));
1202         }
1203
1204         if (opt->output_format & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS)) {
1205                 for (i = 0; i < num_parent; i++)
1206                         putchar(p->parent[i].status);
1207                 putchar(inter_name_termination);
1208         }
1209
1210         write_name_quoted(p->path, stdout, line_termination);
1211 }
1212
1213 /*
1214  * The result (p->elem) is from the working tree and their
1215  * parents are typically from multiple stages during a merge
1216  * (i.e. diff-files) or the state in HEAD and in the index
1217  * (i.e. diff-index).
1218  */
1219 void show_combined_diff(struct combine_diff_path *p,
1220                        int num_parent,
1221                        int dense,
1222                        struct rev_info *rev)
1223 {
1224         struct diff_options *opt = &rev->diffopt;
1225
1226         if (opt->output_format & (DIFF_FORMAT_RAW |
1227                                   DIFF_FORMAT_NAME |
1228                                   DIFF_FORMAT_NAME_STATUS))
1229                 show_raw_diff(p, num_parent, rev);
1230         else if (opt->output_format & DIFF_FORMAT_PATCH)
1231                 show_patch_diff(p, num_parent, dense, 1, rev);
1232 }
1233
1234 static void free_combined_pair(struct diff_filepair *pair)
1235 {
1236         free(pair->two);
1237         free(pair);
1238 }
1239
1240 /*
1241  * A combine_diff_path expresses N parents on the LHS against 1 merge
1242  * result. Synthesize a diff_filepair that has N entries on the "one"
1243  * side and 1 entry on the "two" side.
1244  *
1245  * In the future, we might want to add more data to combine_diff_path
1246  * so that we can fill fields we are ignoring (most notably, size) here,
1247  * but currently nobody uses it, so this should suffice for now.
1248  */
1249 static struct diff_filepair *combined_pair(struct combine_diff_path *p,
1250                                            int num_parent)
1251 {
1252         int i;
1253         struct diff_filepair *pair;
1254         struct diff_filespec *pool;
1255
1256         pair = xmalloc(sizeof(*pair));
1257         pool = xcalloc(num_parent + 1, sizeof(struct diff_filespec));
1258         pair->one = pool + 1;
1259         pair->two = pool;
1260
1261         for (i = 0; i < num_parent; i++) {
1262                 pair->one[i].path = p->path;
1263                 pair->one[i].mode = p->parent[i].mode;
1264                 hashcpy(pair->one[i].sha1, p->parent[i].sha1);
1265                 pair->one[i].sha1_valid = !is_null_sha1(p->parent[i].sha1);
1266                 pair->one[i].has_more_entries = 1;
1267         }
1268         pair->one[num_parent - 1].has_more_entries = 0;
1269
1270         pair->two->path = p->path;
1271         pair->two->mode = p->mode;
1272         hashcpy(pair->two->sha1, p->sha1);
1273         pair->two->sha1_valid = !is_null_sha1(p->sha1);
1274         return pair;
1275 }
1276
1277 static void handle_combined_callback(struct diff_options *opt,
1278                                      struct combine_diff_path *paths,
1279                                      int num_parent,
1280                                      int num_paths)
1281 {
1282         struct combine_diff_path *p;
1283         struct diff_queue_struct q;
1284         int i;
1285
1286         q.queue = xcalloc(num_paths, sizeof(struct diff_filepair *));
1287         q.alloc = num_paths;
1288         q.nr = num_paths;
1289         for (i = 0, p = paths; p; p = p->next)
1290                 q.queue[i++] = combined_pair(p, num_parent);
1291         opt->format_callback(&q, opt, opt->format_callback_data);
1292         for (i = 0; i < num_paths; i++)
1293                 free_combined_pair(q.queue[i]);
1294         free(q.queue);
1295 }
1296
1297 static const char *path_path(void *obj)
1298 {
1299         struct combine_diff_path *path = (struct combine_diff_path *)obj;
1300
1301         return path->path;
1302 }
1303
1304
1305 /* find set of paths that every parent touches */
1306 static struct combine_diff_path *find_paths_generic(const unsigned char *sha1,
1307         const struct sha1_array *parents, struct diff_options *opt)
1308 {
1309         struct combine_diff_path *paths = NULL;
1310         int i, num_parent = parents->nr;
1311
1312         int output_format = opt->output_format;
1313         const char *orderfile = opt->orderfile;
1314
1315         opt->output_format = DIFF_FORMAT_NO_OUTPUT;
1316         /* tell diff_tree to emit paths in sorted (=tree) order */
1317         opt->orderfile = NULL;
1318
1319         /* D(A,P1...Pn) = D(A,P1) ^ ... ^ D(A,Pn)  (wrt paths) */
1320         for (i = 0; i < num_parent; i++) {
1321                 /*
1322                  * show stat against the first parent even when doing
1323                  * combined diff.
1324                  */
1325                 int stat_opt = (output_format &
1326                                 (DIFF_FORMAT_NUMSTAT|DIFF_FORMAT_DIFFSTAT));
1327                 if (i == 0 && stat_opt)
1328                         opt->output_format = stat_opt;
1329                 else
1330                         opt->output_format = DIFF_FORMAT_NO_OUTPUT;
1331                 diff_tree_sha1(parents->sha1[i], sha1, "", opt);
1332                 diffcore_std(opt);
1333                 paths = intersect_paths(paths, i, num_parent);
1334
1335                 /* if showing diff, show it in requested order */
1336                 if (opt->output_format != DIFF_FORMAT_NO_OUTPUT &&
1337                     orderfile) {
1338                         diffcore_order(orderfile);
1339                 }
1340
1341                 diff_flush(opt);
1342         }
1343
1344         opt->output_format = output_format;
1345         opt->orderfile = orderfile;
1346         return paths;
1347 }
1348
1349
1350 /*
1351  * find set of paths that everybody touches, assuming diff is run without
1352  * rename/copy detection, etc, comparing all trees simultaneously (= faster).
1353  */
1354 static struct combine_diff_path *find_paths_multitree(
1355         const unsigned char *sha1, const struct sha1_array *parents,
1356         struct diff_options *opt)
1357 {
1358         int i, nparent = parents->nr;
1359         const unsigned char **parents_sha1;
1360         struct combine_diff_path paths_head;
1361         struct strbuf base;
1362
1363         parents_sha1 = xmalloc(nparent * sizeof(parents_sha1[0]));
1364         for (i = 0; i < nparent; i++)
1365                 parents_sha1[i] = parents->sha1[i];
1366
1367         /* fake list head, so worker can assume it is non-NULL */
1368         paths_head.next = NULL;
1369
1370         strbuf_init(&base, PATH_MAX);
1371         diff_tree_paths(&paths_head, sha1, parents_sha1, nparent, &base, opt);
1372
1373         strbuf_release(&base);
1374         free(parents_sha1);
1375         return paths_head.next;
1376 }
1377
1378
1379 void diff_tree_combined(const unsigned char *sha1,
1380                         const struct sha1_array *parents,
1381                         int dense,
1382                         struct rev_info *rev)
1383 {
1384         struct diff_options *opt = &rev->diffopt;
1385         struct diff_options diffopts;
1386         struct combine_diff_path *p, *paths;
1387         int i, num_paths, needsep, show_log_first, num_parent = parents->nr;
1388         int need_generic_pathscan;
1389
1390         /* nothing to do, if no parents */
1391         if (!num_parent)
1392                 return;
1393
1394         show_log_first = !!rev->loginfo && !rev->no_commit_id;
1395         needsep = 0;
1396         if (show_log_first) {
1397                 show_log(rev);
1398
1399                 if (rev->verbose_header && opt->output_format &&
1400                     opt->output_format != DIFF_FORMAT_NO_OUTPUT)
1401                         printf("%s%c", diff_line_prefix(opt),
1402                                opt->line_termination);
1403         }
1404
1405         diffopts = *opt;
1406         copy_pathspec(&diffopts.pathspec, &opt->pathspec);
1407         DIFF_OPT_SET(&diffopts, RECURSIVE);
1408         DIFF_OPT_CLR(&diffopts, ALLOW_EXTERNAL);
1409
1410         /* find set of paths that everybody touches
1411          *
1412          * NOTE
1413          *
1414          * Diffcore transformations are bound to diff_filespec and logic
1415          * comparing two entries - i.e. they do not apply directly to combine
1416          * diff.
1417          *
1418          * If some of such transformations is requested - we launch generic
1419          * path scanning, which works significantly slower compared to
1420          * simultaneous all-trees-in-one-go scan in find_paths_multitree().
1421          *
1422          * TODO some of the filters could be ported to work on
1423          * combine_diff_paths - i.e. all functionality that skips paths, so in
1424          * theory, we could end up having only multitree path scanning.
1425          *
1426          * NOTE please keep this semantically in sync with diffcore_std()
1427          */
1428         need_generic_pathscan = opt->skip_stat_unmatch  ||
1429                         DIFF_OPT_TST(opt, FOLLOW_RENAMES)       ||
1430                         opt->break_opt != -1    ||
1431                         opt->detect_rename      ||
1432                         opt->pickaxe            ||
1433                         opt->filter;
1434
1435
1436         if (need_generic_pathscan) {
1437                 /*
1438                  * NOTE generic case also handles --stat, as it computes
1439                  * diff(sha1,parent_i) for all i to do the job, specifically
1440                  * for parent0.
1441                  */
1442                 paths = find_paths_generic(sha1, parents, &diffopts);
1443         }
1444         else {
1445                 int stat_opt;
1446                 paths = find_paths_multitree(sha1, parents, &diffopts);
1447
1448                 /*
1449                  * show stat against the first parent even
1450                  * when doing combined diff.
1451                  */
1452                 stat_opt = (opt->output_format &
1453                                 (DIFF_FORMAT_NUMSTAT|DIFF_FORMAT_DIFFSTAT));
1454                 if (stat_opt) {
1455                         diffopts.output_format = stat_opt;
1456
1457                         diff_tree_sha1(parents->sha1[0], sha1, "", &diffopts);
1458                         diffcore_std(&diffopts);
1459                         if (opt->orderfile)
1460                                 diffcore_order(opt->orderfile);
1461                         diff_flush(&diffopts);
1462                 }
1463         }
1464
1465         /* find out number of surviving paths */
1466         for (num_paths = 0, p = paths; p; p = p->next)
1467                 num_paths++;
1468
1469         /* order paths according to diffcore_order */
1470         if (opt->orderfile && num_paths) {
1471                 struct obj_order *o;
1472
1473                 o = xmalloc(sizeof(*o) * num_paths);
1474                 for (i = 0, p = paths; p; p = p->next, i++)
1475                         o[i].obj = p;
1476                 order_objects(opt->orderfile, path_path, o, num_paths);
1477                 for (i = 0; i < num_paths - 1; i++) {
1478                         p = o[i].obj;
1479                         p->next = o[i+1].obj;
1480                 }
1481
1482                 p = o[num_paths-1].obj;
1483                 p->next = NULL;
1484                 paths = o[0].obj;
1485                 free(o);
1486         }
1487
1488
1489         if (num_paths) {
1490                 if (opt->output_format & (DIFF_FORMAT_RAW |
1491                                           DIFF_FORMAT_NAME |
1492                                           DIFF_FORMAT_NAME_STATUS)) {
1493                         for (p = paths; p; p = p->next)
1494                                 show_raw_diff(p, num_parent, rev);
1495                         needsep = 1;
1496                 }
1497                 else if (opt->output_format &
1498                          (DIFF_FORMAT_NUMSTAT|DIFF_FORMAT_DIFFSTAT))
1499                         needsep = 1;
1500                 else if (opt->output_format & DIFF_FORMAT_CALLBACK)
1501                         handle_combined_callback(opt, paths, num_parent, num_paths);
1502
1503                 if (opt->output_format & DIFF_FORMAT_PATCH) {
1504                         if (needsep)
1505                                 printf("%s%c", diff_line_prefix(opt),
1506                                        opt->line_termination);
1507                         for (p = paths; p; p = p->next)
1508                                 show_patch_diff(p, num_parent, dense,
1509                                                 0, rev);
1510                 }
1511         }
1512
1513         /* Clean things up */
1514         while (paths) {
1515                 struct combine_diff_path *tmp = paths;
1516                 paths = paths->next;
1517                 free(tmp);
1518         }
1519
1520         free_pathspec(&diffopts.pathspec);
1521 }
1522
1523 void diff_tree_combined_merge(const struct commit *commit, int dense,
1524                               struct rev_info *rev)
1525 {
1526         struct commit_list *parent = get_saved_parents(rev, commit);
1527         struct sha1_array parents = SHA1_ARRAY_INIT;
1528
1529         while (parent) {
1530                 sha1_array_append(&parents, parent->item->object.sha1);
1531                 parent = parent->next;
1532         }
1533         diff_tree_combined(commit->object.sha1, &parents, dense, rev);
1534         sha1_array_clear(&parents);
1535 }