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 "log-tree.h"
   9
  10 static struct combine_diff_path *intersect_paths(struct combine_diff_path *curr, int n, int num_parent)
  11 {
  12         struct diff_queue_struct *q = &diff_queued_diff;
  13         struct combine_diff_path *p;
  14         int i;
  15
  16         if (!n) {
  17                 struct combine_diff_path *list = NULL, **tail = &list;
  18                 for (i = 0; i < q->nr; i++) {
  19                         int len;
  20                         const char *path;
  21                         if (diff_unmodified_pair(q->queue[i]))
  22                                 continue;
  23                         path = q->queue[i]->two->path;
  24                         len = strlen(path);
  25                         p = xmalloc(combine_diff_path_size(num_parent, len));
  26                         p->path = (char*) &(p->parent[num_parent]);
  27                         memcpy(p->path, path, len);
  28                         p->path[len] = 0;
  29                         p->len = len;
  30                         p->next = NULL;
  31                         memset(p->parent, 0,
  32                                sizeof(p->parent[0]) * num_parent);
  33
  34                         memcpy(p->sha1, q->queue[i]->two->sha1, 20);
  35                         p->mode = q->queue[i]->two->mode;
  36                         memcpy(p->parent[n].sha1, q->queue[i]->one->sha1, 20);
  37                         p->parent[n].mode = q->queue[i]->one->mode;
  38                         p->parent[n].status = q->queue[i]->status;
  39                         *tail = p;
  40                         tail = &p->next;
  41                 }
  42                 return list;
  43         }
  44
  45         for (p = curr; p; p = p->next) {
  46                 int found = 0;
  47                 if (!p->len)
  48                         continue;
  49                 for (i = 0; i < q->nr; i++) {
  50                         const char *path;
  51                         int len;
  52
  53                         if (diff_unmodified_pair(q->queue[i]))
  54                                 continue;
  55                         path = q->queue[i]->two->path;
  56                         len = strlen(path);
  57                         if (len == p->len && !memcmp(path, p->path, len)) {
  58                                 found = 1;
  59                                 memcpy(p->parent[n].sha1,
  60                                        q->queue[i]->one->sha1, 20);
  61                                 p->parent[n].mode = q->queue[i]->one->mode;
  62                                 p->parent[n].status = q->queue[i]->status;
  63                                 break;
  64                         }
  65                 }
  66                 if (!found)
  67                         p->len = 0;
  68         }
  69         return curr;
  70 }
  71
  72 /* Lines lost from parent */
  73 struct lline {
  74         struct lline *next;
  75         int len;
  76         unsigned long parent_map;
  77         char line[FLEX_ARRAY];
  78 };
  79
  80 /* Lines surviving in the merge result */
  81 struct sline {
  82         struct lline *lost_head, **lost_tail;
  83         char *bol;
  84         int len;
  85         /* bit 0 up to (N-1) are on if the parent has this line (i.e.
  86          * we did not change it).
  87          * bit N is used for "interesting" lines, including context.
  88          */
  89         unsigned long flag;
  90         unsigned long *p_lno;
  91 };
  92
  93 static char *grab_blob(const unsigned char *sha1, unsigned long *size)
  94 {
  95         char *blob;
  96         char type[20];
  97         if (!memcmp(sha1, null_sha1, 20)) {
  98                 /* deleted blob */
  99                 *size = 0;
 100                 return xcalloc(1, 1);
 101         }
 102         blob = read_sha1_file(sha1, type, size);
 103         if (strcmp(type, blob_type))
 104                 die("object '%s' is not a blob!", sha1_to_hex(sha1));
 105         return blob;
 106 }
 107
 108 static void append_lost(struct sline *sline, int n, const char *line, int len)
 109 {
 110         struct lline *lline;
 111         unsigned long this_mask = (1UL<<n);
 112         if (line[len-1] == '\n')
 113                 len--;
 114
 115         /* Check to see if we can squash things */
 116         if (sline->lost_head) {
 117                 struct lline *last_one = NULL;
 118                 /* We cannot squash it with earlier one */
 119                 for (lline = sline->lost_head;
 120                      lline;
 121                      lline = lline->next)
 122                         if (lline->parent_map & this_mask)
 123                                 last_one = lline;
 124                 lline = last_one ? last_one->next : sline->lost_head;
 125                 while (lline) {
 126                         if (lline->len == len &&
 127                             !memcmp(lline->line, line, len)) {
 128                                 lline->parent_map |= this_mask;
 129                                 return;
 130                         }
 131                         lline = lline->next;
 132                 }
 133         }
 134
 135         lline = xmalloc(sizeof(*lline) + len + 1);
 136         lline->len = len;
 137         lline->next = NULL;
 138         lline->parent_map = this_mask;
 139         memcpy(lline->line, line, len);
 140         lline->line[len] = 0;
 141         *sline->lost_tail = lline;
 142         sline->lost_tail = &lline->next;
 143 }
 144
 145 struct combine_diff_state {
 146         struct xdiff_emit_state xm;
 147
 148         unsigned int lno;
 149         int ob, on, nb, nn;
 150         unsigned long nmask;
 151         int num_parent;
 152         int n;
 153         struct sline *sline;
 154         struct sline *lost_bucket;
 155 };
 156
 157 static void consume_line(void *state_, char *line, unsigned long len)
 158 {
 159         struct combine_diff_state *state = state_;
 160         if (5 < len && !memcmp("@@ -", line, 4)) {
 161                 if (parse_hunk_header(line, len,
 162                                       &state->ob, &state->on,
 163                                       &state->nb, &state->nn))
 164                         return;
 165                 state->lno = state->nb;
 166                 if (!state->nb)
 167                         /* @@ -1,2 +0,0 @@ to remove the
 168                          * first two lines...
 169                          */
 170                         state->nb = 1;
 171                 if (state->nn == 0)
 172                         /* @@ -X,Y +N,0 @@ removed Y lines
 173                          * that would have come *after* line N
 174                          * in the result.  Our lost buckets hang
 175                          * to the line after the removed lines,
 176                          */
 177                         state->lost_bucket = &state->sline[state->nb];
 178                 else
 179                         state->lost_bucket = &state->sline[state->nb-1];
 180                 if (!state->sline[state->nb-1].p_lno)
 181                         state->sline[state->nb-1].p_lno =
 182                                 xcalloc(state->num_parent,
 183                                         sizeof(unsigned long));
 184                 state->sline[state->nb-1].p_lno[state->n] = state->ob;
 185                 return;
 186         }
 187         if (!state->lost_bucket)
 188                 return; /* not in any hunk yet */
 189         switch (line[0]) {
 190         case '-':
 191                 append_lost(state->lost_bucket, state->n, line+1, len-1);
 192                 break;
 193         case '+':
 194                 state->sline[state->lno-1].flag |= state->nmask;
 195                 state->lno++;
 196                 break;
 197         }
 198 }
 199
 200 static void combine_diff(const unsigned char *parent, mmfile_t *result_file,
 201                          struct sline *sline, unsigned int cnt, int n,
 202                          int num_parent)
 203 {
 204         unsigned int p_lno, lno;
 205         unsigned long nmask = (1UL << n);
 206         xpparam_t xpp;
 207         xdemitconf_t xecfg;
 208         mmfile_t parent_file;
 209         xdemitcb_t ecb;
 210         struct combine_diff_state state;
 211         unsigned long sz;
 212
 213         if (!cnt)
 214                 return; /* result deleted */
 215
 216         parent_file.ptr = grab_blob(parent, &sz);
 217         parent_file.size = sz;
 218         xpp.flags = XDF_NEED_MINIMAL;
 219         xecfg.ctxlen = 0;
 220         xecfg.flags = 0;
 221         ecb.outf = xdiff_outf;
 222         ecb.priv = &state;
 223         memset(&state, 0, sizeof(state));
 224         state.xm.consume = consume_line;
 225         state.nmask = nmask;
 226         state.sline = sline;
 227         state.lno = 1;
 228         state.num_parent = num_parent;
 229         state.n = n;
 230
 231         xdl_diff(&parent_file, result_file, &xpp, &xecfg, &ecb);
 232         free(parent_file.ptr);
 233
 234         /* Assign line numbers for this parent.
 235          *
 236          * sline[lno].p_lno[n] records the first line number
 237          * (counting from 1) for parent N if the final hunk display
 238          * started by showing sline[lno] (possibly showing the lost
 239          * lines attached to it first).
 240          */
 241         for (lno = 0,  p_lno = 1; lno <= cnt; lno++) {
 242                 struct lline *ll;
 243                 sline[lno].p_lno[n] = p_lno;
 244
 245                 /* How many lines would this sline advance the p_lno? */
 246                 ll = sline[lno].lost_head;
 247                 while (ll) {
 248                         if (ll->parent_map & nmask)
 249                                 p_lno++; /* '-' means parent had it */
 250                         ll = ll->next;
 251                 }
 252                 if (lno < cnt && !(sline[lno].flag & nmask))
 253                         p_lno++; /* no '+' means parent had it */
 254         }
 255         sline[lno].p_lno[n] = p_lno; /* trailer */
 256 }
 257
 258 static unsigned long context = 3;
 259 static char combine_marker = '@';
 260
 261 static int interesting(struct sline *sline, unsigned long all_mask)
 262 {
 263         /* If some parents lost lines here, or if we have added to
 264          * some parent, it is interesting.
 265          */
 266         return ((sline->flag & all_mask) || sline->lost_head);
 267 }
 268
 269 static unsigned long adjust_hunk_tail(struct sline *sline,
 270                                       unsigned long all_mask,
 271                                       unsigned long hunk_begin,
 272                                       unsigned long i)
 273 {
 274         /* i points at the first uninteresting line.  If the last line
 275          * of the hunk was interesting only because it has some
 276          * deletion, then it is not all that interesting for the
 277          * purpose of giving trailing context lines.  This is because
 278          * we output '-' line and then unmodified sline[i-1] itself in
 279          * that case which gives us one extra context line.
 280          */
 281         if ((hunk_begin + 1 <= i) && !(sline[i-1].flag & all_mask))
 282                 i--;
 283         return i;
 284 }
 285
 286 static unsigned long find_next(struct sline *sline,
 287                                unsigned long mark,
 288                                unsigned long i,
 289                                unsigned long cnt,
 290                                int look_for_uninteresting)
 291 {
 292         /* We have examined up to i-1 and are about to look at i.
 293          * Find next interesting or uninteresting line.  Here,
 294          * "interesting" does not mean interesting(), but marked by
 295          * the give_context() function below (i.e. it includes context
 296          * lines that are not interesting to interesting() function
 297          * that are surrounded by interesting() ones.
 298          */
 299         while (i <= cnt)
 300                 if (look_for_uninteresting
 301                     ? !(sline[i].flag & mark)
 302                     : (sline[i].flag & mark))
 303                         return i;
 304                 else
 305                         i++;
 306         return i;
 307 }
 308
 309 static int give_context(struct sline *sline, unsigned long cnt, int num_parent)
 310 {
 311         unsigned long all_mask = (1UL<<num_parent) - 1;
 312         unsigned long mark = (1UL<<num_parent);
 313         unsigned long i;
 314
 315         /* Two groups of interesting lines may have a short gap of
 316          * uninteresting lines.  Connect such groups to give them a
 317          * bit of context.
 318          *
 319          * We first start from what the interesting() function says,
 320          * and mark them with "mark", and paint context lines with the
 321          * mark.  So interesting() would still say false for such context
 322          * lines but they are treated as "interesting" in the end.
 323          */
 324         i = find_next(sline, mark, 0, cnt, 0);
 325         if (cnt < i)
 326                 return 0;
 327
 328         while (i <= cnt) {
 329                 unsigned long j = (context < i) ? (i - context) : 0;
 330                 unsigned long k;
 331
 332                 /* Paint a few lines before the first interesting line. */
 333                 while (j < i)
 334                         sline[j++].flag |= mark;
 335
 336         again:
 337                 /* we know up to i is to be included.  where does the
 338                  * next uninteresting one start?
 339                  */
 340                 j = find_next(sline, mark, i, cnt, 1);
 341                 if (cnt < j)
 342                         break; /* the rest are all interesting */
 343
 344                 /* lookahead context lines */
 345                 k = find_next(sline, mark, j, cnt, 0);
 346                 j = adjust_hunk_tail(sline, all_mask, i, j);
 347
 348                 if (k < j + context) {
 349                         /* k is interesting and [j,k) are not, but
 350                          * paint them interesting because the gap is small.
 351                          */
 352                         while (j < k)
 353                                 sline[j++].flag |= mark;
 354                         i = k;
 355                         goto again;
 356                 }
 357
 358                 /* j is the first uninteresting line and there is
 359                  * no overlap beyond it within context lines.  Paint
 360                  * the trailing edge a bit.
 361                  */
 362                 i = k;
 363                 k = (j + context < cnt+1) ? j + context : cnt+1;
 364                 while (j < k)
 365                         sline[j++].flag |= mark;
 366         }
 367         return 1;
 368 }
 369
 370 static int make_hunks(struct sline *sline, unsigned long cnt,
 371                        int num_parent, int dense)
 372 {
 373         unsigned long all_mask = (1UL<<num_parent) - 1;
 374         unsigned long mark = (1UL<<num_parent);
 375         unsigned long i;
 376         int has_interesting = 0;
 377
 378         for (i = 0; i <= cnt; i++) {
 379                 if (interesting(&sline[i], all_mask))
 380                         sline[i].flag |= mark;
 381                 else
 382                         sline[i].flag &= ~mark;
 383         }
 384         if (!dense)
 385                 return give_context(sline, cnt, num_parent);
 386
 387         /* Look at each hunk, and if we have changes from only one
 388          * parent, or the changes are the same from all but one
 389          * parent, mark that uninteresting.
 390          */
 391         i = 0;
 392         while (i <= cnt) {
 393                 unsigned long j, hunk_begin, hunk_end;
 394                 unsigned long same_diff;
 395                 while (i <= cnt && !(sline[i].flag & mark))
 396                         i++;
 397                 if (cnt < i)
 398                         break; /* No more interesting hunks */
 399                 hunk_begin = i;
 400                 for (j = i + 1; j <= cnt; j++) {
 401                         if (!(sline[j].flag & mark)) {
 402                                 /* Look beyond the end to see if there
 403                                  * is an interesting line after this
 404                                  * hunk within context span.
 405                                  */
 406                                 unsigned long la; /* lookahead */
 407                                 int contin = 0;
 408                                 la = adjust_hunk_tail(sline, all_mask,
 409                                                      hunk_begin, j);
 410                                 la = (la + context < cnt + 1) ?
 411                                         (la + context) : cnt + 1;
 412                                 while (j <= --la) {
 413                                         if (sline[la].flag & mark) {
 414                                                 contin = 1;
 415                                                 break;
 416                                         }
 417                                 }
 418                                 if (!contin)
 419                                         break;
 420                                 j = la;
 421                         }
 422                 }
 423                 hunk_end = j;
 424
 425                 /* [i..hunk_end) are interesting.  Now is it really
 426                  * interesting?  We check if there are only two versions
 427                  * and the result matches one of them.  That is, we look
 428                  * at:
 429                  *   (+) line, which records lines added to which parents;
 430                  *       this line appears in the result.
 431                  *   (-) line, which records from what parents the line
 432                  *       was removed; this line does not appear in the result.
 433                  * then check the set of parents the result has difference
 434                  * from, from all lines.  If there are lines that has
 435                  * different set of parents that the result has differences
 436                  * from, that means we have more than two versions.
 437                  *
 438                  * Even when we have only two versions, if the result does
 439                  * not match any of the parents, the it should be considered
 440                  * interesting.  In such a case, we would have all '+' line.
 441                  * After passing the above "two versions" test, that would
 442                  * appear as "the same set of parents" to be "all parents".
 443                  */
 444                 same_diff = 0;
 445                 has_interesting = 0;
 446                 for (j = i; j < hunk_end && !has_interesting; j++) {
 447                         unsigned long this_diff = sline[j].flag & all_mask;
 448                         struct lline *ll = sline[j].lost_head;
 449                         if (this_diff) {
 450                                 /* This has some changes.  Is it the
 451                                  * same as others?
 452                                  */
 453                                 if (!same_diff)
 454                                         same_diff = this_diff;
 455                                 else if (same_diff != this_diff) {
 456                                         has_interesting = 1;
 457                                         break;
 458                                 }
 459                         }
 460                         while (ll && !has_interesting) {
 461                                 /* Lost this line from these parents;
 462                                  * who are they?  Are they the same?
 463                                  */
 464                                 this_diff = ll->parent_map;
 465                                 if (!same_diff)
 466                                         same_diff = this_diff;
 467                                 else if (same_diff != this_diff) {
 468                                         has_interesting = 1;
 469                                 }
 470                                 ll = ll->next;
 471                         }
 472                 }
 473
 474                 if (!has_interesting && same_diff != all_mask) {
 475                         /* This hunk is not that interesting after all */
 476                         for (j = hunk_begin; j < hunk_end; j++)
 477                                 sline[j].flag &= ~mark;
 478                 }
 479                 i = hunk_end;
 480         }
 481
 482         has_interesting = give_context(sline, cnt, num_parent);
 483         return has_interesting;
 484 }
 485
 486 static void show_parent_lno(struct sline *sline, unsigned long l0, unsigned long l1, int n)
 487 {
 488         l0 = sline[l0].p_lno[n];
 489         l1 = sline[l1].p_lno[n];
 490         printf(" -%lu,%lu", l0, l1-l0);
 491 }
 492
 493 static void dump_sline(struct sline *sline, unsigned long cnt, int num_parent,
 494                        int use_color)
 495 {
 496         unsigned long mark = (1UL<<num_parent);
 497         int i;
 498         unsigned long lno = 0;
 499         const char *c_frag = diff_get_color(use_color, DIFF_FRAGINFO);
 500         const char *c_new = diff_get_color(use_color, DIFF_FILE_NEW);
 501         const char *c_old = diff_get_color(use_color, DIFF_FILE_OLD);
 502         const char *c_plain = diff_get_color(use_color, DIFF_PLAIN);
 503         const char *c_reset = diff_get_color(use_color, DIFF_RESET);
 504
 505         if (!cnt)
 506                 return; /* result deleted */
 507
 508         while (1) {
 509                 struct sline *sl = &sline[lno];
 510                 unsigned long hunk_end;
 511                 unsigned long rlines;
 512                 while (lno <= cnt && !(sline[lno].flag & mark))
 513                         lno++;
 514                 if (cnt < lno)
 515                         break;
 516                 else {
 517                         for (hunk_end = lno + 1; hunk_end <= cnt; hunk_end++)
 518                                 if (!(sline[hunk_end].flag & mark))
 519                                         break;
 520                 }
 521                 rlines = hunk_end - lno;
 522                 if (cnt < hunk_end)
 523                         rlines--; /* pointing at the last delete hunk */
 524                 fputs(c_frag, stdout);
 525                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 526                 for (i = 0; i < num_parent; i++)
 527                         show_parent_lno(sline, lno, hunk_end, i);
 528                 printf(" +%lu,%lu ", lno+1, rlines);
 529                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 530                 printf("%s\n", c_reset);
 531                 while (lno < hunk_end) {
 532                         struct lline *ll;
 533                         int j;
 534                         unsigned long p_mask;
 535                         sl = &sline[lno++];
 536                         ll = sl->lost_head;
 537                         while (ll) {
 538                                 fputs(c_old, stdout);
 539                                 for (j = 0; j < num_parent; j++) {
 540                                         if (ll->parent_map & (1UL<<j))
 541                                                 putchar('-');
 542                                         else
 543                                                 putchar(' ');
 544                                 }
 545                                 printf("%s%s\n", ll->line, c_reset);
 546                                 ll = ll->next;
 547                         }
 548                         if (cnt < lno)
 549                                 break;
 550                         p_mask = 1;
 551                         if (!(sl->flag & (mark-1)))
 552                                 fputs(c_plain, stdout);
 553                         else
 554                                 fputs(c_new, stdout);
 555                         for (j = 0; j < num_parent; j++) {
 556                                 if (p_mask & sl->flag)
 557                                         putchar('+');
 558                                 else
 559                                         putchar(' ');
 560                                 p_mask <<= 1;
 561                         }
 562                         printf("%.*s%s\n", sl->len, sl->bol, c_reset);
 563                 }
 564         }
 565 }
 566
 567 static void reuse_combine_diff(struct sline *sline, unsigned long cnt,
 568                                int i, int j)
 569 {
 570         /* We have already examined parent j and we know parent i
 571          * and parent j are the same, so reuse the combined result
 572          * of parent j for parent i.
 573          */
 574         unsigned long lno, imask, jmask;
 575         imask = (1UL<<i);
 576         jmask = (1UL<<j);
 577
 578         for (lno = 0; lno <= cnt; lno++) {
 579                 struct lline *ll = sline->lost_head;
 580                 sline->p_lno[i] = sline->p_lno[j];
 581                 while (ll) {
 582                         if (ll->parent_map & jmask)
 583                                 ll->parent_map |= imask;
 584                         ll = ll->next;
 585                 }
 586                 if (sline->flag & jmask)
 587                         sline->flag |= imask;
 588                 sline++;
 589         }
 590         /* the overall size of the file (sline[cnt]) */
 591         sline->p_lno[i] = sline->p_lno[j];
 592 }
 593
 594 static void dump_quoted_path(const char *prefix, const char *path,
 595                              const char *c_meta, const char *c_reset)
 596 {
 597         printf("%s%s", c_meta, prefix);
 598         if (quote_c_style(path, NULL, NULL, 0))
 599                 quote_c_style(path, NULL, stdout, 0);
 600         else
 601                 printf("%s", path);
 602         printf("%s\n", c_reset);
 603 }
 604
 605 static void show_patch_diff(struct combine_diff_path *elem, int num_parent,
 606                             int dense, struct rev_info *rev)
 607 {
 608         struct diff_options *opt = &rev->diffopt;
 609         unsigned long result_size, cnt, lno;
 610         char *result, *cp;
 611         struct sline *sline; /* survived lines */
 612         int mode_differs = 0;
 613         int i, show_hunks;
 614         int working_tree_file = !memcmp(elem->sha1, null_sha1, 20);
 615         int abbrev = opt->full_index ? 40 : DEFAULT_ABBREV;
 616         mmfile_t result_file;
 617
 618         context = opt->context;
 619         /* Read the result of merge first */
 620         if (!working_tree_file)
 621                 result = grab_blob(elem->sha1, &result_size);
 622         else {
 623                 /* Used by diff-tree to read from the working tree */
 624                 struct stat st;
 625                 int fd;
 626                 if (0 <= (fd = open(elem->path, O_RDONLY)) &&
 627                     !fstat(fd, &st)) {
 628                         int len = st.st_size;
 629                         int sz = 0;
 630
 631                         elem->mode = canon_mode(st.st_mode);
 632                         result_size = len;
 633                         result = xmalloc(len + 1);
 634                         while (sz < len) {
 635                                 int done = xread(fd, result+sz, len-sz);
 636                                 if (done == 0)
 637                                         break;
 638                                 if (done < 0)
 639                                         die("read error '%s'", elem->path);
 640                                 sz += done;
 641                         }
 642                         result[len] = 0;
 643                 }
 644                 else {
 645                         /* deleted file */
 646                         result_size = 0;
 647                         elem->mode = 0;
 648                         result = xcalloc(1, 1);
 649                 }
 650                 if (0 <= fd)
 651                         close(fd);
 652         }
 653
 654         for (cnt = 0, cp = result; cp < result + result_size; cp++) {
 655                 if (*cp == '\n')
 656                         cnt++;
 657         }
 658         if (result_size && result[result_size-1] != '\n')
 659                 cnt++; /* incomplete line */
 660
 661         sline = xcalloc(cnt+2, sizeof(*sline));
 662         sline[0].bol = result;
 663         for (lno = 0; lno <= cnt + 1; lno++) {
 664                 sline[lno].lost_tail = &sline[lno].lost_head;
 665                 sline[lno].flag = 0;
 666         }
 667         for (lno = 0, cp = result; cp < result + result_size; cp++) {
 668                 if (*cp == '\n') {
 669                         sline[lno].len = cp - sline[lno].bol;
 670                         lno++;
 671                         if (lno < cnt)
 672                                 sline[lno].bol = cp + 1;
 673                 }
 674         }
 675         if (result_size && result[result_size-1] != '\n')
 676                 sline[cnt-1].len = result_size - (sline[cnt-1].bol - result);
 677
 678         result_file.ptr = result;
 679         result_file.size = result_size;
 680
 681         /* Even p_lno[cnt+1] is valid -- that is for the end line number
 682          * for deletion hunk at the end.
 683          */
 684         sline[0].p_lno = xcalloc((cnt+2) * num_parent, sizeof(unsigned long));
 685         for (lno = 0; lno <= cnt; lno++)
 686                 sline[lno+1].p_lno = sline[lno].p_lno + num_parent;
 687
 688         for (i = 0; i < num_parent; i++) {
 689                 int j;
 690                 for (j = 0; j < i; j++) {
 691                         if (!memcmp(elem->parent[i].sha1,
 692                                     elem->parent[j].sha1, 20)) {
 693                                 reuse_combine_diff(sline, cnt, i, j);
 694                                 break;
 695                         }
 696                 }
 697                 if (i <= j)
 698                         combine_diff(elem->parent[i].sha1, &result_file, sline,
 699                                      cnt, i, num_parent);
 700                 if (elem->parent[i].mode != elem->mode)
 701                         mode_differs = 1;
 702         }
 703
 704         show_hunks = make_hunks(sline, cnt, num_parent, dense);
 705
 706         if (show_hunks || mode_differs || working_tree_file) {
 707                 const char *abb;
 708                 int use_color = opt->color_diff;
 709                 const char *c_meta = diff_get_color(use_color, DIFF_METAINFO);
 710                 const char *c_reset = diff_get_color(use_color, DIFF_RESET);
 711
 712                 if (rev->loginfo)
 713                         show_log(rev, opt->msg_sep);
 714                 dump_quoted_path(dense ? "diff --cc " : "diff --combined ",
 715                                  elem->path, c_meta, c_reset);
 716                 printf("%sindex ", c_meta);
 717                 for (i = 0; i < num_parent; i++) {
 718                         abb = find_unique_abbrev(elem->parent[i].sha1,
 719                                                  abbrev);
 720                         printf("%s%s", i ? "," : "", abb);
 721                 }
 722                 abb = find_unique_abbrev(elem->sha1, abbrev);
 723                 printf("..%s%s\n", abb, c_reset);
 724
 725                 if (mode_differs) {
 726                         int added = !!elem->mode;
 727                         for (i = 0; added && i < num_parent; i++)
 728                                 if (elem->parent[i].status !=
 729                                     DIFF_STATUS_ADDED)
 730                                         added = 0;
 731                         if (added)
 732                                 printf("%snew file mode %06o",
 733                                        c_meta, elem->mode);
 734                         else {
 735                                 if (!elem->mode)
 736                                         printf("%sdeleted file ", c_meta);
 737                                 printf("mode ");
 738                                 for (i = 0; i < num_parent; i++) {
 739                                         printf("%s%06o", i ? "," : "",
 740                                                elem->parent[i].mode);
 741                                 }
 742                                 if (elem->mode)
 743                                         printf("..%06o", elem->mode);
 744                         }
 745                         printf("%s\n", c_reset);
 746                 }
 747                 dump_quoted_path("--- a/", elem->path, c_meta, c_reset);
 748                 dump_quoted_path("+++ b/", elem->path, c_meta, c_reset);
 749                 dump_sline(sline, cnt, num_parent, opt->color_diff);
 750         }
 751         free(result);
 752
 753         for (lno = 0; lno < cnt; lno++) {
 754                 if (sline[lno].lost_head) {
 755                         struct lline *ll = sline[lno].lost_head;
 756                         while (ll) {
 757                                 struct lline *tmp = ll;
 758                                 ll = ll->next;
 759                                 free(tmp);
 760                         }
 761                 }
 762         }
 763         free(sline[0].p_lno);
 764         free(sline);
 765 }
 766
 767 #define COLONS "::::::::::::::::::::::::::::::::"
 768
 769 static void show_raw_diff(struct combine_diff_path *p, int num_parent, struct rev_info *rev)
 770 {
 771         struct diff_options *opt = &rev->diffopt;
 772         int i, offset;
 773         const char *prefix;
 774         int line_termination, inter_name_termination;
 775
 776         line_termination = opt->line_termination;
 777         inter_name_termination = '\t';
 778         if (!line_termination)
 779                 inter_name_termination = 0;
 780
 781         if (rev->loginfo)
 782                 show_log(rev, opt->msg_sep);
 783
 784         if (opt->output_format & DIFF_FORMAT_RAW) {
 785                 offset = strlen(COLONS) - num_parent;
 786                 if (offset < 0)
 787                         offset = 0;
 788                 prefix = COLONS + offset;
 789
 790                 /* Show the modes */
 791                 for (i = 0; i < num_parent; i++) {
 792                         printf("%s%06o", prefix, p->parent[i].mode);
 793                         prefix = " ";
 794                 }
 795                 printf("%s%06o", prefix, p->mode);
 796
 797                 /* Show sha1's */
 798                 for (i = 0; i < num_parent; i++)
 799                         printf(" %s", diff_unique_abbrev(p->parent[i].sha1,
 800                                                          opt->abbrev));
 801                 printf(" %s ", diff_unique_abbrev(p->sha1, opt->abbrev));
 802         }
 803
 804         if (opt->output_format & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS)) {
 805                 for (i = 0; i < num_parent; i++)
 806                         putchar(p->parent[i].status);
 807                 putchar(inter_name_termination);
 808         }
 809
 810         if (line_termination) {
 811                 if (quote_c_style(p->path, NULL, NULL, 0))
 812                         quote_c_style(p->path, NULL, stdout, 0);
 813                 else
 814                         printf("%s", p->path);
 815                 putchar(line_termination);
 816         }
 817         else {
 818                 printf("%s%c", p->path, line_termination);
 819         }
 820 }
 821
 822 void show_combined_diff(struct combine_diff_path *p,
 823                        int num_parent,
 824                        int dense,
 825                        struct rev_info *rev)
 826 {
 827         struct diff_options *opt = &rev->diffopt;
 828         if (!p->len)
 829                 return;
 830         if (opt->output_format & (DIFF_FORMAT_RAW |
 831                                   DIFF_FORMAT_NAME |
 832                                   DIFF_FORMAT_NAME_STATUS))
 833                 show_raw_diff(p, num_parent, rev);
 834         else if (opt->output_format & DIFF_FORMAT_PATCH)
 835                 show_patch_diff(p, num_parent, dense, rev);
 836 }
 837
 838 void diff_tree_combined(const unsigned char *sha1,
 839                         const unsigned char parent[][20],
 840                         int num_parent,
 841                         int dense,
 842                         struct rev_info *rev)
 843 {
 844         struct diff_options *opt = &rev->diffopt;
 845         struct diff_options diffopts;
 846         struct combine_diff_path *p, *paths = NULL;
 847         int i, num_paths, needsep, show_log_first;
 848
 849         diffopts = *opt;
 850         diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
 851         diffopts.recursive = 1;
 852
 853         show_log_first = !!rev->loginfo;
 854         needsep = 0;
 855         /* find set of paths that everybody touches */
 856         for (i = 0; i < num_parent; i++) {
 857                 /* show stat against the first parent even
 858                  * when doing combined diff.
 859                  */
 860                 if (i == 0 && opt->output_format & DIFF_FORMAT_DIFFSTAT)
 861                         diffopts.output_format = DIFF_FORMAT_DIFFSTAT;
 862                 else
 863                         diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
 864                 diff_tree_sha1(parent[i], sha1, "", &diffopts);
 865                 diffcore_std(&diffopts);
 866                 paths = intersect_paths(paths, i, num_parent);
 867
 868                 if (show_log_first && i == 0) {
 869                         show_log(rev, opt->msg_sep);
 870                         if (rev->verbose_header && opt->output_format)
 871                                 putchar(opt->line_termination);
 872                 }
 873                 diff_flush(&diffopts);
 874         }
 875
 876         /* find out surviving paths */
 877         for (num_paths = 0, p = paths; p; p = p->next) {
 878                 if (p->len)
 879                         num_paths++;
 880         }
 881         if (num_paths) {
 882                 if (opt->output_format & (DIFF_FORMAT_RAW |
 883                                           DIFF_FORMAT_NAME |
 884                                           DIFF_FORMAT_NAME_STATUS)) {
 885                         for (p = paths; p; p = p->next) {
 886                                 if (p->len)
 887                                         show_raw_diff(p, num_parent, rev);
 888                         }
 889                         needsep = 1;
 890                 }
 891                 else if (opt->output_format & DIFF_FORMAT_DIFFSTAT)
 892                         needsep = 1;
 893                 if (opt->output_format & DIFF_FORMAT_PATCH) {
 894                         if (needsep)
 895                                 putchar(opt->line_termination);
 896                         for (p = paths; p; p = p->next) {
 897                                 if (p->len)
 898                                         show_patch_diff(p, num_parent, dense,
 899                                                         rev);
 900                         }
 901                 }
 902         }
 903
 904         /* Clean things up */
 905         while (paths) {
 906                 struct combine_diff_path *tmp = paths;
 907                 paths = paths->next;
 908                 free(tmp);
 909         }
 910 }
 911
 912 void diff_tree_combined_merge(const unsigned char *sha1,
 913                              int dense, struct rev_info *rev)
 914 {
 915         int num_parent;
 916         const unsigned char (*parent)[20];
 917         struct commit *commit = lookup_commit(sha1);
 918         struct commit_list *parents;
 919
 920         /* count parents */
 921         for (parents = commit->parents, num_parent = 0;
 922              parents;
 923              parents = parents->next, num_parent++)
 924                 ; /* nothing */
 925
 926         parent = xmalloc(num_parent * sizeof(*parent));
 927         for (parents = commit->parents, num_parent = 0;
 928              parents;
 929              parents = parents->next, num_parent++)
 930                 memcpy(parent + num_parent, parents->item->object.sha1, 20);
 931         diff_tree_combined(sha1, parent, num_parent, dense, rev);
 932 }