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/xdiff.h"
   8
   9 static int uninteresting(struct diff_filepair *p)
  10 {
  11         if (diff_unmodified_pair(p))
  12                 return 1;
  13         return 0;
  14 }
  15
  16 static struct combine_diff_path *intersect_paths(struct combine_diff_path *curr, int n, int num_parent)
  17 {
  18         struct diff_queue_struct *q = &diff_queued_diff;
  19         struct combine_diff_path *p;
  20         int i;
  21
  22         if (!n) {
  23                 struct combine_diff_path *list = NULL, **tail = &list;
  24                 for (i = 0; i < q->nr; i++) {
  25                         int len;
  26                         const char *path;
  27                         if (uninteresting(q->queue[i]))
  28                                 continue;
  29                         path = q->queue[i]->two->path;
  30                         len = strlen(path);
  31                         p = xmalloc(combine_diff_path_size(num_parent, len));
  32                         p->path = (char*) &(p->parent[num_parent]);
  33                         memcpy(p->path, path, len);
  34                         p->path[len] = 0;
  35                         p->len = len;
  36                         p->next = NULL;
  37                         memset(p->parent, 0,
  38                                sizeof(p->parent[0]) * num_parent);
  39
  40                         memcpy(p->sha1, q->queue[i]->two->sha1, 20);
  41                         p->mode = q->queue[i]->two->mode;
  42                         memcpy(p->parent[n].sha1, q->queue[i]->one->sha1, 20);
  43                         p->parent[n].mode = q->queue[i]->one->mode;
  44                         p->parent[n].status = q->queue[i]->status;
  45                         *tail = p;
  46                         tail = &p->next;
  47                 }
  48                 return list;
  49         }
  50
  51         for (p = curr; p; p = p->next) {
  52                 int found = 0;
  53                 if (!p->len)
  54                         continue;
  55                 for (i = 0; i < q->nr; i++) {
  56                         const char *path;
  57                         int len;
  58
  59                         if (uninteresting(q->queue[i]))
  60                                 continue;
  61                         path = q->queue[i]->two->path;
  62                         len = strlen(path);
  63                         if (len == p->len && !memcmp(path, p->path, len)) {
  64                                 found = 1;
  65                                 memcpy(p->parent[n].sha1,
  66                                        q->queue[i]->one->sha1, 20);
  67                                 p->parent[n].mode = q->queue[i]->one->mode;
  68                                 p->parent[n].status = q->queue[i]->status;
  69                                 break;
  70                         }
  71                 }
  72                 if (!found)
  73                         p->len = 0;
  74         }
  75         return curr;
  76 }
  77
  78 /* Lines lost from parent */
  79 struct lline {
  80         struct lline *next;
  81         int len;
  82         unsigned long parent_map;
  83         char line[FLEX_ARRAY];
  84 };
  85
  86 /* Lines surviving in the merge result */
  87 struct sline {
  88         struct lline *lost_head, **lost_tail;
  89         char *bol;
  90         int len;
  91         /* bit 0 up to (N-1) are on if the parent has this line (i.e.
  92          * we did not change it).
  93          * bit N is used for "interesting" lines, including context.
  94          */
  95         unsigned long flag;
  96         unsigned long *p_lno;
  97 };
  98
  99 static char *grab_blob(const unsigned char *sha1, unsigned long *size)
 100 {
 101         char *blob;
 102         char type[20];
 103         if (!memcmp(sha1, null_sha1, 20)) {
 104                 /* deleted blob */
 105                 *size = 0;
 106                 return xcalloc(1, 1);
 107         }
 108         blob = read_sha1_file(sha1, type, size);
 109         if (strcmp(type, blob_type))
 110                 die("object '%s' is not a blob!", sha1_to_hex(sha1));
 111         return blob;
 112 }
 113
 114 static int parse_num(char **cp_p, unsigned int *num_p)
 115 {
 116         char *cp = *cp_p;
 117         unsigned int num = 0;
 118         int read_some;
 119
 120         while ('0' <= *cp && *cp <= '9')
 121                 num = num * 10 + *cp++ - '0';
 122         if (!(read_some = cp - *cp_p))
 123                 return -1;
 124         *cp_p = cp;
 125         *num_p = num;
 126         return 0;
 127 }
 128
 129 static int parse_hunk_header(char *line, int len,
 130                              unsigned int *ob, unsigned int *on,
 131                              unsigned int *nb, unsigned int *nn)
 132 {
 133         char *cp;
 134         cp = line + 4;
 135         if (parse_num(&cp, ob)) {
 136         bad_line:
 137                 return error("malformed diff output: %s", line);
 138         }
 139         if (*cp == ',') {
 140                 cp++;
 141                 if (parse_num(&cp, on))
 142                         goto bad_line;
 143         }
 144         else
 145                 *on = 1;
 146         if (*cp++ != ' ' || *cp++ != '+')
 147                 goto bad_line;
 148         if (parse_num(&cp, nb))
 149                 goto bad_line;
 150         if (*cp == ',') {
 151                 cp++;
 152                 if (parse_num(&cp, nn))
 153                         goto bad_line;
 154         }
 155         else
 156                 *nn = 1;
 157         return -!!memcmp(cp, " @@", 3);
 158 }
 159
 160 static void append_lost(struct sline *sline, int n, const char *line, int len)
 161 {
 162         struct lline *lline;
 163         unsigned long this_mask = (1UL<<n);
 164         if (line[len-1] == '\n')
 165                 len--;
 166
 167         /* Check to see if we can squash things */
 168         if (sline->lost_head) {
 169                 struct lline *last_one = NULL;
 170                 /* We cannot squash it with earlier one */
 171                 for (lline = sline->lost_head;
 172                      lline;
 173                      lline = lline->next)
 174                         if (lline->parent_map & this_mask)
 175                                 last_one = lline;
 176                 lline = last_one ? last_one->next : sline->lost_head;
 177                 while (lline) {
 178                         if (lline->len == len &&
 179                             !memcmp(lline->line, line, len)) {
 180                                 lline->parent_map |= this_mask;
 181                                 return;
 182                         }
 183                         lline = lline->next;
 184                 }
 185         }
 186
 187         lline = xmalloc(sizeof(*lline) + len + 1);
 188         lline->len = len;
 189         lline->next = NULL;
 190         lline->parent_map = this_mask;
 191         memcpy(lline->line, line, len);
 192         lline->line[len] = 0;
 193         *sline->lost_tail = lline;
 194         sline->lost_tail = &lline->next;
 195 }
 196
 197 struct combine_diff_state {
 198         char *remainder;
 199         unsigned long remainder_size;
 200         unsigned int lno, ob, on, nb, nn;
 201         unsigned long nmask;
 202         int num_parent;
 203         int n;
 204         struct sline *sline;
 205         struct sline *lost_bucket;
 206 };
 207
 208 static void consume_line(struct combine_diff_state *state,
 209                          char *line,
 210                          unsigned long len)
 211 {
 212         if (5 < len && !memcmp("@@ -", line, 4)) {
 213                 if (parse_hunk_header(line, len,
 214                                       &state->ob, &state->on,
 215                                       &state->nb, &state->nn))
 216                         return;
 217                 state->lno = state->nb;
 218                 if (!state->nb)
 219                         /* @@ -1,2 +0,0 @@ to remove the
 220                          * first two lines...
 221                          */
 222                         state->nb = 1;
 223                 if (state->nn == 0)
 224                         /* @@ -X,Y +N,0 @@ removed Y lines
 225                          * that would have come *after* line N
 226                          * in the result.  Our lost buckets hang
 227                          * to the line after the removed lines,
 228                          */
 229                         state->lost_bucket = &state->sline[state->nb];
 230                 else
 231                         state->lost_bucket = &state->sline[state->nb-1];
 232                 if (!state->sline[state->nb-1].p_lno)
 233                         state->sline[state->nb-1].p_lno =
 234                                 xcalloc(state->num_parent,
 235                                         sizeof(unsigned long));
 236                 state->sline[state->nb-1].p_lno[state->n] = state->ob;
 237                 return;
 238         }
 239         if (!state->lost_bucket)
 240                 return; /* not in any hunk yet */
 241         switch (line[0]) {
 242         case '-':
 243                 append_lost(state->lost_bucket, state->n, line+1, len-1);
 244                 break;
 245         case '+':
 246                 state->sline[state->lno-1].flag |= state->nmask;
 247                 state->lno++;
 248                 break;
 249         }
 250 }
 251
 252 static int combine_diff_outf(void *priv_, mmbuffer_t *mb, int nbuf)
 253 {
 254         struct combine_diff_state *priv = priv_;
 255         int i;
 256         for (i = 0; i < nbuf; i++) {
 257                 if (mb[i].ptr[mb[i].size-1] != '\n') {
 258                         /* Incomplete line */
 259                         priv->remainder = realloc(priv->remainder,
 260                                                   priv->remainder_size +
 261                                                   mb[i].size);
 262                         memcpy(priv->remainder + priv->remainder_size,
 263                                mb[i].ptr, mb[i].size);
 264                         priv->remainder_size += mb[i].size;
 265                         continue;
 266                 }
 267
 268                 /* we have a complete line */
 269                 if (!priv->remainder) {
 270                         consume_line(priv, mb[i].ptr, mb[i].size);
 271                         continue;
 272                 }
 273                 priv->remainder = realloc(priv->remainder,
 274                                           priv->remainder_size +
 275                                           mb[i].size);
 276                 memcpy(priv->remainder + priv->remainder_size,
 277                        mb[i].ptr, mb[i].size);
 278                 consume_line(priv, priv->remainder,
 279                              priv->remainder_size + mb[i].size);
 280                 free(priv->remainder);
 281                 priv->remainder = NULL;
 282                 priv->remainder_size = 0;
 283         }
 284         return 0;
 285 }
 286
 287 static void combine_diff(const unsigned char *parent, mmfile_t *result_file,
 288                          struct sline *sline, int cnt, int n, int num_parent)
 289 {
 290         unsigned int p_lno, lno;
 291         unsigned long nmask = (1UL << n);
 292         xpparam_t xpp;
 293         xdemitconf_t xecfg;
 294         mmfile_t parent_file;
 295         xdemitcb_t ecb;
 296         struct combine_diff_state state;
 297         unsigned long sz;
 298
 299         if (!cnt)
 300                 return; /* result deleted */
 301
 302         parent_file.ptr = grab_blob(parent, &sz);
 303         parent_file.size = sz;
 304         xpp.flags = XDF_NEED_MINIMAL;
 305         xecfg.ctxlen = 0;
 306         xecfg.flags = 0;
 307         ecb.outf = combine_diff_outf;
 308         ecb.priv = &state;
 309         memset(&state, 0, sizeof(state));
 310         state.nmask = nmask;
 311         state.sline = sline;
 312         state.lno = 1;
 313         state.num_parent = num_parent;
 314         state.n = n;
 315
 316         xdl_diff(&parent_file, result_file, &xpp, &xecfg, &ecb);
 317         if (state.remainder && state.remainder_size)
 318                 consume_line(&state, state.remainder, state.remainder_size);
 319         free(state.remainder);
 320         free(parent_file.ptr);
 321
 322         /* Assign line numbers for this parent.
 323          *
 324          * sline[lno].p_lno[n] records the first line number
 325          * (counting from 1) for parent N if the final hunk display
 326          * started by showing sline[lno] (possibly showing the lost
 327          * lines attached to it first).
 328          */
 329         for (lno = 0,  p_lno = 1; lno < cnt; lno++) {
 330                 struct lline *ll;
 331                 sline[lno].p_lno[n] = p_lno;
 332
 333                 /* How many lines would this sline advance the p_lno? */
 334                 ll = sline[lno].lost_head;
 335                 while (ll) {
 336                         if (ll->parent_map & nmask)
 337                                 p_lno++; /* '-' means parent had it */
 338                         ll = ll->next;
 339                 }
 340                 if (!(sline[lno].flag & nmask))
 341                         p_lno++; /* no '+' means parent had it */
 342         }
 343         sline[lno].p_lno[n] = p_lno; /* trailer */
 344 }
 345
 346 static unsigned long context = 3;
 347 static char combine_marker = '@';
 348
 349 static int interesting(struct sline *sline, unsigned long all_mask)
 350 {
 351         /* If some parents lost lines here, or if we have added to
 352          * some parent, it is interesting.
 353          */
 354         return ((sline->flag & all_mask) || sline->lost_head);
 355 }
 356
 357 static unsigned long adjust_hunk_tail(struct sline *sline,
 358                                       unsigned long all_mask,
 359                                       unsigned long hunk_begin,
 360                                       unsigned long i)
 361 {
 362         /* i points at the first uninteresting line.  If the last line
 363          * of the hunk was interesting only because it has some
 364          * deletion, then it is not all that interesting for the
 365          * purpose of giving trailing context lines.  This is because
 366          * we output '-' line and then unmodified sline[i-1] itself in
 367          * that case which gives us one extra context line.
 368          */
 369         if ((hunk_begin + 1 <= i) && !(sline[i-1].flag & all_mask))
 370                 i--;
 371         return i;
 372 }
 373
 374 static unsigned long find_next(struct sline *sline,
 375                                unsigned long mark,
 376                                unsigned long i,
 377                                unsigned long cnt,
 378                                int uninteresting)
 379 {
 380         /* We have examined up to i-1 and are about to look at i.
 381          * Find next interesting or uninteresting line.  Here,
 382          * "interesting" does not mean interesting(), but marked by
 383          * the give_context() function below (i.e. it includes context
 384          * lines that are not interesting to interesting() function
 385          * that are surrounded by interesting() ones.
 386          */
 387         while (i < cnt)
 388                 if (uninteresting
 389                     ? !(sline[i].flag & mark)
 390                     : (sline[i].flag & mark))
 391                         return i;
 392                 else
 393                         i++;
 394         return cnt;
 395 }
 396
 397 static int give_context(struct sline *sline, unsigned long cnt, int num_parent)
 398 {
 399         unsigned long all_mask = (1UL<<num_parent) - 1;
 400         unsigned long mark = (1UL<<num_parent);
 401         unsigned long i;
 402
 403         /* Two groups of interesting lines may have a short gap of
 404          * unintersting lines.  Connect such groups to give them a
 405          * bit of context.
 406          *
 407          * We first start from what the interesting() function says,
 408          * and mark them with "mark", and paint context lines with the
 409          * mark.  So interesting() would still say false for such context
 410          * lines but they are treated as "interesting" in the end.
 411          */
 412         i = find_next(sline, mark, 0, cnt, 0);
 413         if (cnt <= i)
 414                 return 0;
 415
 416         while (i < cnt) {
 417                 unsigned long j = (context < i) ? (i - context) : 0;
 418                 unsigned long k;
 419
 420                 /* Paint a few lines before the first interesting line. */
 421                 while (j < i)
 422                         sline[j++].flag |= mark;
 423
 424         again:
 425                 /* we know up to i is to be included.  where does the
 426                  * next uninteresting one start?
 427                  */
 428                 j = find_next(sline, mark, i, cnt, 1);
 429                 if (cnt <= j)
 430                         break; /* the rest are all interesting */
 431
 432                 /* lookahead context lines */
 433                 k = find_next(sline, mark, j, cnt, 0);
 434                 j = adjust_hunk_tail(sline, all_mask, i, j);
 435
 436                 if (k < j + context) {
 437                         /* k is interesting and [j,k) are not, but
 438                          * paint them interesting because the gap is small.
 439                          */
 440                         while (j < k)
 441                                 sline[j++].flag |= mark;
 442                         i = k;
 443                         goto again;
 444                 }
 445
 446                 /* j is the first uninteresting line and there is
 447                  * no overlap beyond it within context lines.  Paint
 448                  * the trailing edge a bit.
 449                  */
 450                 i = k;
 451                 k = (j + context < cnt) ? j + context : cnt;
 452                 while (j < k)
 453                         sline[j++].flag |= mark;
 454         }
 455         return 1;
 456 }
 457
 458 static int make_hunks(struct sline *sline, unsigned long cnt,
 459                        int num_parent, int dense)
 460 {
 461         unsigned long all_mask = (1UL<<num_parent) - 1;
 462         unsigned long mark = (1UL<<num_parent);
 463         unsigned long i;
 464         int has_interesting = 0;
 465
 466         for (i = 0; i < cnt; i++) {
 467                 if (interesting(&sline[i], all_mask))
 468                         sline[i].flag |= mark;
 469                 else
 470                         sline[i].flag &= ~mark;
 471         }
 472         if (!dense)
 473                 return give_context(sline, cnt, num_parent);
 474
 475         /* Look at each hunk, and if we have changes from only one
 476          * parent, or the changes are the same from all but one
 477          * parent, mark that uninteresting.
 478          */
 479         i = 0;
 480         while (i < cnt) {
 481                 unsigned long j, hunk_begin, hunk_end;
 482                 unsigned long same_diff;
 483                 while (i < cnt && !(sline[i].flag & mark))
 484                         i++;
 485                 if (cnt <= i)
 486                         break; /* No more interesting hunks */
 487                 hunk_begin = i;
 488                 for (j = i + 1; j < cnt; j++) {
 489                         if (!(sline[j].flag & mark)) {
 490                                 /* Look beyond the end to see if there
 491                                  * is an interesting line after this
 492                                  * hunk within context span.
 493                                  */
 494                                 unsigned long la; /* lookahead */
 495                                 int contin = 0;
 496                                 la = adjust_hunk_tail(sline, all_mask,
 497                                                      hunk_begin, j);
 498                                 la = (la + context < cnt) ?
 499                                         (la + context) : cnt;
 500                                 while (j <= --la) {
 501                                         if (sline[la].flag & mark) {
 502                                                 contin = 1;
 503                                                 break;
 504                                         }
 505                                 }
 506                                 if (!contin)
 507                                         break;
 508                                 j = la;
 509                         }
 510                 }
 511                 hunk_end = j;
 512
 513                 /* [i..hunk_end) are interesting.  Now is it really
 514                  * interesting?  We check if there are only two versions
 515                  * and the result matches one of them.  That is, we look
 516                  * at:
 517                  *   (+) line, which records lines added to which parents;
 518                  *       this line appears in the result.
 519                  *   (-) line, which records from what parents the line
 520                  *       was removed; this line does not appear in the result.
 521                  * then check the set of parents the result has difference
 522                  * from, from all lines.  If there are lines that has
 523                  * different set of parents that the result has differences
 524                  * from, that means we have more than two versions.
 525                  *
 526                  * Even when we have only two versions, if the result does
 527                  * not match any of the parents, the it should be considered
 528                  * interesting.  In such a case, we would have all '+' line.
 529                  * After passing the above "two versions" test, that would
 530                  * appear as "the same set of parents" to be "all parents".
 531                  */
 532                 same_diff = 0;
 533                 has_interesting = 0;
 534                 for (j = i; j < hunk_end && !has_interesting; j++) {
 535                         unsigned long this_diff = sline[j].flag & all_mask;
 536                         struct lline *ll = sline[j].lost_head;
 537                         if (this_diff) {
 538                                 /* This has some changes.  Is it the
 539                                  * same as others?
 540                                  */
 541                                 if (!same_diff)
 542                                         same_diff = this_diff;
 543                                 else if (same_diff != this_diff) {
 544                                         has_interesting = 1;
 545                                         break;
 546                                 }
 547                         }
 548                         while (ll && !has_interesting) {
 549                                 /* Lost this line from these parents;
 550                                  * who are they?  Are they the same?
 551                                  */
 552                                 this_diff = ll->parent_map;
 553                                 if (!same_diff)
 554                                         same_diff = this_diff;
 555                                 else if (same_diff != this_diff) {
 556                                         has_interesting = 1;
 557                                 }
 558                                 ll = ll->next;
 559                         }
 560                 }
 561
 562                 if (!has_interesting && same_diff != all_mask) {
 563                         /* This hunk is not that interesting after all */
 564                         for (j = hunk_begin; j < hunk_end; j++)
 565                                 sline[j].flag &= ~mark;
 566                 }
 567                 i = hunk_end;
 568         }
 569
 570         has_interesting = give_context(sline, cnt, num_parent);
 571         return has_interesting;
 572 }
 573
 574 static void show_parent_lno(struct sline *sline, unsigned long l0, unsigned long l1, unsigned long cnt, int n)
 575 {
 576         l0 = sline[l0].p_lno[n];
 577         l1 = sline[l1].p_lno[n];
 578         printf(" -%lu,%lu", l0, l1-l0);
 579 }
 580
 581 static void dump_sline(struct sline *sline, unsigned long cnt, int num_parent)
 582 {
 583         unsigned long mark = (1UL<<num_parent);
 584         int i;
 585         unsigned long lno = 0;
 586
 587         if (!cnt)
 588                 return; /* result deleted */
 589
 590         while (1) {
 591                 struct sline *sl = &sline[lno];
 592                 int hunk_end;
 593                 while (lno < cnt && !(sline[lno].flag & mark))
 594                         lno++;
 595                 if (cnt <= lno)
 596                         break;
 597                 for (hunk_end = lno + 1; hunk_end < cnt; hunk_end++)
 598                         if (!(sline[hunk_end].flag & mark))
 599                                 break;
 600                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 601                 for (i = 0; i < num_parent; i++)
 602                         show_parent_lno(sline, lno, hunk_end, cnt, i);
 603                 printf(" +%lu,%lu ", lno+1, hunk_end-lno);
 604                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 605                 putchar('\n');
 606                 while (lno < hunk_end) {
 607                         struct lline *ll;
 608                         int j;
 609                         unsigned long p_mask;
 610                         sl = &sline[lno++];
 611                         ll = sl->lost_head;
 612                         while (ll) {
 613                                 for (j = 0; j < num_parent; j++) {
 614                                         if (ll->parent_map & (1UL<<j))
 615                                                 putchar('-');
 616                                         else
 617                                                 putchar(' ');
 618                                 }
 619                                 puts(ll->line);
 620                                 ll = ll->next;
 621                         }
 622                         p_mask = 1;
 623                         for (j = 0; j < num_parent; j++) {
 624                                 if (p_mask & sl->flag)
 625                                         putchar('+');
 626                                 else
 627                                         putchar(' ');
 628                                 p_mask <<= 1;
 629                         }
 630                         printf("%.*s\n", sl->len, sl->bol);
 631                 }
 632         }
 633 }
 634
 635 static void reuse_combine_diff(struct sline *sline, unsigned long cnt,
 636                                int i, int j)
 637 {
 638         /* We have already examined parent j and we know parent i
 639          * and parent j are the same, so reuse the combined result
 640          * of parent j for parent i.
 641          */
 642         unsigned long lno, imask, jmask;
 643         imask = (1UL<<i);
 644         jmask = (1UL<<j);
 645
 646         for (lno = 0; lno < cnt; lno++) {
 647                 struct lline *ll = sline->lost_head;
 648                 sline->p_lno[i] = sline->p_lno[j];
 649                 while (ll) {
 650                         if (ll->parent_map & jmask)
 651                                 ll->parent_map |= imask;
 652                         ll = ll->next;
 653                 }
 654                 if (sline->flag & jmask)
 655                         sline->flag |= imask;
 656                 sline++;
 657         }
 658         /* the overall size of the file (sline[cnt]) */
 659         sline->p_lno[i] = sline->p_lno[j];
 660 }
 661
 662 static int show_patch_diff(struct combine_diff_path *elem, int num_parent,
 663                            int dense, const char *header,
 664                            struct diff_options *opt)
 665 {
 666         unsigned long result_size, cnt, lno;
 667         char *result, *cp, *ep;
 668         struct sline *sline; /* survived lines */
 669         int mode_differs = 0;
 670         int i, show_hunks, shown_header = 0;
 671         int working_tree_file = !memcmp(elem->sha1, null_sha1, 20);
 672         int abbrev = opt->full_index ? 40 : DEFAULT_ABBREV;
 673         mmfile_t result_file;
 674
 675         /* Read the result of merge first */
 676         if (!working_tree_file)
 677                 result = grab_blob(elem->sha1, &result_size);
 678         else {
 679                 /* Used by diff-tree to read from the working tree */
 680                 struct stat st;
 681                 int fd;
 682                 if (0 <= (fd = open(elem->path, O_RDONLY)) &&
 683                     !fstat(fd, &st)) {
 684                         int len = st.st_size;
 685                         int cnt = 0;
 686
 687                         elem->mode = canon_mode(st.st_mode);
 688                         result_size = len;
 689                         result = xmalloc(len + 1);
 690                         while (cnt < len) {
 691                                 int done = xread(fd, result+cnt, len-cnt);
 692                                 if (done == 0)
 693                                         break;
 694                                 if (done < 0)
 695                                         die("read error '%s'", elem->path);
 696                                 cnt += done;
 697                         }
 698                         result[len] = 0;
 699                 }
 700                 else {
 701                         /* deleted file */
 702                         result_size = 0;
 703                         elem->mode = 0;
 704                         result = xmalloc(1);
 705                         result[0] = 0;
 706                 }
 707                 if (0 <= fd)
 708                         close(fd);
 709         }
 710
 711         for (cnt = 0, cp = result; cp - result < result_size; cp++) {
 712                 if (*cp == '\n')
 713                         cnt++;
 714         }
 715         if (result_size && result[result_size-1] != '\n')
 716                 cnt++; /* incomplete line */
 717
 718         sline = xcalloc(cnt+1, sizeof(*sline));
 719         ep = result;
 720         sline[0].bol = result;
 721         for (lno = 0; lno <= cnt; lno++) {
 722                 sline[lno].lost_tail = &sline[lno].lost_head;
 723                 sline[lno].flag = 0;
 724         }
 725         for (lno = 0, cp = result; cp - result < result_size; cp++) {
 726                 if (*cp == '\n') {
 727                         sline[lno].len = cp - sline[lno].bol;
 728                         lno++;
 729                         if (lno < cnt)
 730                                 sline[lno].bol = cp + 1;
 731                 }
 732         }
 733         if (result_size && result[result_size-1] != '\n')
 734                 sline[cnt-1].len = result_size - (sline[cnt-1].bol - result);
 735
 736         result_file.ptr = result;
 737         result_file.size = result_size;
 738
 739         sline[0].p_lno = xcalloc((cnt+1) * num_parent, sizeof(unsigned long));
 740         for (lno = 0; lno < cnt; lno++)
 741                 sline[lno+1].p_lno = sline[lno].p_lno + num_parent;
 742
 743         for (i = 0; i < num_parent; i++) {
 744                 int j;
 745                 for (j = 0; j < i; j++) {
 746                         if (!memcmp(elem->parent[i].sha1,
 747                                     elem->parent[j].sha1, 20)) {
 748                                 reuse_combine_diff(sline, cnt, i, j);
 749                                 break;
 750                         }
 751                 }
 752                 if (i <= j)
 753                         combine_diff(elem->parent[i].sha1, &result_file, sline,
 754                                      cnt, i, num_parent);
 755                 if (elem->parent[i].mode != elem->mode)
 756                         mode_differs = 1;
 757         }
 758
 759         show_hunks = make_hunks(sline, cnt, num_parent, dense);
 760
 761         if (show_hunks || mode_differs || working_tree_file) {
 762                 const char *abb;
 763
 764                 if (header) {
 765                         shown_header++;
 766                         printf("%s%c", header, opt->line_termination);
 767                 }
 768                 printf("diff --%s ", dense ? "cc" : "combined");
 769                 if (quote_c_style(elem->path, NULL, NULL, 0))
 770                         quote_c_style(elem->path, NULL, stdout, 0);
 771                 else
 772                         printf("%s", elem->path);
 773                 putchar('\n');
 774                 printf("index ");
 775                 for (i = 0; i < num_parent; i++) {
 776                         abb = find_unique_abbrev(elem->parent[i].sha1,
 777                                                  abbrev);
 778                         printf("%s%s", i ? "," : "", abb);
 779                 }
 780                 abb = find_unique_abbrev(elem->sha1, abbrev);
 781                 printf("..%s\n", abb);
 782
 783                 if (mode_differs) {
 784                         int added = !!elem->mode;
 785                         for (i = 0; added && i < num_parent; i++)
 786                                 if (elem->parent[i].status !=
 787                                     DIFF_STATUS_ADDED)
 788                                         added = 0;
 789                         if (added)
 790                                 printf("new file mode %06o", elem->mode);
 791                         else {
 792                                 if (!elem->mode)
 793                                         printf("deleted file ");
 794                                 printf("mode ");
 795                                 for (i = 0; i < num_parent; i++) {
 796                                         printf("%s%06o", i ? "," : "",
 797                                                elem->parent[i].mode);
 798                                 }
 799                                 if (elem->mode)
 800                                         printf("..%06o", elem->mode);
 801                         }
 802                         putchar('\n');
 803                 }
 804                 dump_sline(sline, cnt, num_parent);
 805         }
 806         free(result);
 807
 808         for (i = 0; i < cnt; i++) {
 809                 if (sline[i].lost_head) {
 810                         struct lline *ll = sline[i].lost_head;
 811                         while (ll) {
 812                                 struct lline *tmp = ll;
 813                                 ll = ll->next;
 814                                 free(tmp);
 815                         }
 816                 }
 817         }
 818         free(sline[0].p_lno);
 819         free(sline);
 820         return shown_header;
 821 }
 822
 823 #define COLONS "::::::::::::::::::::::::::::::::"
 824
 825 static void show_raw_diff(struct combine_diff_path *p, int num_parent, const char *header, struct diff_options *opt)
 826 {
 827         int i, offset, mod_type = 'A';
 828         const char *prefix;
 829         int line_termination, inter_name_termination;
 830
 831         line_termination = opt->line_termination;
 832         inter_name_termination = '\t';
 833         if (!line_termination)
 834                 inter_name_termination = 0;
 835
 836         if (header)
 837                 printf("%s%c", header, line_termination);
 838
 839         for (i = 0; i < num_parent; i++) {
 840                 if (p->parent[i].mode)
 841                         mod_type = 'M';
 842         }
 843         if (!p->mode)
 844                 mod_type = 'D';
 845
 846         if (opt->output_format == DIFF_FORMAT_RAW) {
 847                 offset = strlen(COLONS) - num_parent;
 848                 if (offset < 0)
 849                         offset = 0;
 850                 prefix = COLONS + offset;
 851
 852                 /* Show the modes */
 853                 for (i = 0; i < num_parent; i++) {
 854                         printf("%s%06o", prefix, p->parent[i].mode);
 855                         prefix = " ";
 856                 }
 857                 printf("%s%06o", prefix, p->mode);
 858
 859                 /* Show sha1's */
 860                 for (i = 0; i < num_parent; i++)
 861                         printf(" %s", diff_unique_abbrev(p->parent[i].sha1,
 862                                                          opt->abbrev));
 863                 printf(" %s ", diff_unique_abbrev(p->sha1, opt->abbrev));
 864         }
 865
 866         if (opt->output_format == DIFF_FORMAT_RAW ||
 867             opt->output_format == DIFF_FORMAT_NAME_STATUS) {
 868                 for (i = 0; i < num_parent; i++)
 869                         putchar(p->parent[i].status);
 870                 putchar(inter_name_termination);
 871         }
 872
 873         if (line_termination) {
 874                 if (quote_c_style(p->path, NULL, NULL, 0))
 875                         quote_c_style(p->path, NULL, stdout, 0);
 876                 else
 877                         printf("%s", p->path);
 878                 putchar(line_termination);
 879         }
 880         else {
 881                 printf("%s%c", p->path, line_termination);
 882         }
 883 }
 884
 885 int show_combined_diff(struct combine_diff_path *p,
 886                        int num_parent,
 887                        int dense,
 888                        const char *header,
 889                        struct diff_options *opt)
 890 {
 891         if (!p->len)
 892                 return 0;
 893         switch (opt->output_format) {
 894         case DIFF_FORMAT_RAW:
 895         case DIFF_FORMAT_NAME_STATUS:
 896         case DIFF_FORMAT_NAME:
 897                 show_raw_diff(p, num_parent, header, opt);
 898                 return 1;
 899
 900         default:
 901         case DIFF_FORMAT_PATCH:
 902                 return show_patch_diff(p, num_parent, dense, header, opt);
 903         }
 904 }
 905
 906 const char *diff_tree_combined_merge(const unsigned char *sha1,
 907                              const char *header, int dense,
 908                              struct diff_options *opt)
 909 {
 910         struct commit *commit = lookup_commit(sha1);
 911         struct diff_options diffopts;
 912         struct commit_list *parents;
 913         struct combine_diff_path *p, *paths = NULL;
 914         int num_parent, i, num_paths;
 915
 916         diffopts = *opt;
 917         diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
 918         diffopts.recursive = 1;
 919
 920         /* count parents */
 921         for (parents = commit->parents, num_parent = 0;
 922              parents;
 923              parents = parents->next, num_parent++)
 924                 ; /* nothing */
 925
 926         /* find set of paths that everybody touches */
 927         for (parents = commit->parents, i = 0;
 928              parents;
 929              parents = parents->next, i++) {
 930                 struct commit *parent = parents->item;
 931                 diff_tree_sha1(parent->object.sha1, commit->object.sha1, "",
 932                                &diffopts);
 933                 diffcore_std(&diffopts);
 934                 paths = intersect_paths(paths, i, num_parent);
 935                 diff_flush(&diffopts);
 936         }
 937
 938         /* find out surviving paths */
 939         for (num_paths = 0, p = paths; p; p = p->next) {
 940                 if (p->len)
 941                         num_paths++;
 942         }
 943         if (num_paths) {
 944                 for (p = paths; p; p = p->next) {
 945                         if (show_combined_diff(p, num_parent, dense,
 946                                                header, opt))
 947                                 header = NULL;
 948                 }
 949         }
 950
 951         /* Clean things up */
 952         while (paths) {
 953                 struct combine_diff_path *tmp = paths;
 954                 paths = paths->next;
 955                 free(tmp);
 956         }
 957         return header;
 958 }