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                         hashcpy(p->sha1, q->queue[i]->two->sha1);
  35                         p->mode = q->queue[i]->two->mode;
  36                         hashcpy(p->parent[n].sha1, q->queue[i]->one->sha1);
  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                                 hashcpy(p->parent[n].sha1, q->queue[i]->one->sha1);
  60                                 p->parent[n].mode = q->queue[i]->one->mode;
  61                                 p->parent[n].status = q->queue[i]->status;
  62                                 break;
  63                         }
  64                 }
  65                 if (!found)
  66                         p->len = 0;
  67         }
  68         return curr;
  69 }
  70
  71 /* Lines lost from parent */
  72 struct lline {
  73         struct lline *next;
  74         int len;
  75         unsigned long parent_map;
  76         char line[FLEX_ARRAY];
  77 };
  78
  79 /* Lines surviving in the merge result */
  80 struct sline {
  81         struct lline *lost_head, **lost_tail;
  82         char *bol;
  83         int len;
  84         /* bit 0 up to (N-1) are on if the parent has this line (i.e.
  85          * we did not change it).
  86          * bit N is used for "interesting" lines, including context.
  87          * bit (N+1) is used for "do not show deletion before this".
  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         enum object_type type;
  97         if (is_null_sha1(sha1)) {
  98                 /* deleted blob */
  99                 *size = 0;
 100                 return xcalloc(1, 1);
 101         }
 102         blob = read_sha1_file(sha1, &type, size);
 103         if (type != OBJ_BLOB)
 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         unsigned int lno;
 147         int ob, on, nb, nn;
 148         unsigned long nmask;
 149         int num_parent;
 150         int n;
 151         struct sline *sline;
 152         struct sline *lost_bucket;
 153 };
 154
 155 static void consume_line(void *state_, char *line, unsigned long len)
 156 {
 157         struct combine_diff_state *state = state_;
 158         if (5 < len && !memcmp("@@ -", line, 4)) {
 159                 if (parse_hunk_header(line, len,
 160                                       &state->ob, &state->on,
 161                                       &state->nb, &state->nn))
 162                         return;
 163                 state->lno = state->nb;
 164                 if (!state->nb)
 165                         /* @@ -1,2 +0,0 @@ to remove the
 166                          * first two lines...
 167                          */
 168                         state->nb = 1;
 169                 if (state->nn == 0)
 170                         /* @@ -X,Y +N,0 @@ removed Y lines
 171                          * that would have come *after* line N
 172                          * in the result.  Our lost buckets hang
 173                          * to the line after the removed lines,
 174                          */
 175                         state->lost_bucket = &state->sline[state->nb];
 176                 else
 177                         state->lost_bucket = &state->sline[state->nb-1];
 178                 if (!state->sline[state->nb-1].p_lno)
 179                         state->sline[state->nb-1].p_lno =
 180                                 xcalloc(state->num_parent,
 181                                         sizeof(unsigned long));
 182                 state->sline[state->nb-1].p_lno[state->n] = state->ob;
 183                 return;
 184         }
 185         if (!state->lost_bucket)
 186                 return; /* not in any hunk yet */
 187         switch (line[0]) {
 188         case '-':
 189                 append_lost(state->lost_bucket, state->n, line+1, len-1);
 190                 break;
 191         case '+':
 192                 state->sline[state->lno-1].flag |= state->nmask;
 193                 state->lno++;
 194                 break;
 195         }
 196 }
 197
 198 static void combine_diff(const unsigned char *parent, mmfile_t *result_file,
 199                          struct sline *sline, unsigned int cnt, int n,
 200                          int num_parent)
 201 {
 202         unsigned int p_lno, lno;
 203         unsigned long nmask = (1UL << n);
 204         xpparam_t xpp;
 205         xdemitconf_t xecfg;
 206         mmfile_t parent_file;
 207         xdemitcb_t ecb;
 208         struct combine_diff_state state;
 209         unsigned long sz;
 210
 211         if (!cnt)
 212                 return; /* result deleted */
 213
 214         parent_file.ptr = grab_blob(parent, &sz);
 215         parent_file.size = sz;
 216         xpp.flags = XDF_NEED_MINIMAL;
 217         memset(&xecfg, 0, sizeof(xecfg));
 218         memset(&state, 0, sizeof(state));
 219         state.nmask = nmask;
 220         state.sline = sline;
 221         state.lno = 1;
 222         state.num_parent = num_parent;
 223         state.n = n;
 224
 225         xdi_diff_outf(&parent_file, result_file, consume_line, &state,
 226                       &xpp, &xecfg, &ecb);
 227         free(parent_file.ptr);
 228
 229         /* Assign line numbers for this parent.
 230          *
 231          * sline[lno].p_lno[n] records the first line number
 232          * (counting from 1) for parent N if the final hunk display
 233          * started by showing sline[lno] (possibly showing the lost
 234          * lines attached to it first).
 235          */
 236         for (lno = 0,  p_lno = 1; lno <= cnt; lno++) {
 237                 struct lline *ll;
 238                 sline[lno].p_lno[n] = p_lno;
 239
 240                 /* How many lines would this sline advance the p_lno? */
 241                 ll = sline[lno].lost_head;
 242                 while (ll) {
 243                         if (ll->parent_map & nmask)
 244                                 p_lno++; /* '-' means parent had it */
 245                         ll = ll->next;
 246                 }
 247                 if (lno < cnt && !(sline[lno].flag & nmask))
 248                         p_lno++; /* no '+' means parent had it */
 249         }
 250         sline[lno].p_lno[n] = p_lno; /* trailer */
 251 }
 252
 253 static unsigned long context = 3;
 254 static char combine_marker = '@';
 255
 256 static int interesting(struct sline *sline, unsigned long all_mask)
 257 {
 258         /* If some parents lost lines here, or if we have added to
 259          * some parent, it is interesting.
 260          */
 261         return ((sline->flag & all_mask) || sline->lost_head);
 262 }
 263
 264 static unsigned long adjust_hunk_tail(struct sline *sline,
 265                                       unsigned long all_mask,
 266                                       unsigned long hunk_begin,
 267                                       unsigned long i)
 268 {
 269         /* i points at the first uninteresting line.  If the last line
 270          * of the hunk was interesting only because it has some
 271          * deletion, then it is not all that interesting for the
 272          * purpose of giving trailing context lines.  This is because
 273          * we output '-' line and then unmodified sline[i-1] itself in
 274          * that case which gives us one extra context line.
 275          */
 276         if ((hunk_begin + 1 <= i) && !(sline[i-1].flag & all_mask))
 277                 i--;
 278         return i;
 279 }
 280
 281 static unsigned long find_next(struct sline *sline,
 282                                unsigned long mark,
 283                                unsigned long i,
 284                                unsigned long cnt,
 285                                int look_for_uninteresting)
 286 {
 287         /* We have examined up to i-1 and are about to look at i.
 288          * Find next interesting or uninteresting line.  Here,
 289          * "interesting" does not mean interesting(), but marked by
 290          * the give_context() function below (i.e. it includes context
 291          * lines that are not interesting to interesting() function
 292          * that are surrounded by interesting() ones.
 293          */
 294         while (i <= cnt)
 295                 if (look_for_uninteresting
 296                     ? !(sline[i].flag & mark)
 297                     : (sline[i].flag & mark))
 298                         return i;
 299                 else
 300                         i++;
 301         return i;
 302 }
 303
 304 static int give_context(struct sline *sline, unsigned long cnt, int num_parent)
 305 {
 306         unsigned long all_mask = (1UL<<num_parent) - 1;
 307         unsigned long mark = (1UL<<num_parent);
 308         unsigned long no_pre_delete = (2UL<<num_parent);
 309         unsigned long i;
 310
 311         /* Two groups of interesting lines may have a short gap of
 312          * uninteresting lines.  Connect such groups to give them a
 313          * bit of context.
 314          *
 315          * We first start from what the interesting() function says,
 316          * and mark them with "mark", and paint context lines with the
 317          * mark.  So interesting() would still say false for such context
 318          * lines but they are treated as "interesting" in the end.
 319          */
 320         i = find_next(sline, mark, 0, cnt, 0);
 321         if (cnt < i)
 322                 return 0;
 323
 324         while (i <= cnt) {
 325                 unsigned long j = (context < i) ? (i - context) : 0;
 326                 unsigned long k;
 327
 328                 /* Paint a few lines before the first interesting line. */
 329                 while (j < i)
 330                         sline[j++].flag |= mark | no_pre_delete;
 331
 332         again:
 333                 /* we know up to i is to be included.  where does the
 334                  * next uninteresting one start?
 335                  */
 336                 j = find_next(sline, mark, i, cnt, 1);
 337                 if (cnt < j)
 338                         break; /* the rest are all interesting */
 339
 340                 /* lookahead context lines */
 341                 k = find_next(sline, mark, j, cnt, 0);
 342                 j = adjust_hunk_tail(sline, all_mask, i, j);
 343
 344                 if (k < j + context) {
 345                         /* k is interesting and [j,k) are not, but
 346                          * paint them interesting because the gap is small.
 347                          */
 348                         while (j < k)
 349                                 sline[j++].flag |= mark;
 350                         i = k;
 351                         goto again;
 352                 }
 353
 354                 /* j is the first uninteresting line and there is
 355                  * no overlap beyond it within context lines.  Paint
 356                  * the trailing edge a bit.
 357                  */
 358                 i = k;
 359                 k = (j + context < cnt+1) ? j + context : cnt+1;
 360                 while (j < k)
 361                         sline[j++].flag |= mark;
 362         }
 363         return 1;
 364 }
 365
 366 static int make_hunks(struct sline *sline, unsigned long cnt,
 367                        int num_parent, int dense)
 368 {
 369         unsigned long all_mask = (1UL<<num_parent) - 1;
 370         unsigned long mark = (1UL<<num_parent);
 371         unsigned long i;
 372         int has_interesting = 0;
 373
 374         for (i = 0; i <= cnt; i++) {
 375                 if (interesting(&sline[i], all_mask))
 376                         sline[i].flag |= mark;
 377                 else
 378                         sline[i].flag &= ~mark;
 379         }
 380         if (!dense)
 381                 return give_context(sline, cnt, num_parent);
 382
 383         /* Look at each hunk, and if we have changes from only one
 384          * parent, or the changes are the same from all but one
 385          * parent, mark that uninteresting.
 386          */
 387         i = 0;
 388         while (i <= cnt) {
 389                 unsigned long j, hunk_begin, hunk_end;
 390                 unsigned long same_diff;
 391                 while (i <= cnt && !(sline[i].flag & mark))
 392                         i++;
 393                 if (cnt < i)
 394                         break; /* No more interesting hunks */
 395                 hunk_begin = i;
 396                 for (j = i + 1; j <= cnt; j++) {
 397                         if (!(sline[j].flag & mark)) {
 398                                 /* Look beyond the end to see if there
 399                                  * is an interesting line after this
 400                                  * hunk within context span.
 401                                  */
 402                                 unsigned long la; /* lookahead */
 403                                 int contin = 0;
 404                                 la = adjust_hunk_tail(sline, all_mask,
 405                                                      hunk_begin, j);
 406                                 la = (la + context < cnt + 1) ?
 407                                         (la + context) : cnt + 1;
 408                                 while (j <= --la) {
 409                                         if (sline[la].flag & mark) {
 410                                                 contin = 1;
 411                                                 break;
 412                                         }
 413                                 }
 414                                 if (!contin)
 415                                         break;
 416                                 j = la;
 417                         }
 418                 }
 419                 hunk_end = j;
 420
 421                 /* [i..hunk_end) are interesting.  Now is it really
 422                  * interesting?  We check if there are only two versions
 423                  * and the result matches one of them.  That is, we look
 424                  * at:
 425                  *   (+) line, which records lines added to which parents;
 426                  *       this line appears in the result.
 427                  *   (-) line, which records from what parents the line
 428                  *       was removed; this line does not appear in the result.
 429                  * then check the set of parents the result has difference
 430                  * from, from all lines.  If there are lines that has
 431                  * different set of parents that the result has differences
 432                  * from, that means we have more than two versions.
 433                  *
 434                  * Even when we have only two versions, if the result does
 435                  * not match any of the parents, the it should be considered
 436                  * interesting.  In such a case, we would have all '+' line.
 437                  * After passing the above "two versions" test, that would
 438                  * appear as "the same set of parents" to be "all parents".
 439                  */
 440                 same_diff = 0;
 441                 has_interesting = 0;
 442                 for (j = i; j < hunk_end && !has_interesting; j++) {
 443                         unsigned long this_diff = sline[j].flag & all_mask;
 444                         struct lline *ll = sline[j].lost_head;
 445                         if (this_diff) {
 446                                 /* This has some changes.  Is it the
 447                                  * same as others?
 448                                  */
 449                                 if (!same_diff)
 450                                         same_diff = this_diff;
 451                                 else if (same_diff != this_diff) {
 452                                         has_interesting = 1;
 453                                         break;
 454                                 }
 455                         }
 456                         while (ll && !has_interesting) {
 457                                 /* Lost this line from these parents;
 458                                  * who are they?  Are they the same?
 459                                  */
 460                                 this_diff = ll->parent_map;
 461                                 if (!same_diff)
 462                                         same_diff = this_diff;
 463                                 else if (same_diff != this_diff) {
 464                                         has_interesting = 1;
 465                                 }
 466                                 ll = ll->next;
 467                         }
 468                 }
 469
 470                 if (!has_interesting && same_diff != all_mask) {
 471                         /* This hunk is not that interesting after all */
 472                         for (j = hunk_begin; j < hunk_end; j++)
 473                                 sline[j].flag &= ~mark;
 474                 }
 475                 i = hunk_end;
 476         }
 477
 478         has_interesting = give_context(sline, cnt, num_parent);
 479         return has_interesting;
 480 }
 481
 482 static void show_parent_lno(struct sline *sline, unsigned long l0, unsigned long l1, int n, unsigned long null_context)
 483 {
 484         l0 = sline[l0].p_lno[n];
 485         l1 = sline[l1].p_lno[n];
 486         printf(" -%lu,%lu", l0, l1-l0-null_context);
 487 }
 488
 489 static int hunk_comment_line(const char *bol)
 490 {
 491         int ch;
 492
 493         if (!bol)
 494                 return 0;
 495         ch = *bol & 0xff;
 496         return (isalpha(ch) || ch == '_' || ch == '$');
 497 }
 498
 499 static void dump_sline(struct sline *sline, unsigned long cnt, int num_parent,
 500                        int use_color)
 501 {
 502         unsigned long mark = (1UL<<num_parent);
 503         unsigned long no_pre_delete = (2UL<<num_parent);
 504         int i;
 505         unsigned long lno = 0;
 506         const char *c_frag = diff_get_color(use_color, DIFF_FRAGINFO);
 507         const char *c_new = diff_get_color(use_color, DIFF_FILE_NEW);
 508         const char *c_old = diff_get_color(use_color, DIFF_FILE_OLD);
 509         const char *c_plain = diff_get_color(use_color, DIFF_PLAIN);
 510         const char *c_reset = diff_get_color(use_color, DIFF_RESET);
 511
 512         if (!cnt)
 513                 return; /* result deleted */
 514
 515         while (1) {
 516                 struct sline *sl = &sline[lno];
 517                 unsigned long hunk_end;
 518                 unsigned long rlines;
 519                 const char *hunk_comment = NULL;
 520                 unsigned long null_context = 0;
 521
 522                 while (lno <= cnt && !(sline[lno].flag & mark)) {
 523                         if (hunk_comment_line(sline[lno].bol))
 524                                 hunk_comment = sline[lno].bol;
 525                         lno++;
 526                 }
 527                 if (cnt < lno)
 528                         break;
 529                 else {
 530                         for (hunk_end = lno + 1; hunk_end <= cnt; hunk_end++)
 531                                 if (!(sline[hunk_end].flag & mark))
 532                                         break;
 533                 }
 534                 rlines = hunk_end - lno;
 535                 if (cnt < hunk_end)
 536                         rlines--; /* pointing at the last delete hunk */
 537
 538                 if (!context) {
 539                         /*
 540                          * Even when running with --unified=0, all
 541                          * lines in the hunk needs to be processed in
 542                          * the loop below in order to show the
 543                          * deletion recorded in lost_head.  However,
 544                          * we do not want to show the resulting line
 545                          * with all blank context markers in such a
 546                          * case.  Compensate.
 547                          */
 548                         unsigned long j;
 549                         for (j = lno; j < hunk_end; j++)
 550                                 if (!(sline[j].flag & (mark-1)))
 551                                         null_context++;
 552                         rlines -= null_context;
 553                 }
 554
 555                 fputs(c_frag, stdout);
 556                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 557                 for (i = 0; i < num_parent; i++)
 558                         show_parent_lno(sline, lno, hunk_end, i, null_context);
 559                 printf(" +%lu,%lu ", lno+1, rlines);
 560                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 561
 562                 if (hunk_comment) {
 563                         int comment_end = 0;
 564                         for (i = 0; i < 40; i++) {
 565                                 int ch = hunk_comment[i] & 0xff;
 566                                 if (!ch || ch == '\n')
 567                                         break;
 568                                 if (!isspace(ch))
 569                                     comment_end = i;
 570                         }
 571                         if (comment_end)
 572                                 putchar(' ');
 573                         for (i = 0; i < comment_end; i++)
 574                                 putchar(hunk_comment[i]);
 575                 }
 576
 577                 printf("%s\n", c_reset);
 578                 while (lno < hunk_end) {
 579                         struct lline *ll;
 580                         int j;
 581                         unsigned long p_mask;
 582                         sl = &sline[lno++];
 583                         ll = (sl->flag & no_pre_delete) ? NULL : sl->lost_head;
 584                         while (ll) {
 585                                 fputs(c_old, stdout);
 586                                 for (j = 0; j < num_parent; j++) {
 587                                         if (ll->parent_map & (1UL<<j))
 588                                                 putchar('-');
 589                                         else
 590                                                 putchar(' ');
 591                                 }
 592                                 printf("%s%s\n", ll->line, c_reset);
 593                                 ll = ll->next;
 594                         }
 595                         if (cnt < lno)
 596                                 break;
 597                         p_mask = 1;
 598                         if (!(sl->flag & (mark-1))) {
 599                                 /*
 600                                  * This sline was here to hang the
 601                                  * lost lines in front of it.
 602                                  */
 603                                 if (!context)
 604                                         continue;
 605                                 fputs(c_plain, stdout);
 606                         }
 607                         else
 608                                 fputs(c_new, stdout);
 609                         for (j = 0; j < num_parent; j++) {
 610                                 if (p_mask & sl->flag)
 611                                         putchar('+');
 612                                 else
 613                                         putchar(' ');
 614                                 p_mask <<= 1;
 615                         }
 616                         printf("%.*s%s\n", sl->len, sl->bol, c_reset);
 617                 }
 618         }
 619 }
 620
 621 static void reuse_combine_diff(struct sline *sline, unsigned long cnt,
 622                                int i, int j)
 623 {
 624         /* We have already examined parent j and we know parent i
 625          * and parent j are the same, so reuse the combined result
 626          * of parent j for parent i.
 627          */
 628         unsigned long lno, imask, jmask;
 629         imask = (1UL<<i);
 630         jmask = (1UL<<j);
 631
 632         for (lno = 0; lno <= cnt; lno++) {
 633                 struct lline *ll = sline->lost_head;
 634                 sline->p_lno[i] = sline->p_lno[j];
 635                 while (ll) {
 636                         if (ll->parent_map & jmask)
 637                                 ll->parent_map |= imask;
 638                         ll = ll->next;
 639                 }
 640                 if (sline->flag & jmask)
 641                         sline->flag |= imask;
 642                 sline++;
 643         }
 644         /* the overall size of the file (sline[cnt]) */
 645         sline->p_lno[i] = sline->p_lno[j];
 646 }
 647
 648 static void dump_quoted_path(const char *head,
 649                              const char *prefix,
 650                              const char *path,
 651                              const char *c_meta, const char *c_reset)
 652 {
 653         static struct strbuf buf = STRBUF_INIT;
 654
 655         strbuf_reset(&buf);
 656         strbuf_addstr(&buf, c_meta);
 657         strbuf_addstr(&buf, head);
 658         quote_two_c_style(&buf, prefix, path, 0);
 659         strbuf_addstr(&buf, c_reset);
 660         puts(buf.buf);
 661 }
 662
 663 static void show_patch_diff(struct combine_diff_path *elem, int num_parent,
 664                             int dense, struct rev_info *rev)
 665 {
 666         struct diff_options *opt = &rev->diffopt;
 667         unsigned long result_size, cnt, lno;
 668         char *result, *cp;
 669         struct sline *sline; /* survived lines */
 670         int mode_differs = 0;
 671         int i, show_hunks;
 672         int working_tree_file = is_null_sha1(elem->sha1);
 673         int abbrev = DIFF_OPT_TST(opt, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
 674         mmfile_t result_file;
 675
 676         context = opt->context;
 677         /* Read the result of merge first */
 678         if (!working_tree_file)
 679                 result = grab_blob(elem->sha1, &result_size);
 680         else {
 681                 /* Used by diff-tree to read from the working tree */
 682                 struct stat st;
 683                 int fd = -1;
 684
 685                 if (lstat(elem->path, &st) < 0)
 686                         goto deleted_file;
 687
 688                 if (S_ISLNK(st.st_mode)) {
 689                         size_t len = xsize_t(st.st_size);
 690                         result_size = len;
 691                         result = xmalloc(len + 1);
 692                         if (result_size != readlink(elem->path, result, len)) {
 693                                 error("readlink(%s): %s", elem->path,
 694                                       strerror(errno));
 695                                 return;
 696                         }
 697                         result[len] = 0;
 698                         elem->mode = canon_mode(st.st_mode);
 699                 }
 700                 else if (0 <= (fd = open(elem->path, O_RDONLY)) &&
 701                          !fstat(fd, &st)) {
 702                         size_t len = xsize_t(st.st_size);
 703                         ssize_t done;
 704                         int is_file, i;
 705
 706                         elem->mode = canon_mode(st.st_mode);
 707                         /* if symlinks don't work, assume symlink if all parents
 708                          * are symlinks
 709                          */
 710                         is_file = has_symlinks;
 711                         for (i = 0; !is_file && i < num_parent; i++)
 712                                 is_file = !S_ISLNK(elem->parent[i].mode);
 713                         if (!is_file)
 714                                 elem->mode = canon_mode(S_IFLNK);
 715
 716                         result_size = len;
 717                         result = xmalloc(len + 1);
 718
 719                         done = read_in_full(fd, result, len);
 720                         if (done < 0)
 721                                 die("read error '%s'", elem->path);
 722                         else if (done < len)
 723                                 die("early EOF '%s'", elem->path);
 724
 725                         result[len] = 0;
 726
 727                         /* If not a fake symlink, apply filters, e.g. autocrlf */
 728                         if (is_file) {
 729                                 struct strbuf buf;
 730
 731                                 strbuf_init(&buf, 0);
 732                                 if (convert_to_git(elem->path, result, len, &buf, safe_crlf)) {
 733                                         free(result);
 734                                         result = strbuf_detach(&buf, &len);
 735                                         result_size = len;
 736                                 }
 737                         }
 738                 }
 739                 else {
 740                 deleted_file:
 741                         result_size = 0;
 742                         elem->mode = 0;
 743                         result = xcalloc(1, 1);
 744                 }
 745
 746                 if (0 <= fd)
 747                         close(fd);
 748         }
 749
 750         for (cnt = 0, cp = result; cp < result + result_size; cp++) {
 751                 if (*cp == '\n')
 752                         cnt++;
 753         }
 754         if (result_size && result[result_size-1] != '\n')
 755                 cnt++; /* incomplete line */
 756
 757         sline = xcalloc(cnt+2, sizeof(*sline));
 758         sline[0].bol = result;
 759         for (lno = 0; lno <= cnt + 1; lno++) {
 760                 sline[lno].lost_tail = &sline[lno].lost_head;
 761                 sline[lno].flag = 0;
 762         }
 763         for (lno = 0, cp = result; cp < result + result_size; cp++) {
 764                 if (*cp == '\n') {
 765                         sline[lno].len = cp - sline[lno].bol;
 766                         lno++;
 767                         if (lno < cnt)
 768                                 sline[lno].bol = cp + 1;
 769                 }
 770         }
 771         if (result_size && result[result_size-1] != '\n')
 772                 sline[cnt-1].len = result_size - (sline[cnt-1].bol - result);
 773
 774         result_file.ptr = result;
 775         result_file.size = result_size;
 776
 777         /* Even p_lno[cnt+1] is valid -- that is for the end line number
 778          * for deletion hunk at the end.
 779          */
 780         sline[0].p_lno = xcalloc((cnt+2) * num_parent, sizeof(unsigned long));
 781         for (lno = 0; lno <= cnt; lno++)
 782                 sline[lno+1].p_lno = sline[lno].p_lno + num_parent;
 783
 784         for (i = 0; i < num_parent; i++) {
 785                 int j;
 786                 for (j = 0; j < i; j++) {
 787                         if (!hashcmp(elem->parent[i].sha1,
 788                                      elem->parent[j].sha1)) {
 789                                 reuse_combine_diff(sline, cnt, i, j);
 790                                 break;
 791                         }
 792                 }
 793                 if (i <= j)
 794                         combine_diff(elem->parent[i].sha1, &result_file, sline,
 795                                      cnt, i, num_parent);
 796                 if (elem->parent[i].mode != elem->mode)
 797                         mode_differs = 1;
 798         }
 799
 800         show_hunks = make_hunks(sline, cnt, num_parent, dense);
 801
 802         if (show_hunks || mode_differs || working_tree_file) {
 803                 const char *abb;
 804                 int use_color = DIFF_OPT_TST(opt, COLOR_DIFF);
 805                 const char *c_meta = diff_get_color(use_color, DIFF_METAINFO);
 806                 const char *c_reset = diff_get_color(use_color, DIFF_RESET);
 807                 int added = 0;
 808                 int deleted = 0;
 809
 810                 if (rev->loginfo && !rev->no_commit_id)
 811                         show_log(rev);
 812                 dump_quoted_path(dense ? "diff --cc " : "diff --combined ",
 813                                  "", elem->path, c_meta, c_reset);
 814                 printf("%sindex ", c_meta);
 815                 for (i = 0; i < num_parent; i++) {
 816                         abb = find_unique_abbrev(elem->parent[i].sha1,
 817                                                  abbrev);
 818                         printf("%s%s", i ? "," : "", abb);
 819                 }
 820                 abb = find_unique_abbrev(elem->sha1, abbrev);
 821                 printf("..%s%s\n", abb, c_reset);
 822
 823                 if (mode_differs) {
 824                         deleted = !elem->mode;
 825
 826                         /* We say it was added if nobody had it */
 827                         added = !deleted;
 828                         for (i = 0; added && i < num_parent; i++)
 829                                 if (elem->parent[i].status !=
 830                                     DIFF_STATUS_ADDED)
 831                                         added = 0;
 832                         if (added)
 833                                 printf("%snew file mode %06o",
 834                                        c_meta, elem->mode);
 835                         else {
 836                                 if (deleted)
 837                                         printf("%sdeleted file ", c_meta);
 838                                 printf("mode ");
 839                                 for (i = 0; i < num_parent; i++) {
 840                                         printf("%s%06o", i ? "," : "",
 841                                                elem->parent[i].mode);
 842                                 }
 843                                 if (elem->mode)
 844                                         printf("..%06o", elem->mode);
 845                         }
 846                         printf("%s\n", c_reset);
 847                 }
 848                 if (added)
 849                         dump_quoted_path("--- ", "", "/dev/null",
 850                                          c_meta, c_reset);
 851                 else
 852                         dump_quoted_path("--- ", opt->a_prefix, elem->path,
 853                                          c_meta, c_reset);
 854                 if (deleted)
 855                         dump_quoted_path("+++ ", "", "/dev/null",
 856                                          c_meta, c_reset);
 857                 else
 858                         dump_quoted_path("+++ ", opt->b_prefix, elem->path,
 859                                          c_meta, c_reset);
 860                 dump_sline(sline, cnt, num_parent,
 861                            DIFF_OPT_TST(opt, COLOR_DIFF));
 862         }
 863         free(result);
 864
 865         for (lno = 0; lno < cnt; lno++) {
 866                 if (sline[lno].lost_head) {
 867                         struct lline *ll = sline[lno].lost_head;
 868                         while (ll) {
 869                                 struct lline *tmp = ll;
 870                                 ll = ll->next;
 871                                 free(tmp);
 872                         }
 873                 }
 874         }
 875         free(sline[0].p_lno);
 876         free(sline);
 877 }
 878
 879 #define COLONS "::::::::::::::::::::::::::::::::"
 880
 881 static void show_raw_diff(struct combine_diff_path *p, int num_parent, struct rev_info *rev)
 882 {
 883         struct diff_options *opt = &rev->diffopt;
 884         int i, offset;
 885         const char *prefix;
 886         int line_termination, inter_name_termination;
 887
 888         line_termination = opt->line_termination;
 889         inter_name_termination = '\t';
 890         if (!line_termination)
 891                 inter_name_termination = 0;
 892
 893         if (rev->loginfo && !rev->no_commit_id)
 894                 show_log(rev);
 895
 896         if (opt->output_format & DIFF_FORMAT_RAW) {
 897                 offset = strlen(COLONS) - num_parent;
 898                 if (offset < 0)
 899                         offset = 0;
 900                 prefix = COLONS + offset;
 901
 902                 /* Show the modes */
 903                 for (i = 0; i < num_parent; i++) {
 904                         printf("%s%06o", prefix, p->parent[i].mode);
 905                         prefix = " ";
 906                 }
 907                 printf("%s%06o", prefix, p->mode);
 908
 909                 /* Show sha1's */
 910                 for (i = 0; i < num_parent; i++)
 911                         printf(" %s", diff_unique_abbrev(p->parent[i].sha1,
 912                                                          opt->abbrev));
 913                 printf(" %s ", diff_unique_abbrev(p->sha1, opt->abbrev));
 914         }
 915
 916         if (opt->output_format & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS)) {
 917                 for (i = 0; i < num_parent; i++)
 918                         putchar(p->parent[i].status);
 919                 putchar(inter_name_termination);
 920         }
 921
 922         write_name_quoted(p->path, stdout, line_termination);
 923 }
 924
 925 void show_combined_diff(struct combine_diff_path *p,
 926                        int num_parent,
 927                        int dense,
 928                        struct rev_info *rev)
 929 {
 930         struct diff_options *opt = &rev->diffopt;
 931         if (!p->len)
 932                 return;
 933         if (opt->output_format & (DIFF_FORMAT_RAW |
 934                                   DIFF_FORMAT_NAME |
 935                                   DIFF_FORMAT_NAME_STATUS))
 936                 show_raw_diff(p, num_parent, rev);
 937         else if (opt->output_format & DIFF_FORMAT_PATCH)
 938                 show_patch_diff(p, num_parent, dense, rev);
 939 }
 940
 941 void diff_tree_combined(const unsigned char *sha1,
 942                         const unsigned char parent[][20],
 943                         int num_parent,
 944                         int dense,
 945                         struct rev_info *rev)
 946 {
 947         struct diff_options *opt = &rev->diffopt;
 948         struct diff_options diffopts;
 949         struct combine_diff_path *p, *paths = NULL;
 950         int i, num_paths, needsep, show_log_first;
 951
 952         diffopts = *opt;
 953         diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
 954         DIFF_OPT_SET(&diffopts, RECURSIVE);
 955         DIFF_OPT_CLR(&diffopts, ALLOW_EXTERNAL);
 956
 957         show_log_first = !!rev->loginfo && !rev->no_commit_id;
 958         needsep = 0;
 959         /* find set of paths that everybody touches */
 960         for (i = 0; i < num_parent; i++) {
 961                 /* show stat against the first parent even
 962                  * when doing combined diff.
 963                  */
 964                 int stat_opt = (opt->output_format &
 965                                 (DIFF_FORMAT_NUMSTAT|DIFF_FORMAT_DIFFSTAT));
 966                 if (i == 0 && stat_opt)
 967                         diffopts.output_format = stat_opt;
 968                 else
 969                         diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
 970                 diff_tree_sha1(parent[i], sha1, "", &diffopts);
 971                 diffcore_std(&diffopts);
 972                 paths = intersect_paths(paths, i, num_parent);
 973
 974                 if (show_log_first && i == 0) {
 975                         show_log(rev);
 976                         if (rev->verbose_header && opt->output_format)
 977                                 putchar(opt->line_termination);
 978                 }
 979                 diff_flush(&diffopts);
 980         }
 981
 982         /* find out surviving paths */
 983         for (num_paths = 0, p = paths; p; p = p->next) {
 984                 if (p->len)
 985                         num_paths++;
 986         }
 987         if (num_paths) {
 988                 if (opt->output_format & (DIFF_FORMAT_RAW |
 989                                           DIFF_FORMAT_NAME |
 990                                           DIFF_FORMAT_NAME_STATUS)) {
 991                         for (p = paths; p; p = p->next) {
 992                                 if (p->len)
 993                                         show_raw_diff(p, num_parent, rev);
 994                         }
 995                         needsep = 1;
 996                 }
 997                 else if (opt->output_format &
 998                          (DIFF_FORMAT_NUMSTAT|DIFF_FORMAT_DIFFSTAT))
 999                         needsep = 1;
1000                 if (opt->output_format & DIFF_FORMAT_PATCH) {
1001                         if (needsep)
1002                                 putchar(opt->line_termination);
1003                         for (p = paths; p; p = p->next) {
1004                                 if (p->len)
1005                                         show_patch_diff(p, num_parent, dense,
1006                                                         rev);
1007                         }
1008                 }
1009         }
1010
1011         /* Clean things up */
1012         while (paths) {
1013                 struct combine_diff_path *tmp = paths;
1014                 paths = paths->next;
1015                 free(tmp);
1016         }
1017 }
1018
1019 void diff_tree_combined_merge(const unsigned char *sha1,
1020                              int dense, struct rev_info *rev)
1021 {
1022         int num_parent;
1023         const unsigned char (*parent)[20];
1024         struct commit *commit = lookup_commit(sha1);
1025         struct commit_list *parents;
1026
1027         /* count parents */
1028         for (parents = commit->parents, num_parent = 0;
1029              parents;
1030              parents = parents->next, num_parent++)
1031                 ; /* nothing */
1032
1033         parent = xmalloc(num_parent * sizeof(*parent));
1034         for (parents = commit->parents, num_parent = 0;
1035              parents;
1036              parents = parents->next, num_parent++)
1037                 hashcpy((unsigned char*)(parent + num_parent),
1038                         parents->item->object.sha1);
1039         diff_tree_combined(sha1, parent, num_parent, dense, rev);
1040 }