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

   1 #include "cache.h"
   2 #include "commit.h"
   3 #include "blob.h"
   4 #include "diff.h"
   5 #include "diffcore.h"
   6 #include "quote.h"
   7 #include "xdiff-interface.h"
   8 #include "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         memset(&xpp, 0, sizeof(xpp));
 217         xpp.flags = XDF_NEED_MINIMAL;
 218         memset(&xecfg, 0, sizeof(xecfg));
 219         memset(&state, 0, sizeof(state));
 220         state.nmask = nmask;
 221         state.sline = sline;
 222         state.lno = 1;
 223         state.num_parent = num_parent;
 224         state.n = n;
 225
 226         xdi_diff_outf(&parent_file, result_file, consume_line, &state,
 227                       &xpp, &xecfg, &ecb);
 228         free(parent_file.ptr);
 229
 230         /* Assign line numbers for this parent.
 231          *
 232          * sline[lno].p_lno[n] records the first line number
 233          * (counting from 1) for parent N if the final hunk display
 234          * started by showing sline[lno] (possibly showing the lost
 235          * lines attached to it first).
 236          */
 237         for (lno = 0,  p_lno = 1; lno <= cnt; lno++) {
 238                 struct lline *ll;
 239                 sline[lno].p_lno[n] = p_lno;
 240
 241                 /* How many lines would this sline advance the p_lno? */
 242                 ll = sline[lno].lost_head;
 243                 while (ll) {
 244                         if (ll->parent_map & nmask)
 245                                 p_lno++; /* '-' means parent had it */
 246                         ll = ll->next;
 247                 }
 248                 if (lno < cnt && !(sline[lno].flag & nmask))
 249                         p_lno++; /* no '+' means parent had it */
 250         }
 251         sline[lno].p_lno[n] = p_lno; /* trailer */
 252 }
 253
 254 static unsigned long context = 3;
 255 static char combine_marker = '@';
 256
 257 static int interesting(struct sline *sline, unsigned long all_mask)
 258 {
 259         /* If some parents lost lines here, or if we have added to
 260          * some parent, it is interesting.
 261          */
 262         return ((sline->flag & all_mask) || sline->lost_head);
 263 }
 264
 265 static unsigned long adjust_hunk_tail(struct sline *sline,
 266                                       unsigned long all_mask,
 267                                       unsigned long hunk_begin,
 268                                       unsigned long i)
 269 {
 270         /* i points at the first uninteresting line.  If the last line
 271          * of the hunk was interesting only because it has some
 272          * deletion, then it is not all that interesting for the
 273          * purpose of giving trailing context lines.  This is because
 274          * we output '-' line and then unmodified sline[i-1] itself in
 275          * that case which gives us one extra context line.
 276          */
 277         if ((hunk_begin + 1 <= i) && !(sline[i-1].flag & all_mask))
 278                 i--;
 279         return i;
 280 }
 281
 282 static unsigned long find_next(struct sline *sline,
 283                                unsigned long mark,
 284                                unsigned long i,
 285                                unsigned long cnt,
 286                                int look_for_uninteresting)
 287 {
 288         /* We have examined up to i-1 and are about to look at i.
 289          * Find next interesting or uninteresting line.  Here,
 290          * "interesting" does not mean interesting(), but marked by
 291          * the give_context() function below (i.e. it includes context
 292          * lines that are not interesting to interesting() function
 293          * that are surrounded by interesting() ones.
 294          */
 295         while (i <= cnt)
 296                 if (look_for_uninteresting
 297                     ? !(sline[i].flag & mark)
 298                     : (sline[i].flag & mark))
 299                         return i;
 300                 else
 301                         i++;
 302         return i;
 303 }
 304
 305 static int give_context(struct sline *sline, unsigned long cnt, int num_parent)
 306 {
 307         unsigned long all_mask = (1UL<<num_parent) - 1;
 308         unsigned long mark = (1UL<<num_parent);
 309         unsigned long no_pre_delete = (2UL<<num_parent);
 310         unsigned long i;
 311
 312         /* Two groups of interesting lines may have a short gap of
 313          * uninteresting lines.  Connect such groups to give them a
 314          * bit of context.
 315          *
 316          * We first start from what the interesting() function says,
 317          * and mark them with "mark", and paint context lines with the
 318          * mark.  So interesting() would still say false for such context
 319          * lines but they are treated as "interesting" in the end.
 320          */
 321         i = find_next(sline, mark, 0, cnt, 0);
 322         if (cnt < i)
 323                 return 0;
 324
 325         while (i <= cnt) {
 326                 unsigned long j = (context < i) ? (i - context) : 0;
 327                 unsigned long k;
 328
 329                 /* Paint a few lines before the first interesting line. */
 330                 while (j < i)
 331                         sline[j++].flag |= mark | no_pre_delete;
 332
 333         again:
 334                 /* we know up to i is to be included.  where does the
 335                  * next uninteresting one start?
 336                  */
 337                 j = find_next(sline, mark, i, cnt, 1);
 338                 if (cnt < j)
 339                         break; /* the rest are all interesting */
 340
 341                 /* lookahead context lines */
 342                 k = find_next(sline, mark, j, cnt, 0);
 343                 j = adjust_hunk_tail(sline, all_mask, i, j);
 344
 345                 if (k < j + context) {
 346                         /* k is interesting and [j,k) are not, but
 347                          * paint them interesting because the gap is small.
 348                          */
 349                         while (j < k)
 350                                 sline[j++].flag |= mark;
 351                         i = k;
 352                         goto again;
 353                 }
 354
 355                 /* j is the first uninteresting line and there is
 356                  * no overlap beyond it within context lines.  Paint
 357                  * the trailing edge a bit.
 358                  */
 359                 i = k;
 360                 k = (j + context < cnt+1) ? j + context : cnt+1;
 361                 while (j < k)
 362                         sline[j++].flag |= mark;
 363         }
 364         return 1;
 365 }
 366
 367 static int make_hunks(struct sline *sline, unsigned long cnt,
 368                        int num_parent, int dense)
 369 {
 370         unsigned long all_mask = (1UL<<num_parent) - 1;
 371         unsigned long mark = (1UL<<num_parent);
 372         unsigned long i;
 373         int has_interesting = 0;
 374
 375         for (i = 0; i <= cnt; i++) {
 376                 if (interesting(&sline[i], all_mask))
 377                         sline[i].flag |= mark;
 378                 else
 379                         sline[i].flag &= ~mark;
 380         }
 381         if (!dense)
 382                 return give_context(sline, cnt, num_parent);
 383
 384         /* Look at each hunk, and if we have changes from only one
 385          * parent, or the changes are the same from all but one
 386          * parent, mark that uninteresting.
 387          */
 388         i = 0;
 389         while (i <= cnt) {
 390                 unsigned long j, hunk_begin, hunk_end;
 391                 unsigned long same_diff;
 392                 while (i <= cnt && !(sline[i].flag & mark))
 393                         i++;
 394                 if (cnt < i)
 395                         break; /* No more interesting hunks */
 396                 hunk_begin = i;
 397                 for (j = i + 1; j <= cnt; j++) {
 398                         if (!(sline[j].flag & mark)) {
 399                                 /* Look beyond the end to see if there
 400                                  * is an interesting line after this
 401                                  * hunk within context span.
 402                                  */
 403                                 unsigned long la; /* lookahead */
 404                                 int contin = 0;
 405                                 la = adjust_hunk_tail(sline, all_mask,
 406                                                      hunk_begin, j);
 407                                 la = (la + context < cnt + 1) ?
 408                                         (la + context) : cnt + 1;
 409                                 while (j <= --la) {
 410                                         if (sline[la].flag & mark) {
 411                                                 contin = 1;
 412                                                 break;
 413                                         }
 414                                 }
 415                                 if (!contin)
 416                                         break;
 417                                 j = la;
 418                         }
 419                 }
 420                 hunk_end = j;
 421
 422                 /* [i..hunk_end) are interesting.  Now is it really
 423                  * interesting?  We check if there are only two versions
 424                  * and the result matches one of them.  That is, we look
 425                  * at:
 426                  *   (+) line, which records lines added to which parents;
 427                  *       this line appears in the result.
 428                  *   (-) line, which records from what parents the line
 429                  *       was removed; this line does not appear in the result.
 430                  * then check the set of parents the result has difference
 431                  * from, from all lines.  If there are lines that has
 432                  * different set of parents that the result has differences
 433                  * from, that means we have more than two versions.
 434                  *
 435                  * Even when we have only two versions, if the result does
 436                  * not match any of the parents, the it should be considered
 437                  * interesting.  In such a case, we would have all '+' line.
 438                  * After passing the above "two versions" test, that would
 439                  * appear as "the same set of parents" to be "all parents".
 440                  */
 441                 same_diff = 0;
 442                 has_interesting = 0;
 443                 for (j = i; j < hunk_end && !has_interesting; j++) {
 444                         unsigned long this_diff = sline[j].flag & all_mask;
 445                         struct lline *ll = sline[j].lost_head;
 446                         if (this_diff) {
 447                                 /* This has some changes.  Is it the
 448                                  * same as others?
 449                                  */
 450                                 if (!same_diff)
 451                                         same_diff = this_diff;
 452                                 else if (same_diff != this_diff) {
 453                                         has_interesting = 1;
 454                                         break;
 455                                 }
 456                         }
 457                         while (ll && !has_interesting) {
 458                                 /* Lost this line from these parents;
 459                                  * who are they?  Are they the same?
 460                                  */
 461                                 this_diff = ll->parent_map;
 462                                 if (!same_diff)
 463                                         same_diff = this_diff;
 464                                 else if (same_diff != this_diff) {
 465                                         has_interesting = 1;
 466                                 }
 467                                 ll = ll->next;
 468                         }
 469                 }
 470
 471                 if (!has_interesting && same_diff != all_mask) {
 472                         /* This hunk is not that interesting after all */
 473                         for (j = hunk_begin; j < hunk_end; j++)
 474                                 sline[j].flag &= ~mark;
 475                 }
 476                 i = hunk_end;
 477         }
 478
 479         has_interesting = give_context(sline, cnt, num_parent);
 480         return has_interesting;
 481 }
 482
 483 static void show_parent_lno(struct sline *sline, unsigned long l0, unsigned long l1, int n, unsigned long null_context)
 484 {
 485         l0 = sline[l0].p_lno[n];
 486         l1 = sline[l1].p_lno[n];
 487         printf(" -%lu,%lu", l0, l1-l0-null_context);
 488 }
 489
 490 static int hunk_comment_line(const char *bol)
 491 {
 492         int ch;
 493
 494         if (!bol)
 495                 return 0;
 496         ch = *bol & 0xff;
 497         return (isalpha(ch) || ch == '_' || ch == '$');
 498 }
 499
 500 static void show_line_to_eol(const char *line, int len, const char *reset)
 501 {
 502         int saw_cr_at_eol = 0;
 503         if (len < 0)
 504                 len = strlen(line);
 505         saw_cr_at_eol = (len && line[len-1] == '\r');
 506
 507         printf("%.*s%s%s\n", len - saw_cr_at_eol, line,
 508                reset,
 509                saw_cr_at_eol ? "\r" : "");
 510 }
 511
 512 static void dump_sline(struct sline *sline, unsigned long cnt, int num_parent,
 513                        int use_color)
 514 {
 515         unsigned long mark = (1UL<<num_parent);
 516         unsigned long no_pre_delete = (2UL<<num_parent);
 517         int i;
 518         unsigned long lno = 0;
 519         const char *c_frag = diff_get_color(use_color, DIFF_FRAGINFO);
 520         const char *c_new = diff_get_color(use_color, DIFF_FILE_NEW);
 521         const char *c_old = diff_get_color(use_color, DIFF_FILE_OLD);
 522         const char *c_plain = diff_get_color(use_color, DIFF_PLAIN);
 523         const char *c_reset = diff_get_color(use_color, DIFF_RESET);
 524
 525         if (!cnt)
 526                 return; /* result deleted */
 527
 528         while (1) {
 529                 unsigned long hunk_end;
 530                 unsigned long rlines;
 531                 const char *hunk_comment = NULL;
 532                 unsigned long null_context = 0;
 533
 534                 while (lno <= cnt && !(sline[lno].flag & mark)) {
 535                         if (hunk_comment_line(sline[lno].bol))
 536                                 hunk_comment = sline[lno].bol;
 537                         lno++;
 538                 }
 539                 if (cnt < lno)
 540                         break;
 541                 else {
 542                         for (hunk_end = lno + 1; hunk_end <= cnt; hunk_end++)
 543                                 if (!(sline[hunk_end].flag & mark))
 544                                         break;
 545                 }
 546                 rlines = hunk_end - lno;
 547                 if (cnt < hunk_end)
 548                         rlines--; /* pointing at the last delete hunk */
 549
 550                 if (!context) {
 551                         /*
 552                          * Even when running with --unified=0, all
 553                          * lines in the hunk needs to be processed in
 554                          * the loop below in order to show the
 555                          * deletion recorded in lost_head.  However,
 556                          * we do not want to show the resulting line
 557                          * with all blank context markers in such a
 558                          * case.  Compensate.
 559                          */
 560                         unsigned long j;
 561                         for (j = lno; j < hunk_end; j++)
 562                                 if (!(sline[j].flag & (mark-1)))
 563                                         null_context++;
 564                         rlines -= null_context;
 565                 }
 566
 567                 fputs(c_frag, stdout);
 568                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 569                 for (i = 0; i < num_parent; i++)
 570                         show_parent_lno(sline, lno, hunk_end, i, null_context);
 571                 printf(" +%lu,%lu ", lno+1, rlines);
 572                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 573
 574                 if (hunk_comment) {
 575                         int comment_end = 0;
 576                         for (i = 0; i < 40; i++) {
 577                                 int ch = hunk_comment[i] & 0xff;
 578                                 if (!ch || ch == '\n')
 579                                         break;
 580                                 if (!isspace(ch))
 581                                     comment_end = i;
 582                         }
 583                         if (comment_end)
 584                                 putchar(' ');
 585                         for (i = 0; i < comment_end; i++)
 586                                 putchar(hunk_comment[i]);
 587                 }
 588
 589                 printf("%s\n", c_reset);
 590                 while (lno < hunk_end) {
 591                         struct lline *ll;
 592                         int j;
 593                         unsigned long p_mask;
 594                         struct sline *sl = &sline[lno++];
 595                         ll = (sl->flag & no_pre_delete) ? NULL : sl->lost_head;
 596                         while (ll) {
 597                                 fputs(c_old, stdout);
 598                                 for (j = 0; j < num_parent; j++) {
 599                                         if (ll->parent_map & (1UL<<j))
 600                                                 putchar('-');
 601                                         else
 602                                                 putchar(' ');
 603                                 }
 604                                 show_line_to_eol(ll->line, -1, c_reset);
 605                                 ll = ll->next;
 606                         }
 607                         if (cnt < lno)
 608                                 break;
 609                         p_mask = 1;
 610                         if (!(sl->flag & (mark-1))) {
 611                                 /*
 612                                  * This sline was here to hang the
 613                                  * lost lines in front of it.
 614                                  */
 615                                 if (!context)
 616                                         continue;
 617                                 fputs(c_plain, stdout);
 618                         }
 619                         else
 620                                 fputs(c_new, stdout);
 621                         for (j = 0; j < num_parent; j++) {
 622                                 if (p_mask & sl->flag)
 623                                         putchar('+');
 624                                 else
 625                                         putchar(' ');
 626                                 p_mask <<= 1;
 627                         }
 628                         show_line_to_eol(sl->bol, sl->len, c_reset);
 629                 }
 630         }
 631 }
 632
 633 static void reuse_combine_diff(struct sline *sline, unsigned long cnt,
 634                                int i, int j)
 635 {
 636         /* We have already examined parent j and we know parent i
 637          * and parent j are the same, so reuse the combined result
 638          * of parent j for parent i.
 639          */
 640         unsigned long lno, imask, jmask;
 641         imask = (1UL<<i);
 642         jmask = (1UL<<j);
 643
 644         for (lno = 0; lno <= cnt; lno++) {
 645                 struct lline *ll = sline->lost_head;
 646                 sline->p_lno[i] = sline->p_lno[j];
 647                 while (ll) {
 648                         if (ll->parent_map & jmask)
 649                                 ll->parent_map |= imask;
 650                         ll = ll->next;
 651                 }
 652                 if (sline->flag & jmask)
 653                         sline->flag |= imask;
 654                 sline++;
 655         }
 656         /* the overall size of the file (sline[cnt]) */
 657         sline->p_lno[i] = sline->p_lno[j];
 658 }
 659
 660 static void dump_quoted_path(const char *head,
 661                              const char *prefix,
 662                              const char *path,
 663                              const char *c_meta, const char *c_reset)
 664 {
 665         static struct strbuf buf = STRBUF_INIT;
 666
 667         strbuf_reset(&buf);
 668         strbuf_addstr(&buf, c_meta);
 669         strbuf_addstr(&buf, head);
 670         quote_two_c_style(&buf, prefix, path, 0);
 671         strbuf_addstr(&buf, c_reset);
 672         puts(buf.buf);
 673 }
 674
 675 static void show_patch_diff(struct combine_diff_path *elem, int num_parent,
 676                             int dense, struct rev_info *rev)
 677 {
 678         struct diff_options *opt = &rev->diffopt;
 679         unsigned long result_size, cnt, lno;
 680         char *result, *cp;
 681         struct sline *sline; /* survived lines */
 682         int mode_differs = 0;
 683         int i, show_hunks;
 684         int working_tree_file = is_null_sha1(elem->sha1);
 685         int abbrev = DIFF_OPT_TST(opt, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
 686         const char *a_prefix, *b_prefix;
 687         mmfile_t result_file;
 688
 689         context = opt->context;
 690         a_prefix = opt->a_prefix ? opt->a_prefix : "a/";
 691         b_prefix = opt->b_prefix ? opt->b_prefix : "b/";
 692
 693         /* Read the result of merge first */
 694         if (!working_tree_file)
 695                 result = grab_blob(elem->sha1, &result_size);
 696         else {
 697                 /* Used by diff-tree to read from the working tree */
 698                 struct stat st;
 699                 int fd = -1;
 700
 701                 if (lstat(elem->path, &st) < 0)
 702                         goto deleted_file;
 703
 704                 if (S_ISLNK(st.st_mode)) {
 705                         struct strbuf buf = STRBUF_INIT;
 706
 707                         if (strbuf_readlink(&buf, elem->path, st.st_size) < 0) {
 708                                 error("readlink(%s): %s", elem->path,
 709                                       strerror(errno));
 710                                 return;
 711                         }
 712                         result_size = buf.len;
 713                         result = strbuf_detach(&buf, NULL);
 714                         elem->mode = canon_mode(st.st_mode);
 715                 }
 716                 else if (0 <= (fd = open(elem->path, O_RDONLY)) &&
 717                          !fstat(fd, &st)) {
 718                         size_t len = xsize_t(st.st_size);
 719                         ssize_t done;
 720                         int is_file, i;
 721
 722                         elem->mode = canon_mode(st.st_mode);
 723                         /* if symlinks don't work, assume symlink if all parents
 724                          * are symlinks
 725                          */
 726                         is_file = has_symlinks;
 727                         for (i = 0; !is_file && i < num_parent; i++)
 728                                 is_file = !S_ISLNK(elem->parent[i].mode);
 729                         if (!is_file)
 730                                 elem->mode = canon_mode(S_IFLNK);
 731
 732                         result_size = len;
 733                         result = xmalloc(len + 1);
 734
 735                         done = read_in_full(fd, result, len);
 736                         if (done < 0)
 737                                 die("read error '%s'", elem->path);
 738                         else if (done < len)
 739                                 die("early EOF '%s'", elem->path);
 740
 741                         result[len] = 0;
 742
 743                         /* If not a fake symlink, apply filters, e.g. autocrlf */
 744                         if (is_file) {
 745                                 struct strbuf buf = STRBUF_INIT;
 746
 747                                 if (convert_to_git(elem->path, result, len, &buf, safe_crlf)) {
 748                                         free(result);
 749                                         result = strbuf_detach(&buf, &len);
 750                                         result_size = len;
 751                                 }
 752                         }
 753                 }
 754                 else {
 755                 deleted_file:
 756                         result_size = 0;
 757                         elem->mode = 0;
 758                         result = xcalloc(1, 1);
 759                 }
 760
 761                 if (0 <= fd)
 762                         close(fd);
 763         }
 764
 765         for (cnt = 0, cp = result; cp < result + result_size; cp++) {
 766                 if (*cp == '\n')
 767                         cnt++;
 768         }
 769         if (result_size && result[result_size-1] != '\n')
 770                 cnt++; /* incomplete line */
 771
 772         sline = xcalloc(cnt+2, sizeof(*sline));
 773         sline[0].bol = result;
 774         for (lno = 0; lno <= cnt + 1; lno++) {
 775                 sline[lno].lost_tail = &sline[lno].lost_head;
 776                 sline[lno].flag = 0;
 777         }
 778         for (lno = 0, cp = result; cp < result + result_size; cp++) {
 779                 if (*cp == '\n') {
 780                         sline[lno].len = cp - sline[lno].bol;
 781                         lno++;
 782                         if (lno < cnt)
 783                                 sline[lno].bol = cp + 1;
 784                 }
 785         }
 786         if (result_size && result[result_size-1] != '\n')
 787                 sline[cnt-1].len = result_size - (sline[cnt-1].bol - result);
 788
 789         result_file.ptr = result;
 790         result_file.size = result_size;
 791
 792         /* Even p_lno[cnt+1] is valid -- that is for the end line number
 793          * for deletion hunk at the end.
 794          */
 795         sline[0].p_lno = xcalloc((cnt+2) * num_parent, sizeof(unsigned long));
 796         for (lno = 0; lno <= cnt; lno++)
 797                 sline[lno+1].p_lno = sline[lno].p_lno + num_parent;
 798
 799         for (i = 0; i < num_parent; i++) {
 800                 int j;
 801                 for (j = 0; j < i; j++) {
 802                         if (!hashcmp(elem->parent[i].sha1,
 803                                      elem->parent[j].sha1)) {
 804                                 reuse_combine_diff(sline, cnt, i, j);
 805                                 break;
 806                         }
 807                 }
 808                 if (i <= j)
 809                         combine_diff(elem->parent[i].sha1, &result_file, sline,
 810                                      cnt, i, num_parent);
 811                 if (elem->parent[i].mode != elem->mode)
 812                         mode_differs = 1;
 813         }
 814
 815         show_hunks = make_hunks(sline, cnt, num_parent, dense);
 816
 817         if (show_hunks || mode_differs || working_tree_file) {
 818                 const char *abb;
 819                 int use_color = DIFF_OPT_TST(opt, COLOR_DIFF);
 820                 const char *c_meta = diff_get_color(use_color, DIFF_METAINFO);
 821                 const char *c_reset = diff_get_color(use_color, DIFF_RESET);
 822                 int added = 0;
 823                 int deleted = 0;
 824
 825                 if (rev->loginfo && !rev->no_commit_id)
 826                         show_log(rev);
 827                 dump_quoted_path(dense ? "diff --cc " : "diff --combined ",
 828                                  "", elem->path, c_meta, c_reset);
 829                 printf("%sindex ", c_meta);
 830                 for (i = 0; i < num_parent; i++) {
 831                         abb = find_unique_abbrev(elem->parent[i].sha1,
 832                                                  abbrev);
 833                         printf("%s%s", i ? "," : "", abb);
 834                 }
 835                 abb = find_unique_abbrev(elem->sha1, abbrev);
 836                 printf("..%s%s\n", abb, c_reset);
 837
 838                 if (mode_differs) {
 839                         deleted = !elem->mode;
 840
 841                         /* We say it was added if nobody had it */
 842                         added = !deleted;
 843                         for (i = 0; added && i < num_parent; i++)
 844                                 if (elem->parent[i].status !=
 845                                     DIFF_STATUS_ADDED)
 846                                         added = 0;
 847                         if (added)
 848                                 printf("%snew file mode %06o",
 849                                        c_meta, elem->mode);
 850                         else {
 851                                 if (deleted)
 852                                         printf("%sdeleted file ", c_meta);
 853                                 printf("mode ");
 854                                 for (i = 0; i < num_parent; i++) {
 855                                         printf("%s%06o", i ? "," : "",
 856                                                elem->parent[i].mode);
 857                                 }
 858                                 if (elem->mode)
 859                                         printf("..%06o", elem->mode);
 860                         }
 861                         printf("%s\n", c_reset);
 862                 }
 863                 if (added)
 864                         dump_quoted_path("--- ", "", "/dev/null",
 865                                          c_meta, c_reset);
 866                 else
 867                         dump_quoted_path("--- ", a_prefix, elem->path,
 868                                          c_meta, c_reset);
 869                 if (deleted)
 870                         dump_quoted_path("+++ ", "", "/dev/null",
 871                                          c_meta, c_reset);
 872                 else
 873                         dump_quoted_path("+++ ", b_prefix, elem->path,
 874                                          c_meta, c_reset);
 875                 dump_sline(sline, cnt, num_parent,
 876                            DIFF_OPT_TST(opt, COLOR_DIFF));
 877         }
 878         free(result);
 879
 880         for (lno = 0; lno < cnt; lno++) {
 881                 if (sline[lno].lost_head) {
 882                         struct lline *ll = sline[lno].lost_head;
 883                         while (ll) {
 884                                 struct lline *tmp = ll;
 885                                 ll = ll->next;
 886                                 free(tmp);
 887                         }
 888                 }
 889         }
 890         free(sline[0].p_lno);
 891         free(sline);
 892 }
 893
 894 #define COLONS "::::::::::::::::::::::::::::::::"
 895
 896 static void show_raw_diff(struct combine_diff_path *p, int num_parent, struct rev_info *rev)
 897 {
 898         struct diff_options *opt = &rev->diffopt;
 899         int i, offset;
 900         const char *prefix;
 901         int line_termination, inter_name_termination;
 902
 903         line_termination = opt->line_termination;
 904         inter_name_termination = '\t';
 905         if (!line_termination)
 906                 inter_name_termination = 0;
 907
 908         if (rev->loginfo && !rev->no_commit_id)
 909                 show_log(rev);
 910
 911         if (opt->output_format & DIFF_FORMAT_RAW) {
 912                 offset = strlen(COLONS) - num_parent;
 913                 if (offset < 0)
 914                         offset = 0;
 915                 prefix = COLONS + offset;
 916
 917                 /* Show the modes */
 918                 for (i = 0; i < num_parent; i++) {
 919                         printf("%s%06o", prefix, p->parent[i].mode);
 920                         prefix = " ";
 921                 }
 922                 printf("%s%06o", prefix, p->mode);
 923
 924                 /* Show sha1's */
 925                 for (i = 0; i < num_parent; i++)
 926                         printf(" %s", diff_unique_abbrev(p->parent[i].sha1,
 927                                                          opt->abbrev));
 928                 printf(" %s ", diff_unique_abbrev(p->sha1, opt->abbrev));
 929         }
 930
 931         if (opt->output_format & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS)) {
 932                 for (i = 0; i < num_parent; i++)
 933                         putchar(p->parent[i].status);
 934                 putchar(inter_name_termination);
 935         }
 936
 937         write_name_quoted(p->path, stdout, line_termination);
 938 }
 939
 940 void show_combined_diff(struct combine_diff_path *p,
 941                        int num_parent,
 942                        int dense,
 943                        struct rev_info *rev)
 944 {
 945         struct diff_options *opt = &rev->diffopt;
 946         if (!p->len)
 947                 return;
 948         if (opt->output_format & (DIFF_FORMAT_RAW |
 949                                   DIFF_FORMAT_NAME |
 950                                   DIFF_FORMAT_NAME_STATUS))
 951                 show_raw_diff(p, num_parent, rev);
 952         else if (opt->output_format & DIFF_FORMAT_PATCH)
 953                 show_patch_diff(p, num_parent, dense, rev);
 954 }
 955
 956 void diff_tree_combined(const unsigned char *sha1,
 957                         const unsigned char parent[][20],
 958                         int num_parent,
 959                         int dense,
 960                         struct rev_info *rev)
 961 {
 962         struct diff_options *opt = &rev->diffopt;
 963         struct diff_options diffopts;
 964         struct combine_diff_path *p, *paths = NULL;
 965         int i, num_paths, needsep, show_log_first;
 966
 967         diffopts = *opt;
 968         diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
 969         DIFF_OPT_SET(&diffopts, RECURSIVE);
 970         DIFF_OPT_CLR(&diffopts, ALLOW_EXTERNAL);
 971
 972         show_log_first = !!rev->loginfo && !rev->no_commit_id;
 973         needsep = 0;
 974         /* find set of paths that everybody touches */
 975         for (i = 0; i < num_parent; i++) {
 976                 /* show stat against the first parent even
 977                  * when doing combined diff.
 978                  */
 979                 int stat_opt = (opt->output_format &
 980                                 (DIFF_FORMAT_NUMSTAT|DIFF_FORMAT_DIFFSTAT));
 981                 if (i == 0 && stat_opt)
 982                         diffopts.output_format = stat_opt;
 983                 else
 984                         diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
 985                 diff_tree_sha1(parent[i], sha1, "", &diffopts);
 986                 diffcore_std(&diffopts);
 987                 paths = intersect_paths(paths, i, num_parent);
 988
 989                 if (show_log_first && i == 0) {
 990                         show_log(rev);
 991                         if (rev->verbose_header && opt->output_format)
 992                                 putchar(opt->line_termination);
 993                 }
 994                 diff_flush(&diffopts);
 995         }
 996
 997         /* find out surviving paths */
 998         for (num_paths = 0, p = paths; p; p = p->next) {
 999                 if (p->len)
1000                         num_paths++;
1001         }
1002         if (num_paths) {
1003                 if (opt->output_format & (DIFF_FORMAT_RAW |
1004                                           DIFF_FORMAT_NAME |
1005                                           DIFF_FORMAT_NAME_STATUS)) {
1006                         for (p = paths; p; p = p->next) {
1007                                 if (p->len)
1008                                         show_raw_diff(p, num_parent, rev);
1009                         }
1010                         needsep = 1;
1011                 }
1012                 else if (opt->output_format &
1013                          (DIFF_FORMAT_NUMSTAT|DIFF_FORMAT_DIFFSTAT))
1014                         needsep = 1;
1015                 if (opt->output_format & DIFF_FORMAT_PATCH) {
1016                         if (needsep)
1017                                 putchar(opt->line_termination);
1018                         for (p = paths; p; p = p->next) {
1019                                 if (p->len)
1020                                         show_patch_diff(p, num_parent, dense,
1021                                                         rev);
1022                         }
1023                 }
1024         }
1025
1026         /* Clean things up */
1027         while (paths) {
1028                 struct combine_diff_path *tmp = paths;
1029                 paths = paths->next;
1030                 free(tmp);
1031         }
1032 }
1033
1034 void diff_tree_combined_merge(const unsigned char *sha1,
1035                              int dense, struct rev_info *rev)
1036 {
1037         int num_parent;
1038         const unsigned char (*parent)[20];
1039         struct commit *commit = lookup_commit(sha1);
1040         struct commit_list *parents;
1041
1042         /* count parents */
1043         for (parents = commit->parents, num_parent = 0;
1044              parents;
1045              parents = parents->next, num_parent++)
1046                 ; /* nothing */
1047
1048         parent = xmalloc(num_parent * sizeof(*parent));
1049         for (parents = commit->parents, num_parent = 0;
1050              parents;
1051              parents = parents->next, num_parent++)
1052                 hashcpy((unsigned char*)(parent + num_parent),
1053                         parents->item->object.sha1);
1054         diff_tree_combined(sha1, parent, num_parent, dense, rev);
1055 }