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 #include "refs.h"
  10
  11 static struct combine_diff_path *intersect_paths(struct combine_diff_path *curr, int n, int num_parent)
  12 {
  13         struct diff_queue_struct *q = &diff_queued_diff;
  14         struct combine_diff_path *p;
  15         int i;
  16
  17         if (!n) {
  18                 struct combine_diff_path *list = NULL, **tail = &list;
  19                 for (i = 0; i < q->nr; i++) {
  20                         int len;
  21                         const char *path;
  22                         if (diff_unmodified_pair(q->queue[i]))
  23                                 continue;
  24                         path = q->queue[i]->two->path;
  25                         len = strlen(path);
  26                         p = xmalloc(combine_diff_path_size(num_parent, len));
  27                         p->path = (char *) &(p->parent[num_parent]);
  28                         memcpy(p->path, path, len);
  29                         p->path[len] = 0;
  30                         p->len = len;
  31                         p->next = NULL;
  32                         memset(p->parent, 0,
  33                                sizeof(p->parent[0]) * num_parent);
  34
  35                         hashcpy(p->sha1, q->queue[i]->two->sha1);
  36                         p->mode = q->queue[i]->two->mode;
  37                         hashcpy(p->parent[n].sha1, q->queue[i]->one->sha1);
  38                         p->parent[n].mode = q->queue[i]->one->mode;
  39                         p->parent[n].status = q->queue[i]->status;
  40                         *tail = p;
  41                         tail = &p->next;
  42                 }
  43                 return list;
  44         }
  45
  46         for (p = curr; p; p = p->next) {
  47                 int found = 0;
  48                 if (!p->len)
  49                         continue;
  50                 for (i = 0; i < q->nr; i++) {
  51                         const char *path;
  52                         int len;
  53
  54                         if (diff_unmodified_pair(q->queue[i]))
  55                                 continue;
  56                         path = q->queue[i]->two->path;
  57                         len = strlen(path);
  58                         if (len == p->len && !memcmp(path, p->path, len)) {
  59                                 found = 1;
  60                                 hashcpy(p->parent[n].sha1, q->queue[i]->one->sha1);
  61                                 p->parent[n].mode = q->queue[i]->one->mode;
  62                                 p->parent[n].status = q->queue[i]->status;
  63                                 break;
  64                         }
  65                 }
  66                 if (!found)
  67                         p->len = 0;
  68         }
  69         return curr;
  70 }
  71
  72 /* Lines lost from parent */
  73 struct lline {
  74         struct lline *next;
  75         int len;
  76         unsigned long parent_map;
  77         char line[FLEX_ARRAY];
  78 };
  79
  80 /* Lines surviving in the merge result */
  81 struct sline {
  82         struct lline *lost_head, **lost_tail;
  83         char *bol;
  84         int len;
  85         /* bit 0 up to (N-1) are on if the parent has this line (i.e.
  86          * we did not change it).
  87          * bit N is used for "interesting" lines, including context.
  88          * bit (N+1) is used for "do not show deletion before this".
  89          */
  90         unsigned long flag;
  91         unsigned long *p_lno;
  92 };
  93
  94 static char *grab_blob(const unsigned char *sha1, unsigned int mode, unsigned long *size)
  95 {
  96         char *blob;
  97         enum object_type type;
  98
  99         if (S_ISGITLINK(mode)) {
 100                 blob = xmalloc(100);
 101                 *size = snprintf(blob, 100,
 102                                  "Subproject commit %s\n", sha1_to_hex(sha1));
 103         } else if (is_null_sha1(sha1)) {
 104                 /* deleted blob */
 105                 *size = 0;
 106                 return xcalloc(1, 1);
 107         } else {
 108                 blob = read_sha1_file(sha1, &type, size);
 109                 if (type != OBJ_BLOB)
 110                         die("object '%s' is not a blob!", sha1_to_hex(sha1));
 111         }
 112         return blob;
 113 }
 114
 115 static void append_lost(struct sline *sline, int n, const char *line, int len)
 116 {
 117         struct lline *lline;
 118         unsigned long this_mask = (1UL<<n);
 119         if (line[len-1] == '\n')
 120                 len--;
 121
 122         /* Check to see if we can squash things */
 123         if (sline->lost_head) {
 124                 struct lline *last_one = NULL;
 125                 /* We cannot squash it with earlier one */
 126                 for (lline = sline->lost_head;
 127                      lline;
 128                      lline = lline->next)
 129                         if (lline->parent_map & this_mask)
 130                                 last_one = lline;
 131                 lline = last_one ? last_one->next : sline->lost_head;
 132                 while (lline) {
 133                         if (lline->len == len &&
 134                             !memcmp(lline->line, line, len)) {
 135                                 lline->parent_map |= this_mask;
 136                                 return;
 137                         }
 138                         lline = lline->next;
 139                 }
 140         }
 141
 142         lline = xmalloc(sizeof(*lline) + len + 1);
 143         lline->len = len;
 144         lline->next = NULL;
 145         lline->parent_map = this_mask;
 146         memcpy(lline->line, line, len);
 147         lline->line[len] = 0;
 148         *sline->lost_tail = lline;
 149         sline->lost_tail = &lline->next;
 150 }
 151
 152 struct combine_diff_state {
 153         unsigned int lno;
 154         int ob, on, nb, nn;
 155         unsigned long nmask;
 156         int num_parent;
 157         int n;
 158         struct sline *sline;
 159         struct sline *lost_bucket;
 160 };
 161
 162 static void consume_line(void *state_, char *line, unsigned long len)
 163 {
 164         struct combine_diff_state *state = state_;
 165         if (5 < len && !memcmp("@@ -", line, 4)) {
 166                 if (parse_hunk_header(line, len,
 167                                       &state->ob, &state->on,
 168                                       &state->nb, &state->nn))
 169                         return;
 170                 state->lno = state->nb;
 171                 if (!state->nb)
 172                         /* @@ -1,2 +0,0 @@ to remove the
 173                          * first two lines...
 174                          */
 175                         state->nb = 1;
 176                 if (state->nn == 0)
 177                         /* @@ -X,Y +N,0 @@ removed Y lines
 178                          * that would have come *after* line N
 179                          * in the result.  Our lost buckets hang
 180                          * to the line after the removed lines,
 181                          */
 182                         state->lost_bucket = &state->sline[state->nb];
 183                 else
 184                         state->lost_bucket = &state->sline[state->nb-1];
 185                 if (!state->sline[state->nb-1].p_lno)
 186                         state->sline[state->nb-1].p_lno =
 187                                 xcalloc(state->num_parent,
 188                                         sizeof(unsigned long));
 189                 state->sline[state->nb-1].p_lno[state->n] = state->ob;
 190                 return;
 191         }
 192         if (!state->lost_bucket)
 193                 return; /* not in any hunk yet */
 194         switch (line[0]) {
 195         case '-':
 196                 append_lost(state->lost_bucket, state->n, line+1, len-1);
 197                 break;
 198         case '+':
 199                 state->sline[state->lno-1].flag |= state->nmask;
 200                 state->lno++;
 201                 break;
 202         }
 203 }
 204
 205 static void combine_diff(const unsigned char *parent, unsigned int mode,
 206                          mmfile_t *result_file,
 207                          struct sline *sline, unsigned int cnt, int n,
 208                          int num_parent)
 209 {
 210         unsigned int p_lno, lno;
 211         unsigned long nmask = (1UL << n);
 212         xpparam_t xpp;
 213         xdemitconf_t xecfg;
 214         mmfile_t parent_file;
 215         xdemitcb_t ecb;
 216         struct combine_diff_state state;
 217         unsigned long sz;
 218
 219         if (!cnt)
 220                 return; /* result deleted */
 221
 222         parent_file.ptr = grab_blob(parent, mode, &sz);
 223         parent_file.size = sz;
 224         memset(&xpp, 0, sizeof(xpp));
 225         xpp.flags = XDF_NEED_MINIMAL;
 226         memset(&xecfg, 0, sizeof(xecfg));
 227         memset(&state, 0, sizeof(state));
 228         state.nmask = nmask;
 229         state.sline = sline;
 230         state.lno = 1;
 231         state.num_parent = num_parent;
 232         state.n = n;
 233
 234         xdi_diff_outf(&parent_file, result_file, consume_line, &state,
 235                       &xpp, &xecfg, &ecb);
 236         free(parent_file.ptr);
 237
 238         /* Assign line numbers for this parent.
 239          *
 240          * sline[lno].p_lno[n] records the first line number
 241          * (counting from 1) for parent N if the final hunk display
 242          * started by showing sline[lno] (possibly showing the lost
 243          * lines attached to it first).
 244          */
 245         for (lno = 0,  p_lno = 1; lno <= cnt; lno++) {
 246                 struct lline *ll;
 247                 sline[lno].p_lno[n] = p_lno;
 248
 249                 /* How many lines would this sline advance the p_lno? */
 250                 ll = sline[lno].lost_head;
 251                 while (ll) {
 252                         if (ll->parent_map & nmask)
 253                                 p_lno++; /* '-' means parent had it */
 254                         ll = ll->next;
 255                 }
 256                 if (lno < cnt && !(sline[lno].flag & nmask))
 257                         p_lno++; /* no '+' means parent had it */
 258         }
 259         sline[lno].p_lno[n] = p_lno; /* trailer */
 260 }
 261
 262 static unsigned long context = 3;
 263 static char combine_marker = '@';
 264
 265 static int interesting(struct sline *sline, unsigned long all_mask)
 266 {
 267         /* If some parents lost lines here, or if we have added to
 268          * some parent, it is interesting.
 269          */
 270         return ((sline->flag & all_mask) || sline->lost_head);
 271 }
 272
 273 static unsigned long adjust_hunk_tail(struct sline *sline,
 274                                       unsigned long all_mask,
 275                                       unsigned long hunk_begin,
 276                                       unsigned long i)
 277 {
 278         /* i points at the first uninteresting line.  If the last line
 279          * of the hunk was interesting only because it has some
 280          * deletion, then it is not all that interesting for the
 281          * purpose of giving trailing context lines.  This is because
 282          * we output '-' line and then unmodified sline[i-1] itself in
 283          * that case which gives us one extra context line.
 284          */
 285         if ((hunk_begin + 1 <= i) && !(sline[i-1].flag & all_mask))
 286                 i--;
 287         return i;
 288 }
 289
 290 static unsigned long find_next(struct sline *sline,
 291                                unsigned long mark,
 292                                unsigned long i,
 293                                unsigned long cnt,
 294                                int look_for_uninteresting)
 295 {
 296         /* We have examined up to i-1 and are about to look at i.
 297          * Find next interesting or uninteresting line.  Here,
 298          * "interesting" does not mean interesting(), but marked by
 299          * the give_context() function below (i.e. it includes context
 300          * lines that are not interesting to interesting() function
 301          * that are surrounded by interesting() ones.
 302          */
 303         while (i <= cnt)
 304                 if (look_for_uninteresting
 305                     ? !(sline[i].flag & mark)
 306                     : (sline[i].flag & mark))
 307                         return i;
 308                 else
 309                         i++;
 310         return i;
 311 }
 312
 313 static int give_context(struct sline *sline, unsigned long cnt, int num_parent)
 314 {
 315         unsigned long all_mask = (1UL<<num_parent) - 1;
 316         unsigned long mark = (1UL<<num_parent);
 317         unsigned long no_pre_delete = (2UL<<num_parent);
 318         unsigned long i;
 319
 320         /* Two groups of interesting lines may have a short gap of
 321          * uninteresting lines.  Connect such groups to give them a
 322          * bit of context.
 323          *
 324          * We first start from what the interesting() function says,
 325          * and mark them with "mark", and paint context lines with the
 326          * mark.  So interesting() would still say false for such context
 327          * lines but they are treated as "interesting" in the end.
 328          */
 329         i = find_next(sline, mark, 0, cnt, 0);
 330         if (cnt < i)
 331                 return 0;
 332
 333         while (i <= cnt) {
 334                 unsigned long j = (context < i) ? (i - context) : 0;
 335                 unsigned long k;
 336
 337                 /* Paint a few lines before the first interesting line. */
 338                 while (j < i)
 339                         sline[j++].flag |= mark | no_pre_delete;
 340
 341         again:
 342                 /* we know up to i is to be included.  where does the
 343                  * next uninteresting one start?
 344                  */
 345                 j = find_next(sline, mark, i, cnt, 1);
 346                 if (cnt < j)
 347                         break; /* the rest are all interesting */
 348
 349                 /* lookahead context lines */
 350                 k = find_next(sline, mark, j, cnt, 0);
 351                 j = adjust_hunk_tail(sline, all_mask, i, j);
 352
 353                 if (k < j + context) {
 354                         /* k is interesting and [j,k) are not, but
 355                          * paint them interesting because the gap is small.
 356                          */
 357                         while (j < k)
 358                                 sline[j++].flag |= mark;
 359                         i = k;
 360                         goto again;
 361                 }
 362
 363                 /* j is the first uninteresting line and there is
 364                  * no overlap beyond it within context lines.  Paint
 365                  * the trailing edge a bit.
 366                  */
 367                 i = k;
 368                 k = (j + context < cnt+1) ? j + context : cnt+1;
 369                 while (j < k)
 370                         sline[j++].flag |= mark;
 371         }
 372         return 1;
 373 }
 374
 375 static int make_hunks(struct sline *sline, unsigned long cnt,
 376                        int num_parent, int dense)
 377 {
 378         unsigned long all_mask = (1UL<<num_parent) - 1;
 379         unsigned long mark = (1UL<<num_parent);
 380         unsigned long i;
 381         int has_interesting = 0;
 382
 383         for (i = 0; i <= cnt; i++) {
 384                 if (interesting(&sline[i], all_mask))
 385                         sline[i].flag |= mark;
 386                 else
 387                         sline[i].flag &= ~mark;
 388         }
 389         if (!dense)
 390                 return give_context(sline, cnt, num_parent);
 391
 392         /* Look at each hunk, and if we have changes from only one
 393          * parent, or the changes are the same from all but one
 394          * parent, mark that uninteresting.
 395          */
 396         i = 0;
 397         while (i <= cnt) {
 398                 unsigned long j, hunk_begin, hunk_end;
 399                 unsigned long same_diff;
 400                 while (i <= cnt && !(sline[i].flag & mark))
 401                         i++;
 402                 if (cnt < i)
 403                         break; /* No more interesting hunks */
 404                 hunk_begin = i;
 405                 for (j = i + 1; j <= cnt; j++) {
 406                         if (!(sline[j].flag & mark)) {
 407                                 /* Look beyond the end to see if there
 408                                  * is an interesting line after this
 409                                  * hunk within context span.
 410                                  */
 411                                 unsigned long la; /* lookahead */
 412                                 int contin = 0;
 413                                 la = adjust_hunk_tail(sline, all_mask,
 414                                                      hunk_begin, j);
 415                                 la = (la + context < cnt + 1) ?
 416                                         (la + context) : cnt + 1;
 417                                 while (j <= --la) {
 418                                         if (sline[la].flag & mark) {
 419                                                 contin = 1;
 420                                                 break;
 421                                         }
 422                                 }
 423                                 if (!contin)
 424                                         break;
 425                                 j = la;
 426                         }
 427                 }
 428                 hunk_end = j;
 429
 430                 /* [i..hunk_end) are interesting.  Now is it really
 431                  * interesting?  We check if there are only two versions
 432                  * and the result matches one of them.  That is, we look
 433                  * at:
 434                  *   (+) line, which records lines added to which parents;
 435                  *       this line appears in the result.
 436                  *   (-) line, which records from what parents the line
 437                  *       was removed; this line does not appear in the result.
 438                  * then check the set of parents the result has difference
 439                  * from, from all lines.  If there are lines that has
 440                  * different set of parents that the result has differences
 441                  * from, that means we have more than two versions.
 442                  *
 443                  * Even when we have only two versions, if the result does
 444                  * not match any of the parents, the it should be considered
 445                  * interesting.  In such a case, we would have all '+' line.
 446                  * After passing the above "two versions" test, that would
 447                  * appear as "the same set of parents" to be "all parents".
 448                  */
 449                 same_diff = 0;
 450                 has_interesting = 0;
 451                 for (j = i; j < hunk_end && !has_interesting; j++) {
 452                         unsigned long this_diff = sline[j].flag & all_mask;
 453                         struct lline *ll = sline[j].lost_head;
 454                         if (this_diff) {
 455                                 /* This has some changes.  Is it the
 456                                  * same as others?
 457                                  */
 458                                 if (!same_diff)
 459                                         same_diff = this_diff;
 460                                 else if (same_diff != this_diff) {
 461                                         has_interesting = 1;
 462                                         break;
 463                                 }
 464                         }
 465                         while (ll && !has_interesting) {
 466                                 /* Lost this line from these parents;
 467                                  * who are they?  Are they the same?
 468                                  */
 469                                 this_diff = ll->parent_map;
 470                                 if (!same_diff)
 471                                         same_diff = this_diff;
 472                                 else if (same_diff != this_diff) {
 473                                         has_interesting = 1;
 474                                 }
 475                                 ll = ll->next;
 476                         }
 477                 }
 478
 479                 if (!has_interesting && same_diff != all_mask) {
 480                         /* This hunk is not that interesting after all */
 481                         for (j = hunk_begin; j < hunk_end; j++)
 482                                 sline[j].flag &= ~mark;
 483                 }
 484                 i = hunk_end;
 485         }
 486
 487         has_interesting = give_context(sline, cnt, num_parent);
 488         return has_interesting;
 489 }
 490
 491 static void show_parent_lno(struct sline *sline, unsigned long l0, unsigned long l1, int n, unsigned long null_context)
 492 {
 493         l0 = sline[l0].p_lno[n];
 494         l1 = sline[l1].p_lno[n];
 495         printf(" -%lu,%lu", l0, l1-l0-null_context);
 496 }
 497
 498 static int hunk_comment_line(const char *bol)
 499 {
 500         int ch;
 501
 502         if (!bol)
 503                 return 0;
 504         ch = *bol & 0xff;
 505         return (isalpha(ch) || ch == '_' || ch == '$');
 506 }
 507
 508 static void show_line_to_eol(const char *line, int len, const char *reset)
 509 {
 510         int saw_cr_at_eol = 0;
 511         if (len < 0)
 512                 len = strlen(line);
 513         saw_cr_at_eol = (len && line[len-1] == '\r');
 514
 515         printf("%.*s%s%s\n", len - saw_cr_at_eol, line,
 516                reset,
 517                saw_cr_at_eol ? "\r" : "");
 518 }
 519
 520 static void dump_sline(struct sline *sline, unsigned long cnt, int num_parent,
 521                        int use_color)
 522 {
 523         unsigned long mark = (1UL<<num_parent);
 524         unsigned long no_pre_delete = (2UL<<num_parent);
 525         int i;
 526         unsigned long lno = 0;
 527         const char *c_frag = diff_get_color(use_color, DIFF_FRAGINFO);
 528         const char *c_new = diff_get_color(use_color, DIFF_FILE_NEW);
 529         const char *c_old = diff_get_color(use_color, DIFF_FILE_OLD);
 530         const char *c_plain = diff_get_color(use_color, DIFF_PLAIN);
 531         const char *c_reset = diff_get_color(use_color, DIFF_RESET);
 532
 533         if (!cnt)
 534                 return; /* result deleted */
 535
 536         while (1) {
 537                 unsigned long hunk_end;
 538                 unsigned long rlines;
 539                 const char *hunk_comment = NULL;
 540                 unsigned long null_context = 0;
 541
 542                 while (lno <= cnt && !(sline[lno].flag & mark)) {
 543                         if (hunk_comment_line(sline[lno].bol))
 544                                 hunk_comment = sline[lno].bol;
 545                         lno++;
 546                 }
 547                 if (cnt < lno)
 548                         break;
 549                 else {
 550                         for (hunk_end = lno + 1; hunk_end <= cnt; hunk_end++)
 551                                 if (!(sline[hunk_end].flag & mark))
 552                                         break;
 553                 }
 554                 rlines = hunk_end - lno;
 555                 if (cnt < hunk_end)
 556                         rlines--; /* pointing at the last delete hunk */
 557
 558                 if (!context) {
 559                         /*
 560                          * Even when running with --unified=0, all
 561                          * lines in the hunk needs to be processed in
 562                          * the loop below in order to show the
 563                          * deletion recorded in lost_head.  However,
 564                          * we do not want to show the resulting line
 565                          * with all blank context markers in such a
 566                          * case.  Compensate.
 567                          */
 568                         unsigned long j;
 569                         for (j = lno; j < hunk_end; j++)
 570                                 if (!(sline[j].flag & (mark-1)))
 571                                         null_context++;
 572                         rlines -= null_context;
 573                 }
 574
 575                 fputs(c_frag, stdout);
 576                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 577                 for (i = 0; i < num_parent; i++)
 578                         show_parent_lno(sline, lno, hunk_end, i, null_context);
 579                 printf(" +%lu,%lu ", lno+1, rlines);
 580                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 581
 582                 if (hunk_comment) {
 583                         int comment_end = 0;
 584                         for (i = 0; i < 40; i++) {
 585                                 int ch = hunk_comment[i] & 0xff;
 586                                 if (!ch || ch == '\n')
 587                                         break;
 588                                 if (!isspace(ch))
 589                                     comment_end = i;
 590                         }
 591                         if (comment_end)
 592                                 putchar(' ');
 593                         for (i = 0; i < comment_end; i++)
 594                                 putchar(hunk_comment[i]);
 595                 }
 596
 597                 printf("%s\n", c_reset);
 598                 while (lno < hunk_end) {
 599                         struct lline *ll;
 600                         int j;
 601                         unsigned long p_mask;
 602                         struct sline *sl = &sline[lno++];
 603                         ll = (sl->flag & no_pre_delete) ? NULL : sl->lost_head;
 604                         while (ll) {
 605                                 fputs(c_old, stdout);
 606                                 for (j = 0; j < num_parent; j++) {
 607                                         if (ll->parent_map & (1UL<<j))
 608                                                 putchar('-');
 609                                         else
 610                                                 putchar(' ');
 611                                 }
 612                                 show_line_to_eol(ll->line, -1, c_reset);
 613                                 ll = ll->next;
 614                         }
 615                         if (cnt < lno)
 616                                 break;
 617                         p_mask = 1;
 618                         if (!(sl->flag & (mark-1))) {
 619                                 /*
 620                                  * This sline was here to hang the
 621                                  * lost lines in front of it.
 622                                  */
 623                                 if (!context)
 624                                         continue;
 625                                 fputs(c_plain, stdout);
 626                         }
 627                         else
 628                                 fputs(c_new, stdout);
 629                         for (j = 0; j < num_parent; j++) {
 630                                 if (p_mask & sl->flag)
 631                                         putchar('+');
 632                                 else
 633                                         putchar(' ');
 634                                 p_mask <<= 1;
 635                         }
 636                         show_line_to_eol(sl->bol, sl->len, c_reset);
 637                 }
 638         }
 639 }
 640
 641 static void reuse_combine_diff(struct sline *sline, unsigned long cnt,
 642                                int i, int j)
 643 {
 644         /* We have already examined parent j and we know parent i
 645          * and parent j are the same, so reuse the combined result
 646          * of parent j for parent i.
 647          */
 648         unsigned long lno, imask, jmask;
 649         imask = (1UL<<i);
 650         jmask = (1UL<<j);
 651
 652         for (lno = 0; lno <= cnt; lno++) {
 653                 struct lline *ll = sline->lost_head;
 654                 sline->p_lno[i] = sline->p_lno[j];
 655                 while (ll) {
 656                         if (ll->parent_map & jmask)
 657                                 ll->parent_map |= imask;
 658                         ll = ll->next;
 659                 }
 660                 if (sline->flag & jmask)
 661                         sline->flag |= imask;
 662                 sline++;
 663         }
 664         /* the overall size of the file (sline[cnt]) */
 665         sline->p_lno[i] = sline->p_lno[j];
 666 }
 667
 668 static void dump_quoted_path(const char *head,
 669                              const char *prefix,
 670                              const char *path,
 671                              const char *c_meta, const char *c_reset)
 672 {
 673         static struct strbuf buf = STRBUF_INIT;
 674
 675         strbuf_reset(&buf);
 676         strbuf_addstr(&buf, c_meta);
 677         strbuf_addstr(&buf, head);
 678         quote_two_c_style(&buf, prefix, path, 0);
 679         strbuf_addstr(&buf, c_reset);
 680         puts(buf.buf);
 681 }
 682
 683 static void show_patch_diff(struct combine_diff_path *elem, int num_parent,
 684                             int dense, struct rev_info *rev)
 685 {
 686         struct diff_options *opt = &rev->diffopt;
 687         unsigned long result_size, cnt, lno;
 688         char *result, *cp;
 689         struct sline *sline; /* survived lines */
 690         int mode_differs = 0;
 691         int i, show_hunks;
 692         int working_tree_file = is_null_sha1(elem->sha1);
 693         int abbrev = DIFF_OPT_TST(opt, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
 694         const char *a_prefix, *b_prefix;
 695         mmfile_t result_file;
 696
 697         context = opt->context;
 698         a_prefix = opt->a_prefix ? opt->a_prefix : "a/";
 699         b_prefix = opt->b_prefix ? opt->b_prefix : "b/";
 700
 701         /* Read the result of merge first */
 702         if (!working_tree_file)
 703                 result = grab_blob(elem->sha1, elem->mode, &result_size);
 704         else {
 705                 /* Used by diff-tree to read from the working tree */
 706                 struct stat st;
 707                 int fd = -1;
 708
 709                 if (lstat(elem->path, &st) < 0)
 710                         goto deleted_file;
 711
 712                 if (S_ISLNK(st.st_mode)) {
 713                         struct strbuf buf = STRBUF_INIT;
 714
 715                         if (strbuf_readlink(&buf, elem->path, st.st_size) < 0) {
 716                                 error("readlink(%s): %s", elem->path,
 717                                       strerror(errno));
 718                                 return;
 719                         }
 720                         result_size = buf.len;
 721                         result = strbuf_detach(&buf, NULL);
 722                         elem->mode = canon_mode(st.st_mode);
 723                 } else if (S_ISDIR(st.st_mode)) {
 724                         unsigned char sha1[20];
 725                         if (resolve_gitlink_ref(elem->path, "HEAD", sha1) < 0)
 726                                 result = grab_blob(elem->sha1, elem->mode, &result_size);
 727                         else
 728                                 result = grab_blob(sha1, elem->mode, &result_size);
 729                 } else if (0 <= (fd = open(elem->path, O_RDONLY))) {
 730                         size_t len = xsize_t(st.st_size);
 731                         ssize_t done;
 732                         int is_file, i;
 733
 734                         elem->mode = canon_mode(st.st_mode);
 735                         /* if symlinks don't work, assume symlink if all parents
 736                          * are symlinks
 737                          */
 738                         is_file = has_symlinks;
 739                         for (i = 0; !is_file && i < num_parent; i++)
 740                                 is_file = !S_ISLNK(elem->parent[i].mode);
 741                         if (!is_file)
 742                                 elem->mode = canon_mode(S_IFLNK);
 743
 744                         result_size = len;
 745                         result = xmalloc(len + 1);
 746
 747                         done = read_in_full(fd, result, len);
 748                         if (done < 0)
 749                                 die("read error '%s'", elem->path);
 750                         else if (done < len)
 751                                 die("early EOF '%s'", elem->path);
 752
 753                         result[len] = 0;
 754
 755                         /* If not a fake symlink, apply filters, e.g. autocrlf */
 756                         if (is_file) {
 757                                 struct strbuf buf = STRBUF_INIT;
 758
 759                                 if (convert_to_git(elem->path, result, len, &buf, safe_crlf)) {
 760                                         free(result);
 761                                         result = strbuf_detach(&buf, &len);
 762                                         result_size = len;
 763                                 }
 764                         }
 765                 }
 766                 else {
 767                 deleted_file:
 768                         result_size = 0;
 769                         elem->mode = 0;
 770                         result = xcalloc(1, 1);
 771                 }
 772
 773                 if (0 <= fd)
 774                         close(fd);
 775         }
 776
 777         for (cnt = 0, cp = result; cp < result + result_size; cp++) {
 778                 if (*cp == '\n')
 779                         cnt++;
 780         }
 781         if (result_size && result[result_size-1] != '\n')
 782                 cnt++; /* incomplete line */
 783
 784         sline = xcalloc(cnt+2, sizeof(*sline));
 785         sline[0].bol = result;
 786         for (lno = 0; lno <= cnt + 1; lno++) {
 787                 sline[lno].lost_tail = &sline[lno].lost_head;
 788                 sline[lno].flag = 0;
 789         }
 790         for (lno = 0, cp = result; cp < result + result_size; cp++) {
 791                 if (*cp == '\n') {
 792                         sline[lno].len = cp - sline[lno].bol;
 793                         lno++;
 794                         if (lno < cnt)
 795                                 sline[lno].bol = cp + 1;
 796                 }
 797         }
 798         if (result_size && result[result_size-1] != '\n')
 799                 sline[cnt-1].len = result_size - (sline[cnt-1].bol - result);
 800
 801         result_file.ptr = result;
 802         result_file.size = result_size;
 803
 804         /* Even p_lno[cnt+1] is valid -- that is for the end line number
 805          * for deletion hunk at the end.
 806          */
 807         sline[0].p_lno = xcalloc((cnt+2) * num_parent, sizeof(unsigned long));
 808         for (lno = 0; lno <= cnt; lno++)
 809                 sline[lno+1].p_lno = sline[lno].p_lno + num_parent;
 810
 811         for (i = 0; i < num_parent; i++) {
 812                 int j;
 813                 for (j = 0; j < i; j++) {
 814                         if (!hashcmp(elem->parent[i].sha1,
 815                                      elem->parent[j].sha1)) {
 816                                 reuse_combine_diff(sline, cnt, i, j);
 817                                 break;
 818                         }
 819                 }
 820                 if (i <= j)
 821                         combine_diff(elem->parent[i].sha1,
 822                                      elem->parent[i].mode,
 823                                      &result_file, sline,
 824                                      cnt, i, num_parent);
 825                 if (elem->parent[i].mode != elem->mode)
 826                         mode_differs = 1;
 827         }
 828
 829         show_hunks = make_hunks(sline, cnt, num_parent, dense);
 830
 831         if (show_hunks || mode_differs || working_tree_file) {
 832                 const char *abb;
 833                 int use_color = DIFF_OPT_TST(opt, COLOR_DIFF);
 834                 const char *c_meta = diff_get_color(use_color, DIFF_METAINFO);
 835                 const char *c_reset = diff_get_color(use_color, DIFF_RESET);
 836                 int added = 0;
 837                 int deleted = 0;
 838
 839                 if (rev->loginfo && !rev->no_commit_id)
 840                         show_log(rev);
 841                 dump_quoted_path(dense ? "diff --cc " : "diff --combined ",
 842                                  "", elem->path, c_meta, c_reset);
 843                 printf("%sindex ", c_meta);
 844                 for (i = 0; i < num_parent; i++) {
 845                         abb = find_unique_abbrev(elem->parent[i].sha1,
 846                                                  abbrev);
 847                         printf("%s%s", i ? "," : "", abb);
 848                 }
 849                 abb = find_unique_abbrev(elem->sha1, abbrev);
 850                 printf("..%s%s\n", abb, c_reset);
 851
 852                 if (mode_differs) {
 853                         deleted = !elem->mode;
 854
 855                         /* We say it was added if nobody had it */
 856                         added = !deleted;
 857                         for (i = 0; added && i < num_parent; i++)
 858                                 if (elem->parent[i].status !=
 859                                     DIFF_STATUS_ADDED)
 860                                         added = 0;
 861                         if (added)
 862                                 printf("%snew file mode %06o",
 863                                        c_meta, elem->mode);
 864                         else {
 865                                 if (deleted)
 866                                         printf("%sdeleted file ", c_meta);
 867                                 printf("mode ");
 868                                 for (i = 0; i < num_parent; i++) {
 869                                         printf("%s%06o", i ? "," : "",
 870                                                elem->parent[i].mode);
 871                                 }
 872                                 if (elem->mode)
 873                                         printf("..%06o", elem->mode);
 874                         }
 875                         printf("%s\n", c_reset);
 876                 }
 877                 if (added)
 878                         dump_quoted_path("--- ", "", "/dev/null",
 879                                          c_meta, c_reset);
 880                 else
 881                         dump_quoted_path("--- ", a_prefix, elem->path,
 882                                          c_meta, c_reset);
 883                 if (deleted)
 884                         dump_quoted_path("+++ ", "", "/dev/null",
 885                                          c_meta, c_reset);
 886                 else
 887                         dump_quoted_path("+++ ", b_prefix, elem->path,
 888                                          c_meta, c_reset);
 889                 dump_sline(sline, cnt, num_parent,
 890                            DIFF_OPT_TST(opt, COLOR_DIFF));
 891         }
 892         free(result);
 893
 894         for (lno = 0; lno < cnt; lno++) {
 895                 if (sline[lno].lost_head) {
 896                         struct lline *ll = sline[lno].lost_head;
 897                         while (ll) {
 898                                 struct lline *tmp = ll;
 899                                 ll = ll->next;
 900                                 free(tmp);
 901                         }
 902                 }
 903         }
 904         free(sline[0].p_lno);
 905         free(sline);
 906 }
 907
 908 #define COLONS "::::::::::::::::::::::::::::::::"
 909
 910 static void show_raw_diff(struct combine_diff_path *p, int num_parent, struct rev_info *rev)
 911 {
 912         struct diff_options *opt = &rev->diffopt;
 913         int i, offset;
 914         const char *prefix;
 915         int line_termination, inter_name_termination;
 916
 917         line_termination = opt->line_termination;
 918         inter_name_termination = '\t';
 919         if (!line_termination)
 920                 inter_name_termination = 0;
 921
 922         if (rev->loginfo && !rev->no_commit_id)
 923                 show_log(rev);
 924
 925         if (opt->output_format & DIFF_FORMAT_RAW) {
 926                 offset = strlen(COLONS) - num_parent;
 927                 if (offset < 0)
 928                         offset = 0;
 929                 prefix = COLONS + offset;
 930
 931                 /* Show the modes */
 932                 for (i = 0; i < num_parent; i++) {
 933                         printf("%s%06o", prefix, p->parent[i].mode);
 934                         prefix = " ";
 935                 }
 936                 printf("%s%06o", prefix, p->mode);
 937
 938                 /* Show sha1's */
 939                 for (i = 0; i < num_parent; i++)
 940                         printf(" %s", diff_unique_abbrev(p->parent[i].sha1,
 941                                                          opt->abbrev));
 942                 printf(" %s ", diff_unique_abbrev(p->sha1, opt->abbrev));
 943         }
 944
 945         if (opt->output_format & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS)) {
 946                 for (i = 0; i < num_parent; i++)
 947                         putchar(p->parent[i].status);
 948                 putchar(inter_name_termination);
 949         }
 950
 951         write_name_quoted(p->path, stdout, line_termination);
 952 }
 953
 954 void show_combined_diff(struct combine_diff_path *p,
 955                        int num_parent,
 956                        int dense,
 957                        struct rev_info *rev)
 958 {
 959         struct diff_options *opt = &rev->diffopt;
 960         if (!p->len)
 961                 return;
 962         if (opt->output_format & (DIFF_FORMAT_RAW |
 963                                   DIFF_FORMAT_NAME |
 964                                   DIFF_FORMAT_NAME_STATUS))
 965                 show_raw_diff(p, num_parent, rev);
 966         else if (opt->output_format & DIFF_FORMAT_PATCH)
 967                 show_patch_diff(p, num_parent, dense, rev);
 968 }
 969
 970 void diff_tree_combined(const unsigned char *sha1,
 971                         const unsigned char parent[][20],
 972                         int num_parent,
 973                         int dense,
 974                         struct rev_info *rev)
 975 {
 976         struct diff_options *opt = &rev->diffopt;
 977         struct diff_options diffopts;
 978         struct combine_diff_path *p, *paths = NULL;
 979         int i, num_paths, needsep, show_log_first;
 980
 981         diffopts = *opt;
 982         diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
 983         DIFF_OPT_SET(&diffopts, RECURSIVE);
 984         DIFF_OPT_CLR(&diffopts, ALLOW_EXTERNAL);
 985
 986         show_log_first = !!rev->loginfo && !rev->no_commit_id;
 987         needsep = 0;
 988         /* find set of paths that everybody touches */
 989         for (i = 0; i < num_parent; i++) {
 990                 /* show stat against the first parent even
 991                  * when doing combined diff.
 992                  */
 993                 int stat_opt = (opt->output_format &
 994                                 (DIFF_FORMAT_NUMSTAT|DIFF_FORMAT_DIFFSTAT));
 995                 if (i == 0 && stat_opt)
 996                         diffopts.output_format = stat_opt;
 997                 else
 998                         diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
 999                 diff_tree_sha1(parent[i], sha1, "", &diffopts);
1000                 diffcore_std(&diffopts);
1001                 paths = intersect_paths(paths, i, num_parent);
1002
1003                 if (show_log_first && i == 0) {
1004                         show_log(rev);
1005                         if (rev->verbose_header && opt->output_format)
1006                                 putchar(opt->line_termination);
1007                 }
1008                 diff_flush(&diffopts);
1009         }
1010
1011         /* find out surviving paths */
1012         for (num_paths = 0, p = paths; p; p = p->next) {
1013                 if (p->len)
1014                         num_paths++;
1015         }
1016         if (num_paths) {
1017                 if (opt->output_format & (DIFF_FORMAT_RAW |
1018                                           DIFF_FORMAT_NAME |
1019                                           DIFF_FORMAT_NAME_STATUS)) {
1020                         for (p = paths; p; p = p->next) {
1021                                 if (p->len)
1022                                         show_raw_diff(p, num_parent, rev);
1023                         }
1024                         needsep = 1;
1025                 }
1026                 else if (opt->output_format &
1027                          (DIFF_FORMAT_NUMSTAT|DIFF_FORMAT_DIFFSTAT))
1028                         needsep = 1;
1029                 if (opt->output_format & DIFF_FORMAT_PATCH) {
1030                         if (needsep)
1031                                 putchar(opt->line_termination);
1032                         for (p = paths; p; p = p->next) {
1033                                 if (p->len)
1034                                         show_patch_diff(p, num_parent, dense,
1035                                                         rev);
1036                         }
1037                 }
1038         }
1039
1040         /* Clean things up */
1041         while (paths) {
1042                 struct combine_diff_path *tmp = paths;
1043                 paths = paths->next;
1044                 free(tmp);
1045         }
1046 }
1047
1048 void diff_tree_combined_merge(const unsigned char *sha1,
1049                              int dense, struct rev_info *rev)
1050 {
1051         int num_parent;
1052         const unsigned char (*parent)[20];
1053         struct commit *commit = lookup_commit(sha1);
1054         struct commit_list *parents;
1055
1056         /* count parents */
1057         for (parents = commit->parents, num_parent = 0;
1058              parents;
1059              parents = parents->next, num_parent++)
1060                 ; /* nothing */
1061
1062         parent = xmalloc(num_parent * sizeof(*parent));
1063         for (parents = commit->parents, num_parent = 0;
1064              parents;
1065              parents = parents->next, num_parent++)
1066                 hashcpy((unsigned char *)(parent + num_parent),
1067                         parents->item->object.sha1);
1068         diff_tree_combined(sha1, parent, num_parent, dense, rev);
1069 }