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         struct lline *next_lost;
  84         char *bol;
  85         int len;
  86         /* bit 0 up to (N-1) are on if the parent has this line (i.e.
  87          * we did not change it).
  88          * bit N is used for "interesting" lines, including context.
  89          * bit (N+1) is used for "do not show deletion before this".
  90          */
  91         unsigned long flag;
  92         unsigned long *p_lno;
  93 };
  94
  95 static char *grab_blob(const unsigned char *sha1, unsigned int mode, unsigned long *size)
  96 {
  97         char *blob;
  98         enum object_type type;
  99
 100         if (S_ISGITLINK(mode)) {
 101                 blob = xmalloc(100);
 102                 *size = snprintf(blob, 100,
 103                                  "Subproject commit %s\n", sha1_to_hex(sha1));
 104         } else if (is_null_sha1(sha1)) {
 105                 /* deleted blob */
 106                 *size = 0;
 107                 return xcalloc(1, 1);
 108         } else {
 109                 blob = read_sha1_file(sha1, &type, size);
 110                 if (type != OBJ_BLOB)
 111                         die("object '%s' is not a blob!", sha1_to_hex(sha1));
 112         }
 113         return blob;
 114 }
 115
 116 static void append_lost(struct sline *sline, int n, const char *line, int len)
 117 {
 118         struct lline *lline;
 119         unsigned long this_mask = (1UL<<n);
 120         if (line[len-1] == '\n')
 121                 len--;
 122
 123         /* Check to see if we can squash things */
 124         if (sline->lost_head) {
 125                 lline = sline->next_lost;
 126                 while (lline) {
 127                         if (lline->len == len &&
 128                             !memcmp(lline->line, line, len)) {
 129                                 lline->parent_map |= this_mask;
 130                                 sline->next_lost = lline->next;
 131                                 return;
 132                         }
 133                         lline = lline->next;
 134                 }
 135         }
 136
 137         lline = xmalloc(sizeof(*lline) + len + 1);
 138         lline->len = len;
 139         lline->next = NULL;
 140         lline->parent_map = this_mask;
 141         memcpy(lline->line, line, len);
 142         lline->line[len] = 0;
 143         *sline->lost_tail = lline;
 144         sline->lost_tail = &lline->next;
 145         sline->next_lost = NULL;
 146 }
 147
 148 struct combine_diff_state {
 149         unsigned int lno;
 150         int ob, on, nb, nn;
 151         unsigned long nmask;
 152         int num_parent;
 153         int n;
 154         struct sline *sline;
 155         struct sline *lost_bucket;
 156 };
 157
 158 static void consume_line(void *state_, char *line, unsigned long len)
 159 {
 160         struct combine_diff_state *state = state_;
 161         if (5 < len && !memcmp("@@ -", line, 4)) {
 162                 if (parse_hunk_header(line, len,
 163                                       &state->ob, &state->on,
 164                                       &state->nb, &state->nn))
 165                         return;
 166                 state->lno = state->nb;
 167                 if (state->nn == 0) {
 168                         /* @@ -X,Y +N,0 @@ removed Y lines
 169                          * that would have come *after* line N
 170                          * in the result.  Our lost buckets hang
 171                          * to the line after the removed lines,
 172                          *
 173                          * Note that this is correct even when N == 0,
 174                          * in which case the hunk removes the first
 175                          * line in the file.
 176                          */
 177                         state->lost_bucket = &state->sline[state->nb];
 178                         if (!state->nb)
 179                                 state->nb = 1;
 180                 } else {
 181                         state->lost_bucket = &state->sline[state->nb-1];
 182                 }
 183                 if (!state->sline[state->nb-1].p_lno)
 184                         state->sline[state->nb-1].p_lno =
 185                                 xcalloc(state->num_parent,
 186                                         sizeof(unsigned long));
 187                 state->sline[state->nb-1].p_lno[state->n] = state->ob;
 188                 state->lost_bucket->next_lost = state->lost_bucket->lost_head;
 189                 return;
 190         }
 191         if (!state->lost_bucket)
 192                 return; /* not in any hunk yet */
 193         switch (line[0]) {
 194         case '-':
 195                 append_lost(state->lost_bucket, state->n, line+1, len-1);
 196                 break;
 197         case '+':
 198                 state->sline[state->lno-1].flag |= state->nmask;
 199                 state->lno++;
 200                 break;
 201         }
 202 }
 203
 204 static void combine_diff(const unsigned char *parent, unsigned int mode,
 205                          mmfile_t *result_file,
 206                          struct sline *sline, unsigned int cnt, int n,
 207                          int num_parent, int result_deleted)
 208 {
 209         unsigned int p_lno, lno;
 210         unsigned long nmask = (1UL << n);
 211         xpparam_t xpp;
 212         xdemitconf_t xecfg;
 213         mmfile_t parent_file;
 214         struct combine_diff_state state;
 215         unsigned long sz;
 216
 217         if (result_deleted)
 218                 return; /* result deleted */
 219
 220         parent_file.ptr = grab_blob(parent, mode, &sz);
 221         parent_file.size = sz;
 222         memset(&xpp, 0, sizeof(xpp));
 223         xpp.flags = 0;
 224         memset(&xecfg, 0, sizeof(xecfg));
 225         memset(&state, 0, sizeof(state));
 226         state.nmask = nmask;
 227         state.sline = sline;
 228         state.lno = 1;
 229         state.num_parent = num_parent;
 230         state.n = n;
 231
 232         xdi_diff_outf(&parent_file, result_file, consume_line, &state,
 233                       &xpp, &xecfg);
 234         free(parent_file.ptr);
 235
 236         /* Assign line numbers for this parent.
 237          *
 238          * sline[lno].p_lno[n] records the first line number
 239          * (counting from 1) for parent N if the final hunk display
 240          * started by showing sline[lno] (possibly showing the lost
 241          * lines attached to it first).
 242          */
 243         for (lno = 0,  p_lno = 1; lno <= cnt; lno++) {
 244                 struct lline *ll;
 245                 sline[lno].p_lno[n] = p_lno;
 246
 247                 /* How many lines would this sline advance the p_lno? */
 248                 ll = sline[lno].lost_head;
 249                 while (ll) {
 250                         if (ll->parent_map & nmask)
 251                                 p_lno++; /* '-' means parent had it */
 252                         ll = ll->next;
 253                 }
 254                 if (lno < cnt && !(sline[lno].flag & nmask))
 255                         p_lno++; /* no '+' means parent had it */
 256         }
 257         sline[lno].p_lno[n] = p_lno; /* trailer */
 258 }
 259
 260 static unsigned long context = 3;
 261 static char combine_marker = '@';
 262
 263 static int interesting(struct sline *sline, unsigned long all_mask)
 264 {
 265         /* If some parents lost lines here, or if we have added to
 266          * some parent, it is interesting.
 267          */
 268         return ((sline->flag & all_mask) || sline->lost_head);
 269 }
 270
 271 static unsigned long adjust_hunk_tail(struct sline *sline,
 272                                       unsigned long all_mask,
 273                                       unsigned long hunk_begin,
 274                                       unsigned long i)
 275 {
 276         /* i points at the first uninteresting line.  If the last line
 277          * of the hunk was interesting only because it has some
 278          * deletion, then it is not all that interesting for the
 279          * purpose of giving trailing context lines.  This is because
 280          * we output '-' line and then unmodified sline[i-1] itself in
 281          * that case which gives us one extra context line.
 282          */
 283         if ((hunk_begin + 1 <= i) && !(sline[i-1].flag & all_mask))
 284                 i--;
 285         return i;
 286 }
 287
 288 static unsigned long find_next(struct sline *sline,
 289                                unsigned long mark,
 290                                unsigned long i,
 291                                unsigned long cnt,
 292                                int look_for_uninteresting)
 293 {
 294         /* We have examined up to i-1 and are about to look at i.
 295          * Find next interesting or uninteresting line.  Here,
 296          * "interesting" does not mean interesting(), but marked by
 297          * the give_context() function below (i.e. it includes context
 298          * lines that are not interesting to interesting() function
 299          * that are surrounded by interesting() ones.
 300          */
 301         while (i <= cnt)
 302                 if (look_for_uninteresting
 303                     ? !(sline[i].flag & mark)
 304                     : (sline[i].flag & mark))
 305                         return i;
 306                 else
 307                         i++;
 308         return i;
 309 }
 310
 311 static int give_context(struct sline *sline, unsigned long cnt, int num_parent)
 312 {
 313         unsigned long all_mask = (1UL<<num_parent) - 1;
 314         unsigned long mark = (1UL<<num_parent);
 315         unsigned long no_pre_delete = (2UL<<num_parent);
 316         unsigned long i;
 317
 318         /* Two groups of interesting lines may have a short gap of
 319          * uninteresting lines.  Connect such groups to give them a
 320          * bit of context.
 321          *
 322          * We first start from what the interesting() function says,
 323          * and mark them with "mark", and paint context lines with the
 324          * mark.  So interesting() would still say false for such context
 325          * lines but they are treated as "interesting" in the end.
 326          */
 327         i = find_next(sline, mark, 0, cnt, 0);
 328         if (cnt < i)
 329                 return 0;
 330
 331         while (i <= cnt) {
 332                 unsigned long j = (context < i) ? (i - context) : 0;
 333                 unsigned long k;
 334
 335                 /* Paint a few lines before the first interesting line. */
 336                 while (j < i)
 337                         sline[j++].flag |= mark | no_pre_delete;
 338
 339         again:
 340                 /* we know up to i is to be included.  where does the
 341                  * next uninteresting one start?
 342                  */
 343                 j = find_next(sline, mark, i, cnt, 1);
 344                 if (cnt < j)
 345                         break; /* the rest are all interesting */
 346
 347                 /* lookahead context lines */
 348                 k = find_next(sline, mark, j, cnt, 0);
 349                 j = adjust_hunk_tail(sline, all_mask, i, j);
 350
 351                 if (k < j + context) {
 352                         /* k is interesting and [j,k) are not, but
 353                          * paint them interesting because the gap is small.
 354                          */
 355                         while (j < k)
 356                                 sline[j++].flag |= mark;
 357                         i = k;
 358                         goto again;
 359                 }
 360
 361                 /* j is the first uninteresting line and there is
 362                  * no overlap beyond it within context lines.  Paint
 363                  * the trailing edge a bit.
 364                  */
 365                 i = k;
 366                 k = (j + context < cnt+1) ? j + context : cnt+1;
 367                 while (j < k)
 368                         sline[j++].flag |= mark;
 369         }
 370         return 1;
 371 }
 372
 373 static int make_hunks(struct sline *sline, unsigned long cnt,
 374                        int num_parent, int dense)
 375 {
 376         unsigned long all_mask = (1UL<<num_parent) - 1;
 377         unsigned long mark = (1UL<<num_parent);
 378         unsigned long i;
 379         int has_interesting = 0;
 380
 381         for (i = 0; i <= cnt; i++) {
 382                 if (interesting(&sline[i], all_mask))
 383                         sline[i].flag |= mark;
 384                 else
 385                         sline[i].flag &= ~mark;
 386         }
 387         if (!dense)
 388                 return give_context(sline, cnt, num_parent);
 389
 390         /* Look at each hunk, and if we have changes from only one
 391          * parent, or the changes are the same from all but one
 392          * parent, mark that uninteresting.
 393          */
 394         i = 0;
 395         while (i <= cnt) {
 396                 unsigned long j, hunk_begin, hunk_end;
 397                 unsigned long same_diff;
 398                 while (i <= cnt && !(sline[i].flag & mark))
 399                         i++;
 400                 if (cnt < i)
 401                         break; /* No more interesting hunks */
 402                 hunk_begin = i;
 403                 for (j = i + 1; j <= cnt; j++) {
 404                         if (!(sline[j].flag & mark)) {
 405                                 /* Look beyond the end to see if there
 406                                  * is an interesting line after this
 407                                  * hunk within context span.
 408                                  */
 409                                 unsigned long la; /* lookahead */
 410                                 int contin = 0;
 411                                 la = adjust_hunk_tail(sline, all_mask,
 412                                                      hunk_begin, j);
 413                                 la = (la + context < cnt + 1) ?
 414                                         (la + context) : cnt + 1;
 415                                 while (j <= --la) {
 416                                         if (sline[la].flag & mark) {
 417                                                 contin = 1;
 418                                                 break;
 419                                         }
 420                                 }
 421                                 if (!contin)
 422                                         break;
 423                                 j = la;
 424                         }
 425                 }
 426                 hunk_end = j;
 427
 428                 /* [i..hunk_end) are interesting.  Now is it really
 429                  * interesting?  We check if there are only two versions
 430                  * and the result matches one of them.  That is, we look
 431                  * at:
 432                  *   (+) line, which records lines added to which parents;
 433                  *       this line appears in the result.
 434                  *   (-) line, which records from what parents the line
 435                  *       was removed; this line does not appear in the result.
 436                  * then check the set of parents the result has difference
 437                  * from, from all lines.  If there are lines that has
 438                  * different set of parents that the result has differences
 439                  * from, that means we have more than two versions.
 440                  *
 441                  * Even when we have only two versions, if the result does
 442                  * not match any of the parents, the it should be considered
 443                  * interesting.  In such a case, we would have all '+' line.
 444                  * After passing the above "two versions" test, that would
 445                  * appear as "the same set of parents" to be "all parents".
 446                  */
 447                 same_diff = 0;
 448                 has_interesting = 0;
 449                 for (j = i; j < hunk_end && !has_interesting; j++) {
 450                         unsigned long this_diff = sline[j].flag & all_mask;
 451                         struct lline *ll = sline[j].lost_head;
 452                         if (this_diff) {
 453                                 /* This has some changes.  Is it the
 454                                  * same as others?
 455                                  */
 456                                 if (!same_diff)
 457                                         same_diff = this_diff;
 458                                 else if (same_diff != this_diff) {
 459                                         has_interesting = 1;
 460                                         break;
 461                                 }
 462                         }
 463                         while (ll && !has_interesting) {
 464                                 /* Lost this line from these parents;
 465                                  * who are they?  Are they the same?
 466                                  */
 467                                 this_diff = ll->parent_map;
 468                                 if (!same_diff)
 469                                         same_diff = this_diff;
 470                                 else if (same_diff != this_diff) {
 471                                         has_interesting = 1;
 472                                 }
 473                                 ll = ll->next;
 474                         }
 475                 }
 476
 477                 if (!has_interesting && same_diff != all_mask) {
 478                         /* This hunk is not that interesting after all */
 479                         for (j = hunk_begin; j < hunk_end; j++)
 480                                 sline[j].flag &= ~mark;
 481                 }
 482                 i = hunk_end;
 483         }
 484
 485         has_interesting = give_context(sline, cnt, num_parent);
 486         return has_interesting;
 487 }
 488
 489 static void show_parent_lno(struct sline *sline, unsigned long l0, unsigned long l1, int n, unsigned long null_context)
 490 {
 491         l0 = sline[l0].p_lno[n];
 492         l1 = sline[l1].p_lno[n];
 493         printf(" -%lu,%lu", l0, l1-l0-null_context);
 494 }
 495
 496 static int hunk_comment_line(const char *bol)
 497 {
 498         int ch;
 499
 500         if (!bol)
 501                 return 0;
 502         ch = *bol & 0xff;
 503         return (isalpha(ch) || ch == '_' || ch == '$');
 504 }
 505
 506 static void show_line_to_eol(const char *line, int len, const char *reset)
 507 {
 508         int saw_cr_at_eol = 0;
 509         if (len < 0)
 510                 len = strlen(line);
 511         saw_cr_at_eol = (len && line[len-1] == '\r');
 512
 513         printf("%.*s%s%s\n", len - saw_cr_at_eol, line,
 514                reset,
 515                saw_cr_at_eol ? "\r" : "");
 516 }
 517
 518 static void dump_sline(struct sline *sline, unsigned long cnt, int num_parent,
 519                        int use_color, int result_deleted)
 520 {
 521         unsigned long mark = (1UL<<num_parent);
 522         unsigned long no_pre_delete = (2UL<<num_parent);
 523         int i;
 524         unsigned long lno = 0;
 525         const char *c_frag = diff_get_color(use_color, DIFF_FRAGINFO);
 526         const char *c_func = diff_get_color(use_color, DIFF_FUNCINFO);
 527         const char *c_new = diff_get_color(use_color, DIFF_FILE_NEW);
 528         const char *c_old = diff_get_color(use_color, DIFF_FILE_OLD);
 529         const char *c_plain = diff_get_color(use_color, DIFF_PLAIN);
 530         const char *c_reset = diff_get_color(use_color, DIFF_RESET);
 531
 532         if (result_deleted)
 533                 return; /* result deleted */
 534
 535         while (1) {
 536                 unsigned long hunk_end;
 537                 unsigned long rlines;
 538                 const char *hunk_comment = NULL;
 539                 unsigned long null_context = 0;
 540
 541                 while (lno <= cnt && !(sline[lno].flag & mark)) {
 542                         if (hunk_comment_line(sline[lno].bol))
 543                                 hunk_comment = sline[lno].bol;
 544                         lno++;
 545                 }
 546                 if (cnt < lno)
 547                         break;
 548                 else {
 549                         for (hunk_end = lno + 1; hunk_end <= cnt; hunk_end++)
 550                                 if (!(sline[hunk_end].flag & mark))
 551                                         break;
 552                 }
 553                 rlines = hunk_end - lno;
 554                 if (cnt < hunk_end)
 555                         rlines--; /* pointing at the last delete hunk */
 556
 557                 if (!context) {
 558                         /*
 559                          * Even when running with --unified=0, all
 560                          * lines in the hunk needs to be processed in
 561                          * the loop below in order to show the
 562                          * deletion recorded in lost_head.  However,
 563                          * we do not want to show the resulting line
 564                          * with all blank context markers in such a
 565                          * case.  Compensate.
 566                          */
 567                         unsigned long j;
 568                         for (j = lno; j < hunk_end; j++)
 569                                 if (!(sline[j].flag & (mark-1)))
 570                                         null_context++;
 571                         rlines -= null_context;
 572                 }
 573
 574                 fputs(c_frag, stdout);
 575                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 576                 for (i = 0; i < num_parent; i++)
 577                         show_parent_lno(sline, lno, hunk_end, i, null_context);
 578                 printf(" +%lu,%lu ", lno+1, rlines);
 579                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 580
 581                 if (hunk_comment) {
 582                         int comment_end = 0;
 583                         for (i = 0; i < 40; i++) {
 584                                 int ch = hunk_comment[i] & 0xff;
 585                                 if (!ch || ch == '\n')
 586                                         break;
 587                                 if (!isspace(ch))
 588                                     comment_end = i;
 589                         }
 590                         if (comment_end)
 591                                 printf("%s%s %s%s", c_reset,
 592                                                     c_plain, c_reset,
 593                                                     c_func);
 594                         for (i = 0; i < comment_end; i++)
 595                                 putchar(hunk_comment[i]);
 596                 }
 597
 598                 printf("%s\n", c_reset);
 599                 while (lno < hunk_end) {
 600                         struct lline *ll;
 601                         int j;
 602                         unsigned long p_mask;
 603                         struct sline *sl = &sline[lno++];
 604                         ll = (sl->flag & no_pre_delete) ? NULL : sl->lost_head;
 605                         while (ll) {
 606                                 fputs(c_old, stdout);
 607                                 for (j = 0; j < num_parent; j++) {
 608                                         if (ll->parent_map & (1UL<<j))
 609                                                 putchar('-');
 610                                         else
 611                                                 putchar(' ');
 612                                 }
 613                                 show_line_to_eol(ll->line, -1, c_reset);
 614                                 ll = ll->next;
 615                         }
 616                         if (cnt < lno)
 617                                 break;
 618                         p_mask = 1;
 619                         if (!(sl->flag & (mark-1))) {
 620                                 /*
 621                                  * This sline was here to hang the
 622                                  * lost lines in front of it.
 623                                  */
 624                                 if (!context)
 625                                         continue;
 626                                 fputs(c_plain, stdout);
 627                         }
 628                         else
 629                                 fputs(c_new, stdout);
 630                         for (j = 0; j < num_parent; j++) {
 631                                 if (p_mask & sl->flag)
 632                                         putchar('+');
 633                                 else
 634                                         putchar(' ');
 635                                 p_mask <<= 1;
 636                         }
 637                         show_line_to_eol(sl->bol, sl->len, c_reset);
 638                 }
 639         }
 640 }
 641
 642 static void reuse_combine_diff(struct sline *sline, unsigned long cnt,
 643                                int i, int j)
 644 {
 645         /* We have already examined parent j and we know parent i
 646          * and parent j are the same, so reuse the combined result
 647          * of parent j for parent i.
 648          */
 649         unsigned long lno, imask, jmask;
 650         imask = (1UL<<i);
 651         jmask = (1UL<<j);
 652
 653         for (lno = 0; lno <= cnt; lno++) {
 654                 struct lline *ll = sline->lost_head;
 655                 sline->p_lno[i] = sline->p_lno[j];
 656                 while (ll) {
 657                         if (ll->parent_map & jmask)
 658                                 ll->parent_map |= imask;
 659                         ll = ll->next;
 660                 }
 661                 if (sline->flag & jmask)
 662                         sline->flag |= imask;
 663                 sline++;
 664         }
 665         /* the overall size of the file (sline[cnt]) */
 666         sline->p_lno[i] = sline->p_lno[j];
 667 }
 668
 669 static void dump_quoted_path(const char *head,
 670                              const char *prefix,
 671                              const char *path,
 672                              const char *c_meta, const char *c_reset)
 673 {
 674         static struct strbuf buf = STRBUF_INIT;
 675
 676         strbuf_reset(&buf);
 677         strbuf_addstr(&buf, c_meta);
 678         strbuf_addstr(&buf, head);
 679         quote_two_c_style(&buf, prefix, path, 0);
 680         strbuf_addstr(&buf, c_reset);
 681         puts(buf.buf);
 682 }
 683
 684 static void show_patch_diff(struct combine_diff_path *elem, int num_parent,
 685                             int dense, struct rev_info *rev)
 686 {
 687         struct diff_options *opt = &rev->diffopt;
 688         unsigned long result_size, cnt, lno;
 689         int result_deleted = 0;
 690         char *result, *cp;
 691         struct sline *sline; /* survived lines */
 692         int mode_differs = 0;
 693         int i, show_hunks;
 694         int working_tree_file = is_null_sha1(elem->sha1);
 695         int abbrev = DIFF_OPT_TST(opt, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
 696         const char *a_prefix, *b_prefix;
 697         mmfile_t result_file;
 698
 699         context = opt->context;
 700         a_prefix = opt->a_prefix ? opt->a_prefix : "a/";
 701         b_prefix = opt->b_prefix ? opt->b_prefix : "b/";
 702
 703         /* Read the result of merge first */
 704         if (!working_tree_file)
 705                 result = grab_blob(elem->sha1, elem->mode, &result_size);
 706         else {
 707                 /* Used by diff-tree to read from the working tree */
 708                 struct stat st;
 709                 int fd = -1;
 710
 711                 if (lstat(elem->path, &st) < 0)
 712                         goto deleted_file;
 713
 714                 if (S_ISLNK(st.st_mode)) {
 715                         struct strbuf buf = STRBUF_INIT;
 716
 717                         if (strbuf_readlink(&buf, elem->path, st.st_size) < 0) {
 718                                 error("readlink(%s): %s", elem->path,
 719                                       strerror(errno));
 720                                 return;
 721                         }
 722                         result_size = buf.len;
 723                         result = strbuf_detach(&buf, NULL);
 724                         elem->mode = canon_mode(st.st_mode);
 725                 } else if (S_ISDIR(st.st_mode)) {
 726                         unsigned char sha1[20];
 727                         if (resolve_gitlink_ref(elem->path, "HEAD", sha1) < 0)
 728                                 result = grab_blob(elem->sha1, elem->mode, &result_size);
 729                         else
 730                                 result = grab_blob(sha1, elem->mode, &result_size);
 731                 } else if (0 <= (fd = open(elem->path, O_RDONLY))) {
 732                         size_t len = xsize_t(st.st_size);
 733                         ssize_t done;
 734                         int is_file, i;
 735
 736                         elem->mode = canon_mode(st.st_mode);
 737                         /* if symlinks don't work, assume symlink if all parents
 738                          * are symlinks
 739                          */
 740                         is_file = has_symlinks;
 741                         for (i = 0; !is_file && i < num_parent; i++)
 742                                 is_file = !S_ISLNK(elem->parent[i].mode);
 743                         if (!is_file)
 744                                 elem->mode = canon_mode(S_IFLNK);
 745
 746                         result_size = len;
 747                         result = xmalloc(len + 1);
 748
 749                         done = read_in_full(fd, result, len);
 750                         if (done < 0)
 751                                 die_errno("read error '%s'", elem->path);
 752                         else if (done < len)
 753                                 die("early EOF '%s'", elem->path);
 754
 755                         result[len] = 0;
 756
 757                         /* If not a fake symlink, apply filters, e.g. autocrlf */
 758                         if (is_file) {
 759                                 struct strbuf buf = STRBUF_INIT;
 760
 761                                 if (convert_to_git(elem->path, result, len, &buf, safe_crlf)) {
 762                                         free(result);
 763                                         result = strbuf_detach(&buf, &len);
 764                                         result_size = len;
 765                                 }
 766                         }
 767                 }
 768                 else {
 769                 deleted_file:
 770                         result_deleted = 1;
 771                         result_size = 0;
 772                         elem->mode = 0;
 773                         result = xcalloc(1, 1);
 774                 }
 775
 776                 if (0 <= fd)
 777                         close(fd);
 778         }
 779
 780         for (cnt = 0, cp = result; cp < result + result_size; cp++) {
 781                 if (*cp == '\n')
 782                         cnt++;
 783         }
 784         if (result_size && result[result_size-1] != '\n')
 785                 cnt++; /* incomplete line */
 786
 787         sline = xcalloc(cnt+2, sizeof(*sline));
 788         sline[0].bol = result;
 789         for (lno = 0; lno <= cnt + 1; lno++) {
 790                 sline[lno].lost_tail = &sline[lno].lost_head;
 791                 sline[lno].flag = 0;
 792         }
 793         for (lno = 0, cp = result; cp < result + result_size; cp++) {
 794                 if (*cp == '\n') {
 795                         sline[lno].len = cp - sline[lno].bol;
 796                         lno++;
 797                         if (lno < cnt)
 798                                 sline[lno].bol = cp + 1;
 799                 }
 800         }
 801         if (result_size && result[result_size-1] != '\n')
 802                 sline[cnt-1].len = result_size - (sline[cnt-1].bol - result);
 803
 804         result_file.ptr = result;
 805         result_file.size = result_size;
 806
 807         /* Even p_lno[cnt+1] is valid -- that is for the end line number
 808          * for deletion hunk at the end.
 809          */
 810         sline[0].p_lno = xcalloc((cnt+2) * num_parent, sizeof(unsigned long));
 811         for (lno = 0; lno <= cnt; lno++)
 812                 sline[lno+1].p_lno = sline[lno].p_lno + num_parent;
 813
 814         for (i = 0; i < num_parent; i++) {
 815                 int j;
 816                 for (j = 0; j < i; j++) {
 817                         if (!hashcmp(elem->parent[i].sha1,
 818                                      elem->parent[j].sha1)) {
 819                                 reuse_combine_diff(sline, cnt, i, j);
 820                                 break;
 821                         }
 822                 }
 823                 if (i <= j)
 824                         combine_diff(elem->parent[i].sha1,
 825                                      elem->parent[i].mode,
 826                                      &result_file, sline,
 827                                      cnt, i, num_parent, result_deleted);
 828                 if (elem->parent[i].mode != elem->mode)
 829                         mode_differs = 1;
 830         }
 831
 832         show_hunks = make_hunks(sline, cnt, num_parent, dense);
 833
 834         if (show_hunks || mode_differs || working_tree_file) {
 835                 const char *abb;
 836                 int use_color = DIFF_OPT_TST(opt, COLOR_DIFF);
 837                 const char *c_meta = diff_get_color(use_color, DIFF_METAINFO);
 838                 const char *c_reset = diff_get_color(use_color, DIFF_RESET);
 839                 int added = 0;
 840                 int deleted = 0;
 841
 842                 if (rev->loginfo && !rev->no_commit_id)
 843                         show_log(rev);
 844                 dump_quoted_path(dense ? "diff --cc " : "diff --combined ",
 845                                  "", elem->path, c_meta, c_reset);
 846                 printf("%sindex ", c_meta);
 847                 for (i = 0; i < num_parent; i++) {
 848                         abb = find_unique_abbrev(elem->parent[i].sha1,
 849                                                  abbrev);
 850                         printf("%s%s", i ? "," : "", abb);
 851                 }
 852                 abb = find_unique_abbrev(elem->sha1, abbrev);
 853                 printf("..%s%s\n", abb, c_reset);
 854
 855                 if (mode_differs) {
 856                         deleted = !elem->mode;
 857
 858                         /* We say it was added if nobody had it */
 859                         added = !deleted;
 860                         for (i = 0; added && i < num_parent; i++)
 861                                 if (elem->parent[i].status !=
 862                                     DIFF_STATUS_ADDED)
 863                                         added = 0;
 864                         if (added)
 865                                 printf("%snew file mode %06o",
 866                                        c_meta, elem->mode);
 867                         else {
 868                                 if (deleted)
 869                                         printf("%sdeleted file ", c_meta);
 870                                 printf("mode ");
 871                                 for (i = 0; i < num_parent; i++) {
 872                                         printf("%s%06o", i ? "," : "",
 873                                                elem->parent[i].mode);
 874                                 }
 875                                 if (elem->mode)
 876                                         printf("..%06o", elem->mode);
 877                         }
 878                         printf("%s\n", c_reset);
 879                 }
 880                 if (added)
 881                         dump_quoted_path("--- ", "", "/dev/null",
 882                                          c_meta, c_reset);
 883                 else
 884                         dump_quoted_path("--- ", a_prefix, elem->path,
 885                                          c_meta, c_reset);
 886                 if (deleted)
 887                         dump_quoted_path("+++ ", "", "/dev/null",
 888                                          c_meta, c_reset);
 889                 else
 890                         dump_quoted_path("+++ ", b_prefix, elem->path,
 891                                          c_meta, c_reset);
 892                 dump_sline(sline, cnt, num_parent,
 893                            DIFF_OPT_TST(opt, COLOR_DIFF), result_deleted);
 894         }
 895         free(result);
 896
 897         for (lno = 0; lno < cnt; lno++) {
 898                 if (sline[lno].lost_head) {
 899                         struct lline *ll = sline[lno].lost_head;
 900                         while (ll) {
 901                                 struct lline *tmp = ll;
 902                                 ll = ll->next;
 903                                 free(tmp);
 904                         }
 905                 }
 906         }
 907         free(sline[0].p_lno);
 908         free(sline);
 909 }
 910
 911 #define COLONS "::::::::::::::::::::::::::::::::"
 912
 913 static void show_raw_diff(struct combine_diff_path *p, int num_parent, struct rev_info *rev)
 914 {
 915         struct diff_options *opt = &rev->diffopt;
 916         int i, offset;
 917         const char *prefix;
 918         int line_termination, inter_name_termination;
 919
 920         line_termination = opt->line_termination;
 921         inter_name_termination = '\t';
 922         if (!line_termination)
 923                 inter_name_termination = 0;
 924
 925         if (rev->loginfo && !rev->no_commit_id)
 926                 show_log(rev);
 927
 928         if (opt->output_format & DIFF_FORMAT_RAW) {
 929                 offset = strlen(COLONS) - num_parent;
 930                 if (offset < 0)
 931                         offset = 0;
 932                 prefix = COLONS + offset;
 933
 934                 /* Show the modes */
 935                 for (i = 0; i < num_parent; i++) {
 936                         printf("%s%06o", prefix, p->parent[i].mode);
 937                         prefix = " ";
 938                 }
 939                 printf("%s%06o", prefix, p->mode);
 940
 941                 /* Show sha1's */
 942                 for (i = 0; i < num_parent; i++)
 943                         printf(" %s", diff_unique_abbrev(p->parent[i].sha1,
 944                                                          opt->abbrev));
 945                 printf(" %s ", diff_unique_abbrev(p->sha1, opt->abbrev));
 946         }
 947
 948         if (opt->output_format & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS)) {
 949                 for (i = 0; i < num_parent; i++)
 950                         putchar(p->parent[i].status);
 951                 putchar(inter_name_termination);
 952         }
 953
 954         write_name_quoted(p->path, stdout, line_termination);
 955 }
 956
 957 void show_combined_diff(struct combine_diff_path *p,
 958                        int num_parent,
 959                        int dense,
 960                        struct rev_info *rev)
 961 {
 962         struct diff_options *opt = &rev->diffopt;
 963         if (!p->len)
 964                 return;
 965         if (opt->output_format & (DIFF_FORMAT_RAW |
 966                                   DIFF_FORMAT_NAME |
 967                                   DIFF_FORMAT_NAME_STATUS))
 968                 show_raw_diff(p, num_parent, rev);
 969         else if (opt->output_format & DIFF_FORMAT_PATCH)
 970                 show_patch_diff(p, num_parent, dense, rev);
 971 }
 972
 973 void diff_tree_combined(const unsigned char *sha1,
 974                         const unsigned char parent[][20],
 975                         int num_parent,
 976                         int dense,
 977                         struct rev_info *rev)
 978 {
 979         struct diff_options *opt = &rev->diffopt;
 980         struct diff_options diffopts;
 981         struct combine_diff_path *p, *paths = NULL;
 982         int i, num_paths, needsep, show_log_first;
 983
 984         diffopts = *opt;
 985         diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
 986         DIFF_OPT_SET(&diffopts, RECURSIVE);
 987         DIFF_OPT_CLR(&diffopts, ALLOW_EXTERNAL);
 988
 989         show_log_first = !!rev->loginfo && !rev->no_commit_id;
 990         needsep = 0;
 991         /* find set of paths that everybody touches */
 992         for (i = 0; i < num_parent; i++) {
 993                 /* show stat against the first parent even
 994                  * when doing combined diff.
 995                  */
 996                 int stat_opt = (opt->output_format &
 997                                 (DIFF_FORMAT_NUMSTAT|DIFF_FORMAT_DIFFSTAT));
 998                 if (i == 0 && stat_opt)
 999                         diffopts.output_format = stat_opt;
1000                 else
1001                         diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
1002                 diff_tree_sha1(parent[i], sha1, "", &diffopts);
1003                 diffcore_std(&diffopts);
1004                 paths = intersect_paths(paths, i, num_parent);
1005
1006                 if (show_log_first && i == 0) {
1007                         show_log(rev);
1008                         if (rev->verbose_header && opt->output_format)
1009                                 putchar(opt->line_termination);
1010                 }
1011                 diff_flush(&diffopts);
1012         }
1013
1014         /* find out surviving paths */
1015         for (num_paths = 0, p = paths; p; p = p->next) {
1016                 if (p->len)
1017                         num_paths++;
1018         }
1019         if (num_paths) {
1020                 if (opt->output_format & (DIFF_FORMAT_RAW |
1021                                           DIFF_FORMAT_NAME |
1022                                           DIFF_FORMAT_NAME_STATUS)) {
1023                         for (p = paths; p; p = p->next) {
1024                                 if (p->len)
1025                                         show_raw_diff(p, num_parent, rev);
1026                         }
1027                         needsep = 1;
1028                 }
1029                 else if (opt->output_format &
1030                          (DIFF_FORMAT_NUMSTAT|DIFF_FORMAT_DIFFSTAT))
1031                         needsep = 1;
1032                 if (opt->output_format & DIFF_FORMAT_PATCH) {
1033                         if (needsep)
1034                                 putchar(opt->line_termination);
1035                         for (p = paths; p; p = p->next) {
1036                                 if (p->len)
1037                                         show_patch_diff(p, num_parent, dense,
1038                                                         rev);
1039                         }
1040                 }
1041         }
1042
1043         /* Clean things up */
1044         while (paths) {
1045                 struct combine_diff_path *tmp = paths;
1046                 paths = paths->next;
1047                 free(tmp);
1048         }
1049 }
1050
1051 void diff_tree_combined_merge(const unsigned char *sha1,
1052                              int dense, struct rev_info *rev)
1053 {
1054         int num_parent;
1055         const unsigned char (*parent)[20];
1056         struct commit *commit = lookup_commit(sha1);
1057         struct commit_list *parents;
1058
1059         /* count parents */
1060         for (parents = commit->parents, num_parent = 0;
1061              parents;
1062              parents = parents->next, num_parent++)
1063                 ; /* nothing */
1064
1065         parent = xmalloc(num_parent * sizeof(*parent));
1066         for (parents = commit->parents, num_parent = 0;
1067              parents;
1068              parents = parents->next, num_parent++)
1069                 hashcpy((unsigned char *)(parent + num_parent),
1070                         parents->item->object.sha1);
1071         diff_tree_combined(sha1, parent, num_parent, dense, rev);
1072 }