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         xdemitcb_t ecb;
 215         struct combine_diff_state state;
 216         unsigned long sz;
 217
 218         if (result_deleted)
 219                 return; /* result deleted */
 220
 221         parent_file.ptr = grab_blob(parent, mode, &sz);
 222         parent_file.size = sz;
 223         memset(&xpp, 0, sizeof(xpp));
 224         xpp.flags = XDF_NEED_MINIMAL;
 225         memset(&xecfg, 0, sizeof(xecfg));
 226         memset(&state, 0, sizeof(state));
 227         state.nmask = nmask;
 228         state.sline = sline;
 229         state.lno = 1;
 230         state.num_parent = num_parent;
 231         state.n = n;
 232
 233         xdi_diff_outf(&parent_file, result_file, consume_line, &state,
 234                       &xpp, &xecfg, &ecb);
 235         free(parent_file.ptr);
 236
 237         /* Assign line numbers for this parent.
 238          *
 239          * sline[lno].p_lno[n] records the first line number
 240          * (counting from 1) for parent N if the final hunk display
 241          * started by showing sline[lno] (possibly showing the lost
 242          * lines attached to it first).
 243          */
 244         for (lno = 0,  p_lno = 1; lno <= cnt; lno++) {
 245                 struct lline *ll;
 246                 sline[lno].p_lno[n] = p_lno;
 247
 248                 /* How many lines would this sline advance the p_lno? */
 249                 ll = sline[lno].lost_head;
 250                 while (ll) {
 251                         if (ll->parent_map & nmask)
 252                                 p_lno++; /* '-' means parent had it */
 253                         ll = ll->next;
 254                 }
 255                 if (lno < cnt && !(sline[lno].flag & nmask))
 256                         p_lno++; /* no '+' means parent had it */
 257         }
 258         sline[lno].p_lno[n] = p_lno; /* trailer */
 259 }
 260
 261 static unsigned long context = 3;
 262 static char combine_marker = '@';
 263
 264 static int interesting(struct sline *sline, unsigned long all_mask)
 265 {
 266         /* If some parents lost lines here, or if we have added to
 267          * some parent, it is interesting.
 268          */
 269         return ((sline->flag & all_mask) || sline->lost_head);
 270 }
 271
 272 static unsigned long adjust_hunk_tail(struct sline *sline,
 273                                       unsigned long all_mask,
 274                                       unsigned long hunk_begin,
 275                                       unsigned long i)
 276 {
 277         /* i points at the first uninteresting line.  If the last line
 278          * of the hunk was interesting only because it has some
 279          * deletion, then it is not all that interesting for the
 280          * purpose of giving trailing context lines.  This is because
 281          * we output '-' line and then unmodified sline[i-1] itself in
 282          * that case which gives us one extra context line.
 283          */
 284         if ((hunk_begin + 1 <= i) && !(sline[i-1].flag & all_mask))
 285                 i--;
 286         return i;
 287 }
 288
 289 static unsigned long find_next(struct sline *sline,
 290                                unsigned long mark,
 291                                unsigned long i,
 292                                unsigned long cnt,
 293                                int look_for_uninteresting)
 294 {
 295         /* We have examined up to i-1 and are about to look at i.
 296          * Find next interesting or uninteresting line.  Here,
 297          * "interesting" does not mean interesting(), but marked by
 298          * the give_context() function below (i.e. it includes context
 299          * lines that are not interesting to interesting() function
 300          * that are surrounded by interesting() ones.
 301          */
 302         while (i <= cnt)
 303                 if (look_for_uninteresting
 304                     ? !(sline[i].flag & mark)
 305                     : (sline[i].flag & mark))
 306                         return i;
 307                 else
 308                         i++;
 309         return i;
 310 }
 311
 312 static int give_context(struct sline *sline, unsigned long cnt, int num_parent)
 313 {
 314         unsigned long all_mask = (1UL<<num_parent) - 1;
 315         unsigned long mark = (1UL<<num_parent);
 316         unsigned long no_pre_delete = (2UL<<num_parent);
 317         unsigned long i;
 318
 319         /* Two groups of interesting lines may have a short gap of
 320          * uninteresting lines.  Connect such groups to give them a
 321          * bit of context.
 322          *
 323          * We first start from what the interesting() function says,
 324          * and mark them with "mark", and paint context lines with the
 325          * mark.  So interesting() would still say false for such context
 326          * lines but they are treated as "interesting" in the end.
 327          */
 328         i = find_next(sline, mark, 0, cnt, 0);
 329         if (cnt < i)
 330                 return 0;
 331
 332         while (i <= cnt) {
 333                 unsigned long j = (context < i) ? (i - context) : 0;
 334                 unsigned long k;
 335
 336                 /* Paint a few lines before the first interesting line. */
 337                 while (j < i)
 338                         sline[j++].flag |= mark | no_pre_delete;
 339
 340         again:
 341                 /* we know up to i is to be included.  where does the
 342                  * next uninteresting one start?
 343                  */
 344                 j = find_next(sline, mark, i, cnt, 1);
 345                 if (cnt < j)
 346                         break; /* the rest are all interesting */
 347
 348                 /* lookahead context lines */
 349                 k = find_next(sline, mark, j, cnt, 0);
 350                 j = adjust_hunk_tail(sline, all_mask, i, j);
 351
 352                 if (k < j + context) {
 353                         /* k is interesting and [j,k) are not, but
 354                          * paint them interesting because the gap is small.
 355                          */
 356                         while (j < k)
 357                                 sline[j++].flag |= mark;
 358                         i = k;
 359                         goto again;
 360                 }
 361
 362                 /* j is the first uninteresting line and there is
 363                  * no overlap beyond it within context lines.  Paint
 364                  * the trailing edge a bit.
 365                  */
 366                 i = k;
 367                 k = (j + context < cnt+1) ? j + context : cnt+1;
 368                 while (j < k)
 369                         sline[j++].flag |= mark;
 370         }
 371         return 1;
 372 }
 373
 374 static int make_hunks(struct sline *sline, unsigned long cnt,
 375                        int num_parent, int dense)
 376 {
 377         unsigned long all_mask = (1UL<<num_parent) - 1;
 378         unsigned long mark = (1UL<<num_parent);
 379         unsigned long i;
 380         int has_interesting = 0;
 381
 382         for (i = 0; i <= cnt; i++) {
 383                 if (interesting(&sline[i], all_mask))
 384                         sline[i].flag |= mark;
 385                 else
 386                         sline[i].flag &= ~mark;
 387         }
 388         if (!dense)
 389                 return give_context(sline, cnt, num_parent);
 390
 391         /* Look at each hunk, and if we have changes from only one
 392          * parent, or the changes are the same from all but one
 393          * parent, mark that uninteresting.
 394          */
 395         i = 0;
 396         while (i <= cnt) {
 397                 unsigned long j, hunk_begin, hunk_end;
 398                 unsigned long same_diff;
 399                 while (i <= cnt && !(sline[i].flag & mark))
 400                         i++;
 401                 if (cnt < i)
 402                         break; /* No more interesting hunks */
 403                 hunk_begin = i;
 404                 for (j = i + 1; j <= cnt; j++) {
 405                         if (!(sline[j].flag & mark)) {
 406                                 /* Look beyond the end to see if there
 407                                  * is an interesting line after this
 408                                  * hunk within context span.
 409                                  */
 410                                 unsigned long la; /* lookahead */
 411                                 int contin = 0;
 412                                 la = adjust_hunk_tail(sline, all_mask,
 413                                                      hunk_begin, j);
 414                                 la = (la + context < cnt + 1) ?
 415                                         (la + context) : cnt + 1;
 416                                 while (j <= --la) {
 417                                         if (sline[la].flag & mark) {
 418                                                 contin = 1;
 419                                                 break;
 420                                         }
 421                                 }
 422                                 if (!contin)
 423                                         break;
 424                                 j = la;
 425                         }
 426                 }
 427                 hunk_end = j;
 428
 429                 /* [i..hunk_end) are interesting.  Now is it really
 430                  * interesting?  We check if there are only two versions
 431                  * and the result matches one of them.  That is, we look
 432                  * at:
 433                  *   (+) line, which records lines added to which parents;
 434                  *       this line appears in the result.
 435                  *   (-) line, which records from what parents the line
 436                  *       was removed; this line does not appear in the result.
 437                  * then check the set of parents the result has difference
 438                  * from, from all lines.  If there are lines that has
 439                  * different set of parents that the result has differences
 440                  * from, that means we have more than two versions.
 441                  *
 442                  * Even when we have only two versions, if the result does
 443                  * not match any of the parents, the it should be considered
 444                  * interesting.  In such a case, we would have all '+' line.
 445                  * After passing the above "two versions" test, that would
 446                  * appear as "the same set of parents" to be "all parents".
 447                  */
 448                 same_diff = 0;
 449                 has_interesting = 0;
 450                 for (j = i; j < hunk_end && !has_interesting; j++) {
 451                         unsigned long this_diff = sline[j].flag & all_mask;
 452                         struct lline *ll = sline[j].lost_head;
 453                         if (this_diff) {
 454                                 /* This has some changes.  Is it the
 455                                  * same as others?
 456                                  */
 457                                 if (!same_diff)
 458                                         same_diff = this_diff;
 459                                 else if (same_diff != this_diff) {
 460                                         has_interesting = 1;
 461                                         break;
 462                                 }
 463                         }
 464                         while (ll && !has_interesting) {
 465                                 /* Lost this line from these parents;
 466                                  * who are they?  Are they the same?
 467                                  */
 468                                 this_diff = ll->parent_map;
 469                                 if (!same_diff)
 470                                         same_diff = this_diff;
 471                                 else if (same_diff != this_diff) {
 472                                         has_interesting = 1;
 473                                 }
 474                                 ll = ll->next;
 475                         }
 476                 }
 477
 478                 if (!has_interesting && same_diff != all_mask) {
 479                         /* This hunk is not that interesting after all */
 480                         for (j = hunk_begin; j < hunk_end; j++)
 481                                 sline[j].flag &= ~mark;
 482                 }
 483                 i = hunk_end;
 484         }
 485
 486         has_interesting = give_context(sline, cnt, num_parent);
 487         return has_interesting;
 488 }
 489
 490 static void show_parent_lno(struct sline *sline, unsigned long l0, unsigned long l1, int n, unsigned long null_context)
 491 {
 492         l0 = sline[l0].p_lno[n];
 493         l1 = sline[l1].p_lno[n];
 494         printf(" -%lu,%lu", l0, l1-l0-null_context);
 495 }
 496
 497 static int hunk_comment_line(const char *bol)
 498 {
 499         int ch;
 500
 501         if (!bol)
 502                 return 0;
 503         ch = *bol & 0xff;
 504         return (isalpha(ch) || ch == '_' || ch == '$');
 505 }
 506
 507 static void show_line_to_eol(const char *line, int len, const char *reset)
 508 {
 509         int saw_cr_at_eol = 0;
 510         if (len < 0)
 511                 len = strlen(line);
 512         saw_cr_at_eol = (len && line[len-1] == '\r');
 513
 514         printf("%.*s%s%s\n", len - saw_cr_at_eol, line,
 515                reset,
 516                saw_cr_at_eol ? "\r" : "");
 517 }
 518
 519 static void dump_sline(struct sline *sline, unsigned long cnt, int num_parent,
 520                        int use_color, int result_deleted)
 521 {
 522         unsigned long mark = (1UL<<num_parent);
 523         unsigned long no_pre_delete = (2UL<<num_parent);
 524         int i;
 525         unsigned long lno = 0;
 526         const char *c_frag = diff_get_color(use_color, DIFF_FRAGINFO);
 527         const char *c_func = diff_get_color(use_color, DIFF_FUNCINFO);
 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 (result_deleted)
 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                                 printf("%s%s %s%s", c_reset,
 593                                                     c_plain, c_reset,
 594                                                     c_func);
 595                         for (i = 0; i < comment_end; i++)
 596                                 putchar(hunk_comment[i]);
 597                 }
 598
 599                 printf("%s\n", c_reset);
 600                 while (lno < hunk_end) {
 601                         struct lline *ll;
 602                         int j;
 603                         unsigned long p_mask;
 604                         struct sline *sl = &sline[lno++];
 605                         ll = (sl->flag & no_pre_delete) ? NULL : sl->lost_head;
 606                         while (ll) {
 607                                 fputs(c_old, stdout);
 608                                 for (j = 0; j < num_parent; j++) {
 609                                         if (ll->parent_map & (1UL<<j))
 610                                                 putchar('-');
 611                                         else
 612                                                 putchar(' ');
 613                                 }
 614                                 show_line_to_eol(ll->line, -1, c_reset);
 615                                 ll = ll->next;
 616                         }
 617                         if (cnt < lno)
 618                                 break;
 619                         p_mask = 1;
 620                         if (!(sl->flag & (mark-1))) {
 621                                 /*
 622                                  * This sline was here to hang the
 623                                  * lost lines in front of it.
 624                                  */
 625                                 if (!context)
 626                                         continue;
 627                                 fputs(c_plain, stdout);
 628                         }
 629                         else
 630                                 fputs(c_new, stdout);
 631                         for (j = 0; j < num_parent; j++) {
 632                                 if (p_mask & sl->flag)
 633                                         putchar('+');
 634                                 else
 635                                         putchar(' ');
 636                                 p_mask <<= 1;
 637                         }
 638                         show_line_to_eol(sl->bol, sl->len, c_reset);
 639                 }
 640         }
 641 }
 642
 643 static void reuse_combine_diff(struct sline *sline, unsigned long cnt,
 644                                int i, int j)
 645 {
 646         /* We have already examined parent j and we know parent i
 647          * and parent j are the same, so reuse the combined result
 648          * of parent j for parent i.
 649          */
 650         unsigned long lno, imask, jmask;
 651         imask = (1UL<<i);
 652         jmask = (1UL<<j);
 653
 654         for (lno = 0; lno <= cnt; lno++) {
 655                 struct lline *ll = sline->lost_head;
 656                 sline->p_lno[i] = sline->p_lno[j];
 657                 while (ll) {
 658                         if (ll->parent_map & jmask)
 659                                 ll->parent_map |= imask;
 660                         ll = ll->next;
 661                 }
 662                 if (sline->flag & jmask)
 663                         sline->flag |= imask;
 664                 sline++;
 665         }
 666         /* the overall size of the file (sline[cnt]) */
 667         sline->p_lno[i] = sline->p_lno[j];
 668 }
 669
 670 static void dump_quoted_path(const char *head,
 671                              const char *prefix,
 672                              const char *path,
 673                              const char *c_meta, const char *c_reset)
 674 {
 675         static struct strbuf buf = STRBUF_INIT;
 676
 677         strbuf_reset(&buf);
 678         strbuf_addstr(&buf, c_meta);
 679         strbuf_addstr(&buf, head);
 680         quote_two_c_style(&buf, prefix, path, 0);
 681         strbuf_addstr(&buf, c_reset);
 682         puts(buf.buf);
 683 }
 684
 685 static void show_patch_diff(struct combine_diff_path *elem, int num_parent,
 686                             int dense, struct rev_info *rev)
 687 {
 688         struct diff_options *opt = &rev->diffopt;
 689         unsigned long result_size, cnt, lno;
 690         int result_deleted = 0;
 691         char *result, *cp;
 692         struct sline *sline; /* survived lines */
 693         int mode_differs = 0;
 694         int i, show_hunks;
 695         int working_tree_file = is_null_sha1(elem->sha1);
 696         int abbrev = DIFF_OPT_TST(opt, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
 697         const char *a_prefix, *b_prefix;
 698         mmfile_t result_file;
 699
 700         context = opt->context;
 701         a_prefix = opt->a_prefix ? opt->a_prefix : "a/";
 702         b_prefix = opt->b_prefix ? opt->b_prefix : "b/";
 703
 704         /* Read the result of merge first */
 705         if (!working_tree_file)
 706                 result = grab_blob(elem->sha1, elem->mode, &result_size);
 707         else {
 708                 /* Used by diff-tree to read from the working tree */
 709                 struct stat st;
 710                 int fd = -1;
 711
 712                 if (lstat(elem->path, &st) < 0)
 713                         goto deleted_file;
 714
 715                 if (S_ISLNK(st.st_mode)) {
 716                         struct strbuf buf = STRBUF_INIT;
 717
 718                         if (strbuf_readlink(&buf, elem->path, st.st_size) < 0) {
 719                                 error("readlink(%s): %s", elem->path,
 720                                       strerror(errno));
 721                                 return;
 722                         }
 723                         result_size = buf.len;
 724                         result = strbuf_detach(&buf, NULL);
 725                         elem->mode = canon_mode(st.st_mode);
 726                 } else if (S_ISDIR(st.st_mode)) {
 727                         unsigned char sha1[20];
 728                         if (resolve_gitlink_ref(elem->path, "HEAD", sha1) < 0)
 729                                 result = grab_blob(elem->sha1, elem->mode, &result_size);
 730                         else
 731                                 result = grab_blob(sha1, elem->mode, &result_size);
 732                 } else if (0 <= (fd = open(elem->path, O_RDONLY))) {
 733                         size_t len = xsize_t(st.st_size);
 734                         ssize_t done;
 735                         int is_file, i;
 736
 737                         elem->mode = canon_mode(st.st_mode);
 738                         /* if symlinks don't work, assume symlink if all parents
 739                          * are symlinks
 740                          */
 741                         is_file = has_symlinks;
 742                         for (i = 0; !is_file && i < num_parent; i++)
 743                                 is_file = !S_ISLNK(elem->parent[i].mode);
 744                         if (!is_file)
 745                                 elem->mode = canon_mode(S_IFLNK);
 746
 747                         result_size = len;
 748                         result = xmalloc(len + 1);
 749
 750                         done = read_in_full(fd, result, len);
 751                         if (done < 0)
 752                                 die_errno("read error '%s'", elem->path);
 753                         else if (done < len)
 754                                 die("early EOF '%s'", elem->path);
 755
 756                         result[len] = 0;
 757
 758                         /* If not a fake symlink, apply filters, e.g. autocrlf */
 759                         if (is_file) {
 760                                 struct strbuf buf = STRBUF_INIT;
 761
 762                                 if (convert_to_git(elem->path, result, len, &buf, safe_crlf)) {
 763                                         free(result);
 764                                         result = strbuf_detach(&buf, &len);
 765                                         result_size = len;
 766                                 }
 767                         }
 768                 }
 769                 else {
 770                 deleted_file:
 771                         result_deleted = 1;
 772                         result_size = 0;
 773                         elem->mode = 0;
 774                         result = xcalloc(1, 1);
 775                 }
 776
 777                 if (0 <= fd)
 778                         close(fd);
 779         }
 780
 781         for (cnt = 0, cp = result; cp < result + result_size; cp++) {
 782                 if (*cp == '\n')
 783                         cnt++;
 784         }
 785         if (result_size && result[result_size-1] != '\n')
 786                 cnt++; /* incomplete line */
 787
 788         sline = xcalloc(cnt+2, sizeof(*sline));
 789         sline[0].bol = result;
 790         for (lno = 0; lno <= cnt + 1; lno++) {
 791                 sline[lno].lost_tail = &sline[lno].lost_head;
 792                 sline[lno].flag = 0;
 793         }
 794         for (lno = 0, cp = result; cp < result + result_size; cp++) {
 795                 if (*cp == '\n') {
 796                         sline[lno].len = cp - sline[lno].bol;
 797                         lno++;
 798                         if (lno < cnt)
 799                                 sline[lno].bol = cp + 1;
 800                 }
 801         }
 802         if (result_size && result[result_size-1] != '\n')
 803                 sline[cnt-1].len = result_size - (sline[cnt-1].bol - result);
 804
 805         result_file.ptr = result;
 806         result_file.size = result_size;
 807
 808         /* Even p_lno[cnt+1] is valid -- that is for the end line number
 809          * for deletion hunk at the end.
 810          */
 811         sline[0].p_lno = xcalloc((cnt+2) * num_parent, sizeof(unsigned long));
 812         for (lno = 0; lno <= cnt; lno++)
 813                 sline[lno+1].p_lno = sline[lno].p_lno + num_parent;
 814
 815         for (i = 0; i < num_parent; i++) {
 816                 int j;
 817                 for (j = 0; j < i; j++) {
 818                         if (!hashcmp(elem->parent[i].sha1,
 819                                      elem->parent[j].sha1)) {
 820                                 reuse_combine_diff(sline, cnt, i, j);
 821                                 break;
 822                         }
 823                 }
 824                 if (i <= j)
 825                         combine_diff(elem->parent[i].sha1,
 826                                      elem->parent[i].mode,
 827                                      &result_file, sline,
 828                                      cnt, i, num_parent, result_deleted);
 829                 if (elem->parent[i].mode != elem->mode)
 830                         mode_differs = 1;
 831         }
 832
 833         show_hunks = make_hunks(sline, cnt, num_parent, dense);
 834
 835         if (show_hunks || mode_differs || working_tree_file) {
 836                 const char *abb;
 837                 int use_color = DIFF_OPT_TST(opt, COLOR_DIFF);
 838                 const char *c_meta = diff_get_color(use_color, DIFF_METAINFO);
 839                 const char *c_reset = diff_get_color(use_color, DIFF_RESET);
 840                 int added = 0;
 841                 int deleted = 0;
 842
 843                 if (rev->loginfo && !rev->no_commit_id)
 844                         show_log(rev);
 845                 dump_quoted_path(dense ? "diff --cc " : "diff --combined ",
 846                                  "", elem->path, c_meta, c_reset);
 847                 printf("%sindex ", c_meta);
 848                 for (i = 0; i < num_parent; i++) {
 849                         abb = find_unique_abbrev(elem->parent[i].sha1,
 850                                                  abbrev);
 851                         printf("%s%s", i ? "," : "", abb);
 852                 }
 853                 abb = find_unique_abbrev(elem->sha1, abbrev);
 854                 printf("..%s%s\n", abb, c_reset);
 855
 856                 if (mode_differs) {
 857                         deleted = !elem->mode;
 858
 859                         /* We say it was added if nobody had it */
 860                         added = !deleted;
 861                         for (i = 0; added && i < num_parent; i++)
 862                                 if (elem->parent[i].status !=
 863                                     DIFF_STATUS_ADDED)
 864                                         added = 0;
 865                         if (added)
 866                                 printf("%snew file mode %06o",
 867                                        c_meta, elem->mode);
 868                         else {
 869                                 if (deleted)
 870                                         printf("%sdeleted file ", c_meta);
 871                                 printf("mode ");
 872                                 for (i = 0; i < num_parent; i++) {
 873                                         printf("%s%06o", i ? "," : "",
 874                                                elem->parent[i].mode);
 875                                 }
 876                                 if (elem->mode)
 877                                         printf("..%06o", elem->mode);
 878                         }
 879                         printf("%s\n", c_reset);
 880                 }
 881                 if (added)
 882                         dump_quoted_path("--- ", "", "/dev/null",
 883                                          c_meta, c_reset);
 884                 else
 885                         dump_quoted_path("--- ", a_prefix, elem->path,
 886                                          c_meta, c_reset);
 887                 if (deleted)
 888                         dump_quoted_path("+++ ", "", "/dev/null",
 889                                          c_meta, c_reset);
 890                 else
 891                         dump_quoted_path("+++ ", b_prefix, elem->path,
 892                                          c_meta, c_reset);
 893                 dump_sline(sline, cnt, num_parent,
 894                            DIFF_OPT_TST(opt, COLOR_DIFF), result_deleted);
 895         }
 896         free(result);
 897
 898         for (lno = 0; lno < cnt; lno++) {
 899                 if (sline[lno].lost_head) {
 900                         struct lline *ll = sline[lno].lost_head;
 901                         while (ll) {
 902                                 struct lline *tmp = ll;
 903                                 ll = ll->next;
 904                                 free(tmp);
 905                         }
 906                 }
 907         }
 908         free(sline[0].p_lno);
 909         free(sline);
 910 }
 911
 912 #define COLONS "::::::::::::::::::::::::::::::::"
 913
 914 static void show_raw_diff(struct combine_diff_path *p, int num_parent, struct rev_info *rev)
 915 {
 916         struct diff_options *opt = &rev->diffopt;
 917         int i, offset;
 918         const char *prefix;
 919         int line_termination, inter_name_termination;
 920
 921         line_termination = opt->line_termination;
 922         inter_name_termination = '\t';
 923         if (!line_termination)
 924                 inter_name_termination = 0;
 925
 926         if (rev->loginfo && !rev->no_commit_id)
 927                 show_log(rev);
 928
 929         if (opt->output_format & DIFF_FORMAT_RAW) {
 930                 offset = strlen(COLONS) - num_parent;
 931                 if (offset < 0)
 932                         offset = 0;
 933                 prefix = COLONS + offset;
 934
 935                 /* Show the modes */
 936                 for (i = 0; i < num_parent; i++) {
 937                         printf("%s%06o", prefix, p->parent[i].mode);
 938                         prefix = " ";
 939                 }
 940                 printf("%s%06o", prefix, p->mode);
 941
 942                 /* Show sha1's */
 943                 for (i = 0; i < num_parent; i++)
 944                         printf(" %s", diff_unique_abbrev(p->parent[i].sha1,
 945                                                          opt->abbrev));
 946                 printf(" %s ", diff_unique_abbrev(p->sha1, opt->abbrev));
 947         }
 948
 949         if (opt->output_format & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS)) {
 950                 for (i = 0; i < num_parent; i++)
 951                         putchar(p->parent[i].status);
 952                 putchar(inter_name_termination);
 953         }
 954
 955         write_name_quoted(p->path, stdout, line_termination);
 956 }
 957
 958 void show_combined_diff(struct combine_diff_path *p,
 959                        int num_parent,
 960                        int dense,
 961                        struct rev_info *rev)
 962 {
 963         struct diff_options *opt = &rev->diffopt;
 964         if (!p->len)
 965                 return;
 966         if (opt->output_format & (DIFF_FORMAT_RAW |
 967                                   DIFF_FORMAT_NAME |
 968                                   DIFF_FORMAT_NAME_STATUS))
 969                 show_raw_diff(p, num_parent, rev);
 970         else if (opt->output_format & DIFF_FORMAT_PATCH)
 971                 show_patch_diff(p, num_parent, dense, rev);
 972 }
 973
 974 void diff_tree_combined(const unsigned char *sha1,
 975                         const unsigned char parent[][20],
 976                         int num_parent,
 977                         int dense,
 978                         struct rev_info *rev)
 979 {
 980         struct diff_options *opt = &rev->diffopt;
 981         struct diff_options diffopts;
 982         struct combine_diff_path *p, *paths = NULL;
 983         int i, num_paths, needsep, show_log_first;
 984
 985         diffopts = *opt;
 986         diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
 987         DIFF_OPT_SET(&diffopts, RECURSIVE);
 988         DIFF_OPT_CLR(&diffopts, ALLOW_EXTERNAL);
 989
 990         show_log_first = !!rev->loginfo && !rev->no_commit_id;
 991         needsep = 0;
 992         /* find set of paths that everybody touches */
 993         for (i = 0; i < num_parent; i++) {
 994                 /* show stat against the first parent even
 995                  * when doing combined diff.
 996                  */
 997                 int stat_opt = (opt->output_format &
 998                                 (DIFF_FORMAT_NUMSTAT|DIFF_FORMAT_DIFFSTAT));
 999                 if (i == 0 && stat_opt)
1000                         diffopts.output_format = stat_opt;
1001                 else
1002                         diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
1003                 diff_tree_sha1(parent[i], sha1, "", &diffopts);
1004                 diffcore_std(&diffopts);
1005                 paths = intersect_paths(paths, i, num_parent);
1006
1007                 if (show_log_first && i == 0) {
1008                         show_log(rev);
1009                         if (rev->verbose_header && opt->output_format)
1010                                 putchar(opt->line_termination);
1011                 }
1012                 diff_flush(&diffopts);
1013         }
1014
1015         /* find out surviving paths */
1016         for (num_paths = 0, p = paths; p; p = p->next) {
1017                 if (p->len)
1018                         num_paths++;
1019         }
1020         if (num_paths) {
1021                 if (opt->output_format & (DIFF_FORMAT_RAW |
1022                                           DIFF_FORMAT_NAME |
1023                                           DIFF_FORMAT_NAME_STATUS)) {
1024                         for (p = paths; p; p = p->next) {
1025                                 if (p->len)
1026                                         show_raw_diff(p, num_parent, rev);
1027                         }
1028                         needsep = 1;
1029                 }
1030                 else if (opt->output_format &
1031                          (DIFF_FORMAT_NUMSTAT|DIFF_FORMAT_DIFFSTAT))
1032                         needsep = 1;
1033                 if (opt->output_format & DIFF_FORMAT_PATCH) {
1034                         if (needsep)
1035                                 putchar(opt->line_termination);
1036                         for (p = paths; p; p = p->next) {
1037                                 if (p->len)
1038                                         show_patch_diff(p, num_parent, dense,
1039                                                         rev);
1040                         }
1041                 }
1042         }
1043
1044         /* Clean things up */
1045         while (paths) {
1046                 struct combine_diff_path *tmp = paths;
1047                 paths = paths->next;
1048                 free(tmp);
1049         }
1050 }
1051
1052 void diff_tree_combined_merge(const unsigned char *sha1,
1053                              int dense, struct rev_info *rev)
1054 {
1055         int num_parent;
1056         const unsigned char (*parent)[20];
1057         struct commit *commit = lookup_commit(sha1);
1058         struct commit_list *parents;
1059
1060         /* count parents */
1061         for (parents = commit->parents, num_parent = 0;
1062              parents;
1063              parents = parents->next, num_parent++)
1064                 ; /* nothing */
1065
1066         parent = xmalloc(num_parent * sizeof(*parent));
1067         for (parents = commit->parents, num_parent = 0;
1068              parents;
1069              parents = parents->next, num_parent++)
1070                 hashcpy((unsigned char *)(parent + num_parent),
1071                         parents->item->object.sha1);
1072         diff_tree_combined(sha1, parent, num_parent, dense, rev);
1073 }