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 #include "userdiff.h"
  11
  12 static struct combine_diff_path *intersect_paths(struct combine_diff_path *curr, int n, int num_parent)
  13 {
  14         struct diff_queue_struct *q = &diff_queued_diff;
  15         struct combine_diff_path *p;
  16         int i;
  17
  18         if (!n) {
  19                 struct combine_diff_path *list = NULL, **tail = &list;
  20                 for (i = 0; i < q->nr; i++) {
  21                         int len;
  22                         const char *path;
  23                         if (diff_unmodified_pair(q->queue[i]))
  24                                 continue;
  25                         path = q->queue[i]->two->path;
  26                         len = strlen(path);
  27                         p = xmalloc(combine_diff_path_size(num_parent, len));
  28                         p->path = (char *) &(p->parent[num_parent]);
  29                         memcpy(p->path, path, len);
  30                         p->path[len] = 0;
  31                         p->len = len;
  32                         p->next = NULL;
  33                         memset(p->parent, 0,
  34                                sizeof(p->parent[0]) * num_parent);
  35
  36                         hashcpy(p->sha1, q->queue[i]->two->sha1);
  37                         p->mode = q->queue[i]->two->mode;
  38                         hashcpy(p->parent[n].sha1, q->queue[i]->one->sha1);
  39                         p->parent[n].mode = q->queue[i]->one->mode;
  40                         p->parent[n].status = q->queue[i]->status;
  41                         *tail = p;
  42                         tail = &p->next;
  43                 }
  44                 return list;
  45         }
  46
  47         for (p = curr; p; p = p->next) {
  48                 int found = 0;
  49                 if (!p->len)
  50                         continue;
  51                 for (i = 0; i < q->nr; i++) {
  52                         const char *path;
  53                         int len;
  54
  55                         if (diff_unmodified_pair(q->queue[i]))
  56                                 continue;
  57                         path = q->queue[i]->two->path;
  58                         len = strlen(path);
  59                         if (len == p->len && !memcmp(path, p->path, len)) {
  60                                 found = 1;
  61                                 hashcpy(p->parent[n].sha1, q->queue[i]->one->sha1);
  62                                 p->parent[n].mode = q->queue[i]->one->mode;
  63                                 p->parent[n].status = q->queue[i]->status;
  64                                 break;
  65                         }
  66                 }
  67                 if (!found)
  68                         p->len = 0;
  69         }
  70         return curr;
  71 }
  72
  73 /* Lines lost from parent */
  74 struct lline {
  75         struct lline *next;
  76         int len;
  77         unsigned long parent_map;
  78         char line[FLEX_ARRAY];
  79 };
  80
  81 /* Lines surviving in the merge result */
  82 struct sline {
  83         struct lline *lost_head, **lost_tail;
  84         struct lline *next_lost;
  85         char *bol;
  86         int len;
  87         /* bit 0 up to (N-1) are on if the parent has this line (i.e.
  88          * we did not change it).
  89          * bit N is used for "interesting" lines, including context.
  90          * bit (N+1) is used for "do not show deletion before this".
  91          */
  92         unsigned long flag;
  93         unsigned long *p_lno;
  94 };
  95
  96 static char *grab_blob(const unsigned char *sha1, unsigned int mode, unsigned long *size)
  97 {
  98         char *blob;
  99         enum object_type type;
 100
 101         if (S_ISGITLINK(mode)) {
 102                 blob = xmalloc(100);
 103                 *size = snprintf(blob, 100,
 104                                  "Subproject commit %s\n", sha1_to_hex(sha1));
 105         } else if (is_null_sha1(sha1)) {
 106                 /* deleted blob */
 107                 *size = 0;
 108                 return xcalloc(1, 1);
 109         } else {
 110                 blob = read_sha1_file(sha1, &type, size);
 111                 if (type != OBJ_BLOB)
 112                         die("object '%s' is not a blob!", sha1_to_hex(sha1));
 113         }
 114         return blob;
 115 }
 116
 117 static void append_lost(struct sline *sline, int n, const char *line, int len)
 118 {
 119         struct lline *lline;
 120         unsigned long this_mask = (1UL<<n);
 121         if (line[len-1] == '\n')
 122                 len--;
 123
 124         /* Check to see if we can squash things */
 125         if (sline->lost_head) {
 126                 lline = sline->next_lost;
 127                 while (lline) {
 128                         if (lline->len == len &&
 129                             !memcmp(lline->line, line, len)) {
 130                                 lline->parent_map |= this_mask;
 131                                 sline->next_lost = lline->next;
 132                                 return;
 133                         }
 134                         lline = lline->next;
 135                 }
 136         }
 137
 138         lline = xmalloc(sizeof(*lline) + len + 1);
 139         lline->len = len;
 140         lline->next = NULL;
 141         lline->parent_map = this_mask;
 142         memcpy(lline->line, line, len);
 143         lline->line[len] = 0;
 144         *sline->lost_tail = lline;
 145         sline->lost_tail = &lline->next;
 146         sline->next_lost = NULL;
 147 }
 148
 149 struct combine_diff_state {
 150         unsigned int lno;
 151         int ob, on, nb, nn;
 152         unsigned long nmask;
 153         int num_parent;
 154         int n;
 155         struct sline *sline;
 156         struct sline *lost_bucket;
 157 };
 158
 159 static void consume_line(void *state_, char *line, unsigned long len)
 160 {
 161         struct combine_diff_state *state = state_;
 162         if (5 < len && !memcmp("@@ -", line, 4)) {
 163                 if (parse_hunk_header(line, len,
 164                                       &state->ob, &state->on,
 165                                       &state->nb, &state->nn))
 166                         return;
 167                 state->lno = state->nb;
 168                 if (state->nn == 0) {
 169                         /* @@ -X,Y +N,0 @@ removed Y lines
 170                          * that would have come *after* line N
 171                          * in the result.  Our lost buckets hang
 172                          * to the line after the removed lines,
 173                          *
 174                          * Note that this is correct even when N == 0,
 175                          * in which case the hunk removes the first
 176                          * line in the file.
 177                          */
 178                         state->lost_bucket = &state->sline[state->nb];
 179                         if (!state->nb)
 180                                 state->nb = 1;
 181                 } else {
 182                         state->lost_bucket = &state->sline[state->nb-1];
 183                 }
 184                 if (!state->sline[state->nb-1].p_lno)
 185                         state->sline[state->nb-1].p_lno =
 186                                 xcalloc(state->num_parent,
 187                                         sizeof(unsigned long));
 188                 state->sline[state->nb-1].p_lno[state->n] = state->ob;
 189                 state->lost_bucket->next_lost = state->lost_bucket->lost_head;
 190                 return;
 191         }
 192         if (!state->lost_bucket)
 193                 return; /* not in any hunk yet */
 194         switch (line[0]) {
 195         case '-':
 196                 append_lost(state->lost_bucket, state->n, line+1, len-1);
 197                 break;
 198         case '+':
 199                 state->sline[state->lno-1].flag |= state->nmask;
 200                 state->lno++;
 201                 break;
 202         }
 203 }
 204
 205 static void combine_diff(const unsigned char *parent, unsigned int mode,
 206                          mmfile_t *result_file,
 207                          struct sline *sline, unsigned int cnt, int n,
 208                          int num_parent, int result_deleted)
 209 {
 210         unsigned int p_lno, lno;
 211         unsigned long nmask = (1UL << n);
 212         xpparam_t xpp;
 213         xdemitconf_t xecfg;
 214         mmfile_t parent_file;
 215         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 = 0;
 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);
 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_combined_header(struct combine_diff_path *elem,
 686                                  int num_parent,
 687                                  int dense,
 688                                  struct rev_info *rev,
 689                                  int mode_differs,
 690                                  int show_file_header)
 691 {
 692         struct diff_options *opt = &rev->diffopt;
 693         int abbrev = DIFF_OPT_TST(opt, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
 694         const char *a_prefix = opt->a_prefix ? opt->a_prefix : "a/";
 695         const char *b_prefix = opt->b_prefix ? opt->b_prefix : "b/";
 696         int use_color = DIFF_OPT_TST(opt, COLOR_DIFF);
 697         const char *c_meta = diff_get_color(use_color, DIFF_METAINFO);
 698         const char *c_reset = diff_get_color(use_color, DIFF_RESET);
 699         const char *abb;
 700         int added = 0;
 701         int deleted = 0;
 702         int i;
 703
 704         if (rev->loginfo && !rev->no_commit_id)
 705                 show_log(rev);
 706
 707         dump_quoted_path(dense ? "diff --cc " : "diff --combined ",
 708                          "", elem->path, c_meta, c_reset);
 709         printf("%sindex ", c_meta);
 710         for (i = 0; i < num_parent; i++) {
 711                 abb = find_unique_abbrev(elem->parent[i].sha1,
 712                                          abbrev);
 713                 printf("%s%s", i ? "," : "", abb);
 714         }
 715         abb = find_unique_abbrev(elem->sha1, abbrev);
 716         printf("..%s%s\n", abb, c_reset);
 717
 718         if (mode_differs) {
 719                 deleted = !elem->mode;
 720
 721                 /* We say it was added if nobody had it */
 722                 added = !deleted;
 723                 for (i = 0; added && i < num_parent; i++)
 724                         if (elem->parent[i].status !=
 725                             DIFF_STATUS_ADDED)
 726                                 added = 0;
 727                 if (added)
 728                         printf("%snew file mode %06o",
 729                                c_meta, elem->mode);
 730                 else {
 731                         if (deleted)
 732                                 printf("%sdeleted file ", c_meta);
 733                         printf("mode ");
 734                         for (i = 0; i < num_parent; i++) {
 735                                 printf("%s%06o", i ? "," : "",
 736                                        elem->parent[i].mode);
 737                         }
 738                         if (elem->mode)
 739                                 printf("..%06o", elem->mode);
 740                 }
 741                 printf("%s\n", c_reset);
 742         }
 743
 744         if (!show_file_header)
 745                 return;
 746
 747         if (added)
 748                 dump_quoted_path("--- ", "", "/dev/null",
 749                                  c_meta, c_reset);
 750         else
 751                 dump_quoted_path("--- ", a_prefix, elem->path,
 752                                  c_meta, c_reset);
 753         if (deleted)
 754                 dump_quoted_path("+++ ", "", "/dev/null",
 755                                  c_meta, c_reset);
 756         else
 757                 dump_quoted_path("+++ ", b_prefix, elem->path,
 758                                  c_meta, c_reset);
 759 }
 760
 761 static void show_patch_diff(struct combine_diff_path *elem, int num_parent,
 762                             int dense, struct rev_info *rev)
 763 {
 764         struct diff_options *opt = &rev->diffopt;
 765         unsigned long result_size, cnt, lno;
 766         int result_deleted = 0;
 767         char *result, *cp;
 768         struct sline *sline; /* survived lines */
 769         int mode_differs = 0;
 770         int i, show_hunks;
 771         int working_tree_file = is_null_sha1(elem->sha1);
 772         mmfile_t result_file;
 773         struct userdiff_driver *userdiff;
 774         int is_binary;
 775
 776         context = opt->context;
 777         userdiff = userdiff_find_by_path(elem->path);
 778         if (!userdiff)
 779                 userdiff = userdiff_find_by_name("default");
 780
 781         /* Read the result of merge first */
 782         if (!working_tree_file)
 783                 result = grab_blob(elem->sha1, elem->mode, &result_size);
 784         else {
 785                 /* Used by diff-tree to read from the working tree */
 786                 struct stat st;
 787                 int fd = -1;
 788
 789                 if (lstat(elem->path, &st) < 0)
 790                         goto deleted_file;
 791
 792                 if (S_ISLNK(st.st_mode)) {
 793                         struct strbuf buf = STRBUF_INIT;
 794
 795                         if (strbuf_readlink(&buf, elem->path, st.st_size) < 0) {
 796                                 error("readlink(%s): %s", elem->path,
 797                                       strerror(errno));
 798                                 return;
 799                         }
 800                         result_size = buf.len;
 801                         result = strbuf_detach(&buf, NULL);
 802                         elem->mode = canon_mode(st.st_mode);
 803                 } else if (S_ISDIR(st.st_mode)) {
 804                         unsigned char sha1[20];
 805                         if (resolve_gitlink_ref(elem->path, "HEAD", sha1) < 0)
 806                                 result = grab_blob(elem->sha1, elem->mode, &result_size);
 807                         else
 808                                 result = grab_blob(sha1, elem->mode, &result_size);
 809                 } else if (0 <= (fd = open(elem->path, O_RDONLY))) {
 810                         size_t len = xsize_t(st.st_size);
 811                         ssize_t done;
 812                         int is_file, i;
 813
 814                         elem->mode = canon_mode(st.st_mode);
 815                         /* if symlinks don't work, assume symlink if all parents
 816                          * are symlinks
 817                          */
 818                         is_file = has_symlinks;
 819                         for (i = 0; !is_file && i < num_parent; i++)
 820                                 is_file = !S_ISLNK(elem->parent[i].mode);
 821                         if (!is_file)
 822                                 elem->mode = canon_mode(S_IFLNK);
 823
 824                         result_size = len;
 825                         result = xmalloc(len + 1);
 826
 827                         done = read_in_full(fd, result, len);
 828                         if (done < 0)
 829                                 die_errno("read error '%s'", elem->path);
 830                         else if (done < len)
 831                                 die("early EOF '%s'", elem->path);
 832
 833                         result[len] = 0;
 834
 835                         /* If not a fake symlink, apply filters, e.g. autocrlf */
 836                         if (is_file) {
 837                                 struct strbuf buf = STRBUF_INIT;
 838
 839                                 if (convert_to_git(elem->path, result, len, &buf, safe_crlf)) {
 840                                         free(result);
 841                                         result = strbuf_detach(&buf, &len);
 842                                         result_size = len;
 843                                 }
 844                         }
 845                 }
 846                 else {
 847                 deleted_file:
 848                         result_deleted = 1;
 849                         result_size = 0;
 850                         elem->mode = 0;
 851                         result = xcalloc(1, 1);
 852                 }
 853
 854                 if (0 <= fd)
 855                         close(fd);
 856         }
 857
 858         for (i = 0; i < num_parent; i++) {
 859                 if (elem->parent[i].mode != elem->mode) {
 860                         mode_differs = 1;
 861                         break;
 862                 }
 863         }
 864
 865         if (userdiff->binary != -1)
 866                 is_binary = userdiff->binary;
 867         else {
 868                 is_binary = buffer_is_binary(result, result_size);
 869                 for (i = 0; !is_binary && i < num_parent; i++) {
 870                         char *buf;
 871                         unsigned long size;
 872                         buf = grab_blob(elem->parent[i].sha1,
 873                                         elem->parent[i].mode,
 874                                         &size);
 875                         if (buffer_is_binary(buf, size))
 876                                 is_binary = 1;
 877                         free(buf);
 878                 }
 879         }
 880         if (is_binary) {
 881                 show_combined_header(elem, num_parent, dense, rev,
 882                                      mode_differs, 0);
 883                 printf("Binary files differ\n");
 884                 free(result);
 885                 return;
 886         }
 887
 888         for (cnt = 0, cp = result; cp < result + result_size; cp++) {
 889                 if (*cp == '\n')
 890                         cnt++;
 891         }
 892         if (result_size && result[result_size-1] != '\n')
 893                 cnt++; /* incomplete line */
 894
 895         sline = xcalloc(cnt+2, sizeof(*sline));
 896         sline[0].bol = result;
 897         for (lno = 0; lno <= cnt + 1; lno++) {
 898                 sline[lno].lost_tail = &sline[lno].lost_head;
 899                 sline[lno].flag = 0;
 900         }
 901         for (lno = 0, cp = result; cp < result + result_size; cp++) {
 902                 if (*cp == '\n') {
 903                         sline[lno].len = cp - sline[lno].bol;
 904                         lno++;
 905                         if (lno < cnt)
 906                                 sline[lno].bol = cp + 1;
 907                 }
 908         }
 909         if (result_size && result[result_size-1] != '\n')
 910                 sline[cnt-1].len = result_size - (sline[cnt-1].bol - result);
 911
 912         result_file.ptr = result;
 913         result_file.size = result_size;
 914
 915         /* Even p_lno[cnt+1] is valid -- that is for the end line number
 916          * for deletion hunk at the end.
 917          */
 918         sline[0].p_lno = xcalloc((cnt+2) * num_parent, sizeof(unsigned long));
 919         for (lno = 0; lno <= cnt; lno++)
 920                 sline[lno+1].p_lno = sline[lno].p_lno + num_parent;
 921
 922         for (i = 0; i < num_parent; i++) {
 923                 int j;
 924                 for (j = 0; j < i; j++) {
 925                         if (!hashcmp(elem->parent[i].sha1,
 926                                      elem->parent[j].sha1)) {
 927                                 reuse_combine_diff(sline, cnt, i, j);
 928                                 break;
 929                         }
 930                 }
 931                 if (i <= j)
 932                         combine_diff(elem->parent[i].sha1,
 933                                      elem->parent[i].mode,
 934                                      &result_file, sline,
 935                                      cnt, i, num_parent, result_deleted);
 936         }
 937
 938         show_hunks = make_hunks(sline, cnt, num_parent, dense);
 939
 940         if (show_hunks || mode_differs || working_tree_file) {
 941                 show_combined_header(elem, num_parent, dense, rev,
 942                                      mode_differs, 1);
 943                 dump_sline(sline, cnt, num_parent,
 944                            DIFF_OPT_TST(opt, COLOR_DIFF), result_deleted);
 945         }
 946         free(result);
 947
 948         for (lno = 0; lno < cnt; lno++) {
 949                 if (sline[lno].lost_head) {
 950                         struct lline *ll = sline[lno].lost_head;
 951                         while (ll) {
 952                                 struct lline *tmp = ll;
 953                                 ll = ll->next;
 954                                 free(tmp);
 955                         }
 956                 }
 957         }
 958         free(sline[0].p_lno);
 959         free(sline);
 960 }
 961
 962 #define COLONS "::::::::::::::::::::::::::::::::"
 963
 964 static void show_raw_diff(struct combine_diff_path *p, int num_parent, struct rev_info *rev)
 965 {
 966         struct diff_options *opt = &rev->diffopt;
 967         int i, offset;
 968         const char *prefix;
 969         int line_termination, inter_name_termination;
 970
 971         line_termination = opt->line_termination;
 972         inter_name_termination = '\t';
 973         if (!line_termination)
 974                 inter_name_termination = 0;
 975
 976         if (rev->loginfo && !rev->no_commit_id)
 977                 show_log(rev);
 978
 979         if (opt->output_format & DIFF_FORMAT_RAW) {
 980                 offset = strlen(COLONS) - num_parent;
 981                 if (offset < 0)
 982                         offset = 0;
 983                 prefix = COLONS + offset;
 984
 985                 /* Show the modes */
 986                 for (i = 0; i < num_parent; i++) {
 987                         printf("%s%06o", prefix, p->parent[i].mode);
 988                         prefix = " ";
 989                 }
 990                 printf("%s%06o", prefix, p->mode);
 991
 992                 /* Show sha1's */
 993                 for (i = 0; i < num_parent; i++)
 994                         printf(" %s", diff_unique_abbrev(p->parent[i].sha1,
 995                                                          opt->abbrev));
 996                 printf(" %s ", diff_unique_abbrev(p->sha1, opt->abbrev));
 997         }
 998
 999         if (opt->output_format & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS)) {
1000                 for (i = 0; i < num_parent; i++)
1001                         putchar(p->parent[i].status);
1002                 putchar(inter_name_termination);
1003         }
1004
1005         write_name_quoted(p->path, stdout, line_termination);
1006 }
1007
1008 void show_combined_diff(struct combine_diff_path *p,
1009                        int num_parent,
1010                        int dense,
1011                        struct rev_info *rev)
1012 {
1013         struct diff_options *opt = &rev->diffopt;
1014         if (!p->len)
1015                 return;
1016         if (opt->output_format & (DIFF_FORMAT_RAW |
1017                                   DIFF_FORMAT_NAME |
1018                                   DIFF_FORMAT_NAME_STATUS))
1019                 show_raw_diff(p, num_parent, rev);
1020         else if (opt->output_format & DIFF_FORMAT_PATCH)
1021                 show_patch_diff(p, num_parent, dense, rev);
1022 }
1023
1024 void diff_tree_combined(const unsigned char *sha1,
1025                         const unsigned char parent[][20],
1026                         int num_parent,
1027                         int dense,
1028                         struct rev_info *rev)
1029 {
1030         struct diff_options *opt = &rev->diffopt;
1031         struct diff_options diffopts;
1032         struct combine_diff_path *p, *paths = NULL;
1033         int i, num_paths, needsep, show_log_first;
1034
1035         diffopts = *opt;
1036         diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
1037         DIFF_OPT_SET(&diffopts, RECURSIVE);
1038         DIFF_OPT_CLR(&diffopts, ALLOW_EXTERNAL);
1039
1040         show_log_first = !!rev->loginfo && !rev->no_commit_id;
1041         needsep = 0;
1042         /* find set of paths that everybody touches */
1043         for (i = 0; i < num_parent; i++) {
1044                 /* show stat against the first parent even
1045                  * when doing combined diff.
1046                  */
1047                 int stat_opt = (opt->output_format &
1048                                 (DIFF_FORMAT_NUMSTAT|DIFF_FORMAT_DIFFSTAT));
1049                 if (i == 0 && stat_opt)
1050                         diffopts.output_format = stat_opt;
1051                 else
1052                         diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
1053                 diff_tree_sha1(parent[i], sha1, "", &diffopts);
1054                 diffcore_std(&diffopts);
1055                 paths = intersect_paths(paths, i, num_parent);
1056
1057                 if (show_log_first && i == 0) {
1058                         show_log(rev);
1059                         if (rev->verbose_header && opt->output_format)
1060                                 putchar(opt->line_termination);
1061                 }
1062                 diff_flush(&diffopts);
1063         }
1064
1065         /* find out surviving paths */
1066         for (num_paths = 0, p = paths; p; p = p->next) {
1067                 if (p->len)
1068                         num_paths++;
1069         }
1070         if (num_paths) {
1071                 if (opt->output_format & (DIFF_FORMAT_RAW |
1072                                           DIFF_FORMAT_NAME |
1073                                           DIFF_FORMAT_NAME_STATUS)) {
1074                         for (p = paths; p; p = p->next) {
1075                                 if (p->len)
1076                                         show_raw_diff(p, num_parent, rev);
1077                         }
1078                         needsep = 1;
1079                 }
1080                 else if (opt->output_format &
1081                          (DIFF_FORMAT_NUMSTAT|DIFF_FORMAT_DIFFSTAT))
1082                         needsep = 1;
1083                 if (opt->output_format & DIFF_FORMAT_PATCH) {
1084                         if (needsep)
1085                                 putchar(opt->line_termination);
1086                         for (p = paths; p; p = p->next) {
1087                                 if (p->len)
1088                                         show_patch_diff(p, num_parent, dense,
1089                                                         rev);
1090                         }
1091                 }
1092         }
1093
1094         /* Clean things up */
1095         while (paths) {
1096                 struct combine_diff_path *tmp = paths;
1097                 paths = paths->next;
1098                 free(tmp);
1099         }
1100 }
1101
1102 void diff_tree_combined_merge(const unsigned char *sha1,
1103                              int dense, struct rev_info *rev)
1104 {
1105         int num_parent;
1106         const unsigned char (*parent)[20];
1107         struct commit *commit = lookup_commit(sha1);
1108         struct commit_list *parents;
1109
1110         /* count parents */
1111         for (parents = commit->parents, num_parent = 0;
1112              parents;
1113              parents = parents->next, num_parent++)
1114                 ; /* nothing */
1115
1116         parent = xmalloc(num_parent * sizeof(*parent));
1117         for (parents = commit->parents, num_parent = 0;
1118              parents;
1119              parents = parents->next, num_parent++)
1120                 hashcpy((unsigned char *)(parent + num_parent),
1121                         parents->item->object.sha1);
1122         diff_tree_combined(sha1, parent, num_parent, dense, rev);
1123 }