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,
  97                        unsigned long *size, struct userdiff_driver *textconv,
  98                        const char *path)
  99 {
 100         char *blob;
 101         enum object_type type;
 102
 103         if (S_ISGITLINK(mode)) {
 104                 blob = xmalloc(100);
 105                 *size = snprintf(blob, 100,
 106                                  "Subproject commit %s\n", sha1_to_hex(sha1));
 107         } else if (is_null_sha1(sha1)) {
 108                 /* deleted blob */
 109                 *size = 0;
 110                 return xcalloc(1, 1);
 111         } else if (textconv) {
 112                 struct diff_filespec *df = alloc_filespec(path);
 113                 fill_filespec(df, sha1, mode);
 114                 *size = fill_textconv(textconv, df, &blob);
 115                 free_filespec(df);
 116         } else {
 117                 blob = read_sha1_file(sha1, &type, size);
 118                 if (type != OBJ_BLOB)
 119                         die("object '%s' is not a blob!", sha1_to_hex(sha1));
 120         }
 121         return blob;
 122 }
 123
 124 static void append_lost(struct sline *sline, int n, const char *line, int len)
 125 {
 126         struct lline *lline;
 127         unsigned long this_mask = (1UL<<n);
 128         if (line[len-1] == '\n')
 129                 len--;
 130
 131         /* Check to see if we can squash things */
 132         if (sline->lost_head) {
 133                 lline = sline->next_lost;
 134                 while (lline) {
 135                         if (lline->len == len &&
 136                             !memcmp(lline->line, line, len)) {
 137                                 lline->parent_map |= this_mask;
 138                                 sline->next_lost = lline->next;
 139                                 return;
 140                         }
 141                         lline = lline->next;
 142                 }
 143         }
 144
 145         lline = xmalloc(sizeof(*lline) + len + 1);
 146         lline->len = len;
 147         lline->next = NULL;
 148         lline->parent_map = this_mask;
 149         memcpy(lline->line, line, len);
 150         lline->line[len] = 0;
 151         *sline->lost_tail = lline;
 152         sline->lost_tail = &lline->next;
 153         sline->next_lost = NULL;
 154 }
 155
 156 struct combine_diff_state {
 157         unsigned int lno;
 158         int ob, on, nb, nn;
 159         unsigned long nmask;
 160         int num_parent;
 161         int n;
 162         struct sline *sline;
 163         struct sline *lost_bucket;
 164 };
 165
 166 static void consume_line(void *state_, char *line, unsigned long len)
 167 {
 168         struct combine_diff_state *state = state_;
 169         if (5 < len && !memcmp("@@ -", line, 4)) {
 170                 if (parse_hunk_header(line, len,
 171                                       &state->ob, &state->on,
 172                                       &state->nb, &state->nn))
 173                         return;
 174                 state->lno = state->nb;
 175                 if (state->nn == 0) {
 176                         /* @@ -X,Y +N,0 @@ removed Y lines
 177                          * that would have come *after* line N
 178                          * in the result.  Our lost buckets hang
 179                          * to the line after the removed lines,
 180                          *
 181                          * Note that this is correct even when N == 0,
 182                          * in which case the hunk removes the first
 183                          * line in the file.
 184                          */
 185                         state->lost_bucket = &state->sline[state->nb];
 186                         if (!state->nb)
 187                                 state->nb = 1;
 188                 } else {
 189                         state->lost_bucket = &state->sline[state->nb-1];
 190                 }
 191                 if (!state->sline[state->nb-1].p_lno)
 192                         state->sline[state->nb-1].p_lno =
 193                                 xcalloc(state->num_parent,
 194                                         sizeof(unsigned long));
 195                 state->sline[state->nb-1].p_lno[state->n] = state->ob;
 196                 state->lost_bucket->next_lost = state->lost_bucket->lost_head;
 197                 return;
 198         }
 199         if (!state->lost_bucket)
 200                 return; /* not in any hunk yet */
 201         switch (line[0]) {
 202         case '-':
 203                 append_lost(state->lost_bucket, state->n, line+1, len-1);
 204                 break;
 205         case '+':
 206                 state->sline[state->lno-1].flag |= state->nmask;
 207                 state->lno++;
 208                 break;
 209         }
 210 }
 211
 212 static void combine_diff(const unsigned char *parent, unsigned int mode,
 213                          mmfile_t *result_file,
 214                          struct sline *sline, unsigned int cnt, int n,
 215                          int num_parent, int result_deleted,
 216                          struct userdiff_driver *textconv,
 217                          const char *path)
 218 {
 219         unsigned int p_lno, lno;
 220         unsigned long nmask = (1UL << n);
 221         xpparam_t xpp;
 222         xdemitconf_t xecfg;
 223         mmfile_t parent_file;
 224         struct combine_diff_state state;
 225         unsigned long sz;
 226
 227         if (result_deleted)
 228                 return; /* result deleted */
 229
 230         parent_file.ptr = grab_blob(parent, mode, &sz, textconv, path);
 231         parent_file.size = sz;
 232         memset(&xpp, 0, sizeof(xpp));
 233         xpp.flags = 0;
 234         memset(&xecfg, 0, sizeof(xecfg));
 235         memset(&state, 0, sizeof(state));
 236         state.nmask = nmask;
 237         state.sline = sline;
 238         state.lno = 1;
 239         state.num_parent = num_parent;
 240         state.n = n;
 241
 242         xdi_diff_outf(&parent_file, result_file, consume_line, &state,
 243                       &xpp, &xecfg);
 244         free(parent_file.ptr);
 245
 246         /* Assign line numbers for this parent.
 247          *
 248          * sline[lno].p_lno[n] records the first line number
 249          * (counting from 1) for parent N if the final hunk display
 250          * started by showing sline[lno] (possibly showing the lost
 251          * lines attached to it first).
 252          */
 253         for (lno = 0,  p_lno = 1; lno <= cnt; lno++) {
 254                 struct lline *ll;
 255                 sline[lno].p_lno[n] = p_lno;
 256
 257                 /* How many lines would this sline advance the p_lno? */
 258                 ll = sline[lno].lost_head;
 259                 while (ll) {
 260                         if (ll->parent_map & nmask)
 261                                 p_lno++; /* '-' means parent had it */
 262                         ll = ll->next;
 263                 }
 264                 if (lno < cnt && !(sline[lno].flag & nmask))
 265                         p_lno++; /* no '+' means parent had it */
 266         }
 267         sline[lno].p_lno[n] = p_lno; /* trailer */
 268 }
 269
 270 static unsigned long context = 3;
 271 static char combine_marker = '@';
 272
 273 static int interesting(struct sline *sline, unsigned long all_mask)
 274 {
 275         /* If some parents lost lines here, or if we have added to
 276          * some parent, it is interesting.
 277          */
 278         return ((sline->flag & all_mask) || sline->lost_head);
 279 }
 280
 281 static unsigned long adjust_hunk_tail(struct sline *sline,
 282                                       unsigned long all_mask,
 283                                       unsigned long hunk_begin,
 284                                       unsigned long i)
 285 {
 286         /* i points at the first uninteresting line.  If the last line
 287          * of the hunk was interesting only because it has some
 288          * deletion, then it is not all that interesting for the
 289          * purpose of giving trailing context lines.  This is because
 290          * we output '-' line and then unmodified sline[i-1] itself in
 291          * that case which gives us one extra context line.
 292          */
 293         if ((hunk_begin + 1 <= i) && !(sline[i-1].flag & all_mask))
 294                 i--;
 295         return i;
 296 }
 297
 298 static unsigned long find_next(struct sline *sline,
 299                                unsigned long mark,
 300                                unsigned long i,
 301                                unsigned long cnt,
 302                                int look_for_uninteresting)
 303 {
 304         /* We have examined up to i-1 and are about to look at i.
 305          * Find next interesting or uninteresting line.  Here,
 306          * "interesting" does not mean interesting(), but marked by
 307          * the give_context() function below (i.e. it includes context
 308          * lines that are not interesting to interesting() function
 309          * that are surrounded by interesting() ones.
 310          */
 311         while (i <= cnt)
 312                 if (look_for_uninteresting
 313                     ? !(sline[i].flag & mark)
 314                     : (sline[i].flag & mark))
 315                         return i;
 316                 else
 317                         i++;
 318         return i;
 319 }
 320
 321 static int give_context(struct sline *sline, unsigned long cnt, int num_parent)
 322 {
 323         unsigned long all_mask = (1UL<<num_parent) - 1;
 324         unsigned long mark = (1UL<<num_parent);
 325         unsigned long no_pre_delete = (2UL<<num_parent);
 326         unsigned long i;
 327
 328         /* Two groups of interesting lines may have a short gap of
 329          * uninteresting lines.  Connect such groups to give them a
 330          * bit of context.
 331          *
 332          * We first start from what the interesting() function says,
 333          * and mark them with "mark", and paint context lines with the
 334          * mark.  So interesting() would still say false for such context
 335          * lines but they are treated as "interesting" in the end.
 336          */
 337         i = find_next(sline, mark, 0, cnt, 0);
 338         if (cnt < i)
 339                 return 0;
 340
 341         while (i <= cnt) {
 342                 unsigned long j = (context < i) ? (i - context) : 0;
 343                 unsigned long k;
 344
 345                 /* Paint a few lines before the first interesting line. */
 346                 while (j < i)
 347                         sline[j++].flag |= mark | no_pre_delete;
 348
 349         again:
 350                 /* we know up to i is to be included.  where does the
 351                  * next uninteresting one start?
 352                  */
 353                 j = find_next(sline, mark, i, cnt, 1);
 354                 if (cnt < j)
 355                         break; /* the rest are all interesting */
 356
 357                 /* lookahead context lines */
 358                 k = find_next(sline, mark, j, cnt, 0);
 359                 j = adjust_hunk_tail(sline, all_mask, i, j);
 360
 361                 if (k < j + context) {
 362                         /* k is interesting and [j,k) are not, but
 363                          * paint them interesting because the gap is small.
 364                          */
 365                         while (j < k)
 366                                 sline[j++].flag |= mark;
 367                         i = k;
 368                         goto again;
 369                 }
 370
 371                 /* j is the first uninteresting line and there is
 372                  * no overlap beyond it within context lines.  Paint
 373                  * the trailing edge a bit.
 374                  */
 375                 i = k;
 376                 k = (j + context < cnt+1) ? j + context : cnt+1;
 377                 while (j < k)
 378                         sline[j++].flag |= mark;
 379         }
 380         return 1;
 381 }
 382
 383 static int make_hunks(struct sline *sline, unsigned long cnt,
 384                        int num_parent, int dense)
 385 {
 386         unsigned long all_mask = (1UL<<num_parent) - 1;
 387         unsigned long mark = (1UL<<num_parent);
 388         unsigned long i;
 389         int has_interesting = 0;
 390
 391         for (i = 0; i <= cnt; i++) {
 392                 if (interesting(&sline[i], all_mask))
 393                         sline[i].flag |= mark;
 394                 else
 395                         sline[i].flag &= ~mark;
 396         }
 397         if (!dense)
 398                 return give_context(sline, cnt, num_parent);
 399
 400         /* Look at each hunk, and if we have changes from only one
 401          * parent, or the changes are the same from all but one
 402          * parent, mark that uninteresting.
 403          */
 404         i = 0;
 405         while (i <= cnt) {
 406                 unsigned long j, hunk_begin, hunk_end;
 407                 unsigned long same_diff;
 408                 while (i <= cnt && !(sline[i].flag & mark))
 409                         i++;
 410                 if (cnt < i)
 411                         break; /* No more interesting hunks */
 412                 hunk_begin = i;
 413                 for (j = i + 1; j <= cnt; j++) {
 414                         if (!(sline[j].flag & mark)) {
 415                                 /* Look beyond the end to see if there
 416                                  * is an interesting line after this
 417                                  * hunk within context span.
 418                                  */
 419                                 unsigned long la; /* lookahead */
 420                                 int contin = 0;
 421                                 la = adjust_hunk_tail(sline, all_mask,
 422                                                      hunk_begin, j);
 423                                 la = (la + context < cnt + 1) ?
 424                                         (la + context) : cnt + 1;
 425                                 while (j <= --la) {
 426                                         if (sline[la].flag & mark) {
 427                                                 contin = 1;
 428                                                 break;
 429                                         }
 430                                 }
 431                                 if (!contin)
 432                                         break;
 433                                 j = la;
 434                         }
 435                 }
 436                 hunk_end = j;
 437
 438                 /* [i..hunk_end) are interesting.  Now is it really
 439                  * interesting?  We check if there are only two versions
 440                  * and the result matches one of them.  That is, we look
 441                  * at:
 442                  *   (+) line, which records lines added to which parents;
 443                  *       this line appears in the result.
 444                  *   (-) line, which records from what parents the line
 445                  *       was removed; this line does not appear in the result.
 446                  * then check the set of parents the result has difference
 447                  * from, from all lines.  If there are lines that has
 448                  * different set of parents that the result has differences
 449                  * from, that means we have more than two versions.
 450                  *
 451                  * Even when we have only two versions, if the result does
 452                  * not match any of the parents, the it should be considered
 453                  * interesting.  In such a case, we would have all '+' line.
 454                  * After passing the above "two versions" test, that would
 455                  * appear as "the same set of parents" to be "all parents".
 456                  */
 457                 same_diff = 0;
 458                 has_interesting = 0;
 459                 for (j = i; j < hunk_end && !has_interesting; j++) {
 460                         unsigned long this_diff = sline[j].flag & all_mask;
 461                         struct lline *ll = sline[j].lost_head;
 462                         if (this_diff) {
 463                                 /* This has some changes.  Is it the
 464                                  * same as others?
 465                                  */
 466                                 if (!same_diff)
 467                                         same_diff = this_diff;
 468                                 else if (same_diff != this_diff) {
 469                                         has_interesting = 1;
 470                                         break;
 471                                 }
 472                         }
 473                         while (ll && !has_interesting) {
 474                                 /* Lost this line from these parents;
 475                                  * who are they?  Are they the same?
 476                                  */
 477                                 this_diff = ll->parent_map;
 478                                 if (!same_diff)
 479                                         same_diff = this_diff;
 480                                 else if (same_diff != this_diff) {
 481                                         has_interesting = 1;
 482                                 }
 483                                 ll = ll->next;
 484                         }
 485                 }
 486
 487                 if (!has_interesting && same_diff != all_mask) {
 488                         /* This hunk is not that interesting after all */
 489                         for (j = hunk_begin; j < hunk_end; j++)
 490                                 sline[j].flag &= ~mark;
 491                 }
 492                 i = hunk_end;
 493         }
 494
 495         has_interesting = give_context(sline, cnt, num_parent);
 496         return has_interesting;
 497 }
 498
 499 static void show_parent_lno(struct sline *sline, unsigned long l0, unsigned long l1, int n, unsigned long null_context)
 500 {
 501         l0 = sline[l0].p_lno[n];
 502         l1 = sline[l1].p_lno[n];
 503         printf(" -%lu,%lu", l0, l1-l0-null_context);
 504 }
 505
 506 static int hunk_comment_line(const char *bol)
 507 {
 508         int ch;
 509
 510         if (!bol)
 511                 return 0;
 512         ch = *bol & 0xff;
 513         return (isalpha(ch) || ch == '_' || ch == '$');
 514 }
 515
 516 static void show_line_to_eol(const char *line, int len, const char *reset)
 517 {
 518         int saw_cr_at_eol = 0;
 519         if (len < 0)
 520                 len = strlen(line);
 521         saw_cr_at_eol = (len && line[len-1] == '\r');
 522
 523         printf("%.*s%s%s\n", len - saw_cr_at_eol, line,
 524                reset,
 525                saw_cr_at_eol ? "\r" : "");
 526 }
 527
 528 static void dump_sline(struct sline *sline, unsigned long cnt, int num_parent,
 529                        int use_color, int result_deleted)
 530 {
 531         unsigned long mark = (1UL<<num_parent);
 532         unsigned long no_pre_delete = (2UL<<num_parent);
 533         int i;
 534         unsigned long lno = 0;
 535         const char *c_frag = diff_get_color(use_color, DIFF_FRAGINFO);
 536         const char *c_func = diff_get_color(use_color, DIFF_FUNCINFO);
 537         const char *c_new = diff_get_color(use_color, DIFF_FILE_NEW);
 538         const char *c_old = diff_get_color(use_color, DIFF_FILE_OLD);
 539         const char *c_plain = diff_get_color(use_color, DIFF_PLAIN);
 540         const char *c_reset = diff_get_color(use_color, DIFF_RESET);
 541
 542         if (result_deleted)
 543                 return; /* result deleted */
 544
 545         while (1) {
 546                 unsigned long hunk_end;
 547                 unsigned long rlines;
 548                 const char *hunk_comment = NULL;
 549                 unsigned long null_context = 0;
 550
 551                 while (lno <= cnt && !(sline[lno].flag & mark)) {
 552                         if (hunk_comment_line(sline[lno].bol))
 553                                 hunk_comment = sline[lno].bol;
 554                         lno++;
 555                 }
 556                 if (cnt < lno)
 557                         break;
 558                 else {
 559                         for (hunk_end = lno + 1; hunk_end <= cnt; hunk_end++)
 560                                 if (!(sline[hunk_end].flag & mark))
 561                                         break;
 562                 }
 563                 rlines = hunk_end - lno;
 564                 if (cnt < hunk_end)
 565                         rlines--; /* pointing at the last delete hunk */
 566
 567                 if (!context) {
 568                         /*
 569                          * Even when running with --unified=0, all
 570                          * lines in the hunk needs to be processed in
 571                          * the loop below in order to show the
 572                          * deletion recorded in lost_head.  However,
 573                          * we do not want to show the resulting line
 574                          * with all blank context markers in such a
 575                          * case.  Compensate.
 576                          */
 577                         unsigned long j;
 578                         for (j = lno; j < hunk_end; j++)
 579                                 if (!(sline[j].flag & (mark-1)))
 580                                         null_context++;
 581                         rlines -= null_context;
 582                 }
 583
 584                 fputs(c_frag, stdout);
 585                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 586                 for (i = 0; i < num_parent; i++)
 587                         show_parent_lno(sline, lno, hunk_end, i, null_context);
 588                 printf(" +%lu,%lu ", lno+1, rlines);
 589                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 590
 591                 if (hunk_comment) {
 592                         int comment_end = 0;
 593                         for (i = 0; i < 40; i++) {
 594                                 int ch = hunk_comment[i] & 0xff;
 595                                 if (!ch || ch == '\n')
 596                                         break;
 597                                 if (!isspace(ch))
 598                                     comment_end = i;
 599                         }
 600                         if (comment_end)
 601                                 printf("%s%s %s%s", c_reset,
 602                                                     c_plain, c_reset,
 603                                                     c_func);
 604                         for (i = 0; i < comment_end; i++)
 605                                 putchar(hunk_comment[i]);
 606                 }
 607
 608                 printf("%s\n", c_reset);
 609                 while (lno < hunk_end) {
 610                         struct lline *ll;
 611                         int j;
 612                         unsigned long p_mask;
 613                         struct sline *sl = &sline[lno++];
 614                         ll = (sl->flag & no_pre_delete) ? NULL : sl->lost_head;
 615                         while (ll) {
 616                                 fputs(c_old, stdout);
 617                                 for (j = 0; j < num_parent; j++) {
 618                                         if (ll->parent_map & (1UL<<j))
 619                                                 putchar('-');
 620                                         else
 621                                                 putchar(' ');
 622                                 }
 623                                 show_line_to_eol(ll->line, -1, c_reset);
 624                                 ll = ll->next;
 625                         }
 626                         if (cnt < lno)
 627                                 break;
 628                         p_mask = 1;
 629                         if (!(sl->flag & (mark-1))) {
 630                                 /*
 631                                  * This sline was here to hang the
 632                                  * lost lines in front of it.
 633                                  */
 634                                 if (!context)
 635                                         continue;
 636                                 fputs(c_plain, stdout);
 637                         }
 638                         else
 639                                 fputs(c_new, stdout);
 640                         for (j = 0; j < num_parent; j++) {
 641                                 if (p_mask & sl->flag)
 642                                         putchar('+');
 643                                 else
 644                                         putchar(' ');
 645                                 p_mask <<= 1;
 646                         }
 647                         show_line_to_eol(sl->bol, sl->len, c_reset);
 648                 }
 649         }
 650 }
 651
 652 static void reuse_combine_diff(struct sline *sline, unsigned long cnt,
 653                                int i, int j)
 654 {
 655         /* We have already examined parent j and we know parent i
 656          * and parent j are the same, so reuse the combined result
 657          * of parent j for parent i.
 658          */
 659         unsigned long lno, imask, jmask;
 660         imask = (1UL<<i);
 661         jmask = (1UL<<j);
 662
 663         for (lno = 0; lno <= cnt; lno++) {
 664                 struct lline *ll = sline->lost_head;
 665                 sline->p_lno[i] = sline->p_lno[j];
 666                 while (ll) {
 667                         if (ll->parent_map & jmask)
 668                                 ll->parent_map |= imask;
 669                         ll = ll->next;
 670                 }
 671                 if (sline->flag & jmask)
 672                         sline->flag |= imask;
 673                 sline++;
 674         }
 675         /* the overall size of the file (sline[cnt]) */
 676         sline->p_lno[i] = sline->p_lno[j];
 677 }
 678
 679 static void dump_quoted_path(const char *head,
 680                              const char *prefix,
 681                              const char *path,
 682                              const char *c_meta, const char *c_reset)
 683 {
 684         static struct strbuf buf = STRBUF_INIT;
 685
 686         strbuf_reset(&buf);
 687         strbuf_addstr(&buf, c_meta);
 688         strbuf_addstr(&buf, head);
 689         quote_two_c_style(&buf, prefix, path, 0);
 690         strbuf_addstr(&buf, c_reset);
 691         puts(buf.buf);
 692 }
 693
 694 static void show_combined_header(struct combine_diff_path *elem,
 695                                  int num_parent,
 696                                  int dense,
 697                                  struct rev_info *rev,
 698                                  int mode_differs,
 699                                  int show_file_header)
 700 {
 701         struct diff_options *opt = &rev->diffopt;
 702         int abbrev = DIFF_OPT_TST(opt, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
 703         const char *a_prefix = opt->a_prefix ? opt->a_prefix : "a/";
 704         const char *b_prefix = opt->b_prefix ? opt->b_prefix : "b/";
 705         const char *c_meta = diff_get_color_opt(opt, DIFF_METAINFO);
 706         const char *c_reset = diff_get_color_opt(opt, DIFF_RESET);
 707         const char *abb;
 708         int added = 0;
 709         int deleted = 0;
 710         int i;
 711
 712         if (rev->loginfo && !rev->no_commit_id)
 713                 show_log(rev);
 714
 715         dump_quoted_path(dense ? "diff --cc " : "diff --combined ",
 716                          "", elem->path, c_meta, c_reset);
 717         printf("%sindex ", c_meta);
 718         for (i = 0; i < num_parent; i++) {
 719                 abb = find_unique_abbrev(elem->parent[i].sha1,
 720                                          abbrev);
 721                 printf("%s%s", i ? "," : "", abb);
 722         }
 723         abb = find_unique_abbrev(elem->sha1, abbrev);
 724         printf("..%s%s\n", abb, c_reset);
 725
 726         if (mode_differs) {
 727                 deleted = !elem->mode;
 728
 729                 /* We say it was added if nobody had it */
 730                 added = !deleted;
 731                 for (i = 0; added && i < num_parent; i++)
 732                         if (elem->parent[i].status !=
 733                             DIFF_STATUS_ADDED)
 734                                 added = 0;
 735                 if (added)
 736                         printf("%snew file mode %06o",
 737                                c_meta, elem->mode);
 738                 else {
 739                         if (deleted)
 740                                 printf("%sdeleted file ", c_meta);
 741                         printf("mode ");
 742                         for (i = 0; i < num_parent; i++) {
 743                                 printf("%s%06o", i ? "," : "",
 744                                        elem->parent[i].mode);
 745                         }
 746                         if (elem->mode)
 747                                 printf("..%06o", elem->mode);
 748                 }
 749                 printf("%s\n", c_reset);
 750         }
 751
 752         if (!show_file_header)
 753                 return;
 754
 755         if (added)
 756                 dump_quoted_path("--- ", "", "/dev/null",
 757                                  c_meta, c_reset);
 758         else
 759                 dump_quoted_path("--- ", a_prefix, elem->path,
 760                                  c_meta, c_reset);
 761         if (deleted)
 762                 dump_quoted_path("+++ ", "", "/dev/null",
 763                                  c_meta, c_reset);
 764         else
 765                 dump_quoted_path("+++ ", b_prefix, elem->path,
 766                                  c_meta, c_reset);
 767 }
 768
 769 static void show_patch_diff(struct combine_diff_path *elem, int num_parent,
 770                             int dense, int working_tree_file,
 771                             struct rev_info *rev)
 772 {
 773         struct diff_options *opt = &rev->diffopt;
 774         unsigned long result_size, cnt, lno;
 775         int result_deleted = 0;
 776         char *result, *cp;
 777         struct sline *sline; /* survived lines */
 778         int mode_differs = 0;
 779         int i, show_hunks;
 780         mmfile_t result_file;
 781         struct userdiff_driver *userdiff;
 782         struct userdiff_driver *textconv = NULL;
 783         int is_binary;
 784
 785         context = opt->context;
 786         userdiff = userdiff_find_by_path(elem->path);
 787         if (!userdiff)
 788                 userdiff = userdiff_find_by_name("default");
 789         if (DIFF_OPT_TST(opt, ALLOW_TEXTCONV))
 790                 textconv = userdiff_get_textconv(userdiff);
 791
 792         /* Read the result of merge first */
 793         if (!working_tree_file)
 794                 result = grab_blob(elem->sha1, elem->mode, &result_size,
 795                                    textconv, elem->path);
 796         else {
 797                 /* Used by diff-tree to read from the working tree */
 798                 struct stat st;
 799                 int fd = -1;
 800
 801                 if (lstat(elem->path, &st) < 0)
 802                         goto deleted_file;
 803
 804                 if (S_ISLNK(st.st_mode)) {
 805                         struct strbuf buf = STRBUF_INIT;
 806
 807                         if (strbuf_readlink(&buf, elem->path, st.st_size) < 0) {
 808                                 error("readlink(%s): %s", elem->path,
 809                                       strerror(errno));
 810                                 return;
 811                         }
 812                         result_size = buf.len;
 813                         result = strbuf_detach(&buf, NULL);
 814                         elem->mode = canon_mode(st.st_mode);
 815                 } else if (S_ISDIR(st.st_mode)) {
 816                         unsigned char sha1[20];
 817                         if (resolve_gitlink_ref(elem->path, "HEAD", sha1) < 0)
 818                                 result = grab_blob(elem->sha1, elem->mode,
 819                                                    &result_size, NULL, NULL);
 820                         else
 821                                 result = grab_blob(sha1, elem->mode,
 822                                                    &result_size, NULL, NULL);
 823                 } else if (textconv) {
 824                         struct diff_filespec *df = alloc_filespec(elem->path);
 825                         fill_filespec(df, null_sha1, st.st_mode);
 826                         result_size = fill_textconv(textconv, df, &result);
 827                         free_filespec(df);
 828                 } else if (0 <= (fd = open(elem->path, O_RDONLY))) {
 829                         size_t len = xsize_t(st.st_size);
 830                         ssize_t done;
 831                         int is_file, i;
 832
 833                         elem->mode = canon_mode(st.st_mode);
 834                         /* if symlinks don't work, assume symlink if all parents
 835                          * are symlinks
 836                          */
 837                         is_file = has_symlinks;
 838                         for (i = 0; !is_file && i < num_parent; i++)
 839                                 is_file = !S_ISLNK(elem->parent[i].mode);
 840                         if (!is_file)
 841                                 elem->mode = canon_mode(S_IFLNK);
 842
 843                         result_size = len;
 844                         result = xmalloc(len + 1);
 845
 846                         done = read_in_full(fd, result, len);
 847                         if (done < 0)
 848                                 die_errno("read error '%s'", elem->path);
 849                         else if (done < len)
 850                                 die("early EOF '%s'", elem->path);
 851
 852                         result[len] = 0;
 853
 854                         /* If not a fake symlink, apply filters, e.g. autocrlf */
 855                         if (is_file) {
 856                                 struct strbuf buf = STRBUF_INIT;
 857
 858                                 if (convert_to_git(elem->path, result, len, &buf, safe_crlf)) {
 859                                         free(result);
 860                                         result = strbuf_detach(&buf, &len);
 861                                         result_size = len;
 862                                 }
 863                         }
 864                 }
 865                 else {
 866                 deleted_file:
 867                         result_deleted = 1;
 868                         result_size = 0;
 869                         elem->mode = 0;
 870                         result = xcalloc(1, 1);
 871                 }
 872
 873                 if (0 <= fd)
 874                         close(fd);
 875         }
 876
 877         for (i = 0; i < num_parent; i++) {
 878                 if (elem->parent[i].mode != elem->mode) {
 879                         mode_differs = 1;
 880                         break;
 881                 }
 882         }
 883
 884         if (textconv)
 885                 is_binary = 0;
 886         else if (userdiff->binary != -1)
 887                 is_binary = userdiff->binary;
 888         else {
 889                 is_binary = buffer_is_binary(result, result_size);
 890                 for (i = 0; !is_binary && i < num_parent; i++) {
 891                         char *buf;
 892                         unsigned long size;
 893                         buf = grab_blob(elem->parent[i].sha1,
 894                                         elem->parent[i].mode,
 895                                         &size, NULL, NULL);
 896                         if (buffer_is_binary(buf, size))
 897                                 is_binary = 1;
 898                         free(buf);
 899                 }
 900         }
 901         if (is_binary) {
 902                 show_combined_header(elem, num_parent, dense, rev,
 903                                      mode_differs, 0);
 904                 printf("Binary files differ\n");
 905                 free(result);
 906                 return;
 907         }
 908
 909         for (cnt = 0, cp = result; cp < result + result_size; cp++) {
 910                 if (*cp == '\n')
 911                         cnt++;
 912         }
 913         if (result_size && result[result_size-1] != '\n')
 914                 cnt++; /* incomplete line */
 915
 916         sline = xcalloc(cnt+2, sizeof(*sline));
 917         sline[0].bol = result;
 918         for (lno = 0; lno <= cnt + 1; lno++) {
 919                 sline[lno].lost_tail = &sline[lno].lost_head;
 920                 sline[lno].flag = 0;
 921         }
 922         for (lno = 0, cp = result; cp < result + result_size; cp++) {
 923                 if (*cp == '\n') {
 924                         sline[lno].len = cp - sline[lno].bol;
 925                         lno++;
 926                         if (lno < cnt)
 927                                 sline[lno].bol = cp + 1;
 928                 }
 929         }
 930         if (result_size && result[result_size-1] != '\n')
 931                 sline[cnt-1].len = result_size - (sline[cnt-1].bol - result);
 932
 933         result_file.ptr = result;
 934         result_file.size = result_size;
 935
 936         /* Even p_lno[cnt+1] is valid -- that is for the end line number
 937          * for deletion hunk at the end.
 938          */
 939         sline[0].p_lno = xcalloc((cnt+2) * num_parent, sizeof(unsigned long));
 940         for (lno = 0; lno <= cnt; lno++)
 941                 sline[lno+1].p_lno = sline[lno].p_lno + num_parent;
 942
 943         for (i = 0; i < num_parent; i++) {
 944                 int j;
 945                 for (j = 0; j < i; j++) {
 946                         if (!hashcmp(elem->parent[i].sha1,
 947                                      elem->parent[j].sha1)) {
 948                                 reuse_combine_diff(sline, cnt, i, j);
 949                                 break;
 950                         }
 951                 }
 952                 if (i <= j)
 953                         combine_diff(elem->parent[i].sha1,
 954                                      elem->parent[i].mode,
 955                                      &result_file, sline,
 956                                      cnt, i, num_parent, result_deleted,
 957                                      textconv, elem->path);
 958         }
 959
 960         show_hunks = make_hunks(sline, cnt, num_parent, dense);
 961
 962         if (show_hunks || mode_differs || working_tree_file) {
 963                 show_combined_header(elem, num_parent, dense, rev,
 964                                      mode_differs, 1);
 965                 dump_sline(sline, cnt, num_parent,
 966                            opt->use_color, result_deleted);
 967         }
 968         free(result);
 969
 970         for (lno = 0; lno < cnt; lno++) {
 971                 if (sline[lno].lost_head) {
 972                         struct lline *ll = sline[lno].lost_head;
 973                         while (ll) {
 974                                 struct lline *tmp = ll;
 975                                 ll = ll->next;
 976                                 free(tmp);
 977                         }
 978                 }
 979         }
 980         free(sline[0].p_lno);
 981         free(sline);
 982 }
 983
 984 #define COLONS "::::::::::::::::::::::::::::::::"
 985
 986 static void show_raw_diff(struct combine_diff_path *p, int num_parent, struct rev_info *rev)
 987 {
 988         struct diff_options *opt = &rev->diffopt;
 989         int i, offset;
 990         const char *prefix;
 991         int line_termination, inter_name_termination;
 992
 993         line_termination = opt->line_termination;
 994         inter_name_termination = '\t';
 995         if (!line_termination)
 996                 inter_name_termination = 0;
 997
 998         if (rev->loginfo && !rev->no_commit_id)
 999                 show_log(rev);
1000
1001         if (opt->output_format & DIFF_FORMAT_RAW) {
1002                 offset = strlen(COLONS) - num_parent;
1003                 if (offset < 0)
1004                         offset = 0;
1005                 prefix = COLONS + offset;
1006
1007                 /* Show the modes */
1008                 for (i = 0; i < num_parent; i++) {
1009                         printf("%s%06o", prefix, p->parent[i].mode);
1010                         prefix = " ";
1011                 }
1012                 printf("%s%06o", prefix, p->mode);
1013
1014                 /* Show sha1's */
1015                 for (i = 0; i < num_parent; i++)
1016                         printf(" %s", diff_unique_abbrev(p->parent[i].sha1,
1017                                                          opt->abbrev));
1018                 printf(" %s ", diff_unique_abbrev(p->sha1, opt->abbrev));
1019         }
1020
1021         if (opt->output_format & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS)) {
1022                 for (i = 0; i < num_parent; i++)
1023                         putchar(p->parent[i].status);
1024                 putchar(inter_name_termination);
1025         }
1026
1027         write_name_quoted(p->path, stdout, line_termination);
1028 }
1029
1030 /*
1031  * The result (p->elem) is from the working tree and their
1032  * parents are typically from multiple stages during a merge
1033  * (i.e. diff-files) or the state in HEAD and in the index
1034  * (i.e. diff-index).
1035  */
1036 void show_combined_diff(struct combine_diff_path *p,
1037                        int num_parent,
1038                        int dense,
1039                        struct rev_info *rev)
1040 {
1041         struct diff_options *opt = &rev->diffopt;
1042         if (!p->len)
1043                 return;
1044         if (opt->output_format & (DIFF_FORMAT_RAW |
1045                                   DIFF_FORMAT_NAME |
1046                                   DIFF_FORMAT_NAME_STATUS))
1047                 show_raw_diff(p, num_parent, rev);
1048         else if (opt->output_format & DIFF_FORMAT_PATCH)
1049                 show_patch_diff(p, num_parent, dense, 1, rev);
1050 }
1051
1052 static void free_combined_pair(struct diff_filepair *pair)
1053 {
1054         free(pair->two);
1055         free(pair);
1056 }
1057
1058 /*
1059  * A combine_diff_path expresses N parents on the LHS against 1 merge
1060  * result. Synthesize a diff_filepair that has N entries on the "one"
1061  * side and 1 entry on the "two" side.
1062  *
1063  * In the future, we might want to add more data to combine_diff_path
1064  * so that we can fill fields we are ignoring (most notably, size) here,
1065  * but currently nobody uses it, so this should suffice for now.
1066  */
1067 static struct diff_filepair *combined_pair(struct combine_diff_path *p,
1068                                            int num_parent)
1069 {
1070         int i;
1071         struct diff_filepair *pair;
1072         struct diff_filespec *pool;
1073
1074         pair = xmalloc(sizeof(*pair));
1075         pool = xcalloc(num_parent + 1, sizeof(struct diff_filespec));
1076         pair->one = pool + 1;
1077         pair->two = pool;
1078
1079         for (i = 0; i < num_parent; i++) {
1080                 pair->one[i].path = p->path;
1081                 pair->one[i].mode = p->parent[i].mode;
1082                 hashcpy(pair->one[i].sha1, p->parent[i].sha1);
1083                 pair->one[i].sha1_valid = !is_null_sha1(p->parent[i].sha1);
1084                 pair->one[i].has_more_entries = 1;
1085         }
1086         pair->one[num_parent - 1].has_more_entries = 0;
1087
1088         pair->two->path = p->path;
1089         pair->two->mode = p->mode;
1090         hashcpy(pair->two->sha1, p->sha1);
1091         pair->two->sha1_valid = !is_null_sha1(p->sha1);
1092         return pair;
1093 }
1094
1095 static void handle_combined_callback(struct diff_options *opt,
1096                                      struct combine_diff_path *paths,
1097                                      int num_parent,
1098                                      int num_paths)
1099 {
1100         struct combine_diff_path *p;
1101         struct diff_queue_struct q;
1102         int i;
1103
1104         q.queue = xcalloc(num_paths, sizeof(struct diff_filepair *));
1105         q.alloc = num_paths;
1106         q.nr = num_paths;
1107         for (i = 0, p = paths; p; p = p->next) {
1108                 if (!p->len)
1109                         continue;
1110                 q.queue[i++] = combined_pair(p, num_parent);
1111         }
1112         opt->format_callback(&q, opt, opt->format_callback_data);
1113         for (i = 0; i < num_paths; i++)
1114                 free_combined_pair(q.queue[i]);
1115         free(q.queue);
1116 }
1117
1118 void diff_tree_combined(const unsigned char *sha1,
1119                         const unsigned char parent[][20],
1120                         int num_parent,
1121                         int dense,
1122                         struct rev_info *rev)
1123 {
1124         struct diff_options *opt = &rev->diffopt;
1125         struct diff_options diffopts;
1126         struct combine_diff_path *p, *paths = NULL;
1127         int i, num_paths, needsep, show_log_first;
1128
1129         diffopts = *opt;
1130         diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
1131         DIFF_OPT_SET(&diffopts, RECURSIVE);
1132         DIFF_OPT_CLR(&diffopts, ALLOW_EXTERNAL);
1133
1134         show_log_first = !!rev->loginfo && !rev->no_commit_id;
1135         needsep = 0;
1136         /* find set of paths that everybody touches */
1137         for (i = 0; i < num_parent; i++) {
1138                 /* show stat against the first parent even
1139                  * when doing combined diff.
1140                  */
1141                 int stat_opt = (opt->output_format &
1142                                 (DIFF_FORMAT_NUMSTAT|DIFF_FORMAT_DIFFSTAT));
1143                 if (i == 0 && stat_opt)
1144                         diffopts.output_format = stat_opt;
1145                 else
1146                         diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
1147                 diff_tree_sha1(parent[i], sha1, "", &diffopts);
1148                 diffcore_std(&diffopts);
1149                 paths = intersect_paths(paths, i, num_parent);
1150
1151                 if (show_log_first && i == 0) {
1152                         show_log(rev);
1153                         if (rev->verbose_header && opt->output_format)
1154                                 putchar(opt->line_termination);
1155                 }
1156                 diff_flush(&diffopts);
1157         }
1158
1159         /* find out surviving paths */
1160         for (num_paths = 0, p = paths; p; p = p->next) {
1161                 if (p->len)
1162                         num_paths++;
1163         }
1164         if (num_paths) {
1165                 if (opt->output_format & (DIFF_FORMAT_RAW |
1166                                           DIFF_FORMAT_NAME |
1167                                           DIFF_FORMAT_NAME_STATUS)) {
1168                         for (p = paths; p; p = p->next) {
1169                                 if (p->len)
1170                                         show_raw_diff(p, num_parent, rev);
1171                         }
1172                         needsep = 1;
1173                 }
1174                 else if (opt->output_format &
1175                          (DIFF_FORMAT_NUMSTAT|DIFF_FORMAT_DIFFSTAT))
1176                         needsep = 1;
1177                 else if (opt->output_format & DIFF_FORMAT_CALLBACK)
1178                         handle_combined_callback(opt, paths, num_parent, num_paths);
1179
1180                 if (opt->output_format & DIFF_FORMAT_PATCH) {
1181                         if (needsep)
1182                                 putchar(opt->line_termination);
1183                         for (p = paths; p; p = p->next) {
1184                                 if (p->len)
1185                                         show_patch_diff(p, num_parent, dense,
1186                                                         0, rev);
1187                         }
1188                 }
1189         }
1190
1191         /* Clean things up */
1192         while (paths) {
1193                 struct combine_diff_path *tmp = paths;
1194                 paths = paths->next;
1195                 free(tmp);
1196         }
1197 }
1198
1199 void diff_tree_combined_merge(const unsigned char *sha1,
1200                              int dense, struct rev_info *rev)
1201 {
1202         int num_parent;
1203         const unsigned char (*parent)[20];
1204         struct commit *commit = lookup_commit(sha1);
1205         struct commit_list *parents;
1206
1207         /* count parents */
1208         for (parents = commit->parents, num_parent = 0;
1209              parents;
1210              parents = parents->next, num_parent++)
1211                 ; /* nothing */
1212
1213         parent = xmalloc(num_parent * sizeof(*parent));
1214         for (parents = commit->parents, num_parent = 0;
1215              parents;
1216              parents = parents->next, num_parent++)
1217                 hashcpy((unsigned char *)(parent + num_parent),
1218                         parents->item->object.sha1);
1219         diff_tree_combined(sha1, parent, num_parent, dense, rev);
1220 }