git.oblomov.eu Git - git/blob - 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 "xdiff/xmacros.h"
   9 #include "log-tree.h"
  10 #include "refs.h"
  11 #include "userdiff.h"
  12 #include "sha1-array.h"
  13
  14 static struct combine_diff_path *intersect_paths(struct combine_diff_path *curr, int n, int num_parent)
  15 {
  16         struct diff_queue_struct *q = &diff_queued_diff;
  17         struct combine_diff_path *p;
  18         int i;
  19
  20         if (!n) {
  21                 struct combine_diff_path *list = NULL, **tail = &list;
  22                 for (i = 0; i < q->nr; i++) {
  23                         int len;
  24                         const char *path;
  25                         if (diff_unmodified_pair(q->queue[i]))
  26                                 continue;
  27                         path = q->queue[i]->two->path;
  28                         len = strlen(path);
  29                         p = xmalloc(combine_diff_path_size(num_parent, len));
  30                         p->path = (char *) &(p->parent[num_parent]);
  31                         memcpy(p->path, path, len);
  32                         p->path[len] = 0;
  33                         p->len = len;
  34                         p->next = NULL;
  35                         memset(p->parent, 0,
  36                                sizeof(p->parent[0]) * num_parent);
  37
  38                         hashcpy(p->sha1, q->queue[i]->two->sha1);
  39                         p->mode = q->queue[i]->two->mode;
  40                         hashcpy(p->parent[n].sha1, q->queue[i]->one->sha1);
  41                         p->parent[n].mode = q->queue[i]->one->mode;
  42                         p->parent[n].status = q->queue[i]->status;
  43                         *tail = p;
  44                         tail = &p->next;
  45                 }
  46                 return list;
  47         }
  48
  49         for (p = curr; p; p = p->next) {
  50                 int found = 0;
  51                 if (!p->len)
  52                         continue;
  53                 for (i = 0; i < q->nr; i++) {
  54                         const char *path;
  55                         int len;
  56
  57                         if (diff_unmodified_pair(q->queue[i]))
  58                                 continue;
  59                         path = q->queue[i]->two->path;
  60                         len = strlen(path);
  61                         if (len == p->len && !memcmp(path, p->path, len)) {
  62                                 found = 1;
  63                                 hashcpy(p->parent[n].sha1, q->queue[i]->one->sha1);
  64                                 p->parent[n].mode = q->queue[i]->one->mode;
  65                                 p->parent[n].status = q->queue[i]->status;
  66                                 break;
  67                         }
  68                 }
  69                 if (!found)
  70                         p->len = 0;
  71         }
  72         return curr;
  73 }
  74
  75 /* Lines lost from parent */
  76 struct lline {
  77         struct lline *next;
  78         int len;
  79         unsigned long parent_map;
  80         char line[FLEX_ARRAY];
  81 };
  82
  83 /* Lines surviving in the merge result */
  84 struct sline {
  85         struct lline *lost_head, **lost_tail;
  86         struct lline *next_lost;
  87         char *bol;
  88         int len;
  89         /* bit 0 up to (N-1) are on if the parent has this line (i.e.
  90          * we did not change it).
  91          * bit N is used for "interesting" lines, including context.
  92          * bit (N+1) is used for "do not show deletion before this".
  93          */
  94         unsigned long flag;
  95         unsigned long *p_lno;
  96 };
  97
  98 static char *grab_blob(const unsigned char *sha1, unsigned int mode,
  99                        unsigned long *size, struct userdiff_driver *textconv,
 100                        const char *path)
 101 {
 102         char *blob;
 103         enum object_type type;
 104
 105         if (S_ISGITLINK(mode)) {
 106                 blob = xmalloc(100);
 107                 *size = snprintf(blob, 100,
 108                                  "Subproject commit %s\n", sha1_to_hex(sha1));
 109         } else if (is_null_sha1(sha1)) {
 110                 /* deleted blob */
 111                 *size = 0;
 112                 return xcalloc(1, 1);
 113         } else if (textconv) {
 114                 struct diff_filespec *df = alloc_filespec(path);
 115                 fill_filespec(df, sha1, 1, mode);
 116                 *size = fill_textconv(textconv, df, &blob);
 117                 free_filespec(df);
 118         } else {
 119                 blob = read_sha1_file(sha1, &type, size);
 120                 if (type != OBJ_BLOB)
 121                         die("object '%s' is not a blob!", sha1_to_hex(sha1));
 122         }
 123         return blob;
 124 }
 125
 126 static int match_string_spaces(const char *line1, int len1,
 127                                const char *line2, int len2,
 128                                long flags)
 129 {
 130         if (flags & XDF_WHITESPACE_FLAGS) {
 131                 for (; len1 > 0 && XDL_ISSPACE(line1[len1 - 1]); len1--);
 132                 for (; len2 > 0 && XDL_ISSPACE(line2[len2 - 1]); len2--);
 133         }
 134
 135         if (!(flags & (XDF_IGNORE_WHITESPACE | XDF_IGNORE_WHITESPACE_CHANGE)))
 136                 return (len1 == len2 && !memcmp(line1, line2, len1));
 137
 138         while (len1 > 0 && len2 > 0) {
 139                 len1--;
 140                 len2--;
 141                 if (XDL_ISSPACE(line1[len1]) || XDL_ISSPACE(line2[len2])) {
 142                         if ((flags & XDF_IGNORE_WHITESPACE_CHANGE) &&
 143                             (!XDL_ISSPACE(line1[len1]) || !XDL_ISSPACE(line2[len2])))
 144                                 return 0;
 145
 146                         for (; len1 > 0 && XDL_ISSPACE(line1[len1]); len1--);
 147                         for (; len2 > 0 && XDL_ISSPACE(line2[len2]); len2--);
 148                 }
 149                 if (line1[len1] != line2[len2])
 150                         return 0;
 151         }
 152
 153         if (flags & XDF_IGNORE_WHITESPACE) {
 154                 /* Consume remaining spaces */
 155                 for (; len1 > 0 && XDL_ISSPACE(line1[len1 - 1]); len1--);
 156                 for (; len2 > 0 && XDL_ISSPACE(line2[len2 - 1]); len2--);
 157         }
 158
 159         /* We matched full line1 and line2 */
 160         if (!len1 && !len2)
 161                 return 1;
 162
 163         return 0;
 164 }
 165
 166 static void append_lost(struct sline *sline, int n, const char *line, int len, long flags)
 167 {
 168         struct lline *lline;
 169         unsigned long this_mask = (1UL<<n);
 170         if (line[len-1] == '\n')
 171                 len--;
 172
 173         /* Check to see if we can squash things */
 174         if (sline->lost_head) {
 175                 lline = sline->next_lost;
 176                 while (lline) {
 177                         if (match_string_spaces(lline->line, lline->len,
 178                                                 line, len, flags)) {
 179                                 lline->parent_map |= this_mask;
 180                                 sline->next_lost = lline->next;
 181                                 return;
 182                         }
 183                         lline = lline->next;
 184                 }
 185         }
 186
 187         lline = xmalloc(sizeof(*lline) + len + 1);
 188         lline->len = len;
 189         lline->next = NULL;
 190         lline->parent_map = this_mask;
 191         memcpy(lline->line, line, len);
 192         lline->line[len] = 0;
 193         *sline->lost_tail = lline;
 194         sline->lost_tail = &lline->next;
 195         sline->next_lost = NULL;
 196 }
 197
 198 struct combine_diff_state {
 199         unsigned int lno;
 200         int ob, on, nb, nn;
 201         unsigned long nmask;
 202         int num_parent;
 203         int n;
 204         struct sline *sline;
 205         struct sline *lost_bucket;
 206         long flags;
 207 };
 208
 209 static void consume_line(void *state_, char *line, unsigned long len)
 210 {
 211         struct combine_diff_state *state = state_;
 212         if (5 < len && !memcmp("@@ -", line, 4)) {
 213                 if (parse_hunk_header(line, len,
 214                                       &state->ob, &state->on,
 215                                       &state->nb, &state->nn))
 216                         return;
 217                 state->lno = state->nb;
 218                 if (state->nn == 0) {
 219                         /* @@ -X,Y +N,0 @@ removed Y lines
 220                          * that would have come *after* line N
 221                          * in the result.  Our lost buckets hang
 222                          * to the line after the removed lines,
 223                          *
 224                          * Note that this is correct even when N == 0,
 225                          * in which case the hunk removes the first
 226                          * line in the file.
 227                          */
 228                         state->lost_bucket = &state->sline[state->nb];
 229                         if (!state->nb)
 230                                 state->nb = 1;
 231                 } else {
 232                         state->lost_bucket = &state->sline[state->nb-1];
 233                 }
 234                 if (!state->sline[state->nb-1].p_lno)
 235                         state->sline[state->nb-1].p_lno =
 236                                 xcalloc(state->num_parent,
 237                                         sizeof(unsigned long));
 238                 state->sline[state->nb-1].p_lno[state->n] = state->ob;
 239                 state->lost_bucket->next_lost = state->lost_bucket->lost_head;
 240                 return;
 241         }
 242         if (!state->lost_bucket)
 243                 return; /* not in any hunk yet */
 244         switch (line[0]) {
 245         case '-':
 246                 append_lost(state->lost_bucket, state->n, line+1, len-1, state->flags);
 247                 break;
 248         case '+':
 249                 state->sline[state->lno-1].flag |= state->nmask;
 250                 state->lno++;
 251                 break;
 252         }
 253 }
 254
 255 static void combine_diff(const unsigned char *parent, unsigned int mode,
 256                          mmfile_t *result_file,
 257                          struct sline *sline, unsigned int cnt, int n,
 258                          int num_parent, int result_deleted,
 259                          struct userdiff_driver *textconv,
 260                          const char *path, long flags)
 261 {
 262         unsigned int p_lno, lno;
 263         unsigned long nmask = (1UL << n);
 264         xpparam_t xpp;
 265         xdemitconf_t xecfg;
 266         mmfile_t parent_file;
 267         struct combine_diff_state state;
 268         unsigned long sz;
 269
 270         if (result_deleted)
 271                 return; /* result deleted */
 272
 273         parent_file.ptr = grab_blob(parent, mode, &sz, textconv, path);
 274         parent_file.size = sz;
 275         memset(&xpp, 0, sizeof(xpp));
 276         xpp.flags = flags;
 277         memset(&xecfg, 0, sizeof(xecfg));
 278         memset(&state, 0, sizeof(state));
 279         state.flags = flags;
 280         state.nmask = nmask;
 281         state.sline = sline;
 282         state.lno = 1;
 283         state.num_parent = num_parent;
 284         state.n = n;
 285
 286         xdi_diff_outf(&parent_file, result_file, consume_line, &state,
 287                       &xpp, &xecfg);
 288         free(parent_file.ptr);
 289
 290         /* Assign line numbers for this parent.
 291          *
 292          * sline[lno].p_lno[n] records the first line number
 293          * (counting from 1) for parent N if the final hunk display
 294          * started by showing sline[lno] (possibly showing the lost
 295          * lines attached to it first).
 296          */
 297         for (lno = 0,  p_lno = 1; lno <= cnt; lno++) {
 298                 struct lline *ll;
 299                 sline[lno].p_lno[n] = p_lno;
 300
 301                 /* How many lines would this sline advance the p_lno? */
 302                 ll = sline[lno].lost_head;
 303                 while (ll) {
 304                         if (ll->parent_map & nmask)
 305                                 p_lno++; /* '-' means parent had it */
 306                         ll = ll->next;
 307                 }
 308                 if (lno < cnt && !(sline[lno].flag & nmask))
 309                         p_lno++; /* no '+' means parent had it */
 310         }
 311         sline[lno].p_lno[n] = p_lno; /* trailer */
 312 }
 313
 314 static unsigned long context = 3;
 315 static char combine_marker = '@';
 316
 317 static int interesting(struct sline *sline, unsigned long all_mask)
 318 {
 319         /* If some parents lost lines here, or if we have added to
 320          * some parent, it is interesting.
 321          */
 322         return ((sline->flag & all_mask) || sline->lost_head);
 323 }
 324
 325 static unsigned long adjust_hunk_tail(struct sline *sline,
 326                                       unsigned long all_mask,
 327                                       unsigned long hunk_begin,
 328                                       unsigned long i)
 329 {
 330         /* i points at the first uninteresting line.  If the last line
 331          * of the hunk was interesting only because it has some
 332          * deletion, then it is not all that interesting for the
 333          * purpose of giving trailing context lines.  This is because
 334          * we output '-' line and then unmodified sline[i-1] itself in
 335          * that case which gives us one extra context line.
 336          */
 337         if ((hunk_begin + 1 <= i) && !(sline[i-1].flag & all_mask))
 338                 i--;
 339         return i;
 340 }
 341
 342 static unsigned long find_next(struct sline *sline,
 343                                unsigned long mark,
 344                                unsigned long i,
 345                                unsigned long cnt,
 346                                int look_for_uninteresting)
 347 {
 348         /* We have examined up to i-1 and are about to look at i.
 349          * Find next interesting or uninteresting line.  Here,
 350          * "interesting" does not mean interesting(), but marked by
 351          * the give_context() function below (i.e. it includes context
 352          * lines that are not interesting to interesting() function
 353          * that are surrounded by interesting() ones.
 354          */
 355         while (i <= cnt)
 356                 if (look_for_uninteresting
 357                     ? !(sline[i].flag & mark)
 358                     : (sline[i].flag & mark))
 359                         return i;
 360                 else
 361                         i++;
 362         return i;
 363 }
 364
 365 static int give_context(struct sline *sline, unsigned long cnt, int num_parent)
 366 {
 367         unsigned long all_mask = (1UL<<num_parent) - 1;
 368         unsigned long mark = (1UL<<num_parent);
 369         unsigned long no_pre_delete = (2UL<<num_parent);
 370         unsigned long i;
 371
 372         /* Two groups of interesting lines may have a short gap of
 373          * uninteresting lines.  Connect such groups to give them a
 374          * bit of context.
 375          *
 376          * We first start from what the interesting() function says,
 377          * and mark them with "mark", and paint context lines with the
 378          * mark.  So interesting() would still say false for such context
 379          * lines but they are treated as "interesting" in the end.
 380          */
 381         i = find_next(sline, mark, 0, cnt, 0);
 382         if (cnt < i)
 383                 return 0;
 384
 385         while (i <= cnt) {
 386                 unsigned long j = (context < i) ? (i - context) : 0;
 387                 unsigned long k;
 388
 389                 /* Paint a few lines before the first interesting line. */
 390                 while (j < i)
 391                         sline[j++].flag |= mark | no_pre_delete;
 392
 393         again:
 394                 /* we know up to i is to be included.  where does the
 395                  * next uninteresting one start?
 396                  */
 397                 j = find_next(sline, mark, i, cnt, 1);
 398                 if (cnt < j)
 399                         break; /* the rest are all interesting */
 400
 401                 /* lookahead context lines */
 402                 k = find_next(sline, mark, j, cnt, 0);
 403                 j = adjust_hunk_tail(sline, all_mask, i, j);
 404
 405                 if (k < j + context) {
 406                         /* k is interesting and [j,k) are not, but
 407                          * paint them interesting because the gap is small.
 408                          */
 409                         while (j < k)
 410                                 sline[j++].flag |= mark;
 411                         i = k;
 412                         goto again;
 413                 }
 414
 415                 /* j is the first uninteresting line and there is
 416                  * no overlap beyond it within context lines.  Paint
 417                  * the trailing edge a bit.
 418                  */
 419                 i = k;
 420                 k = (j + context < cnt+1) ? j + context : cnt+1;
 421                 while (j < k)
 422                         sline[j++].flag |= mark;
 423         }
 424         return 1;
 425 }
 426
 427 static int make_hunks(struct sline *sline, unsigned long cnt,
 428                        int num_parent, int dense)
 429 {
 430         unsigned long all_mask = (1UL<<num_parent) - 1;
 431         unsigned long mark = (1UL<<num_parent);
 432         unsigned long i;
 433         int has_interesting = 0;
 434
 435         for (i = 0; i <= cnt; i++) {
 436                 if (interesting(&sline[i], all_mask))
 437                         sline[i].flag |= mark;
 438                 else
 439                         sline[i].flag &= ~mark;
 440         }
 441         if (!dense)
 442                 return give_context(sline, cnt, num_parent);
 443
 444         /* Look at each hunk, and if we have changes from only one
 445          * parent, or the changes are the same from all but one
 446          * parent, mark that uninteresting.
 447          */
 448         i = 0;
 449         while (i <= cnt) {
 450                 unsigned long j, hunk_begin, hunk_end;
 451                 unsigned long same_diff;
 452                 while (i <= cnt && !(sline[i].flag & mark))
 453                         i++;
 454                 if (cnt < i)
 455                         break; /* No more interesting hunks */
 456                 hunk_begin = i;
 457                 for (j = i + 1; j <= cnt; j++) {
 458                         if (!(sline[j].flag & mark)) {
 459                                 /* Look beyond the end to see if there
 460                                  * is an interesting line after this
 461                                  * hunk within context span.
 462                                  */
 463                                 unsigned long la; /* lookahead */
 464                                 int contin = 0;
 465                                 la = adjust_hunk_tail(sline, all_mask,
 466                                                      hunk_begin, j);
 467                                 la = (la + context < cnt + 1) ?
 468                                         (la + context) : cnt + 1;
 469                                 while (la && j <= --la) {
 470                                         if (sline[la].flag & mark) {
 471                                                 contin = 1;
 472                                                 break;
 473                                         }
 474                                 }
 475                                 if (!contin)
 476                                         break;
 477                                 j = la;
 478                         }
 479                 }
 480                 hunk_end = j;
 481
 482                 /* [i..hunk_end) are interesting.  Now is it really
 483                  * interesting?  We check if there are only two versions
 484                  * and the result matches one of them.  That is, we look
 485                  * at:
 486                  *   (+) line, which records lines added to which parents;
 487                  *       this line appears in the result.
 488                  *   (-) line, which records from what parents the line
 489                  *       was removed; this line does not appear in the result.
 490                  * then check the set of parents the result has difference
 491                  * from, from all lines.  If there are lines that has
 492                  * different set of parents that the result has differences
 493                  * from, that means we have more than two versions.
 494                  *
 495                  * Even when we have only two versions, if the result does
 496                  * not match any of the parents, the it should be considered
 497                  * interesting.  In such a case, we would have all '+' line.
 498                  * After passing the above "two versions" test, that would
 499                  * appear as "the same set of parents" to be "all parents".
 500                  */
 501                 same_diff = 0;
 502                 has_interesting = 0;
 503                 for (j = i; j < hunk_end && !has_interesting; j++) {
 504                         unsigned long this_diff = sline[j].flag & all_mask;
 505                         struct lline *ll = sline[j].lost_head;
 506                         if (this_diff) {
 507                                 /* This has some changes.  Is it the
 508                                  * same as others?
 509                                  */
 510                                 if (!same_diff)
 511                                         same_diff = this_diff;
 512                                 else if (same_diff != this_diff) {
 513                                         has_interesting = 1;
 514                                         break;
 515                                 }
 516                         }
 517                         while (ll && !has_interesting) {
 518                                 /* Lost this line from these parents;
 519                                  * who are they?  Are they the same?
 520                                  */
 521                                 this_diff = ll->parent_map;
 522                                 if (!same_diff)
 523                                         same_diff = this_diff;
 524                                 else if (same_diff != this_diff) {
 525                                         has_interesting = 1;
 526                                 }
 527                                 ll = ll->next;
 528                         }
 529                 }
 530
 531                 if (!has_interesting && same_diff != all_mask) {
 532                         /* This hunk is not that interesting after all */
 533                         for (j = hunk_begin; j < hunk_end; j++)
 534                                 sline[j].flag &= ~mark;
 535                 }
 536                 i = hunk_end;
 537         }
 538
 539         has_interesting = give_context(sline, cnt, num_parent);
 540         return has_interesting;
 541 }
 542
 543 static void show_parent_lno(struct sline *sline, unsigned long l0, unsigned long l1, int n, unsigned long null_context)
 544 {
 545         l0 = sline[l0].p_lno[n];
 546         l1 = sline[l1].p_lno[n];
 547         printf(" -%lu,%lu", l0, l1-l0-null_context);
 548 }
 549
 550 static int hunk_comment_line(const char *bol)
 551 {
 552         int ch;
 553
 554         if (!bol)
 555                 return 0;
 556         ch = *bol & 0xff;
 557         return (isalpha(ch) || ch == '_' || ch == '$');
 558 }
 559
 560 static void show_line_to_eol(const char *line, int len, const char *reset)
 561 {
 562         int saw_cr_at_eol = 0;
 563         if (len < 0)
 564                 len = strlen(line);
 565         saw_cr_at_eol = (len && line[len-1] == '\r');
 566
 567         printf("%.*s%s%s\n", len - saw_cr_at_eol, line,
 568                reset,
 569                saw_cr_at_eol ? "\r" : "");
 570 }
 571
 572 static void dump_sline(struct sline *sline, const char *line_prefix,
 573                        unsigned long cnt, int num_parent,
 574                        int use_color, int result_deleted)
 575 {
 576         unsigned long mark = (1UL<<num_parent);
 577         unsigned long no_pre_delete = (2UL<<num_parent);
 578         int i;
 579         unsigned long lno = 0;
 580         const char *c_frag = diff_get_color(use_color, DIFF_FRAGINFO);
 581         const char *c_func = diff_get_color(use_color, DIFF_FUNCINFO);
 582         const char *c_new = diff_get_color(use_color, DIFF_FILE_NEW);
 583         const char *c_old = diff_get_color(use_color, DIFF_FILE_OLD);
 584         const char *c_plain = diff_get_color(use_color, DIFF_PLAIN);
 585         const char *c_reset = diff_get_color(use_color, DIFF_RESET);
 586
 587         if (result_deleted)
 588                 return; /* result deleted */
 589
 590         while (1) {
 591                 unsigned long hunk_end;
 592                 unsigned long rlines;
 593                 const char *hunk_comment = NULL;
 594                 unsigned long null_context = 0;
 595
 596                 while (lno <= cnt && !(sline[lno].flag & mark)) {
 597                         if (hunk_comment_line(sline[lno].bol))
 598                                 hunk_comment = sline[lno].bol;
 599                         lno++;
 600                 }
 601                 if (cnt < lno)
 602                         break;
 603                 else {
 604                         for (hunk_end = lno + 1; hunk_end <= cnt; hunk_end++)
 605                                 if (!(sline[hunk_end].flag & mark))
 606                                         break;
 607                 }
 608                 rlines = hunk_end - lno;
 609                 if (cnt < hunk_end)
 610                         rlines--; /* pointing at the last delete hunk */
 611
 612                 if (!context) {
 613                         /*
 614                          * Even when running with --unified=0, all
 615                          * lines in the hunk needs to be processed in
 616                          * the loop below in order to show the
 617                          * deletion recorded in lost_head.  However,
 618                          * we do not want to show the resulting line
 619                          * with all blank context markers in such a
 620                          * case.  Compensate.
 621                          */
 622                         unsigned long j;
 623                         for (j = lno; j < hunk_end; j++)
 624                                 if (!(sline[j].flag & (mark-1)))
 625                                         null_context++;
 626                         rlines -= null_context;
 627                 }
 628
 629                 printf("%s%s", line_prefix, c_frag);
 630                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 631                 for (i = 0; i < num_parent; i++)
 632                         show_parent_lno(sline, lno, hunk_end, i, null_context);
 633                 printf(" +%lu,%lu ", lno+1, rlines);
 634                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 635
 636                 if (hunk_comment) {
 637                         int comment_end = 0;
 638                         for (i = 0; i < 40; i++) {
 639                                 int ch = hunk_comment[i] & 0xff;
 640                                 if (!ch || ch == '\n')
 641                                         break;
 642                                 if (!isspace(ch))
 643                                     comment_end = i;
 644                         }
 645                         if (comment_end)
 646                                 printf("%s%s %s%s", c_reset,
 647                                                     c_plain, c_reset,
 648                                                     c_func);
 649                         for (i = 0; i < comment_end; i++)
 650                                 putchar(hunk_comment[i]);
 651                 }
 652
 653                 printf("%s\n", c_reset);
 654                 while (lno < hunk_end) {
 655                         struct lline *ll;
 656                         int j;
 657                         unsigned long p_mask;
 658                         struct sline *sl = &sline[lno++];
 659                         ll = (sl->flag & no_pre_delete) ? NULL : sl->lost_head;
 660                         while (ll) {
 661                                 printf("%s%s", line_prefix, c_old);
 662                                 for (j = 0; j < num_parent; j++) {
 663                                         if (ll->parent_map & (1UL<<j))
 664                                                 putchar('-');
 665                                         else
 666                                                 putchar(' ');
 667                                 }
 668                                 show_line_to_eol(ll->line, -1, c_reset);
 669                                 ll = ll->next;
 670                         }
 671                         if (cnt < lno)
 672                                 break;
 673                         p_mask = 1;
 674                         fputs(line_prefix, stdout);
 675                         if (!(sl->flag & (mark-1))) {
 676                                 /*
 677                                  * This sline was here to hang the
 678                                  * lost lines in front of it.
 679                                  */
 680                                 if (!context)
 681                                         continue;
 682                                 fputs(c_plain, stdout);
 683                         }
 684                         else
 685                                 fputs(c_new, stdout);
 686                         for (j = 0; j < num_parent; j++) {
 687                                 if (p_mask & sl->flag)
 688                                         putchar('+');
 689                                 else
 690                                         putchar(' ');
 691                                 p_mask <<= 1;
 692                         }
 693                         show_line_to_eol(sl->bol, sl->len, c_reset);
 694                 }
 695         }
 696 }
 697
 698 static void reuse_combine_diff(struct sline *sline, unsigned long cnt,
 699                                int i, int j)
 700 {
 701         /* We have already examined parent j and we know parent i
 702          * and parent j are the same, so reuse the combined result
 703          * of parent j for parent i.
 704          */
 705         unsigned long lno, imask, jmask;
 706         imask = (1UL<<i);
 707         jmask = (1UL<<j);
 708
 709         for (lno = 0; lno <= cnt; lno++) {
 710                 struct lline *ll = sline->lost_head;
 711                 sline->p_lno[i] = sline->p_lno[j];
 712                 while (ll) {
 713                         if (ll->parent_map & jmask)
 714                                 ll->parent_map |= imask;
 715                         ll = ll->next;
 716                 }
 717                 if (sline->flag & jmask)
 718                         sline->flag |= imask;
 719                 sline++;
 720         }
 721         /* the overall size of the file (sline[cnt]) */
 722         sline->p_lno[i] = sline->p_lno[j];
 723 }
 724
 725 static void dump_quoted_path(const char *head,
 726                              const char *prefix,
 727                              const char *path,
 728                              const char *line_prefix,
 729                              const char *c_meta, const char *c_reset)
 730 {
 731         static struct strbuf buf = STRBUF_INIT;
 732
 733         strbuf_reset(&buf);
 734         strbuf_addstr(&buf, line_prefix);
 735         strbuf_addstr(&buf, c_meta);
 736         strbuf_addstr(&buf, head);
 737         quote_two_c_style(&buf, prefix, path, 0);
 738         strbuf_addstr(&buf, c_reset);
 739         puts(buf.buf);
 740 }
 741
 742 static void show_combined_header(struct combine_diff_path *elem,
 743                                  int num_parent,
 744                                  int dense,
 745                                  struct rev_info *rev,
 746                                  const char *line_prefix,
 747                                  int mode_differs,
 748                                  int show_file_header)
 749 {
 750         struct diff_options *opt = &rev->diffopt;
 751         int abbrev = DIFF_OPT_TST(opt, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
 752         const char *a_prefix = opt->a_prefix ? opt->a_prefix : "a/";
 753         const char *b_prefix = opt->b_prefix ? opt->b_prefix : "b/";
 754         const char *c_meta = diff_get_color_opt(opt, DIFF_METAINFO);
 755         const char *c_reset = diff_get_color_opt(opt, DIFF_RESET);
 756         const char *abb;
 757         int added = 0;
 758         int deleted = 0;
 759         int i;
 760
 761         if (rev->loginfo && !rev->no_commit_id)
 762                 show_log(rev);
 763
 764         dump_quoted_path(dense ? "diff --cc " : "diff --combined ",
 765                          "", elem->path, line_prefix, c_meta, c_reset);
 766         printf("%s%sindex ", line_prefix, c_meta);
 767         for (i = 0; i < num_parent; i++) {
 768                 abb = find_unique_abbrev(elem->parent[i].sha1,
 769                                          abbrev);
 770                 printf("%s%s", i ? "," : "", abb);
 771         }
 772         abb = find_unique_abbrev(elem->sha1, abbrev);
 773         printf("..%s%s\n", abb, c_reset);
 774
 775         if (mode_differs) {
 776                 deleted = !elem->mode;
 777
 778                 /* We say it was added if nobody had it */
 779                 added = !deleted;
 780                 for (i = 0; added && i < num_parent; i++)
 781                         if (elem->parent[i].status !=
 782                             DIFF_STATUS_ADDED)
 783                                 added = 0;
 784                 if (added)
 785                         printf("%s%snew file mode %06o",
 786                                line_prefix, c_meta, elem->mode);
 787                 else {
 788                         if (deleted)
 789                                 printf("%s%sdeleted file ",
 790                                        line_prefix, c_meta);
 791                         printf("mode ");
 792                         for (i = 0; i < num_parent; i++) {
 793                                 printf("%s%06o", i ? "," : "",
 794                                        elem->parent[i].mode);
 795                         }
 796                         if (elem->mode)
 797                                 printf("..%06o", elem->mode);
 798                 }
 799                 printf("%s\n", c_reset);
 800         }
 801
 802         if (!show_file_header)
 803                 return;
 804
 805         if (added)
 806                 dump_quoted_path("--- ", "", "/dev/null",
 807                                  line_prefix, c_meta, c_reset);
 808         else
 809                 dump_quoted_path("--- ", a_prefix, elem->path,
 810                                  line_prefix, c_meta, c_reset);
 811         if (deleted)
 812                 dump_quoted_path("+++ ", "", "/dev/null",
 813                                  line_prefix, c_meta, c_reset);
 814         else
 815                 dump_quoted_path("+++ ", b_prefix, elem->path,
 816                                  line_prefix, c_meta, c_reset);
 817 }
 818
 819 static void show_patch_diff(struct combine_diff_path *elem, int num_parent,
 820                             int dense, int working_tree_file,
 821                             struct rev_info *rev)
 822 {
 823         struct diff_options *opt = &rev->diffopt;
 824         unsigned long result_size, cnt, lno;
 825         int result_deleted = 0;
 826         char *result, *cp;
 827         struct sline *sline; /* survived lines */
 828         int mode_differs = 0;
 829         int i, show_hunks;
 830         mmfile_t result_file;
 831         struct userdiff_driver *userdiff;
 832         struct userdiff_driver *textconv = NULL;
 833         int is_binary;
 834         const char *line_prefix = diff_line_prefix(opt);
 835
 836         context = opt->context;
 837         userdiff = userdiff_find_by_path(elem->path);
 838         if (!userdiff)
 839                 userdiff = userdiff_find_by_name("default");
 840         if (DIFF_OPT_TST(opt, ALLOW_TEXTCONV))
 841                 textconv = userdiff_get_textconv(userdiff);
 842
 843         /* Read the result of merge first */
 844         if (!working_tree_file)
 845                 result = grab_blob(elem->sha1, elem->mode, &result_size,
 846                                    textconv, elem->path);
 847         else {
 848                 /* Used by diff-tree to read from the working tree */
 849                 struct stat st;
 850                 int fd = -1;
 851
 852                 if (lstat(elem->path, &st) < 0)
 853                         goto deleted_file;
 854
 855                 if (S_ISLNK(st.st_mode)) {
 856                         struct strbuf buf = STRBUF_INIT;
 857
 858                         if (strbuf_readlink(&buf, elem->path, st.st_size) < 0) {
 859                                 error("readlink(%s): %s", elem->path,
 860                                       strerror(errno));
 861                                 return;
 862                         }
 863                         result_size = buf.len;
 864                         result = strbuf_detach(&buf, NULL);
 865                         elem->mode = canon_mode(st.st_mode);
 866                 } else if (S_ISDIR(st.st_mode)) {
 867                         unsigned char sha1[20];
 868                         if (resolve_gitlink_ref(elem->path, "HEAD", sha1) < 0)
 869                                 result = grab_blob(elem->sha1, elem->mode,
 870                                                    &result_size, NULL, NULL);
 871                         else
 872                                 result = grab_blob(sha1, elem->mode,
 873                                                    &result_size, NULL, NULL);
 874                 } else if (textconv) {
 875                         struct diff_filespec *df = alloc_filespec(elem->path);
 876                         fill_filespec(df, null_sha1, 0, st.st_mode);
 877                         result_size = fill_textconv(textconv, df, &result);
 878                         free_filespec(df);
 879                 } else if (0 <= (fd = open(elem->path, O_RDONLY))) {
 880                         size_t len = xsize_t(st.st_size);
 881                         ssize_t done;
 882                         int is_file, i;
 883
 884                         elem->mode = canon_mode(st.st_mode);
 885                         /* if symlinks don't work, assume symlink if all parents
 886                          * are symlinks
 887                          */
 888                         is_file = has_symlinks;
 889                         for (i = 0; !is_file && i < num_parent; i++)
 890                                 is_file = !S_ISLNK(elem->parent[i].mode);
 891                         if (!is_file)
 892                                 elem->mode = canon_mode(S_IFLNK);
 893
 894                         result_size = len;
 895                         result = xmalloc(len + 1);
 896
 897                         done = read_in_full(fd, result, len);
 898                         if (done < 0)
 899                                 die_errno("read error '%s'", elem->path);
 900                         else if (done < len)
 901                                 die("early EOF '%s'", elem->path);
 902
 903                         result[len] = 0;
 904
 905                         /* If not a fake symlink, apply filters, e.g. autocrlf */
 906                         if (is_file) {
 907                                 struct strbuf buf = STRBUF_INIT;
 908
 909                                 if (convert_to_git(elem->path, result, len, &buf, safe_crlf)) {
 910                                         free(result);
 911                                         result = strbuf_detach(&buf, &len);
 912                                         result_size = len;
 913                                 }
 914                         }
 915                 }
 916                 else {
 917                 deleted_file:
 918                         result_deleted = 1;
 919                         result_size = 0;
 920                         elem->mode = 0;
 921                         result = xcalloc(1, 1);
 922                 }
 923
 924                 if (0 <= fd)
 925                         close(fd);
 926         }
 927
 928         for (i = 0; i < num_parent; i++) {
 929                 if (elem->parent[i].mode != elem->mode) {
 930                         mode_differs = 1;
 931                         break;
 932                 }
 933         }
 934
 935         if (textconv)
 936                 is_binary = 0;
 937         else if (userdiff->binary != -1)
 938                 is_binary = userdiff->binary;
 939         else {
 940                 is_binary = buffer_is_binary(result, result_size);
 941                 for (i = 0; !is_binary && i < num_parent; i++) {
 942                         char *buf;
 943                         unsigned long size;
 944                         buf = grab_blob(elem->parent[i].sha1,
 945                                         elem->parent[i].mode,
 946                                         &size, NULL, NULL);
 947                         if (buffer_is_binary(buf, size))
 948                                 is_binary = 1;
 949                         free(buf);
 950                 }
 951         }
 952         if (is_binary) {
 953                 show_combined_header(elem, num_parent, dense, rev,
 954                                      line_prefix, mode_differs, 0);
 955                 printf("Binary files differ\n");
 956                 free(result);
 957                 return;
 958         }
 959
 960         for (cnt = 0, cp = result; cp < result + result_size; cp++) {
 961                 if (*cp == '\n')
 962                         cnt++;
 963         }
 964         if (result_size && result[result_size-1] != '\n')
 965                 cnt++; /* incomplete line */
 966
 967         sline = xcalloc(cnt+2, sizeof(*sline));
 968         sline[0].bol = result;
 969         for (lno = 0; lno <= cnt + 1; lno++) {
 970                 sline[lno].lost_tail = &sline[lno].lost_head;
 971                 sline[lno].flag = 0;
 972         }
 973         for (lno = 0, cp = result; cp < result + result_size; cp++) {
 974                 if (*cp == '\n') {
 975                         sline[lno].len = cp - sline[lno].bol;
 976                         lno++;
 977                         if (lno < cnt)
 978                                 sline[lno].bol = cp + 1;
 979                 }
 980         }
 981         if (result_size && result[result_size-1] != '\n')
 982                 sline[cnt-1].len = result_size - (sline[cnt-1].bol - result);
 983
 984         result_file.ptr = result;
 985         result_file.size = result_size;
 986
 987         /* Even p_lno[cnt+1] is valid -- that is for the end line number
 988          * for deletion hunk at the end.
 989          */
 990         sline[0].p_lno = xcalloc((cnt+2) * num_parent, sizeof(unsigned long));
 991         for (lno = 0; lno <= cnt; lno++)
 992                 sline[lno+1].p_lno = sline[lno].p_lno + num_parent;
 993
 994         for (i = 0; i < num_parent; i++) {
 995                 int j;
 996                 for (j = 0; j < i; j++) {
 997                         if (!hashcmp(elem->parent[i].sha1,
 998                                      elem->parent[j].sha1)) {
 999                                 reuse_combine_diff(sline, cnt, i, j);
1000                                 break;
1001                         }
1002                 }
1003                 if (i <= j)
1004                         combine_diff(elem->parent[i].sha1,
1005                                      elem->parent[i].mode,
1006                                      &result_file, sline,
1007                                      cnt, i, num_parent, result_deleted,
1008                                      textconv, elem->path, opt->xdl_opts);
1009         }
1010
1011         show_hunks = make_hunks(sline, cnt, num_parent, dense);
1012
1013         if (show_hunks || mode_differs || working_tree_file) {
1014                 show_combined_header(elem, num_parent, dense, rev,
1015                                      line_prefix, mode_differs, 1);
1016                 dump_sline(sline, line_prefix, cnt, num_parent,
1017                            opt->use_color, result_deleted);
1018         }
1019         free(result);
1020
1021         for (lno = 0; lno < cnt; lno++) {
1022                 if (sline[lno].lost_head) {
1023                         struct lline *ll = sline[lno].lost_head;
1024                         while (ll) {
1025                                 struct lline *tmp = ll;
1026                                 ll = ll->next;
1027                                 free(tmp);
1028                         }
1029                 }
1030         }
1031         free(sline[0].p_lno);
1032         free(sline);
1033 }
1034
1035 static void show_raw_diff(struct combine_diff_path *p, int num_parent, struct rev_info *rev)
1036 {
1037         struct diff_options *opt = &rev->diffopt;
1038         int line_termination, inter_name_termination, i;
1039         const char *line_prefix = diff_line_prefix(opt);
1040
1041         line_termination = opt->line_termination;
1042         inter_name_termination = '\t';
1043         if (!line_termination)
1044                 inter_name_termination = 0;
1045
1046         if (rev->loginfo && !rev->no_commit_id)
1047                 show_log(rev);
1048
1049
1050         if (opt->output_format & DIFF_FORMAT_RAW) {
1051                 printf("%s", line_prefix);
1052
1053                 /* As many colons as there are parents */
1054                 for (i = 0; i < num_parent; i++)
1055                         putchar(':');
1056
1057                 /* Show the modes */
1058                 for (i = 0; i < num_parent; i++)
1059                         printf("%06o ", p->parent[i].mode);
1060                 printf("%06o", p->mode);
1061
1062                 /* Show sha1's */
1063                 for (i = 0; i < num_parent; i++)
1064                         printf(" %s", diff_unique_abbrev(p->parent[i].sha1,
1065                                                          opt->abbrev));
1066                 printf(" %s ", diff_unique_abbrev(p->sha1, opt->abbrev));
1067         }
1068
1069         if (opt->output_format & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS)) {
1070                 for (i = 0; i < num_parent; i++)
1071                         putchar(p->parent[i].status);
1072                 putchar(inter_name_termination);
1073         }
1074
1075         write_name_quoted(p->path, stdout, line_termination);
1076 }
1077
1078 /*
1079  * The result (p->elem) is from the working tree and their
1080  * parents are typically from multiple stages during a merge
1081  * (i.e. diff-files) or the state in HEAD and in the index
1082  * (i.e. diff-index).
1083  */
1084 void show_combined_diff(struct combine_diff_path *p,
1085                        int num_parent,
1086                        int dense,
1087                        struct rev_info *rev)
1088 {
1089         struct diff_options *opt = &rev->diffopt;
1090
1091         if (!p->len)
1092                 return;
1093         if (opt->output_format & (DIFF_FORMAT_RAW |
1094                                   DIFF_FORMAT_NAME |
1095                                   DIFF_FORMAT_NAME_STATUS))
1096                 show_raw_diff(p, num_parent, rev);
1097         else if (opt->output_format & DIFF_FORMAT_PATCH)
1098                 show_patch_diff(p, num_parent, dense, 1, rev);
1099 }
1100
1101 static void free_combined_pair(struct diff_filepair *pair)
1102 {
1103         free(pair->two);
1104         free(pair);
1105 }
1106
1107 /*
1108  * A combine_diff_path expresses N parents on the LHS against 1 merge
1109  * result. Synthesize a diff_filepair that has N entries on the "one"
1110  * side and 1 entry on the "two" side.
1111  *
1112  * In the future, we might want to add more data to combine_diff_path
1113  * so that we can fill fields we are ignoring (most notably, size) here,
1114  * but currently nobody uses it, so this should suffice for now.
1115  */
1116 static struct diff_filepair *combined_pair(struct combine_diff_path *p,
1117                                            int num_parent)
1118 {
1119         int i;
1120         struct diff_filepair *pair;
1121         struct diff_filespec *pool;
1122
1123         pair = xmalloc(sizeof(*pair));
1124         pool = xcalloc(num_parent + 1, sizeof(struct diff_filespec));
1125         pair->one = pool + 1;
1126         pair->two = pool;
1127
1128         for (i = 0; i < num_parent; i++) {
1129                 pair->one[i].path = p->path;
1130                 pair->one[i].mode = p->parent[i].mode;
1131                 hashcpy(pair->one[i].sha1, p->parent[i].sha1);
1132                 pair->one[i].sha1_valid = !is_null_sha1(p->parent[i].sha1);
1133                 pair->one[i].has_more_entries = 1;
1134         }
1135         pair->one[num_parent - 1].has_more_entries = 0;
1136
1137         pair->two->path = p->path;
1138         pair->two->mode = p->mode;
1139         hashcpy(pair->two->sha1, p->sha1);
1140         pair->two->sha1_valid = !is_null_sha1(p->sha1);
1141         return pair;
1142 }
1143
1144 static void handle_combined_callback(struct diff_options *opt,
1145                                      struct combine_diff_path *paths,
1146                                      int num_parent,
1147                                      int num_paths)
1148 {
1149         struct combine_diff_path *p;
1150         struct diff_queue_struct q;
1151         int i;
1152
1153         q.queue = xcalloc(num_paths, sizeof(struct diff_filepair *));
1154         q.alloc = num_paths;
1155         q.nr = num_paths;
1156         for (i = 0, p = paths; p; p = p->next) {
1157                 if (!p->len)
1158                         continue;
1159                 q.queue[i++] = combined_pair(p, num_parent);
1160         }
1161         opt->format_callback(&q, opt, opt->format_callback_data);
1162         for (i = 0; i < num_paths; i++)
1163                 free_combined_pair(q.queue[i]);
1164         free(q.queue);
1165 }
1166
1167 void diff_tree_combined(const unsigned char *sha1,
1168                         const struct sha1_array *parents,
1169                         int dense,
1170                         struct rev_info *rev)
1171 {
1172         struct diff_options *opt = &rev->diffopt;
1173         struct diff_options diffopts;
1174         struct combine_diff_path *p, *paths = NULL;
1175         int i, num_paths, needsep, show_log_first, num_parent = parents->nr;
1176
1177         diffopts = *opt;
1178         diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
1179         DIFF_OPT_SET(&diffopts, RECURSIVE);
1180         DIFF_OPT_CLR(&diffopts, ALLOW_EXTERNAL);
1181
1182         show_log_first = !!rev->loginfo && !rev->no_commit_id;
1183         needsep = 0;
1184         /* find set of paths that everybody touches */
1185         for (i = 0; i < num_parent; i++) {
1186                 /* show stat against the first parent even
1187                  * when doing combined diff.
1188                  */
1189                 int stat_opt = (opt->output_format &
1190                                 (DIFF_FORMAT_NUMSTAT|DIFF_FORMAT_DIFFSTAT));
1191                 if (i == 0 && stat_opt)
1192                         diffopts.output_format = stat_opt;
1193                 else
1194                         diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
1195                 diff_tree_sha1(parents->sha1[i], sha1, "", &diffopts);
1196                 diffcore_std(&diffopts);
1197                 paths = intersect_paths(paths, i, num_parent);
1198
1199                 if (show_log_first && i == 0) {
1200                         show_log(rev);
1201
1202                         if (rev->verbose_header && opt->output_format)
1203                                 printf("%s%c", diff_line_prefix(opt),
1204                                        opt->line_termination);
1205                 }
1206                 diff_flush(&diffopts);
1207         }
1208
1209         /* find out surviving paths */
1210         for (num_paths = 0, p = paths; p; p = p->next) {
1211                 if (p->len)
1212                         num_paths++;
1213         }
1214         if (num_paths) {
1215                 if (opt->output_format & (DIFF_FORMAT_RAW |
1216                                           DIFF_FORMAT_NAME |
1217                                           DIFF_FORMAT_NAME_STATUS)) {
1218                         for (p = paths; p; p = p->next) {
1219                                 if (p->len)
1220                                         show_raw_diff(p, num_parent, rev);
1221                         }
1222                         needsep = 1;
1223                 }
1224                 else if (opt->output_format &
1225                          (DIFF_FORMAT_NUMSTAT|DIFF_FORMAT_DIFFSTAT))
1226                         needsep = 1;
1227                 else if (opt->output_format & DIFF_FORMAT_CALLBACK)
1228                         handle_combined_callback(opt, paths, num_parent, num_paths);
1229
1230                 if (opt->output_format & DIFF_FORMAT_PATCH) {
1231                         if (needsep)
1232                                 printf("%s%c", diff_line_prefix(opt),
1233                                        opt->line_termination);
1234                         for (p = paths; p; p = p->next) {
1235                                 if (p->len)
1236                                         show_patch_diff(p, num_parent, dense,
1237                                                         0, rev);
1238                         }
1239                 }
1240         }
1241
1242         /* Clean things up */
1243         while (paths) {
1244                 struct combine_diff_path *tmp = paths;
1245                 paths = paths->next;
1246                 free(tmp);
1247         }
1248 }
1249
1250 void diff_tree_combined_merge(const struct commit *commit, int dense,
1251                               struct rev_info *rev)
1252 {
1253         struct commit_list *parent = commit->parents;
1254         struct sha1_array parents = SHA1_ARRAY_INIT;
1255
1256         while (parent) {
1257                 sha1_array_append(&parents, parent->item->object.sha1);
1258                 parent = parent->next;
1259         }
1260         diff_tree_combined(commit->object.sha1, &parents, dense, rev);
1261         sha1_array_clear(&parents);
1262 }