combine-diff.con commit archive: declare struct archiver where it's needed (f15f736)
   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
  10static struct combine_diff_path *intersect_paths(struct combine_diff_path *curr, int n, int num_parent)
  11{
  12        struct diff_queue_struct *q = &diff_queued_diff;
  13        struct combine_diff_path *p;
  14        int i;
  15
  16        if (!n) {
  17                struct combine_diff_path *list = NULL, **tail = &list;
  18                for (i = 0; i < q->nr; i++) {
  19                        int len;
  20                        const char *path;
  21                        if (diff_unmodified_pair(q->queue[i]))
  22                                continue;
  23                        path = q->queue[i]->two->path;
  24                        len = strlen(path);
  25                        p = xmalloc(combine_diff_path_size(num_parent, len));
  26                        p->path = (char*) &(p->parent[num_parent]);
  27                        memcpy(p->path, path, len);
  28                        p->path[len] = 0;
  29                        p->len = len;
  30                        p->next = NULL;
  31                        memset(p->parent, 0,
  32                               sizeof(p->parent[0]) * num_parent);
  33
  34                        hashcpy(p->sha1, q->queue[i]->two->sha1);
  35                        p->mode = q->queue[i]->two->mode;
  36                        hashcpy(p->parent[n].sha1, q->queue[i]->one->sha1);
  37                        p->parent[n].mode = q->queue[i]->one->mode;
  38                        p->parent[n].status = q->queue[i]->status;
  39                        *tail = p;
  40                        tail = &p->next;
  41                }
  42                return list;
  43        }
  44
  45        for (p = curr; p; p = p->next) {
  46                int found = 0;
  47                if (!p->len)
  48                        continue;
  49                for (i = 0; i < q->nr; i++) {
  50                        const char *path;
  51                        int len;
  52
  53                        if (diff_unmodified_pair(q->queue[i]))
  54                                continue;
  55                        path = q->queue[i]->two->path;
  56                        len = strlen(path);
  57                        if (len == p->len && !memcmp(path, p->path, len)) {
  58                                found = 1;
  59                                hashcpy(p->parent[n].sha1, q->queue[i]->one->sha1);
  60                                p->parent[n].mode = q->queue[i]->one->mode;
  61                                p->parent[n].status = q->queue[i]->status;
  62                                break;
  63                        }
  64                }
  65                if (!found)
  66                        p->len = 0;
  67        }
  68        return curr;
  69}
  70
  71/* Lines lost from parent */
  72struct lline {
  73        struct lline *next;
  74        int len;
  75        unsigned long parent_map;
  76        char line[FLEX_ARRAY];
  77};
  78
  79/* Lines surviving in the merge result */
  80struct sline {
  81        struct lline *lost_head, **lost_tail;
  82        char *bol;
  83        int len;
  84        /* bit 0 up to (N-1) are on if the parent has this line (i.e.
  85         * we did not change it).
  86         * bit N is used for "interesting" lines, including context.
  87         * bit (N+1) is used for "do not show deletion before this".
  88         */
  89        unsigned long flag;
  90        unsigned long *p_lno;
  91};
  92
  93static char *grab_blob(const unsigned char *sha1, unsigned long *size)
  94{
  95        char *blob;
  96        enum object_type type;
  97        if (is_null_sha1(sha1)) {
  98                /* deleted blob */
  99                *size = 0;
 100                return xcalloc(1, 1);
 101        }
 102        blob = read_sha1_file(sha1, &type, size);
 103        if (type != OBJ_BLOB)
 104                die("object '%s' is not a blob!", sha1_to_hex(sha1));
 105        return blob;
 106}
 107
 108static void append_lost(struct sline *sline, int n, const char *line, int len)
 109{
 110        struct lline *lline;
 111        unsigned long this_mask = (1UL<<n);
 112        if (line[len-1] == '\n')
 113                len--;
 114
 115        /* Check to see if we can squash things */
 116        if (sline->lost_head) {
 117                struct lline *last_one = NULL;
 118                /* We cannot squash it with earlier one */
 119                for (lline = sline->lost_head;
 120                     lline;
 121                     lline = lline->next)
 122                        if (lline->parent_map & this_mask)
 123                                last_one = lline;
 124                lline = last_one ? last_one->next : sline->lost_head;
 125                while (lline) {
 126                        if (lline->len == len &&
 127                            !memcmp(lline->line, line, len)) {
 128                                lline->parent_map |= this_mask;
 129                                return;
 130                        }
 131                        lline = lline->next;
 132                }
 133        }
 134
 135        lline = xmalloc(sizeof(*lline) + len + 1);
 136        lline->len = len;
 137        lline->next = NULL;
 138        lline->parent_map = this_mask;
 139        memcpy(lline->line, line, len);
 140        lline->line[len] = 0;
 141        *sline->lost_tail = lline;
 142        sline->lost_tail = &lline->next;
 143}
 144
 145struct combine_diff_state {
 146        struct xdiff_emit_state xm;
 147
 148        unsigned int lno;
 149        int ob, on, nb, nn;
 150        unsigned long nmask;
 151        int num_parent;
 152        int n;
 153        struct sline *sline;
 154        struct sline *lost_bucket;
 155};
 156
 157static void consume_line(void *state_, char *line, unsigned long len)
 158{
 159        struct combine_diff_state *state = state_;
 160        if (5 < len && !memcmp("@@ -", line, 4)) {
 161                if (parse_hunk_header(line, len,
 162                                      &state->ob, &state->on,
 163                                      &state->nb, &state->nn))
 164                        return;
 165                state->lno = state->nb;
 166                if (!state->nb)
 167                        /* @@ -1,2 +0,0 @@ to remove the
 168                         * first two lines...
 169                         */
 170                        state->nb = 1;
 171                if (state->nn == 0)
 172                        /* @@ -X,Y +N,0 @@ removed Y lines
 173                         * that would have come *after* line N
 174                         * in the result.  Our lost buckets hang
 175                         * to the line after the removed lines,
 176                         */
 177                        state->lost_bucket = &state->sline[state->nb];
 178                else
 179                        state->lost_bucket = &state->sline[state->nb-1];
 180                if (!state->sline[state->nb-1].p_lno)
 181                        state->sline[state->nb-1].p_lno =
 182                                xcalloc(state->num_parent,
 183                                        sizeof(unsigned long));
 184                state->sline[state->nb-1].p_lno[state->n] = state->ob;
 185                return;
 186        }
 187        if (!state->lost_bucket)
 188                return; /* not in any hunk yet */
 189        switch (line[0]) {
 190        case '-':
 191                append_lost(state->lost_bucket, state->n, line+1, len-1);
 192                break;
 193        case '+':
 194                state->sline[state->lno-1].flag |= state->nmask;
 195                state->lno++;
 196                break;
 197        }
 198}
 199
 200static void combine_diff(const unsigned char *parent, mmfile_t *result_file,
 201                         struct sline *sline, unsigned int cnt, int n,
 202                         int num_parent)
 203{
 204        unsigned int p_lno, lno;
 205        unsigned long nmask = (1UL << n);
 206        xpparam_t xpp;
 207        xdemitconf_t xecfg;
 208        mmfile_t parent_file;
 209        xdemitcb_t ecb;
 210        struct combine_diff_state state;
 211        unsigned long sz;
 212
 213        if (!cnt)
 214                return; /* result deleted */
 215
 216        parent_file.ptr = grab_blob(parent, &sz);
 217        parent_file.size = sz;
 218        xpp.flags = XDF_NEED_MINIMAL;
 219        memset(&xecfg, 0, sizeof(xecfg));
 220        ecb.outf = xdiff_outf;
 221        ecb.priv = &state;
 222        memset(&state, 0, sizeof(state));
 223        state.xm.consume = consume_line;
 224        state.nmask = nmask;
 225        state.sline = sline;
 226        state.lno = 1;
 227        state.num_parent = num_parent;
 228        state.n = n;
 229
 230        xdi_diff(&parent_file, result_file, &xpp, &xecfg, &ecb);
 231        free(parent_file.ptr);
 232
 233        /* Assign line numbers for this parent.
 234         *
 235         * sline[lno].p_lno[n] records the first line number
 236         * (counting from 1) for parent N if the final hunk display
 237         * started by showing sline[lno] (possibly showing the lost
 238         * lines attached to it first).
 239         */
 240        for (lno = 0,  p_lno = 1; lno <= cnt; lno++) {
 241                struct lline *ll;
 242                sline[lno].p_lno[n] = p_lno;
 243
 244                /* How many lines would this sline advance the p_lno? */
 245                ll = sline[lno].lost_head;
 246                while (ll) {
 247                        if (ll->parent_map & nmask)
 248                                p_lno++; /* '-' means parent had it */
 249                        ll = ll->next;
 250                }
 251                if (lno < cnt && !(sline[lno].flag & nmask))
 252                        p_lno++; /* no '+' means parent had it */
 253        }
 254        sline[lno].p_lno[n] = p_lno; /* trailer */
 255}
 256
 257static unsigned long context = 3;
 258static char combine_marker = '@';
 259
 260static int interesting(struct sline *sline, unsigned long all_mask)
 261{
 262        /* If some parents lost lines here, or if we have added to
 263         * some parent, it is interesting.
 264         */
 265        return ((sline->flag & all_mask) || sline->lost_head);
 266}
 267
 268static unsigned long adjust_hunk_tail(struct sline *sline,
 269                                      unsigned long all_mask,
 270                                      unsigned long hunk_begin,
 271                                      unsigned long i)
 272{
 273        /* i points at the first uninteresting line.  If the last line
 274         * of the hunk was interesting only because it has some
 275         * deletion, then it is not all that interesting for the
 276         * purpose of giving trailing context lines.  This is because
 277         * we output '-' line and then unmodified sline[i-1] itself in
 278         * that case which gives us one extra context line.
 279         */
 280        if ((hunk_begin + 1 <= i) && !(sline[i-1].flag & all_mask))
 281                i--;
 282        return i;
 283}
 284
 285static unsigned long find_next(struct sline *sline,
 286                               unsigned long mark,
 287                               unsigned long i,
 288                               unsigned long cnt,
 289                               int look_for_uninteresting)
 290{
 291        /* We have examined up to i-1 and are about to look at i.
 292         * Find next interesting or uninteresting line.  Here,
 293         * "interesting" does not mean interesting(), but marked by
 294         * the give_context() function below (i.e. it includes context
 295         * lines that are not interesting to interesting() function
 296         * that are surrounded by interesting() ones.
 297         */
 298        while (i <= cnt)
 299                if (look_for_uninteresting
 300                    ? !(sline[i].flag & mark)
 301                    : (sline[i].flag & mark))
 302                        return i;
 303                else
 304                        i++;
 305        return i;
 306}
 307
 308static int give_context(struct sline *sline, unsigned long cnt, int num_parent)
 309{
 310        unsigned long all_mask = (1UL<<num_parent) - 1;
 311        unsigned long mark = (1UL<<num_parent);
 312        unsigned long no_pre_delete = (2UL<<num_parent);
 313        unsigned long i;
 314
 315        /* Two groups of interesting lines may have a short gap of
 316         * uninteresting lines.  Connect such groups to give them a
 317         * bit of context.
 318         *
 319         * We first start from what the interesting() function says,
 320         * and mark them with "mark", and paint context lines with the
 321         * mark.  So interesting() would still say false for such context
 322         * lines but they are treated as "interesting" in the end.
 323         */
 324        i = find_next(sline, mark, 0, cnt, 0);
 325        if (cnt < i)
 326                return 0;
 327
 328        while (i <= cnt) {
 329                unsigned long j = (context < i) ? (i - context) : 0;
 330                unsigned long k;
 331
 332                /* Paint a few lines before the first interesting line. */
 333                while (j < i)
 334                        sline[j++].flag |= mark | no_pre_delete;
 335
 336        again:
 337                /* we know up to i is to be included.  where does the
 338                 * next uninteresting one start?
 339                 */
 340                j = find_next(sline, mark, i, cnt, 1);
 341                if (cnt < j)
 342                        break; /* the rest are all interesting */
 343
 344                /* lookahead context lines */
 345                k = find_next(sline, mark, j, cnt, 0);
 346                j = adjust_hunk_tail(sline, all_mask, i, j);
 347
 348                if (k < j + context) {
 349                        /* k is interesting and [j,k) are not, but
 350                         * paint them interesting because the gap is small.
 351                         */
 352                        while (j < k)
 353                                sline[j++].flag |= mark;
 354                        i = k;
 355                        goto again;
 356                }
 357
 358                /* j is the first uninteresting line and there is
 359                 * no overlap beyond it within context lines.  Paint
 360                 * the trailing edge a bit.
 361                 */
 362                i = k;
 363                k = (j + context < cnt+1) ? j + context : cnt+1;
 364                while (j < k)
 365                        sline[j++].flag |= mark;
 366        }
 367        return 1;
 368}
 369
 370static int make_hunks(struct sline *sline, unsigned long cnt,
 371                       int num_parent, int dense)
 372{
 373        unsigned long all_mask = (1UL<<num_parent) - 1;
 374        unsigned long mark = (1UL<<num_parent);
 375        unsigned long i;
 376        int has_interesting = 0;
 377
 378        for (i = 0; i <= cnt; i++) {
 379                if (interesting(&sline[i], all_mask))
 380                        sline[i].flag |= mark;
 381                else
 382                        sline[i].flag &= ~mark;
 383        }
 384        if (!dense)
 385                return give_context(sline, cnt, num_parent);
 386
 387        /* Look at each hunk, and if we have changes from only one
 388         * parent, or the changes are the same from all but one
 389         * parent, mark that uninteresting.
 390         */
 391        i = 0;
 392        while (i <= cnt) {
 393                unsigned long j, hunk_begin, hunk_end;
 394                unsigned long same_diff;
 395                while (i <= cnt && !(sline[i].flag & mark))
 396                        i++;
 397                if (cnt < i)
 398                        break; /* No more interesting hunks */
 399                hunk_begin = i;
 400                for (j = i + 1; j <= cnt; j++) {
 401                        if (!(sline[j].flag & mark)) {
 402                                /* Look beyond the end to see if there
 403                                 * is an interesting line after this
 404                                 * hunk within context span.
 405                                 */
 406                                unsigned long la; /* lookahead */
 407                                int contin = 0;
 408                                la = adjust_hunk_tail(sline, all_mask,
 409                                                     hunk_begin, j);
 410                                la = (la + context < cnt + 1) ?
 411                                        (la + context) : cnt + 1;
 412                                while (j <= --la) {
 413                                        if (sline[la].flag & mark) {
 414                                                contin = 1;
 415                                                break;
 416                                        }
 417                                }
 418                                if (!contin)
 419                                        break;
 420                                j = la;
 421                        }
 422                }
 423                hunk_end = j;
 424
 425                /* [i..hunk_end) are interesting.  Now is it really
 426                 * interesting?  We check if there are only two versions
 427                 * and the result matches one of them.  That is, we look
 428                 * at:
 429                 *   (+) line, which records lines added to which parents;
 430                 *       this line appears in the result.
 431                 *   (-) line, which records from what parents the line
 432                 *       was removed; this line does not appear in the result.
 433                 * then check the set of parents the result has difference
 434                 * from, from all lines.  If there are lines that has
 435                 * different set of parents that the result has differences
 436                 * from, that means we have more than two versions.
 437                 *
 438                 * Even when we have only two versions, if the result does
 439                 * not match any of the parents, the it should be considered
 440                 * interesting.  In such a case, we would have all '+' line.
 441                 * After passing the above "two versions" test, that would
 442                 * appear as "the same set of parents" to be "all parents".
 443                 */
 444                same_diff = 0;
 445                has_interesting = 0;
 446                for (j = i; j < hunk_end && !has_interesting; j++) {
 447                        unsigned long this_diff = sline[j].flag & all_mask;
 448                        struct lline *ll = sline[j].lost_head;
 449                        if (this_diff) {
 450                                /* This has some changes.  Is it the
 451                                 * same as others?
 452                                 */
 453                                if (!same_diff)
 454                                        same_diff = this_diff;
 455                                else if (same_diff != this_diff) {
 456                                        has_interesting = 1;
 457                                        break;
 458                                }
 459                        }
 460                        while (ll && !has_interesting) {
 461                                /* Lost this line from these parents;
 462                                 * who are they?  Are they the same?
 463                                 */
 464                                this_diff = ll->parent_map;
 465                                if (!same_diff)
 466                                        same_diff = this_diff;
 467                                else if (same_diff != this_diff) {
 468                                        has_interesting = 1;
 469                                }
 470                                ll = ll->next;
 471                        }
 472                }
 473
 474                if (!has_interesting && same_diff != all_mask) {
 475                        /* This hunk is not that interesting after all */
 476                        for (j = hunk_begin; j < hunk_end; j++)
 477                                sline[j].flag &= ~mark;
 478                }
 479                i = hunk_end;
 480        }
 481
 482        has_interesting = give_context(sline, cnt, num_parent);
 483        return has_interesting;
 484}
 485
 486static void show_parent_lno(struct sline *sline, unsigned long l0, unsigned long l1, int n, unsigned long null_context)
 487{
 488        l0 = sline[l0].p_lno[n];
 489        l1 = sline[l1].p_lno[n];
 490        printf(" -%lu,%lu", l0, l1-l0-null_context);
 491}
 492
 493static int hunk_comment_line(const char *bol)
 494{
 495        int ch;
 496
 497        if (!bol)
 498                return 0;
 499        ch = *bol & 0xff;
 500        return (isalpha(ch) || ch == '_' || ch == '$');
 501}
 502
 503static void dump_sline(struct sline *sline, unsigned long cnt, int num_parent,
 504                       int use_color)
 505{
 506        unsigned long mark = (1UL<<num_parent);
 507        unsigned long no_pre_delete = (2UL<<num_parent);
 508        int i;
 509        unsigned long lno = 0;
 510        const char *c_frag = diff_get_color(use_color, DIFF_FRAGINFO);
 511        const char *c_new = diff_get_color(use_color, DIFF_FILE_NEW);
 512        const char *c_old = diff_get_color(use_color, DIFF_FILE_OLD);
 513        const char *c_plain = diff_get_color(use_color, DIFF_PLAIN);
 514        const char *c_reset = diff_get_color(use_color, DIFF_RESET);
 515
 516        if (!cnt)
 517                return; /* result deleted */
 518
 519        while (1) {
 520                struct sline *sl = &sline[lno];
 521                unsigned long hunk_end;
 522                unsigned long rlines;
 523                const char *hunk_comment = NULL;
 524                unsigned long null_context = 0;
 525
 526                while (lno <= cnt && !(sline[lno].flag & mark)) {
 527                        if (hunk_comment_line(sline[lno].bol))
 528                                hunk_comment = sline[lno].bol;
 529                        lno++;
 530                }
 531                if (cnt < lno)
 532                        break;
 533                else {
 534                        for (hunk_end = lno + 1; hunk_end <= cnt; hunk_end++)
 535                                if (!(sline[hunk_end].flag & mark))
 536                                        break;
 537                }
 538                rlines = hunk_end - lno;
 539                if (cnt < hunk_end)
 540                        rlines--; /* pointing at the last delete hunk */
 541
 542                if (!context) {
 543                        /*
 544                         * Even when running with --unified=0, all
 545                         * lines in the hunk needs to be processed in
 546                         * the loop below in order to show the
 547                         * deletion recorded in lost_head.  However,
 548                         * we do not want to show the resulting line
 549                         * with all blank context markers in such a
 550                         * case.  Compensate.
 551                         */
 552                        unsigned long j;
 553                        for (j = lno; j < hunk_end; j++)
 554                                if (!(sline[j].flag & (mark-1)))
 555                                        null_context++;
 556                        rlines -= null_context;
 557                }
 558
 559                fputs(c_frag, stdout);
 560                for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 561                for (i = 0; i < num_parent; i++)
 562                        show_parent_lno(sline, lno, hunk_end, i, null_context);
 563                printf(" +%lu,%lu ", lno+1, rlines);
 564                for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 565
 566                if (hunk_comment) {
 567                        int comment_end = 0;
 568                        for (i = 0; i < 40; i++) {
 569                                int ch = hunk_comment[i] & 0xff;
 570                                if (!ch || ch == '\n')
 571                                        break;
 572                                if (!isspace(ch))
 573                                    comment_end = i;
 574                        }
 575                        if (comment_end)
 576                                putchar(' ');
 577                        for (i = 0; i < comment_end; i++)
 578                                putchar(hunk_comment[i]);
 579                }
 580
 581                printf("%s\n", c_reset);
 582                while (lno < hunk_end) {
 583                        struct lline *ll;
 584                        int j;
 585                        unsigned long p_mask;
 586                        sl = &sline[lno++];
 587                        ll = (sl->flag & no_pre_delete) ? NULL : sl->lost_head;
 588                        while (ll) {
 589                                fputs(c_old, stdout);
 590                                for (j = 0; j < num_parent; j++) {
 591                                        if (ll->parent_map & (1UL<<j))
 592                                                putchar('-');
 593                                        else
 594                                                putchar(' ');
 595                                }
 596                                printf("%s%s\n", ll->line, c_reset);
 597                                ll = ll->next;
 598                        }
 599                        if (cnt < lno)
 600                                break;
 601                        p_mask = 1;
 602                        if (!(sl->flag & (mark-1))) {
 603                                /*
 604                                 * This sline was here to hang the
 605                                 * lost lines in front of it.
 606                                 */
 607                                if (!context)
 608                                        continue;
 609                                fputs(c_plain, stdout);
 610                        }
 611                        else
 612                                fputs(c_new, stdout);
 613                        for (j = 0; j < num_parent; j++) {
 614                                if (p_mask & sl->flag)
 615                                        putchar('+');
 616                                else
 617                                        putchar(' ');
 618                                p_mask <<= 1;
 619                        }
 620                        printf("%.*s%s\n", sl->len, sl->bol, c_reset);
 621                }
 622        }
 623}
 624
 625static void reuse_combine_diff(struct sline *sline, unsigned long cnt,
 626                               int i, int j)
 627{
 628        /* We have already examined parent j and we know parent i
 629         * and parent j are the same, so reuse the combined result
 630         * of parent j for parent i.
 631         */
 632        unsigned long lno, imask, jmask;
 633        imask = (1UL<<i);
 634        jmask = (1UL<<j);
 635
 636        for (lno = 0; lno <= cnt; lno++) {
 637                struct lline *ll = sline->lost_head;
 638                sline->p_lno[i] = sline->p_lno[j];
 639                while (ll) {
 640                        if (ll->parent_map & jmask)
 641                                ll->parent_map |= imask;
 642                        ll = ll->next;
 643                }
 644                if (sline->flag & jmask)
 645                        sline->flag |= imask;
 646                sline++;
 647        }
 648        /* the overall size of the file (sline[cnt]) */
 649        sline->p_lno[i] = sline->p_lno[j];
 650}
 651
 652static void dump_quoted_path(const char *head,
 653                             const char *prefix,
 654                             const char *path,
 655                             const char *c_meta, const char *c_reset)
 656{
 657        static struct strbuf buf = STRBUF_INIT;
 658
 659        strbuf_reset(&buf);
 660        strbuf_addstr(&buf, c_meta);
 661        strbuf_addstr(&buf, head);
 662        quote_two_c_style(&buf, prefix, path, 0);
 663        strbuf_addstr(&buf, c_reset);
 664        puts(buf.buf);
 665}
 666
 667static void show_patch_diff(struct combine_diff_path *elem, int num_parent,
 668                            int dense, struct rev_info *rev)
 669{
 670        struct diff_options *opt = &rev->diffopt;
 671        unsigned long result_size, cnt, lno;
 672        char *result, *cp;
 673        struct sline *sline; /* survived lines */
 674        int mode_differs = 0;
 675        int i, show_hunks;
 676        int working_tree_file = is_null_sha1(elem->sha1);
 677        int abbrev = DIFF_OPT_TST(opt, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
 678        mmfile_t result_file;
 679
 680        context = opt->context;
 681        /* Read the result of merge first */
 682        if (!working_tree_file)
 683                result = grab_blob(elem->sha1, &result_size);
 684        else {
 685                /* Used by diff-tree to read from the working tree */
 686                struct stat st;
 687                int fd = -1;
 688
 689                if (lstat(elem->path, &st) < 0)
 690                        goto deleted_file;
 691
 692                if (S_ISLNK(st.st_mode)) {
 693                        size_t len = xsize_t(st.st_size);
 694                        result_size = len;
 695                        result = xmalloc(len + 1);
 696                        if (result_size != readlink(elem->path, result, len)) {
 697                                error("readlink(%s): %s", elem->path,
 698                                      strerror(errno));
 699                                return;
 700                        }
 701                        result[len] = 0;
 702                        elem->mode = canon_mode(st.st_mode);
 703                }
 704                else if (0 <= (fd = open(elem->path, O_RDONLY)) &&
 705                         !fstat(fd, &st)) {
 706                        size_t len = xsize_t(st.st_size);
 707                        ssize_t done;
 708                        int is_file, i;
 709
 710                        elem->mode = canon_mode(st.st_mode);
 711                        /* if symlinks don't work, assume symlink if all parents
 712                         * are symlinks
 713                         */
 714                        is_file = has_symlinks;
 715                        for (i = 0; !is_file && i < num_parent; i++)
 716                                is_file = !S_ISLNK(elem->parent[i].mode);
 717                        if (!is_file)
 718                                elem->mode = canon_mode(S_IFLNK);
 719
 720                        result_size = len;
 721                        result = xmalloc(len + 1);
 722
 723                        done = read_in_full(fd, result, len);
 724                        if (done < 0)
 725                                die("read error '%s'", elem->path);
 726                        else if (done < len)
 727                                die("early EOF '%s'", elem->path);
 728
 729                        result[len] = 0;
 730                }
 731                else {
 732                deleted_file:
 733                        result_size = 0;
 734                        elem->mode = 0;
 735                        result = xcalloc(1, 1);
 736                }
 737
 738                if (0 <= fd)
 739                        close(fd);
 740        }
 741
 742        for (cnt = 0, cp = result; cp < result + result_size; cp++) {
 743                if (*cp == '\n')
 744                        cnt++;
 745        }
 746        if (result_size && result[result_size-1] != '\n')
 747                cnt++; /* incomplete line */
 748
 749        sline = xcalloc(cnt+2, sizeof(*sline));
 750        sline[0].bol = result;
 751        for (lno = 0; lno <= cnt + 1; lno++) {
 752                sline[lno].lost_tail = &sline[lno].lost_head;
 753                sline[lno].flag = 0;
 754        }
 755        for (lno = 0, cp = result; cp < result + result_size; cp++) {
 756                if (*cp == '\n') {
 757                        sline[lno].len = cp - sline[lno].bol;
 758                        lno++;
 759                        if (lno < cnt)
 760                                sline[lno].bol = cp + 1;
 761                }
 762        }
 763        if (result_size && result[result_size-1] != '\n')
 764                sline[cnt-1].len = result_size - (sline[cnt-1].bol - result);
 765
 766        result_file.ptr = result;
 767        result_file.size = result_size;
 768
 769        /* Even p_lno[cnt+1] is valid -- that is for the end line number
 770         * for deletion hunk at the end.
 771         */
 772        sline[0].p_lno = xcalloc((cnt+2) * num_parent, sizeof(unsigned long));
 773        for (lno = 0; lno <= cnt; lno++)
 774                sline[lno+1].p_lno = sline[lno].p_lno + num_parent;
 775
 776        for (i = 0; i < num_parent; i++) {
 777                int j;
 778                for (j = 0; j < i; j++) {
 779                        if (!hashcmp(elem->parent[i].sha1,
 780                                     elem->parent[j].sha1)) {
 781                                reuse_combine_diff(sline, cnt, i, j);
 782                                break;
 783                        }
 784                }
 785                if (i <= j)
 786                        combine_diff(elem->parent[i].sha1, &result_file, sline,
 787                                     cnt, i, num_parent);
 788                if (elem->parent[i].mode != elem->mode)
 789                        mode_differs = 1;
 790        }
 791
 792        show_hunks = make_hunks(sline, cnt, num_parent, dense);
 793
 794        if (show_hunks || mode_differs || working_tree_file) {
 795                const char *abb;
 796                int use_color = DIFF_OPT_TST(opt, COLOR_DIFF);
 797                const char *c_meta = diff_get_color(use_color, DIFF_METAINFO);
 798                const char *c_reset = diff_get_color(use_color, DIFF_RESET);
 799                int added = 0;
 800                int deleted = 0;
 801
 802                if (rev->loginfo && !rev->no_commit_id)
 803                        show_log(rev);
 804                dump_quoted_path(dense ? "diff --cc " : "diff --combined ",
 805                                 "", elem->path, c_meta, c_reset);
 806                printf("%sindex ", c_meta);
 807                for (i = 0; i < num_parent; i++) {
 808                        abb = find_unique_abbrev(elem->parent[i].sha1,
 809                                                 abbrev);
 810                        printf("%s%s", i ? "," : "", abb);
 811                }
 812                abb = find_unique_abbrev(elem->sha1, abbrev);
 813                printf("..%s%s\n", abb, c_reset);
 814
 815                if (mode_differs) {
 816                        deleted = !elem->mode;
 817
 818                        /* We say it was added if nobody had it */
 819                        added = !deleted;
 820                        for (i = 0; added && i < num_parent; i++)
 821                                if (elem->parent[i].status !=
 822                                    DIFF_STATUS_ADDED)
 823                                        added = 0;
 824                        if (added)
 825                                printf("%snew file mode %06o",
 826                                       c_meta, elem->mode);
 827                        else {
 828                                if (deleted)
 829                                        printf("%sdeleted file ", c_meta);
 830                                printf("mode ");
 831                                for (i = 0; i < num_parent; i++) {
 832                                        printf("%s%06o", i ? "," : "",
 833                                               elem->parent[i].mode);
 834                                }
 835                                if (elem->mode)
 836                                        printf("..%06o", elem->mode);
 837                        }
 838                        printf("%s\n", c_reset);
 839                }
 840                if (added)
 841                        dump_quoted_path("--- ", "", "/dev/null",
 842                                         c_meta, c_reset);
 843                else
 844                        dump_quoted_path("--- ", opt->a_prefix, elem->path,
 845                                         c_meta, c_reset);
 846                if (deleted)
 847                        dump_quoted_path("+++ ", "", "/dev/null",
 848                                         c_meta, c_reset);
 849                else
 850                        dump_quoted_path("+++ ", opt->b_prefix, elem->path,
 851                                         c_meta, c_reset);
 852                dump_sline(sline, cnt, num_parent,
 853                           DIFF_OPT_TST(opt, COLOR_DIFF));
 854        }
 855        free(result);
 856
 857        for (lno = 0; lno < cnt; lno++) {
 858                if (sline[lno].lost_head) {
 859                        struct lline *ll = sline[lno].lost_head;
 860                        while (ll) {
 861                                struct lline *tmp = ll;
 862                                ll = ll->next;
 863                                free(tmp);
 864                        }
 865                }
 866        }
 867        free(sline[0].p_lno);
 868        free(sline);
 869}
 870
 871#define COLONS "::::::::::::::::::::::::::::::::"
 872
 873static void show_raw_diff(struct combine_diff_path *p, int num_parent, struct rev_info *rev)
 874{
 875        struct diff_options *opt = &rev->diffopt;
 876        int i, offset;
 877        const char *prefix;
 878        int line_termination, inter_name_termination;
 879
 880        line_termination = opt->line_termination;
 881        inter_name_termination = '\t';
 882        if (!line_termination)
 883                inter_name_termination = 0;
 884
 885        if (rev->loginfo && !rev->no_commit_id)
 886                show_log(rev);
 887
 888        if (opt->output_format & DIFF_FORMAT_RAW) {
 889                offset = strlen(COLONS) - num_parent;
 890                if (offset < 0)
 891                        offset = 0;
 892                prefix = COLONS + offset;
 893
 894                /* Show the modes */
 895                for (i = 0; i < num_parent; i++) {
 896                        printf("%s%06o", prefix, p->parent[i].mode);
 897                        prefix = " ";
 898                }
 899                printf("%s%06o", prefix, p->mode);
 900
 901                /* Show sha1's */
 902                for (i = 0; i < num_parent; i++)
 903                        printf(" %s", diff_unique_abbrev(p->parent[i].sha1,
 904                                                         opt->abbrev));
 905                printf(" %s ", diff_unique_abbrev(p->sha1, opt->abbrev));
 906        }
 907
 908        if (opt->output_format & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS)) {
 909                for (i = 0; i < num_parent; i++)
 910                        putchar(p->parent[i].status);
 911                putchar(inter_name_termination);
 912        }
 913
 914        write_name_quoted(p->path, stdout, line_termination);
 915}
 916
 917void show_combined_diff(struct combine_diff_path *p,
 918                       int num_parent,
 919                       int dense,
 920                       struct rev_info *rev)
 921{
 922        struct diff_options *opt = &rev->diffopt;
 923        if (!p->len)
 924                return;
 925        if (opt->output_format & (DIFF_FORMAT_RAW |
 926                                  DIFF_FORMAT_NAME |
 927                                  DIFF_FORMAT_NAME_STATUS))
 928                show_raw_diff(p, num_parent, rev);
 929        else if (opt->output_format & DIFF_FORMAT_PATCH)
 930                show_patch_diff(p, num_parent, dense, rev);
 931}
 932
 933void diff_tree_combined(const unsigned char *sha1,
 934                        const unsigned char parent[][20],
 935                        int num_parent,
 936                        int dense,
 937                        struct rev_info *rev)
 938{
 939        struct diff_options *opt = &rev->diffopt;
 940        struct diff_options diffopts;
 941        struct combine_diff_path *p, *paths = NULL;
 942        int i, num_paths, needsep, show_log_first;
 943
 944        diffopts = *opt;
 945        diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
 946        DIFF_OPT_SET(&diffopts, RECURSIVE);
 947        DIFF_OPT_CLR(&diffopts, ALLOW_EXTERNAL);
 948
 949        show_log_first = !!rev->loginfo && !rev->no_commit_id;
 950        needsep = 0;
 951        /* find set of paths that everybody touches */
 952        for (i = 0; i < num_parent; i++) {
 953                /* show stat against the first parent even
 954                 * when doing combined diff.
 955                 */
 956                int stat_opt = (opt->output_format &
 957                                (DIFF_FORMAT_NUMSTAT|DIFF_FORMAT_DIFFSTAT));
 958                if (i == 0 && stat_opt)
 959                        diffopts.output_format = stat_opt;
 960                else
 961                        diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
 962                diff_tree_sha1(parent[i], sha1, "", &diffopts);
 963                diffcore_std(&diffopts);
 964                paths = intersect_paths(paths, i, num_parent);
 965
 966                if (show_log_first && i == 0) {
 967                        show_log(rev);
 968                        if (rev->verbose_header && opt->output_format)
 969                                putchar(opt->line_termination);
 970                }
 971                diff_flush(&diffopts);
 972        }
 973
 974        /* find out surviving paths */
 975        for (num_paths = 0, p = paths; p; p = p->next) {
 976                if (p->len)
 977                        num_paths++;
 978        }
 979        if (num_paths) {
 980                if (opt->output_format & (DIFF_FORMAT_RAW |
 981                                          DIFF_FORMAT_NAME |
 982                                          DIFF_FORMAT_NAME_STATUS)) {
 983                        for (p = paths; p; p = p->next) {
 984                                if (p->len)
 985                                        show_raw_diff(p, num_parent, rev);
 986                        }
 987                        needsep = 1;
 988                }
 989                else if (opt->output_format &
 990                         (DIFF_FORMAT_NUMSTAT|DIFF_FORMAT_DIFFSTAT))
 991                        needsep = 1;
 992                if (opt->output_format & DIFF_FORMAT_PATCH) {
 993                        if (needsep)
 994                                putchar(opt->line_termination);
 995                        for (p = paths; p; p = p->next) {
 996                                if (p->len)
 997                                        show_patch_diff(p, num_parent, dense,
 998                                                        rev);
 999                        }
1000                }
1001        }
1002
1003        /* Clean things up */
1004        while (paths) {
1005                struct combine_diff_path *tmp = paths;
1006                paths = paths->next;
1007                free(tmp);
1008        }
1009}
1010
1011void diff_tree_combined_merge(const unsigned char *sha1,
1012                             int dense, struct rev_info *rev)
1013{
1014        int num_parent;
1015        const unsigned char (*parent)[20];
1016        struct commit *commit = lookup_commit(sha1);
1017        struct commit_list *parents;
1018
1019        /* count parents */
1020        for (parents = commit->parents, num_parent = 0;
1021             parents;
1022             parents = parents->next, num_parent++)
1023                ; /* nothing */
1024
1025        parent = xmalloc(num_parent * sizeof(*parent));
1026        for (parents = commit->parents, num_parent = 0;
1027             parents;
1028             parents = parents->next, num_parent++)
1029                hashcpy((unsigned char*)(parent + num_parent),
1030                        parents->item->object.sha1);
1031        diff_tree_combined(sha1, parent, num_parent, dense, rev);
1032}