combine-diff.con commit simple euristic for further free packing improvements (4e8da19)
   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 int uninteresting(struct diff_filepair *p)
  11{
  12        if (diff_unmodified_pair(p))
  13                return 1;
  14        return 0;
  15}
  16
  17static struct combine_diff_path *intersect_paths(struct combine_diff_path *curr, int n, int num_parent)
  18{
  19        struct diff_queue_struct *q = &diff_queued_diff;
  20        struct combine_diff_path *p;
  21        int i;
  22
  23        if (!n) {
  24                struct combine_diff_path *list = NULL, **tail = &list;
  25                for (i = 0; i < q->nr; i++) {
  26                        int len;
  27                        const char *path;
  28                        if (uninteresting(q->queue[i]))
  29                                continue;
  30                        path = q->queue[i]->two->path;
  31                        len = strlen(path);
  32                        p = xmalloc(combine_diff_path_size(num_parent, len));
  33                        p->path = (char*) &(p->parent[num_parent]);
  34                        memcpy(p->path, path, len);
  35                        p->path[len] = 0;
  36                        p->len = len;
  37                        p->next = NULL;
  38                        memset(p->parent, 0,
  39                               sizeof(p->parent[0]) * num_parent);
  40
  41                        memcpy(p->sha1, q->queue[i]->two->sha1, 20);
  42                        p->mode = q->queue[i]->two->mode;
  43                        memcpy(p->parent[n].sha1, q->queue[i]->one->sha1, 20);
  44                        p->parent[n].mode = q->queue[i]->one->mode;
  45                        p->parent[n].status = q->queue[i]->status;
  46                        *tail = p;
  47                        tail = &p->next;
  48                }
  49                return list;
  50        }
  51
  52        for (p = curr; p; p = p->next) {
  53                int found = 0;
  54                if (!p->len)
  55                        continue;
  56                for (i = 0; i < q->nr; i++) {
  57                        const char *path;
  58                        int len;
  59
  60                        if (uninteresting(q->queue[i]))
  61                                continue;
  62                        path = q->queue[i]->two->path;
  63                        len = strlen(path);
  64                        if (len == p->len && !memcmp(path, p->path, len)) {
  65                                found = 1;
  66                                memcpy(p->parent[n].sha1,
  67                                       q->queue[i]->one->sha1, 20);
  68                                p->parent[n].mode = q->queue[i]->one->mode;
  69                                p->parent[n].status = q->queue[i]->status;
  70                                break;
  71                        }
  72                }
  73                if (!found)
  74                        p->len = 0;
  75        }
  76        return curr;
  77}
  78
  79/* Lines lost from parent */
  80struct lline {
  81        struct lline *next;
  82        int len;
  83        unsigned long parent_map;
  84        char line[FLEX_ARRAY];
  85};
  86
  87/* Lines surviving in the merge result */
  88struct sline {
  89        struct lline *lost_head, **lost_tail;
  90        char *bol;
  91        int len;
  92        /* bit 0 up to (N-1) are on if the parent has this line (i.e.
  93         * we did not change it).
  94         * bit N is used for "interesting" lines, including context.
  95         */
  96        unsigned long flag;
  97        unsigned long *p_lno;
  98};
  99
 100static char *grab_blob(const unsigned char *sha1, unsigned long *size)
 101{
 102        char *blob;
 103        char type[20];
 104        if (!memcmp(sha1, null_sha1, 20)) {
 105                /* deleted blob */
 106                *size = 0;
 107                return xcalloc(1, 1);
 108        }
 109        blob = read_sha1_file(sha1, type, size);
 110        if (strcmp(type, blob_type))
 111                die("object '%s' is not a blob!", sha1_to_hex(sha1));
 112        return blob;
 113}
 114
 115static void append_lost(struct sline *sline, int n, const char *line, int len)
 116{
 117        struct lline *lline;
 118        unsigned long this_mask = (1UL<<n);
 119        if (line[len-1] == '\n')
 120                len--;
 121
 122        /* Check to see if we can squash things */
 123        if (sline->lost_head) {
 124                struct lline *last_one = NULL;
 125                /* We cannot squash it with earlier one */
 126                for (lline = sline->lost_head;
 127                     lline;
 128                     lline = lline->next)
 129                        if (lline->parent_map & this_mask)
 130                                last_one = lline;
 131                lline = last_one ? last_one->next : sline->lost_head;
 132                while (lline) {
 133                        if (lline->len == len &&
 134                            !memcmp(lline->line, line, len)) {
 135                                lline->parent_map |= this_mask;
 136                                return;
 137                        }
 138                        lline = lline->next;
 139                }
 140        }
 141
 142        lline = xmalloc(sizeof(*lline) + len + 1);
 143        lline->len = len;
 144        lline->next = NULL;
 145        lline->parent_map = this_mask;
 146        memcpy(lline->line, line, len);
 147        lline->line[len] = 0;
 148        *sline->lost_tail = lline;
 149        sline->lost_tail = &lline->next;
 150}
 151
 152struct combine_diff_state {
 153        struct xdiff_emit_state xm;
 154
 155        unsigned int lno;
 156        int ob, on, nb, nn;
 157        unsigned long nmask;
 158        int num_parent;
 159        int n;
 160        struct sline *sline;
 161        struct sline *lost_bucket;
 162};
 163
 164static void consume_line(void *state_, char *line, unsigned long len)
 165{
 166        struct combine_diff_state *state = state_;
 167        if (5 < len && !memcmp("@@ -", line, 4)) {
 168                if (parse_hunk_header(line, len,
 169                                      &state->ob, &state->on,
 170                                      &state->nb, &state->nn))
 171                        return;
 172                state->lno = state->nb;
 173                if (!state->nb)
 174                        /* @@ -1,2 +0,0 @@ to remove the
 175                         * first two lines...
 176                         */
 177                        state->nb = 1;
 178                if (state->nn == 0)
 179                        /* @@ -X,Y +N,0 @@ removed Y lines
 180                         * that would have come *after* line N
 181                         * in the result.  Our lost buckets hang
 182                         * to the line after the removed lines,
 183                         */
 184                        state->lost_bucket = &state->sline[state->nb];
 185                else
 186                        state->lost_bucket = &state->sline[state->nb-1];
 187                if (!state->sline[state->nb-1].p_lno)
 188                        state->sline[state->nb-1].p_lno =
 189                                xcalloc(state->num_parent,
 190                                        sizeof(unsigned long));
 191                state->sline[state->nb-1].p_lno[state->n] = state->ob;
 192                return;
 193        }
 194        if (!state->lost_bucket)
 195                return; /* not in any hunk yet */
 196        switch (line[0]) {
 197        case '-':
 198                append_lost(state->lost_bucket, state->n, line+1, len-1);
 199                break;
 200        case '+':
 201                state->sline[state->lno-1].flag |= state->nmask;
 202                state->lno++;
 203                break;
 204        }
 205}
 206
 207static void combine_diff(const unsigned char *parent, mmfile_t *result_file,
 208                         struct sline *sline, int cnt, int n, int num_parent)
 209{
 210        unsigned int p_lno, lno;
 211        unsigned long nmask = (1UL << n);
 212        xpparam_t xpp;
 213        xdemitconf_t xecfg;
 214        mmfile_t parent_file;
 215        xdemitcb_t ecb;
 216        struct combine_diff_state state;
 217        unsigned long sz;
 218
 219        if (!cnt)
 220                return; /* result deleted */
 221
 222        parent_file.ptr = grab_blob(parent, &sz);
 223        parent_file.size = sz;
 224        xpp.flags = XDF_NEED_MINIMAL;
 225        xecfg.ctxlen = 0;
 226        xecfg.flags = 0;
 227        ecb.outf = xdiff_outf;
 228        ecb.priv = &state;
 229        memset(&state, 0, sizeof(state));
 230        state.xm.consume = consume_line;
 231        state.nmask = nmask;
 232        state.sline = sline;
 233        state.lno = 1;
 234        state.num_parent = num_parent;
 235        state.n = n;
 236
 237        xdl_diff(&parent_file, result_file, &xpp, &xecfg, &ecb);
 238        free(parent_file.ptr);
 239
 240        /* Assign line numbers for this parent.
 241         *
 242         * sline[lno].p_lno[n] records the first line number
 243         * (counting from 1) for parent N if the final hunk display
 244         * started by showing sline[lno] (possibly showing the lost
 245         * lines attached to it first).
 246         */
 247        for (lno = 0,  p_lno = 1; lno <= cnt; lno++) {
 248                struct lline *ll;
 249                sline[lno].p_lno[n] = p_lno;
 250
 251                /* How many lines would this sline advance the p_lno? */
 252                ll = sline[lno].lost_head;
 253                while (ll) {
 254                        if (ll->parent_map & nmask)
 255                                p_lno++; /* '-' means parent had it */
 256                        ll = ll->next;
 257                }
 258                if (lno < cnt && !(sline[lno].flag & nmask))
 259                        p_lno++; /* no '+' means parent had it */
 260        }
 261        sline[lno].p_lno[n] = p_lno; /* trailer */
 262}
 263
 264static unsigned long context = 3;
 265static char combine_marker = '@';
 266
 267static int interesting(struct sline *sline, unsigned long all_mask)
 268{
 269        /* If some parents lost lines here, or if we have added to
 270         * some parent, it is interesting.
 271         */
 272        return ((sline->flag & all_mask) || sline->lost_head);
 273}
 274
 275static unsigned long adjust_hunk_tail(struct sline *sline,
 276                                      unsigned long all_mask,
 277                                      unsigned long hunk_begin,
 278                                      unsigned long i)
 279{
 280        /* i points at the first uninteresting line.  If the last line
 281         * of the hunk was interesting only because it has some
 282         * deletion, then it is not all that interesting for the
 283         * purpose of giving trailing context lines.  This is because
 284         * we output '-' line and then unmodified sline[i-1] itself in
 285         * that case which gives us one extra context line.
 286         */
 287        if ((hunk_begin + 1 <= i) && !(sline[i-1].flag & all_mask))
 288                i--;
 289        return i;
 290}
 291
 292static unsigned long find_next(struct sline *sline,
 293                               unsigned long mark,
 294                               unsigned long i,
 295                               unsigned long cnt,
 296                               int uninteresting)
 297{
 298        /* We have examined up to i-1 and are about to look at i.
 299         * Find next interesting or uninteresting line.  Here,
 300         * "interesting" does not mean interesting(), but marked by
 301         * the give_context() function below (i.e. it includes context
 302         * lines that are not interesting to interesting() function
 303         * that are surrounded by interesting() ones.
 304         */
 305        while (i <= cnt)
 306                if (uninteresting
 307                    ? !(sline[i].flag & mark)
 308                    : (sline[i].flag & mark))
 309                        return i;
 310                else
 311                        i++;
 312        return i;
 313}
 314
 315static int give_context(struct sline *sline, unsigned long cnt, int num_parent)
 316{
 317        unsigned long all_mask = (1UL<<num_parent) - 1;
 318        unsigned long mark = (1UL<<num_parent);
 319        unsigned long i;
 320
 321        /* Two groups of interesting lines may have a short gap of
 322         * unintersting lines.  Connect such groups to give them a
 323         * bit of context.
 324         *
 325         * We first start from what the interesting() function says,
 326         * and mark them with "mark", and paint context lines with the
 327         * mark.  So interesting() would still say false for such context
 328         * lines but they are treated as "interesting" in the end.
 329         */
 330        i = find_next(sline, mark, 0, cnt, 0);
 331        if (cnt < i)
 332                return 0;
 333
 334        while (i <= cnt) {
 335                unsigned long j = (context < i) ? (i - context) : 0;
 336                unsigned long k;
 337
 338                /* Paint a few lines before the first interesting line. */
 339                while (j < i)
 340                        sline[j++].flag |= mark;
 341
 342        again:
 343                /* we know up to i is to be included.  where does the
 344                 * next uninteresting one start?
 345                 */
 346                j = find_next(sline, mark, i, cnt, 1);
 347                if (cnt < j)
 348                        break; /* the rest are all interesting */
 349
 350                /* lookahead context lines */
 351                k = find_next(sline, mark, j, cnt, 0);
 352                j = adjust_hunk_tail(sline, all_mask, i, j);
 353
 354                if (k < j + context) {
 355                        /* k is interesting and [j,k) are not, but
 356                         * paint them interesting because the gap is small.
 357                         */
 358                        while (j < k)
 359                                sline[j++].flag |= mark;
 360                        i = k;
 361                        goto again;
 362                }
 363
 364                /* j is the first uninteresting line and there is
 365                 * no overlap beyond it within context lines.  Paint
 366                 * the trailing edge a bit.
 367                 */
 368                i = k;
 369                k = (j + context < cnt+1) ? j + context : cnt+1;
 370                while (j < k)
 371                        sline[j++].flag |= mark;
 372        }
 373        return 1;
 374}
 375
 376static int make_hunks(struct sline *sline, unsigned long cnt,
 377                       int num_parent, int dense)
 378{
 379        unsigned long all_mask = (1UL<<num_parent) - 1;
 380        unsigned long mark = (1UL<<num_parent);
 381        unsigned long i;
 382        int has_interesting = 0;
 383
 384        for (i = 0; i <= cnt; i++) {
 385                if (interesting(&sline[i], all_mask))
 386                        sline[i].flag |= mark;
 387                else
 388                        sline[i].flag &= ~mark;
 389        }
 390        if (!dense)
 391                return give_context(sline, cnt, num_parent);
 392
 393        /* Look at each hunk, and if we have changes from only one
 394         * parent, or the changes are the same from all but one
 395         * parent, mark that uninteresting.
 396         */
 397        i = 0;
 398        while (i <= cnt) {
 399                unsigned long j, hunk_begin, hunk_end;
 400                unsigned long same_diff;
 401                while (i <= cnt && !(sline[i].flag & mark))
 402                        i++;
 403                if (cnt < i)
 404                        break; /* No more interesting hunks */
 405                hunk_begin = i;
 406                for (j = i + 1; j <= cnt; j++) {
 407                        if (!(sline[j].flag & mark)) {
 408                                /* Look beyond the end to see if there
 409                                 * is an interesting line after this
 410                                 * hunk within context span.
 411                                 */
 412                                unsigned long la; /* lookahead */
 413                                int contin = 0;
 414                                la = adjust_hunk_tail(sline, all_mask,
 415                                                     hunk_begin, j);
 416                                la = (la + context < cnt + 1) ?
 417                                        (la + context) : cnt + 1;
 418                                while (j <= --la) {
 419                                        if (sline[la].flag & mark) {
 420                                                contin = 1;
 421                                                break;
 422                                        }
 423                                }
 424                                if (!contin)
 425                                        break;
 426                                j = la;
 427                        }
 428                }
 429                hunk_end = j;
 430
 431                /* [i..hunk_end) are interesting.  Now is it really
 432                 * interesting?  We check if there are only two versions
 433                 * and the result matches one of them.  That is, we look
 434                 * at:
 435                 *   (+) line, which records lines added to which parents;
 436                 *       this line appears in the result.
 437                 *   (-) line, which records from what parents the line
 438                 *       was removed; this line does not appear in the result.
 439                 * then check the set of parents the result has difference
 440                 * from, from all lines.  If there are lines that has
 441                 * different set of parents that the result has differences
 442                 * from, that means we have more than two versions.
 443                 *
 444                 * Even when we have only two versions, if the result does
 445                 * not match any of the parents, the it should be considered
 446                 * interesting.  In such a case, we would have all '+' line.
 447                 * After passing the above "two versions" test, that would
 448                 * appear as "the same set of parents" to be "all parents".
 449                 */
 450                same_diff = 0;
 451                has_interesting = 0;
 452                for (j = i; j < hunk_end && !has_interesting; j++) {
 453                        unsigned long this_diff = sline[j].flag & all_mask;
 454                        struct lline *ll = sline[j].lost_head;
 455                        if (this_diff) {
 456                                /* This has some changes.  Is it the
 457                                 * same as others?
 458                                 */
 459                                if (!same_diff)
 460                                        same_diff = this_diff;
 461                                else if (same_diff != this_diff) {
 462                                        has_interesting = 1;
 463                                        break;
 464                                }
 465                        }
 466                        while (ll && !has_interesting) {
 467                                /* Lost this line from these parents;
 468                                 * who are they?  Are they the same?
 469                                 */
 470                                this_diff = ll->parent_map;
 471                                if (!same_diff)
 472                                        same_diff = this_diff;
 473                                else if (same_diff != this_diff) {
 474                                        has_interesting = 1;
 475                                }
 476                                ll = ll->next;
 477                        }
 478                }
 479
 480                if (!has_interesting && same_diff != all_mask) {
 481                        /* This hunk is not that interesting after all */
 482                        for (j = hunk_begin; j < hunk_end; j++)
 483                                sline[j].flag &= ~mark;
 484                }
 485                i = hunk_end;
 486        }
 487
 488        has_interesting = give_context(sline, cnt, num_parent);
 489        return has_interesting;
 490}
 491
 492static void show_parent_lno(struct sline *sline, unsigned long l0, unsigned long l1, unsigned long cnt, int n)
 493{
 494        l0 = sline[l0].p_lno[n];
 495        l1 = sline[l1].p_lno[n];
 496        printf(" -%lu,%lu", l0, l1-l0);
 497}
 498
 499static void dump_sline(struct sline *sline, unsigned long cnt, int num_parent)
 500{
 501        unsigned long mark = (1UL<<num_parent);
 502        int i;
 503        unsigned long lno = 0;
 504
 505        if (!cnt)
 506                return; /* result deleted */
 507
 508        while (1) {
 509                struct sline *sl = &sline[lno];
 510                unsigned long hunk_end;
 511                unsigned long rlines;
 512                while (lno <= cnt && !(sline[lno].flag & mark))
 513                        lno++;
 514                if (cnt < lno)
 515                        break;
 516                else {
 517                        for (hunk_end = lno + 1; hunk_end <= cnt; hunk_end++)
 518                                if (!(sline[hunk_end].flag & mark))
 519                                        break;
 520                }
 521                rlines = hunk_end - lno;
 522                if (cnt < hunk_end)
 523                        rlines--; /* pointing at the last delete hunk */
 524                for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 525                for (i = 0; i < num_parent; i++)
 526                        show_parent_lno(sline, lno, hunk_end, cnt, i);
 527                printf(" +%lu,%lu ", lno+1, rlines);
 528                for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 529                putchar('\n');
 530                while (lno < hunk_end) {
 531                        struct lline *ll;
 532                        int j;
 533                        unsigned long p_mask;
 534                        sl = &sline[lno++];
 535                        ll = sl->lost_head;
 536                        while (ll) {
 537                                for (j = 0; j < num_parent; j++) {
 538                                        if (ll->parent_map & (1UL<<j))
 539                                                putchar('-');
 540                                        else
 541                                                putchar(' ');
 542                                }
 543                                puts(ll->line);
 544                                ll = ll->next;
 545                        }
 546                        if (cnt < lno)
 547                                break;
 548                        p_mask = 1;
 549                        for (j = 0; j < num_parent; j++) {
 550                                if (p_mask & sl->flag)
 551                                        putchar('+');
 552                                else
 553                                        putchar(' ');
 554                                p_mask <<= 1;
 555                        }
 556                        printf("%.*s\n", sl->len, sl->bol);
 557                }
 558        }
 559}
 560
 561static void reuse_combine_diff(struct sline *sline, unsigned long cnt,
 562                               int i, int j)
 563{
 564        /* We have already examined parent j and we know parent i
 565         * and parent j are the same, so reuse the combined result
 566         * of parent j for parent i.
 567         */
 568        unsigned long lno, imask, jmask;
 569        imask = (1UL<<i);
 570        jmask = (1UL<<j);
 571
 572        for (lno = 0; lno <= cnt; lno++) {
 573                struct lline *ll = sline->lost_head;
 574                sline->p_lno[i] = sline->p_lno[j];
 575                while (ll) {
 576                        if (ll->parent_map & jmask)
 577                                ll->parent_map |= imask;
 578                        ll = ll->next;
 579                }
 580                if (sline->flag & jmask)
 581                        sline->flag |= imask;
 582                sline++;
 583        }
 584        /* the overall size of the file (sline[cnt]) */
 585        sline->p_lno[i] = sline->p_lno[j];
 586}
 587
 588static void dump_quoted_path(const char *prefix, const char *path)
 589{
 590        fputs(prefix, stdout);
 591        if (quote_c_style(path, NULL, NULL, 0))
 592                quote_c_style(path, NULL, stdout, 0);
 593        else
 594                printf("%s", path);
 595        putchar('\n');
 596}
 597
 598static int show_patch_diff(struct combine_diff_path *elem, int num_parent,
 599                           int dense, struct rev_info *rev)
 600{
 601        struct diff_options *opt = &rev->diffopt;
 602        unsigned long result_size, cnt, lno;
 603        char *result, *cp;
 604        struct sline *sline; /* survived lines */
 605        int mode_differs = 0;
 606        int i, show_hunks, shown_header = 0;
 607        int working_tree_file = !memcmp(elem->sha1, null_sha1, 20);
 608        int abbrev = opt->full_index ? 40 : DEFAULT_ABBREV;
 609        mmfile_t result_file;
 610
 611        /* Read the result of merge first */
 612        if (!working_tree_file)
 613                result = grab_blob(elem->sha1, &result_size);
 614        else {
 615                /* Used by diff-tree to read from the working tree */
 616                struct stat st;
 617                int fd;
 618                if (0 <= (fd = open(elem->path, O_RDONLY)) &&
 619                    !fstat(fd, &st)) {
 620                        int len = st.st_size;
 621                        int cnt = 0;
 622
 623                        elem->mode = canon_mode(st.st_mode);
 624                        result_size = len;
 625                        result = xmalloc(len + 1);
 626                        while (cnt < len) {
 627                                int done = xread(fd, result+cnt, len-cnt);
 628                                if (done == 0)
 629                                        break;
 630                                if (done < 0)
 631                                        die("read error '%s'", elem->path);
 632                                cnt += done;
 633                        }
 634                        result[len] = 0;
 635                }
 636                else {
 637                        /* deleted file */
 638                        result_size = 0;
 639                        elem->mode = 0;
 640                        result = xmalloc(1);
 641                        result[0] = 0;
 642                }
 643                if (0 <= fd)
 644                        close(fd);
 645        }
 646
 647        for (cnt = 0, cp = result; cp - result < result_size; cp++) {
 648                if (*cp == '\n')
 649                        cnt++;
 650        }
 651        if (result_size && result[result_size-1] != '\n')
 652                cnt++; /* incomplete line */
 653
 654        sline = xcalloc(cnt+2, sizeof(*sline));
 655        sline[0].bol = result;
 656        for (lno = 0; lno <= cnt + 1; lno++) {
 657                sline[lno].lost_tail = &sline[lno].lost_head;
 658                sline[lno].flag = 0;
 659        }
 660        for (lno = 0, cp = result; cp - result < result_size; cp++) {
 661                if (*cp == '\n') {
 662                        sline[lno].len = cp - sline[lno].bol;
 663                        lno++;
 664                        if (lno < cnt)
 665                                sline[lno].bol = cp + 1;
 666                }
 667        }
 668        if (result_size && result[result_size-1] != '\n')
 669                sline[cnt-1].len = result_size - (sline[cnt-1].bol - result);
 670
 671        result_file.ptr = result;
 672        result_file.size = result_size;
 673
 674        /* Even p_lno[cnt+1] is valid -- that is for the end line number
 675         * for deletion hunk at the end.
 676         */
 677        sline[0].p_lno = xcalloc((cnt+2) * num_parent, sizeof(unsigned long));
 678        for (lno = 0; lno <= cnt; lno++)
 679                sline[lno+1].p_lno = sline[lno].p_lno + num_parent;
 680
 681        for (i = 0; i < num_parent; i++) {
 682                int j;
 683                for (j = 0; j < i; j++) {
 684                        if (!memcmp(elem->parent[i].sha1,
 685                                    elem->parent[j].sha1, 20)) {
 686                                reuse_combine_diff(sline, cnt, i, j);
 687                                break;
 688                        }
 689                }
 690                if (i <= j)
 691                        combine_diff(elem->parent[i].sha1, &result_file, sline,
 692                                     cnt, i, num_parent);
 693                if (elem->parent[i].mode != elem->mode)
 694                        mode_differs = 1;
 695        }
 696
 697        show_hunks = make_hunks(sline, cnt, num_parent, dense);
 698
 699        if (show_hunks || mode_differs || working_tree_file) {
 700                const char *abb;
 701
 702                if (rev->loginfo)
 703                        show_log(rev, rev->loginfo, "\n");
 704                dump_quoted_path(dense ? "diff --cc " : "diff --combined ", elem->path);
 705                printf("index ");
 706                for (i = 0; i < num_parent; i++) {
 707                        abb = find_unique_abbrev(elem->parent[i].sha1,
 708                                                 abbrev);
 709                        printf("%s%s", i ? "," : "", abb);
 710                }
 711                abb = find_unique_abbrev(elem->sha1, abbrev);
 712                printf("..%s\n", abb);
 713
 714                if (mode_differs) {
 715                        int added = !!elem->mode;
 716                        for (i = 0; added && i < num_parent; i++)
 717                                if (elem->parent[i].status !=
 718                                    DIFF_STATUS_ADDED)
 719                                        added = 0;
 720                        if (added)
 721                                printf("new file mode %06o", elem->mode);
 722                        else {
 723                                if (!elem->mode)
 724                                        printf("deleted file ");
 725                                printf("mode ");
 726                                for (i = 0; i < num_parent; i++) {
 727                                        printf("%s%06o", i ? "," : "",
 728                                               elem->parent[i].mode);
 729                                }
 730                                if (elem->mode)
 731                                        printf("..%06o", elem->mode);
 732                        }
 733                        putchar('\n');
 734                }
 735                dump_quoted_path("--- a/", elem->path);
 736                dump_quoted_path("+++ b/", elem->path);
 737                dump_sline(sline, cnt, num_parent);
 738        }
 739        free(result);
 740
 741        for (i = 0; i < cnt; i++) {
 742                if (sline[i].lost_head) {
 743                        struct lline *ll = sline[i].lost_head;
 744                        while (ll) {
 745                                struct lline *tmp = ll;
 746                                ll = ll->next;
 747                                free(tmp);
 748                        }
 749                }
 750        }
 751        free(sline[0].p_lno);
 752        free(sline);
 753        return shown_header;
 754}
 755
 756#define COLONS "::::::::::::::::::::::::::::::::"
 757
 758static void show_raw_diff(struct combine_diff_path *p, int num_parent, struct rev_info *rev)
 759{
 760        struct diff_options *opt = &rev->diffopt;
 761        int i, offset;
 762        const char *prefix;
 763        int line_termination, inter_name_termination;
 764
 765        line_termination = opt->line_termination;
 766        inter_name_termination = '\t';
 767        if (!line_termination)
 768                inter_name_termination = 0;
 769
 770        if (rev->loginfo)
 771                show_log(rev, rev->loginfo, "\n");
 772
 773        if (opt->output_format == DIFF_FORMAT_RAW) {
 774                offset = strlen(COLONS) - num_parent;
 775                if (offset < 0)
 776                        offset = 0;
 777                prefix = COLONS + offset;
 778
 779                /* Show the modes */
 780                for (i = 0; i < num_parent; i++) {
 781                        printf("%s%06o", prefix, p->parent[i].mode);
 782                        prefix = " ";
 783                }
 784                printf("%s%06o", prefix, p->mode);
 785
 786                /* Show sha1's */
 787                for (i = 0; i < num_parent; i++)
 788                        printf(" %s", diff_unique_abbrev(p->parent[i].sha1,
 789                                                         opt->abbrev));
 790                printf(" %s ", diff_unique_abbrev(p->sha1, opt->abbrev));
 791        }
 792
 793        if (opt->output_format == DIFF_FORMAT_RAW ||
 794            opt->output_format == DIFF_FORMAT_NAME_STATUS) {
 795                for (i = 0; i < num_parent; i++)
 796                        putchar(p->parent[i].status);
 797                putchar(inter_name_termination);
 798        }
 799
 800        if (line_termination) {
 801                if (quote_c_style(p->path, NULL, NULL, 0))
 802                        quote_c_style(p->path, NULL, stdout, 0);
 803                else
 804                        printf("%s", p->path);
 805                putchar(line_termination);
 806        }
 807        else {
 808                printf("%s%c", p->path, line_termination);
 809        }
 810}
 811
 812void show_combined_diff(struct combine_diff_path *p,
 813                       int num_parent,
 814                       int dense,
 815                       struct rev_info *rev)
 816{
 817        struct diff_options *opt = &rev->diffopt;
 818        if (!p->len)
 819                return;
 820        switch (opt->output_format) {
 821        case DIFF_FORMAT_RAW:
 822        case DIFF_FORMAT_NAME_STATUS:
 823        case DIFF_FORMAT_NAME:
 824                show_raw_diff(p, num_parent, rev);
 825                return;
 826        case DIFF_FORMAT_PATCH:
 827                show_patch_diff(p, num_parent, dense, rev);
 828                return;
 829        default:
 830                return;
 831        }
 832}
 833
 834void diff_tree_combined(const unsigned char *sha1,
 835                        const unsigned char parent[][20],
 836                        int num_parent,
 837                        int dense,
 838                        struct rev_info *rev)
 839{
 840        struct diff_options *opt = &rev->diffopt;
 841        struct diff_options diffopts;
 842        struct combine_diff_path *p, *paths = NULL;
 843        int i, num_paths;
 844        int do_diffstat;
 845
 846        do_diffstat = (opt->output_format == DIFF_FORMAT_DIFFSTAT ||
 847                       opt->with_stat);
 848        diffopts = *opt;
 849        diffopts.with_raw = 0;
 850        diffopts.with_stat = 0;
 851        diffopts.recursive = 1;
 852
 853        /* find set of paths that everybody touches */
 854        for (i = 0; i < num_parent; i++) {
 855                /* show stat against the first parent even
 856                 * when doing combined diff.
 857                 */
 858                if (i == 0 && do_diffstat)
 859                        diffopts.output_format = DIFF_FORMAT_DIFFSTAT;
 860                else
 861                        diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
 862                diff_tree_sha1(parent[i], sha1, "", &diffopts);
 863                diffcore_std(&diffopts);
 864                paths = intersect_paths(paths, i, num_parent);
 865
 866                if (do_diffstat && rev->loginfo)
 867                        show_log(rev, rev->loginfo,
 868                                 opt->with_stat ? "---\n" : "\n");
 869                diff_flush(&diffopts);
 870                if (opt->with_stat)
 871                        putchar('\n');
 872        }
 873
 874        /* find out surviving paths */
 875        for (num_paths = 0, p = paths; p; p = p->next) {
 876                if (p->len)
 877                        num_paths++;
 878        }
 879        if (num_paths) {
 880                if (opt->with_raw) {
 881                        int saved_format = opt->output_format;
 882                        opt->output_format = DIFF_FORMAT_RAW;
 883                        for (p = paths; p; p = p->next) {
 884                                show_combined_diff(p, num_parent, dense, rev);
 885                        }
 886                        opt->output_format = saved_format;
 887                        putchar(opt->line_termination);
 888                }
 889                for (p = paths; p; p = p->next) {
 890                        show_combined_diff(p, num_parent, dense, rev);
 891                }
 892        }
 893
 894        /* Clean things up */
 895        while (paths) {
 896                struct combine_diff_path *tmp = paths;
 897                paths = paths->next;
 898                free(tmp);
 899        }
 900}
 901
 902void diff_tree_combined_merge(const unsigned char *sha1,
 903                             int dense, struct rev_info *rev)
 904{
 905        int num_parent;
 906        const unsigned char (*parent)[20];
 907        struct commit *commit = lookup_commit(sha1);
 908        struct commit_list *parents;
 909
 910        /* count parents */
 911        for (parents = commit->parents, num_parent = 0;
 912             parents;
 913             parents = parents->next, num_parent++)
 914                ; /* nothing */
 915
 916        parent = xmalloc(num_parent * sizeof(*parent));
 917        for (parents = commit->parents, num_parent = 0;
 918             parents;
 919             parents = parents->next, num_parent++)
 920                memcpy(parent + num_parent, parents->item->object.sha1, 20);
 921        diff_tree_combined(sha1, parent, num_parent, dense, rev);
 922}