combine-diff.con commit Merge branch 'ak/bisect-reset-to-switch' (4b3c180)
   1#include "cache.h"
   2#include "commit.h"
   3#include "blob.h"
   4#include "diff.h"
   5#include "diffcore.h"
   6#include "quote.h"
   7#include "xdiff-interface.h"
   8#include "log-tree.h"
   9#include "refs.h"
  10
  11static struct combine_diff_path *intersect_paths(struct combine_diff_path *curr, int n, int num_parent)
  12{
  13        struct diff_queue_struct *q = &diff_queued_diff;
  14        struct combine_diff_path *p;
  15        int i;
  16
  17        if (!n) {
  18                struct combine_diff_path *list = NULL, **tail = &list;
  19                for (i = 0; i < q->nr; i++) {
  20                        int len;
  21                        const char *path;
  22                        if (diff_unmodified_pair(q->queue[i]))
  23                                continue;
  24                        path = q->queue[i]->two->path;
  25                        len = strlen(path);
  26                        p = xmalloc(combine_diff_path_size(num_parent, len));
  27                        p->path = (char *) &(p->parent[num_parent]);
  28                        memcpy(p->path, path, len);
  29                        p->path[len] = 0;
  30                        p->len = len;
  31                        p->next = NULL;
  32                        memset(p->parent, 0,
  33                               sizeof(p->parent[0]) * num_parent);
  34
  35                        hashcpy(p->sha1, q->queue[i]->two->sha1);
  36                        p->mode = q->queue[i]->two->mode;
  37                        hashcpy(p->parent[n].sha1, q->queue[i]->one->sha1);
  38                        p->parent[n].mode = q->queue[i]->one->mode;
  39                        p->parent[n].status = q->queue[i]->status;
  40                        *tail = p;
  41                        tail = &p->next;
  42                }
  43                return list;
  44        }
  45
  46        for (p = curr; p; p = p->next) {
  47                int found = 0;
  48                if (!p->len)
  49                        continue;
  50                for (i = 0; i < q->nr; i++) {
  51                        const char *path;
  52                        int len;
  53
  54                        if (diff_unmodified_pair(q->queue[i]))
  55                                continue;
  56                        path = q->queue[i]->two->path;
  57                        len = strlen(path);
  58                        if (len == p->len && !memcmp(path, p->path, len)) {
  59                                found = 1;
  60                                hashcpy(p->parent[n].sha1, q->queue[i]->one->sha1);
  61                                p->parent[n].mode = q->queue[i]->one->mode;
  62                                p->parent[n].status = q->queue[i]->status;
  63                                break;
  64                        }
  65                }
  66                if (!found)
  67                        p->len = 0;
  68        }
  69        return curr;
  70}
  71
  72/* Lines lost from parent */
  73struct lline {
  74        struct lline *next;
  75        int len;
  76        unsigned long parent_map;
  77        char line[FLEX_ARRAY];
  78};
  79
  80/* Lines surviving in the merge result */
  81struct sline {
  82        struct lline *lost_head, **lost_tail;
  83        struct lline *next_lost;
  84        char *bol;
  85        int len;
  86        /* bit 0 up to (N-1) are on if the parent has this line (i.e.
  87         * we did not change it).
  88         * bit N is used for "interesting" lines, including context.
  89         * bit (N+1) is used for "do not show deletion before this".
  90         */
  91        unsigned long flag;
  92        unsigned long *p_lno;
  93};
  94
  95static char *grab_blob(const unsigned char *sha1, unsigned int mode, unsigned long *size)
  96{
  97        char *blob;
  98        enum object_type type;
  99
 100        if (S_ISGITLINK(mode)) {
 101                blob = xmalloc(100);
 102                *size = snprintf(blob, 100,
 103                                 "Subproject commit %s\n", sha1_to_hex(sha1));
 104        } else if (is_null_sha1(sha1)) {
 105                /* deleted blob */
 106                *size = 0;
 107                return xcalloc(1, 1);
 108        } else {
 109                blob = read_sha1_file(sha1, &type, size);
 110                if (type != OBJ_BLOB)
 111                        die("object '%s' is not a blob!", sha1_to_hex(sha1));
 112        }
 113        return blob;
 114}
 115
 116static void append_lost(struct sline *sline, int n, const char *line, int len)
 117{
 118        struct lline *lline;
 119        unsigned long this_mask = (1UL<<n);
 120        if (line[len-1] == '\n')
 121                len--;
 122
 123        /* Check to see if we can squash things */
 124        if (sline->lost_head) {
 125                lline = sline->next_lost;
 126                while (lline) {
 127                        if (lline->len == len &&
 128                            !memcmp(lline->line, line, len)) {
 129                                lline->parent_map |= this_mask;
 130                                sline->next_lost = lline->next;
 131                                return;
 132                        }
 133                        lline = lline->next;
 134                }
 135        }
 136
 137        lline = xmalloc(sizeof(*lline) + len + 1);
 138        lline->len = len;
 139        lline->next = NULL;
 140        lline->parent_map = this_mask;
 141        memcpy(lline->line, line, len);
 142        lline->line[len] = 0;
 143        *sline->lost_tail = lline;
 144        sline->lost_tail = &lline->next;
 145        sline->next_lost = NULL;
 146}
 147
 148struct combine_diff_state {
 149        unsigned int lno;
 150        int ob, on, nb, nn;
 151        unsigned long nmask;
 152        int num_parent;
 153        int n;
 154        struct sline *sline;
 155        struct sline *lost_bucket;
 156};
 157
 158static void consume_line(void *state_, char *line, unsigned long len)
 159{
 160        struct combine_diff_state *state = state_;
 161        if (5 < len && !memcmp("@@ -", line, 4)) {
 162                if (parse_hunk_header(line, len,
 163                                      &state->ob, &state->on,
 164                                      &state->nb, &state->nn))
 165                        return;
 166                state->lno = state->nb;
 167                if (state->nn == 0) {
 168                        /* @@ -X,Y +N,0 @@ removed Y lines
 169                         * that would have come *after* line N
 170                         * in the result.  Our lost buckets hang
 171                         * to the line after the removed lines,
 172                         *
 173                         * Note that this is correct even when N == 0,
 174                         * in which case the hunk removes the first
 175                         * line in the file.
 176                         */
 177                        state->lost_bucket = &state->sline[state->nb];
 178                        if (!state->nb)
 179                                state->nb = 1;
 180                } else {
 181                        state->lost_bucket = &state->sline[state->nb-1];
 182                }
 183                if (!state->sline[state->nb-1].p_lno)
 184                        state->sline[state->nb-1].p_lno =
 185                                xcalloc(state->num_parent,
 186                                        sizeof(unsigned long));
 187                state->sline[state->nb-1].p_lno[state->n] = state->ob;
 188                state->lost_bucket->next_lost = state->lost_bucket->lost_head;
 189                return;
 190        }
 191        if (!state->lost_bucket)
 192                return; /* not in any hunk yet */
 193        switch (line[0]) {
 194        case '-':
 195                append_lost(state->lost_bucket, state->n, line+1, len-1);
 196                break;
 197        case '+':
 198                state->sline[state->lno-1].flag |= state->nmask;
 199                state->lno++;
 200                break;
 201        }
 202}
 203
 204static void combine_diff(const unsigned char *parent, unsigned int mode,
 205                         mmfile_t *result_file,
 206                         struct sline *sline, unsigned int cnt, int n,
 207                         int num_parent)
 208{
 209        unsigned int p_lno, lno;
 210        unsigned long nmask = (1UL << n);
 211        xpparam_t xpp;
 212        xdemitconf_t xecfg;
 213        mmfile_t parent_file;
 214        xdemitcb_t ecb;
 215        struct combine_diff_state state;
 216        unsigned long sz;
 217
 218        if (!cnt)
 219                return; /* result deleted */
 220
 221        parent_file.ptr = grab_blob(parent, mode, &sz);
 222        parent_file.size = sz;
 223        memset(&xpp, 0, sizeof(xpp));
 224        xpp.flags = XDF_NEED_MINIMAL;
 225        memset(&xecfg, 0, sizeof(xecfg));
 226        memset(&state, 0, sizeof(state));
 227        state.nmask = nmask;
 228        state.sline = sline;
 229        state.lno = 1;
 230        state.num_parent = num_parent;
 231        state.n = n;
 232
 233        xdi_diff_outf(&parent_file, result_file, consume_line, &state,
 234                      &xpp, &xecfg, &ecb);
 235        free(parent_file.ptr);
 236
 237        /* Assign line numbers for this parent.
 238         *
 239         * sline[lno].p_lno[n] records the first line number
 240         * (counting from 1) for parent N if the final hunk display
 241         * started by showing sline[lno] (possibly showing the lost
 242         * lines attached to it first).
 243         */
 244        for (lno = 0,  p_lno = 1; lno <= cnt; lno++) {
 245                struct lline *ll;
 246                sline[lno].p_lno[n] = p_lno;
 247
 248                /* How many lines would this sline advance the p_lno? */
 249                ll = sline[lno].lost_head;
 250                while (ll) {
 251                        if (ll->parent_map & nmask)
 252                                p_lno++; /* '-' means parent had it */
 253                        ll = ll->next;
 254                }
 255                if (lno < cnt && !(sline[lno].flag & nmask))
 256                        p_lno++; /* no '+' means parent had it */
 257        }
 258        sline[lno].p_lno[n] = p_lno; /* trailer */
 259}
 260
 261static unsigned long context = 3;
 262static char combine_marker = '@';
 263
 264static int interesting(struct sline *sline, unsigned long all_mask)
 265{
 266        /* If some parents lost lines here, or if we have added to
 267         * some parent, it is interesting.
 268         */
 269        return ((sline->flag & all_mask) || sline->lost_head);
 270}
 271
 272static unsigned long adjust_hunk_tail(struct sline *sline,
 273                                      unsigned long all_mask,
 274                                      unsigned long hunk_begin,
 275                                      unsigned long i)
 276{
 277        /* i points at the first uninteresting line.  If the last line
 278         * of the hunk was interesting only because it has some
 279         * deletion, then it is not all that interesting for the
 280         * purpose of giving trailing context lines.  This is because
 281         * we output '-' line and then unmodified sline[i-1] itself in
 282         * that case which gives us one extra context line.
 283         */
 284        if ((hunk_begin + 1 <= i) && !(sline[i-1].flag & all_mask))
 285                i--;
 286        return i;
 287}
 288
 289static unsigned long find_next(struct sline *sline,
 290                               unsigned long mark,
 291                               unsigned long i,
 292                               unsigned long cnt,
 293                               int look_for_uninteresting)
 294{
 295        /* We have examined up to i-1 and are about to look at i.
 296         * Find next interesting or uninteresting line.  Here,
 297         * "interesting" does not mean interesting(), but marked by
 298         * the give_context() function below (i.e. it includes context
 299         * lines that are not interesting to interesting() function
 300         * that are surrounded by interesting() ones.
 301         */
 302        while (i <= cnt)
 303                if (look_for_uninteresting
 304                    ? !(sline[i].flag & mark)
 305                    : (sline[i].flag & mark))
 306                        return i;
 307                else
 308                        i++;
 309        return i;
 310}
 311
 312static int give_context(struct sline *sline, unsigned long cnt, int num_parent)
 313{
 314        unsigned long all_mask = (1UL<<num_parent) - 1;
 315        unsigned long mark = (1UL<<num_parent);
 316        unsigned long no_pre_delete = (2UL<<num_parent);
 317        unsigned long i;
 318
 319        /* Two groups of interesting lines may have a short gap of
 320         * uninteresting lines.  Connect such groups to give them a
 321         * bit of context.
 322         *
 323         * We first start from what the interesting() function says,
 324         * and mark them with "mark", and paint context lines with the
 325         * mark.  So interesting() would still say false for such context
 326         * lines but they are treated as "interesting" in the end.
 327         */
 328        i = find_next(sline, mark, 0, cnt, 0);
 329        if (cnt < i)
 330                return 0;
 331
 332        while (i <= cnt) {
 333                unsigned long j = (context < i) ? (i - context) : 0;
 334                unsigned long k;
 335
 336                /* Paint a few lines before the first interesting line. */
 337                while (j < i)
 338                        sline[j++].flag |= mark | no_pre_delete;
 339
 340        again:
 341                /* we know up to i is to be included.  where does the
 342                 * next uninteresting one start?
 343                 */
 344                j = find_next(sline, mark, i, cnt, 1);
 345                if (cnt < j)
 346                        break; /* the rest are all interesting */
 347
 348                /* lookahead context lines */
 349                k = find_next(sline, mark, j, cnt, 0);
 350                j = adjust_hunk_tail(sline, all_mask, i, j);
 351
 352                if (k < j + context) {
 353                        /* k is interesting and [j,k) are not, but
 354                         * paint them interesting because the gap is small.
 355                         */
 356                        while (j < k)
 357                                sline[j++].flag |= mark;
 358                        i = k;
 359                        goto again;
 360                }
 361
 362                /* j is the first uninteresting line and there is
 363                 * no overlap beyond it within context lines.  Paint
 364                 * the trailing edge a bit.
 365                 */
 366                i = k;
 367                k = (j + context < cnt+1) ? j + context : cnt+1;
 368                while (j < k)
 369                        sline[j++].flag |= mark;
 370        }
 371        return 1;
 372}
 373
 374static int make_hunks(struct sline *sline, unsigned long cnt,
 375                       int num_parent, int dense)
 376{
 377        unsigned long all_mask = (1UL<<num_parent) - 1;
 378        unsigned long mark = (1UL<<num_parent);
 379        unsigned long i;
 380        int has_interesting = 0;
 381
 382        for (i = 0; i <= cnt; i++) {
 383                if (interesting(&sline[i], all_mask))
 384                        sline[i].flag |= mark;
 385                else
 386                        sline[i].flag &= ~mark;
 387        }
 388        if (!dense)
 389                return give_context(sline, cnt, num_parent);
 390
 391        /* Look at each hunk, and if we have changes from only one
 392         * parent, or the changes are the same from all but one
 393         * parent, mark that uninteresting.
 394         */
 395        i = 0;
 396        while (i <= cnt) {
 397                unsigned long j, hunk_begin, hunk_end;
 398                unsigned long same_diff;
 399                while (i <= cnt && !(sline[i].flag & mark))
 400                        i++;
 401                if (cnt < i)
 402                        break; /* No more interesting hunks */
 403                hunk_begin = i;
 404                for (j = i + 1; j <= cnt; j++) {
 405                        if (!(sline[j].flag & mark)) {
 406                                /* Look beyond the end to see if there
 407                                 * is an interesting line after this
 408                                 * hunk within context span.
 409                                 */
 410                                unsigned long la; /* lookahead */
 411                                int contin = 0;
 412                                la = adjust_hunk_tail(sline, all_mask,
 413                                                     hunk_begin, j);
 414                                la = (la + context < cnt + 1) ?
 415                                        (la + context) : cnt + 1;
 416                                while (j <= --la) {
 417                                        if (sline[la].flag & mark) {
 418                                                contin = 1;
 419                                                break;
 420                                        }
 421                                }
 422                                if (!contin)
 423                                        break;
 424                                j = la;
 425                        }
 426                }
 427                hunk_end = j;
 428
 429                /* [i..hunk_end) are interesting.  Now is it really
 430                 * interesting?  We check if there are only two versions
 431                 * and the result matches one of them.  That is, we look
 432                 * at:
 433                 *   (+) line, which records lines added to which parents;
 434                 *       this line appears in the result.
 435                 *   (-) line, which records from what parents the line
 436                 *       was removed; this line does not appear in the result.
 437                 * then check the set of parents the result has difference
 438                 * from, from all lines.  If there are lines that has
 439                 * different set of parents that the result has differences
 440                 * from, that means we have more than two versions.
 441                 *
 442                 * Even when we have only two versions, if the result does
 443                 * not match any of the parents, the it should be considered
 444                 * interesting.  In such a case, we would have all '+' line.
 445                 * After passing the above "two versions" test, that would
 446                 * appear as "the same set of parents" to be "all parents".
 447                 */
 448                same_diff = 0;
 449                has_interesting = 0;
 450                for (j = i; j < hunk_end && !has_interesting; j++) {
 451                        unsigned long this_diff = sline[j].flag & all_mask;
 452                        struct lline *ll = sline[j].lost_head;
 453                        if (this_diff) {
 454                                /* This has some changes.  Is it the
 455                                 * same as others?
 456                                 */
 457                                if (!same_diff)
 458                                        same_diff = this_diff;
 459                                else if (same_diff != this_diff) {
 460                                        has_interesting = 1;
 461                                        break;
 462                                }
 463                        }
 464                        while (ll && !has_interesting) {
 465                                /* Lost this line from these parents;
 466                                 * who are they?  Are they the same?
 467                                 */
 468                                this_diff = ll->parent_map;
 469                                if (!same_diff)
 470                                        same_diff = this_diff;
 471                                else if (same_diff != this_diff) {
 472                                        has_interesting = 1;
 473                                }
 474                                ll = ll->next;
 475                        }
 476                }
 477
 478                if (!has_interesting && same_diff != all_mask) {
 479                        /* This hunk is not that interesting after all */
 480                        for (j = hunk_begin; j < hunk_end; j++)
 481                                sline[j].flag &= ~mark;
 482                }
 483                i = hunk_end;
 484        }
 485
 486        has_interesting = give_context(sline, cnt, num_parent);
 487        return has_interesting;
 488}
 489
 490static void show_parent_lno(struct sline *sline, unsigned long l0, unsigned long l1, int n, unsigned long null_context)
 491{
 492        l0 = sline[l0].p_lno[n];
 493        l1 = sline[l1].p_lno[n];
 494        printf(" -%lu,%lu", l0, l1-l0-null_context);
 495}
 496
 497static int hunk_comment_line(const char *bol)
 498{
 499        int ch;
 500
 501        if (!bol)
 502                return 0;
 503        ch = *bol & 0xff;
 504        return (isalpha(ch) || ch == '_' || ch == '$');
 505}
 506
 507static void show_line_to_eol(const char *line, int len, const char *reset)
 508{
 509        int saw_cr_at_eol = 0;
 510        if (len < 0)
 511                len = strlen(line);
 512        saw_cr_at_eol = (len && line[len-1] == '\r');
 513
 514        printf("%.*s%s%s\n", len - saw_cr_at_eol, line,
 515               reset,
 516               saw_cr_at_eol ? "\r" : "");
 517}
 518
 519static void dump_sline(struct sline *sline, unsigned long cnt, int num_parent,
 520                       int use_color)
 521{
 522        unsigned long mark = (1UL<<num_parent);
 523        unsigned long no_pre_delete = (2UL<<num_parent);
 524        int i;
 525        unsigned long lno = 0;
 526        const char *c_frag = diff_get_color(use_color, DIFF_FRAGINFO);
 527        const char *c_new = diff_get_color(use_color, DIFF_FILE_NEW);
 528        const char *c_old = diff_get_color(use_color, DIFF_FILE_OLD);
 529        const char *c_plain = diff_get_color(use_color, DIFF_PLAIN);
 530        const char *c_reset = diff_get_color(use_color, DIFF_RESET);
 531
 532        if (!cnt)
 533                return; /* result deleted */
 534
 535        while (1) {
 536                unsigned long hunk_end;
 537                unsigned long rlines;
 538                const char *hunk_comment = NULL;
 539                unsigned long null_context = 0;
 540
 541                while (lno <= cnt && !(sline[lno].flag & mark)) {
 542                        if (hunk_comment_line(sline[lno].bol))
 543                                hunk_comment = sline[lno].bol;
 544                        lno++;
 545                }
 546                if (cnt < lno)
 547                        break;
 548                else {
 549                        for (hunk_end = lno + 1; hunk_end <= cnt; hunk_end++)
 550                                if (!(sline[hunk_end].flag & mark))
 551                                        break;
 552                }
 553                rlines = hunk_end - lno;
 554                if (cnt < hunk_end)
 555                        rlines--; /* pointing at the last delete hunk */
 556
 557                if (!context) {
 558                        /*
 559                         * Even when running with --unified=0, all
 560                         * lines in the hunk needs to be processed in
 561                         * the loop below in order to show the
 562                         * deletion recorded in lost_head.  However,
 563                         * we do not want to show the resulting line
 564                         * with all blank context markers in such a
 565                         * case.  Compensate.
 566                         */
 567                        unsigned long j;
 568                        for (j = lno; j < hunk_end; j++)
 569                                if (!(sline[j].flag & (mark-1)))
 570                                        null_context++;
 571                        rlines -= null_context;
 572                }
 573
 574                fputs(c_frag, stdout);
 575                for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 576                for (i = 0; i < num_parent; i++)
 577                        show_parent_lno(sline, lno, hunk_end, i, null_context);
 578                printf(" +%lu,%lu ", lno+1, rlines);
 579                for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 580
 581                if (hunk_comment) {
 582                        int comment_end = 0;
 583                        for (i = 0; i < 40; i++) {
 584                                int ch = hunk_comment[i] & 0xff;
 585                                if (!ch || ch == '\n')
 586                                        break;
 587                                if (!isspace(ch))
 588                                    comment_end = i;
 589                        }
 590                        if (comment_end)
 591                                putchar(' ');
 592                        for (i = 0; i < comment_end; i++)
 593                                putchar(hunk_comment[i]);
 594                }
 595
 596                printf("%s\n", c_reset);
 597                while (lno < hunk_end) {
 598                        struct lline *ll;
 599                        int j;
 600                        unsigned long p_mask;
 601                        struct sline *sl = &sline[lno++];
 602                        ll = (sl->flag & no_pre_delete) ? NULL : sl->lost_head;
 603                        while (ll) {
 604                                fputs(c_old, stdout);
 605                                for (j = 0; j < num_parent; j++) {
 606                                        if (ll->parent_map & (1UL<<j))
 607                                                putchar('-');
 608                                        else
 609                                                putchar(' ');
 610                                }
 611                                show_line_to_eol(ll->line, -1, c_reset);
 612                                ll = ll->next;
 613                        }
 614                        if (cnt < lno)
 615                                break;
 616                        p_mask = 1;
 617                        if (!(sl->flag & (mark-1))) {
 618                                /*
 619                                 * This sline was here to hang the
 620                                 * lost lines in front of it.
 621                                 */
 622                                if (!context)
 623                                        continue;
 624                                fputs(c_plain, stdout);
 625                        }
 626                        else
 627                                fputs(c_new, stdout);
 628                        for (j = 0; j < num_parent; j++) {
 629                                if (p_mask & sl->flag)
 630                                        putchar('+');
 631                                else
 632                                        putchar(' ');
 633                                p_mask <<= 1;
 634                        }
 635                        show_line_to_eol(sl->bol, sl->len, c_reset);
 636                }
 637        }
 638}
 639
 640static void reuse_combine_diff(struct sline *sline, unsigned long cnt,
 641                               int i, int j)
 642{
 643        /* We have already examined parent j and we know parent i
 644         * and parent j are the same, so reuse the combined result
 645         * of parent j for parent i.
 646         */
 647        unsigned long lno, imask, jmask;
 648        imask = (1UL<<i);
 649        jmask = (1UL<<j);
 650
 651        for (lno = 0; lno <= cnt; lno++) {
 652                struct lline *ll = sline->lost_head;
 653                sline->p_lno[i] = sline->p_lno[j];
 654                while (ll) {
 655                        if (ll->parent_map & jmask)
 656                                ll->parent_map |= imask;
 657                        ll = ll->next;
 658                }
 659                if (sline->flag & jmask)
 660                        sline->flag |= imask;
 661                sline++;
 662        }
 663        /* the overall size of the file (sline[cnt]) */
 664        sline->p_lno[i] = sline->p_lno[j];
 665}
 666
 667static void dump_quoted_path(const char *head,
 668                             const char *prefix,
 669                             const char *path,
 670                             const char *c_meta, const char *c_reset)
 671{
 672        static struct strbuf buf = STRBUF_INIT;
 673
 674        strbuf_reset(&buf);
 675        strbuf_addstr(&buf, c_meta);
 676        strbuf_addstr(&buf, head);
 677        quote_two_c_style(&buf, prefix, path, 0);
 678        strbuf_addstr(&buf, c_reset);
 679        puts(buf.buf);
 680}
 681
 682static void show_patch_diff(struct combine_diff_path *elem, int num_parent,
 683                            int dense, struct rev_info *rev)
 684{
 685        struct diff_options *opt = &rev->diffopt;
 686        unsigned long result_size, cnt, lno;
 687        char *result, *cp;
 688        struct sline *sline; /* survived lines */
 689        int mode_differs = 0;
 690        int i, show_hunks;
 691        int working_tree_file = is_null_sha1(elem->sha1);
 692        int abbrev = DIFF_OPT_TST(opt, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
 693        const char *a_prefix, *b_prefix;
 694        mmfile_t result_file;
 695
 696        context = opt->context;
 697        a_prefix = opt->a_prefix ? opt->a_prefix : "a/";
 698        b_prefix = opt->b_prefix ? opt->b_prefix : "b/";
 699
 700        /* Read the result of merge first */
 701        if (!working_tree_file)
 702                result = grab_blob(elem->sha1, elem->mode, &result_size);
 703        else {
 704                /* Used by diff-tree to read from the working tree */
 705                struct stat st;
 706                int fd = -1;
 707
 708                if (lstat(elem->path, &st) < 0)
 709                        goto deleted_file;
 710
 711                if (S_ISLNK(st.st_mode)) {
 712                        struct strbuf buf = STRBUF_INIT;
 713
 714                        if (strbuf_readlink(&buf, elem->path, st.st_size) < 0) {
 715                                error("readlink(%s): %s", elem->path,
 716                                      strerror(errno));
 717                                return;
 718                        }
 719                        result_size = buf.len;
 720                        result = strbuf_detach(&buf, NULL);
 721                        elem->mode = canon_mode(st.st_mode);
 722                } else if (S_ISDIR(st.st_mode)) {
 723                        unsigned char sha1[20];
 724                        if (resolve_gitlink_ref(elem->path, "HEAD", sha1) < 0)
 725                                result = grab_blob(elem->sha1, elem->mode, &result_size);
 726                        else
 727                                result = grab_blob(sha1, elem->mode, &result_size);
 728                } else if (0 <= (fd = open(elem->path, O_RDONLY))) {
 729                        size_t len = xsize_t(st.st_size);
 730                        ssize_t done;
 731                        int is_file, i;
 732
 733                        elem->mode = canon_mode(st.st_mode);
 734                        /* if symlinks don't work, assume symlink if all parents
 735                         * are symlinks
 736                         */
 737                        is_file = has_symlinks;
 738                        for (i = 0; !is_file && i < num_parent; i++)
 739                                is_file = !S_ISLNK(elem->parent[i].mode);
 740                        if (!is_file)
 741                                elem->mode = canon_mode(S_IFLNK);
 742
 743                        result_size = len;
 744                        result = xmalloc(len + 1);
 745
 746                        done = read_in_full(fd, result, len);
 747                        if (done < 0)
 748                                die_errno("read error '%s'", elem->path);
 749                        else if (done < len)
 750                                die("early EOF '%s'", elem->path);
 751
 752                        result[len] = 0;
 753
 754                        /* If not a fake symlink, apply filters, e.g. autocrlf */
 755                        if (is_file) {
 756                                struct strbuf buf = STRBUF_INIT;
 757
 758                                if (convert_to_git(elem->path, result, len, &buf, safe_crlf)) {
 759                                        free(result);
 760                                        result = strbuf_detach(&buf, &len);
 761                                        result_size = len;
 762                                }
 763                        }
 764                }
 765                else {
 766                deleted_file:
 767                        result_size = 0;
 768                        elem->mode = 0;
 769                        result = xcalloc(1, 1);
 770                }
 771
 772                if (0 <= fd)
 773                        close(fd);
 774        }
 775
 776        for (cnt = 0, cp = result; cp < result + result_size; cp++) {
 777                if (*cp == '\n')
 778                        cnt++;
 779        }
 780        if (result_size && result[result_size-1] != '\n')
 781                cnt++; /* incomplete line */
 782
 783        sline = xcalloc(cnt+2, sizeof(*sline));
 784        sline[0].bol = result;
 785        for (lno = 0; lno <= cnt + 1; lno++) {
 786                sline[lno].lost_tail = &sline[lno].lost_head;
 787                sline[lno].flag = 0;
 788        }
 789        for (lno = 0, cp = result; cp < result + result_size; cp++) {
 790                if (*cp == '\n') {
 791                        sline[lno].len = cp - sline[lno].bol;
 792                        lno++;
 793                        if (lno < cnt)
 794                                sline[lno].bol = cp + 1;
 795                }
 796        }
 797        if (result_size && result[result_size-1] != '\n')
 798                sline[cnt-1].len = result_size - (sline[cnt-1].bol - result);
 799
 800        result_file.ptr = result;
 801        result_file.size = result_size;
 802
 803        /* Even p_lno[cnt+1] is valid -- that is for the end line number
 804         * for deletion hunk at the end.
 805         */
 806        sline[0].p_lno = xcalloc((cnt+2) * num_parent, sizeof(unsigned long));
 807        for (lno = 0; lno <= cnt; lno++)
 808                sline[lno+1].p_lno = sline[lno].p_lno + num_parent;
 809
 810        for (i = 0; i < num_parent; i++) {
 811                int j;
 812                for (j = 0; j < i; j++) {
 813                        if (!hashcmp(elem->parent[i].sha1,
 814                                     elem->parent[j].sha1)) {
 815                                reuse_combine_diff(sline, cnt, i, j);
 816                                break;
 817                        }
 818                }
 819                if (i <= j)
 820                        combine_diff(elem->parent[i].sha1,
 821                                     elem->parent[i].mode,
 822                                     &result_file, sline,
 823                                     cnt, i, num_parent);
 824                if (elem->parent[i].mode != elem->mode)
 825                        mode_differs = 1;
 826        }
 827
 828        show_hunks = make_hunks(sline, cnt, num_parent, dense);
 829
 830        if (show_hunks || mode_differs || working_tree_file) {
 831                const char *abb;
 832                int use_color = DIFF_OPT_TST(opt, COLOR_DIFF);
 833                const char *c_meta = diff_get_color(use_color, DIFF_METAINFO);
 834                const char *c_reset = diff_get_color(use_color, DIFF_RESET);
 835                int added = 0;
 836                int deleted = 0;
 837
 838                if (rev->loginfo && !rev->no_commit_id)
 839                        show_log(rev);
 840                dump_quoted_path(dense ? "diff --cc " : "diff --combined ",
 841                                 "", elem->path, c_meta, c_reset);
 842                printf("%sindex ", c_meta);
 843                for (i = 0; i < num_parent; i++) {
 844                        abb = find_unique_abbrev(elem->parent[i].sha1,
 845                                                 abbrev);
 846                        printf("%s%s", i ? "," : "", abb);
 847                }
 848                abb = find_unique_abbrev(elem->sha1, abbrev);
 849                printf("..%s%s\n", abb, c_reset);
 850
 851                if (mode_differs) {
 852                        deleted = !elem->mode;
 853
 854                        /* We say it was added if nobody had it */
 855                        added = !deleted;
 856                        for (i = 0; added && i < num_parent; i++)
 857                                if (elem->parent[i].status !=
 858                                    DIFF_STATUS_ADDED)
 859                                        added = 0;
 860                        if (added)
 861                                printf("%snew file mode %06o",
 862                                       c_meta, elem->mode);
 863                        else {
 864                                if (deleted)
 865                                        printf("%sdeleted file ", c_meta);
 866                                printf("mode ");
 867                                for (i = 0; i < num_parent; i++) {
 868                                        printf("%s%06o", i ? "," : "",
 869                                               elem->parent[i].mode);
 870                                }
 871                                if (elem->mode)
 872                                        printf("..%06o", elem->mode);
 873                        }
 874                        printf("%s\n", c_reset);
 875                }
 876                if (added)
 877                        dump_quoted_path("--- ", "", "/dev/null",
 878                                         c_meta, c_reset);
 879                else
 880                        dump_quoted_path("--- ", a_prefix, elem->path,
 881                                         c_meta, c_reset);
 882                if (deleted)
 883                        dump_quoted_path("+++ ", "", "/dev/null",
 884                                         c_meta, c_reset);
 885                else
 886                        dump_quoted_path("+++ ", b_prefix, elem->path,
 887                                         c_meta, c_reset);
 888                dump_sline(sline, cnt, num_parent,
 889                           DIFF_OPT_TST(opt, COLOR_DIFF));
 890        }
 891        free(result);
 892
 893        for (lno = 0; lno < cnt; lno++) {
 894                if (sline[lno].lost_head) {
 895                        struct lline *ll = sline[lno].lost_head;
 896                        while (ll) {
 897                                struct lline *tmp = ll;
 898                                ll = ll->next;
 899                                free(tmp);
 900                        }
 901                }
 902        }
 903        free(sline[0].p_lno);
 904        free(sline);
 905}
 906
 907#define COLONS "::::::::::::::::::::::::::::::::"
 908
 909static void show_raw_diff(struct combine_diff_path *p, int num_parent, struct rev_info *rev)
 910{
 911        struct diff_options *opt = &rev->diffopt;
 912        int i, offset;
 913        const char *prefix;
 914        int line_termination, inter_name_termination;
 915
 916        line_termination = opt->line_termination;
 917        inter_name_termination = '\t';
 918        if (!line_termination)
 919                inter_name_termination = 0;
 920
 921        if (rev->loginfo && !rev->no_commit_id)
 922                show_log(rev);
 923
 924        if (opt->output_format & DIFF_FORMAT_RAW) {
 925                offset = strlen(COLONS) - num_parent;
 926                if (offset < 0)
 927                        offset = 0;
 928                prefix = COLONS + offset;
 929
 930                /* Show the modes */
 931                for (i = 0; i < num_parent; i++) {
 932                        printf("%s%06o", prefix, p->parent[i].mode);
 933                        prefix = " ";
 934                }
 935                printf("%s%06o", prefix, p->mode);
 936
 937                /* Show sha1's */
 938                for (i = 0; i < num_parent; i++)
 939                        printf(" %s", diff_unique_abbrev(p->parent[i].sha1,
 940                                                         opt->abbrev));
 941                printf(" %s ", diff_unique_abbrev(p->sha1, opt->abbrev));
 942        }
 943
 944        if (opt->output_format & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS)) {
 945                for (i = 0; i < num_parent; i++)
 946                        putchar(p->parent[i].status);
 947                putchar(inter_name_termination);
 948        }
 949
 950        write_name_quoted(p->path, stdout, line_termination);
 951}
 952
 953void show_combined_diff(struct combine_diff_path *p,
 954                       int num_parent,
 955                       int dense,
 956                       struct rev_info *rev)
 957{
 958        struct diff_options *opt = &rev->diffopt;
 959        if (!p->len)
 960                return;
 961        if (opt->output_format & (DIFF_FORMAT_RAW |
 962                                  DIFF_FORMAT_NAME |
 963                                  DIFF_FORMAT_NAME_STATUS))
 964                show_raw_diff(p, num_parent, rev);
 965        else if (opt->output_format & DIFF_FORMAT_PATCH)
 966                show_patch_diff(p, num_parent, dense, rev);
 967}
 968
 969void diff_tree_combined(const unsigned char *sha1,
 970                        const unsigned char parent[][20],
 971                        int num_parent,
 972                        int dense,
 973                        struct rev_info *rev)
 974{
 975        struct diff_options *opt = &rev->diffopt;
 976        struct diff_options diffopts;
 977        struct combine_diff_path *p, *paths = NULL;
 978        int i, num_paths, needsep, show_log_first;
 979
 980        diffopts = *opt;
 981        diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
 982        DIFF_OPT_SET(&diffopts, RECURSIVE);
 983        DIFF_OPT_CLR(&diffopts, ALLOW_EXTERNAL);
 984
 985        show_log_first = !!rev->loginfo && !rev->no_commit_id;
 986        needsep = 0;
 987        /* find set of paths that everybody touches */
 988        for (i = 0; i < num_parent; i++) {
 989                /* show stat against the first parent even
 990                 * when doing combined diff.
 991                 */
 992                int stat_opt = (opt->output_format &
 993                                (DIFF_FORMAT_NUMSTAT|DIFF_FORMAT_DIFFSTAT));
 994                if (i == 0 && stat_opt)
 995                        diffopts.output_format = stat_opt;
 996                else
 997                        diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
 998                diff_tree_sha1(parent[i], sha1, "", &diffopts);
 999                diffcore_std(&diffopts);
1000                paths = intersect_paths(paths, i, num_parent);
1001
1002                if (show_log_first && i == 0) {
1003                        show_log(rev);
1004                        if (rev->verbose_header && opt->output_format)
1005                                putchar(opt->line_termination);
1006                }
1007                diff_flush(&diffopts);
1008        }
1009
1010        /* find out surviving paths */
1011        for (num_paths = 0, p = paths; p; p = p->next) {
1012                if (p->len)
1013                        num_paths++;
1014        }
1015        if (num_paths) {
1016                if (opt->output_format & (DIFF_FORMAT_RAW |
1017                                          DIFF_FORMAT_NAME |
1018                                          DIFF_FORMAT_NAME_STATUS)) {
1019                        for (p = paths; p; p = p->next) {
1020                                if (p->len)
1021                                        show_raw_diff(p, num_parent, rev);
1022                        }
1023                        needsep = 1;
1024                }
1025                else if (opt->output_format &
1026                         (DIFF_FORMAT_NUMSTAT|DIFF_FORMAT_DIFFSTAT))
1027                        needsep = 1;
1028                if (opt->output_format & DIFF_FORMAT_PATCH) {
1029                        if (needsep)
1030                                putchar(opt->line_termination);
1031                        for (p = paths; p; p = p->next) {
1032                                if (p->len)
1033                                        show_patch_diff(p, num_parent, dense,
1034                                                        rev);
1035                        }
1036                }
1037        }
1038
1039        /* Clean things up */
1040        while (paths) {
1041                struct combine_diff_path *tmp = paths;
1042                paths = paths->next;
1043                free(tmp);
1044        }
1045}
1046
1047void diff_tree_combined_merge(const unsigned char *sha1,
1048                             int dense, struct rev_info *rev)
1049{
1050        int num_parent;
1051        const unsigned char (*parent)[20];
1052        struct commit *commit = lookup_commit(sha1);
1053        struct commit_list *parents;
1054
1055        /* count parents */
1056        for (parents = commit->parents, num_parent = 0;
1057             parents;
1058             parents = parents->next, num_parent++)
1059                ; /* nothing */
1060
1061        parent = xmalloc(num_parent * sizeof(*parent));
1062        for (parents = commit->parents, num_parent = 0;
1063             parents;
1064             parents = parents->next, num_parent++)
1065                hashcpy((unsigned char *)(parent + num_parent),
1066                        parents->item->object.sha1);
1067        diff_tree_combined(sha1, parent, num_parent, dense, rev);
1068}