combine-diff.con commit Fix neglect of diff_setup()/diff_setup_done() symmetry. (e752f4b)
   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        unsigned int lno;
 147        int ob, on, nb, nn;
 148        unsigned long nmask;
 149        int num_parent;
 150        int n;
 151        struct sline *sline;
 152        struct sline *lost_bucket;
 153};
 154
 155static void consume_line(void *state_, char *line, unsigned long len)
 156{
 157        struct combine_diff_state *state = state_;
 158        if (5 < len && !memcmp("@@ -", line, 4)) {
 159                if (parse_hunk_header(line, len,
 160                                      &state->ob, &state->on,
 161                                      &state->nb, &state->nn))
 162                        return;
 163                state->lno = state->nb;
 164                if (!state->nb)
 165                        /* @@ -1,2 +0,0 @@ to remove the
 166                         * first two lines...
 167                         */
 168                        state->nb = 1;
 169                if (state->nn == 0)
 170                        /* @@ -X,Y +N,0 @@ removed Y lines
 171                         * that would have come *after* line N
 172                         * in the result.  Our lost buckets hang
 173                         * to the line after the removed lines,
 174                         */
 175                        state->lost_bucket = &state->sline[state->nb];
 176                else
 177                        state->lost_bucket = &state->sline[state->nb-1];
 178                if (!state->sline[state->nb-1].p_lno)
 179                        state->sline[state->nb-1].p_lno =
 180                                xcalloc(state->num_parent,
 181                                        sizeof(unsigned long));
 182                state->sline[state->nb-1].p_lno[state->n] = state->ob;
 183                return;
 184        }
 185        if (!state->lost_bucket)
 186                return; /* not in any hunk yet */
 187        switch (line[0]) {
 188        case '-':
 189                append_lost(state->lost_bucket, state->n, line+1, len-1);
 190                break;
 191        case '+':
 192                state->sline[state->lno-1].flag |= state->nmask;
 193                state->lno++;
 194                break;
 195        }
 196}
 197
 198static void combine_diff(const unsigned char *parent, mmfile_t *result_file,
 199                         struct sline *sline, unsigned int cnt, int n,
 200                         int num_parent)
 201{
 202        unsigned int p_lno, lno;
 203        unsigned long nmask = (1UL << n);
 204        xpparam_t xpp;
 205        xdemitconf_t xecfg;
 206        mmfile_t parent_file;
 207        xdemitcb_t ecb;
 208        struct combine_diff_state state;
 209        unsigned long sz;
 210
 211        if (!cnt)
 212                return; /* result deleted */
 213
 214        parent_file.ptr = grab_blob(parent, &sz);
 215        parent_file.size = sz;
 216        memset(&xpp, 0, sizeof(xpp));
 217        xpp.flags = XDF_NEED_MINIMAL;
 218        memset(&xecfg, 0, sizeof(xecfg));
 219        memset(&state, 0, sizeof(state));
 220        state.nmask = nmask;
 221        state.sline = sline;
 222        state.lno = 1;
 223        state.num_parent = num_parent;
 224        state.n = n;
 225
 226        xdi_diff_outf(&parent_file, result_file, consume_line, &state,
 227                      &xpp, &xecfg, &ecb);
 228        free(parent_file.ptr);
 229
 230        /* Assign line numbers for this parent.
 231         *
 232         * sline[lno].p_lno[n] records the first line number
 233         * (counting from 1) for parent N if the final hunk display
 234         * started by showing sline[lno] (possibly showing the lost
 235         * lines attached to it first).
 236         */
 237        for (lno = 0,  p_lno = 1; lno <= cnt; lno++) {
 238                struct lline *ll;
 239                sline[lno].p_lno[n] = p_lno;
 240
 241                /* How many lines would this sline advance the p_lno? */
 242                ll = sline[lno].lost_head;
 243                while (ll) {
 244                        if (ll->parent_map & nmask)
 245                                p_lno++; /* '-' means parent had it */
 246                        ll = ll->next;
 247                }
 248                if (lno < cnt && !(sline[lno].flag & nmask))
 249                        p_lno++; /* no '+' means parent had it */
 250        }
 251        sline[lno].p_lno[n] = p_lno; /* trailer */
 252}
 253
 254static unsigned long context = 3;
 255static char combine_marker = '@';
 256
 257static int interesting(struct sline *sline, unsigned long all_mask)
 258{
 259        /* If some parents lost lines here, or if we have added to
 260         * some parent, it is interesting.
 261         */
 262        return ((sline->flag & all_mask) || sline->lost_head);
 263}
 264
 265static unsigned long adjust_hunk_tail(struct sline *sline,
 266                                      unsigned long all_mask,
 267                                      unsigned long hunk_begin,
 268                                      unsigned long i)
 269{
 270        /* i points at the first uninteresting line.  If the last line
 271         * of the hunk was interesting only because it has some
 272         * deletion, then it is not all that interesting for the
 273         * purpose of giving trailing context lines.  This is because
 274         * we output '-' line and then unmodified sline[i-1] itself in
 275         * that case which gives us one extra context line.
 276         */
 277        if ((hunk_begin + 1 <= i) && !(sline[i-1].flag & all_mask))
 278                i--;
 279        return i;
 280}
 281
 282static unsigned long find_next(struct sline *sline,
 283                               unsigned long mark,
 284                               unsigned long i,
 285                               unsigned long cnt,
 286                               int look_for_uninteresting)
 287{
 288        /* We have examined up to i-1 and are about to look at i.
 289         * Find next interesting or uninteresting line.  Here,
 290         * "interesting" does not mean interesting(), but marked by
 291         * the give_context() function below (i.e. it includes context
 292         * lines that are not interesting to interesting() function
 293         * that are surrounded by interesting() ones.
 294         */
 295        while (i <= cnt)
 296                if (look_for_uninteresting
 297                    ? !(sline[i].flag & mark)
 298                    : (sline[i].flag & mark))
 299                        return i;
 300                else
 301                        i++;
 302        return i;
 303}
 304
 305static int give_context(struct sline *sline, unsigned long cnt, int num_parent)
 306{
 307        unsigned long all_mask = (1UL<<num_parent) - 1;
 308        unsigned long mark = (1UL<<num_parent);
 309        unsigned long no_pre_delete = (2UL<<num_parent);
 310        unsigned long i;
 311
 312        /* Two groups of interesting lines may have a short gap of
 313         * uninteresting lines.  Connect such groups to give them a
 314         * bit of context.
 315         *
 316         * We first start from what the interesting() function says,
 317         * and mark them with "mark", and paint context lines with the
 318         * mark.  So interesting() would still say false for such context
 319         * lines but they are treated as "interesting" in the end.
 320         */
 321        i = find_next(sline, mark, 0, cnt, 0);
 322        if (cnt < i)
 323                return 0;
 324
 325        while (i <= cnt) {
 326                unsigned long j = (context < i) ? (i - context) : 0;
 327                unsigned long k;
 328
 329                /* Paint a few lines before the first interesting line. */
 330                while (j < i)
 331                        sline[j++].flag |= mark | no_pre_delete;
 332
 333        again:
 334                /* we know up to i is to be included.  where does the
 335                 * next uninteresting one start?
 336                 */
 337                j = find_next(sline, mark, i, cnt, 1);
 338                if (cnt < j)
 339                        break; /* the rest are all interesting */
 340
 341                /* lookahead context lines */
 342                k = find_next(sline, mark, j, cnt, 0);
 343                j = adjust_hunk_tail(sline, all_mask, i, j);
 344
 345                if (k < j + context) {
 346                        /* k is interesting and [j,k) are not, but
 347                         * paint them interesting because the gap is small.
 348                         */
 349                        while (j < k)
 350                                sline[j++].flag |= mark;
 351                        i = k;
 352                        goto again;
 353                }
 354
 355                /* j is the first uninteresting line and there is
 356                 * no overlap beyond it within context lines.  Paint
 357                 * the trailing edge a bit.
 358                 */
 359                i = k;
 360                k = (j + context < cnt+1) ? j + context : cnt+1;
 361                while (j < k)
 362                        sline[j++].flag |= mark;
 363        }
 364        return 1;
 365}
 366
 367static int make_hunks(struct sline *sline, unsigned long cnt,
 368                       int num_parent, int dense)
 369{
 370        unsigned long all_mask = (1UL<<num_parent) - 1;
 371        unsigned long mark = (1UL<<num_parent);
 372        unsigned long i;
 373        int has_interesting = 0;
 374
 375        for (i = 0; i <= cnt; i++) {
 376                if (interesting(&sline[i], all_mask))
 377                        sline[i].flag |= mark;
 378                else
 379                        sline[i].flag &= ~mark;
 380        }
 381        if (!dense)
 382                return give_context(sline, cnt, num_parent);
 383
 384        /* Look at each hunk, and if we have changes from only one
 385         * parent, or the changes are the same from all but one
 386         * parent, mark that uninteresting.
 387         */
 388        i = 0;
 389        while (i <= cnt) {
 390                unsigned long j, hunk_begin, hunk_end;
 391                unsigned long same_diff;
 392                while (i <= cnt && !(sline[i].flag & mark))
 393                        i++;
 394                if (cnt < i)
 395                        break; /* No more interesting hunks */
 396                hunk_begin = i;
 397                for (j = i + 1; j <= cnt; j++) {
 398                        if (!(sline[j].flag & mark)) {
 399                                /* Look beyond the end to see if there
 400                                 * is an interesting line after this
 401                                 * hunk within context span.
 402                                 */
 403                                unsigned long la; /* lookahead */
 404                                int contin = 0;
 405                                la = adjust_hunk_tail(sline, all_mask,
 406                                                     hunk_begin, j);
 407                                la = (la + context < cnt + 1) ?
 408                                        (la + context) : cnt + 1;
 409                                while (j <= --la) {
 410                                        if (sline[la].flag & mark) {
 411                                                contin = 1;
 412                                                break;
 413                                        }
 414                                }
 415                                if (!contin)
 416                                        break;
 417                                j = la;
 418                        }
 419                }
 420                hunk_end = j;
 421
 422                /* [i..hunk_end) are interesting.  Now is it really
 423                 * interesting?  We check if there are only two versions
 424                 * and the result matches one of them.  That is, we look
 425                 * at:
 426                 *   (+) line, which records lines added to which parents;
 427                 *       this line appears in the result.
 428                 *   (-) line, which records from what parents the line
 429                 *       was removed; this line does not appear in the result.
 430                 * then check the set of parents the result has difference
 431                 * from, from all lines.  If there are lines that has
 432                 * different set of parents that the result has differences
 433                 * from, that means we have more than two versions.
 434                 *
 435                 * Even when we have only two versions, if the result does
 436                 * not match any of the parents, the it should be considered
 437                 * interesting.  In such a case, we would have all '+' line.
 438                 * After passing the above "two versions" test, that would
 439                 * appear as "the same set of parents" to be "all parents".
 440                 */
 441                same_diff = 0;
 442                has_interesting = 0;
 443                for (j = i; j < hunk_end && !has_interesting; j++) {
 444                        unsigned long this_diff = sline[j].flag & all_mask;
 445                        struct lline *ll = sline[j].lost_head;
 446                        if (this_diff) {
 447                                /* This has some changes.  Is it the
 448                                 * same as others?
 449                                 */
 450                                if (!same_diff)
 451                                        same_diff = this_diff;
 452                                else if (same_diff != this_diff) {
 453                                        has_interesting = 1;
 454                                        break;
 455                                }
 456                        }
 457                        while (ll && !has_interesting) {
 458                                /* Lost this line from these parents;
 459                                 * who are they?  Are they the same?
 460                                 */
 461                                this_diff = ll->parent_map;
 462                                if (!same_diff)
 463                                        same_diff = this_diff;
 464                                else if (same_diff != this_diff) {
 465                                        has_interesting = 1;
 466                                }
 467                                ll = ll->next;
 468                        }
 469                }
 470
 471                if (!has_interesting && same_diff != all_mask) {
 472                        /* This hunk is not that interesting after all */
 473                        for (j = hunk_begin; j < hunk_end; j++)
 474                                sline[j].flag &= ~mark;
 475                }
 476                i = hunk_end;
 477        }
 478
 479        has_interesting = give_context(sline, cnt, num_parent);
 480        return has_interesting;
 481}
 482
 483static void show_parent_lno(struct sline *sline, unsigned long l0, unsigned long l1, int n, unsigned long null_context)
 484{
 485        l0 = sline[l0].p_lno[n];
 486        l1 = sline[l1].p_lno[n];
 487        printf(" -%lu,%lu", l0, l1-l0-null_context);
 488}
 489
 490static int hunk_comment_line(const char *bol)
 491{
 492        int ch;
 493
 494        if (!bol)
 495                return 0;
 496        ch = *bol & 0xff;
 497        return (isalpha(ch) || ch == '_' || ch == '$');
 498}
 499
 500static void show_line_to_eol(const char *line, int len, const char *reset)
 501{
 502        int saw_cr_at_eol = 0;
 503        if (len < 0)
 504                len = strlen(line);
 505        saw_cr_at_eol = (len && line[len-1] == '\r');
 506
 507        printf("%.*s%s%s\n", len - saw_cr_at_eol, line,
 508               reset,
 509               saw_cr_at_eol ? "\r" : "");
 510}
 511
 512static void dump_sline(struct sline *sline, unsigned long cnt, int num_parent,
 513                       int use_color)
 514{
 515        unsigned long mark = (1UL<<num_parent);
 516        unsigned long no_pre_delete = (2UL<<num_parent);
 517        int i;
 518        unsigned long lno = 0;
 519        const char *c_frag = diff_get_color(use_color, DIFF_FRAGINFO);
 520        const char *c_new = diff_get_color(use_color, DIFF_FILE_NEW);
 521        const char *c_old = diff_get_color(use_color, DIFF_FILE_OLD);
 522        const char *c_plain = diff_get_color(use_color, DIFF_PLAIN);
 523        const char *c_reset = diff_get_color(use_color, DIFF_RESET);
 524
 525        if (!cnt)
 526                return; /* result deleted */
 527
 528        while (1) {
 529                struct sline *sl = &sline[lno];
 530                unsigned long hunk_end;
 531                unsigned long rlines;
 532                const char *hunk_comment = NULL;
 533                unsigned long null_context = 0;
 534
 535                while (lno <= cnt && !(sline[lno].flag & mark)) {
 536                        if (hunk_comment_line(sline[lno].bol))
 537                                hunk_comment = sline[lno].bol;
 538                        lno++;
 539                }
 540                if (cnt < lno)
 541                        break;
 542                else {
 543                        for (hunk_end = lno + 1; hunk_end <= cnt; hunk_end++)
 544                                if (!(sline[hunk_end].flag & mark))
 545                                        break;
 546                }
 547                rlines = hunk_end - lno;
 548                if (cnt < hunk_end)
 549                        rlines--; /* pointing at the last delete hunk */
 550
 551                if (!context) {
 552                        /*
 553                         * Even when running with --unified=0, all
 554                         * lines in the hunk needs to be processed in
 555                         * the loop below in order to show the
 556                         * deletion recorded in lost_head.  However,
 557                         * we do not want to show the resulting line
 558                         * with all blank context markers in such a
 559                         * case.  Compensate.
 560                         */
 561                        unsigned long j;
 562                        for (j = lno; j < hunk_end; j++)
 563                                if (!(sline[j].flag & (mark-1)))
 564                                        null_context++;
 565                        rlines -= null_context;
 566                }
 567
 568                fputs(c_frag, stdout);
 569                for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 570                for (i = 0; i < num_parent; i++)
 571                        show_parent_lno(sline, lno, hunk_end, i, null_context);
 572                printf(" +%lu,%lu ", lno+1, rlines);
 573                for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 574
 575                if (hunk_comment) {
 576                        int comment_end = 0;
 577                        for (i = 0; i < 40; i++) {
 578                                int ch = hunk_comment[i] & 0xff;
 579                                if (!ch || ch == '\n')
 580                                        break;
 581                                if (!isspace(ch))
 582                                    comment_end = i;
 583                        }
 584                        if (comment_end)
 585                                putchar(' ');
 586                        for (i = 0; i < comment_end; i++)
 587                                putchar(hunk_comment[i]);
 588                }
 589
 590                printf("%s\n", c_reset);
 591                while (lno < hunk_end) {
 592                        struct lline *ll;
 593                        int j;
 594                        unsigned long p_mask;
 595                        sl = &sline[lno++];
 596                        ll = (sl->flag & no_pre_delete) ? NULL : sl->lost_head;
 597                        while (ll) {
 598                                fputs(c_old, stdout);
 599                                for (j = 0; j < num_parent; j++) {
 600                                        if (ll->parent_map & (1UL<<j))
 601                                                putchar('-');
 602                                        else
 603                                                putchar(' ');
 604                                }
 605                                show_line_to_eol(ll->line, -1, c_reset);
 606                                ll = ll->next;
 607                        }
 608                        if (cnt < lno)
 609                                break;
 610                        p_mask = 1;
 611                        if (!(sl->flag & (mark-1))) {
 612                                /*
 613                                 * This sline was here to hang the
 614                                 * lost lines in front of it.
 615                                 */
 616                                if (!context)
 617                                        continue;
 618                                fputs(c_plain, stdout);
 619                        }
 620                        else
 621                                fputs(c_new, stdout);
 622                        for (j = 0; j < num_parent; j++) {
 623                                if (p_mask & sl->flag)
 624                                        putchar('+');
 625                                else
 626                                        putchar(' ');
 627                                p_mask <<= 1;
 628                        }
 629                        show_line_to_eol(sl->bol, sl->len, c_reset);
 630                }
 631        }
 632}
 633
 634static void reuse_combine_diff(struct sline *sline, unsigned long cnt,
 635                               int i, int j)
 636{
 637        /* We have already examined parent j and we know parent i
 638         * and parent j are the same, so reuse the combined result
 639         * of parent j for parent i.
 640         */
 641        unsigned long lno, imask, jmask;
 642        imask = (1UL<<i);
 643        jmask = (1UL<<j);
 644
 645        for (lno = 0; lno <= cnt; lno++) {
 646                struct lline *ll = sline->lost_head;
 647                sline->p_lno[i] = sline->p_lno[j];
 648                while (ll) {
 649                        if (ll->parent_map & jmask)
 650                                ll->parent_map |= imask;
 651                        ll = ll->next;
 652                }
 653                if (sline->flag & jmask)
 654                        sline->flag |= imask;
 655                sline++;
 656        }
 657        /* the overall size of the file (sline[cnt]) */
 658        sline->p_lno[i] = sline->p_lno[j];
 659}
 660
 661static void dump_quoted_path(const char *head,
 662                             const char *prefix,
 663                             const char *path,
 664                             const char *c_meta, const char *c_reset)
 665{
 666        static struct strbuf buf = STRBUF_INIT;
 667
 668        strbuf_reset(&buf);
 669        strbuf_addstr(&buf, c_meta);
 670        strbuf_addstr(&buf, head);
 671        quote_two_c_style(&buf, prefix, path, 0);
 672        strbuf_addstr(&buf, c_reset);
 673        puts(buf.buf);
 674}
 675
 676static void show_patch_diff(struct combine_diff_path *elem, int num_parent,
 677                            int dense, struct rev_info *rev)
 678{
 679        struct diff_options *opt = &rev->diffopt;
 680        unsigned long result_size, cnt, lno;
 681        char *result, *cp;
 682        struct sline *sline; /* survived lines */
 683        int mode_differs = 0;
 684        int i, show_hunks;
 685        int working_tree_file = is_null_sha1(elem->sha1);
 686        int abbrev = DIFF_OPT_TST(opt, FULL_INDEX) ? 40 : DEFAULT_ABBREV;
 687        const char *a_prefix, *b_prefix;
 688        mmfile_t result_file;
 689
 690        context = opt->context;
 691        a_prefix = opt->a_prefix ? opt->a_prefix : "a/";
 692        b_prefix = opt->b_prefix ? opt->b_prefix : "b/";
 693
 694        /* Read the result of merge first */
 695        if (!working_tree_file)
 696                result = grab_blob(elem->sha1, &result_size);
 697        else {
 698                /* Used by diff-tree to read from the working tree */
 699                struct stat st;
 700                int fd = -1;
 701
 702                if (lstat(elem->path, &st) < 0)
 703                        goto deleted_file;
 704
 705                if (S_ISLNK(st.st_mode)) {
 706                        struct strbuf buf = STRBUF_INIT;
 707
 708                        if (strbuf_readlink(&buf, elem->path, st.st_size) < 0) {
 709                                error("readlink(%s): %s", elem->path,
 710                                      strerror(errno));
 711                                return;
 712                        }
 713                        result_size = buf.len;
 714                        result = strbuf_detach(&buf, NULL);
 715                        elem->mode = canon_mode(st.st_mode);
 716                }
 717                else if (0 <= (fd = open(elem->path, O_RDONLY)) &&
 718                         !fstat(fd, &st)) {
 719                        size_t len = xsize_t(st.st_size);
 720                        ssize_t done;
 721                        int is_file, i;
 722
 723                        elem->mode = canon_mode(st.st_mode);
 724                        /* if symlinks don't work, assume symlink if all parents
 725                         * are symlinks
 726                         */
 727                        is_file = has_symlinks;
 728                        for (i = 0; !is_file && i < num_parent; i++)
 729                                is_file = !S_ISLNK(elem->parent[i].mode);
 730                        if (!is_file)
 731                                elem->mode = canon_mode(S_IFLNK);
 732
 733                        result_size = len;
 734                        result = xmalloc(len + 1);
 735
 736                        done = read_in_full(fd, result, len);
 737                        if (done < 0)
 738                                die("read error '%s'", elem->path);
 739                        else if (done < len)
 740                                die("early EOF '%s'", elem->path);
 741
 742                        result[len] = 0;
 743
 744                        /* If not a fake symlink, apply filters, e.g. autocrlf */
 745                        if (is_file) {
 746                                struct strbuf buf = STRBUF_INIT;
 747
 748                                if (convert_to_git(elem->path, result, len, &buf, safe_crlf)) {
 749                                        free(result);
 750                                        result = strbuf_detach(&buf, &len);
 751                                        result_size = len;
 752                                }
 753                        }
 754                }
 755                else {
 756                deleted_file:
 757                        result_size = 0;
 758                        elem->mode = 0;
 759                        result = xcalloc(1, 1);
 760                }
 761
 762                if (0 <= fd)
 763                        close(fd);
 764        }
 765
 766        for (cnt = 0, cp = result; cp < result + result_size; cp++) {
 767                if (*cp == '\n')
 768                        cnt++;
 769        }
 770        if (result_size && result[result_size-1] != '\n')
 771                cnt++; /* incomplete line */
 772
 773        sline = xcalloc(cnt+2, sizeof(*sline));
 774        sline[0].bol = result;
 775        for (lno = 0; lno <= cnt + 1; lno++) {
 776                sline[lno].lost_tail = &sline[lno].lost_head;
 777                sline[lno].flag = 0;
 778        }
 779        for (lno = 0, cp = result; cp < result + result_size; cp++) {
 780                if (*cp == '\n') {
 781                        sline[lno].len = cp - sline[lno].bol;
 782                        lno++;
 783                        if (lno < cnt)
 784                                sline[lno].bol = cp + 1;
 785                }
 786        }
 787        if (result_size && result[result_size-1] != '\n')
 788                sline[cnt-1].len = result_size - (sline[cnt-1].bol - result);
 789
 790        result_file.ptr = result;
 791        result_file.size = result_size;
 792
 793        /* Even p_lno[cnt+1] is valid -- that is for the end line number
 794         * for deletion hunk at the end.
 795         */
 796        sline[0].p_lno = xcalloc((cnt+2) * num_parent, sizeof(unsigned long));
 797        for (lno = 0; lno <= cnt; lno++)
 798                sline[lno+1].p_lno = sline[lno].p_lno + num_parent;
 799
 800        for (i = 0; i < num_parent; i++) {
 801                int j;
 802                for (j = 0; j < i; j++) {
 803                        if (!hashcmp(elem->parent[i].sha1,
 804                                     elem->parent[j].sha1)) {
 805                                reuse_combine_diff(sline, cnt, i, j);
 806                                break;
 807                        }
 808                }
 809                if (i <= j)
 810                        combine_diff(elem->parent[i].sha1, &result_file, sline,
 811                                     cnt, i, num_parent);
 812                if (elem->parent[i].mode != elem->mode)
 813                        mode_differs = 1;
 814        }
 815
 816        show_hunks = make_hunks(sline, cnt, num_parent, dense);
 817
 818        if (show_hunks || mode_differs || working_tree_file) {
 819                const char *abb;
 820                int use_color = DIFF_OPT_TST(opt, COLOR_DIFF);
 821                const char *c_meta = diff_get_color(use_color, DIFF_METAINFO);
 822                const char *c_reset = diff_get_color(use_color, DIFF_RESET);
 823                int added = 0;
 824                int deleted = 0;
 825
 826                if (rev->loginfo && !rev->no_commit_id)
 827                        show_log(rev);
 828                dump_quoted_path(dense ? "diff --cc " : "diff --combined ",
 829                                 "", elem->path, c_meta, c_reset);
 830                printf("%sindex ", c_meta);
 831                for (i = 0; i < num_parent; i++) {
 832                        abb = find_unique_abbrev(elem->parent[i].sha1,
 833                                                 abbrev);
 834                        printf("%s%s", i ? "," : "", abb);
 835                }
 836                abb = find_unique_abbrev(elem->sha1, abbrev);
 837                printf("..%s%s\n", abb, c_reset);
 838
 839                if (mode_differs) {
 840                        deleted = !elem->mode;
 841
 842                        /* We say it was added if nobody had it */
 843                        added = !deleted;
 844                        for (i = 0; added && i < num_parent; i++)
 845                                if (elem->parent[i].status !=
 846                                    DIFF_STATUS_ADDED)
 847                                        added = 0;
 848                        if (added)
 849                                printf("%snew file mode %06o",
 850                                       c_meta, elem->mode);
 851                        else {
 852                                if (deleted)
 853                                        printf("%sdeleted file ", c_meta);
 854                                printf("mode ");
 855                                for (i = 0; i < num_parent; i++) {
 856                                        printf("%s%06o", i ? "," : "",
 857                                               elem->parent[i].mode);
 858                                }
 859                                if (elem->mode)
 860                                        printf("..%06o", elem->mode);
 861                        }
 862                        printf("%s\n", c_reset);
 863                }
 864                if (added)
 865                        dump_quoted_path("--- ", "", "/dev/null",
 866                                         c_meta, c_reset);
 867                else
 868                        dump_quoted_path("--- ", a_prefix, elem->path,
 869                                         c_meta, c_reset);
 870                if (deleted)
 871                        dump_quoted_path("+++ ", "", "/dev/null",
 872                                         c_meta, c_reset);
 873                else
 874                        dump_quoted_path("+++ ", b_prefix, elem->path,
 875                                         c_meta, c_reset);
 876                dump_sline(sline, cnt, num_parent,
 877                           DIFF_OPT_TST(opt, COLOR_DIFF));
 878        }
 879        free(result);
 880
 881        for (lno = 0; lno < cnt; lno++) {
 882                if (sline[lno].lost_head) {
 883                        struct lline *ll = sline[lno].lost_head;
 884                        while (ll) {
 885                                struct lline *tmp = ll;
 886                                ll = ll->next;
 887                                free(tmp);
 888                        }
 889                }
 890        }
 891        free(sline[0].p_lno);
 892        free(sline);
 893}
 894
 895#define COLONS "::::::::::::::::::::::::::::::::"
 896
 897static void show_raw_diff(struct combine_diff_path *p, int num_parent, struct rev_info *rev)
 898{
 899        struct diff_options *opt = &rev->diffopt;
 900        int i, offset;
 901        const char *prefix;
 902        int line_termination, inter_name_termination;
 903
 904        line_termination = opt->line_termination;
 905        inter_name_termination = '\t';
 906        if (!line_termination)
 907                inter_name_termination = 0;
 908
 909        if (rev->loginfo && !rev->no_commit_id)
 910                show_log(rev);
 911
 912        if (opt->output_format & DIFF_FORMAT_RAW) {
 913                offset = strlen(COLONS) - num_parent;
 914                if (offset < 0)
 915                        offset = 0;
 916                prefix = COLONS + offset;
 917
 918                /* Show the modes */
 919                for (i = 0; i < num_parent; i++) {
 920                        printf("%s%06o", prefix, p->parent[i].mode);
 921                        prefix = " ";
 922                }
 923                printf("%s%06o", prefix, p->mode);
 924
 925                /* Show sha1's */
 926                for (i = 0; i < num_parent; i++)
 927                        printf(" %s", diff_unique_abbrev(p->parent[i].sha1,
 928                                                         opt->abbrev));
 929                printf(" %s ", diff_unique_abbrev(p->sha1, opt->abbrev));
 930        }
 931
 932        if (opt->output_format & (DIFF_FORMAT_RAW | DIFF_FORMAT_NAME_STATUS)) {
 933                for (i = 0; i < num_parent; i++)
 934                        putchar(p->parent[i].status);
 935                putchar(inter_name_termination);
 936        }
 937
 938        write_name_quoted(p->path, stdout, line_termination);
 939}
 940
 941void show_combined_diff(struct combine_diff_path *p,
 942                       int num_parent,
 943                       int dense,
 944                       struct rev_info *rev)
 945{
 946        struct diff_options *opt = &rev->diffopt;
 947        if (!p->len)
 948                return;
 949        if (opt->output_format & (DIFF_FORMAT_RAW |
 950                                  DIFF_FORMAT_NAME |
 951                                  DIFF_FORMAT_NAME_STATUS))
 952                show_raw_diff(p, num_parent, rev);
 953        else if (opt->output_format & DIFF_FORMAT_PATCH)
 954                show_patch_diff(p, num_parent, dense, rev);
 955}
 956
 957void diff_tree_combined(const unsigned char *sha1,
 958                        const unsigned char parent[][20],
 959                        int num_parent,
 960                        int dense,
 961                        struct rev_info *rev)
 962{
 963        struct diff_options *opt = &rev->diffopt;
 964        struct diff_options diffopts;
 965        struct combine_diff_path *p, *paths = NULL;
 966        int i, num_paths, needsep, show_log_first;
 967
 968        diffopts = *opt;
 969        diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
 970        DIFF_OPT_SET(&diffopts, RECURSIVE);
 971        DIFF_OPT_CLR(&diffopts, ALLOW_EXTERNAL);
 972
 973        show_log_first = !!rev->loginfo && !rev->no_commit_id;
 974        needsep = 0;
 975        /* find set of paths that everybody touches */
 976        for (i = 0; i < num_parent; i++) {
 977                /* show stat against the first parent even
 978                 * when doing combined diff.
 979                 */
 980                int stat_opt = (opt->output_format &
 981                                (DIFF_FORMAT_NUMSTAT|DIFF_FORMAT_DIFFSTAT));
 982                if (i == 0 && stat_opt)
 983                        diffopts.output_format = stat_opt;
 984                else
 985                        diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
 986                diff_tree_sha1(parent[i], sha1, "", &diffopts);
 987                diffcore_std(&diffopts);
 988                paths = intersect_paths(paths, i, num_parent);
 989
 990                if (show_log_first && i == 0) {
 991                        show_log(rev);
 992                        if (rev->verbose_header && opt->output_format)
 993                                putchar(opt->line_termination);
 994                }
 995                diff_flush(&diffopts);
 996        }
 997
 998        /* find out surviving paths */
 999        for (num_paths = 0, p = paths; p; p = p->next) {
1000                if (p->len)
1001                        num_paths++;
1002        }
1003        if (num_paths) {
1004                if (opt->output_format & (DIFF_FORMAT_RAW |
1005                                          DIFF_FORMAT_NAME |
1006                                          DIFF_FORMAT_NAME_STATUS)) {
1007                        for (p = paths; p; p = p->next) {
1008                                if (p->len)
1009                                        show_raw_diff(p, num_parent, rev);
1010                        }
1011                        needsep = 1;
1012                }
1013                else if (opt->output_format &
1014                         (DIFF_FORMAT_NUMSTAT|DIFF_FORMAT_DIFFSTAT))
1015                        needsep = 1;
1016                if (opt->output_format & DIFF_FORMAT_PATCH) {
1017                        if (needsep)
1018                                putchar(opt->line_termination);
1019                        for (p = paths; p; p = p->next) {
1020                                if (p->len)
1021                                        show_patch_diff(p, num_parent, dense,
1022                                                        rev);
1023                        }
1024                }
1025        }
1026
1027        /* Clean things up */
1028        while (paths) {
1029                struct combine_diff_path *tmp = paths;
1030                paths = paths->next;
1031                free(tmp);
1032        }
1033}
1034
1035void diff_tree_combined_merge(const unsigned char *sha1,
1036                             int dense, struct rev_info *rev)
1037{
1038        int num_parent;
1039        const unsigned char (*parent)[20];
1040        struct commit *commit = lookup_commit(sha1);
1041        struct commit_list *parents;
1042
1043        /* count parents */
1044        for (parents = commit->parents, num_parent = 0;
1045             parents;
1046             parents = parents->next, num_parent++)
1047                ; /* nothing */
1048
1049        parent = xmalloc(num_parent * sizeof(*parent));
1050        for (parents = commit->parents, num_parent = 0;
1051             parents;
1052             parents = parents->next, num_parent++)
1053                hashcpy((unsigned char*)(parent + num_parent),
1054                        parents->item->object.sha1);
1055        diff_tree_combined(sha1, parent, num_parent, dense, rev);
1056}