combine-diff.c

   1 #include "cache.h"
   2 #include "commit.h"
   3 #include "diff.h"
   4 #include "diffcore.h"
   5 #include "quote.h"
   6
   7 struct path_list {
   8         struct path_list *next;
   9         int len;
  10         char *path;
  11         unsigned char sha1[20];
  12         unsigned char parent_sha1[FLEX_ARRAY][20];
  13 };
  14
  15 static int uninteresting(struct diff_filepair *p)
  16 {
  17         if (diff_unmodified_pair(p))
  18                 return 1;
  19         if (!S_ISREG(p->one->mode) || !S_ISREG(p->two->mode))
  20                 return 1;
  21         return 0;
  22 }
  23
  24 static struct path_list *intersect_paths(struct path_list *curr,
  25                                          int n, int num_parent)
  26 {
  27         struct diff_queue_struct *q = &diff_queued_diff;
  28         struct path_list *p;
  29         int i;
  30
  31         if (!n) {
  32                 struct path_list *list = NULL, **tail = &list;
  33                 for (i = 0; i < q->nr; i++) {
  34                         int len;
  35                         const char *path;
  36                         if (uninteresting(q->queue[i]))
  37                                 continue;
  38                         path = q->queue[i]->two->path;
  39                         len = strlen(path);
  40
  41                         p = xmalloc(sizeof(*p) + len + 1 + num_parent * 20);
  42                         p->path = (char*) &(p->parent_sha1[num_parent][0]);
  43                         memcpy(p->path, path, len);
  44                         p->path[len] = 0;
  45                         p->len = len;
  46                         p->next = NULL;
  47                         memcpy(p->sha1, q->queue[i]->two->sha1, 20);
  48                         memcpy(p->parent_sha1[n], q->queue[i]->one->sha1, 20);
  49                         *tail = p;
  50                         tail = &p->next;
  51                 }
  52                 return list;
  53         }
  54
  55         for (p = curr; p; p = p->next) {
  56                 int found = 0;
  57                 if (!p->len)
  58                         continue;
  59                 for (i = 0; i < q->nr; i++) {
  60                         const char *path;
  61                         int len;
  62
  63                         if (uninteresting(q->queue[i]))
  64                                 continue;
  65                         path = q->queue[i]->two->path;
  66                         len = strlen(path);
  67                         if (len == p->len && !memcmp(path, p->path, len)) {
  68                                 found = 1;
  69                                 memcpy(p->parent_sha1[n],
  70                                        q->queue[i]->one->sha1, 20);
  71                                 break;
  72                         }
  73                 }
  74                 if (!found)
  75                         p->len = 0;
  76         }
  77         return curr;
  78 }
  79
  80 struct lline {
  81         struct lline *next;
  82         int len;
  83         unsigned long parent_map;
  84         char line[FLEX_ARRAY];
  85 };
  86
  87 struct sline {
  88         struct lline *lost_head, **lost_tail;
  89         char *bol;
  90         int len;
  91         unsigned long flag;
  92 };
  93
  94 static char *grab_blob(const unsigned char *sha1, unsigned long *size)
  95 {
  96         char *blob;
  97         char type[20];
  98         if (!memcmp(sha1, null_sha1, 20)) {
  99                 /* deleted blob */
 100                 *size = 0;
 101                 return xcalloc(1, 1);
 102         }
 103         blob = read_sha1_file(sha1, type, size);
 104         if (strcmp(type, "blob"))
 105                 die("object '%s' is not a blob!", sha1_to_hex(sha1));
 106         return blob;
 107 }
 108
 109 #define TMPPATHLEN 50
 110 #define MAXLINELEN 10240
 111
 112 static void write_to_temp_file(char *tmpfile, void *blob, unsigned long size)
 113 {
 114         int fd = git_mkstemp(tmpfile, TMPPATHLEN, ".diff_XXXXXX");
 115         if (fd < 0)
 116                 die("unable to create temp-file");
 117         if (write(fd, blob, size) != size)
 118                 die("unable to write temp-file");
 119         close(fd);
 120 }
 121
 122 static void write_temp_blob(char *tmpfile, const unsigned char *sha1)
 123 {
 124         unsigned long size;
 125         void *blob;
 126         blob = grab_blob(sha1, &size);
 127         write_to_temp_file(tmpfile, blob, size);
 128         free(blob);
 129 }
 130
 131 static int parse_num(char **cp_p, unsigned int *num_p)
 132 {
 133         char *cp = *cp_p;
 134         unsigned int num = 0;
 135         int read_some;
 136
 137         while ('0' <= *cp && *cp <= '9')
 138                 num = num * 10 + *cp++ - '0';
 139         if (!(read_some = cp - *cp_p))
 140                 return -1;
 141         *cp_p = cp;
 142         *num_p = num;
 143         return 0;
 144 }
 145
 146 static int parse_hunk_header(char *line, int len,
 147                              unsigned int *ob, unsigned int *on,
 148                              unsigned int *nb, unsigned int *nn)
 149 {
 150         char *cp;
 151         cp = line + 4;
 152         if (parse_num(&cp, ob)) {
 153         bad_line:
 154                 return error("malformed diff output: %s", line);
 155         }
 156         if (*cp == ',') {
 157                 cp++;
 158                 if (parse_num(&cp, on))
 159                         goto bad_line;
 160         }
 161         else
 162                 *on = 1;
 163         if (*cp++ != ' ' || *cp++ != '+')
 164                 goto bad_line;
 165         if (parse_num(&cp, nb))
 166                 goto bad_line;
 167         if (*cp == ',') {
 168                 cp++;
 169                 if (parse_num(&cp, nn))
 170                         goto bad_line;
 171         }
 172         else
 173                 *nn = 1;
 174         return -!!memcmp(cp, " @@", 3);
 175 }
 176
 177 static void append_lost(struct sline *sline, int n, const char *line)
 178 {
 179         struct lline *lline;
 180         int len = strlen(line);
 181         unsigned long this_mask = (1UL<<n);
 182         if (line[len-1] == '\n')
 183                 len--;
 184
 185         /* Check to see if we can squash things */
 186         if (sline->lost_head) {
 187                 struct lline *last_one = NULL;
 188                 /* We cannot squash it with earlier one */
 189                 for (lline = sline->lost_head;
 190                      lline;
 191                      lline = lline->next)
 192                         if (lline->parent_map & this_mask)
 193                                 last_one = lline;
 194                 lline = last_one ? last_one->next : sline->lost_head;
 195                 while (lline) {
 196                         if (lline->len == len &&
 197                             !memcmp(lline->line, line, len)) {
 198                                 lline->parent_map |= this_mask;
 199                                 return;
 200                         }
 201                         lline = lline->next;
 202                 }
 203         }
 204
 205         lline = xmalloc(sizeof(*lline) + len + 1);
 206         lline->len = len;
 207         lline->next = NULL;
 208         lline->parent_map = this_mask;
 209         memcpy(lline->line, line, len);
 210         lline->line[len] = 0;
 211         *sline->lost_tail = lline;
 212         sline->lost_tail = &lline->next;
 213 }
 214
 215 static void combine_diff(const unsigned char *parent, const char *ourtmp,
 216                          struct sline *sline, int cnt, int n)
 217 {
 218         FILE *in;
 219         char parent_tmp[TMPPATHLEN];
 220         char cmd[TMPPATHLEN * 2 + 1024];
 221         char line[MAXLINELEN];
 222         unsigned int lno, ob, on, nb, nn;
 223         unsigned long pmask = ~(1UL << n);
 224         struct sline *lost_bucket = NULL;
 225
 226         write_temp_blob(parent_tmp, parent);
 227         sprintf(cmd, "diff --unified=0 -La/x -Lb/x '%s' '%s'",
 228                 parent_tmp, ourtmp);
 229         in = popen(cmd, "r");
 230         if (!in)
 231                 return;
 232
 233         lno = 1;
 234         while (fgets(line, sizeof(line), in) != NULL) {
 235                 int len = strlen(line);
 236                 if (5 < len && !memcmp("@@ -", line, 4)) {
 237                         if (parse_hunk_header(line, len,
 238                                               &ob, &on, &nb, &nn))
 239                                 break;
 240                         lno = nb;
 241                         if (!nb) {
 242                                 /* @@ -1,2 +0,0 @@ to remove the
 243                                  * first two lines...
 244                                  */
 245                                 nb = 1;
 246                         }
 247                         lost_bucket = &sline[nb-1]; /* sline is 0 based */
 248                         continue;
 249                 }
 250                 if (!lost_bucket)
 251                         continue;
 252                 switch (line[0]) {
 253                 case '-':
 254                         append_lost(lost_bucket, n, line+1);
 255                         break;
 256                 case '+':
 257                         sline[lno-1].flag &= pmask;
 258                         lno++;
 259                         break;
 260                 }
 261         }
 262         fclose(in);
 263         unlink(parent_tmp);
 264 }
 265
 266 static unsigned long context = 3;
 267 static char combine_marker = '@';
 268
 269 static int interesting(struct sline *sline, unsigned long all_mask)
 270 {
 271         return ((sline->flag & all_mask) != all_mask || sline->lost_head);
 272 }
 273
 274 static unsigned long line_common_diff(struct sline *sline, unsigned long all_mask)
 275 {
 276         /*
 277          * Look at the line and see from which parents we have the
 278          * same difference.
 279          */
 280
 281         /* Lower bits of sline->flag records if the parent had this
 282          * line, so XOR with all_mask gives us on-bits for parents we
 283          * have differences with.
 284          */
 285         unsigned long common_adds = (sline->flag ^ all_mask) & all_mask;
 286         unsigned long common_removes = all_mask;
 287
 288         /* If all the parents have this line, that also counts as
 289          * having the same difference.
 290          */
 291         if (!common_adds)
 292                 common_adds = all_mask;
 293
 294         if (sline->lost_head) {
 295                 /* Lost head list records the lines removed from
 296                  * the parents, and parent_map records from which
 297                  * parent the line was removed.
 298                  */
 299                 struct lline *ll;
 300                 for (ll = sline->lost_head; ll; ll = ll->next) {
 301                         common_removes &= ll->parent_map;
 302                 }
 303         }
 304         return common_adds & common_removes;
 305 }
 306
 307 static unsigned long line_all_diff(struct sline *sline, unsigned long all_mask)
 308 {
 309         /*
 310          * Look at the line and see from which parents we have some difference.
 311          */
 312         unsigned long different = (sline->flag ^ all_mask) & all_mask;
 313         if (sline->lost_head) {
 314                 /* Lost head list records the lines removed from
 315                  * the parents, and parent_map records from which
 316                  * parent the line was removed.
 317                  */
 318                 struct lline *ll;
 319                 for (ll = sline->lost_head; ll; ll = ll->next) {
 320                         different |= ll->parent_map;
 321                 }
 322         }
 323         return different;
 324 }
 325
 326 static unsigned long adjust_hunk_tail(struct sline *sline,
 327                                       unsigned long all_mask,
 328                                       unsigned long hunk_begin,
 329                                       unsigned long i)
 330 {
 331         /* i points at the first uninteresting line.
 332          * If the last line of the hunk was interesting
 333          * only because it has some deletion, then
 334          * it is not all that interesting for the
 335          * purpose of giving trailing context lines.
 336          */
 337         if ((hunk_begin + 1 <= i) &&
 338             ((sline[i-1].flag & all_mask) == all_mask))
 339                 i--;
 340         return i;
 341 }
 342
 343 static unsigned long next_interesting(struct sline *sline,
 344                                       unsigned long mark,
 345                                       unsigned long i,
 346                                       unsigned long cnt,
 347                                       int uninteresting)
 348 {
 349         while (i < cnt)
 350                 if (uninteresting ?
 351                     !(sline[i].flag & mark) :
 352                     (sline[i].flag & mark))
 353                         return i;
 354                 else
 355                         i++;
 356         return cnt;
 357 }
 358
 359 static int give_context(struct sline *sline, unsigned long cnt, int num_parent)
 360 {
 361         unsigned long all_mask = (1UL<<num_parent) - 1;
 362         unsigned long mark = (1UL<<num_parent);
 363         unsigned long i;
 364
 365         i = next_interesting(sline, mark, 0, cnt, 0);
 366         if (cnt <= i)
 367                 return 0;
 368
 369         while (i < cnt) {
 370                 unsigned long j = (context < i) ? (i - context) : 0;
 371                 unsigned long k;
 372                 while (j < i)
 373                         sline[j++].flag |= mark;
 374
 375         again:
 376                 j = next_interesting(sline, mark, i, cnt, 1);
 377                 if (cnt <= j)
 378                         break; /* the rest are all interesting */
 379
 380                 /* lookahead context lines */
 381                 k = next_interesting(sline, mark, j, cnt, 0);
 382                 j = adjust_hunk_tail(sline, all_mask, i, j);
 383
 384                 if (k < j + context) {
 385                         /* k is interesting and [j,k) are not, but
 386                          * paint them interesting because the gap is small.
 387                          */
 388                         while (j < k)
 389                                 sline[j++].flag |= mark;
 390                         i = k;
 391                         goto again;
 392                 }
 393
 394                 /* j is the first uninteresting line and there is
 395                  * no overlap beyond it within context lines.
 396                  */
 397                 i = k;
 398                 k = (j + context < cnt) ? j + context : cnt;
 399                 while (j < k)
 400                         sline[j++].flag |= mark;
 401         }
 402         return 1;
 403 }
 404
 405 static int make_hunks(struct sline *sline, unsigned long cnt,
 406                        int num_parent, int dense)
 407 {
 408         unsigned long all_mask = (1UL<<num_parent) - 1;
 409         unsigned long mark = (1UL<<num_parent);
 410         unsigned long i;
 411         int has_interesting = 0;
 412
 413         for (i = 0; i < cnt; i++) {
 414                 if (interesting(&sline[i], all_mask))
 415                         sline[i].flag |= mark;
 416                 else
 417                         sline[i].flag &= ~mark;
 418         }
 419         if (!dense)
 420                 return give_context(sline, cnt, num_parent);
 421
 422         /* Look at each hunk, and if we have changes from only one
 423          * parent, or the changes are the same from all but one
 424          * parent, mark that uninteresting.
 425          */
 426         i = 0;
 427         while (i < cnt) {
 428                 unsigned long j, hunk_begin, hunk_end;
 429                 int same, diff;
 430                 unsigned long same_diff, all_diff;
 431                 while (i < cnt && !(sline[i].flag & mark))
 432                         i++;
 433                 if (cnt <= i)
 434                         break; /* No more interesting hunks */
 435                 hunk_begin = i;
 436                 for (j = i + 1; j < cnt; j++) {
 437                         if (!(sline[j].flag & mark)) {
 438                                 /* Look beyond the end to see if there
 439                                  * is an interesting line after this
 440                                  * hunk within context span.
 441                                  */
 442                                 unsigned long la; /* lookahead */
 443                                 int contin = 0;
 444                                 la = adjust_hunk_tail(sline, all_mask,
 445                                                      hunk_begin, j);
 446                                 la = (la + context < cnt) ?
 447                                         (la + context) : cnt;
 448                                 while (j <= --la) {
 449                                         if (sline[la].flag & mark) {
 450                                                 contin = 1;
 451                                                 break;
 452                                         }
 453                                 }
 454                                 if (!contin)
 455                                         break;
 456                                 j = la;
 457                         }
 458                 }
 459                 hunk_end = j;
 460
 461                 /* [i..hunk_end) are interesting.  Now does it have
 462                  * the same change with all but one parent?
 463                  */
 464                 same_diff = all_mask;
 465                 all_diff = 0;
 466                 for (j = i; j < hunk_end; j++) {
 467                         same_diff &= line_common_diff(sline + j, all_mask);
 468                         all_diff |= line_all_diff(sline + j, all_mask);
 469                 }
 470                 diff = same = 0;
 471                 for (j = 0; j < num_parent; j++) {
 472                         if (same_diff & (1UL<<j))
 473                                 same++;
 474                         if (all_diff & (1UL<<j))
 475                                 diff++;
 476                 }
 477                 if ((num_parent - 1 <= same) || (diff == 1)) {
 478                         /* This hunk is not that interesting after all */
 479                         for (j = hunk_begin; j < hunk_end; j++)
 480                                 sline[j].flag &= ~mark;
 481                 }
 482                 i = hunk_end;
 483         }
 484
 485         has_interesting = give_context(sline, cnt, num_parent);
 486         return has_interesting;
 487 }
 488
 489 static void dump_sline(struct sline *sline, int cnt, int num_parent)
 490 {
 491         unsigned long mark = (1UL<<num_parent);
 492         int i;
 493         int lno = 0;
 494
 495         while (1) {
 496                 struct sline *sl = &sline[lno];
 497                 int hunk_end;
 498                 while (lno < cnt && !(sline[lno].flag & mark))
 499                         lno++;
 500                 if (cnt <= lno)
 501                         break;
 502                 for (hunk_end = lno + 1; hunk_end < cnt; hunk_end++)
 503                         if (!(sline[hunk_end].flag & mark))
 504                                 break;
 505                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 506                 printf(" +%d,%d ", lno+1, hunk_end-lno);
 507                 for (i = 0; i <= num_parent; i++) putchar(combine_marker);
 508                 putchar('\n');
 509                 while (lno < hunk_end) {
 510                         struct lline *ll;
 511                         int j;
 512                         sl = &sline[lno++];
 513                         ll = sl->lost_head;
 514                         while (ll) {
 515                                 for (j = 0; j < num_parent; j++) {
 516                                         if (ll->parent_map & (1UL<<j))
 517                                                 putchar('-');
 518                                         else
 519                                                 putchar(' ');
 520                                 }
 521                                 puts(ll->line);
 522                                 ll = ll->next;
 523                         }
 524                         for (j = 0; j < num_parent; j++) {
 525                                 if ((1UL<<j) & sl->flag)
 526                                         putchar(' ');
 527                                 else
 528                                         putchar('+');
 529                         }
 530                         printf("%.*s\n", sl->len, sl->bol);
 531                 }
 532         }
 533 }
 534
 535 static int show_combined_diff(struct path_list *elem, int num_parent,
 536                               int dense, const char *header, int show_empty)
 537 {
 538         unsigned long size, cnt, lno;
 539         char *result, *cp, *ep;
 540         struct sline *sline; /* survived lines */
 541         int i, show_hunks, shown_header = 0;
 542         char ourtmp[TMPPATHLEN];
 543
 544         /* Read the result of merge first */
 545         result = grab_blob(elem->sha1, &size);
 546         write_to_temp_file(ourtmp, result, size);
 547
 548         for (cnt = 0, cp = result; cp - result < size; cp++) {
 549                 if (*cp == '\n')
 550                         cnt++;
 551         }
 552         if (result[size-1] != '\n')
 553                 cnt++; /* incomplete line */
 554
 555         sline = xcalloc(cnt, sizeof(*sline));
 556         ep = result;
 557         sline[0].bol = result;
 558         for (lno = 0, cp = result; cp - result < size; cp++) {
 559                 if (*cp == '\n') {
 560                         sline[lno].lost_tail = &sline[lno].lost_head;
 561                         sline[lno].len = cp - sline[lno].bol;
 562                         sline[lno].flag = (1UL<<num_parent) - 1;
 563                         lno++;
 564                         if (lno < cnt)
 565                                 sline[lno].bol = cp + 1;
 566                 }
 567         }
 568         if (result[size-1] != '\n') {
 569                 sline[cnt-1].lost_tail = &sline[cnt-1].lost_head;
 570                 sline[cnt-1].len = size - (sline[cnt-1].bol - result);
 571                 sline[cnt-1].flag = (1UL<<num_parent) - 1;
 572         }
 573
 574         for (i = 0; i < num_parent; i++)
 575                 combine_diff(elem->parent_sha1[i], ourtmp, sline, cnt, i);
 576
 577         show_hunks = make_hunks(sline, cnt, num_parent, dense);
 578
 579         if (header && (show_hunks || show_empty)) {
 580                 shown_header++;
 581                 puts(header);
 582         }
 583         if (show_hunks) {
 584                 printf("diff --%s ", dense ? "cc" : "combined");
 585                 if (quote_c_style(elem->path, NULL, NULL, 0))
 586                         quote_c_style(elem->path, NULL, stdout, 0);
 587                 else
 588                         printf("%s", elem->path);
 589                 putchar('\n');
 590                 dump_sline(sline, cnt, num_parent);
 591         }
 592         unlink(ourtmp);
 593         free(result);
 594
 595         for (i = 0; i < cnt; i++) {
 596                 if (sline[i].lost_head) {
 597                         struct lline *ll = sline[i].lost_head;
 598                         while (ll) {
 599                                 struct lline *tmp = ll;
 600                                 ll = ll->next;
 601                                 free(tmp);
 602                         }
 603                 }
 604         }
 605         free(sline);
 606         return shown_header;
 607 }
 608
 609 int diff_tree_combined_merge(const unsigned char *sha1,
 610                              const char *header,
 611                              int show_empty_merge, int dense)
 612 {
 613         struct commit *commit = lookup_commit(sha1);
 614         struct diff_options diffopts;
 615         struct commit_list *parents;
 616         struct path_list *p, *paths = NULL;
 617         int num_parent, i, num_paths;
 618
 619         diff_setup(&diffopts);
 620         diffopts.output_format = DIFF_FORMAT_NO_OUTPUT;
 621         diffopts.recursive = 1;
 622
 623         /* count parents */
 624         for (parents = commit->parents, num_parent = 0;
 625              parents;
 626              parents = parents->next, num_parent++)
 627                 ; /* nothing */
 628
 629         /* find set of paths that everybody touches */
 630         for (parents = commit->parents, i = 0;
 631              parents;
 632              parents = parents->next, i++) {
 633                 struct commit *parent = parents->item;
 634                 diff_tree_sha1(parent->object.sha1, commit->object.sha1, "",
 635                                &diffopts);
 636                 paths = intersect_paths(paths, i, num_parent);
 637                 diff_flush(&diffopts);
 638         }
 639
 640         /* find out surviving paths */
 641         for (num_paths = 0, p = paths; p; p = p->next) {
 642                 if (p->len)
 643                         num_paths++;
 644         }
 645         if (num_paths || show_empty_merge) {
 646                 for (p = paths; p; p = p->next) {
 647                         if (!p->len)
 648                                 continue;
 649                         if (show_combined_diff(p, num_parent, dense, header,
 650                                                show_empty_merge))
 651                                 header = NULL;
 652                 }
 653         }
 654
 655         /* Clean things up */
 656         while (paths) {
 657                 struct path_list *tmp = paths;
 658                 paths = paths->next;
 659                 free(tmp);
 660         }
 661         return 0;
 662 }