builtin-rev-list.c

   1 #include "cache.h"
   2 #include "refs.h"
   3 #include "tag.h"
   4 #include "commit.h"
   5 #include "tree.h"
   6 #include "blob.h"
   7 #include "tree-walk.h"
   8 #include "diff.h"
   9 #include "revision.h"
  10 #include "list-objects.h"
  11 #include "builtin.h"
  12 #include "log-tree.h"
  13
  14 /* bits #0-15 in revision.h */
  15
  16 #define COUNTED         (1u<<16)
  17
  18 static const char rev_list_usage[] =
  19 "git-rev-list [OPTION] <commit-id>... [ -- paths... ]\n"
  20 "  limiting output:\n"
  21 "    --max-count=nr\n"
  22 "    --max-age=epoch\n"
  23 "    --min-age=epoch\n"
  24 "    --sparse\n"
  25 "    --no-merges\n"
  26 "    --remove-empty\n"
  27 "    --all\n"
  28 "    --stdin\n"
  29 "    --quiet\n"
  30 "  ordering output:\n"
  31 "    --topo-order\n"
  32 "    --date-order\n"
  33 "  formatting output:\n"
  34 "    --parents\n"
  35 "    --objects | --objects-edge\n"
  36 "    --unpacked\n"
  37 "    --header | --pretty\n"
  38 "    --abbrev=nr | --no-abbrev\n"
  39 "    --abbrev-commit\n"
  40 "    --left-right\n"
  41 "  special purpose:\n"
  42 "    --bisect\n"
  43 "    --bisect-vars\n"
  44 "    --bisect-all"
  45 ;
  46
  47 static struct rev_info revs;
  48
  49 static int bisect_list;
  50 static int show_timestamp;
  51 static int hdr_termination;
  52 static const char *header_prefix;
  53
  54 static void finish_commit(struct commit *commit);
  55 static void show_commit(struct commit *commit)
  56 {
  57         if (show_timestamp)
  58                 printf("%lu ", commit->date);
  59         if (header_prefix)
  60                 fputs(header_prefix, stdout);
  61         if (commit->object.flags & BOUNDARY)
  62                 putchar('-');
  63         else if (revs.left_right) {
  64                 if (commit->object.flags & SYMMETRIC_LEFT)
  65                         putchar('<');
  66                 else
  67                         putchar('>');
  68         }
  69         if (revs.abbrev_commit && revs.abbrev)
  70                 fputs(find_unique_abbrev(commit->object.sha1, revs.abbrev),
  71                       stdout);
  72         else
  73                 fputs(sha1_to_hex(commit->object.sha1), stdout);
  74         if (revs.parents) {
  75                 struct commit_list *parents = commit->parents;
  76                 while (parents) {
  77                         printf(" %s", sha1_to_hex(parents->item->object.sha1));
  78                         parents = parents->next;
  79                 }
  80         }
  81         show_decorations(commit);
  82         if (revs.commit_format == CMIT_FMT_ONELINE)
  83                 putchar(' ');
  84         else
  85                 putchar('\n');
  86
  87         if (revs.verbose_header) {
  88                 struct strbuf buf;
  89                 strbuf_init(&buf, 0);
  90                 pretty_print_commit(revs.commit_format, commit,
  91                                     &buf, revs.abbrev, NULL, NULL,
  92                                     revs.date_mode, 0);
  93                 if (buf.len)
  94                         printf("%s%c", buf.buf, hdr_termination);
  95                 strbuf_release(&buf);
  96         }
  97         maybe_flush_or_die(stdout, "stdout");
  98         finish_commit(commit);
  99 }
 100
 101 static void finish_commit(struct commit *commit)
 102 {
 103         if (commit->parents) {
 104                 free_commit_list(commit->parents);
 105                 commit->parents = NULL;
 106         }
 107         free(commit->buffer);
 108         commit->buffer = NULL;
 109 }
 110
 111 static void finish_object(struct object_array_entry *p)
 112 {
 113         if (p->item->type == OBJ_BLOB && !has_sha1_file(p->item->sha1))
 114                 die("missing blob object '%s'", sha1_to_hex(p->item->sha1));
 115 }
 116
 117 static void show_object(struct object_array_entry *p)
 118 {
 119         /* An object with name "foo\n0000000..." can be used to
 120          * confuse downstream git-pack-objects very badly.
 121          */
 122         const char *ep = strchr(p->name, '\n');
 123
 124         finish_object(p);
 125         if (ep) {
 126                 printf("%s %.*s\n", sha1_to_hex(p->item->sha1),
 127                        (int) (ep - p->name),
 128                        p->name);
 129         }
 130         else
 131                 printf("%s %s\n", sha1_to_hex(p->item->sha1), p->name);
 132 }
 133
 134 static void show_edge(struct commit *commit)
 135 {
 136         printf("-%s\n", sha1_to_hex(commit->object.sha1));
 137 }
 138
 139 /*
 140  * This is a truly stupid algorithm, but it's only
 141  * used for bisection, and we just don't care enough.
 142  *
 143  * We care just barely enough to avoid recursing for
 144  * non-merge entries.
 145  */
 146 static int count_distance(struct commit_list *entry)
 147 {
 148         int nr = 0;
 149
 150         while (entry) {
 151                 struct commit *commit = entry->item;
 152                 struct commit_list *p;
 153
 154                 if (commit->object.flags & (UNINTERESTING | COUNTED))
 155                         break;
 156                 if (!(commit->object.flags & TREESAME))
 157                         nr++;
 158                 commit->object.flags |= COUNTED;
 159                 p = commit->parents;
 160                 entry = p;
 161                 if (p) {
 162                         p = p->next;
 163                         while (p) {
 164                                 nr += count_distance(p);
 165                                 p = p->next;
 166                         }
 167                 }
 168         }
 169
 170         return nr;
 171 }
 172
 173 static void clear_distance(struct commit_list *list)
 174 {
 175         while (list) {
 176                 struct commit *commit = list->item;
 177                 commit->object.flags &= ~COUNTED;
 178                 list = list->next;
 179         }
 180 }
 181
 182 #define DEBUG_BISECT 0
 183
 184 static inline int weight(struct commit_list *elem)
 185 {
 186         return *((int*)(elem->item->util));
 187 }
 188
 189 static inline void weight_set(struct commit_list *elem, int weight)
 190 {
 191         *((int*)(elem->item->util)) = weight;
 192 }
 193
 194 static int count_interesting_parents(struct commit *commit)
 195 {
 196         struct commit_list *p;
 197         int count;
 198
 199         for (count = 0, p = commit->parents; p; p = p->next) {
 200                 if (p->item->object.flags & UNINTERESTING)
 201                         continue;
 202                 count++;
 203         }
 204         return count;
 205 }
 206
 207 static inline int halfway(struct commit_list *p, int nr)
 208 {
 209         /*
 210          * Don't short-cut something we are not going to return!
 211          */
 212         if (p->item->object.flags & TREESAME)
 213                 return 0;
 214         if (DEBUG_BISECT)
 215                 return 0;
 216         /*
 217          * 2 and 3 are halfway of 5.
 218          * 3 is halfway of 6 but 2 and 4 are not.
 219          */
 220         switch (2 * weight(p) - nr) {
 221         case -1: case 0: case 1:
 222                 return 1;
 223         default:
 224                 return 0;
 225         }
 226 }
 227
 228 #if !DEBUG_BISECT
 229 #define show_list(a,b,c,d) do { ; } while (0)
 230 #else
 231 static void show_list(const char *debug, int counted, int nr,
 232                       struct commit_list *list)
 233 {
 234         struct commit_list *p;
 235
 236         fprintf(stderr, "%s (%d/%d)\n", debug, counted, nr);
 237
 238         for (p = list; p; p = p->next) {
 239                 struct commit_list *pp;
 240                 struct commit *commit = p->item;
 241                 unsigned flags = commit->object.flags;
 242                 enum object_type type;
 243                 unsigned long size;
 244                 char *buf = read_sha1_file(commit->object.sha1, &type, &size);
 245                 char *ep, *sp;
 246
 247                 fprintf(stderr, "%c%c%c ",
 248                         (flags & TREESAME) ? ' ' : 'T',
 249                         (flags & UNINTERESTING) ? 'U' : ' ',
 250                         (flags & COUNTED) ? 'C' : ' ');
 251                 if (commit->util)
 252                         fprintf(stderr, "%3d", weight(p));
 253                 else
 254                         fprintf(stderr, "---");
 255                 fprintf(stderr, " %.*s", 8, sha1_to_hex(commit->object.sha1));
 256                 for (pp = commit->parents; pp; pp = pp->next)
 257                         fprintf(stderr, " %.*s", 8,
 258                                 sha1_to_hex(pp->item->object.sha1));
 259
 260                 sp = strstr(buf, "\n\n");
 261                 if (sp) {
 262                         sp += 2;
 263                         for (ep = sp; *ep && *ep != '\n'; ep++)
 264                                 ;
 265                         fprintf(stderr, " %.*s", (int)(ep - sp), sp);
 266                 }
 267                 fprintf(stderr, "\n");
 268         }
 269 }
 270 #endif /* DEBUG_BISECT */
 271
 272 static struct commit_list *best_bisection(struct commit_list *list, int nr)
 273 {
 274         struct commit_list *p, *best;
 275         int best_distance = -1;
 276
 277         best = list;
 278         for (p = list; p; p = p->next) {
 279                 int distance;
 280                 unsigned flags = p->item->object.flags;
 281
 282                 if (flags & TREESAME)
 283                         continue;
 284                 distance = weight(p);
 285                 if (nr - distance < distance)
 286                         distance = nr - distance;
 287                 if (distance > best_distance) {
 288                         best = p;
 289                         best_distance = distance;
 290                 }
 291         }
 292
 293         return best;
 294 }
 295
 296 struct commit_dist {
 297         struct commit *commit;
 298         int distance;
 299 };
 300
 301 static int compare_commit_dist(const void *a_, const void *b_)
 302 {
 303         struct commit_dist *a, *b;
 304
 305         a = (struct commit_dist *)a_;
 306         b = (struct commit_dist *)b_;
 307         if (a->distance != b->distance)
 308                 return b->distance - a->distance; /* desc sort */
 309         return hashcmp(a->commit->object.sha1, b->commit->object.sha1);
 310 }
 311
 312 static struct commit_list *best_bisection_sorted(struct commit_list *list, int nr)
 313 {
 314         struct commit_list *p;
 315         struct commit_dist *array = xcalloc(nr, sizeof(*array));
 316         int cnt, i;
 317
 318         for (p = list, cnt = 0; p; p = p->next) {
 319                 int distance;
 320                 unsigned flags = p->item->object.flags;
 321
 322                 if (flags & TREESAME)
 323                         continue;
 324                 distance = weight(p);
 325                 if (nr - distance < distance)
 326                         distance = nr - distance;
 327                 array[cnt].commit = p->item;
 328                 array[cnt].distance = distance;
 329                 cnt++;
 330         }
 331         qsort(array, cnt, sizeof(*array), compare_commit_dist);
 332         for (p = list, i = 0; i < cnt; i++) {
 333                 struct name_decoration *r = xmalloc(sizeof(*r) + 100);
 334                 struct object *obj = &(array[i].commit->object);
 335
 336                 sprintf(r->name, "dist=%d", array[i].distance);
 337                 r->next = add_decoration(&name_decoration, obj, r);
 338                 p->item = array[i].commit;
 339                 p = p->next;
 340         }
 341         if (p)
 342                 p->next = NULL;
 343         free(array);
 344         return list;
 345 }
 346
 347 /*
 348  * zero or positive weight is the number of interesting commits it can
 349  * reach, including itself.  Especially, weight = 0 means it does not
 350  * reach any tree-changing commits (e.g. just above uninteresting one
 351  * but traversal is with pathspec).
 352  *
 353  * weight = -1 means it has one parent and its distance is yet to
 354  * be computed.
 355  *
 356  * weight = -2 means it has more than one parent and its distance is
 357  * unknown.  After running count_distance() first, they will get zero
 358  * or positive distance.
 359  */
 360 static struct commit_list *do_find_bisection(struct commit_list *list,
 361                                              int nr, int *weights,
 362                                              int find_all)
 363 {
 364         int n, counted;
 365         struct commit_list *p;
 366
 367         counted = 0;
 368
 369         for (n = 0, p = list; p; p = p->next) {
 370                 struct commit *commit = p->item;
 371                 unsigned flags = commit->object.flags;
 372
 373                 p->item->util = &weights[n++];
 374                 switch (count_interesting_parents(commit)) {
 375                 case 0:
 376                         if (!(flags & TREESAME)) {
 377                                 weight_set(p, 1);
 378                                 counted++;
 379                                 show_list("bisection 2 count one",
 380                                           counted, nr, list);
 381                         }
 382                         /*
 383                          * otherwise, it is known not to reach any
 384                          * tree-changing commit and gets weight 0.
 385                          */
 386                         break;
 387                 case 1:
 388                         weight_set(p, -1);
 389                         break;
 390                 default:
 391                         weight_set(p, -2);
 392                         break;
 393                 }
 394         }
 395
 396         show_list("bisection 2 initialize", counted, nr, list);
 397
 398         /*
 399          * If you have only one parent in the resulting set
 400          * then you can reach one commit more than that parent
 401          * can reach.  So we do not have to run the expensive
 402          * count_distance() for single strand of pearls.
 403          *
 404          * However, if you have more than one parents, you cannot
 405          * just add their distance and one for yourself, since
 406          * they usually reach the same ancestor and you would
 407          * end up counting them twice that way.
 408          *
 409          * So we will first count distance of merges the usual
 410          * way, and then fill the blanks using cheaper algorithm.
 411          */
 412         for (p = list; p; p = p->next) {
 413                 if (p->item->object.flags & UNINTERESTING)
 414                         continue;
 415                 if (weight(p) != -2)
 416                         continue;
 417                 weight_set(p, count_distance(p));
 418                 clear_distance(list);
 419
 420                 /* Does it happen to be at exactly half-way? */
 421                 if (!find_all && halfway(p, nr))
 422                         return p;
 423                 counted++;
 424         }
 425
 426         show_list("bisection 2 count_distance", counted, nr, list);
 427
 428         while (counted < nr) {
 429                 for (p = list; p; p = p->next) {
 430                         struct commit_list *q;
 431                         unsigned flags = p->item->object.flags;
 432
 433                         if (0 <= weight(p))
 434                                 continue;
 435                         for (q = p->item->parents; q; q = q->next) {
 436                                 if (q->item->object.flags & UNINTERESTING)
 437                                         continue;
 438                                 if (0 <= weight(q))
 439                                         break;
 440                         }
 441                         if (!q)
 442                                 continue;
 443
 444                         /*
 445                          * weight for p is unknown but q is known.
 446                          * add one for p itself if p is to be counted,
 447                          * otherwise inherit it from q directly.
 448                          */
 449                         if (!(flags & TREESAME)) {
 450                                 weight_set(p, weight(q)+1);
 451                                 counted++;
 452                                 show_list("bisection 2 count one",
 453                                           counted, nr, list);
 454                         }
 455                         else
 456                                 weight_set(p, weight(q));
 457
 458                         /* Does it happen to be at exactly half-way? */
 459                         if (!find_all && halfway(p, nr))
 460                                 return p;
 461                 }
 462         }
 463
 464         show_list("bisection 2 counted all", counted, nr, list);
 465
 466         if (!find_all)
 467                 return best_bisection(list, nr);
 468         else
 469                 return best_bisection_sorted(list, nr);
 470 }
 471
 472 static struct commit_list *find_bisection(struct commit_list *list,
 473                                           int *reaches, int *all,
 474                                           int find_all)
 475 {
 476         int nr, on_list;
 477         struct commit_list *p, *best, *next, *last;
 478         int *weights;
 479
 480         show_list("bisection 2 entry", 0, 0, list);
 481
 482         /*
 483          * Count the number of total and tree-changing items on the
 484          * list, while reversing the list.
 485          */
 486         for (nr = on_list = 0, last = NULL, p = list;
 487              p;
 488              p = next) {
 489                 unsigned flags = p->item->object.flags;
 490
 491                 next = p->next;
 492                 if (flags & UNINTERESTING)
 493                         continue;
 494                 p->next = last;
 495                 last = p;
 496                 if (!(flags & TREESAME))
 497                         nr++;
 498                 on_list++;
 499         }
 500         list = last;
 501         show_list("bisection 2 sorted", 0, nr, list);
 502
 503         *all = nr;
 504         weights = xcalloc(on_list, sizeof(*weights));
 505
 506         /* Do the real work of finding bisection commit. */
 507         best = do_find_bisection(list, nr, weights, find_all);
 508         if (best) {
 509                 if (!find_all)
 510                         best->next = NULL;
 511                 *reaches = weight(best);
 512         }
 513         free(weights);
 514         return best;
 515 }
 516
 517 static void read_revisions_from_stdin(struct rev_info *revs)
 518 {
 519         char line[1000];
 520
 521         while (fgets(line, sizeof(line), stdin) != NULL) {
 522                 int len = strlen(line);
 523                 if (len && line[len - 1] == '\n')
 524                         line[--len] = 0;
 525                 if (!len)
 526                         break;
 527                 if (line[0] == '-')
 528                         die("options not supported in --stdin mode");
 529                 if (handle_revision_arg(line, revs, 0, 1))
 530                         die("bad revision '%s'", line);
 531         }
 532 }
 533
 534 int cmd_rev_list(int argc, const char **argv, const char *prefix)
 535 {
 536         struct commit_list *list;
 537         int i;
 538         int read_from_stdin = 0;
 539         int bisect_show_vars = 0;
 540         int bisect_find_all = 0;
 541         int quiet = 0;
 542
 543         git_config(git_default_config);
 544         init_revisions(&revs, prefix);
 545         revs.abbrev = 0;
 546         revs.commit_format = CMIT_FMT_UNSPECIFIED;
 547         argc = setup_revisions(argc, argv, &revs, NULL);
 548
 549         for (i = 1 ; i < argc; i++) {
 550                 const char *arg = argv[i];
 551
 552                 if (!strcmp(arg, "--header")) {
 553                         revs.verbose_header = 1;
 554                         continue;
 555                 }
 556                 if (!strcmp(arg, "--timestamp")) {
 557                         show_timestamp = 1;
 558                         continue;
 559                 }
 560                 if (!strcmp(arg, "--bisect")) {
 561                         bisect_list = 1;
 562                         continue;
 563                 }
 564                 if (!strcmp(arg, "--bisect-all")) {
 565                         bisect_list = 1;
 566                         bisect_find_all = 1;
 567                         continue;
 568                 }
 569                 if (!strcmp(arg, "--bisect-vars")) {
 570                         bisect_list = 1;
 571                         bisect_show_vars = 1;
 572                         continue;
 573                 }
 574                 if (!strcmp(arg, "--stdin")) {
 575                         if (read_from_stdin++)
 576                                 die("--stdin given twice?");
 577                         read_revisions_from_stdin(&revs);
 578                         continue;
 579                 }
 580                 if (!strcmp(arg, "--quiet")) {
 581                         quiet = 1;
 582                         continue;
 583                 }
 584                 usage(rev_list_usage);
 585
 586         }
 587         if (revs.commit_format != CMIT_FMT_UNSPECIFIED) {
 588                 /* The command line has a --pretty  */
 589                 hdr_termination = '\n';
 590                 if (revs.commit_format == CMIT_FMT_ONELINE)
 591                         header_prefix = "";
 592                 else
 593                         header_prefix = "commit ";
 594         }
 595         else if (revs.verbose_header)
 596                 /* Only --header was specified */
 597                 revs.commit_format = CMIT_FMT_RAW;
 598
 599         list = revs.commits;
 600
 601         if ((!list &&
 602              (!(revs.tag_objects||revs.tree_objects||revs.blob_objects) &&
 603               !revs.pending.nr)) ||
 604             revs.diff)
 605                 usage(rev_list_usage);
 606
 607         save_commit_buffer = revs.verbose_header || revs.grep_filter;
 608         track_object_refs = 0;
 609         if (bisect_list)
 610                 revs.limited = 1;
 611
 612         prepare_revision_walk(&revs);
 613         if (revs.tree_objects)
 614                 mark_edges_uninteresting(revs.commits, &revs, show_edge);
 615
 616         if (bisect_list) {
 617                 int reaches = reaches, all = all;
 618
 619                 revs.commits = find_bisection(revs.commits, &reaches, &all,
 620                                               bisect_find_all);
 621                 if (bisect_show_vars) {
 622                         int cnt;
 623                         char hex[41];
 624                         if (!revs.commits)
 625                                 return 1;
 626                         /*
 627                          * revs.commits can reach "reaches" commits among
 628                          * "all" commits.  If it is good, then there are
 629                          * (all-reaches) commits left to be bisected.
 630                          * On the other hand, if it is bad, then the set
 631                          * to bisect is "reaches".
 632                          * A bisect set of size N has (N-1) commits further
 633                          * to test, as we already know one bad one.
 634                          */
 635                         cnt = all - reaches;
 636                         if (cnt < reaches)
 637                                 cnt = reaches;
 638                         strcpy(hex, sha1_to_hex(revs.commits->item->object.sha1));
 639
 640                         if (bisect_find_all) {
 641                                 traverse_commit_list(&revs, show_commit, show_object);
 642                                 printf("------\n");
 643                         }
 644
 645                         printf("bisect_rev=%s\n"
 646                                "bisect_nr=%d\n"
 647                                "bisect_good=%d\n"
 648                                "bisect_bad=%d\n"
 649                                "bisect_all=%d\n",
 650                                hex,
 651                                cnt - 1,
 652                                all - reaches - 1,
 653                                reaches - 1,
 654                                all);
 655                         return 0;
 656                 }
 657         }
 658
 659         traverse_commit_list(&revs,
 660                 quiet ? finish_commit : show_commit,
 661                 quiet ? finish_object : show_object);
 662
 663         return 0;
 664 }