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 #include "graph.h"
  14
  15 /* bits #0-15 in revision.h */
  16
  17 #define COUNTED         (1u<<16)
  18
  19 static const char rev_list_usage[] =
  20 "git rev-list [OPTION] <commit-id>... [ -- paths... ]\n"
  21 "  limiting output:\n"
  22 "    --max-count=nr\n"
  23 "    --max-age=epoch\n"
  24 "    --min-age=epoch\n"
  25 "    --sparse\n"
  26 "    --no-merges\n"
  27 "    --remove-empty\n"
  28 "    --all\n"
  29 "    --branches\n"
  30 "    --tags\n"
  31 "    --remotes\n"
  32 "    --stdin\n"
  33 "    --quiet\n"
  34 "  ordering output:\n"
  35 "    --topo-order\n"
  36 "    --date-order\n"
  37 "    --reverse\n"
  38 "  formatting output:\n"
  39 "    --parents\n"
  40 "    --children\n"
  41 "    --objects | --objects-edge\n"
  42 "    --unpacked\n"
  43 "    --header | --pretty\n"
  44 "    --abbrev=nr | --no-abbrev\n"
  45 "    --abbrev-commit\n"
  46 "    --left-right\n"
  47 "  special purpose:\n"
  48 "    --bisect\n"
  49 "    --bisect-vars\n"
  50 "    --bisect-all"
  51 ;
  52
  53 static struct rev_info revs;
  54
  55 static int bisect_list;
  56 static int show_timestamp;
  57 static int hdr_termination;
  58 static const char *header_prefix;
  59
  60 static void finish_commit(struct commit *commit);
  61 static void show_commit(struct commit *commit)
  62 {
  63         graph_show_commit(revs.graph);
  64
  65         if (show_timestamp)
  66                 printf("%lu ", commit->date);
  67         if (header_prefix)
  68                 fputs(header_prefix, stdout);
  69
  70         if (!revs.graph) {
  71                 if (commit->object.flags & BOUNDARY)
  72                         putchar('-');
  73                 else if (commit->object.flags & UNINTERESTING)
  74                         putchar('^');
  75                 else if (revs.left_right) {
  76                         if (commit->object.flags & SYMMETRIC_LEFT)
  77                                 putchar('<');
  78                         else
  79                                 putchar('>');
  80                 }
  81         }
  82         if (revs.abbrev_commit && revs.abbrev)
  83                 fputs(find_unique_abbrev(commit->object.sha1, revs.abbrev),
  84                       stdout);
  85         else
  86                 fputs(sha1_to_hex(commit->object.sha1), stdout);
  87         if (revs.print_parents) {
  88                 struct commit_list *parents = commit->parents;
  89                 while (parents) {
  90                         printf(" %s", sha1_to_hex(parents->item->object.sha1));
  91                         parents = parents->next;
  92                 }
  93         }
  94         if (revs.children.name) {
  95                 struct commit_list *children;
  96
  97                 children = lookup_decoration(&revs.children, &commit->object);
  98                 while (children) {
  99                         printf(" %s", sha1_to_hex(children->item->object.sha1));
 100                         children = children->next;
 101                 }
 102         }
 103         show_decorations(&revs, commit);
 104         if (revs.commit_format == CMIT_FMT_ONELINE)
 105                 putchar(' ');
 106         else
 107                 putchar('\n');
 108
 109         if (revs.verbose_header && commit->buffer) {
 110                 struct strbuf buf = STRBUF_INIT;
 111                 pretty_print_commit(revs.commit_format, commit,
 112                                     &buf, revs.abbrev, NULL, NULL,
 113                                     revs.date_mode, 0);
 114                 if (revs.graph) {
 115                         if (buf.len) {
 116                                 if (revs.commit_format != CMIT_FMT_ONELINE)
 117                                         graph_show_oneline(revs.graph);
 118
 119                                 graph_show_commit_msg(revs.graph, &buf);
 120
 121                                 /*
 122                                  * Add a newline after the commit message.
 123                                  *
 124                                  * Usually, this newline produces a blank
 125                                  * padding line between entries, in which case
 126                                  * we need to add graph padding on this line.
 127                                  *
 128                                  * However, the commit message may not end in a
 129                                  * newline.  In this case the newline simply
 130                                  * ends the last line of the commit message,
 131                                  * and we don't need any graph output.  (This
 132                                  * always happens with CMIT_FMT_ONELINE, and it
 133                                  * happens with CMIT_FMT_USERFORMAT when the
 134                                  * format doesn't explicitly end in a newline.)
 135                                  */
 136                                 if (buf.len && buf.buf[buf.len - 1] == '\n')
 137                                         graph_show_padding(revs.graph);
 138                                 putchar('\n');
 139                         } else {
 140                                 /*
 141                                  * If the message buffer is empty, just show
 142                                  * the rest of the graph output for this
 143                                  * commit.
 144                                  */
 145                                 if (graph_show_remainder(revs.graph))
 146                                         putchar('\n');
 147                         }
 148                 } else {
 149                         if (buf.len)
 150                                 printf("%s%c", buf.buf, hdr_termination);
 151                 }
 152                 strbuf_release(&buf);
 153         } else {
 154                 if (graph_show_remainder(revs.graph))
 155                         putchar('\n');
 156         }
 157         maybe_flush_or_die(stdout, "stdout");
 158         finish_commit(commit);
 159 }
 160
 161 static void finish_commit(struct commit *commit)
 162 {
 163         if (commit->parents) {
 164                 free_commit_list(commit->parents);
 165                 commit->parents = NULL;
 166         }
 167         free(commit->buffer);
 168         commit->buffer = NULL;
 169 }
 170
 171 static void finish_object(struct object_array_entry *p)
 172 {
 173         if (p->item->type == OBJ_BLOB && !has_sha1_file(p->item->sha1))
 174                 die("missing blob object '%s'", sha1_to_hex(p->item->sha1));
 175 }
 176
 177 static void show_object(struct object_array_entry *p)
 178 {
 179         /* An object with name "foo\n0000000..." can be used to
 180          * confuse downstream "git pack-objects" very badly.
 181          */
 182         const char *ep = strchr(p->name, '\n');
 183
 184         finish_object(p);
 185         if (ep) {
 186                 printf("%s %.*s\n", sha1_to_hex(p->item->sha1),
 187                        (int) (ep - p->name),
 188                        p->name);
 189         }
 190         else
 191                 printf("%s %s\n", sha1_to_hex(p->item->sha1), p->name);
 192 }
 193
 194 static void show_edge(struct commit *commit)
 195 {
 196         printf("-%s\n", sha1_to_hex(commit->object.sha1));
 197 }
 198
 199 /*
 200  * This is a truly stupid algorithm, but it's only
 201  * used for bisection, and we just don't care enough.
 202  *
 203  * We care just barely enough to avoid recursing for
 204  * non-merge entries.
 205  */
 206 static int count_distance(struct commit_list *entry)
 207 {
 208         int nr = 0;
 209
 210         while (entry) {
 211                 struct commit *commit = entry->item;
 212                 struct commit_list *p;
 213
 214                 if (commit->object.flags & (UNINTERESTING | COUNTED))
 215                         break;
 216                 if (!(commit->object.flags & TREESAME))
 217                         nr++;
 218                 commit->object.flags |= COUNTED;
 219                 p = commit->parents;
 220                 entry = p;
 221                 if (p) {
 222                         p = p->next;
 223                         while (p) {
 224                                 nr += count_distance(p);
 225                                 p = p->next;
 226                         }
 227                 }
 228         }
 229
 230         return nr;
 231 }
 232
 233 static void clear_distance(struct commit_list *list)
 234 {
 235         while (list) {
 236                 struct commit *commit = list->item;
 237                 commit->object.flags &= ~COUNTED;
 238                 list = list->next;
 239         }
 240 }
 241
 242 #define DEBUG_BISECT 0
 243
 244 static inline int weight(struct commit_list *elem)
 245 {
 246         return *((int*)(elem->item->util));
 247 }
 248
 249 static inline void weight_set(struct commit_list *elem, int weight)
 250 {
 251         *((int*)(elem->item->util)) = weight;
 252 }
 253
 254 static int count_interesting_parents(struct commit *commit)
 255 {
 256         struct commit_list *p;
 257         int count;
 258
 259         for (count = 0, p = commit->parents; p; p = p->next) {
 260                 if (p->item->object.flags & UNINTERESTING)
 261                         continue;
 262                 count++;
 263         }
 264         return count;
 265 }
 266
 267 static inline int halfway(struct commit_list *p, int nr)
 268 {
 269         /*
 270          * Don't short-cut something we are not going to return!
 271          */
 272         if (p->item->object.flags & TREESAME)
 273                 return 0;
 274         if (DEBUG_BISECT)
 275                 return 0;
 276         /*
 277          * 2 and 3 are halfway of 5.
 278          * 3 is halfway of 6 but 2 and 4 are not.
 279          */
 280         switch (2 * weight(p) - nr) {
 281         case -1: case 0: case 1:
 282                 return 1;
 283         default:
 284                 return 0;
 285         }
 286 }
 287
 288 #if !DEBUG_BISECT
 289 #define show_list(a,b,c,d) do { ; } while (0)
 290 #else
 291 static void show_list(const char *debug, int counted, int nr,
 292                       struct commit_list *list)
 293 {
 294         struct commit_list *p;
 295
 296         fprintf(stderr, "%s (%d/%d)\n", debug, counted, nr);
 297
 298         for (p = list; p; p = p->next) {
 299                 struct commit_list *pp;
 300                 struct commit *commit = p->item;
 301                 unsigned flags = commit->object.flags;
 302                 enum object_type type;
 303                 unsigned long size;
 304                 char *buf = read_sha1_file(commit->object.sha1, &type, &size);
 305                 char *ep, *sp;
 306
 307                 fprintf(stderr, "%c%c%c ",
 308                         (flags & TREESAME) ? ' ' : 'T',
 309                         (flags & UNINTERESTING) ? 'U' : ' ',
 310                         (flags & COUNTED) ? 'C' : ' ');
 311                 if (commit->util)
 312                         fprintf(stderr, "%3d", weight(p));
 313                 else
 314                         fprintf(stderr, "---");
 315                 fprintf(stderr, " %.*s", 8, sha1_to_hex(commit->object.sha1));
 316                 for (pp = commit->parents; pp; pp = pp->next)
 317                         fprintf(stderr, " %.*s", 8,
 318                                 sha1_to_hex(pp->item->object.sha1));
 319
 320                 sp = strstr(buf, "\n\n");
 321                 if (sp) {
 322                         sp += 2;
 323                         for (ep = sp; *ep && *ep != '\n'; ep++)
 324                                 ;
 325                         fprintf(stderr, " %.*s", (int)(ep - sp), sp);
 326                 }
 327                 fprintf(stderr, "\n");
 328         }
 329 }
 330 #endif /* DEBUG_BISECT */
 331
 332 static struct commit_list *best_bisection(struct commit_list *list, int nr)
 333 {
 334         struct commit_list *p, *best;
 335         int best_distance = -1;
 336
 337         best = list;
 338         for (p = list; p; p = p->next) {
 339                 int distance;
 340                 unsigned flags = p->item->object.flags;
 341
 342                 if (flags & TREESAME)
 343                         continue;
 344                 distance = weight(p);
 345                 if (nr - distance < distance)
 346                         distance = nr - distance;
 347                 if (distance > best_distance) {
 348                         best = p;
 349                         best_distance = distance;
 350                 }
 351         }
 352
 353         return best;
 354 }
 355
 356 struct commit_dist {
 357         struct commit *commit;
 358         int distance;
 359 };
 360
 361 static int compare_commit_dist(const void *a_, const void *b_)
 362 {
 363         struct commit_dist *a, *b;
 364
 365         a = (struct commit_dist *)a_;
 366         b = (struct commit_dist *)b_;
 367         if (a->distance != b->distance)
 368                 return b->distance - a->distance; /* desc sort */
 369         return hashcmp(a->commit->object.sha1, b->commit->object.sha1);
 370 }
 371
 372 static struct commit_list *best_bisection_sorted(struct commit_list *list, int nr)
 373 {
 374         struct commit_list *p;
 375         struct commit_dist *array = xcalloc(nr, sizeof(*array));
 376         int cnt, i;
 377
 378         for (p = list, cnt = 0; p; p = p->next) {
 379                 int distance;
 380                 unsigned flags = p->item->object.flags;
 381
 382                 if (flags & TREESAME)
 383                         continue;
 384                 distance = weight(p);
 385                 if (nr - distance < distance)
 386                         distance = nr - distance;
 387                 array[cnt].commit = p->item;
 388                 array[cnt].distance = distance;
 389                 cnt++;
 390         }
 391         qsort(array, cnt, sizeof(*array), compare_commit_dist);
 392         for (p = list, i = 0; i < cnt; i++) {
 393                 struct name_decoration *r = xmalloc(sizeof(*r) + 100);
 394                 struct object *obj = &(array[i].commit->object);
 395
 396                 sprintf(r->name, "dist=%d", array[i].distance);
 397                 r->next = add_decoration(&name_decoration, obj, r);
 398                 p->item = array[i].commit;
 399                 p = p->next;
 400         }
 401         if (p)
 402                 p->next = NULL;
 403         free(array);
 404         return list;
 405 }
 406
 407 /*
 408  * zero or positive weight is the number of interesting commits it can
 409  * reach, including itself.  Especially, weight = 0 means it does not
 410  * reach any tree-changing commits (e.g. just above uninteresting one
 411  * but traversal is with pathspec).
 412  *
 413  * weight = -1 means it has one parent and its distance is yet to
 414  * be computed.
 415  *
 416  * weight = -2 means it has more than one parent and its distance is
 417  * unknown.  After running count_distance() first, they will get zero
 418  * or positive distance.
 419  */
 420 static struct commit_list *do_find_bisection(struct commit_list *list,
 421                                              int nr, int *weights,
 422                                              int find_all)
 423 {
 424         int n, counted;
 425         struct commit_list *p;
 426
 427         counted = 0;
 428
 429         for (n = 0, p = list; p; p = p->next) {
 430                 struct commit *commit = p->item;
 431                 unsigned flags = commit->object.flags;
 432
 433                 p->item->util = &weights[n++];
 434                 switch (count_interesting_parents(commit)) {
 435                 case 0:
 436                         if (!(flags & TREESAME)) {
 437                                 weight_set(p, 1);
 438                                 counted++;
 439                                 show_list("bisection 2 count one",
 440                                           counted, nr, list);
 441                         }
 442                         /*
 443                          * otherwise, it is known not to reach any
 444                          * tree-changing commit and gets weight 0.
 445                          */
 446                         break;
 447                 case 1:
 448                         weight_set(p, -1);
 449                         break;
 450                 default:
 451                         weight_set(p, -2);
 452                         break;
 453                 }
 454         }
 455
 456         show_list("bisection 2 initialize", counted, nr, list);
 457
 458         /*
 459          * If you have only one parent in the resulting set
 460          * then you can reach one commit more than that parent
 461          * can reach.  So we do not have to run the expensive
 462          * count_distance() for single strand of pearls.
 463          *
 464          * However, if you have more than one parents, you cannot
 465          * just add their distance and one for yourself, since
 466          * they usually reach the same ancestor and you would
 467          * end up counting them twice that way.
 468          *
 469          * So we will first count distance of merges the usual
 470          * way, and then fill the blanks using cheaper algorithm.
 471          */
 472         for (p = list; p; p = p->next) {
 473                 if (p->item->object.flags & UNINTERESTING)
 474                         continue;
 475                 if (weight(p) != -2)
 476                         continue;
 477                 weight_set(p, count_distance(p));
 478                 clear_distance(list);
 479
 480                 /* Does it happen to be at exactly half-way? */
 481                 if (!find_all && halfway(p, nr))
 482                         return p;
 483                 counted++;
 484         }
 485
 486         show_list("bisection 2 count_distance", counted, nr, list);
 487
 488         while (counted < nr) {
 489                 for (p = list; p; p = p->next) {
 490                         struct commit_list *q;
 491                         unsigned flags = p->item->object.flags;
 492
 493                         if (0 <= weight(p))
 494                                 continue;
 495                         for (q = p->item->parents; q; q = q->next) {
 496                                 if (q->item->object.flags & UNINTERESTING)
 497                                         continue;
 498                                 if (0 <= weight(q))
 499                                         break;
 500                         }
 501                         if (!q)
 502                                 continue;
 503
 504                         /*
 505                          * weight for p is unknown but q is known.
 506                          * add one for p itself if p is to be counted,
 507                          * otherwise inherit it from q directly.
 508                          */
 509                         if (!(flags & TREESAME)) {
 510                                 weight_set(p, weight(q)+1);
 511                                 counted++;
 512                                 show_list("bisection 2 count one",
 513                                           counted, nr, list);
 514                         }
 515                         else
 516                                 weight_set(p, weight(q));
 517
 518                         /* Does it happen to be at exactly half-way? */
 519                         if (!find_all && halfway(p, nr))
 520                                 return p;
 521                 }
 522         }
 523
 524         show_list("bisection 2 counted all", counted, nr, list);
 525
 526         if (!find_all)
 527                 return best_bisection(list, nr);
 528         else
 529                 return best_bisection_sorted(list, nr);
 530 }
 531
 532 static struct commit_list *find_bisection(struct commit_list *list,
 533                                           int *reaches, int *all,
 534                                           int find_all)
 535 {
 536         int nr, on_list;
 537         struct commit_list *p, *best, *next, *last;
 538         int *weights;
 539
 540         show_list("bisection 2 entry", 0, 0, list);
 541
 542         /*
 543          * Count the number of total and tree-changing items on the
 544          * list, while reversing the list.
 545          */
 546         for (nr = on_list = 0, last = NULL, p = list;
 547              p;
 548              p = next) {
 549                 unsigned flags = p->item->object.flags;
 550
 551                 next = p->next;
 552                 if (flags & UNINTERESTING)
 553                         continue;
 554                 p->next = last;
 555                 last = p;
 556                 if (!(flags & TREESAME))
 557                         nr++;
 558                 on_list++;
 559         }
 560         list = last;
 561         show_list("bisection 2 sorted", 0, nr, list);
 562
 563         *all = nr;
 564         weights = xcalloc(on_list, sizeof(*weights));
 565
 566         /* Do the real work of finding bisection commit. */
 567         best = do_find_bisection(list, nr, weights, find_all);
 568         if (best) {
 569                 if (!find_all)
 570                         best->next = NULL;
 571                 *reaches = weight(best);
 572         }
 573         free(weights);
 574         return best;
 575 }
 576
 577 static inline int log2i(int n)
 578 {
 579         int log2 = 0;
 580
 581         for (; n > 1; n >>= 1)
 582                 log2++;
 583
 584         return log2;
 585 }
 586
 587 static inline int exp2i(int n)
 588 {
 589         return 1 << n;
 590 }
 591
 592 /*
 593  * Estimate the number of bisect steps left (after the current step)
 594  *
 595  * For any x between 0 included and 2^n excluded, the probability for
 596  * n - 1 steps left looks like:
 597  *
 598  * P(2^n + x) == (2^n - x) / (2^n + x)
 599  *
 600  * and P(2^n + x) < 0.5 means 2^n < 3x
 601  */
 602 static int estimate_bisect_steps(int all)
 603 {
 604         int n, x, e;
 605
 606         if (all < 3)
 607                 return 0;
 608
 609         n = log2i(all);
 610         e = exp2i(n);
 611         x = all - e;
 612
 613         return (e < 3 * x) ? n : n - 1;
 614 }
 615
 616 int cmd_rev_list(int argc, const char **argv, const char *prefix)
 617 {
 618         struct commit_list *list;
 619         int i;
 620         int read_from_stdin = 0;
 621         int bisect_show_vars = 0;
 622         int bisect_find_all = 0;
 623         int quiet = 0;
 624
 625         git_config(git_default_config, NULL);
 626         init_revisions(&revs, prefix);
 627         revs.abbrev = 0;
 628         revs.commit_format = CMIT_FMT_UNSPECIFIED;
 629         argc = setup_revisions(argc, argv, &revs, NULL);
 630
 631         quiet = DIFF_OPT_TST(&revs.diffopt, QUIET);
 632         for (i = 1 ; i < argc; i++) {
 633                 const char *arg = argv[i];
 634
 635                 if (!strcmp(arg, "--header")) {
 636                         revs.verbose_header = 1;
 637                         continue;
 638                 }
 639                 if (!strcmp(arg, "--timestamp")) {
 640                         show_timestamp = 1;
 641                         continue;
 642                 }
 643                 if (!strcmp(arg, "--bisect")) {
 644                         bisect_list = 1;
 645                         continue;
 646                 }
 647                 if (!strcmp(arg, "--bisect-all")) {
 648                         bisect_list = 1;
 649                         bisect_find_all = 1;
 650                         revs.show_decorations = 1;
 651                         continue;
 652                 }
 653                 if (!strcmp(arg, "--bisect-vars")) {
 654                         bisect_list = 1;
 655                         bisect_show_vars = 1;
 656                         continue;
 657                 }
 658                 if (!strcmp(arg, "--stdin")) {
 659                         if (read_from_stdin++)
 660                                 die("--stdin given twice?");
 661                         read_revisions_from_stdin(&revs);
 662                         continue;
 663                 }
 664                 usage(rev_list_usage);
 665
 666         }
 667         if (revs.commit_format != CMIT_FMT_UNSPECIFIED) {
 668                 /* The command line has a --pretty  */
 669                 hdr_termination = '\n';
 670                 if (revs.commit_format == CMIT_FMT_ONELINE)
 671                         header_prefix = "";
 672                 else
 673                         header_prefix = "commit ";
 674         }
 675         else if (revs.verbose_header)
 676                 /* Only --header was specified */
 677                 revs.commit_format = CMIT_FMT_RAW;
 678
 679         list = revs.commits;
 680
 681         if ((!list &&
 682              (!(revs.tag_objects||revs.tree_objects||revs.blob_objects) &&
 683               !revs.pending.nr)) ||
 684             revs.diff)
 685                 usage(rev_list_usage);
 686
 687         save_commit_buffer = revs.verbose_header ||
 688                 revs.grep_filter.pattern_list;
 689         if (bisect_list)
 690                 revs.limited = 1;
 691
 692         if (prepare_revision_walk(&revs))
 693                 die("revision walk setup failed");
 694         if (revs.tree_objects)
 695                 mark_edges_uninteresting(revs.commits, &revs, show_edge);
 696
 697         if (bisect_list) {
 698                 int reaches = reaches, all = all;
 699
 700                 revs.commits = find_bisection(revs.commits, &reaches, &all,
 701                                               bisect_find_all);
 702                 if (bisect_show_vars) {
 703                         int cnt;
 704                         char hex[41];
 705                         if (!revs.commits)
 706                                 return 1;
 707                         /*
 708                          * revs.commits can reach "reaches" commits among
 709                          * "all" commits.  If it is good, then there are
 710                          * (all-reaches) commits left to be bisected.
 711                          * On the other hand, if it is bad, then the set
 712                          * to bisect is "reaches".
 713                          * A bisect set of size N has (N-1) commits further
 714                          * to test, as we already know one bad one.
 715                          */
 716                         cnt = all - reaches;
 717                         if (cnt < reaches)
 718                                 cnt = reaches;
 719                         strcpy(hex, sha1_to_hex(revs.commits->item->object.sha1));
 720
 721                         if (bisect_find_all) {
 722                                 traverse_commit_list(&revs, show_commit, show_object);
 723                                 printf("------\n");
 724                         }
 725
 726                         printf("bisect_rev=%s\n"
 727                                "bisect_nr=%d\n"
 728                                "bisect_good=%d\n"
 729                                "bisect_bad=%d\n"
 730                                "bisect_all=%d\n"
 731                                "bisect_steps=%d\n",
 732                                hex,
 733                                cnt - 1,
 734                                all - reaches - 1,
 735                                reaches - 1,
 736                                all,
 737                                estimate_bisect_steps(all));
 738                         return 0;
 739                 }
 740         }
 741
 742         traverse_commit_list(&revs,
 743                 quiet ? finish_commit : show_commit,
 744                 quiet ? finish_object : show_object);
 745
 746         return 0;
 747 }