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
  13 /* bits #0-15 in revision.h */
  14
  15 #define COUNTED         (1u<<16)
  16
  17 static const char rev_list_usage[] =
  18 "git-rev-list [OPTION] <commit-id>... [ -- paths... ]\n"
  19 "  limiting output:\n"
  20 "    --max-count=nr\n"
  21 "    --max-age=epoch\n"
  22 "    --min-age=epoch\n"
  23 "    --sparse\n"
  24 "    --no-merges\n"
  25 "    --remove-empty\n"
  26 "    --all\n"
  27 "    --stdin\n"
  28 "  ordering output:\n"
  29 "    --topo-order\n"
  30 "    --date-order\n"
  31 "  formatting output:\n"
  32 "    --parents\n"
  33 "    --objects | --objects-edge\n"
  34 "    --unpacked\n"
  35 "    --header | --pretty\n"
  36 "    --abbrev=nr | --no-abbrev\n"
  37 "    --abbrev-commit\n"
  38 "    --left-right\n"
  39 "  special purpose:\n"
  40 "    --bisect\n"
  41 "    --bisect-vars"
  42 ;
  43
  44 static struct rev_info revs;
  45
  46 static int bisect_list;
  47 static int show_timestamp;
  48 static int hdr_termination;
  49 static const char *header_prefix;
  50
  51 static void show_commit(struct commit *commit)
  52 {
  53         if (show_timestamp)
  54                 printf("%lu ", commit->date);
  55         if (header_prefix)
  56                 fputs(header_prefix, stdout);
  57         if (commit->object.flags & BOUNDARY)
  58                 putchar('-');
  59         else if (revs.left_right) {
  60                 if (commit->object.flags & SYMMETRIC_LEFT)
  61                         putchar('<');
  62                 else
  63                         putchar('>');
  64         }
  65         if (revs.abbrev_commit && revs.abbrev)
  66                 fputs(find_unique_abbrev(commit->object.sha1, revs.abbrev),
  67                       stdout);
  68         else
  69                 fputs(sha1_to_hex(commit->object.sha1), stdout);
  70         if (revs.parents) {
  71                 struct commit_list *parents = commit->parents;
  72                 while (parents) {
  73                         struct object *o = &(parents->item->object);
  74                         parents = parents->next;
  75                         if (o->flags & TMP_MARK)
  76                                 continue;
  77                         printf(" %s", sha1_to_hex(o->sha1));
  78                         o->flags |= TMP_MARK;
  79                 }
  80                 /* TMP_MARK is a general purpose flag that can
  81                  * be used locally, but the user should clean
  82                  * things up after it is done with them.
  83                  */
  84                 for (parents = commit->parents;
  85                      parents;
  86                      parents = parents->next)
  87                         parents->item->object.flags &= ~TMP_MARK;
  88         }
  89         if (revs.commit_format == CMIT_FMT_ONELINE)
  90                 putchar(' ');
  91         else
  92                 putchar('\n');
  93
  94         if (revs.verbose_header) {
  95                 static char pretty_header[16384];
  96                 pretty_print_commit(revs.commit_format, commit, ~0,
  97                                     pretty_header, sizeof(pretty_header),
  98                                     revs.abbrev, NULL, NULL, revs.date_mode);
  99                 printf("%s%c", pretty_header, hdr_termination);
 100         }
 101         fflush(stdout);
 102         if (commit->parents) {
 103                 free_commit_list(commit->parents);
 104                 commit->parents = NULL;
 105         }
 106         free(commit->buffer);
 107         commit->buffer = NULL;
 108 }
 109
 110 static void show_object(struct object_array_entry *p)
 111 {
 112         /* An object with name "foo\n0000000..." can be used to
 113          * confuse downstream git-pack-objects very badly.
 114          */
 115         const char *ep = strchr(p->name, '\n');
 116
 117         if (p->item->type == OBJ_BLOB && !has_sha1_file(p->item->sha1))
 118                 die("missing blob object '%s'", sha1_to_hex(p->item->sha1));
 119
 120         if (ep) {
 121                 printf("%s %.*s\n", sha1_to_hex(p->item->sha1),
 122                        (int) (ep - p->name),
 123                        p->name);
 124         }
 125         else
 126                 printf("%s %s\n", sha1_to_hex(p->item->sha1), p->name);
 127 }
 128
 129 static void show_edge(struct commit *commit)
 130 {
 131         printf("-%s\n", sha1_to_hex(commit->object.sha1));
 132 }
 133
 134 /*
 135  * This is a truly stupid algorithm, but it's only
 136  * used for bisection, and we just don't care enough.
 137  *
 138  * We care just barely enough to avoid recursing for
 139  * non-merge entries.
 140  */
 141 static int count_distance(struct commit_list *entry)
 142 {
 143         int nr = 0;
 144
 145         while (entry) {
 146                 struct commit *commit = entry->item;
 147                 struct commit_list *p;
 148
 149                 if (commit->object.flags & (UNINTERESTING | COUNTED))
 150                         break;
 151                 if (!revs.prune_fn || (commit->object.flags & TREECHANGE))
 152                         nr++;
 153                 commit->object.flags |= COUNTED;
 154                 p = commit->parents;
 155                 entry = p;
 156                 if (p) {
 157                         p = p->next;
 158                         while (p) {
 159                                 nr += count_distance(p);
 160                                 p = p->next;
 161                         }
 162                 }
 163         }
 164
 165         return nr;
 166 }
 167
 168 static void clear_distance(struct commit_list *list)
 169 {
 170         while (list) {
 171                 struct commit *commit = list->item;
 172                 commit->object.flags &= ~COUNTED;
 173                 list = list->next;
 174         }
 175 }
 176
 177 #define DEBUG_BISECT 0
 178
 179 static inline int weight(struct commit_list *elem)
 180 {
 181         return *((int*)(elem->item->util));
 182 }
 183
 184 static inline void weight_set(struct commit_list *elem, int weight)
 185 {
 186         *((int*)(elem->item->util)) = weight;
 187 }
 188
 189 static int count_interesting_parents(struct commit *commit)
 190 {
 191         struct commit_list *p;
 192         int count;
 193
 194         for (count = 0, p = commit->parents; p; p = p->next) {
 195                 if (p->item->object.flags & UNINTERESTING)
 196                         continue;
 197                 count++;
 198         }
 199         return count;
 200 }
 201
 202 static inline int halfway(struct commit_list *p, int distance, int nr)
 203 {
 204         /*
 205          * Don't short-cut something we are not going to return!
 206          */
 207         if (revs.prune_fn && !(p->item->object.flags & TREECHANGE))
 208                 return 0;
 209         if (DEBUG_BISECT)
 210                 return 0;
 211         /*
 212          * 2 and 3 are halfway of 5.
 213          * 3 is halfway of 6 but 2 and 4 are not.
 214          */
 215         distance *= 2;
 216         switch (distance - nr) {
 217         case -1: case 0: case 1:
 218                 return 1;
 219         default:
 220                 return 0;
 221         }
 222 }
 223
 224 #if !DEBUG_BISECT
 225 #define show_list(a,b,c,d) do { ; } while (0)
 226 #else
 227 static void show_list(const char *debug, int counted, int nr,
 228                       struct commit_list *list)
 229 {
 230         struct commit_list *p;
 231
 232         fprintf(stderr, "%s (%d/%d)\n", debug, counted, nr);
 233
 234         for (p = list; p; p = p->next) {
 235                 struct commit_list *pp;
 236                 struct commit *commit = p->item;
 237                 unsigned flags = commit->object.flags;
 238                 enum object_type type;
 239                 unsigned long size;
 240                 char *buf = read_sha1_file(commit->object.sha1, &type, &size);
 241                 char *ep, *sp;
 242
 243                 fprintf(stderr, "%c%c%c ",
 244                         (flags & TREECHANGE) ? 'T' : ' ',
 245                         (flags & UNINTERESTING) ? 'U' : ' ',
 246                         (flags & COUNTED) ? 'C' : ' ');
 247                 if (commit->util)
 248                         fprintf(stderr, "%3d", weight(p));
 249                 else
 250                         fprintf(stderr, "---");
 251                 fprintf(stderr, " %.*s", 8, sha1_to_hex(commit->object.sha1));
 252                 for (pp = commit->parents; pp; pp = pp->next)
 253                         fprintf(stderr, " %.*s", 8,
 254                                 sha1_to_hex(pp->item->object.sha1));
 255
 256                 sp = strstr(buf, "\n\n");
 257                 if (sp) {
 258                         sp += 2;
 259                         for (ep = sp; *ep && *ep != '\n'; ep++)
 260                                 ;
 261                         fprintf(stderr, " %.*s", (int)(ep - sp), sp);
 262                 }
 263                 fprintf(stderr, "\n");
 264         }
 265 }
 266 #endif /* DEBUG_BISECT */
 267
 268 /*
 269  * zero or positive weight is the number of interesting commits it can
 270  * reach, including itself.  Especially, weight = 0 means it does not
 271  * reach any tree-changing commits (e.g. just above uninteresting one
 272  * but traversal is with pathspec).
 273  *
 274  * weight = -1 means it has one parent and its distance is yet to
 275  * be computed.
 276  *
 277  * weight = -2 means it has more than one parent and its distance is
 278  * unknown.  After running count_distance() first, they will get zero
 279  * or positive distance.
 280  */
 281
 282 static struct commit_list *find_bisection(struct commit_list *list,
 283                                           int *reaches, int *all)
 284 {
 285         int n, nr, on_list, counted, distance;
 286         struct commit_list *p, *best, *next, *last;
 287         int *weights;
 288
 289         show_list("bisection 2 entry", 0, 0, list);
 290
 291         /*
 292          * Count the number of total and tree-changing items on the
 293          * list, while reversing the list.
 294          */
 295         for (nr = on_list = 0, last = NULL, p = list;
 296              p;
 297              p = next) {
 298                 unsigned flags = p->item->object.flags;
 299
 300                 next = p->next;
 301                 if (flags & UNINTERESTING)
 302                         continue;
 303                 p->next = last;
 304                 last = p;
 305                 if (!revs.prune_fn || (flags & TREECHANGE))
 306                         nr++;
 307                 on_list++;
 308         }
 309         list = last;
 310         show_list("bisection 2 sorted", 0, nr, list);
 311
 312         *all = nr;
 313         weights = xcalloc(on_list, sizeof(int*));
 314         counted = 0;
 315
 316         for (n = 0, p = list; p; p = p->next) {
 317                 struct commit *commit = p->item;
 318                 unsigned flags = commit->object.flags;
 319
 320                 p->item->util = &weights[n++];
 321                 switch (count_interesting_parents(commit)) {
 322                 case 0:
 323                         if (!revs.prune_fn || (flags & TREECHANGE)) {
 324                                 weight_set(p, 1);
 325                                 counted++;
 326                                 show_list("bisection 2 count one",
 327                                           counted, nr, list);
 328                         }
 329                         /*
 330                          * otherwise, it is known not to reach any
 331                          * tree-changing commit and gets weight 0.
 332                          */
 333                         break;
 334                 case 1:
 335                         weight_set(p, -1);
 336                         break;
 337                 default:
 338                         weight_set(p, -2);
 339                         break;
 340                 }
 341         }
 342
 343         show_list("bisection 2 initialize", counted, nr, list);
 344
 345         /*
 346          * If you have only one parent in the resulting set
 347          * then you can reach one commit more than that parent
 348          * can reach.  So we do not have to run the expensive
 349          * count_distance() for single strand of pearls.
 350          *
 351          * However, if you have more than one parents, you cannot
 352          * just add their distance and one for yourself, since
 353          * they usually reach the same ancestor and you would
 354          * end up counting them twice that way.
 355          *
 356          * So we will first count distance of merges the usual
 357          * way, and then fill the blanks using cheaper algorithm.
 358          */
 359         for (p = list; p; p = p->next) {
 360                 if (p->item->object.flags & UNINTERESTING)
 361                         continue;
 362                 n = weight(p);
 363                 if (n != -2)
 364                         continue;
 365                 distance = count_distance(p);
 366                 clear_distance(list);
 367                 weight_set(p, distance);
 368
 369                 /* Does it happen to be at exactly half-way? */
 370                 if (halfway(p, distance, nr)) {
 371                         p->next = NULL;
 372                         *reaches = distance;
 373                         free(weights);
 374                         return p;
 375                 }
 376                 counted++;
 377         }
 378
 379         show_list("bisection 2 count_distance", counted, nr, list);
 380
 381         while (counted < nr) {
 382                 for (p = list; p; p = p->next) {
 383                         struct commit_list *q;
 384                         unsigned flags = p->item->object.flags;
 385
 386                         if (0 <= weight(p))
 387                                 continue;
 388                         for (q = p->item->parents; q; q = q->next) {
 389                                 if (q->item->object.flags & UNINTERESTING)
 390                                         continue;
 391                                 if (0 <= weight(q))
 392                                         break;
 393                         }
 394                         if (!q)
 395                                 continue;
 396
 397                         /*
 398                          * weight for p is unknown but q is known.
 399                          * add one for p itself if p is to be counted,
 400                          * otherwise inherit it from q directly.
 401                          */
 402                         if (!revs.prune_fn || (flags & TREECHANGE)) {
 403                                 weight_set(p, weight(q)+1);
 404                                 counted++;
 405                                 show_list("bisection 2 count one",
 406                                           counted, nr, list);
 407                         }
 408                         else
 409                                 weight_set(p, weight(q));
 410
 411                         /* Does it happen to be at exactly half-way? */
 412                         distance = weight(p);
 413                         if (halfway(p, distance, nr)) {
 414                                 p->next = NULL;
 415                                 *reaches = distance;
 416                                 free(weights);
 417                                 return p;
 418                         }
 419                 }
 420         }
 421
 422         show_list("bisection 2 counted all", counted, nr, list);
 423
 424         /* Then find the best one */
 425         counted = -1;
 426         best = list;
 427         for (p = list; p; p = p->next) {
 428                 unsigned flags = p->item->object.flags;
 429
 430                 if (revs.prune_fn && !(flags & TREECHANGE))
 431                         continue;
 432                 distance = weight(p);
 433                 if (nr - distance < distance)
 434                         distance = nr - distance;
 435                 if (distance > counted) {
 436                         best = p;
 437                         counted = distance;
 438                         *reaches = weight(p);
 439                 }
 440         }
 441         if (best)
 442                 best->next = NULL;
 443         free(weights);
 444         return best;
 445 }
 446
 447 static void read_revisions_from_stdin(struct rev_info *revs)
 448 {
 449         char line[1000];
 450
 451         while (fgets(line, sizeof(line), stdin) != NULL) {
 452                 int len = strlen(line);
 453                 if (line[len - 1] == '\n')
 454                         line[--len] = 0;
 455                 if (!len)
 456                         break;
 457                 if (line[0] == '-')
 458                         die("options not supported in --stdin mode");
 459                 if (handle_revision_arg(line, revs, 0, 1))
 460                         die("bad revision '%s'", line);
 461         }
 462 }
 463
 464 int cmd_rev_list(int argc, const char **argv, const char *prefix)
 465 {
 466         struct commit_list *list;
 467         int i;
 468         int read_from_stdin = 0;
 469         int bisect_show_vars = 0;
 470
 471         git_config(git_default_config);
 472         init_revisions(&revs, prefix);
 473         revs.abbrev = 0;
 474         revs.commit_format = CMIT_FMT_UNSPECIFIED;
 475         argc = setup_revisions(argc, argv, &revs, NULL);
 476
 477         for (i = 1 ; i < argc; i++) {
 478                 const char *arg = argv[i];
 479
 480                 if (!strcmp(arg, "--header")) {
 481                         revs.verbose_header = 1;
 482                         continue;
 483                 }
 484                 if (!strcmp(arg, "--timestamp")) {
 485                         show_timestamp = 1;
 486                         continue;
 487                 }
 488                 if (!strcmp(arg, "--bisect")) {
 489                         bisect_list = 1;
 490                         continue;
 491                 }
 492                 if (!strcmp(arg, "--bisect-vars")) {
 493                         bisect_list = 1;
 494                         bisect_show_vars = 1;
 495                         continue;
 496                 }
 497                 if (!strcmp(arg, "--stdin")) {
 498                         if (read_from_stdin++)
 499                                 die("--stdin given twice?");
 500                         read_revisions_from_stdin(&revs);
 501                         continue;
 502                 }
 503                 usage(rev_list_usage);
 504
 505         }
 506         if (revs.commit_format != CMIT_FMT_UNSPECIFIED) {
 507                 /* The command line has a --pretty  */
 508                 hdr_termination = '\n';
 509                 if (revs.commit_format == CMIT_FMT_ONELINE)
 510                         header_prefix = "";
 511                 else
 512                         header_prefix = "commit ";
 513         }
 514         else if (revs.verbose_header)
 515                 /* Only --header was specified */
 516                 revs.commit_format = CMIT_FMT_RAW;
 517
 518         list = revs.commits;
 519
 520         if ((!list &&
 521              (!(revs.tag_objects||revs.tree_objects||revs.blob_objects) &&
 522               !revs.pending.nr)) ||
 523             revs.diff)
 524                 usage(rev_list_usage);
 525
 526         save_commit_buffer = revs.verbose_header || revs.grep_filter;
 527         track_object_refs = 0;
 528         if (bisect_list)
 529                 revs.limited = 1;
 530
 531         prepare_revision_walk(&revs);
 532         if (revs.tree_objects)
 533                 mark_edges_uninteresting(revs.commits, &revs, show_edge);
 534
 535         if (bisect_list) {
 536                 int reaches = reaches, all = all;
 537
 538                 revs.commits = find_bisection(revs.commits, &reaches, &all);
 539                 if (bisect_show_vars) {
 540                         int cnt;
 541                         if (!revs.commits)
 542                                 return 1;
 543                         /*
 544                          * revs.commits can reach "reaches" commits among
 545                          * "all" commits.  If it is good, then there are
 546                          * (all-reaches) commits left to be bisected.
 547                          * On the other hand, if it is bad, then the set
 548                          * to bisect is "reaches".
 549                          * A bisect set of size N has (N-1) commits further
 550                          * to test, as we already know one bad one.
 551                          */
 552                         cnt = all-reaches;
 553                         if (cnt < reaches)
 554                                 cnt = reaches;
 555                         printf("bisect_rev=%s\n"
 556                                "bisect_nr=%d\n"
 557                                "bisect_good=%d\n"
 558                                "bisect_bad=%d\n"
 559                                "bisect_all=%d\n",
 560                                sha1_to_hex(revs.commits->item->object.sha1),
 561                                cnt - 1,
 562                                all - reaches - 1,
 563                                reaches - 1,
 564                                all);
 565                         return 0;
 566                 }
 567         }
 568
 569         traverse_commit_list(&revs, show_commit, show_object);
 570
 571         return 0;
 572 }