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