builtin/name-rev.c

   1 #include "builtin.h"
   2 #include "cache.h"
   3 #include "repository.h"
   4 #include "config.h"
   5 #include "commit.h"
   6 #include "tag.h"
   7 #include "refs.h"
   8 #include "parse-options.h"
   9 #include "prio-queue.h"
  10 #include "sha1-lookup.h"
  11 #include "commit-slab.h"
  12
  13 /*
  14  * One day.  See the 'name a rev shortly after epoch' test in t6120 when
  15  * changing this value
  16  */
  17 #define CUTOFF_DATE_SLOP 86400
  18
  19 struct rev_name {
  20         char *tip_name;
  21         timestamp_t taggerdate;
  22         int generation;
  23         int distance;
  24         int from_tag;
  25 };
  26
  27 define_commit_slab(commit_rev_name, struct rev_name);
  28
  29 static timestamp_t cutoff = TIME_MAX;
  30 static struct commit_rev_name rev_names;
  31
  32 /* How many generations are maximally preferred over _one_ merge traversal? */
  33 #define MERGE_TRAVERSAL_WEIGHT 65535
  34
  35 static int is_valid_rev_name(const struct rev_name *name)
  36 {
  37         return name && (name->generation || name->tip_name);
  38 }
  39
  40 static struct rev_name *get_commit_rev_name(const struct commit *commit)
  41 {
  42         struct rev_name *name = commit_rev_name_peek(&rev_names, commit);
  43
  44         return is_valid_rev_name(name) ? name : NULL;
  45 }
  46
  47 static int is_better_name(struct rev_name *name,
  48                           timestamp_t taggerdate,
  49                           int distance,
  50                           int from_tag)
  51 {
  52         /*
  53          * When comparing names based on tags, prefer names
  54          * based on the older tag, even if it is farther away.
  55          */
  56         if (from_tag && name->from_tag)
  57                 return (name->taggerdate > taggerdate ||
  58                         (name->taggerdate == taggerdate &&
  59                          name->distance > distance));
  60
  61         /*
  62          * We know that at least one of them is a non-tag at this point.
  63          * favor a tag over a non-tag.
  64          */
  65         if (name->from_tag != from_tag)
  66                 return from_tag;
  67
  68         /*
  69          * We are now looking at two non-tags.  Tiebreak to favor
  70          * shorter hops.
  71          */
  72         if (name->distance != distance)
  73                 return name->distance > distance;
  74
  75         /* ... or tiebreak to favor older date */
  76         if (name->taggerdate != taggerdate)
  77                 return name->taggerdate > taggerdate;
  78
  79         /* keep the current one if we cannot decide */
  80         return 0;
  81 }
  82
  83 static struct rev_name *create_or_update_name(struct commit *commit,
  84                                               timestamp_t taggerdate,
  85                                               int generation, int distance,
  86                                               int from_tag)
  87 {
  88         struct rev_name *name = commit_rev_name_at(&rev_names, commit);
  89
  90         if (is_valid_rev_name(name)) {
  91                 if (!is_better_name(name, taggerdate, distance, from_tag))
  92                         return NULL;
  93
  94                 /*
  95                  * This string might still be shared with ancestors
  96                  * (generation > 0).  We can release it here regardless,
  97                  * because the new name that has just won will be better
  98                  * for them as well, so name_rev() will replace these
  99                  * stale pointers when it processes the parents.
 100                  */
 101                 if (!name->generation)
 102                         free(name->tip_name);
 103         }
 104
 105         name->taggerdate = taggerdate;
 106         name->generation = generation;
 107         name->distance = distance;
 108         name->from_tag = from_tag;
 109
 110         return name;
 111 }
 112
 113 static char *get_parent_name(const struct rev_name *name, int parent_number)
 114 {
 115         struct strbuf sb = STRBUF_INIT;
 116         size_t len;
 117
 118         strip_suffix(name->tip_name, "^0", &len);
 119         if (name->generation > 0) {
 120                 strbuf_grow(&sb, len +
 121                             1 + decimal_width(name->generation) +
 122                             1 + decimal_width(parent_number));
 123                 strbuf_addf(&sb, "%.*s~%d^%d", (int)len, name->tip_name,
 124                             name->generation, parent_number);
 125         } else {
 126                 strbuf_grow(&sb, len +
 127                             1 + decimal_width(parent_number));
 128                 strbuf_addf(&sb, "%.*s^%d", (int)len, name->tip_name,
 129                             parent_number);
 130         }
 131         return strbuf_detach(&sb, NULL);
 132 }
 133
 134 static void name_rev(struct commit *start_commit,
 135                 const char *tip_name, timestamp_t taggerdate,
 136                 int from_tag, int deref)
 137 {
 138         struct prio_queue queue;
 139         struct commit *commit;
 140         struct commit **parents_to_queue = NULL;
 141         size_t parents_to_queue_nr, parents_to_queue_alloc = 0;
 142         struct rev_name *start_name;
 143
 144         parse_commit(start_commit);
 145         if (start_commit->date < cutoff)
 146                 return;
 147
 148         start_name = create_or_update_name(start_commit, taggerdate, 0, 0,
 149                                            from_tag);
 150         if (!start_name)
 151                 return;
 152         if (deref)
 153                 start_name->tip_name = xstrfmt("%s^0", tip_name);
 154         else
 155                 start_name->tip_name = xstrdup(tip_name);
 156
 157         memset(&queue, 0, sizeof(queue)); /* Use the prio_queue as LIFO */
 158         prio_queue_put(&queue, start_commit);
 159
 160         while ((commit = prio_queue_get(&queue))) {
 161                 struct rev_name *name = get_commit_rev_name(commit);
 162                 struct commit_list *parents;
 163                 int parent_number = 1;
 164
 165                 parents_to_queue_nr = 0;
 166
 167                 for (parents = commit->parents;
 168                                 parents;
 169                                 parents = parents->next, parent_number++) {
 170                         struct commit *parent = parents->item;
 171                         struct rev_name *parent_name;
 172                         int generation, distance;
 173
 174                         parse_commit(parent);
 175                         if (parent->date < cutoff)
 176                                 continue;
 177
 178                         if (parent_number > 1) {
 179                                 generation = 0;
 180                                 distance = name->distance + MERGE_TRAVERSAL_WEIGHT;
 181                         } else {
 182                                 generation = name->generation + 1;
 183                                 distance = name->distance + 1;
 184                         }
 185
 186                         parent_name = create_or_update_name(parent, taggerdate,
 187                                                             generation,
 188                                                             distance, from_tag);
 189                         if (parent_name) {
 190                                 if (parent_number > 1)
 191                                         parent_name->tip_name =
 192                                                 get_parent_name(name,
 193                                                                 parent_number);
 194                                 else
 195                                         parent_name->tip_name = name->tip_name;
 196                                 ALLOC_GROW(parents_to_queue,
 197                                            parents_to_queue_nr + 1,
 198                                            parents_to_queue_alloc);
 199                                 parents_to_queue[parents_to_queue_nr] = parent;
 200                                 parents_to_queue_nr++;
 201                         }
 202                 }
 203
 204                 /* The first parent must come out first from the prio_queue */
 205                 while (parents_to_queue_nr)
 206                         prio_queue_put(&queue,
 207                                        parents_to_queue[--parents_to_queue_nr]);
 208         }
 209
 210         clear_prio_queue(&queue);
 211         free(parents_to_queue);
 212 }
 213
 214 static int subpath_matches(const char *path, const char *filter)
 215 {
 216         const char *subpath = path;
 217
 218         while (subpath) {
 219                 if (!wildmatch(filter, subpath, 0))
 220                         return subpath - path;
 221                 subpath = strchr(subpath, '/');
 222                 if (subpath)
 223                         subpath++;
 224         }
 225         return -1;
 226 }
 227
 228 static const char *name_ref_abbrev(const char *refname, int shorten_unambiguous)
 229 {
 230         if (shorten_unambiguous)
 231                 refname = shorten_unambiguous_ref(refname, 0);
 232         else if (skip_prefix(refname, "refs/heads/", &refname))
 233                 ; /* refname already advanced */
 234         else
 235                 skip_prefix(refname, "refs/", &refname);
 236         return refname;
 237 }
 238
 239 struct name_ref_data {
 240         int tags_only;
 241         int name_only;
 242         struct string_list ref_filters;
 243         struct string_list exclude_filters;
 244 };
 245
 246 static struct tip_table {
 247         struct tip_table_entry {
 248                 struct object_id oid;
 249                 const char *refname;
 250                 struct commit *commit;
 251                 timestamp_t taggerdate;
 252                 unsigned int from_tag:1;
 253                 unsigned int deref:1;
 254         } *table;
 255         int nr;
 256         int alloc;
 257         int sorted;
 258 } tip_table;
 259
 260 static void add_to_tip_table(const struct object_id *oid, const char *refname,
 261                              int shorten_unambiguous, struct commit *commit,
 262                              timestamp_t taggerdate, int from_tag, int deref)
 263 {
 264         refname = name_ref_abbrev(refname, shorten_unambiguous);
 265
 266         ALLOC_GROW(tip_table.table, tip_table.nr + 1, tip_table.alloc);
 267         oidcpy(&tip_table.table[tip_table.nr].oid, oid);
 268         tip_table.table[tip_table.nr].refname = xstrdup(refname);
 269         tip_table.table[tip_table.nr].commit = commit;
 270         tip_table.table[tip_table.nr].taggerdate = taggerdate;
 271         tip_table.table[tip_table.nr].from_tag = from_tag;
 272         tip_table.table[tip_table.nr].deref = deref;
 273         tip_table.nr++;
 274         tip_table.sorted = 0;
 275 }
 276
 277 static int tipcmp(const void *a_, const void *b_)
 278 {
 279         const struct tip_table_entry *a = a_, *b = b_;
 280         return oidcmp(&a->oid, &b->oid);
 281 }
 282
 283 static int cmp_by_tag_and_age(const void *a_, const void *b_)
 284 {
 285         const struct tip_table_entry *a = a_, *b = b_;
 286         int cmp;
 287
 288         /* Prefer tags. */
 289         cmp = b->from_tag - a->from_tag;
 290         if (cmp)
 291                 return cmp;
 292
 293         /* Older is better. */
 294         if (a->taggerdate < b->taggerdate)
 295                 return -1;
 296         return a->taggerdate != b->taggerdate;
 297 }
 298
 299 static int name_ref(const char *path, const struct object_id *oid, int flags, void *cb_data)
 300 {
 301         struct object *o = parse_object(the_repository, oid);
 302         struct name_ref_data *data = cb_data;
 303         int can_abbreviate_output = data->tags_only && data->name_only;
 304         int deref = 0;
 305         int from_tag = 0;
 306         struct commit *commit = NULL;
 307         timestamp_t taggerdate = TIME_MAX;
 308
 309         if (data->tags_only && !starts_with(path, "refs/tags/"))
 310                 return 0;
 311
 312         if (data->exclude_filters.nr) {
 313                 struct string_list_item *item;
 314
 315                 for_each_string_list_item(item, &data->exclude_filters) {
 316                         if (subpath_matches(path, item->string) >= 0)
 317                                 return 0;
 318                 }
 319         }
 320
 321         if (data->ref_filters.nr) {
 322                 struct string_list_item *item;
 323                 int matched = 0;
 324
 325                 /* See if any of the patterns match. */
 326                 for_each_string_list_item(item, &data->ref_filters) {
 327                         /*
 328                          * Check all patterns even after finding a match, so
 329                          * that we can see if a match with a subpath exists.
 330                          * When a user asked for 'refs/tags/v*' and 'v1.*',
 331                          * both of which match, the user is showing her
 332                          * willingness to accept a shortened output by having
 333                          * the 'v1.*' in the acceptable refnames, so we
 334                          * shouldn't stop when seeing 'refs/tags/v1.4' matches
 335                          * 'refs/tags/v*'.  We should show it as 'v1.4'.
 336                          */
 337                         switch (subpath_matches(path, item->string)) {
 338                         case -1: /* did not match */
 339                                 break;
 340                         case 0: /* matched fully */
 341                                 matched = 1;
 342                                 break;
 343                         default: /* matched subpath */
 344                                 matched = 1;
 345                                 can_abbreviate_output = 1;
 346                                 break;
 347                         }
 348                 }
 349
 350                 /* If none of the patterns matched, stop now */
 351                 if (!matched)
 352                         return 0;
 353         }
 354
 355         while (o && o->type == OBJ_TAG) {
 356                 struct tag *t = (struct tag *) o;
 357                 if (!t->tagged)
 358                         break; /* broken repository */
 359                 o = parse_object(the_repository, &t->tagged->oid);
 360                 deref = 1;
 361                 taggerdate = t->date;
 362         }
 363         if (o && o->type == OBJ_COMMIT) {
 364                 commit = (struct commit *)o;
 365                 from_tag = starts_with(path, "refs/tags/");
 366                 if (taggerdate == TIME_MAX)
 367                         taggerdate = commit->date;
 368         }
 369
 370         add_to_tip_table(oid, path, can_abbreviate_output, commit, taggerdate,
 371                          from_tag, deref);
 372         return 0;
 373 }
 374
 375 static void name_tips(void)
 376 {
 377         int i;
 378
 379         /*
 380          * Try to set better names first, so that worse ones spread
 381          * less.
 382          */
 383         QSORT(tip_table.table, tip_table.nr, cmp_by_tag_and_age);
 384         for (i = 0; i < tip_table.nr; i++) {
 385                 struct tip_table_entry *e = &tip_table.table[i];
 386                 if (e->commit) {
 387                         name_rev(e->commit, e->refname, e->taggerdate,
 388                                  e->from_tag, e->deref);
 389                 }
 390         }
 391 }
 392
 393 static const unsigned char *nth_tip_table_ent(size_t ix, void *table_)
 394 {
 395         struct tip_table_entry *table = table_;
 396         return table[ix].oid.hash;
 397 }
 398
 399 static const char *get_exact_ref_match(const struct object *o)
 400 {
 401         int found;
 402
 403         if (!tip_table.table || !tip_table.nr)
 404                 return NULL;
 405
 406         if (!tip_table.sorted) {
 407                 QSORT(tip_table.table, tip_table.nr, tipcmp);
 408                 tip_table.sorted = 1;
 409         }
 410
 411         found = sha1_pos(o->oid.hash, tip_table.table, tip_table.nr,
 412                          nth_tip_table_ent);
 413         if (0 <= found)
 414                 return tip_table.table[found].refname;
 415         return NULL;
 416 }
 417
 418 /* may return a constant string or use "buf" as scratch space */
 419 static const char *get_rev_name(const struct object *o, struct strbuf *buf)
 420 {
 421         struct rev_name *n;
 422         const struct commit *c;
 423
 424         if (o->type != OBJ_COMMIT)
 425                 return get_exact_ref_match(o);
 426         c = (const struct commit *) o;
 427         n = get_commit_rev_name(c);
 428         if (!n)
 429                 return NULL;
 430
 431         if (!n->generation)
 432                 return n->tip_name;
 433         else {
 434                 strbuf_reset(buf);
 435                 strbuf_addstr(buf, n->tip_name);
 436                 strbuf_strip_suffix(buf, "^0");
 437                 strbuf_addf(buf, "~%d", n->generation);
 438                 return buf->buf;
 439         }
 440 }
 441
 442 static void show_name(const struct object *obj,
 443                       const char *caller_name,
 444                       int always, int allow_undefined, int name_only)
 445 {
 446         const char *name;
 447         const struct object_id *oid = &obj->oid;
 448         struct strbuf buf = STRBUF_INIT;
 449
 450         if (!name_only)
 451                 printf("%s ", caller_name ? caller_name : oid_to_hex(oid));
 452         name = get_rev_name(obj, &buf);
 453         if (name)
 454                 printf("%s\n", name);
 455         else if (allow_undefined)
 456                 printf("undefined\n");
 457         else if (always)
 458                 printf("%s\n", find_unique_abbrev(oid, DEFAULT_ABBREV));
 459         else
 460                 die("cannot describe '%s'", oid_to_hex(oid));
 461         strbuf_release(&buf);
 462 }
 463
 464 static char const * const name_rev_usage[] = {
 465         N_("git name-rev [<options>] <commit>..."),
 466         N_("git name-rev [<options>] --all"),
 467         N_("git name-rev [<options>] --stdin"),
 468         NULL
 469 };
 470
 471 static void name_rev_line(char *p, struct name_ref_data *data)
 472 {
 473         struct strbuf buf = STRBUF_INIT;
 474         int counter = 0;
 475         char *p_start;
 476         const unsigned hexsz = the_hash_algo->hexsz;
 477
 478         for (p_start = p; *p; p++) {
 479 #define ishex(x) (isdigit((x)) || ((x) >= 'a' && (x) <= 'f'))
 480                 if (!ishex(*p))
 481                         counter = 0;
 482                 else if (++counter == hexsz &&
 483                          !ishex(*(p+1))) {
 484                         struct object_id oid;
 485                         const char *name = NULL;
 486                         char c = *(p+1);
 487                         int p_len = p - p_start + 1;
 488
 489                         counter = 0;
 490
 491                         *(p+1) = 0;
 492                         if (!get_oid(p - (hexsz - 1), &oid)) {
 493                                 struct object *o =
 494                                         lookup_object(the_repository, &oid);
 495                                 if (o)
 496                                         name = get_rev_name(o, &buf);
 497                         }
 498                         *(p+1) = c;
 499
 500                         if (!name)
 501                                 continue;
 502
 503                         if (data->name_only)
 504                                 printf("%.*s%s", p_len - hexsz, p_start, name);
 505                         else
 506                                 printf("%.*s (%s)", p_len, p_start, name);
 507                         p_start = p + 1;
 508                 }
 509         }
 510
 511         /* flush */
 512         if (p_start != p)
 513                 fwrite(p_start, p - p_start, 1, stdout);
 514
 515         strbuf_release(&buf);
 516 }
 517
 518 int cmd_name_rev(int argc, const char **argv, const char *prefix)
 519 {
 520         struct object_array revs = OBJECT_ARRAY_INIT;
 521         int all = 0, transform_stdin = 0, allow_undefined = 1, always = 0, peel_tag = 0;
 522         struct name_ref_data data = { 0, 0, STRING_LIST_INIT_NODUP, STRING_LIST_INIT_NODUP };
 523         struct option opts[] = {
 524                 OPT_BOOL(0, "name-only", &data.name_only, N_("print only ref-based names (no object names)")),
 525                 OPT_BOOL(0, "tags", &data.tags_only, N_("only use tags to name the commits")),
 526                 OPT_STRING_LIST(0, "refs", &data.ref_filters, N_("pattern"),
 527                                    N_("only use refs matching <pattern>")),
 528                 OPT_STRING_LIST(0, "exclude", &data.exclude_filters, N_("pattern"),
 529                                    N_("ignore refs matching <pattern>")),
 530                 OPT_GROUP(""),
 531                 OPT_BOOL(0, "all", &all, N_("list all commits reachable from all refs")),
 532                 OPT_BOOL(0, "stdin", &transform_stdin, N_("read from stdin")),
 533                 OPT_BOOL(0, "undefined", &allow_undefined, N_("allow to print `undefined` names (default)")),
 534                 OPT_BOOL(0, "always",     &always,
 535                            N_("show abbreviated commit object as fallback")),
 536                 {
 537                         /* A Hidden OPT_BOOL */
 538                         OPTION_SET_INT, 0, "peel-tag", &peel_tag, NULL,
 539                         N_("dereference tags in the input (internal use)"),
 540                         PARSE_OPT_NOARG | PARSE_OPT_HIDDEN, NULL, 1,
 541                 },
 542                 OPT_END(),
 543         };
 544
 545         init_commit_rev_name(&rev_names);
 546         git_config(git_default_config, NULL);
 547         argc = parse_options(argc, argv, prefix, opts, name_rev_usage, 0);
 548         if (all + transform_stdin + !!argc > 1) {
 549                 error("Specify either a list, or --all, not both!");
 550                 usage_with_options(name_rev_usage, opts);
 551         }
 552         if (all || transform_stdin)
 553                 cutoff = 0;
 554
 555         for (; argc; argc--, argv++) {
 556                 struct object_id oid;
 557                 struct object *object;
 558                 struct commit *commit;
 559
 560                 if (get_oid(*argv, &oid)) {
 561                         fprintf(stderr, "Could not get sha1 for %s. Skipping.\n",
 562                                         *argv);
 563                         continue;
 564                 }
 565
 566                 commit = NULL;
 567                 object = parse_object(the_repository, &oid);
 568                 if (object) {
 569                         struct object *peeled = deref_tag(the_repository,
 570                                                           object, *argv, 0);
 571                         if (peeled && peeled->type == OBJ_COMMIT)
 572                                 commit = (struct commit *)peeled;
 573                 }
 574
 575                 if (!object) {
 576                         fprintf(stderr, "Could not get object for %s. Skipping.\n",
 577                                         *argv);
 578                         continue;
 579                 }
 580
 581                 if (commit) {
 582                         if (cutoff > commit->date)
 583                                 cutoff = commit->date;
 584                 }
 585
 586                 if (peel_tag) {
 587                         if (!commit) {
 588                                 fprintf(stderr, "Could not get commit for %s. Skipping.\n",
 589                                         *argv);
 590                                 continue;
 591                         }
 592                         object = (struct object *)commit;
 593                 }
 594                 add_object_array(object, *argv, &revs);
 595         }
 596
 597         if (cutoff) {
 598                 /* check for undeflow */
 599                 if (cutoff > TIME_MIN + CUTOFF_DATE_SLOP)
 600                         cutoff = cutoff - CUTOFF_DATE_SLOP;
 601                 else
 602                         cutoff = TIME_MIN;
 603         }
 604         for_each_ref(name_ref, &data);
 605         name_tips();
 606
 607         if (transform_stdin) {
 608                 char buffer[2048];
 609
 610                 while (!feof(stdin)) {
 611                         char *p = fgets(buffer, sizeof(buffer), stdin);
 612                         if (!p)
 613                                 break;
 614                         name_rev_line(p, &data);
 615                 }
 616         } else if (all) {
 617                 int i, max;
 618
 619                 max = get_max_object_index();
 620                 for (i = 0; i < max; i++) {
 621                         struct object *obj = get_indexed_object(i);
 622                         if (!obj || obj->type != OBJ_COMMIT)
 623                                 continue;
 624                         show_name(obj, NULL,
 625                                   always, allow_undefined, data.name_only);
 626                 }
 627         } else {
 628                 int i;
 629                 for (i = 0; i < revs.nr; i++)
 630                         show_name(revs.objects[i].item, revs.objects[i].name,
 631                                   always, allow_undefined, data.name_only);
 632         }
 633
 634         UNLEAK(revs);
 635         return 0;
 636 }