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 "hash-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 effective_distance(int distance, int generation)
  48 {
  49         return distance + (generation > 0 ? MERGE_TRAVERSAL_WEIGHT : 0);
  50 }
  51
  52 static int is_better_name(struct rev_name *name,
  53                           timestamp_t taggerdate,
  54                           int generation,
  55                           int distance,
  56                           int from_tag)
  57 {
  58         int name_distance = effective_distance(name->distance, name->generation);
  59         int new_distance = effective_distance(distance, generation);
  60
  61         /*
  62          * When comparing names based on tags, prefer names
  63          * based on the older tag, even if it is farther away.
  64          */
  65         if (from_tag && name->from_tag)
  66                 return (name->taggerdate > taggerdate ||
  67                         (name->taggerdate == taggerdate &&
  68                          name_distance > new_distance));
  69
  70         /*
  71          * We know that at least one of them is a non-tag at this point.
  72          * favor a tag over a non-tag.
  73          */
  74         if (name->from_tag != from_tag)
  75                 return from_tag;
  76
  77         /*
  78          * We are now looking at two non-tags.  Tiebreak to favor
  79          * shorter hops.
  80          */
  81         if (name_distance != new_distance)
  82                 return name_distance > new_distance;
  83
  84         /* ... or tiebreak to favor older date */
  85         if (name->taggerdate != taggerdate)
  86                 return name->taggerdate > taggerdate;
  87
  88         /* keep the current one if we cannot decide */
  89         return 0;
  90 }
  91
  92 static struct rev_name *create_or_update_name(struct commit *commit,
  93                                               timestamp_t taggerdate,
  94                                               int generation, int distance,
  95                                               int from_tag)
  96 {
  97         struct rev_name *name = commit_rev_name_at(&rev_names, commit);
  98
  99         if (is_valid_rev_name(name)) {
 100                 if (!is_better_name(name, taggerdate, generation, distance, from_tag))
 101                         return NULL;
 102
 103                 /*
 104                  * This string might still be shared with ancestors
 105                  * (generation > 0).  We can release it here regardless,
 106                  * because the new name that has just won will be better
 107                  * for them as well, so name_rev() will replace these
 108                  * stale pointers when it processes the parents.
 109                  */
 110                 if (!name->generation)
 111                         free(name->tip_name);
 112         }
 113
 114         name->taggerdate = taggerdate;
 115         name->generation = generation;
 116         name->distance = distance;
 117         name->from_tag = from_tag;
 118
 119         return name;
 120 }
 121
 122 static char *get_parent_name(const struct rev_name *name, int parent_number)
 123 {
 124         struct strbuf sb = STRBUF_INIT;
 125         size_t len;
 126
 127         strip_suffix(name->tip_name, "^0", &len);
 128         if (name->generation > 0) {
 129                 strbuf_grow(&sb, len +
 130                             1 + decimal_width(name->generation) +
 131                             1 + decimal_width(parent_number));
 132                 strbuf_addf(&sb, "%.*s~%d^%d", (int)len, name->tip_name,
 133                             name->generation, parent_number);
 134         } else {
 135                 strbuf_grow(&sb, len +
 136                             1 + decimal_width(parent_number));
 137                 strbuf_addf(&sb, "%.*s^%d", (int)len, name->tip_name,
 138                             parent_number);
 139         }
 140         return strbuf_detach(&sb, NULL);
 141 }
 142
 143 static void name_rev(struct commit *start_commit,
 144                 const char *tip_name, timestamp_t taggerdate,
 145                 int from_tag, int deref)
 146 {
 147         struct prio_queue queue;
 148         struct commit *commit;
 149         struct commit **parents_to_queue = NULL;
 150         size_t parents_to_queue_nr, parents_to_queue_alloc = 0;
 151         struct rev_name *start_name;
 152
 153         parse_commit(start_commit);
 154         if (start_commit->date < cutoff)
 155                 return;
 156
 157         start_name = create_or_update_name(start_commit, taggerdate, 0, 0,
 158                                            from_tag);
 159         if (!start_name)
 160                 return;
 161         if (deref)
 162                 start_name->tip_name = xstrfmt("%s^0", tip_name);
 163         else
 164                 start_name->tip_name = xstrdup(tip_name);
 165
 166         memset(&queue, 0, sizeof(queue)); /* Use the prio_queue as LIFO */
 167         prio_queue_put(&queue, start_commit);
 168
 169         while ((commit = prio_queue_get(&queue))) {
 170                 struct rev_name *name = get_commit_rev_name(commit);
 171                 struct commit_list *parents;
 172                 int parent_number = 1;
 173
 174                 parents_to_queue_nr = 0;
 175
 176                 for (parents = commit->parents;
 177                                 parents;
 178                                 parents = parents->next, parent_number++) {
 179                         struct commit *parent = parents->item;
 180                         struct rev_name *parent_name;
 181                         int generation, distance;
 182
 183                         parse_commit(parent);
 184                         if (parent->date < cutoff)
 185                                 continue;
 186
 187                         if (parent_number > 1) {
 188                                 generation = 0;
 189                                 distance = name->distance + MERGE_TRAVERSAL_WEIGHT;
 190                         } else {
 191                                 generation = name->generation + 1;
 192                                 distance = name->distance + 1;
 193                         }
 194
 195                         parent_name = create_or_update_name(parent, taggerdate,
 196                                                             generation,
 197                                                             distance, from_tag);
 198                         if (parent_name) {
 199                                 if (parent_number > 1)
 200                                         parent_name->tip_name =
 201                                                 get_parent_name(name,
 202                                                                 parent_number);
 203                                 else
 204                                         parent_name->tip_name = name->tip_name;
 205                                 ALLOC_GROW(parents_to_queue,
 206                                            parents_to_queue_nr + 1,
 207                                            parents_to_queue_alloc);
 208                                 parents_to_queue[parents_to_queue_nr] = parent;
 209                                 parents_to_queue_nr++;
 210                         }
 211                 }
 212
 213                 /* The first parent must come out first from the prio_queue */
 214                 while (parents_to_queue_nr)
 215                         prio_queue_put(&queue,
 216                                        parents_to_queue[--parents_to_queue_nr]);
 217         }
 218
 219         clear_prio_queue(&queue);
 220         free(parents_to_queue);
 221 }
 222
 223 static int subpath_matches(const char *path, const char *filter)
 224 {
 225         const char *subpath = path;
 226
 227         while (subpath) {
 228                 if (!wildmatch(filter, subpath, 0))
 229                         return subpath - path;
 230                 subpath = strchr(subpath, '/');
 231                 if (subpath)
 232                         subpath++;
 233         }
 234         return -1;
 235 }
 236
 237 static const char *name_ref_abbrev(const char *refname, int shorten_unambiguous)
 238 {
 239         if (shorten_unambiguous)
 240                 refname = shorten_unambiguous_ref(refname, 0);
 241         else if (skip_prefix(refname, "refs/heads/", &refname))
 242                 ; /* refname already advanced */
 243         else
 244                 skip_prefix(refname, "refs/", &refname);
 245         return refname;
 246 }
 247
 248 struct name_ref_data {
 249         int tags_only;
 250         int name_only;
 251         struct string_list ref_filters;
 252         struct string_list exclude_filters;
 253 };
 254
 255 static struct tip_table {
 256         struct tip_table_entry {
 257                 struct object_id oid;
 258                 const char *refname;
 259                 struct commit *commit;
 260                 timestamp_t taggerdate;
 261                 unsigned int from_tag:1;
 262                 unsigned int deref:1;
 263         } *table;
 264         int nr;
 265         int alloc;
 266         int sorted;
 267 } tip_table;
 268
 269 static void add_to_tip_table(const struct object_id *oid, const char *refname,
 270                              int shorten_unambiguous, struct commit *commit,
 271                              timestamp_t taggerdate, int from_tag, int deref)
 272 {
 273         refname = name_ref_abbrev(refname, shorten_unambiguous);
 274
 275         ALLOC_GROW(tip_table.table, tip_table.nr + 1, tip_table.alloc);
 276         oidcpy(&tip_table.table[tip_table.nr].oid, oid);
 277         tip_table.table[tip_table.nr].refname = xstrdup(refname);
 278         tip_table.table[tip_table.nr].commit = commit;
 279         tip_table.table[tip_table.nr].taggerdate = taggerdate;
 280         tip_table.table[tip_table.nr].from_tag = from_tag;
 281         tip_table.table[tip_table.nr].deref = deref;
 282         tip_table.nr++;
 283         tip_table.sorted = 0;
 284 }
 285
 286 static int tipcmp(const void *a_, const void *b_)
 287 {
 288         const struct tip_table_entry *a = a_, *b = b_;
 289         return oidcmp(&a->oid, &b->oid);
 290 }
 291
 292 static int cmp_by_tag_and_age(const void *a_, const void *b_)
 293 {
 294         const struct tip_table_entry *a = a_, *b = b_;
 295         int cmp;
 296
 297         /* Prefer tags. */
 298         cmp = b->from_tag - a->from_tag;
 299         if (cmp)
 300                 return cmp;
 301
 302         /* Older is better. */
 303         if (a->taggerdate < b->taggerdate)
 304                 return -1;
 305         return a->taggerdate != b->taggerdate;
 306 }
 307
 308 static int name_ref(const char *path, const struct object_id *oid, int flags, void *cb_data)
 309 {
 310         struct object *o = parse_object(the_repository, oid);
 311         struct name_ref_data *data = cb_data;
 312         int can_abbreviate_output = data->tags_only && data->name_only;
 313         int deref = 0;
 314         int from_tag = 0;
 315         struct commit *commit = NULL;
 316         timestamp_t taggerdate = TIME_MAX;
 317
 318         if (data->tags_only && !starts_with(path, "refs/tags/"))
 319                 return 0;
 320
 321         if (data->exclude_filters.nr) {
 322                 struct string_list_item *item;
 323
 324                 for_each_string_list_item(item, &data->exclude_filters) {
 325                         if (subpath_matches(path, item->string) >= 0)
 326                                 return 0;
 327                 }
 328         }
 329
 330         if (data->ref_filters.nr) {
 331                 struct string_list_item *item;
 332                 int matched = 0;
 333
 334                 /* See if any of the patterns match. */
 335                 for_each_string_list_item(item, &data->ref_filters) {
 336                         /*
 337                          * Check all patterns even after finding a match, so
 338                          * that we can see if a match with a subpath exists.
 339                          * When a user asked for 'refs/tags/v*' and 'v1.*',
 340                          * both of which match, the user is showing her
 341                          * willingness to accept a shortened output by having
 342                          * the 'v1.*' in the acceptable refnames, so we
 343                          * shouldn't stop when seeing 'refs/tags/v1.4' matches
 344                          * 'refs/tags/v*'.  We should show it as 'v1.4'.
 345                          */
 346                         switch (subpath_matches(path, item->string)) {
 347                         case -1: /* did not match */
 348                                 break;
 349                         case 0: /* matched fully */
 350                                 matched = 1;
 351                                 break;
 352                         default: /* matched subpath */
 353                                 matched = 1;
 354                                 can_abbreviate_output = 1;
 355                                 break;
 356                         }
 357                 }
 358
 359                 /* If none of the patterns matched, stop now */
 360                 if (!matched)
 361                         return 0;
 362         }
 363
 364         while (o && o->type == OBJ_TAG) {
 365                 struct tag *t = (struct tag *) o;
 366                 if (!t->tagged)
 367                         break; /* broken repository */
 368                 o = parse_object(the_repository, &t->tagged->oid);
 369                 deref = 1;
 370                 taggerdate = t->date;
 371         }
 372         if (o && o->type == OBJ_COMMIT) {
 373                 commit = (struct commit *)o;
 374                 from_tag = starts_with(path, "refs/tags/");
 375                 if (taggerdate == TIME_MAX)
 376                         taggerdate = commit->date;
 377         }
 378
 379         add_to_tip_table(oid, path, can_abbreviate_output, commit, taggerdate,
 380                          from_tag, deref);
 381         return 0;
 382 }
 383
 384 static void name_tips(void)
 385 {
 386         int i;
 387
 388         /*
 389          * Try to set better names first, so that worse ones spread
 390          * less.
 391          */
 392         QSORT(tip_table.table, tip_table.nr, cmp_by_tag_and_age);
 393         for (i = 0; i < tip_table.nr; i++) {
 394                 struct tip_table_entry *e = &tip_table.table[i];
 395                 if (e->commit) {
 396                         name_rev(e->commit, e->refname, e->taggerdate,
 397                                  e->from_tag, e->deref);
 398                 }
 399         }
 400 }
 401
 402 static const struct object_id *nth_tip_table_ent(size_t ix, const void *table_)
 403 {
 404         const struct tip_table_entry *table = table_;
 405         return &table[ix].oid;
 406 }
 407
 408 static const char *get_exact_ref_match(const struct object *o)
 409 {
 410         int found;
 411
 412         if (!tip_table.table || !tip_table.nr)
 413                 return NULL;
 414
 415         if (!tip_table.sorted) {
 416                 QSORT(tip_table.table, tip_table.nr, tipcmp);
 417                 tip_table.sorted = 1;
 418         }
 419
 420         found = oid_pos(&o->oid, tip_table.table, tip_table.nr,
 421                         nth_tip_table_ent);
 422         if (0 <= found)
 423                 return tip_table.table[found].refname;
 424         return NULL;
 425 }
 426
 427 /* may return a constant string or use "buf" as scratch space */
 428 static const char *get_rev_name(const struct object *o, struct strbuf *buf)
 429 {
 430         struct rev_name *n;
 431         const struct commit *c;
 432
 433         if (o->type != OBJ_COMMIT)
 434                 return get_exact_ref_match(o);
 435         c = (const struct commit *) o;
 436         n = get_commit_rev_name(c);
 437         if (!n)
 438                 return NULL;
 439
 440         if (!n->generation)
 441                 return n->tip_name;
 442         else {
 443                 strbuf_reset(buf);
 444                 strbuf_addstr(buf, n->tip_name);
 445                 strbuf_strip_suffix(buf, "^0");
 446                 strbuf_addf(buf, "~%d", n->generation);
 447                 return buf->buf;
 448         }
 449 }
 450
 451 static void show_name(const struct object *obj,
 452                       const char *caller_name,
 453                       int always, int allow_undefined, int name_only)
 454 {
 455         const char *name;
 456         const struct object_id *oid = &obj->oid;
 457         struct strbuf buf = STRBUF_INIT;
 458
 459         if (!name_only)
 460                 printf("%s ", caller_name ? caller_name : oid_to_hex(oid));
 461         name = get_rev_name(obj, &buf);
 462         if (name)
 463                 printf("%s\n", name);
 464         else if (allow_undefined)
 465                 printf("undefined\n");
 466         else if (always)
 467                 printf("%s\n", find_unique_abbrev(oid, DEFAULT_ABBREV));
 468         else
 469                 die("cannot describe '%s'", oid_to_hex(oid));
 470         strbuf_release(&buf);
 471 }
 472
 473 static char const * const name_rev_usage[] = {
 474         N_("git name-rev [<options>] <commit>..."),
 475         N_("git name-rev [<options>] --all"),
 476         N_("git name-rev [<options>] --stdin"),
 477         NULL
 478 };
 479
 480 static void name_rev_line(char *p, struct name_ref_data *data)
 481 {
 482         struct strbuf buf = STRBUF_INIT;
 483         int counter = 0;
 484         char *p_start;
 485         const unsigned hexsz = the_hash_algo->hexsz;
 486
 487         for (p_start = p; *p; p++) {
 488 #define ishex(x) (isdigit((x)) || ((x) >= 'a' && (x) <= 'f'))
 489                 if (!ishex(*p))
 490                         counter = 0;
 491                 else if (++counter == hexsz &&
 492                          !ishex(*(p+1))) {
 493                         struct object_id oid;
 494                         const char *name = NULL;
 495                         char c = *(p+1);
 496                         int p_len = p - p_start + 1;
 497
 498                         counter = 0;
 499
 500                         *(p+1) = 0;
 501                         if (!get_oid(p - (hexsz - 1), &oid)) {
 502                                 struct object *o =
 503                                         lookup_object(the_repository, &oid);
 504                                 if (o)
 505                                         name = get_rev_name(o, &buf);
 506                         }
 507                         *(p+1) = c;
 508
 509                         if (!name)
 510                                 continue;
 511
 512                         if (data->name_only)
 513                                 printf("%.*s%s", p_len - hexsz, p_start, name);
 514                         else
 515                                 printf("%.*s (%s)", p_len, p_start, name);
 516                         p_start = p + 1;
 517                 }
 518         }
 519
 520         /* flush */
 521         if (p_start != p)
 522                 fwrite(p_start, p - p_start, 1, stdout);
 523
 524         strbuf_release(&buf);
 525 }
 526
 527 int cmd_name_rev(int argc, const char **argv, const char *prefix)
 528 {
 529         struct object_array revs = OBJECT_ARRAY_INIT;
 530         int all = 0, transform_stdin = 0, allow_undefined = 1, always = 0, peel_tag = 0;
 531         struct name_ref_data data = { 0, 0, STRING_LIST_INIT_NODUP, STRING_LIST_INIT_NODUP };
 532         struct option opts[] = {
 533                 OPT_BOOL(0, "name-only", &data.name_only, N_("print only ref-based names (no object names)")),
 534                 OPT_BOOL(0, "tags", &data.tags_only, N_("only use tags to name the commits")),
 535                 OPT_STRING_LIST(0, "refs", &data.ref_filters, N_("pattern"),
 536                                    N_("only use refs matching <pattern>")),
 537                 OPT_STRING_LIST(0, "exclude", &data.exclude_filters, N_("pattern"),
 538                                    N_("ignore refs matching <pattern>")),
 539                 OPT_GROUP(""),
 540                 OPT_BOOL(0, "all", &all, N_("list all commits reachable from all refs")),
 541                 OPT_BOOL(0, "stdin", &transform_stdin, N_("read from stdin")),
 542                 OPT_BOOL(0, "undefined", &allow_undefined, N_("allow to print `undefined` names (default)")),
 543                 OPT_BOOL(0, "always",     &always,
 544                            N_("show abbreviated commit object as fallback")),
 545                 {
 546                         /* A Hidden OPT_BOOL */
 547                         OPTION_SET_INT, 0, "peel-tag", &peel_tag, NULL,
 548                         N_("dereference tags in the input (internal use)"),
 549                         PARSE_OPT_NOARG | PARSE_OPT_HIDDEN, NULL, 1,
 550                 },
 551                 OPT_END(),
 552         };
 553
 554         init_commit_rev_name(&rev_names);
 555         git_config(git_default_config, NULL);
 556         argc = parse_options(argc, argv, prefix, opts, name_rev_usage, 0);
 557         if (all + transform_stdin + !!argc > 1) {
 558                 error("Specify either a list, or --all, not both!");
 559                 usage_with_options(name_rev_usage, opts);
 560         }
 561         if (all || transform_stdin)
 562                 cutoff = 0;
 563
 564         for (; argc; argc--, argv++) {
 565                 struct object_id oid;
 566                 struct object *object;
 567                 struct commit *commit;
 568
 569                 if (get_oid(*argv, &oid)) {
 570                         fprintf(stderr, "Could not get sha1 for %s. Skipping.\n",
 571                                         *argv);
 572                         continue;
 573                 }
 574
 575                 commit = NULL;
 576                 object = parse_object(the_repository, &oid);
 577                 if (object) {
 578                         struct object *peeled = deref_tag(the_repository,
 579                                                           object, *argv, 0);
 580                         if (peeled && peeled->type == OBJ_COMMIT)
 581                                 commit = (struct commit *)peeled;
 582                 }
 583
 584                 if (!object) {
 585                         fprintf(stderr, "Could not get object for %s. Skipping.\n",
 586                                         *argv);
 587                         continue;
 588                 }
 589
 590                 if (commit) {
 591                         if (cutoff > commit->date)
 592                                 cutoff = commit->date;
 593                 }
 594
 595                 if (peel_tag) {
 596                         if (!commit) {
 597                                 fprintf(stderr, "Could not get commit for %s. Skipping.\n",
 598                                         *argv);
 599                                 continue;
 600                         }
 601                         object = (struct object *)commit;
 602                 }
 603                 add_object_array(object, *argv, &revs);
 604         }
 605
 606         if (cutoff) {
 607                 /* check for undeflow */
 608                 if (cutoff > TIME_MIN + CUTOFF_DATE_SLOP)
 609                         cutoff = cutoff - CUTOFF_DATE_SLOP;
 610                 else
 611                         cutoff = TIME_MIN;
 612         }
 613         for_each_ref(name_ref, &data);
 614         name_tips();
 615
 616         if (transform_stdin) {
 617                 char buffer[2048];
 618
 619                 while (!feof(stdin)) {
 620                         char *p = fgets(buffer, sizeof(buffer), stdin);
 621                         if (!p)
 622                                 break;
 623                         name_rev_line(p, &data);
 624                 }
 625         } else if (all) {
 626                 int i, max;
 627
 628                 max = get_max_object_index();
 629                 for (i = 0; i < max; i++) {
 630                         struct object *obj = get_indexed_object(i);
 631                         if (!obj || obj->type != OBJ_COMMIT)
 632                                 continue;
 633                         show_name(obj, NULL,
 634                                   always, allow_undefined, data.name_only);
 635                 }
 636         } else {
 637                 int i;
 638                 for (i = 0; i < revs.nr; i++)
 639                         show_name(revs.objects[i].item, revs.objects[i].name,
 640                                   always, allow_undefined, data.name_only);
 641         }
 642
 643         UNLEAK(revs);
 644         return 0;
 645 }