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 #include "commit-graph.h"
  13
  14 /*
  15  * One day.  See the 'name a rev shortly after epoch' test in t6120 when
  16  * changing this value
  17  */
  18 #define CUTOFF_DATE_SLOP 86400
  19
  20 struct rev_name {
  21         const char *tip_name;
  22         timestamp_t taggerdate;
  23         int generation;
  24         int distance;
  25         int from_tag;
  26 };
  27
  28 define_commit_slab(commit_rev_name, struct rev_name);
  29
  30 static timestamp_t generation_cutoff = GENERATION_NUMBER_INFINITY;
  31 static timestamp_t cutoff = TIME_MAX;
  32 static struct commit_rev_name rev_names;
  33
  34 /* Disable the cutoff checks entirely */
  35 static void disable_cutoff(void)
  36 {
  37         generation_cutoff = 0;
  38         cutoff = 0;
  39 }
  40
  41 /* Cutoff searching any commits older than this one */
  42 static void set_commit_cutoff(struct commit *commit)
  43 {
  44
  45         if (cutoff > commit->date)
  46                 cutoff = commit->date;
  47
  48         if (generation_cutoff) {
  49                 timestamp_t generation = commit_graph_generation(commit);
  50
  51                 if (generation_cutoff > generation)
  52                         generation_cutoff = generation;
  53         }
  54 }
  55
  56 /* adjust the commit date cutoff with a slop to allow for slightly incorrect
  57  * commit timestamps in case of clock skew.
  58  */
  59 static void adjust_cutoff_timestamp_for_slop(void)
  60 {
  61         if (cutoff) {
  62                 /* check for undeflow */
  63                 if (cutoff > TIME_MIN + CUTOFF_DATE_SLOP)
  64                         cutoff = cutoff - CUTOFF_DATE_SLOP;
  65                 else
  66                         cutoff = TIME_MIN;
  67         }
  68 }
  69
  70 /* Check if a commit is before the cutoff. Prioritize generation numbers
  71  * first, but use the commit timestamp if we lack generation data.
  72  */
  73 static int commit_is_before_cutoff(struct commit *commit)
  74 {
  75         if (generation_cutoff < GENERATION_NUMBER_INFINITY)
  76                 return generation_cutoff &&
  77                         commit_graph_generation(commit) < generation_cutoff;
  78
  79         return commit->date < cutoff;
  80 }
  81
  82 /* How many generations are maximally preferred over _one_ merge traversal? */
  83 #define MERGE_TRAVERSAL_WEIGHT 65535
  84
  85 static int is_valid_rev_name(const struct rev_name *name)
  86 {
  87         return name && name->tip_name;
  88 }
  89
  90 static struct rev_name *get_commit_rev_name(const struct commit *commit)
  91 {
  92         struct rev_name *name = commit_rev_name_peek(&rev_names, commit);
  93
  94         return is_valid_rev_name(name) ? name : NULL;
  95 }
  96
  97 static int effective_distance(int distance, int generation)
  98 {
  99         return distance + (generation > 0 ? MERGE_TRAVERSAL_WEIGHT : 0);
 100 }
 101
 102 static int is_better_name(struct rev_name *name,
 103                           timestamp_t taggerdate,
 104                           int generation,
 105                           int distance,
 106                           int from_tag)
 107 {
 108         int name_distance = effective_distance(name->distance, name->generation);
 109         int new_distance = effective_distance(distance, generation);
 110
 111         /*
 112          * When comparing names based on tags, prefer names
 113          * based on the older tag, even if it is farther away.
 114          */
 115         if (from_tag && name->from_tag)
 116                 return (name->taggerdate > taggerdate ||
 117                         (name->taggerdate == taggerdate &&
 118                          name_distance > new_distance));
 119
 120         /*
 121          * We know that at least one of them is a non-tag at this point.
 122          * favor a tag over a non-tag.
 123          */
 124         if (name->from_tag != from_tag)
 125                 return from_tag;
 126
 127         /*
 128          * We are now looking at two non-tags.  Tiebreak to favor
 129          * shorter hops.
 130          */
 131         if (name_distance != new_distance)
 132                 return name_distance > new_distance;
 133
 134         /* ... or tiebreak to favor older date */
 135         if (name->taggerdate != taggerdate)
 136                 return name->taggerdate > taggerdate;
 137
 138         /* keep the current one if we cannot decide */
 139         return 0;
 140 }
 141
 142 static struct rev_name *create_or_update_name(struct commit *commit,
 143                                               timestamp_t taggerdate,
 144                                               int generation, int distance,
 145                                               int from_tag)
 146 {
 147         struct rev_name *name = commit_rev_name_at(&rev_names, commit);
 148
 149         if (is_valid_rev_name(name) &&
 150             !is_better_name(name, taggerdate, generation, distance, from_tag))
 151                 return NULL;
 152
 153         name->taggerdate = taggerdate;
 154         name->generation = generation;
 155         name->distance = distance;
 156         name->from_tag = from_tag;
 157
 158         return name;
 159 }
 160
 161 static char *get_parent_name(const struct rev_name *name, int parent_number)
 162 {
 163         struct strbuf sb = STRBUF_INIT;
 164         size_t len;
 165
 166         strip_suffix(name->tip_name, "^0", &len);
 167         if (name->generation > 0) {
 168                 strbuf_grow(&sb, len +
 169                             1 + decimal_width(name->generation) +
 170                             1 + decimal_width(parent_number));
 171                 strbuf_addf(&sb, "%.*s~%d^%d", (int)len, name->tip_name,
 172                             name->generation, parent_number);
 173         } else {
 174                 strbuf_grow(&sb, len +
 175                             1 + decimal_width(parent_number));
 176                 strbuf_addf(&sb, "%.*s^%d", (int)len, name->tip_name,
 177                             parent_number);
 178         }
 179         return strbuf_detach(&sb, NULL);
 180 }
 181
 182 static void name_rev(struct commit *start_commit,
 183                 const char *tip_name, timestamp_t taggerdate,
 184                 int from_tag, int deref)
 185 {
 186         struct prio_queue queue;
 187         struct commit *commit;
 188         struct commit **parents_to_queue = NULL;
 189         size_t parents_to_queue_nr, parents_to_queue_alloc = 0;
 190         struct rev_name *start_name;
 191
 192         parse_commit(start_commit);
 193         if (commit_is_before_cutoff(start_commit))
 194                 return;
 195
 196         start_name = create_or_update_name(start_commit, taggerdate, 0, 0,
 197                                            from_tag);
 198         if (!start_name)
 199                 return;
 200         if (deref)
 201                 start_name->tip_name = xstrfmt("%s^0", tip_name);
 202         else
 203                 start_name->tip_name = xstrdup(tip_name);
 204
 205         memset(&queue, 0, sizeof(queue)); /* Use the prio_queue as LIFO */
 206         prio_queue_put(&queue, start_commit);
 207
 208         while ((commit = prio_queue_get(&queue))) {
 209                 struct rev_name *name = get_commit_rev_name(commit);
 210                 struct commit_list *parents;
 211                 int parent_number = 1;
 212
 213                 parents_to_queue_nr = 0;
 214
 215                 for (parents = commit->parents;
 216                                 parents;
 217                                 parents = parents->next, parent_number++) {
 218                         struct commit *parent = parents->item;
 219                         struct rev_name *parent_name;
 220                         int generation, distance;
 221
 222                         parse_commit(parent);
 223                         if (commit_is_before_cutoff(parent))
 224                                 continue;
 225
 226                         if (parent_number > 1) {
 227                                 generation = 0;
 228                                 distance = name->distance + MERGE_TRAVERSAL_WEIGHT;
 229                         } else {
 230                                 generation = name->generation + 1;
 231                                 distance = name->distance + 1;
 232                         }
 233
 234                         parent_name = create_or_update_name(parent, taggerdate,
 235                                                             generation,
 236                                                             distance, from_tag);
 237                         if (parent_name) {
 238                                 if (parent_number > 1)
 239                                         parent_name->tip_name =
 240                                                 get_parent_name(name,
 241                                                                 parent_number);
 242                                 else
 243                                         parent_name->tip_name = name->tip_name;
 244                                 ALLOC_GROW(parents_to_queue,
 245                                            parents_to_queue_nr + 1,
 246                                            parents_to_queue_alloc);
 247                                 parents_to_queue[parents_to_queue_nr] = parent;
 248                                 parents_to_queue_nr++;
 249                         }
 250                 }
 251
 252                 /* The first parent must come out first from the prio_queue */
 253                 while (parents_to_queue_nr)
 254                         prio_queue_put(&queue,
 255                                        parents_to_queue[--parents_to_queue_nr]);
 256         }
 257
 258         clear_prio_queue(&queue);
 259         free(parents_to_queue);
 260 }
 261
 262 static int subpath_matches(const char *path, const char *filter)
 263 {
 264         const char *subpath = path;
 265
 266         while (subpath) {
 267                 if (!wildmatch(filter, subpath, 0))
 268                         return subpath - path;
 269                 subpath = strchr(subpath, '/');
 270                 if (subpath)
 271                         subpath++;
 272         }
 273         return -1;
 274 }
 275
 276 static const char *name_ref_abbrev(const char *refname, int shorten_unambiguous)
 277 {
 278         if (shorten_unambiguous)
 279                 refname = shorten_unambiguous_ref(refname, 0);
 280         else if (skip_prefix(refname, "refs/heads/", &refname))
 281                 ; /* refname already advanced */
 282         else
 283                 skip_prefix(refname, "refs/", &refname);
 284         return refname;
 285 }
 286
 287 struct name_ref_data {
 288         int tags_only;
 289         int name_only;
 290         struct string_list ref_filters;
 291         struct string_list exclude_filters;
 292 };
 293
 294 static struct tip_table {
 295         struct tip_table_entry {
 296                 struct object_id oid;
 297                 const char *refname;
 298                 struct commit *commit;
 299                 timestamp_t taggerdate;
 300                 unsigned int from_tag:1;
 301                 unsigned int deref:1;
 302         } *table;
 303         int nr;
 304         int alloc;
 305         int sorted;
 306 } tip_table;
 307
 308 static void add_to_tip_table(const struct object_id *oid, const char *refname,
 309                              int shorten_unambiguous, struct commit *commit,
 310                              timestamp_t taggerdate, int from_tag, int deref)
 311 {
 312         refname = name_ref_abbrev(refname, shorten_unambiguous);
 313
 314         ALLOC_GROW(tip_table.table, tip_table.nr + 1, tip_table.alloc);
 315         oidcpy(&tip_table.table[tip_table.nr].oid, oid);
 316         tip_table.table[tip_table.nr].refname = xstrdup(refname);
 317         tip_table.table[tip_table.nr].commit = commit;
 318         tip_table.table[tip_table.nr].taggerdate = taggerdate;
 319         tip_table.table[tip_table.nr].from_tag = from_tag;
 320         tip_table.table[tip_table.nr].deref = deref;
 321         tip_table.nr++;
 322         tip_table.sorted = 0;
 323 }
 324
 325 static int tipcmp(const void *a_, const void *b_)
 326 {
 327         const struct tip_table_entry *a = a_, *b = b_;
 328         return oidcmp(&a->oid, &b->oid);
 329 }
 330
 331 static int cmp_by_tag_and_age(const void *a_, const void *b_)
 332 {
 333         const struct tip_table_entry *a = a_, *b = b_;
 334         int cmp;
 335
 336         /* Prefer tags. */
 337         cmp = b->from_tag - a->from_tag;
 338         if (cmp)
 339                 return cmp;
 340
 341         /* Older is better. */
 342         if (a->taggerdate < b->taggerdate)
 343                 return -1;
 344         return a->taggerdate != b->taggerdate;
 345 }
 346
 347 static int name_ref(const char *path, const struct object_id *oid,
 348                     int UNUSED(flags), void *cb_data)
 349 {
 350         struct object *o = parse_object(the_repository, oid);
 351         struct name_ref_data *data = cb_data;
 352         int can_abbreviate_output = data->tags_only && data->name_only;
 353         int deref = 0;
 354         int from_tag = 0;
 355         struct commit *commit = NULL;
 356         timestamp_t taggerdate = TIME_MAX;
 357
 358         if (data->tags_only && !starts_with(path, "refs/tags/"))
 359                 return 0;
 360
 361         if (data->exclude_filters.nr) {
 362                 struct string_list_item *item;
 363
 364                 for_each_string_list_item(item, &data->exclude_filters) {
 365                         if (subpath_matches(path, item->string) >= 0)
 366                                 return 0;
 367                 }
 368         }
 369
 370         if (data->ref_filters.nr) {
 371                 struct string_list_item *item;
 372                 int matched = 0;
 373
 374                 /* See if any of the patterns match. */
 375                 for_each_string_list_item(item, &data->ref_filters) {
 376                         /*
 377                          * Check all patterns even after finding a match, so
 378                          * that we can see if a match with a subpath exists.
 379                          * When a user asked for 'refs/tags/v*' and 'v1.*',
 380                          * both of which match, the user is showing her
 381                          * willingness to accept a shortened output by having
 382                          * the 'v1.*' in the acceptable refnames, so we
 383                          * shouldn't stop when seeing 'refs/tags/v1.4' matches
 384                          * 'refs/tags/v*'.  We should show it as 'v1.4'.
 385                          */
 386                         switch (subpath_matches(path, item->string)) {
 387                         case -1: /* did not match */
 388                                 break;
 389                         case 0: /* matched fully */
 390                                 matched = 1;
 391                                 break;
 392                         default: /* matched subpath */
 393                                 matched = 1;
 394                                 can_abbreviate_output = 1;
 395                                 break;
 396                         }
 397                 }
 398
 399                 /* If none of the patterns matched, stop now */
 400                 if (!matched)
 401                         return 0;
 402         }
 403
 404         while (o && o->type == OBJ_TAG) {
 405                 struct tag *t = (struct tag *) o;
 406                 if (!t->tagged)
 407                         break; /* broken repository */
 408                 o = parse_object(the_repository, &t->tagged->oid);
 409                 deref = 1;
 410                 taggerdate = t->date;
 411         }
 412         if (o && o->type == OBJ_COMMIT) {
 413                 commit = (struct commit *)o;
 414                 from_tag = starts_with(path, "refs/tags/");
 415                 if (taggerdate == TIME_MAX)
 416                         taggerdate = commit->date;
 417         }
 418
 419         add_to_tip_table(oid, path, can_abbreviate_output, commit, taggerdate,
 420                          from_tag, deref);
 421         return 0;
 422 }
 423
 424 static void name_tips(void)
 425 {
 426         int i;
 427
 428         /*
 429          * Try to set better names first, so that worse ones spread
 430          * less.
 431          */
 432         QSORT(tip_table.table, tip_table.nr, cmp_by_tag_and_age);
 433         for (i = 0; i < tip_table.nr; i++) {
 434                 struct tip_table_entry *e = &tip_table.table[i];
 435                 if (e->commit) {
 436                         name_rev(e->commit, e->refname, e->taggerdate,
 437                                  e->from_tag, e->deref);
 438                 }
 439         }
 440 }
 441
 442 static const struct object_id *nth_tip_table_ent(size_t ix, const void *table_)
 443 {
 444         const struct tip_table_entry *table = table_;
 445         return &table[ix].oid;
 446 }
 447
 448 static const char *get_exact_ref_match(const struct object *o)
 449 {
 450         int found;
 451
 452         if (!tip_table.table || !tip_table.nr)
 453                 return NULL;
 454
 455         if (!tip_table.sorted) {
 456                 QSORT(tip_table.table, tip_table.nr, tipcmp);
 457                 tip_table.sorted = 1;
 458         }
 459
 460         found = oid_pos(&o->oid, tip_table.table, tip_table.nr,
 461                         nth_tip_table_ent);
 462         if (0 <= found)
 463                 return tip_table.table[found].refname;
 464         return NULL;
 465 }
 466
 467 /* may return a constant string or use "buf" as scratch space */
 468 static const char *get_rev_name(const struct object *o, struct strbuf *buf)
 469 {
 470         struct rev_name *n;
 471         const struct commit *c;
 472
 473         if (o->type != OBJ_COMMIT)
 474                 return get_exact_ref_match(o);
 475         c = (const struct commit *) o;
 476         n = get_commit_rev_name(c);
 477         if (!n)
 478                 return NULL;
 479
 480         if (!n->generation)
 481                 return n->tip_name;
 482         else {
 483                 strbuf_reset(buf);
 484                 strbuf_addstr(buf, n->tip_name);
 485                 strbuf_strip_suffix(buf, "^0");
 486                 strbuf_addf(buf, "~%d", n->generation);
 487                 return buf->buf;
 488         }
 489 }
 490
 491 static void show_name(const struct object *obj,
 492                       const char *caller_name,
 493                       int always, int allow_undefined, int name_only)
 494 {
 495         const char *name;
 496         const struct object_id *oid = &obj->oid;
 497         struct strbuf buf = STRBUF_INIT;
 498
 499         if (!name_only)
 500                 printf("%s ", caller_name ? caller_name : oid_to_hex(oid));
 501         name = get_rev_name(obj, &buf);
 502         if (name)
 503                 printf("%s\n", name);
 504         else if (allow_undefined)
 505                 printf("undefined\n");
 506         else if (always)
 507                 printf("%s\n", find_unique_abbrev(oid, DEFAULT_ABBREV));
 508         else
 509                 die("cannot describe '%s'", oid_to_hex(oid));
 510         strbuf_release(&buf);
 511 }
 512
 513 static char const * const name_rev_usage[] = {
 514         N_("git name-rev [<options>] <commit>..."),
 515         N_("git name-rev [<options>] --all"),
 516         N_("git name-rev [<options>] --annotate-stdin"),
 517         NULL
 518 };
 519
 520 static void name_rev_line(char *p, struct name_ref_data *data)
 521 {
 522         struct strbuf buf = STRBUF_INIT;
 523         int counter = 0;
 524         char *p_start;
 525         const unsigned hexsz = the_hash_algo->hexsz;
 526
 527         for (p_start = p; *p; p++) {
 528 #define ishex(x) (isdigit((x)) || ((x) >= 'a' && (x) <= 'f'))
 529                 if (!ishex(*p))
 530                         counter = 0;
 531                 else if (++counter == hexsz &&
 532                          !ishex(*(p+1))) {
 533                         struct object_id oid;
 534                         const char *name = NULL;
 535                         char c = *(p+1);
 536                         int p_len = p - p_start + 1;
 537
 538                         counter = 0;
 539
 540                         *(p+1) = 0;
 541                         if (!get_oid(p - (hexsz - 1), &oid)) {
 542                                 struct object *o =
 543                                         lookup_object(the_repository, &oid);
 544                                 if (o)
 545                                         name = get_rev_name(o, &buf);
 546                         }
 547                         *(p+1) = c;
 548
 549                         if (!name)
 550                                 continue;
 551
 552                         if (data->name_only)
 553                                 printf("%.*s%s", p_len - hexsz, p_start, name);
 554                         else
 555                                 printf("%.*s (%s)", p_len, p_start, name);
 556                         p_start = p + 1;
 557                 }
 558         }
 559
 560         /* flush */
 561         if (p_start != p)
 562                 fwrite(p_start, p - p_start, 1, stdout);
 563
 564         strbuf_release(&buf);
 565 }
 566
 567 int cmd_name_rev(int argc, const char **argv, const char *prefix)
 568 {
 569         struct object_array revs = OBJECT_ARRAY_INIT;
 570         int all = 0, annotate_stdin = 0, transform_stdin = 0, allow_undefined = 1, always = 0, peel_tag = 0;
 571         struct name_ref_data data = { 0, 0, STRING_LIST_INIT_NODUP, STRING_LIST_INIT_NODUP };
 572         struct option opts[] = {
 573                 OPT_BOOL(0, "name-only", &data.name_only, N_("print only ref-based names (no object names)")),
 574                 OPT_BOOL(0, "tags", &data.tags_only, N_("only use tags to name the commits")),
 575                 OPT_STRING_LIST(0, "refs", &data.ref_filters, N_("pattern"),
 576                                    N_("only use refs matching <pattern>")),
 577                 OPT_STRING_LIST(0, "exclude", &data.exclude_filters, N_("pattern"),
 578                                    N_("ignore refs matching <pattern>")),
 579                 OPT_GROUP(""),
 580                 OPT_BOOL(0, "all", &all, N_("list all commits reachable from all refs")),
 581                 OPT_BOOL(0, "stdin", &transform_stdin, N_("deprecated: use --annotate-stdin instead")),
 582                 OPT_BOOL(0, "annotate-stdin", &annotate_stdin, N_("annotate text from stdin")),
 583                 OPT_BOOL(0, "undefined", &allow_undefined, N_("allow to print `undefined` names (default)")),
 584                 OPT_BOOL(0, "always",     &always,
 585                            N_("show abbreviated commit object as fallback")),
 586                 {
 587                         /* A Hidden OPT_BOOL */
 588                         OPTION_SET_INT, 0, "peel-tag", &peel_tag, NULL,
 589                         N_("dereference tags in the input (internal use)"),
 590                         PARSE_OPT_NOARG | PARSE_OPT_HIDDEN, NULL, 1,
 591                 },
 592                 OPT_END(),
 593         };
 594
 595         init_commit_rev_name(&rev_names);
 596         git_config(git_default_config, NULL);
 597         argc = parse_options(argc, argv, prefix, opts, name_rev_usage, 0);
 598
 599         if (transform_stdin) {
 600                 warning("--stdin is deprecated. Please use --annotate-stdin instead, "
 601                                         "which is functionally equivalent.\n"
 602                                         "This option will be removed in a future release.");
 603                 annotate_stdin = 1;
 604         }
 605
 606         if (all + annotate_stdin + !!argc > 1) {
 607                 error("Specify either a list, or --all, not both!");
 608                 usage_with_options(name_rev_usage, opts);
 609         }
 610         if (all || annotate_stdin)
 611                 disable_cutoff();
 612
 613         for (; argc; argc--, argv++) {
 614                 struct object_id oid;
 615                 struct object *object;
 616                 struct commit *commit;
 617
 618                 if (get_oid(*argv, &oid)) {
 619                         fprintf(stderr, "Could not get sha1 for %s. Skipping.\n",
 620                                         *argv);
 621                         continue;
 622                 }
 623
 624                 commit = NULL;
 625                 object = parse_object(the_repository, &oid);
 626                 if (object) {
 627                         struct object *peeled = deref_tag(the_repository,
 628                                                           object, *argv, 0);
 629                         if (peeled && peeled->type == OBJ_COMMIT)
 630                                 commit = (struct commit *)peeled;
 631                 }
 632
 633                 if (!object) {
 634                         fprintf(stderr, "Could not get object for %s. Skipping.\n",
 635                                         *argv);
 636                         continue;
 637                 }
 638
 639                 if (commit)
 640                         set_commit_cutoff(commit);
 641
 642                 if (peel_tag) {
 643                         if (!commit) {
 644                                 fprintf(stderr, "Could not get commit for %s. Skipping.\n",
 645                                         *argv);
 646                                 continue;
 647                         }
 648                         object = (struct object *)commit;
 649                 }
 650                 add_object_array(object, *argv, &revs);
 651         }
 652
 653         adjust_cutoff_timestamp_for_slop();
 654
 655         for_each_ref(name_ref, &data);
 656         name_tips();
 657
 658         if (annotate_stdin) {
 659                 struct strbuf sb = STRBUF_INIT;
 660
 661                 while (strbuf_getline(&sb, stdin) != EOF) {
 662                         strbuf_addch(&sb, '\n');
 663                         name_rev_line(sb.buf, &data);
 664                 }
 665                 strbuf_release(&sb);
 666         } else if (all) {
 667                 int i, max;
 668
 669                 max = get_max_object_index();
 670                 for (i = 0; i < max; i++) {
 671                         struct object *obj = get_indexed_object(i);
 672                         if (!obj || obj->type != OBJ_COMMIT)
 673                                 continue;
 674                         show_name(obj, NULL,
 675                                   always, allow_undefined, data.name_only);
 676                 }
 677         } else {
 678                 int i;
 679                 for (i = 0; i < revs.nr; i++)
 680                         show_name(revs.objects[i].item, revs.objects[i].name,
 681                                   always, allow_undefined, data.name_only);
 682         }
 683
 684         UNLEAK(revs);
 685         return 0;
 686 }