builtin/name-rev.c

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