commit-reach.c

   1 #include "cache.h"
   2 #include "commit.h"
   3 #include "decorate.h"
   4 #include "prio-queue.h"
   5 #include "tree.h"
   6 #include "revision.h"
   7 #include "tag.h"
   8 #include "commit-reach.h"
   9
  10 /* Remember to update object flag allocation in object.h */
  11 #define PARENT1         (1u<<16)
  12 #define PARENT2         (1u<<17)
  13 #define STALE           (1u<<18)
  14 #define RESULT          (1u<<19)
  15
  16 static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
  17
  18 static int queue_has_nonstale(struct prio_queue *queue)
  19 {
  20         int i;
  21         for (i = 0; i < queue->nr; i++) {
  22                 struct commit *commit = queue->array[i].data;
  23                 if (!(commit->object.flags & STALE))
  24                         return 1;
  25         }
  26         return 0;
  27 }
  28
  29 /* all input commits in one and twos[] must have been parsed! */
  30 static struct commit_list *paint_down_to_common(struct commit *one, int n,
  31                                                 struct commit **twos,
  32                                                 int min_generation)
  33 {
  34         struct prio_queue queue = { compare_commits_by_gen_then_commit_date };
  35         struct commit_list *result = NULL;
  36         int i;
  37         uint32_t last_gen = GENERATION_NUMBER_INFINITY;
  38
  39         one->object.flags |= PARENT1;
  40         if (!n) {
  41                 commit_list_append(one, &result);
  42                 return result;
  43         }
  44         prio_queue_put(&queue, one);
  45
  46         for (i = 0; i < n; i++) {
  47                 twos[i]->object.flags |= PARENT2;
  48                 prio_queue_put(&queue, twos[i]);
  49         }
  50
  51         while (queue_has_nonstale(&queue)) {
  52                 struct commit *commit = prio_queue_get(&queue);
  53                 struct commit_list *parents;
  54                 int flags;
  55
  56                 if (commit->generation > last_gen)
  57                         BUG("bad generation skip %8x > %8x at %s",
  58                             commit->generation, last_gen,
  59                             oid_to_hex(&commit->object.oid));
  60                 last_gen = commit->generation;
  61
  62                 if (commit->generation < min_generation)
  63                         break;
  64
  65                 flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
  66                 if (flags == (PARENT1 | PARENT2)) {
  67                         if (!(commit->object.flags & RESULT)) {
  68                                 commit->object.flags |= RESULT;
  69                                 commit_list_insert_by_date(commit, &result);
  70                         }
  71                         /* Mark parents of a found merge stale */
  72                         flags |= STALE;
  73                 }
  74                 parents = commit->parents;
  75                 while (parents) {
  76                         struct commit *p = parents->item;
  77                         parents = parents->next;
  78                         if ((p->object.flags & flags) == flags)
  79                                 continue;
  80                         if (parse_commit(p))
  81                                 return NULL;
  82                         p->object.flags |= flags;
  83                         prio_queue_put(&queue, p);
  84                 }
  85         }
  86
  87         clear_prio_queue(&queue);
  88         return result;
  89 }
  90
  91 static struct commit_list *merge_bases_many(struct commit *one, int n, struct commit **twos)
  92 {
  93         struct commit_list *list = NULL;
  94         struct commit_list *result = NULL;
  95         int i;
  96
  97         for (i = 0; i < n; i++) {
  98                 if (one == twos[i])
  99                         /*
 100                          * We do not mark this even with RESULT so we do not
 101                          * have to clean it up.
 102                          */
 103                         return commit_list_insert(one, &result);
 104         }
 105
 106         if (parse_commit(one))
 107                 return NULL;
 108         for (i = 0; i < n; i++) {
 109                 if (parse_commit(twos[i]))
 110                         return NULL;
 111         }
 112
 113         list = paint_down_to_common(one, n, twos, 0);
 114
 115         while (list) {
 116                 struct commit *commit = pop_commit(&list);
 117                 if (!(commit->object.flags & STALE))
 118                         commit_list_insert_by_date(commit, &result);
 119         }
 120         return result;
 121 }
 122
 123 struct commit_list *get_octopus_merge_bases(struct commit_list *in)
 124 {
 125         struct commit_list *i, *j, *k, *ret = NULL;
 126
 127         if (!in)
 128                 return ret;
 129
 130         commit_list_insert(in->item, &ret);
 131
 132         for (i = in->next; i; i = i->next) {
 133                 struct commit_list *new_commits = NULL, *end = NULL;
 134
 135                 for (j = ret; j; j = j->next) {
 136                         struct commit_list *bases;
 137                         bases = get_merge_bases(i->item, j->item);
 138                         if (!new_commits)
 139                                 new_commits = bases;
 140                         else
 141                                 end->next = bases;
 142                         for (k = bases; k; k = k->next)
 143                                 end = k;
 144                 }
 145                 ret = new_commits;
 146         }
 147         return ret;
 148 }
 149
 150 static int remove_redundant(struct commit **array, int cnt)
 151 {
 152         /*
 153          * Some commit in the array may be an ancestor of
 154          * another commit.  Move such commit to the end of
 155          * the array, and return the number of commits that
 156          * are independent from each other.
 157          */
 158         struct commit **work;
 159         unsigned char *redundant;
 160         int *filled_index;
 161         int i, j, filled;
 162
 163         work = xcalloc(cnt, sizeof(*work));
 164         redundant = xcalloc(cnt, 1);
 165         ALLOC_ARRAY(filled_index, cnt - 1);
 166
 167         for (i = 0; i < cnt; i++)
 168                 parse_commit(array[i]);
 169         for (i = 0; i < cnt; i++) {
 170                 struct commit_list *common;
 171                 uint32_t min_generation = array[i]->generation;
 172
 173                 if (redundant[i])
 174                         continue;
 175                 for (j = filled = 0; j < cnt; j++) {
 176                         if (i == j || redundant[j])
 177                                 continue;
 178                         filled_index[filled] = j;
 179                         work[filled++] = array[j];
 180
 181                         if (array[j]->generation < min_generation)
 182                                 min_generation = array[j]->generation;
 183                 }
 184                 common = paint_down_to_common(array[i], filled, work,
 185                                               min_generation);
 186                 if (array[i]->object.flags & PARENT2)
 187                         redundant[i] = 1;
 188                 for (j = 0; j < filled; j++)
 189                         if (work[j]->object.flags & PARENT1)
 190                                 redundant[filled_index[j]] = 1;
 191                 clear_commit_marks(array[i], all_flags);
 192                 clear_commit_marks_many(filled, work, all_flags);
 193                 free_commit_list(common);
 194         }
 195
 196         /* Now collect the result */
 197         COPY_ARRAY(work, array, cnt);
 198         for (i = filled = 0; i < cnt; i++)
 199                 if (!redundant[i])
 200                         array[filled++] = work[i];
 201         for (j = filled, i = 0; i < cnt; i++)
 202                 if (redundant[i])
 203                         array[j++] = work[i];
 204         free(work);
 205         free(redundant);
 206         free(filled_index);
 207         return filled;
 208 }
 209
 210 static struct commit_list *get_merge_bases_many_0(struct commit *one,
 211                                                   int n,
 212                                                   struct commit **twos,
 213                                                   int cleanup)
 214 {
 215         struct commit_list *list;
 216         struct commit **rslt;
 217         struct commit_list *result;
 218         int cnt, i;
 219
 220         result = merge_bases_many(one, n, twos);
 221         for (i = 0; i < n; i++) {
 222                 if (one == twos[i])
 223                         return result;
 224         }
 225         if (!result || !result->next) {
 226                 if (cleanup) {
 227                         clear_commit_marks(one, all_flags);
 228                         clear_commit_marks_many(n, twos, all_flags);
 229                 }
 230                 return result;
 231         }
 232
 233         /* There are more than one */
 234         cnt = commit_list_count(result);
 235         rslt = xcalloc(cnt, sizeof(*rslt));
 236         for (list = result, i = 0; list; list = list->next)
 237                 rslt[i++] = list->item;
 238         free_commit_list(result);
 239
 240         clear_commit_marks(one, all_flags);
 241         clear_commit_marks_many(n, twos, all_flags);
 242
 243         cnt = remove_redundant(rslt, cnt);
 244         result = NULL;
 245         for (i = 0; i < cnt; i++)
 246                 commit_list_insert_by_date(rslt[i], &result);
 247         free(rslt);
 248         return result;
 249 }
 250
 251 struct commit_list *get_merge_bases_many(struct commit *one,
 252                                          int n,
 253                                          struct commit **twos)
 254 {
 255         return get_merge_bases_many_0(one, n, twos, 1);
 256 }
 257
 258 struct commit_list *get_merge_bases_many_dirty(struct commit *one,
 259                                                int n,
 260                                                struct commit **twos)
 261 {
 262         return get_merge_bases_many_0(one, n, twos, 0);
 263 }
 264
 265 struct commit_list *get_merge_bases(struct commit *one, struct commit *two)
 266 {
 267         return get_merge_bases_many_0(one, 1, &two, 1);
 268 }
 269
 270 /*
 271  * Is "commit" a descendant of one of the elements on the "with_commit" list?
 272  */
 273 int is_descendant_of(struct commit *commit, struct commit_list *with_commit)
 274 {
 275         if (!with_commit)
 276                 return 1;
 277         while (with_commit) {
 278                 struct commit *other;
 279
 280                 other = with_commit->item;
 281                 with_commit = with_commit->next;
 282                 if (in_merge_bases(other, commit))
 283                         return 1;
 284         }
 285         return 0;
 286 }
 287
 288 /*
 289  * Is "commit" an ancestor of one of the "references"?
 290  */
 291 int in_merge_bases_many(struct commit *commit, int nr_reference, struct commit **reference)
 292 {
 293         struct commit_list *bases;
 294         int ret = 0, i;
 295         uint32_t min_generation = GENERATION_NUMBER_INFINITY;
 296
 297         if (parse_commit(commit))
 298                 return ret;
 299         for (i = 0; i < nr_reference; i++) {
 300                 if (parse_commit(reference[i]))
 301                         return ret;
 302                 if (reference[i]->generation < min_generation)
 303                         min_generation = reference[i]->generation;
 304         }
 305
 306         if (commit->generation > min_generation)
 307                 return ret;
 308
 309         bases = paint_down_to_common(commit, nr_reference, reference, commit->generation);
 310         if (commit->object.flags & PARENT2)
 311                 ret = 1;
 312         clear_commit_marks(commit, all_flags);
 313         clear_commit_marks_many(nr_reference, reference, all_flags);
 314         free_commit_list(bases);
 315         return ret;
 316 }
 317
 318 /*
 319  * Is "commit" an ancestor of (i.e. reachable from) the "reference"?
 320  */
 321 int in_merge_bases(struct commit *commit, struct commit *reference)
 322 {
 323         return in_merge_bases_many(commit, 1, &reference);
 324 }
 325
 326 struct commit_list *reduce_heads(struct commit_list *heads)
 327 {
 328         struct commit_list *p;
 329         struct commit_list *result = NULL, **tail = &result;
 330         struct commit **array;
 331         int num_head, i;
 332
 333         if (!heads)
 334                 return NULL;
 335
 336         /* Uniquify */
 337         for (p = heads; p; p = p->next)
 338                 p->item->object.flags &= ~STALE;
 339         for (p = heads, num_head = 0; p; p = p->next) {
 340                 if (p->item->object.flags & STALE)
 341                         continue;
 342                 p->item->object.flags |= STALE;
 343                 num_head++;
 344         }
 345         array = xcalloc(num_head, sizeof(*array));
 346         for (p = heads, i = 0; p; p = p->next) {
 347                 if (p->item->object.flags & STALE) {
 348                         array[i++] = p->item;
 349                         p->item->object.flags &= ~STALE;
 350                 }
 351         }
 352         num_head = remove_redundant(array, num_head);
 353         for (i = 0; i < num_head; i++)
 354                 tail = &commit_list_insert(array[i], tail)->next;
 355         free(array);
 356         return result;
 357 }
 358
 359 void reduce_heads_replace(struct commit_list **heads)
 360 {
 361         struct commit_list *result = reduce_heads(*heads);
 362         free_commit_list(*heads);
 363         *heads = result;
 364 }
 365
 366 static void unmark_and_free(struct commit_list *list, unsigned int mark)
 367 {
 368         while (list) {
 369                 struct commit *commit = pop_commit(&list);
 370                 commit->object.flags &= ~mark;
 371         }
 372 }
 373
 374 int ref_newer(const struct object_id *new_oid, const struct object_id *old_oid)
 375 {
 376         struct object *o;
 377         struct commit *old_commit, *new_commit;
 378         struct commit_list *list, *used;
 379         int found = 0;
 380
 381         /*
 382          * Both new_commit and old_commit must be commit-ish and new_commit is descendant of
 383          * old_commit.  Otherwise we require --force.
 384          */
 385         o = deref_tag(the_repository, parse_object(the_repository, old_oid),
 386                       NULL, 0);
 387         if (!o || o->type != OBJ_COMMIT)
 388                 return 0;
 389         old_commit = (struct commit *) o;
 390
 391         o = deref_tag(the_repository, parse_object(the_repository, new_oid),
 392                       NULL, 0);
 393         if (!o || o->type != OBJ_COMMIT)
 394                 return 0;
 395         new_commit = (struct commit *) o;
 396
 397         if (parse_commit(new_commit) < 0)
 398                 return 0;
 399
 400         used = list = NULL;
 401         commit_list_insert(new_commit, &list);
 402         while (list) {
 403                 new_commit = pop_most_recent_commit(&list, TMP_MARK);
 404                 commit_list_insert(new_commit, &used);
 405                 if (new_commit == old_commit) {
 406                         found = 1;
 407                         break;
 408                 }
 409         }
 410         unmark_and_free(list, TMP_MARK);
 411         unmark_and_free(used, TMP_MARK);
 412         return found;
 413 }