git.oblomov.eu Git - git/blob - commit-reach.c

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