Andrew's git / gitweb.git / commit.c
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commit.con commit oneway_merge(): only lstat() when told to update worktree (686b2de)
   1#include "cache.h"
   2#include "tag.h"
   3#include "commit.h"
   4#include "pkt-line.h"
   5#include "utf8.h"
   6#include "diff.h"
   7#include "revision.h"
   8#include "notes.h"
   9#include "gpg-interface.h"
  10#include "mergesort.h"
  11
  12int save_commit_buffer = 1;
  13
  14const char *commit_type = "commit";
  15
  16static struct commit *check_commit(struct object *obj,
  17                                   const unsigned char *sha1,
  18                                   int quiet)
  19{
  20        if (obj->type != OBJ_COMMIT) {
  21                if (!quiet)
  22                        error("Object %s is a %s, not a commit",
  23                              sha1_to_hex(sha1), typename(obj->type));
  24                return NULL;
  25        }
  26        return (struct commit *) obj;
  27}
  28
  29struct commit *lookup_commit_reference_gently(const unsigned char *sha1,
  30                                              int quiet)
  31{
  32        struct object *obj = deref_tag(parse_object(sha1), NULL, 0);
  33
  34        if (!obj)
  35                return NULL;
  36        return check_commit(obj, sha1, quiet);
  37}
  38
  39struct commit *lookup_commit_reference(const unsigned char *sha1)
  40{
  41        return lookup_commit_reference_gently(sha1, 0);
  42}
  43
  44struct commit *lookup_commit_or_die(const unsigned char *sha1, const char *ref_name)
  45{
  46        struct commit *c = lookup_commit_reference(sha1);
  47        if (!c)
  48                die(_("could not parse %s"), ref_name);
  49        if (hashcmp(sha1, c->object.sha1)) {
  50                warning(_("%s %s is not a commit!"),
  51                        ref_name, sha1_to_hex(sha1));
  52        }
  53        return c;
  54}
  55
  56struct commit *lookup_commit(const unsigned char *sha1)
  57{
  58        struct object *obj = lookup_object(sha1);
  59        if (!obj)
  60                return create_object(sha1, OBJ_COMMIT, alloc_commit_node());
  61        if (!obj->type)
  62                obj->type = OBJ_COMMIT;
  63        return check_commit(obj, sha1, 0);
  64}
  65
  66struct commit *lookup_commit_reference_by_name(const char *name)
  67{
  68        unsigned char sha1[20];
  69        struct commit *commit;
  70
  71        if (get_sha1_committish(name, sha1))
  72                return NULL;
  73        commit = lookup_commit_reference(sha1);
  74        if (!commit || parse_commit(commit))
  75                return NULL;
  76        return commit;
  77}
  78
  79static unsigned long parse_commit_date(const char *buf, const char *tail)
  80{
  81        const char *dateptr;
  82
  83        if (buf + 6 >= tail)
  84                return 0;
  85        if (memcmp(buf, "author", 6))
  86                return 0;
  87        while (buf < tail && *buf++ != '\n')
  88                /* nada */;
  89        if (buf + 9 >= tail)
  90                return 0;
  91        if (memcmp(buf, "committer", 9))
  92                return 0;
  93        while (buf < tail && *buf++ != '>')
  94                /* nada */;
  95        if (buf >= tail)
  96                return 0;
  97        dateptr = buf;
  98        while (buf < tail && *buf++ != '\n')
  99                /* nada */;
 100        if (buf >= tail)
 101                return 0;
 102        /* dateptr < buf && buf[-1] == '\n', so strtoul will stop at buf-1 */
 103        return strtoul(dateptr, NULL, 10);
 104}
 105
 106static struct commit_graft **commit_graft;
 107static int commit_graft_alloc, commit_graft_nr;
 108
 109static int commit_graft_pos(const unsigned char *sha1)
 110{
 111        int lo, hi;
 112        lo = 0;
 113        hi = commit_graft_nr;
 114        while (lo < hi) {
 115                int mi = (lo + hi) / 2;
 116                struct commit_graft *graft = commit_graft[mi];
 117                int cmp = hashcmp(sha1, graft->sha1);
 118                if (!cmp)
 119                        return mi;
 120                if (cmp < 0)
 121                        hi = mi;
 122                else
 123                        lo = mi + 1;
 124        }
 125        return -lo - 1;
 126}
 127
 128int register_commit_graft(struct commit_graft *graft, int ignore_dups)
 129{
 130        int pos = commit_graft_pos(graft->sha1);
 131
 132        if (0 <= pos) {
 133                if (ignore_dups)
 134                        free(graft);
 135                else {
 136                        free(commit_graft[pos]);
 137                        commit_graft[pos] = graft;
 138                }
 139                return 1;
 140        }
 141        pos = -pos - 1;
 142        if (commit_graft_alloc <= ++commit_graft_nr) {
 143                commit_graft_alloc = alloc_nr(commit_graft_alloc);
 144                commit_graft = xrealloc(commit_graft,
 145                                        sizeof(*commit_graft) *
 146                                        commit_graft_alloc);
 147        }
 148        if (pos < commit_graft_nr)
 149                memmove(commit_graft + pos + 1,
 150                        commit_graft + pos,
 151                        (commit_graft_nr - pos - 1) *
 152                        sizeof(*commit_graft));
 153        commit_graft[pos] = graft;
 154        return 0;
 155}
 156
 157struct commit_graft *read_graft_line(char *buf, int len)
 158{
 159        /* The format is just "Commit Parent1 Parent2 ...\n" */
 160        int i;
 161        struct commit_graft *graft = NULL;
 162
 163        while (len && isspace(buf[len-1]))
 164                buf[--len] = '\0';
 165        if (buf[0] == '#' || buf[0] == '\0')
 166                return NULL;
 167        if ((len + 1) % 41)
 168                goto bad_graft_data;
 169        i = (len + 1) / 41 - 1;
 170        graft = xmalloc(sizeof(*graft) + 20 * i);
 171        graft->nr_parent = i;
 172        if (get_sha1_hex(buf, graft->sha1))
 173                goto bad_graft_data;
 174        for (i = 40; i < len; i += 41) {
 175                if (buf[i] != ' ')
 176                        goto bad_graft_data;
 177                if (get_sha1_hex(buf + i + 1, graft->parent[i/41]))
 178                        goto bad_graft_data;
 179        }
 180        return graft;
 181
 182bad_graft_data:
 183        error("bad graft data: %s", buf);
 184        free(graft);
 185        return NULL;
 186}
 187
 188static int read_graft_file(const char *graft_file)
 189{
 190        FILE *fp = fopen(graft_file, "r");
 191        char buf[1024];
 192        if (!fp)
 193                return -1;
 194        while (fgets(buf, sizeof(buf), fp)) {
 195                /* The format is just "Commit Parent1 Parent2 ...\n" */
 196                int len = strlen(buf);
 197                struct commit_graft *graft = read_graft_line(buf, len);
 198                if (!graft)
 199                        continue;
 200                if (register_commit_graft(graft, 1))
 201                        error("duplicate graft data: %s", buf);
 202        }
 203        fclose(fp);
 204        return 0;
 205}
 206
 207static void prepare_commit_graft(void)
 208{
 209        static int commit_graft_prepared;
 210        char *graft_file;
 211
 212        if (commit_graft_prepared)
 213                return;
 214        graft_file = get_graft_file();
 215        read_graft_file(graft_file);
 216        /* make sure shallows are read */
 217        is_repository_shallow();
 218        commit_graft_prepared = 1;
 219}
 220
 221struct commit_graft *lookup_commit_graft(const unsigned char *sha1)
 222{
 223        int pos;
 224        prepare_commit_graft();
 225        pos = commit_graft_pos(sha1);
 226        if (pos < 0)
 227                return NULL;
 228        return commit_graft[pos];
 229}
 230
 231int for_each_commit_graft(each_commit_graft_fn fn, void *cb_data)
 232{
 233        int i, ret;
 234        for (i = ret = 0; i < commit_graft_nr && !ret; i++)
 235                ret = fn(commit_graft[i], cb_data);
 236        return ret;
 237}
 238
 239int unregister_shallow(const unsigned char *sha1)
 240{
 241        int pos = commit_graft_pos(sha1);
 242        if (pos < 0)
 243                return -1;
 244        if (pos + 1 < commit_graft_nr)
 245                memmove(commit_graft + pos, commit_graft + pos + 1,
 246                                sizeof(struct commit_graft *)
 247                                * (commit_graft_nr - pos - 1));
 248        commit_graft_nr--;
 249        return 0;
 250}
 251
 252int parse_commit_buffer(struct commit *item, const void *buffer, unsigned long size)
 253{
 254        const char *tail = buffer;
 255        const char *bufptr = buffer;
 256        unsigned char parent[20];
 257        struct commit_list **pptr;
 258        struct commit_graft *graft;
 259
 260        if (item->object.parsed)
 261                return 0;
 262        item->object.parsed = 1;
 263        tail += size;
 264        if (tail <= bufptr + 46 || memcmp(bufptr, "tree ", 5) || bufptr[45] != '\n')
 265                return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
 266        if (get_sha1_hex(bufptr + 5, parent) < 0)
 267                return error("bad tree pointer in commit %s",
 268                             sha1_to_hex(item->object.sha1));
 269        item->tree = lookup_tree(parent);
 270        bufptr += 46; /* "tree " + "hex sha1" + "\n" */
 271        pptr = &item->parents;
 272
 273        graft = lookup_commit_graft(item->object.sha1);
 274        while (bufptr + 48 < tail && !memcmp(bufptr, "parent ", 7)) {
 275                struct commit *new_parent;
 276
 277                if (tail <= bufptr + 48 ||
 278                    get_sha1_hex(bufptr + 7, parent) ||
 279                    bufptr[47] != '\n')
 280                        return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
 281                bufptr += 48;
 282                /*
 283                 * The clone is shallow if nr_parent < 0, and we must
 284                 * not traverse its real parents even when we unhide them.
 285                 */
 286                if (graft && (graft->nr_parent < 0 || grafts_replace_parents))
 287                        continue;
 288                new_parent = lookup_commit(parent);
 289                if (new_parent)
 290                        pptr = &commit_list_insert(new_parent, pptr)->next;
 291        }
 292        if (graft) {
 293                int i;
 294                struct commit *new_parent;
 295                for (i = 0; i < graft->nr_parent; i++) {
 296                        new_parent = lookup_commit(graft->parent[i]);
 297                        if (!new_parent)
 298                                continue;
 299                        pptr = &commit_list_insert(new_parent, pptr)->next;
 300                }
 301        }
 302        item->date = parse_commit_date(bufptr, tail);
 303
 304        return 0;
 305}
 306
 307int parse_commit(struct commit *item)
 308{
 309        enum object_type type;
 310        void *buffer;
 311        unsigned long size;
 312        int ret;
 313
 314        if (!item)
 315                return -1;
 316        if (item->object.parsed)
 317                return 0;
 318        buffer = read_sha1_file(item->object.sha1, &type, &size);
 319        if (!buffer)
 320                return error("Could not read %s",
 321                             sha1_to_hex(item->object.sha1));
 322        if (type != OBJ_COMMIT) {
 323                free(buffer);
 324                return error("Object %s not a commit",
 325                             sha1_to_hex(item->object.sha1));
 326        }
 327        ret = parse_commit_buffer(item, buffer, size);
 328        if (save_commit_buffer && !ret) {
 329                item->buffer = buffer;
 330                return 0;
 331        }
 332        free(buffer);
 333        return ret;
 334}
 335
 336int find_commit_subject(const char *commit_buffer, const char **subject)
 337{
 338        const char *eol;
 339        const char *p = commit_buffer;
 340
 341        while (*p && (*p != '\n' || p[1] != '\n'))
 342                p++;
 343        if (*p) {
 344                p += 2;
 345                for (eol = p; *eol && *eol != '\n'; eol++)
 346                        ; /* do nothing */
 347        } else
 348                eol = p;
 349
 350        *subject = p;
 351
 352        return eol - p;
 353}
 354
 355struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
 356{
 357        struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
 358        new_list->item = item;
 359        new_list->next = *list_p;
 360        *list_p = new_list;
 361        return new_list;
 362}
 363
 364unsigned commit_list_count(const struct commit_list *l)
 365{
 366        unsigned c = 0;
 367        for (; l; l = l->next )
 368                c++;
 369        return c;
 370}
 371
 372void free_commit_list(struct commit_list *list)
 373{
 374        while (list) {
 375                struct commit_list *temp = list;
 376                list = temp->next;
 377                free(temp);
 378        }
 379}
 380
 381struct commit_list * commit_list_insert_by_date(struct commit *item, struct commit_list **list)
 382{
 383        struct commit_list **pp = list;
 384        struct commit_list *p;
 385        while ((p = *pp) != NULL) {
 386                if (p->item->date < item->date) {
 387                        break;
 388                }
 389                pp = &p->next;
 390        }
 391        return commit_list_insert(item, pp);
 392}
 393
 394static int commit_list_compare_by_date(const void *a, const void *b)
 395{
 396        unsigned long a_date = ((const struct commit_list *)a)->item->date;
 397        unsigned long b_date = ((const struct commit_list *)b)->item->date;
 398        if (a_date < b_date)
 399                return 1;
 400        if (a_date > b_date)
 401                return -1;
 402        return 0;
 403}
 404
 405static void *commit_list_get_next(const void *a)
 406{
 407        return ((const struct commit_list *)a)->next;
 408}
 409
 410static void commit_list_set_next(void *a, void *next)
 411{
 412        ((struct commit_list *)a)->next = next;
 413}
 414
 415void commit_list_sort_by_date(struct commit_list **list)
 416{
 417        *list = llist_mergesort(*list, commit_list_get_next, commit_list_set_next,
 418                                commit_list_compare_by_date);
 419}
 420
 421struct commit *pop_most_recent_commit(struct commit_list **list,
 422                                      unsigned int mark)
 423{
 424        struct commit *ret = (*list)->item;
 425        struct commit_list *parents = ret->parents;
 426        struct commit_list *old = *list;
 427
 428        *list = (*list)->next;
 429        free(old);
 430
 431        while (parents) {
 432                struct commit *commit = parents->item;
 433                if (!parse_commit(commit) && !(commit->object.flags & mark)) {
 434                        commit->object.flags |= mark;
 435                        commit_list_insert_by_date(commit, list);
 436                }
 437                parents = parents->next;
 438        }
 439        return ret;
 440}
 441
 442static void clear_commit_marks_1(struct commit_list **plist,
 443                                 struct commit *commit, unsigned int mark)
 444{
 445        while (commit) {
 446                struct commit_list *parents;
 447
 448                if (!(mark & commit->object.flags))
 449                        return;
 450
 451                commit->object.flags &= ~mark;
 452
 453                parents = commit->parents;
 454                if (!parents)
 455                        return;
 456
 457                while ((parents = parents->next))
 458                        commit_list_insert(parents->item, plist);
 459
 460                commit = commit->parents->item;
 461        }
 462}
 463
 464void clear_commit_marks(struct commit *commit, unsigned int mark)
 465{
 466        struct commit_list *list = NULL;
 467        commit_list_insert(commit, &list);
 468        while (list)
 469                clear_commit_marks_1(&list, pop_commit(&list), mark);
 470}
 471
 472void clear_commit_marks_for_object_array(struct object_array *a, unsigned mark)
 473{
 474        struct object *object;
 475        struct commit *commit;
 476        unsigned int i;
 477
 478        for (i = 0; i < a->nr; i++) {
 479                object = a->objects[i].item;
 480                commit = lookup_commit_reference_gently(object->sha1, 1);
 481                if (commit)
 482                        clear_commit_marks(commit, mark);
 483        }
 484}
 485
 486struct commit *pop_commit(struct commit_list **stack)
 487{
 488        struct commit_list *top = *stack;
 489        struct commit *item = top ? top->item : NULL;
 490
 491        if (top) {
 492                *stack = top->next;
 493                free(top);
 494        }
 495        return item;
 496}
 497
 498/*
 499 * Performs an in-place topological sort on the list supplied.
 500 */
 501void sort_in_topological_order(struct commit_list ** list, int lifo)
 502{
 503        struct commit_list *next, *orig = *list;
 504        struct commit_list *work, **insert;
 505        struct commit_list **pptr;
 506
 507        if (!orig)
 508                return;
 509        *list = NULL;
 510
 511        /* Mark them and clear the indegree */
 512        for (next = orig; next; next = next->next) {
 513                struct commit *commit = next->item;
 514                commit->indegree = 1;
 515        }
 516
 517        /* update the indegree */
 518        for (next = orig; next; next = next->next) {
 519                struct commit_list * parents = next->item->parents;
 520                while (parents) {
 521                        struct commit *parent = parents->item;
 522
 523                        if (parent->indegree)
 524                                parent->indegree++;
 525                        parents = parents->next;
 526                }
 527        }
 528
 529        /*
 530         * find the tips
 531         *
 532         * tips are nodes not reachable from any other node in the list
 533         *
 534         * the tips serve as a starting set for the work queue.
 535         */
 536        work = NULL;
 537        insert = &work;
 538        for (next = orig; next; next = next->next) {
 539                struct commit *commit = next->item;
 540
 541                if (commit->indegree == 1)
 542                        insert = &commit_list_insert(commit, insert)->next;
 543        }
 544
 545        /* process the list in topological order */
 546        if (!lifo)
 547                commit_list_sort_by_date(&work);
 548
 549        pptr = list;
 550        *list = NULL;
 551        while (work) {
 552                struct commit *commit;
 553                struct commit_list *parents, *work_item;
 554
 555                work_item = work;
 556                work = work_item->next;
 557                work_item->next = NULL;
 558
 559                commit = work_item->item;
 560                for (parents = commit->parents; parents ; parents = parents->next) {
 561                        struct commit *parent = parents->item;
 562
 563                        if (!parent->indegree)
 564                                continue;
 565
 566                        /*
 567                         * parents are only enqueued for emission
 568                         * when all their children have been emitted thereby
 569                         * guaranteeing topological order.
 570                         */
 571                        if (--parent->indegree == 1) {
 572                                if (!lifo)
 573                                        commit_list_insert_by_date(parent, &work);
 574                                else
 575                                        commit_list_insert(parent, &work);
 576                        }
 577                }
 578                /*
 579                 * work_item is a commit all of whose children
 580                 * have already been emitted. we can emit it now.
 581                 */
 582                commit->indegree = 0;
 583                *pptr = work_item;
 584                pptr = &work_item->next;
 585        }
 586}
 587
 588/* merge-base stuff */
 589
 590/* bits #0..15 in revision.h */
 591#define PARENT1         (1u<<16)
 592#define PARENT2         (1u<<17)
 593#define STALE           (1u<<18)
 594#define RESULT          (1u<<19)
 595
 596static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
 597
 598static struct commit *interesting(struct commit_list *list)
 599{
 600        while (list) {
 601                struct commit *commit = list->item;
 602                list = list->next;
 603                if (commit->object.flags & STALE)
 604                        continue;
 605                return commit;
 606        }
 607        return NULL;
 608}
 609
 610static struct commit_list *merge_bases_many(struct commit *one, int n, struct commit **twos)
 611{
 612        struct commit_list *list = NULL;
 613        struct commit_list *result = NULL;
 614        int i;
 615
 616        for (i = 0; i < n; i++) {
 617                if (one == twos[i])
 618                        /*
 619                         * We do not mark this even with RESULT so we do not
 620                         * have to clean it up.
 621                         */
 622                        return commit_list_insert(one, &result);
 623        }
 624
 625        if (parse_commit(one))
 626                return NULL;
 627        for (i = 0; i < n; i++) {
 628                if (parse_commit(twos[i]))
 629                        return NULL;
 630        }
 631
 632        one->object.flags |= PARENT1;
 633        commit_list_insert_by_date(one, &list);
 634        for (i = 0; i < n; i++) {
 635                twos[i]->object.flags |= PARENT2;
 636                commit_list_insert_by_date(twos[i], &list);
 637        }
 638
 639        while (interesting(list)) {
 640                struct commit *commit;
 641                struct commit_list *parents;
 642                struct commit_list *next;
 643                int flags;
 644
 645                commit = list->item;
 646                next = list->next;
 647                free(list);
 648                list = next;
 649
 650                flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
 651                if (flags == (PARENT1 | PARENT2)) {
 652                        if (!(commit->object.flags & RESULT)) {
 653                                commit->object.flags |= RESULT;
 654                                commit_list_insert_by_date(commit, &result);
 655                        }
 656                        /* Mark parents of a found merge stale */
 657                        flags |= STALE;
 658                }
 659                parents = commit->parents;
 660                while (parents) {
 661                        struct commit *p = parents->item;
 662                        parents = parents->next;
 663                        if ((p->object.flags & flags) == flags)
 664                                continue;
 665                        if (parse_commit(p))
 666                                return NULL;
 667                        p->object.flags |= flags;
 668                        commit_list_insert_by_date(p, &list);
 669                }
 670        }
 671
 672        /* Clean up the result to remove stale ones */
 673        free_commit_list(list);
 674        list = result; result = NULL;
 675        while (list) {
 676                struct commit_list *next = list->next;
 677                if (!(list->item->object.flags & STALE))
 678                        commit_list_insert_by_date(list->item, &result);
 679                free(list);
 680                list = next;
 681        }
 682        return result;
 683}
 684
 685struct commit_list *get_octopus_merge_bases(struct commit_list *in)
 686{
 687        struct commit_list *i, *j, *k, *ret = NULL;
 688        struct commit_list **pptr = &ret;
 689
 690        for (i = in; i; i = i->next) {
 691                if (!ret)
 692                        pptr = &commit_list_insert(i->item, pptr)->next;
 693                else {
 694                        struct commit_list *new = NULL, *end = NULL;
 695
 696                        for (j = ret; j; j = j->next) {
 697                                struct commit_list *bases;
 698                                bases = get_merge_bases(i->item, j->item, 1);
 699                                if (!new)
 700                                        new = bases;
 701                                else
 702                                        end->next = bases;
 703                                for (k = bases; k; k = k->next)
 704                                        end = k;
 705                        }
 706                        ret = new;
 707                }
 708        }
 709        return ret;
 710}
 711
 712struct commit_list *get_merge_bases_many(struct commit *one,
 713                                         int n,
 714                                         struct commit **twos,
 715                                         int cleanup)
 716{
 717        struct commit_list *list;
 718        struct commit **rslt;
 719        struct commit_list *result;
 720        int cnt, i, j;
 721
 722        result = merge_bases_many(one, n, twos);
 723        for (i = 0; i < n; i++) {
 724                if (one == twos[i])
 725                        return result;
 726        }
 727        if (!result || !result->next) {
 728                if (cleanup) {
 729                        clear_commit_marks(one, all_flags);
 730                        for (i = 0; i < n; i++)
 731                                clear_commit_marks(twos[i], all_flags);
 732                }
 733                return result;
 734        }
 735
 736        /* There are more than one */
 737        cnt = 0;
 738        list = result;
 739        while (list) {
 740                list = list->next;
 741                cnt++;
 742        }
 743        rslt = xcalloc(cnt, sizeof(*rslt));
 744        for (list = result, i = 0; list; list = list->next)
 745                rslt[i++] = list->item;
 746        free_commit_list(result);
 747
 748        clear_commit_marks(one, all_flags);
 749        for (i = 0; i < n; i++)
 750                clear_commit_marks(twos[i], all_flags);
 751        for (i = 0; i < cnt - 1; i++) {
 752                for (j = i+1; j < cnt; j++) {
 753                        if (!rslt[i] || !rslt[j])
 754                                continue;
 755                        result = merge_bases_many(rslt[i], 1, &rslt[j]);
 756                        clear_commit_marks(rslt[i], all_flags);
 757                        clear_commit_marks(rslt[j], all_flags);
 758                        for (list = result; list; list = list->next) {
 759                                if (rslt[i] == list->item)
 760                                        rslt[i] = NULL;
 761                                if (rslt[j] == list->item)
 762                                        rslt[j] = NULL;
 763                        }
 764                }
 765        }
 766
 767        /* Surviving ones in rslt[] are the independent results */
 768        result = NULL;
 769        for (i = 0; i < cnt; i++) {
 770                if (rslt[i])
 771                        commit_list_insert_by_date(rslt[i], &result);
 772        }
 773        free(rslt);
 774        return result;
 775}
 776
 777struct commit_list *get_merge_bases(struct commit *one, struct commit *two,
 778                                    int cleanup)
 779{
 780        return get_merge_bases_many(one, 1, &two, cleanup);
 781}
 782
 783int is_descendant_of(struct commit *commit, struct commit_list *with_commit)
 784{
 785        if (!with_commit)
 786                return 1;
 787        while (with_commit) {
 788                struct commit *other;
 789
 790                other = with_commit->item;
 791                with_commit = with_commit->next;
 792                if (in_merge_bases(other, &commit, 1))
 793                        return 1;
 794        }
 795        return 0;
 796}
 797
 798int in_merge_bases(struct commit *commit, struct commit **reference, int num)
 799{
 800        struct commit_list *bases, *b;
 801        int ret = 0;
 802
 803        if (num == 1)
 804                bases = get_merge_bases(commit, *reference, 1);
 805        else
 806                die("not yet");
 807        for (b = bases; b; b = b->next) {
 808                if (!hashcmp(commit->object.sha1, b->item->object.sha1)) {
 809                        ret = 1;
 810                        break;
 811                }
 812        }
 813
 814        free_commit_list(bases);
 815        return ret;
 816}
 817
 818struct commit_list *reduce_heads(struct commit_list *heads)
 819{
 820        struct commit_list *p;
 821        struct commit_list *result = NULL, **tail = &result;
 822        struct commit **other;
 823        size_t num_head, num_other;
 824
 825        if (!heads)
 826                return NULL;
 827
 828        /* Avoid unnecessary reallocations */
 829        for (p = heads, num_head = 0; p; p = p->next)
 830                num_head++;
 831        other = xcalloc(sizeof(*other), num_head);
 832
 833        /* For each commit, see if it can be reached by others */
 834        for (p = heads; p; p = p->next) {
 835                struct commit_list *q, *base;
 836
 837                /* Do we already have this in the result? */
 838                for (q = result; q; q = q->next)
 839                        if (p->item == q->item)
 840                                break;
 841                if (q)
 842                        continue;
 843
 844                num_other = 0;
 845                for (q = heads; q; q = q->next) {
 846                        if (p->item == q->item)
 847                                continue;
 848                        other[num_other++] = q->item;
 849                }
 850                if (num_other)
 851                        base = get_merge_bases_many(p->item, num_other, other, 1);
 852                else
 853                        base = NULL;
 854                /*
 855                 * If p->item does not have anything common with other
 856                 * commits, there won't be any merge base.  If it is
 857                 * reachable from some of the others, p->item will be
 858                 * the merge base.  If its history is connected with
 859                 * others, but p->item is not reachable by others, we
 860                 * will get something other than p->item back.
 861                 */
 862                if (!base || (base->item != p->item))
 863                        tail = &(commit_list_insert(p->item, tail)->next);
 864                free_commit_list(base);
 865        }
 866        free(other);
 867        return result;
 868}
 869
 870static const char gpg_sig_header[] = "gpgsig";
 871static const int gpg_sig_header_len = sizeof(gpg_sig_header) - 1;
 872
 873static int do_sign_commit(struct strbuf *buf, const char *keyid)
 874{
 875        struct strbuf sig = STRBUF_INIT;
 876        int inspos, copypos;
 877
 878        /* find the end of the header */
 879        inspos = strstr(buf->buf, "\n\n") - buf->buf + 1;
 880
 881        if (!keyid || !*keyid)
 882                keyid = get_signing_key();
 883        if (sign_buffer(buf, &sig, keyid)) {
 884                strbuf_release(&sig);
 885                return -1;
 886        }
 887
 888        for (copypos = 0; sig.buf[copypos]; ) {
 889                const char *bol = sig.buf + copypos;
 890                const char *eol = strchrnul(bol, '\n');
 891                int len = (eol - bol) + !!*eol;
 892
 893                if (!copypos) {
 894                        strbuf_insert(buf, inspos, gpg_sig_header, gpg_sig_header_len);
 895                        inspos += gpg_sig_header_len;
 896                }
 897                strbuf_insert(buf, inspos++, " ", 1);
 898                strbuf_insert(buf, inspos, bol, len);
 899                inspos += len;
 900                copypos += len;
 901        }
 902        strbuf_release(&sig);
 903        return 0;
 904}
 905
 906int parse_signed_commit(const unsigned char *sha1,
 907                        struct strbuf *payload, struct strbuf *signature)
 908{
 909        unsigned long size;
 910        enum object_type type;
 911        char *buffer = read_sha1_file(sha1, &type, &size);
 912        int in_signature, saw_signature = -1;
 913        char *line, *tail;
 914
 915        if (!buffer || type != OBJ_COMMIT)
 916                goto cleanup;
 917
 918        line = buffer;
 919        tail = buffer + size;
 920        in_signature = 0;
 921        saw_signature = 0;
 922        while (line < tail) {
 923                const char *sig = NULL;
 924                char *next = memchr(line, '\n', tail - line);
 925
 926                next = next ? next + 1 : tail;
 927                if (in_signature && line[0] == ' ')
 928                        sig = line + 1;
 929                else if (!prefixcmp(line, gpg_sig_header) &&
 930                         line[gpg_sig_header_len] == ' ')
 931                        sig = line + gpg_sig_header_len + 1;
 932                if (sig) {
 933                        strbuf_add(signature, sig, next - sig);
 934                        saw_signature = 1;
 935                        in_signature = 1;
 936                } else {
 937                        if (*line == '\n')
 938                                /* dump the whole remainder of the buffer */
 939                                next = tail;
 940                        strbuf_add(payload, line, next - line);
 941                        in_signature = 0;
 942                }
 943                line = next;
 944        }
 945 cleanup:
 946        free(buffer);
 947        return saw_signature;
 948}
 949
 950static void handle_signed_tag(struct commit *parent, struct commit_extra_header ***tail)
 951{
 952        struct merge_remote_desc *desc;
 953        struct commit_extra_header *mergetag;
 954        char *buf;
 955        unsigned long size, len;
 956        enum object_type type;
 957
 958        desc = merge_remote_util(parent);
 959        if (!desc || !desc->obj)
 960                return;
 961        buf = read_sha1_file(desc->obj->sha1, &type, &size);
 962        if (!buf || type != OBJ_TAG)
 963                goto free_return;
 964        len = parse_signature(buf, size);
 965        if (size == len)
 966                goto free_return;
 967        /*
 968         * We could verify this signature and either omit the tag when
 969         * it does not validate, but the integrator may not have the
 970         * public key of the signer of the tag he is merging, while a
 971         * later auditor may have it while auditing, so let's not run
 972         * verify-signed-buffer here for now...
 973         *
 974         * if (verify_signed_buffer(buf, len, buf + len, size - len, ...))
 975         *      warn("warning: signed tag unverified.");
 976         */
 977        mergetag = xcalloc(1, sizeof(*mergetag));
 978        mergetag->key = xstrdup("mergetag");
 979        mergetag->value = buf;
 980        mergetag->len = size;
 981
 982        **tail = mergetag;
 983        *tail = &mergetag->next;
 984        return;
 985
 986free_return:
 987        free(buf);
 988}
 989
 990void append_merge_tag_headers(struct commit_list *parents,
 991                              struct commit_extra_header ***tail)
 992{
 993        while (parents) {
 994                struct commit *parent = parents->item;
 995                handle_signed_tag(parent, tail);
 996                parents = parents->next;
 997        }
 998}
 999
1000static void add_extra_header(struct strbuf *buffer,
1001                             struct commit_extra_header *extra)
1002{
1003        strbuf_addstr(buffer, extra->key);
1004        if (extra->len)
1005                strbuf_add_lines(buffer, " ", extra->value, extra->len);
1006        else
1007                strbuf_addch(buffer, '\n');
1008}
1009
1010struct commit_extra_header *read_commit_extra_headers(struct commit *commit,
1011                                                      const char **exclude)
1012{
1013        struct commit_extra_header *extra = NULL;
1014        unsigned long size;
1015        enum object_type type;
1016        char *buffer = read_sha1_file(commit->object.sha1, &type, &size);
1017        if (buffer && type == OBJ_COMMIT)
1018                extra = read_commit_extra_header_lines(buffer, size, exclude);
1019        free(buffer);
1020        return extra;
1021}
1022
1023static inline int standard_header_field(const char *field, size_t len)
1024{
1025        return ((len == 4 && !memcmp(field, "tree ", 5)) ||
1026                (len == 6 && !memcmp(field, "parent ", 7)) ||
1027                (len == 6 && !memcmp(field, "author ", 7)) ||
1028                (len == 9 && !memcmp(field, "committer ", 10)) ||
1029                (len == 8 && !memcmp(field, "encoding ", 9)));
1030}
1031
1032static int excluded_header_field(const char *field, size_t len, const char **exclude)
1033{
1034        if (!exclude)
1035                return 0;
1036
1037        while (*exclude) {
1038                size_t xlen = strlen(*exclude);
1039                if (len == xlen &&
1040                    !memcmp(field, *exclude, xlen) && field[xlen] == ' ')
1041                        return 1;
1042                exclude++;
1043        }
1044        return 0;
1045}
1046
1047struct commit_extra_header *read_commit_extra_header_lines(const char *buffer, size_t size,
1048                                                           const char **exclude)
1049{
1050        struct commit_extra_header *extra = NULL, **tail = &extra, *it = NULL;
1051        const char *line, *next, *eof, *eob;
1052        struct strbuf buf = STRBUF_INIT;
1053
1054        for (line = buffer, eob = line + size;
1055             line < eob && *line != '\n';
1056             line = next) {
1057                next = memchr(line, '\n', eob - line);
1058                next = next ? next + 1 : eob;
1059                if (*line == ' ') {
1060                        /* continuation */
1061                        if (it)
1062                                strbuf_add(&buf, line + 1, next - (line + 1));
1063                        continue;
1064                }
1065                if (it)
1066                        it->value = strbuf_detach(&buf, &it->len);
1067                strbuf_reset(&buf);
1068                it = NULL;
1069
1070                eof = strchr(line, ' ');
1071                if (next <= eof)
1072                        eof = next;
1073
1074                if (standard_header_field(line, eof - line) ||
1075                    excluded_header_field(line, eof - line, exclude))
1076                        continue;
1077
1078                it = xcalloc(1, sizeof(*it));
1079                it->key = xmemdupz(line, eof-line);
1080                *tail = it;
1081                tail = &it->next;
1082                if (eof + 1 < next)
1083                        strbuf_add(&buf, eof + 1, next - (eof + 1));
1084        }
1085        if (it)
1086                it->value = strbuf_detach(&buf, &it->len);
1087        return extra;
1088}
1089
1090void free_commit_extra_headers(struct commit_extra_header *extra)
1091{
1092        while (extra) {
1093                struct commit_extra_header *next = extra->next;
1094                free(extra->key);
1095                free(extra->value);
1096                free(extra);
1097                extra = next;
1098        }
1099}
1100
1101int commit_tree(const struct strbuf *msg, unsigned char *tree,
1102                struct commit_list *parents, unsigned char *ret,
1103                const char *author, const char *sign_commit)
1104{
1105        struct commit_extra_header *extra = NULL, **tail = &extra;
1106        int result;
1107
1108        append_merge_tag_headers(parents, &tail);
1109        result = commit_tree_extended(msg, tree, parents, ret,
1110                                      author, sign_commit, extra);
1111        free_commit_extra_headers(extra);
1112        return result;
1113}
1114
1115static const char commit_utf8_warn[] =
1116"Warning: commit message does not conform to UTF-8.\n"
1117"You may want to amend it after fixing the message, or set the config\n"
1118"variable i18n.commitencoding to the encoding your project uses.\n";
1119
1120int commit_tree_extended(const struct strbuf *msg, unsigned char *tree,
1121                         struct commit_list *parents, unsigned char *ret,
1122                         const char *author, const char *sign_commit,
1123                         struct commit_extra_header *extra)
1124{
1125        int result;
1126        int encoding_is_utf8;
1127        struct strbuf buffer;
1128
1129        assert_sha1_type(tree, OBJ_TREE);
1130
1131        if (memchr(msg->buf, '\0', msg->len))
1132                return error("a NUL byte in commit log message not allowed.");
1133
1134        /* Not having i18n.commitencoding is the same as having utf-8 */
1135        encoding_is_utf8 = is_encoding_utf8(git_commit_encoding);
1136
1137        strbuf_init(&buffer, 8192); /* should avoid reallocs for the headers */
1138        strbuf_addf(&buffer, "tree %s\n", sha1_to_hex(tree));
1139
1140        /*
1141         * NOTE! This ordering means that the same exact tree merged with a
1142         * different order of parents will be a _different_ changeset even
1143         * if everything else stays the same.
1144         */
1145        while (parents) {
1146                struct commit_list *next = parents->next;
1147                struct commit *parent = parents->item;
1148
1149                strbuf_addf(&buffer, "parent %s\n",
1150                            sha1_to_hex(parent->object.sha1));
1151                free(parents);
1152                parents = next;
1153        }
1154
1155        /* Person/date information */
1156        if (!author)
1157                author = git_author_info(IDENT_STRICT);
1158        strbuf_addf(&buffer, "author %s\n", author);
1159        strbuf_addf(&buffer, "committer %s\n", git_committer_info(IDENT_STRICT));
1160        if (!encoding_is_utf8)
1161                strbuf_addf(&buffer, "encoding %s\n", git_commit_encoding);
1162
1163        while (extra) {
1164                add_extra_header(&buffer, extra);
1165                extra = extra->next;
1166        }
1167        strbuf_addch(&buffer, '\n');
1168
1169        /* And add the comment */
1170        strbuf_addbuf(&buffer, msg);
1171
1172        /* And check the encoding */
1173        if (encoding_is_utf8 && !is_utf8(buffer.buf))
1174                fprintf(stderr, commit_utf8_warn);
1175
1176        if (sign_commit && do_sign_commit(&buffer, sign_commit))
1177                return -1;
1178
1179        result = write_sha1_file(buffer.buf, buffer.len, commit_type, ret);
1180        strbuf_release(&buffer);
1181        return result;
1182}
1183
1184struct commit *get_merge_parent(const char *name)
1185{
1186        struct object *obj;
1187        struct commit *commit;
1188        unsigned char sha1[20];
1189        if (get_sha1(name, sha1))
1190                return NULL;
1191        obj = parse_object(sha1);
1192        commit = (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
1193        if (commit && !commit->util) {
1194                struct merge_remote_desc *desc;
1195                desc = xmalloc(sizeof(*desc));
1196                desc->obj = obj;
1197                desc->name = strdup(name);
1198                commit->util = desc;
1199        }
1200        return commit;
1201}
1202
1203/*
1204 * Append a commit to the end of the commit_list.
1205 *
1206 * next starts by pointing to the variable that holds the head of an
1207 * empty commit_list, and is updated to point to the "next" field of
1208 * the last item on the list as new commits are appended.
1209 *
1210 * Usage example:
1211 *
1212 *     struct commit_list *list;
1213 *     struct commit_list **next = &list;
1214 *
1215 *     next = commit_list_append(c1, next);
1216 *     next = commit_list_append(c2, next);
1217 *     assert(commit_list_count(list) == 2);
1218 *     return list;
1219 */
1220struct commit_list **commit_list_append(struct commit *commit,
1221                                        struct commit_list **next)
1222{
1223        struct commit_list *new = xmalloc(sizeof(struct commit_list));
1224        new->item = commit;
1225        *next = new;
1226        new->next = NULL;
1227        return &new->next;
1228}