Andrew's git / gitweb.git / commit.c
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commit.con commit Makefile: drop dependency between git-instaweb and gitweb (e25c7cc)
   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#include "commit-slab.h"
  12#include "prio-queue.h"
  13#include "sha1-lookup.h"
  14
  15static struct commit_extra_header *read_commit_extra_header_lines(const char *buf, size_t len, const char **);
  16
  17int save_commit_buffer = 1;
  18
  19const char *commit_type = "commit";
  20
  21struct commit *lookup_commit_reference_gently(const unsigned char *sha1,
  22                                              int quiet)
  23{
  24        struct object *obj = deref_tag(parse_object(sha1), NULL, 0);
  25
  26        if (!obj)
  27                return NULL;
  28        return object_as_type(obj, OBJ_COMMIT, quiet);
  29}
  30
  31struct commit *lookup_commit_reference(const unsigned char *sha1)
  32{
  33        return lookup_commit_reference_gently(sha1, 0);
  34}
  35
  36struct commit *lookup_commit_or_die(const unsigned char *sha1, const char *ref_name)
  37{
  38        struct commit *c = lookup_commit_reference(sha1);
  39        if (!c)
  40                die(_("could not parse %s"), ref_name);
  41        if (hashcmp(sha1, c->object.sha1)) {
  42                warning(_("%s %s is not a commit!"),
  43                        ref_name, sha1_to_hex(sha1));
  44        }
  45        return c;
  46}
  47
  48struct commit *lookup_commit(const unsigned char *sha1)
  49{
  50        struct object *obj = lookup_object(sha1);
  51        if (!obj)
  52                return create_object(sha1, alloc_commit_node());
  53        return object_as_type(obj, OBJ_COMMIT, 0);
  54}
  55
  56struct commit *lookup_commit_reference_by_name(const char *name)
  57{
  58        unsigned char sha1[20];
  59        struct commit *commit;
  60
  61        if (get_sha1_committish(name, sha1))
  62                return NULL;
  63        commit = lookup_commit_reference(sha1);
  64        if (parse_commit(commit))
  65                return NULL;
  66        return commit;
  67}
  68
  69static unsigned long parse_commit_date(const char *buf, const char *tail)
  70{
  71        const char *dateptr;
  72
  73        if (buf + 6 >= tail)
  74                return 0;
  75        if (memcmp(buf, "author", 6))
  76                return 0;
  77        while (buf < tail && *buf++ != '\n')
  78                /* nada */;
  79        if (buf + 9 >= tail)
  80                return 0;
  81        if (memcmp(buf, "committer", 9))
  82                return 0;
  83        while (buf < tail && *buf++ != '>')
  84                /* nada */;
  85        if (buf >= tail)
  86                return 0;
  87        dateptr = buf;
  88        while (buf < tail && *buf++ != '\n')
  89                /* nada */;
  90        if (buf >= tail)
  91                return 0;
  92        /* dateptr < buf && buf[-1] == '\n', so strtoul will stop at buf-1 */
  93        return strtoul(dateptr, NULL, 10);
  94}
  95
  96static struct commit_graft **commit_graft;
  97static int commit_graft_alloc, commit_graft_nr;
  98
  99static const unsigned char *commit_graft_sha1_access(size_t index, void *table)
 100{
 101        struct commit_graft **commit_graft_table = table;
 102        return commit_graft_table[index]->sha1;
 103}
 104
 105static int commit_graft_pos(const unsigned char *sha1)
 106{
 107        return sha1_pos(sha1, commit_graft, commit_graft_nr,
 108                        commit_graft_sha1_access);
 109}
 110
 111int register_commit_graft(struct commit_graft *graft, int ignore_dups)
 112{
 113        int pos = commit_graft_pos(graft->sha1);
 114
 115        if (0 <= pos) {
 116                if (ignore_dups)
 117                        free(graft);
 118                else {
 119                        free(commit_graft[pos]);
 120                        commit_graft[pos] = graft;
 121                }
 122                return 1;
 123        }
 124        pos = -pos - 1;
 125        ALLOC_GROW(commit_graft, commit_graft_nr + 1, commit_graft_alloc);
 126        commit_graft_nr++;
 127        if (pos < commit_graft_nr)
 128                memmove(commit_graft + pos + 1,
 129                        commit_graft + pos,
 130                        (commit_graft_nr - pos - 1) *
 131                        sizeof(*commit_graft));
 132        commit_graft[pos] = graft;
 133        return 0;
 134}
 135
 136struct commit_graft *read_graft_line(char *buf, int len)
 137{
 138        /* The format is just "Commit Parent1 Parent2 ...\n" */
 139        int i;
 140        struct commit_graft *graft = NULL;
 141
 142        while (len && isspace(buf[len-1]))
 143                buf[--len] = '\0';
 144        if (buf[0] == '#' || buf[0] == '\0')
 145                return NULL;
 146        if ((len + 1) % 41)
 147                goto bad_graft_data;
 148        i = (len + 1) / 41 - 1;
 149        graft = xmalloc(sizeof(*graft) + 20 * i);
 150        graft->nr_parent = i;
 151        if (get_sha1_hex(buf, graft->sha1))
 152                goto bad_graft_data;
 153        for (i = 40; i < len; i += 41) {
 154                if (buf[i] != ' ')
 155                        goto bad_graft_data;
 156                if (get_sha1_hex(buf + i + 1, graft->parent[i/41]))
 157                        goto bad_graft_data;
 158        }
 159        return graft;
 160
 161bad_graft_data:
 162        error("bad graft data: %s", buf);
 163        free(graft);
 164        return NULL;
 165}
 166
 167static int read_graft_file(const char *graft_file)
 168{
 169        FILE *fp = fopen(graft_file, "r");
 170        struct strbuf buf = STRBUF_INIT;
 171        if (!fp)
 172                return -1;
 173        while (!strbuf_getwholeline(&buf, fp, '\n')) {
 174                /* The format is just "Commit Parent1 Parent2 ...\n" */
 175                struct commit_graft *graft = read_graft_line(buf.buf, buf.len);
 176                if (!graft)
 177                        continue;
 178                if (register_commit_graft(graft, 1))
 179                        error("duplicate graft data: %s", buf.buf);
 180        }
 181        fclose(fp);
 182        strbuf_release(&buf);
 183        return 0;
 184}
 185
 186static void prepare_commit_graft(void)
 187{
 188        static int commit_graft_prepared;
 189        char *graft_file;
 190
 191        if (commit_graft_prepared)
 192                return;
 193        graft_file = get_graft_file();
 194        read_graft_file(graft_file);
 195        /* make sure shallows are read */
 196        is_repository_shallow();
 197        commit_graft_prepared = 1;
 198}
 199
 200struct commit_graft *lookup_commit_graft(const unsigned char *sha1)
 201{
 202        int pos;
 203        prepare_commit_graft();
 204        pos = commit_graft_pos(sha1);
 205        if (pos < 0)
 206                return NULL;
 207        return commit_graft[pos];
 208}
 209
 210int for_each_commit_graft(each_commit_graft_fn fn, void *cb_data)
 211{
 212        int i, ret;
 213        for (i = ret = 0; i < commit_graft_nr && !ret; i++)
 214                ret = fn(commit_graft[i], cb_data);
 215        return ret;
 216}
 217
 218int unregister_shallow(const unsigned char *sha1)
 219{
 220        int pos = commit_graft_pos(sha1);
 221        if (pos < 0)
 222                return -1;
 223        if (pos + 1 < commit_graft_nr)
 224                memmove(commit_graft + pos, commit_graft + pos + 1,
 225                                sizeof(struct commit_graft *)
 226                                * (commit_graft_nr - pos - 1));
 227        commit_graft_nr--;
 228        return 0;
 229}
 230
 231struct commit_buffer {
 232        void *buffer;
 233        unsigned long size;
 234};
 235define_commit_slab(buffer_slab, struct commit_buffer);
 236static struct buffer_slab buffer_slab = COMMIT_SLAB_INIT(1, buffer_slab);
 237
 238void set_commit_buffer(struct commit *commit, void *buffer, unsigned long size)
 239{
 240        struct commit_buffer *v = buffer_slab_at(&buffer_slab, commit);
 241        v->buffer = buffer;
 242        v->size = size;
 243}
 244
 245const void *get_cached_commit_buffer(const struct commit *commit, unsigned long *sizep)
 246{
 247        struct commit_buffer *v = buffer_slab_at(&buffer_slab, commit);
 248        if (sizep)
 249                *sizep = v->size;
 250        return v->buffer;
 251}
 252
 253const void *get_commit_buffer(const struct commit *commit, unsigned long *sizep)
 254{
 255        const void *ret = get_cached_commit_buffer(commit, sizep);
 256        if (!ret) {
 257                enum object_type type;
 258                unsigned long size;
 259                ret = read_sha1_file(commit->object.sha1, &type, &size);
 260                if (!ret)
 261                        die("cannot read commit object %s",
 262                            sha1_to_hex(commit->object.sha1));
 263                if (type != OBJ_COMMIT)
 264                        die("expected commit for %s, got %s",
 265                            sha1_to_hex(commit->object.sha1), typename(type));
 266                if (sizep)
 267                        *sizep = size;
 268        }
 269        return ret;
 270}
 271
 272void unuse_commit_buffer(const struct commit *commit, const void *buffer)
 273{
 274        struct commit_buffer *v = buffer_slab_at(&buffer_slab, commit);
 275        if (v->buffer != buffer)
 276                free((void *)buffer);
 277}
 278
 279void free_commit_buffer(struct commit *commit)
 280{
 281        struct commit_buffer *v = buffer_slab_at(&buffer_slab, commit);
 282        free(v->buffer);
 283        v->buffer = NULL;
 284        v->size = 0;
 285}
 286
 287const void *detach_commit_buffer(struct commit *commit, unsigned long *sizep)
 288{
 289        struct commit_buffer *v = buffer_slab_at(&buffer_slab, commit);
 290        void *ret;
 291
 292        ret = v->buffer;
 293        if (sizep)
 294                *sizep = v->size;
 295
 296        v->buffer = NULL;
 297        v->size = 0;
 298        return ret;
 299}
 300
 301int parse_commit_buffer(struct commit *item, const void *buffer, unsigned long size)
 302{
 303        const char *tail = buffer;
 304        const char *bufptr = buffer;
 305        unsigned char parent[20];
 306        struct commit_list **pptr;
 307        struct commit_graft *graft;
 308
 309        if (item->object.parsed)
 310                return 0;
 311        item->object.parsed = 1;
 312        tail += size;
 313        if (tail <= bufptr + 46 || memcmp(bufptr, "tree ", 5) || bufptr[45] != '\n')
 314                return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
 315        if (get_sha1_hex(bufptr + 5, parent) < 0)
 316                return error("bad tree pointer in commit %s",
 317                             sha1_to_hex(item->object.sha1));
 318        item->tree = lookup_tree(parent);
 319        bufptr += 46; /* "tree " + "hex sha1" + "\n" */
 320        pptr = &item->parents;
 321
 322        graft = lookup_commit_graft(item->object.sha1);
 323        while (bufptr + 48 < tail && !memcmp(bufptr, "parent ", 7)) {
 324                struct commit *new_parent;
 325
 326                if (tail <= bufptr + 48 ||
 327                    get_sha1_hex(bufptr + 7, parent) ||
 328                    bufptr[47] != '\n')
 329                        return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
 330                bufptr += 48;
 331                /*
 332                 * The clone is shallow if nr_parent < 0, and we must
 333                 * not traverse its real parents even when we unhide them.
 334                 */
 335                if (graft && (graft->nr_parent < 0 || grafts_replace_parents))
 336                        continue;
 337                new_parent = lookup_commit(parent);
 338                if (new_parent)
 339                        pptr = &commit_list_insert(new_parent, pptr)->next;
 340        }
 341        if (graft) {
 342                int i;
 343                struct commit *new_parent;
 344                for (i = 0; i < graft->nr_parent; i++) {
 345                        new_parent = lookup_commit(graft->parent[i]);
 346                        if (!new_parent)
 347                                continue;
 348                        pptr = &commit_list_insert(new_parent, pptr)->next;
 349                }
 350        }
 351        item->date = parse_commit_date(bufptr, tail);
 352
 353        return 0;
 354}
 355
 356int parse_commit(struct commit *item)
 357{
 358        enum object_type type;
 359        void *buffer;
 360        unsigned long size;
 361        int ret;
 362
 363        if (!item)
 364                return -1;
 365        if (item->object.parsed)
 366                return 0;
 367        buffer = read_sha1_file(item->object.sha1, &type, &size);
 368        if (!buffer)
 369                return error("Could not read %s",
 370                             sha1_to_hex(item->object.sha1));
 371        if (type != OBJ_COMMIT) {
 372                free(buffer);
 373                return error("Object %s not a commit",
 374                             sha1_to_hex(item->object.sha1));
 375        }
 376        ret = parse_commit_buffer(item, buffer, size);
 377        if (save_commit_buffer && !ret) {
 378                set_commit_buffer(item, buffer, size);
 379                return 0;
 380        }
 381        free(buffer);
 382        return ret;
 383}
 384
 385void parse_commit_or_die(struct commit *item)
 386{
 387        if (parse_commit(item))
 388                die("unable to parse commit %s",
 389                    item ? sha1_to_hex(item->object.sha1) : "(null)");
 390}
 391
 392int find_commit_subject(const char *commit_buffer, const char **subject)
 393{
 394        const char *eol;
 395        const char *p = commit_buffer;
 396
 397        while (*p && (*p != '\n' || p[1] != '\n'))
 398                p++;
 399        if (*p) {
 400                p += 2;
 401                for (eol = p; *eol && *eol != '\n'; eol++)
 402                        ; /* do nothing */
 403        } else
 404                eol = p;
 405
 406        *subject = p;
 407
 408        return eol - p;
 409}
 410
 411struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
 412{
 413        struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
 414        new_list->item = item;
 415        new_list->next = *list_p;
 416        *list_p = new_list;
 417        return new_list;
 418}
 419
 420unsigned commit_list_count(const struct commit_list *l)
 421{
 422        unsigned c = 0;
 423        for (; l; l = l->next )
 424                c++;
 425        return c;
 426}
 427
 428struct commit_list *copy_commit_list(struct commit_list *list)
 429{
 430        struct commit_list *head = NULL;
 431        struct commit_list **pp = &head;
 432        while (list) {
 433                pp = commit_list_append(list->item, pp);
 434                list = list->next;
 435        }
 436        return head;
 437}
 438
 439void free_commit_list(struct commit_list *list)
 440{
 441        while (list) {
 442                struct commit_list *temp = list;
 443                list = temp->next;
 444                free(temp);
 445        }
 446}
 447
 448struct commit_list * commit_list_insert_by_date(struct commit *item, struct commit_list **list)
 449{
 450        struct commit_list **pp = list;
 451        struct commit_list *p;
 452        while ((p = *pp) != NULL) {
 453                if (p->item->date < item->date) {
 454                        break;
 455                }
 456                pp = &p->next;
 457        }
 458        return commit_list_insert(item, pp);
 459}
 460
 461static int commit_list_compare_by_date(const void *a, const void *b)
 462{
 463        unsigned long a_date = ((const struct commit_list *)a)->item->date;
 464        unsigned long b_date = ((const struct commit_list *)b)->item->date;
 465        if (a_date < b_date)
 466                return 1;
 467        if (a_date > b_date)
 468                return -1;
 469        return 0;
 470}
 471
 472static void *commit_list_get_next(const void *a)
 473{
 474        return ((const struct commit_list *)a)->next;
 475}
 476
 477static void commit_list_set_next(void *a, void *next)
 478{
 479        ((struct commit_list *)a)->next = next;
 480}
 481
 482void commit_list_sort_by_date(struct commit_list **list)
 483{
 484        *list = llist_mergesort(*list, commit_list_get_next, commit_list_set_next,
 485                                commit_list_compare_by_date);
 486}
 487
 488struct commit *pop_most_recent_commit(struct commit_list **list,
 489                                      unsigned int mark)
 490{
 491        struct commit *ret = (*list)->item;
 492        struct commit_list *parents = ret->parents;
 493        struct commit_list *old = *list;
 494
 495        *list = (*list)->next;
 496        free(old);
 497
 498        while (parents) {
 499                struct commit *commit = parents->item;
 500                if (!parse_commit(commit) && !(commit->object.flags & mark)) {
 501                        commit->object.flags |= mark;
 502                        commit_list_insert_by_date(commit, list);
 503                }
 504                parents = parents->next;
 505        }
 506        return ret;
 507}
 508
 509static void clear_commit_marks_1(struct commit_list **plist,
 510                                 struct commit *commit, unsigned int mark)
 511{
 512        while (commit) {
 513                struct commit_list *parents;
 514
 515                if (!(mark & commit->object.flags))
 516                        return;
 517
 518                commit->object.flags &= ~mark;
 519
 520                parents = commit->parents;
 521                if (!parents)
 522                        return;
 523
 524                while ((parents = parents->next))
 525                        commit_list_insert(parents->item, plist);
 526
 527                commit = commit->parents->item;
 528        }
 529}
 530
 531void clear_commit_marks_many(int nr, struct commit **commit, unsigned int mark)
 532{
 533        struct commit_list *list = NULL;
 534
 535        while (nr--) {
 536                commit_list_insert(*commit, &list);
 537                commit++;
 538        }
 539        while (list)
 540                clear_commit_marks_1(&list, pop_commit(&list), mark);
 541}
 542
 543void clear_commit_marks(struct commit *commit, unsigned int mark)
 544{
 545        clear_commit_marks_many(1, &commit, mark);
 546}
 547
 548void clear_commit_marks_for_object_array(struct object_array *a, unsigned mark)
 549{
 550        struct object *object;
 551        struct commit *commit;
 552        unsigned int i;
 553
 554        for (i = 0; i < a->nr; i++) {
 555                object = a->objects[i].item;
 556                commit = lookup_commit_reference_gently(object->sha1, 1);
 557                if (commit)
 558                        clear_commit_marks(commit, mark);
 559        }
 560}
 561
 562struct commit *pop_commit(struct commit_list **stack)
 563{
 564        struct commit_list *top = *stack;
 565        struct commit *item = top ? top->item : NULL;
 566
 567        if (top) {
 568                *stack = top->next;
 569                free(top);
 570        }
 571        return item;
 572}
 573
 574/*
 575 * Topological sort support
 576 */
 577
 578/* count number of children that have not been emitted */
 579define_commit_slab(indegree_slab, int);
 580
 581/* record author-date for each commit object */
 582define_commit_slab(author_date_slab, unsigned long);
 583
 584static void record_author_date(struct author_date_slab *author_date,
 585                               struct commit *commit)
 586{
 587        const char *buffer = get_commit_buffer(commit, NULL);
 588        struct ident_split ident;
 589        const char *ident_line;
 590        size_t ident_len;
 591        char *date_end;
 592        unsigned long date;
 593
 594        ident_line = find_commit_header(buffer, "author", &ident_len);
 595        if (!ident_line)
 596                goto fail_exit; /* no author line */
 597        if (split_ident_line(&ident, ident_line, ident_len) ||
 598            !ident.date_begin || !ident.date_end)
 599                goto fail_exit; /* malformed "author" line */
 600
 601        date = strtoul(ident.date_begin, &date_end, 10);
 602        if (date_end != ident.date_end)
 603                goto fail_exit; /* malformed date */
 604        *(author_date_slab_at(author_date, commit)) = date;
 605
 606fail_exit:
 607        unuse_commit_buffer(commit, buffer);
 608}
 609
 610static int compare_commits_by_author_date(const void *a_, const void *b_,
 611                                          void *cb_data)
 612{
 613        const struct commit *a = a_, *b = b_;
 614        struct author_date_slab *author_date = cb_data;
 615        unsigned long a_date = *(author_date_slab_at(author_date, a));
 616        unsigned long b_date = *(author_date_slab_at(author_date, b));
 617
 618        /* newer commits with larger date first */
 619        if (a_date < b_date)
 620                return 1;
 621        else if (a_date > b_date)
 622                return -1;
 623        return 0;
 624}
 625
 626int compare_commits_by_commit_date(const void *a_, const void *b_, void *unused)
 627{
 628        const struct commit *a = a_, *b = b_;
 629        /* newer commits with larger date first */
 630        if (a->date < b->date)
 631                return 1;
 632        else if (a->date > b->date)
 633                return -1;
 634        return 0;
 635}
 636
 637/*
 638 * Performs an in-place topological sort on the list supplied.
 639 */
 640void sort_in_topological_order(struct commit_list **list, enum rev_sort_order sort_order)
 641{
 642        struct commit_list *next, *orig = *list;
 643        struct commit_list **pptr;
 644        struct indegree_slab indegree;
 645        struct prio_queue queue;
 646        struct commit *commit;
 647        struct author_date_slab author_date;
 648
 649        if (!orig)
 650                return;
 651        *list = NULL;
 652
 653        init_indegree_slab(&indegree);
 654        memset(&queue, '\0', sizeof(queue));
 655
 656        switch (sort_order) {
 657        default: /* REV_SORT_IN_GRAPH_ORDER */
 658                queue.compare = NULL;
 659                break;
 660        case REV_SORT_BY_COMMIT_DATE:
 661                queue.compare = compare_commits_by_commit_date;
 662                break;
 663        case REV_SORT_BY_AUTHOR_DATE:
 664                init_author_date_slab(&author_date);
 665                queue.compare = compare_commits_by_author_date;
 666                queue.cb_data = &author_date;
 667                break;
 668        }
 669
 670        /* Mark them and clear the indegree */
 671        for (next = orig; next; next = next->next) {
 672                struct commit *commit = next->item;
 673                *(indegree_slab_at(&indegree, commit)) = 1;
 674                /* also record the author dates, if needed */
 675                if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 676                        record_author_date(&author_date, commit);
 677        }
 678
 679        /* update the indegree */
 680        for (next = orig; next; next = next->next) {
 681                struct commit_list *parents = next->item->parents;
 682                while (parents) {
 683                        struct commit *parent = parents->item;
 684                        int *pi = indegree_slab_at(&indegree, parent);
 685
 686                        if (*pi)
 687                                (*pi)++;
 688                        parents = parents->next;
 689                }
 690        }
 691
 692        /*
 693         * find the tips
 694         *
 695         * tips are nodes not reachable from any other node in the list
 696         *
 697         * the tips serve as a starting set for the work queue.
 698         */
 699        for (next = orig; next; next = next->next) {
 700                struct commit *commit = next->item;
 701
 702                if (*(indegree_slab_at(&indegree, commit)) == 1)
 703                        prio_queue_put(&queue, commit);
 704        }
 705
 706        /*
 707         * This is unfortunate; the initial tips need to be shown
 708         * in the order given from the revision traversal machinery.
 709         */
 710        if (sort_order == REV_SORT_IN_GRAPH_ORDER)
 711                prio_queue_reverse(&queue);
 712
 713        /* We no longer need the commit list */
 714        free_commit_list(orig);
 715
 716        pptr = list;
 717        *list = NULL;
 718        while ((commit = prio_queue_get(&queue)) != NULL) {
 719                struct commit_list *parents;
 720
 721                for (parents = commit->parents; parents ; parents = parents->next) {
 722                        struct commit *parent = parents->item;
 723                        int *pi = indegree_slab_at(&indegree, parent);
 724
 725                        if (!*pi)
 726                                continue;
 727
 728                        /*
 729                         * parents are only enqueued for emission
 730                         * when all their children have been emitted thereby
 731                         * guaranteeing topological order.
 732                         */
 733                        if (--(*pi) == 1)
 734                                prio_queue_put(&queue, parent);
 735                }
 736                /*
 737                 * all children of commit have already been
 738                 * emitted. we can emit it now.
 739                 */
 740                *(indegree_slab_at(&indegree, commit)) = 0;
 741
 742                pptr = &commit_list_insert(commit, pptr)->next;
 743        }
 744
 745        clear_indegree_slab(&indegree);
 746        clear_prio_queue(&queue);
 747        if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 748                clear_author_date_slab(&author_date);
 749}
 750
 751/* merge-base stuff */
 752
 753/* Remember to update object flag allocation in object.h */
 754#define PARENT1         (1u<<16)
 755#define PARENT2         (1u<<17)
 756#define STALE           (1u<<18)
 757#define RESULT          (1u<<19)
 758
 759static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
 760
 761static int queue_has_nonstale(struct prio_queue *queue)
 762{
 763        int i;
 764        for (i = 0; i < queue->nr; i++) {
 765                struct commit *commit = queue->array[i].data;
 766                if (!(commit->object.flags & STALE))
 767                        return 1;
 768        }
 769        return 0;
 770}
 771
 772/* all input commits in one and twos[] must have been parsed! */
 773static struct commit_list *paint_down_to_common(struct commit *one, int n, struct commit **twos)
 774{
 775        struct prio_queue queue = { compare_commits_by_commit_date };
 776        struct commit_list *result = NULL;
 777        int i;
 778
 779        one->object.flags |= PARENT1;
 780        if (!n) {
 781                commit_list_append(one, &result);
 782                return result;
 783        }
 784        prio_queue_put(&queue, one);
 785
 786        for (i = 0; i < n; i++) {
 787                twos[i]->object.flags |= PARENT2;
 788                prio_queue_put(&queue, twos[i]);
 789        }
 790
 791        while (queue_has_nonstale(&queue)) {
 792                struct commit *commit = prio_queue_get(&queue);
 793                struct commit_list *parents;
 794                int flags;
 795
 796                flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
 797                if (flags == (PARENT1 | PARENT2)) {
 798                        if (!(commit->object.flags & RESULT)) {
 799                                commit->object.flags |= RESULT;
 800                                commit_list_insert_by_date(commit, &result);
 801                        }
 802                        /* Mark parents of a found merge stale */
 803                        flags |= STALE;
 804                }
 805                parents = commit->parents;
 806                while (parents) {
 807                        struct commit *p = parents->item;
 808                        parents = parents->next;
 809                        if ((p->object.flags & flags) == flags)
 810                                continue;
 811                        if (parse_commit(p))
 812                                return NULL;
 813                        p->object.flags |= flags;
 814                        prio_queue_put(&queue, p);
 815                }
 816        }
 817
 818        clear_prio_queue(&queue);
 819        return result;
 820}
 821
 822static struct commit_list *merge_bases_many(struct commit *one, int n, struct commit **twos)
 823{
 824        struct commit_list *list = NULL;
 825        struct commit_list *result = NULL;
 826        int i;
 827
 828        for (i = 0; i < n; i++) {
 829                if (one == twos[i])
 830                        /*
 831                         * We do not mark this even with RESULT so we do not
 832                         * have to clean it up.
 833                         */
 834                        return commit_list_insert(one, &result);
 835        }
 836
 837        if (parse_commit(one))
 838                return NULL;
 839        for (i = 0; i < n; i++) {
 840                if (parse_commit(twos[i]))
 841                        return NULL;
 842        }
 843
 844        list = paint_down_to_common(one, n, twos);
 845
 846        while (list) {
 847                struct commit_list *next = list->next;
 848                if (!(list->item->object.flags & STALE))
 849                        commit_list_insert_by_date(list->item, &result);
 850                free(list);
 851                list = next;
 852        }
 853        return result;
 854}
 855
 856struct commit_list *get_octopus_merge_bases(struct commit_list *in)
 857{
 858        struct commit_list *i, *j, *k, *ret = NULL;
 859
 860        if (!in)
 861                return ret;
 862
 863        commit_list_insert(in->item, &ret);
 864
 865        for (i = in->next; i; i = i->next) {
 866                struct commit_list *new = NULL, *end = NULL;
 867
 868                for (j = ret; j; j = j->next) {
 869                        struct commit_list *bases;
 870                        bases = get_merge_bases(i->item, j->item, 1);
 871                        if (!new)
 872                                new = bases;
 873                        else
 874                                end->next = bases;
 875                        for (k = bases; k; k = k->next)
 876                                end = k;
 877                }
 878                ret = new;
 879        }
 880        return ret;
 881}
 882
 883static int remove_redundant(struct commit **array, int cnt)
 884{
 885        /*
 886         * Some commit in the array may be an ancestor of
 887         * another commit.  Move such commit to the end of
 888         * the array, and return the number of commits that
 889         * are independent from each other.
 890         */
 891        struct commit **work;
 892        unsigned char *redundant;
 893        int *filled_index;
 894        int i, j, filled;
 895
 896        work = xcalloc(cnt, sizeof(*work));
 897        redundant = xcalloc(cnt, 1);
 898        filled_index = xmalloc(sizeof(*filled_index) * (cnt - 1));
 899
 900        for (i = 0; i < cnt; i++)
 901                parse_commit(array[i]);
 902        for (i = 0; i < cnt; i++) {
 903                struct commit_list *common;
 904
 905                if (redundant[i])
 906                        continue;
 907                for (j = filled = 0; j < cnt; j++) {
 908                        if (i == j || redundant[j])
 909                                continue;
 910                        filled_index[filled] = j;
 911                        work[filled++] = array[j];
 912                }
 913                common = paint_down_to_common(array[i], filled, work);
 914                if (array[i]->object.flags & PARENT2)
 915                        redundant[i] = 1;
 916                for (j = 0; j < filled; j++)
 917                        if (work[j]->object.flags & PARENT1)
 918                                redundant[filled_index[j]] = 1;
 919                clear_commit_marks(array[i], all_flags);
 920                for (j = 0; j < filled; j++)
 921                        clear_commit_marks(work[j], all_flags);
 922                free_commit_list(common);
 923        }
 924
 925        /* Now collect the result */
 926        memcpy(work, array, sizeof(*array) * cnt);
 927        for (i = filled = 0; i < cnt; i++)
 928                if (!redundant[i])
 929                        array[filled++] = work[i];
 930        for (j = filled, i = 0; i < cnt; i++)
 931                if (redundant[i])
 932                        array[j++] = work[i];
 933        free(work);
 934        free(redundant);
 935        free(filled_index);
 936        return filled;
 937}
 938
 939struct commit_list *get_merge_bases_many(struct commit *one,
 940                                         int n,
 941                                         struct commit **twos,
 942                                         int cleanup)
 943{
 944        struct commit_list *list;
 945        struct commit **rslt;
 946        struct commit_list *result;
 947        int cnt, i;
 948
 949        result = merge_bases_many(one, n, twos);
 950        for (i = 0; i < n; i++) {
 951                if (one == twos[i])
 952                        return result;
 953        }
 954        if (!result || !result->next) {
 955                if (cleanup) {
 956                        clear_commit_marks(one, all_flags);
 957                        clear_commit_marks_many(n, twos, all_flags);
 958                }
 959                return result;
 960        }
 961
 962        /* There are more than one */
 963        cnt = commit_list_count(result);
 964        rslt = xcalloc(cnt, sizeof(*rslt));
 965        for (list = result, i = 0; list; list = list->next)
 966                rslt[i++] = list->item;
 967        free_commit_list(result);
 968
 969        clear_commit_marks(one, all_flags);
 970        clear_commit_marks_many(n, twos, all_flags);
 971
 972        cnt = remove_redundant(rslt, cnt);
 973        result = NULL;
 974        for (i = 0; i < cnt; i++)
 975                commit_list_insert_by_date(rslt[i], &result);
 976        free(rslt);
 977        return result;
 978}
 979
 980struct commit_list *get_merge_bases(struct commit *one, struct commit *two,
 981                                    int cleanup)
 982{
 983        return get_merge_bases_many(one, 1, &two, cleanup);
 984}
 985
 986/*
 987 * Is "commit" a descendant of one of the elements on the "with_commit" list?
 988 */
 989int is_descendant_of(struct commit *commit, struct commit_list *with_commit)
 990{
 991        if (!with_commit)
 992                return 1;
 993        while (with_commit) {
 994                struct commit *other;
 995
 996                other = with_commit->item;
 997                with_commit = with_commit->next;
 998                if (in_merge_bases(other, commit))
 999                        return 1;
1000        }
1001        return 0;
1002}
1003
1004/*
1005 * Is "commit" an ancestor of one of the "references"?
1006 */
1007int in_merge_bases_many(struct commit *commit, int nr_reference, struct commit **reference)
1008{
1009        struct commit_list *bases;
1010        int ret = 0, i;
1011
1012        if (parse_commit(commit))
1013                return ret;
1014        for (i = 0; i < nr_reference; i++)
1015                if (parse_commit(reference[i]))
1016                        return ret;
1017
1018        bases = paint_down_to_common(commit, nr_reference, reference);
1019        if (commit->object.flags & PARENT2)
1020                ret = 1;
1021        clear_commit_marks(commit, all_flags);
1022        clear_commit_marks_many(nr_reference, reference, all_flags);
1023        free_commit_list(bases);
1024        return ret;
1025}
1026
1027/*
1028 * Is "commit" an ancestor of (i.e. reachable from) the "reference"?
1029 */
1030int in_merge_bases(struct commit *commit, struct commit *reference)
1031{
1032        return in_merge_bases_many(commit, 1, &reference);
1033}
1034
1035struct commit_list *reduce_heads(struct commit_list *heads)
1036{
1037        struct commit_list *p;
1038        struct commit_list *result = NULL, **tail = &result;
1039        struct commit **array;
1040        int num_head, i;
1041
1042        if (!heads)
1043                return NULL;
1044
1045        /* Uniquify */
1046        for (p = heads; p; p = p->next)
1047                p->item->object.flags &= ~STALE;
1048        for (p = heads, num_head = 0; p; p = p->next) {
1049                if (p->item->object.flags & STALE)
1050                        continue;
1051                p->item->object.flags |= STALE;
1052                num_head++;
1053        }
1054        array = xcalloc(num_head, sizeof(*array));
1055        for (p = heads, i = 0; p; p = p->next) {
1056                if (p->item->object.flags & STALE) {
1057                        array[i++] = p->item;
1058                        p->item->object.flags &= ~STALE;
1059                }
1060        }
1061        num_head = remove_redundant(array, num_head);
1062        for (i = 0; i < num_head; i++)
1063                tail = &commit_list_insert(array[i], tail)->next;
1064        return result;
1065}
1066
1067static const char gpg_sig_header[] = "gpgsig";
1068static const int gpg_sig_header_len = sizeof(gpg_sig_header) - 1;
1069
1070static int do_sign_commit(struct strbuf *buf, const char *keyid)
1071{
1072        struct strbuf sig = STRBUF_INIT;
1073        int inspos, copypos;
1074
1075        /* find the end of the header */
1076        inspos = strstr(buf->buf, "\n\n") - buf->buf + 1;
1077
1078        if (!keyid || !*keyid)
1079                keyid = get_signing_key();
1080        if (sign_buffer(buf, &sig, keyid)) {
1081                strbuf_release(&sig);
1082                return -1;
1083        }
1084
1085        for (copypos = 0; sig.buf[copypos]; ) {
1086                const char *bol = sig.buf + copypos;
1087                const char *eol = strchrnul(bol, '\n');
1088                int len = (eol - bol) + !!*eol;
1089
1090                if (!copypos) {
1091                        strbuf_insert(buf, inspos, gpg_sig_header, gpg_sig_header_len);
1092                        inspos += gpg_sig_header_len;
1093                }
1094                strbuf_insert(buf, inspos++, " ", 1);
1095                strbuf_insert(buf, inspos, bol, len);
1096                inspos += len;
1097                copypos += len;
1098        }
1099        strbuf_release(&sig);
1100        return 0;
1101}
1102
1103int parse_signed_commit(const struct commit *commit,
1104                        struct strbuf *payload, struct strbuf *signature)
1105{
1106
1107        unsigned long size;
1108        const char *buffer = get_commit_buffer(commit, &size);
1109        int in_signature, saw_signature = -1;
1110        const char *line, *tail;
1111
1112        line = buffer;
1113        tail = buffer + size;
1114        in_signature = 0;
1115        saw_signature = 0;
1116        while (line < tail) {
1117                const char *sig = NULL;
1118                const char *next = memchr(line, '\n', tail - line);
1119
1120                next = next ? next + 1 : tail;
1121                if (in_signature && line[0] == ' ')
1122                        sig = line + 1;
1123                else if (starts_with(line, gpg_sig_header) &&
1124                         line[gpg_sig_header_len] == ' ')
1125                        sig = line + gpg_sig_header_len + 1;
1126                if (sig) {
1127                        strbuf_add(signature, sig, next - sig);
1128                        saw_signature = 1;
1129                        in_signature = 1;
1130                } else {
1131                        if (*line == '\n')
1132                                /* dump the whole remainder of the buffer */
1133                                next = tail;
1134                        strbuf_add(payload, line, next - line);
1135                        in_signature = 0;
1136                }
1137                line = next;
1138        }
1139        unuse_commit_buffer(commit, buffer);
1140        return saw_signature;
1141}
1142
1143int remove_signature(struct strbuf *buf)
1144{
1145        const char *line = buf->buf;
1146        const char *tail = buf->buf + buf->len;
1147        int in_signature = 0;
1148        const char *sig_start = NULL;
1149        const char *sig_end = NULL;
1150
1151        while (line < tail) {
1152                const char *next = memchr(line, '\n', tail - line);
1153                next = next ? next + 1 : tail;
1154
1155                if (in_signature && line[0] == ' ')
1156                        sig_end = next;
1157                else if (starts_with(line, gpg_sig_header) &&
1158                         line[gpg_sig_header_len] == ' ') {
1159                        sig_start = line;
1160                        sig_end = next;
1161                        in_signature = 1;
1162                } else {
1163                        if (*line == '\n')
1164                                /* dump the whole remainder of the buffer */
1165                                next = tail;
1166                        in_signature = 0;
1167                }
1168                line = next;
1169        }
1170
1171        if (sig_start)
1172                strbuf_remove(buf, sig_start - buf->buf, sig_end - sig_start);
1173
1174        return sig_start != NULL;
1175}
1176
1177static void handle_signed_tag(struct commit *parent, struct commit_extra_header ***tail)
1178{
1179        struct merge_remote_desc *desc;
1180        struct commit_extra_header *mergetag;
1181        char *buf;
1182        unsigned long size, len;
1183        enum object_type type;
1184
1185        desc = merge_remote_util(parent);
1186        if (!desc || !desc->obj)
1187                return;
1188        buf = read_sha1_file(desc->obj->sha1, &type, &size);
1189        if (!buf || type != OBJ_TAG)
1190                goto free_return;
1191        len = parse_signature(buf, size);
1192        if (size == len)
1193                goto free_return;
1194        /*
1195         * We could verify this signature and either omit the tag when
1196         * it does not validate, but the integrator may not have the
1197         * public key of the signer of the tag he is merging, while a
1198         * later auditor may have it while auditing, so let's not run
1199         * verify-signed-buffer here for now...
1200         *
1201         * if (verify_signed_buffer(buf, len, buf + len, size - len, ...))
1202         *      warn("warning: signed tag unverified.");
1203         */
1204        mergetag = xcalloc(1, sizeof(*mergetag));
1205        mergetag->key = xstrdup("mergetag");
1206        mergetag->value = buf;
1207        mergetag->len = size;
1208
1209        **tail = mergetag;
1210        *tail = &mergetag->next;
1211        return;
1212
1213free_return:
1214        free(buf);
1215}
1216
1217void check_commit_signature(const struct commit *commit, struct signature_check *sigc)
1218{
1219        struct strbuf payload = STRBUF_INIT;
1220        struct strbuf signature = STRBUF_INIT;
1221        struct strbuf gpg_output = STRBUF_INIT;
1222        struct strbuf gpg_status = STRBUF_INIT;
1223        int status;
1224
1225        sigc->result = 'N';
1226
1227        if (parse_signed_commit(commit, &payload, &signature) <= 0)
1228                goto out;
1229        status = verify_signed_buffer(payload.buf, payload.len,
1230                                      signature.buf, signature.len,
1231                                      &gpg_output, &gpg_status);
1232        if (status && !gpg_output.len)
1233                goto out;
1234        sigc->payload = strbuf_detach(&payload, NULL);
1235        sigc->gpg_output = strbuf_detach(&gpg_output, NULL);
1236        sigc->gpg_status = strbuf_detach(&gpg_status, NULL);
1237        parse_gpg_output(sigc);
1238
1239 out:
1240        strbuf_release(&gpg_status);
1241        strbuf_release(&gpg_output);
1242        strbuf_release(&payload);
1243        strbuf_release(&signature);
1244}
1245
1246
1247
1248void append_merge_tag_headers(struct commit_list *parents,
1249                              struct commit_extra_header ***tail)
1250{
1251        while (parents) {
1252                struct commit *parent = parents->item;
1253                handle_signed_tag(parent, tail);
1254                parents = parents->next;
1255        }
1256}
1257
1258static void add_extra_header(struct strbuf *buffer,
1259                             struct commit_extra_header *extra)
1260{
1261        strbuf_addstr(buffer, extra->key);
1262        if (extra->len)
1263                strbuf_add_lines(buffer, " ", extra->value, extra->len);
1264        else
1265                strbuf_addch(buffer, '\n');
1266}
1267
1268struct commit_extra_header *read_commit_extra_headers(struct commit *commit,
1269                                                      const char **exclude)
1270{
1271        struct commit_extra_header *extra = NULL;
1272        unsigned long size;
1273        const char *buffer = get_commit_buffer(commit, &size);
1274        extra = read_commit_extra_header_lines(buffer, size, exclude);
1275        unuse_commit_buffer(commit, buffer);
1276        return extra;
1277}
1278
1279void for_each_mergetag(each_mergetag_fn fn, struct commit *commit, void *data)
1280{
1281        struct commit_extra_header *extra, *to_free;
1282
1283        to_free = read_commit_extra_headers(commit, NULL);
1284        for (extra = to_free; extra; extra = extra->next) {
1285                if (strcmp(extra->key, "mergetag"))
1286                        continue; /* not a merge tag */
1287                fn(commit, extra, data);
1288        }
1289        free_commit_extra_headers(to_free);
1290}
1291
1292static inline int standard_header_field(const char *field, size_t len)
1293{
1294        return ((len == 4 && !memcmp(field, "tree ", 5)) ||
1295                (len == 6 && !memcmp(field, "parent ", 7)) ||
1296                (len == 6 && !memcmp(field, "author ", 7)) ||
1297                (len == 9 && !memcmp(field, "committer ", 10)) ||
1298                (len == 8 && !memcmp(field, "encoding ", 9)));
1299}
1300
1301static int excluded_header_field(const char *field, size_t len, const char **exclude)
1302{
1303        if (!exclude)
1304                return 0;
1305
1306        while (*exclude) {
1307                size_t xlen = strlen(*exclude);
1308                if (len == xlen &&
1309                    !memcmp(field, *exclude, xlen) && field[xlen] == ' ')
1310                        return 1;
1311                exclude++;
1312        }
1313        return 0;
1314}
1315
1316static struct commit_extra_header *read_commit_extra_header_lines(
1317        const char *buffer, size_t size,
1318        const char **exclude)
1319{
1320        struct commit_extra_header *extra = NULL, **tail = &extra, *it = NULL;
1321        const char *line, *next, *eof, *eob;
1322        struct strbuf buf = STRBUF_INIT;
1323
1324        for (line = buffer, eob = line + size;
1325             line < eob && *line != '\n';
1326             line = next) {
1327                next = memchr(line, '\n', eob - line);
1328                next = next ? next + 1 : eob;
1329                if (*line == ' ') {
1330                        /* continuation */
1331                        if (it)
1332                                strbuf_add(&buf, line + 1, next - (line + 1));
1333                        continue;
1334                }
1335                if (it)
1336                        it->value = strbuf_detach(&buf, &it->len);
1337                strbuf_reset(&buf);
1338                it = NULL;
1339
1340                eof = strchr(line, ' ');
1341                if (next <= eof)
1342                        eof = next;
1343
1344                if (standard_header_field(line, eof - line) ||
1345                    excluded_header_field(line, eof - line, exclude))
1346                        continue;
1347
1348                it = xcalloc(1, sizeof(*it));
1349                it->key = xmemdupz(line, eof-line);
1350                *tail = it;
1351                tail = &it->next;
1352                if (eof + 1 < next)
1353                        strbuf_add(&buf, eof + 1, next - (eof + 1));
1354        }
1355        if (it)
1356                it->value = strbuf_detach(&buf, &it->len);
1357        return extra;
1358}
1359
1360void free_commit_extra_headers(struct commit_extra_header *extra)
1361{
1362        while (extra) {
1363                struct commit_extra_header *next = extra->next;
1364                free(extra->key);
1365                free(extra->value);
1366                free(extra);
1367                extra = next;
1368        }
1369}
1370
1371int commit_tree(const char *msg, size_t msg_len,
1372                const unsigned char *tree,
1373                struct commit_list *parents, unsigned char *ret,
1374                const char *author, const char *sign_commit)
1375{
1376        struct commit_extra_header *extra = NULL, **tail = &extra;
1377        int result;
1378
1379        append_merge_tag_headers(parents, &tail);
1380        result = commit_tree_extended(msg, msg_len, tree, parents, ret,
1381                                      author, sign_commit, extra);
1382        free_commit_extra_headers(extra);
1383        return result;
1384}
1385
1386static int find_invalid_utf8(const char *buf, int len)
1387{
1388        int offset = 0;
1389        static const unsigned int max_codepoint[] = {
1390                0x7f, 0x7ff, 0xffff, 0x10ffff
1391        };
1392
1393        while (len) {
1394                unsigned char c = *buf++;
1395                int bytes, bad_offset;
1396                unsigned int codepoint;
1397                unsigned int min_val, max_val;
1398
1399                len--;
1400                offset++;
1401
1402                /* Simple US-ASCII? No worries. */
1403                if (c < 0x80)
1404                        continue;
1405
1406                bad_offset = offset-1;
1407
1408                /*
1409                 * Count how many more high bits set: that's how
1410                 * many more bytes this sequence should have.
1411                 */
1412                bytes = 0;
1413                while (c & 0x40) {
1414                        c <<= 1;
1415                        bytes++;
1416                }
1417
1418                /*
1419                 * Must be between 1 and 3 more bytes.  Longer sequences result in
1420                 * codepoints beyond U+10FFFF, which are guaranteed never to exist.
1421                 */
1422                if (bytes < 1 || 3 < bytes)
1423                        return bad_offset;
1424
1425                /* Do we *have* that many bytes? */
1426                if (len < bytes)
1427                        return bad_offset;
1428
1429                /*
1430                 * Place the encoded bits at the bottom of the value and compute the
1431                 * valid range.
1432                 */
1433                codepoint = (c & 0x7f) >> bytes;
1434                min_val = max_codepoint[bytes-1] + 1;
1435                max_val = max_codepoint[bytes];
1436
1437                offset += bytes;
1438                len -= bytes;
1439
1440                /* And verify that they are good continuation bytes */
1441                do {
1442                        codepoint <<= 6;
1443                        codepoint |= *buf & 0x3f;
1444                        if ((*buf++ & 0xc0) != 0x80)
1445                                return bad_offset;
1446                } while (--bytes);
1447
1448                /* Reject codepoints that are out of range for the sequence length. */
1449                if (codepoint < min_val || codepoint > max_val)
1450                        return bad_offset;
1451                /* Surrogates are only for UTF-16 and cannot be encoded in UTF-8. */
1452                if ((codepoint & 0x1ff800) == 0xd800)
1453                        return bad_offset;
1454                /* U+xxFFFE and U+xxFFFF are guaranteed non-characters. */
1455                if ((codepoint & 0xfffe) == 0xfffe)
1456                        return bad_offset;
1457                /* So are anything in the range U+FDD0..U+FDEF. */
1458                if (codepoint >= 0xfdd0 && codepoint <= 0xfdef)
1459                        return bad_offset;
1460        }
1461        return -1;
1462}
1463
1464/*
1465 * This verifies that the buffer is in proper utf8 format.
1466 *
1467 * If it isn't, it assumes any non-utf8 characters are Latin1,
1468 * and does the conversion.
1469 */
1470static int verify_utf8(struct strbuf *buf)
1471{
1472        int ok = 1;
1473        long pos = 0;
1474
1475        for (;;) {
1476                int bad;
1477                unsigned char c;
1478                unsigned char replace[2];
1479
1480                bad = find_invalid_utf8(buf->buf + pos, buf->len - pos);
1481                if (bad < 0)
1482                        return ok;
1483                pos += bad;
1484                ok = 0;
1485                c = buf->buf[pos];
1486                strbuf_remove(buf, pos, 1);
1487
1488                /* We know 'c' must be in the range 128-255 */
1489                replace[0] = 0xc0 + (c >> 6);
1490                replace[1] = 0x80 + (c & 0x3f);
1491                strbuf_insert(buf, pos, replace, 2);
1492                pos += 2;
1493        }
1494}
1495
1496static const char commit_utf8_warn[] =
1497"Warning: commit message did not conform to UTF-8.\n"
1498"You may want to amend it after fixing the message, or set the config\n"
1499"variable i18n.commitencoding to the encoding your project uses.\n";
1500
1501int commit_tree_extended(const char *msg, size_t msg_len,
1502                         const unsigned char *tree,
1503                         struct commit_list *parents, unsigned char *ret,
1504                         const char *author, const char *sign_commit,
1505                         struct commit_extra_header *extra)
1506{
1507        int result;
1508        int encoding_is_utf8;
1509        struct strbuf buffer;
1510
1511        assert_sha1_type(tree, OBJ_TREE);
1512
1513        if (memchr(msg, '\0', msg_len))
1514                return error("a NUL byte in commit log message not allowed.");
1515
1516        /* Not having i18n.commitencoding is the same as having utf-8 */
1517        encoding_is_utf8 = is_encoding_utf8(git_commit_encoding);
1518
1519        strbuf_init(&buffer, 8192); /* should avoid reallocs for the headers */
1520        strbuf_addf(&buffer, "tree %s\n", sha1_to_hex(tree));
1521
1522        /*
1523         * NOTE! This ordering means that the same exact tree merged with a
1524         * different order of parents will be a _different_ changeset even
1525         * if everything else stays the same.
1526         */
1527        while (parents) {
1528                struct commit_list *next = parents->next;
1529                struct commit *parent = parents->item;
1530
1531                strbuf_addf(&buffer, "parent %s\n",
1532                            sha1_to_hex(parent->object.sha1));
1533                free(parents);
1534                parents = next;
1535        }
1536
1537        /* Person/date information */
1538        if (!author)
1539                author = git_author_info(IDENT_STRICT);
1540        strbuf_addf(&buffer, "author %s\n", author);
1541        strbuf_addf(&buffer, "committer %s\n", git_committer_info(IDENT_STRICT));
1542        if (!encoding_is_utf8)
1543                strbuf_addf(&buffer, "encoding %s\n", git_commit_encoding);
1544
1545        while (extra) {
1546                add_extra_header(&buffer, extra);
1547                extra = extra->next;
1548        }
1549        strbuf_addch(&buffer, '\n');
1550
1551        /* And add the comment */
1552        strbuf_add(&buffer, msg, msg_len);
1553
1554        /* And check the encoding */
1555        if (encoding_is_utf8 && !verify_utf8(&buffer))
1556                fprintf(stderr, commit_utf8_warn);
1557
1558        if (sign_commit && do_sign_commit(&buffer, sign_commit))
1559                return -1;
1560
1561        result = write_sha1_file(buffer.buf, buffer.len, commit_type, ret);
1562        strbuf_release(&buffer);
1563        return result;
1564}
1565
1566struct commit *get_merge_parent(const char *name)
1567{
1568        struct object *obj;
1569        struct commit *commit;
1570        unsigned char sha1[20];
1571        if (get_sha1(name, sha1))
1572                return NULL;
1573        obj = parse_object(sha1);
1574        commit = (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
1575        if (commit && !commit->util) {
1576                struct merge_remote_desc *desc;
1577                desc = xmalloc(sizeof(*desc));
1578                desc->obj = obj;
1579                desc->name = strdup(name);
1580                commit->util = desc;
1581        }
1582        return commit;
1583}
1584
1585/*
1586 * Append a commit to the end of the commit_list.
1587 *
1588 * next starts by pointing to the variable that holds the head of an
1589 * empty commit_list, and is updated to point to the "next" field of
1590 * the last item on the list as new commits are appended.
1591 *
1592 * Usage example:
1593 *
1594 *     struct commit_list *list;
1595 *     struct commit_list **next = &list;
1596 *
1597 *     next = commit_list_append(c1, next);
1598 *     next = commit_list_append(c2, next);
1599 *     assert(commit_list_count(list) == 2);
1600 *     return list;
1601 */
1602struct commit_list **commit_list_append(struct commit *commit,
1603                                        struct commit_list **next)
1604{
1605        struct commit_list *new = xmalloc(sizeof(struct commit_list));
1606        new->item = commit;
1607        *next = new;
1608        new->next = NULL;
1609        return &new->next;
1610}
1611
1612void print_commit_list(struct commit_list *list,
1613                       const char *format_cur,
1614                       const char *format_last)
1615{
1616        for ( ; list; list = list->next) {
1617                const char *format = list->next ? format_cur : format_last;
1618                printf(format, sha1_to_hex(list->item->object.sha1));
1619        }
1620}
1621
1622const char *find_commit_header(const char *msg, const char *key, size_t *out_len)
1623{
1624        int key_len = strlen(key);
1625        const char *line = msg;
1626
1627        while (line) {
1628                const char *eol = strchrnul(line, '\n');
1629
1630                if (line == eol)
1631                        return NULL;
1632
1633                if (eol - line > key_len &&
1634                    !strncmp(line, key, key_len) &&
1635                    line[key_len] == ' ') {
1636                        *out_len = eol - line - key_len - 1;
1637                        return line + key_len + 1;
1638                }
1639                line = *eol ? eol + 1 : NULL;
1640        }
1641        return NULL;
1642}