Andrew's git / gitweb.git / commit.c
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commit.con commit add tests for `git_config_get_string_const()` (8a7b034)
   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 *buf, *line_end, *ident_line;
 588        const char *buffer = get_commit_buffer(commit, NULL);
 589        struct ident_split ident;
 590        char *date_end;
 591        unsigned long date;
 592
 593        for (buf = buffer; buf; buf = line_end + 1) {
 594                line_end = strchrnul(buf, '\n');
 595                if (!skip_prefix(buf, "author ", &ident_line)) {
 596                        if (!line_end[0] || line_end[1] == '\n')
 597                                return; /* end of header */
 598                        continue;
 599                }
 600                if (split_ident_line(&ident,
 601                                     ident_line, line_end - ident_line) ||
 602                    !ident.date_begin || !ident.date_end)
 603                        goto fail_exit; /* malformed "author" line */
 604                break;
 605        }
 606
 607        date = strtoul(ident.date_begin, &date_end, 10);
 608        if (date_end != ident.date_end)
 609                goto fail_exit; /* malformed date */
 610        *(author_date_slab_at(author_date, commit)) = date;
 611
 612fail_exit:
 613        unuse_commit_buffer(commit, buffer);
 614}
 615
 616static int compare_commits_by_author_date(const void *a_, const void *b_,
 617                                          void *cb_data)
 618{
 619        const struct commit *a = a_, *b = b_;
 620        struct author_date_slab *author_date = cb_data;
 621        unsigned long a_date = *(author_date_slab_at(author_date, a));
 622        unsigned long b_date = *(author_date_slab_at(author_date, b));
 623
 624        /* newer commits with larger date first */
 625        if (a_date < b_date)
 626                return 1;
 627        else if (a_date > b_date)
 628                return -1;
 629        return 0;
 630}
 631
 632int compare_commits_by_commit_date(const void *a_, const void *b_, void *unused)
 633{
 634        const struct commit *a = a_, *b = b_;
 635        /* newer commits with larger date first */
 636        if (a->date < b->date)
 637                return 1;
 638        else if (a->date > b->date)
 639                return -1;
 640        return 0;
 641}
 642
 643/*
 644 * Performs an in-place topological sort on the list supplied.
 645 */
 646void sort_in_topological_order(struct commit_list **list, enum rev_sort_order sort_order)
 647{
 648        struct commit_list *next, *orig = *list;
 649        struct commit_list **pptr;
 650        struct indegree_slab indegree;
 651        struct prio_queue queue;
 652        struct commit *commit;
 653        struct author_date_slab author_date;
 654
 655        if (!orig)
 656                return;
 657        *list = NULL;
 658
 659        init_indegree_slab(&indegree);
 660        memset(&queue, '\0', sizeof(queue));
 661
 662        switch (sort_order) {
 663        default: /* REV_SORT_IN_GRAPH_ORDER */
 664                queue.compare = NULL;
 665                break;
 666        case REV_SORT_BY_COMMIT_DATE:
 667                queue.compare = compare_commits_by_commit_date;
 668                break;
 669        case REV_SORT_BY_AUTHOR_DATE:
 670                init_author_date_slab(&author_date);
 671                queue.compare = compare_commits_by_author_date;
 672                queue.cb_data = &author_date;
 673                break;
 674        }
 675
 676        /* Mark them and clear the indegree */
 677        for (next = orig; next; next = next->next) {
 678                struct commit *commit = next->item;
 679                *(indegree_slab_at(&indegree, commit)) = 1;
 680                /* also record the author dates, if needed */
 681                if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 682                        record_author_date(&author_date, commit);
 683        }
 684
 685        /* update the indegree */
 686        for (next = orig; next; next = next->next) {
 687                struct commit_list *parents = next->item->parents;
 688                while (parents) {
 689                        struct commit *parent = parents->item;
 690                        int *pi = indegree_slab_at(&indegree, parent);
 691
 692                        if (*pi)
 693                                (*pi)++;
 694                        parents = parents->next;
 695                }
 696        }
 697
 698        /*
 699         * find the tips
 700         *
 701         * tips are nodes not reachable from any other node in the list
 702         *
 703         * the tips serve as a starting set for the work queue.
 704         */
 705        for (next = orig; next; next = next->next) {
 706                struct commit *commit = next->item;
 707
 708                if (*(indegree_slab_at(&indegree, commit)) == 1)
 709                        prio_queue_put(&queue, commit);
 710        }
 711
 712        /*
 713         * This is unfortunate; the initial tips need to be shown
 714         * in the order given from the revision traversal machinery.
 715         */
 716        if (sort_order == REV_SORT_IN_GRAPH_ORDER)
 717                prio_queue_reverse(&queue);
 718
 719        /* We no longer need the commit list */
 720        free_commit_list(orig);
 721
 722        pptr = list;
 723        *list = NULL;
 724        while ((commit = prio_queue_get(&queue)) != NULL) {
 725                struct commit_list *parents;
 726
 727                for (parents = commit->parents; parents ; parents = parents->next) {
 728                        struct commit *parent = parents->item;
 729                        int *pi = indegree_slab_at(&indegree, parent);
 730
 731                        if (!*pi)
 732                                continue;
 733
 734                        /*
 735                         * parents are only enqueued for emission
 736                         * when all their children have been emitted thereby
 737                         * guaranteeing topological order.
 738                         */
 739                        if (--(*pi) == 1)
 740                                prio_queue_put(&queue, parent);
 741                }
 742                /*
 743                 * all children of commit have already been
 744                 * emitted. we can emit it now.
 745                 */
 746                *(indegree_slab_at(&indegree, commit)) = 0;
 747
 748                pptr = &commit_list_insert(commit, pptr)->next;
 749        }
 750
 751        clear_indegree_slab(&indegree);
 752        clear_prio_queue(&queue);
 753        if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 754                clear_author_date_slab(&author_date);
 755}
 756
 757/* merge-base stuff */
 758
 759/* Remember to update object flag allocation in object.h */
 760#define PARENT1         (1u<<16)
 761#define PARENT2         (1u<<17)
 762#define STALE           (1u<<18)
 763#define RESULT          (1u<<19)
 764
 765static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
 766
 767static struct commit *interesting(struct commit_list *list)
 768{
 769        while (list) {
 770                struct commit *commit = list->item;
 771                list = list->next;
 772                if (commit->object.flags & STALE)
 773                        continue;
 774                return commit;
 775        }
 776        return NULL;
 777}
 778
 779/* all input commits in one and twos[] must have been parsed! */
 780static struct commit_list *paint_down_to_common(struct commit *one, int n, struct commit **twos)
 781{
 782        struct commit_list *list = NULL;
 783        struct commit_list *result = NULL;
 784        int i;
 785
 786        one->object.flags |= PARENT1;
 787        commit_list_insert_by_date(one, &list);
 788        if (!n)
 789                return list;
 790        for (i = 0; i < n; i++) {
 791                twos[i]->object.flags |= PARENT2;
 792                commit_list_insert_by_date(twos[i], &list);
 793        }
 794
 795        while (interesting(list)) {
 796                struct commit *commit;
 797                struct commit_list *parents;
 798                struct commit_list *next;
 799                int flags;
 800
 801                commit = list->item;
 802                next = list->next;
 803                free(list);
 804                list = next;
 805
 806                flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
 807                if (flags == (PARENT1 | PARENT2)) {
 808                        if (!(commit->object.flags & RESULT)) {
 809                                commit->object.flags |= RESULT;
 810                                commit_list_insert_by_date(commit, &result);
 811                        }
 812                        /* Mark parents of a found merge stale */
 813                        flags |= STALE;
 814                }
 815                parents = commit->parents;
 816                while (parents) {
 817                        struct commit *p = parents->item;
 818                        parents = parents->next;
 819                        if ((p->object.flags & flags) == flags)
 820                                continue;
 821                        if (parse_commit(p))
 822                                return NULL;
 823                        p->object.flags |= flags;
 824                        commit_list_insert_by_date(p, &list);
 825                }
 826        }
 827
 828        free_commit_list(list);
 829        return result;
 830}
 831
 832static struct commit_list *merge_bases_many(struct commit *one, int n, struct commit **twos)
 833{
 834        struct commit_list *list = NULL;
 835        struct commit_list *result = NULL;
 836        int i;
 837
 838        for (i = 0; i < n; i++) {
 839                if (one == twos[i])
 840                        /*
 841                         * We do not mark this even with RESULT so we do not
 842                         * have to clean it up.
 843                         */
 844                        return commit_list_insert(one, &result);
 845        }
 846
 847        if (parse_commit(one))
 848                return NULL;
 849        for (i = 0; i < n; i++) {
 850                if (parse_commit(twos[i]))
 851                        return NULL;
 852        }
 853
 854        list = paint_down_to_common(one, n, twos);
 855
 856        while (list) {
 857                struct commit_list *next = list->next;
 858                if (!(list->item->object.flags & STALE))
 859                        commit_list_insert_by_date(list->item, &result);
 860                free(list);
 861                list = next;
 862        }
 863        return result;
 864}
 865
 866struct commit_list *get_octopus_merge_bases(struct commit_list *in)
 867{
 868        struct commit_list *i, *j, *k, *ret = NULL;
 869
 870        if (!in)
 871                return ret;
 872
 873        commit_list_insert(in->item, &ret);
 874
 875        for (i = in->next; i; i = i->next) {
 876                struct commit_list *new = NULL, *end = NULL;
 877
 878                for (j = ret; j; j = j->next) {
 879                        struct commit_list *bases;
 880                        bases = get_merge_bases(i->item, j->item, 1);
 881                        if (!new)
 882                                new = bases;
 883                        else
 884                                end->next = bases;
 885                        for (k = bases; k; k = k->next)
 886                                end = k;
 887                }
 888                ret = new;
 889        }
 890        return ret;
 891}
 892
 893static int remove_redundant(struct commit **array, int cnt)
 894{
 895        /*
 896         * Some commit in the array may be an ancestor of
 897         * another commit.  Move such commit to the end of
 898         * the array, and return the number of commits that
 899         * are independent from each other.
 900         */
 901        struct commit **work;
 902        unsigned char *redundant;
 903        int *filled_index;
 904        int i, j, filled;
 905
 906        work = xcalloc(cnt, sizeof(*work));
 907        redundant = xcalloc(cnt, 1);
 908        filled_index = xmalloc(sizeof(*filled_index) * (cnt - 1));
 909
 910        for (i = 0; i < cnt; i++)
 911                parse_commit(array[i]);
 912        for (i = 0; i < cnt; i++) {
 913                struct commit_list *common;
 914
 915                if (redundant[i])
 916                        continue;
 917                for (j = filled = 0; j < cnt; j++) {
 918                        if (i == j || redundant[j])
 919                                continue;
 920                        filled_index[filled] = j;
 921                        work[filled++] = array[j];
 922                }
 923                common = paint_down_to_common(array[i], filled, work);
 924                if (array[i]->object.flags & PARENT2)
 925                        redundant[i] = 1;
 926                for (j = 0; j < filled; j++)
 927                        if (work[j]->object.flags & PARENT1)
 928                                redundant[filled_index[j]] = 1;
 929                clear_commit_marks(array[i], all_flags);
 930                for (j = 0; j < filled; j++)
 931                        clear_commit_marks(work[j], all_flags);
 932                free_commit_list(common);
 933        }
 934
 935        /* Now collect the result */
 936        memcpy(work, array, sizeof(*array) * cnt);
 937        for (i = filled = 0; i < cnt; i++)
 938                if (!redundant[i])
 939                        array[filled++] = work[i];
 940        for (j = filled, i = 0; i < cnt; i++)
 941                if (redundant[i])
 942                        array[j++] = work[i];
 943        free(work);
 944        free(redundant);
 945        free(filled_index);
 946        return filled;
 947}
 948
 949struct commit_list *get_merge_bases_many(struct commit *one,
 950                                         int n,
 951                                         struct commit **twos,
 952                                         int cleanup)
 953{
 954        struct commit_list *list;
 955        struct commit **rslt;
 956        struct commit_list *result;
 957        int cnt, i;
 958
 959        result = merge_bases_many(one, n, twos);
 960        for (i = 0; i < n; i++) {
 961                if (one == twos[i])
 962                        return result;
 963        }
 964        if (!result || !result->next) {
 965                if (cleanup) {
 966                        clear_commit_marks(one, all_flags);
 967                        clear_commit_marks_many(n, twos, all_flags);
 968                }
 969                return result;
 970        }
 971
 972        /* There are more than one */
 973        cnt = commit_list_count(result);
 974        rslt = xcalloc(cnt, sizeof(*rslt));
 975        for (list = result, i = 0; list; list = list->next)
 976                rslt[i++] = list->item;
 977        free_commit_list(result);
 978
 979        clear_commit_marks(one, all_flags);
 980        clear_commit_marks_many(n, twos, all_flags);
 981
 982        cnt = remove_redundant(rslt, cnt);
 983        result = NULL;
 984        for (i = 0; i < cnt; i++)
 985                commit_list_insert_by_date(rslt[i], &result);
 986        free(rslt);
 987        return result;
 988}
 989
 990struct commit_list *get_merge_bases(struct commit *one, struct commit *two,
 991                                    int cleanup)
 992{
 993        return get_merge_bases_many(one, 1, &two, cleanup);
 994}
 995
 996/*
 997 * Is "commit" a descendant of one of the elements on the "with_commit" list?
 998 */
 999int is_descendant_of(struct commit *commit, struct commit_list *with_commit)
1000{
1001        if (!with_commit)
1002                return 1;
1003        while (with_commit) {
1004                struct commit *other;
1005
1006                other = with_commit->item;
1007                with_commit = with_commit->next;
1008                if (in_merge_bases(other, commit))
1009                        return 1;
1010        }
1011        return 0;
1012}
1013
1014/*
1015 * Is "commit" an ancestor of one of the "references"?
1016 */
1017int in_merge_bases_many(struct commit *commit, int nr_reference, struct commit **reference)
1018{
1019        struct commit_list *bases;
1020        int ret = 0, i;
1021
1022        if (parse_commit(commit))
1023                return ret;
1024        for (i = 0; i < nr_reference; i++)
1025                if (parse_commit(reference[i]))
1026                        return ret;
1027
1028        bases = paint_down_to_common(commit, nr_reference, reference);
1029        if (commit->object.flags & PARENT2)
1030                ret = 1;
1031        clear_commit_marks(commit, all_flags);
1032        clear_commit_marks_many(nr_reference, reference, all_flags);
1033        free_commit_list(bases);
1034        return ret;
1035}
1036
1037/*
1038 * Is "commit" an ancestor of (i.e. reachable from) the "reference"?
1039 */
1040int in_merge_bases(struct commit *commit, struct commit *reference)
1041{
1042        return in_merge_bases_many(commit, 1, &reference);
1043}
1044
1045struct commit_list *reduce_heads(struct commit_list *heads)
1046{
1047        struct commit_list *p;
1048        struct commit_list *result = NULL, **tail = &result;
1049        struct commit **array;
1050        int num_head, i;
1051
1052        if (!heads)
1053                return NULL;
1054
1055        /* Uniquify */
1056        for (p = heads; p; p = p->next)
1057                p->item->object.flags &= ~STALE;
1058        for (p = heads, num_head = 0; p; p = p->next) {
1059                if (p->item->object.flags & STALE)
1060                        continue;
1061                p->item->object.flags |= STALE;
1062                num_head++;
1063        }
1064        array = xcalloc(num_head, sizeof(*array));
1065        for (p = heads, i = 0; p; p = p->next) {
1066                if (p->item->object.flags & STALE) {
1067                        array[i++] = p->item;
1068                        p->item->object.flags &= ~STALE;
1069                }
1070        }
1071        num_head = remove_redundant(array, num_head);
1072        for (i = 0; i < num_head; i++)
1073                tail = &commit_list_insert(array[i], tail)->next;
1074        return result;
1075}
1076
1077static const char gpg_sig_header[] = "gpgsig";
1078static const int gpg_sig_header_len = sizeof(gpg_sig_header) - 1;
1079
1080static int do_sign_commit(struct strbuf *buf, const char *keyid)
1081{
1082        struct strbuf sig = STRBUF_INIT;
1083        int inspos, copypos;
1084
1085        /* find the end of the header */
1086        inspos = strstr(buf->buf, "\n\n") - buf->buf + 1;
1087
1088        if (!keyid || !*keyid)
1089                keyid = get_signing_key();
1090        if (sign_buffer(buf, &sig, keyid)) {
1091                strbuf_release(&sig);
1092                return -1;
1093        }
1094
1095        for (copypos = 0; sig.buf[copypos]; ) {
1096                const char *bol = sig.buf + copypos;
1097                const char *eol = strchrnul(bol, '\n');
1098                int len = (eol - bol) + !!*eol;
1099
1100                if (!copypos) {
1101                        strbuf_insert(buf, inspos, gpg_sig_header, gpg_sig_header_len);
1102                        inspos += gpg_sig_header_len;
1103                }
1104                strbuf_insert(buf, inspos++, " ", 1);
1105                strbuf_insert(buf, inspos, bol, len);
1106                inspos += len;
1107                copypos += len;
1108        }
1109        strbuf_release(&sig);
1110        return 0;
1111}
1112
1113int parse_signed_commit(const struct commit *commit,
1114                        struct strbuf *payload, struct strbuf *signature)
1115{
1116
1117        unsigned long size;
1118        const char *buffer = get_commit_buffer(commit, &size);
1119        int in_signature, saw_signature = -1;
1120        const char *line, *tail;
1121
1122        line = buffer;
1123        tail = buffer + size;
1124        in_signature = 0;
1125        saw_signature = 0;
1126        while (line < tail) {
1127                const char *sig = NULL;
1128                const char *next = memchr(line, '\n', tail - line);
1129
1130                next = next ? next + 1 : tail;
1131                if (in_signature && line[0] == ' ')
1132                        sig = line + 1;
1133                else if (starts_with(line, gpg_sig_header) &&
1134                         line[gpg_sig_header_len] == ' ')
1135                        sig = line + gpg_sig_header_len + 1;
1136                if (sig) {
1137                        strbuf_add(signature, sig, next - sig);
1138                        saw_signature = 1;
1139                        in_signature = 1;
1140                } else {
1141                        if (*line == '\n')
1142                                /* dump the whole remainder of the buffer */
1143                                next = tail;
1144                        strbuf_add(payload, line, next - line);
1145                        in_signature = 0;
1146                }
1147                line = next;
1148        }
1149        unuse_commit_buffer(commit, buffer);
1150        return saw_signature;
1151}
1152
1153static void handle_signed_tag(struct commit *parent, struct commit_extra_header ***tail)
1154{
1155        struct merge_remote_desc *desc;
1156        struct commit_extra_header *mergetag;
1157        char *buf;
1158        unsigned long size, len;
1159        enum object_type type;
1160
1161        desc = merge_remote_util(parent);
1162        if (!desc || !desc->obj)
1163                return;
1164        buf = read_sha1_file(desc->obj->sha1, &type, &size);
1165        if (!buf || type != OBJ_TAG)
1166                goto free_return;
1167        len = parse_signature(buf, size);
1168        if (size == len)
1169                goto free_return;
1170        /*
1171         * We could verify this signature and either omit the tag when
1172         * it does not validate, but the integrator may not have the
1173         * public key of the signer of the tag he is merging, while a
1174         * later auditor may have it while auditing, so let's not run
1175         * verify-signed-buffer here for now...
1176         *
1177         * if (verify_signed_buffer(buf, len, buf + len, size - len, ...))
1178         *      warn("warning: signed tag unverified.");
1179         */
1180        mergetag = xcalloc(1, sizeof(*mergetag));
1181        mergetag->key = xstrdup("mergetag");
1182        mergetag->value = buf;
1183        mergetag->len = size;
1184
1185        **tail = mergetag;
1186        *tail = &mergetag->next;
1187        return;
1188
1189free_return:
1190        free(buf);
1191}
1192
1193static struct {
1194        char result;
1195        const char *check;
1196} sigcheck_gpg_status[] = {
1197        { 'G', "\n[GNUPG:] GOODSIG " },
1198        { 'B', "\n[GNUPG:] BADSIG " },
1199        { 'U', "\n[GNUPG:] TRUST_NEVER" },
1200        { 'U', "\n[GNUPG:] TRUST_UNDEFINED" },
1201};
1202
1203static void parse_gpg_output(struct signature_check *sigc)
1204{
1205        const char *buf = sigc->gpg_status;
1206        int i;
1207
1208        /* Iterate over all search strings */
1209        for (i = 0; i < ARRAY_SIZE(sigcheck_gpg_status); i++) {
1210                const char *found, *next;
1211
1212                if (!skip_prefix(buf, sigcheck_gpg_status[i].check + 1, &found)) {
1213                        found = strstr(buf, sigcheck_gpg_status[i].check);
1214                        if (!found)
1215                                continue;
1216                        found += strlen(sigcheck_gpg_status[i].check);
1217                }
1218                sigc->result = sigcheck_gpg_status[i].result;
1219                /* The trust messages are not followed by key/signer information */
1220                if (sigc->result != 'U') {
1221                        sigc->key = xmemdupz(found, 16);
1222                        found += 17;
1223                        next = strchrnul(found, '\n');
1224                        sigc->signer = xmemdupz(found, next - found);
1225                }
1226        }
1227}
1228
1229void check_commit_signature(const struct commit* commit, struct signature_check *sigc)
1230{
1231        struct strbuf payload = STRBUF_INIT;
1232        struct strbuf signature = STRBUF_INIT;
1233        struct strbuf gpg_output = STRBUF_INIT;
1234        struct strbuf gpg_status = STRBUF_INIT;
1235        int status;
1236
1237        sigc->result = 'N';
1238
1239        if (parse_signed_commit(commit, &payload, &signature) <= 0)
1240                goto out;
1241        status = verify_signed_buffer(payload.buf, payload.len,
1242                                      signature.buf, signature.len,
1243                                      &gpg_output, &gpg_status);
1244        if (status && !gpg_output.len)
1245                goto out;
1246        sigc->payload = strbuf_detach(&payload, NULL);
1247        sigc->gpg_output = strbuf_detach(&gpg_output, NULL);
1248        sigc->gpg_status = strbuf_detach(&gpg_status, NULL);
1249        parse_gpg_output(sigc);
1250
1251 out:
1252        strbuf_release(&gpg_status);
1253        strbuf_release(&gpg_output);
1254        strbuf_release(&payload);
1255        strbuf_release(&signature);
1256}
1257
1258
1259
1260void append_merge_tag_headers(struct commit_list *parents,
1261                              struct commit_extra_header ***tail)
1262{
1263        while (parents) {
1264                struct commit *parent = parents->item;
1265                handle_signed_tag(parent, tail);
1266                parents = parents->next;
1267        }
1268}
1269
1270static void add_extra_header(struct strbuf *buffer,
1271                             struct commit_extra_header *extra)
1272{
1273        strbuf_addstr(buffer, extra->key);
1274        if (extra->len)
1275                strbuf_add_lines(buffer, " ", extra->value, extra->len);
1276        else
1277                strbuf_addch(buffer, '\n');
1278}
1279
1280struct commit_extra_header *read_commit_extra_headers(struct commit *commit,
1281                                                      const char **exclude)
1282{
1283        struct commit_extra_header *extra = NULL;
1284        unsigned long size;
1285        const char *buffer = get_commit_buffer(commit, &size);
1286        extra = read_commit_extra_header_lines(buffer, size, exclude);
1287        unuse_commit_buffer(commit, buffer);
1288        return extra;
1289}
1290
1291void for_each_mergetag(each_mergetag_fn fn, struct commit *commit, void *data)
1292{
1293        struct commit_extra_header *extra, *to_free;
1294
1295        to_free = read_commit_extra_headers(commit, NULL);
1296        for (extra = to_free; extra; extra = extra->next) {
1297                if (strcmp(extra->key, "mergetag"))
1298                        continue; /* not a merge tag */
1299                fn(commit, extra, data);
1300        }
1301        free_commit_extra_headers(to_free);
1302}
1303
1304static inline int standard_header_field(const char *field, size_t len)
1305{
1306        return ((len == 4 && !memcmp(field, "tree ", 5)) ||
1307                (len == 6 && !memcmp(field, "parent ", 7)) ||
1308                (len == 6 && !memcmp(field, "author ", 7)) ||
1309                (len == 9 && !memcmp(field, "committer ", 10)) ||
1310                (len == 8 && !memcmp(field, "encoding ", 9)));
1311}
1312
1313static int excluded_header_field(const char *field, size_t len, const char **exclude)
1314{
1315        if (!exclude)
1316                return 0;
1317
1318        while (*exclude) {
1319                size_t xlen = strlen(*exclude);
1320                if (len == xlen &&
1321                    !memcmp(field, *exclude, xlen) && field[xlen] == ' ')
1322                        return 1;
1323                exclude++;
1324        }
1325        return 0;
1326}
1327
1328static struct commit_extra_header *read_commit_extra_header_lines(
1329        const char *buffer, size_t size,
1330        const char **exclude)
1331{
1332        struct commit_extra_header *extra = NULL, **tail = &extra, *it = NULL;
1333        const char *line, *next, *eof, *eob;
1334        struct strbuf buf = STRBUF_INIT;
1335
1336        for (line = buffer, eob = line + size;
1337             line < eob && *line != '\n';
1338             line = next) {
1339                next = memchr(line, '\n', eob - line);
1340                next = next ? next + 1 : eob;
1341                if (*line == ' ') {
1342                        /* continuation */
1343                        if (it)
1344                                strbuf_add(&buf, line + 1, next - (line + 1));
1345                        continue;
1346                }
1347                if (it)
1348                        it->value = strbuf_detach(&buf, &it->len);
1349                strbuf_reset(&buf);
1350                it = NULL;
1351
1352                eof = strchr(line, ' ');
1353                if (next <= eof)
1354                        eof = next;
1355
1356                if (standard_header_field(line, eof - line) ||
1357                    excluded_header_field(line, eof - line, exclude))
1358                        continue;
1359
1360                it = xcalloc(1, sizeof(*it));
1361                it->key = xmemdupz(line, eof-line);
1362                *tail = it;
1363                tail = &it->next;
1364                if (eof + 1 < next)
1365                        strbuf_add(&buf, eof + 1, next - (eof + 1));
1366        }
1367        if (it)
1368                it->value = strbuf_detach(&buf, &it->len);
1369        return extra;
1370}
1371
1372void free_commit_extra_headers(struct commit_extra_header *extra)
1373{
1374        while (extra) {
1375                struct commit_extra_header *next = extra->next;
1376                free(extra->key);
1377                free(extra->value);
1378                free(extra);
1379                extra = next;
1380        }
1381}
1382
1383int commit_tree(const char *msg, size_t msg_len,
1384                const unsigned char *tree,
1385                struct commit_list *parents, unsigned char *ret,
1386                const char *author, const char *sign_commit)
1387{
1388        struct commit_extra_header *extra = NULL, **tail = &extra;
1389        int result;
1390
1391        append_merge_tag_headers(parents, &tail);
1392        result = commit_tree_extended(msg, msg_len, tree, parents, ret,
1393                                      author, sign_commit, extra);
1394        free_commit_extra_headers(extra);
1395        return result;
1396}
1397
1398static int find_invalid_utf8(const char *buf, int len)
1399{
1400        int offset = 0;
1401        static const unsigned int max_codepoint[] = {
1402                0x7f, 0x7ff, 0xffff, 0x10ffff
1403        };
1404
1405        while (len) {
1406                unsigned char c = *buf++;
1407                int bytes, bad_offset;
1408                unsigned int codepoint;
1409                unsigned int min_val, max_val;
1410
1411                len--;
1412                offset++;
1413
1414                /* Simple US-ASCII? No worries. */
1415                if (c < 0x80)
1416                        continue;
1417
1418                bad_offset = offset-1;
1419
1420                /*
1421                 * Count how many more high bits set: that's how
1422                 * many more bytes this sequence should have.
1423                 */
1424                bytes = 0;
1425                while (c & 0x40) {
1426                        c <<= 1;
1427                        bytes++;
1428                }
1429
1430                /*
1431                 * Must be between 1 and 3 more bytes.  Longer sequences result in
1432                 * codepoints beyond U+10FFFF, which are guaranteed never to exist.
1433                 */
1434                if (bytes < 1 || 3 < bytes)
1435                        return bad_offset;
1436
1437                /* Do we *have* that many bytes? */
1438                if (len < bytes)
1439                        return bad_offset;
1440
1441                /*
1442                 * Place the encoded bits at the bottom of the value and compute the
1443                 * valid range.
1444                 */
1445                codepoint = (c & 0x7f) >> bytes;
1446                min_val = max_codepoint[bytes-1] + 1;
1447                max_val = max_codepoint[bytes];
1448
1449                offset += bytes;
1450                len -= bytes;
1451
1452                /* And verify that they are good continuation bytes */
1453                do {
1454                        codepoint <<= 6;
1455                        codepoint |= *buf & 0x3f;
1456                        if ((*buf++ & 0xc0) != 0x80)
1457                                return bad_offset;
1458                } while (--bytes);
1459
1460                /* Reject codepoints that are out of range for the sequence length. */
1461                if (codepoint < min_val || codepoint > max_val)
1462                        return bad_offset;
1463                /* Surrogates are only for UTF-16 and cannot be encoded in UTF-8. */
1464                if ((codepoint & 0x1ff800) == 0xd800)
1465                        return bad_offset;
1466                /* U+xxFFFE and U+xxFFFF are guaranteed non-characters. */
1467                if ((codepoint & 0xfffe) == 0xfffe)
1468                        return bad_offset;
1469                /* So are anything in the range U+FDD0..U+FDEF. */
1470                if (codepoint >= 0xfdd0 && codepoint <= 0xfdef)
1471                        return bad_offset;
1472        }
1473        return -1;
1474}
1475
1476/*
1477 * This verifies that the buffer is in proper utf8 format.
1478 *
1479 * If it isn't, it assumes any non-utf8 characters are Latin1,
1480 * and does the conversion.
1481 */
1482static int verify_utf8(struct strbuf *buf)
1483{
1484        int ok = 1;
1485        long pos = 0;
1486
1487        for (;;) {
1488                int bad;
1489                unsigned char c;
1490                unsigned char replace[2];
1491
1492                bad = find_invalid_utf8(buf->buf + pos, buf->len - pos);
1493                if (bad < 0)
1494                        return ok;
1495                pos += bad;
1496                ok = 0;
1497                c = buf->buf[pos];
1498                strbuf_remove(buf, pos, 1);
1499
1500                /* We know 'c' must be in the range 128-255 */
1501                replace[0] = 0xc0 + (c >> 6);
1502                replace[1] = 0x80 + (c & 0x3f);
1503                strbuf_insert(buf, pos, replace, 2);
1504                pos += 2;
1505        }
1506}
1507
1508static const char commit_utf8_warn[] =
1509"Warning: commit message did not conform to UTF-8.\n"
1510"You may want to amend it after fixing the message, or set the config\n"
1511"variable i18n.commitencoding to the encoding your project uses.\n";
1512
1513int commit_tree_extended(const char *msg, size_t msg_len,
1514                         const unsigned char *tree,
1515                         struct commit_list *parents, unsigned char *ret,
1516                         const char *author, const char *sign_commit,
1517                         struct commit_extra_header *extra)
1518{
1519        int result;
1520        int encoding_is_utf8;
1521        struct strbuf buffer;
1522
1523        assert_sha1_type(tree, OBJ_TREE);
1524
1525        if (memchr(msg, '\0', msg_len))
1526                return error("a NUL byte in commit log message not allowed.");
1527
1528        /* Not having i18n.commitencoding is the same as having utf-8 */
1529        encoding_is_utf8 = is_encoding_utf8(git_commit_encoding);
1530
1531        strbuf_init(&buffer, 8192); /* should avoid reallocs for the headers */
1532        strbuf_addf(&buffer, "tree %s\n", sha1_to_hex(tree));
1533
1534        /*
1535         * NOTE! This ordering means that the same exact tree merged with a
1536         * different order of parents will be a _different_ changeset even
1537         * if everything else stays the same.
1538         */
1539        while (parents) {
1540                struct commit_list *next = parents->next;
1541                struct commit *parent = parents->item;
1542
1543                strbuf_addf(&buffer, "parent %s\n",
1544                            sha1_to_hex(parent->object.sha1));
1545                free(parents);
1546                parents = next;
1547        }
1548
1549        /* Person/date information */
1550        if (!author)
1551                author = git_author_info(IDENT_STRICT);
1552        strbuf_addf(&buffer, "author %s\n", author);
1553        strbuf_addf(&buffer, "committer %s\n", git_committer_info(IDENT_STRICT));
1554        if (!encoding_is_utf8)
1555                strbuf_addf(&buffer, "encoding %s\n", git_commit_encoding);
1556
1557        while (extra) {
1558                add_extra_header(&buffer, extra);
1559                extra = extra->next;
1560        }
1561        strbuf_addch(&buffer, '\n');
1562
1563        /* And add the comment */
1564        strbuf_add(&buffer, msg, msg_len);
1565
1566        /* And check the encoding */
1567        if (encoding_is_utf8 && !verify_utf8(&buffer))
1568                fprintf(stderr, commit_utf8_warn);
1569
1570        if (sign_commit && do_sign_commit(&buffer, sign_commit))
1571                return -1;
1572
1573        result = write_sha1_file(buffer.buf, buffer.len, commit_type, ret);
1574        strbuf_release(&buffer);
1575        return result;
1576}
1577
1578struct commit *get_merge_parent(const char *name)
1579{
1580        struct object *obj;
1581        struct commit *commit;
1582        unsigned char sha1[20];
1583        if (get_sha1(name, sha1))
1584                return NULL;
1585        obj = parse_object(sha1);
1586        commit = (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
1587        if (commit && !commit->util) {
1588                struct merge_remote_desc *desc;
1589                desc = xmalloc(sizeof(*desc));
1590                desc->obj = obj;
1591                desc->name = strdup(name);
1592                commit->util = desc;
1593        }
1594        return commit;
1595}
1596
1597/*
1598 * Append a commit to the end of the commit_list.
1599 *
1600 * next starts by pointing to the variable that holds the head of an
1601 * empty commit_list, and is updated to point to the "next" field of
1602 * the last item on the list as new commits are appended.
1603 *
1604 * Usage example:
1605 *
1606 *     struct commit_list *list;
1607 *     struct commit_list **next = &list;
1608 *
1609 *     next = commit_list_append(c1, next);
1610 *     next = commit_list_append(c2, next);
1611 *     assert(commit_list_count(list) == 2);
1612 *     return list;
1613 */
1614struct commit_list **commit_list_append(struct commit *commit,
1615                                        struct commit_list **next)
1616{
1617        struct commit_list *new = xmalloc(sizeof(struct commit_list));
1618        new->item = commit;
1619        *next = new;
1620        new->next = NULL;
1621        return &new->next;
1622}
1623
1624void print_commit_list(struct commit_list *list,
1625                       const char *format_cur,
1626                       const char *format_last)
1627{
1628        for ( ; list; list = list->next) {
1629                const char *format = list->next ? format_cur : format_last;
1630                printf(format, sha1_to_hex(list->item->object.sha1));
1631        }
1632}