Andrew's git / gitweb.git / commit.c
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commit.con commit Merge branch 'sb/submodule-config-parse' (8b70042)
   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        struct object_id oid;
  59        struct commit *commit;
  60
  61        if (get_sha1_committish(name, oid.hash))
  62                return NULL;
  63        commit = lookup_commit_reference(oid.hash);
  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]->oid.hash;
 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->oid.hash);
 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        const int entry_size = GIT_SHA1_HEXSZ + 1;
 142
 143        while (len && isspace(buf[len-1]))
 144                buf[--len] = '\0';
 145        if (buf[0] == '#' || buf[0] == '\0')
 146                return NULL;
 147        if ((len + 1) % entry_size)
 148                goto bad_graft_data;
 149        i = (len + 1) / entry_size - 1;
 150        graft = xmalloc(sizeof(*graft) + GIT_SHA1_RAWSZ * i);
 151        graft->nr_parent = i;
 152        if (get_oid_hex(buf, &graft->oid))
 153                goto bad_graft_data;
 154        for (i = GIT_SHA1_HEXSZ; i < len; i += entry_size) {
 155                if (buf[i] != ' ')
 156                        goto bad_graft_data;
 157                if (get_sha1_hex(buf + i + 1, graft->parent[i/entry_size].hash))
 158                        goto bad_graft_data;
 159        }
 160        return graft;
 161
 162bad_graft_data:
 163        error("bad graft data: %s", buf);
 164        free(graft);
 165        return NULL;
 166}
 167
 168static int read_graft_file(const char *graft_file)
 169{
 170        FILE *fp = fopen(graft_file, "r");
 171        struct strbuf buf = STRBUF_INIT;
 172        if (!fp)
 173                return -1;
 174        while (!strbuf_getwholeline(&buf, fp, '\n')) {
 175                /* The format is just "Commit Parent1 Parent2 ...\n" */
 176                struct commit_graft *graft = read_graft_line(buf.buf, buf.len);
 177                if (!graft)
 178                        continue;
 179                if (register_commit_graft(graft, 1))
 180                        error("duplicate graft data: %s", buf.buf);
 181        }
 182        fclose(fp);
 183        strbuf_release(&buf);
 184        return 0;
 185}
 186
 187static void prepare_commit_graft(void)
 188{
 189        static int commit_graft_prepared;
 190        char *graft_file;
 191
 192        if (commit_graft_prepared)
 193                return;
 194        graft_file = get_graft_file();
 195        read_graft_file(graft_file);
 196        /* make sure shallows are read */
 197        is_repository_shallow();
 198        commit_graft_prepared = 1;
 199}
 200
 201struct commit_graft *lookup_commit_graft(const unsigned char *sha1)
 202{
 203        int pos;
 204        prepare_commit_graft();
 205        pos = commit_graft_pos(sha1);
 206        if (pos < 0)
 207                return NULL;
 208        return commit_graft[pos];
 209}
 210
 211int for_each_commit_graft(each_commit_graft_fn fn, void *cb_data)
 212{
 213        int i, ret;
 214        for (i = ret = 0; i < commit_graft_nr && !ret; i++)
 215                ret = fn(commit_graft[i], cb_data);
 216        return ret;
 217}
 218
 219int unregister_shallow(const unsigned char *sha1)
 220{
 221        int pos = commit_graft_pos(sha1);
 222        if (pos < 0)
 223                return -1;
 224        if (pos + 1 < commit_graft_nr)
 225                memmove(commit_graft + pos, commit_graft + pos + 1,
 226                                sizeof(struct commit_graft *)
 227                                * (commit_graft_nr - pos - 1));
 228        commit_graft_nr--;
 229        return 0;
 230}
 231
 232struct commit_buffer {
 233        void *buffer;
 234        unsigned long size;
 235};
 236define_commit_slab(buffer_slab, struct commit_buffer);
 237static struct buffer_slab buffer_slab = COMMIT_SLAB_INIT(1, buffer_slab);
 238
 239void set_commit_buffer(struct commit *commit, void *buffer, unsigned long size)
 240{
 241        struct commit_buffer *v = buffer_slab_at(&buffer_slab, commit);
 242        v->buffer = buffer;
 243        v->size = size;
 244}
 245
 246const void *get_cached_commit_buffer(const struct commit *commit, unsigned long *sizep)
 247{
 248        struct commit_buffer *v = buffer_slab_peek(&buffer_slab, commit);
 249        if (!v) {
 250                if (sizep)
 251                        *sizep = 0;
 252                return NULL;
 253        }
 254        if (sizep)
 255                *sizep = v->size;
 256        return v->buffer;
 257}
 258
 259const void *get_commit_buffer(const struct commit *commit, unsigned long *sizep)
 260{
 261        const void *ret = get_cached_commit_buffer(commit, sizep);
 262        if (!ret) {
 263                enum object_type type;
 264                unsigned long size;
 265                ret = read_sha1_file(commit->object.sha1, &type, &size);
 266                if (!ret)
 267                        die("cannot read commit object %s",
 268                            sha1_to_hex(commit->object.sha1));
 269                if (type != OBJ_COMMIT)
 270                        die("expected commit for %s, got %s",
 271                            sha1_to_hex(commit->object.sha1), typename(type));
 272                if (sizep)
 273                        *sizep = size;
 274        }
 275        return ret;
 276}
 277
 278void unuse_commit_buffer(const struct commit *commit, const void *buffer)
 279{
 280        struct commit_buffer *v = buffer_slab_peek(&buffer_slab, commit);
 281        if (!(v && v->buffer == buffer))
 282                free((void *)buffer);
 283}
 284
 285void free_commit_buffer(struct commit *commit)
 286{
 287        struct commit_buffer *v = buffer_slab_peek(&buffer_slab, commit);
 288        if (v) {
 289                free(v->buffer);
 290                v->buffer = NULL;
 291                v->size = 0;
 292        }
 293}
 294
 295const void *detach_commit_buffer(struct commit *commit, unsigned long *sizep)
 296{
 297        struct commit_buffer *v = buffer_slab_peek(&buffer_slab, commit);
 298        void *ret;
 299
 300        if (!v) {
 301                if (sizep)
 302                        *sizep = 0;
 303                return NULL;
 304        }
 305        ret = v->buffer;
 306        if (sizep)
 307                *sizep = v->size;
 308
 309        v->buffer = NULL;
 310        v->size = 0;
 311        return ret;
 312}
 313
 314int parse_commit_buffer(struct commit *item, const void *buffer, unsigned long size)
 315{
 316        const char *tail = buffer;
 317        const char *bufptr = buffer;
 318        struct object_id parent;
 319        struct commit_list **pptr;
 320        struct commit_graft *graft;
 321        const int tree_entry_len = GIT_SHA1_HEXSZ + 5;
 322        const int parent_entry_len = GIT_SHA1_HEXSZ + 7;
 323
 324        if (item->object.parsed)
 325                return 0;
 326        item->object.parsed = 1;
 327        tail += size;
 328        if (tail <= bufptr + tree_entry_len + 1 || memcmp(bufptr, "tree ", 5) ||
 329                        bufptr[tree_entry_len] != '\n')
 330                return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
 331        if (get_sha1_hex(bufptr + 5, parent.hash) < 0)
 332                return error("bad tree pointer in commit %s",
 333                             sha1_to_hex(item->object.sha1));
 334        item->tree = lookup_tree(parent.hash);
 335        bufptr += tree_entry_len + 1; /* "tree " + "hex sha1" + "\n" */
 336        pptr = &item->parents;
 337
 338        graft = lookup_commit_graft(item->object.sha1);
 339        while (bufptr + parent_entry_len < tail && !memcmp(bufptr, "parent ", 7)) {
 340                struct commit *new_parent;
 341
 342                if (tail <= bufptr + parent_entry_len + 1 ||
 343                    get_sha1_hex(bufptr + 7, parent.hash) ||
 344                    bufptr[parent_entry_len] != '\n')
 345                        return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
 346                bufptr += parent_entry_len + 1;
 347                /*
 348                 * The clone is shallow if nr_parent < 0, and we must
 349                 * not traverse its real parents even when we unhide them.
 350                 */
 351                if (graft && (graft->nr_parent < 0 || grafts_replace_parents))
 352                        continue;
 353                new_parent = lookup_commit(parent.hash);
 354                if (new_parent)
 355                        pptr = &commit_list_insert(new_parent, pptr)->next;
 356        }
 357        if (graft) {
 358                int i;
 359                struct commit *new_parent;
 360                for (i = 0; i < graft->nr_parent; i++) {
 361                        new_parent = lookup_commit(graft->parent[i].hash);
 362                        if (!new_parent)
 363                                continue;
 364                        pptr = &commit_list_insert(new_parent, pptr)->next;
 365                }
 366        }
 367        item->date = parse_commit_date(bufptr, tail);
 368
 369        return 0;
 370}
 371
 372int parse_commit_gently(struct commit *item, int quiet_on_missing)
 373{
 374        enum object_type type;
 375        void *buffer;
 376        unsigned long size;
 377        int ret;
 378
 379        if (!item)
 380                return -1;
 381        if (item->object.parsed)
 382                return 0;
 383        buffer = read_sha1_file(item->object.sha1, &type, &size);
 384        if (!buffer)
 385                return quiet_on_missing ? -1 :
 386                        error("Could not read %s",
 387                             sha1_to_hex(item->object.sha1));
 388        if (type != OBJ_COMMIT) {
 389                free(buffer);
 390                return error("Object %s not a commit",
 391                             sha1_to_hex(item->object.sha1));
 392        }
 393        ret = parse_commit_buffer(item, buffer, size);
 394        if (save_commit_buffer && !ret) {
 395                set_commit_buffer(item, buffer, size);
 396                return 0;
 397        }
 398        free(buffer);
 399        return ret;
 400}
 401
 402void parse_commit_or_die(struct commit *item)
 403{
 404        if (parse_commit(item))
 405                die("unable to parse commit %s",
 406                    item ? sha1_to_hex(item->object.sha1) : "(null)");
 407}
 408
 409int find_commit_subject(const char *commit_buffer, const char **subject)
 410{
 411        const char *eol;
 412        const char *p = commit_buffer;
 413
 414        while (*p && (*p != '\n' || p[1] != '\n'))
 415                p++;
 416        if (*p) {
 417                p += 2;
 418                for (eol = p; *eol && *eol != '\n'; eol++)
 419                        ; /* do nothing */
 420        } else
 421                eol = p;
 422
 423        *subject = p;
 424
 425        return eol - p;
 426}
 427
 428struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
 429{
 430        struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
 431        new_list->item = item;
 432        new_list->next = *list_p;
 433        *list_p = new_list;
 434        return new_list;
 435}
 436
 437unsigned commit_list_count(const struct commit_list *l)
 438{
 439        unsigned c = 0;
 440        for (; l; l = l->next )
 441                c++;
 442        return c;
 443}
 444
 445struct commit_list *copy_commit_list(struct commit_list *list)
 446{
 447        struct commit_list *head = NULL;
 448        struct commit_list **pp = &head;
 449        while (list) {
 450                pp = commit_list_append(list->item, pp);
 451                list = list->next;
 452        }
 453        return head;
 454}
 455
 456void free_commit_list(struct commit_list *list)
 457{
 458        while (list) {
 459                struct commit_list *temp = list;
 460                list = temp->next;
 461                free(temp);
 462        }
 463}
 464
 465struct commit_list * commit_list_insert_by_date(struct commit *item, struct commit_list **list)
 466{
 467        struct commit_list **pp = list;
 468        struct commit_list *p;
 469        while ((p = *pp) != NULL) {
 470                if (p->item->date < item->date) {
 471                        break;
 472                }
 473                pp = &p->next;
 474        }
 475        return commit_list_insert(item, pp);
 476}
 477
 478static int commit_list_compare_by_date(const void *a, const void *b)
 479{
 480        unsigned long a_date = ((const struct commit_list *)a)->item->date;
 481        unsigned long b_date = ((const struct commit_list *)b)->item->date;
 482        if (a_date < b_date)
 483                return 1;
 484        if (a_date > b_date)
 485                return -1;
 486        return 0;
 487}
 488
 489static void *commit_list_get_next(const void *a)
 490{
 491        return ((const struct commit_list *)a)->next;
 492}
 493
 494static void commit_list_set_next(void *a, void *next)
 495{
 496        ((struct commit_list *)a)->next = next;
 497}
 498
 499void commit_list_sort_by_date(struct commit_list **list)
 500{
 501        *list = llist_mergesort(*list, commit_list_get_next, commit_list_set_next,
 502                                commit_list_compare_by_date);
 503}
 504
 505struct commit *pop_most_recent_commit(struct commit_list **list,
 506                                      unsigned int mark)
 507{
 508        struct commit *ret = (*list)->item;
 509        struct commit_list *parents = ret->parents;
 510        struct commit_list *old = *list;
 511
 512        *list = (*list)->next;
 513        free(old);
 514
 515        while (parents) {
 516                struct commit *commit = parents->item;
 517                if (!parse_commit(commit) && !(commit->object.flags & mark)) {
 518                        commit->object.flags |= mark;
 519                        commit_list_insert_by_date(commit, list);
 520                }
 521                parents = parents->next;
 522        }
 523        return ret;
 524}
 525
 526static void clear_commit_marks_1(struct commit_list **plist,
 527                                 struct commit *commit, unsigned int mark)
 528{
 529        while (commit) {
 530                struct commit_list *parents;
 531
 532                if (!(mark & commit->object.flags))
 533                        return;
 534
 535                commit->object.flags &= ~mark;
 536
 537                parents = commit->parents;
 538                if (!parents)
 539                        return;
 540
 541                while ((parents = parents->next))
 542                        commit_list_insert(parents->item, plist);
 543
 544                commit = commit->parents->item;
 545        }
 546}
 547
 548void clear_commit_marks_many(int nr, struct commit **commit, unsigned int mark)
 549{
 550        struct commit_list *list = NULL;
 551
 552        while (nr--) {
 553                commit_list_insert(*commit, &list);
 554                commit++;
 555        }
 556        while (list)
 557                clear_commit_marks_1(&list, pop_commit(&list), mark);
 558}
 559
 560void clear_commit_marks(struct commit *commit, unsigned int mark)
 561{
 562        clear_commit_marks_many(1, &commit, mark);
 563}
 564
 565void clear_commit_marks_for_object_array(struct object_array *a, unsigned mark)
 566{
 567        struct object *object;
 568        struct commit *commit;
 569        unsigned int i;
 570
 571        for (i = 0; i < a->nr; i++) {
 572                object = a->objects[i].item;
 573                commit = lookup_commit_reference_gently(object->sha1, 1);
 574                if (commit)
 575                        clear_commit_marks(commit, mark);
 576        }
 577}
 578
 579struct commit *pop_commit(struct commit_list **stack)
 580{
 581        struct commit_list *top = *stack;
 582        struct commit *item = top ? top->item : NULL;
 583
 584        if (top) {
 585                *stack = top->next;
 586                free(top);
 587        }
 588        return item;
 589}
 590
 591/*
 592 * Topological sort support
 593 */
 594
 595/* count number of children that have not been emitted */
 596define_commit_slab(indegree_slab, int);
 597
 598/* record author-date for each commit object */
 599define_commit_slab(author_date_slab, unsigned long);
 600
 601static void record_author_date(struct author_date_slab *author_date,
 602                               struct commit *commit)
 603{
 604        const char *buffer = get_commit_buffer(commit, NULL);
 605        struct ident_split ident;
 606        const char *ident_line;
 607        size_t ident_len;
 608        char *date_end;
 609        unsigned long date;
 610
 611        ident_line = find_commit_header(buffer, "author", &ident_len);
 612        if (!ident_line)
 613                goto fail_exit; /* no author line */
 614        if (split_ident_line(&ident, ident_line, ident_len) ||
 615            !ident.date_begin || !ident.date_end)
 616                goto fail_exit; /* malformed "author" line */
 617
 618        date = strtoul(ident.date_begin, &date_end, 10);
 619        if (date_end != ident.date_end)
 620                goto fail_exit; /* malformed date */
 621        *(author_date_slab_at(author_date, commit)) = date;
 622
 623fail_exit:
 624        unuse_commit_buffer(commit, buffer);
 625}
 626
 627static int compare_commits_by_author_date(const void *a_, const void *b_,
 628                                          void *cb_data)
 629{
 630        const struct commit *a = a_, *b = b_;
 631        struct author_date_slab *author_date = cb_data;
 632        unsigned long a_date = *(author_date_slab_at(author_date, a));
 633        unsigned long b_date = *(author_date_slab_at(author_date, b));
 634
 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
 643int compare_commits_by_commit_date(const void *a_, const void *b_, void *unused)
 644{
 645        const struct commit *a = a_, *b = b_;
 646        /* newer commits with larger date first */
 647        if (a->date < b->date)
 648                return 1;
 649        else if (a->date > b->date)
 650                return -1;
 651        return 0;
 652}
 653
 654/*
 655 * Performs an in-place topological sort on the list supplied.
 656 */
 657void sort_in_topological_order(struct commit_list **list, enum rev_sort_order sort_order)
 658{
 659        struct commit_list *next, *orig = *list;
 660        struct commit_list **pptr;
 661        struct indegree_slab indegree;
 662        struct prio_queue queue;
 663        struct commit *commit;
 664        struct author_date_slab author_date;
 665
 666        if (!orig)
 667                return;
 668        *list = NULL;
 669
 670        init_indegree_slab(&indegree);
 671        memset(&queue, '\0', sizeof(queue));
 672
 673        switch (sort_order) {
 674        default: /* REV_SORT_IN_GRAPH_ORDER */
 675                queue.compare = NULL;
 676                break;
 677        case REV_SORT_BY_COMMIT_DATE:
 678                queue.compare = compare_commits_by_commit_date;
 679                break;
 680        case REV_SORT_BY_AUTHOR_DATE:
 681                init_author_date_slab(&author_date);
 682                queue.compare = compare_commits_by_author_date;
 683                queue.cb_data = &author_date;
 684                break;
 685        }
 686
 687        /* Mark them and clear the indegree */
 688        for (next = orig; next; next = next->next) {
 689                struct commit *commit = next->item;
 690                *(indegree_slab_at(&indegree, commit)) = 1;
 691                /* also record the author dates, if needed */
 692                if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 693                        record_author_date(&author_date, commit);
 694        }
 695
 696        /* update the indegree */
 697        for (next = orig; next; next = next->next) {
 698                struct commit_list *parents = next->item->parents;
 699                while (parents) {
 700                        struct commit *parent = parents->item;
 701                        int *pi = indegree_slab_at(&indegree, parent);
 702
 703                        if (*pi)
 704                                (*pi)++;
 705                        parents = parents->next;
 706                }
 707        }
 708
 709        /*
 710         * find the tips
 711         *
 712         * tips are nodes not reachable from any other node in the list
 713         *
 714         * the tips serve as a starting set for the work queue.
 715         */
 716        for (next = orig; next; next = next->next) {
 717                struct commit *commit = next->item;
 718
 719                if (*(indegree_slab_at(&indegree, commit)) == 1)
 720                        prio_queue_put(&queue, commit);
 721        }
 722
 723        /*
 724         * This is unfortunate; the initial tips need to be shown
 725         * in the order given from the revision traversal machinery.
 726         */
 727        if (sort_order == REV_SORT_IN_GRAPH_ORDER)
 728                prio_queue_reverse(&queue);
 729
 730        /* We no longer need the commit list */
 731        free_commit_list(orig);
 732
 733        pptr = list;
 734        *list = NULL;
 735        while ((commit = prio_queue_get(&queue)) != NULL) {
 736                struct commit_list *parents;
 737
 738                for (parents = commit->parents; parents ; parents = parents->next) {
 739                        struct commit *parent = parents->item;
 740                        int *pi = indegree_slab_at(&indegree, parent);
 741
 742                        if (!*pi)
 743                                continue;
 744
 745                        /*
 746                         * parents are only enqueued for emission
 747                         * when all their children have been emitted thereby
 748                         * guaranteeing topological order.
 749                         */
 750                        if (--(*pi) == 1)
 751                                prio_queue_put(&queue, parent);
 752                }
 753                /*
 754                 * all children of commit have already been
 755                 * emitted. we can emit it now.
 756                 */
 757                *(indegree_slab_at(&indegree, commit)) = 0;
 758
 759                pptr = &commit_list_insert(commit, pptr)->next;
 760        }
 761
 762        clear_indegree_slab(&indegree);
 763        clear_prio_queue(&queue);
 764        if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 765                clear_author_date_slab(&author_date);
 766}
 767
 768/* merge-base stuff */
 769
 770/* Remember to update object flag allocation in object.h */
 771#define PARENT1         (1u<<16)
 772#define PARENT2         (1u<<17)
 773#define STALE           (1u<<18)
 774#define RESULT          (1u<<19)
 775
 776static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
 777
 778static int queue_has_nonstale(struct prio_queue *queue)
 779{
 780        int i;
 781        for (i = 0; i < queue->nr; i++) {
 782                struct commit *commit = queue->array[i].data;
 783                if (!(commit->object.flags & STALE))
 784                        return 1;
 785        }
 786        return 0;
 787}
 788
 789/* all input commits in one and twos[] must have been parsed! */
 790static struct commit_list *paint_down_to_common(struct commit *one, int n, struct commit **twos)
 791{
 792        struct prio_queue queue = { compare_commits_by_commit_date };
 793        struct commit_list *result = NULL;
 794        int i;
 795
 796        one->object.flags |= PARENT1;
 797        if (!n) {
 798                commit_list_append(one, &result);
 799                return result;
 800        }
 801        prio_queue_put(&queue, one);
 802
 803        for (i = 0; i < n; i++) {
 804                twos[i]->object.flags |= PARENT2;
 805                prio_queue_put(&queue, twos[i]);
 806        }
 807
 808        while (queue_has_nonstale(&queue)) {
 809                struct commit *commit = prio_queue_get(&queue);
 810                struct commit_list *parents;
 811                int flags;
 812
 813                flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
 814                if (flags == (PARENT1 | PARENT2)) {
 815                        if (!(commit->object.flags & RESULT)) {
 816                                commit->object.flags |= RESULT;
 817                                commit_list_insert_by_date(commit, &result);
 818                        }
 819                        /* Mark parents of a found merge stale */
 820                        flags |= STALE;
 821                }
 822                parents = commit->parents;
 823                while (parents) {
 824                        struct commit *p = parents->item;
 825                        parents = parents->next;
 826                        if ((p->object.flags & flags) == flags)
 827                                continue;
 828                        if (parse_commit(p))
 829                                return NULL;
 830                        p->object.flags |= flags;
 831                        prio_queue_put(&queue, p);
 832                }
 833        }
 834
 835        clear_prio_queue(&queue);
 836        return result;
 837}
 838
 839static struct commit_list *merge_bases_many(struct commit *one, int n, struct commit **twos)
 840{
 841        struct commit_list *list = NULL;
 842        struct commit_list *result = NULL;
 843        int i;
 844
 845        for (i = 0; i < n; i++) {
 846                if (one == twos[i])
 847                        /*
 848                         * We do not mark this even with RESULT so we do not
 849                         * have to clean it up.
 850                         */
 851                        return commit_list_insert(one, &result);
 852        }
 853
 854        if (parse_commit(one))
 855                return NULL;
 856        for (i = 0; i < n; i++) {
 857                if (parse_commit(twos[i]))
 858                        return NULL;
 859        }
 860
 861        list = paint_down_to_common(one, n, twos);
 862
 863        while (list) {
 864                struct commit_list *next = list->next;
 865                if (!(list->item->object.flags & STALE))
 866                        commit_list_insert_by_date(list->item, &result);
 867                free(list);
 868                list = next;
 869        }
 870        return result;
 871}
 872
 873struct commit_list *get_octopus_merge_bases(struct commit_list *in)
 874{
 875        struct commit_list *i, *j, *k, *ret = NULL;
 876
 877        if (!in)
 878                return ret;
 879
 880        commit_list_insert(in->item, &ret);
 881
 882        for (i = in->next; i; i = i->next) {
 883                struct commit_list *new = NULL, *end = NULL;
 884
 885                for (j = ret; j; j = j->next) {
 886                        struct commit_list *bases;
 887                        bases = get_merge_bases(i->item, j->item);
 888                        if (!new)
 889                                new = bases;
 890                        else
 891                                end->next = bases;
 892                        for (k = bases; k; k = k->next)
 893                                end = k;
 894                }
 895                ret = new;
 896        }
 897        return ret;
 898}
 899
 900static int remove_redundant(struct commit **array, int cnt)
 901{
 902        /*
 903         * Some commit in the array may be an ancestor of
 904         * another commit.  Move such commit to the end of
 905         * the array, and return the number of commits that
 906         * are independent from each other.
 907         */
 908        struct commit **work;
 909        unsigned char *redundant;
 910        int *filled_index;
 911        int i, j, filled;
 912
 913        work = xcalloc(cnt, sizeof(*work));
 914        redundant = xcalloc(cnt, 1);
 915        filled_index = xmalloc(sizeof(*filled_index) * (cnt - 1));
 916
 917        for (i = 0; i < cnt; i++)
 918                parse_commit(array[i]);
 919        for (i = 0; i < cnt; i++) {
 920                struct commit_list *common;
 921
 922                if (redundant[i])
 923                        continue;
 924                for (j = filled = 0; j < cnt; j++) {
 925                        if (i == j || redundant[j])
 926                                continue;
 927                        filled_index[filled] = j;
 928                        work[filled++] = array[j];
 929                }
 930                common = paint_down_to_common(array[i], filled, work);
 931                if (array[i]->object.flags & PARENT2)
 932                        redundant[i] = 1;
 933                for (j = 0; j < filled; j++)
 934                        if (work[j]->object.flags & PARENT1)
 935                                redundant[filled_index[j]] = 1;
 936                clear_commit_marks(array[i], all_flags);
 937                for (j = 0; j < filled; j++)
 938                        clear_commit_marks(work[j], all_flags);
 939                free_commit_list(common);
 940        }
 941
 942        /* Now collect the result */
 943        memcpy(work, array, sizeof(*array) * cnt);
 944        for (i = filled = 0; i < cnt; i++)
 945                if (!redundant[i])
 946                        array[filled++] = work[i];
 947        for (j = filled, i = 0; i < cnt; i++)
 948                if (redundant[i])
 949                        array[j++] = work[i];
 950        free(work);
 951        free(redundant);
 952        free(filled_index);
 953        return filled;
 954}
 955
 956static struct commit_list *get_merge_bases_many_0(struct commit *one,
 957                                                  int n,
 958                                                  struct commit **twos,
 959                                                  int cleanup)
 960{
 961        struct commit_list *list;
 962        struct commit **rslt;
 963        struct commit_list *result;
 964        int cnt, i;
 965
 966        result = merge_bases_many(one, n, twos);
 967        for (i = 0; i < n; i++) {
 968                if (one == twos[i])
 969                        return result;
 970        }
 971        if (!result || !result->next) {
 972                if (cleanup) {
 973                        clear_commit_marks(one, all_flags);
 974                        clear_commit_marks_many(n, twos, all_flags);
 975                }
 976                return result;
 977        }
 978
 979        /* There are more than one */
 980        cnt = commit_list_count(result);
 981        rslt = xcalloc(cnt, sizeof(*rslt));
 982        for (list = result, i = 0; list; list = list->next)
 983                rslt[i++] = list->item;
 984        free_commit_list(result);
 985
 986        clear_commit_marks(one, all_flags);
 987        clear_commit_marks_many(n, twos, all_flags);
 988
 989        cnt = remove_redundant(rslt, cnt);
 990        result = NULL;
 991        for (i = 0; i < cnt; i++)
 992                commit_list_insert_by_date(rslt[i], &result);
 993        free(rslt);
 994        return result;
 995}
 996
 997struct commit_list *get_merge_bases_many(struct commit *one,
 998                                         int n,
 999                                         struct commit **twos)
1000{
1001        return get_merge_bases_many_0(one, n, twos, 1);
1002}
1003
1004struct commit_list *get_merge_bases_many_dirty(struct commit *one,
1005                                               int n,
1006                                               struct commit **twos)
1007{
1008        return get_merge_bases_many_0(one, n, twos, 0);
1009}
1010
1011struct commit_list *get_merge_bases(struct commit *one, struct commit *two)
1012{
1013        return get_merge_bases_many_0(one, 1, &two, 1);
1014}
1015
1016/*
1017 * Is "commit" a descendant of one of the elements on the "with_commit" list?
1018 */
1019int is_descendant_of(struct commit *commit, struct commit_list *with_commit)
1020{
1021        if (!with_commit)
1022                return 1;
1023        while (with_commit) {
1024                struct commit *other;
1025
1026                other = with_commit->item;
1027                with_commit = with_commit->next;
1028                if (in_merge_bases(other, commit))
1029                        return 1;
1030        }
1031        return 0;
1032}
1033
1034/*
1035 * Is "commit" an ancestor of one of the "references"?
1036 */
1037int in_merge_bases_many(struct commit *commit, int nr_reference, struct commit **reference)
1038{
1039        struct commit_list *bases;
1040        int ret = 0, i;
1041
1042        if (parse_commit(commit))
1043                return ret;
1044        for (i = 0; i < nr_reference; i++)
1045                if (parse_commit(reference[i]))
1046                        return ret;
1047
1048        bases = paint_down_to_common(commit, nr_reference, reference);
1049        if (commit->object.flags & PARENT2)
1050                ret = 1;
1051        clear_commit_marks(commit, all_flags);
1052        clear_commit_marks_many(nr_reference, reference, all_flags);
1053        free_commit_list(bases);
1054        return ret;
1055}
1056
1057/*
1058 * Is "commit" an ancestor of (i.e. reachable from) the "reference"?
1059 */
1060int in_merge_bases(struct commit *commit, struct commit *reference)
1061{
1062        return in_merge_bases_many(commit, 1, &reference);
1063}
1064
1065struct commit_list *reduce_heads(struct commit_list *heads)
1066{
1067        struct commit_list *p;
1068        struct commit_list *result = NULL, **tail = &result;
1069        struct commit **array;
1070        int num_head, i;
1071
1072        if (!heads)
1073                return NULL;
1074
1075        /* Uniquify */
1076        for (p = heads; p; p = p->next)
1077                p->item->object.flags &= ~STALE;
1078        for (p = heads, num_head = 0; p; p = p->next) {
1079                if (p->item->object.flags & STALE)
1080                        continue;
1081                p->item->object.flags |= STALE;
1082                num_head++;
1083        }
1084        array = xcalloc(num_head, sizeof(*array));
1085        for (p = heads, i = 0; p; p = p->next) {
1086                if (p->item->object.flags & STALE) {
1087                        array[i++] = p->item;
1088                        p->item->object.flags &= ~STALE;
1089                }
1090        }
1091        num_head = remove_redundant(array, num_head);
1092        for (i = 0; i < num_head; i++)
1093                tail = &commit_list_insert(array[i], tail)->next;
1094        return result;
1095}
1096
1097static const char gpg_sig_header[] = "gpgsig";
1098static const int gpg_sig_header_len = sizeof(gpg_sig_header) - 1;
1099
1100static int do_sign_commit(struct strbuf *buf, const char *keyid)
1101{
1102        struct strbuf sig = STRBUF_INIT;
1103        int inspos, copypos;
1104
1105        /* find the end of the header */
1106        inspos = strstr(buf->buf, "\n\n") - buf->buf + 1;
1107
1108        if (!keyid || !*keyid)
1109                keyid = get_signing_key();
1110        if (sign_buffer(buf, &sig, keyid)) {
1111                strbuf_release(&sig);
1112                return -1;
1113        }
1114
1115        for (copypos = 0; sig.buf[copypos]; ) {
1116                const char *bol = sig.buf + copypos;
1117                const char *eol = strchrnul(bol, '\n');
1118                int len = (eol - bol) + !!*eol;
1119
1120                if (!copypos) {
1121                        strbuf_insert(buf, inspos, gpg_sig_header, gpg_sig_header_len);
1122                        inspos += gpg_sig_header_len;
1123                }
1124                strbuf_insert(buf, inspos++, " ", 1);
1125                strbuf_insert(buf, inspos, bol, len);
1126                inspos += len;
1127                copypos += len;
1128        }
1129        strbuf_release(&sig);
1130        return 0;
1131}
1132
1133int parse_signed_commit(const struct commit *commit,
1134                        struct strbuf *payload, struct strbuf *signature)
1135{
1136
1137        unsigned long size;
1138        const char *buffer = get_commit_buffer(commit, &size);
1139        int in_signature, saw_signature = -1;
1140        const char *line, *tail;
1141
1142        line = buffer;
1143        tail = buffer + size;
1144        in_signature = 0;
1145        saw_signature = 0;
1146        while (line < tail) {
1147                const char *sig = NULL;
1148                const char *next = memchr(line, '\n', tail - line);
1149
1150                next = next ? next + 1 : tail;
1151                if (in_signature && line[0] == ' ')
1152                        sig = line + 1;
1153                else if (starts_with(line, gpg_sig_header) &&
1154                         line[gpg_sig_header_len] == ' ')
1155                        sig = line + gpg_sig_header_len + 1;
1156                if (sig) {
1157                        strbuf_add(signature, sig, next - sig);
1158                        saw_signature = 1;
1159                        in_signature = 1;
1160                } else {
1161                        if (*line == '\n')
1162                                /* dump the whole remainder of the buffer */
1163                                next = tail;
1164                        strbuf_add(payload, line, next - line);
1165                        in_signature = 0;
1166                }
1167                line = next;
1168        }
1169        unuse_commit_buffer(commit, buffer);
1170        return saw_signature;
1171}
1172
1173int remove_signature(struct strbuf *buf)
1174{
1175        const char *line = buf->buf;
1176        const char *tail = buf->buf + buf->len;
1177        int in_signature = 0;
1178        const char *sig_start = NULL;
1179        const char *sig_end = NULL;
1180
1181        while (line < tail) {
1182                const char *next = memchr(line, '\n', tail - line);
1183                next = next ? next + 1 : tail;
1184
1185                if (in_signature && line[0] == ' ')
1186                        sig_end = next;
1187                else if (starts_with(line, gpg_sig_header) &&
1188                         line[gpg_sig_header_len] == ' ') {
1189                        sig_start = line;
1190                        sig_end = next;
1191                        in_signature = 1;
1192                } else {
1193                        if (*line == '\n')
1194                                /* dump the whole remainder of the buffer */
1195                                next = tail;
1196                        in_signature = 0;
1197                }
1198                line = next;
1199        }
1200
1201        if (sig_start)
1202                strbuf_remove(buf, sig_start - buf->buf, sig_end - sig_start);
1203
1204        return sig_start != NULL;
1205}
1206
1207static void handle_signed_tag(struct commit *parent, struct commit_extra_header ***tail)
1208{
1209        struct merge_remote_desc *desc;
1210        struct commit_extra_header *mergetag;
1211        char *buf;
1212        unsigned long size, len;
1213        enum object_type type;
1214
1215        desc = merge_remote_util(parent);
1216        if (!desc || !desc->obj)
1217                return;
1218        buf = read_sha1_file(desc->obj->sha1, &type, &size);
1219        if (!buf || type != OBJ_TAG)
1220                goto free_return;
1221        len = parse_signature(buf, size);
1222        if (size == len)
1223                goto free_return;
1224        /*
1225         * We could verify this signature and either omit the tag when
1226         * it does not validate, but the integrator may not have the
1227         * public key of the signer of the tag he is merging, while a
1228         * later auditor may have it while auditing, so let's not run
1229         * verify-signed-buffer here for now...
1230         *
1231         * if (verify_signed_buffer(buf, len, buf + len, size - len, ...))
1232         *      warn("warning: signed tag unverified.");
1233         */
1234        mergetag = xcalloc(1, sizeof(*mergetag));
1235        mergetag->key = xstrdup("mergetag");
1236        mergetag->value = buf;
1237        mergetag->len = size;
1238
1239        **tail = mergetag;
1240        *tail = &mergetag->next;
1241        return;
1242
1243free_return:
1244        free(buf);
1245}
1246
1247int check_commit_signature(const struct commit *commit, struct signature_check *sigc)
1248{
1249        struct strbuf payload = STRBUF_INIT;
1250        struct strbuf signature = STRBUF_INIT;
1251        int ret = 1;
1252
1253        sigc->result = 'N';
1254
1255        if (parse_signed_commit(commit, &payload, &signature) <= 0)
1256                goto out;
1257        ret = check_signature(payload.buf, payload.len, signature.buf,
1258                signature.len, sigc);
1259
1260 out:
1261        strbuf_release(&payload);
1262        strbuf_release(&signature);
1263
1264        return ret;
1265}
1266
1267
1268
1269void append_merge_tag_headers(struct commit_list *parents,
1270                              struct commit_extra_header ***tail)
1271{
1272        while (parents) {
1273                struct commit *parent = parents->item;
1274                handle_signed_tag(parent, tail);
1275                parents = parents->next;
1276        }
1277}
1278
1279static void add_extra_header(struct strbuf *buffer,
1280                             struct commit_extra_header *extra)
1281{
1282        strbuf_addstr(buffer, extra->key);
1283        if (extra->len)
1284                strbuf_add_lines(buffer, " ", extra->value, extra->len);
1285        else
1286                strbuf_addch(buffer, '\n');
1287}
1288
1289struct commit_extra_header *read_commit_extra_headers(struct commit *commit,
1290                                                      const char **exclude)
1291{
1292        struct commit_extra_header *extra = NULL;
1293        unsigned long size;
1294        const char *buffer = get_commit_buffer(commit, &size);
1295        extra = read_commit_extra_header_lines(buffer, size, exclude);
1296        unuse_commit_buffer(commit, buffer);
1297        return extra;
1298}
1299
1300void for_each_mergetag(each_mergetag_fn fn, struct commit *commit, void *data)
1301{
1302        struct commit_extra_header *extra, *to_free;
1303
1304        to_free = read_commit_extra_headers(commit, NULL);
1305        for (extra = to_free; extra; extra = extra->next) {
1306                if (strcmp(extra->key, "mergetag"))
1307                        continue; /* not a merge tag */
1308                fn(commit, extra, data);
1309        }
1310        free_commit_extra_headers(to_free);
1311}
1312
1313static inline int standard_header_field(const char *field, size_t len)
1314{
1315        return ((len == 4 && !memcmp(field, "tree ", 5)) ||
1316                (len == 6 && !memcmp(field, "parent ", 7)) ||
1317                (len == 6 && !memcmp(field, "author ", 7)) ||
1318                (len == 9 && !memcmp(field, "committer ", 10)) ||
1319                (len == 8 && !memcmp(field, "encoding ", 9)));
1320}
1321
1322static int excluded_header_field(const char *field, size_t len, const char **exclude)
1323{
1324        if (!exclude)
1325                return 0;
1326
1327        while (*exclude) {
1328                size_t xlen = strlen(*exclude);
1329                if (len == xlen &&
1330                    !memcmp(field, *exclude, xlen) && field[xlen] == ' ')
1331                        return 1;
1332                exclude++;
1333        }
1334        return 0;
1335}
1336
1337static struct commit_extra_header *read_commit_extra_header_lines(
1338        const char *buffer, size_t size,
1339        const char **exclude)
1340{
1341        struct commit_extra_header *extra = NULL, **tail = &extra, *it = NULL;
1342        const char *line, *next, *eof, *eob;
1343        struct strbuf buf = STRBUF_INIT;
1344
1345        for (line = buffer, eob = line + size;
1346             line < eob && *line != '\n';
1347             line = next) {
1348                next = memchr(line, '\n', eob - line);
1349                next = next ? next + 1 : eob;
1350                if (*line == ' ') {
1351                        /* continuation */
1352                        if (it)
1353                                strbuf_add(&buf, line + 1, next - (line + 1));
1354                        continue;
1355                }
1356                if (it)
1357                        it->value = strbuf_detach(&buf, &it->len);
1358                strbuf_reset(&buf);
1359                it = NULL;
1360
1361                eof = strchr(line, ' ');
1362                if (next <= eof)
1363                        eof = next;
1364
1365                if (standard_header_field(line, eof - line) ||
1366                    excluded_header_field(line, eof - line, exclude))
1367                        continue;
1368
1369                it = xcalloc(1, sizeof(*it));
1370                it->key = xmemdupz(line, eof-line);
1371                *tail = it;
1372                tail = &it->next;
1373                if (eof + 1 < next)
1374                        strbuf_add(&buf, eof + 1, next - (eof + 1));
1375        }
1376        if (it)
1377                it->value = strbuf_detach(&buf, &it->len);
1378        return extra;
1379}
1380
1381void free_commit_extra_headers(struct commit_extra_header *extra)
1382{
1383        while (extra) {
1384                struct commit_extra_header *next = extra->next;
1385                free(extra->key);
1386                free(extra->value);
1387                free(extra);
1388                extra = next;
1389        }
1390}
1391
1392int commit_tree(const char *msg, size_t msg_len,
1393                const unsigned char *tree,
1394                struct commit_list *parents, unsigned char *ret,
1395                const char *author, const char *sign_commit)
1396{
1397        struct commit_extra_header *extra = NULL, **tail = &extra;
1398        int result;
1399
1400        append_merge_tag_headers(parents, &tail);
1401        result = commit_tree_extended(msg, msg_len, tree, parents, ret,
1402                                      author, sign_commit, extra);
1403        free_commit_extra_headers(extra);
1404        return result;
1405}
1406
1407static int find_invalid_utf8(const char *buf, int len)
1408{
1409        int offset = 0;
1410        static const unsigned int max_codepoint[] = {
1411                0x7f, 0x7ff, 0xffff, 0x10ffff
1412        };
1413
1414        while (len) {
1415                unsigned char c = *buf++;
1416                int bytes, bad_offset;
1417                unsigned int codepoint;
1418                unsigned int min_val, max_val;
1419
1420                len--;
1421                offset++;
1422
1423                /* Simple US-ASCII? No worries. */
1424                if (c < 0x80)
1425                        continue;
1426
1427                bad_offset = offset-1;
1428
1429                /*
1430                 * Count how many more high bits set: that's how
1431                 * many more bytes this sequence should have.
1432                 */
1433                bytes = 0;
1434                while (c & 0x40) {
1435                        c <<= 1;
1436                        bytes++;
1437                }
1438
1439                /*
1440                 * Must be between 1 and 3 more bytes.  Longer sequences result in
1441                 * codepoints beyond U+10FFFF, which are guaranteed never to exist.
1442                 */
1443                if (bytes < 1 || 3 < bytes)
1444                        return bad_offset;
1445
1446                /* Do we *have* that many bytes? */
1447                if (len < bytes)
1448                        return bad_offset;
1449
1450                /*
1451                 * Place the encoded bits at the bottom of the value and compute the
1452                 * valid range.
1453                 */
1454                codepoint = (c & 0x7f) >> bytes;
1455                min_val = max_codepoint[bytes-1] + 1;
1456                max_val = max_codepoint[bytes];
1457
1458                offset += bytes;
1459                len -= bytes;
1460
1461                /* And verify that they are good continuation bytes */
1462                do {
1463                        codepoint <<= 6;
1464                        codepoint |= *buf & 0x3f;
1465                        if ((*buf++ & 0xc0) != 0x80)
1466                                return bad_offset;
1467                } while (--bytes);
1468
1469                /* Reject codepoints that are out of range for the sequence length. */
1470                if (codepoint < min_val || codepoint > max_val)
1471                        return bad_offset;
1472                /* Surrogates are only for UTF-16 and cannot be encoded in UTF-8. */
1473                if ((codepoint & 0x1ff800) == 0xd800)
1474                        return bad_offset;
1475                /* U+xxFFFE and U+xxFFFF are guaranteed non-characters. */
1476                if ((codepoint & 0xfffe) == 0xfffe)
1477                        return bad_offset;
1478                /* So are anything in the range U+FDD0..U+FDEF. */
1479                if (codepoint >= 0xfdd0 && codepoint <= 0xfdef)
1480                        return bad_offset;
1481        }
1482        return -1;
1483}
1484
1485/*
1486 * This verifies that the buffer is in proper utf8 format.
1487 *
1488 * If it isn't, it assumes any non-utf8 characters are Latin1,
1489 * and does the conversion.
1490 */
1491static int verify_utf8(struct strbuf *buf)
1492{
1493        int ok = 1;
1494        long pos = 0;
1495
1496        for (;;) {
1497                int bad;
1498                unsigned char c;
1499                unsigned char replace[2];
1500
1501                bad = find_invalid_utf8(buf->buf + pos, buf->len - pos);
1502                if (bad < 0)
1503                        return ok;
1504                pos += bad;
1505                ok = 0;
1506                c = buf->buf[pos];
1507                strbuf_remove(buf, pos, 1);
1508
1509                /* We know 'c' must be in the range 128-255 */
1510                replace[0] = 0xc0 + (c >> 6);
1511                replace[1] = 0x80 + (c & 0x3f);
1512                strbuf_insert(buf, pos, replace, 2);
1513                pos += 2;
1514        }
1515}
1516
1517static const char commit_utf8_warn[] =
1518"Warning: commit message did not conform to UTF-8.\n"
1519"You may want to amend it after fixing the message, or set the config\n"
1520"variable i18n.commitencoding to the encoding your project uses.\n";
1521
1522int commit_tree_extended(const char *msg, size_t msg_len,
1523                         const unsigned char *tree,
1524                         struct commit_list *parents, unsigned char *ret,
1525                         const char *author, const char *sign_commit,
1526                         struct commit_extra_header *extra)
1527{
1528        int result;
1529        int encoding_is_utf8;
1530        struct strbuf buffer;
1531
1532        assert_sha1_type(tree, OBJ_TREE);
1533
1534        if (memchr(msg, '\0', msg_len))
1535                return error("a NUL byte in commit log message not allowed.");
1536
1537        /* Not having i18n.commitencoding is the same as having utf-8 */
1538        encoding_is_utf8 = is_encoding_utf8(git_commit_encoding);
1539
1540        strbuf_init(&buffer, 8192); /* should avoid reallocs for the headers */
1541        strbuf_addf(&buffer, "tree %s\n", sha1_to_hex(tree));
1542
1543        /*
1544         * NOTE! This ordering means that the same exact tree merged with a
1545         * different order of parents will be a _different_ changeset even
1546         * if everything else stays the same.
1547         */
1548        while (parents) {
1549                struct commit_list *next = parents->next;
1550                struct commit *parent = parents->item;
1551
1552                strbuf_addf(&buffer, "parent %s\n",
1553                            sha1_to_hex(parent->object.sha1));
1554                free(parents);
1555                parents = next;
1556        }
1557
1558        /* Person/date information */
1559        if (!author)
1560                author = git_author_info(IDENT_STRICT);
1561        strbuf_addf(&buffer, "author %s\n", author);
1562        strbuf_addf(&buffer, "committer %s\n", git_committer_info(IDENT_STRICT));
1563        if (!encoding_is_utf8)
1564                strbuf_addf(&buffer, "encoding %s\n", git_commit_encoding);
1565
1566        while (extra) {
1567                add_extra_header(&buffer, extra);
1568                extra = extra->next;
1569        }
1570        strbuf_addch(&buffer, '\n');
1571
1572        /* And add the comment */
1573        strbuf_add(&buffer, msg, msg_len);
1574
1575        /* And check the encoding */
1576        if (encoding_is_utf8 && !verify_utf8(&buffer))
1577                fprintf(stderr, commit_utf8_warn);
1578
1579        if (sign_commit && do_sign_commit(&buffer, sign_commit))
1580                return -1;
1581
1582        result = write_sha1_file(buffer.buf, buffer.len, commit_type, ret);
1583        strbuf_release(&buffer);
1584        return result;
1585}
1586
1587struct commit *get_merge_parent(const char *name)
1588{
1589        struct object *obj;
1590        struct commit *commit;
1591        struct object_id oid;
1592        if (get_sha1(name, oid.hash))
1593                return NULL;
1594        obj = parse_object(oid.hash);
1595        commit = (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
1596        if (commit && !commit->util) {
1597                struct merge_remote_desc *desc;
1598                desc = xmalloc(sizeof(*desc));
1599                desc->obj = obj;
1600                desc->name = strdup(name);
1601                commit->util = desc;
1602        }
1603        return commit;
1604}
1605
1606/*
1607 * Append a commit to the end of the commit_list.
1608 *
1609 * next starts by pointing to the variable that holds the head of an
1610 * empty commit_list, and is updated to point to the "next" field of
1611 * the last item on the list as new commits are appended.
1612 *
1613 * Usage example:
1614 *
1615 *     struct commit_list *list;
1616 *     struct commit_list **next = &list;
1617 *
1618 *     next = commit_list_append(c1, next);
1619 *     next = commit_list_append(c2, next);
1620 *     assert(commit_list_count(list) == 2);
1621 *     return list;
1622 */
1623struct commit_list **commit_list_append(struct commit *commit,
1624                                        struct commit_list **next)
1625{
1626        struct commit_list *new = xmalloc(sizeof(struct commit_list));
1627        new->item = commit;
1628        *next = new;
1629        new->next = NULL;
1630        return &new->next;
1631}
1632
1633void print_commit_list(struct commit_list *list,
1634                       const char *format_cur,
1635                       const char *format_last)
1636{
1637        for ( ; list; list = list->next) {
1638                const char *format = list->next ? format_cur : format_last;
1639                printf(format, sha1_to_hex(list->item->object.sha1));
1640        }
1641}
1642
1643const char *find_commit_header(const char *msg, const char *key, size_t *out_len)
1644{
1645        int key_len = strlen(key);
1646        const char *line = msg;
1647
1648        while (line) {
1649                const char *eol = strchrnul(line, '\n');
1650
1651                if (line == eol)
1652                        return NULL;
1653
1654                if (eol - line > key_len &&
1655                    !strncmp(line, key, key_len) &&
1656                    line[key_len] == ' ') {
1657                        *out_len = eol - line - key_len - 1;
1658                        return line + key_len + 1;
1659                }
1660                line = *eol ? eol + 1 : NULL;
1661        }
1662        return NULL;
1663}
1664
1665/*
1666 * Inspect sb and determine the true "end" of the log message, in
1667 * order to find where to put a new Signed-off-by: line.  Ignored are
1668 * trailing comment lines and blank lines, and also the traditional
1669 * "Conflicts:" block that is not commented out, so that we can use
1670 * "git commit -s --amend" on an existing commit that forgot to remove
1671 * it.
1672 *
1673 * Returns the number of bytes from the tail to ignore, to be fed as
1674 * the second parameter to append_signoff().
1675 */
1676int ignore_non_trailer(struct strbuf *sb)
1677{
1678        int boc = 0;
1679        int bol = 0;
1680        int in_old_conflicts_block = 0;
1681
1682        while (bol < sb->len) {
1683                char *next_line;
1684
1685                if (!(next_line = memchr(sb->buf + bol, '\n', sb->len - bol)))
1686                        next_line = sb->buf + sb->len;
1687                else
1688                        next_line++;
1689
1690                if (sb->buf[bol] == comment_line_char || sb->buf[bol] == '\n') {
1691                        /* is this the first of the run of comments? */
1692                        if (!boc)
1693                                boc = bol;
1694                        /* otherwise, it is just continuing */
1695                } else if (starts_with(sb->buf + bol, "Conflicts:\n")) {
1696                        in_old_conflicts_block = 1;
1697                        if (!boc)
1698                                boc = bol;
1699                } else if (in_old_conflicts_block && sb->buf[bol] == '\t') {
1700                        ; /* a pathname in the conflicts block */
1701                } else if (boc) {
1702                        /* the previous was not trailing comment */
1703                        boc = 0;
1704                        in_old_conflicts_block = 0;
1705                }
1706                bol = next_line - sb->buf;
1707        }
1708        return boc ? sb->len - boc : 0;
1709}