commit.c

   1 #include "cache.h"
   2 #include "tag.h"
   3 #include "commit.h"
   4
   5 int save_commit_buffer = 1;
   6
   7 struct sort_node
   8 {
   9         /*
  10          * the number of children of the associated commit
  11          * that also occur in the list being sorted.
  12          */
  13         unsigned int indegree;
  14
  15         /*
  16          * reference to original list item that we will re-use
  17          * on output.
  18          */
  19         struct commit_list * list_item;
  20
  21 };
  22
  23 const char *commit_type = "commit";
  24
  25 struct cmt_fmt_map {
  26         const char *n;
  27         size_t cmp_len;
  28         enum cmit_fmt v;
  29 } cmt_fmts[] = {
  30         { "raw",        1,      CMIT_FMT_RAW },
  31         { "medium",     1,      CMIT_FMT_MEDIUM },
  32         { "short",      1,      CMIT_FMT_SHORT },
  33         { "email",      1,      CMIT_FMT_EMAIL },
  34         { "full",       5,      CMIT_FMT_FULL },
  35         { "fuller",     5,      CMIT_FMT_FULLER },
  36         { "oneline",    1,      CMIT_FMT_ONELINE },
  37 };
  38
  39 enum cmit_fmt get_commit_format(const char *arg)
  40 {
  41         int i;
  42
  43         if (!arg || !*arg)
  44                 return CMIT_FMT_DEFAULT;
  45         if (*arg == '=')
  46                 arg++;
  47         for (i = 0; i < ARRAY_SIZE(cmt_fmts); i++) {
  48                 if (!strncmp(arg, cmt_fmts[i].n, cmt_fmts[i].cmp_len))
  49                         return cmt_fmts[i].v;
  50         }
  51
  52         die("invalid --pretty format: %s", arg);
  53 }
  54
  55 static struct commit *check_commit(struct object *obj,
  56                                    const unsigned char *sha1,
  57                                    int quiet)
  58 {
  59         if (obj->type != TYPE_COMMIT) {
  60                 if (!quiet)
  61                         error("Object %s is a %s, not a commit",
  62                               sha1_to_hex(sha1), typename(obj->type));
  63                 return NULL;
  64         }
  65         return (struct commit *) obj;
  66 }
  67
  68 struct commit *lookup_commit_reference_gently(const unsigned char *sha1,
  69                                               int quiet)
  70 {
  71         struct object *obj = deref_tag(parse_object(sha1), NULL, 0);
  72
  73         if (!obj)
  74                 return NULL;
  75         return check_commit(obj, sha1, quiet);
  76 }
  77
  78 struct commit *lookup_commit_reference(const unsigned char *sha1)
  79 {
  80         return lookup_commit_reference_gently(sha1, 0);
  81 }
  82
  83 struct commit *lookup_commit(const unsigned char *sha1)
  84 {
  85         struct object *obj = lookup_object(sha1);
  86         if (!obj) {
  87                 struct commit *ret = alloc_commit_node();
  88                 created_object(sha1, &ret->object);
  89                 ret->object.type = TYPE_COMMIT;
  90                 return ret;
  91         }
  92         if (!obj->type)
  93                 obj->type = TYPE_COMMIT;
  94         return check_commit(obj, sha1, 0);
  95 }
  96
  97 static unsigned long parse_commit_date(const char *buf)
  98 {
  99         unsigned long date;
 100
 101         if (memcmp(buf, "author", 6))
 102                 return 0;
 103         while (*buf++ != '\n')
 104                 /* nada */;
 105         if (memcmp(buf, "committer", 9))
 106                 return 0;
 107         while (*buf++ != '>')
 108                 /* nada */;
 109         date = strtoul(buf, NULL, 10);
 110         if (date == ULONG_MAX)
 111                 date = 0;
 112         return date;
 113 }
 114
 115 static struct commit_graft **commit_graft;
 116 static int commit_graft_alloc, commit_graft_nr;
 117
 118 static int commit_graft_pos(const unsigned char *sha1)
 119 {
 120         int lo, hi;
 121         lo = 0;
 122         hi = commit_graft_nr;
 123         while (lo < hi) {
 124                 int mi = (lo + hi) / 2;
 125                 struct commit_graft *graft = commit_graft[mi];
 126                 int cmp = memcmp(sha1, graft->sha1, 20);
 127                 if (!cmp)
 128                         return mi;
 129                 if (cmp < 0)
 130                         hi = mi;
 131                 else
 132                         lo = mi + 1;
 133         }
 134         return -lo - 1;
 135 }
 136
 137 int register_commit_graft(struct commit_graft *graft, int ignore_dups)
 138 {
 139         int pos = commit_graft_pos(graft->sha1);
 140
 141         if (0 <= pos) {
 142                 if (ignore_dups)
 143                         free(graft);
 144                 else {
 145                         free(commit_graft[pos]);
 146                         commit_graft[pos] = graft;
 147                 }
 148                 return 1;
 149         }
 150         pos = -pos - 1;
 151         if (commit_graft_alloc <= ++commit_graft_nr) {
 152                 commit_graft_alloc = alloc_nr(commit_graft_alloc);
 153                 commit_graft = xrealloc(commit_graft,
 154                                         sizeof(*commit_graft) *
 155                                         commit_graft_alloc);
 156         }
 157         if (pos < commit_graft_nr)
 158                 memmove(commit_graft + pos + 1,
 159                         commit_graft + pos,
 160                         (commit_graft_nr - pos - 1) *
 161                         sizeof(*commit_graft));
 162         commit_graft[pos] = graft;
 163         return 0;
 164 }
 165
 166 void free_commit_grafts(void)
 167 {
 168         int pos = commit_graft_nr;
 169         while (pos >= 0)
 170                 free(commit_graft[pos--]);
 171         commit_graft_nr = 0;
 172 }
 173
 174 struct commit_graft *read_graft_line(char *buf, int len)
 175 {
 176         /* The format is just "Commit Parent1 Parent2 ...\n" */
 177         int i;
 178         struct commit_graft *graft = NULL;
 179
 180         if (buf[len-1] == '\n')
 181                 buf[--len] = 0;
 182         if (buf[0] == '#' || buf[0] == '\0')
 183                 return NULL;
 184         if ((len + 1) % 41) {
 185         bad_graft_data:
 186                 error("bad graft data: %s", buf);
 187                 free(graft);
 188                 return NULL;
 189         }
 190         i = (len + 1) / 41 - 1;
 191         graft = xmalloc(sizeof(*graft) + 20 * i);
 192         graft->nr_parent = i;
 193         if (get_sha1_hex(buf, graft->sha1))
 194                 goto bad_graft_data;
 195         for (i = 40; i < len; i += 41) {
 196                 if (buf[i] != ' ')
 197                         goto bad_graft_data;
 198                 if (get_sha1_hex(buf + i + 1, graft->parent[i/41]))
 199                         goto bad_graft_data;
 200         }
 201         return graft;
 202 }
 203
 204 int read_graft_file(const char *graft_file)
 205 {
 206         FILE *fp = fopen(graft_file, "r");
 207         char buf[1024];
 208         if (!fp)
 209                 return -1;
 210         while (fgets(buf, sizeof(buf), fp)) {
 211                 /* The format is just "Commit Parent1 Parent2 ...\n" */
 212                 int len = strlen(buf);
 213                 struct commit_graft *graft = read_graft_line(buf, len);
 214                 if (!graft)
 215                         continue;
 216                 if (register_commit_graft(graft, 1))
 217                         error("duplicate graft data: %s", buf);
 218         }
 219         fclose(fp);
 220         return 0;
 221 }
 222
 223 static void prepare_commit_graft(void)
 224 {
 225         static int commit_graft_prepared;
 226         static char *last_graft_file;
 227         char *graft_file = get_graft_file();
 228
 229         if (last_graft_file) {
 230                 if (!strcmp(graft_file, last_graft_file))
 231                         return;
 232                 free_commit_grafts();
 233         }
 234         if (last_graft_file)
 235                 free(last_graft_file);
 236         last_graft_file = strdup(graft_file);
 237
 238         read_graft_file(graft_file);
 239         commit_graft_prepared = 1;
 240 }
 241
 242 static struct commit_graft *lookup_commit_graft(const unsigned char *sha1)
 243 {
 244         int pos;
 245         prepare_commit_graft();
 246         pos = commit_graft_pos(sha1);
 247         if (pos < 0)
 248                 return NULL;
 249         return commit_graft[pos];
 250 }
 251
 252 int parse_commit_buffer(struct commit *item, void *buffer, unsigned long size)
 253 {
 254         char *tail = buffer;
 255         char *bufptr = buffer;
 256         unsigned char parent[20];
 257         struct commit_list **pptr;
 258         struct commit_graft *graft;
 259         unsigned n_refs = 0;
 260
 261         if (item->object.parsed)
 262                 return 0;
 263         item->object.parsed = 1;
 264         tail += size;
 265         if (tail <= bufptr + 5 || memcmp(bufptr, "tree ", 5))
 266                 return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
 267         if (tail <= bufptr + 45 || get_sha1_hex(bufptr + 5, parent) < 0)
 268                 return error("bad tree pointer in commit %s",
 269                              sha1_to_hex(item->object.sha1));
 270         item->tree = lookup_tree(parent);
 271         if (item->tree)
 272                 n_refs++;
 273         bufptr += 46; /* "tree " + "hex sha1" + "\n" */
 274         pptr = &item->parents;
 275
 276         graft = lookup_commit_graft(item->object.sha1);
 277         while (bufptr + 48 < tail && !memcmp(bufptr, "parent ", 7)) {
 278                 struct commit *new_parent;
 279
 280                 if (tail <= bufptr + 48 ||
 281                     get_sha1_hex(bufptr + 7, parent) ||
 282                     bufptr[47] != '\n')
 283                         return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
 284                 bufptr += 48;
 285                 if (graft)
 286                         continue;
 287                 new_parent = lookup_commit(parent);
 288                 if (new_parent) {
 289                         pptr = &commit_list_insert(new_parent, pptr)->next;
 290                         n_refs++;
 291                 }
 292         }
 293         if (graft) {
 294                 int i;
 295                 struct commit *new_parent;
 296                 for (i = 0; i < graft->nr_parent; i++) {
 297                         new_parent = lookup_commit(graft->parent[i]);
 298                         if (!new_parent)
 299                                 continue;
 300                         pptr = &commit_list_insert(new_parent, pptr)->next;
 301                         n_refs++;
 302                 }
 303         }
 304         item->date = parse_commit_date(bufptr);
 305
 306         if (track_object_refs) {
 307                 unsigned i = 0;
 308                 struct commit_list *p;
 309                 struct object_refs *refs = alloc_object_refs(n_refs);
 310                 if (item->tree)
 311                         refs->ref[i++] = &item->tree->object;
 312                 for (p = item->parents; p; p = p->next)
 313                         refs->ref[i++] = &p->item->object;
 314                 set_object_refs(&item->object, refs);
 315         }
 316
 317         return 0;
 318 }
 319
 320 int parse_commit(struct commit *item)
 321 {
 322         char type[20];
 323         void *buffer;
 324         unsigned long size;
 325         int ret;
 326
 327         if (item->object.parsed)
 328                 return 0;
 329         buffer = read_sha1_file(item->object.sha1, type, &size);
 330         if (!buffer)
 331                 return error("Could not read %s",
 332                              sha1_to_hex(item->object.sha1));
 333         if (strcmp(type, commit_type)) {
 334                 free(buffer);
 335                 return error("Object %s not a commit",
 336                              sha1_to_hex(item->object.sha1));
 337         }
 338         ret = parse_commit_buffer(item, buffer, size);
 339         if (save_commit_buffer && !ret) {
 340                 item->buffer = buffer;
 341                 return 0;
 342         }
 343         free(buffer);
 344         return ret;
 345 }
 346
 347 struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
 348 {
 349         struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
 350         new_list->item = item;
 351         new_list->next = *list_p;
 352         *list_p = new_list;
 353         return new_list;
 354 }
 355
 356 void free_commit_list(struct commit_list *list)
 357 {
 358         while (list) {
 359                 struct commit_list *temp = list;
 360                 list = temp->next;
 361                 free(temp);
 362         }
 363 }
 364
 365 struct commit_list * insert_by_date(struct commit *item, struct commit_list **list)
 366 {
 367         struct commit_list **pp = list;
 368         struct commit_list *p;
 369         while ((p = *pp) != NULL) {
 370                 if (p->item->date < item->date) {
 371                         break;
 372                 }
 373                 pp = &p->next;
 374         }
 375         return commit_list_insert(item, pp);
 376 }
 377
 378
 379 void sort_by_date(struct commit_list **list)
 380 {
 381         struct commit_list *ret = NULL;
 382         while (*list) {
 383                 insert_by_date((*list)->item, &ret);
 384                 *list = (*list)->next;
 385         }
 386         *list = ret;
 387 }
 388
 389 struct commit *pop_most_recent_commit(struct commit_list **list,
 390                                       unsigned int mark)
 391 {
 392         struct commit *ret = (*list)->item;
 393         struct commit_list *parents = ret->parents;
 394         struct commit_list *old = *list;
 395
 396         *list = (*list)->next;
 397         free(old);
 398
 399         while (parents) {
 400                 struct commit *commit = parents->item;
 401                 parse_commit(commit);
 402                 if (!(commit->object.flags & mark)) {
 403                         commit->object.flags |= mark;
 404                         insert_by_date(commit, list);
 405                 }
 406                 parents = parents->next;
 407         }
 408         return ret;
 409 }
 410
 411 void clear_commit_marks(struct commit *commit, unsigned int mark)
 412 {
 413         struct commit_list *parents;
 414
 415         parents = commit->parents;
 416         commit->object.flags &= ~mark;
 417         while (parents) {
 418                 struct commit *parent = parents->item;
 419                 if (parent && parent->object.parsed &&
 420                     (parent->object.flags & mark))
 421                         clear_commit_marks(parent, mark);
 422                 parents = parents->next;
 423         }
 424 }
 425
 426 /*
 427  * Generic support for pretty-printing the header
 428  */
 429 static int get_one_line(const char *msg, unsigned long len)
 430 {
 431         int ret = 0;
 432
 433         while (len--) {
 434                 char c = *msg++;
 435                 if (!c)
 436                         break;
 437                 ret++;
 438                 if (c == '\n')
 439                         break;
 440         }
 441         return ret;
 442 }
 443
 444 static int is_rfc2047_special(char ch)
 445 {
 446         return ((ch & 0x80) || (ch == '=') || (ch == '?') || (ch == '_'));
 447 }
 448
 449 static int add_rfc2047(char *buf, const char *line, int len)
 450 {
 451         char *bp = buf;
 452         int i, needquote;
 453         static const char q_utf8[] = "=?utf-8?q?";
 454
 455         for (i = needquote = 0; !needquote && i < len; i++) {
 456                 unsigned ch = line[i];
 457                 if (ch & 0x80)
 458                         needquote++;
 459                 if ((i + 1 < len) &&
 460                     (ch == '=' && line[i+1] == '?'))
 461                         needquote++;
 462         }
 463         if (!needquote)
 464                 return sprintf(buf, "%.*s", len, line);
 465
 466         memcpy(bp, q_utf8, sizeof(q_utf8)-1);
 467         bp += sizeof(q_utf8)-1;
 468         for (i = 0; i < len; i++) {
 469                 unsigned ch = line[i] & 0xFF;
 470                 if (is_rfc2047_special(ch)) {
 471                         sprintf(bp, "=%02X", ch);
 472                         bp += 3;
 473                 }
 474                 else if (ch == ' ')
 475                         *bp++ = '_';
 476                 else
 477                         *bp++ = ch;
 478         }
 479         memcpy(bp, "?=", 2);
 480         bp += 2;
 481         return bp - buf;
 482 }
 483
 484 static int add_user_info(const char *what, enum cmit_fmt fmt, char *buf, const char *line)
 485 {
 486         char *date;
 487         int namelen;
 488         unsigned long time;
 489         int tz, ret;
 490         const char *filler = "    ";
 491
 492         if (fmt == CMIT_FMT_ONELINE)
 493                 return 0;
 494         date = strchr(line, '>');
 495         if (!date)
 496                 return 0;
 497         namelen = ++date - line;
 498         time = strtoul(date, &date, 10);
 499         tz = strtol(date, NULL, 10);
 500
 501         if (fmt == CMIT_FMT_EMAIL) {
 502                 char *name_tail = strchr(line, '<');
 503                 int display_name_length;
 504                 if (!name_tail)
 505                         return 0;
 506                 while (line < name_tail && isspace(name_tail[-1]))
 507                         name_tail--;
 508                 display_name_length = name_tail - line;
 509                 filler = "";
 510                 strcpy(buf, "From: ");
 511                 ret = strlen(buf);
 512                 ret += add_rfc2047(buf + ret, line, display_name_length);
 513                 memcpy(buf + ret, name_tail, namelen - display_name_length);
 514                 ret += namelen - display_name_length;
 515                 buf[ret++] = '\n';
 516         }
 517         else {
 518                 ret = sprintf(buf, "%s: %.*s%.*s\n", what,
 519                               (fmt == CMIT_FMT_FULLER) ? 4 : 0,
 520                               filler, namelen, line);
 521         }
 522         switch (fmt) {
 523         case CMIT_FMT_MEDIUM:
 524                 ret += sprintf(buf + ret, "Date:   %s\n", show_date(time, tz));
 525                 break;
 526         case CMIT_FMT_EMAIL:
 527                 ret += sprintf(buf + ret, "Date: %s\n",
 528                                show_rfc2822_date(time, tz));
 529                 break;
 530         case CMIT_FMT_FULLER:
 531                 ret += sprintf(buf + ret, "%sDate: %s\n", what, show_date(time, tz));
 532                 break;
 533         default:
 534                 /* notin' */
 535                 break;
 536         }
 537         return ret;
 538 }
 539
 540 static int is_empty_line(const char *line, int *len_p)
 541 {
 542         int len = *len_p;
 543         while (len && isspace(line[len-1]))
 544                 len--;
 545         *len_p = len;
 546         return !len;
 547 }
 548
 549 static int add_merge_info(enum cmit_fmt fmt, char *buf, const struct commit *commit, int abbrev)
 550 {
 551         struct commit_list *parent = commit->parents;
 552         int offset;
 553
 554         if ((fmt == CMIT_FMT_ONELINE) || (fmt == CMIT_FMT_EMAIL) ||
 555             !parent || !parent->next)
 556                 return 0;
 557
 558         offset = sprintf(buf, "Merge:");
 559
 560         while (parent) {
 561                 struct commit *p = parent->item;
 562                 const char *hex = abbrev
 563                         ? find_unique_abbrev(p->object.sha1, abbrev)
 564                         : sha1_to_hex(p->object.sha1);
 565                 const char *dots = (abbrev && strlen(hex) != 40) ? "..." : "";
 566                 parent = parent->next;
 567
 568                 offset += sprintf(buf + offset, " %s%s", hex, dots);
 569         }
 570         buf[offset++] = '\n';
 571         return offset;
 572 }
 573
 574 unsigned long pretty_print_commit(enum cmit_fmt fmt, const struct commit *commit, unsigned long len, char *buf, unsigned long space, int abbrev, const char *subject, const char *after_subject)
 575 {
 576         int hdr = 1, body = 0;
 577         unsigned long offset = 0;
 578         int indent = 4;
 579         int parents_shown = 0;
 580         const char *msg = commit->buffer;
 581         int plain_non_ascii = 0;
 582
 583         if (fmt == CMIT_FMT_ONELINE || fmt == CMIT_FMT_EMAIL)
 584                 indent = 0;
 585
 586         /* After-subject is used to pass in Content-Type: multipart
 587          * MIME header; in that case we do not have to do the
 588          * plaintext content type even if the commit message has
 589          * non 7-bit ASCII character.  Otherwise, check if we need
 590          * to say this is not a 7-bit ASCII.
 591          */
 592         if (fmt == CMIT_FMT_EMAIL && !after_subject) {
 593                 int i, ch, in_body;
 594
 595                 for (in_body = i = 0; (ch = msg[i]) && i < len; i++) {
 596                         if (!in_body) {
 597                                 /* author could be non 7-bit ASCII but
 598                                  * the log may so; skip over the
 599                                  * header part first.
 600                                  */
 601                                 if (ch == '\n' &&
 602                                     i + 1 < len && msg[i+1] == '\n')
 603                                         in_body = 1;
 604                         }
 605                         else if (ch & 0x80) {
 606                                 plain_non_ascii = 1;
 607                                 break;
 608                         }
 609                 }
 610         }
 611
 612         for (;;) {
 613                 const char *line = msg;
 614                 int linelen = get_one_line(msg, len);
 615
 616                 if (!linelen)
 617                         break;
 618
 619                 /*
 620                  * We want some slop for indentation and a possible
 621                  * final "...". Thus the "+ 20".
 622                  */
 623                 if (offset + linelen + 20 > space) {
 624                         memcpy(buf + offset, "    ...\n", 8);
 625                         offset += 8;
 626                         break;
 627                 }
 628
 629                 msg += linelen;
 630                 len -= linelen;
 631                 if (hdr) {
 632                         if (linelen == 1) {
 633                                 hdr = 0;
 634                                 if ((fmt != CMIT_FMT_ONELINE) && !subject)
 635                                         buf[offset++] = '\n';
 636                                 continue;
 637                         }
 638                         if (fmt == CMIT_FMT_RAW) {
 639                                 memcpy(buf + offset, line, linelen);
 640                                 offset += linelen;
 641                                 continue;
 642                         }
 643                         if (!memcmp(line, "parent ", 7)) {
 644                                 if (linelen != 48)
 645                                         die("bad parent line in commit");
 646                                 continue;
 647                         }
 648
 649                         if (!parents_shown) {
 650                                 offset += add_merge_info(fmt, buf + offset,
 651                                                          commit, abbrev);
 652                                 parents_shown = 1;
 653                                 continue;
 654                         }
 655                         /*
 656                          * MEDIUM == DEFAULT shows only author with dates.
 657                          * FULL shows both authors but not dates.
 658                          * FULLER shows both authors and dates.
 659                          */
 660                         if (!memcmp(line, "author ", 7))
 661                                 offset += add_user_info("Author", fmt,
 662                                                         buf + offset,
 663                                                         line + 7);
 664                         if (!memcmp(line, "committer ", 10) &&
 665                             (fmt == CMIT_FMT_FULL || fmt == CMIT_FMT_FULLER))
 666                                 offset += add_user_info("Commit", fmt,
 667                                                         buf + offset,
 668                                                         line + 10);
 669                         continue;
 670                 }
 671
 672                 if (is_empty_line(line, &linelen)) {
 673                         if (!body)
 674                                 continue;
 675                         if (subject)
 676                                 continue;
 677                         if (fmt == CMIT_FMT_SHORT)
 678                                 break;
 679                 } else {
 680                         body = 1;
 681                 }
 682
 683                 if (subject) {
 684                         int slen = strlen(subject);
 685                         memcpy(buf + offset, subject, slen);
 686                         offset += slen;
 687                         offset += add_rfc2047(buf + offset, line, linelen);
 688                 }
 689                 else {
 690                         memset(buf + offset, ' ', indent);
 691                         memcpy(buf + offset + indent, line, linelen);
 692                         offset += linelen + indent;
 693                 }
 694                 buf[offset++] = '\n';
 695                 if (fmt == CMIT_FMT_ONELINE)
 696                         break;
 697                 if (subject && plain_non_ascii) {
 698                         static const char header[] =
 699                                 "Content-Type: text/plain; charset=UTF-8\n"
 700                                 "Content-Transfer-Encoding: 8bit\n";
 701                         memcpy(buf + offset, header, sizeof(header)-1);
 702                         offset += sizeof(header)-1;
 703                 }
 704                 if (after_subject) {
 705                         int slen = strlen(after_subject);
 706                         if (slen > space - offset - 1)
 707                                 slen = space - offset - 1;
 708                         memcpy(buf + offset, after_subject, slen);
 709                         offset += slen;
 710                         after_subject = NULL;
 711                 }
 712                 subject = NULL;
 713         }
 714         while (offset && isspace(buf[offset-1]))
 715                 offset--;
 716         /* Make sure there is an EOLN for the non-oneline case */
 717         if (fmt != CMIT_FMT_ONELINE)
 718                 buf[offset++] = '\n';
 719         buf[offset] = '\0';
 720         return offset;
 721 }
 722
 723 struct commit *pop_commit(struct commit_list **stack)
 724 {
 725         struct commit_list *top = *stack;
 726         struct commit *item = top ? top->item : NULL;
 727
 728         if (top) {
 729                 *stack = top->next;
 730                 free(top);
 731         }
 732         return item;
 733 }
 734
 735 int count_parents(struct commit * commit)
 736 {
 737         int count = 0;
 738         struct commit_list * parents = commit->parents;
 739         for (count=0;parents; parents=parents->next,count++)
 740           ;
 741         return count;
 742 }
 743
 744 void topo_sort_default_setter(struct commit *c, void *data)
 745 {
 746         c->util = data;
 747 }
 748
 749 void *topo_sort_default_getter(struct commit *c)
 750 {
 751         return c->util;
 752 }
 753
 754 /*
 755  * Performs an in-place topological sort on the list supplied.
 756  */
 757 void sort_in_topological_order(struct commit_list ** list, int lifo)
 758 {
 759         sort_in_topological_order_fn(list, lifo, topo_sort_default_setter,
 760                                      topo_sort_default_getter);
 761 }
 762
 763 void sort_in_topological_order_fn(struct commit_list ** list, int lifo,
 764                                   topo_sort_set_fn_t setter,
 765                                   topo_sort_get_fn_t getter)
 766 {
 767         struct commit_list * next = *list;
 768         struct commit_list * work = NULL, **insert;
 769         struct commit_list ** pptr = list;
 770         struct sort_node * nodes;
 771         struct sort_node * next_nodes;
 772         int count = 0;
 773
 774         /* determine the size of the list */
 775         while (next) {
 776                 next = next->next;
 777                 count++;
 778         }
 779
 780         if (!count)
 781                 return;
 782         /* allocate an array to help sort the list */
 783         nodes = xcalloc(count, sizeof(*nodes));
 784         /* link the list to the array */
 785         next_nodes = nodes;
 786         next=*list;
 787         while (next) {
 788                 next_nodes->list_item = next;
 789                 setter(next->item, next_nodes);
 790                 next_nodes++;
 791                 next = next->next;
 792         }
 793         /* update the indegree */
 794         next=*list;
 795         while (next) {
 796                 struct commit_list * parents = next->item->parents;
 797                 while (parents) {
 798                         struct commit * parent=parents->item;
 799                         struct sort_node * pn = (struct sort_node *) getter(parent);
 800
 801                         if (pn)
 802                                 pn->indegree++;
 803                         parents=parents->next;
 804                 }
 805                 next=next->next;
 806         }
 807         /*
 808          * find the tips
 809          *
 810          * tips are nodes not reachable from any other node in the list
 811          *
 812          * the tips serve as a starting set for the work queue.
 813          */
 814         next=*list;
 815         insert = &work;
 816         while (next) {
 817                 struct sort_node * node = (struct sort_node *) getter(next->item);
 818
 819                 if (node->indegree == 0) {
 820                         insert = &commit_list_insert(next->item, insert)->next;
 821                 }
 822                 next=next->next;
 823         }
 824
 825         /* process the list in topological order */
 826         if (!lifo)
 827                 sort_by_date(&work);
 828         while (work) {
 829                 struct commit * work_item = pop_commit(&work);
 830                 struct sort_node * work_node = (struct sort_node *) getter(work_item);
 831                 struct commit_list * parents = work_item->parents;
 832
 833                 while (parents) {
 834                         struct commit * parent=parents->item;
 835                         struct sort_node * pn = (struct sort_node *) getter(parent);
 836
 837                         if (pn) {
 838                                 /*
 839                                  * parents are only enqueued for emission
 840                                  * when all their children have been emitted thereby
 841                                  * guaranteeing topological order.
 842                                  */
 843                                 pn->indegree--;
 844                                 if (!pn->indegree) {
 845                                         if (!lifo)
 846                                                 insert_by_date(parent, &work);
 847                                         else
 848                                                 commit_list_insert(parent, &work);
 849                                 }
 850                         }
 851                         parents=parents->next;
 852                 }
 853                 /*
 854                  * work_item is a commit all of whose children
 855                  * have already been emitted. we can emit it now.
 856                  */
 857                 *pptr = work_node->list_item;
 858                 pptr = &(*pptr)->next;
 859                 *pptr = NULL;
 860                 setter(work_item, NULL);
 861         }
 862         free(nodes);
 863 }