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 != OBJ_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 = OBJ_COMMIT;
  90                 return ret;
  91         }
  92         if (!obj->type)
  93                 obj->type = OBJ_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         commit->object.flags &= ~mark;
 416         parents = commit->parents;
 417         while (parents) {
 418                 struct commit *parent = parents->item;
 419
 420                 /* Have we already cleared this? */
 421                 if (mark & parent->object.flags)
 422                         clear_commit_marks(parent, mark);
 423                 parents = parents->next;
 424         }
 425 }
 426
 427 /*
 428  * Generic support for pretty-printing the header
 429  */
 430 static int get_one_line(const char *msg, unsigned long len)
 431 {
 432         int ret = 0;
 433
 434         while (len--) {
 435                 char c = *msg++;
 436                 if (!c)
 437                         break;
 438                 ret++;
 439                 if (c == '\n')
 440                         break;
 441         }
 442         return ret;
 443 }
 444
 445 static int is_rfc2047_special(char ch)
 446 {
 447         return ((ch & 0x80) || (ch == '=') || (ch == '?') || (ch == '_'));
 448 }
 449
 450 static int add_rfc2047(char *buf, const char *line, int len)
 451 {
 452         char *bp = buf;
 453         int i, needquote;
 454         static const char q_utf8[] = "=?utf-8?q?";
 455
 456         for (i = needquote = 0; !needquote && i < len; i++) {
 457                 unsigned ch = line[i];
 458                 if (ch & 0x80)
 459                         needquote++;
 460                 if ((i + 1 < len) &&
 461                     (ch == '=' && line[i+1] == '?'))
 462                         needquote++;
 463         }
 464         if (!needquote)
 465                 return sprintf(buf, "%.*s", len, line);
 466
 467         memcpy(bp, q_utf8, sizeof(q_utf8)-1);
 468         bp += sizeof(q_utf8)-1;
 469         for (i = 0; i < len; i++) {
 470                 unsigned ch = line[i] & 0xFF;
 471                 if (is_rfc2047_special(ch)) {
 472                         sprintf(bp, "=%02X", ch);
 473                         bp += 3;
 474                 }
 475                 else if (ch == ' ')
 476                         *bp++ = '_';
 477                 else
 478                         *bp++ = ch;
 479         }
 480         memcpy(bp, "?=", 2);
 481         bp += 2;
 482         return bp - buf;
 483 }
 484
 485 static int add_user_info(const char *what, enum cmit_fmt fmt, char *buf, const char *line)
 486 {
 487         char *date;
 488         int namelen;
 489         unsigned long time;
 490         int tz, ret;
 491         const char *filler = "    ";
 492
 493         if (fmt == CMIT_FMT_ONELINE)
 494                 return 0;
 495         date = strchr(line, '>');
 496         if (!date)
 497                 return 0;
 498         namelen = ++date - line;
 499         time = strtoul(date, &date, 10);
 500         tz = strtol(date, NULL, 10);
 501
 502         if (fmt == CMIT_FMT_EMAIL) {
 503                 char *name_tail = strchr(line, '<');
 504                 int display_name_length;
 505                 if (!name_tail)
 506                         return 0;
 507                 while (line < name_tail && isspace(name_tail[-1]))
 508                         name_tail--;
 509                 display_name_length = name_tail - line;
 510                 filler = "";
 511                 strcpy(buf, "From: ");
 512                 ret = strlen(buf);
 513                 ret += add_rfc2047(buf + ret, line, display_name_length);
 514                 memcpy(buf + ret, name_tail, namelen - display_name_length);
 515                 ret += namelen - display_name_length;
 516                 buf[ret++] = '\n';
 517         }
 518         else {
 519                 ret = sprintf(buf, "%s: %.*s%.*s\n", what,
 520                               (fmt == CMIT_FMT_FULLER) ? 4 : 0,
 521                               filler, namelen, line);
 522         }
 523         switch (fmt) {
 524         case CMIT_FMT_MEDIUM:
 525                 ret += sprintf(buf + ret, "Date:   %s\n", show_date(time, tz));
 526                 break;
 527         case CMIT_FMT_EMAIL:
 528                 ret += sprintf(buf + ret, "Date: %s\n",
 529                                show_rfc2822_date(time, tz));
 530                 break;
 531         case CMIT_FMT_FULLER:
 532                 ret += sprintf(buf + ret, "%sDate: %s\n", what, show_date(time, tz));
 533                 break;
 534         default:
 535                 /* notin' */
 536                 break;
 537         }
 538         return ret;
 539 }
 540
 541 static int is_empty_line(const char *line, int *len_p)
 542 {
 543         int len = *len_p;
 544         while (len && isspace(line[len-1]))
 545                 len--;
 546         *len_p = len;
 547         return !len;
 548 }
 549
 550 static int add_merge_info(enum cmit_fmt fmt, char *buf, const struct commit *commit, int abbrev)
 551 {
 552         struct commit_list *parent = commit->parents;
 553         int offset;
 554
 555         if ((fmt == CMIT_FMT_ONELINE) || (fmt == CMIT_FMT_EMAIL) ||
 556             !parent || !parent->next)
 557                 return 0;
 558
 559         offset = sprintf(buf, "Merge:");
 560
 561         while (parent) {
 562                 struct commit *p = parent->item;
 563                 const char *hex = abbrev
 564                         ? find_unique_abbrev(p->object.sha1, abbrev)
 565                         : sha1_to_hex(p->object.sha1);
 566                 const char *dots = (abbrev && strlen(hex) != 40) ? "..." : "";
 567                 parent = parent->next;
 568
 569                 offset += sprintf(buf + offset, " %s%s", hex, dots);
 570         }
 571         buf[offset++] = '\n';
 572         return offset;
 573 }
 574
 575 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)
 576 {
 577         int hdr = 1, body = 0;
 578         unsigned long offset = 0;
 579         int indent = 4;
 580         int parents_shown = 0;
 581         const char *msg = commit->buffer;
 582         int plain_non_ascii = 0;
 583
 584         if (fmt == CMIT_FMT_ONELINE || fmt == CMIT_FMT_EMAIL)
 585                 indent = 0;
 586
 587         /* After-subject is used to pass in Content-Type: multipart
 588          * MIME header; in that case we do not have to do the
 589          * plaintext content type even if the commit message has
 590          * non 7-bit ASCII character.  Otherwise, check if we need
 591          * to say this is not a 7-bit ASCII.
 592          */
 593         if (fmt == CMIT_FMT_EMAIL && !after_subject) {
 594                 int i, ch, in_body;
 595
 596                 for (in_body = i = 0; (ch = msg[i]) && i < len; i++) {
 597                         if (!in_body) {
 598                                 /* author could be non 7-bit ASCII but
 599                                  * the log may so; skip over the
 600                                  * header part first.
 601                                  */
 602                                 if (ch == '\n' &&
 603                                     i + 1 < len && msg[i+1] == '\n')
 604                                         in_body = 1;
 605                         }
 606                         else if (ch & 0x80) {
 607                                 plain_non_ascii = 1;
 608                                 break;
 609                         }
 610                 }
 611         }
 612
 613         for (;;) {
 614                 const char *line = msg;
 615                 int linelen = get_one_line(msg, len);
 616
 617                 if (!linelen)
 618                         break;
 619
 620                 /*
 621                  * We want some slop for indentation and a possible
 622                  * final "...". Thus the "+ 20".
 623                  */
 624                 if (offset + linelen + 20 > space) {
 625                         memcpy(buf + offset, "    ...\n", 8);
 626                         offset += 8;
 627                         break;
 628                 }
 629
 630                 msg += linelen;
 631                 len -= linelen;
 632                 if (hdr) {
 633                         if (linelen == 1) {
 634                                 hdr = 0;
 635                                 if ((fmt != CMIT_FMT_ONELINE) && !subject)
 636                                         buf[offset++] = '\n';
 637                                 continue;
 638                         }
 639                         if (fmt == CMIT_FMT_RAW) {
 640                                 memcpy(buf + offset, line, linelen);
 641                                 offset += linelen;
 642                                 continue;
 643                         }
 644                         if (!memcmp(line, "parent ", 7)) {
 645                                 if (linelen != 48)
 646                                         die("bad parent line in commit");
 647                                 continue;
 648                         }
 649
 650                         if (!parents_shown) {
 651                                 offset += add_merge_info(fmt, buf + offset,
 652                                                          commit, abbrev);
 653                                 parents_shown = 1;
 654                                 continue;
 655                         }
 656                         /*
 657                          * MEDIUM == DEFAULT shows only author with dates.
 658                          * FULL shows both authors but not dates.
 659                          * FULLER shows both authors and dates.
 660                          */
 661                         if (!memcmp(line, "author ", 7))
 662                                 offset += add_user_info("Author", fmt,
 663                                                         buf + offset,
 664                                                         line + 7);
 665                         if (!memcmp(line, "committer ", 10) &&
 666                             (fmt == CMIT_FMT_FULL || fmt == CMIT_FMT_FULLER))
 667                                 offset += add_user_info("Commit", fmt,
 668                                                         buf + offset,
 669                                                         line + 10);
 670                         continue;
 671                 }
 672
 673                 if (!subject)
 674                         body = 1;
 675
 676                 if (is_empty_line(line, &linelen)) {
 677                         if (!body)
 678                                 continue;
 679                         if (subject)
 680                                 continue;
 681                         if (fmt == CMIT_FMT_SHORT)
 682                                 break;
 683                 }
 684
 685                 if (subject) {
 686                         int slen = strlen(subject);
 687                         memcpy(buf + offset, subject, slen);
 688                         offset += slen;
 689                         offset += add_rfc2047(buf + offset, line, linelen);
 690                 }
 691                 else {
 692                         memset(buf + offset, ' ', indent);
 693                         memcpy(buf + offset + indent, line, linelen);
 694                         offset += linelen + indent;
 695                 }
 696                 buf[offset++] = '\n';
 697                 if (fmt == CMIT_FMT_ONELINE)
 698                         break;
 699                 if (subject && plain_non_ascii) {
 700                         static const char header[] =
 701                                 "Content-Type: text/plain; charset=UTF-8\n"
 702                                 "Content-Transfer-Encoding: 8bit\n";
 703                         memcpy(buf + offset, header, sizeof(header)-1);
 704                         offset += sizeof(header)-1;
 705                 }
 706                 if (after_subject) {
 707                         int slen = strlen(after_subject);
 708                         if (slen > space - offset - 1)
 709                                 slen = space - offset - 1;
 710                         memcpy(buf + offset, after_subject, slen);
 711                         offset += slen;
 712                         after_subject = NULL;
 713                 }
 714                 subject = NULL;
 715         }
 716         while (offset && isspace(buf[offset-1]))
 717                 offset--;
 718         /* Make sure there is an EOLN for the non-oneline case */
 719         if (fmt != CMIT_FMT_ONELINE)
 720                 buf[offset++] = '\n';
 721         /*
 722          * make sure there is another EOLN to separate the headers from whatever
 723          * body the caller appends if we haven't already written a body
 724          */
 725         if (fmt == CMIT_FMT_EMAIL && !body)
 726                 buf[offset++] = '\n';
 727         buf[offset] = '\0';
 728         return offset;
 729 }
 730
 731 struct commit *pop_commit(struct commit_list **stack)
 732 {
 733         struct commit_list *top = *stack;
 734         struct commit *item = top ? top->item : NULL;
 735
 736         if (top) {
 737                 *stack = top->next;
 738                 free(top);
 739         }
 740         return item;
 741 }
 742
 743 int count_parents(struct commit * commit)
 744 {
 745         int count = 0;
 746         struct commit_list * parents = commit->parents;
 747         for (count=0;parents; parents=parents->next,count++)
 748           ;
 749         return count;
 750 }
 751
 752 void topo_sort_default_setter(struct commit *c, void *data)
 753 {
 754         c->util = data;
 755 }
 756
 757 void *topo_sort_default_getter(struct commit *c)
 758 {
 759         return c->util;
 760 }
 761
 762 /*
 763  * Performs an in-place topological sort on the list supplied.
 764  */
 765 void sort_in_topological_order(struct commit_list ** list, int lifo)
 766 {
 767         sort_in_topological_order_fn(list, lifo, topo_sort_default_setter,
 768                                      topo_sort_default_getter);
 769 }
 770
 771 void sort_in_topological_order_fn(struct commit_list ** list, int lifo,
 772                                   topo_sort_set_fn_t setter,
 773                                   topo_sort_get_fn_t getter)
 774 {
 775         struct commit_list * next = *list;
 776         struct commit_list * work = NULL, **insert;
 777         struct commit_list ** pptr = list;
 778         struct sort_node * nodes;
 779         struct sort_node * next_nodes;
 780         int count = 0;
 781
 782         /* determine the size of the list */
 783         while (next) {
 784                 next = next->next;
 785                 count++;
 786         }
 787
 788         if (!count)
 789                 return;
 790         /* allocate an array to help sort the list */
 791         nodes = xcalloc(count, sizeof(*nodes));
 792         /* link the list to the array */
 793         next_nodes = nodes;
 794         next=*list;
 795         while (next) {
 796                 next_nodes->list_item = next;
 797                 setter(next->item, next_nodes);
 798                 next_nodes++;
 799                 next = next->next;
 800         }
 801         /* update the indegree */
 802         next=*list;
 803         while (next) {
 804                 struct commit_list * parents = next->item->parents;
 805                 while (parents) {
 806                         struct commit * parent=parents->item;
 807                         struct sort_node * pn = (struct sort_node *) getter(parent);
 808
 809                         if (pn)
 810                                 pn->indegree++;
 811                         parents=parents->next;
 812                 }
 813                 next=next->next;
 814         }
 815         /*
 816          * find the tips
 817          *
 818          * tips are nodes not reachable from any other node in the list
 819          *
 820          * the tips serve as a starting set for the work queue.
 821          */
 822         next=*list;
 823         insert = &work;
 824         while (next) {
 825                 struct sort_node * node = (struct sort_node *) getter(next->item);
 826
 827                 if (node->indegree == 0) {
 828                         insert = &commit_list_insert(next->item, insert)->next;
 829                 }
 830                 next=next->next;
 831         }
 832
 833         /* process the list in topological order */
 834         if (!lifo)
 835                 sort_by_date(&work);
 836         while (work) {
 837                 struct commit * work_item = pop_commit(&work);
 838                 struct sort_node * work_node = (struct sort_node *) getter(work_item);
 839                 struct commit_list * parents = work_item->parents;
 840
 841                 while (parents) {
 842                         struct commit * parent=parents->item;
 843                         struct sort_node * pn = (struct sort_node *) getter(parent);
 844
 845                         if (pn) {
 846                                 /*
 847                                  * parents are only enqueued for emission
 848                                  * when all their children have been emitted thereby
 849                                  * guaranteeing topological order.
 850                                  */
 851                                 pn->indegree--;
 852                                 if (!pn->indegree) {
 853                                         if (!lifo)
 854                                                 insert_by_date(parent, &work);
 855                                         else
 856                                                 commit_list_insert(parent, &work);
 857                                 }
 858                         }
 859                         parents=parents->next;
 860                 }
 861                 /*
 862                  * work_item is a commit all of whose children
 863                  * have already been emitted. we can emit it now.
 864                  */
 865                 *pptr = work_node->list_item;
 866                 pptr = &(*pptr)->next;
 867                 *pptr = NULL;
 868                 setter(work_item, NULL);
 869         }
 870         free(nodes);
 871 }
 872
 873 /* merge-rebase stuff */
 874
 875 /* bits #0..7 in revision.h */
 876 #define PARENT1         (1u<< 8)
 877 #define PARENT2         (1u<< 9)
 878 #define STALE           (1u<<10)
 879 #define RESULT          (1u<<11)
 880
 881 static struct commit *interesting(struct commit_list *list)
 882 {
 883         while (list) {
 884                 struct commit *commit = list->item;
 885                 list = list->next;
 886                 if (commit->object.flags & STALE)
 887                         continue;
 888                 return commit;
 889         }
 890         return NULL;
 891 }
 892
 893 static struct commit_list *merge_bases(struct commit *one, struct commit *two)
 894 {
 895         struct commit_list *list = NULL;
 896         struct commit_list *result = NULL;
 897
 898         if (one == two)
 899                 /* We do not mark this even with RESULT so we do not
 900                  * have to clean it up.
 901                  */
 902                 return commit_list_insert(one, &result);
 903
 904         parse_commit(one);
 905         parse_commit(two);
 906
 907         one->object.flags |= PARENT1;
 908         two->object.flags |= PARENT2;
 909         insert_by_date(one, &list);
 910         insert_by_date(two, &list);
 911
 912         while (interesting(list)) {
 913                 struct commit *commit;
 914                 struct commit_list *parents;
 915                 struct commit_list *n;
 916                 int flags;
 917
 918                 commit = list->item;
 919                 n = list->next;
 920                 free(list);
 921                 list = n;
 922
 923                 flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
 924                 if (flags == (PARENT1 | PARENT2)) {
 925                         if (!(commit->object.flags & RESULT)) {
 926                                 commit->object.flags |= RESULT;
 927                                 insert_by_date(commit, &result);
 928                         }
 929                         /* Mark parents of a found merge stale */
 930                         flags |= STALE;
 931                 }
 932                 parents = commit->parents;
 933                 while (parents) {
 934                         struct commit *p = parents->item;
 935                         parents = parents->next;
 936                         if ((p->object.flags & flags) == flags)
 937                                 continue;
 938                         parse_commit(p);
 939                         p->object.flags |= flags;
 940                         insert_by_date(p, &list);
 941                 }
 942         }
 943
 944         /* Clean up the result to remove stale ones */
 945         list = result; result = NULL;
 946         while (list) {
 947                 struct commit_list *n = list->next;
 948                 if (!(list->item->object.flags & STALE))
 949                         insert_by_date(list->item, &result);
 950                 free(list);
 951                 list = n;
 952         }
 953         return result;
 954 }
 955
 956 struct commit_list *get_merge_bases(struct commit *one,
 957                                     struct commit *two,
 958                                     int cleanup)
 959 {
 960         const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
 961         struct commit_list *list;
 962         struct commit **rslt;
 963         struct commit_list *result;
 964         int cnt, i, j;
 965
 966         result = merge_bases(one, two);
 967         if (one == two)
 968                 return result;
 969         if (!result || !result->next) {
 970                 if (cleanup) {
 971                         clear_commit_marks(one, all_flags);
 972                         clear_commit_marks(two, all_flags);
 973                 }
 974                 return result;
 975         }
 976
 977         /* There are more than one */
 978         cnt = 0;
 979         list = result;
 980         while (list) {
 981                 list = list->next;
 982                 cnt++;
 983         }
 984         rslt = xcalloc(cnt, sizeof(*rslt));
 985         for (list = result, i = 0; list; list = list->next)
 986                 rslt[i++] = list->item;
 987         free_commit_list(result);
 988
 989         clear_commit_marks(one, all_flags);
 990         clear_commit_marks(two, all_flags);
 991         for (i = 0; i < cnt - 1; i++) {
 992                 for (j = i+1; j < cnt; j++) {
 993                         if (!rslt[i] || !rslt[j])
 994                                 continue;
 995                         result = merge_bases(rslt[i], rslt[j]);
 996                         clear_commit_marks(rslt[i], all_flags);
 997                         clear_commit_marks(rslt[j], all_flags);
 998                         for (list = result; list; list = list->next) {
 999                                 if (rslt[i] == list->item)
1000                                         rslt[i] = NULL;
1001                                 if (rslt[j] == list->item)
1002                                         rslt[j] = NULL;
1003                         }
1004                 }
1005         }
1006
1007         /* Surviving ones in rslt[] are the independent results */
1008         result = NULL;
1009         for (i = 0; i < cnt; i++) {
1010                 if (rslt[i])
1011                         insert_by_date(rslt[i], &result);
1012         }
1013         free(rslt);
1014         return result;
1015 }