commit.c

   1 #include "cache.h"
   2 #include "tag.h"
   3 #include "commit.h"
   4 #include "utf8.h"
   5
   6 int save_commit_buffer = 1;
   7
   8 struct sort_node
   9 {
  10         /*
  11          * the number of children of the associated commit
  12          * that also occur in the list being sorted.
  13          */
  14         unsigned int indegree;
  15
  16         /*
  17          * reference to original list item that we will re-use
  18          * on output.
  19          */
  20         struct commit_list * list_item;
  21
  22 };
  23
  24 const char *commit_type = "commit";
  25
  26 struct cmt_fmt_map {
  27         const char *n;
  28         size_t cmp_len;
  29         enum cmit_fmt v;
  30 } cmt_fmts[] = {
  31         { "raw",        1,      CMIT_FMT_RAW },
  32         { "medium",     1,      CMIT_FMT_MEDIUM },
  33         { "short",      1,      CMIT_FMT_SHORT },
  34         { "email",      1,      CMIT_FMT_EMAIL },
  35         { "full",       5,      CMIT_FMT_FULL },
  36         { "fuller",     5,      CMIT_FMT_FULLER },
  37         { "oneline",    1,      CMIT_FMT_ONELINE },
  38 };
  39
  40 enum cmit_fmt get_commit_format(const char *arg)
  41 {
  42         int i;
  43
  44         if (!arg || !*arg)
  45                 return CMIT_FMT_DEFAULT;
  46         if (*arg == '=')
  47                 arg++;
  48         for (i = 0; i < ARRAY_SIZE(cmt_fmts); i++) {
  49                 if (!strncmp(arg, cmt_fmts[i].n, cmt_fmts[i].cmp_len))
  50                         return cmt_fmts[i].v;
  51         }
  52
  53         die("invalid --pretty format: %s", arg);
  54 }
  55
  56 static struct commit *check_commit(struct object *obj,
  57                                    const unsigned char *sha1,
  58                                    int quiet)
  59 {
  60         if (obj->type != OBJ_COMMIT) {
  61                 if (!quiet)
  62                         error("Object %s is a %s, not a commit",
  63                               sha1_to_hex(sha1), typename(obj->type));
  64                 return NULL;
  65         }
  66         return (struct commit *) obj;
  67 }
  68
  69 struct commit *lookup_commit_reference_gently(const unsigned char *sha1,
  70                                               int quiet)
  71 {
  72         struct object *obj = deref_tag(parse_object(sha1), NULL, 0);
  73
  74         if (!obj)
  75                 return NULL;
  76         return check_commit(obj, sha1, quiet);
  77 }
  78
  79 struct commit *lookup_commit_reference(const unsigned char *sha1)
  80 {
  81         return lookup_commit_reference_gently(sha1, 0);
  82 }
  83
  84 struct commit *lookup_commit(const unsigned char *sha1)
  85 {
  86         struct object *obj = lookup_object(sha1);
  87         if (!obj) {
  88                 struct commit *ret = alloc_commit_node();
  89                 created_object(sha1, &ret->object);
  90                 ret->object.type = OBJ_COMMIT;
  91                 return ret;
  92         }
  93         if (!obj->type)
  94                 obj->type = OBJ_COMMIT;
  95         return check_commit(obj, sha1, 0);
  96 }
  97
  98 static unsigned long parse_commit_date(const char *buf)
  99 {
 100         unsigned long date;
 101
 102         if (memcmp(buf, "author", 6))
 103                 return 0;
 104         while (*buf++ != '\n')
 105                 /* nada */;
 106         if (memcmp(buf, "committer", 9))
 107                 return 0;
 108         while (*buf++ != '>')
 109                 /* nada */;
 110         date = strtoul(buf, NULL, 10);
 111         if (date == ULONG_MAX)
 112                 date = 0;
 113         return date;
 114 }
 115
 116 static struct commit_graft **commit_graft;
 117 static int commit_graft_alloc, commit_graft_nr;
 118
 119 static int commit_graft_pos(const unsigned char *sha1)
 120 {
 121         int lo, hi;
 122         lo = 0;
 123         hi = commit_graft_nr;
 124         while (lo < hi) {
 125                 int mi = (lo + hi) / 2;
 126                 struct commit_graft *graft = commit_graft[mi];
 127                 int cmp = hashcmp(sha1, graft->sha1);
 128                 if (!cmp)
 129                         return mi;
 130                 if (cmp < 0)
 131                         hi = mi;
 132                 else
 133                         lo = mi + 1;
 134         }
 135         return -lo - 1;
 136 }
 137
 138 int register_commit_graft(struct commit_graft *graft, int ignore_dups)
 139 {
 140         int pos = commit_graft_pos(graft->sha1);
 141
 142         if (0 <= pos) {
 143                 if (ignore_dups)
 144                         free(graft);
 145                 else {
 146                         free(commit_graft[pos]);
 147                         commit_graft[pos] = graft;
 148                 }
 149                 return 1;
 150         }
 151         pos = -pos - 1;
 152         if (commit_graft_alloc <= ++commit_graft_nr) {
 153                 commit_graft_alloc = alloc_nr(commit_graft_alloc);
 154                 commit_graft = xrealloc(commit_graft,
 155                                         sizeof(*commit_graft) *
 156                                         commit_graft_alloc);
 157         }
 158         if (pos < commit_graft_nr)
 159                 memmove(commit_graft + pos + 1,
 160                         commit_graft + pos,
 161                         (commit_graft_nr - pos - 1) *
 162                         sizeof(*commit_graft));
 163         commit_graft[pos] = graft;
 164         return 0;
 165 }
 166
 167 struct commit_graft *read_graft_line(char *buf, int len)
 168 {
 169         /* The format is just "Commit Parent1 Parent2 ...\n" */
 170         int i;
 171         struct commit_graft *graft = NULL;
 172
 173         if (buf[len-1] == '\n')
 174                 buf[--len] = 0;
 175         if (buf[0] == '#' || buf[0] == '\0')
 176                 return NULL;
 177         if ((len + 1) % 41) {
 178         bad_graft_data:
 179                 error("bad graft data: %s", buf);
 180                 free(graft);
 181                 return NULL;
 182         }
 183         i = (len + 1) / 41 - 1;
 184         graft = xmalloc(sizeof(*graft) + 20 * i);
 185         graft->nr_parent = i;
 186         if (get_sha1_hex(buf, graft->sha1))
 187                 goto bad_graft_data;
 188         for (i = 40; i < len; i += 41) {
 189                 if (buf[i] != ' ')
 190                         goto bad_graft_data;
 191                 if (get_sha1_hex(buf + i + 1, graft->parent[i/41]))
 192                         goto bad_graft_data;
 193         }
 194         return graft;
 195 }
 196
 197 int read_graft_file(const char *graft_file)
 198 {
 199         FILE *fp = fopen(graft_file, "r");
 200         char buf[1024];
 201         if (!fp)
 202                 return -1;
 203         while (fgets(buf, sizeof(buf), fp)) {
 204                 /* The format is just "Commit Parent1 Parent2 ...\n" */
 205                 int len = strlen(buf);
 206                 struct commit_graft *graft = read_graft_line(buf, len);
 207                 if (!graft)
 208                         continue;
 209                 if (register_commit_graft(graft, 1))
 210                         error("duplicate graft data: %s", buf);
 211         }
 212         fclose(fp);
 213         return 0;
 214 }
 215
 216 static void prepare_commit_graft(void)
 217 {
 218         static int commit_graft_prepared;
 219         char *graft_file;
 220
 221         if (commit_graft_prepared)
 222                 return;
 223         graft_file = get_graft_file();
 224         read_graft_file(graft_file);
 225         commit_graft_prepared = 1;
 226 }
 227
 228 static struct commit_graft *lookup_commit_graft(const unsigned char *sha1)
 229 {
 230         int pos;
 231         prepare_commit_graft();
 232         pos = commit_graft_pos(sha1);
 233         if (pos < 0)
 234                 return NULL;
 235         return commit_graft[pos];
 236 }
 237
 238 int parse_commit_buffer(struct commit *item, void *buffer, unsigned long size)
 239 {
 240         char *tail = buffer;
 241         char *bufptr = buffer;
 242         unsigned char parent[20];
 243         struct commit_list **pptr;
 244         struct commit_graft *graft;
 245         unsigned n_refs = 0;
 246
 247         if (item->object.parsed)
 248                 return 0;
 249         item->object.parsed = 1;
 250         tail += size;
 251         if (tail <= bufptr + 5 || memcmp(bufptr, "tree ", 5))
 252                 return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
 253         if (tail <= bufptr + 45 || get_sha1_hex(bufptr + 5, parent) < 0)
 254                 return error("bad tree pointer in commit %s",
 255                              sha1_to_hex(item->object.sha1));
 256         item->tree = lookup_tree(parent);
 257         if (item->tree)
 258                 n_refs++;
 259         bufptr += 46; /* "tree " + "hex sha1" + "\n" */
 260         pptr = &item->parents;
 261
 262         graft = lookup_commit_graft(item->object.sha1);
 263         while (bufptr + 48 < tail && !memcmp(bufptr, "parent ", 7)) {
 264                 struct commit *new_parent;
 265
 266                 if (tail <= bufptr + 48 ||
 267                     get_sha1_hex(bufptr + 7, parent) ||
 268                     bufptr[47] != '\n')
 269                         return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
 270                 bufptr += 48;
 271                 if (graft)
 272                         continue;
 273                 new_parent = lookup_commit(parent);
 274                 if (new_parent) {
 275                         pptr = &commit_list_insert(new_parent, pptr)->next;
 276                         n_refs++;
 277                 }
 278         }
 279         if (graft) {
 280                 int i;
 281                 struct commit *new_parent;
 282                 for (i = 0; i < graft->nr_parent; i++) {
 283                         new_parent = lookup_commit(graft->parent[i]);
 284                         if (!new_parent)
 285                                 continue;
 286                         pptr = &commit_list_insert(new_parent, pptr)->next;
 287                         n_refs++;
 288                 }
 289         }
 290         item->date = parse_commit_date(bufptr);
 291
 292         if (track_object_refs) {
 293                 unsigned i = 0;
 294                 struct commit_list *p;
 295                 struct object_refs *refs = alloc_object_refs(n_refs);
 296                 if (item->tree)
 297                         refs->ref[i++] = &item->tree->object;
 298                 for (p = item->parents; p; p = p->next)
 299                         refs->ref[i++] = &p->item->object;
 300                 set_object_refs(&item->object, refs);
 301         }
 302
 303         return 0;
 304 }
 305
 306 int parse_commit(struct commit *item)
 307 {
 308         char type[20];
 309         void *buffer;
 310         unsigned long size;
 311         int ret;
 312
 313         if (item->object.parsed)
 314                 return 0;
 315         buffer = read_sha1_file(item->object.sha1, type, &size);
 316         if (!buffer)
 317                 return error("Could not read %s",
 318                              sha1_to_hex(item->object.sha1));
 319         if (strcmp(type, commit_type)) {
 320                 free(buffer);
 321                 return error("Object %s not a commit",
 322                              sha1_to_hex(item->object.sha1));
 323         }
 324         ret = parse_commit_buffer(item, buffer, size);
 325         if (save_commit_buffer && !ret) {
 326                 item->buffer = buffer;
 327                 return 0;
 328         }
 329         free(buffer);
 330         return ret;
 331 }
 332
 333 struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
 334 {
 335         struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
 336         new_list->item = item;
 337         new_list->next = *list_p;
 338         *list_p = new_list;
 339         return new_list;
 340 }
 341
 342 void free_commit_list(struct commit_list *list)
 343 {
 344         while (list) {
 345                 struct commit_list *temp = list;
 346                 list = temp->next;
 347                 free(temp);
 348         }
 349 }
 350
 351 struct commit_list * insert_by_date(struct commit *item, struct commit_list **list)
 352 {
 353         struct commit_list **pp = list;
 354         struct commit_list *p;
 355         while ((p = *pp) != NULL) {
 356                 if (p->item->date < item->date) {
 357                         break;
 358                 }
 359                 pp = &p->next;
 360         }
 361         return commit_list_insert(item, pp);
 362 }
 363
 364
 365 void sort_by_date(struct commit_list **list)
 366 {
 367         struct commit_list *ret = NULL;
 368         while (*list) {
 369                 insert_by_date((*list)->item, &ret);
 370                 *list = (*list)->next;
 371         }
 372         *list = ret;
 373 }
 374
 375 struct commit *pop_most_recent_commit(struct commit_list **list,
 376                                       unsigned int mark)
 377 {
 378         struct commit *ret = (*list)->item;
 379         struct commit_list *parents = ret->parents;
 380         struct commit_list *old = *list;
 381
 382         *list = (*list)->next;
 383         free(old);
 384
 385         while (parents) {
 386                 struct commit *commit = parents->item;
 387                 parse_commit(commit);
 388                 if (!(commit->object.flags & mark)) {
 389                         commit->object.flags |= mark;
 390                         insert_by_date(commit, list);
 391                 }
 392                 parents = parents->next;
 393         }
 394         return ret;
 395 }
 396
 397 void clear_commit_marks(struct commit *commit, unsigned int mark)
 398 {
 399         struct commit_list *parents;
 400
 401         commit->object.flags &= ~mark;
 402         parents = commit->parents;
 403         while (parents) {
 404                 struct commit *parent = parents->item;
 405
 406                 /* Have we already cleared this? */
 407                 if (mark & parent->object.flags)
 408                         clear_commit_marks(parent, mark);
 409                 parents = parents->next;
 410         }
 411 }
 412
 413 /*
 414  * Generic support for pretty-printing the header
 415  */
 416 static int get_one_line(const char *msg, unsigned long len)
 417 {
 418         int ret = 0;
 419
 420         while (len--) {
 421                 char c = *msg++;
 422                 if (!c)
 423                         break;
 424                 ret++;
 425                 if (c == '\n')
 426                         break;
 427         }
 428         return ret;
 429 }
 430
 431 static int is_rfc2047_special(char ch)
 432 {
 433         return ((ch & 0x80) || (ch == '=') || (ch == '?') || (ch == '_'));
 434 }
 435
 436 static int add_rfc2047(char *buf, const char *line, int len)
 437 {
 438         char *bp = buf;
 439         int i, needquote;
 440         static const char q_utf8[] = "=?utf-8?q?";
 441
 442         for (i = needquote = 0; !needquote && i < len; i++) {
 443                 unsigned ch = line[i];
 444                 if (ch & 0x80)
 445                         needquote++;
 446                 if ((i + 1 < len) &&
 447                     (ch == '=' && line[i+1] == '?'))
 448                         needquote++;
 449         }
 450         if (!needquote)
 451                 return sprintf(buf, "%.*s", len, line);
 452
 453         memcpy(bp, q_utf8, sizeof(q_utf8)-1);
 454         bp += sizeof(q_utf8)-1;
 455         for (i = 0; i < len; i++) {
 456                 unsigned ch = line[i] & 0xFF;
 457                 if (is_rfc2047_special(ch)) {
 458                         sprintf(bp, "=%02X", ch);
 459                         bp += 3;
 460                 }
 461                 else if (ch == ' ')
 462                         *bp++ = '_';
 463                 else
 464                         *bp++ = ch;
 465         }
 466         memcpy(bp, "?=", 2);
 467         bp += 2;
 468         return bp - buf;
 469 }
 470
 471 static int add_user_info(const char *what, enum cmit_fmt fmt, char *buf,
 472                          const char *line, int relative_date)
 473 {
 474         char *date;
 475         int namelen;
 476         unsigned long time;
 477         int tz, ret;
 478         const char *filler = "    ";
 479
 480         if (fmt == CMIT_FMT_ONELINE)
 481                 return 0;
 482         date = strchr(line, '>');
 483         if (!date)
 484                 return 0;
 485         namelen = ++date - line;
 486         time = strtoul(date, &date, 10);
 487         tz = strtol(date, NULL, 10);
 488
 489         if (fmt == CMIT_FMT_EMAIL) {
 490                 char *name_tail = strchr(line, '<');
 491                 int display_name_length;
 492                 if (!name_tail)
 493                         return 0;
 494                 while (line < name_tail && isspace(name_tail[-1]))
 495                         name_tail--;
 496                 display_name_length = name_tail - line;
 497                 filler = "";
 498                 strcpy(buf, "From: ");
 499                 ret = strlen(buf);
 500                 ret += add_rfc2047(buf + ret, line, display_name_length);
 501                 memcpy(buf + ret, name_tail, namelen - display_name_length);
 502                 ret += namelen - display_name_length;
 503                 buf[ret++] = '\n';
 504         }
 505         else {
 506                 ret = sprintf(buf, "%s: %.*s%.*s\n", what,
 507                               (fmt == CMIT_FMT_FULLER) ? 4 : 0,
 508                               filler, namelen, line);
 509         }
 510         switch (fmt) {
 511         case CMIT_FMT_MEDIUM:
 512                 ret += sprintf(buf + ret, "Date:   %s\n",
 513                                show_date(time, tz, relative_date));
 514                 break;
 515         case CMIT_FMT_EMAIL:
 516                 ret += sprintf(buf + ret, "Date: %s\n",
 517                                show_rfc2822_date(time, tz));
 518                 break;
 519         case CMIT_FMT_FULLER:
 520                 ret += sprintf(buf + ret, "%sDate: %s\n", what,
 521                                show_date(time, tz, relative_date));
 522                 break;
 523         default:
 524                 /* notin' */
 525                 break;
 526         }
 527         return ret;
 528 }
 529
 530 static int is_empty_line(const char *line, int *len_p)
 531 {
 532         int len = *len_p;
 533         while (len && isspace(line[len-1]))
 534                 len--;
 535         *len_p = len;
 536         return !len;
 537 }
 538
 539 static int add_merge_info(enum cmit_fmt fmt, char *buf, const struct commit *commit, int abbrev)
 540 {
 541         struct commit_list *parent = commit->parents;
 542         int offset;
 543
 544         if ((fmt == CMIT_FMT_ONELINE) || (fmt == CMIT_FMT_EMAIL) ||
 545             !parent || !parent->next)
 546                 return 0;
 547
 548         offset = sprintf(buf, "Merge:");
 549
 550         while (parent) {
 551                 struct commit *p = parent->item;
 552                 const char *hex = NULL;
 553                 const char *dots;
 554                 if (abbrev)
 555                         hex = find_unique_abbrev(p->object.sha1, abbrev);
 556                 if (!hex)
 557                         hex = sha1_to_hex(p->object.sha1);
 558                 dots = (abbrev && strlen(hex) != 40) ?  "..." : "";
 559                 parent = parent->next;
 560
 561                 offset += sprintf(buf + offset, " %s%s", hex, dots);
 562         }
 563         buf[offset++] = '\n';
 564         return offset;
 565 }
 566
 567 static char *get_header(const struct commit *commit, const char *key)
 568 {
 569         int key_len = strlen(key);
 570         const char *line = commit->buffer;
 571
 572         for (;;) {
 573                 const char *eol = strchr(line, '\n'), *next;
 574
 575                 if (line == eol)
 576                         return NULL;
 577                 if (!eol) {
 578                         eol = line + strlen(line);
 579                         next = NULL;
 580                 } else
 581                         next = eol + 1;
 582                 if (!strncmp(line, key, key_len) && line[key_len] == ' ') {
 583                         int len = eol - line - key_len;
 584                         char *ret = xmalloc(len);
 585                         memcpy(ret, line + key_len + 1, len - 1);
 586                         ret[len - 1] = '\0';
 587                         return ret;
 588                 }
 589                 line = next;
 590         }
 591 }
 592
 593 static char *logmsg_reencode(const struct commit *commit)
 594 {
 595         char *encoding;
 596         char *out;
 597         char *output_encoding = (git_log_output_encoding
 598                                  ? git_log_output_encoding
 599                                  : git_commit_encoding);
 600
 601         if (!output_encoding)
 602                 return NULL;
 603         encoding = get_header(commit, "encoding");
 604         if (!encoding || !strcmp(encoding, output_encoding)) {
 605                 free(encoding);
 606                 return NULL;
 607         }
 608         out = reencode_string(commit->buffer, output_encoding, encoding);
 609         free(encoding);
 610         if (!out)
 611                 return NULL;
 612         return out;
 613 }
 614
 615 unsigned long pretty_print_commit(enum cmit_fmt fmt,
 616                                   const struct commit *commit,
 617                                   unsigned long len,
 618                                   char *buf, unsigned long space,
 619                                   int abbrev, const char *subject,
 620                                   const char *after_subject,
 621                                   int relative_date)
 622 {
 623         int hdr = 1, body = 0;
 624         unsigned long offset = 0;
 625         int indent = 4;
 626         int parents_shown = 0;
 627         const char *msg = commit->buffer;
 628         int plain_non_ascii = 0;
 629         char *reencoded = logmsg_reencode(commit);
 630
 631         if (reencoded)
 632                 msg = reencoded;
 633
 634         if (fmt == CMIT_FMT_ONELINE || fmt == CMIT_FMT_EMAIL)
 635                 indent = 0;
 636
 637         /* After-subject is used to pass in Content-Type: multipart
 638          * MIME header; in that case we do not have to do the
 639          * plaintext content type even if the commit message has
 640          * non 7-bit ASCII character.  Otherwise, check if we need
 641          * to say this is not a 7-bit ASCII.
 642          */
 643         if (fmt == CMIT_FMT_EMAIL && !after_subject) {
 644                 int i, ch, in_body;
 645
 646                 for (in_body = i = 0; (ch = msg[i]) && i < len; i++) {
 647                         if (!in_body) {
 648                                 /* author could be non 7-bit ASCII but
 649                                  * the log may be so; skip over the
 650                                  * header part first.
 651                                  */
 652                                 if (ch == '\n' &&
 653                                     i + 1 < len && msg[i+1] == '\n')
 654                                         in_body = 1;
 655                         }
 656                         else if (ch & 0x80) {
 657                                 plain_non_ascii = 1;
 658                                 break;
 659                         }
 660                 }
 661         }
 662
 663         for (;;) {
 664                 const char *line = msg;
 665                 int linelen = get_one_line(msg, len);
 666
 667                 if (!linelen)
 668                         break;
 669
 670                 /*
 671                  * We want some slop for indentation and a possible
 672                  * final "...". Thus the "+ 20".
 673                  */
 674                 if (offset + linelen + 20 > space) {
 675                         memcpy(buf + offset, "    ...\n", 8);
 676                         offset += 8;
 677                         break;
 678                 }
 679
 680                 msg += linelen;
 681                 len -= linelen;
 682                 if (hdr) {
 683                         if (linelen == 1) {
 684                                 hdr = 0;
 685                                 if ((fmt != CMIT_FMT_ONELINE) && !subject)
 686                                         buf[offset++] = '\n';
 687                                 continue;
 688                         }
 689                         if (fmt == CMIT_FMT_RAW) {
 690                                 memcpy(buf + offset, line, linelen);
 691                                 offset += linelen;
 692                                 continue;
 693                         }
 694                         if (!memcmp(line, "parent ", 7)) {
 695                                 if (linelen != 48)
 696                                         die("bad parent line in commit");
 697                                 continue;
 698                         }
 699
 700                         if (!parents_shown) {
 701                                 offset += add_merge_info(fmt, buf + offset,
 702                                                          commit, abbrev);
 703                                 parents_shown = 1;
 704                                 continue;
 705                         }
 706                         /*
 707                          * MEDIUM == DEFAULT shows only author with dates.
 708                          * FULL shows both authors but not dates.
 709                          * FULLER shows both authors and dates.
 710                          */
 711                         if (!memcmp(line, "author ", 7))
 712                                 offset += add_user_info("Author", fmt,
 713                                                         buf + offset,
 714                                                         line + 7,
 715                                                         relative_date);
 716                         if (!memcmp(line, "committer ", 10) &&
 717                             (fmt == CMIT_FMT_FULL || fmt == CMIT_FMT_FULLER))
 718                                 offset += add_user_info("Commit", fmt,
 719                                                         buf + offset,
 720                                                         line + 10,
 721                                                         relative_date);
 722                         continue;
 723                 }
 724
 725                 if (!subject)
 726                         body = 1;
 727
 728                 if (is_empty_line(line, &linelen)) {
 729                         if (!body)
 730                                 continue;
 731                         if (subject)
 732                                 continue;
 733                         if (fmt == CMIT_FMT_SHORT)
 734                                 break;
 735                 }
 736
 737                 if (subject) {
 738                         int slen = strlen(subject);
 739                         memcpy(buf + offset, subject, slen);
 740                         offset += slen;
 741                         offset += add_rfc2047(buf + offset, line, linelen);
 742                 }
 743                 else {
 744                         memset(buf + offset, ' ', indent);
 745                         memcpy(buf + offset + indent, line, linelen);
 746                         offset += linelen + indent;
 747                 }
 748                 buf[offset++] = '\n';
 749                 if (fmt == CMIT_FMT_ONELINE)
 750                         break;
 751                 if (subject && plain_non_ascii) {
 752                         static const char header[] =
 753                                 "Content-Type: text/plain; charset=UTF-8\n"
 754                                 "Content-Transfer-Encoding: 8bit\n";
 755                         memcpy(buf + offset, header, sizeof(header)-1);
 756                         offset += sizeof(header)-1;
 757                 }
 758                 if (after_subject) {
 759                         int slen = strlen(after_subject);
 760                         if (slen > space - offset - 1)
 761                                 slen = space - offset - 1;
 762                         memcpy(buf + offset, after_subject, slen);
 763                         offset += slen;
 764                         after_subject = NULL;
 765                 }
 766                 subject = NULL;
 767         }
 768         while (offset && isspace(buf[offset-1]))
 769                 offset--;
 770         /* Make sure there is an EOLN for the non-oneline case */
 771         if (fmt != CMIT_FMT_ONELINE)
 772                 buf[offset++] = '\n';
 773         /*
 774          * make sure there is another EOLN to separate the headers from whatever
 775          * body the caller appends if we haven't already written a body
 776          */
 777         if (fmt == CMIT_FMT_EMAIL && !body)
 778                 buf[offset++] = '\n';
 779         buf[offset] = '\0';
 780
 781         free(reencoded);
 782         return offset;
 783 }
 784
 785 struct commit *pop_commit(struct commit_list **stack)
 786 {
 787         struct commit_list *top = *stack;
 788         struct commit *item = top ? top->item : NULL;
 789
 790         if (top) {
 791                 *stack = top->next;
 792                 free(top);
 793         }
 794         return item;
 795 }
 796
 797 int count_parents(struct commit * commit)
 798 {
 799         int count;
 800         struct commit_list * parents = commit->parents;
 801         for (count = 0; parents; parents = parents->next,count++)
 802                 ;
 803         return count;
 804 }
 805
 806 void topo_sort_default_setter(struct commit *c, void *data)
 807 {
 808         c->util = data;
 809 }
 810
 811 void *topo_sort_default_getter(struct commit *c)
 812 {
 813         return c->util;
 814 }
 815
 816 /*
 817  * Performs an in-place topological sort on the list supplied.
 818  */
 819 void sort_in_topological_order(struct commit_list ** list, int lifo)
 820 {
 821         sort_in_topological_order_fn(list, lifo, topo_sort_default_setter,
 822                                      topo_sort_default_getter);
 823 }
 824
 825 void sort_in_topological_order_fn(struct commit_list ** list, int lifo,
 826                                   topo_sort_set_fn_t setter,
 827                                   topo_sort_get_fn_t getter)
 828 {
 829         struct commit_list * next = *list;
 830         struct commit_list * work = NULL, **insert;
 831         struct commit_list ** pptr = list;
 832         struct sort_node * nodes;
 833         struct sort_node * next_nodes;
 834         int count = 0;
 835
 836         /* determine the size of the list */
 837         while (next) {
 838                 next = next->next;
 839                 count++;
 840         }
 841
 842         if (!count)
 843                 return;
 844         /* allocate an array to help sort the list */
 845         nodes = xcalloc(count, sizeof(*nodes));
 846         /* link the list to the array */
 847         next_nodes = nodes;
 848         next=*list;
 849         while (next) {
 850                 next_nodes->list_item = next;
 851                 setter(next->item, next_nodes);
 852                 next_nodes++;
 853                 next = next->next;
 854         }
 855         /* update the indegree */
 856         next=*list;
 857         while (next) {
 858                 struct commit_list * parents = next->item->parents;
 859                 while (parents) {
 860                         struct commit * parent=parents->item;
 861                         struct sort_node * pn = (struct sort_node *) getter(parent);
 862
 863                         if (pn)
 864                                 pn->indegree++;
 865                         parents=parents->next;
 866                 }
 867                 next=next->next;
 868         }
 869         /*
 870          * find the tips
 871          *
 872          * tips are nodes not reachable from any other node in the list
 873          *
 874          * the tips serve as a starting set for the work queue.
 875          */
 876         next=*list;
 877         insert = &work;
 878         while (next) {
 879                 struct sort_node * node = (struct sort_node *) getter(next->item);
 880
 881                 if (node->indegree == 0) {
 882                         insert = &commit_list_insert(next->item, insert)->next;
 883                 }
 884                 next=next->next;
 885         }
 886
 887         /* process the list in topological order */
 888         if (!lifo)
 889                 sort_by_date(&work);
 890         while (work) {
 891                 struct commit * work_item = pop_commit(&work);
 892                 struct sort_node * work_node = (struct sort_node *) getter(work_item);
 893                 struct commit_list * parents = work_item->parents;
 894
 895                 while (parents) {
 896                         struct commit * parent=parents->item;
 897                         struct sort_node * pn = (struct sort_node *) getter(parent);
 898
 899                         if (pn) {
 900                                 /*
 901                                  * parents are only enqueued for emission
 902                                  * when all their children have been emitted thereby
 903                                  * guaranteeing topological order.
 904                                  */
 905                                 pn->indegree--;
 906                                 if (!pn->indegree) {
 907                                         if (!lifo)
 908                                                 insert_by_date(parent, &work);
 909                                         else
 910                                                 commit_list_insert(parent, &work);
 911                                 }
 912                         }
 913                         parents=parents->next;
 914                 }
 915                 /*
 916                  * work_item is a commit all of whose children
 917                  * have already been emitted. we can emit it now.
 918                  */
 919                 *pptr = work_node->list_item;
 920                 pptr = &(*pptr)->next;
 921                 *pptr = NULL;
 922                 setter(work_item, NULL);
 923         }
 924         free(nodes);
 925 }
 926
 927 /* merge-rebase stuff */
 928
 929 /* bits #0..15 in revision.h */
 930 #define PARENT1         (1u<<16)
 931 #define PARENT2         (1u<<17)
 932 #define STALE           (1u<<18)
 933 #define RESULT          (1u<<19)
 934
 935 static struct commit *interesting(struct commit_list *list)
 936 {
 937         while (list) {
 938                 struct commit *commit = list->item;
 939                 list = list->next;
 940                 if (commit->object.flags & STALE)
 941                         continue;
 942                 return commit;
 943         }
 944         return NULL;
 945 }
 946
 947 static struct commit_list *merge_bases(struct commit *one, struct commit *two)
 948 {
 949         struct commit_list *list = NULL;
 950         struct commit_list *result = NULL;
 951
 952         if (one == two)
 953                 /* We do not mark this even with RESULT so we do not
 954                  * have to clean it up.
 955                  */
 956                 return commit_list_insert(one, &result);
 957
 958         parse_commit(one);
 959         parse_commit(two);
 960
 961         one->object.flags |= PARENT1;
 962         two->object.flags |= PARENT2;
 963         insert_by_date(one, &list);
 964         insert_by_date(two, &list);
 965
 966         while (interesting(list)) {
 967                 struct commit *commit;
 968                 struct commit_list *parents;
 969                 struct commit_list *n;
 970                 int flags;
 971
 972                 commit = list->item;
 973                 n = list->next;
 974                 free(list);
 975                 list = n;
 976
 977                 flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
 978                 if (flags == (PARENT1 | PARENT2)) {
 979                         if (!(commit->object.flags & RESULT)) {
 980                                 commit->object.flags |= RESULT;
 981                                 insert_by_date(commit, &result);
 982                         }
 983                         /* Mark parents of a found merge stale */
 984                         flags |= STALE;
 985                 }
 986                 parents = commit->parents;
 987                 while (parents) {
 988                         struct commit *p = parents->item;
 989                         parents = parents->next;
 990                         if ((p->object.flags & flags) == flags)
 991                                 continue;
 992                         parse_commit(p);
 993                         p->object.flags |= flags;
 994                         insert_by_date(p, &list);
 995                 }
 996         }
 997
 998         /* Clean up the result to remove stale ones */
 999         list = result; result = NULL;
1000         while (list) {
1001                 struct commit_list *n = list->next;
1002                 if (!(list->item->object.flags & STALE))
1003                         insert_by_date(list->item, &result);
1004                 free(list);
1005                 list = n;
1006         }
1007         return result;
1008 }
1009
1010 struct commit_list *get_merge_bases(struct commit *one,
1011                                     struct commit *two,
1012                                     int cleanup)
1013 {
1014         const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
1015         struct commit_list *list;
1016         struct commit **rslt;
1017         struct commit_list *result;
1018         int cnt, i, j;
1019
1020         result = merge_bases(one, two);
1021         if (one == two)
1022                 return result;
1023         if (!result || !result->next) {
1024                 if (cleanup) {
1025                         clear_commit_marks(one, all_flags);
1026                         clear_commit_marks(two, all_flags);
1027                 }
1028                 return result;
1029         }
1030
1031         /* There are more than one */
1032         cnt = 0;
1033         list = result;
1034         while (list) {
1035                 list = list->next;
1036                 cnt++;
1037         }
1038         rslt = xcalloc(cnt, sizeof(*rslt));
1039         for (list = result, i = 0; list; list = list->next)
1040                 rslt[i++] = list->item;
1041         free_commit_list(result);
1042
1043         clear_commit_marks(one, all_flags);
1044         clear_commit_marks(two, all_flags);
1045         for (i = 0; i < cnt - 1; i++) {
1046                 for (j = i+1; j < cnt; j++) {
1047                         if (!rslt[i] || !rslt[j])
1048                                 continue;
1049                         result = merge_bases(rslt[i], rslt[j]);
1050                         clear_commit_marks(rslt[i], all_flags);
1051                         clear_commit_marks(rslt[j], all_flags);
1052                         for (list = result; list; list = list->next) {
1053                                 if (rslt[i] == list->item)
1054                                         rslt[i] = NULL;
1055                                 if (rslt[j] == list->item)
1056                                         rslt[j] = NULL;
1057                         }
1058                 }
1059         }
1060
1061         /* Surviving ones in rslt[] are the independent results */
1062         result = NULL;
1063         for (i = 0; i < cnt; i++) {
1064                 if (rslt[i])
1065                         insert_by_date(rslt[i], &result);
1066         }
1067         free(rslt);
1068         return result;
1069 }