commit.c

   1 #include "cache.h"
   2 #include "tag.h"
   3 #include "commit.h"
   4 #include "pkt-line.h"
   5 #include "utf8.h"
   6
   7 int save_commit_buffer = 1;
   8
   9 struct sort_node
  10 {
  11         /*
  12          * the number of children of the associated commit
  13          * that also occur in the list being sorted.
  14          */
  15         unsigned int indegree;
  16
  17         /*
  18          * reference to original list item that we will re-use
  19          * on output.
  20          */
  21         struct commit_list * list_item;
  22
  23 };
  24
  25 const char *commit_type = "commit";
  26
  27 struct cmt_fmt_map {
  28         const char *n;
  29         size_t cmp_len;
  30         enum cmit_fmt v;
  31 } cmt_fmts[] = {
  32         { "raw",        1,      CMIT_FMT_RAW },
  33         { "medium",     1,      CMIT_FMT_MEDIUM },
  34         { "short",      1,      CMIT_FMT_SHORT },
  35         { "email",      1,      CMIT_FMT_EMAIL },
  36         { "full",       5,      CMIT_FMT_FULL },
  37         { "fuller",     5,      CMIT_FMT_FULLER },
  38         { "oneline",    1,      CMIT_FMT_ONELINE },
  39 };
  40
  41 enum cmit_fmt get_commit_format(const char *arg)
  42 {
  43         int i;
  44
  45         if (!arg || !*arg)
  46                 return CMIT_FMT_DEFAULT;
  47         if (*arg == '=')
  48                 arg++;
  49         for (i = 0; i < ARRAY_SIZE(cmt_fmts); i++) {
  50                 if (!strncmp(arg, cmt_fmts[i].n, cmt_fmts[i].cmp_len))
  51                         return cmt_fmts[i].v;
  52         }
  53
  54         die("invalid --pretty format: %s", arg);
  55 }
  56
  57 static struct commit *check_commit(struct object *obj,
  58                                    const unsigned char *sha1,
  59                                    int quiet)
  60 {
  61         if (obj->type != OBJ_COMMIT) {
  62                 if (!quiet)
  63                         error("Object %s is a %s, not a commit",
  64                               sha1_to_hex(sha1), typename(obj->type));
  65                 return NULL;
  66         }
  67         return (struct commit *) obj;
  68 }
  69
  70 struct commit *lookup_commit_reference_gently(const unsigned char *sha1,
  71                                               int quiet)
  72 {
  73         struct object *obj = deref_tag(parse_object(sha1), NULL, 0);
  74
  75         if (!obj)
  76                 return NULL;
  77         return check_commit(obj, sha1, quiet);
  78 }
  79
  80 struct commit *lookup_commit_reference(const unsigned char *sha1)
  81 {
  82         return lookup_commit_reference_gently(sha1, 0);
  83 }
  84
  85 struct commit *lookup_commit(const unsigned char *sha1)
  86 {
  87         struct object *obj = lookup_object(sha1);
  88         if (!obj) {
  89                 struct commit *ret = alloc_commit_node();
  90                 created_object(sha1, &ret->object);
  91                 ret->object.type = OBJ_COMMIT;
  92                 return ret;
  93         }
  94         if (!obj->type)
  95                 obj->type = OBJ_COMMIT;
  96         return check_commit(obj, sha1, 0);
  97 }
  98
  99 static unsigned long parse_commit_date(const char *buf)
 100 {
 101         unsigned long date;
 102
 103         if (memcmp(buf, "author", 6))
 104                 return 0;
 105         while (*buf++ != '\n')
 106                 /* nada */;
 107         if (memcmp(buf, "committer", 9))
 108                 return 0;
 109         while (*buf++ != '>')
 110                 /* nada */;
 111         date = strtoul(buf, NULL, 10);
 112         if (date == ULONG_MAX)
 113                 date = 0;
 114         return date;
 115 }
 116
 117 static struct commit_graft **commit_graft;
 118 static int commit_graft_alloc, commit_graft_nr;
 119
 120 static int commit_graft_pos(const unsigned char *sha1)
 121 {
 122         int lo, hi;
 123         lo = 0;
 124         hi = commit_graft_nr;
 125         while (lo < hi) {
 126                 int mi = (lo + hi) / 2;
 127                 struct commit_graft *graft = commit_graft[mi];
 128                 int cmp = hashcmp(sha1, graft->sha1);
 129                 if (!cmp)
 130                         return mi;
 131                 if (cmp < 0)
 132                         hi = mi;
 133                 else
 134                         lo = mi + 1;
 135         }
 136         return -lo - 1;
 137 }
 138
 139 int register_commit_graft(struct commit_graft *graft, int ignore_dups)
 140 {
 141         int pos = commit_graft_pos(graft->sha1);
 142
 143         if (0 <= pos) {
 144                 if (ignore_dups)
 145                         free(graft);
 146                 else {
 147                         free(commit_graft[pos]);
 148                         commit_graft[pos] = graft;
 149                 }
 150                 return 1;
 151         }
 152         pos = -pos - 1;
 153         if (commit_graft_alloc <= ++commit_graft_nr) {
 154                 commit_graft_alloc = alloc_nr(commit_graft_alloc);
 155                 commit_graft = xrealloc(commit_graft,
 156                                         sizeof(*commit_graft) *
 157                                         commit_graft_alloc);
 158         }
 159         if (pos < commit_graft_nr)
 160                 memmove(commit_graft + pos + 1,
 161                         commit_graft + pos,
 162                         (commit_graft_nr - pos - 1) *
 163                         sizeof(*commit_graft));
 164         commit_graft[pos] = graft;
 165         return 0;
 166 }
 167
 168 struct commit_graft *read_graft_line(char *buf, int len)
 169 {
 170         /* The format is just "Commit Parent1 Parent2 ...\n" */
 171         int i;
 172         struct commit_graft *graft = NULL;
 173
 174         if (buf[len-1] == '\n')
 175                 buf[--len] = 0;
 176         if (buf[0] == '#' || buf[0] == '\0')
 177                 return NULL;
 178         if ((len + 1) % 41) {
 179         bad_graft_data:
 180                 error("bad graft data: %s", buf);
 181                 free(graft);
 182                 return NULL;
 183         }
 184         i = (len + 1) / 41 - 1;
 185         graft = xmalloc(sizeof(*graft) + 20 * i);
 186         graft->nr_parent = i;
 187         if (get_sha1_hex(buf, graft->sha1))
 188                 goto bad_graft_data;
 189         for (i = 40; i < len; i += 41) {
 190                 if (buf[i] != ' ')
 191                         goto bad_graft_data;
 192                 if (get_sha1_hex(buf + i + 1, graft->parent[i/41]))
 193                         goto bad_graft_data;
 194         }
 195         return graft;
 196 }
 197
 198 int read_graft_file(const char *graft_file)
 199 {
 200         FILE *fp = fopen(graft_file, "r");
 201         char buf[1024];
 202         if (!fp)
 203                 return -1;
 204         while (fgets(buf, sizeof(buf), fp)) {
 205                 /* The format is just "Commit Parent1 Parent2 ...\n" */
 206                 int len = strlen(buf);
 207                 struct commit_graft *graft = read_graft_line(buf, len);
 208                 if (!graft)
 209                         continue;
 210                 if (register_commit_graft(graft, 1))
 211                         error("duplicate graft data: %s", buf);
 212         }
 213         fclose(fp);
 214         return 0;
 215 }
 216
 217 static void prepare_commit_graft(void)
 218 {
 219         static int commit_graft_prepared;
 220         char *graft_file;
 221
 222         if (commit_graft_prepared)
 223                 return;
 224         graft_file = get_graft_file();
 225         read_graft_file(graft_file);
 226         /* make sure shallows are read */
 227         is_repository_shallow();
 228         commit_graft_prepared = 1;
 229 }
 230
 231 static struct commit_graft *lookup_commit_graft(const unsigned char *sha1)
 232 {
 233         int pos;
 234         prepare_commit_graft();
 235         pos = commit_graft_pos(sha1);
 236         if (pos < 0)
 237                 return NULL;
 238         return commit_graft[pos];
 239 }
 240
 241 int write_shallow_commits(int fd, int use_pack_protocol)
 242 {
 243         int i, count = 0;
 244         for (i = 0; i < commit_graft_nr; i++)
 245                 if (commit_graft[i]->nr_parent < 0) {
 246                         const char *hex =
 247                                 sha1_to_hex(commit_graft[i]->sha1);
 248                         count++;
 249                         if (use_pack_protocol)
 250                                 packet_write(fd, "shallow %s", hex);
 251                         else {
 252                                 write(fd, hex,  40);
 253                                 write(fd, "\n", 1);
 254                         }
 255                 }
 256         return count;
 257 }
 258
 259 int unregister_shallow(const unsigned char *sha1)
 260 {
 261         int pos = commit_graft_pos(sha1);
 262         if (pos < 0)
 263                 return -1;
 264         if (pos + 1 < commit_graft_nr)
 265                 memcpy(commit_graft + pos, commit_graft + pos + 1,
 266                                 sizeof(struct commit_graft *)
 267                                 * (commit_graft_nr - pos - 1));
 268         commit_graft_nr--;
 269         return 0;
 270 }
 271
 272 int parse_commit_buffer(struct commit *item, void *buffer, unsigned long size)
 273 {
 274         char *tail = buffer;
 275         char *bufptr = buffer;
 276         unsigned char parent[20];
 277         struct commit_list **pptr;
 278         struct commit_graft *graft;
 279         unsigned n_refs = 0;
 280
 281         if (item->object.parsed)
 282                 return 0;
 283         item->object.parsed = 1;
 284         tail += size;
 285         if (tail <= bufptr + 5 || memcmp(bufptr, "tree ", 5))
 286                 return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
 287         if (tail <= bufptr + 45 || get_sha1_hex(bufptr + 5, parent) < 0)
 288                 return error("bad tree pointer in commit %s",
 289                              sha1_to_hex(item->object.sha1));
 290         item->tree = lookup_tree(parent);
 291         if (item->tree)
 292                 n_refs++;
 293         bufptr += 46; /* "tree " + "hex sha1" + "\n" */
 294         pptr = &item->parents;
 295
 296         graft = lookup_commit_graft(item->object.sha1);
 297         while (bufptr + 48 < tail && !memcmp(bufptr, "parent ", 7)) {
 298                 struct commit *new_parent;
 299
 300                 if (tail <= bufptr + 48 ||
 301                     get_sha1_hex(bufptr + 7, parent) ||
 302                     bufptr[47] != '\n')
 303                         return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
 304                 bufptr += 48;
 305                 if (graft)
 306                         continue;
 307                 new_parent = lookup_commit(parent);
 308                 if (new_parent) {
 309                         pptr = &commit_list_insert(new_parent, pptr)->next;
 310                         n_refs++;
 311                 }
 312         }
 313         if (graft) {
 314                 int i;
 315                 struct commit *new_parent;
 316                 for (i = 0; i < graft->nr_parent; i++) {
 317                         new_parent = lookup_commit(graft->parent[i]);
 318                         if (!new_parent)
 319                                 continue;
 320                         pptr = &commit_list_insert(new_parent, pptr)->next;
 321                         n_refs++;
 322                 }
 323         }
 324         item->date = parse_commit_date(bufptr);
 325
 326         if (track_object_refs) {
 327                 unsigned i = 0;
 328                 struct commit_list *p;
 329                 struct object_refs *refs = alloc_object_refs(n_refs);
 330                 if (item->tree)
 331                         refs->ref[i++] = &item->tree->object;
 332                 for (p = item->parents; p; p = p->next)
 333                         refs->ref[i++] = &p->item->object;
 334                 set_object_refs(&item->object, refs);
 335         }
 336
 337         return 0;
 338 }
 339
 340 int parse_commit(struct commit *item)
 341 {
 342         char type[20];
 343         void *buffer;
 344         unsigned long size;
 345         int ret;
 346
 347         if (item->object.parsed)
 348                 return 0;
 349         buffer = read_sha1_file(item->object.sha1, type, &size);
 350         if (!buffer)
 351                 return error("Could not read %s",
 352                              sha1_to_hex(item->object.sha1));
 353         if (strcmp(type, commit_type)) {
 354                 free(buffer);
 355                 return error("Object %s not a commit",
 356                              sha1_to_hex(item->object.sha1));
 357         }
 358         ret = parse_commit_buffer(item, buffer, size);
 359         if (save_commit_buffer && !ret) {
 360                 item->buffer = buffer;
 361                 return 0;
 362         }
 363         free(buffer);
 364         return ret;
 365 }
 366
 367 struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
 368 {
 369         struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
 370         new_list->item = item;
 371         new_list->next = *list_p;
 372         *list_p = new_list;
 373         return new_list;
 374 }
 375
 376 void free_commit_list(struct commit_list *list)
 377 {
 378         while (list) {
 379                 struct commit_list *temp = list;
 380                 list = temp->next;
 381                 free(temp);
 382         }
 383 }
 384
 385 struct commit_list * insert_by_date(struct commit *item, struct commit_list **list)
 386 {
 387         struct commit_list **pp = list;
 388         struct commit_list *p;
 389         while ((p = *pp) != NULL) {
 390                 if (p->item->date < item->date) {
 391                         break;
 392                 }
 393                 pp = &p->next;
 394         }
 395         return commit_list_insert(item, pp);
 396 }
 397
 398
 399 void sort_by_date(struct commit_list **list)
 400 {
 401         struct commit_list *ret = NULL;
 402         while (*list) {
 403                 insert_by_date((*list)->item, &ret);
 404                 *list = (*list)->next;
 405         }
 406         *list = ret;
 407 }
 408
 409 struct commit *pop_most_recent_commit(struct commit_list **list,
 410                                       unsigned int mark)
 411 {
 412         struct commit *ret = (*list)->item;
 413         struct commit_list *parents = ret->parents;
 414         struct commit_list *old = *list;
 415
 416         *list = (*list)->next;
 417         free(old);
 418
 419         while (parents) {
 420                 struct commit *commit = parents->item;
 421                 parse_commit(commit);
 422                 if (!(commit->object.flags & mark)) {
 423                         commit->object.flags |= mark;
 424                         insert_by_date(commit, list);
 425                 }
 426                 parents = parents->next;
 427         }
 428         return ret;
 429 }
 430
 431 void clear_commit_marks(struct commit *commit, unsigned int mark)
 432 {
 433         struct commit_list *parents;
 434
 435         commit->object.flags &= ~mark;
 436         parents = commit->parents;
 437         while (parents) {
 438                 struct commit *parent = parents->item;
 439
 440                 /* Have we already cleared this? */
 441                 if (mark & parent->object.flags)
 442                         clear_commit_marks(parent, mark);
 443                 parents = parents->next;
 444         }
 445 }
 446
 447 /*
 448  * Generic support for pretty-printing the header
 449  */
 450 static int get_one_line(const char *msg, unsigned long len)
 451 {
 452         int ret = 0;
 453
 454         while (len--) {
 455                 char c = *msg++;
 456                 if (!c)
 457                         break;
 458                 ret++;
 459                 if (c == '\n')
 460                         break;
 461         }
 462         return ret;
 463 }
 464
 465 static int is_rfc2047_special(char ch)
 466 {
 467         return ((ch & 0x80) || (ch == '=') || (ch == '?') || (ch == '_'));
 468 }
 469
 470 static int add_rfc2047(char *buf, const char *line, int len)
 471 {
 472         char *bp = buf;
 473         int i, needquote;
 474         static const char q_utf8[] = "=?utf-8?q?";
 475
 476         for (i = needquote = 0; !needquote && i < len; i++) {
 477                 unsigned ch = line[i];
 478                 if (ch & 0x80)
 479                         needquote++;
 480                 if ((i + 1 < len) &&
 481                     (ch == '=' && line[i+1] == '?'))
 482                         needquote++;
 483         }
 484         if (!needquote)
 485                 return sprintf(buf, "%.*s", len, line);
 486
 487         memcpy(bp, q_utf8, sizeof(q_utf8)-1);
 488         bp += sizeof(q_utf8)-1;
 489         for (i = 0; i < len; i++) {
 490                 unsigned ch = line[i] & 0xFF;
 491                 if (is_rfc2047_special(ch)) {
 492                         sprintf(bp, "=%02X", ch);
 493                         bp += 3;
 494                 }
 495                 else if (ch == ' ')
 496                         *bp++ = '_';
 497                 else
 498                         *bp++ = ch;
 499         }
 500         memcpy(bp, "?=", 2);
 501         bp += 2;
 502         return bp - buf;
 503 }
 504
 505 static int add_user_info(const char *what, enum cmit_fmt fmt, char *buf,
 506                          const char *line, int relative_date)
 507 {
 508         char *date;
 509         int namelen;
 510         unsigned long time;
 511         int tz, ret;
 512         const char *filler = "    ";
 513
 514         if (fmt == CMIT_FMT_ONELINE)
 515                 return 0;
 516         date = strchr(line, '>');
 517         if (!date)
 518                 return 0;
 519         namelen = ++date - line;
 520         time = strtoul(date, &date, 10);
 521         tz = strtol(date, NULL, 10);
 522
 523         if (fmt == CMIT_FMT_EMAIL) {
 524                 char *name_tail = strchr(line, '<');
 525                 int display_name_length;
 526                 if (!name_tail)
 527                         return 0;
 528                 while (line < name_tail && isspace(name_tail[-1]))
 529                         name_tail--;
 530                 display_name_length = name_tail - line;
 531                 filler = "";
 532                 strcpy(buf, "From: ");
 533                 ret = strlen(buf);
 534                 ret += add_rfc2047(buf + ret, line, display_name_length);
 535                 memcpy(buf + ret, name_tail, namelen - display_name_length);
 536                 ret += namelen - display_name_length;
 537                 buf[ret++] = '\n';
 538         }
 539         else {
 540                 ret = sprintf(buf, "%s: %.*s%.*s\n", what,
 541                               (fmt == CMIT_FMT_FULLER) ? 4 : 0,
 542                               filler, namelen, line);
 543         }
 544         switch (fmt) {
 545         case CMIT_FMT_MEDIUM:
 546                 ret += sprintf(buf + ret, "Date:   %s\n",
 547                                show_date(time, tz, relative_date));
 548                 break;
 549         case CMIT_FMT_EMAIL:
 550                 ret += sprintf(buf + ret, "Date: %s\n",
 551                                show_rfc2822_date(time, tz));
 552                 break;
 553         case CMIT_FMT_FULLER:
 554                 ret += sprintf(buf + ret, "%sDate: %s\n", what,
 555                                show_date(time, tz, relative_date));
 556                 break;
 557         default:
 558                 /* notin' */
 559                 break;
 560         }
 561         return ret;
 562 }
 563
 564 static int is_empty_line(const char *line, int *len_p)
 565 {
 566         int len = *len_p;
 567         while (len && isspace(line[len-1]))
 568                 len--;
 569         *len_p = len;
 570         return !len;
 571 }
 572
 573 static int add_merge_info(enum cmit_fmt fmt, char *buf, const struct commit *commit, int abbrev)
 574 {
 575         struct commit_list *parent = commit->parents;
 576         int offset;
 577
 578         if ((fmt == CMIT_FMT_ONELINE) || (fmt == CMIT_FMT_EMAIL) ||
 579             !parent || !parent->next)
 580                 return 0;
 581
 582         offset = sprintf(buf, "Merge:");
 583
 584         while (parent) {
 585                 struct commit *p = parent->item;
 586                 const char *hex = NULL;
 587                 const char *dots;
 588                 if (abbrev)
 589                         hex = find_unique_abbrev(p->object.sha1, abbrev);
 590                 if (!hex)
 591                         hex = sha1_to_hex(p->object.sha1);
 592                 dots = (abbrev && strlen(hex) != 40) ?  "..." : "";
 593                 parent = parent->next;
 594
 595                 offset += sprintf(buf + offset, " %s%s", hex, dots);
 596         }
 597         buf[offset++] = '\n';
 598         return offset;
 599 }
 600
 601 static char *get_header(const struct commit *commit, const char *key)
 602 {
 603         int key_len = strlen(key);
 604         const char *line = commit->buffer;
 605
 606         for (;;) {
 607                 const char *eol = strchr(line, '\n'), *next;
 608
 609                 if (line == eol)
 610                         return NULL;
 611                 if (!eol) {
 612                         eol = line + strlen(line);
 613                         next = NULL;
 614                 } else
 615                         next = eol + 1;
 616                 if (!strncmp(line, key, key_len) && line[key_len] == ' ') {
 617                         int len = eol - line - key_len;
 618                         char *ret = xmalloc(len);
 619                         memcpy(ret, line + key_len + 1, len - 1);
 620                         ret[len - 1] = '\0';
 621                         return ret;
 622                 }
 623                 line = next;
 624         }
 625 }
 626
 627 static char *replace_encoding_header(char *buf, char *encoding)
 628 {
 629         char *encoding_header = strstr(buf, "\nencoding ");
 630         char *end_of_encoding_header;
 631         int encoding_header_pos;
 632         int encoding_header_len;
 633         int new_len;
 634         int need_len;
 635         int buflen = strlen(buf) + 1;
 636
 637         if (!encoding_header)
 638                 return buf; /* should not happen but be defensive */
 639         encoding_header++;
 640         end_of_encoding_header = strchr(encoding_header, '\n');
 641         if (!end_of_encoding_header)
 642                 return buf; /* should not happen but be defensive */
 643         end_of_encoding_header++;
 644
 645         encoding_header_len = end_of_encoding_header - encoding_header;
 646         encoding_header_pos = encoding_header - buf;
 647
 648         if (is_encoding_utf8(encoding)) {
 649                 /* we have re-coded to UTF-8; drop the header */
 650                 memmove(encoding_header, end_of_encoding_header,
 651                         buflen - (encoding_header_pos + encoding_header_len));
 652                 return buf;
 653         }
 654         new_len = strlen(encoding);
 655         need_len = new_len + strlen("encoding \n");
 656         if (encoding_header_len < need_len) {
 657                 buf = xrealloc(buf, buflen + (need_len - encoding_header_len));
 658                 encoding_header = buf + encoding_header_pos;
 659                 end_of_encoding_header = encoding_header + encoding_header_len;
 660         }
 661         memmove(end_of_encoding_header + (need_len - encoding_header_len),
 662                 end_of_encoding_header,
 663                 buflen - (encoding_header_pos + encoding_header_len));
 664         memcpy(encoding_header + 9, encoding, strlen(encoding));
 665         encoding_header[9 + new_len] = '\n';
 666         return buf;
 667 }
 668
 669 static char *logmsg_reencode(const struct commit *commit)
 670 {
 671         char *encoding;
 672         char *out;
 673         char *output_encoding = (git_log_output_encoding
 674                                  ? git_log_output_encoding
 675                                  : git_commit_encoding);
 676
 677         if (!output_encoding)
 678                 output_encoding = "utf-8";
 679         else if (!*output_encoding)
 680                 return NULL;
 681         encoding = get_header(commit, "encoding");
 682         if (!encoding)
 683                 return NULL;
 684         if (!strcmp(encoding, output_encoding))
 685                 out = strdup(commit->buffer);
 686         else
 687                 out = reencode_string(commit->buffer,
 688                                       output_encoding, encoding);
 689         if (out)
 690                 out = replace_encoding_header(out, output_encoding);
 691
 692         free(encoding);
 693         if (!out)
 694                 return NULL;
 695         return out;
 696 }
 697
 698 unsigned long pretty_print_commit(enum cmit_fmt fmt,
 699                                   const struct commit *commit,
 700                                   unsigned long len,
 701                                   char *buf, unsigned long space,
 702                                   int abbrev, const char *subject,
 703                                   const char *after_subject,
 704                                   int relative_date)
 705 {
 706         int hdr = 1, body = 0, seen_title = 0;
 707         unsigned long offset = 0;
 708         int indent = 4;
 709         int parents_shown = 0;
 710         const char *msg = commit->buffer;
 711         int plain_non_ascii = 0;
 712         char *reencoded = logmsg_reencode(commit);
 713
 714         if (reencoded)
 715                 msg = reencoded;
 716
 717         if (fmt == CMIT_FMT_ONELINE || fmt == CMIT_FMT_EMAIL)
 718                 indent = 0;
 719
 720         /* After-subject is used to pass in Content-Type: multipart
 721          * MIME header; in that case we do not have to do the
 722          * plaintext content type even if the commit message has
 723          * non 7-bit ASCII character.  Otherwise, check if we need
 724          * to say this is not a 7-bit ASCII.
 725          */
 726         if (fmt == CMIT_FMT_EMAIL && !after_subject) {
 727                 int i, ch, in_body;
 728
 729                 for (in_body = i = 0; (ch = msg[i]) && i < len; i++) {
 730                         if (!in_body) {
 731                                 /* author could be non 7-bit ASCII but
 732                                  * the log may be so; skip over the
 733                                  * header part first.
 734                                  */
 735                                 if (ch == '\n' &&
 736                                     i + 1 < len && msg[i+1] == '\n')
 737                                         in_body = 1;
 738                         }
 739                         else if (ch & 0x80) {
 740                                 plain_non_ascii = 1;
 741                                 break;
 742                         }
 743                 }
 744         }
 745
 746         for (;;) {
 747                 const char *line = msg;
 748                 int linelen = get_one_line(msg, len);
 749
 750                 if (!linelen)
 751                         break;
 752
 753                 /*
 754                  * We want some slop for indentation and a possible
 755                  * final "...". Thus the "+ 20".
 756                  */
 757                 if (offset + linelen + 20 > space) {
 758                         memcpy(buf + offset, "    ...\n", 8);
 759                         offset += 8;
 760                         break;
 761                 }
 762
 763                 msg += linelen;
 764                 len -= linelen;
 765                 if (hdr) {
 766                         if (linelen == 1) {
 767                                 hdr = 0;
 768                                 if ((fmt != CMIT_FMT_ONELINE) && !subject)
 769                                         buf[offset++] = '\n';
 770                                 continue;
 771                         }
 772                         if (fmt == CMIT_FMT_RAW) {
 773                                 memcpy(buf + offset, line, linelen);
 774                                 offset += linelen;
 775                                 continue;
 776                         }
 777                         if (!memcmp(line, "parent ", 7)) {
 778                                 if (linelen != 48)
 779                                         die("bad parent line in commit");
 780                                 continue;
 781                         }
 782
 783                         if (!parents_shown) {
 784                                 offset += add_merge_info(fmt, buf + offset,
 785                                                          commit, abbrev);
 786                                 parents_shown = 1;
 787                                 continue;
 788                         }
 789                         /*
 790                          * MEDIUM == DEFAULT shows only author with dates.
 791                          * FULL shows both authors but not dates.
 792                          * FULLER shows both authors and dates.
 793                          */
 794                         if (!memcmp(line, "author ", 7))
 795                                 offset += add_user_info("Author", fmt,
 796                                                         buf + offset,
 797                                                         line + 7,
 798                                                         relative_date);
 799                         if (!memcmp(line, "committer ", 10) &&
 800                             (fmt == CMIT_FMT_FULL || fmt == CMIT_FMT_FULLER))
 801                                 offset += add_user_info("Commit", fmt,
 802                                                         buf + offset,
 803                                                         line + 10,
 804                                                         relative_date);
 805                         continue;
 806                 }
 807
 808                 if (!subject)
 809                         body = 1;
 810
 811                 if (is_empty_line(line, &linelen)) {
 812                         if (!seen_title)
 813                                 continue;
 814                         if (!body)
 815                                 continue;
 816                         if (subject)
 817                                 continue;
 818                         if (fmt == CMIT_FMT_SHORT)
 819                                 break;
 820                 }
 821
 822                 seen_title = 1;
 823                 if (subject) {
 824                         int slen = strlen(subject);
 825                         memcpy(buf + offset, subject, slen);
 826                         offset += slen;
 827                         offset += add_rfc2047(buf + offset, line, linelen);
 828                 }
 829                 else {
 830                         memset(buf + offset, ' ', indent);
 831                         memcpy(buf + offset + indent, line, linelen);
 832                         offset += linelen + indent;
 833                 }
 834                 buf[offset++] = '\n';
 835                 if (fmt == CMIT_FMT_ONELINE)
 836                         break;
 837                 if (subject && plain_non_ascii) {
 838                         static const char header[] =
 839                                 "Content-Type: text/plain; charset=UTF-8\n"
 840                                 "Content-Transfer-Encoding: 8bit\n";
 841                         memcpy(buf + offset, header, sizeof(header)-1);
 842                         offset += sizeof(header)-1;
 843                 }
 844                 if (after_subject) {
 845                         int slen = strlen(after_subject);
 846                         if (slen > space - offset - 1)
 847                                 slen = space - offset - 1;
 848                         memcpy(buf + offset, after_subject, slen);
 849                         offset += slen;
 850                         after_subject = NULL;
 851                 }
 852                 subject = NULL;
 853         }
 854         while (offset && isspace(buf[offset-1]))
 855                 offset--;
 856         /* Make sure there is an EOLN for the non-oneline case */
 857         if (fmt != CMIT_FMT_ONELINE)
 858                 buf[offset++] = '\n';
 859         /*
 860          * make sure there is another EOLN to separate the headers from whatever
 861          * body the caller appends if we haven't already written a body
 862          */
 863         if (fmt == CMIT_FMT_EMAIL && !body)
 864                 buf[offset++] = '\n';
 865         buf[offset] = '\0';
 866
 867         free(reencoded);
 868         return offset;
 869 }
 870
 871 struct commit *pop_commit(struct commit_list **stack)
 872 {
 873         struct commit_list *top = *stack;
 874         struct commit *item = top ? top->item : NULL;
 875
 876         if (top) {
 877                 *stack = top->next;
 878                 free(top);
 879         }
 880         return item;
 881 }
 882
 883 int count_parents(struct commit * commit)
 884 {
 885         int count;
 886         struct commit_list * parents = commit->parents;
 887         for (count = 0; parents; parents = parents->next,count++)
 888                 ;
 889         return count;
 890 }
 891
 892 void topo_sort_default_setter(struct commit *c, void *data)
 893 {
 894         c->util = data;
 895 }
 896
 897 void *topo_sort_default_getter(struct commit *c)
 898 {
 899         return c->util;
 900 }
 901
 902 /*
 903  * Performs an in-place topological sort on the list supplied.
 904  */
 905 void sort_in_topological_order(struct commit_list ** list, int lifo)
 906 {
 907         sort_in_topological_order_fn(list, lifo, topo_sort_default_setter,
 908                                      topo_sort_default_getter);
 909 }
 910
 911 void sort_in_topological_order_fn(struct commit_list ** list, int lifo,
 912                                   topo_sort_set_fn_t setter,
 913                                   topo_sort_get_fn_t getter)
 914 {
 915         struct commit_list * next = *list;
 916         struct commit_list * work = NULL, **insert;
 917         struct commit_list ** pptr = list;
 918         struct sort_node * nodes;
 919         struct sort_node * next_nodes;
 920         int count = 0;
 921
 922         /* determine the size of the list */
 923         while (next) {
 924                 next = next->next;
 925                 count++;
 926         }
 927
 928         if (!count)
 929                 return;
 930         /* allocate an array to help sort the list */
 931         nodes = xcalloc(count, sizeof(*nodes));
 932         /* link the list to the array */
 933         next_nodes = nodes;
 934         next=*list;
 935         while (next) {
 936                 next_nodes->list_item = next;
 937                 setter(next->item, next_nodes);
 938                 next_nodes++;
 939                 next = next->next;
 940         }
 941         /* update the indegree */
 942         next=*list;
 943         while (next) {
 944                 struct commit_list * parents = next->item->parents;
 945                 while (parents) {
 946                         struct commit * parent=parents->item;
 947                         struct sort_node * pn = (struct sort_node *) getter(parent);
 948
 949                         if (pn)
 950                                 pn->indegree++;
 951                         parents=parents->next;
 952                 }
 953                 next=next->next;
 954         }
 955         /*
 956          * find the tips
 957          *
 958          * tips are nodes not reachable from any other node in the list
 959          *
 960          * the tips serve as a starting set for the work queue.
 961          */
 962         next=*list;
 963         insert = &work;
 964         while (next) {
 965                 struct sort_node * node = (struct sort_node *) getter(next->item);
 966
 967                 if (node->indegree == 0) {
 968                         insert = &commit_list_insert(next->item, insert)->next;
 969                 }
 970                 next=next->next;
 971         }
 972
 973         /* process the list in topological order */
 974         if (!lifo)
 975                 sort_by_date(&work);
 976         while (work) {
 977                 struct commit * work_item = pop_commit(&work);
 978                 struct sort_node * work_node = (struct sort_node *) getter(work_item);
 979                 struct commit_list * parents = work_item->parents;
 980
 981                 while (parents) {
 982                         struct commit * parent=parents->item;
 983                         struct sort_node * pn = (struct sort_node *) getter(parent);
 984
 985                         if (pn) {
 986                                 /*
 987                                  * parents are only enqueued for emission
 988                                  * when all their children have been emitted thereby
 989                                  * guaranteeing topological order.
 990                                  */
 991                                 pn->indegree--;
 992                                 if (!pn->indegree) {
 993                                         if (!lifo)
 994                                                 insert_by_date(parent, &work);
 995                                         else
 996                                                 commit_list_insert(parent, &work);
 997                                 }
 998                         }
 999                         parents=parents->next;
1000                 }
1001                 /*
1002                  * work_item is a commit all of whose children
1003                  * have already been emitted. we can emit it now.
1004                  */
1005                 *pptr = work_node->list_item;
1006                 pptr = &(*pptr)->next;
1007                 *pptr = NULL;
1008                 setter(work_item, NULL);
1009         }
1010         free(nodes);
1011 }
1012
1013 /* merge-rebase stuff */
1014
1015 /* bits #0..15 in revision.h */
1016 #define PARENT1         (1u<<16)
1017 #define PARENT2         (1u<<17)
1018 #define STALE           (1u<<18)
1019 #define RESULT          (1u<<19)
1020
1021 static struct commit *interesting(struct commit_list *list)
1022 {
1023         while (list) {
1024                 struct commit *commit = list->item;
1025                 list = list->next;
1026                 if (commit->object.flags & STALE)
1027                         continue;
1028                 return commit;
1029         }
1030         return NULL;
1031 }
1032
1033 static struct commit_list *merge_bases(struct commit *one, struct commit *two)
1034 {
1035         struct commit_list *list = NULL;
1036         struct commit_list *result = NULL;
1037
1038         if (one == two)
1039                 /* We do not mark this even with RESULT so we do not
1040                  * have to clean it up.
1041                  */
1042                 return commit_list_insert(one, &result);
1043
1044         parse_commit(one);
1045         parse_commit(two);
1046
1047         one->object.flags |= PARENT1;
1048         two->object.flags |= PARENT2;
1049         insert_by_date(one, &list);
1050         insert_by_date(two, &list);
1051
1052         while (interesting(list)) {
1053                 struct commit *commit;
1054                 struct commit_list *parents;
1055                 struct commit_list *n;
1056                 int flags;
1057
1058                 commit = list->item;
1059                 n = list->next;
1060                 free(list);
1061                 list = n;
1062
1063                 flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
1064                 if (flags == (PARENT1 | PARENT2)) {
1065                         if (!(commit->object.flags & RESULT)) {
1066                                 commit->object.flags |= RESULT;
1067                                 insert_by_date(commit, &result);
1068                         }
1069                         /* Mark parents of a found merge stale */
1070                         flags |= STALE;
1071                 }
1072                 parents = commit->parents;
1073                 while (parents) {
1074                         struct commit *p = parents->item;
1075                         parents = parents->next;
1076                         if ((p->object.flags & flags) == flags)
1077                                 continue;
1078                         parse_commit(p);
1079                         p->object.flags |= flags;
1080                         insert_by_date(p, &list);
1081                 }
1082         }
1083
1084         /* Clean up the result to remove stale ones */
1085         list = result; result = NULL;
1086         while (list) {
1087                 struct commit_list *n = list->next;
1088                 if (!(list->item->object.flags & STALE))
1089                         insert_by_date(list->item, &result);
1090                 free(list);
1091                 list = n;
1092         }
1093         return result;
1094 }
1095
1096 struct commit_list *get_merge_bases(struct commit *one,
1097                                     struct commit *two,
1098                                     int cleanup)
1099 {
1100         const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
1101         struct commit_list *list;
1102         struct commit **rslt;
1103         struct commit_list *result;
1104         int cnt, i, j;
1105
1106         result = merge_bases(one, two);
1107         if (one == two)
1108                 return result;
1109         if (!result || !result->next) {
1110                 if (cleanup) {
1111                         clear_commit_marks(one, all_flags);
1112                         clear_commit_marks(two, all_flags);
1113                 }
1114                 return result;
1115         }
1116
1117         /* There are more than one */
1118         cnt = 0;
1119         list = result;
1120         while (list) {
1121                 list = list->next;
1122                 cnt++;
1123         }
1124         rslt = xcalloc(cnt, sizeof(*rslt));
1125         for (list = result, i = 0; list; list = list->next)
1126                 rslt[i++] = list->item;
1127         free_commit_list(result);
1128
1129         clear_commit_marks(one, all_flags);
1130         clear_commit_marks(two, all_flags);
1131         for (i = 0; i < cnt - 1; i++) {
1132                 for (j = i+1; j < cnt; j++) {
1133                         if (!rslt[i] || !rslt[j])
1134                                 continue;
1135                         result = merge_bases(rslt[i], rslt[j]);
1136                         clear_commit_marks(rslt[i], all_flags);
1137                         clear_commit_marks(rslt[j], all_flags);
1138                         for (list = result; list; list = list->next) {
1139                                 if (rslt[i] == list->item)
1140                                         rslt[i] = NULL;
1141                                 if (rslt[j] == list->item)
1142                                         rslt[j] = NULL;
1143                         }
1144                 }
1145         }
1146
1147         /* Surviving ones in rslt[] are the independent results */
1148         result = NULL;
1149         for (i = 0; i < cnt; i++) {
1150                 if (rslt[i])
1151                         insert_by_date(rslt[i], &result);
1152         }
1153         free(rslt);
1154         return result;
1155 }
1156
1157 int in_merge_bases(struct commit *rev1, struct commit *rev2)
1158 {
1159         struct commit_list *bases, *b;
1160         int ret = 0;
1161
1162         bases = get_merge_bases(rev1, rev2, 1);
1163         for (b = bases; b; b = b->next) {
1164                 if (!hashcmp(rev1->object.sha1, b->item->object.sha1)) {
1165                         ret = 1;
1166                         break;
1167                 }
1168         }
1169
1170         free_commit_list(bases);
1171         return ret;
1172 }