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                                 if (write_in_full(fd, hex,  40) != 40)
 253                                         break;
 254                                 if (write_in_full(fd, "\n", 1) != 1)
 255                                         break;
 256                         }
 257                 }
 258         return count;
 259 }
 260
 261 int unregister_shallow(const unsigned char *sha1)
 262 {
 263         int pos = commit_graft_pos(sha1);
 264         if (pos < 0)
 265                 return -1;
 266         if (pos + 1 < commit_graft_nr)
 267                 memcpy(commit_graft + pos, commit_graft + pos + 1,
 268                                 sizeof(struct commit_graft *)
 269                                 * (commit_graft_nr - pos - 1));
 270         commit_graft_nr--;
 271         return 0;
 272 }
 273
 274 int parse_commit_buffer(struct commit *item, void *buffer, unsigned long size)
 275 {
 276         char *tail = buffer;
 277         char *bufptr = buffer;
 278         unsigned char parent[20];
 279         struct commit_list **pptr;
 280         struct commit_graft *graft;
 281         unsigned n_refs = 0;
 282
 283         if (item->object.parsed)
 284                 return 0;
 285         item->object.parsed = 1;
 286         tail += size;
 287         if (tail <= bufptr + 5 || memcmp(bufptr, "tree ", 5))
 288                 return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
 289         if (tail <= bufptr + 45 || get_sha1_hex(bufptr + 5, parent) < 0)
 290                 return error("bad tree pointer in commit %s",
 291                              sha1_to_hex(item->object.sha1));
 292         item->tree = lookup_tree(parent);
 293         if (item->tree)
 294                 n_refs++;
 295         bufptr += 46; /* "tree " + "hex sha1" + "\n" */
 296         pptr = &item->parents;
 297
 298         graft = lookup_commit_graft(item->object.sha1);
 299         while (bufptr + 48 < tail && !memcmp(bufptr, "parent ", 7)) {
 300                 struct commit *new_parent;
 301
 302                 if (tail <= bufptr + 48 ||
 303                     get_sha1_hex(bufptr + 7, parent) ||
 304                     bufptr[47] != '\n')
 305                         return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
 306                 bufptr += 48;
 307                 if (graft)
 308                         continue;
 309                 new_parent = lookup_commit(parent);
 310                 if (new_parent) {
 311                         pptr = &commit_list_insert(new_parent, pptr)->next;
 312                         n_refs++;
 313                 }
 314         }
 315         if (graft) {
 316                 int i;
 317                 struct commit *new_parent;
 318                 for (i = 0; i < graft->nr_parent; i++) {
 319                         new_parent = lookup_commit(graft->parent[i]);
 320                         if (!new_parent)
 321                                 continue;
 322                         pptr = &commit_list_insert(new_parent, pptr)->next;
 323                         n_refs++;
 324                 }
 325         }
 326         item->date = parse_commit_date(bufptr);
 327
 328         if (track_object_refs) {
 329                 unsigned i = 0;
 330                 struct commit_list *p;
 331                 struct object_refs *refs = alloc_object_refs(n_refs);
 332                 if (item->tree)
 333                         refs->ref[i++] = &item->tree->object;
 334                 for (p = item->parents; p; p = p->next)
 335                         refs->ref[i++] = &p->item->object;
 336                 set_object_refs(&item->object, refs);
 337         }
 338
 339         return 0;
 340 }
 341
 342 int parse_commit(struct commit *item)
 343 {
 344         char type[20];
 345         void *buffer;
 346         unsigned long size;
 347         int ret;
 348
 349         if (item->object.parsed)
 350                 return 0;
 351         buffer = read_sha1_file(item->object.sha1, type, &size);
 352         if (!buffer)
 353                 return error("Could not read %s",
 354                              sha1_to_hex(item->object.sha1));
 355         if (strcmp(type, commit_type)) {
 356                 free(buffer);
 357                 return error("Object %s not a commit",
 358                              sha1_to_hex(item->object.sha1));
 359         }
 360         ret = parse_commit_buffer(item, buffer, size);
 361         if (save_commit_buffer && !ret) {
 362                 item->buffer = buffer;
 363                 return 0;
 364         }
 365         free(buffer);
 366         return ret;
 367 }
 368
 369 struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
 370 {
 371         struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
 372         new_list->item = item;
 373         new_list->next = *list_p;
 374         *list_p = new_list;
 375         return new_list;
 376 }
 377
 378 void free_commit_list(struct commit_list *list)
 379 {
 380         while (list) {
 381                 struct commit_list *temp = list;
 382                 list = temp->next;
 383                 free(temp);
 384         }
 385 }
 386
 387 struct commit_list * insert_by_date(struct commit *item, struct commit_list **list)
 388 {
 389         struct commit_list **pp = list;
 390         struct commit_list *p;
 391         while ((p = *pp) != NULL) {
 392                 if (p->item->date < item->date) {
 393                         break;
 394                 }
 395                 pp = &p->next;
 396         }
 397         return commit_list_insert(item, pp);
 398 }
 399
 400
 401 void sort_by_date(struct commit_list **list)
 402 {
 403         struct commit_list *ret = NULL;
 404         while (*list) {
 405                 insert_by_date((*list)->item, &ret);
 406                 *list = (*list)->next;
 407         }
 408         *list = ret;
 409 }
 410
 411 struct commit *pop_most_recent_commit(struct commit_list **list,
 412                                       unsigned int mark)
 413 {
 414         struct commit *ret = (*list)->item;
 415         struct commit_list *parents = ret->parents;
 416         struct commit_list *old = *list;
 417
 418         *list = (*list)->next;
 419         free(old);
 420
 421         while (parents) {
 422                 struct commit *commit = parents->item;
 423                 parse_commit(commit);
 424                 if (!(commit->object.flags & mark)) {
 425                         commit->object.flags |= mark;
 426                         insert_by_date(commit, list);
 427                 }
 428                 parents = parents->next;
 429         }
 430         return ret;
 431 }
 432
 433 void clear_commit_marks(struct commit *commit, unsigned int mark)
 434 {
 435         struct commit_list *parents;
 436
 437         commit->object.flags &= ~mark;
 438         parents = commit->parents;
 439         while (parents) {
 440                 struct commit *parent = parents->item;
 441
 442                 /* Have we already cleared this? */
 443                 if (mark & parent->object.flags)
 444                         clear_commit_marks(parent, mark);
 445                 parents = parents->next;
 446         }
 447 }
 448
 449 /*
 450  * Generic support for pretty-printing the header
 451  */
 452 static int get_one_line(const char *msg, unsigned long len)
 453 {
 454         int ret = 0;
 455
 456         while (len--) {
 457                 char c = *msg++;
 458                 if (!c)
 459                         break;
 460                 ret++;
 461                 if (c == '\n')
 462                         break;
 463         }
 464         return ret;
 465 }
 466
 467 /* High bit set, or ISO-2022-INT */
 468 static int non_ascii(int ch)
 469 {
 470         ch = (ch & 0xff);
 471         return ((ch & 0x80) || (ch == 0x1b));
 472 }
 473
 474 static int is_rfc2047_special(char ch)
 475 {
 476         return (non_ascii(ch) || (ch == '=') || (ch == '?') || (ch == '_'));
 477 }
 478
 479 static int add_rfc2047(char *buf, const char *line, int len,
 480                        const char *encoding)
 481 {
 482         char *bp = buf;
 483         int i, needquote;
 484         char q_encoding[128];
 485         const char *q_encoding_fmt = "=?%s?q?";
 486
 487         for (i = needquote = 0; !needquote && i < len; i++) {
 488                 int ch = line[i];
 489                 if (non_ascii(ch))
 490                         needquote++;
 491                 if ((i + 1 < len) &&
 492                     (ch == '=' && line[i+1] == '?'))
 493                         needquote++;
 494         }
 495         if (!needquote)
 496                 return sprintf(buf, "%.*s", len, line);
 497
 498         i = snprintf(q_encoding, sizeof(q_encoding), q_encoding_fmt, encoding);
 499         if (sizeof(q_encoding) < i)
 500                 die("Insanely long encoding name %s", encoding);
 501         memcpy(bp, q_encoding, i);
 502         bp += i;
 503         for (i = 0; i < len; i++) {
 504                 unsigned ch = line[i] & 0xFF;
 505                 if (is_rfc2047_special(ch)) {
 506                         sprintf(bp, "=%02X", ch);
 507                         bp += 3;
 508                 }
 509                 else if (ch == ' ')
 510                         *bp++ = '_';
 511                 else
 512                         *bp++ = ch;
 513         }
 514         memcpy(bp, "?=", 2);
 515         bp += 2;
 516         return bp - buf;
 517 }
 518
 519 static int add_user_info(const char *what, enum cmit_fmt fmt, char *buf,
 520                          const char *line, int relative_date,
 521                          const char *encoding)
 522 {
 523         char *date;
 524         int namelen;
 525         unsigned long time;
 526         int tz, ret;
 527         const char *filler = "    ";
 528
 529         if (fmt == CMIT_FMT_ONELINE)
 530                 return 0;
 531         date = strchr(line, '>');
 532         if (!date)
 533                 return 0;
 534         namelen = ++date - line;
 535         time = strtoul(date, &date, 10);
 536         tz = strtol(date, NULL, 10);
 537
 538         if (fmt == CMIT_FMT_EMAIL) {
 539                 char *name_tail = strchr(line, '<');
 540                 int display_name_length;
 541                 if (!name_tail)
 542                         return 0;
 543                 while (line < name_tail && isspace(name_tail[-1]))
 544                         name_tail--;
 545                 display_name_length = name_tail - line;
 546                 filler = "";
 547                 strcpy(buf, "From: ");
 548                 ret = strlen(buf);
 549                 ret += add_rfc2047(buf + ret, line, display_name_length,
 550                                    encoding);
 551                 memcpy(buf + ret, name_tail, namelen - display_name_length);
 552                 ret += namelen - display_name_length;
 553                 buf[ret++] = '\n';
 554         }
 555         else {
 556                 ret = sprintf(buf, "%s: %.*s%.*s\n", what,
 557                               (fmt == CMIT_FMT_FULLER) ? 4 : 0,
 558                               filler, namelen, line);
 559         }
 560         switch (fmt) {
 561         case CMIT_FMT_MEDIUM:
 562                 ret += sprintf(buf + ret, "Date:   %s\n",
 563                                show_date(time, tz, relative_date));
 564                 break;
 565         case CMIT_FMT_EMAIL:
 566                 ret += sprintf(buf + ret, "Date: %s\n",
 567                                show_rfc2822_date(time, tz));
 568                 break;
 569         case CMIT_FMT_FULLER:
 570                 ret += sprintf(buf + ret, "%sDate: %s\n", what,
 571                                show_date(time, tz, relative_date));
 572                 break;
 573         default:
 574                 /* notin' */
 575                 break;
 576         }
 577         return ret;
 578 }
 579
 580 static int is_empty_line(const char *line, int *len_p)
 581 {
 582         int len = *len_p;
 583         while (len && isspace(line[len-1]))
 584                 len--;
 585         *len_p = len;
 586         return !len;
 587 }
 588
 589 static int add_merge_info(enum cmit_fmt fmt, char *buf, const struct commit *commit, int abbrev)
 590 {
 591         struct commit_list *parent = commit->parents;
 592         int offset;
 593
 594         if ((fmt == CMIT_FMT_ONELINE) || (fmt == CMIT_FMT_EMAIL) ||
 595             !parent || !parent->next)
 596                 return 0;
 597
 598         offset = sprintf(buf, "Merge:");
 599
 600         while (parent) {
 601                 struct commit *p = parent->item;
 602                 const char *hex = NULL;
 603                 const char *dots;
 604                 if (abbrev)
 605                         hex = find_unique_abbrev(p->object.sha1, abbrev);
 606                 if (!hex)
 607                         hex = sha1_to_hex(p->object.sha1);
 608                 dots = (abbrev && strlen(hex) != 40) ?  "..." : "";
 609                 parent = parent->next;
 610
 611                 offset += sprintf(buf + offset, " %s%s", hex, dots);
 612         }
 613         buf[offset++] = '\n';
 614         return offset;
 615 }
 616
 617 static char *get_header(const struct commit *commit, const char *key)
 618 {
 619         int key_len = strlen(key);
 620         const char *line = commit->buffer;
 621
 622         for (;;) {
 623                 const char *eol = strchr(line, '\n'), *next;
 624
 625                 if (line == eol)
 626                         return NULL;
 627                 if (!eol) {
 628                         eol = line + strlen(line);
 629                         next = NULL;
 630                 } else
 631                         next = eol + 1;
 632                 if (!strncmp(line, key, key_len) && line[key_len] == ' ') {
 633                         int len = eol - line - key_len;
 634                         char *ret = xmalloc(len);
 635                         memcpy(ret, line + key_len + 1, len - 1);
 636                         ret[len - 1] = '\0';
 637                         return ret;
 638                 }
 639                 line = next;
 640         }
 641 }
 642
 643 static char *replace_encoding_header(char *buf, char *encoding)
 644 {
 645         char *encoding_header = strstr(buf, "\nencoding ");
 646         char *end_of_encoding_header;
 647         int encoding_header_pos;
 648         int encoding_header_len;
 649         int new_len;
 650         int need_len;
 651         int buflen = strlen(buf) + 1;
 652
 653         if (!encoding_header)
 654                 return buf; /* should not happen but be defensive */
 655         encoding_header++;
 656         end_of_encoding_header = strchr(encoding_header, '\n');
 657         if (!end_of_encoding_header)
 658                 return buf; /* should not happen but be defensive */
 659         end_of_encoding_header++;
 660
 661         encoding_header_len = end_of_encoding_header - encoding_header;
 662         encoding_header_pos = encoding_header - buf;
 663
 664         if (is_encoding_utf8(encoding)) {
 665                 /* we have re-coded to UTF-8; drop the header */
 666                 memmove(encoding_header, end_of_encoding_header,
 667                         buflen - (encoding_header_pos + encoding_header_len));
 668                 return buf;
 669         }
 670         new_len = strlen(encoding);
 671         need_len = new_len + strlen("encoding \n");
 672         if (encoding_header_len < need_len) {
 673                 buf = xrealloc(buf, buflen + (need_len - encoding_header_len));
 674                 encoding_header = buf + encoding_header_pos;
 675                 end_of_encoding_header = encoding_header + encoding_header_len;
 676         }
 677         memmove(end_of_encoding_header + (need_len - encoding_header_len),
 678                 end_of_encoding_header,
 679                 buflen - (encoding_header_pos + encoding_header_len));
 680         memcpy(encoding_header + 9, encoding, strlen(encoding));
 681         encoding_header[9 + new_len] = '\n';
 682         return buf;
 683 }
 684
 685 static char *logmsg_reencode(const struct commit *commit,
 686                              char *output_encoding)
 687 {
 688         char *encoding;
 689         char *out;
 690         char *utf8 = "utf-8";
 691
 692         if (!*output_encoding)
 693                 return NULL;
 694         encoding = get_header(commit, "encoding");
 695         if (!encoding)
 696                 encoding = utf8;
 697         if (!strcmp(encoding, output_encoding))
 698                 out = strdup(commit->buffer);
 699         else
 700                 out = reencode_string(commit->buffer,
 701                                       output_encoding, encoding);
 702         if (out)
 703                 out = replace_encoding_header(out, output_encoding);
 704
 705         if (encoding != utf8)
 706                 free(encoding);
 707         if (!out)
 708                 return NULL;
 709         return out;
 710 }
 711
 712 unsigned long pretty_print_commit(enum cmit_fmt fmt,
 713                                   const struct commit *commit,
 714                                   unsigned long len,
 715                                   char *buf, unsigned long space,
 716                                   int abbrev, const char *subject,
 717                                   const char *after_subject,
 718                                   int relative_date)
 719 {
 720         int hdr = 1, body = 0, seen_title = 0;
 721         unsigned long offset = 0;
 722         int indent = 4;
 723         int parents_shown = 0;
 724         const char *msg = commit->buffer;
 725         int plain_non_ascii = 0;
 726         char *reencoded;
 727         char *encoding;
 728
 729         encoding = (git_log_output_encoding
 730                     ? git_log_output_encoding
 731                     : git_commit_encoding);
 732         if (!encoding)
 733                 encoding = "utf-8";
 734         reencoded = logmsg_reencode(commit, encoding);
 735         if (reencoded)
 736                 msg = reencoded;
 737
 738         if (fmt == CMIT_FMT_ONELINE || fmt == CMIT_FMT_EMAIL)
 739                 indent = 0;
 740
 741         /* After-subject is used to pass in Content-Type: multipart
 742          * MIME header; in that case we do not have to do the
 743          * plaintext content type even if the commit message has
 744          * non 7-bit ASCII character.  Otherwise, check if we need
 745          * to say this is not a 7-bit ASCII.
 746          */
 747         if (fmt == CMIT_FMT_EMAIL && !after_subject) {
 748                 int i, ch, in_body;
 749
 750                 for (in_body = i = 0; (ch = msg[i]) && i < len; i++) {
 751                         if (!in_body) {
 752                                 /* author could be non 7-bit ASCII but
 753                                  * the log may be so; skip over the
 754                                  * header part first.
 755                                  */
 756                                 if (ch == '\n' &&
 757                                     i + 1 < len && msg[i+1] == '\n')
 758                                         in_body = 1;
 759                         }
 760                         else if (non_ascii(ch)) {
 761                                 plain_non_ascii = 1;
 762                                 break;
 763                         }
 764                 }
 765         }
 766
 767         for (;;) {
 768                 const char *line = msg;
 769                 int linelen = get_one_line(msg, len);
 770
 771                 if (!linelen)
 772                         break;
 773
 774                 /*
 775                  * We want some slop for indentation and a possible
 776                  * final "...". Thus the "+ 20".
 777                  */
 778                 if (offset + linelen + 20 > space) {
 779                         memcpy(buf + offset, "    ...\n", 8);
 780                         offset += 8;
 781                         break;
 782                 }
 783
 784                 msg += linelen;
 785                 len -= linelen;
 786                 if (hdr) {
 787                         if (linelen == 1) {
 788                                 hdr = 0;
 789                                 if ((fmt != CMIT_FMT_ONELINE) && !subject)
 790                                         buf[offset++] = '\n';
 791                                 continue;
 792                         }
 793                         if (fmt == CMIT_FMT_RAW) {
 794                                 memcpy(buf + offset, line, linelen);
 795                                 offset += linelen;
 796                                 continue;
 797                         }
 798                         if (!memcmp(line, "parent ", 7)) {
 799                                 if (linelen != 48)
 800                                         die("bad parent line in commit");
 801                                 continue;
 802                         }
 803
 804                         if (!parents_shown) {
 805                                 offset += add_merge_info(fmt, buf + offset,
 806                                                          commit, abbrev);
 807                                 parents_shown = 1;
 808                                 continue;
 809                         }
 810                         /*
 811                          * MEDIUM == DEFAULT shows only author with dates.
 812                          * FULL shows both authors but not dates.
 813                          * FULLER shows both authors and dates.
 814                          */
 815                         if (!memcmp(line, "author ", 7))
 816                                 offset += add_user_info("Author", fmt,
 817                                                         buf + offset,
 818                                                         line + 7,
 819                                                         relative_date,
 820                                                         encoding);
 821                         if (!memcmp(line, "committer ", 10) &&
 822                             (fmt == CMIT_FMT_FULL || fmt == CMIT_FMT_FULLER))
 823                                 offset += add_user_info("Commit", fmt,
 824                                                         buf + offset,
 825                                                         line + 10,
 826                                                         relative_date,
 827                                                         encoding);
 828                         continue;
 829                 }
 830
 831                 if (!subject)
 832                         body = 1;
 833
 834                 if (is_empty_line(line, &linelen)) {
 835                         if (!seen_title)
 836                                 continue;
 837                         if (!body)
 838                                 continue;
 839                         if (subject)
 840                                 continue;
 841                         if (fmt == CMIT_FMT_SHORT)
 842                                 break;
 843                 }
 844
 845                 seen_title = 1;
 846                 if (subject) {
 847                         int slen = strlen(subject);
 848                         memcpy(buf + offset, subject, slen);
 849                         offset += slen;
 850                         offset += add_rfc2047(buf + offset, line, linelen,
 851                                               encoding);
 852                 }
 853                 else {
 854                         memset(buf + offset, ' ', indent);
 855                         memcpy(buf + offset + indent, line, linelen);
 856                         offset += linelen + indent;
 857                 }
 858                 buf[offset++] = '\n';
 859                 if (fmt == CMIT_FMT_ONELINE)
 860                         break;
 861                 if (subject && plain_non_ascii) {
 862                         int sz;
 863                         char header[512];
 864                         const char *header_fmt =
 865                                 "Content-Type: text/plain; charset=%s\n"
 866                                 "Content-Transfer-Encoding: 8bit\n";
 867                         sz = snprintf(header, sizeof(header), header_fmt,
 868                                       encoding);
 869                         if (sizeof(header) < sz)
 870                                 die("Encoding name %s too long", encoding);
 871                         memcpy(buf + offset, header, sz);
 872                         offset += sz;
 873                 }
 874                 if (after_subject) {
 875                         int slen = strlen(after_subject);
 876                         if (slen > space - offset - 1)
 877                                 slen = space - offset - 1;
 878                         memcpy(buf + offset, after_subject, slen);
 879                         offset += slen;
 880                         after_subject = NULL;
 881                 }
 882                 subject = NULL;
 883         }
 884         while (offset && isspace(buf[offset-1]))
 885                 offset--;
 886         /* Make sure there is an EOLN for the non-oneline case */
 887         if (fmt != CMIT_FMT_ONELINE)
 888                 buf[offset++] = '\n';
 889         /*
 890          * make sure there is another EOLN to separate the headers from whatever
 891          * body the caller appends if we haven't already written a body
 892          */
 893         if (fmt == CMIT_FMT_EMAIL && !body)
 894                 buf[offset++] = '\n';
 895         buf[offset] = '\0';
 896
 897         free(reencoded);
 898         return offset;
 899 }
 900
 901 struct commit *pop_commit(struct commit_list **stack)
 902 {
 903         struct commit_list *top = *stack;
 904         struct commit *item = top ? top->item : NULL;
 905
 906         if (top) {
 907                 *stack = top->next;
 908                 free(top);
 909         }
 910         return item;
 911 }
 912
 913 int count_parents(struct commit * commit)
 914 {
 915         int count;
 916         struct commit_list * parents = commit->parents;
 917         for (count = 0; parents; parents = parents->next,count++)
 918                 ;
 919         return count;
 920 }
 921
 922 void topo_sort_default_setter(struct commit *c, void *data)
 923 {
 924         c->util = data;
 925 }
 926
 927 void *topo_sort_default_getter(struct commit *c)
 928 {
 929         return c->util;
 930 }
 931
 932 /*
 933  * Performs an in-place topological sort on the list supplied.
 934  */
 935 void sort_in_topological_order(struct commit_list ** list, int lifo)
 936 {
 937         sort_in_topological_order_fn(list, lifo, topo_sort_default_setter,
 938                                      topo_sort_default_getter);
 939 }
 940
 941 void sort_in_topological_order_fn(struct commit_list ** list, int lifo,
 942                                   topo_sort_set_fn_t setter,
 943                                   topo_sort_get_fn_t getter)
 944 {
 945         struct commit_list * next = *list;
 946         struct commit_list * work = NULL, **insert;
 947         struct commit_list ** pptr = list;
 948         struct sort_node * nodes;
 949         struct sort_node * next_nodes;
 950         int count = 0;
 951
 952         /* determine the size of the list */
 953         while (next) {
 954                 next = next->next;
 955                 count++;
 956         }
 957
 958         if (!count)
 959                 return;
 960         /* allocate an array to help sort the list */
 961         nodes = xcalloc(count, sizeof(*nodes));
 962         /* link the list to the array */
 963         next_nodes = nodes;
 964         next=*list;
 965         while (next) {
 966                 next_nodes->list_item = next;
 967                 setter(next->item, next_nodes);
 968                 next_nodes++;
 969                 next = next->next;
 970         }
 971         /* update the indegree */
 972         next=*list;
 973         while (next) {
 974                 struct commit_list * parents = next->item->parents;
 975                 while (parents) {
 976                         struct commit * parent=parents->item;
 977                         struct sort_node * pn = (struct sort_node *) getter(parent);
 978
 979                         if (pn)
 980                                 pn->indegree++;
 981                         parents=parents->next;
 982                 }
 983                 next=next->next;
 984         }
 985         /*
 986          * find the tips
 987          *
 988          * tips are nodes not reachable from any other node in the list
 989          *
 990          * the tips serve as a starting set for the work queue.
 991          */
 992         next=*list;
 993         insert = &work;
 994         while (next) {
 995                 struct sort_node * node = (struct sort_node *) getter(next->item);
 996
 997                 if (node->indegree == 0) {
 998                         insert = &commit_list_insert(next->item, insert)->next;
 999                 }
1000                 next=next->next;
1001         }
1002
1003         /* process the list in topological order */
1004         if (!lifo)
1005                 sort_by_date(&work);
1006         while (work) {
1007                 struct commit * work_item = pop_commit(&work);
1008                 struct sort_node * work_node = (struct sort_node *) getter(work_item);
1009                 struct commit_list * parents = work_item->parents;
1010
1011                 while (parents) {
1012                         struct commit * parent=parents->item;
1013                         struct sort_node * pn = (struct sort_node *) getter(parent);
1014
1015                         if (pn) {
1016                                 /*
1017                                  * parents are only enqueued for emission
1018                                  * when all their children have been emitted thereby
1019                                  * guaranteeing topological order.
1020                                  */
1021                                 pn->indegree--;
1022                                 if (!pn->indegree) {
1023                                         if (!lifo)
1024                                                 insert_by_date(parent, &work);
1025                                         else
1026                                                 commit_list_insert(parent, &work);
1027                                 }
1028                         }
1029                         parents=parents->next;
1030                 }
1031                 /*
1032                  * work_item is a commit all of whose children
1033                  * have already been emitted. we can emit it now.
1034                  */
1035                 *pptr = work_node->list_item;
1036                 pptr = &(*pptr)->next;
1037                 *pptr = NULL;
1038                 setter(work_item, NULL);
1039         }
1040         free(nodes);
1041 }
1042
1043 /* merge-base stuff */
1044
1045 /* bits #0..15 in revision.h */
1046 #define PARENT1         (1u<<16)
1047 #define PARENT2         (1u<<17)
1048 #define STALE           (1u<<18)
1049 #define RESULT          (1u<<19)
1050
1051 static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
1052
1053 static struct commit *interesting(struct commit_list *list)
1054 {
1055         while (list) {
1056                 struct commit *commit = list->item;
1057                 list = list->next;
1058                 if (commit->object.flags & STALE)
1059                         continue;
1060                 return commit;
1061         }
1062         return NULL;
1063 }
1064
1065 static struct commit_list *merge_bases(struct commit *one, struct commit *two)
1066 {
1067         struct commit_list *list = NULL;
1068         struct commit_list *result = NULL;
1069
1070         if (one == two)
1071                 /* We do not mark this even with RESULT so we do not
1072                  * have to clean it up.
1073                  */
1074                 return commit_list_insert(one, &result);
1075
1076         parse_commit(one);
1077         parse_commit(two);
1078
1079         one->object.flags |= PARENT1;
1080         two->object.flags |= PARENT2;
1081         insert_by_date(one, &list);
1082         insert_by_date(two, &list);
1083
1084         while (interesting(list)) {
1085                 struct commit *commit;
1086                 struct commit_list *parents;
1087                 struct commit_list *n;
1088                 int flags;
1089
1090                 commit = list->item;
1091                 n = list->next;
1092                 free(list);
1093                 list = n;
1094
1095                 flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
1096                 if (flags == (PARENT1 | PARENT2)) {
1097                         if (!(commit->object.flags & RESULT)) {
1098                                 commit->object.flags |= RESULT;
1099                                 insert_by_date(commit, &result);
1100                         }
1101                         /* Mark parents of a found merge stale */
1102                         flags |= STALE;
1103                 }
1104                 parents = commit->parents;
1105                 while (parents) {
1106                         struct commit *p = parents->item;
1107                         parents = parents->next;
1108                         if ((p->object.flags & flags) == flags)
1109                                 continue;
1110                         parse_commit(p);
1111                         p->object.flags |= flags;
1112                         insert_by_date(p, &list);
1113                 }
1114         }
1115
1116         /* Clean up the result to remove stale ones */
1117         free_commit_list(list);
1118         list = result; result = NULL;
1119         while (list) {
1120                 struct commit_list *n = list->next;
1121                 if (!(list->item->object.flags & STALE))
1122                         insert_by_date(list->item, &result);
1123                 free(list);
1124                 list = n;
1125         }
1126         return result;
1127 }
1128
1129 struct commit_list *get_merge_bases(struct commit *one,
1130                                     struct commit *two,
1131                                     int cleanup)
1132 {
1133         struct commit_list *list;
1134         struct commit **rslt;
1135         struct commit_list *result;
1136         int cnt, i, j;
1137
1138         result = merge_bases(one, two);
1139         if (one == two)
1140                 return result;
1141         if (!result || !result->next) {
1142                 if (cleanup) {
1143                         clear_commit_marks(one, all_flags);
1144                         clear_commit_marks(two, all_flags);
1145                 }
1146                 return result;
1147         }
1148
1149         /* There are more than one */
1150         cnt = 0;
1151         list = result;
1152         while (list) {
1153                 list = list->next;
1154                 cnt++;
1155         }
1156         rslt = xcalloc(cnt, sizeof(*rslt));
1157         for (list = result, i = 0; list; list = list->next)
1158                 rslt[i++] = list->item;
1159         free_commit_list(result);
1160
1161         clear_commit_marks(one, all_flags);
1162         clear_commit_marks(two, all_flags);
1163         for (i = 0; i < cnt - 1; i++) {
1164                 for (j = i+1; j < cnt; j++) {
1165                         if (!rslt[i] || !rslt[j])
1166                                 continue;
1167                         result = merge_bases(rslt[i], rslt[j]);
1168                         clear_commit_marks(rslt[i], all_flags);
1169                         clear_commit_marks(rslt[j], all_flags);
1170                         for (list = result; list; list = list->next) {
1171                                 if (rslt[i] == list->item)
1172                                         rslt[i] = NULL;
1173                                 if (rslt[j] == list->item)
1174                                         rslt[j] = NULL;
1175                         }
1176                 }
1177         }
1178
1179         /* Surviving ones in rslt[] are the independent results */
1180         result = NULL;
1181         for (i = 0; i < cnt; i++) {
1182                 if (rslt[i])
1183                         insert_by_date(rslt[i], &result);
1184         }
1185         free(rslt);
1186         return result;
1187 }
1188
1189 int in_merge_bases(struct commit *rev1, struct commit *rev2)
1190 {
1191         struct commit_list *bases, *b;
1192         int ret = 0;
1193
1194         bases = get_merge_bases(rev1, rev2, 1);
1195         for (b = bases; b; b = b->next) {
1196                 if (!hashcmp(rev1->object.sha1, b->item->object.sha1)) {
1197                         ret = 1;
1198                         break;
1199                 }
1200         }
1201
1202         free_commit_list(bases);
1203         return ret;
1204 }