commit.c

   1 #include <ctype.h>
   2 #include "tag.h"
   3 #include "commit.h"
   4 #include "cache.h"
   5
   6 struct sort_node
   7 {
   8         /*
   9          * the number of children of the associated commit
  10          * that also occur in the list being sorted.
  11          */
  12         unsigned int indegree;
  13
  14         /*
  15          * reference to original list item that we will re-use
  16          * on output.
  17          */
  18         struct commit_list * list_item;
  19
  20 };
  21
  22 const char *commit_type = "commit";
  23
  24 enum cmit_fmt get_commit_format(const char *arg)
  25 {
  26         if (!*arg)
  27                 return CMIT_FMT_DEFAULT;
  28         if (!strcmp(arg, "=raw"))
  29                 return CMIT_FMT_RAW;
  30         if (!strcmp(arg, "=medium"))
  31                 return CMIT_FMT_MEDIUM;
  32         if (!strcmp(arg, "=short"))
  33                 return CMIT_FMT_SHORT;
  34         if (!strcmp(arg, "=full"))
  35                 return CMIT_FMT_FULL;
  36         die("invalid --pretty format");
  37 }
  38
  39 static struct commit *check_commit(struct object *obj, const unsigned char *sha1)
  40 {
  41         if (obj->type != commit_type) {
  42                 error("Object %s is a %s, not a commit",
  43                       sha1_to_hex(sha1), obj->type);
  44                 return NULL;
  45         }
  46         return (struct commit *) obj;
  47 }
  48
  49 struct commit *lookup_commit_reference(const unsigned char *sha1)
  50 {
  51         struct object *obj = parse_object(sha1);
  52
  53         if (!obj)
  54                 return NULL;
  55         while (obj->type == tag_type)
  56                 obj = parse_object(((struct tag *)obj)->tagged->sha1);
  57
  58         return check_commit(obj, sha1);
  59 }
  60
  61 struct commit *lookup_commit(const unsigned char *sha1)
  62 {
  63         struct object *obj = lookup_object(sha1);
  64         if (!obj) {
  65                 struct commit *ret = xmalloc(sizeof(struct commit));
  66                 memset(ret, 0, sizeof(struct commit));
  67                 created_object(sha1, &ret->object);
  68                 ret->object.type = commit_type;
  69                 return ret;
  70         }
  71         if (!obj->type)
  72                 obj->type = commit_type;
  73         return check_commit(obj, sha1);
  74 }
  75
  76 static unsigned long parse_commit_date(const char *buf)
  77 {
  78         unsigned long date;
  79
  80         if (memcmp(buf, "author", 6))
  81                 return 0;
  82         while (*buf++ != '\n')
  83                 /* nada */;
  84         if (memcmp(buf, "committer", 9))
  85                 return 0;
  86         while (*buf++ != '>')
  87                 /* nada */;
  88         date = strtoul(buf, NULL, 10);
  89         if (date == ULONG_MAX)
  90                 date = 0;
  91         return date;
  92 }
  93
  94 static struct commit_graft {
  95         unsigned char sha1[20];
  96         int nr_parent;
  97         unsigned char parent[0][20]; /* more */
  98 } **commit_graft;
  99 static int commit_graft_alloc, commit_graft_nr;
 100
 101 static int commit_graft_pos(const unsigned char *sha1)
 102 {
 103         int lo, hi;
 104         lo = 0;
 105         hi = commit_graft_nr;
 106         while (lo < hi) {
 107                 int mi = (lo + hi) / 2;
 108                 struct commit_graft *graft = commit_graft[mi];
 109                 int cmp = memcmp(sha1, graft->sha1, 20);
 110                 if (!cmp)
 111                         return mi;
 112                 if (cmp < 0)
 113                         hi = mi;
 114                 else
 115                         lo = mi + 1;
 116         }
 117         return -lo - 1;
 118 }
 119
 120 static void prepare_commit_graft(void)
 121 {
 122         char *graft_file = get_graft_file();
 123         FILE *fp = fopen(graft_file, "r");
 124         char buf[1024];
 125         if (!fp) {
 126                 commit_graft = (struct commit_graft **) "hack";
 127                 return;
 128         }
 129         while (fgets(buf, sizeof(buf), fp)) {
 130                 /* The format is just "Commit Parent1 Parent2 ...\n" */
 131                 int len = strlen(buf);
 132                 int i;
 133                 struct commit_graft *graft = NULL;
 134
 135                 if (buf[len-1] == '\n')
 136                         buf[--len] = 0;
 137                 if (buf[0] == '#')
 138                         continue;
 139                 if ((len + 1) % 41) {
 140                 bad_graft_data:
 141                         error("bad graft data: %s", buf);
 142                         free(graft);
 143                         continue;
 144                 }
 145                 i = (len + 1) / 41 - 1;
 146                 graft = xmalloc(sizeof(*graft) + 20 * i);
 147                 graft->nr_parent = i;
 148                 if (get_sha1_hex(buf, graft->sha1))
 149                         goto bad_graft_data;
 150                 for (i = 40; i < len; i += 41) {
 151                         if (buf[i] != ' ')
 152                                 goto bad_graft_data;
 153                         if (get_sha1_hex(buf + i + 1, graft->parent[i/41]))
 154                                 goto bad_graft_data;
 155                 }
 156                 i = commit_graft_pos(graft->sha1);
 157                 if (0 <= i) {
 158                         error("duplicate graft data: %s", buf);
 159                         free(graft);
 160                         continue;
 161                 }
 162                 i = -i - 1;
 163                 if (commit_graft_alloc <= ++commit_graft_nr) {
 164                         commit_graft_alloc = alloc_nr(commit_graft_alloc);
 165                         commit_graft = xrealloc(commit_graft,
 166                                                 sizeof(*commit_graft) *
 167                                                 commit_graft_alloc);
 168                 }
 169                 if (i < commit_graft_nr)
 170                         memmove(commit_graft + i + 1,
 171                                 commit_graft + i,
 172                                 (commit_graft_nr - i - 1) *
 173                                 sizeof(*commit_graft));
 174                 commit_graft[i] = graft;
 175         }
 176         fclose(fp);
 177 }
 178
 179 static struct commit_graft *lookup_commit_graft(const unsigned char *sha1)
 180 {
 181         int pos;
 182         if (!commit_graft)
 183                 prepare_commit_graft();
 184         pos = commit_graft_pos(sha1);
 185         if (pos < 0)
 186                 return NULL;
 187         return commit_graft[pos];
 188 }
 189
 190 int parse_commit_buffer(struct commit *item, void *buffer, unsigned long size)
 191 {
 192         char *bufptr = buffer;
 193         unsigned char parent[20];
 194         struct commit_list **pptr;
 195         struct commit_graft *graft;
 196
 197         if (item->object.parsed)
 198                 return 0;
 199         item->object.parsed = 1;
 200         if (memcmp(bufptr, "tree ", 5))
 201                 return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
 202         if (get_sha1_hex(bufptr + 5, parent) < 0)
 203                 return error("bad tree pointer in commit %s\n", sha1_to_hex(item->object.sha1));
 204         item->tree = lookup_tree(parent);
 205         if (item->tree)
 206                 add_ref(&item->object, &item->tree->object);
 207         bufptr += 46; /* "tree " + "hex sha1" + "\n" */
 208         pptr = &item->parents;
 209
 210         graft = lookup_commit_graft(item->object.sha1);
 211         while (!memcmp(bufptr, "parent ", 7)) {
 212                 struct commit *new_parent;
 213
 214                 if (get_sha1_hex(bufptr + 7, parent) || bufptr[47] != '\n')
 215                         return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
 216                 bufptr += 48;
 217                 if (graft)
 218                         continue;
 219                 new_parent = lookup_commit(parent);
 220                 if (new_parent) {
 221                         pptr = &commit_list_insert(new_parent, pptr)->next;
 222                         add_ref(&item->object, &new_parent->object);
 223                 }
 224         }
 225         if (graft) {
 226                 int i;
 227                 struct commit *new_parent;
 228                 for (i = 0; i < graft->nr_parent; i++) {
 229                         new_parent = lookup_commit(graft->parent[i]);
 230                         if (!new_parent)
 231                                 continue;
 232                         pptr = &commit_list_insert(new_parent, pptr)->next;
 233                         add_ref(&item->object, &new_parent->object);
 234                 }
 235         }
 236         item->date = parse_commit_date(bufptr);
 237         return 0;
 238 }
 239
 240 int parse_commit(struct commit *item)
 241 {
 242         char type[20];
 243         void *buffer;
 244         unsigned long size;
 245         int ret;
 246
 247         if (item->object.parsed)
 248                 return 0;
 249         buffer = read_sha1_file(item->object.sha1, type, &size);
 250         if (!buffer)
 251                 return error("Could not read %s",
 252                              sha1_to_hex(item->object.sha1));
 253         if (strcmp(type, commit_type)) {
 254                 free(buffer);
 255                 return error("Object %s not a commit",
 256                              sha1_to_hex(item->object.sha1));
 257         }
 258         ret = parse_commit_buffer(item, buffer, size);
 259         if (!ret) {
 260                 item->buffer = buffer;
 261                 return 0;
 262         }
 263         free(buffer);
 264         return ret;
 265 }
 266
 267 struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
 268 {
 269         struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
 270         new_list->item = item;
 271         new_list->next = *list_p;
 272         *list_p = new_list;
 273         return new_list;
 274 }
 275
 276 void free_commit_list(struct commit_list *list)
 277 {
 278         while (list) {
 279                 struct commit_list *temp = list;
 280                 list = temp->next;
 281                 free(temp);
 282         }
 283 }
 284
 285 struct commit_list * insert_by_date(struct commit *item, struct commit_list **list)
 286 {
 287         struct commit_list **pp = list;
 288         struct commit_list *p;
 289         while ((p = *pp) != NULL) {
 290                 if (p->item->date < item->date) {
 291                         break;
 292                 }
 293                 pp = &p->next;
 294         }
 295         return commit_list_insert(item, pp);
 296 }
 297
 298
 299 void sort_by_date(struct commit_list **list)
 300 {
 301         struct commit_list *ret = NULL;
 302         while (*list) {
 303                 insert_by_date((*list)->item, &ret);
 304                 *list = (*list)->next;
 305         }
 306         *list = ret;
 307 }
 308
 309 struct commit *pop_most_recent_commit(struct commit_list **list,
 310                                       unsigned int mark)
 311 {
 312         struct commit *ret = (*list)->item;
 313         struct commit_list *parents = ret->parents;
 314         struct commit_list *old = *list;
 315
 316         *list = (*list)->next;
 317         free(old);
 318
 319         while (parents) {
 320                 struct commit *commit = parents->item;
 321                 parse_commit(commit);
 322                 if (!(commit->object.flags & mark)) {
 323                         commit->object.flags |= mark;
 324                         insert_by_date(commit, list);
 325                 }
 326                 parents = parents->next;
 327         }
 328         return ret;
 329 }
 330
 331 /*
 332  * Generic support for pretty-printing the header
 333  */
 334 static int get_one_line(const char *msg, unsigned long len)
 335 {
 336         int ret = 0;
 337
 338         while (len--) {
 339                 char c = *msg++;
 340                 ret++;
 341                 if (c == '\n')
 342                         break;
 343                 if (!c)
 344                         return 0;
 345         }
 346         return ret;
 347 }
 348
 349 static int add_user_info(const char *what, enum cmit_fmt fmt, char *buf, const char *line)
 350 {
 351         char *date;
 352         unsigned int namelen;
 353         unsigned long time;
 354         int tz, ret;
 355
 356         date = strchr(line, '>');
 357         if (!date)
 358                 return 0;
 359         namelen = ++date - line;
 360         time = strtoul(date, &date, 10);
 361         tz = strtol(date, NULL, 10);
 362
 363         ret = sprintf(buf, "%s: %.*s\n", what, namelen, line);
 364         if (fmt == CMIT_FMT_MEDIUM)
 365                 ret += sprintf(buf + ret, "Date:   %s\n", show_date(time, tz));
 366         return ret;
 367 }
 368
 369 static int is_empty_line(const char *line, int len)
 370 {
 371         while (len && isspace(line[len-1]))
 372                 len--;
 373         return !len;
 374 }
 375
 376 static int add_parent_info(enum cmit_fmt fmt, char *buf, const char *line, int parents)
 377 {
 378         int offset = 0;
 379         switch (parents) {
 380         case 1:
 381                 break;
 382         case 2:
 383                 /* Go back to the previous line: 40 characters of previous parent, and one '\n' */
 384                 offset = sprintf(buf, "Merge: %.40s\n", line-41);
 385                 /* Fallthrough */
 386         default:
 387                 /* Replace the previous '\n' with a space */
 388                 buf[offset-1] = ' ';
 389                 offset += sprintf(buf + offset, "%.40s\n", line+7);
 390         }
 391         return offset;
 392 }
 393
 394 unsigned long pretty_print_commit(enum cmit_fmt fmt, const char *msg, unsigned long len, char *buf, unsigned long space)
 395 {
 396         int hdr = 1, body = 0;
 397         unsigned long offset = 0;
 398         int parents = 0;
 399
 400         for (;;) {
 401                 const char *line = msg;
 402                 int linelen = get_one_line(msg, len);
 403
 404                 if (!linelen)
 405                         break;
 406
 407                 /*
 408                  * We want some slop for indentation and a possible
 409                  * final "...". Thus the "+ 20".
 410                  */
 411                 if (offset + linelen + 20 > space) {
 412                         memcpy(buf + offset, "    ...\n", 8);
 413                         offset += 8;
 414                         break;
 415                 }
 416
 417                 msg += linelen;
 418                 len -= linelen;
 419                 if (hdr) {
 420                         if (linelen == 1) {
 421                                 hdr = 0;
 422                                 buf[offset++] = '\n';
 423                                 continue;
 424                         }
 425                         if (fmt == CMIT_FMT_RAW) {
 426                                 memcpy(buf + offset, line, linelen);
 427                                 offset += linelen;
 428                                 continue;
 429                         }
 430                         if (!memcmp(line, "parent ", 7)) {
 431                                 if (linelen != 48)
 432                                         die("bad parent line in commit");
 433                                 offset += add_parent_info(fmt, buf + offset, line, ++parents);
 434                         }
 435                         if (!memcmp(line, "author ", 7))
 436                                 offset += add_user_info("Author", fmt, buf + offset, line + 7);
 437                         if (fmt == CMIT_FMT_FULL) {
 438                                 if (!memcmp(line, "committer ", 10))
 439                                         offset += add_user_info("Commit", fmt, buf + offset, line + 10);
 440                         }
 441                         continue;
 442                 }
 443
 444                 if (is_empty_line(line, linelen)) {
 445                         if (!body)
 446                                 continue;
 447                         if (fmt == CMIT_FMT_SHORT)
 448                                 break;
 449                 } else {
 450                         body = 1;
 451                 }
 452                 memset(buf + offset, ' ', 4);
 453                 memcpy(buf + offset + 4, line, linelen);
 454                 offset += linelen + 4;
 455         }
 456         /* Make sure there is an EOLN */
 457         if (buf[offset - 1] != '\n')
 458                 buf[offset++] = '\n';
 459         buf[offset] = '\0';
 460         return offset;
 461 }
 462
 463 struct commit *pop_commit(struct commit_list **stack)
 464 {
 465         struct commit_list *top = *stack;
 466         struct commit *item = top ? top->item : NULL;
 467
 468         if (top) {
 469                 *stack = top->next;
 470                 free(top);
 471         }
 472         return item;
 473 }
 474
 475 int count_parents(struct commit * commit)
 476 {
 477         int count = 0;
 478         struct commit_list * parents = commit->parents;
 479         for (count=0;parents; parents=parents->next,count++)
 480           ;
 481         return count;
 482 }
 483
 484 /*
 485  * Performs an in-place topological sort on the list supplied.
 486  */
 487 void sort_in_topological_order(struct commit_list ** list)
 488 {
 489         struct commit_list * next = *list;
 490         struct commit_list * work = NULL;
 491         struct commit_list ** pptr = list;
 492         struct sort_node * nodes;
 493         struct sort_node * next_nodes;
 494         int count = 0;
 495
 496         /* determine the size of the list */
 497         while (next) {
 498                 next = next->next;
 499                 count++;
 500         }
 501         /* allocate an array to help sort the list */
 502         nodes = xcalloc(count, sizeof(*nodes));
 503         /* link the list to the array */
 504         next_nodes = nodes;
 505         next=*list;
 506         while (next) {
 507                 next_nodes->list_item = next;
 508                 next->item->object.util = next_nodes;
 509                 next_nodes++;
 510                 next = next->next;
 511         }
 512         /* update the indegree */
 513         next=*list;
 514         while (next) {
 515                 struct commit_list * parents = next->item->parents;
 516                 while (parents) {
 517                         struct commit * parent=parents->item;
 518                         struct sort_node * pn = (struct sort_node *)parent->object.util;
 519
 520                         if (pn)
 521                                 pn->indegree++;
 522                         parents=parents->next;
 523                 }
 524                 next=next->next;
 525         }
 526         /*
 527          * find the tips
 528          *
 529          * tips are nodes not reachable from any other node in the list
 530          *
 531          * the tips serve as a starting set for the work queue.
 532          */
 533         next=*list;
 534         while (next) {
 535                 struct sort_node * node = (struct sort_node *)next->item->object.util;
 536
 537                 if (node->indegree == 0) {
 538                         commit_list_insert(next->item, &work);
 539                 }
 540                 next=next->next;
 541         }
 542         /* process the list in topological order */
 543         while (work) {
 544                 struct commit * work_item = pop_commit(&work);
 545                 struct sort_node * work_node = (struct sort_node *)work_item->object.util;
 546                 struct commit_list * parents = work_item->parents;
 547
 548                 while (parents) {
 549                         struct commit * parent=parents->item;
 550                         struct sort_node * pn = (struct sort_node *)parent->object.util;
 551
 552                         if (pn) {
 553                                 /*
 554                                  * parents are only enqueued for emission
 555                                  * when all their children have been emitted thereby
 556                                  * guaranteeing topological order.
 557                                  */
 558                                 pn->indegree--;
 559                                 if (!pn->indegree)
 560                                         commit_list_insert(parent, &work);
 561                         }
 562                         parents=parents->next;
 563                 }
 564                 /*
 565                  * work_item is a commit all of whose children
 566                  * have already been emitted. we can emit it now.
 567                  */
 568                 *pptr = work_node->list_item;
 569                 pptr = &(*pptr)->next;
 570                 *pptr = NULL;
 571                 work_item->object.util = NULL;
 572         }
 573         free(nodes);
 574 }