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