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         if (!strcmp(arg, "=oneline"))
  37                 return CMIT_FMT_ONELINE;
  38         die("invalid --pretty format");
  39 }
  40
  41 static struct commit *check_commit(struct object *obj, const unsigned char *sha1)
  42 {
  43         if (obj->type != commit_type) {
  44                 error("Object %s is a %s, not a commit",
  45                       sha1_to_hex(sha1), obj->type);
  46                 return NULL;
  47         }
  48         return (struct commit *) obj;
  49 }
  50
  51 struct commit *lookup_commit_reference(const unsigned char *sha1)
  52 {
  53         struct object *obj = deref_tag(parse_object(sha1));
  54
  55         if (!obj)
  56                 return NULL;
  57         return check_commit(obj, sha1);
  58 }
  59
  60 struct commit *lookup_commit(const unsigned char *sha1)
  61 {
  62         struct object *obj = lookup_object(sha1);
  63         if (!obj) {
  64                 struct commit *ret = xmalloc(sizeof(struct commit));
  65                 memset(ret, 0, sizeof(struct commit));
  66                 created_object(sha1, &ret->object);
  67                 ret->object.type = commit_type;
  68                 return ret;
  69         }
  70         if (!obj->type)
  71                 obj->type = commit_type;
  72         return check_commit(obj, sha1);
  73 }
  74
  75 static unsigned long parse_commit_date(const char *buf)
  76 {
  77         unsigned long date;
  78
  79         if (memcmp(buf, "author", 6))
  80                 return 0;
  81         while (*buf++ != '\n')
  82                 /* nada */;
  83         if (memcmp(buf, "committer", 9))
  84                 return 0;
  85         while (*buf++ != '>')
  86                 /* nada */;
  87         date = strtoul(buf, NULL, 10);
  88         if (date == ULONG_MAX)
  89                 date = 0;
  90         return date;
  91 }
  92
  93 static struct commit_graft {
  94         unsigned char sha1[20];
  95         int nr_parent;
  96         unsigned char parent[0][20]; /* more */
  97 } **commit_graft;
  98 static int commit_graft_alloc, commit_graft_nr;
  99
 100 static int commit_graft_pos(const unsigned char *sha1)
 101 {
 102         int lo, hi;
 103         lo = 0;
 104         hi = commit_graft_nr;
 105         while (lo < hi) {
 106                 int mi = (lo + hi) / 2;
 107                 struct commit_graft *graft = commit_graft[mi];
 108                 int cmp = memcmp(sha1, graft->sha1, 20);
 109                 if (!cmp)
 110                         return mi;
 111                 if (cmp < 0)
 112                         hi = mi;
 113                 else
 114                         lo = mi + 1;
 115         }
 116         return -lo - 1;
 117 }
 118
 119 static void prepare_commit_graft(void)
 120 {
 121         char *graft_file = get_graft_file();
 122         FILE *fp = fopen(graft_file, "r");
 123         char buf[1024];
 124         if (!fp) {
 125                 commit_graft = (struct commit_graft **) "hack";
 126                 return;
 127         }
 128         while (fgets(buf, sizeof(buf), fp)) {
 129                 /* The format is just "Commit Parent1 Parent2 ...\n" */
 130                 int len = strlen(buf);
 131                 int i;
 132                 struct commit_graft *graft = NULL;
 133
 134                 if (buf[len-1] == '\n')
 135                         buf[--len] = 0;
 136                 if (buf[0] == '#')
 137                         continue;
 138                 if ((len + 1) % 41) {
 139                 bad_graft_data:
 140                         error("bad graft data: %s", buf);
 141                         free(graft);
 142                         continue;
 143                 }
 144                 i = (len + 1) / 41 - 1;
 145                 graft = xmalloc(sizeof(*graft) + 20 * i);
 146                 graft->nr_parent = i;
 147                 if (get_sha1_hex(buf, graft->sha1))
 148                         goto bad_graft_data;
 149                 for (i = 40; i < len; i += 41) {
 150                         if (buf[i] != ' ')
 151                                 goto bad_graft_data;
 152                         if (get_sha1_hex(buf + i + 1, graft->parent[i/41]))
 153                                 goto bad_graft_data;
 154                 }
 155                 i = commit_graft_pos(graft->sha1);
 156                 if (0 <= i) {
 157                         error("duplicate graft data: %s", buf);
 158                         free(graft);
 159                         continue;
 160                 }
 161                 i = -i - 1;
 162                 if (commit_graft_alloc <= ++commit_graft_nr) {
 163                         commit_graft_alloc = alloc_nr(commit_graft_alloc);
 164                         commit_graft = xrealloc(commit_graft,
 165                                                 sizeof(*commit_graft) *
 166                                                 commit_graft_alloc);
 167                 }
 168                 if (i < commit_graft_nr)
 169                         memmove(commit_graft + i + 1,
 170                                 commit_graft + i,
 171                                 (commit_graft_nr - i - 1) *
 172                                 sizeof(*commit_graft));
 173                 commit_graft[i] = graft;
 174         }
 175         fclose(fp);
 176 }
 177
 178 static struct commit_graft *lookup_commit_graft(const unsigned char *sha1)
 179 {
 180         int pos;
 181         if (!commit_graft)
 182                 prepare_commit_graft();
 183         pos = commit_graft_pos(sha1);
 184         if (pos < 0)
 185                 return NULL;
 186         return commit_graft[pos];
 187 }
 188
 189 int parse_commit_buffer(struct commit *item, void *buffer, unsigned long size)
 190 {
 191         char *bufptr = buffer;
 192         unsigned char parent[20];
 193         struct commit_list **pptr;
 194         struct commit_graft *graft;
 195
 196         if (item->object.parsed)
 197                 return 0;
 198         item->object.parsed = 1;
 199         if (memcmp(bufptr, "tree ", 5))
 200                 return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
 201         if (get_sha1_hex(bufptr + 5, parent) < 0)
 202                 return error("bad tree pointer in commit %s\n", sha1_to_hex(item->object.sha1));
 203         item->tree = lookup_tree(parent);
 204         if (item->tree)
 205                 add_ref(&item->object, &item->tree->object);
 206         bufptr += 46; /* "tree " + "hex sha1" + "\n" */
 207         pptr = &item->parents;
 208
 209         graft = lookup_commit_graft(item->object.sha1);
 210         while (!memcmp(bufptr, "parent ", 7)) {
 211                 struct commit *new_parent;
 212
 213                 if (get_sha1_hex(bufptr + 7, parent) || bufptr[47] != '\n')
 214                         return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
 215                 bufptr += 48;
 216                 if (graft)
 217                         continue;
 218                 new_parent = lookup_commit(parent);
 219                 if (new_parent) {
 220                         pptr = &commit_list_insert(new_parent, pptr)->next;
 221                         add_ref(&item->object, &new_parent->object);
 222                 }
 223         }
 224         if (graft) {
 225                 int i;
 226                 struct commit *new_parent;
 227                 for (i = 0; i < graft->nr_parent; i++) {
 228                         new_parent = lookup_commit(graft->parent[i]);
 229                         if (!new_parent)
 230                                 continue;
 231                         pptr = &commit_list_insert(new_parent, pptr)->next;
 232                         add_ref(&item->object, &new_parent->object);
 233                 }
 234         }
 235         item->date = parse_commit_date(bufptr);
 236         return 0;
 237 }
 238
 239 int parse_commit(struct commit *item)
 240 {
 241         char type[20];
 242         void *buffer;
 243         unsigned long size;
 244         int ret;
 245
 246         if (item->object.parsed)
 247                 return 0;
 248         buffer = read_sha1_file(item->object.sha1, type, &size);
 249         if (!buffer)
 250                 return error("Could not read %s",
 251                              sha1_to_hex(item->object.sha1));
 252         if (strcmp(type, commit_type)) {
 253                 free(buffer);
 254                 return error("Object %s not a commit",
 255                              sha1_to_hex(item->object.sha1));
 256         }
 257         ret = parse_commit_buffer(item, buffer, size);
 258         if (!ret) {
 259                 item->buffer = buffer;
 260                 return 0;
 261         }
 262         free(buffer);
 263         return ret;
 264 }
 265
 266 struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
 267 {
 268         struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
 269         new_list->item = item;
 270         new_list->next = *list_p;
 271         *list_p = new_list;
 272         return new_list;
 273 }
 274
 275 void free_commit_list(struct commit_list *list)
 276 {
 277         while (list) {
 278                 struct commit_list *temp = list;
 279                 list = temp->next;
 280                 free(temp);
 281         }
 282 }
 283
 284 struct commit_list * insert_by_date(struct commit *item, struct commit_list **list)
 285 {
 286         struct commit_list **pp = list;
 287         struct commit_list *p;
 288         while ((p = *pp) != NULL) {
 289                 if (p->item->date < item->date) {
 290                         break;
 291                 }
 292                 pp = &p->next;
 293         }
 294         return commit_list_insert(item, pp);
 295 }
 296
 297
 298 void sort_by_date(struct commit_list **list)
 299 {
 300         struct commit_list *ret = NULL;
 301         while (*list) {
 302                 insert_by_date((*list)->item, &ret);
 303                 *list = (*list)->next;
 304         }
 305         *list = ret;
 306 }
 307
 308 struct commit *pop_most_recent_commit(struct commit_list **list,
 309                                       unsigned int mark)
 310 {
 311         struct commit *ret = (*list)->item;
 312         struct commit_list *parents = ret->parents;
 313         struct commit_list *old = *list;
 314
 315         *list = (*list)->next;
 316         free(old);
 317
 318         while (parents) {
 319                 struct commit *commit = parents->item;
 320                 parse_commit(commit);
 321                 if (!(commit->object.flags & mark)) {
 322                         commit->object.flags |= mark;
 323                         insert_by_date(commit, list);
 324                 }
 325                 parents = parents->next;
 326         }
 327         return ret;
 328 }
 329
 330 /*
 331  * Generic support for pretty-printing the header
 332  */
 333 static int get_one_line(const char *msg, unsigned long len)
 334 {
 335         int ret = 0;
 336
 337         while (len--) {
 338                 char c = *msg++;
 339                 ret++;
 340                 if (c == '\n')
 341                         break;
 342                 if (!c)
 343                         return 0;
 344         }
 345         return ret;
 346 }
 347
 348 static int add_user_info(const char *what, enum cmit_fmt fmt, char *buf, const char *line)
 349 {
 350         char *date;
 351         unsigned int namelen;
 352         unsigned long time;
 353         int tz, ret;
 354
 355         if (fmt == CMIT_FMT_ONELINE)
 356                 return 0;
 357         date = strchr(line, '>');
 358         if (!date)
 359                 return 0;
 360         namelen = ++date - line;
 361         time = strtoul(date, &date, 10);
 362         tz = strtol(date, NULL, 10);
 363
 364         ret = sprintf(buf, "%s: %.*s\n", what, namelen, line);
 365         if (fmt == CMIT_FMT_MEDIUM)
 366                 ret += sprintf(buf + ret, "Date:   %s\n", show_date(time, tz));
 367         return ret;
 368 }
 369
 370 static int is_empty_line(const char *line, int len)
 371 {
 372         while (len && isspace(line[len-1]))
 373                 len--;
 374         return !len;
 375 }
 376
 377 static int add_parent_info(enum cmit_fmt fmt, char *buf, const char *line, int parents)
 378 {
 379         int offset = 0;
 380
 381         if (fmt == CMIT_FMT_ONELINE)
 382                 return offset;
 383         switch (parents) {
 384         case 1:
 385                 break;
 386         case 2:
 387                 /* Go back to the previous line: 40 characters of previous parent, and one '\n' */
 388                 offset = sprintf(buf, "Merge: %.40s\n", line-41);
 389                 /* Fallthrough */
 390         default:
 391                 /* Replace the previous '\n' with a space */
 392                 buf[offset-1] = ' ';
 393                 offset += sprintf(buf + offset, "%.40s\n", line+7);
 394         }
 395         return offset;
 396 }
 397
 398 unsigned long pretty_print_commit(enum cmit_fmt fmt, const char *msg, unsigned long len, char *buf, unsigned long space)
 399 {
 400         int hdr = 1, body = 0;
 401         unsigned long offset = 0;
 402         int parents = 0;
 403         int indent = (fmt == CMIT_FMT_ONELINE) ? 0 : 4;
 404
 405         for (;;) {
 406                 const char *line = msg;
 407                 int linelen = get_one_line(msg, len);
 408
 409                 if (!linelen)
 410                         break;
 411
 412                 /*
 413                  * We want some slop for indentation and a possible
 414                  * final "...". Thus the "+ 20".
 415                  */
 416                 if (offset + linelen + 20 > space) {
 417                         memcpy(buf + offset, "    ...\n", 8);
 418                         offset += 8;
 419                         break;
 420                 }
 421
 422                 msg += linelen;
 423                 len -= linelen;
 424                 if (hdr) {
 425                         if (linelen == 1) {
 426                                 hdr = 0;
 427                                 if (fmt != CMIT_FMT_ONELINE)
 428                                         buf[offset++] = '\n';
 429                                 continue;
 430                         }
 431                         if (fmt == CMIT_FMT_RAW) {
 432                                 memcpy(buf + offset, line, linelen);
 433                                 offset += linelen;
 434                                 continue;
 435                         }
 436                         if (!memcmp(line, "parent ", 7)) {
 437                                 if (linelen != 48)
 438                                         die("bad parent line in commit");
 439                                 offset += add_parent_info(fmt, buf + offset, line, ++parents);
 440                         }
 441                         if (!memcmp(line, "author ", 7))
 442                                 offset += add_user_info("Author", fmt, buf + offset, line + 7);
 443                         if (fmt == CMIT_FMT_FULL) {
 444                                 if (!memcmp(line, "committer ", 10))
 445                                         offset += add_user_info("Commit", fmt, buf + offset, line + 10);
 446                         }
 447                         continue;
 448                 }
 449
 450                 if (is_empty_line(line, linelen)) {
 451                         if (!body)
 452                                 continue;
 453                         if (fmt == CMIT_FMT_SHORT)
 454                                 break;
 455                 } else {
 456                         body = 1;
 457                 }
 458
 459                 memset(buf + offset, ' ', indent);
 460                 memcpy(buf + offset + indent, line, linelen);
 461                 offset += linelen + indent;
 462                 if (fmt == CMIT_FMT_ONELINE)
 463                         break;
 464         }
 465         if (fmt == CMIT_FMT_ONELINE) {
 466                 /* We do not want the terminating newline */
 467                 if (buf[offset - 1] == '\n')
 468                         offset--;
 469         }
 470         else {
 471                 /* Make sure there is an EOLN */
 472                 if (buf[offset - 1] != '\n')
 473                         buf[offset++] = '\n';
 474         }
 475         buf[offset] = '\0';
 476         return offset;
 477 }
 478
 479 struct commit *pop_commit(struct commit_list **stack)
 480 {
 481         struct commit_list *top = *stack;
 482         struct commit *item = top ? top->item : NULL;
 483
 484         if (top) {
 485                 *stack = top->next;
 486                 free(top);
 487         }
 488         return item;
 489 }
 490
 491 int count_parents(struct commit * commit)
 492 {
 493         int count = 0;
 494         struct commit_list * parents = commit->parents;
 495         for (count=0;parents; parents=parents->next,count++)
 496           ;
 497         return count;
 498 }
 499
 500 /*
 501  * Performs an in-place topological sort on the list supplied.
 502  */
 503 void sort_in_topological_order(struct commit_list ** list)
 504 {
 505         struct commit_list * next = *list;
 506         struct commit_list * work = NULL;
 507         struct commit_list ** pptr = list;
 508         struct sort_node * nodes;
 509         struct sort_node * next_nodes;
 510         int count = 0;
 511
 512         /* determine the size of the list */
 513         while (next) {
 514                 next = next->next;
 515                 count++;
 516         }
 517         /* allocate an array to help sort the list */
 518         nodes = xcalloc(count, sizeof(*nodes));
 519         /* link the list to the array */
 520         next_nodes = nodes;
 521         next=*list;
 522         while (next) {
 523                 next_nodes->list_item = next;
 524                 next->item->object.util = next_nodes;
 525                 next_nodes++;
 526                 next = next->next;
 527         }
 528         /* update the indegree */
 529         next=*list;
 530         while (next) {
 531                 struct commit_list * parents = next->item->parents;
 532                 while (parents) {
 533                         struct commit * parent=parents->item;
 534                         struct sort_node * pn = (struct sort_node *)parent->object.util;
 535
 536                         if (pn)
 537                                 pn->indegree++;
 538                         parents=parents->next;
 539                 }
 540                 next=next->next;
 541         }
 542         /*
 543          * find the tips
 544          *
 545          * tips are nodes not reachable from any other node in the list
 546          *
 547          * the tips serve as a starting set for the work queue.
 548          */
 549         next=*list;
 550         while (next) {
 551                 struct sort_node * node = (struct sort_node *)next->item->object.util;
 552
 553                 if (node->indegree == 0) {
 554                         commit_list_insert(next->item, &work);
 555                 }
 556                 next=next->next;
 557         }
 558         /* process the list in topological order */
 559         while (work) {
 560                 struct commit * work_item = pop_commit(&work);
 561                 struct sort_node * work_node = (struct sort_node *)work_item->object.util;
 562                 struct commit_list * parents = work_item->parents;
 563
 564                 while (parents) {
 565                         struct commit * parent=parents->item;
 566                         struct sort_node * pn = (struct sort_node *)parent->object.util;
 567
 568                         if (pn) {
 569                                 /*
 570                                  * parents are only enqueued for emission
 571                                  * when all their children have been emitted thereby
 572                                  * guaranteeing topological order.
 573                                  */
 574                                 pn->indegree--;
 575                                 if (!pn->indegree)
 576                                         commit_list_insert(parent, &work);
 577                         }
 578                         parents=parents->next;
 579                 }
 580                 /*
 581                  * work_item is a commit all of whose children
 582                  * have already been emitted. we can emit it now.
 583                  */
 584                 *pptr = work_node->list_item;
 585                 pptr = &(*pptr)->next;
 586                 *pptr = NULL;
 587                 work_item->object.util = NULL;
 588         }
 589         free(nodes);
 590 }