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 int parse_commit_buffer(struct commit *item, void *buffer, unsigned long size)
  95 {
  96         void *bufptr = buffer;
  97         unsigned char parent[20];
  98         struct commit_list **pptr;
  99
 100         if (item->object.parsed)
 101                 return 0;
 102         item->object.parsed = 1;
 103         get_sha1_hex(bufptr + 5, parent);
 104         item->tree = lookup_tree(parent);
 105         if (item->tree)
 106                 add_ref(&item->object, &item->tree->object);
 107         bufptr += 46; /* "tree " + "hex sha1" + "\n" */
 108         pptr = &item->parents;
 109         while (!memcmp(bufptr, "parent ", 7) &&
 110                !get_sha1_hex(bufptr + 7, parent)) {
 111                 struct commit *new_parent = lookup_commit(parent);
 112                 if (new_parent) {
 113                         pptr = &commit_list_insert(new_parent, pptr)->next;
 114                         add_ref(&item->object, &new_parent->object);
 115                 }
 116                 bufptr += 48;
 117         }
 118         item->date = parse_commit_date(bufptr);
 119         return 0;
 120 }
 121
 122 int parse_commit(struct commit *item)
 123 {
 124         char type[20];
 125         void *buffer;
 126         unsigned long size;
 127         int ret;
 128
 129         if (item->object.parsed)
 130                 return 0;
 131         buffer = read_sha1_file(item->object.sha1, type, &size);
 132         if (!buffer)
 133                 return error("Could not read %s",
 134                              sha1_to_hex(item->object.sha1));
 135         if (strcmp(type, commit_type)) {
 136                 free(buffer);
 137                 return error("Object %s not a commit",
 138                              sha1_to_hex(item->object.sha1));
 139         }
 140         ret = parse_commit_buffer(item, buffer, size);
 141         if (!ret) {
 142                 item->buffer = buffer;
 143                 return 0;
 144         }
 145         free(buffer);
 146         return ret;
 147 }
 148
 149 struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
 150 {
 151         struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
 152         new_list->item = item;
 153         new_list->next = *list_p;
 154         *list_p = new_list;
 155         return new_list;
 156 }
 157
 158 void free_commit_list(struct commit_list *list)
 159 {
 160         while (list) {
 161                 struct commit_list *temp = list;
 162                 list = temp->next;
 163                 free(temp);
 164         }
 165 }
 166
 167 struct commit_list * insert_by_date(struct commit *item, struct commit_list **list)
 168 {
 169         struct commit_list **pp = list;
 170         struct commit_list *p;
 171         while ((p = *pp) != NULL) {
 172                 if (p->item->date < item->date) {
 173                         break;
 174                 }
 175                 pp = &p->next;
 176         }
 177         return commit_list_insert(item, pp);
 178 }
 179
 180
 181 void sort_by_date(struct commit_list **list)
 182 {
 183         struct commit_list *ret = NULL;
 184         while (*list) {
 185                 insert_by_date((*list)->item, &ret);
 186                 *list = (*list)->next;
 187         }
 188         *list = ret;
 189 }
 190
 191 struct commit *pop_most_recent_commit(struct commit_list **list,
 192                                       unsigned int mark)
 193 {
 194         struct commit *ret = (*list)->item;
 195         struct commit_list *parents = ret->parents;
 196         struct commit_list *old = *list;
 197
 198         *list = (*list)->next;
 199         free(old);
 200
 201         while (parents) {
 202                 struct commit *commit = parents->item;
 203                 parse_commit(commit);
 204                 if (!(commit->object.flags & mark)) {
 205                         commit->object.flags |= mark;
 206                         insert_by_date(commit, list);
 207                 }
 208                 parents = parents->next;
 209         }
 210         return ret;
 211 }
 212
 213 /*
 214  * Generic support for pretty-printing the header
 215  */
 216 static int get_one_line(const char *msg, unsigned long len)
 217 {
 218         int ret = 0;
 219
 220         while (len--) {
 221                 char c = *msg++;
 222                 ret++;
 223                 if (c == '\n')
 224                         break;
 225                 if (!c)
 226                         return 0;
 227         }
 228         return ret;
 229 }
 230
 231 static int add_user_info(const char *what, enum cmit_fmt fmt, char *buf, const char *line)
 232 {
 233         char *date;
 234         unsigned int namelen;
 235         unsigned long time;
 236         int tz, ret;
 237
 238         date = strchr(line, '>');
 239         if (!date)
 240                 return 0;
 241         namelen = ++date - line;
 242         time = strtoul(date, &date, 10);
 243         tz = strtol(date, NULL, 10);
 244
 245         ret = sprintf(buf, "%s: %.*s\n", what, namelen, line);
 246         if (fmt == CMIT_FMT_MEDIUM)
 247                 ret += sprintf(buf + ret, "Date:   %s\n", show_date(time, tz));
 248         return ret;
 249 }
 250
 251 static int is_empty_line(const char *line, int len)
 252 {
 253         while (len && isspace(line[len-1]))
 254                 len--;
 255         return !len;
 256 }
 257
 258 static int add_parent_info(enum cmit_fmt fmt, char *buf, const char *line, int parents)
 259 {
 260         int offset = 0;
 261         switch (parents) {
 262         case 1:
 263                 break;
 264         case 2:
 265                 /* Go back to the previous line: 40 characters of previous parent, and one '\n' */
 266                 offset = sprintf(buf, "Merge: %.40s\n", line-41);
 267                 /* Fallthrough */
 268         default:
 269                 /* Replace the previous '\n' with a space */
 270                 buf[offset-1] = ' ';
 271                 offset += sprintf(buf + offset, "%.40s\n", line+7);
 272         }
 273         return offset;
 274 }
 275
 276 unsigned long pretty_print_commit(enum cmit_fmt fmt, const char *msg, unsigned long len, char *buf, unsigned long space)
 277 {
 278         int hdr = 1, body = 0;
 279         unsigned long offset = 0;
 280         int parents = 0;
 281
 282         for (;;) {
 283                 const char *line = msg;
 284                 int linelen = get_one_line(msg, len);
 285
 286                 if (!linelen)
 287                         break;
 288
 289                 /*
 290                  * We want some slop for indentation and a possible
 291                  * final "...". Thus the "+ 20".
 292                  */
 293                 if (offset + linelen + 20 > space) {
 294                         memcpy(buf + offset, "    ...\n", 8);
 295                         offset += 8;
 296                         break;
 297                 }
 298
 299                 msg += linelen;
 300                 len -= linelen;
 301                 if (hdr) {
 302                         if (linelen == 1) {
 303                                 hdr = 0;
 304                                 buf[offset++] = '\n';
 305                                 continue;
 306                         }
 307                         if (fmt == CMIT_FMT_RAW) {
 308                                 memcpy(buf + offset, line, linelen);
 309                                 offset += linelen;
 310                                 continue;
 311                         }
 312                         if (!memcmp(line, "parent ", 7)) {
 313                                 if (linelen != 48)
 314                                         die("bad parent line in commit");
 315                                 offset += add_parent_info(fmt, buf + offset, line, ++parents);
 316                         }
 317                         if (!memcmp(line, "author ", 7))
 318                                 offset += add_user_info("Author", fmt, buf + offset, line + 7);
 319                         if (fmt == CMIT_FMT_FULL) {
 320                                 if (!memcmp(line, "committer ", 10))
 321                                         offset += add_user_info("Commit", fmt, buf + offset, line + 10);
 322                         }
 323                         continue;
 324                 }
 325
 326                 if (is_empty_line(line, linelen)) {
 327                         if (!body)
 328                                 continue;
 329                         if (fmt == CMIT_FMT_SHORT)
 330                                 break;
 331                 } else {
 332                         body = 1;
 333                 }
 334                 memset(buf + offset, ' ', 4);
 335                 memcpy(buf + offset + 4, line, linelen);
 336                 offset += linelen + 4;
 337         }
 338         /* Make sure there is an EOLN */
 339         if (buf[offset - 1] != '\n')
 340                 buf[offset++] = '\n';
 341         buf[offset] = '\0';
 342         return offset;
 343 }
 344
 345 struct commit *pop_commit(struct commit_list **stack)
 346 {
 347         struct commit_list *top = *stack;
 348         struct commit *item = top ? top->item : NULL;
 349
 350         if (top) {
 351                 *stack = top->next;
 352                 free(top);
 353         }
 354         return item;
 355 }
 356
 357 int count_parents(struct commit * commit)
 358 {
 359         int count = 0;
 360         struct commit_list * parents = commit->parents;
 361         for (count=0;parents; parents=parents->next,count++)
 362           ;
 363         return count;
 364 }
 365
 366 /*
 367  * Performs an in-place topological sort on the list supplied.
 368  */
 369 void sort_in_topological_order(struct commit_list ** list)
 370 {
 371         struct commit_list * next = *list;
 372         struct commit_list * work = NULL;
 373         struct commit_list ** pptr = list;
 374         struct sort_node * nodes;
 375         struct sort_node * next_nodes;
 376         int count = 0;
 377
 378         /* determine the size of the list */
 379         while (next) {
 380                 next = next->next;
 381                 count++;
 382         }
 383         /* allocate an array to help sort the list */
 384         nodes = xcalloc(count, sizeof(*nodes));
 385         /* link the list to the array */
 386         next_nodes = nodes;
 387         next=*list;
 388         while (next) {
 389                 next_nodes->list_item = next;
 390                 next->item->object.util = next_nodes;
 391                 next_nodes++;
 392                 next = next->next;
 393         }
 394         /* update the indegree */
 395         next=*list;
 396         while (next) {
 397                 struct commit_list * parents = next->item->parents;
 398                 while (parents) {
 399                         struct commit * parent=parents->item;
 400                         struct sort_node * pn = (struct sort_node *)parent->object.util;
 401
 402                         if (pn)
 403                                 pn->indegree++;
 404                         parents=parents->next;
 405                 }
 406                 next=next->next;
 407         }
 408         /*
 409          * find the tips
 410          *
 411          * tips are nodes not reachable from any other node in the list
 412          *
 413          * the tips serve as a starting set for the work queue.
 414          */
 415         next=*list;
 416         while (next) {
 417                 struct sort_node * node = (struct sort_node *)next->item->object.util;
 418
 419                 if (node->indegree == 0) {
 420                         commit_list_insert(next->item, &work);
 421                 }
 422                 next=next->next;
 423         }
 424         /* process the list in topological order */
 425         while (work) {
 426                 struct commit * work_item = pop_commit(&work);
 427                 struct sort_node * work_node = (struct sort_node *)work_item->object.util;
 428                 struct commit_list * parents = work_item->parents;
 429
 430                 while (parents) {
 431                         struct commit * parent=parents->item;
 432                         struct sort_node * pn = (struct sort_node *)parent->object.util;
 433
 434                         if (pn) {
 435                                 /*
 436                                  * parents are only enqueued for emission
 437                                  * when all their children have been emitted thereby
 438                                  * guaranteeing topological order.
 439                                  */
 440                                 pn->indegree--;
 441                                 if (!pn->indegree)
 442                                         commit_list_insert(parent, &work);
 443                         }
 444                         parents=parents->next;
 445                 }
 446                 /*
 447                  * work_item is a commit all of whose children
 448                  * have already been emitted. we can emit it now.
 449                  */
 450                 *pptr = work_node->list_item;
 451                 pptr = &(*pptr)->next;
 452                 *pptr = NULL;
 453                 work_item->object.util = NULL;
 454         }
 455         free(nodes);
 456 }