Andrew's git / gitweb.git / commit.c
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commit.con commit Try to find the optimum merge base while resolving. (9585e40)
   1#include <ctype.h>
   2#include "tag.h"
   3#include "commit.h"
   4#include "cache.h"
   5
   6struct 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
  22const char *commit_type = "commit";
  23
  24enum 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
  41static struct commit *check_commit(struct object *obj,
  42                                   const unsigned char *sha1,
  43                                   int quiet)
  44{
  45        if (obj->type != commit_type) {
  46                if (!quiet)
  47                        error("Object %s is a %s, not a commit",
  48                              sha1_to_hex(sha1), obj->type);
  49                return NULL;
  50        }
  51        return (struct commit *) obj;
  52}
  53
  54struct commit *lookup_commit_reference_gently(const unsigned char *sha1,
  55                                              int quiet)
  56{
  57        struct object *obj = deref_tag(parse_object(sha1));
  58
  59        if (!obj)
  60                return NULL;
  61        return check_commit(obj, sha1, quiet);
  62}
  63
  64struct commit *lookup_commit_reference(const unsigned char *sha1)
  65{
  66        return lookup_commit_reference_gently(sha1, 0);
  67}
  68
  69struct commit *lookup_commit(const unsigned char *sha1)
  70{
  71        struct object *obj = lookup_object(sha1);
  72        if (!obj) {
  73                struct commit *ret = xmalloc(sizeof(struct commit));
  74                memset(ret, 0, sizeof(struct commit));
  75                created_object(sha1, &ret->object);
  76                ret->object.type = commit_type;
  77                return ret;
  78        }
  79        if (!obj->type)
  80                obj->type = commit_type;
  81        return check_commit(obj, sha1, 0);
  82}
  83
  84static unsigned long parse_commit_date(const char *buf)
  85{
  86        unsigned long date;
  87
  88        if (memcmp(buf, "author", 6))
  89                return 0;
  90        while (*buf++ != '\n')
  91                /* nada */;
  92        if (memcmp(buf, "committer", 9))
  93                return 0;
  94        while (*buf++ != '>')
  95                /* nada */;
  96        date = strtoul(buf, NULL, 10);
  97        if (date == ULONG_MAX)
  98                date = 0;
  99        return date;
 100}
 101
 102static struct commit_graft {
 103        unsigned char sha1[20];
 104        int nr_parent;
 105        unsigned char parent[0][20]; /* more */
 106} **commit_graft;
 107static int commit_graft_alloc, commit_graft_nr;
 108
 109static int commit_graft_pos(const unsigned char *sha1)
 110{
 111        int lo, hi;
 112        lo = 0;
 113        hi = commit_graft_nr;
 114        while (lo < hi) {
 115                int mi = (lo + hi) / 2;
 116                struct commit_graft *graft = commit_graft[mi];
 117                int cmp = memcmp(sha1, graft->sha1, 20);
 118                if (!cmp)
 119                        return mi;
 120                if (cmp < 0)
 121                        hi = mi;
 122                else
 123                        lo = mi + 1;
 124        }
 125        return -lo - 1;
 126}
 127
 128static void prepare_commit_graft(void)
 129{
 130        char *graft_file = get_graft_file();
 131        FILE *fp = fopen(graft_file, "r");
 132        char buf[1024];
 133        if (!fp) {
 134                commit_graft = (struct commit_graft **) "hack";
 135                return;
 136        }
 137        while (fgets(buf, sizeof(buf), fp)) {
 138                /* The format is just "Commit Parent1 Parent2 ...\n" */
 139                int len = strlen(buf);
 140                int i;
 141                struct commit_graft *graft = NULL;
 142
 143                if (buf[len-1] == '\n')
 144                        buf[--len] = 0;
 145                if (buf[0] == '#')
 146                        continue;
 147                if ((len + 1) % 41) {
 148                bad_graft_data:
 149                        error("bad graft data: %s", buf);
 150                        free(graft);
 151                        continue;
 152                }
 153                i = (len + 1) / 41 - 1;
 154                graft = xmalloc(sizeof(*graft) + 20 * i);
 155                graft->nr_parent = i;
 156                if (get_sha1_hex(buf, graft->sha1))
 157                        goto bad_graft_data;
 158                for (i = 40; i < len; i += 41) {
 159                        if (buf[i] != ' ')
 160                                goto bad_graft_data;
 161                        if (get_sha1_hex(buf + i + 1, graft->parent[i/41]))
 162                                goto bad_graft_data;
 163                }
 164                i = commit_graft_pos(graft->sha1);
 165                if (0 <= i) {
 166                        error("duplicate graft data: %s", buf);
 167                        free(graft);
 168                        continue;
 169                }
 170                i = -i - 1;
 171                if (commit_graft_alloc <= ++commit_graft_nr) {
 172                        commit_graft_alloc = alloc_nr(commit_graft_alloc);
 173                        commit_graft = xrealloc(commit_graft,
 174                                                sizeof(*commit_graft) *
 175                                                commit_graft_alloc);
 176                }
 177                if (i < commit_graft_nr)
 178                        memmove(commit_graft + i + 1,
 179                                commit_graft + i,
 180                                (commit_graft_nr - i - 1) *
 181                                sizeof(*commit_graft));
 182                commit_graft[i] = graft;
 183        }
 184        fclose(fp);
 185}
 186
 187static struct commit_graft *lookup_commit_graft(const unsigned char *sha1)
 188{
 189        int pos;
 190        if (!commit_graft)
 191                prepare_commit_graft();
 192        pos = commit_graft_pos(sha1);
 193        if (pos < 0)
 194                return NULL;
 195        return commit_graft[pos];
 196}
 197
 198int parse_commit_buffer(struct commit *item, void *buffer, unsigned long size)
 199{
 200        char *bufptr = buffer;
 201        unsigned char parent[20];
 202        struct commit_list **pptr;
 203        struct commit_graft *graft;
 204
 205        if (item->object.parsed)
 206                return 0;
 207        item->object.parsed = 1;
 208        if (memcmp(bufptr, "tree ", 5))
 209                return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
 210        if (get_sha1_hex(bufptr + 5, parent) < 0)
 211                return error("bad tree pointer in commit %s\n", sha1_to_hex(item->object.sha1));
 212        item->tree = lookup_tree(parent);
 213        if (item->tree)
 214                add_ref(&item->object, &item->tree->object);
 215        bufptr += 46; /* "tree " + "hex sha1" + "\n" */
 216        pptr = &item->parents;
 217
 218        graft = lookup_commit_graft(item->object.sha1);
 219        while (!memcmp(bufptr, "parent ", 7)) {
 220                struct commit *new_parent;
 221
 222                if (get_sha1_hex(bufptr + 7, parent) || bufptr[47] != '\n')
 223                        return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
 224                bufptr += 48;
 225                if (graft)
 226                        continue;
 227                new_parent = lookup_commit(parent);
 228                if (new_parent) {
 229                        pptr = &commit_list_insert(new_parent, pptr)->next;
 230                        add_ref(&item->object, &new_parent->object);
 231                }
 232        }
 233        if (graft) {
 234                int i;
 235                struct commit *new_parent;
 236                for (i = 0; i < graft->nr_parent; i++) {
 237                        new_parent = lookup_commit(graft->parent[i]);
 238                        if (!new_parent)
 239                                continue;
 240                        pptr = &commit_list_insert(new_parent, pptr)->next;
 241                        add_ref(&item->object, &new_parent->object);
 242                }
 243        }
 244        item->date = parse_commit_date(bufptr);
 245        return 0;
 246}
 247
 248int parse_commit(struct commit *item)
 249{
 250        char type[20];
 251        void *buffer;
 252        unsigned long size;
 253        int ret;
 254
 255        if (item->object.parsed)
 256                return 0;
 257        buffer = read_sha1_file(item->object.sha1, type, &size);
 258        if (!buffer)
 259                return error("Could not read %s",
 260                             sha1_to_hex(item->object.sha1));
 261        if (strcmp(type, commit_type)) {
 262                free(buffer);
 263                return error("Object %s not a commit",
 264                             sha1_to_hex(item->object.sha1));
 265        }
 266        ret = parse_commit_buffer(item, buffer, size);
 267        if (!ret) {
 268                item->buffer = buffer;
 269                return 0;
 270        }
 271        free(buffer);
 272        return ret;
 273}
 274
 275struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
 276{
 277        struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
 278        new_list->item = item;
 279        new_list->next = *list_p;
 280        *list_p = new_list;
 281        return new_list;
 282}
 283
 284void free_commit_list(struct commit_list *list)
 285{
 286        while (list) {
 287                struct commit_list *temp = list;
 288                list = temp->next;
 289                free(temp);
 290        }
 291}
 292
 293struct commit_list * insert_by_date(struct commit *item, struct commit_list **list)
 294{
 295        struct commit_list **pp = list;
 296        struct commit_list *p;
 297        while ((p = *pp) != NULL) {
 298                if (p->item->date < item->date) {
 299                        break;
 300                }
 301                pp = &p->next;
 302        }
 303        return commit_list_insert(item, pp);
 304}
 305
 306        
 307void sort_by_date(struct commit_list **list)
 308{
 309        struct commit_list *ret = NULL;
 310        while (*list) {
 311                insert_by_date((*list)->item, &ret);
 312                *list = (*list)->next;
 313        }
 314        *list = ret;
 315}
 316
 317struct commit *pop_most_recent_commit(struct commit_list **list,
 318                                      unsigned int mark)
 319{
 320        struct commit *ret = (*list)->item;
 321        struct commit_list *parents = ret->parents;
 322        struct commit_list *old = *list;
 323
 324        *list = (*list)->next;
 325        free(old);
 326
 327        while (parents) {
 328                struct commit *commit = parents->item;
 329                parse_commit(commit);
 330                if (!(commit->object.flags & mark)) {
 331                        commit->object.flags |= mark;
 332                        insert_by_date(commit, list);
 333                }
 334                parents = parents->next;
 335        }
 336        return ret;
 337}
 338
 339/*
 340 * Generic support for pretty-printing the header
 341 */
 342static int get_one_line(const char *msg, unsigned long len)
 343{
 344        int ret = 0;
 345
 346        while (len--) {
 347                char c = *msg++;
 348                ret++;
 349                if (c == '\n')
 350                        break;
 351                if (!c)
 352                        return 0;
 353        }
 354        return ret;
 355}
 356
 357static int add_user_info(const char *what, enum cmit_fmt fmt, char *buf, const char *line)
 358{
 359        char *date;
 360        unsigned int namelen;
 361        unsigned long time;
 362        int tz, ret;
 363
 364        if (fmt == CMIT_FMT_ONELINE)
 365                return 0;
 366        date = strchr(line, '>');
 367        if (!date)
 368                return 0;
 369        namelen = ++date - line;
 370        time = strtoul(date, &date, 10);
 371        tz = strtol(date, NULL, 10);
 372
 373        ret = sprintf(buf, "%s: %.*s\n", what, namelen, line);
 374        if (fmt == CMIT_FMT_MEDIUM)
 375                ret += sprintf(buf + ret, "Date:   %s\n", show_date(time, tz));
 376        return ret;
 377}
 378
 379static int is_empty_line(const char *line, int len)
 380{
 381        while (len && isspace(line[len-1]))
 382                len--;
 383        return !len;
 384}
 385
 386static int add_parent_info(enum cmit_fmt fmt, char *buf, const char *line, int parents)
 387{
 388        int offset = 0;
 389
 390        if (fmt == CMIT_FMT_ONELINE)
 391                return offset;
 392        switch (parents) {
 393        case 1:
 394                break;
 395        case 2:
 396                /* Go back to the previous line: 40 characters of previous parent, and one '\n' */
 397                offset = sprintf(buf, "Merge: %.40s\n", line-41);
 398                /* Fallthrough */
 399        default:
 400                /* Replace the previous '\n' with a space */
 401                buf[offset-1] = ' ';
 402                offset += sprintf(buf + offset, "%.40s\n", line+7);
 403        }
 404        return offset;
 405}
 406
 407unsigned long pretty_print_commit(enum cmit_fmt fmt, const char *msg, unsigned long len, char *buf, unsigned long space)
 408{
 409        int hdr = 1, body = 0;
 410        unsigned long offset = 0;
 411        int parents = 0;
 412        int indent = (fmt == CMIT_FMT_ONELINE) ? 0 : 4;
 413
 414        for (;;) {
 415                const char *line = msg;
 416                int linelen = get_one_line(msg, len);
 417
 418                if (!linelen)
 419                        break;
 420
 421                /*
 422                 * We want some slop for indentation and a possible
 423                 * final "...". Thus the "+ 20".
 424                 */
 425                if (offset + linelen + 20 > space) {
 426                        memcpy(buf + offset, "    ...\n", 8);
 427                        offset += 8;
 428                        break;
 429                }
 430
 431                msg += linelen;
 432                len -= linelen;
 433                if (hdr) {
 434                        if (linelen == 1) {
 435                                hdr = 0;
 436                                if (fmt != CMIT_FMT_ONELINE)
 437                                        buf[offset++] = '\n';
 438                                continue;
 439                        }
 440                        if (fmt == CMIT_FMT_RAW) {
 441                                memcpy(buf + offset, line, linelen);
 442                                offset += linelen;
 443                                continue;
 444                        }
 445                        if (!memcmp(line, "parent ", 7)) {
 446                                if (linelen != 48)
 447                                        die("bad parent line in commit");
 448                                offset += add_parent_info(fmt, buf + offset, line, ++parents);
 449                        }
 450                        if (!memcmp(line, "author ", 7))
 451                                offset += add_user_info("Author", fmt, buf + offset, line + 7);
 452                        if (fmt == CMIT_FMT_FULL) {
 453                                if (!memcmp(line, "committer ", 10))
 454                                        offset += add_user_info("Commit", fmt, buf + offset, line + 10);
 455                        }
 456                        continue;
 457                }
 458
 459                if (is_empty_line(line, linelen)) {
 460                        if (!body)
 461                                continue;
 462                        if (fmt == CMIT_FMT_SHORT)
 463                                break;
 464                } else {
 465                        body = 1;
 466                }
 467
 468                memset(buf + offset, ' ', indent);
 469                memcpy(buf + offset + indent, line, linelen);
 470                offset += linelen + indent;
 471                if (fmt == CMIT_FMT_ONELINE)
 472                        break;
 473        }
 474        if (fmt == CMIT_FMT_ONELINE) {
 475                /* We do not want the terminating newline */
 476                if (buf[offset - 1] == '\n')
 477                        offset--;
 478        }
 479        else {
 480                /* Make sure there is an EOLN */
 481                if (buf[offset - 1] != '\n')
 482                        buf[offset++] = '\n';
 483        }
 484        buf[offset] = '\0';
 485        return offset;
 486}
 487
 488struct commit *pop_commit(struct commit_list **stack)
 489{
 490        struct commit_list *top = *stack;
 491        struct commit *item = top ? top->item : NULL;
 492
 493        if (top) {
 494                *stack = top->next;
 495                free(top);
 496        }
 497        return item;
 498}
 499
 500int count_parents(struct commit * commit)
 501{
 502        int count = 0;
 503        struct commit_list * parents = commit->parents;
 504        for (count=0;parents; parents=parents->next,count++)
 505          ;
 506        return count;
 507}
 508
 509/*
 510 * Performs an in-place topological sort on the list supplied.
 511 */
 512void sort_in_topological_order(struct commit_list ** list)
 513{
 514        struct commit_list * next = *list;
 515        struct commit_list * work = NULL;
 516        struct commit_list ** pptr = list;
 517        struct sort_node * nodes;
 518        struct sort_node * next_nodes;
 519        int count = 0;
 520
 521        /* determine the size of the list */
 522        while (next) {
 523                next = next->next;
 524                count++;
 525        }
 526        /* allocate an array to help sort the list */
 527        nodes = xcalloc(count, sizeof(*nodes));
 528        /* link the list to the array */
 529        next_nodes = nodes;
 530        next=*list;
 531        while (next) {
 532                next_nodes->list_item = next;
 533                next->item->object.util = next_nodes;
 534                next_nodes++;
 535                next = next->next;
 536        }
 537        /* update the indegree */
 538        next=*list;
 539        while (next) {
 540                struct commit_list * parents = next->item->parents;
 541                while (parents) {
 542                        struct commit * parent=parents->item;
 543                        struct sort_node * pn = (struct sort_node *)parent->object.util;
 544                        
 545                        if (pn)
 546                                pn->indegree++;
 547                        parents=parents->next;
 548                }
 549                next=next->next;
 550        }
 551        /* 
 552         * find the tips
 553         *
 554         * tips are nodes not reachable from any other node in the list 
 555         * 
 556         * the tips serve as a starting set for the work queue.
 557         */
 558        next=*list;
 559        while (next) {
 560                struct sort_node * node = (struct sort_node *)next->item->object.util;
 561
 562                if (node->indegree == 0) {
 563                        commit_list_insert(next->item, &work);
 564                }
 565                next=next->next;
 566        }
 567        /* process the list in topological order */
 568        while (work) {
 569                struct commit * work_item = pop_commit(&work);
 570                struct sort_node * work_node = (struct sort_node *)work_item->object.util;
 571                struct commit_list * parents = work_item->parents;
 572
 573                while (parents) {
 574                        struct commit * parent=parents->item;
 575                        struct sort_node * pn = (struct sort_node *)parent->object.util;
 576                        
 577                        if (pn) {
 578                                /* 
 579                                 * parents are only enqueued for emission 
 580                                 * when all their children have been emitted thereby
 581                                 * guaranteeing topological order.
 582                                 */
 583                                pn->indegree--;
 584                                if (!pn->indegree) 
 585                                        commit_list_insert(parent, &work);
 586                        }
 587                        parents=parents->next;
 588                }
 589                /*
 590                 * work_item is a commit all of whose children
 591                 * have already been emitted. we can emit it now.
 592                 */
 593                *pptr = work_node->list_item;
 594                pptr = &(*pptr)->next;
 595                *pptr = NULL;
 596                work_item->object.util = NULL;
 597        }
 598        free(nodes);
 599}