Andrew's git / gitweb.git / commit.c
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commit.con commit Merge branch 'jc/maint-reset' into maint (4df0d7a)
   1#include "cache.h"
   2#include "tag.h"
   3#include "commit.h"
   4#include "pkt-line.h"
   5#include "utf8.h"
   6#include "diff.h"
   7#include "revision.h"
   8
   9int save_commit_buffer = 1;
  10
  11const char *commit_type = "commit";
  12
  13static struct commit *check_commit(struct object *obj,
  14                                   const unsigned char *sha1,
  15                                   int quiet)
  16{
  17        if (obj->type != OBJ_COMMIT) {
  18                if (!quiet)
  19                        error("Object %s is a %s, not a commit",
  20                              sha1_to_hex(sha1), typename(obj->type));
  21                return NULL;
  22        }
  23        return (struct commit *) obj;
  24}
  25
  26struct commit *lookup_commit_reference_gently(const unsigned char *sha1,
  27                                              int quiet)
  28{
  29        struct object *obj = deref_tag(parse_object(sha1), NULL, 0);
  30
  31        if (!obj)
  32                return NULL;
  33        return check_commit(obj, sha1, quiet);
  34}
  35
  36struct commit *lookup_commit_reference(const unsigned char *sha1)
  37{
  38        return lookup_commit_reference_gently(sha1, 0);
  39}
  40
  41struct commit *lookup_commit(const unsigned char *sha1)
  42{
  43        struct object *obj = lookup_object(sha1);
  44        if (!obj)
  45                return create_object(sha1, OBJ_COMMIT, alloc_commit_node());
  46        if (!obj->type)
  47                obj->type = OBJ_COMMIT;
  48        return check_commit(obj, sha1, 0);
  49}
  50
  51static unsigned long parse_commit_date(const char *buf, const char *tail)
  52{
  53        unsigned long date;
  54        const char *dateptr;
  55
  56        if (buf + 6 >= tail)
  57                return 0;
  58        if (memcmp(buf, "author", 6))
  59                return 0;
  60        while (buf < tail && *buf++ != '\n')
  61                /* nada */;
  62        if (buf + 9 >= tail)
  63                return 0;
  64        if (memcmp(buf, "committer", 9))
  65                return 0;
  66        while (buf < tail && *buf++ != '>')
  67                /* nada */;
  68        if (buf >= tail)
  69                return 0;
  70        dateptr = buf;
  71        while (buf < tail && *buf++ != '\n')
  72                /* nada */;
  73        if (buf >= tail)
  74                return 0;
  75        /* dateptr < buf && buf[-1] == '\n', so strtoul will stop at buf-1 */
  76        date = strtoul(dateptr, NULL, 10);
  77        if (date == ULONG_MAX)
  78                date = 0;
  79        return date;
  80}
  81
  82static struct commit_graft **commit_graft;
  83static int commit_graft_alloc, commit_graft_nr;
  84
  85static int commit_graft_pos(const unsigned char *sha1)
  86{
  87        int lo, hi;
  88        lo = 0;
  89        hi = commit_graft_nr;
  90        while (lo < hi) {
  91                int mi = (lo + hi) / 2;
  92                struct commit_graft *graft = commit_graft[mi];
  93                int cmp = hashcmp(sha1, graft->sha1);
  94                if (!cmp)
  95                        return mi;
  96                if (cmp < 0)
  97                        hi = mi;
  98                else
  99                        lo = mi + 1;
 100        }
 101        return -lo - 1;
 102}
 103
 104int register_commit_graft(struct commit_graft *graft, int ignore_dups)
 105{
 106        int pos = commit_graft_pos(graft->sha1);
 107
 108        if (0 <= pos) {
 109                if (ignore_dups)
 110                        free(graft);
 111                else {
 112                        free(commit_graft[pos]);
 113                        commit_graft[pos] = graft;
 114                }
 115                return 1;
 116        }
 117        pos = -pos - 1;
 118        if (commit_graft_alloc <= ++commit_graft_nr) {
 119                commit_graft_alloc = alloc_nr(commit_graft_alloc);
 120                commit_graft = xrealloc(commit_graft,
 121                                        sizeof(*commit_graft) *
 122                                        commit_graft_alloc);
 123        }
 124        if (pos < commit_graft_nr)
 125                memmove(commit_graft + pos + 1,
 126                        commit_graft + pos,
 127                        (commit_graft_nr - pos - 1) *
 128                        sizeof(*commit_graft));
 129        commit_graft[pos] = graft;
 130        return 0;
 131}
 132
 133struct commit_graft *read_graft_line(char *buf, int len)
 134{
 135        /* The format is just "Commit Parent1 Parent2 ...\n" */
 136        int i;
 137        struct commit_graft *graft = NULL;
 138
 139        if (buf[len-1] == '\n')
 140                buf[--len] = 0;
 141        if (buf[0] == '#' || buf[0] == '\0')
 142                return NULL;
 143        if ((len + 1) % 41) {
 144        bad_graft_data:
 145                error("bad graft data: %s", buf);
 146                free(graft);
 147                return NULL;
 148        }
 149        i = (len + 1) / 41 - 1;
 150        graft = xmalloc(sizeof(*graft) + 20 * i);
 151        graft->nr_parent = i;
 152        if (get_sha1_hex(buf, graft->sha1))
 153                goto bad_graft_data;
 154        for (i = 40; i < len; i += 41) {
 155                if (buf[i] != ' ')
 156                        goto bad_graft_data;
 157                if (get_sha1_hex(buf + i + 1, graft->parent[i/41]))
 158                        goto bad_graft_data;
 159        }
 160        return graft;
 161}
 162
 163int read_graft_file(const char *graft_file)
 164{
 165        FILE *fp = fopen(graft_file, "r");
 166        char buf[1024];
 167        if (!fp)
 168                return -1;
 169        while (fgets(buf, sizeof(buf), fp)) {
 170                /* The format is just "Commit Parent1 Parent2 ...\n" */
 171                int len = strlen(buf);
 172                struct commit_graft *graft = read_graft_line(buf, len);
 173                if (!graft)
 174                        continue;
 175                if (register_commit_graft(graft, 1))
 176                        error("duplicate graft data: %s", buf);
 177        }
 178        fclose(fp);
 179        return 0;
 180}
 181
 182static void prepare_commit_graft(void)
 183{
 184        static int commit_graft_prepared;
 185        char *graft_file;
 186
 187        if (commit_graft_prepared)
 188                return;
 189        graft_file = get_graft_file();
 190        read_graft_file(graft_file);
 191        /* make sure shallows are read */
 192        is_repository_shallow();
 193        commit_graft_prepared = 1;
 194}
 195
 196struct commit_graft *lookup_commit_graft(const unsigned char *sha1)
 197{
 198        int pos;
 199        prepare_commit_graft();
 200        pos = commit_graft_pos(sha1);
 201        if (pos < 0)
 202                return NULL;
 203        return commit_graft[pos];
 204}
 205
 206int write_shallow_commits(int fd, int use_pack_protocol)
 207{
 208        int i, count = 0;
 209        for (i = 0; i < commit_graft_nr; i++)
 210                if (commit_graft[i]->nr_parent < 0) {
 211                        const char *hex =
 212                                sha1_to_hex(commit_graft[i]->sha1);
 213                        count++;
 214                        if (use_pack_protocol)
 215                                packet_write(fd, "shallow %s", hex);
 216                        else {
 217                                if (write_in_full(fd, hex,  40) != 40)
 218                                        break;
 219                                if (write_in_full(fd, "\n", 1) != 1)
 220                                        break;
 221                        }
 222                }
 223        return count;
 224}
 225
 226int unregister_shallow(const unsigned char *sha1)
 227{
 228        int pos = commit_graft_pos(sha1);
 229        if (pos < 0)
 230                return -1;
 231        if (pos + 1 < commit_graft_nr)
 232                memcpy(commit_graft + pos, commit_graft + pos + 1,
 233                                sizeof(struct commit_graft *)
 234                                * (commit_graft_nr - pos - 1));
 235        commit_graft_nr--;
 236        return 0;
 237}
 238
 239int parse_commit_buffer(struct commit *item, void *buffer, unsigned long size)
 240{
 241        char *tail = buffer;
 242        char *bufptr = buffer;
 243        unsigned char parent[20];
 244        struct commit_list **pptr;
 245        struct commit_graft *graft;
 246
 247        if (item->object.parsed)
 248                return 0;
 249        item->object.parsed = 1;
 250        tail += size;
 251        if (tail <= bufptr + 46 || memcmp(bufptr, "tree ", 5) || bufptr[45] != '\n')
 252                return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
 253        if (get_sha1_hex(bufptr + 5, parent) < 0)
 254                return error("bad tree pointer in commit %s",
 255                             sha1_to_hex(item->object.sha1));
 256        item->tree = lookup_tree(parent);
 257        bufptr += 46; /* "tree " + "hex sha1" + "\n" */
 258        pptr = &item->parents;
 259
 260        graft = lookup_commit_graft(item->object.sha1);
 261        while (bufptr + 48 < tail && !memcmp(bufptr, "parent ", 7)) {
 262                struct commit *new_parent;
 263
 264                if (tail <= bufptr + 48 ||
 265                    get_sha1_hex(bufptr + 7, parent) ||
 266                    bufptr[47] != '\n')
 267                        return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
 268                bufptr += 48;
 269                if (graft)
 270                        continue;
 271                new_parent = lookup_commit(parent);
 272                if (new_parent)
 273                        pptr = &commit_list_insert(new_parent, pptr)->next;
 274        }
 275        if (graft) {
 276                int i;
 277                struct commit *new_parent;
 278                for (i = 0; i < graft->nr_parent; i++) {
 279                        new_parent = lookup_commit(graft->parent[i]);
 280                        if (!new_parent)
 281                                continue;
 282                        pptr = &commit_list_insert(new_parent, pptr)->next;
 283                }
 284        }
 285        item->date = parse_commit_date(bufptr, tail);
 286
 287        return 0;
 288}
 289
 290int parse_commit(struct commit *item)
 291{
 292        enum object_type type;
 293        void *buffer;
 294        unsigned long size;
 295        int ret;
 296
 297        if (!item)
 298                return -1;
 299        if (item->object.parsed)
 300                return 0;
 301        buffer = read_sha1_file(item->object.sha1, &type, &size);
 302        if (!buffer)
 303                return error("Could not read %s",
 304                             sha1_to_hex(item->object.sha1));
 305        if (type != OBJ_COMMIT) {
 306                free(buffer);
 307                return error("Object %s not a commit",
 308                             sha1_to_hex(item->object.sha1));
 309        }
 310        ret = parse_commit_buffer(item, buffer, size);
 311        if (save_commit_buffer && !ret) {
 312                item->buffer = buffer;
 313                return 0;
 314        }
 315        free(buffer);
 316        return ret;
 317}
 318
 319struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
 320{
 321        struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
 322        new_list->item = item;
 323        new_list->next = *list_p;
 324        *list_p = new_list;
 325        return new_list;
 326}
 327
 328void free_commit_list(struct commit_list *list)
 329{
 330        while (list) {
 331                struct commit_list *temp = list;
 332                list = temp->next;
 333                free(temp);
 334        }
 335}
 336
 337struct commit_list * insert_by_date(struct commit *item, struct commit_list **list)
 338{
 339        struct commit_list **pp = list;
 340        struct commit_list *p;
 341        while ((p = *pp) != NULL) {
 342                if (p->item->date < item->date) {
 343                        break;
 344                }
 345                pp = &p->next;
 346        }
 347        return commit_list_insert(item, pp);
 348}
 349
 350
 351void sort_by_date(struct commit_list **list)
 352{
 353        struct commit_list *ret = NULL;
 354        while (*list) {
 355                insert_by_date((*list)->item, &ret);
 356                *list = (*list)->next;
 357        }
 358        *list = ret;
 359}
 360
 361struct commit *pop_most_recent_commit(struct commit_list **list,
 362                                      unsigned int mark)
 363{
 364        struct commit *ret = (*list)->item;
 365        struct commit_list *parents = ret->parents;
 366        struct commit_list *old = *list;
 367
 368        *list = (*list)->next;
 369        free(old);
 370
 371        while (parents) {
 372                struct commit *commit = parents->item;
 373                if (!parse_commit(commit) && !(commit->object.flags & mark)) {
 374                        commit->object.flags |= mark;
 375                        insert_by_date(commit, list);
 376                }
 377                parents = parents->next;
 378        }
 379        return ret;
 380}
 381
 382void clear_commit_marks(struct commit *commit, unsigned int mark)
 383{
 384        while (commit) {
 385                struct commit_list *parents;
 386
 387                if (!(mark & commit->object.flags))
 388                        return;
 389
 390                commit->object.flags &= ~mark;
 391
 392                parents = commit->parents;
 393                if (!parents)
 394                        return;
 395
 396                while ((parents = parents->next))
 397                        clear_commit_marks(parents->item, mark);
 398
 399                commit = commit->parents->item;
 400        }
 401}
 402
 403struct commit *pop_commit(struct commit_list **stack)
 404{
 405        struct commit_list *top = *stack;
 406        struct commit *item = top ? top->item : NULL;
 407
 408        if (top) {
 409                *stack = top->next;
 410                free(top);
 411        }
 412        return item;
 413}
 414
 415/*
 416 * Performs an in-place topological sort on the list supplied.
 417 */
 418void sort_in_topological_order(struct commit_list ** list, int lifo)
 419{
 420        struct commit_list *next, *orig = *list;
 421        struct commit_list *work, **insert;
 422        struct commit_list **pptr;
 423
 424        if (!orig)
 425                return;
 426        *list = NULL;
 427
 428        /* Mark them and clear the indegree */
 429        for (next = orig; next; next = next->next) {
 430                struct commit *commit = next->item;
 431                commit->object.flags |= TOPOSORT;
 432                commit->indegree = 0;
 433        }
 434
 435        /* update the indegree */
 436        for (next = orig; next; next = next->next) {
 437                struct commit_list * parents = next->item->parents;
 438                while (parents) {
 439                        struct commit *parent = parents->item;
 440
 441                        if (parent->object.flags & TOPOSORT)
 442                                parent->indegree++;
 443                        parents = parents->next;
 444                }
 445        }
 446
 447        /*
 448         * find the tips
 449         *
 450         * tips are nodes not reachable from any other node in the list
 451         *
 452         * the tips serve as a starting set for the work queue.
 453         */
 454        work = NULL;
 455        insert = &work;
 456        for (next = orig; next; next = next->next) {
 457                struct commit *commit = next->item;
 458
 459                if (!commit->indegree)
 460                        insert = &commit_list_insert(commit, insert)->next;
 461        }
 462
 463        /* process the list in topological order */
 464        if (!lifo)
 465                sort_by_date(&work);
 466
 467        pptr = list;
 468        *list = NULL;
 469        while (work) {
 470                struct commit *commit;
 471                struct commit_list *parents, *work_item;
 472
 473                work_item = work;
 474                work = work_item->next;
 475                work_item->next = NULL;
 476
 477                commit = work_item->item;
 478                for (parents = commit->parents; parents ; parents = parents->next) {
 479                        struct commit *parent=parents->item;
 480
 481                        if (!(parent->object.flags & TOPOSORT))
 482                                continue;
 483
 484                        /*
 485                         * parents are only enqueued for emission
 486                         * when all their children have been emitted thereby
 487                         * guaranteeing topological order.
 488                         */
 489                        if (!--parent->indegree) {
 490                                if (!lifo)
 491                                        insert_by_date(parent, &work);
 492                                else
 493                                        commit_list_insert(parent, &work);
 494                        }
 495                }
 496                /*
 497                 * work_item is a commit all of whose children
 498                 * have already been emitted. we can emit it now.
 499                 */
 500                commit->object.flags &= ~TOPOSORT;
 501                *pptr = work_item;
 502                pptr = &work_item->next;
 503        }
 504}
 505
 506/* merge-base stuff */
 507
 508/* bits #0..15 in revision.h */
 509#define PARENT1         (1u<<16)
 510#define PARENT2         (1u<<17)
 511#define STALE           (1u<<18)
 512#define RESULT          (1u<<19)
 513
 514static const unsigned all_flags = (PARENT1 | PARENT2 | STALE | RESULT);
 515
 516static struct commit *interesting(struct commit_list *list)
 517{
 518        while (list) {
 519                struct commit *commit = list->item;
 520                list = list->next;
 521                if (commit->object.flags & STALE)
 522                        continue;
 523                return commit;
 524        }
 525        return NULL;
 526}
 527
 528static struct commit_list *merge_bases(struct commit *one, struct commit *two)
 529{
 530        struct commit_list *list = NULL;
 531        struct commit_list *result = NULL;
 532
 533        if (one == two)
 534                /* We do not mark this even with RESULT so we do not
 535                 * have to clean it up.
 536                 */
 537                return commit_list_insert(one, &result);
 538
 539        if (parse_commit(one))
 540                return NULL;
 541        if (parse_commit(two))
 542                return NULL;
 543
 544        one->object.flags |= PARENT1;
 545        two->object.flags |= PARENT2;
 546        insert_by_date(one, &list);
 547        insert_by_date(two, &list);
 548
 549        while (interesting(list)) {
 550                struct commit *commit;
 551                struct commit_list *parents;
 552                struct commit_list *n;
 553                int flags;
 554
 555                commit = list->item;
 556                n = list->next;
 557                free(list);
 558                list = n;
 559
 560                flags = commit->object.flags & (PARENT1 | PARENT2 | STALE);
 561                if (flags == (PARENT1 | PARENT2)) {
 562                        if (!(commit->object.flags & RESULT)) {
 563                                commit->object.flags |= RESULT;
 564                                insert_by_date(commit, &result);
 565                        }
 566                        /* Mark parents of a found merge stale */
 567                        flags |= STALE;
 568                }
 569                parents = commit->parents;
 570                while (parents) {
 571                        struct commit *p = parents->item;
 572                        parents = parents->next;
 573                        if ((p->object.flags & flags) == flags)
 574                                continue;
 575                        if (parse_commit(p))
 576                                return NULL;
 577                        p->object.flags |= flags;
 578                        insert_by_date(p, &list);
 579                }
 580        }
 581
 582        /* Clean up the result to remove stale ones */
 583        free_commit_list(list);
 584        list = result; result = NULL;
 585        while (list) {
 586                struct commit_list *n = list->next;
 587                if (!(list->item->object.flags & STALE))
 588                        insert_by_date(list->item, &result);
 589                free(list);
 590                list = n;
 591        }
 592        return result;
 593}
 594
 595struct commit_list *get_merge_bases(struct commit *one,
 596                                        struct commit *two, int cleanup)
 597{
 598        struct commit_list *list;
 599        struct commit **rslt;
 600        struct commit_list *result;
 601        int cnt, i, j;
 602
 603        result = merge_bases(one, two);
 604        if (one == two)
 605                return result;
 606        if (!result || !result->next) {
 607                if (cleanup) {
 608                        clear_commit_marks(one, all_flags);
 609                        clear_commit_marks(two, all_flags);
 610                }
 611                return result;
 612        }
 613
 614        /* There are more than one */
 615        cnt = 0;
 616        list = result;
 617        while (list) {
 618                list = list->next;
 619                cnt++;
 620        }
 621        rslt = xcalloc(cnt, sizeof(*rslt));
 622        for (list = result, i = 0; list; list = list->next)
 623                rslt[i++] = list->item;
 624        free_commit_list(result);
 625
 626        clear_commit_marks(one, all_flags);
 627        clear_commit_marks(two, all_flags);
 628        for (i = 0; i < cnt - 1; i++) {
 629                for (j = i+1; j < cnt; j++) {
 630                        if (!rslt[i] || !rslt[j])
 631                                continue;
 632                        result = merge_bases(rslt[i], rslt[j]);
 633                        clear_commit_marks(rslt[i], all_flags);
 634                        clear_commit_marks(rslt[j], all_flags);
 635                        for (list = result; list; list = list->next) {
 636                                if (rslt[i] == list->item)
 637                                        rslt[i] = NULL;
 638                                if (rslt[j] == list->item)
 639                                        rslt[j] = NULL;
 640                        }
 641                }
 642        }
 643
 644        /* Surviving ones in rslt[] are the independent results */
 645        result = NULL;
 646        for (i = 0; i < cnt; i++) {
 647                if (rslt[i])
 648                        insert_by_date(rslt[i], &result);
 649        }
 650        free(rslt);
 651        return result;
 652}
 653
 654int in_merge_bases(struct commit *commit, struct commit **reference, int num)
 655{
 656        struct commit_list *bases, *b;
 657        int ret = 0;
 658
 659        if (num == 1)
 660                bases = get_merge_bases(commit, *reference, 1);
 661        else
 662                die("not yet");
 663        for (b = bases; b; b = b->next) {
 664                if (!hashcmp(commit->object.sha1, b->item->object.sha1)) {
 665                        ret = 1;
 666                        break;
 667                }
 668        }
 669
 670        free_commit_list(bases);
 671        return ret;
 672}