revision.c

   1 #include "cache.h"
   2 #include "tag.h"
   3 #include "blob.h"
   4 #include "tree.h"
   5 #include "commit.h"
   6 #include "diff.h"
   7 #include "refs.h"
   8 #include "revision.h"
   9 #include "grep.h"
  10 #include "reflog-walk.h"
  11 #include "patch-ids.h"
  12
  13 volatile show_early_output_fn_t show_early_output;
  14
  15 static char *path_name(struct name_path *path, const char *name)
  16 {
  17         struct name_path *p;
  18         char *n, *m;
  19         int nlen = strlen(name);
  20         int len = nlen + 1;
  21
  22         for (p = path; p; p = p->up) {
  23                 if (p->elem_len)
  24                         len += p->elem_len + 1;
  25         }
  26         n = xmalloc(len);
  27         m = n + len - (nlen + 1);
  28         strcpy(m, name);
  29         for (p = path; p; p = p->up) {
  30                 if (p->elem_len) {
  31                         m -= p->elem_len + 1;
  32                         memcpy(m, p->elem, p->elem_len);
  33                         m[p->elem_len] = '/';
  34                 }
  35         }
  36         return n;
  37 }
  38
  39 void add_object(struct object *obj,
  40                 struct object_array *p,
  41                 struct name_path *path,
  42                 const char *name)
  43 {
  44         add_object_array(obj, path_name(path, name), p);
  45 }
  46
  47 static void mark_blob_uninteresting(struct blob *blob)
  48 {
  49         if (blob->object.flags & UNINTERESTING)
  50                 return;
  51         blob->object.flags |= UNINTERESTING;
  52 }
  53
  54 void mark_tree_uninteresting(struct tree *tree)
  55 {
  56         struct tree_desc desc;
  57         struct name_entry entry;
  58         struct object *obj = &tree->object;
  59
  60         if (obj->flags & UNINTERESTING)
  61                 return;
  62         obj->flags |= UNINTERESTING;
  63         if (!has_sha1_file(obj->sha1))
  64                 return;
  65         if (parse_tree(tree) < 0)
  66                 die("bad tree %s", sha1_to_hex(obj->sha1));
  67
  68         init_tree_desc(&desc, tree->buffer, tree->size);
  69         while (tree_entry(&desc, &entry)) {
  70                 if (S_ISDIR(entry.mode))
  71                         mark_tree_uninteresting(lookup_tree(entry.sha1));
  72                 else
  73                         mark_blob_uninteresting(lookup_blob(entry.sha1));
  74         }
  75
  76         /*
  77          * We don't care about the tree any more
  78          * after it has been marked uninteresting.
  79          */
  80         free(tree->buffer);
  81         tree->buffer = NULL;
  82 }
  83
  84 void mark_parents_uninteresting(struct commit *commit)
  85 {
  86         struct commit_list *parents = commit->parents;
  87
  88         while (parents) {
  89                 struct commit *commit = parents->item;
  90                 if (!(commit->object.flags & UNINTERESTING)) {
  91                         commit->object.flags |= UNINTERESTING;
  92
  93                         /*
  94                          * Normally we haven't parsed the parent
  95                          * yet, so we won't have a parent of a parent
  96                          * here. However, it may turn out that we've
  97                          * reached this commit some other way (where it
  98                          * wasn't uninteresting), in which case we need
  99                          * to mark its parents recursively too..
 100                          */
 101                         if (commit->parents)
 102                                 mark_parents_uninteresting(commit);
 103                 }
 104
 105                 /*
 106                  * A missing commit is ok iff its parent is marked
 107                  * uninteresting.
 108                  *
 109                  * We just mark such a thing parsed, so that when
 110                  * it is popped next time around, we won't be trying
 111                  * to parse it and get an error.
 112                  */
 113                 if (!has_sha1_file(commit->object.sha1))
 114                         commit->object.parsed = 1;
 115                 parents = parents->next;
 116         }
 117 }
 118
 119 static void add_pending_object_with_mode(struct rev_info *revs, struct object *obj, const char *name, unsigned mode)
 120 {
 121         if (revs->no_walk && (obj->flags & UNINTERESTING))
 122                 die("object ranges do not make sense when not walking revisions");
 123         if (revs->reflog_info && obj->type == OBJ_COMMIT &&
 124                         add_reflog_for_walk(revs->reflog_info,
 125                                 (struct commit *)obj, name))
 126                 return;
 127         add_object_array_with_mode(obj, name, &revs->pending, mode);
 128 }
 129
 130 void add_pending_object(struct rev_info *revs, struct object *obj, const char *name)
 131 {
 132         add_pending_object_with_mode(revs, obj, name, S_IFINVALID);
 133 }
 134
 135 static struct object *get_reference(struct rev_info *revs, const char *name, const unsigned char *sha1, unsigned int flags)
 136 {
 137         struct object *object;
 138
 139         object = parse_object(sha1);
 140         if (!object)
 141                 die("bad object %s", name);
 142         object->flags |= flags;
 143         return object;
 144 }
 145
 146 static struct commit *handle_commit(struct rev_info *revs, struct object *object, const char *name)
 147 {
 148         unsigned long flags = object->flags;
 149
 150         /*
 151          * Tag object? Look what it points to..
 152          */
 153         while (object->type == OBJ_TAG) {
 154                 struct tag *tag = (struct tag *) object;
 155                 if (revs->tag_objects && !(flags & UNINTERESTING))
 156                         add_pending_object(revs, object, tag->tag);
 157                 object = parse_object(tag->tagged->sha1);
 158                 if (!object)
 159                         die("bad object %s", sha1_to_hex(tag->tagged->sha1));
 160         }
 161
 162         /*
 163          * Commit object? Just return it, we'll do all the complex
 164          * reachability crud.
 165          */
 166         if (object->type == OBJ_COMMIT) {
 167                 struct commit *commit = (struct commit *)object;
 168                 if (parse_commit(commit) < 0)
 169                         die("unable to parse commit %s", name);
 170                 if (flags & UNINTERESTING) {
 171                         commit->object.flags |= UNINTERESTING;
 172                         mark_parents_uninteresting(commit);
 173                         revs->limited = 1;
 174                 }
 175                 return commit;
 176         }
 177
 178         /*
 179          * Tree object? Either mark it uniniteresting, or add it
 180          * to the list of objects to look at later..
 181          */
 182         if (object->type == OBJ_TREE) {
 183                 struct tree *tree = (struct tree *)object;
 184                 if (!revs->tree_objects)
 185                         return NULL;
 186                 if (flags & UNINTERESTING) {
 187                         mark_tree_uninteresting(tree);
 188                         return NULL;
 189                 }
 190                 add_pending_object(revs, object, "");
 191                 return NULL;
 192         }
 193
 194         /*
 195          * Blob object? You know the drill by now..
 196          */
 197         if (object->type == OBJ_BLOB) {
 198                 struct blob *blob = (struct blob *)object;
 199                 if (!revs->blob_objects)
 200                         return NULL;
 201                 if (flags & UNINTERESTING) {
 202                         mark_blob_uninteresting(blob);
 203                         return NULL;
 204                 }
 205                 add_pending_object(revs, object, "");
 206                 return NULL;
 207         }
 208         die("%s is unknown object", name);
 209 }
 210
 211 static int everybody_uninteresting(struct commit_list *orig)
 212 {
 213         struct commit_list *list = orig;
 214         while (list) {
 215                 struct commit *commit = list->item;
 216                 list = list->next;
 217                 if (commit->object.flags & UNINTERESTING)
 218                         continue;
 219                 return 0;
 220         }
 221         return 1;
 222 }
 223
 224 /*
 225  * The goal is to get REV_TREE_NEW as the result only if the
 226  * diff consists of all '+' (and no other changes), and
 227  * REV_TREE_DIFFERENT otherwise (of course if the trees are
 228  * the same we want REV_TREE_SAME).  That means that once we
 229  * get to REV_TREE_DIFFERENT, we do not have to look any further.
 230  */
 231 static int tree_difference = REV_TREE_SAME;
 232
 233 static void file_add_remove(struct diff_options *options,
 234                     int addremove, unsigned mode,
 235                     const unsigned char *sha1,
 236                     const char *base, const char *path)
 237 {
 238         int diff = REV_TREE_DIFFERENT;
 239
 240         /*
 241          * Is it an add of a new file? It means that the old tree
 242          * didn't have it at all, so we will turn "REV_TREE_SAME" ->
 243          * "REV_TREE_NEW", but leave any "REV_TREE_DIFFERENT" alone
 244          * (and if it already was "REV_TREE_NEW", we'll keep it
 245          * "REV_TREE_NEW" of course).
 246          */
 247         if (addremove == '+') {
 248                 diff = tree_difference;
 249                 if (diff != REV_TREE_SAME)
 250                         return;
 251                 diff = REV_TREE_NEW;
 252         }
 253         tree_difference = diff;
 254         if (tree_difference == REV_TREE_DIFFERENT)
 255                 DIFF_OPT_SET(options, HAS_CHANGES);
 256 }
 257
 258 static void file_change(struct diff_options *options,
 259                  unsigned old_mode, unsigned new_mode,
 260                  const unsigned char *old_sha1,
 261                  const unsigned char *new_sha1,
 262                  const char *base, const char *path)
 263 {
 264         tree_difference = REV_TREE_DIFFERENT;
 265         DIFF_OPT_SET(options, HAS_CHANGES);
 266 }
 267
 268 static int rev_compare_tree(struct rev_info *revs, struct tree *t1, struct tree *t2)
 269 {
 270         if (!t1)
 271                 return REV_TREE_NEW;
 272         if (!t2)
 273                 return REV_TREE_DIFFERENT;
 274         tree_difference = REV_TREE_SAME;
 275         DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
 276         if (diff_tree_sha1(t1->object.sha1, t2->object.sha1, "",
 277                            &revs->pruning) < 0)
 278                 return REV_TREE_DIFFERENT;
 279         return tree_difference;
 280 }
 281
 282 static int rev_same_tree_as_empty(struct rev_info *revs, struct tree *t1)
 283 {
 284         int retval;
 285         void *tree;
 286         unsigned long size;
 287         struct tree_desc empty, real;
 288
 289         if (!t1)
 290                 return 0;
 291
 292         tree = read_object_with_reference(t1->object.sha1, tree_type, &size, NULL);
 293         if (!tree)
 294                 return 0;
 295         init_tree_desc(&real, tree, size);
 296         init_tree_desc(&empty, "", 0);
 297
 298         tree_difference = REV_TREE_SAME;
 299         DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
 300         retval = diff_tree(&empty, &real, "", &revs->pruning);
 301         free(tree);
 302
 303         return retval >= 0 && (tree_difference == REV_TREE_SAME);
 304 }
 305
 306 static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
 307 {
 308         struct commit_list **pp, *parent;
 309         int tree_changed = 0, tree_same = 0;
 310
 311         /*
 312          * If we don't do pruning, everything is interesting
 313          */
 314         if (!revs->prune)
 315                 return;
 316
 317         if (!commit->tree)
 318                 return;
 319
 320         if (!commit->parents) {
 321                 if (rev_same_tree_as_empty(revs, commit->tree))
 322                         commit->object.flags |= TREESAME;
 323                 return;
 324         }
 325
 326         /*
 327          * Normal non-merge commit? If we don't want to make the
 328          * history dense, we consider it always to be a change..
 329          */
 330         if (!revs->dense && !commit->parents->next)
 331                 return;
 332
 333         pp = &commit->parents;
 334         while ((parent = *pp) != NULL) {
 335                 struct commit *p = parent->item;
 336
 337                 if (parse_commit(p) < 0)
 338                         die("cannot simplify commit %s (because of %s)",
 339                             sha1_to_hex(commit->object.sha1),
 340                             sha1_to_hex(p->object.sha1));
 341                 switch (rev_compare_tree(revs, p->tree, commit->tree)) {
 342                 case REV_TREE_SAME:
 343                         tree_same = 1;
 344                         if (!revs->simplify_history || (p->object.flags & UNINTERESTING)) {
 345                                 /* Even if a merge with an uninteresting
 346                                  * side branch brought the entire change
 347                                  * we are interested in, we do not want
 348                                  * to lose the other branches of this
 349                                  * merge, so we just keep going.
 350                                  */
 351                                 pp = &parent->next;
 352                                 continue;
 353                         }
 354                         parent->next = NULL;
 355                         commit->parents = parent;
 356                         commit->object.flags |= TREESAME;
 357                         return;
 358
 359                 case REV_TREE_NEW:
 360                         if (revs->remove_empty_trees &&
 361                             rev_same_tree_as_empty(revs, p->tree)) {
 362                                 /* We are adding all the specified
 363                                  * paths from this parent, so the
 364                                  * history beyond this parent is not
 365                                  * interesting.  Remove its parents
 366                                  * (they are grandparents for us).
 367                                  * IOW, we pretend this parent is a
 368                                  * "root" commit.
 369                                  */
 370                                 if (parse_commit(p) < 0)
 371                                         die("cannot simplify commit %s (invalid %s)",
 372                                             sha1_to_hex(commit->object.sha1),
 373                                             sha1_to_hex(p->object.sha1));
 374                                 p->parents = NULL;
 375                         }
 376                 /* fallthrough */
 377                 case REV_TREE_DIFFERENT:
 378                         tree_changed = 1;
 379                         pp = &parent->next;
 380                         continue;
 381                 }
 382                 die("bad tree compare for commit %s", sha1_to_hex(commit->object.sha1));
 383         }
 384         if (tree_changed && !tree_same)
 385                 return;
 386         commit->object.flags |= TREESAME;
 387 }
 388
 389 static int add_parents_to_list(struct rev_info *revs, struct commit *commit, struct commit_list **list)
 390 {
 391         struct commit_list *parent = commit->parents;
 392         unsigned left_flag;
 393         int add, rest;
 394
 395         if (commit->object.flags & ADDED)
 396                 return 0;
 397         commit->object.flags |= ADDED;
 398
 399         /*
 400          * If the commit is uninteresting, don't try to
 401          * prune parents - we want the maximal uninteresting
 402          * set.
 403          *
 404          * Normally we haven't parsed the parent
 405          * yet, so we won't have a parent of a parent
 406          * here. However, it may turn out that we've
 407          * reached this commit some other way (where it
 408          * wasn't uninteresting), in which case we need
 409          * to mark its parents recursively too..
 410          */
 411         if (commit->object.flags & UNINTERESTING) {
 412                 while (parent) {
 413                         struct commit *p = parent->item;
 414                         parent = parent->next;
 415                         if (parse_commit(p) < 0)
 416                                 return -1;
 417                         p->object.flags |= UNINTERESTING;
 418                         if (p->parents)
 419                                 mark_parents_uninteresting(p);
 420                         if (p->object.flags & SEEN)
 421                                 continue;
 422                         p->object.flags |= SEEN;
 423                         insert_by_date(p, list);
 424                 }
 425                 return 0;
 426         }
 427
 428         /*
 429          * Ok, the commit wasn't uninteresting. Try to
 430          * simplify the commit history and find the parent
 431          * that has no differences in the path set if one exists.
 432          */
 433         try_to_simplify_commit(revs, commit);
 434
 435         if (revs->no_walk)
 436                 return 0;
 437
 438         left_flag = (commit->object.flags & SYMMETRIC_LEFT);
 439
 440         rest = !revs->first_parent_only;
 441         for (parent = commit->parents, add = 1; parent; add = rest) {
 442                 struct commit *p = parent->item;
 443
 444                 parent = parent->next;
 445                 if (parse_commit(p) < 0)
 446                         return -1;
 447                 p->object.flags |= left_flag;
 448                 if (p->object.flags & SEEN)
 449                         continue;
 450                 p->object.flags |= SEEN;
 451                 if (add)
 452                         insert_by_date(p, list);
 453         }
 454         return 0;
 455 }
 456
 457 static void cherry_pick_list(struct commit_list *list, struct rev_info *revs)
 458 {
 459         struct commit_list *p;
 460         int left_count = 0, right_count = 0;
 461         int left_first;
 462         struct patch_ids ids;
 463
 464         /* First count the commits on the left and on the right */
 465         for (p = list; p; p = p->next) {
 466                 struct commit *commit = p->item;
 467                 unsigned flags = commit->object.flags;
 468                 if (flags & BOUNDARY)
 469                         ;
 470                 else if (flags & SYMMETRIC_LEFT)
 471                         left_count++;
 472                 else
 473                         right_count++;
 474         }
 475
 476         left_first = left_count < right_count;
 477         init_patch_ids(&ids);
 478         if (revs->diffopt.nr_paths) {
 479                 ids.diffopts.nr_paths = revs->diffopt.nr_paths;
 480                 ids.diffopts.paths = revs->diffopt.paths;
 481                 ids.diffopts.pathlens = revs->diffopt.pathlens;
 482         }
 483
 484         /* Compute patch-ids for one side */
 485         for (p = list; p; p = p->next) {
 486                 struct commit *commit = p->item;
 487                 unsigned flags = commit->object.flags;
 488
 489                 if (flags & BOUNDARY)
 490                         continue;
 491                 /*
 492                  * If we have fewer left, left_first is set and we omit
 493                  * commits on the right branch in this loop.  If we have
 494                  * fewer right, we skip the left ones.
 495                  */
 496                 if (left_first != !!(flags & SYMMETRIC_LEFT))
 497                         continue;
 498                 commit->util = add_commit_patch_id(commit, &ids);
 499         }
 500
 501         /* Check the other side */
 502         for (p = list; p; p = p->next) {
 503                 struct commit *commit = p->item;
 504                 struct patch_id *id;
 505                 unsigned flags = commit->object.flags;
 506
 507                 if (flags & BOUNDARY)
 508                         continue;
 509                 /*
 510                  * If we have fewer left, left_first is set and we omit
 511                  * commits on the left branch in this loop.
 512                  */
 513                 if (left_first == !!(flags & SYMMETRIC_LEFT))
 514                         continue;
 515
 516                 /*
 517                  * Have we seen the same patch id?
 518                  */
 519                 id = has_commit_patch_id(commit, &ids);
 520                 if (!id)
 521                         continue;
 522                 id->seen = 1;
 523                 commit->object.flags |= SHOWN;
 524         }
 525
 526         /* Now check the original side for seen ones */
 527         for (p = list; p; p = p->next) {
 528                 struct commit *commit = p->item;
 529                 struct patch_id *ent;
 530
 531                 ent = commit->util;
 532                 if (!ent)
 533                         continue;
 534                 if (ent->seen)
 535                         commit->object.flags |= SHOWN;
 536                 commit->util = NULL;
 537         }
 538
 539         free_patch_ids(&ids);
 540 }
 541
 542 static int limit_list(struct rev_info *revs)
 543 {
 544         struct commit_list *list = revs->commits;
 545         struct commit_list *newlist = NULL;
 546         struct commit_list **p = &newlist;
 547
 548         while (list) {
 549                 struct commit_list *entry = list;
 550                 struct commit *commit = list->item;
 551                 struct object *obj = &commit->object;
 552                 show_early_output_fn_t show;
 553
 554                 list = list->next;
 555                 free(entry);
 556
 557                 if (revs->max_age != -1 && (commit->date < revs->max_age))
 558                         obj->flags |= UNINTERESTING;
 559                 if (add_parents_to_list(revs, commit, &list) < 0)
 560                         return -1;
 561                 if (obj->flags & UNINTERESTING) {
 562                         mark_parents_uninteresting(commit);
 563                         if (everybody_uninteresting(list))
 564                                 break;
 565                         continue;
 566                 }
 567                 if (revs->min_age != -1 && (commit->date > revs->min_age))
 568                         continue;
 569                 p = &commit_list_insert(commit, p)->next;
 570
 571                 show = show_early_output;
 572                 if (!show)
 573                         continue;
 574
 575                 show(revs, newlist);
 576                 show_early_output = NULL;
 577         }
 578         if (revs->cherry_pick)
 579                 cherry_pick_list(newlist, revs);
 580
 581         revs->commits = newlist;
 582         return 0;
 583 }
 584
 585 struct all_refs_cb {
 586         int all_flags;
 587         int warned_bad_reflog;
 588         struct rev_info *all_revs;
 589         const char *name_for_errormsg;
 590 };
 591
 592 static int handle_one_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
 593 {
 594         struct all_refs_cb *cb = cb_data;
 595         struct object *object = get_reference(cb->all_revs, path, sha1,
 596                                               cb->all_flags);
 597         add_pending_object(cb->all_revs, object, path);
 598         return 0;
 599 }
 600
 601 static void handle_all(struct rev_info *revs, unsigned flags)
 602 {
 603         struct all_refs_cb cb;
 604         cb.all_revs = revs;
 605         cb.all_flags = flags;
 606         for_each_ref(handle_one_ref, &cb);
 607 }
 608
 609 static void handle_one_reflog_commit(unsigned char *sha1, void *cb_data)
 610 {
 611         struct all_refs_cb *cb = cb_data;
 612         if (!is_null_sha1(sha1)) {
 613                 struct object *o = parse_object(sha1);
 614                 if (o) {
 615                         o->flags |= cb->all_flags;
 616                         add_pending_object(cb->all_revs, o, "");
 617                 }
 618                 else if (!cb->warned_bad_reflog) {
 619                         warning("reflog of '%s' references pruned commits",
 620                                 cb->name_for_errormsg);
 621                         cb->warned_bad_reflog = 1;
 622                 }
 623         }
 624 }
 625
 626 static int handle_one_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
 627                 const char *email, unsigned long timestamp, int tz,
 628                 const char *message, void *cb_data)
 629 {
 630         handle_one_reflog_commit(osha1, cb_data);
 631         handle_one_reflog_commit(nsha1, cb_data);
 632         return 0;
 633 }
 634
 635 static int handle_one_reflog(const char *path, const unsigned char *sha1, int flag, void *cb_data)
 636 {
 637         struct all_refs_cb *cb = cb_data;
 638         cb->warned_bad_reflog = 0;
 639         cb->name_for_errormsg = path;
 640         for_each_reflog_ent(path, handle_one_reflog_ent, cb_data);
 641         return 0;
 642 }
 643
 644 static void handle_reflog(struct rev_info *revs, unsigned flags)
 645 {
 646         struct all_refs_cb cb;
 647         cb.all_revs = revs;
 648         cb.all_flags = flags;
 649         for_each_reflog(handle_one_reflog, &cb);
 650 }
 651
 652 static int add_parents_only(struct rev_info *revs, const char *arg, int flags)
 653 {
 654         unsigned char sha1[20];
 655         struct object *it;
 656         struct commit *commit;
 657         struct commit_list *parents;
 658
 659         if (*arg == '^') {
 660                 flags ^= UNINTERESTING;
 661                 arg++;
 662         }
 663         if (get_sha1(arg, sha1))
 664                 return 0;
 665         while (1) {
 666                 it = get_reference(revs, arg, sha1, 0);
 667                 if (it->type != OBJ_TAG)
 668                         break;
 669                 hashcpy(sha1, ((struct tag*)it)->tagged->sha1);
 670         }
 671         if (it->type != OBJ_COMMIT)
 672                 return 0;
 673         commit = (struct commit *)it;
 674         for (parents = commit->parents; parents; parents = parents->next) {
 675                 it = &parents->item->object;
 676                 it->flags |= flags;
 677                 add_pending_object(revs, it, arg);
 678         }
 679         return 1;
 680 }
 681
 682 void init_revisions(struct rev_info *revs, const char *prefix)
 683 {
 684         memset(revs, 0, sizeof(*revs));
 685
 686         revs->abbrev = DEFAULT_ABBREV;
 687         revs->ignore_merges = 1;
 688         revs->simplify_history = 1;
 689         DIFF_OPT_SET(&revs->pruning, RECURSIVE);
 690         DIFF_OPT_SET(&revs->pruning, QUIET);
 691         revs->pruning.add_remove = file_add_remove;
 692         revs->pruning.change = file_change;
 693         revs->lifo = 1;
 694         revs->dense = 1;
 695         revs->prefix = prefix;
 696         revs->max_age = -1;
 697         revs->min_age = -1;
 698         revs->skip_count = -1;
 699         revs->max_count = -1;
 700
 701         revs->commit_format = CMIT_FMT_DEFAULT;
 702
 703         diff_setup(&revs->diffopt);
 704 }
 705
 706 static void add_pending_commit_list(struct rev_info *revs,
 707                                     struct commit_list *commit_list,
 708                                     unsigned int flags)
 709 {
 710         while (commit_list) {
 711                 struct object *object = &commit_list->item->object;
 712                 object->flags |= flags;
 713                 add_pending_object(revs, object, sha1_to_hex(object->sha1));
 714                 commit_list = commit_list->next;
 715         }
 716 }
 717
 718 static void prepare_show_merge(struct rev_info *revs)
 719 {
 720         struct commit_list *bases;
 721         struct commit *head, *other;
 722         unsigned char sha1[20];
 723         const char **prune = NULL;
 724         int i, prune_num = 1; /* counting terminating NULL */
 725
 726         if (get_sha1("HEAD", sha1) || !(head = lookup_commit(sha1)))
 727                 die("--merge without HEAD?");
 728         if (get_sha1("MERGE_HEAD", sha1) || !(other = lookup_commit(sha1)))
 729                 die("--merge without MERGE_HEAD?");
 730         add_pending_object(revs, &head->object, "HEAD");
 731         add_pending_object(revs, &other->object, "MERGE_HEAD");
 732         bases = get_merge_bases(head, other, 1);
 733         while (bases) {
 734                 struct commit *it = bases->item;
 735                 struct commit_list *n = bases->next;
 736                 free(bases);
 737                 bases = n;
 738                 it->object.flags |= UNINTERESTING;
 739                 add_pending_object(revs, &it->object, "(merge-base)");
 740         }
 741
 742         if (!active_nr)
 743                 read_cache();
 744         for (i = 0; i < active_nr; i++) {
 745                 struct cache_entry *ce = active_cache[i];
 746                 if (!ce_stage(ce))
 747                         continue;
 748                 if (ce_path_match(ce, revs->prune_data)) {
 749                         prune_num++;
 750                         prune = xrealloc(prune, sizeof(*prune) * prune_num);
 751                         prune[prune_num-2] = ce->name;
 752                         prune[prune_num-1] = NULL;
 753                 }
 754                 while ((i+1 < active_nr) &&
 755                        ce_same_name(ce, active_cache[i+1]))
 756                         i++;
 757         }
 758         revs->prune_data = prune;
 759 }
 760
 761 int handle_revision_arg(const char *arg, struct rev_info *revs,
 762                         int flags,
 763                         int cant_be_filename)
 764 {
 765         unsigned mode;
 766         char *dotdot;
 767         struct object *object;
 768         unsigned char sha1[20];
 769         int local_flags;
 770
 771         dotdot = strstr(arg, "..");
 772         if (dotdot) {
 773                 unsigned char from_sha1[20];
 774                 const char *next = dotdot + 2;
 775                 const char *this = arg;
 776                 int symmetric = *next == '.';
 777                 unsigned int flags_exclude = flags ^ UNINTERESTING;
 778
 779                 *dotdot = 0;
 780                 next += symmetric;
 781
 782                 if (!*next)
 783                         next = "HEAD";
 784                 if (dotdot == arg)
 785                         this = "HEAD";
 786                 if (!get_sha1(this, from_sha1) &&
 787                     !get_sha1(next, sha1)) {
 788                         struct commit *a, *b;
 789                         struct commit_list *exclude;
 790
 791                         a = lookup_commit_reference(from_sha1);
 792                         b = lookup_commit_reference(sha1);
 793                         if (!a || !b) {
 794                                 die(symmetric ?
 795                                     "Invalid symmetric difference expression %s...%s" :
 796                                     "Invalid revision range %s..%s",
 797                                     arg, next);
 798                         }
 799
 800                         if (!cant_be_filename) {
 801                                 *dotdot = '.';
 802                                 verify_non_filename(revs->prefix, arg);
 803                         }
 804
 805                         if (symmetric) {
 806                                 exclude = get_merge_bases(a, b, 1);
 807                                 add_pending_commit_list(revs, exclude,
 808                                                         flags_exclude);
 809                                 free_commit_list(exclude);
 810                                 a->object.flags |= flags | SYMMETRIC_LEFT;
 811                         } else
 812                                 a->object.flags |= flags_exclude;
 813                         b->object.flags |= flags;
 814                         add_pending_object(revs, &a->object, this);
 815                         add_pending_object(revs, &b->object, next);
 816                         return 0;
 817                 }
 818                 *dotdot = '.';
 819         }
 820         dotdot = strstr(arg, "^@");
 821         if (dotdot && !dotdot[2]) {
 822                 *dotdot = 0;
 823                 if (add_parents_only(revs, arg, flags))
 824                         return 0;
 825                 *dotdot = '^';
 826         }
 827         dotdot = strstr(arg, "^!");
 828         if (dotdot && !dotdot[2]) {
 829                 *dotdot = 0;
 830                 if (!add_parents_only(revs, arg, flags ^ UNINTERESTING))
 831                         *dotdot = '^';
 832         }
 833
 834         local_flags = 0;
 835         if (*arg == '^') {
 836                 local_flags = UNINTERESTING;
 837                 arg++;
 838         }
 839         if (get_sha1_with_mode(arg, sha1, &mode))
 840                 return -1;
 841         if (!cant_be_filename)
 842                 verify_non_filename(revs->prefix, arg);
 843         object = get_reference(revs, arg, sha1, flags ^ local_flags);
 844         add_pending_object_with_mode(revs, object, arg, mode);
 845         return 0;
 846 }
 847
 848 static void add_grep(struct rev_info *revs, const char *ptn, enum grep_pat_token what)
 849 {
 850         if (!revs->grep_filter) {
 851                 struct grep_opt *opt = xcalloc(1, sizeof(*opt));
 852                 opt->status_only = 1;
 853                 opt->pattern_tail = &(opt->pattern_list);
 854                 opt->regflags = REG_NEWLINE;
 855                 revs->grep_filter = opt;
 856         }
 857         append_grep_pattern(revs->grep_filter, ptn,
 858                             "command line", 0, what);
 859 }
 860
 861 static void add_header_grep(struct rev_info *revs, const char *field, const char *pattern)
 862 {
 863         char *pat;
 864         const char *prefix;
 865         int patlen, fldlen;
 866
 867         fldlen = strlen(field);
 868         patlen = strlen(pattern);
 869         pat = xmalloc(patlen + fldlen + 10);
 870         prefix = ".*";
 871         if (*pattern == '^') {
 872                 prefix = "";
 873                 pattern++;
 874         }
 875         sprintf(pat, "^%s %s%s", field, prefix, pattern);
 876         add_grep(revs, pat, GREP_PATTERN_HEAD);
 877 }
 878
 879 static void add_message_grep(struct rev_info *revs, const char *pattern)
 880 {
 881         add_grep(revs, pattern, GREP_PATTERN_BODY);
 882 }
 883
 884 static void add_ignore_packed(struct rev_info *revs, const char *name)
 885 {
 886         int num = ++revs->num_ignore_packed;
 887
 888         revs->ignore_packed = xrealloc(revs->ignore_packed,
 889                                        sizeof(const char **) * (num + 1));
 890         revs->ignore_packed[num-1] = name;
 891         revs->ignore_packed[num] = NULL;
 892 }
 893
 894 /*
 895  * Parse revision information, filling in the "rev_info" structure,
 896  * and removing the used arguments from the argument list.
 897  *
 898  * Returns the number of arguments left that weren't recognized
 899  * (which are also moved to the head of the argument list)
 900  */
 901 int setup_revisions(int argc, const char **argv, struct rev_info *revs, const char *def)
 902 {
 903         int i, flags, seen_dashdash, show_merge;
 904         const char **unrecognized = argv + 1;
 905         int left = 1;
 906         int all_match = 0;
 907         int regflags = 0;
 908
 909         /* First, search for "--" */
 910         seen_dashdash = 0;
 911         for (i = 1; i < argc; i++) {
 912                 const char *arg = argv[i];
 913                 if (strcmp(arg, "--"))
 914                         continue;
 915                 argv[i] = NULL;
 916                 argc = i;
 917                 if (argv[i + 1])
 918                         revs->prune_data = get_pathspec(revs->prefix, argv + i + 1);
 919                 seen_dashdash = 1;
 920                 break;
 921         }
 922
 923         flags = show_merge = 0;
 924         for (i = 1; i < argc; i++) {
 925                 const char *arg = argv[i];
 926                 if (*arg == '-') {
 927                         int opts;
 928                         if (!prefixcmp(arg, "--max-count=")) {
 929                                 revs->max_count = atoi(arg + 12);
 930                                 continue;
 931                         }
 932                         if (!prefixcmp(arg, "--skip=")) {
 933                                 revs->skip_count = atoi(arg + 7);
 934                                 continue;
 935                         }
 936                         /* accept -<digit>, like traditional "head" */
 937                         if ((*arg == '-') && isdigit(arg[1])) {
 938                                 revs->max_count = atoi(arg + 1);
 939                                 continue;
 940                         }
 941                         if (!strcmp(arg, "-n")) {
 942                                 if (argc <= i + 1)
 943                                         die("-n requires an argument");
 944                                 revs->max_count = atoi(argv[++i]);
 945                                 continue;
 946                         }
 947                         if (!prefixcmp(arg, "-n")) {
 948                                 revs->max_count = atoi(arg + 2);
 949                                 continue;
 950                         }
 951                         if (!prefixcmp(arg, "--max-age=")) {
 952                                 revs->max_age = atoi(arg + 10);
 953                                 continue;
 954                         }
 955                         if (!prefixcmp(arg, "--since=")) {
 956                                 revs->max_age = approxidate(arg + 8);
 957                                 continue;
 958                         }
 959                         if (!prefixcmp(arg, "--after=")) {
 960                                 revs->max_age = approxidate(arg + 8);
 961                                 continue;
 962                         }
 963                         if (!prefixcmp(arg, "--min-age=")) {
 964                                 revs->min_age = atoi(arg + 10);
 965                                 continue;
 966                         }
 967                         if (!prefixcmp(arg, "--before=")) {
 968                                 revs->min_age = approxidate(arg + 9);
 969                                 continue;
 970                         }
 971                         if (!prefixcmp(arg, "--until=")) {
 972                                 revs->min_age = approxidate(arg + 8);
 973                                 continue;
 974                         }
 975                         if (!strcmp(arg, "--all")) {
 976                                 handle_all(revs, flags);
 977                                 continue;
 978                         }
 979                         if (!strcmp(arg, "--first-parent")) {
 980                                 revs->first_parent_only = 1;
 981                                 continue;
 982                         }
 983                         if (!strcmp(arg, "--reflog")) {
 984                                 handle_reflog(revs, flags);
 985                                 continue;
 986                         }
 987                         if (!strcmp(arg, "-g") ||
 988                                         !strcmp(arg, "--walk-reflogs")) {
 989                                 init_reflog_walk(&revs->reflog_info);
 990                                 continue;
 991                         }
 992                         if (!strcmp(arg, "--not")) {
 993                                 flags ^= UNINTERESTING;
 994                                 continue;
 995                         }
 996                         if (!strcmp(arg, "--default")) {
 997                                 if (++i >= argc)
 998                                         die("bad --default argument");
 999                                 def = argv[i];
1000                                 continue;
1001                         }
1002                         if (!strcmp(arg, "--merge")) {
1003                                 show_merge = 1;
1004                                 continue;
1005                         }
1006                         if (!strcmp(arg, "--topo-order")) {
1007                                 revs->topo_order = 1;
1008                                 continue;
1009                         }
1010                         if (!strcmp(arg, "--date-order")) {
1011                                 revs->lifo = 0;
1012                                 revs->topo_order = 1;
1013                                 continue;
1014                         }
1015                         if (!prefixcmp(arg, "--early-output")) {
1016                                 int count = 100;
1017                                 switch (arg[14]) {
1018                                 case '=':
1019                                         count = atoi(arg+15);
1020                                         /* Fallthrough */
1021                                 case 0:
1022                                         revs->topo_order = 1;
1023                                         revs->early_output = count;
1024                                         continue;
1025                                 }
1026                         }
1027                         if (!strcmp(arg, "--parents")) {
1028                                 revs->parents = 1;
1029                                 continue;
1030                         }
1031                         if (!strcmp(arg, "--dense")) {
1032                                 revs->dense = 1;
1033                                 continue;
1034                         }
1035                         if (!strcmp(arg, "--sparse")) {
1036                                 revs->dense = 0;
1037                                 continue;
1038                         }
1039                         if (!strcmp(arg, "--remove-empty")) {
1040                                 revs->remove_empty_trees = 1;
1041                                 continue;
1042                         }
1043                         if (!strcmp(arg, "--no-merges")) {
1044                                 revs->no_merges = 1;
1045                                 continue;
1046                         }
1047                         if (!strcmp(arg, "--boundary")) {
1048                                 revs->boundary = 1;
1049                                 continue;
1050                         }
1051                         if (!strcmp(arg, "--left-right")) {
1052                                 revs->left_right = 1;
1053                                 continue;
1054                         }
1055                         if (!strcmp(arg, "--cherry-pick")) {
1056                                 revs->cherry_pick = 1;
1057                                 revs->limited = 1;
1058                                 continue;
1059                         }
1060                         if (!strcmp(arg, "--objects")) {
1061                                 revs->tag_objects = 1;
1062                                 revs->tree_objects = 1;
1063                                 revs->blob_objects = 1;
1064                                 continue;
1065                         }
1066                         if (!strcmp(arg, "--objects-edge")) {
1067                                 revs->tag_objects = 1;
1068                                 revs->tree_objects = 1;
1069                                 revs->blob_objects = 1;
1070                                 revs->edge_hint = 1;
1071                                 continue;
1072                         }
1073                         if (!strcmp(arg, "--unpacked")) {
1074                                 revs->unpacked = 1;
1075                                 free(revs->ignore_packed);
1076                                 revs->ignore_packed = NULL;
1077                                 revs->num_ignore_packed = 0;
1078                                 continue;
1079                         }
1080                         if (!prefixcmp(arg, "--unpacked=")) {
1081                                 revs->unpacked = 1;
1082                                 add_ignore_packed(revs, arg+11);
1083                                 continue;
1084                         }
1085                         if (!strcmp(arg, "-r")) {
1086                                 revs->diff = 1;
1087                                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1088                                 continue;
1089                         }
1090                         if (!strcmp(arg, "-t")) {
1091                                 revs->diff = 1;
1092                                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1093                                 DIFF_OPT_SET(&revs->diffopt, TREE_IN_RECURSIVE);
1094                                 continue;
1095                         }
1096                         if (!strcmp(arg, "-m")) {
1097                                 revs->ignore_merges = 0;
1098                                 continue;
1099                         }
1100                         if (!strcmp(arg, "-c")) {
1101                                 revs->diff = 1;
1102                                 revs->dense_combined_merges = 0;
1103                                 revs->combine_merges = 1;
1104                                 continue;
1105                         }
1106                         if (!strcmp(arg, "--cc")) {
1107                                 revs->diff = 1;
1108                                 revs->dense_combined_merges = 1;
1109                                 revs->combine_merges = 1;
1110                                 continue;
1111                         }
1112                         if (!strcmp(arg, "-v")) {
1113                                 revs->verbose_header = 1;
1114                                 continue;
1115                         }
1116                         if (!prefixcmp(arg, "--pretty")) {
1117                                 revs->verbose_header = 1;
1118                                 revs->commit_format = get_commit_format(arg+8);
1119                                 continue;
1120                         }
1121                         if (!strcmp(arg, "--root")) {
1122                                 revs->show_root_diff = 1;
1123                                 continue;
1124                         }
1125                         if (!strcmp(arg, "--no-commit-id")) {
1126                                 revs->no_commit_id = 1;
1127                                 continue;
1128                         }
1129                         if (!strcmp(arg, "--always")) {
1130                                 revs->always_show_header = 1;
1131                                 continue;
1132                         }
1133                         if (!strcmp(arg, "--no-abbrev")) {
1134                                 revs->abbrev = 0;
1135                                 continue;
1136                         }
1137                         if (!strcmp(arg, "--abbrev")) {
1138                                 revs->abbrev = DEFAULT_ABBREV;
1139                                 continue;
1140                         }
1141                         if (!prefixcmp(arg, "--abbrev=")) {
1142                                 revs->abbrev = strtoul(arg + 9, NULL, 10);
1143                                 if (revs->abbrev < MINIMUM_ABBREV)
1144                                         revs->abbrev = MINIMUM_ABBREV;
1145                                 else if (revs->abbrev > 40)
1146                                         revs->abbrev = 40;
1147                                 continue;
1148                         }
1149                         if (!strcmp(arg, "--abbrev-commit")) {
1150                                 revs->abbrev_commit = 1;
1151                                 continue;
1152                         }
1153                         if (!strcmp(arg, "--full-diff")) {
1154                                 revs->diff = 1;
1155                                 revs->full_diff = 1;
1156                                 continue;
1157                         }
1158                         if (!strcmp(arg, "--full-history")) {
1159                                 revs->simplify_history = 0;
1160                                 continue;
1161                         }
1162                         if (!strcmp(arg, "--relative-date")) {
1163                                 revs->date_mode = DATE_RELATIVE;
1164                                 continue;
1165                         }
1166                         if (!strncmp(arg, "--date=", 7)) {
1167                                 revs->date_mode = parse_date_format(arg + 7);
1168                                 continue;
1169                         }
1170                         if (!strcmp(arg, "--log-size")) {
1171                                 revs->show_log_size = 1;
1172                                 continue;
1173                         }
1174
1175                         /*
1176                          * Grepping the commit log
1177                          */
1178                         if (!prefixcmp(arg, "--author=")) {
1179                                 add_header_grep(revs, "author", arg+9);
1180                                 continue;
1181                         }
1182                         if (!prefixcmp(arg, "--committer=")) {
1183                                 add_header_grep(revs, "committer", arg+12);
1184                                 continue;
1185                         }
1186                         if (!prefixcmp(arg, "--grep=")) {
1187                                 add_message_grep(revs, arg+7);
1188                                 continue;
1189                         }
1190                         if (!strcmp(arg, "--extended-regexp") ||
1191                             !strcmp(arg, "-E")) {
1192                                 regflags |= REG_EXTENDED;
1193                                 continue;
1194                         }
1195                         if (!strcmp(arg, "--regexp-ignore-case") ||
1196                             !strcmp(arg, "-i")) {
1197                                 regflags |= REG_ICASE;
1198                                 continue;
1199                         }
1200                         if (!strcmp(arg, "--all-match")) {
1201                                 all_match = 1;
1202                                 continue;
1203                         }
1204                         if (!prefixcmp(arg, "--encoding=")) {
1205                                 arg += 11;
1206                                 if (strcmp(arg, "none"))
1207                                         git_log_output_encoding = xstrdup(arg);
1208                                 else
1209                                         git_log_output_encoding = "";
1210                                 continue;
1211                         }
1212                         if (!strcmp(arg, "--reverse")) {
1213                                 revs->reverse ^= 1;
1214                                 continue;
1215                         }
1216                         if (!strcmp(arg, "--no-walk")) {
1217                                 revs->no_walk = 1;
1218                                 continue;
1219                         }
1220                         if (!strcmp(arg, "--do-walk")) {
1221                                 revs->no_walk = 0;
1222                                 continue;
1223                         }
1224
1225                         opts = diff_opt_parse(&revs->diffopt, argv+i, argc-i);
1226                         if (opts > 0) {
1227                                 i += opts - 1;
1228                                 continue;
1229                         }
1230                         *unrecognized++ = arg;
1231                         left++;
1232                         continue;
1233                 }
1234
1235                 if (handle_revision_arg(arg, revs, flags, seen_dashdash)) {
1236                         int j;
1237                         if (seen_dashdash || *arg == '^')
1238                                 die("bad revision '%s'", arg);
1239
1240                         /* If we didn't have a "--":
1241                          * (1) all filenames must exist;
1242                          * (2) all rev-args must not be interpretable
1243                          *     as a valid filename.
1244                          * but the latter we have checked in the main loop.
1245                          */
1246                         for (j = i; j < argc; j++)
1247                                 verify_filename(revs->prefix, argv[j]);
1248
1249                         revs->prune_data = get_pathspec(revs->prefix,
1250                                                         argv + i);
1251                         break;
1252                 }
1253         }
1254
1255         if (revs->grep_filter)
1256                 revs->grep_filter->regflags |= regflags;
1257
1258         if (show_merge)
1259                 prepare_show_merge(revs);
1260         if (def && !revs->pending.nr) {
1261                 unsigned char sha1[20];
1262                 struct object *object;
1263                 unsigned mode;
1264                 if (get_sha1_with_mode(def, sha1, &mode))
1265                         die("bad default revision '%s'", def);
1266                 object = get_reference(revs, def, sha1, 0);
1267                 add_pending_object_with_mode(revs, object, def, mode);
1268         }
1269
1270         /* Did the user ask for any diff output? Run the diff! */
1271         if (revs->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT)
1272                 revs->diff = 1;
1273
1274         /* Pickaxe and rename following needs diffs */
1275         if (revs->diffopt.pickaxe || DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1276                 revs->diff = 1;
1277
1278         if (revs->topo_order)
1279                 revs->limited = 1;
1280
1281         if (revs->prune_data) {
1282                 diff_tree_setup_paths(revs->prune_data, &revs->pruning);
1283                 /* Can't prune commits with rename following: the paths change.. */
1284                 if (!DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1285                         revs->prune = 1;
1286                 if (!revs->full_diff)
1287                         diff_tree_setup_paths(revs->prune_data, &revs->diffopt);
1288         }
1289         if (revs->combine_merges) {
1290                 revs->ignore_merges = 0;
1291                 if (revs->dense_combined_merges && !revs->diffopt.output_format)
1292                         revs->diffopt.output_format = DIFF_FORMAT_PATCH;
1293         }
1294         revs->diffopt.abbrev = revs->abbrev;
1295         if (diff_setup_done(&revs->diffopt) < 0)
1296                 die("diff_setup_done failed");
1297
1298         if (revs->grep_filter) {
1299                 revs->grep_filter->all_match = all_match;
1300                 compile_grep_patterns(revs->grep_filter);
1301         }
1302
1303         if (revs->reverse && revs->reflog_info)
1304                 die("cannot combine --reverse with --walk-reflogs");
1305
1306         return left;
1307 }
1308
1309 int prepare_revision_walk(struct rev_info *revs)
1310 {
1311         int nr = revs->pending.nr;
1312         struct object_array_entry *e, *list;
1313
1314         e = list = revs->pending.objects;
1315         revs->pending.nr = 0;
1316         revs->pending.alloc = 0;
1317         revs->pending.objects = NULL;
1318         while (--nr >= 0) {
1319                 struct commit *commit = handle_commit(revs, e->item, e->name);
1320                 if (commit) {
1321                         if (!(commit->object.flags & SEEN)) {
1322                                 commit->object.flags |= SEEN;
1323                                 insert_by_date(commit, &revs->commits);
1324                         }
1325                 }
1326                 e++;
1327         }
1328         free(list);
1329
1330         if (revs->no_walk)
1331                 return 0;
1332         if (revs->limited)
1333                 if (limit_list(revs) < 0)
1334                         return -1;
1335         if (revs->topo_order)
1336                 sort_in_topological_order(&revs->commits, revs->lifo);
1337         return 0;
1338 }
1339
1340 enum rewrite_result {
1341         rewrite_one_ok,
1342         rewrite_one_noparents,
1343         rewrite_one_error,
1344 };
1345
1346 static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp)
1347 {
1348         for (;;) {
1349                 struct commit *p = *pp;
1350                 if (!revs->limited)
1351                         if (add_parents_to_list(revs, p, &revs->commits) < 0)
1352                                 return rewrite_one_error;
1353                 if (p->parents && p->parents->next)
1354                         return rewrite_one_ok;
1355                 if (p->object.flags & UNINTERESTING)
1356                         return rewrite_one_ok;
1357                 if (!(p->object.flags & TREESAME))
1358                         return rewrite_one_ok;
1359                 if (!p->parents)
1360                         return rewrite_one_noparents;
1361                 *pp = p->parents->item;
1362         }
1363 }
1364
1365 static void remove_duplicate_parents(struct commit *commit)
1366 {
1367         struct commit_list **pp, *p;
1368
1369         /* Examine existing parents while marking ones we have seen... */
1370         pp = &commit->parents;
1371         while ((p = *pp) != NULL) {
1372                 struct commit *parent = p->item;
1373                 if (parent->object.flags & TMP_MARK) {
1374                         *pp = p->next;
1375                         continue;
1376                 }
1377                 parent->object.flags |= TMP_MARK;
1378                 pp = &p->next;
1379         }
1380         /* ... and clear the temporary mark */
1381         for (p = commit->parents; p; p = p->next)
1382                 p->item->object.flags &= ~TMP_MARK;
1383 }
1384
1385 static int rewrite_parents(struct rev_info *revs, struct commit *commit)
1386 {
1387         struct commit_list **pp = &commit->parents;
1388         while (*pp) {
1389                 struct commit_list *parent = *pp;
1390                 switch (rewrite_one(revs, &parent->item)) {
1391                 case rewrite_one_ok:
1392                         break;
1393                 case rewrite_one_noparents:
1394                         *pp = parent->next;
1395                         continue;
1396                 case rewrite_one_error:
1397                         return -1;
1398                 }
1399                 pp = &parent->next;
1400         }
1401         remove_duplicate_parents(commit);
1402         return 0;
1403 }
1404
1405 static int commit_match(struct commit *commit, struct rev_info *opt)
1406 {
1407         if (!opt->grep_filter)
1408                 return 1;
1409         return grep_buffer(opt->grep_filter,
1410                            NULL, /* we say nothing, not even filename */
1411                            commit->buffer, strlen(commit->buffer));
1412 }
1413
1414 enum commit_action simplify_commit(struct rev_info *revs, struct commit *commit)
1415 {
1416         if (commit->object.flags & SHOWN)
1417                 return commit_ignore;
1418         if (revs->unpacked && has_sha1_pack(commit->object.sha1, revs->ignore_packed))
1419                 return commit_ignore;
1420         if (commit->object.flags & UNINTERESTING)
1421                 return commit_ignore;
1422         if (revs->min_age != -1 && (commit->date > revs->min_age))
1423                 return commit_ignore;
1424         if (revs->no_merges && commit->parents && commit->parents->next)
1425                 return commit_ignore;
1426         if (!commit_match(commit, revs))
1427                 return commit_ignore;
1428         if (revs->prune && revs->dense) {
1429                 /* Commit without changes? */
1430                 if (commit->object.flags & TREESAME) {
1431                         /* drop merges unless we want parenthood */
1432                         if (!revs->parents)
1433                                 return commit_ignore;
1434                         /* non-merge - always ignore it */
1435                         if (!commit->parents || !commit->parents->next)
1436                                 return commit_ignore;
1437                 }
1438                 if (revs->parents && rewrite_parents(revs, commit) < 0)
1439                         return commit_error;
1440         }
1441         return commit_show;
1442 }
1443
1444 static struct commit *get_revision_1(struct rev_info *revs)
1445 {
1446         if (!revs->commits)
1447                 return NULL;
1448
1449         do {
1450                 struct commit_list *entry = revs->commits;
1451                 struct commit *commit = entry->item;
1452
1453                 revs->commits = entry->next;
1454                 free(entry);
1455
1456                 if (revs->reflog_info)
1457                         fake_reflog_parent(revs->reflog_info, commit);
1458
1459                 /*
1460                  * If we haven't done the list limiting, we need to look at
1461                  * the parents here. We also need to do the date-based limiting
1462                  * that we'd otherwise have done in limit_list().
1463                  */
1464                 if (!revs->limited) {
1465                         if (revs->max_age != -1 &&
1466                             (commit->date < revs->max_age))
1467                                 continue;
1468                         if (add_parents_to_list(revs, commit, &revs->commits) < 0)
1469                                 return NULL;
1470                 }
1471
1472                 switch (simplify_commit(revs, commit)) {
1473                 case commit_ignore:
1474                         continue;
1475                 case commit_error:
1476                         return NULL;
1477                 default:
1478                         return commit;
1479                 }
1480         } while (revs->commits);
1481         return NULL;
1482 }
1483
1484 static void gc_boundary(struct object_array *array)
1485 {
1486         unsigned nr = array->nr;
1487         unsigned alloc = array->alloc;
1488         struct object_array_entry *objects = array->objects;
1489
1490         if (alloc <= nr) {
1491                 unsigned i, j;
1492                 for (i = j = 0; i < nr; i++) {
1493                         if (objects[i].item->flags & SHOWN)
1494                                 continue;
1495                         if (i != j)
1496                                 objects[j] = objects[i];
1497                         j++;
1498                 }
1499                 for (i = j; i < nr; i++)
1500                         objects[i].item = NULL;
1501                 array->nr = j;
1502         }
1503 }
1504
1505 struct commit *get_revision(struct rev_info *revs)
1506 {
1507         struct commit *c = NULL;
1508         struct commit_list *l;
1509
1510         if (revs->boundary == 2) {
1511                 unsigned i;
1512                 struct object_array *array = &revs->boundary_commits;
1513                 struct object_array_entry *objects = array->objects;
1514                 for (i = 0; i < array->nr; i++) {
1515                         c = (struct commit *)(objects[i].item);
1516                         if (!c)
1517                                 continue;
1518                         if (!(c->object.flags & CHILD_SHOWN))
1519                                 continue;
1520                         if (!(c->object.flags & SHOWN))
1521                                 break;
1522                 }
1523                 if (array->nr <= i)
1524                         return NULL;
1525
1526                 c->object.flags |= SHOWN | BOUNDARY;
1527                 return c;
1528         }
1529
1530         if (revs->reverse) {
1531                 int limit = -1;
1532
1533                 if (0 <= revs->max_count) {
1534                         limit = revs->max_count;
1535                         if (0 < revs->skip_count)
1536                                 limit += revs->skip_count;
1537                 }
1538                 l = NULL;
1539                 while ((c = get_revision_1(revs))) {
1540                         commit_list_insert(c, &l);
1541                         if ((0 < limit) && !--limit)
1542                                 break;
1543                 }
1544                 revs->commits = l;
1545                 revs->reverse = 0;
1546                 revs->max_count = -1;
1547                 c = NULL;
1548         }
1549
1550         /*
1551          * Now pick up what they want to give us
1552          */
1553         c = get_revision_1(revs);
1554         if (c) {
1555                 while (0 < revs->skip_count) {
1556                         revs->skip_count--;
1557                         c = get_revision_1(revs);
1558                         if (!c)
1559                                 break;
1560                 }
1561         }
1562
1563         /*
1564          * Check the max_count.
1565          */
1566         switch (revs->max_count) {
1567         case -1:
1568                 break;
1569         case 0:
1570                 c = NULL;
1571                 break;
1572         default:
1573                 revs->max_count--;
1574         }
1575
1576         if (c)
1577                 c->object.flags |= SHOWN;
1578
1579         if (!revs->boundary) {
1580                 return c;
1581         }
1582
1583         if (!c) {
1584                 /*
1585                  * get_revision_1() runs out the commits, and
1586                  * we are done computing the boundaries.
1587                  * switch to boundary commits output mode.
1588                  */
1589                 revs->boundary = 2;
1590                 return get_revision(revs);
1591         }
1592
1593         /*
1594          * boundary commits are the commits that are parents of the
1595          * ones we got from get_revision_1() but they themselves are
1596          * not returned from get_revision_1().  Before returning
1597          * 'c', we need to mark its parents that they could be boundaries.
1598          */
1599
1600         for (l = c->parents; l; l = l->next) {
1601                 struct object *p;
1602                 p = &(l->item->object);
1603                 if (p->flags & (CHILD_SHOWN | SHOWN))
1604                         continue;
1605                 p->flags |= CHILD_SHOWN;
1606                 gc_boundary(&revs->boundary_commits);
1607                 add_object_array(p, NULL, &revs->boundary_commits);
1608         }
1609
1610         return c;
1611 }