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 #include "decorate.h"
  13
  14 volatile show_early_output_fn_t show_early_output;
  15
  16 static char *path_name(struct name_path *path, const char *name)
  17 {
  18         struct name_path *p;
  19         char *n, *m;
  20         int nlen = strlen(name);
  21         int len = nlen + 1;
  22
  23         for (p = path; p; p = p->up) {
  24                 if (p->elem_len)
  25                         len += p->elem_len + 1;
  26         }
  27         n = xmalloc(len);
  28         m = n + len - (nlen + 1);
  29         strcpy(m, name);
  30         for (p = path; p; p = p->up) {
  31                 if (p->elem_len) {
  32                         m -= p->elem_len + 1;
  33                         memcpy(m, p->elem, p->elem_len);
  34                         m[p->elem_len] = '/';
  35                 }
  36         }
  37         return n;
  38 }
  39
  40 void add_object(struct object *obj,
  41                 struct object_array *p,
  42                 struct name_path *path,
  43                 const char *name)
  44 {
  45         add_object_array(obj, path_name(path, name), p);
  46 }
  47
  48 static void mark_blob_uninteresting(struct blob *blob)
  49 {
  50         if (!blob)
  51                 return;
  52         if (blob->object.flags & UNINTERESTING)
  53                 return;
  54         blob->object.flags |= UNINTERESTING;
  55 }
  56
  57 void mark_tree_uninteresting(struct tree *tree)
  58 {
  59         struct tree_desc desc;
  60         struct name_entry entry;
  61         struct object *obj = &tree->object;
  62
  63         if (!tree)
  64                 return;
  65         if (obj->flags & UNINTERESTING)
  66                 return;
  67         obj->flags |= UNINTERESTING;
  68         if (!has_sha1_file(obj->sha1))
  69                 return;
  70         if (parse_tree(tree) < 0)
  71                 die("bad tree %s", sha1_to_hex(obj->sha1));
  72
  73         init_tree_desc(&desc, tree->buffer, tree->size);
  74         while (tree_entry(&desc, &entry)) {
  75                 switch (object_type(entry.mode)) {
  76                 case OBJ_TREE:
  77                         mark_tree_uninteresting(lookup_tree(entry.sha1));
  78                         break;
  79                 case OBJ_BLOB:
  80                         mark_blob_uninteresting(lookup_blob(entry.sha1));
  81                         break;
  82                 default:
  83                         /* Subproject commit - not in this repository */
  84                         break;
  85                 }
  86         }
  87
  88         /*
  89          * We don't care about the tree any more
  90          * after it has been marked uninteresting.
  91          */
  92         free(tree->buffer);
  93         tree->buffer = NULL;
  94 }
  95
  96 void mark_parents_uninteresting(struct commit *commit)
  97 {
  98         struct commit_list *parents = commit->parents;
  99
 100         while (parents) {
 101                 struct commit *commit = parents->item;
 102                 if (!(commit->object.flags & UNINTERESTING)) {
 103                         commit->object.flags |= UNINTERESTING;
 104
 105                         /*
 106                          * Normally we haven't parsed the parent
 107                          * yet, so we won't have a parent of a parent
 108                          * here. However, it may turn out that we've
 109                          * reached this commit some other way (where it
 110                          * wasn't uninteresting), in which case we need
 111                          * to mark its parents recursively too..
 112                          */
 113                         if (commit->parents)
 114                                 mark_parents_uninteresting(commit);
 115                 }
 116
 117                 /*
 118                  * A missing commit is ok iff its parent is marked
 119                  * uninteresting.
 120                  *
 121                  * We just mark such a thing parsed, so that when
 122                  * it is popped next time around, we won't be trying
 123                  * to parse it and get an error.
 124                  */
 125                 if (!has_sha1_file(commit->object.sha1))
 126                         commit->object.parsed = 1;
 127                 parents = parents->next;
 128         }
 129 }
 130
 131 static void add_pending_object_with_mode(struct rev_info *revs, struct object *obj, const char *name, unsigned mode)
 132 {
 133         if (revs->no_walk && (obj->flags & UNINTERESTING))
 134                 die("object ranges do not make sense when not walking revisions");
 135         if (revs->reflog_info && obj->type == OBJ_COMMIT &&
 136                         add_reflog_for_walk(revs->reflog_info,
 137                                 (struct commit *)obj, name))
 138                 return;
 139         add_object_array_with_mode(obj, name, &revs->pending, mode);
 140 }
 141
 142 void add_pending_object(struct rev_info *revs, struct object *obj, const char *name)
 143 {
 144         add_pending_object_with_mode(revs, obj, name, S_IFINVALID);
 145 }
 146
 147 void add_head_to_pending(struct rev_info *revs)
 148 {
 149         unsigned char sha1[20];
 150         struct object *obj;
 151         if (get_sha1("HEAD", sha1))
 152                 return;
 153         obj = parse_object(sha1);
 154         if (!obj)
 155                 return;
 156         add_pending_object(revs, obj, "HEAD");
 157 }
 158
 159 static struct object *get_reference(struct rev_info *revs, const char *name, const unsigned char *sha1, unsigned int flags)
 160 {
 161         struct object *object;
 162
 163         object = parse_object(sha1);
 164         if (!object)
 165                 die("bad object %s", name);
 166         object->flags |= flags;
 167         return object;
 168 }
 169
 170 static struct commit *handle_commit(struct rev_info *revs, struct object *object, const char *name)
 171 {
 172         unsigned long flags = object->flags;
 173
 174         /*
 175          * Tag object? Look what it points to..
 176          */
 177         while (object->type == OBJ_TAG) {
 178                 struct tag *tag = (struct tag *) object;
 179                 if (revs->tag_objects && !(flags & UNINTERESTING))
 180                         add_pending_object(revs, object, tag->tag);
 181                 if (!tag->tagged)
 182                         die("bad tag");
 183                 object = parse_object(tag->tagged->sha1);
 184                 if (!object)
 185                         die("bad object %s", sha1_to_hex(tag->tagged->sha1));
 186         }
 187
 188         /*
 189          * Commit object? Just return it, we'll do all the complex
 190          * reachability crud.
 191          */
 192         if (object->type == OBJ_COMMIT) {
 193                 struct commit *commit = (struct commit *)object;
 194                 if (parse_commit(commit) < 0)
 195                         die("unable to parse commit %s", name);
 196                 if (flags & UNINTERESTING) {
 197                         commit->object.flags |= UNINTERESTING;
 198                         mark_parents_uninteresting(commit);
 199                         revs->limited = 1;
 200                 }
 201                 return commit;
 202         }
 203
 204         /*
 205          * Tree object? Either mark it uniniteresting, or add it
 206          * to the list of objects to look at later..
 207          */
 208         if (object->type == OBJ_TREE) {
 209                 struct tree *tree = (struct tree *)object;
 210                 if (!revs->tree_objects)
 211                         return NULL;
 212                 if (flags & UNINTERESTING) {
 213                         mark_tree_uninteresting(tree);
 214                         return NULL;
 215                 }
 216                 add_pending_object(revs, object, "");
 217                 return NULL;
 218         }
 219
 220         /*
 221          * Blob object? You know the drill by now..
 222          */
 223         if (object->type == OBJ_BLOB) {
 224                 struct blob *blob = (struct blob *)object;
 225                 if (!revs->blob_objects)
 226                         return NULL;
 227                 if (flags & UNINTERESTING) {
 228                         mark_blob_uninteresting(blob);
 229                         return NULL;
 230                 }
 231                 add_pending_object(revs, object, "");
 232                 return NULL;
 233         }
 234         die("%s is unknown object", name);
 235 }
 236
 237 static int everybody_uninteresting(struct commit_list *orig)
 238 {
 239         struct commit_list *list = orig;
 240         while (list) {
 241                 struct commit *commit = list->item;
 242                 list = list->next;
 243                 if (commit->object.flags & UNINTERESTING)
 244                         continue;
 245                 return 0;
 246         }
 247         return 1;
 248 }
 249
 250 /*
 251  * The goal is to get REV_TREE_NEW as the result only if the
 252  * diff consists of all '+' (and no other changes), and
 253  * REV_TREE_DIFFERENT otherwise (of course if the trees are
 254  * the same we want REV_TREE_SAME).  That means that once we
 255  * get to REV_TREE_DIFFERENT, we do not have to look any further.
 256  */
 257 static int tree_difference = REV_TREE_SAME;
 258
 259 static void file_add_remove(struct diff_options *options,
 260                     int addremove, unsigned mode,
 261                     const unsigned char *sha1,
 262                     const char *base, const char *path)
 263 {
 264         int diff = REV_TREE_DIFFERENT;
 265
 266         /*
 267          * Is it an add of a new file? It means that the old tree
 268          * didn't have it at all, so we will turn "REV_TREE_SAME" ->
 269          * "REV_TREE_NEW", but leave any "REV_TREE_DIFFERENT" alone
 270          * (and if it already was "REV_TREE_NEW", we'll keep it
 271          * "REV_TREE_NEW" of course).
 272          */
 273         if (addremove == '+') {
 274                 diff = tree_difference;
 275                 if (diff != REV_TREE_SAME)
 276                         return;
 277                 diff = REV_TREE_NEW;
 278         }
 279         tree_difference = diff;
 280         if (tree_difference == REV_TREE_DIFFERENT)
 281                 DIFF_OPT_SET(options, HAS_CHANGES);
 282 }
 283
 284 static void file_change(struct diff_options *options,
 285                  unsigned old_mode, unsigned new_mode,
 286                  const unsigned char *old_sha1,
 287                  const unsigned char *new_sha1,
 288                  const char *base, const char *path)
 289 {
 290         tree_difference = REV_TREE_DIFFERENT;
 291         DIFF_OPT_SET(options, HAS_CHANGES);
 292 }
 293
 294 static int rev_compare_tree(struct rev_info *revs, struct tree *t1, struct tree *t2)
 295 {
 296         if (!t1)
 297                 return REV_TREE_NEW;
 298         if (!t2)
 299                 return REV_TREE_DIFFERENT;
 300         tree_difference = REV_TREE_SAME;
 301         DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
 302         if (diff_tree_sha1(t1->object.sha1, t2->object.sha1, "",
 303                            &revs->pruning) < 0)
 304                 return REV_TREE_DIFFERENT;
 305         return tree_difference;
 306 }
 307
 308 static int rev_same_tree_as_empty(struct rev_info *revs, struct tree *t1)
 309 {
 310         int retval;
 311         void *tree;
 312         unsigned long size;
 313         struct tree_desc empty, real;
 314
 315         if (!t1)
 316                 return 0;
 317
 318         tree = read_object_with_reference(t1->object.sha1, tree_type, &size, NULL);
 319         if (!tree)
 320                 return 0;
 321         init_tree_desc(&real, tree, size);
 322         init_tree_desc(&empty, "", 0);
 323
 324         tree_difference = REV_TREE_SAME;
 325         DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
 326         retval = diff_tree(&empty, &real, "", &revs->pruning);
 327         free(tree);
 328
 329         return retval >= 0 && (tree_difference == REV_TREE_SAME);
 330 }
 331
 332 static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
 333 {
 334         struct commit_list **pp, *parent;
 335         int tree_changed = 0, tree_same = 0;
 336
 337         /*
 338          * If we don't do pruning, everything is interesting
 339          */
 340         if (!revs->prune)
 341                 return;
 342
 343         if (!commit->tree)
 344                 return;
 345
 346         if (!commit->parents) {
 347                 if (rev_same_tree_as_empty(revs, commit->tree))
 348                         commit->object.flags |= TREESAME;
 349                 return;
 350         }
 351
 352         /*
 353          * Normal non-merge commit? If we don't want to make the
 354          * history dense, we consider it always to be a change..
 355          */
 356         if (!revs->dense && !commit->parents->next)
 357                 return;
 358
 359         pp = &commit->parents;
 360         while ((parent = *pp) != NULL) {
 361                 struct commit *p = parent->item;
 362
 363                 if (parse_commit(p) < 0)
 364                         die("cannot simplify commit %s (because of %s)",
 365                             sha1_to_hex(commit->object.sha1),
 366                             sha1_to_hex(p->object.sha1));
 367                 switch (rev_compare_tree(revs, p->tree, commit->tree)) {
 368                 case REV_TREE_SAME:
 369                         tree_same = 1;
 370                         if (!revs->simplify_history || (p->object.flags & UNINTERESTING)) {
 371                                 /* Even if a merge with an uninteresting
 372                                  * side branch brought the entire change
 373                                  * we are interested in, we do not want
 374                                  * to lose the other branches of this
 375                                  * merge, so we just keep going.
 376                                  */
 377                                 pp = &parent->next;
 378                                 continue;
 379                         }
 380                         parent->next = NULL;
 381                         commit->parents = parent;
 382                         commit->object.flags |= TREESAME;
 383                         return;
 384
 385                 case REV_TREE_NEW:
 386                         if (revs->remove_empty_trees &&
 387                             rev_same_tree_as_empty(revs, p->tree)) {
 388                                 /* We are adding all the specified
 389                                  * paths from this parent, so the
 390                                  * history beyond this parent is not
 391                                  * interesting.  Remove its parents
 392                                  * (they are grandparents for us).
 393                                  * IOW, we pretend this parent is a
 394                                  * "root" commit.
 395                                  */
 396                                 if (parse_commit(p) < 0)
 397                                         die("cannot simplify commit %s (invalid %s)",
 398                                             sha1_to_hex(commit->object.sha1),
 399                                             sha1_to_hex(p->object.sha1));
 400                                 p->parents = NULL;
 401                         }
 402                 /* fallthrough */
 403                 case REV_TREE_DIFFERENT:
 404                         tree_changed = 1;
 405                         pp = &parent->next;
 406                         continue;
 407                 }
 408                 die("bad tree compare for commit %s", sha1_to_hex(commit->object.sha1));
 409         }
 410         if (tree_changed && !tree_same)
 411                 return;
 412         commit->object.flags |= TREESAME;
 413 }
 414
 415 static int add_parents_to_list(struct rev_info *revs, struct commit *commit, struct commit_list **list)
 416 {
 417         struct commit_list *parent = commit->parents;
 418         unsigned left_flag;
 419         int add, rest;
 420
 421         if (commit->object.flags & ADDED)
 422                 return 0;
 423         commit->object.flags |= ADDED;
 424
 425         /*
 426          * If the commit is uninteresting, don't try to
 427          * prune parents - we want the maximal uninteresting
 428          * set.
 429          *
 430          * Normally we haven't parsed the parent
 431          * yet, so we won't have a parent of a parent
 432          * here. However, it may turn out that we've
 433          * reached this commit some other way (where it
 434          * wasn't uninteresting), in which case we need
 435          * to mark its parents recursively too..
 436          */
 437         if (commit->object.flags & UNINTERESTING) {
 438                 while (parent) {
 439                         struct commit *p = parent->item;
 440                         parent = parent->next;
 441                         if (parse_commit(p) < 0)
 442                                 return -1;
 443                         p->object.flags |= UNINTERESTING;
 444                         if (p->parents)
 445                                 mark_parents_uninteresting(p);
 446                         if (p->object.flags & SEEN)
 447                                 continue;
 448                         p->object.flags |= SEEN;
 449                         insert_by_date(p, list);
 450                 }
 451                 return 0;
 452         }
 453
 454         /*
 455          * Ok, the commit wasn't uninteresting. Try to
 456          * simplify the commit history and find the parent
 457          * that has no differences in the path set if one exists.
 458          */
 459         try_to_simplify_commit(revs, commit);
 460
 461         if (revs->no_walk)
 462                 return 0;
 463
 464         left_flag = (commit->object.flags & SYMMETRIC_LEFT);
 465
 466         rest = !revs->first_parent_only;
 467         for (parent = commit->parents, add = 1; parent; add = rest) {
 468                 struct commit *p = parent->item;
 469
 470                 parent = parent->next;
 471                 if (parse_commit(p) < 0)
 472                         return -1;
 473                 p->object.flags |= left_flag;
 474                 if (p->object.flags & SEEN)
 475                         continue;
 476                 p->object.flags |= SEEN;
 477                 if (add)
 478                         insert_by_date(p, list);
 479         }
 480         return 0;
 481 }
 482
 483 static void cherry_pick_list(struct commit_list *list, struct rev_info *revs)
 484 {
 485         struct commit_list *p;
 486         int left_count = 0, right_count = 0;
 487         int left_first;
 488         struct patch_ids ids;
 489
 490         /* First count the commits on the left and on the right */
 491         for (p = list; p; p = p->next) {
 492                 struct commit *commit = p->item;
 493                 unsigned flags = commit->object.flags;
 494                 if (flags & BOUNDARY)
 495                         ;
 496                 else if (flags & SYMMETRIC_LEFT)
 497                         left_count++;
 498                 else
 499                         right_count++;
 500         }
 501
 502         left_first = left_count < right_count;
 503         init_patch_ids(&ids);
 504         if (revs->diffopt.nr_paths) {
 505                 ids.diffopts.nr_paths = revs->diffopt.nr_paths;
 506                 ids.diffopts.paths = revs->diffopt.paths;
 507                 ids.diffopts.pathlens = revs->diffopt.pathlens;
 508         }
 509
 510         /* Compute patch-ids for one side */
 511         for (p = list; p; p = p->next) {
 512                 struct commit *commit = p->item;
 513                 unsigned flags = commit->object.flags;
 514
 515                 if (flags & BOUNDARY)
 516                         continue;
 517                 /*
 518                  * If we have fewer left, left_first is set and we omit
 519                  * commits on the right branch in this loop.  If we have
 520                  * fewer right, we skip the left ones.
 521                  */
 522                 if (left_first != !!(flags & SYMMETRIC_LEFT))
 523                         continue;
 524                 commit->util = add_commit_patch_id(commit, &ids);
 525         }
 526
 527         /* Check the other side */
 528         for (p = list; p; p = p->next) {
 529                 struct commit *commit = p->item;
 530                 struct patch_id *id;
 531                 unsigned flags = commit->object.flags;
 532
 533                 if (flags & BOUNDARY)
 534                         continue;
 535                 /*
 536                  * If we have fewer left, left_first is set and we omit
 537                  * commits on the left branch in this loop.
 538                  */
 539                 if (left_first == !!(flags & SYMMETRIC_LEFT))
 540                         continue;
 541
 542                 /*
 543                  * Have we seen the same patch id?
 544                  */
 545                 id = has_commit_patch_id(commit, &ids);
 546                 if (!id)
 547                         continue;
 548                 id->seen = 1;
 549                 commit->object.flags |= SHOWN;
 550         }
 551
 552         /* Now check the original side for seen ones */
 553         for (p = list; p; p = p->next) {
 554                 struct commit *commit = p->item;
 555                 struct patch_id *ent;
 556
 557                 ent = commit->util;
 558                 if (!ent)
 559                         continue;
 560                 if (ent->seen)
 561                         commit->object.flags |= SHOWN;
 562                 commit->util = NULL;
 563         }
 564
 565         free_patch_ids(&ids);
 566 }
 567
 568 /* How many extra uninteresting commits we want to see.. */
 569 #define SLOP 5
 570
 571 static int still_interesting(struct commit_list *src, unsigned long date, int slop)
 572 {
 573         /*
 574          * No source list at all? We're definitely done..
 575          */
 576         if (!src)
 577                 return 0;
 578
 579         /*
 580          * Does the destination list contain entries with a date
 581          * before the source list? Definitely _not_ done.
 582          */
 583         if (date < src->item->date)
 584                 return SLOP;
 585
 586         /*
 587          * Does the source list still have interesting commits in
 588          * it? Definitely not done..
 589          */
 590         if (!everybody_uninteresting(src))
 591                 return SLOP;
 592
 593         /* Ok, we're closing in.. */
 594         return slop-1;
 595 }
 596
 597 static int limit_list(struct rev_info *revs)
 598 {
 599         int slop = SLOP;
 600         unsigned long date = ~0ul;
 601         struct commit_list *list = revs->commits;
 602         struct commit_list *newlist = NULL;
 603         struct commit_list **p = &newlist;
 604
 605         while (list) {
 606                 struct commit_list *entry = list;
 607                 struct commit *commit = list->item;
 608                 struct object *obj = &commit->object;
 609                 show_early_output_fn_t show;
 610
 611                 list = list->next;
 612                 free(entry);
 613
 614                 if (revs->max_age != -1 && (commit->date < revs->max_age))
 615                         obj->flags |= UNINTERESTING;
 616                 if (add_parents_to_list(revs, commit, &list) < 0)
 617                         return -1;
 618                 if (obj->flags & UNINTERESTING) {
 619                         mark_parents_uninteresting(commit);
 620                         if (revs->show_all)
 621                                 p = &commit_list_insert(commit, p)->next;
 622                         slop = still_interesting(list, date, slop);
 623                         if (slop)
 624                                 continue;
 625                         /* If showing all, add the whole pending list to the end */
 626                         if (revs->show_all)
 627                                 *p = list;
 628                         break;
 629                 }
 630                 if (revs->min_age != -1 && (commit->date > revs->min_age))
 631                         continue;
 632                 date = commit->date;
 633                 p = &commit_list_insert(commit, p)->next;
 634
 635                 show = show_early_output;
 636                 if (!show)
 637                         continue;
 638
 639                 show(revs, newlist);
 640                 show_early_output = NULL;
 641         }
 642         if (revs->cherry_pick)
 643                 cherry_pick_list(newlist, revs);
 644
 645         revs->commits = newlist;
 646         return 0;
 647 }
 648
 649 struct all_refs_cb {
 650         int all_flags;
 651         int warned_bad_reflog;
 652         struct rev_info *all_revs;
 653         const char *name_for_errormsg;
 654 };
 655
 656 static int handle_one_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
 657 {
 658         struct all_refs_cb *cb = cb_data;
 659         struct object *object = get_reference(cb->all_revs, path, sha1,
 660                                               cb->all_flags);
 661         add_pending_object(cb->all_revs, object, path);
 662         return 0;
 663 }
 664
 665 static void handle_refs(struct rev_info *revs, unsigned flags,
 666                 int (*for_each)(each_ref_fn, void *))
 667 {
 668         struct all_refs_cb cb;
 669         cb.all_revs = revs;
 670         cb.all_flags = flags;
 671         for_each(handle_one_ref, &cb);
 672 }
 673
 674 static void handle_one_reflog_commit(unsigned char *sha1, void *cb_data)
 675 {
 676         struct all_refs_cb *cb = cb_data;
 677         if (!is_null_sha1(sha1)) {
 678                 struct object *o = parse_object(sha1);
 679                 if (o) {
 680                         o->flags |= cb->all_flags;
 681                         add_pending_object(cb->all_revs, o, "");
 682                 }
 683                 else if (!cb->warned_bad_reflog) {
 684                         warning("reflog of '%s' references pruned commits",
 685                                 cb->name_for_errormsg);
 686                         cb->warned_bad_reflog = 1;
 687                 }
 688         }
 689 }
 690
 691 static int handle_one_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
 692                 const char *email, unsigned long timestamp, int tz,
 693                 const char *message, void *cb_data)
 694 {
 695         handle_one_reflog_commit(osha1, cb_data);
 696         handle_one_reflog_commit(nsha1, cb_data);
 697         return 0;
 698 }
 699
 700 static int handle_one_reflog(const char *path, const unsigned char *sha1, int flag, void *cb_data)
 701 {
 702         struct all_refs_cb *cb = cb_data;
 703         cb->warned_bad_reflog = 0;
 704         cb->name_for_errormsg = path;
 705         for_each_reflog_ent(path, handle_one_reflog_ent, cb_data);
 706         return 0;
 707 }
 708
 709 static void handle_reflog(struct rev_info *revs, unsigned flags)
 710 {
 711         struct all_refs_cb cb;
 712         cb.all_revs = revs;
 713         cb.all_flags = flags;
 714         for_each_reflog(handle_one_reflog, &cb);
 715 }
 716
 717 static int add_parents_only(struct rev_info *revs, const char *arg, int flags)
 718 {
 719         unsigned char sha1[20];
 720         struct object *it;
 721         struct commit *commit;
 722         struct commit_list *parents;
 723
 724         if (*arg == '^') {
 725                 flags ^= UNINTERESTING;
 726                 arg++;
 727         }
 728         if (get_sha1(arg, sha1))
 729                 return 0;
 730         while (1) {
 731                 it = get_reference(revs, arg, sha1, 0);
 732                 if (it->type != OBJ_TAG)
 733                         break;
 734                 if (!((struct tag*)it)->tagged)
 735                         return 0;
 736                 hashcpy(sha1, ((struct tag*)it)->tagged->sha1);
 737         }
 738         if (it->type != OBJ_COMMIT)
 739                 return 0;
 740         commit = (struct commit *)it;
 741         for (parents = commit->parents; parents; parents = parents->next) {
 742                 it = &parents->item->object;
 743                 it->flags |= flags;
 744                 add_pending_object(revs, it, arg);
 745         }
 746         return 1;
 747 }
 748
 749 void init_revisions(struct rev_info *revs, const char *prefix)
 750 {
 751         memset(revs, 0, sizeof(*revs));
 752
 753         revs->abbrev = DEFAULT_ABBREV;
 754         revs->ignore_merges = 1;
 755         revs->simplify_history = 1;
 756         DIFF_OPT_SET(&revs->pruning, RECURSIVE);
 757         DIFF_OPT_SET(&revs->pruning, QUIET);
 758         revs->pruning.add_remove = file_add_remove;
 759         revs->pruning.change = file_change;
 760         revs->lifo = 1;
 761         revs->dense = 1;
 762         revs->prefix = prefix;
 763         revs->max_age = -1;
 764         revs->min_age = -1;
 765         revs->skip_count = -1;
 766         revs->max_count = -1;
 767
 768         revs->commit_format = CMIT_FMT_DEFAULT;
 769
 770         diff_setup(&revs->diffopt);
 771         if (prefix && !revs->diffopt.prefix) {
 772                 revs->diffopt.prefix = prefix;
 773                 revs->diffopt.prefix_length = strlen(prefix);
 774         }
 775 }
 776
 777 static void add_pending_commit_list(struct rev_info *revs,
 778                                     struct commit_list *commit_list,
 779                                     unsigned int flags)
 780 {
 781         while (commit_list) {
 782                 struct object *object = &commit_list->item->object;
 783                 object->flags |= flags;
 784                 add_pending_object(revs, object, sha1_to_hex(object->sha1));
 785                 commit_list = commit_list->next;
 786         }
 787 }
 788
 789 static void prepare_show_merge(struct rev_info *revs)
 790 {
 791         struct commit_list *bases;
 792         struct commit *head, *other;
 793         unsigned char sha1[20];
 794         const char **prune = NULL;
 795         int i, prune_num = 1; /* counting terminating NULL */
 796
 797         if (get_sha1("HEAD", sha1) || !(head = lookup_commit(sha1)))
 798                 die("--merge without HEAD?");
 799         if (get_sha1("MERGE_HEAD", sha1) || !(other = lookup_commit(sha1)))
 800                 die("--merge without MERGE_HEAD?");
 801         add_pending_object(revs, &head->object, "HEAD");
 802         add_pending_object(revs, &other->object, "MERGE_HEAD");
 803         bases = get_merge_bases(head, other, 1);
 804         add_pending_commit_list(revs, bases, UNINTERESTING);
 805         free_commit_list(bases);
 806         head->object.flags |= SYMMETRIC_LEFT;
 807
 808         if (!active_nr)
 809                 read_cache();
 810         for (i = 0; i < active_nr; i++) {
 811                 struct cache_entry *ce = active_cache[i];
 812                 if (!ce_stage(ce))
 813                         continue;
 814                 if (ce_path_match(ce, revs->prune_data)) {
 815                         prune_num++;
 816                         prune = xrealloc(prune, sizeof(*prune) * prune_num);
 817                         prune[prune_num-2] = ce->name;
 818                         prune[prune_num-1] = NULL;
 819                 }
 820                 while ((i+1 < active_nr) &&
 821                        ce_same_name(ce, active_cache[i+1]))
 822                         i++;
 823         }
 824         revs->prune_data = prune;
 825         revs->limited = 1;
 826 }
 827
 828 int handle_revision_arg(const char *arg, struct rev_info *revs,
 829                         int flags,
 830                         int cant_be_filename)
 831 {
 832         unsigned mode;
 833         char *dotdot;
 834         struct object *object;
 835         unsigned char sha1[20];
 836         int local_flags;
 837
 838         dotdot = strstr(arg, "..");
 839         if (dotdot) {
 840                 unsigned char from_sha1[20];
 841                 const char *next = dotdot + 2;
 842                 const char *this = arg;
 843                 int symmetric = *next == '.';
 844                 unsigned int flags_exclude = flags ^ UNINTERESTING;
 845
 846                 *dotdot = 0;
 847                 next += symmetric;
 848
 849                 if (!*next)
 850                         next = "HEAD";
 851                 if (dotdot == arg)
 852                         this = "HEAD";
 853                 if (!get_sha1(this, from_sha1) &&
 854                     !get_sha1(next, sha1)) {
 855                         struct commit *a, *b;
 856                         struct commit_list *exclude;
 857
 858                         a = lookup_commit_reference(from_sha1);
 859                         b = lookup_commit_reference(sha1);
 860                         if (!a || !b) {
 861                                 die(symmetric ?
 862                                     "Invalid symmetric difference expression %s...%s" :
 863                                     "Invalid revision range %s..%s",
 864                                     arg, next);
 865                         }
 866
 867                         if (!cant_be_filename) {
 868                                 *dotdot = '.';
 869                                 verify_non_filename(revs->prefix, arg);
 870                         }
 871
 872                         if (symmetric) {
 873                                 exclude = get_merge_bases(a, b, 1);
 874                                 add_pending_commit_list(revs, exclude,
 875                                                         flags_exclude);
 876                                 free_commit_list(exclude);
 877                                 a->object.flags |= flags | SYMMETRIC_LEFT;
 878                         } else
 879                                 a->object.flags |= flags_exclude;
 880                         b->object.flags |= flags;
 881                         add_pending_object(revs, &a->object, this);
 882                         add_pending_object(revs, &b->object, next);
 883                         return 0;
 884                 }
 885                 *dotdot = '.';
 886         }
 887         dotdot = strstr(arg, "^@");
 888         if (dotdot && !dotdot[2]) {
 889                 *dotdot = 0;
 890                 if (add_parents_only(revs, arg, flags))
 891                         return 0;
 892                 *dotdot = '^';
 893         }
 894         dotdot = strstr(arg, "^!");
 895         if (dotdot && !dotdot[2]) {
 896                 *dotdot = 0;
 897                 if (!add_parents_only(revs, arg, flags ^ UNINTERESTING))
 898                         *dotdot = '^';
 899         }
 900
 901         local_flags = 0;
 902         if (*arg == '^') {
 903                 local_flags = UNINTERESTING;
 904                 arg++;
 905         }
 906         if (get_sha1_with_mode(arg, sha1, &mode))
 907                 return -1;
 908         if (!cant_be_filename)
 909                 verify_non_filename(revs->prefix, arg);
 910         object = get_reference(revs, arg, sha1, flags ^ local_flags);
 911         add_pending_object_with_mode(revs, object, arg, mode);
 912         return 0;
 913 }
 914
 915 static void add_grep(struct rev_info *revs, const char *ptn, enum grep_pat_token what)
 916 {
 917         if (!revs->grep_filter) {
 918                 struct grep_opt *opt = xcalloc(1, sizeof(*opt));
 919                 opt->status_only = 1;
 920                 opt->pattern_tail = &(opt->pattern_list);
 921                 opt->regflags = REG_NEWLINE;
 922                 revs->grep_filter = opt;
 923         }
 924         append_grep_pattern(revs->grep_filter, ptn,
 925                             "command line", 0, what);
 926 }
 927
 928 static void add_header_grep(struct rev_info *revs, const char *field, const char *pattern)
 929 {
 930         char *pat;
 931         const char *prefix;
 932         int patlen, fldlen;
 933
 934         fldlen = strlen(field);
 935         patlen = strlen(pattern);
 936         pat = xmalloc(patlen + fldlen + 10);
 937         prefix = ".*";
 938         if (*pattern == '^') {
 939                 prefix = "";
 940                 pattern++;
 941         }
 942         sprintf(pat, "^%s %s%s", field, prefix, pattern);
 943         add_grep(revs, pat, GREP_PATTERN_HEAD);
 944 }
 945
 946 static void add_message_grep(struct rev_info *revs, const char *pattern)
 947 {
 948         add_grep(revs, pattern, GREP_PATTERN_BODY);
 949 }
 950
 951 static void add_ignore_packed(struct rev_info *revs, const char *name)
 952 {
 953         int num = ++revs->num_ignore_packed;
 954
 955         revs->ignore_packed = xrealloc(revs->ignore_packed,
 956                                        sizeof(const char **) * (num + 1));
 957         revs->ignore_packed[num-1] = name;
 958         revs->ignore_packed[num] = NULL;
 959 }
 960
 961 /*
 962  * Parse revision information, filling in the "rev_info" structure,
 963  * and removing the used arguments from the argument list.
 964  *
 965  * Returns the number of arguments left that weren't recognized
 966  * (which are also moved to the head of the argument list)
 967  */
 968 int setup_revisions(int argc, const char **argv, struct rev_info *revs, const char *def)
 969 {
 970         int i, flags, seen_dashdash, show_merge;
 971         const char **unrecognized = argv + 1;
 972         int left = 1;
 973         int all_match = 0;
 974         int regflags = 0;
 975         int fixed = 0;
 976
 977         /* First, search for "--" */
 978         seen_dashdash = 0;
 979         for (i = 1; i < argc; i++) {
 980                 const char *arg = argv[i];
 981                 if (strcmp(arg, "--"))
 982                         continue;
 983                 argv[i] = NULL;
 984                 argc = i;
 985                 if (argv[i + 1])
 986                         revs->prune_data = get_pathspec(revs->prefix, argv + i + 1);
 987                 seen_dashdash = 1;
 988                 break;
 989         }
 990
 991         flags = show_merge = 0;
 992         for (i = 1; i < argc; i++) {
 993                 const char *arg = argv[i];
 994                 if (*arg == '-') {
 995                         int opts;
 996                         if (!prefixcmp(arg, "--max-count=")) {
 997                                 revs->max_count = atoi(arg + 12);
 998                                 continue;
 999                         }
1000                         if (!prefixcmp(arg, "--skip=")) {
1001                                 revs->skip_count = atoi(arg + 7);
1002                                 continue;
1003                         }
1004                         /* accept -<digit>, like traditional "head" */
1005                         if ((*arg == '-') && isdigit(arg[1])) {
1006                                 revs->max_count = atoi(arg + 1);
1007                                 continue;
1008                         }
1009                         if (!strcmp(arg, "-n")) {
1010                                 if (argc <= i + 1)
1011                                         die("-n requires an argument");
1012                                 revs->max_count = atoi(argv[++i]);
1013                                 continue;
1014                         }
1015                         if (!prefixcmp(arg, "-n")) {
1016                                 revs->max_count = atoi(arg + 2);
1017                                 continue;
1018                         }
1019                         if (!prefixcmp(arg, "--max-age=")) {
1020                                 revs->max_age = atoi(arg + 10);
1021                                 continue;
1022                         }
1023                         if (!prefixcmp(arg, "--since=")) {
1024                                 revs->max_age = approxidate(arg + 8);
1025                                 continue;
1026                         }
1027                         if (!prefixcmp(arg, "--after=")) {
1028                                 revs->max_age = approxidate(arg + 8);
1029                                 continue;
1030                         }
1031                         if (!prefixcmp(arg, "--min-age=")) {
1032                                 revs->min_age = atoi(arg + 10);
1033                                 continue;
1034                         }
1035                         if (!prefixcmp(arg, "--before=")) {
1036                                 revs->min_age = approxidate(arg + 9);
1037                                 continue;
1038                         }
1039                         if (!prefixcmp(arg, "--until=")) {
1040                                 revs->min_age = approxidate(arg + 8);
1041                                 continue;
1042                         }
1043                         if (!strcmp(arg, "--all")) {
1044                                 handle_refs(revs, flags, for_each_ref);
1045                                 continue;
1046                         }
1047                         if (!strcmp(arg, "--branches")) {
1048                                 handle_refs(revs, flags, for_each_branch_ref);
1049                                 continue;
1050                         }
1051                         if (!strcmp(arg, "--tags")) {
1052                                 handle_refs(revs, flags, for_each_tag_ref);
1053                                 continue;
1054                         }
1055                         if (!strcmp(arg, "--remotes")) {
1056                                 handle_refs(revs, flags, for_each_remote_ref);
1057                                 continue;
1058                         }
1059                         if (!strcmp(arg, "--first-parent")) {
1060                                 revs->first_parent_only = 1;
1061                                 continue;
1062                         }
1063                         if (!strcmp(arg, "--reflog")) {
1064                                 handle_reflog(revs, flags);
1065                                 continue;
1066                         }
1067                         if (!strcmp(arg, "-g") ||
1068                                         !strcmp(arg, "--walk-reflogs")) {
1069                                 init_reflog_walk(&revs->reflog_info);
1070                                 continue;
1071                         }
1072                         if (!strcmp(arg, "--not")) {
1073                                 flags ^= UNINTERESTING;
1074                                 continue;
1075                         }
1076                         if (!strcmp(arg, "--default")) {
1077                                 if (++i >= argc)
1078                                         die("bad --default argument");
1079                                 def = argv[i];
1080                                 continue;
1081                         }
1082                         if (!strcmp(arg, "--merge")) {
1083                                 show_merge = 1;
1084                                 continue;
1085                         }
1086                         if (!strcmp(arg, "--topo-order")) {
1087                                 revs->lifo = 1;
1088                                 revs->topo_order = 1;
1089                                 continue;
1090                         }
1091                         if (!strcmp(arg, "--date-order")) {
1092                                 revs->lifo = 0;
1093                                 revs->topo_order = 1;
1094                                 continue;
1095                         }
1096                         if (!prefixcmp(arg, "--early-output")) {
1097                                 int count = 100;
1098                                 switch (arg[14]) {
1099                                 case '=':
1100                                         count = atoi(arg+15);
1101                                         /* Fallthrough */
1102                                 case 0:
1103                                         revs->topo_order = 1;
1104                                         revs->early_output = count;
1105                                         continue;
1106                                 }
1107                         }
1108                         if (!strcmp(arg, "--parents")) {
1109                                 revs->parents = 1;
1110                                 continue;
1111                         }
1112                         if (!strcmp(arg, "--dense")) {
1113                                 revs->dense = 1;
1114                                 continue;
1115                         }
1116                         if (!strcmp(arg, "--sparse")) {
1117                                 revs->dense = 0;
1118                                 continue;
1119                         }
1120                         if (!strcmp(arg, "--show-all")) {
1121                                 revs->show_all = 1;
1122                                 continue;
1123                         }
1124                         if (!strcmp(arg, "--remove-empty")) {
1125                                 revs->remove_empty_trees = 1;
1126                                 continue;
1127                         }
1128                         if (!strcmp(arg, "--no-merges")) {
1129                                 revs->no_merges = 1;
1130                                 continue;
1131                         }
1132                         if (!strcmp(arg, "--boundary")) {
1133                                 revs->boundary = 1;
1134                                 continue;
1135                         }
1136                         if (!strcmp(arg, "--left-right")) {
1137                                 revs->left_right = 1;
1138                                 continue;
1139                         }
1140                         if (!strcmp(arg, "--cherry-pick")) {
1141                                 revs->cherry_pick = 1;
1142                                 revs->limited = 1;
1143                                 continue;
1144                         }
1145                         if (!strcmp(arg, "--objects")) {
1146                                 revs->tag_objects = 1;
1147                                 revs->tree_objects = 1;
1148                                 revs->blob_objects = 1;
1149                                 continue;
1150                         }
1151                         if (!strcmp(arg, "--objects-edge")) {
1152                                 revs->tag_objects = 1;
1153                                 revs->tree_objects = 1;
1154                                 revs->blob_objects = 1;
1155                                 revs->edge_hint = 1;
1156                                 continue;
1157                         }
1158                         if (!strcmp(arg, "--unpacked")) {
1159                                 revs->unpacked = 1;
1160                                 free(revs->ignore_packed);
1161                                 revs->ignore_packed = NULL;
1162                                 revs->num_ignore_packed = 0;
1163                                 continue;
1164                         }
1165                         if (!prefixcmp(arg, "--unpacked=")) {
1166                                 revs->unpacked = 1;
1167                                 add_ignore_packed(revs, arg+11);
1168                                 continue;
1169                         }
1170                         if (!strcmp(arg, "-r")) {
1171                                 revs->diff = 1;
1172                                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1173                                 continue;
1174                         }
1175                         if (!strcmp(arg, "-t")) {
1176                                 revs->diff = 1;
1177                                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1178                                 DIFF_OPT_SET(&revs->diffopt, TREE_IN_RECURSIVE);
1179                                 continue;
1180                         }
1181                         if (!strcmp(arg, "-m")) {
1182                                 revs->ignore_merges = 0;
1183                                 continue;
1184                         }
1185                         if (!strcmp(arg, "-c")) {
1186                                 revs->diff = 1;
1187                                 revs->dense_combined_merges = 0;
1188                                 revs->combine_merges = 1;
1189                                 continue;
1190                         }
1191                         if (!strcmp(arg, "--cc")) {
1192                                 revs->diff = 1;
1193                                 revs->dense_combined_merges = 1;
1194                                 revs->combine_merges = 1;
1195                                 continue;
1196                         }
1197                         if (!strcmp(arg, "-v")) {
1198                                 revs->verbose_header = 1;
1199                                 continue;
1200                         }
1201                         if (!prefixcmp(arg, "--pretty")) {
1202                                 revs->verbose_header = 1;
1203                                 revs->commit_format = get_commit_format(arg+8);
1204                                 continue;
1205                         }
1206                         if (!strcmp(arg, "--root")) {
1207                                 revs->show_root_diff = 1;
1208                                 continue;
1209                         }
1210                         if (!strcmp(arg, "--no-commit-id")) {
1211                                 revs->no_commit_id = 1;
1212                                 continue;
1213                         }
1214                         if (!strcmp(arg, "--always")) {
1215                                 revs->always_show_header = 1;
1216                                 continue;
1217                         }
1218                         if (!strcmp(arg, "--no-abbrev")) {
1219                                 revs->abbrev = 0;
1220                                 continue;
1221                         }
1222                         if (!strcmp(arg, "--abbrev")) {
1223                                 revs->abbrev = DEFAULT_ABBREV;
1224                                 continue;
1225                         }
1226                         if (!prefixcmp(arg, "--abbrev=")) {
1227                                 revs->abbrev = strtoul(arg + 9, NULL, 10);
1228                                 if (revs->abbrev < MINIMUM_ABBREV)
1229                                         revs->abbrev = MINIMUM_ABBREV;
1230                                 else if (revs->abbrev > 40)
1231                                         revs->abbrev = 40;
1232                                 continue;
1233                         }
1234                         if (!strcmp(arg, "--abbrev-commit")) {
1235                                 revs->abbrev_commit = 1;
1236                                 continue;
1237                         }
1238                         if (!strcmp(arg, "--full-diff")) {
1239                                 revs->diff = 1;
1240                                 revs->full_diff = 1;
1241                                 continue;
1242                         }
1243                         if (!strcmp(arg, "--full-history")) {
1244                                 revs->simplify_history = 0;
1245                                 continue;
1246                         }
1247                         if (!strcmp(arg, "--relative-date")) {
1248                                 revs->date_mode = DATE_RELATIVE;
1249                                 continue;
1250                         }
1251                         if (!strncmp(arg, "--date=", 7)) {
1252                                 revs->date_mode = parse_date_format(arg + 7);
1253                                 continue;
1254                         }
1255                         if (!strcmp(arg, "--log-size")) {
1256                                 revs->show_log_size = 1;
1257                                 continue;
1258                         }
1259
1260                         /*
1261                          * Grepping the commit log
1262                          */
1263                         if (!prefixcmp(arg, "--author=")) {
1264                                 add_header_grep(revs, "author", arg+9);
1265                                 continue;
1266                         }
1267                         if (!prefixcmp(arg, "--committer=")) {
1268                                 add_header_grep(revs, "committer", arg+12);
1269                                 continue;
1270                         }
1271                         if (!prefixcmp(arg, "--grep=")) {
1272                                 add_message_grep(revs, arg+7);
1273                                 continue;
1274                         }
1275                         if (!strcmp(arg, "--extended-regexp") ||
1276                             !strcmp(arg, "-E")) {
1277                                 regflags |= REG_EXTENDED;
1278                                 continue;
1279                         }
1280                         if (!strcmp(arg, "--regexp-ignore-case") ||
1281                             !strcmp(arg, "-i")) {
1282                                 regflags |= REG_ICASE;
1283                                 continue;
1284                         }
1285                         if (!strcmp(arg, "--fixed-strings") ||
1286                             !strcmp(arg, "-F")) {
1287                                 fixed = 1;
1288                                 continue;
1289                         }
1290                         if (!strcmp(arg, "--all-match")) {
1291                                 all_match = 1;
1292                                 continue;
1293                         }
1294                         if (!prefixcmp(arg, "--encoding=")) {
1295                                 arg += 11;
1296                                 if (strcmp(arg, "none"))
1297                                         git_log_output_encoding = xstrdup(arg);
1298                                 else
1299                                         git_log_output_encoding = "";
1300                                 continue;
1301                         }
1302                         if (!strcmp(arg, "--reverse")) {
1303                                 revs->reverse ^= 1;
1304                                 continue;
1305                         }
1306                         if (!strcmp(arg, "--no-walk")) {
1307                                 revs->no_walk = 1;
1308                                 continue;
1309                         }
1310                         if (!strcmp(arg, "--do-walk")) {
1311                                 revs->no_walk = 0;
1312                                 continue;
1313                         }
1314                         if (!strcmp(arg, "--children")) {
1315                                 revs->children.name = "children";
1316                                 revs->limited = 1;
1317                                 continue;
1318                         }
1319
1320                         opts = diff_opt_parse(&revs->diffopt, argv+i, argc-i);
1321                         if (opts > 0) {
1322                                 i += opts - 1;
1323                                 continue;
1324                         }
1325                         *unrecognized++ = arg;
1326                         left++;
1327                         continue;
1328                 }
1329
1330                 if (handle_revision_arg(arg, revs, flags, seen_dashdash)) {
1331                         int j;
1332                         if (seen_dashdash || *arg == '^')
1333                                 die("bad revision '%s'", arg);
1334
1335                         /* If we didn't have a "--":
1336                          * (1) all filenames must exist;
1337                          * (2) all rev-args must not be interpretable
1338                          *     as a valid filename.
1339                          * but the latter we have checked in the main loop.
1340                          */
1341                         for (j = i; j < argc; j++)
1342                                 verify_filename(revs->prefix, argv[j]);
1343
1344                         revs->prune_data = get_pathspec(revs->prefix,
1345                                                         argv + i);
1346                         break;
1347                 }
1348         }
1349
1350         if (revs->grep_filter) {
1351                 revs->grep_filter->regflags |= regflags;
1352                 revs->grep_filter->fixed = fixed;
1353         }
1354
1355         if (show_merge)
1356                 prepare_show_merge(revs);
1357         if (def && !revs->pending.nr) {
1358                 unsigned char sha1[20];
1359                 struct object *object;
1360                 unsigned mode;
1361                 if (get_sha1_with_mode(def, sha1, &mode))
1362                         die("bad default revision '%s'", def);
1363                 object = get_reference(revs, def, sha1, 0);
1364                 add_pending_object_with_mode(revs, object, def, mode);
1365         }
1366
1367         /* Did the user ask for any diff output? Run the diff! */
1368         if (revs->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT)
1369                 revs->diff = 1;
1370
1371         /* Pickaxe, diff-filter and rename following need diffs */
1372         if (revs->diffopt.pickaxe ||
1373             revs->diffopt.filter ||
1374             DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1375                 revs->diff = 1;
1376
1377         if (revs->topo_order)
1378                 revs->limited = 1;
1379
1380         if (revs->prune_data) {
1381                 diff_tree_setup_paths(revs->prune_data, &revs->pruning);
1382                 /* Can't prune commits with rename following: the paths change.. */
1383                 if (!DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1384                         revs->prune = 1;
1385                 if (!revs->full_diff)
1386                         diff_tree_setup_paths(revs->prune_data, &revs->diffopt);
1387         }
1388         if (revs->combine_merges) {
1389                 revs->ignore_merges = 0;
1390                 if (revs->dense_combined_merges && !revs->diffopt.output_format)
1391                         revs->diffopt.output_format = DIFF_FORMAT_PATCH;
1392         }
1393         revs->diffopt.abbrev = revs->abbrev;
1394         if (diff_setup_done(&revs->diffopt) < 0)
1395                 die("diff_setup_done failed");
1396
1397         if (revs->grep_filter) {
1398                 revs->grep_filter->all_match = all_match;
1399                 compile_grep_patterns(revs->grep_filter);
1400         }
1401
1402         if (revs->reverse && revs->reflog_info)
1403                 die("cannot combine --reverse with --walk-reflogs");
1404         if (revs->parents && revs->children.name)
1405                 die("cannot combine --parents and --children");
1406         return left;
1407 }
1408
1409 static void add_child(struct rev_info *revs, struct commit *parent, struct commit *child)
1410 {
1411         struct commit_list *l = xcalloc(1, sizeof(*l));
1412
1413         l->item = child;
1414         l->next = add_decoration(&revs->children, &parent->object, l);
1415 }
1416
1417 static void set_children(struct rev_info *revs)
1418 {
1419         struct commit_list *l;
1420         for (l = revs->commits; l; l = l->next) {
1421                 struct commit *commit = l->item;
1422                 struct commit_list *p;
1423
1424                 for (p = commit->parents; p; p = p->next)
1425                         add_child(revs, p->item, commit);
1426         }
1427 }
1428
1429 int prepare_revision_walk(struct rev_info *revs)
1430 {
1431         int nr = revs->pending.nr;
1432         struct object_array_entry *e, *list;
1433
1434         e = list = revs->pending.objects;
1435         revs->pending.nr = 0;
1436         revs->pending.alloc = 0;
1437         revs->pending.objects = NULL;
1438         while (--nr >= 0) {
1439                 struct commit *commit = handle_commit(revs, e->item, e->name);
1440                 if (commit) {
1441                         if (!(commit->object.flags & SEEN)) {
1442                                 commit->object.flags |= SEEN;
1443                                 insert_by_date(commit, &revs->commits);
1444                         }
1445                 }
1446                 e++;
1447         }
1448         free(list);
1449
1450         if (revs->no_walk)
1451                 return 0;
1452         if (revs->limited)
1453                 if (limit_list(revs) < 0)
1454                         return -1;
1455         if (revs->topo_order)
1456                 sort_in_topological_order(&revs->commits, revs->lifo);
1457         if (revs->children.name)
1458                 set_children(revs);
1459         return 0;
1460 }
1461
1462 enum rewrite_result {
1463         rewrite_one_ok,
1464         rewrite_one_noparents,
1465         rewrite_one_error,
1466 };
1467
1468 static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp)
1469 {
1470         for (;;) {
1471                 struct commit *p = *pp;
1472                 if (!revs->limited)
1473                         if (add_parents_to_list(revs, p, &revs->commits) < 0)
1474                                 return rewrite_one_error;
1475                 if (p->parents && p->parents->next)
1476                         return rewrite_one_ok;
1477                 if (p->object.flags & UNINTERESTING)
1478                         return rewrite_one_ok;
1479                 if (!(p->object.flags & TREESAME))
1480                         return rewrite_one_ok;
1481                 if (!p->parents)
1482                         return rewrite_one_noparents;
1483                 *pp = p->parents->item;
1484         }
1485 }
1486
1487 static void remove_duplicate_parents(struct commit *commit)
1488 {
1489         struct commit_list **pp, *p;
1490
1491         /* Examine existing parents while marking ones we have seen... */
1492         pp = &commit->parents;
1493         while ((p = *pp) != NULL) {
1494                 struct commit *parent = p->item;
1495                 if (parent->object.flags & TMP_MARK) {
1496                         *pp = p->next;
1497                         continue;
1498                 }
1499                 parent->object.flags |= TMP_MARK;
1500                 pp = &p->next;
1501         }
1502         /* ... and clear the temporary mark */
1503         for (p = commit->parents; p; p = p->next)
1504                 p->item->object.flags &= ~TMP_MARK;
1505 }
1506
1507 static int rewrite_parents(struct rev_info *revs, struct commit *commit)
1508 {
1509         struct commit_list **pp = &commit->parents;
1510         while (*pp) {
1511                 struct commit_list *parent = *pp;
1512                 switch (rewrite_one(revs, &parent->item)) {
1513                 case rewrite_one_ok:
1514                         break;
1515                 case rewrite_one_noparents:
1516                         *pp = parent->next;
1517                         continue;
1518                 case rewrite_one_error:
1519                         return -1;
1520                 }
1521                 pp = &parent->next;
1522         }
1523         remove_duplicate_parents(commit);
1524         return 0;
1525 }
1526
1527 static int commit_match(struct commit *commit, struct rev_info *opt)
1528 {
1529         if (!opt->grep_filter)
1530                 return 1;
1531         return grep_buffer(opt->grep_filter,
1532                            NULL, /* we say nothing, not even filename */
1533                            commit->buffer, strlen(commit->buffer));
1534 }
1535
1536 static inline int want_ancestry(struct rev_info *revs)
1537 {
1538         return (revs->parents || revs->children.name);
1539 }
1540
1541 enum commit_action simplify_commit(struct rev_info *revs, struct commit *commit)
1542 {
1543         if (commit->object.flags & SHOWN)
1544                 return commit_ignore;
1545         if (revs->unpacked && has_sha1_pack(commit->object.sha1, revs->ignore_packed))
1546                 return commit_ignore;
1547         if (revs->show_all)
1548                 return commit_show;
1549         if (commit->object.flags & UNINTERESTING)
1550                 return commit_ignore;
1551         if (revs->min_age != -1 && (commit->date > revs->min_age))
1552                 return commit_ignore;
1553         if (revs->no_merges && commit->parents && commit->parents->next)
1554                 return commit_ignore;
1555         if (!commit_match(commit, revs))
1556                 return commit_ignore;
1557         if (revs->prune && revs->dense) {
1558                 /* Commit without changes? */
1559                 if (commit->object.flags & TREESAME) {
1560                         /* drop merges unless we want parenthood */
1561                         if (!want_ancestry(revs))
1562                                 return commit_ignore;
1563                         /* non-merge - always ignore it */
1564                         if (!commit->parents || !commit->parents->next)
1565                                 return commit_ignore;
1566                 }
1567                 if (want_ancestry(revs) && rewrite_parents(revs, commit) < 0)
1568                         return commit_error;
1569         }
1570         return commit_show;
1571 }
1572
1573 static struct commit *get_revision_1(struct rev_info *revs)
1574 {
1575         if (!revs->commits)
1576                 return NULL;
1577
1578         do {
1579                 struct commit_list *entry = revs->commits;
1580                 struct commit *commit = entry->item;
1581
1582                 revs->commits = entry->next;
1583                 free(entry);
1584
1585                 if (revs->reflog_info)
1586                         fake_reflog_parent(revs->reflog_info, commit);
1587
1588                 /*
1589                  * If we haven't done the list limiting, we need to look at
1590                  * the parents here. We also need to do the date-based limiting
1591                  * that we'd otherwise have done in limit_list().
1592                  */
1593                 if (!revs->limited) {
1594                         if (revs->max_age != -1 &&
1595                             (commit->date < revs->max_age))
1596                                 continue;
1597                         if (add_parents_to_list(revs, commit, &revs->commits) < 0)
1598                                 return NULL;
1599                 }
1600
1601                 switch (simplify_commit(revs, commit)) {
1602                 case commit_ignore:
1603                         continue;
1604                 case commit_error:
1605                         return NULL;
1606                 default:
1607                         return commit;
1608                 }
1609         } while (revs->commits);
1610         return NULL;
1611 }
1612
1613 static void gc_boundary(struct object_array *array)
1614 {
1615         unsigned nr = array->nr;
1616         unsigned alloc = array->alloc;
1617         struct object_array_entry *objects = array->objects;
1618
1619         if (alloc <= nr) {
1620                 unsigned i, j;
1621                 for (i = j = 0; i < nr; i++) {
1622                         if (objects[i].item->flags & SHOWN)
1623                                 continue;
1624                         if (i != j)
1625                                 objects[j] = objects[i];
1626                         j++;
1627                 }
1628                 for (i = j; i < nr; i++)
1629                         objects[i].item = NULL;
1630                 array->nr = j;
1631         }
1632 }
1633
1634 struct commit *get_revision(struct rev_info *revs)
1635 {
1636         struct commit *c = NULL;
1637         struct commit_list *l;
1638
1639         if (revs->boundary == 2) {
1640                 unsigned i;
1641                 struct object_array *array = &revs->boundary_commits;
1642                 struct object_array_entry *objects = array->objects;
1643                 for (i = 0; i < array->nr; i++) {
1644                         c = (struct commit *)(objects[i].item);
1645                         if (!c)
1646                                 continue;
1647                         if (!(c->object.flags & CHILD_SHOWN))
1648                                 continue;
1649                         if (!(c->object.flags & SHOWN))
1650                                 break;
1651                 }
1652                 if (array->nr <= i)
1653                         return NULL;
1654
1655                 c->object.flags |= SHOWN | BOUNDARY;
1656                 return c;
1657         }
1658
1659         if (revs->reverse) {
1660                 int limit = -1;
1661
1662                 if (0 <= revs->max_count) {
1663                         limit = revs->max_count;
1664                         if (0 < revs->skip_count)
1665                                 limit += revs->skip_count;
1666                 }
1667                 l = NULL;
1668                 while ((c = get_revision_1(revs))) {
1669                         commit_list_insert(c, &l);
1670                         if ((0 < limit) && !--limit)
1671                                 break;
1672                 }
1673                 revs->commits = l;
1674                 revs->reverse = 0;
1675                 revs->max_count = -1;
1676                 c = NULL;
1677         }
1678
1679         /*
1680          * Now pick up what they want to give us
1681          */
1682         c = get_revision_1(revs);
1683         if (c) {
1684                 while (0 < revs->skip_count) {
1685                         revs->skip_count--;
1686                         c = get_revision_1(revs);
1687                         if (!c)
1688                                 break;
1689                 }
1690         }
1691
1692         /*
1693          * Check the max_count.
1694          */
1695         switch (revs->max_count) {
1696         case -1:
1697                 break;
1698         case 0:
1699                 c = NULL;
1700                 break;
1701         default:
1702                 revs->max_count--;
1703         }
1704
1705         if (c)
1706                 c->object.flags |= SHOWN;
1707
1708         if (!revs->boundary) {
1709                 return c;
1710         }
1711
1712         if (!c) {
1713                 /*
1714                  * get_revision_1() runs out the commits, and
1715                  * we are done computing the boundaries.
1716                  * switch to boundary commits output mode.
1717                  */
1718                 revs->boundary = 2;
1719                 return get_revision(revs);
1720         }
1721
1722         /*
1723          * boundary commits are the commits that are parents of the
1724          * ones we got from get_revision_1() but they themselves are
1725          * not returned from get_revision_1().  Before returning
1726          * 'c', we need to mark its parents that they could be boundaries.
1727          */
1728
1729         for (l = c->parents; l; l = l->next) {
1730                 struct object *p;
1731                 p = &(l->item->object);
1732                 if (p->flags & (CHILD_SHOWN | SHOWN))
1733                         continue;
1734                 p->flags |= CHILD_SHOWN;
1735                 gc_boundary(&revs->boundary_commits);
1736                 add_object_array(p, NULL, &revs->boundary_commits);
1737         }
1738
1739         return c;
1740 }