git.oblomov.eu Git - git/blob - 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 "graph.h"
  10 #include "grep.h"
  11 #include "reflog-walk.h"
  12 #include "patch-ids.h"
  13 #include "decorate.h"
  14 #include "log-tree.h"
  15
  16 volatile show_early_output_fn_t show_early_output;
  17
  18 static char *path_name(struct name_path *path, const char *name)
  19 {
  20         struct name_path *p;
  21         char *n, *m;
  22         int nlen = strlen(name);
  23         int len = nlen + 1;
  24
  25         for (p = path; p; p = p->up) {
  26                 if (p->elem_len)
  27                         len += p->elem_len + 1;
  28         }
  29         n = xmalloc(len);
  30         m = n + len - (nlen + 1);
  31         strcpy(m, name);
  32         for (p = path; p; p = p->up) {
  33                 if (p->elem_len) {
  34                         m -= p->elem_len + 1;
  35                         memcpy(m, p->elem, p->elem_len);
  36                         m[p->elem_len] = '/';
  37                 }
  38         }
  39         return n;
  40 }
  41
  42 void add_object(struct object *obj,
  43                 struct object_array *p,
  44                 struct name_path *path,
  45                 const char *name)
  46 {
  47         add_object_array(obj, path_name(path, name), p);
  48 }
  49
  50 static void mark_blob_uninteresting(struct blob *blob)
  51 {
  52         if (!blob)
  53                 return;
  54         if (blob->object.flags & UNINTERESTING)
  55                 return;
  56         blob->object.flags |= UNINTERESTING;
  57 }
  58
  59 void mark_tree_uninteresting(struct tree *tree)
  60 {
  61         struct tree_desc desc;
  62         struct name_entry entry;
  63         struct object *obj = &tree->object;
  64
  65         if (!tree)
  66                 return;
  67         if (obj->flags & UNINTERESTING)
  68                 return;
  69         obj->flags |= UNINTERESTING;
  70         if (!has_sha1_file(obj->sha1))
  71                 return;
  72         if (parse_tree(tree) < 0)
  73                 die("bad tree %s", sha1_to_hex(obj->sha1));
  74
  75         init_tree_desc(&desc, tree->buffer, tree->size);
  76         while (tree_entry(&desc, &entry)) {
  77                 switch (object_type(entry.mode)) {
  78                 case OBJ_TREE:
  79                         mark_tree_uninteresting(lookup_tree(entry.sha1));
  80                         break;
  81                 case OBJ_BLOB:
  82                         mark_blob_uninteresting(lookup_blob(entry.sha1));
  83                         break;
  84                 default:
  85                         /* Subproject commit - not in this repository */
  86                         break;
  87                 }
  88         }
  89
  90         /*
  91          * We don't care about the tree any more
  92          * after it has been marked uninteresting.
  93          */
  94         free(tree->buffer);
  95         tree->buffer = NULL;
  96 }
  97
  98 void mark_parents_uninteresting(struct commit *commit)
  99 {
 100         struct commit_list *parents = commit->parents;
 101
 102         while (parents) {
 103                 struct commit *commit = parents->item;
 104                 if (!(commit->object.flags & UNINTERESTING)) {
 105                         commit->object.flags |= UNINTERESTING;
 106
 107                         /*
 108                          * Normally we haven't parsed the parent
 109                          * yet, so we won't have a parent of a parent
 110                          * here. However, it may turn out that we've
 111                          * reached this commit some other way (where it
 112                          * wasn't uninteresting), in which case we need
 113                          * to mark its parents recursively too..
 114                          */
 115                         if (commit->parents)
 116                                 mark_parents_uninteresting(commit);
 117                 }
 118
 119                 /*
 120                  * A missing commit is ok iff its parent is marked
 121                  * uninteresting.
 122                  *
 123                  * We just mark such a thing parsed, so that when
 124                  * it is popped next time around, we won't be trying
 125                  * to parse it and get an error.
 126                  */
 127                 if (!has_sha1_file(commit->object.sha1))
 128                         commit->object.parsed = 1;
 129                 parents = parents->next;
 130         }
 131 }
 132
 133 static void add_pending_object_with_mode(struct rev_info *revs, struct object *obj, const char *name, unsigned mode)
 134 {
 135         if (revs->no_walk && (obj->flags & UNINTERESTING))
 136                 die("object ranges do not make sense when not walking revisions");
 137         if (revs->reflog_info && obj->type == OBJ_COMMIT &&
 138                         add_reflog_for_walk(revs->reflog_info,
 139                                 (struct commit *)obj, name))
 140                 return;
 141         add_object_array_with_mode(obj, name, &revs->pending, mode);
 142 }
 143
 144 void add_pending_object(struct rev_info *revs, struct object *obj, const char *name)
 145 {
 146         add_pending_object_with_mode(revs, obj, name, S_IFINVALID);
 147 }
 148
 149 void add_head_to_pending(struct rev_info *revs)
 150 {
 151         unsigned char sha1[20];
 152         struct object *obj;
 153         if (get_sha1("HEAD", sha1))
 154                 return;
 155         obj = parse_object(sha1);
 156         if (!obj)
 157                 return;
 158         add_pending_object(revs, obj, "HEAD");
 159 }
 160
 161 static struct object *get_reference(struct rev_info *revs, const char *name, const unsigned char *sha1, unsigned int flags)
 162 {
 163         struct object *object;
 164
 165         object = parse_object(sha1);
 166         if (!object)
 167                 die("bad object %s", name);
 168         object->flags |= flags;
 169         return object;
 170 }
 171
 172 static struct commit *handle_commit(struct rev_info *revs, struct object *object, const char *name)
 173 {
 174         unsigned long flags = object->flags;
 175
 176         /*
 177          * Tag object? Look what it points to..
 178          */
 179         while (object->type == OBJ_TAG) {
 180                 struct tag *tag = (struct tag *) object;
 181                 if (revs->tag_objects && !(flags & UNINTERESTING))
 182                         add_pending_object(revs, object, tag->tag);
 183                 if (!tag->tagged)
 184                         die("bad tag");
 185                 object = parse_object(tag->tagged->sha1);
 186                 if (!object) {
 187                         if (flags & UNINTERESTING)
 188                                 return NULL;
 189                         die("bad object %s", sha1_to_hex(tag->tagged->sha1));
 190                 }
 191         }
 192
 193         /*
 194          * Commit object? Just return it, we'll do all the complex
 195          * reachability crud.
 196          */
 197         if (object->type == OBJ_COMMIT) {
 198                 struct commit *commit = (struct commit *)object;
 199                 if (parse_commit(commit) < 0)
 200                         die("unable to parse commit %s", name);
 201                 if (flags & UNINTERESTING) {
 202                         commit->object.flags |= UNINTERESTING;
 203                         mark_parents_uninteresting(commit);
 204                         revs->limited = 1;
 205                 }
 206                 if (revs->show_source && !commit->util)
 207                         commit->util = (void *) name;
 208                 return commit;
 209         }
 210
 211         /*
 212          * Tree object? Either mark it uniniteresting, or add it
 213          * to the list of objects to look at later..
 214          */
 215         if (object->type == OBJ_TREE) {
 216                 struct tree *tree = (struct tree *)object;
 217                 if (!revs->tree_objects)
 218                         return NULL;
 219                 if (flags & UNINTERESTING) {
 220                         mark_tree_uninteresting(tree);
 221                         return NULL;
 222                 }
 223                 add_pending_object(revs, object, "");
 224                 return NULL;
 225         }
 226
 227         /*
 228          * Blob object? You know the drill by now..
 229          */
 230         if (object->type == OBJ_BLOB) {
 231                 struct blob *blob = (struct blob *)object;
 232                 if (!revs->blob_objects)
 233                         return NULL;
 234                 if (flags & UNINTERESTING) {
 235                         mark_blob_uninteresting(blob);
 236                         return NULL;
 237                 }
 238                 add_pending_object(revs, object, "");
 239                 return NULL;
 240         }
 241         die("%s is unknown object", name);
 242 }
 243
 244 static int everybody_uninteresting(struct commit_list *orig)
 245 {
 246         struct commit_list *list = orig;
 247         while (list) {
 248                 struct commit *commit = list->item;
 249                 list = list->next;
 250                 if (commit->object.flags & UNINTERESTING)
 251                         continue;
 252                 return 0;
 253         }
 254         return 1;
 255 }
 256
 257 /*
 258  * The goal is to get REV_TREE_NEW as the result only if the
 259  * diff consists of all '+' (and no other changes), and
 260  * REV_TREE_DIFFERENT otherwise (of course if the trees are
 261  * the same we want REV_TREE_SAME).  That means that once we
 262  * get to REV_TREE_DIFFERENT, we do not have to look any further.
 263  */
 264 static int tree_difference = REV_TREE_SAME;
 265
 266 static void file_add_remove(struct diff_options *options,
 267                     int addremove, unsigned mode,
 268                     const unsigned char *sha1,
 269                     const char *fullpath)
 270 {
 271         int diff = REV_TREE_DIFFERENT;
 272
 273         /*
 274          * Is it an add of a new file? It means that the old tree
 275          * didn't have it at all, so we will turn "REV_TREE_SAME" ->
 276          * "REV_TREE_NEW", but leave any "REV_TREE_DIFFERENT" alone
 277          * (and if it already was "REV_TREE_NEW", we'll keep it
 278          * "REV_TREE_NEW" of course).
 279          */
 280         if (addremove == '+') {
 281                 diff = tree_difference;
 282                 if (diff != REV_TREE_SAME)
 283                         return;
 284                 diff = REV_TREE_NEW;
 285         }
 286         tree_difference = diff;
 287         if (tree_difference == REV_TREE_DIFFERENT)
 288                 DIFF_OPT_SET(options, HAS_CHANGES);
 289 }
 290
 291 static void file_change(struct diff_options *options,
 292                  unsigned old_mode, unsigned new_mode,
 293                  const unsigned char *old_sha1,
 294                  const unsigned char *new_sha1,
 295                  const char *fullpath)
 296 {
 297         tree_difference = REV_TREE_DIFFERENT;
 298         DIFF_OPT_SET(options, HAS_CHANGES);
 299 }
 300
 301 static int rev_compare_tree(struct rev_info *revs, struct commit *parent, struct commit *commit)
 302 {
 303         struct tree *t1 = parent->tree;
 304         struct tree *t2 = commit->tree;
 305
 306         if (!t1)
 307                 return REV_TREE_NEW;
 308
 309         if (revs->simplify_by_decoration) {
 310                 /*
 311                  * If we are simplifying by decoration, then the commit
 312                  * is worth showing if it has a tag pointing at it.
 313                  */
 314                 if (lookup_decoration(&name_decoration, &commit->object))
 315                         return REV_TREE_DIFFERENT;
 316                 /*
 317                  * A commit that is not pointed by a tag is uninteresting
 318                  * if we are not limited by path.  This means that you will
 319                  * see the usual "commits that touch the paths" plus any
 320                  * tagged commit by specifying both --simplify-by-decoration
 321                  * and pathspec.
 322                  */
 323                 if (!revs->prune_data)
 324                         return REV_TREE_SAME;
 325         }
 326         if (!t2)
 327                 return REV_TREE_DIFFERENT;
 328         tree_difference = REV_TREE_SAME;
 329         DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
 330         if (diff_tree_sha1(t1->object.sha1, t2->object.sha1, "",
 331                            &revs->pruning) < 0)
 332                 return REV_TREE_DIFFERENT;
 333         return tree_difference;
 334 }
 335
 336 static int rev_same_tree_as_empty(struct rev_info *revs, struct commit *commit)
 337 {
 338         int retval;
 339         void *tree;
 340         unsigned long size;
 341         struct tree_desc empty, real;
 342         struct tree *t1 = commit->tree;
 343
 344         if (!t1)
 345                 return 0;
 346
 347         tree = read_object_with_reference(t1->object.sha1, tree_type, &size, NULL);
 348         if (!tree)
 349                 return 0;
 350         init_tree_desc(&real, tree, size);
 351         init_tree_desc(&empty, "", 0);
 352
 353         tree_difference = REV_TREE_SAME;
 354         DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
 355         retval = diff_tree(&empty, &real, "", &revs->pruning);
 356         free(tree);
 357
 358         return retval >= 0 && (tree_difference == REV_TREE_SAME);
 359 }
 360
 361 static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
 362 {
 363         struct commit_list **pp, *parent;
 364         int tree_changed = 0, tree_same = 0;
 365
 366         /*
 367          * If we don't do pruning, everything is interesting
 368          */
 369         if (!revs->prune)
 370                 return;
 371
 372         if (!commit->tree)
 373                 return;
 374
 375         if (!commit->parents) {
 376                 if (rev_same_tree_as_empty(revs, commit))
 377                         commit->object.flags |= TREESAME;
 378                 return;
 379         }
 380
 381         /*
 382          * Normal non-merge commit? If we don't want to make the
 383          * history dense, we consider it always to be a change..
 384          */
 385         if (!revs->dense && !commit->parents->next)
 386                 return;
 387
 388         pp = &commit->parents;
 389         while ((parent = *pp) != NULL) {
 390                 struct commit *p = parent->item;
 391
 392                 if (parse_commit(p) < 0)
 393                         die("cannot simplify commit %s (because of %s)",
 394                             sha1_to_hex(commit->object.sha1),
 395                             sha1_to_hex(p->object.sha1));
 396                 switch (rev_compare_tree(revs, p, commit)) {
 397                 case REV_TREE_SAME:
 398                         tree_same = 1;
 399                         if (!revs->simplify_history || (p->object.flags & UNINTERESTING)) {
 400                                 /* Even if a merge with an uninteresting
 401                                  * side branch brought the entire change
 402                                  * we are interested in, we do not want
 403                                  * to lose the other branches of this
 404                                  * merge, so we just keep going.
 405                                  */
 406                                 pp = &parent->next;
 407                                 continue;
 408                         }
 409                         parent->next = NULL;
 410                         commit->parents = parent;
 411                         commit->object.flags |= TREESAME;
 412                         return;
 413
 414                 case REV_TREE_NEW:
 415                         if (revs->remove_empty_trees &&
 416                             rev_same_tree_as_empty(revs, p)) {
 417                                 /* We are adding all the specified
 418                                  * paths from this parent, so the
 419                                  * history beyond this parent is not
 420                                  * interesting.  Remove its parents
 421                                  * (they are grandparents for us).
 422                                  * IOW, we pretend this parent is a
 423                                  * "root" commit.
 424                                  */
 425                                 if (parse_commit(p) < 0)
 426                                         die("cannot simplify commit %s (invalid %s)",
 427                                             sha1_to_hex(commit->object.sha1),
 428                                             sha1_to_hex(p->object.sha1));
 429                                 p->parents = NULL;
 430                         }
 431                 /* fallthrough */
 432                 case REV_TREE_DIFFERENT:
 433                         tree_changed = 1;
 434                         pp = &parent->next;
 435                         continue;
 436                 }
 437                 die("bad tree compare for commit %s", sha1_to_hex(commit->object.sha1));
 438         }
 439         if (tree_changed && !tree_same)
 440                 return;
 441         commit->object.flags |= TREESAME;
 442 }
 443
 444 static void insert_by_date_cached(struct commit *p, struct commit_list **head,
 445                     struct commit_list *cached_base, struct commit_list **cache)
 446 {
 447         struct commit_list *new_entry;
 448
 449         if (cached_base && p->date < cached_base->item->date)
 450                 new_entry = insert_by_date(p, &cached_base->next);
 451         else
 452                 new_entry = insert_by_date(p, head);
 453
 454         if (cache && (!*cache || p->date < (*cache)->item->date))
 455                 *cache = new_entry;
 456 }
 457
 458 static int add_parents_to_list(struct rev_info *revs, struct commit *commit,
 459                     struct commit_list **list, struct commit_list **cache_ptr)
 460 {
 461         struct commit_list *parent = commit->parents;
 462         unsigned left_flag;
 463         struct commit_list *cached_base = cache_ptr ? *cache_ptr : NULL;
 464
 465         if (commit->object.flags & ADDED)
 466                 return 0;
 467         commit->object.flags |= ADDED;
 468
 469         /*
 470          * If the commit is uninteresting, don't try to
 471          * prune parents - we want the maximal uninteresting
 472          * set.
 473          *
 474          * Normally we haven't parsed the parent
 475          * yet, so we won't have a parent of a parent
 476          * here. However, it may turn out that we've
 477          * reached this commit some other way (where it
 478          * wasn't uninteresting), in which case we need
 479          * to mark its parents recursively too..
 480          */
 481         if (commit->object.flags & UNINTERESTING) {
 482                 while (parent) {
 483                         struct commit *p = parent->item;
 484                         parent = parent->next;
 485                         if (p)
 486                                 p->object.flags |= UNINTERESTING;
 487                         if (parse_commit(p) < 0)
 488                                 continue;
 489                         if (p->parents)
 490                                 mark_parents_uninteresting(p);
 491                         if (p->object.flags & SEEN)
 492                                 continue;
 493                         p->object.flags |= SEEN;
 494                         insert_by_date_cached(p, list, cached_base, cache_ptr);
 495                 }
 496                 return 0;
 497         }
 498
 499         /*
 500          * Ok, the commit wasn't uninteresting. Try to
 501          * simplify the commit history and find the parent
 502          * that has no differences in the path set if one exists.
 503          */
 504         try_to_simplify_commit(revs, commit);
 505
 506         if (revs->no_walk)
 507                 return 0;
 508
 509         left_flag = (commit->object.flags & SYMMETRIC_LEFT);
 510
 511         for (parent = commit->parents; parent; parent = parent->next) {
 512                 struct commit *p = parent->item;
 513
 514                 if (parse_commit(p) < 0)
 515                         return -1;
 516                 if (revs->show_source && !p->util)
 517                         p->util = commit->util;
 518                 p->object.flags |= left_flag;
 519                 if (!(p->object.flags & SEEN)) {
 520                         p->object.flags |= SEEN;
 521                         insert_by_date_cached(p, list, cached_base, cache_ptr);
 522                 }
 523                 if (revs->first_parent_only)
 524                         break;
 525         }
 526         return 0;
 527 }
 528
 529 static void cherry_pick_list(struct commit_list *list, struct rev_info *revs)
 530 {
 531         struct commit_list *p;
 532         int left_count = 0, right_count = 0;
 533         int left_first;
 534         struct patch_ids ids;
 535
 536         /* First count the commits on the left and on the right */
 537         for (p = list; p; p = p->next) {
 538                 struct commit *commit = p->item;
 539                 unsigned flags = commit->object.flags;
 540                 if (flags & BOUNDARY)
 541                         ;
 542                 else if (flags & SYMMETRIC_LEFT)
 543                         left_count++;
 544                 else
 545                         right_count++;
 546         }
 547
 548         left_first = left_count < right_count;
 549         init_patch_ids(&ids);
 550         if (revs->diffopt.nr_paths) {
 551                 ids.diffopts.nr_paths = revs->diffopt.nr_paths;
 552                 ids.diffopts.paths = revs->diffopt.paths;
 553                 ids.diffopts.pathlens = revs->diffopt.pathlens;
 554         }
 555
 556         /* Compute patch-ids for one side */
 557         for (p = list; p; p = p->next) {
 558                 struct commit *commit = p->item;
 559                 unsigned flags = commit->object.flags;
 560
 561                 if (flags & BOUNDARY)
 562                         continue;
 563                 /*
 564                  * If we have fewer left, left_first is set and we omit
 565                  * commits on the right branch in this loop.  If we have
 566                  * fewer right, we skip the left ones.
 567                  */
 568                 if (left_first != !!(flags & SYMMETRIC_LEFT))
 569                         continue;
 570                 commit->util = add_commit_patch_id(commit, &ids);
 571         }
 572
 573         /* Check the other side */
 574         for (p = list; p; p = p->next) {
 575                 struct commit *commit = p->item;
 576                 struct patch_id *id;
 577                 unsigned flags = commit->object.flags;
 578
 579                 if (flags & BOUNDARY)
 580                         continue;
 581                 /*
 582                  * If we have fewer left, left_first is set and we omit
 583                  * commits on the left branch in this loop.
 584                  */
 585                 if (left_first == !!(flags & SYMMETRIC_LEFT))
 586                         continue;
 587
 588                 /*
 589                  * Have we seen the same patch id?
 590                  */
 591                 id = has_commit_patch_id(commit, &ids);
 592                 if (!id)
 593                         continue;
 594                 id->seen = 1;
 595                 commit->object.flags |= SHOWN;
 596         }
 597
 598         /* Now check the original side for seen ones */
 599         for (p = list; p; p = p->next) {
 600                 struct commit *commit = p->item;
 601                 struct patch_id *ent;
 602
 603                 ent = commit->util;
 604                 if (!ent)
 605                         continue;
 606                 if (ent->seen)
 607                         commit->object.flags |= SHOWN;
 608                 commit->util = NULL;
 609         }
 610
 611         free_patch_ids(&ids);
 612 }
 613
 614 /* How many extra uninteresting commits we want to see.. */
 615 #define SLOP 5
 616
 617 static int still_interesting(struct commit_list *src, unsigned long date, int slop)
 618 {
 619         /*
 620          * No source list at all? We're definitely done..
 621          */
 622         if (!src)
 623                 return 0;
 624
 625         /*
 626          * Does the destination list contain entries with a date
 627          * before the source list? Definitely _not_ done.
 628          */
 629         if (date < src->item->date)
 630                 return SLOP;
 631
 632         /*
 633          * Does the source list still have interesting commits in
 634          * it? Definitely not done..
 635          */
 636         if (!everybody_uninteresting(src))
 637                 return SLOP;
 638
 639         /* Ok, we're closing in.. */
 640         return slop-1;
 641 }
 642
 643 static int limit_list(struct rev_info *revs)
 644 {
 645         int slop = SLOP;
 646         unsigned long date = ~0ul;
 647         struct commit_list *list = revs->commits;
 648         struct commit_list *newlist = NULL;
 649         struct commit_list **p = &newlist;
 650
 651         while (list) {
 652                 struct commit_list *entry = list;
 653                 struct commit *commit = list->item;
 654                 struct object *obj = &commit->object;
 655                 show_early_output_fn_t show;
 656
 657                 list = list->next;
 658                 free(entry);
 659
 660                 if (revs->max_age != -1 && (commit->date < revs->max_age))
 661                         obj->flags |= UNINTERESTING;
 662                 if (add_parents_to_list(revs, commit, &list, NULL) < 0)
 663                         return -1;
 664                 if (obj->flags & UNINTERESTING) {
 665                         mark_parents_uninteresting(commit);
 666                         if (revs->show_all)
 667                                 p = &commit_list_insert(commit, p)->next;
 668                         slop = still_interesting(list, date, slop);
 669                         if (slop)
 670                                 continue;
 671                         /* If showing all, add the whole pending list to the end */
 672                         if (revs->show_all)
 673                                 *p = list;
 674                         break;
 675                 }
 676                 if (revs->min_age != -1 && (commit->date > revs->min_age))
 677                         continue;
 678                 date = commit->date;
 679                 p = &commit_list_insert(commit, p)->next;
 680
 681                 show = show_early_output;
 682                 if (!show)
 683                         continue;
 684
 685                 show(revs, newlist);
 686                 show_early_output = NULL;
 687         }
 688         if (revs->cherry_pick)
 689                 cherry_pick_list(newlist, revs);
 690
 691         revs->commits = newlist;
 692         return 0;
 693 }
 694
 695 struct all_refs_cb {
 696         int all_flags;
 697         int warned_bad_reflog;
 698         struct rev_info *all_revs;
 699         const char *name_for_errormsg;
 700 };
 701
 702 static int handle_one_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
 703 {
 704         struct all_refs_cb *cb = cb_data;
 705         struct object *object = get_reference(cb->all_revs, path, sha1,
 706                                               cb->all_flags);
 707         add_pending_object(cb->all_revs, object, path);
 708         return 0;
 709 }
 710
 711 static void handle_refs(struct rev_info *revs, unsigned flags,
 712                 int (*for_each)(each_ref_fn, void *))
 713 {
 714         struct all_refs_cb cb;
 715         cb.all_revs = revs;
 716         cb.all_flags = flags;
 717         for_each(handle_one_ref, &cb);
 718 }
 719
 720 static void handle_one_reflog_commit(unsigned char *sha1, void *cb_data)
 721 {
 722         struct all_refs_cb *cb = cb_data;
 723         if (!is_null_sha1(sha1)) {
 724                 struct object *o = parse_object(sha1);
 725                 if (o) {
 726                         o->flags |= cb->all_flags;
 727                         add_pending_object(cb->all_revs, o, "");
 728                 }
 729                 else if (!cb->warned_bad_reflog) {
 730                         warning("reflog of '%s' references pruned commits",
 731                                 cb->name_for_errormsg);
 732                         cb->warned_bad_reflog = 1;
 733                 }
 734         }
 735 }
 736
 737 static int handle_one_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
 738                 const char *email, unsigned long timestamp, int tz,
 739                 const char *message, void *cb_data)
 740 {
 741         handle_one_reflog_commit(osha1, cb_data);
 742         handle_one_reflog_commit(nsha1, cb_data);
 743         return 0;
 744 }
 745
 746 static int handle_one_reflog(const char *path, const unsigned char *sha1, int flag, void *cb_data)
 747 {
 748         struct all_refs_cb *cb = cb_data;
 749         cb->warned_bad_reflog = 0;
 750         cb->name_for_errormsg = path;
 751         for_each_reflog_ent(path, handle_one_reflog_ent, cb_data);
 752         return 0;
 753 }
 754
 755 static void handle_reflog(struct rev_info *revs, unsigned flags)
 756 {
 757         struct all_refs_cb cb;
 758         cb.all_revs = revs;
 759         cb.all_flags = flags;
 760         for_each_reflog(handle_one_reflog, &cb);
 761 }
 762
 763 static int add_parents_only(struct rev_info *revs, const char *arg, int flags)
 764 {
 765         unsigned char sha1[20];
 766         struct object *it;
 767         struct commit *commit;
 768         struct commit_list *parents;
 769
 770         if (*arg == '^') {
 771                 flags ^= UNINTERESTING;
 772                 arg++;
 773         }
 774         if (get_sha1(arg, sha1))
 775                 return 0;
 776         while (1) {
 777                 it = get_reference(revs, arg, sha1, 0);
 778                 if (it->type != OBJ_TAG)
 779                         break;
 780                 if (!((struct tag*)it)->tagged)
 781                         return 0;
 782                 hashcpy(sha1, ((struct tag*)it)->tagged->sha1);
 783         }
 784         if (it->type != OBJ_COMMIT)
 785                 return 0;
 786         commit = (struct commit *)it;
 787         for (parents = commit->parents; parents; parents = parents->next) {
 788                 it = &parents->item->object;
 789                 it->flags |= flags;
 790                 add_pending_object(revs, it, arg);
 791         }
 792         return 1;
 793 }
 794
 795 void init_revisions(struct rev_info *revs, const char *prefix)
 796 {
 797         memset(revs, 0, sizeof(*revs));
 798
 799         revs->abbrev = DEFAULT_ABBREV;
 800         revs->ignore_merges = 1;
 801         revs->simplify_history = 1;
 802         DIFF_OPT_SET(&revs->pruning, RECURSIVE);
 803         DIFF_OPT_SET(&revs->pruning, QUIET);
 804         revs->pruning.add_remove = file_add_remove;
 805         revs->pruning.change = file_change;
 806         revs->lifo = 1;
 807         revs->dense = 1;
 808         revs->prefix = prefix;
 809         revs->max_age = -1;
 810         revs->min_age = -1;
 811         revs->skip_count = -1;
 812         revs->max_count = -1;
 813
 814         revs->commit_format = CMIT_FMT_DEFAULT;
 815
 816         revs->grep_filter.status_only = 1;
 817         revs->grep_filter.pattern_tail = &(revs->grep_filter.pattern_list);
 818         revs->grep_filter.regflags = REG_NEWLINE;
 819
 820         diff_setup(&revs->diffopt);
 821         if (prefix && !revs->diffopt.prefix) {
 822                 revs->diffopt.prefix = prefix;
 823                 revs->diffopt.prefix_length = strlen(prefix);
 824         }
 825 }
 826
 827 static void add_pending_commit_list(struct rev_info *revs,
 828                                     struct commit_list *commit_list,
 829                                     unsigned int flags)
 830 {
 831         while (commit_list) {
 832                 struct object *object = &commit_list->item->object;
 833                 object->flags |= flags;
 834                 add_pending_object(revs, object, sha1_to_hex(object->sha1));
 835                 commit_list = commit_list->next;
 836         }
 837 }
 838
 839 static void prepare_show_merge(struct rev_info *revs)
 840 {
 841         struct commit_list *bases;
 842         struct commit *head, *other;
 843         unsigned char sha1[20];
 844         const char **prune = NULL;
 845         int i, prune_num = 1; /* counting terminating NULL */
 846
 847         if (get_sha1("HEAD", sha1) || !(head = lookup_commit(sha1)))
 848                 die("--merge without HEAD?");
 849         if (get_sha1("MERGE_HEAD", sha1) || !(other = lookup_commit(sha1)))
 850                 die("--merge without MERGE_HEAD?");
 851         add_pending_object(revs, &head->object, "HEAD");
 852         add_pending_object(revs, &other->object, "MERGE_HEAD");
 853         bases = get_merge_bases(head, other, 1);
 854         add_pending_commit_list(revs, bases, UNINTERESTING);
 855         free_commit_list(bases);
 856         head->object.flags |= SYMMETRIC_LEFT;
 857
 858         if (!active_nr)
 859                 read_cache();
 860         for (i = 0; i < active_nr; i++) {
 861                 struct cache_entry *ce = active_cache[i];
 862                 if (!ce_stage(ce))
 863                         continue;
 864                 if (ce_path_match(ce, revs->prune_data)) {
 865                         prune_num++;
 866                         prune = xrealloc(prune, sizeof(*prune) * prune_num);
 867                         prune[prune_num-2] = ce->name;
 868                         prune[prune_num-1] = NULL;
 869                 }
 870                 while ((i+1 < active_nr) &&
 871                        ce_same_name(ce, active_cache[i+1]))
 872                         i++;
 873         }
 874         revs->prune_data = prune;
 875         revs->limited = 1;
 876 }
 877
 878 int handle_revision_arg(const char *arg, struct rev_info *revs,
 879                         int flags,
 880                         int cant_be_filename)
 881 {
 882         unsigned mode;
 883         char *dotdot;
 884         struct object *object;
 885         unsigned char sha1[20];
 886         int local_flags;
 887
 888         dotdot = strstr(arg, "..");
 889         if (dotdot) {
 890                 unsigned char from_sha1[20];
 891                 const char *next = dotdot + 2;
 892                 const char *this = arg;
 893                 int symmetric = *next == '.';
 894                 unsigned int flags_exclude = flags ^ UNINTERESTING;
 895
 896                 *dotdot = 0;
 897                 next += symmetric;
 898
 899                 if (!*next)
 900                         next = "HEAD";
 901                 if (dotdot == arg)
 902                         this = "HEAD";
 903                 if (!get_sha1(this, from_sha1) &&
 904                     !get_sha1(next, sha1)) {
 905                         struct commit *a, *b;
 906                         struct commit_list *exclude;
 907
 908                         a = lookup_commit_reference(from_sha1);
 909                         b = lookup_commit_reference(sha1);
 910                         if (!a || !b) {
 911                                 die(symmetric ?
 912                                     "Invalid symmetric difference expression %s...%s" :
 913                                     "Invalid revision range %s..%s",
 914                                     arg, next);
 915                         }
 916
 917                         if (!cant_be_filename) {
 918                                 *dotdot = '.';
 919                                 verify_non_filename(revs->prefix, arg);
 920                         }
 921
 922                         if (symmetric) {
 923                                 exclude = get_merge_bases(a, b, 1);
 924                                 add_pending_commit_list(revs, exclude,
 925                                                         flags_exclude);
 926                                 free_commit_list(exclude);
 927                                 a->object.flags |= flags | SYMMETRIC_LEFT;
 928                         } else
 929                                 a->object.flags |= flags_exclude;
 930                         b->object.flags |= flags;
 931                         add_pending_object(revs, &a->object, this);
 932                         add_pending_object(revs, &b->object, next);
 933                         return 0;
 934                 }
 935                 *dotdot = '.';
 936         }
 937         dotdot = strstr(arg, "^@");
 938         if (dotdot && !dotdot[2]) {
 939                 *dotdot = 0;
 940                 if (add_parents_only(revs, arg, flags))
 941                         return 0;
 942                 *dotdot = '^';
 943         }
 944         dotdot = strstr(arg, "^!");
 945         if (dotdot && !dotdot[2]) {
 946                 *dotdot = 0;
 947                 if (!add_parents_only(revs, arg, flags ^ UNINTERESTING))
 948                         *dotdot = '^';
 949         }
 950
 951         local_flags = 0;
 952         if (*arg == '^') {
 953                 local_flags = UNINTERESTING;
 954                 arg++;
 955         }
 956         if (get_sha1_with_mode(arg, sha1, &mode))
 957                 return -1;
 958         if (!cant_be_filename)
 959                 verify_non_filename(revs->prefix, arg);
 960         object = get_reference(revs, arg, sha1, flags ^ local_flags);
 961         add_pending_object_with_mode(revs, object, arg, mode);
 962         return 0;
 963 }
 964
 965 void read_revisions_from_stdin(struct rev_info *revs)
 966 {
 967         char line[1000];
 968
 969         while (fgets(line, sizeof(line), stdin) != NULL) {
 970                 int len = strlen(line);
 971                 if (len && line[len - 1] == '\n')
 972                         line[--len] = '\0';
 973                 if (!len)
 974                         break;
 975                 if (line[0] == '-')
 976                         die("options not supported in --stdin mode");
 977                 if (handle_revision_arg(line, revs, 0, 1))
 978                         die("bad revision '%s'", line);
 979         }
 980 }
 981
 982 static void add_grep(struct rev_info *revs, const char *ptn, enum grep_pat_token what)
 983 {
 984         append_grep_pattern(&revs->grep_filter, ptn, "command line", 0, what);
 985 }
 986
 987 static void add_header_grep(struct rev_info *revs, enum grep_header_field field, const char *pattern)
 988 {
 989         append_header_grep_pattern(&revs->grep_filter, field, pattern);
 990 }
 991
 992 static void add_message_grep(struct rev_info *revs, const char *pattern)
 993 {
 994         add_grep(revs, pattern, GREP_PATTERN_BODY);
 995 }
 996
 997 static void add_ignore_packed(struct rev_info *revs, const char *name)
 998 {
 999         int num = ++revs->num_ignore_packed;
1000
1001         revs->ignore_packed = xrealloc(revs->ignore_packed,
1002                                        sizeof(const char *) * (num + 1));
1003         revs->ignore_packed[num-1] = name;
1004         revs->ignore_packed[num] = NULL;
1005 }
1006
1007 static int handle_revision_opt(struct rev_info *revs, int argc, const char **argv,
1008                                int *unkc, const char **unkv)
1009 {
1010         const char *arg = argv[0];
1011
1012         /* pseudo revision arguments */
1013         if (!strcmp(arg, "--all") || !strcmp(arg, "--branches") ||
1014             !strcmp(arg, "--tags") || !strcmp(arg, "--remotes") ||
1015             !strcmp(arg, "--reflog") || !strcmp(arg, "--not") ||
1016             !strcmp(arg, "--no-walk") || !strcmp(arg, "--do-walk"))
1017         {
1018                 unkv[(*unkc)++] = arg;
1019                 return 1;
1020         }
1021
1022         if (!prefixcmp(arg, "--max-count=")) {
1023                 revs->max_count = atoi(arg + 12);
1024         } else if (!prefixcmp(arg, "--skip=")) {
1025                 revs->skip_count = atoi(arg + 7);
1026         } else if ((*arg == '-') && isdigit(arg[1])) {
1027         /* accept -<digit>, like traditional "head" */
1028                 revs->max_count = atoi(arg + 1);
1029         } else if (!strcmp(arg, "-n")) {
1030                 if (argc <= 1)
1031                         return error("-n requires an argument");
1032                 revs->max_count = atoi(argv[1]);
1033                 return 2;
1034         } else if (!prefixcmp(arg, "-n")) {
1035                 revs->max_count = atoi(arg + 2);
1036         } else if (!prefixcmp(arg, "--max-age=")) {
1037                 revs->max_age = atoi(arg + 10);
1038         } else if (!prefixcmp(arg, "--since=")) {
1039                 revs->max_age = approxidate(arg + 8);
1040         } else if (!prefixcmp(arg, "--after=")) {
1041                 revs->max_age = approxidate(arg + 8);
1042         } else if (!prefixcmp(arg, "--min-age=")) {
1043                 revs->min_age = atoi(arg + 10);
1044         } else if (!prefixcmp(arg, "--before=")) {
1045                 revs->min_age = approxidate(arg + 9);
1046         } else if (!prefixcmp(arg, "--until=")) {
1047                 revs->min_age = approxidate(arg + 8);
1048         } else if (!strcmp(arg, "--first-parent")) {
1049                 revs->first_parent_only = 1;
1050         } else if (!strcmp(arg, "-g") || !strcmp(arg, "--walk-reflogs")) {
1051                 init_reflog_walk(&revs->reflog_info);
1052         } else if (!strcmp(arg, "--default")) {
1053                 if (argc <= 1)
1054                         return error("bad --default argument");
1055                 revs->def = argv[1];
1056                 return 2;
1057         } else if (!strcmp(arg, "--merge")) {
1058                 revs->show_merge = 1;
1059         } else if (!strcmp(arg, "--topo-order")) {
1060                 revs->lifo = 1;
1061                 revs->topo_order = 1;
1062         } else if (!strcmp(arg, "--simplify-merges")) {
1063                 revs->simplify_merges = 1;
1064                 revs->rewrite_parents = 1;
1065                 revs->simplify_history = 0;
1066                 revs->limited = 1;
1067         } else if (!strcmp(arg, "--simplify-by-decoration")) {
1068                 revs->simplify_merges = 1;
1069                 revs->rewrite_parents = 1;
1070                 revs->simplify_history = 0;
1071                 revs->simplify_by_decoration = 1;
1072                 revs->limited = 1;
1073                 revs->prune = 1;
1074                 load_ref_decorations();
1075         } else if (!strcmp(arg, "--date-order")) {
1076                 revs->lifo = 0;
1077                 revs->topo_order = 1;
1078         } else if (!prefixcmp(arg, "--early-output")) {
1079                 int count = 100;
1080                 switch (arg[14]) {
1081                 case '=':
1082                         count = atoi(arg+15);
1083                         /* Fallthrough */
1084                 case 0:
1085                         revs->topo_order = 1;
1086                        revs->early_output = count;
1087                 }
1088         } else if (!strcmp(arg, "--parents")) {
1089                 revs->rewrite_parents = 1;
1090                 revs->print_parents = 1;
1091         } else if (!strcmp(arg, "--dense")) {
1092                 revs->dense = 1;
1093         } else if (!strcmp(arg, "--sparse")) {
1094                 revs->dense = 0;
1095         } else if (!strcmp(arg, "--show-all")) {
1096                 revs->show_all = 1;
1097         } else if (!strcmp(arg, "--remove-empty")) {
1098                 revs->remove_empty_trees = 1;
1099         } else if (!strcmp(arg, "--no-merges")) {
1100                 revs->no_merges = 1;
1101         } else if (!strcmp(arg, "--boundary")) {
1102                 revs->boundary = 1;
1103         } else if (!strcmp(arg, "--left-right")) {
1104                 revs->left_right = 1;
1105         } else if (!strcmp(arg, "--cherry-pick")) {
1106                 revs->cherry_pick = 1;
1107                 revs->limited = 1;
1108         } else if (!strcmp(arg, "--objects")) {
1109                 revs->tag_objects = 1;
1110                 revs->tree_objects = 1;
1111                 revs->blob_objects = 1;
1112         } else if (!strcmp(arg, "--objects-edge")) {
1113                 revs->tag_objects = 1;
1114                 revs->tree_objects = 1;
1115                 revs->blob_objects = 1;
1116                 revs->edge_hint = 1;
1117         } else if (!strcmp(arg, "--unpacked")) {
1118                 revs->unpacked = 1;
1119                 free(revs->ignore_packed);
1120                 revs->ignore_packed = NULL;
1121                 revs->num_ignore_packed = 0;
1122         } else if (!prefixcmp(arg, "--unpacked=")) {
1123                 revs->unpacked = 1;
1124                 add_ignore_packed(revs, arg+11);
1125         } else if (!strcmp(arg, "-r")) {
1126                 revs->diff = 1;
1127                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1128         } else if (!strcmp(arg, "-t")) {
1129                 revs->diff = 1;
1130                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1131                 DIFF_OPT_SET(&revs->diffopt, TREE_IN_RECURSIVE);
1132         } else if (!strcmp(arg, "-m")) {
1133                 revs->ignore_merges = 0;
1134         } else if (!strcmp(arg, "-c")) {
1135                 revs->diff = 1;
1136                 revs->dense_combined_merges = 0;
1137                 revs->combine_merges = 1;
1138         } else if (!strcmp(arg, "--cc")) {
1139                 revs->diff = 1;
1140                 revs->dense_combined_merges = 1;
1141                 revs->combine_merges = 1;
1142         } else if (!strcmp(arg, "-v")) {
1143                 revs->verbose_header = 1;
1144         } else if (!strcmp(arg, "--pretty")) {
1145                 revs->verbose_header = 1;
1146                 get_commit_format(arg+8, revs);
1147         } else if (!prefixcmp(arg, "--pretty=")) {
1148                 revs->verbose_header = 1;
1149                 get_commit_format(arg+9, revs);
1150         } else if (!strcmp(arg, "--graph")) {
1151                 revs->topo_order = 1;
1152                 revs->rewrite_parents = 1;
1153                 revs->graph = graph_init(revs);
1154         } else if (!strcmp(arg, "--root")) {
1155                 revs->show_root_diff = 1;
1156         } else if (!strcmp(arg, "--no-commit-id")) {
1157                 revs->no_commit_id = 1;
1158         } else if (!strcmp(arg, "--always")) {
1159                 revs->always_show_header = 1;
1160         } else if (!strcmp(arg, "--no-abbrev")) {
1161                 revs->abbrev = 0;
1162         } else if (!strcmp(arg, "--abbrev")) {
1163                 revs->abbrev = DEFAULT_ABBREV;
1164         } else if (!prefixcmp(arg, "--abbrev=")) {
1165                 revs->abbrev = strtoul(arg + 9, NULL, 10);
1166                 if (revs->abbrev < MINIMUM_ABBREV)
1167                         revs->abbrev = MINIMUM_ABBREV;
1168                 else if (revs->abbrev > 40)
1169                         revs->abbrev = 40;
1170         } else if (!strcmp(arg, "--abbrev-commit")) {
1171                 revs->abbrev_commit = 1;
1172         } else if (!strcmp(arg, "--full-diff")) {
1173                 revs->diff = 1;
1174                 revs->full_diff = 1;
1175         } else if (!strcmp(arg, "--full-history")) {
1176                 revs->simplify_history = 0;
1177         } else if (!strcmp(arg, "--relative-date")) {
1178                 revs->date_mode = DATE_RELATIVE;
1179         } else if (!strncmp(arg, "--date=", 7)) {
1180                 revs->date_mode = parse_date_format(arg + 7);
1181         } else if (!strcmp(arg, "--log-size")) {
1182                 revs->show_log_size = 1;
1183         }
1184         /*
1185          * Grepping the commit log
1186          */
1187         else if (!prefixcmp(arg, "--author=")) {
1188                 add_header_grep(revs, GREP_HEADER_AUTHOR, arg+9);
1189         } else if (!prefixcmp(arg, "--committer=")) {
1190                 add_header_grep(revs, GREP_HEADER_COMMITTER, arg+12);
1191         } else if (!prefixcmp(arg, "--grep=")) {
1192                 add_message_grep(revs, arg+7);
1193         } else if (!strcmp(arg, "--extended-regexp") || !strcmp(arg, "-E")) {
1194                 revs->grep_filter.regflags |= REG_EXTENDED;
1195         } else if (!strcmp(arg, "--regexp-ignore-case") || !strcmp(arg, "-i")) {
1196                 revs->grep_filter.regflags |= REG_ICASE;
1197         } else if (!strcmp(arg, "--fixed-strings") || !strcmp(arg, "-F")) {
1198                 revs->grep_filter.fixed = 1;
1199         } else if (!strcmp(arg, "--all-match")) {
1200                 revs->grep_filter.all_match = 1;
1201         } else if (!prefixcmp(arg, "--encoding=")) {
1202                 arg += 11;
1203                 if (strcmp(arg, "none"))
1204                         git_log_output_encoding = xstrdup(arg);
1205                 else
1206                         git_log_output_encoding = "";
1207         } else if (!strcmp(arg, "--reverse")) {
1208                 revs->reverse ^= 1;
1209         } else if (!strcmp(arg, "--children")) {
1210                 revs->children.name = "children";
1211                 revs->limited = 1;
1212         } else {
1213                 int opts = diff_opt_parse(&revs->diffopt, argv, argc);
1214                 if (!opts)
1215                         unkv[(*unkc)++] = arg;
1216                 return opts;
1217         }
1218
1219         return 1;
1220 }
1221
1222 void parse_revision_opt(struct rev_info *revs, struct parse_opt_ctx_t *ctx,
1223                         const struct option *options,
1224                         const char * const usagestr[])
1225 {
1226         int n = handle_revision_opt(revs, ctx->argc, ctx->argv,
1227                                     &ctx->cpidx, ctx->out);
1228         if (n <= 0) {
1229                 error("unknown option `%s'", ctx->argv[0]);
1230                 usage_with_options(usagestr, options);
1231         }
1232         ctx->argv += n;
1233         ctx->argc -= n;
1234 }
1235
1236 /*
1237  * Parse revision information, filling in the "rev_info" structure,
1238  * and removing the used arguments from the argument list.
1239  *
1240  * Returns the number of arguments left that weren't recognized
1241  * (which are also moved to the head of the argument list)
1242  */
1243 int setup_revisions(int argc, const char **argv, struct rev_info *revs, const char *def)
1244 {
1245         int i, flags, left, seen_dashdash;
1246
1247         /* First, search for "--" */
1248         seen_dashdash = 0;
1249         for (i = 1; i < argc; i++) {
1250                 const char *arg = argv[i];
1251                 if (strcmp(arg, "--"))
1252                         continue;
1253                 argv[i] = NULL;
1254                 argc = i;
1255                 if (argv[i + 1])
1256                         revs->prune_data = get_pathspec(revs->prefix, argv + i + 1);
1257                 seen_dashdash = 1;
1258                 break;
1259         }
1260
1261         /* Second, deal with arguments and options */
1262         flags = 0;
1263         for (left = i = 1; i < argc; i++) {
1264                 const char *arg = argv[i];
1265                 if (*arg == '-') {
1266                         int opts;
1267
1268                         if (!strcmp(arg, "--all")) {
1269                                 handle_refs(revs, flags, for_each_ref);
1270                                 handle_refs(revs, flags, head_ref);
1271                                 continue;
1272                         }
1273                         if (!strcmp(arg, "--branches")) {
1274                                 handle_refs(revs, flags, for_each_branch_ref);
1275                                 continue;
1276                         }
1277                         if (!strcmp(arg, "--tags")) {
1278                                 handle_refs(revs, flags, for_each_tag_ref);
1279                                 continue;
1280                         }
1281                         if (!strcmp(arg, "--remotes")) {
1282                                 handle_refs(revs, flags, for_each_remote_ref);
1283                                 continue;
1284                         }
1285                         if (!strcmp(arg, "--reflog")) {
1286                                 handle_reflog(revs, flags);
1287                                 continue;
1288                         }
1289                         if (!strcmp(arg, "--not")) {
1290                                 flags ^= UNINTERESTING;
1291                                 continue;
1292                         }
1293                         if (!strcmp(arg, "--no-walk")) {
1294                                 revs->no_walk = 1;
1295                                 continue;
1296                         }
1297                         if (!strcmp(arg, "--do-walk")) {
1298                                 revs->no_walk = 0;
1299                                 continue;
1300                         }
1301
1302                         opts = handle_revision_opt(revs, argc - i, argv + i, &left, argv);
1303                         if (opts > 0) {
1304                                 i += opts - 1;
1305                                 continue;
1306                         }
1307                         if (opts < 0)
1308                                 exit(128);
1309                         continue;
1310                 }
1311
1312                 if (handle_revision_arg(arg, revs, flags, seen_dashdash)) {
1313                         int j;
1314                         if (seen_dashdash || *arg == '^')
1315                                 die("bad revision '%s'", arg);
1316
1317                         /* If we didn't have a "--":
1318                          * (1) all filenames must exist;
1319                          * (2) all rev-args must not be interpretable
1320                          *     as a valid filename.
1321                          * but the latter we have checked in the main loop.
1322                          */
1323                         for (j = i; j < argc; j++)
1324                                 verify_filename(revs->prefix, argv[j]);
1325
1326                         revs->prune_data = get_pathspec(revs->prefix,
1327                                                         argv + i);
1328                         break;
1329                 }
1330         }
1331
1332         if (revs->def == NULL)
1333                 revs->def = def;
1334         if (revs->show_merge)
1335                 prepare_show_merge(revs);
1336         if (revs->def && !revs->pending.nr) {
1337                 unsigned char sha1[20];
1338                 struct object *object;
1339                 unsigned mode;
1340                 if (get_sha1_with_mode(revs->def, sha1, &mode))
1341                         die("bad default revision '%s'", revs->def);
1342                 object = get_reference(revs, revs->def, sha1, 0);
1343                 add_pending_object_with_mode(revs, object, revs->def, mode);
1344         }
1345
1346         /* Did the user ask for any diff output? Run the diff! */
1347         if (revs->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT)
1348                 revs->diff = 1;
1349
1350         /* Pickaxe, diff-filter and rename following need diffs */
1351         if (revs->diffopt.pickaxe ||
1352             revs->diffopt.filter ||
1353             DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1354                 revs->diff = 1;
1355
1356         if (revs->topo_order)
1357                 revs->limited = 1;
1358
1359         if (revs->prune_data) {
1360                 diff_tree_setup_paths(revs->prune_data, &revs->pruning);
1361                 /* Can't prune commits with rename following: the paths change.. */
1362                 if (!DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1363                         revs->prune = 1;
1364                 if (!revs->full_diff)
1365                         diff_tree_setup_paths(revs->prune_data, &revs->diffopt);
1366         }
1367         if (revs->combine_merges) {
1368                 revs->ignore_merges = 0;
1369                 if (revs->dense_combined_merges && !revs->diffopt.output_format)
1370                         revs->diffopt.output_format = DIFF_FORMAT_PATCH;
1371         }
1372         revs->diffopt.abbrev = revs->abbrev;
1373         if (diff_setup_done(&revs->diffopt) < 0)
1374                 die("diff_setup_done failed");
1375
1376         compile_grep_patterns(&revs->grep_filter);
1377
1378         if (revs->reverse && revs->reflog_info)
1379                 die("cannot combine --reverse with --walk-reflogs");
1380         if (revs->rewrite_parents && revs->children.name)
1381                 die("cannot combine --parents and --children");
1382
1383         /*
1384          * Limitations on the graph functionality
1385          */
1386         if (revs->reverse && revs->graph)
1387                 die("cannot combine --reverse with --graph");
1388
1389         if (revs->reflog_info && revs->graph)
1390                 die("cannot combine --walk-reflogs with --graph");
1391
1392         return left;
1393 }
1394
1395 static void add_child(struct rev_info *revs, struct commit *parent, struct commit *child)
1396 {
1397         struct commit_list *l = xcalloc(1, sizeof(*l));
1398
1399         l->item = child;
1400         l->next = add_decoration(&revs->children, &parent->object, l);
1401 }
1402
1403 static int remove_duplicate_parents(struct commit *commit)
1404 {
1405         struct commit_list **pp, *p;
1406         int surviving_parents;
1407
1408         /* Examine existing parents while marking ones we have seen... */
1409         pp = &commit->parents;
1410         while ((p = *pp) != NULL) {
1411                 struct commit *parent = p->item;
1412                 if (parent->object.flags & TMP_MARK) {
1413                         *pp = p->next;
1414                         continue;
1415                 }
1416                 parent->object.flags |= TMP_MARK;
1417                 pp = &p->next;
1418         }
1419         /* count them while clearing the temporary mark */
1420         surviving_parents = 0;
1421         for (p = commit->parents; p; p = p->next) {
1422                 p->item->object.flags &= ~TMP_MARK;
1423                 surviving_parents++;
1424         }
1425         return surviving_parents;
1426 }
1427
1428 struct merge_simplify_state {
1429         struct commit *simplified;
1430 };
1431
1432 static struct merge_simplify_state *locate_simplify_state(struct rev_info *revs, struct commit *commit)
1433 {
1434         struct merge_simplify_state *st;
1435
1436         st = lookup_decoration(&revs->merge_simplification, &commit->object);
1437         if (!st) {
1438                 st = xcalloc(1, sizeof(*st));
1439                 add_decoration(&revs->merge_simplification, &commit->object, st);
1440         }
1441         return st;
1442 }
1443
1444 static struct commit_list **simplify_one(struct rev_info *revs, struct commit *commit, struct commit_list **tail)
1445 {
1446         struct commit_list *p;
1447         struct merge_simplify_state *st, *pst;
1448         int cnt;
1449
1450         st = locate_simplify_state(revs, commit);
1451
1452         /*
1453          * Have we handled this one?
1454          */
1455         if (st->simplified)
1456                 return tail;
1457
1458         /*
1459          * An UNINTERESTING commit simplifies to itself, so does a
1460          * root commit.  We do not rewrite parents of such commit
1461          * anyway.
1462          */
1463         if ((commit->object.flags & UNINTERESTING) || !commit->parents) {
1464                 st->simplified = commit;
1465                 return tail;
1466         }
1467
1468         /*
1469          * Do we know what commit all of our parents should be rewritten to?
1470          * Otherwise we are not ready to rewrite this one yet.
1471          */
1472         for (cnt = 0, p = commit->parents; p; p = p->next) {
1473                 pst = locate_simplify_state(revs, p->item);
1474                 if (!pst->simplified) {
1475                         tail = &commit_list_insert(p->item, tail)->next;
1476                         cnt++;
1477                 }
1478         }
1479         if (cnt) {
1480                 tail = &commit_list_insert(commit, tail)->next;
1481                 return tail;
1482         }
1483
1484         /*
1485          * Rewrite our list of parents.
1486          */
1487         for (p = commit->parents; p; p = p->next) {
1488                 pst = locate_simplify_state(revs, p->item);
1489                 p->item = pst->simplified;
1490         }
1491         cnt = remove_duplicate_parents(commit);
1492
1493         /*
1494          * It is possible that we are a merge and one side branch
1495          * does not have any commit that touches the given paths;
1496          * in such a case, the immediate parents will be rewritten
1497          * to different commits.
1498          *
1499          *      o----X          X: the commit we are looking at;
1500          *     /    /           o: a commit that touches the paths;
1501          * ---o----'
1502          *
1503          * Further reduce the parents by removing redundant parents.
1504          */
1505         if (1 < cnt) {
1506                 struct commit_list *h = reduce_heads(commit->parents);
1507                 cnt = commit_list_count(h);
1508                 free_commit_list(commit->parents);
1509                 commit->parents = h;
1510         }
1511
1512         /*
1513          * A commit simplifies to itself if it is a root, if it is
1514          * UNINTERESTING, if it touches the given paths, or if it is a
1515          * merge and its parents simplifies to more than one commits
1516          * (the first two cases are already handled at the beginning of
1517          * this function).
1518          *
1519          * Otherwise, it simplifies to what its sole parent simplifies to.
1520          */
1521         if (!cnt ||
1522             (commit->object.flags & UNINTERESTING) ||
1523             !(commit->object.flags & TREESAME) ||
1524             (1 < cnt))
1525                 st->simplified = commit;
1526         else {
1527                 pst = locate_simplify_state(revs, commit->parents->item);
1528                 st->simplified = pst->simplified;
1529         }
1530         return tail;
1531 }
1532
1533 static void simplify_merges(struct rev_info *revs)
1534 {
1535         struct commit_list *list;
1536         struct commit_list *yet_to_do, **tail;
1537
1538         if (!revs->topo_order)
1539                 sort_in_topological_order(&revs->commits, revs->lifo);
1540         if (!revs->prune)
1541                 return;
1542
1543         /* feed the list reversed */
1544         yet_to_do = NULL;
1545         for (list = revs->commits; list; list = list->next)
1546                 commit_list_insert(list->item, &yet_to_do);
1547         while (yet_to_do) {
1548                 list = yet_to_do;
1549                 yet_to_do = NULL;
1550                 tail = &yet_to_do;
1551                 while (list) {
1552                         struct commit *commit = list->item;
1553                         struct commit_list *next = list->next;
1554                         free(list);
1555                         list = next;
1556                         tail = simplify_one(revs, commit, tail);
1557                 }
1558         }
1559
1560         /* clean up the result, removing the simplified ones */
1561         list = revs->commits;
1562         revs->commits = NULL;
1563         tail = &revs->commits;
1564         while (list) {
1565                 struct commit *commit = list->item;
1566                 struct commit_list *next = list->next;
1567                 struct merge_simplify_state *st;
1568                 free(list);
1569                 list = next;
1570                 st = locate_simplify_state(revs, commit);
1571                 if (st->simplified == commit)
1572                         tail = &commit_list_insert(commit, tail)->next;
1573         }
1574 }
1575
1576 static void set_children(struct rev_info *revs)
1577 {
1578         struct commit_list *l;
1579         for (l = revs->commits; l; l = l->next) {
1580                 struct commit *commit = l->item;
1581                 struct commit_list *p;
1582
1583                 for (p = commit->parents; p; p = p->next)
1584                         add_child(revs, p->item, commit);
1585         }
1586 }
1587
1588 int prepare_revision_walk(struct rev_info *revs)
1589 {
1590         int nr = revs->pending.nr;
1591         struct object_array_entry *e, *list;
1592
1593         e = list = revs->pending.objects;
1594         revs->pending.nr = 0;
1595         revs->pending.alloc = 0;
1596         revs->pending.objects = NULL;
1597         while (--nr >= 0) {
1598                 struct commit *commit = handle_commit(revs, e->item, e->name);
1599                 if (commit) {
1600                         if (!(commit->object.flags & SEEN)) {
1601                                 commit->object.flags |= SEEN;
1602                                 insert_by_date(commit, &revs->commits);
1603                         }
1604                 }
1605                 e++;
1606         }
1607         free(list);
1608
1609         if (revs->no_walk)
1610                 return 0;
1611         if (revs->limited)
1612                 if (limit_list(revs) < 0)
1613                         return -1;
1614         if (revs->topo_order)
1615                 sort_in_topological_order(&revs->commits, revs->lifo);
1616         if (revs->simplify_merges)
1617                 simplify_merges(revs);
1618         if (revs->children.name)
1619                 set_children(revs);
1620         return 0;
1621 }
1622
1623 enum rewrite_result {
1624         rewrite_one_ok,
1625         rewrite_one_noparents,
1626         rewrite_one_error,
1627 };
1628
1629 static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp)
1630 {
1631         struct commit_list *cache = NULL;
1632
1633         for (;;) {
1634                 struct commit *p = *pp;
1635                 if (!revs->limited)
1636                         if (add_parents_to_list(revs, p, &revs->commits, &cache) < 0)
1637                                 return rewrite_one_error;
1638                 if (p->parents && p->parents->next)
1639                         return rewrite_one_ok;
1640                 if (p->object.flags & UNINTERESTING)
1641                         return rewrite_one_ok;
1642                 if (!(p->object.flags & TREESAME))
1643                         return rewrite_one_ok;
1644                 if (!p->parents)
1645                         return rewrite_one_noparents;
1646                 *pp = p->parents->item;
1647         }
1648 }
1649
1650 static int rewrite_parents(struct rev_info *revs, struct commit *commit)
1651 {
1652         struct commit_list **pp = &commit->parents;
1653         while (*pp) {
1654                 struct commit_list *parent = *pp;
1655                 switch (rewrite_one(revs, &parent->item)) {
1656                 case rewrite_one_ok:
1657                         break;
1658                 case rewrite_one_noparents:
1659                         *pp = parent->next;
1660                         continue;
1661                 case rewrite_one_error:
1662                         return -1;
1663                 }
1664                 pp = &parent->next;
1665         }
1666         remove_duplicate_parents(commit);
1667         return 0;
1668 }
1669
1670 static int commit_match(struct commit *commit, struct rev_info *opt)
1671 {
1672         if (!opt->grep_filter.pattern_list)
1673                 return 1;
1674         return grep_buffer(&opt->grep_filter,
1675                            NULL, /* we say nothing, not even filename */
1676                            commit->buffer, strlen(commit->buffer));
1677 }
1678
1679 static inline int want_ancestry(struct rev_info *revs)
1680 {
1681         return (revs->rewrite_parents || revs->children.name);
1682 }
1683
1684 enum commit_action simplify_commit(struct rev_info *revs, struct commit *commit)
1685 {
1686         if (commit->object.flags & SHOWN)
1687                 return commit_ignore;
1688         if (revs->unpacked && has_sha1_pack(commit->object.sha1, revs->ignore_packed))
1689                 return commit_ignore;
1690         if (revs->show_all)
1691                 return commit_show;
1692         if (commit->object.flags & UNINTERESTING)
1693                 return commit_ignore;
1694         if (revs->min_age != -1 && (commit->date > revs->min_age))
1695                 return commit_ignore;
1696         if (revs->no_merges && commit->parents && commit->parents->next)
1697                 return commit_ignore;
1698         if (!commit_match(commit, revs))
1699                 return commit_ignore;
1700         if (revs->prune && revs->dense) {
1701                 /* Commit without changes? */
1702                 if (commit->object.flags & TREESAME) {
1703                         /* drop merges unless we want parenthood */
1704                         if (!want_ancestry(revs))
1705                                 return commit_ignore;
1706                         /* non-merge - always ignore it */
1707                         if (!commit->parents || !commit->parents->next)
1708                                 return commit_ignore;
1709                 }
1710                 if (want_ancestry(revs) && rewrite_parents(revs, commit) < 0)
1711                         return commit_error;
1712         }
1713         return commit_show;
1714 }
1715
1716 static struct commit *get_revision_1(struct rev_info *revs)
1717 {
1718         if (!revs->commits)
1719                 return NULL;
1720
1721         do {
1722                 struct commit_list *entry = revs->commits;
1723                 struct commit *commit = entry->item;
1724
1725                 revs->commits = entry->next;
1726                 free(entry);
1727
1728                 if (revs->reflog_info)
1729                         fake_reflog_parent(revs->reflog_info, commit);
1730
1731                 /*
1732                  * If we haven't done the list limiting, we need to look at
1733                  * the parents here. We also need to do the date-based limiting
1734                  * that we'd otherwise have done in limit_list().
1735                  */
1736                 if (!revs->limited) {
1737                         if (revs->max_age != -1 &&
1738                             (commit->date < revs->max_age))
1739                                 continue;
1740                         if (add_parents_to_list(revs, commit, &revs->commits, NULL) < 0)
1741                                 die("Failed to traverse parents of commit %s",
1742                                     sha1_to_hex(commit->object.sha1));
1743                 }
1744
1745                 switch (simplify_commit(revs, commit)) {
1746                 case commit_ignore:
1747                         continue;
1748                 case commit_error:
1749                         die("Failed to simplify parents of commit %s",
1750                             sha1_to_hex(commit->object.sha1));
1751                 default:
1752                         return commit;
1753                 }
1754         } while (revs->commits);
1755         return NULL;
1756 }
1757
1758 static void gc_boundary(struct object_array *array)
1759 {
1760         unsigned nr = array->nr;
1761         unsigned alloc = array->alloc;
1762         struct object_array_entry *objects = array->objects;
1763
1764         if (alloc <= nr) {
1765                 unsigned i, j;
1766                 for (i = j = 0; i < nr; i++) {
1767                         if (objects[i].item->flags & SHOWN)
1768                                 continue;
1769                         if (i != j)
1770                                 objects[j] = objects[i];
1771                         j++;
1772                 }
1773                 for (i = j; i < nr; i++)
1774                         objects[i].item = NULL;
1775                 array->nr = j;
1776         }
1777 }
1778
1779 static void create_boundary_commit_list(struct rev_info *revs)
1780 {
1781         unsigned i;
1782         struct commit *c;
1783         struct object_array *array = &revs->boundary_commits;
1784         struct object_array_entry *objects = array->objects;
1785
1786         /*
1787          * If revs->commits is non-NULL at this point, an error occurred in
1788          * get_revision_1().  Ignore the error and continue printing the
1789          * boundary commits anyway.  (This is what the code has always
1790          * done.)
1791          */
1792         if (revs->commits) {
1793                 free_commit_list(revs->commits);
1794                 revs->commits = NULL;
1795         }
1796
1797         /*
1798          * Put all of the actual boundary commits from revs->boundary_commits
1799          * into revs->commits
1800          */
1801         for (i = 0; i < array->nr; i++) {
1802                 c = (struct commit *)(objects[i].item);
1803                 if (!c)
1804                         continue;
1805                 if (!(c->object.flags & CHILD_SHOWN))
1806                         continue;
1807                 if (c->object.flags & (SHOWN | BOUNDARY))
1808                         continue;
1809                 c->object.flags |= BOUNDARY;
1810                 commit_list_insert(c, &revs->commits);
1811         }
1812
1813         /*
1814          * If revs->topo_order is set, sort the boundary commits
1815          * in topological order
1816          */
1817         sort_in_topological_order(&revs->commits, revs->lifo);
1818 }
1819
1820 static struct commit *get_revision_internal(struct rev_info *revs)
1821 {
1822         struct commit *c = NULL;
1823         struct commit_list *l;
1824
1825         if (revs->boundary == 2) {
1826                 /*
1827                  * All of the normal commits have already been returned,
1828                  * and we are now returning boundary commits.
1829                  * create_boundary_commit_list() has populated
1830                  * revs->commits with the remaining commits to return.
1831                  */
1832                 c = pop_commit(&revs->commits);
1833                 if (c)
1834                         c->object.flags |= SHOWN;
1835                 return c;
1836         }
1837
1838         /*
1839          * Now pick up what they want to give us
1840          */
1841         c = get_revision_1(revs);
1842         if (c) {
1843                 while (0 < revs->skip_count) {
1844                         revs->skip_count--;
1845                         c = get_revision_1(revs);
1846                         if (!c)
1847                                 break;
1848                 }
1849         }
1850
1851         /*
1852          * Check the max_count.
1853          */
1854         switch (revs->max_count) {
1855         case -1:
1856                 break;
1857         case 0:
1858                 c = NULL;
1859                 break;
1860         default:
1861                 revs->max_count--;
1862         }
1863
1864         if (c)
1865                 c->object.flags |= SHOWN;
1866
1867         if (!revs->boundary) {
1868                 return c;
1869         }
1870
1871         if (!c) {
1872                 /*
1873                  * get_revision_1() runs out the commits, and
1874                  * we are done computing the boundaries.
1875                  * switch to boundary commits output mode.
1876                  */
1877                 revs->boundary = 2;
1878
1879                 /*
1880                  * Update revs->commits to contain the list of
1881                  * boundary commits.
1882                  */
1883                 create_boundary_commit_list(revs);
1884
1885                 return get_revision_internal(revs);
1886         }
1887
1888         /*
1889          * boundary commits are the commits that are parents of the
1890          * ones we got from get_revision_1() but they themselves are
1891          * not returned from get_revision_1().  Before returning
1892          * 'c', we need to mark its parents that they could be boundaries.
1893          */
1894
1895         for (l = c->parents; l; l = l->next) {
1896                 struct object *p;
1897                 p = &(l->item->object);
1898                 if (p->flags & (CHILD_SHOWN | SHOWN))
1899                         continue;
1900                 p->flags |= CHILD_SHOWN;
1901                 gc_boundary(&revs->boundary_commits);
1902                 add_object_array(p, NULL, &revs->boundary_commits);
1903         }
1904
1905         return c;
1906 }
1907
1908 struct commit *get_revision(struct rev_info *revs)
1909 {
1910         struct commit *c;
1911         struct commit_list *reversed;
1912
1913         if (revs->reverse) {
1914                 reversed = NULL;
1915                 while ((c = get_revision_internal(revs))) {
1916                         commit_list_insert(c, &reversed);
1917                 }
1918                 revs->commits = reversed;
1919                 revs->reverse = 0;
1920                 revs->reverse_output_stage = 1;
1921         }
1922
1923         if (revs->reverse_output_stage)
1924                 return pop_commit(&revs->commits);
1925
1926         c = get_revision_internal(revs);
1927         if (c && revs->graph)
1928                 graph_update(revs->graph, c);
1929         return c;
1930 }