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