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 char *path_name(const struct name_path *path, const char *name)
  19 {
  20         const 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                 revs->no_walk = 0;
 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 uninteresting, 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), REV_TREE_OLD
 260  * if the whole diff is removal of old data, and otherwise
 261  * REV_TREE_DIFFERENT (of course if the trees are the same we
 262  * want REV_TREE_SAME).
 263  * That means that once we get to REV_TREE_DIFFERENT, we do not
 264  * have to look any further.
 265  */
 266 static int tree_difference = REV_TREE_SAME;
 267
 268 static void file_add_remove(struct diff_options *options,
 269                     int addremove, unsigned mode,
 270                     const unsigned char *sha1,
 271                     const char *fullpath)
 272 {
 273         int diff = addremove == '+' ? REV_TREE_NEW : REV_TREE_OLD;
 274
 275         tree_difference |= diff;
 276         if (tree_difference == REV_TREE_DIFFERENT)
 277                 DIFF_OPT_SET(options, HAS_CHANGES);
 278 }
 279
 280 static void file_change(struct diff_options *options,
 281                  unsigned old_mode, unsigned new_mode,
 282                  const unsigned char *old_sha1,
 283                  const unsigned char *new_sha1,
 284                  const char *fullpath)
 285 {
 286         tree_difference = REV_TREE_DIFFERENT;
 287         DIFF_OPT_SET(options, HAS_CHANGES);
 288 }
 289
 290 static int rev_compare_tree(struct rev_info *revs, struct commit *parent, struct commit *commit)
 291 {
 292         struct tree *t1 = parent->tree;
 293         struct tree *t2 = commit->tree;
 294
 295         if (!t1)
 296                 return REV_TREE_NEW;
 297         if (!t2)
 298                 return REV_TREE_OLD;
 299
 300         if (revs->simplify_by_decoration) {
 301                 /*
 302                  * If we are simplifying by decoration, then the commit
 303                  * is worth showing if it has a tag pointing at it.
 304                  */
 305                 if (lookup_decoration(&name_decoration, &commit->object))
 306                         return REV_TREE_DIFFERENT;
 307                 /*
 308                  * A commit that is not pointed by a tag is uninteresting
 309                  * if we are not limited by path.  This means that you will
 310                  * see the usual "commits that touch the paths" plus any
 311                  * tagged commit by specifying both --simplify-by-decoration
 312                  * and pathspec.
 313                  */
 314                 if (!revs->prune_data)
 315                         return REV_TREE_SAME;
 316         }
 317
 318         tree_difference = REV_TREE_SAME;
 319         DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
 320         if (diff_tree_sha1(t1->object.sha1, t2->object.sha1, "",
 321                            &revs->pruning) < 0)
 322                 return REV_TREE_DIFFERENT;
 323         return tree_difference;
 324 }
 325
 326 static int rev_same_tree_as_empty(struct rev_info *revs, struct commit *commit)
 327 {
 328         int retval;
 329         void *tree;
 330         unsigned long size;
 331         struct tree_desc empty, real;
 332         struct tree *t1 = commit->tree;
 333
 334         if (!t1)
 335                 return 0;
 336
 337         tree = read_object_with_reference(t1->object.sha1, tree_type, &size, NULL);
 338         if (!tree)
 339                 return 0;
 340         init_tree_desc(&real, tree, size);
 341         init_tree_desc(&empty, "", 0);
 342
 343         tree_difference = REV_TREE_SAME;
 344         DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
 345         retval = diff_tree(&empty, &real, "", &revs->pruning);
 346         free(tree);
 347
 348         return retval >= 0 && (tree_difference == REV_TREE_SAME);
 349 }
 350
 351 static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
 352 {
 353         struct commit_list **pp, *parent;
 354         int tree_changed = 0, tree_same = 0;
 355
 356         /*
 357          * If we don't do pruning, everything is interesting
 358          */
 359         if (!revs->prune)
 360                 return;
 361
 362         if (!commit->tree)
 363                 return;
 364
 365         if (!commit->parents) {
 366                 if (rev_same_tree_as_empty(revs, commit))
 367                         commit->object.flags |= TREESAME;
 368                 return;
 369         }
 370
 371         /*
 372          * Normal non-merge commit? If we don't want to make the
 373          * history dense, we consider it always to be a change..
 374          */
 375         if (!revs->dense && !commit->parents->next)
 376                 return;
 377
 378         pp = &commit->parents;
 379         while ((parent = *pp) != NULL) {
 380                 struct commit *p = parent->item;
 381
 382                 if (parse_commit(p) < 0)
 383                         die("cannot simplify commit %s (because of %s)",
 384                             sha1_to_hex(commit->object.sha1),
 385                             sha1_to_hex(p->object.sha1));
 386                 switch (rev_compare_tree(revs, p, commit)) {
 387                 case REV_TREE_SAME:
 388                         tree_same = 1;
 389                         if (!revs->simplify_history || (p->object.flags & UNINTERESTING)) {
 390                                 /* Even if a merge with an uninteresting
 391                                  * side branch brought the entire change
 392                                  * we are interested in, we do not want
 393                                  * to lose the other branches of this
 394                                  * merge, so we just keep going.
 395                                  */
 396                                 pp = &parent->next;
 397                                 continue;
 398                         }
 399                         parent->next = NULL;
 400                         commit->parents = parent;
 401                         commit->object.flags |= TREESAME;
 402                         return;
 403
 404                 case REV_TREE_NEW:
 405                         if (revs->remove_empty_trees &&
 406                             rev_same_tree_as_empty(revs, p)) {
 407                                 /* We are adding all the specified
 408                                  * paths from this parent, so the
 409                                  * history beyond this parent is not
 410                                  * interesting.  Remove its parents
 411                                  * (they are grandparents for us).
 412                                  * IOW, we pretend this parent is a
 413                                  * "root" commit.
 414                                  */
 415                                 if (parse_commit(p) < 0)
 416                                         die("cannot simplify commit %s (invalid %s)",
 417                                             sha1_to_hex(commit->object.sha1),
 418                                             sha1_to_hex(p->object.sha1));
 419                                 p->parents = NULL;
 420                         }
 421                 /* fallthrough */
 422                 case REV_TREE_OLD:
 423                 case REV_TREE_DIFFERENT:
 424                         tree_changed = 1;
 425                         pp = &parent->next;
 426                         continue;
 427                 }
 428                 die("bad tree compare for commit %s", sha1_to_hex(commit->object.sha1));
 429         }
 430         if (tree_changed && !tree_same)
 431                 return;
 432         commit->object.flags |= TREESAME;
 433 }
 434
 435 static void insert_by_date_cached(struct commit *p, struct commit_list **head,
 436                     struct commit_list *cached_base, struct commit_list **cache)
 437 {
 438         struct commit_list *new_entry;
 439
 440         if (cached_base && p->date < cached_base->item->date)
 441                 new_entry = insert_by_date(p, &cached_base->next);
 442         else
 443                 new_entry = insert_by_date(p, head);
 444
 445         if (cache && (!*cache || p->date < (*cache)->item->date))
 446                 *cache = new_entry;
 447 }
 448
 449 static int add_parents_to_list(struct rev_info *revs, struct commit *commit,
 450                     struct commit_list **list, struct commit_list **cache_ptr)
 451 {
 452         struct commit_list *parent = commit->parents;
 453         unsigned left_flag;
 454         struct commit_list *cached_base = cache_ptr ? *cache_ptr : NULL;
 455
 456         if (commit->object.flags & ADDED)
 457                 return 0;
 458         commit->object.flags |= ADDED;
 459
 460         /*
 461          * If the commit is uninteresting, don't try to
 462          * prune parents - we want the maximal uninteresting
 463          * set.
 464          *
 465          * Normally we haven't parsed the parent
 466          * yet, so we won't have a parent of a parent
 467          * here. However, it may turn out that we've
 468          * reached this commit some other way (where it
 469          * wasn't uninteresting), in which case we need
 470          * to mark its parents recursively too..
 471          */
 472         if (commit->object.flags & UNINTERESTING) {
 473                 while (parent) {
 474                         struct commit *p = parent->item;
 475                         parent = parent->next;
 476                         if (p)
 477                                 p->object.flags |= UNINTERESTING;
 478                         if (parse_commit(p) < 0)
 479                                 continue;
 480                         if (p->parents)
 481                                 mark_parents_uninteresting(p);
 482                         if (p->object.flags & SEEN)
 483                                 continue;
 484                         p->object.flags |= SEEN;
 485                         insert_by_date_cached(p, list, cached_base, cache_ptr);
 486                 }
 487                 return 0;
 488         }
 489
 490         /*
 491          * Ok, the commit wasn't uninteresting. Try to
 492          * simplify the commit history and find the parent
 493          * that has no differences in the path set if one exists.
 494          */
 495         try_to_simplify_commit(revs, commit);
 496
 497         if (revs->no_walk)
 498                 return 0;
 499
 500         left_flag = (commit->object.flags & SYMMETRIC_LEFT);
 501
 502         for (parent = commit->parents; parent; parent = parent->next) {
 503                 struct commit *p = parent->item;
 504
 505                 if (parse_commit(p) < 0)
 506                         return -1;
 507                 if (revs->show_source && !p->util)
 508                         p->util = commit->util;
 509                 p->object.flags |= left_flag;
 510                 if (!(p->object.flags & SEEN)) {
 511                         p->object.flags |= SEEN;
 512                         insert_by_date_cached(p, list, cached_base, cache_ptr);
 513                 }
 514                 if (revs->first_parent_only)
 515                         break;
 516         }
 517         return 0;
 518 }
 519
 520 static void cherry_pick_list(struct commit_list *list, struct rev_info *revs)
 521 {
 522         struct commit_list *p;
 523         int left_count = 0, right_count = 0;
 524         int left_first;
 525         struct patch_ids ids;
 526
 527         /* First count the commits on the left and on the right */
 528         for (p = list; p; p = p->next) {
 529                 struct commit *commit = p->item;
 530                 unsigned flags = commit->object.flags;
 531                 if (flags & BOUNDARY)
 532                         ;
 533                 else if (flags & SYMMETRIC_LEFT)
 534                         left_count++;
 535                 else
 536                         right_count++;
 537         }
 538
 539         left_first = left_count < right_count;
 540         init_patch_ids(&ids);
 541         if (revs->diffopt.nr_paths) {
 542                 ids.diffopts.nr_paths = revs->diffopt.nr_paths;
 543                 ids.diffopts.paths = revs->diffopt.paths;
 544                 ids.diffopts.pathlens = revs->diffopt.pathlens;
 545         }
 546
 547         /* Compute patch-ids for one side */
 548         for (p = list; p; p = p->next) {
 549                 struct commit *commit = p->item;
 550                 unsigned flags = commit->object.flags;
 551
 552                 if (flags & BOUNDARY)
 553                         continue;
 554                 /*
 555                  * If we have fewer left, left_first is set and we omit
 556                  * commits on the right branch in this loop.  If we have
 557                  * fewer right, we skip the left ones.
 558                  */
 559                 if (left_first != !!(flags & SYMMETRIC_LEFT))
 560                         continue;
 561                 commit->util = add_commit_patch_id(commit, &ids);
 562         }
 563
 564         /* Check the other side */
 565         for (p = list; p; p = p->next) {
 566                 struct commit *commit = p->item;
 567                 struct patch_id *id;
 568                 unsigned flags = commit->object.flags;
 569
 570                 if (flags & BOUNDARY)
 571                         continue;
 572                 /*
 573                  * If we have fewer left, left_first is set and we omit
 574                  * commits on the left branch in this loop.
 575                  */
 576                 if (left_first == !!(flags & SYMMETRIC_LEFT))
 577                         continue;
 578
 579                 /*
 580                  * Have we seen the same patch id?
 581                  */
 582                 id = has_commit_patch_id(commit, &ids);
 583                 if (!id)
 584                         continue;
 585                 id->seen = 1;
 586                 commit->object.flags |= SHOWN;
 587         }
 588
 589         /* Now check the original side for seen ones */
 590         for (p = list; p; p = p->next) {
 591                 struct commit *commit = p->item;
 592                 struct patch_id *ent;
 593
 594                 ent = commit->util;
 595                 if (!ent)
 596                         continue;
 597                 if (ent->seen)
 598                         commit->object.flags |= SHOWN;
 599                 commit->util = NULL;
 600         }
 601
 602         free_patch_ids(&ids);
 603 }
 604
 605 /* How many extra uninteresting commits we want to see.. */
 606 #define SLOP 5
 607
 608 static int still_interesting(struct commit_list *src, unsigned long date, int slop)
 609 {
 610         /*
 611          * No source list at all? We're definitely done..
 612          */
 613         if (!src)
 614                 return 0;
 615
 616         /*
 617          * Does the destination list contain entries with a date
 618          * before the source list? Definitely _not_ done.
 619          */
 620         if (date < src->item->date)
 621                 return SLOP;
 622
 623         /*
 624          * Does the source list still have interesting commits in
 625          * it? Definitely not done..
 626          */
 627         if (!everybody_uninteresting(src))
 628                 return SLOP;
 629
 630         /* Ok, we're closing in.. */
 631         return slop-1;
 632 }
 633
 634 static int limit_list(struct rev_info *revs)
 635 {
 636         int slop = SLOP;
 637         unsigned long date = ~0ul;
 638         struct commit_list *list = revs->commits;
 639         struct commit_list *newlist = NULL;
 640         struct commit_list **p = &newlist;
 641
 642         while (list) {
 643                 struct commit_list *entry = list;
 644                 struct commit *commit = list->item;
 645                 struct object *obj = &commit->object;
 646                 show_early_output_fn_t show;
 647
 648                 list = list->next;
 649                 free(entry);
 650
 651                 if (revs->max_age != -1 && (commit->date < revs->max_age))
 652                         obj->flags |= UNINTERESTING;
 653                 if (add_parents_to_list(revs, commit, &list, NULL) < 0)
 654                         return -1;
 655                 if (obj->flags & UNINTERESTING) {
 656                         mark_parents_uninteresting(commit);
 657                         if (revs->show_all)
 658                                 p = &commit_list_insert(commit, p)->next;
 659                         slop = still_interesting(list, date, slop);
 660                         if (slop)
 661                                 continue;
 662                         /* If showing all, add the whole pending list to the end */
 663                         if (revs->show_all)
 664                                 *p = list;
 665                         break;
 666                 }
 667                 if (revs->min_age != -1 && (commit->date > revs->min_age))
 668                         continue;
 669                 date = commit->date;
 670                 p = &commit_list_insert(commit, p)->next;
 671
 672                 show = show_early_output;
 673                 if (!show)
 674                         continue;
 675
 676                 show(revs, newlist);
 677                 show_early_output = NULL;
 678         }
 679         if (revs->cherry_pick)
 680                 cherry_pick_list(newlist, revs);
 681
 682         revs->commits = newlist;
 683         return 0;
 684 }
 685
 686 struct all_refs_cb {
 687         int all_flags;
 688         int warned_bad_reflog;
 689         struct rev_info *all_revs;
 690         const char *name_for_errormsg;
 691 };
 692
 693 static int handle_one_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
 694 {
 695         struct all_refs_cb *cb = cb_data;
 696         struct object *object = get_reference(cb->all_revs, path, sha1,
 697                                               cb->all_flags);
 698         add_pending_object(cb->all_revs, object, path);
 699         return 0;
 700 }
 701
 702 static void init_all_refs_cb(struct all_refs_cb *cb, struct rev_info *revs,
 703         unsigned flags)
 704 {
 705         cb->all_revs = revs;
 706         cb->all_flags = flags;
 707 }
 708
 709 static void handle_refs(struct rev_info *revs, unsigned flags,
 710                 int (*for_each)(each_ref_fn, void *))
 711 {
 712         struct all_refs_cb cb;
 713         init_all_refs_cb(&cb, revs, flags);
 714         for_each(handle_one_ref, &cb);
 715 }
 716
 717 static void handle_one_reflog_commit(unsigned char *sha1, void *cb_data)
 718 {
 719         struct all_refs_cb *cb = cb_data;
 720         if (!is_null_sha1(sha1)) {
 721                 struct object *o = parse_object(sha1);
 722                 if (o) {
 723                         o->flags |= cb->all_flags;
 724                         add_pending_object(cb->all_revs, o, "");
 725                 }
 726                 else if (!cb->warned_bad_reflog) {
 727                         warning("reflog of '%s' references pruned commits",
 728                                 cb->name_for_errormsg);
 729                         cb->warned_bad_reflog = 1;
 730                 }
 731         }
 732 }
 733
 734 static int handle_one_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
 735                 const char *email, unsigned long timestamp, int tz,
 736                 const char *message, void *cb_data)
 737 {
 738         handle_one_reflog_commit(osha1, cb_data);
 739         handle_one_reflog_commit(nsha1, cb_data);
 740         return 0;
 741 }
 742
 743 static int handle_one_reflog(const char *path, const unsigned char *sha1, int flag, void *cb_data)
 744 {
 745         struct all_refs_cb *cb = cb_data;
 746         cb->warned_bad_reflog = 0;
 747         cb->name_for_errormsg = path;
 748         for_each_reflog_ent(path, handle_one_reflog_ent, cb_data);
 749         return 0;
 750 }
 751
 752 static void handle_reflog(struct rev_info *revs, unsigned flags)
 753 {
 754         struct all_refs_cb cb;
 755         cb.all_revs = revs;
 756         cb.all_flags = flags;
 757         for_each_reflog(handle_one_reflog, &cb);
 758 }
 759
 760 static int add_parents_only(struct rev_info *revs, const char *arg, int flags)
 761 {
 762         unsigned char sha1[20];
 763         struct object *it;
 764         struct commit *commit;
 765         struct commit_list *parents;
 766
 767         if (*arg == '^') {
 768                 flags ^= UNINTERESTING;
 769                 arg++;
 770         }
 771         if (get_sha1(arg, sha1))
 772                 return 0;
 773         while (1) {
 774                 it = get_reference(revs, arg, sha1, 0);
 775                 if (it->type != OBJ_TAG)
 776                         break;
 777                 if (!((struct tag*)it)->tagged)
 778                         return 0;
 779                 hashcpy(sha1, ((struct tag*)it)->tagged->sha1);
 780         }
 781         if (it->type != OBJ_COMMIT)
 782                 return 0;
 783         commit = (struct commit *)it;
 784         for (parents = commit->parents; parents; parents = parents->next) {
 785                 it = &parents->item->object;
 786                 it->flags |= flags;
 787                 add_pending_object(revs, it, arg);
 788         }
 789         return 1;
 790 }
 791
 792 void init_revisions(struct rev_info *revs, const char *prefix)
 793 {
 794         memset(revs, 0, sizeof(*revs));
 795
 796         revs->abbrev = DEFAULT_ABBREV;
 797         revs->ignore_merges = 1;
 798         revs->simplify_history = 1;
 799         DIFF_OPT_SET(&revs->pruning, RECURSIVE);
 800         DIFF_OPT_SET(&revs->pruning, QUICK);
 801         revs->pruning.add_remove = file_add_remove;
 802         revs->pruning.change = file_change;
 803         revs->lifo = 1;
 804         revs->dense = 1;
 805         revs->prefix = prefix;
 806         revs->max_age = -1;
 807         revs->min_age = -1;
 808         revs->skip_count = -1;
 809         revs->max_count = -1;
 810
 811         revs->commit_format = CMIT_FMT_DEFAULT;
 812
 813         revs->grep_filter.status_only = 1;
 814         revs->grep_filter.pattern_tail = &(revs->grep_filter.pattern_list);
 815         revs->grep_filter.regflags = REG_NEWLINE;
 816
 817         diff_setup(&revs->diffopt);
 818         if (prefix && !revs->diffopt.prefix) {
 819                 revs->diffopt.prefix = prefix;
 820                 revs->diffopt.prefix_length = strlen(prefix);
 821         }
 822 }
 823
 824 static void add_pending_commit_list(struct rev_info *revs,
 825                                     struct commit_list *commit_list,
 826                                     unsigned int flags)
 827 {
 828         while (commit_list) {
 829                 struct object *object = &commit_list->item->object;
 830                 object->flags |= flags;
 831                 add_pending_object(revs, object, sha1_to_hex(object->sha1));
 832                 commit_list = commit_list->next;
 833         }
 834 }
 835
 836 static void prepare_show_merge(struct rev_info *revs)
 837 {
 838         struct commit_list *bases;
 839         struct commit *head, *other;
 840         unsigned char sha1[20];
 841         const char **prune = NULL;
 842         int i, prune_num = 1; /* counting terminating NULL */
 843
 844         if (get_sha1("HEAD", sha1) || !(head = lookup_commit(sha1)))
 845                 die("--merge without HEAD?");
 846         if (get_sha1("MERGE_HEAD", sha1) || !(other = lookup_commit(sha1)))
 847                 die("--merge without MERGE_HEAD?");
 848         add_pending_object(revs, &head->object, "HEAD");
 849         add_pending_object(revs, &other->object, "MERGE_HEAD");
 850         bases = get_merge_bases(head, other, 1);
 851         add_pending_commit_list(revs, bases, UNINTERESTING);
 852         free_commit_list(bases);
 853         head->object.flags |= SYMMETRIC_LEFT;
 854
 855         if (!active_nr)
 856                 read_cache();
 857         for (i = 0; i < active_nr; i++) {
 858                 struct cache_entry *ce = active_cache[i];
 859                 if (!ce_stage(ce))
 860                         continue;
 861                 if (ce_path_match(ce, revs->prune_data)) {
 862                         prune_num++;
 863                         prune = xrealloc(prune, sizeof(*prune) * prune_num);
 864                         prune[prune_num-2] = ce->name;
 865                         prune[prune_num-1] = NULL;
 866                 }
 867                 while ((i+1 < active_nr) &&
 868                        ce_same_name(ce, active_cache[i+1]))
 869                         i++;
 870         }
 871         revs->prune_data = prune;
 872         revs->limited = 1;
 873 }
 874
 875 int handle_revision_arg(const char *arg, struct rev_info *revs,
 876                         int flags,
 877                         int cant_be_filename)
 878 {
 879         unsigned mode;
 880         char *dotdot;
 881         struct object *object;
 882         unsigned char sha1[20];
 883         int local_flags;
 884
 885         dotdot = strstr(arg, "..");
 886         if (dotdot) {
 887                 unsigned char from_sha1[20];
 888                 const char *next = dotdot + 2;
 889                 const char *this = arg;
 890                 int symmetric = *next == '.';
 891                 unsigned int flags_exclude = flags ^ UNINTERESTING;
 892
 893                 *dotdot = 0;
 894                 next += symmetric;
 895
 896                 if (!*next)
 897                         next = "HEAD";
 898                 if (dotdot == arg)
 899                         this = "HEAD";
 900                 if (!get_sha1(this, from_sha1) &&
 901                     !get_sha1(next, sha1)) {
 902                         struct commit *a, *b;
 903                         struct commit_list *exclude;
 904
 905                         a = lookup_commit_reference(from_sha1);
 906                         b = lookup_commit_reference(sha1);
 907                         if (!a || !b) {
 908                                 die(symmetric ?
 909                                     "Invalid symmetric difference expression %s...%s" :
 910                                     "Invalid revision range %s..%s",
 911                                     arg, next);
 912                         }
 913
 914                         if (!cant_be_filename) {
 915                                 *dotdot = '.';
 916                                 verify_non_filename(revs->prefix, arg);
 917                         }
 918
 919                         if (symmetric) {
 920                                 exclude = get_merge_bases(a, b, 1);
 921                                 add_pending_commit_list(revs, exclude,
 922                                                         flags_exclude);
 923                                 free_commit_list(exclude);
 924                                 a->object.flags |= flags | SYMMETRIC_LEFT;
 925                         } else
 926                                 a->object.flags |= flags_exclude;
 927                         b->object.flags |= flags;
 928                         add_pending_object(revs, &a->object, this);
 929                         add_pending_object(revs, &b->object, next);
 930                         return 0;
 931                 }
 932                 *dotdot = '.';
 933         }
 934         dotdot = strstr(arg, "^@");
 935         if (dotdot && !dotdot[2]) {
 936                 *dotdot = 0;
 937                 if (add_parents_only(revs, arg, flags))
 938                         return 0;
 939                 *dotdot = '^';
 940         }
 941         dotdot = strstr(arg, "^!");
 942         if (dotdot && !dotdot[2]) {
 943                 *dotdot = 0;
 944                 if (!add_parents_only(revs, arg, flags ^ UNINTERESTING))
 945                         *dotdot = '^';
 946         }
 947
 948         local_flags = 0;
 949         if (*arg == '^') {
 950                 local_flags = UNINTERESTING;
 951                 arg++;
 952         }
 953         if (get_sha1_with_mode(arg, sha1, &mode))
 954                 return -1;
 955         if (!cant_be_filename)
 956                 verify_non_filename(revs->prefix, arg);
 957         object = get_reference(revs, arg, sha1, flags ^ local_flags);
 958         add_pending_object_with_mode(revs, object, arg, mode);
 959         return 0;
 960 }
 961
 962 static void read_pathspec_from_stdin(struct rev_info *revs, struct strbuf *sb, const char ***prune_data)
 963 {
 964         const char **prune = *prune_data;
 965         int prune_nr;
 966         int prune_alloc;
 967
 968         /* count existing ones */
 969         if (!prune)
 970                 prune_nr = 0;
 971         else
 972                 for (prune_nr = 0; prune[prune_nr]; prune_nr++)
 973                         ;
 974         prune_alloc = prune_nr; /* not really, but we do not know */
 975
 976         while (strbuf_getwholeline(sb, stdin, '\n') != EOF) {
 977                 int len = sb->len;
 978                 if (len && sb->buf[len - 1] == '\n')
 979                         sb->buf[--len] = '\0';
 980                 ALLOC_GROW(prune, prune_nr+1, prune_alloc);
 981                 prune[prune_nr++] = xstrdup(sb->buf);
 982         }
 983         if (prune) {
 984                 ALLOC_GROW(prune, prune_nr+1, prune_alloc);
 985                 prune[prune_nr] = NULL;
 986         }
 987         *prune_data = prune;
 988 }
 989
 990 static void read_revisions_from_stdin(struct rev_info *revs, const char ***prune)
 991 {
 992         struct strbuf sb;
 993         int seen_dashdash = 0;
 994
 995         strbuf_init(&sb, 1000);
 996         while (strbuf_getwholeline(&sb, stdin, '\n') != EOF) {
 997                 int len = sb.len;
 998                 if (len && sb.buf[len - 1] == '\n')
 999                         sb.buf[--len] = '\0';
1000                 if (!len)
1001                         break;
1002                 if (sb.buf[0] == '-') {
1003                         if (len == 2 && sb.buf[1] == '-') {
1004                                 seen_dashdash = 1;
1005                                 break;
1006                         }
1007                         die("options not supported in --stdin mode");
1008                 }
1009                 if (handle_revision_arg(sb.buf, revs, 0, 1))
1010                         die("bad revision '%s'", sb.buf);
1011         }
1012         if (seen_dashdash)
1013                 read_pathspec_from_stdin(revs, &sb, prune);
1014         strbuf_release(&sb);
1015 }
1016
1017 static void add_grep(struct rev_info *revs, const char *ptn, enum grep_pat_token what)
1018 {
1019         append_grep_pattern(&revs->grep_filter, ptn, "command line", 0, what);
1020 }
1021
1022 static void add_header_grep(struct rev_info *revs, enum grep_header_field field, const char *pattern)
1023 {
1024         append_header_grep_pattern(&revs->grep_filter, field, pattern);
1025 }
1026
1027 static void add_message_grep(struct rev_info *revs, const char *pattern)
1028 {
1029         add_grep(revs, pattern, GREP_PATTERN_BODY);
1030 }
1031
1032 static int handle_revision_opt(struct rev_info *revs, int argc, const char **argv,
1033                                int *unkc, const char **unkv)
1034 {
1035         const char *arg = argv[0];
1036
1037         /* pseudo revision arguments */
1038         if (!strcmp(arg, "--all") || !strcmp(arg, "--branches") ||
1039             !strcmp(arg, "--tags") || !strcmp(arg, "--remotes") ||
1040             !strcmp(arg, "--reflog") || !strcmp(arg, "--not") ||
1041             !strcmp(arg, "--no-walk") || !strcmp(arg, "--do-walk") ||
1042             !strcmp(arg, "--bisect"))
1043         {
1044                 unkv[(*unkc)++] = arg;
1045                 return 1;
1046         }
1047
1048         if (!prefixcmp(arg, "--max-count=")) {
1049                 revs->max_count = atoi(arg + 12);
1050         } else if (!prefixcmp(arg, "--skip=")) {
1051                 revs->skip_count = atoi(arg + 7);
1052         } else if ((*arg == '-') && isdigit(arg[1])) {
1053         /* accept -<digit>, like traditional "head" */
1054                 revs->max_count = atoi(arg + 1);
1055         } else if (!strcmp(arg, "-n")) {
1056                 if (argc <= 1)
1057                         return error("-n requires an argument");
1058                 revs->max_count = atoi(argv[1]);
1059                 return 2;
1060         } else if (!prefixcmp(arg, "-n")) {
1061                 revs->max_count = atoi(arg + 2);
1062         } else if (!prefixcmp(arg, "--max-age=")) {
1063                 revs->max_age = atoi(arg + 10);
1064         } else if (!prefixcmp(arg, "--since=")) {
1065                 revs->max_age = approxidate(arg + 8);
1066         } else if (!prefixcmp(arg, "--after=")) {
1067                 revs->max_age = approxidate(arg + 8);
1068         } else if (!prefixcmp(arg, "--min-age=")) {
1069                 revs->min_age = atoi(arg + 10);
1070         } else if (!prefixcmp(arg, "--before=")) {
1071                 revs->min_age = approxidate(arg + 9);
1072         } else if (!prefixcmp(arg, "--until=")) {
1073                 revs->min_age = approxidate(arg + 8);
1074         } else if (!strcmp(arg, "--first-parent")) {
1075                 revs->first_parent_only = 1;
1076         } else if (!strcmp(arg, "-g") || !strcmp(arg, "--walk-reflogs")) {
1077                 init_reflog_walk(&revs->reflog_info);
1078         } else if (!strcmp(arg, "--default")) {
1079                 if (argc <= 1)
1080                         return error("bad --default argument");
1081                 revs->def = argv[1];
1082                 return 2;
1083         } else if (!strcmp(arg, "--merge")) {
1084                 revs->show_merge = 1;
1085         } else if (!strcmp(arg, "--topo-order")) {
1086                 revs->lifo = 1;
1087                 revs->topo_order = 1;
1088         } else if (!strcmp(arg, "--simplify-merges")) {
1089                 revs->simplify_merges = 1;
1090                 revs->rewrite_parents = 1;
1091                 revs->simplify_history = 0;
1092                 revs->limited = 1;
1093         } else if (!strcmp(arg, "--simplify-by-decoration")) {
1094                 revs->simplify_merges = 1;
1095                 revs->rewrite_parents = 1;
1096                 revs->simplify_history = 0;
1097                 revs->simplify_by_decoration = 1;
1098                 revs->limited = 1;
1099                 revs->prune = 1;
1100                 load_ref_decorations(DECORATE_SHORT_REFS);
1101         } else if (!strcmp(arg, "--date-order")) {
1102                 revs->lifo = 0;
1103                 revs->topo_order = 1;
1104         } else if (!prefixcmp(arg, "--early-output")) {
1105                 int count = 100;
1106                 switch (arg[14]) {
1107                 case '=':
1108                         count = atoi(arg+15);
1109                         /* Fallthrough */
1110                 case 0:
1111                         revs->topo_order = 1;
1112                        revs->early_output = count;
1113                 }
1114         } else if (!strcmp(arg, "--parents")) {
1115                 revs->rewrite_parents = 1;
1116                 revs->print_parents = 1;
1117         } else if (!strcmp(arg, "--dense")) {
1118                 revs->dense = 1;
1119         } else if (!strcmp(arg, "--sparse")) {
1120                 revs->dense = 0;
1121         } else if (!strcmp(arg, "--show-all")) {
1122                 revs->show_all = 1;
1123         } else if (!strcmp(arg, "--remove-empty")) {
1124                 revs->remove_empty_trees = 1;
1125         } else if (!strcmp(arg, "--merges")) {
1126                 revs->merges_only = 1;
1127         } else if (!strcmp(arg, "--no-merges")) {
1128                 revs->no_merges = 1;
1129         } else if (!strcmp(arg, "--boundary")) {
1130                 revs->boundary = 1;
1131         } else if (!strcmp(arg, "--left-right")) {
1132                 revs->left_right = 1;
1133         } else if (!strcmp(arg, "--cherry-pick")) {
1134                 revs->cherry_pick = 1;
1135                 revs->limited = 1;
1136         } else if (!strcmp(arg, "--objects")) {
1137                 revs->tag_objects = 1;
1138                 revs->tree_objects = 1;
1139                 revs->blob_objects = 1;
1140         } else if (!strcmp(arg, "--objects-edge")) {
1141                 revs->tag_objects = 1;
1142                 revs->tree_objects = 1;
1143                 revs->blob_objects = 1;
1144                 revs->edge_hint = 1;
1145         } else if (!strcmp(arg, "--unpacked")) {
1146                 revs->unpacked = 1;
1147         } else if (!prefixcmp(arg, "--unpacked=")) {
1148                 die("--unpacked=<packfile> no longer supported.");
1149         } else if (!strcmp(arg, "-r")) {
1150                 revs->diff = 1;
1151                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1152         } else if (!strcmp(arg, "-t")) {
1153                 revs->diff = 1;
1154                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1155                 DIFF_OPT_SET(&revs->diffopt, TREE_IN_RECURSIVE);
1156         } else if (!strcmp(arg, "-m")) {
1157                 revs->ignore_merges = 0;
1158         } else if (!strcmp(arg, "-c")) {
1159                 revs->diff = 1;
1160                 revs->dense_combined_merges = 0;
1161                 revs->combine_merges = 1;
1162         } else if (!strcmp(arg, "--cc")) {
1163                 revs->diff = 1;
1164                 revs->dense_combined_merges = 1;
1165                 revs->combine_merges = 1;
1166         } else if (!strcmp(arg, "-v")) {
1167                 revs->verbose_header = 1;
1168         } else if (!strcmp(arg, "--pretty")) {
1169                 revs->verbose_header = 1;
1170                 get_commit_format(arg+8, revs);
1171         } else if (!prefixcmp(arg, "--pretty=") || !prefixcmp(arg, "--format=")) {
1172                 revs->verbose_header = 1;
1173                 get_commit_format(arg+9, revs);
1174         } else if (!strcmp(arg, "--oneline")) {
1175                 revs->verbose_header = 1;
1176                 get_commit_format("oneline", revs);
1177                 revs->abbrev_commit = 1;
1178         } else if (!strcmp(arg, "--graph")) {
1179                 revs->topo_order = 1;
1180                 revs->rewrite_parents = 1;
1181                 revs->graph = graph_init(revs);
1182         } else if (!strcmp(arg, "--root")) {
1183                 revs->show_root_diff = 1;
1184         } else if (!strcmp(arg, "--no-commit-id")) {
1185                 revs->no_commit_id = 1;
1186         } else if (!strcmp(arg, "--always")) {
1187                 revs->always_show_header = 1;
1188         } else if (!strcmp(arg, "--no-abbrev")) {
1189                 revs->abbrev = 0;
1190         } else if (!strcmp(arg, "--abbrev")) {
1191                 revs->abbrev = DEFAULT_ABBREV;
1192         } else if (!prefixcmp(arg, "--abbrev=")) {
1193                 revs->abbrev = strtoul(arg + 9, NULL, 10);
1194                 if (revs->abbrev < MINIMUM_ABBREV)
1195                         revs->abbrev = MINIMUM_ABBREV;
1196                 else if (revs->abbrev > 40)
1197                         revs->abbrev = 40;
1198         } else if (!strcmp(arg, "--abbrev-commit")) {
1199                 revs->abbrev_commit = 1;
1200         } else if (!strcmp(arg, "--full-diff")) {
1201                 revs->diff = 1;
1202                 revs->full_diff = 1;
1203         } else if (!strcmp(arg, "--full-history")) {
1204                 revs->simplify_history = 0;
1205         } else if (!strcmp(arg, "--relative-date")) {
1206                 revs->date_mode = DATE_RELATIVE;
1207                 revs->date_mode_explicit = 1;
1208         } else if (!strncmp(arg, "--date=", 7)) {
1209                 revs->date_mode = parse_date_format(arg + 7);
1210                 revs->date_mode_explicit = 1;
1211         } else if (!strcmp(arg, "--log-size")) {
1212                 revs->show_log_size = 1;
1213         }
1214         /*
1215          * Grepping the commit log
1216          */
1217         else if (!prefixcmp(arg, "--author=")) {
1218                 add_header_grep(revs, GREP_HEADER_AUTHOR, arg+9);
1219         } else if (!prefixcmp(arg, "--committer=")) {
1220                 add_header_grep(revs, GREP_HEADER_COMMITTER, arg+12);
1221         } else if (!prefixcmp(arg, "--grep=")) {
1222                 add_message_grep(revs, arg+7);
1223         } else if (!strcmp(arg, "--extended-regexp") || !strcmp(arg, "-E")) {
1224                 revs->grep_filter.regflags |= REG_EXTENDED;
1225         } else if (!strcmp(arg, "--regexp-ignore-case") || !strcmp(arg, "-i")) {
1226                 revs->grep_filter.regflags |= REG_ICASE;
1227         } else if (!strcmp(arg, "--fixed-strings") || !strcmp(arg, "-F")) {
1228                 revs->grep_filter.fixed = 1;
1229         } else if (!strcmp(arg, "--all-match")) {
1230                 revs->grep_filter.all_match = 1;
1231         } else if (!prefixcmp(arg, "--encoding=")) {
1232                 arg += 11;
1233                 if (strcmp(arg, "none"))
1234                         git_log_output_encoding = xstrdup(arg);
1235                 else
1236                         git_log_output_encoding = "";
1237         } else if (!strcmp(arg, "--reverse")) {
1238                 revs->reverse ^= 1;
1239         } else if (!strcmp(arg, "--children")) {
1240                 revs->children.name = "children";
1241                 revs->limited = 1;
1242         } else {
1243                 int opts = diff_opt_parse(&revs->diffopt, argv, argc);
1244                 if (!opts)
1245                         unkv[(*unkc)++] = arg;
1246                 return opts;
1247         }
1248
1249         return 1;
1250 }
1251
1252 void parse_revision_opt(struct rev_info *revs, struct parse_opt_ctx_t *ctx,
1253                         const struct option *options,
1254                         const char * const usagestr[])
1255 {
1256         int n = handle_revision_opt(revs, ctx->argc, ctx->argv,
1257                                     &ctx->cpidx, ctx->out);
1258         if (n <= 0) {
1259                 error("unknown option `%s'", ctx->argv[0]);
1260                 usage_with_options(usagestr, options);
1261         }
1262         ctx->argv += n;
1263         ctx->argc -= n;
1264 }
1265
1266 static int for_each_bad_bisect_ref(each_ref_fn fn, void *cb_data)
1267 {
1268         return for_each_ref_in("refs/bisect/bad", fn, cb_data);
1269 }
1270
1271 static int for_each_good_bisect_ref(each_ref_fn fn, void *cb_data)
1272 {
1273         return for_each_ref_in("refs/bisect/good", fn, cb_data);
1274 }
1275
1276 static void append_prune_data(const char ***prune_data, const char **av)
1277 {
1278         const char **prune = *prune_data;
1279         int prune_nr;
1280         int prune_alloc;
1281
1282         if (!prune) {
1283                 *prune_data = av;
1284                 return;
1285         }
1286
1287         /* count existing ones */
1288         for (prune_nr = 0; prune[prune_nr]; prune_nr++)
1289                 ;
1290         prune_alloc = prune_nr; /* not really, but we do not know */
1291
1292         while (*av) {
1293                 ALLOC_GROW(prune, prune_nr+1, prune_alloc);
1294                 prune[prune_nr++] = *av;
1295                 av++;
1296         }
1297         if (prune) {
1298                 ALLOC_GROW(prune, prune_nr+1, prune_alloc);
1299                 prune[prune_nr] = NULL;
1300         }
1301         *prune_data = prune;
1302 }
1303
1304 /*
1305  * Parse revision information, filling in the "rev_info" structure,
1306  * and removing the used arguments from the argument list.
1307  *
1308  * Returns the number of arguments left that weren't recognized
1309  * (which are also moved to the head of the argument list)
1310  */
1311 int setup_revisions(int argc, const char **argv, struct rev_info *revs, const char *def)
1312 {
1313         int i, flags, left, seen_dashdash, read_from_stdin;
1314         const char **prune_data = NULL;
1315
1316         /* First, search for "--" */
1317         seen_dashdash = 0;
1318         for (i = 1; i < argc; i++) {
1319                 const char *arg = argv[i];
1320                 if (strcmp(arg, "--"))
1321                         continue;
1322                 argv[i] = NULL;
1323                 argc = i;
1324                 if (argv[i + 1])
1325                         prune_data = argv + i + 1;
1326                 seen_dashdash = 1;
1327                 break;
1328         }
1329
1330         /* Second, deal with arguments and options */
1331         flags = 0;
1332         read_from_stdin = 0;
1333         for (left = i = 1; i < argc; i++) {
1334                 const char *arg = argv[i];
1335                 if (*arg == '-') {
1336                         int opts;
1337
1338                         if (!strcmp(arg, "--all")) {
1339                                 handle_refs(revs, flags, for_each_ref);
1340                                 handle_refs(revs, flags, head_ref);
1341                                 continue;
1342                         }
1343                         if (!strcmp(arg, "--branches")) {
1344                                 handle_refs(revs, flags, for_each_branch_ref);
1345                                 continue;
1346                         }
1347                         if (!strcmp(arg, "--bisect")) {
1348                                 handle_refs(revs, flags, for_each_bad_bisect_ref);
1349                                 handle_refs(revs, flags ^ UNINTERESTING, for_each_good_bisect_ref);
1350                                 revs->bisect = 1;
1351                                 continue;
1352                         }
1353                         if (!strcmp(arg, "--tags")) {
1354                                 handle_refs(revs, flags, for_each_tag_ref);
1355                                 continue;
1356                         }
1357                         if (!strcmp(arg, "--remotes")) {
1358                                 handle_refs(revs, flags, for_each_remote_ref);
1359                                 continue;
1360                         }
1361                         if (!prefixcmp(arg, "--glob=")) {
1362                                 struct all_refs_cb cb;
1363                                 init_all_refs_cb(&cb, revs, flags);
1364                                 for_each_glob_ref(handle_one_ref, arg + 7, &cb);
1365                                 continue;
1366                         }
1367                         if (!strcmp(arg, "--reflog")) {
1368                                 handle_reflog(revs, flags);
1369                                 continue;
1370                         }
1371                         if (!strcmp(arg, "--not")) {
1372                                 flags ^= UNINTERESTING;
1373                                 continue;
1374                         }
1375                         if (!strcmp(arg, "--no-walk")) {
1376                                 revs->no_walk = 1;
1377                                 continue;
1378                         }
1379                         if (!strcmp(arg, "--do-walk")) {
1380                                 revs->no_walk = 0;
1381                                 continue;
1382                         }
1383                         if (!strcmp(arg, "--stdin")) {
1384                                 if (revs->disable_stdin) {
1385                                         argv[left++] = arg;
1386                                         continue;
1387                                 }
1388                                 if (read_from_stdin++)
1389                                         die("--stdin given twice?");
1390                                 read_revisions_from_stdin(revs, &prune_data);
1391                                 continue;
1392                         }
1393
1394                         opts = handle_revision_opt(revs, argc - i, argv + i, &left, argv);
1395                         if (opts > 0) {
1396                                 i += opts - 1;
1397                                 continue;
1398                         }
1399                         if (opts < 0)
1400                                 exit(128);
1401                         continue;
1402                 }
1403
1404                 if (handle_revision_arg(arg, revs, flags, seen_dashdash)) {
1405                         int j;
1406                         if (seen_dashdash || *arg == '^')
1407                                 die("bad revision '%s'", arg);
1408
1409                         /* If we didn't have a "--":
1410                          * (1) all filenames must exist;
1411                          * (2) all rev-args must not be interpretable
1412                          *     as a valid filename.
1413                          * but the latter we have checked in the main loop.
1414                          */
1415                         for (j = i; j < argc; j++)
1416                                 verify_filename(revs->prefix, argv[j]);
1417
1418                         append_prune_data(&prune_data, argv + i);
1419                         break;
1420                 }
1421         }
1422
1423         if (prune_data)
1424                 revs->prune_data = get_pathspec(revs->prefix, prune_data);
1425
1426         if (revs->def == NULL)
1427                 revs->def = def;
1428         if (revs->show_merge)
1429                 prepare_show_merge(revs);
1430         if (revs->def && !revs->pending.nr) {
1431                 unsigned char sha1[20];
1432                 struct object *object;
1433                 unsigned mode;
1434                 if (get_sha1_with_mode(revs->def, sha1, &mode))
1435                         die("bad default revision '%s'", revs->def);
1436                 object = get_reference(revs, revs->def, sha1, 0);
1437                 add_pending_object_with_mode(revs, object, revs->def, mode);
1438         }
1439
1440         /* Did the user ask for any diff output? Run the diff! */
1441         if (revs->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT)
1442                 revs->diff = 1;
1443
1444         /* Pickaxe, diff-filter and rename following need diffs */
1445         if (revs->diffopt.pickaxe ||
1446             revs->diffopt.filter ||
1447             DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1448                 revs->diff = 1;
1449
1450         if (revs->topo_order)
1451                 revs->limited = 1;
1452
1453         if (revs->prune_data) {
1454                 diff_tree_setup_paths(revs->prune_data, &revs->pruning);
1455                 /* Can't prune commits with rename following: the paths change.. */
1456                 if (!DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1457                         revs->prune = 1;
1458                 if (!revs->full_diff)
1459                         diff_tree_setup_paths(revs->prune_data, &revs->diffopt);
1460         }
1461         if (revs->combine_merges) {
1462                 revs->ignore_merges = 0;
1463                 if (revs->dense_combined_merges && !revs->diffopt.output_format)
1464                         revs->diffopt.output_format = DIFF_FORMAT_PATCH;
1465         }
1466         revs->diffopt.abbrev = revs->abbrev;
1467         if (diff_setup_done(&revs->diffopt) < 0)
1468                 die("diff_setup_done failed");
1469
1470         compile_grep_patterns(&revs->grep_filter);
1471
1472         if (revs->reverse && revs->reflog_info)
1473                 die("cannot combine --reverse with --walk-reflogs");
1474         if (revs->rewrite_parents && revs->children.name)
1475                 die("cannot combine --parents and --children");
1476
1477         /*
1478          * Limitations on the graph functionality
1479          */
1480         if (revs->reverse && revs->graph)
1481                 die("cannot combine --reverse with --graph");
1482
1483         if (revs->reflog_info && revs->graph)
1484                 die("cannot combine --walk-reflogs with --graph");
1485
1486         return left;
1487 }
1488
1489 static void add_child(struct rev_info *revs, struct commit *parent, struct commit *child)
1490 {
1491         struct commit_list *l = xcalloc(1, sizeof(*l));
1492
1493         l->item = child;
1494         l->next = add_decoration(&revs->children, &parent->object, l);
1495 }
1496
1497 static int remove_duplicate_parents(struct commit *commit)
1498 {
1499         struct commit_list **pp, *p;
1500         int surviving_parents;
1501
1502         /* Examine existing parents while marking ones we have seen... */
1503         pp = &commit->parents;
1504         while ((p = *pp) != NULL) {
1505                 struct commit *parent = p->item;
1506                 if (parent->object.flags & TMP_MARK) {
1507                         *pp = p->next;
1508                         continue;
1509                 }
1510                 parent->object.flags |= TMP_MARK;
1511                 pp = &p->next;
1512         }
1513         /* count them while clearing the temporary mark */
1514         surviving_parents = 0;
1515         for (p = commit->parents; p; p = p->next) {
1516                 p->item->object.flags &= ~TMP_MARK;
1517                 surviving_parents++;
1518         }
1519         return surviving_parents;
1520 }
1521
1522 struct merge_simplify_state {
1523         struct commit *simplified;
1524 };
1525
1526 static struct merge_simplify_state *locate_simplify_state(struct rev_info *revs, struct commit *commit)
1527 {
1528         struct merge_simplify_state *st;
1529
1530         st = lookup_decoration(&revs->merge_simplification, &commit->object);
1531         if (!st) {
1532                 st = xcalloc(1, sizeof(*st));
1533                 add_decoration(&revs->merge_simplification, &commit->object, st);
1534         }
1535         return st;
1536 }
1537
1538 static struct commit_list **simplify_one(struct rev_info *revs, struct commit *commit, struct commit_list **tail)
1539 {
1540         struct commit_list *p;
1541         struct merge_simplify_state *st, *pst;
1542         int cnt;
1543
1544         st = locate_simplify_state(revs, commit);
1545
1546         /*
1547          * Have we handled this one?
1548          */
1549         if (st->simplified)
1550                 return tail;
1551
1552         /*
1553          * An UNINTERESTING commit simplifies to itself, so does a
1554          * root commit.  We do not rewrite parents of such commit
1555          * anyway.
1556          */
1557         if ((commit->object.flags & UNINTERESTING) || !commit->parents) {
1558                 st->simplified = commit;
1559                 return tail;
1560         }
1561
1562         /*
1563          * Do we know what commit all of our parents should be rewritten to?
1564          * Otherwise we are not ready to rewrite this one yet.
1565          */
1566         for (cnt = 0, p = commit->parents; p; p = p->next) {
1567                 pst = locate_simplify_state(revs, p->item);
1568                 if (!pst->simplified) {
1569                         tail = &commit_list_insert(p->item, tail)->next;
1570                         cnt++;
1571                 }
1572         }
1573         if (cnt) {
1574                 tail = &commit_list_insert(commit, tail)->next;
1575                 return tail;
1576         }
1577
1578         /*
1579          * Rewrite our list of parents.
1580          */
1581         for (p = commit->parents; p; p = p->next) {
1582                 pst = locate_simplify_state(revs, p->item);
1583                 p->item = pst->simplified;
1584         }
1585         cnt = remove_duplicate_parents(commit);
1586
1587         /*
1588          * It is possible that we are a merge and one side branch
1589          * does not have any commit that touches the given paths;
1590          * in such a case, the immediate parents will be rewritten
1591          * to different commits.
1592          *
1593          *      o----X          X: the commit we are looking at;
1594          *     /    /           o: a commit that touches the paths;
1595          * ---o----'
1596          *
1597          * Further reduce the parents by removing redundant parents.
1598          */
1599         if (1 < cnt) {
1600                 struct commit_list *h = reduce_heads(commit->parents);
1601                 cnt = commit_list_count(h);
1602                 free_commit_list(commit->parents);
1603                 commit->parents = h;
1604         }
1605
1606         /*
1607          * A commit simplifies to itself if it is a root, if it is
1608          * UNINTERESTING, if it touches the given paths, or if it is a
1609          * merge and its parents simplifies to more than one commits
1610          * (the first two cases are already handled at the beginning of
1611          * this function).
1612          *
1613          * Otherwise, it simplifies to what its sole parent simplifies to.
1614          */
1615         if (!cnt ||
1616             (commit->object.flags & UNINTERESTING) ||
1617             !(commit->object.flags & TREESAME) ||
1618             (1 < cnt))
1619                 st->simplified = commit;
1620         else {
1621                 pst = locate_simplify_state(revs, commit->parents->item);
1622                 st->simplified = pst->simplified;
1623         }
1624         return tail;
1625 }
1626
1627 static void simplify_merges(struct rev_info *revs)
1628 {
1629         struct commit_list *list;
1630         struct commit_list *yet_to_do, **tail;
1631
1632         if (!revs->topo_order)
1633                 sort_in_topological_order(&revs->commits, revs->lifo);
1634         if (!revs->prune)
1635                 return;
1636
1637         /* feed the list reversed */
1638         yet_to_do = NULL;
1639         for (list = revs->commits; list; list = list->next)
1640                 commit_list_insert(list->item, &yet_to_do);
1641         while (yet_to_do) {
1642                 list = yet_to_do;
1643                 yet_to_do = NULL;
1644                 tail = &yet_to_do;
1645                 while (list) {
1646                         struct commit *commit = list->item;
1647                         struct commit_list *next = list->next;
1648                         free(list);
1649                         list = next;
1650                         tail = simplify_one(revs, commit, tail);
1651                 }
1652         }
1653
1654         /* clean up the result, removing the simplified ones */
1655         list = revs->commits;
1656         revs->commits = NULL;
1657         tail = &revs->commits;
1658         while (list) {
1659                 struct commit *commit = list->item;
1660                 struct commit_list *next = list->next;
1661                 struct merge_simplify_state *st;
1662                 free(list);
1663                 list = next;
1664                 st = locate_simplify_state(revs, commit);
1665                 if (st->simplified == commit)
1666                         tail = &commit_list_insert(commit, tail)->next;
1667         }
1668 }
1669
1670 static void set_children(struct rev_info *revs)
1671 {
1672         struct commit_list *l;
1673         for (l = revs->commits; l; l = l->next) {
1674                 struct commit *commit = l->item;
1675                 struct commit_list *p;
1676
1677                 for (p = commit->parents; p; p = p->next)
1678                         add_child(revs, p->item, commit);
1679         }
1680 }
1681
1682 int prepare_revision_walk(struct rev_info *revs)
1683 {
1684         int nr = revs->pending.nr;
1685         struct object_array_entry *e, *list;
1686
1687         e = list = revs->pending.objects;
1688         revs->pending.nr = 0;
1689         revs->pending.alloc = 0;
1690         revs->pending.objects = NULL;
1691         while (--nr >= 0) {
1692                 struct commit *commit = handle_commit(revs, e->item, e->name);
1693                 if (commit) {
1694                         if (!(commit->object.flags & SEEN)) {
1695                                 commit->object.flags |= SEEN;
1696                                 insert_by_date(commit, &revs->commits);
1697                         }
1698                 }
1699                 e++;
1700         }
1701         free(list);
1702
1703         if (revs->no_walk)
1704                 return 0;
1705         if (revs->limited)
1706                 if (limit_list(revs) < 0)
1707                         return -1;
1708         if (revs->topo_order)
1709                 sort_in_topological_order(&revs->commits, revs->lifo);
1710         if (revs->simplify_merges)
1711                 simplify_merges(revs);
1712         if (revs->children.name)
1713                 set_children(revs);
1714         return 0;
1715 }
1716
1717 enum rewrite_result {
1718         rewrite_one_ok,
1719         rewrite_one_noparents,
1720         rewrite_one_error,
1721 };
1722
1723 static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp)
1724 {
1725         struct commit_list *cache = NULL;
1726
1727         for (;;) {
1728                 struct commit *p = *pp;
1729                 if (!revs->limited)
1730                         if (add_parents_to_list(revs, p, &revs->commits, &cache) < 0)
1731                                 return rewrite_one_error;
1732                 if (p->parents && p->parents->next)
1733                         return rewrite_one_ok;
1734                 if (p->object.flags & UNINTERESTING)
1735                         return rewrite_one_ok;
1736                 if (!(p->object.flags & TREESAME))
1737                         return rewrite_one_ok;
1738                 if (!p->parents)
1739                         return rewrite_one_noparents;
1740                 *pp = p->parents->item;
1741         }
1742 }
1743
1744 static int rewrite_parents(struct rev_info *revs, struct commit *commit)
1745 {
1746         struct commit_list **pp = &commit->parents;
1747         while (*pp) {
1748                 struct commit_list *parent = *pp;
1749                 switch (rewrite_one(revs, &parent->item)) {
1750                 case rewrite_one_ok:
1751                         break;
1752                 case rewrite_one_noparents:
1753                         *pp = parent->next;
1754                         continue;
1755                 case rewrite_one_error:
1756                         return -1;
1757                 }
1758                 pp = &parent->next;
1759         }
1760         remove_duplicate_parents(commit);
1761         return 0;
1762 }
1763
1764 static int commit_match(struct commit *commit, struct rev_info *opt)
1765 {
1766         if (!opt->grep_filter.pattern_list)
1767                 return 1;
1768         return grep_buffer(&opt->grep_filter,
1769                            NULL, /* we say nothing, not even filename */
1770                            commit->buffer, strlen(commit->buffer));
1771 }
1772
1773 static inline int want_ancestry(struct rev_info *revs)
1774 {
1775         return (revs->rewrite_parents || revs->children.name);
1776 }
1777
1778 enum commit_action get_commit_action(struct rev_info *revs, struct commit *commit)
1779 {
1780         if (commit->object.flags & SHOWN)
1781                 return commit_ignore;
1782         if (revs->unpacked && has_sha1_pack(commit->object.sha1))
1783                 return commit_ignore;
1784         if (revs->show_all)
1785                 return commit_show;
1786         if (commit->object.flags & UNINTERESTING)
1787                 return commit_ignore;
1788         if (revs->min_age != -1 && (commit->date > revs->min_age))
1789                 return commit_ignore;
1790         if (revs->no_merges && commit->parents && commit->parents->next)
1791                 return commit_ignore;
1792         if (revs->merges_only && !(commit->parents && commit->parents->next))
1793                 return commit_ignore;
1794         if (!commit_match(commit, revs))
1795                 return commit_ignore;
1796         if (revs->prune && revs->dense) {
1797                 /* Commit without changes? */
1798                 if (commit->object.flags & TREESAME) {
1799                         /* drop merges unless we want parenthood */
1800                         if (!want_ancestry(revs))
1801                                 return commit_ignore;
1802                         /* non-merge - always ignore it */
1803                         if (!commit->parents || !commit->parents->next)
1804                                 return commit_ignore;
1805                 }
1806         }
1807         return commit_show;
1808 }
1809
1810 enum commit_action simplify_commit(struct rev_info *revs, struct commit *commit)
1811 {
1812         enum commit_action action = get_commit_action(revs, commit);
1813
1814         if (action == commit_show &&
1815             !revs->show_all &&
1816             revs->prune && revs->dense && want_ancestry(revs)) {
1817                 if (rewrite_parents(revs, commit) < 0)
1818                         return commit_error;
1819         }
1820         return action;
1821 }
1822
1823 static struct commit *get_revision_1(struct rev_info *revs)
1824 {
1825         if (!revs->commits)
1826                 return NULL;
1827
1828         do {
1829                 struct commit_list *entry = revs->commits;
1830                 struct commit *commit = entry->item;
1831
1832                 revs->commits = entry->next;
1833                 free(entry);
1834
1835                 if (revs->reflog_info)
1836                         fake_reflog_parent(revs->reflog_info, commit);
1837
1838                 /*
1839                  * If we haven't done the list limiting, we need to look at
1840                  * the parents here. We also need to do the date-based limiting
1841                  * that we'd otherwise have done in limit_list().
1842                  */
1843                 if (!revs->limited) {
1844                         if (revs->max_age != -1 &&
1845                             (commit->date < revs->max_age))
1846                                 continue;
1847                         if (add_parents_to_list(revs, commit, &revs->commits, NULL) < 0)
1848                                 die("Failed to traverse parents of commit %s",
1849                                     sha1_to_hex(commit->object.sha1));
1850                 }
1851
1852                 switch (simplify_commit(revs, commit)) {
1853                 case commit_ignore:
1854                         continue;
1855                 case commit_error:
1856                         die("Failed to simplify parents of commit %s",
1857                             sha1_to_hex(commit->object.sha1));
1858                 default:
1859                         return commit;
1860                 }
1861         } while (revs->commits);
1862         return NULL;
1863 }
1864
1865 static void gc_boundary(struct object_array *array)
1866 {
1867         unsigned nr = array->nr;
1868         unsigned alloc = array->alloc;
1869         struct object_array_entry *objects = array->objects;
1870
1871         if (alloc <= nr) {
1872                 unsigned i, j;
1873                 for (i = j = 0; i < nr; i++) {
1874                         if (objects[i].item->flags & SHOWN)
1875                                 continue;
1876                         if (i != j)
1877                                 objects[j] = objects[i];
1878                         j++;
1879                 }
1880                 for (i = j; i < nr; i++)
1881                         objects[i].item = NULL;
1882                 array->nr = j;
1883         }
1884 }
1885
1886 static void create_boundary_commit_list(struct rev_info *revs)
1887 {
1888         unsigned i;
1889         struct commit *c;
1890         struct object_array *array = &revs->boundary_commits;
1891         struct object_array_entry *objects = array->objects;
1892
1893         /*
1894          * If revs->commits is non-NULL at this point, an error occurred in
1895          * get_revision_1().  Ignore the error and continue printing the
1896          * boundary commits anyway.  (This is what the code has always
1897          * done.)
1898          */
1899         if (revs->commits) {
1900                 free_commit_list(revs->commits);
1901                 revs->commits = NULL;
1902         }
1903
1904         /*
1905          * Put all of the actual boundary commits from revs->boundary_commits
1906          * into revs->commits
1907          */
1908         for (i = 0; i < array->nr; i++) {
1909                 c = (struct commit *)(objects[i].item);
1910                 if (!c)
1911                         continue;
1912                 if (!(c->object.flags & CHILD_SHOWN))
1913                         continue;
1914                 if (c->object.flags & (SHOWN | BOUNDARY))
1915                         continue;
1916                 c->object.flags |= BOUNDARY;
1917                 commit_list_insert(c, &revs->commits);
1918         }
1919
1920         /*
1921          * If revs->topo_order is set, sort the boundary commits
1922          * in topological order
1923          */
1924         sort_in_topological_order(&revs->commits, revs->lifo);
1925 }
1926
1927 static struct commit *get_revision_internal(struct rev_info *revs)
1928 {
1929         struct commit *c = NULL;
1930         struct commit_list *l;
1931
1932         if (revs->boundary == 2) {
1933                 /*
1934                  * All of the normal commits have already been returned,
1935                  * and we are now returning boundary commits.
1936                  * create_boundary_commit_list() has populated
1937                  * revs->commits with the remaining commits to return.
1938                  */
1939                 c = pop_commit(&revs->commits);
1940                 if (c)
1941                         c->object.flags |= SHOWN;
1942                 return c;
1943         }
1944
1945         /*
1946          * Now pick up what they want to give us
1947          */
1948         c = get_revision_1(revs);
1949         if (c) {
1950                 while (0 < revs->skip_count) {
1951                         revs->skip_count--;
1952                         c = get_revision_1(revs);
1953                         if (!c)
1954                                 break;
1955                 }
1956         }
1957
1958         /*
1959          * Check the max_count.
1960          */
1961         switch (revs->max_count) {
1962         case -1:
1963                 break;
1964         case 0:
1965                 c = NULL;
1966                 break;
1967         default:
1968                 revs->max_count--;
1969         }
1970
1971         if (c)
1972                 c->object.flags |= SHOWN;
1973
1974         if (!revs->boundary) {
1975                 return c;
1976         }
1977
1978         if (!c) {
1979                 /*
1980                  * get_revision_1() runs out the commits, and
1981                  * we are done computing the boundaries.
1982                  * switch to boundary commits output mode.
1983                  */
1984                 revs->boundary = 2;
1985
1986                 /*
1987                  * Update revs->commits to contain the list of
1988                  * boundary commits.
1989                  */
1990                 create_boundary_commit_list(revs);
1991
1992                 return get_revision_internal(revs);
1993         }
1994
1995         /*
1996          * boundary commits are the commits that are parents of the
1997          * ones we got from get_revision_1() but they themselves are
1998          * not returned from get_revision_1().  Before returning
1999          * 'c', we need to mark its parents that they could be boundaries.
2000          */
2001
2002         for (l = c->parents; l; l = l->next) {
2003                 struct object *p;
2004                 p = &(l->item->object);
2005                 if (p->flags & (CHILD_SHOWN | SHOWN))
2006                         continue;
2007                 p->flags |= CHILD_SHOWN;
2008                 gc_boundary(&revs->boundary_commits);
2009                 add_object_array(p, NULL, &revs->boundary_commits);
2010         }
2011
2012         return c;
2013 }
2014
2015 struct commit *get_revision(struct rev_info *revs)
2016 {
2017         struct commit *c;
2018         struct commit_list *reversed;
2019
2020         if (revs->reverse) {
2021                 reversed = NULL;
2022                 while ((c = get_revision_internal(revs))) {
2023                         commit_list_insert(c, &reversed);
2024                 }
2025                 revs->commits = reversed;
2026                 revs->reverse = 0;
2027                 revs->reverse_output_stage = 1;
2028         }
2029
2030         if (revs->reverse_output_stage)
2031                 return pop_commit(&revs->commits);
2032
2033         c = get_revision_internal(revs);
2034         if (c && revs->graph)
2035                 graph_update(revs->graph, c);
2036         return c;
2037 }