git.oblomov.eu Git - git/blob - revision.c

   1 #include "cache.h"
   2 #include "tag.h"
   3 #include "blob.h"
   4 #include "tree.h"
   5 #include "commit.h"
   6 #include "diff.h"
   7 #include "refs.h"
   8 #include "revision.h"
   9 #include "graph.h"
  10 #include "grep.h"
  11 #include "reflog-walk.h"
  12 #include "patch-ids.h"
  13 #include "decorate.h"
  14 #include "log-tree.h"
  15
  16 volatile show_early_output_fn_t show_early_output;
  17
  18 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                 die("object ranges do not make sense when not walking revisions");
 137         if (revs->reflog_info && obj->type == OBJ_COMMIT &&
 138                         add_reflog_for_walk(revs->reflog_info,
 139                                 (struct commit *)obj, name))
 140                 return;
 141         add_object_array_with_mode(obj, name, &revs->pending, mode);
 142 }
 143
 144 void add_pending_object(struct rev_info *revs, struct object *obj, const char *name)
 145 {
 146         add_pending_object_with_mode(revs, obj, name, S_IFINVALID);
 147 }
 148
 149 void add_head_to_pending(struct rev_info *revs)
 150 {
 151         unsigned char sha1[20];
 152         struct object *obj;
 153         if (get_sha1("HEAD", sha1))
 154                 return;
 155         obj = parse_object(sha1);
 156         if (!obj)
 157                 return;
 158         add_pending_object(revs, obj, "HEAD");
 159 }
 160
 161 static struct object *get_reference(struct rev_info *revs, const char *name, const unsigned char *sha1, unsigned int flags)
 162 {
 163         struct object *object;
 164
 165         object = parse_object(sha1);
 166         if (!object)
 167                 die("bad object %s", name);
 168         object->flags |= flags;
 169         return object;
 170 }
 171
 172 static struct commit *handle_commit(struct rev_info *revs, struct object *object, const char *name)
 173 {
 174         unsigned long flags = object->flags;
 175
 176         /*
 177          * Tag object? Look what it points to..
 178          */
 179         while (object->type == OBJ_TAG) {
 180                 struct tag *tag = (struct tag *) object;
 181                 if (revs->tag_objects && !(flags & UNINTERESTING))
 182                         add_pending_object(revs, object, tag->tag);
 183                 if (!tag->tagged)
 184                         die("bad tag");
 185                 object = parse_object(tag->tagged->sha1);
 186                 if (!object) {
 187                         if (flags & UNINTERESTING)
 188                                 return NULL;
 189                         die("bad object %s", sha1_to_hex(tag->tagged->sha1));
 190                 }
 191         }
 192
 193         /*
 194          * Commit object? Just return it, we'll do all the complex
 195          * reachability crud.
 196          */
 197         if (object->type == OBJ_COMMIT) {
 198                 struct commit *commit = (struct commit *)object;
 199                 if (parse_commit(commit) < 0)
 200                         die("unable to parse commit %s", name);
 201                 if (flags & UNINTERESTING) {
 202                         commit->object.flags |= UNINTERESTING;
 203                         mark_parents_uninteresting(commit);
 204                         revs->limited = 1;
 205                 }
 206                 if (revs->show_source && !commit->util)
 207                         commit->util = (void *) name;
 208                 return commit;
 209         }
 210
 211         /*
 212          * Tree object? Either mark it 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 handle_refs(struct rev_info *revs, unsigned flags,
 703                 int (*for_each)(each_ref_fn, void *))
 704 {
 705         struct all_refs_cb cb;
 706         cb.all_revs = revs;
 707         cb.all_flags = flags;
 708         for_each(handle_one_ref, &cb);
 709 }
 710
 711 static void handle_one_reflog_commit(unsigned char *sha1, void *cb_data)
 712 {
 713         struct all_refs_cb *cb = cb_data;
 714         if (!is_null_sha1(sha1)) {
 715                 struct object *o = parse_object(sha1);
 716                 if (o) {
 717                         o->flags |= cb->all_flags;
 718                         add_pending_object(cb->all_revs, o, "");
 719                 }
 720                 else if (!cb->warned_bad_reflog) {
 721                         warning("reflog of '%s' references pruned commits",
 722                                 cb->name_for_errormsg);
 723                         cb->warned_bad_reflog = 1;
 724                 }
 725         }
 726 }
 727
 728 static int handle_one_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
 729                 const char *email, unsigned long timestamp, int tz,
 730                 const char *message, void *cb_data)
 731 {
 732         handle_one_reflog_commit(osha1, cb_data);
 733         handle_one_reflog_commit(nsha1, cb_data);
 734         return 0;
 735 }
 736
 737 static int handle_one_reflog(const char *path, const unsigned char *sha1, int flag, void *cb_data)
 738 {
 739         struct all_refs_cb *cb = cb_data;
 740         cb->warned_bad_reflog = 0;
 741         cb->name_for_errormsg = path;
 742         for_each_reflog_ent(path, handle_one_reflog_ent, cb_data);
 743         return 0;
 744 }
 745
 746 static void handle_reflog(struct rev_info *revs, unsigned flags)
 747 {
 748         struct all_refs_cb cb;
 749         cb.all_revs = revs;
 750         cb.all_flags = flags;
 751         for_each_reflog(handle_one_reflog, &cb);
 752 }
 753
 754 static int add_parents_only(struct rev_info *revs, const char *arg, int flags)
 755 {
 756         unsigned char sha1[20];
 757         struct object *it;
 758         struct commit *commit;
 759         struct commit_list *parents;
 760
 761         if (*arg == '^') {
 762                 flags ^= UNINTERESTING;
 763                 arg++;
 764         }
 765         if (get_sha1(arg, sha1))
 766                 return 0;
 767         while (1) {
 768                 it = get_reference(revs, arg, sha1, 0);
 769                 if (it->type != OBJ_TAG)
 770                         break;
 771                 if (!((struct tag*)it)->tagged)
 772                         return 0;
 773                 hashcpy(sha1, ((struct tag*)it)->tagged->sha1);
 774         }
 775         if (it->type != OBJ_COMMIT)
 776                 return 0;
 777         commit = (struct commit *)it;
 778         for (parents = commit->parents; parents; parents = parents->next) {
 779                 it = &parents->item->object;
 780                 it->flags |= flags;
 781                 add_pending_object(revs, it, arg);
 782         }
 783         return 1;
 784 }
 785
 786 void init_revisions(struct rev_info *revs, const char *prefix)
 787 {
 788         memset(revs, 0, sizeof(*revs));
 789
 790         revs->abbrev = DEFAULT_ABBREV;
 791         revs->ignore_merges = 1;
 792         revs->simplify_history = 1;
 793         DIFF_OPT_SET(&revs->pruning, RECURSIVE);
 794         DIFF_OPT_SET(&revs->pruning, QUIET);
 795         revs->pruning.add_remove = file_add_remove;
 796         revs->pruning.change = file_change;
 797         revs->lifo = 1;
 798         revs->dense = 1;
 799         revs->prefix = prefix;
 800         revs->max_age = -1;
 801         revs->min_age = -1;
 802         revs->skip_count = -1;
 803         revs->max_count = -1;
 804
 805         revs->commit_format = CMIT_FMT_DEFAULT;
 806
 807         revs->grep_filter.status_only = 1;
 808         revs->grep_filter.pattern_tail = &(revs->grep_filter.pattern_list);
 809         revs->grep_filter.regflags = REG_NEWLINE;
 810
 811         diff_setup(&revs->diffopt);
 812         if (prefix && !revs->diffopt.prefix) {
 813                 revs->diffopt.prefix = prefix;
 814                 revs->diffopt.prefix_length = strlen(prefix);
 815         }
 816 }
 817
 818 static void add_pending_commit_list(struct rev_info *revs,
 819                                     struct commit_list *commit_list,
 820                                     unsigned int flags)
 821 {
 822         while (commit_list) {
 823                 struct object *object = &commit_list->item->object;
 824                 object->flags |= flags;
 825                 add_pending_object(revs, object, sha1_to_hex(object->sha1));
 826                 commit_list = commit_list->next;
 827         }
 828 }
 829
 830 static void prepare_show_merge(struct rev_info *revs)
 831 {
 832         struct commit_list *bases;
 833         struct commit *head, *other;
 834         unsigned char sha1[20];
 835         const char **prune = NULL;
 836         int i, prune_num = 1; /* counting terminating NULL */
 837
 838         if (get_sha1("HEAD", sha1) || !(head = lookup_commit(sha1)))
 839                 die("--merge without HEAD?");
 840         if (get_sha1("MERGE_HEAD", sha1) || !(other = lookup_commit(sha1)))
 841                 die("--merge without MERGE_HEAD?");
 842         add_pending_object(revs, &head->object, "HEAD");
 843         add_pending_object(revs, &other->object, "MERGE_HEAD");
 844         bases = get_merge_bases(head, other, 1);
 845         add_pending_commit_list(revs, bases, UNINTERESTING);
 846         free_commit_list(bases);
 847         head->object.flags |= SYMMETRIC_LEFT;
 848
 849         if (!active_nr)
 850                 read_cache();
 851         for (i = 0; i < active_nr; i++) {
 852                 struct cache_entry *ce = active_cache[i];
 853                 if (!ce_stage(ce))
 854                         continue;
 855                 if (ce_path_match(ce, revs->prune_data)) {
 856                         prune_num++;
 857                         prune = xrealloc(prune, sizeof(*prune) * prune_num);
 858                         prune[prune_num-2] = ce->name;
 859                         prune[prune_num-1] = NULL;
 860                 }
 861                 while ((i+1 < active_nr) &&
 862                        ce_same_name(ce, active_cache[i+1]))
 863                         i++;
 864         }
 865         revs->prune_data = prune;
 866         revs->limited = 1;
 867 }
 868
 869 int handle_revision_arg(const char *arg, struct rev_info *revs,
 870                         int flags,
 871                         int cant_be_filename)
 872 {
 873         unsigned mode;
 874         char *dotdot;
 875         struct object *object;
 876         unsigned char sha1[20];
 877         int local_flags;
 878
 879         dotdot = strstr(arg, "..");
 880         if (dotdot) {
 881                 unsigned char from_sha1[20];
 882                 const char *next = dotdot + 2;
 883                 const char *this = arg;
 884                 int symmetric = *next == '.';
 885                 unsigned int flags_exclude = flags ^ UNINTERESTING;
 886
 887                 *dotdot = 0;
 888                 next += symmetric;
 889
 890                 if (!*next)
 891                         next = "HEAD";
 892                 if (dotdot == arg)
 893                         this = "HEAD";
 894                 if (!get_sha1(this, from_sha1) &&
 895                     !get_sha1(next, sha1)) {
 896                         struct commit *a, *b;
 897                         struct commit_list *exclude;
 898
 899                         a = lookup_commit_reference(from_sha1);
 900                         b = lookup_commit_reference(sha1);
 901                         if (!a || !b) {
 902                                 die(symmetric ?
 903                                     "Invalid symmetric difference expression %s...%s" :
 904                                     "Invalid revision range %s..%s",
 905                                     arg, next);
 906                         }
 907
 908                         if (!cant_be_filename) {
 909                                 *dotdot = '.';
 910                                 verify_non_filename(revs->prefix, arg);
 911                         }
 912
 913                         if (symmetric) {
 914                                 exclude = get_merge_bases(a, b, 1);
 915                                 add_pending_commit_list(revs, exclude,
 916                                                         flags_exclude);
 917                                 free_commit_list(exclude);
 918                                 a->object.flags |= flags | SYMMETRIC_LEFT;
 919                         } else
 920                                 a->object.flags |= flags_exclude;
 921                         b->object.flags |= flags;
 922                         add_pending_object(revs, &a->object, this);
 923                         add_pending_object(revs, &b->object, next);
 924                         return 0;
 925                 }
 926                 *dotdot = '.';
 927         }
 928         dotdot = strstr(arg, "^@");
 929         if (dotdot && !dotdot[2]) {
 930                 *dotdot = 0;
 931                 if (add_parents_only(revs, arg, flags))
 932                         return 0;
 933                 *dotdot = '^';
 934         }
 935         dotdot = strstr(arg, "^!");
 936         if (dotdot && !dotdot[2]) {
 937                 *dotdot = 0;
 938                 if (!add_parents_only(revs, arg, flags ^ UNINTERESTING))
 939                         *dotdot = '^';
 940         }
 941
 942         local_flags = 0;
 943         if (*arg == '^') {
 944                 local_flags = UNINTERESTING;
 945                 arg++;
 946         }
 947         if (get_sha1_with_mode(arg, sha1, &mode))
 948                 return -1;
 949         if (!cant_be_filename)
 950                 verify_non_filename(revs->prefix, arg);
 951         object = get_reference(revs, arg, sha1, flags ^ local_flags);
 952         add_pending_object_with_mode(revs, object, arg, mode);
 953         return 0;
 954 }
 955
 956 void read_revisions_from_stdin(struct rev_info *revs)
 957 {
 958         char line[1000];
 959
 960         while (fgets(line, sizeof(line), stdin) != NULL) {
 961                 int len = strlen(line);
 962                 if (len && line[len - 1] == '\n')
 963                         line[--len] = '\0';
 964                 if (!len)
 965                         break;
 966                 if (line[0] == '-')
 967                         die("options not supported in --stdin mode");
 968                 if (handle_revision_arg(line, revs, 0, 1))
 969                         die("bad revision '%s'", line);
 970         }
 971 }
 972
 973 static void add_grep(struct rev_info *revs, const char *ptn, enum grep_pat_token what)
 974 {
 975         append_grep_pattern(&revs->grep_filter, ptn, "command line", 0, what);
 976 }
 977
 978 static void add_header_grep(struct rev_info *revs, enum grep_header_field field, const char *pattern)
 979 {
 980         append_header_grep_pattern(&revs->grep_filter, field, pattern);
 981 }
 982
 983 static void add_message_grep(struct rev_info *revs, const char *pattern)
 984 {
 985         add_grep(revs, pattern, GREP_PATTERN_BODY);
 986 }
 987
 988 static int handle_revision_opt(struct rev_info *revs, int argc, const char **argv,
 989                                int *unkc, const char **unkv)
 990 {
 991         const char *arg = argv[0];
 992
 993         /* pseudo revision arguments */
 994         if (!strcmp(arg, "--all") || !strcmp(arg, "--branches") ||
 995             !strcmp(arg, "--tags") || !strcmp(arg, "--remotes") ||
 996             !strcmp(arg, "--reflog") || !strcmp(arg, "--not") ||
 997             !strcmp(arg, "--no-walk") || !strcmp(arg, "--do-walk"))
 998         {
 999                 unkv[(*unkc)++] = arg;
1000                 return 1;
1001         }
1002
1003         if (!prefixcmp(arg, "--max-count=")) {
1004                 revs->max_count = atoi(arg + 12);
1005         } else if (!prefixcmp(arg, "--skip=")) {
1006                 revs->skip_count = atoi(arg + 7);
1007         } else if ((*arg == '-') && isdigit(arg[1])) {
1008         /* accept -<digit>, like traditional "head" */
1009                 revs->max_count = atoi(arg + 1);
1010         } else if (!strcmp(arg, "-n")) {
1011                 if (argc <= 1)
1012                         return error("-n requires an argument");
1013                 revs->max_count = atoi(argv[1]);
1014                 return 2;
1015         } else if (!prefixcmp(arg, "-n")) {
1016                 revs->max_count = atoi(arg + 2);
1017         } else if (!prefixcmp(arg, "--max-age=")) {
1018                 revs->max_age = atoi(arg + 10);
1019         } else if (!prefixcmp(arg, "--since=")) {
1020                 revs->max_age = approxidate(arg + 8);
1021         } else if (!prefixcmp(arg, "--after=")) {
1022                 revs->max_age = approxidate(arg + 8);
1023         } else if (!prefixcmp(arg, "--min-age=")) {
1024                 revs->min_age = atoi(arg + 10);
1025         } else if (!prefixcmp(arg, "--before=")) {
1026                 revs->min_age = approxidate(arg + 9);
1027         } else if (!prefixcmp(arg, "--until=")) {
1028                 revs->min_age = approxidate(arg + 8);
1029         } else if (!strcmp(arg, "--first-parent")) {
1030                 revs->first_parent_only = 1;
1031         } else if (!strcmp(arg, "-g") || !strcmp(arg, "--walk-reflogs")) {
1032                 init_reflog_walk(&revs->reflog_info);
1033         } else if (!strcmp(arg, "--default")) {
1034                 if (argc <= 1)
1035                         return error("bad --default argument");
1036                 revs->def = argv[1];
1037                 return 2;
1038         } else if (!strcmp(arg, "--merge")) {
1039                 revs->show_merge = 1;
1040         } else if (!strcmp(arg, "--topo-order")) {
1041                 revs->lifo = 1;
1042                 revs->topo_order = 1;
1043         } else if (!strcmp(arg, "--simplify-merges")) {
1044                 revs->simplify_merges = 1;
1045                 revs->rewrite_parents = 1;
1046                 revs->simplify_history = 0;
1047                 revs->limited = 1;
1048         } else if (!strcmp(arg, "--simplify-by-decoration")) {
1049                 revs->simplify_merges = 1;
1050                 revs->rewrite_parents = 1;
1051                 revs->simplify_history = 0;
1052                 revs->simplify_by_decoration = 1;
1053                 revs->limited = 1;
1054                 revs->prune = 1;
1055                 load_ref_decorations();
1056         } else if (!strcmp(arg, "--date-order")) {
1057                 revs->lifo = 0;
1058                 revs->topo_order = 1;
1059         } else if (!prefixcmp(arg, "--early-output")) {
1060                 int count = 100;
1061                 switch (arg[14]) {
1062                 case '=':
1063                         count = atoi(arg+15);
1064                         /* Fallthrough */
1065                 case 0:
1066                         revs->topo_order = 1;
1067                        revs->early_output = count;
1068                 }
1069         } else if (!strcmp(arg, "--parents")) {
1070                 revs->rewrite_parents = 1;
1071                 revs->print_parents = 1;
1072         } else if (!strcmp(arg, "--dense")) {
1073                 revs->dense = 1;
1074         } else if (!strcmp(arg, "--sparse")) {
1075                 revs->dense = 0;
1076         } else if (!strcmp(arg, "--show-all")) {
1077                 revs->show_all = 1;
1078         } else if (!strcmp(arg, "--remove-empty")) {
1079                 revs->remove_empty_trees = 1;
1080         } else if (!strcmp(arg, "--no-merges")) {
1081                 revs->no_merges = 1;
1082         } else if (!strcmp(arg, "--boundary")) {
1083                 revs->boundary = 1;
1084         } else if (!strcmp(arg, "--left-right")) {
1085                 revs->left_right = 1;
1086         } else if (!strcmp(arg, "--cherry-pick")) {
1087                 revs->cherry_pick = 1;
1088                 revs->limited = 1;
1089         } else if (!strcmp(arg, "--objects")) {
1090                 revs->tag_objects = 1;
1091                 revs->tree_objects = 1;
1092                 revs->blob_objects = 1;
1093         } else if (!strcmp(arg, "--objects-edge")) {
1094                 revs->tag_objects = 1;
1095                 revs->tree_objects = 1;
1096                 revs->blob_objects = 1;
1097                 revs->edge_hint = 1;
1098         } else if (!strcmp(arg, "--unpacked")) {
1099                 revs->unpacked = 1;
1100         } else if (!prefixcmp(arg, "--unpacked=")) {
1101                 die("--unpacked=<packfile> no longer supported.");
1102         } else if (!strcmp(arg, "-r")) {
1103                 revs->diff = 1;
1104                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1105         } else if (!strcmp(arg, "-t")) {
1106                 revs->diff = 1;
1107                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1108                 DIFF_OPT_SET(&revs->diffopt, TREE_IN_RECURSIVE);
1109         } else if (!strcmp(arg, "-m")) {
1110                 revs->ignore_merges = 0;
1111         } else if (!strcmp(arg, "-c")) {
1112                 revs->diff = 1;
1113                 revs->dense_combined_merges = 0;
1114                 revs->combine_merges = 1;
1115         } else if (!strcmp(arg, "--cc")) {
1116                 revs->diff = 1;
1117                 revs->dense_combined_merges = 1;
1118                 revs->combine_merges = 1;
1119         } else if (!strcmp(arg, "-v")) {
1120                 revs->verbose_header = 1;
1121         } else if (!strcmp(arg, "--pretty")) {
1122                 revs->verbose_header = 1;
1123                 get_commit_format(arg+8, revs);
1124         } else if (!prefixcmp(arg, "--pretty=") || !prefixcmp(arg, "--format=")) {
1125                 revs->verbose_header = 1;
1126                 get_commit_format(arg+9, revs);
1127         } else if (!strcmp(arg, "--oneline")) {
1128                 revs->verbose_header = 1;
1129                 get_commit_format("oneline", revs);
1130                 revs->abbrev_commit = 1;
1131         } else if (!strcmp(arg, "--graph")) {
1132                 revs->topo_order = 1;
1133                 revs->rewrite_parents = 1;
1134                 revs->graph = graph_init(revs);
1135         } else if (!strcmp(arg, "--root")) {
1136                 revs->show_root_diff = 1;
1137         } else if (!strcmp(arg, "--no-commit-id")) {
1138                 revs->no_commit_id = 1;
1139         } else if (!strcmp(arg, "--always")) {
1140                 revs->always_show_header = 1;
1141         } else if (!strcmp(arg, "--no-abbrev")) {
1142                 revs->abbrev = 0;
1143         } else if (!strcmp(arg, "--abbrev")) {
1144                 revs->abbrev = DEFAULT_ABBREV;
1145         } else if (!prefixcmp(arg, "--abbrev=")) {
1146                 revs->abbrev = strtoul(arg + 9, NULL, 10);
1147                 if (revs->abbrev < MINIMUM_ABBREV)
1148                         revs->abbrev = MINIMUM_ABBREV;
1149                 else if (revs->abbrev > 40)
1150                         revs->abbrev = 40;
1151         } else if (!strcmp(arg, "--abbrev-commit")) {
1152                 revs->abbrev_commit = 1;
1153         } else if (!strcmp(arg, "--full-diff")) {
1154                 revs->diff = 1;
1155                 revs->full_diff = 1;
1156         } else if (!strcmp(arg, "--full-history")) {
1157                 revs->simplify_history = 0;
1158         } else if (!strcmp(arg, "--relative-date")) {
1159                 revs->date_mode = DATE_RELATIVE;
1160         } else if (!strncmp(arg, "--date=", 7)) {
1161                 revs->date_mode = parse_date_format(arg + 7);
1162         } else if (!strcmp(arg, "--log-size")) {
1163                 revs->show_log_size = 1;
1164         }
1165         /*
1166          * Grepping the commit log
1167          */
1168         else if (!prefixcmp(arg, "--author=")) {
1169                 add_header_grep(revs, GREP_HEADER_AUTHOR, arg+9);
1170         } else if (!prefixcmp(arg, "--committer=")) {
1171                 add_header_grep(revs, GREP_HEADER_COMMITTER, arg+12);
1172         } else if (!prefixcmp(arg, "--grep=")) {
1173                 add_message_grep(revs, arg+7);
1174         } else if (!strcmp(arg, "--extended-regexp") || !strcmp(arg, "-E")) {
1175                 revs->grep_filter.regflags |= REG_EXTENDED;
1176         } else if (!strcmp(arg, "--regexp-ignore-case") || !strcmp(arg, "-i")) {
1177                 revs->grep_filter.regflags |= REG_ICASE;
1178         } else if (!strcmp(arg, "--fixed-strings") || !strcmp(arg, "-F")) {
1179                 revs->grep_filter.fixed = 1;
1180         } else if (!strcmp(arg, "--all-match")) {
1181                 revs->grep_filter.all_match = 1;
1182         } else if (!prefixcmp(arg, "--encoding=")) {
1183                 arg += 11;
1184                 if (strcmp(arg, "none"))
1185                         git_log_output_encoding = xstrdup(arg);
1186                 else
1187                         git_log_output_encoding = "";
1188         } else if (!strcmp(arg, "--reverse")) {
1189                 revs->reverse ^= 1;
1190         } else if (!strcmp(arg, "--children")) {
1191                 revs->children.name = "children";
1192                 revs->limited = 1;
1193         } else {
1194                 int opts = diff_opt_parse(&revs->diffopt, argv, argc);
1195                 if (!opts)
1196                         unkv[(*unkc)++] = arg;
1197                 return opts;
1198         }
1199
1200         return 1;
1201 }
1202
1203 void parse_revision_opt(struct rev_info *revs, struct parse_opt_ctx_t *ctx,
1204                         const struct option *options,
1205                         const char * const usagestr[])
1206 {
1207         int n = handle_revision_opt(revs, ctx->argc, ctx->argv,
1208                                     &ctx->cpidx, ctx->out);
1209         if (n <= 0) {
1210                 error("unknown option `%s'", ctx->argv[0]);
1211                 usage_with_options(usagestr, options);
1212         }
1213         ctx->argv += n;
1214         ctx->argc -= n;
1215 }
1216
1217 /*
1218  * Parse revision information, filling in the "rev_info" structure,
1219  * and removing the used arguments from the argument list.
1220  *
1221  * Returns the number of arguments left that weren't recognized
1222  * (which are also moved to the head of the argument list)
1223  */
1224 int setup_revisions(int argc, const char **argv, struct rev_info *revs, const char *def)
1225 {
1226         int i, flags, left, seen_dashdash;
1227
1228         /* First, search for "--" */
1229         seen_dashdash = 0;
1230         for (i = 1; i < argc; i++) {
1231                 const char *arg = argv[i];
1232                 if (strcmp(arg, "--"))
1233                         continue;
1234                 argv[i] = NULL;
1235                 argc = i;
1236                 if (argv[i + 1])
1237                         revs->prune_data = get_pathspec(revs->prefix, argv + i + 1);
1238                 seen_dashdash = 1;
1239                 break;
1240         }
1241
1242         /* Second, deal with arguments and options */
1243         flags = 0;
1244         for (left = i = 1; i < argc; i++) {
1245                 const char *arg = argv[i];
1246                 if (*arg == '-') {
1247                         int opts;
1248
1249                         if (!strcmp(arg, "--all")) {
1250                                 handle_refs(revs, flags, for_each_ref);
1251                                 handle_refs(revs, flags, head_ref);
1252                                 continue;
1253                         }
1254                         if (!strcmp(arg, "--branches")) {
1255                                 handle_refs(revs, flags, for_each_branch_ref);
1256                                 continue;
1257                         }
1258                         if (!strcmp(arg, "--tags")) {
1259                                 handle_refs(revs, flags, for_each_tag_ref);
1260                                 continue;
1261                         }
1262                         if (!strcmp(arg, "--remotes")) {
1263                                 handle_refs(revs, flags, for_each_remote_ref);
1264                                 continue;
1265                         }
1266                         if (!strcmp(arg, "--reflog")) {
1267                                 handle_reflog(revs, flags);
1268                                 continue;
1269                         }
1270                         if (!strcmp(arg, "--not")) {
1271                                 flags ^= UNINTERESTING;
1272                                 continue;
1273                         }
1274                         if (!strcmp(arg, "--no-walk")) {
1275                                 revs->no_walk = 1;
1276                                 continue;
1277                         }
1278                         if (!strcmp(arg, "--do-walk")) {
1279                                 revs->no_walk = 0;
1280                                 continue;
1281                         }
1282
1283                         opts = handle_revision_opt(revs, argc - i, argv + i, &left, argv);
1284                         if (opts > 0) {
1285                                 i += opts - 1;
1286                                 continue;
1287                         }
1288                         if (opts < 0)
1289                                 exit(128);
1290                         continue;
1291                 }
1292
1293                 if (handle_revision_arg(arg, revs, flags, seen_dashdash)) {
1294                         int j;
1295                         if (seen_dashdash || *arg == '^')
1296                                 die("bad revision '%s'", arg);
1297
1298                         /* If we didn't have a "--":
1299                          * (1) all filenames must exist;
1300                          * (2) all rev-args must not be interpretable
1301                          *     as a valid filename.
1302                          * but the latter we have checked in the main loop.
1303                          */
1304                         for (j = i; j < argc; j++)
1305                                 verify_filename(revs->prefix, argv[j]);
1306
1307                         revs->prune_data = get_pathspec(revs->prefix,
1308                                                         argv + i);
1309                         break;
1310                 }
1311         }
1312
1313         if (revs->def == NULL)
1314                 revs->def = def;
1315         if (revs->show_merge)
1316                 prepare_show_merge(revs);
1317         if (revs->def && !revs->pending.nr) {
1318                 unsigned char sha1[20];
1319                 struct object *object;
1320                 unsigned mode;
1321                 if (get_sha1_with_mode(revs->def, sha1, &mode))
1322                         die("bad default revision '%s'", revs->def);
1323                 object = get_reference(revs, revs->def, sha1, 0);
1324                 add_pending_object_with_mode(revs, object, revs->def, mode);
1325         }
1326
1327         /* Did the user ask for any diff output? Run the diff! */
1328         if (revs->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT)
1329                 revs->diff = 1;
1330
1331         /* Pickaxe, diff-filter and rename following need diffs */
1332         if (revs->diffopt.pickaxe ||
1333             revs->diffopt.filter ||
1334             DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1335                 revs->diff = 1;
1336
1337         if (revs->topo_order)
1338                 revs->limited = 1;
1339
1340         if (revs->prune_data) {
1341                 diff_tree_setup_paths(revs->prune_data, &revs->pruning);
1342                 /* Can't prune commits with rename following: the paths change.. */
1343                 if (!DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1344                         revs->prune = 1;
1345                 if (!revs->full_diff)
1346                         diff_tree_setup_paths(revs->prune_data, &revs->diffopt);
1347         }
1348         if (revs->combine_merges) {
1349                 revs->ignore_merges = 0;
1350                 if (revs->dense_combined_merges && !revs->diffopt.output_format)
1351                         revs->diffopt.output_format = DIFF_FORMAT_PATCH;
1352         }
1353         revs->diffopt.abbrev = revs->abbrev;
1354         if (diff_setup_done(&revs->diffopt) < 0)
1355                 die("diff_setup_done failed");
1356
1357         compile_grep_patterns(&revs->grep_filter);
1358
1359         if (revs->reverse && revs->reflog_info)
1360                 die("cannot combine --reverse with --walk-reflogs");
1361         if (revs->rewrite_parents && revs->children.name)
1362                 die("cannot combine --parents and --children");
1363
1364         /*
1365          * Limitations on the graph functionality
1366          */
1367         if (revs->reverse && revs->graph)
1368                 die("cannot combine --reverse with --graph");
1369
1370         if (revs->reflog_info && revs->graph)
1371                 die("cannot combine --walk-reflogs with --graph");
1372
1373         return left;
1374 }
1375
1376 static void add_child(struct rev_info *revs, struct commit *parent, struct commit *child)
1377 {
1378         struct commit_list *l = xcalloc(1, sizeof(*l));
1379
1380         l->item = child;
1381         l->next = add_decoration(&revs->children, &parent->object, l);
1382 }
1383
1384 static int remove_duplicate_parents(struct commit *commit)
1385 {
1386         struct commit_list **pp, *p;
1387         int surviving_parents;
1388
1389         /* Examine existing parents while marking ones we have seen... */
1390         pp = &commit->parents;
1391         while ((p = *pp) != NULL) {
1392                 struct commit *parent = p->item;
1393                 if (parent->object.flags & TMP_MARK) {
1394                         *pp = p->next;
1395                         continue;
1396                 }
1397                 parent->object.flags |= TMP_MARK;
1398                 pp = &p->next;
1399         }
1400         /* count them while clearing the temporary mark */
1401         surviving_parents = 0;
1402         for (p = commit->parents; p; p = p->next) {
1403                 p->item->object.flags &= ~TMP_MARK;
1404                 surviving_parents++;
1405         }
1406         return surviving_parents;
1407 }
1408
1409 struct merge_simplify_state {
1410         struct commit *simplified;
1411 };
1412
1413 static struct merge_simplify_state *locate_simplify_state(struct rev_info *revs, struct commit *commit)
1414 {
1415         struct merge_simplify_state *st;
1416
1417         st = lookup_decoration(&revs->merge_simplification, &commit->object);
1418         if (!st) {
1419                 st = xcalloc(1, sizeof(*st));
1420                 add_decoration(&revs->merge_simplification, &commit->object, st);
1421         }
1422         return st;
1423 }
1424
1425 static struct commit_list **simplify_one(struct rev_info *revs, struct commit *commit, struct commit_list **tail)
1426 {
1427         struct commit_list *p;
1428         struct merge_simplify_state *st, *pst;
1429         int cnt;
1430
1431         st = locate_simplify_state(revs, commit);
1432
1433         /*
1434          * Have we handled this one?
1435          */
1436         if (st->simplified)
1437                 return tail;
1438
1439         /*
1440          * An UNINTERESTING commit simplifies to itself, so does a
1441          * root commit.  We do not rewrite parents of such commit
1442          * anyway.
1443          */
1444         if ((commit->object.flags & UNINTERESTING) || !commit->parents) {
1445                 st->simplified = commit;
1446                 return tail;
1447         }
1448
1449         /*
1450          * Do we know what commit all of our parents should be rewritten to?
1451          * Otherwise we are not ready to rewrite this one yet.
1452          */
1453         for (cnt = 0, p = commit->parents; p; p = p->next) {
1454                 pst = locate_simplify_state(revs, p->item);
1455                 if (!pst->simplified) {
1456                         tail = &commit_list_insert(p->item, tail)->next;
1457                         cnt++;
1458                 }
1459         }
1460         if (cnt) {
1461                 tail = &commit_list_insert(commit, tail)->next;
1462                 return tail;
1463         }
1464
1465         /*
1466          * Rewrite our list of parents.
1467          */
1468         for (p = commit->parents; p; p = p->next) {
1469                 pst = locate_simplify_state(revs, p->item);
1470                 p->item = pst->simplified;
1471         }
1472         cnt = remove_duplicate_parents(commit);
1473
1474         /*
1475          * It is possible that we are a merge and one side branch
1476          * does not have any commit that touches the given paths;
1477          * in such a case, the immediate parents will be rewritten
1478          * to different commits.
1479          *
1480          *      o----X          X: the commit we are looking at;
1481          *     /    /           o: a commit that touches the paths;
1482          * ---o----'
1483          *
1484          * Further reduce the parents by removing redundant parents.
1485          */
1486         if (1 < cnt) {
1487                 struct commit_list *h = reduce_heads(commit->parents);
1488                 cnt = commit_list_count(h);
1489                 free_commit_list(commit->parents);
1490                 commit->parents = h;
1491         }
1492
1493         /*
1494          * A commit simplifies to itself if it is a root, if it is
1495          * UNINTERESTING, if it touches the given paths, or if it is a
1496          * merge and its parents simplifies to more than one commits
1497          * (the first two cases are already handled at the beginning of
1498          * this function).
1499          *
1500          * Otherwise, it simplifies to what its sole parent simplifies to.
1501          */
1502         if (!cnt ||
1503             (commit->object.flags & UNINTERESTING) ||
1504             !(commit->object.flags & TREESAME) ||
1505             (1 < cnt))
1506                 st->simplified = commit;
1507         else {
1508                 pst = locate_simplify_state(revs, commit->parents->item);
1509                 st->simplified = pst->simplified;
1510         }
1511         return tail;
1512 }
1513
1514 static void simplify_merges(struct rev_info *revs)
1515 {
1516         struct commit_list *list;
1517         struct commit_list *yet_to_do, **tail;
1518
1519         if (!revs->topo_order)
1520                 sort_in_topological_order(&revs->commits, revs->lifo);
1521         if (!revs->prune)
1522                 return;
1523
1524         /* feed the list reversed */
1525         yet_to_do = NULL;
1526         for (list = revs->commits; list; list = list->next)
1527                 commit_list_insert(list->item, &yet_to_do);
1528         while (yet_to_do) {
1529                 list = yet_to_do;
1530                 yet_to_do = NULL;
1531                 tail = &yet_to_do;
1532                 while (list) {
1533                         struct commit *commit = list->item;
1534                         struct commit_list *next = list->next;
1535                         free(list);
1536                         list = next;
1537                         tail = simplify_one(revs, commit, tail);
1538                 }
1539         }
1540
1541         /* clean up the result, removing the simplified ones */
1542         list = revs->commits;
1543         revs->commits = NULL;
1544         tail = &revs->commits;
1545         while (list) {
1546                 struct commit *commit = list->item;
1547                 struct commit_list *next = list->next;
1548                 struct merge_simplify_state *st;
1549                 free(list);
1550                 list = next;
1551                 st = locate_simplify_state(revs, commit);
1552                 if (st->simplified == commit)
1553                         tail = &commit_list_insert(commit, tail)->next;
1554         }
1555 }
1556
1557 static void set_children(struct rev_info *revs)
1558 {
1559         struct commit_list *l;
1560         for (l = revs->commits; l; l = l->next) {
1561                 struct commit *commit = l->item;
1562                 struct commit_list *p;
1563
1564                 for (p = commit->parents; p; p = p->next)
1565                         add_child(revs, p->item, commit);
1566         }
1567 }
1568
1569 int prepare_revision_walk(struct rev_info *revs)
1570 {
1571         int nr = revs->pending.nr;
1572         struct object_array_entry *e, *list;
1573
1574         e = list = revs->pending.objects;
1575         revs->pending.nr = 0;
1576         revs->pending.alloc = 0;
1577         revs->pending.objects = NULL;
1578         while (--nr >= 0) {
1579                 struct commit *commit = handle_commit(revs, e->item, e->name);
1580                 if (commit) {
1581                         if (!(commit->object.flags & SEEN)) {
1582                                 commit->object.flags |= SEEN;
1583                                 insert_by_date(commit, &revs->commits);
1584                         }
1585                 }
1586                 e++;
1587         }
1588         free(list);
1589
1590         if (revs->no_walk)
1591                 return 0;
1592         if (revs->limited)
1593                 if (limit_list(revs) < 0)
1594                         return -1;
1595         if (revs->topo_order)
1596                 sort_in_topological_order(&revs->commits, revs->lifo);
1597         if (revs->simplify_merges)
1598                 simplify_merges(revs);
1599         if (revs->children.name)
1600                 set_children(revs);
1601         return 0;
1602 }
1603
1604 enum rewrite_result {
1605         rewrite_one_ok,
1606         rewrite_one_noparents,
1607         rewrite_one_error,
1608 };
1609
1610 static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp)
1611 {
1612         struct commit_list *cache = NULL;
1613
1614         for (;;) {
1615                 struct commit *p = *pp;
1616                 if (!revs->limited)
1617                         if (add_parents_to_list(revs, p, &revs->commits, &cache) < 0)
1618                                 return rewrite_one_error;
1619                 if (p->parents && p->parents->next)
1620                         return rewrite_one_ok;
1621                 if (p->object.flags & UNINTERESTING)
1622                         return rewrite_one_ok;
1623                 if (!(p->object.flags & TREESAME))
1624                         return rewrite_one_ok;
1625                 if (!p->parents)
1626                         return rewrite_one_noparents;
1627                 *pp = p->parents->item;
1628         }
1629 }
1630
1631 static int rewrite_parents(struct rev_info *revs, struct commit *commit)
1632 {
1633         struct commit_list **pp = &commit->parents;
1634         while (*pp) {
1635                 struct commit_list *parent = *pp;
1636                 switch (rewrite_one(revs, &parent->item)) {
1637                 case rewrite_one_ok:
1638                         break;
1639                 case rewrite_one_noparents:
1640                         *pp = parent->next;
1641                         continue;
1642                 case rewrite_one_error:
1643                         return -1;
1644                 }
1645                 pp = &parent->next;
1646         }
1647         remove_duplicate_parents(commit);
1648         return 0;
1649 }
1650
1651 static int commit_match(struct commit *commit, struct rev_info *opt)
1652 {
1653         if (!opt->grep_filter.pattern_list)
1654                 return 1;
1655         return grep_buffer(&opt->grep_filter,
1656                            NULL, /* we say nothing, not even filename */
1657                            commit->buffer, strlen(commit->buffer));
1658 }
1659
1660 static inline int want_ancestry(struct rev_info *revs)
1661 {
1662         return (revs->rewrite_parents || revs->children.name);
1663 }
1664
1665 enum commit_action simplify_commit(struct rev_info *revs, struct commit *commit)
1666 {
1667         if (commit->object.flags & SHOWN)
1668                 return commit_ignore;
1669         if (revs->unpacked && has_sha1_pack(commit->object.sha1))
1670                 return commit_ignore;
1671         if (revs->show_all)
1672                 return commit_show;
1673         if (commit->object.flags & UNINTERESTING)
1674                 return commit_ignore;
1675         if (revs->min_age != -1 && (commit->date > revs->min_age))
1676                 return commit_ignore;
1677         if (revs->no_merges && commit->parents && commit->parents->next)
1678                 return commit_ignore;
1679         if (!commit_match(commit, revs))
1680                 return commit_ignore;
1681         if (revs->prune && revs->dense) {
1682                 /* Commit without changes? */
1683                 if (commit->object.flags & TREESAME) {
1684                         /* drop merges unless we want parenthood */
1685                         if (!want_ancestry(revs))
1686                                 return commit_ignore;
1687                         /* non-merge - always ignore it */
1688                         if (!commit->parents || !commit->parents->next)
1689                                 return commit_ignore;
1690                 }
1691                 if (want_ancestry(revs) && rewrite_parents(revs, commit) < 0)
1692                         return commit_error;
1693         }
1694         return commit_show;
1695 }
1696
1697 static struct commit *get_revision_1(struct rev_info *revs)
1698 {
1699         if (!revs->commits)
1700                 return NULL;
1701
1702         do {
1703                 struct commit_list *entry = revs->commits;
1704                 struct commit *commit = entry->item;
1705
1706                 revs->commits = entry->next;
1707                 free(entry);
1708
1709                 if (revs->reflog_info)
1710                         fake_reflog_parent(revs->reflog_info, commit);
1711
1712                 /*
1713                  * If we haven't done the list limiting, we need to look at
1714                  * the parents here. We also need to do the date-based limiting
1715                  * that we'd otherwise have done in limit_list().
1716                  */
1717                 if (!revs->limited) {
1718                         if (revs->max_age != -1 &&
1719                             (commit->date < revs->max_age))
1720                                 continue;
1721                         if (add_parents_to_list(revs, commit, &revs->commits, NULL) < 0)
1722                                 die("Failed to traverse parents of commit %s",
1723                                     sha1_to_hex(commit->object.sha1));
1724                 }
1725
1726                 switch (simplify_commit(revs, commit)) {
1727                 case commit_ignore:
1728                         continue;
1729                 case commit_error:
1730                         die("Failed to simplify parents of commit %s",
1731                             sha1_to_hex(commit->object.sha1));
1732                 default:
1733                         return commit;
1734                 }
1735         } while (revs->commits);
1736         return NULL;
1737 }
1738
1739 static void gc_boundary(struct object_array *array)
1740 {
1741         unsigned nr = array->nr;
1742         unsigned alloc = array->alloc;
1743         struct object_array_entry *objects = array->objects;
1744
1745         if (alloc <= nr) {
1746                 unsigned i, j;
1747                 for (i = j = 0; i < nr; i++) {
1748                         if (objects[i].item->flags & SHOWN)
1749                                 continue;
1750                         if (i != j)
1751                                 objects[j] = objects[i];
1752                         j++;
1753                 }
1754                 for (i = j; i < nr; i++)
1755                         objects[i].item = NULL;
1756                 array->nr = j;
1757         }
1758 }
1759
1760 static void create_boundary_commit_list(struct rev_info *revs)
1761 {
1762         unsigned i;
1763         struct commit *c;
1764         struct object_array *array = &revs->boundary_commits;
1765         struct object_array_entry *objects = array->objects;
1766
1767         /*
1768          * If revs->commits is non-NULL at this point, an error occurred in
1769          * get_revision_1().  Ignore the error and continue printing the
1770          * boundary commits anyway.  (This is what the code has always
1771          * done.)
1772          */
1773         if (revs->commits) {
1774                 free_commit_list(revs->commits);
1775                 revs->commits = NULL;
1776         }
1777
1778         /*
1779          * Put all of the actual boundary commits from revs->boundary_commits
1780          * into revs->commits
1781          */
1782         for (i = 0; i < array->nr; i++) {
1783                 c = (struct commit *)(objects[i].item);
1784                 if (!c)
1785                         continue;
1786                 if (!(c->object.flags & CHILD_SHOWN))
1787                         continue;
1788                 if (c->object.flags & (SHOWN | BOUNDARY))
1789                         continue;
1790                 c->object.flags |= BOUNDARY;
1791                 commit_list_insert(c, &revs->commits);
1792         }
1793
1794         /*
1795          * If revs->topo_order is set, sort the boundary commits
1796          * in topological order
1797          */
1798         sort_in_topological_order(&revs->commits, revs->lifo);
1799 }
1800
1801 static struct commit *get_revision_internal(struct rev_info *revs)
1802 {
1803         struct commit *c = NULL;
1804         struct commit_list *l;
1805
1806         if (revs->boundary == 2) {
1807                 /*
1808                  * All of the normal commits have already been returned,
1809                  * and we are now returning boundary commits.
1810                  * create_boundary_commit_list() has populated
1811                  * revs->commits with the remaining commits to return.
1812                  */
1813                 c = pop_commit(&revs->commits);
1814                 if (c)
1815                         c->object.flags |= SHOWN;
1816                 return c;
1817         }
1818
1819         /*
1820          * Now pick up what they want to give us
1821          */
1822         c = get_revision_1(revs);
1823         if (c) {
1824                 while (0 < revs->skip_count) {
1825                         revs->skip_count--;
1826                         c = get_revision_1(revs);
1827                         if (!c)
1828                                 break;
1829                 }
1830         }
1831
1832         /*
1833          * Check the max_count.
1834          */
1835         switch (revs->max_count) {
1836         case -1:
1837                 break;
1838         case 0:
1839                 c = NULL;
1840                 break;
1841         default:
1842                 revs->max_count--;
1843         }
1844
1845         if (c)
1846                 c->object.flags |= SHOWN;
1847
1848         if (!revs->boundary) {
1849                 return c;
1850         }
1851
1852         if (!c) {
1853                 /*
1854                  * get_revision_1() runs out the commits, and
1855                  * we are done computing the boundaries.
1856                  * switch to boundary commits output mode.
1857                  */
1858                 revs->boundary = 2;
1859
1860                 /*
1861                  * Update revs->commits to contain the list of
1862                  * boundary commits.
1863                  */
1864                 create_boundary_commit_list(revs);
1865
1866                 return get_revision_internal(revs);
1867         }
1868
1869         /*
1870          * boundary commits are the commits that are parents of the
1871          * ones we got from get_revision_1() but they themselves are
1872          * not returned from get_revision_1().  Before returning
1873          * 'c', we need to mark its parents that they could be boundaries.
1874          */
1875
1876         for (l = c->parents; l; l = l->next) {
1877                 struct object *p;
1878                 p = &(l->item->object);
1879                 if (p->flags & (CHILD_SHOWN | SHOWN))
1880                         continue;
1881                 p->flags |= CHILD_SHOWN;
1882                 gc_boundary(&revs->boundary_commits);
1883                 add_object_array(p, NULL, &revs->boundary_commits);
1884         }
1885
1886         return c;
1887 }
1888
1889 struct commit *get_revision(struct rev_info *revs)
1890 {
1891         struct commit *c;
1892         struct commit_list *reversed;
1893
1894         if (revs->reverse) {
1895                 reversed = NULL;
1896                 while ((c = get_revision_internal(revs))) {
1897                         commit_list_insert(c, &reversed);
1898                 }
1899                 revs->commits = reversed;
1900                 revs->reverse = 0;
1901                 revs->reverse_output_stage = 1;
1902         }
1903
1904         if (revs->reverse_output_stage)
1905                 return pop_commit(&revs->commits);
1906
1907         c = get_revision_internal(revs);
1908         if (c && revs->graph)
1909                 graph_update(revs->graph, c);
1910         return c;
1911 }