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