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