revision.c

   1 #include "cache.h"
   2 #include "tag.h"
   3 #include "blob.h"
   4 #include "tree.h"
   5 #include "commit.h"
   6 #include "diff.h"
   7 #include "refs.h"
   8 #include "revision.h"
   9 #include "graph.h"
  10 #include "grep.h"
  11 #include "reflog-walk.h"
  12 #include "patch-ids.h"
  13 #include "decorate.h"
  14 #include "log-tree.h"
  15
  16 volatile show_early_output_fn_t show_early_output;
  17
  18 char *path_name(const struct name_path *path, const char *name)
  19 {
  20         const struct name_path *p;
  21         char *n, *m;
  22         int nlen = strlen(name);
  23         int len = nlen + 1;
  24
  25         for (p = path; p; p = p->up) {
  26                 if (p->elem_len)
  27                         len += p->elem_len + 1;
  28         }
  29         n = xmalloc(len);
  30         m = n + len - (nlen + 1);
  31         strcpy(m, name);
  32         for (p = path; p; p = p->up) {
  33                 if (p->elem_len) {
  34                         m -= p->elem_len + 1;
  35                         memcpy(m, p->elem, p->elem_len);
  36                         m[p->elem_len] = '/';
  37                 }
  38         }
  39         return n;
  40 }
  41
  42 void add_object(struct object *obj,
  43                 struct object_array *p,
  44                 struct name_path *path,
  45                 const char *name)
  46 {
  47         add_object_array(obj, path_name(path, name), p);
  48 }
  49
  50 static void mark_blob_uninteresting(struct blob *blob)
  51 {
  52         if (!blob)
  53                 return;
  54         if (blob->object.flags & UNINTERESTING)
  55                 return;
  56         blob->object.flags |= UNINTERESTING;
  57 }
  58
  59 void mark_tree_uninteresting(struct tree *tree)
  60 {
  61         struct tree_desc desc;
  62         struct name_entry entry;
  63         struct object *obj = &tree->object;
  64
  65         if (!tree)
  66                 return;
  67         if (obj->flags & UNINTERESTING)
  68                 return;
  69         obj->flags |= UNINTERESTING;
  70         if (!has_sha1_file(obj->sha1))
  71                 return;
  72         if (parse_tree(tree) < 0)
  73                 die("bad tree %s", sha1_to_hex(obj->sha1));
  74
  75         init_tree_desc(&desc, tree->buffer, tree->size);
  76         while (tree_entry(&desc, &entry)) {
  77                 switch (object_type(entry.mode)) {
  78                 case OBJ_TREE:
  79                         mark_tree_uninteresting(lookup_tree(entry.sha1));
  80                         break;
  81                 case OBJ_BLOB:
  82                         mark_blob_uninteresting(lookup_blob(entry.sha1));
  83                         break;
  84                 default:
  85                         /* Subproject commit - not in this repository */
  86                         break;
  87                 }
  88         }
  89
  90         /*
  91          * We don't care about the tree any more
  92          * after it has been marked uninteresting.
  93          */
  94         free(tree->buffer);
  95         tree->buffer = NULL;
  96 }
  97
  98 void mark_parents_uninteresting(struct commit *commit)
  99 {
 100         struct commit_list *parents = commit->parents;
 101
 102         while (parents) {
 103                 struct commit *commit = parents->item;
 104                 if (!(commit->object.flags & UNINTERESTING)) {
 105                         commit->object.flags |= UNINTERESTING;
 106
 107                         /*
 108                          * Normally we haven't parsed the parent
 109                          * yet, so we won't have a parent of a parent
 110                          * here. However, it may turn out that we've
 111                          * reached this commit some other way (where it
 112                          * wasn't uninteresting), in which case we need
 113                          * to mark its parents recursively too..
 114                          */
 115                         if (commit->parents)
 116                                 mark_parents_uninteresting(commit);
 117                 }
 118
 119                 /*
 120                  * A missing commit is ok iff its parent is marked
 121                  * uninteresting.
 122                  *
 123                  * We just mark such a thing parsed, so that when
 124                  * it is popped next time around, we won't be trying
 125                  * to parse it and get an error.
 126                  */
 127                 if (!has_sha1_file(commit->object.sha1))
 128                         commit->object.parsed = 1;
 129                 parents = parents->next;
 130         }
 131 }
 132
 133 static void add_pending_object_with_mode(struct rev_info *revs, struct object *obj, const char *name, unsigned mode)
 134 {
 135         if (revs->no_walk && (obj->flags & UNINTERESTING))
 136                 revs->no_walk = 0;
 137         if (revs->reflog_info && obj->type == OBJ_COMMIT &&
 138                         add_reflog_for_walk(revs->reflog_info,
 139                                 (struct commit *)obj, name))
 140                 return;
 141         add_object_array_with_mode(obj, name, &revs->pending, mode);
 142 }
 143
 144 void add_pending_object(struct rev_info *revs, struct object *obj, const char *name)
 145 {
 146         add_pending_object_with_mode(revs, obj, name, S_IFINVALID);
 147 }
 148
 149 void add_head_to_pending(struct rev_info *revs)
 150 {
 151         unsigned char sha1[20];
 152         struct object *obj;
 153         if (get_sha1("HEAD", sha1))
 154                 return;
 155         obj = parse_object(sha1);
 156         if (!obj)
 157                 return;
 158         add_pending_object(revs, obj, "HEAD");
 159 }
 160
 161 static struct object *get_reference(struct rev_info *revs, const char *name, const unsigned char *sha1, unsigned int flags)
 162 {
 163         struct object *object;
 164
 165         object = parse_object(sha1);
 166         if (!object)
 167                 die("bad object %s", name);
 168         object->flags |= flags;
 169         return object;
 170 }
 171
 172 static struct commit *handle_commit(struct rev_info *revs, struct object *object, const char *name)
 173 {
 174         unsigned long flags = object->flags;
 175
 176         /*
 177          * Tag object? Look what it points to..
 178          */
 179         while (object->type == OBJ_TAG) {
 180                 struct tag *tag = (struct tag *) object;
 181                 if (revs->tag_objects && !(flags & UNINTERESTING))
 182                         add_pending_object(revs, object, tag->tag);
 183                 if (!tag->tagged)
 184                         die("bad tag");
 185                 object = parse_object(tag->tagged->sha1);
 186                 if (!object) {
 187                         if (flags & UNINTERESTING)
 188                                 return NULL;
 189                         die("bad object %s", sha1_to_hex(tag->tagged->sha1));
 190                 }
 191         }
 192
 193         /*
 194          * Commit object? Just return it, we'll do all the complex
 195          * reachability crud.
 196          */
 197         if (object->type == OBJ_COMMIT) {
 198                 struct commit *commit = (struct commit *)object;
 199                 if (parse_commit(commit) < 0)
 200                         die("unable to parse commit %s", name);
 201                 if (flags & UNINTERESTING) {
 202                         commit->object.flags |= UNINTERESTING;
 203                         mark_parents_uninteresting(commit);
 204                         revs->limited = 1;
 205                 }
 206                 if (revs->show_source && !commit->util)
 207                         commit->util = (void *) name;
 208                 return commit;
 209         }
 210
 211         /*
 212          * Tree object? Either mark it uninteresting, or add it
 213          * to the list of objects to look at later..
 214          */
 215         if (object->type == OBJ_TREE) {
 216                 struct tree *tree = (struct tree *)object;
 217                 if (!revs->tree_objects)
 218                         return NULL;
 219                 if (flags & UNINTERESTING) {
 220                         mark_tree_uninteresting(tree);
 221                         return NULL;
 222                 }
 223                 add_pending_object(revs, object, "");
 224                 return NULL;
 225         }
 226
 227         /*
 228          * Blob object? You know the drill by now..
 229          */
 230         if (object->type == OBJ_BLOB) {
 231                 struct blob *blob = (struct blob *)object;
 232                 if (!revs->blob_objects)
 233                         return NULL;
 234                 if (flags & UNINTERESTING) {
 235                         mark_blob_uninteresting(blob);
 236                         return NULL;
 237                 }
 238                 add_pending_object(revs, object, "");
 239                 return NULL;
 240         }
 241         die("%s is unknown object", name);
 242 }
 243
 244 static int everybody_uninteresting(struct commit_list *orig)
 245 {
 246         struct commit_list *list = orig;
 247         while (list) {
 248                 struct commit *commit = list->item;
 249                 list = list->next;
 250                 if (commit->object.flags & UNINTERESTING)
 251                         continue;
 252                 return 0;
 253         }
 254         return 1;
 255 }
 256
 257 /*
 258  * The goal is to get REV_TREE_NEW as the result only if the
 259  * diff consists of all '+' (and no other changes), REV_TREE_OLD
 260  * if the whole diff is removal of old data, and otherwise
 261  * REV_TREE_DIFFERENT (of course if the trees are the same we
 262  * want REV_TREE_SAME).
 263  * That means that once we get to REV_TREE_DIFFERENT, we do not
 264  * have to look any further.
 265  */
 266 static int tree_difference = REV_TREE_SAME;
 267
 268 static void file_add_remove(struct diff_options *options,
 269                     int addremove, unsigned mode,
 270                     const unsigned char *sha1,
 271                     const char *fullpath, unsigned dirty_submodule)
 272 {
 273         int diff = addremove == '+' ? REV_TREE_NEW : REV_TREE_OLD;
 274
 275         tree_difference |= diff;
 276         if (tree_difference == REV_TREE_DIFFERENT)
 277                 DIFF_OPT_SET(options, HAS_CHANGES);
 278 }
 279
 280 static void file_change(struct diff_options *options,
 281                  unsigned old_mode, unsigned new_mode,
 282                  const unsigned char *old_sha1,
 283                  const unsigned char *new_sha1,
 284                  const char *fullpath,
 285                  unsigned old_dirty_submodule, unsigned new_dirty_submodule)
 286 {
 287         tree_difference = REV_TREE_DIFFERENT;
 288         DIFF_OPT_SET(options, HAS_CHANGES);
 289 }
 290
 291 static int rev_compare_tree(struct rev_info *revs, struct commit *parent, struct commit *commit)
 292 {
 293         struct tree *t1 = parent->tree;
 294         struct tree *t2 = commit->tree;
 295
 296         if (!t1)
 297                 return REV_TREE_NEW;
 298         if (!t2)
 299                 return REV_TREE_OLD;
 300
 301         if (revs->simplify_by_decoration) {
 302                 /*
 303                  * If we are simplifying by decoration, then the commit
 304                  * is worth showing if it has a tag pointing at it.
 305                  */
 306                 if (lookup_decoration(&name_decoration, &commit->object))
 307                         return REV_TREE_DIFFERENT;
 308                 /*
 309                  * A commit that is not pointed by a tag is uninteresting
 310                  * if we are not limited by path.  This means that you will
 311                  * see the usual "commits that touch the paths" plus any
 312                  * tagged commit by specifying both --simplify-by-decoration
 313                  * and pathspec.
 314                  */
 315                 if (!revs->prune_data)
 316                         return REV_TREE_SAME;
 317         }
 318
 319         tree_difference = REV_TREE_SAME;
 320         DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
 321         if (diff_tree_sha1(t1->object.sha1, t2->object.sha1, "",
 322                            &revs->pruning) < 0)
 323                 return REV_TREE_DIFFERENT;
 324         return tree_difference;
 325 }
 326
 327 static int rev_same_tree_as_empty(struct rev_info *revs, struct commit *commit)
 328 {
 329         int retval;
 330         void *tree;
 331         unsigned long size;
 332         struct tree_desc empty, real;
 333         struct tree *t1 = commit->tree;
 334
 335         if (!t1)
 336                 return 0;
 337
 338         tree = read_object_with_reference(t1->object.sha1, tree_type, &size, NULL);
 339         if (!tree)
 340                 return 0;
 341         init_tree_desc(&real, tree, size);
 342         init_tree_desc(&empty, "", 0);
 343
 344         tree_difference = REV_TREE_SAME;
 345         DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
 346         retval = diff_tree(&empty, &real, "", &revs->pruning);
 347         free(tree);
 348
 349         return retval >= 0 && (tree_difference == REV_TREE_SAME);
 350 }
 351
 352 static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
 353 {
 354         struct commit_list **pp, *parent;
 355         int tree_changed = 0, tree_same = 0;
 356
 357         /*
 358          * If we don't do pruning, everything is interesting
 359          */
 360         if (!revs->prune)
 361                 return;
 362
 363         if (!commit->tree)
 364                 return;
 365
 366         if (!commit->parents) {
 367                 if (rev_same_tree_as_empty(revs, commit))
 368                         commit->object.flags |= TREESAME;
 369                 return;
 370         }
 371
 372         /*
 373          * Normal non-merge commit? If we don't want to make the
 374          * history dense, we consider it always to be a change..
 375          */
 376         if (!revs->dense && !commit->parents->next)
 377                 return;
 378
 379         pp = &commit->parents;
 380         while ((parent = *pp) != NULL) {
 381                 struct commit *p = parent->item;
 382
 383                 if (parse_commit(p) < 0)
 384                         die("cannot simplify commit %s (because of %s)",
 385                             sha1_to_hex(commit->object.sha1),
 386                             sha1_to_hex(p->object.sha1));
 387                 switch (rev_compare_tree(revs, p, commit)) {
 388                 case REV_TREE_SAME:
 389                         tree_same = 1;
 390                         if (!revs->simplify_history || (p->object.flags & UNINTERESTING)) {
 391                                 /* Even if a merge with an uninteresting
 392                                  * side branch brought the entire change
 393                                  * we are interested in, we do not want
 394                                  * to lose the other branches of this
 395                                  * merge, so we just keep going.
 396                                  */
 397                                 pp = &parent->next;
 398                                 continue;
 399                         }
 400                         parent->next = NULL;
 401                         commit->parents = parent;
 402                         commit->object.flags |= TREESAME;
 403                         return;
 404
 405                 case REV_TREE_NEW:
 406                         if (revs->remove_empty_trees &&
 407                             rev_same_tree_as_empty(revs, p)) {
 408                                 /* We are adding all the specified
 409                                  * paths from this parent, so the
 410                                  * history beyond this parent is not
 411                                  * interesting.  Remove its parents
 412                                  * (they are grandparents for us).
 413                                  * IOW, we pretend this parent is a
 414                                  * "root" commit.
 415                                  */
 416                                 if (parse_commit(p) < 0)
 417                                         die("cannot simplify commit %s (invalid %s)",
 418                                             sha1_to_hex(commit->object.sha1),
 419                                             sha1_to_hex(p->object.sha1));
 420                                 p->parents = NULL;
 421                         }
 422                 /* fallthrough */
 423                 case REV_TREE_OLD:
 424                 case REV_TREE_DIFFERENT:
 425                         tree_changed = 1;
 426                         pp = &parent->next;
 427                         continue;
 428                 }
 429                 die("bad tree compare for commit %s", sha1_to_hex(commit->object.sha1));
 430         }
 431         if (tree_changed && !tree_same)
 432                 return;
 433         commit->object.flags |= TREESAME;
 434 }
 435
 436 static void insert_by_date_cached(struct commit *p, struct commit_list **head,
 437                     struct commit_list *cached_base, struct commit_list **cache)
 438 {
 439         struct commit_list *new_entry;
 440
 441         if (cached_base && p->date < cached_base->item->date)
 442                 new_entry = insert_by_date(p, &cached_base->next);
 443         else
 444                 new_entry = insert_by_date(p, head);
 445
 446         if (cache && (!*cache || p->date < (*cache)->item->date))
 447                 *cache = new_entry;
 448 }
 449
 450 static int add_parents_to_list(struct rev_info *revs, struct commit *commit,
 451                     struct commit_list **list, struct commit_list **cache_ptr)
 452 {
 453         struct commit_list *parent = commit->parents;
 454         unsigned left_flag;
 455         struct commit_list *cached_base = cache_ptr ? *cache_ptr : NULL;
 456
 457         if (commit->object.flags & ADDED)
 458                 return 0;
 459         commit->object.flags |= ADDED;
 460
 461         /*
 462          * If the commit is uninteresting, don't try to
 463          * prune parents - we want the maximal uninteresting
 464          * set.
 465          *
 466          * Normally we haven't parsed the parent
 467          * yet, so we won't have a parent of a parent
 468          * here. However, it may turn out that we've
 469          * reached this commit some other way (where it
 470          * wasn't uninteresting), in which case we need
 471          * to mark its parents recursively too..
 472          */
 473         if (commit->object.flags & UNINTERESTING) {
 474                 while (parent) {
 475                         struct commit *p = parent->item;
 476                         parent = parent->next;
 477                         if (p)
 478                                 p->object.flags |= UNINTERESTING;
 479                         if (parse_commit(p) < 0)
 480                                 continue;
 481                         if (p->parents)
 482                                 mark_parents_uninteresting(p);
 483                         if (p->object.flags & SEEN)
 484                                 continue;
 485                         p->object.flags |= SEEN;
 486                         insert_by_date_cached(p, list, cached_base, cache_ptr);
 487                 }
 488                 return 0;
 489         }
 490
 491         /*
 492          * Ok, the commit wasn't uninteresting. Try to
 493          * simplify the commit history and find the parent
 494          * that has no differences in the path set if one exists.
 495          */
 496         try_to_simplify_commit(revs, commit);
 497
 498         if (revs->no_walk)
 499                 return 0;
 500
 501         left_flag = (commit->object.flags & SYMMETRIC_LEFT);
 502
 503         for (parent = commit->parents; parent; parent = parent->next) {
 504                 struct commit *p = parent->item;
 505
 506                 if (parse_commit(p) < 0)
 507                         return -1;
 508                 if (revs->show_source && !p->util)
 509                         p->util = commit->util;
 510                 p->object.flags |= left_flag;
 511                 if (!(p->object.flags & SEEN)) {
 512                         p->object.flags |= SEEN;
 513                         insert_by_date_cached(p, list, cached_base, cache_ptr);
 514                 }
 515                 if (revs->first_parent_only)
 516                         break;
 517         }
 518         return 0;
 519 }
 520
 521 static void cherry_pick_list(struct commit_list *list, struct rev_info *revs)
 522 {
 523         struct commit_list *p;
 524         int left_count = 0, right_count = 0;
 525         int left_first;
 526         struct patch_ids ids;
 527
 528         /* First count the commits on the left and on the right */
 529         for (p = list; p; p = p->next) {
 530                 struct commit *commit = p->item;
 531                 unsigned flags = commit->object.flags;
 532                 if (flags & BOUNDARY)
 533                         ;
 534                 else if (flags & SYMMETRIC_LEFT)
 535                         left_count++;
 536                 else
 537                         right_count++;
 538         }
 539
 540         left_first = left_count < right_count;
 541         init_patch_ids(&ids);
 542         if (revs->diffopt.nr_paths) {
 543                 ids.diffopts.nr_paths = revs->diffopt.nr_paths;
 544                 ids.diffopts.paths = revs->diffopt.paths;
 545                 ids.diffopts.pathlens = revs->diffopt.pathlens;
 546         }
 547
 548         /* Compute patch-ids for one side */
 549         for (p = list; p; p = p->next) {
 550                 struct commit *commit = p->item;
 551                 unsigned flags = commit->object.flags;
 552
 553                 if (flags & BOUNDARY)
 554                         continue;
 555                 /*
 556                  * If we have fewer left, left_first is set and we omit
 557                  * commits on the right branch in this loop.  If we have
 558                  * fewer right, we skip the left ones.
 559                  */
 560                 if (left_first != !!(flags & SYMMETRIC_LEFT))
 561                         continue;
 562                 commit->util = add_commit_patch_id(commit, &ids);
 563         }
 564
 565         /* Check the other side */
 566         for (p = list; p; p = p->next) {
 567                 struct commit *commit = p->item;
 568                 struct patch_id *id;
 569                 unsigned flags = commit->object.flags;
 570
 571                 if (flags & BOUNDARY)
 572                         continue;
 573                 /*
 574                  * If we have fewer left, left_first is set and we omit
 575                  * commits on the left branch in this loop.
 576                  */
 577                 if (left_first == !!(flags & SYMMETRIC_LEFT))
 578                         continue;
 579
 580                 /*
 581                  * Have we seen the same patch id?
 582                  */
 583                 id = has_commit_patch_id(commit, &ids);
 584                 if (!id)
 585                         continue;
 586                 id->seen = 1;
 587                 commit->object.flags |= SHOWN;
 588         }
 589
 590         /* Now check the original side for seen ones */
 591         for (p = list; p; p = p->next) {
 592                 struct commit *commit = p->item;
 593                 struct patch_id *ent;
 594
 595                 ent = commit->util;
 596                 if (!ent)
 597                         continue;
 598                 if (ent->seen)
 599                         commit->object.flags |= SHOWN;
 600                 commit->util = NULL;
 601         }
 602
 603         free_patch_ids(&ids);
 604 }
 605
 606 /* How many extra uninteresting commits we want to see.. */
 607 #define SLOP 5
 608
 609 static int still_interesting(struct commit_list *src, unsigned long date, int slop)
 610 {
 611         /*
 612          * No source list at all? We're definitely done..
 613          */
 614         if (!src)
 615                 return 0;
 616
 617         /*
 618          * Does the destination list contain entries with a date
 619          * before the source list? Definitely _not_ done.
 620          */
 621         if (date < src->item->date)
 622                 return SLOP;
 623
 624         /*
 625          * Does the source list still have interesting commits in
 626          * it? Definitely not done..
 627          */
 628         if (!everybody_uninteresting(src))
 629                 return SLOP;
 630
 631         /* Ok, we're closing in.. */
 632         return slop-1;
 633 }
 634
 635 static int limit_list(struct rev_info *revs)
 636 {
 637         int slop = SLOP;
 638         unsigned long date = ~0ul;
 639         struct commit_list *list = revs->commits;
 640         struct commit_list *newlist = NULL;
 641         struct commit_list **p = &newlist;
 642
 643         while (list) {
 644                 struct commit_list *entry = list;
 645                 struct commit *commit = list->item;
 646                 struct object *obj = &commit->object;
 647                 show_early_output_fn_t show;
 648
 649                 list = list->next;
 650                 free(entry);
 651
 652                 if (revs->max_age != -1 && (commit->date < revs->max_age))
 653                         obj->flags |= UNINTERESTING;
 654                 if (add_parents_to_list(revs, commit, &list, NULL) < 0)
 655                         return -1;
 656                 if (obj->flags & UNINTERESTING) {
 657                         mark_parents_uninteresting(commit);
 658                         if (revs->show_all)
 659                                 p = &commit_list_insert(commit, p)->next;
 660                         slop = still_interesting(list, date, slop);
 661                         if (slop)
 662                                 continue;
 663                         /* If showing all, add the whole pending list to the end */
 664                         if (revs->show_all)
 665                                 *p = list;
 666                         break;
 667                 }
 668                 if (revs->min_age != -1 && (commit->date > revs->min_age))
 669                         continue;
 670                 date = commit->date;
 671                 p = &commit_list_insert(commit, p)->next;
 672
 673                 show = show_early_output;
 674                 if (!show)
 675                         continue;
 676
 677                 show(revs, newlist);
 678                 show_early_output = NULL;
 679         }
 680         if (revs->cherry_pick)
 681                 cherry_pick_list(newlist, revs);
 682
 683         revs->commits = newlist;
 684         return 0;
 685 }
 686
 687 struct all_refs_cb {
 688         int all_flags;
 689         int warned_bad_reflog;
 690         struct rev_info *all_revs;
 691         const char *name_for_errormsg;
 692 };
 693
 694 static int handle_one_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
 695 {
 696         struct all_refs_cb *cb = cb_data;
 697         struct object *object = get_reference(cb->all_revs, path, sha1,
 698                                               cb->all_flags);
 699         add_pending_object(cb->all_revs, object, path);
 700         return 0;
 701 }
 702
 703 static void handle_refs(struct rev_info *revs, unsigned flags,
 704                 int (*for_each)(each_ref_fn, void *))
 705 {
 706         struct all_refs_cb cb;
 707         cb.all_revs = revs;
 708         cb.all_flags = flags;
 709         for_each(handle_one_ref, &cb);
 710 }
 711
 712 static void handle_one_reflog_commit(unsigned char *sha1, void *cb_data)
 713 {
 714         struct all_refs_cb *cb = cb_data;
 715         if (!is_null_sha1(sha1)) {
 716                 struct object *o = parse_object(sha1);
 717                 if (o) {
 718                         o->flags |= cb->all_flags;
 719                         add_pending_object(cb->all_revs, o, "");
 720                 }
 721                 else if (!cb->warned_bad_reflog) {
 722                         warning("reflog of '%s' references pruned commits",
 723                                 cb->name_for_errormsg);
 724                         cb->warned_bad_reflog = 1;
 725                 }
 726         }
 727 }
 728
 729 static int handle_one_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
 730                 const char *email, unsigned long timestamp, int tz,
 731                 const char *message, void *cb_data)
 732 {
 733         handle_one_reflog_commit(osha1, cb_data);
 734         handle_one_reflog_commit(nsha1, cb_data);
 735         return 0;
 736 }
 737
 738 static int handle_one_reflog(const char *path, const unsigned char *sha1, int flag, void *cb_data)
 739 {
 740         struct all_refs_cb *cb = cb_data;
 741         cb->warned_bad_reflog = 0;
 742         cb->name_for_errormsg = path;
 743         for_each_reflog_ent(path, handle_one_reflog_ent, cb_data);
 744         return 0;
 745 }
 746
 747 static void handle_reflog(struct rev_info *revs, unsigned flags)
 748 {
 749         struct all_refs_cb cb;
 750         cb.all_revs = revs;
 751         cb.all_flags = flags;
 752         for_each_reflog(handle_one_reflog, &cb);
 753 }
 754
 755 static int add_parents_only(struct rev_info *revs, const char *arg, int flags)
 756 {
 757         unsigned char sha1[20];
 758         struct object *it;
 759         struct commit *commit;
 760         struct commit_list *parents;
 761
 762         if (*arg == '^') {
 763                 flags ^= UNINTERESTING;
 764                 arg++;
 765         }
 766         if (get_sha1(arg, sha1))
 767                 return 0;
 768         while (1) {
 769                 it = get_reference(revs, arg, sha1, 0);
 770                 if (it->type != OBJ_TAG)
 771                         break;
 772                 if (!((struct tag*)it)->tagged)
 773                         return 0;
 774                 hashcpy(sha1, ((struct tag*)it)->tagged->sha1);
 775         }
 776         if (it->type != OBJ_COMMIT)
 777                 return 0;
 778         commit = (struct commit *)it;
 779         for (parents = commit->parents; parents; parents = parents->next) {
 780                 it = &parents->item->object;
 781                 it->flags |= flags;
 782                 add_pending_object(revs, it, arg);
 783         }
 784         return 1;
 785 }
 786
 787 void init_revisions(struct rev_info *revs, const char *prefix)
 788 {
 789         memset(revs, 0, sizeof(*revs));
 790
 791         revs->abbrev = DEFAULT_ABBREV;
 792         revs->ignore_merges = 1;
 793         revs->simplify_history = 1;
 794         DIFF_OPT_SET(&revs->pruning, RECURSIVE);
 795         DIFF_OPT_SET(&revs->pruning, QUICK);
 796         revs->pruning.add_remove = file_add_remove;
 797         revs->pruning.change = file_change;
 798         revs->lifo = 1;
 799         revs->dense = 1;
 800         revs->prefix = prefix;
 801         revs->max_age = -1;
 802         revs->min_age = -1;
 803         revs->skip_count = -1;
 804         revs->max_count = -1;
 805
 806         revs->commit_format = CMIT_FMT_DEFAULT;
 807
 808         revs->grep_filter.status_only = 1;
 809         revs->grep_filter.pattern_tail = &(revs->grep_filter.pattern_list);
 810         revs->grep_filter.regflags = REG_NEWLINE;
 811
 812         diff_setup(&revs->diffopt);
 813         if (prefix && !revs->diffopt.prefix) {
 814                 revs->diffopt.prefix = prefix;
 815                 revs->diffopt.prefix_length = strlen(prefix);
 816         }
 817 }
 818
 819 static void add_pending_commit_list(struct rev_info *revs,
 820                                     struct commit_list *commit_list,
 821                                     unsigned int flags)
 822 {
 823         while (commit_list) {
 824                 struct object *object = &commit_list->item->object;
 825                 object->flags |= flags;
 826                 add_pending_object(revs, object, sha1_to_hex(object->sha1));
 827                 commit_list = commit_list->next;
 828         }
 829 }
 830
 831 static void prepare_show_merge(struct rev_info *revs)
 832 {
 833         struct commit_list *bases;
 834         struct commit *head, *other;
 835         unsigned char sha1[20];
 836         const char **prune = NULL;
 837         int i, prune_num = 1; /* counting terminating NULL */
 838
 839         if (get_sha1("HEAD", sha1) || !(head = lookup_commit(sha1)))
 840                 die("--merge without HEAD?");
 841         if (get_sha1("MERGE_HEAD", sha1) || !(other = lookup_commit(sha1)))
 842                 die("--merge without MERGE_HEAD?");
 843         add_pending_object(revs, &head->object, "HEAD");
 844         add_pending_object(revs, &other->object, "MERGE_HEAD");
 845         bases = get_merge_bases(head, other, 1);
 846         add_pending_commit_list(revs, bases, UNINTERESTING);
 847         free_commit_list(bases);
 848         head->object.flags |= SYMMETRIC_LEFT;
 849
 850         if (!active_nr)
 851                 read_cache();
 852         for (i = 0; i < active_nr; i++) {
 853                 struct cache_entry *ce = active_cache[i];
 854                 if (!ce_stage(ce))
 855                         continue;
 856                 if (ce_path_match(ce, revs->prune_data)) {
 857                         prune_num++;
 858                         prune = xrealloc(prune, sizeof(*prune) * prune_num);
 859                         prune[prune_num-2] = ce->name;
 860                         prune[prune_num-1] = NULL;
 861                 }
 862                 while ((i+1 < active_nr) &&
 863                        ce_same_name(ce, active_cache[i+1]))
 864                         i++;
 865         }
 866         revs->prune_data = prune;
 867         revs->limited = 1;
 868 }
 869
 870 int handle_revision_arg(const char *arg, struct rev_info *revs,
 871                         int flags,
 872                         int cant_be_filename)
 873 {
 874         unsigned mode;
 875         char *dotdot;
 876         struct object *object;
 877         unsigned char sha1[20];
 878         int local_flags;
 879
 880         dotdot = strstr(arg, "..");
 881         if (dotdot) {
 882                 unsigned char from_sha1[20];
 883                 const char *next = dotdot + 2;
 884                 const char *this = arg;
 885                 int symmetric = *next == '.';
 886                 unsigned int flags_exclude = flags ^ UNINTERESTING;
 887
 888                 *dotdot = 0;
 889                 next += symmetric;
 890
 891                 if (!*next)
 892                         next = "HEAD";
 893                 if (dotdot == arg)
 894                         this = "HEAD";
 895                 if (!get_sha1(this, from_sha1) &&
 896                     !get_sha1(next, sha1)) {
 897                         struct commit *a, *b;
 898                         struct commit_list *exclude;
 899
 900                         a = lookup_commit_reference(from_sha1);
 901                         b = lookup_commit_reference(sha1);
 902                         if (!a || !b) {
 903                                 die(symmetric ?
 904                                     "Invalid symmetric difference expression %s...%s" :
 905                                     "Invalid revision range %s..%s",
 906                                     arg, next);
 907                         }
 908
 909                         if (!cant_be_filename) {
 910                                 *dotdot = '.';
 911                                 verify_non_filename(revs->prefix, arg);
 912                         }
 913
 914                         if (symmetric) {
 915                                 exclude = get_merge_bases(a, b, 1);
 916                                 add_pending_commit_list(revs, exclude,
 917                                                         flags_exclude);
 918                                 free_commit_list(exclude);
 919                                 a->object.flags |= flags | SYMMETRIC_LEFT;
 920                         } else
 921                                 a->object.flags |= flags_exclude;
 922                         b->object.flags |= flags;
 923                         add_pending_object(revs, &a->object, this);
 924                         add_pending_object(revs, &b->object, next);
 925                         return 0;
 926                 }
 927                 *dotdot = '.';
 928         }
 929         dotdot = strstr(arg, "^@");
 930         if (dotdot && !dotdot[2]) {
 931                 *dotdot = 0;
 932                 if (add_parents_only(revs, arg, flags))
 933                         return 0;
 934                 *dotdot = '^';
 935         }
 936         dotdot = strstr(arg, "^!");
 937         if (dotdot && !dotdot[2]) {
 938                 *dotdot = 0;
 939                 if (!add_parents_only(revs, arg, flags ^ UNINTERESTING))
 940                         *dotdot = '^';
 941         }
 942
 943         local_flags = 0;
 944         if (*arg == '^') {
 945                 local_flags = UNINTERESTING;
 946                 arg++;
 947         }
 948         if (get_sha1_with_mode(arg, sha1, &mode))
 949                 return -1;
 950         if (!cant_be_filename)
 951                 verify_non_filename(revs->prefix, arg);
 952         object = get_reference(revs, arg, sha1, flags ^ local_flags);
 953         add_pending_object_with_mode(revs, object, arg, mode);
 954         return 0;
 955 }
 956
 957 static void read_pathspec_from_stdin(struct rev_info *revs, struct strbuf *sb, const char ***prune_data)
 958 {
 959         const char **prune = *prune_data;
 960         int prune_nr;
 961         int prune_alloc;
 962
 963         /* count existing ones */
 964         if (!prune)
 965                 prune_nr = 0;
 966         else
 967                 for (prune_nr = 0; prune[prune_nr]; prune_nr++)
 968                         ;
 969         prune_alloc = prune_nr; /* not really, but we do not know */
 970
 971         while (strbuf_getwholeline(sb, stdin, '\n') != EOF) {
 972                 int len = sb->len;
 973                 if (len && sb->buf[len - 1] == '\n')
 974                         sb->buf[--len] = '\0';
 975                 ALLOC_GROW(prune, prune_nr+1, prune_alloc);
 976                 prune[prune_nr++] = xstrdup(sb->buf);
 977         }
 978         if (prune) {
 979                 ALLOC_GROW(prune, prune_nr+1, prune_alloc);
 980                 prune[prune_nr] = NULL;
 981         }
 982         *prune_data = prune;
 983 }
 984
 985 static void read_revisions_from_stdin(struct rev_info *revs, const char ***prune)
 986 {
 987         struct strbuf sb;
 988         int seen_dashdash = 0;
 989
 990         strbuf_init(&sb, 1000);
 991         while (strbuf_getwholeline(&sb, stdin, '\n') != EOF) {
 992                 int len = sb.len;
 993                 if (len && sb.buf[len - 1] == '\n')
 994                         sb.buf[--len] = '\0';
 995                 if (!len)
 996                         break;
 997                 if (sb.buf[0] == '-') {
 998                         if (len == 2 && sb.buf[1] == '-') {
 999                                 seen_dashdash = 1;
1000                                 break;
1001                         }
1002                         die("options not supported in --stdin mode");
1003                 }
1004                 if (handle_revision_arg(sb.buf, revs, 0, 1))
1005                         die("bad revision '%s'", sb.buf);
1006         }
1007         if (seen_dashdash)
1008                 read_pathspec_from_stdin(revs, &sb, prune);
1009         strbuf_release(&sb);
1010 }
1011
1012 static void add_grep(struct rev_info *revs, const char *ptn, enum grep_pat_token what)
1013 {
1014         append_grep_pattern(&revs->grep_filter, ptn, "command line", 0, what);
1015 }
1016
1017 static void add_header_grep(struct rev_info *revs, enum grep_header_field field, const char *pattern)
1018 {
1019         append_header_grep_pattern(&revs->grep_filter, field, pattern);
1020 }
1021
1022 static void add_message_grep(struct rev_info *revs, const char *pattern)
1023 {
1024         add_grep(revs, pattern, GREP_PATTERN_BODY);
1025 }
1026
1027 static int handle_revision_opt(struct rev_info *revs, int argc, const char **argv,
1028                                int *unkc, const char **unkv)
1029 {
1030         const char *arg = argv[0];
1031
1032         /* pseudo revision arguments */
1033         if (!strcmp(arg, "--all") || !strcmp(arg, "--branches") ||
1034             !strcmp(arg, "--tags") || !strcmp(arg, "--remotes") ||
1035             !strcmp(arg, "--reflog") || !strcmp(arg, "--not") ||
1036             !strcmp(arg, "--no-walk") || !strcmp(arg, "--do-walk") ||
1037             !strcmp(arg, "--bisect"))
1038         {
1039                 unkv[(*unkc)++] = arg;
1040                 return 1;
1041         }
1042
1043         if (!prefixcmp(arg, "--max-count=")) {
1044                 revs->max_count = atoi(arg + 12);
1045         } else if (!prefixcmp(arg, "--skip=")) {
1046                 revs->skip_count = atoi(arg + 7);
1047         } else if ((*arg == '-') && isdigit(arg[1])) {
1048         /* accept -<digit>, like traditional "head" */
1049                 revs->max_count = atoi(arg + 1);
1050         } else if (!strcmp(arg, "-n")) {
1051                 if (argc <= 1)
1052                         return error("-n requires an argument");
1053                 revs->max_count = atoi(argv[1]);
1054                 return 2;
1055         } else if (!prefixcmp(arg, "-n")) {
1056                 revs->max_count = atoi(arg + 2);
1057         } else if (!prefixcmp(arg, "--max-age=")) {
1058                 revs->max_age = atoi(arg + 10);
1059         } else if (!prefixcmp(arg, "--since=")) {
1060                 revs->max_age = approxidate(arg + 8);
1061         } else if (!prefixcmp(arg, "--after=")) {
1062                 revs->max_age = approxidate(arg + 8);
1063         } else if (!prefixcmp(arg, "--min-age=")) {
1064                 revs->min_age = atoi(arg + 10);
1065         } else if (!prefixcmp(arg, "--before=")) {
1066                 revs->min_age = approxidate(arg + 9);
1067         } else if (!prefixcmp(arg, "--until=")) {
1068                 revs->min_age = approxidate(arg + 8);
1069         } else if (!strcmp(arg, "--first-parent")) {
1070                 revs->first_parent_only = 1;
1071         } else if (!strcmp(arg, "-g") || !strcmp(arg, "--walk-reflogs")) {
1072                 init_reflog_walk(&revs->reflog_info);
1073         } else if (!strcmp(arg, "--default")) {
1074                 if (argc <= 1)
1075                         return error("bad --default argument");
1076                 revs->def = argv[1];
1077                 return 2;
1078         } else if (!strcmp(arg, "--merge")) {
1079                 revs->show_merge = 1;
1080         } else if (!strcmp(arg, "--topo-order")) {
1081                 revs->lifo = 1;
1082                 revs->topo_order = 1;
1083         } else if (!strcmp(arg, "--simplify-merges")) {
1084                 revs->simplify_merges = 1;
1085                 revs->rewrite_parents = 1;
1086                 revs->simplify_history = 0;
1087                 revs->limited = 1;
1088         } else if (!strcmp(arg, "--simplify-by-decoration")) {
1089                 revs->simplify_merges = 1;
1090                 revs->rewrite_parents = 1;
1091                 revs->simplify_history = 0;
1092                 revs->simplify_by_decoration = 1;
1093                 revs->limited = 1;
1094                 revs->prune = 1;
1095                 load_ref_decorations(DECORATE_SHORT_REFS);
1096         } else if (!strcmp(arg, "--date-order")) {
1097                 revs->lifo = 0;
1098                 revs->topo_order = 1;
1099         } else if (!prefixcmp(arg, "--early-output")) {
1100                 int count = 100;
1101                 switch (arg[14]) {
1102                 case '=':
1103                         count = atoi(arg+15);
1104                         /* Fallthrough */
1105                 case 0:
1106                         revs->topo_order = 1;
1107                        revs->early_output = count;
1108                 }
1109         } else if (!strcmp(arg, "--parents")) {
1110                 revs->rewrite_parents = 1;
1111                 revs->print_parents = 1;
1112         } else if (!strcmp(arg, "--dense")) {
1113                 revs->dense = 1;
1114         } else if (!strcmp(arg, "--sparse")) {
1115                 revs->dense = 0;
1116         } else if (!strcmp(arg, "--show-all")) {
1117                 revs->show_all = 1;
1118         } else if (!strcmp(arg, "--remove-empty")) {
1119                 revs->remove_empty_trees = 1;
1120         } else if (!strcmp(arg, "--merges")) {
1121                 revs->merges_only = 1;
1122         } else if (!strcmp(arg, "--no-merges")) {
1123                 revs->no_merges = 1;
1124         } else if (!strcmp(arg, "--boundary")) {
1125                 revs->boundary = 1;
1126         } else if (!strcmp(arg, "--left-right")) {
1127                 revs->left_right = 1;
1128         } else if (!strcmp(arg, "--cherry-pick")) {
1129                 revs->cherry_pick = 1;
1130                 revs->limited = 1;
1131         } else if (!strcmp(arg, "--objects")) {
1132                 revs->tag_objects = 1;
1133                 revs->tree_objects = 1;
1134                 revs->blob_objects = 1;
1135         } else if (!strcmp(arg, "--objects-edge")) {
1136                 revs->tag_objects = 1;
1137                 revs->tree_objects = 1;
1138                 revs->blob_objects = 1;
1139                 revs->edge_hint = 1;
1140         } else if (!strcmp(arg, "--unpacked")) {
1141                 revs->unpacked = 1;
1142         } else if (!prefixcmp(arg, "--unpacked=")) {
1143                 die("--unpacked=<packfile> no longer supported.");
1144         } else if (!strcmp(arg, "-r")) {
1145                 revs->diff = 1;
1146                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1147         } else if (!strcmp(arg, "-t")) {
1148                 revs->diff = 1;
1149                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1150                 DIFF_OPT_SET(&revs->diffopt, TREE_IN_RECURSIVE);
1151         } else if (!strcmp(arg, "-m")) {
1152                 revs->ignore_merges = 0;
1153         } else if (!strcmp(arg, "-c")) {
1154                 revs->diff = 1;
1155                 revs->dense_combined_merges = 0;
1156                 revs->combine_merges = 1;
1157         } else if (!strcmp(arg, "--cc")) {
1158                 revs->diff = 1;
1159                 revs->dense_combined_merges = 1;
1160                 revs->combine_merges = 1;
1161         } else if (!strcmp(arg, "-v")) {
1162                 revs->verbose_header = 1;
1163         } else if (!strcmp(arg, "--pretty")) {
1164                 revs->verbose_header = 1;
1165                 revs->pretty_given = 1;
1166                 get_commit_format(arg+8, revs);
1167         } else if (!prefixcmp(arg, "--pretty=") || !prefixcmp(arg, "--format=")) {
1168                 revs->verbose_header = 1;
1169                 revs->pretty_given = 1;
1170                 get_commit_format(arg+9, revs);
1171         } else if (!strcmp(arg, "--show-notes")) {
1172                 revs->show_notes = 1;
1173                 revs->show_notes_given = 1;
1174         } else if (!strcmp(arg, "--no-notes")) {
1175                 revs->show_notes = 0;
1176                 revs->show_notes_given = 1;
1177         } else if (!strcmp(arg, "--oneline")) {
1178                 revs->verbose_header = 1;
1179                 get_commit_format("oneline", revs);
1180                 revs->pretty_given = 1;
1181                 revs->abbrev_commit = 1;
1182         } else if (!strcmp(arg, "--graph")) {
1183                 revs->topo_order = 1;
1184                 revs->rewrite_parents = 1;
1185                 revs->graph = graph_init(revs);
1186         } else if (!strcmp(arg, "--root")) {
1187                 revs->show_root_diff = 1;
1188         } else if (!strcmp(arg, "--no-commit-id")) {
1189                 revs->no_commit_id = 1;
1190         } else if (!strcmp(arg, "--always")) {
1191                 revs->always_show_header = 1;
1192         } else if (!strcmp(arg, "--no-abbrev")) {
1193                 revs->abbrev = 0;
1194         } else if (!strcmp(arg, "--abbrev")) {
1195                 revs->abbrev = DEFAULT_ABBREV;
1196         } else if (!prefixcmp(arg, "--abbrev=")) {
1197                 revs->abbrev = strtoul(arg + 9, NULL, 10);
1198                 if (revs->abbrev < MINIMUM_ABBREV)
1199                         revs->abbrev = MINIMUM_ABBREV;
1200                 else if (revs->abbrev > 40)
1201                         revs->abbrev = 40;
1202         } else if (!strcmp(arg, "--abbrev-commit")) {
1203                 revs->abbrev_commit = 1;
1204         } else if (!strcmp(arg, "--full-diff")) {
1205                 revs->diff = 1;
1206                 revs->full_diff = 1;
1207         } else if (!strcmp(arg, "--full-history")) {
1208                 revs->simplify_history = 0;
1209         } else if (!strcmp(arg, "--relative-date")) {
1210                 revs->date_mode = DATE_RELATIVE;
1211                 revs->date_mode_explicit = 1;
1212         } else if (!strncmp(arg, "--date=", 7)) {
1213                 revs->date_mode = parse_date_format(arg + 7);
1214                 revs->date_mode_explicit = 1;
1215         } else if (!strcmp(arg, "--log-size")) {
1216                 revs->show_log_size = 1;
1217         }
1218         /*
1219          * Grepping the commit log
1220          */
1221         else if (!prefixcmp(arg, "--author=")) {
1222                 add_header_grep(revs, GREP_HEADER_AUTHOR, arg+9);
1223         } else if (!prefixcmp(arg, "--committer=")) {
1224                 add_header_grep(revs, GREP_HEADER_COMMITTER, arg+12);
1225         } else if (!prefixcmp(arg, "--grep=")) {
1226                 add_message_grep(revs, arg+7);
1227         } else if (!strcmp(arg, "--extended-regexp") || !strcmp(arg, "-E")) {
1228                 revs->grep_filter.regflags |= REG_EXTENDED;
1229         } else if (!strcmp(arg, "--regexp-ignore-case") || !strcmp(arg, "-i")) {
1230                 revs->grep_filter.regflags |= REG_ICASE;
1231         } else if (!strcmp(arg, "--fixed-strings") || !strcmp(arg, "-F")) {
1232                 revs->grep_filter.fixed = 1;
1233         } else if (!strcmp(arg, "--all-match")) {
1234                 revs->grep_filter.all_match = 1;
1235         } else if (!prefixcmp(arg, "--encoding=")) {
1236                 arg += 11;
1237                 if (strcmp(arg, "none"))
1238                         git_log_output_encoding = xstrdup(arg);
1239                 else
1240                         git_log_output_encoding = "";
1241         } else if (!strcmp(arg, "--reverse")) {
1242                 revs->reverse ^= 1;
1243         } else if (!strcmp(arg, "--children")) {
1244                 revs->children.name = "children";
1245                 revs->limited = 1;
1246         } else {
1247                 int opts = diff_opt_parse(&revs->diffopt, argv, argc);
1248                 if (!opts)
1249                         unkv[(*unkc)++] = arg;
1250                 return opts;
1251         }
1252
1253         return 1;
1254 }
1255
1256 void parse_revision_opt(struct rev_info *revs, struct parse_opt_ctx_t *ctx,
1257                         const struct option *options,
1258                         const char * const usagestr[])
1259 {
1260         int n = handle_revision_opt(revs, ctx->argc, ctx->argv,
1261                                     &ctx->cpidx, ctx->out);
1262         if (n <= 0) {
1263                 error("unknown option `%s'", ctx->argv[0]);
1264                 usage_with_options(usagestr, options);
1265         }
1266         ctx->argv += n;
1267         ctx->argc -= n;
1268 }
1269
1270 static int for_each_bad_bisect_ref(each_ref_fn fn, void *cb_data)
1271 {
1272         return for_each_ref_in("refs/bisect/bad", fn, cb_data);
1273 }
1274
1275 static int for_each_good_bisect_ref(each_ref_fn fn, void *cb_data)
1276 {
1277         return for_each_ref_in("refs/bisect/good", fn, cb_data);
1278 }
1279
1280 static void append_prune_data(const char ***prune_data, const char **av)
1281 {
1282         const char **prune = *prune_data;
1283         int prune_nr;
1284         int prune_alloc;
1285
1286         if (!prune) {
1287                 *prune_data = av;
1288                 return;
1289         }
1290
1291         /* count existing ones */
1292         for (prune_nr = 0; prune[prune_nr]; prune_nr++)
1293                 ;
1294         prune_alloc = prune_nr; /* not really, but we do not know */
1295
1296         while (*av) {
1297                 ALLOC_GROW(prune, prune_nr+1, prune_alloc);
1298                 prune[prune_nr++] = *av;
1299                 av++;
1300         }
1301         if (prune) {
1302                 ALLOC_GROW(prune, prune_nr+1, prune_alloc);
1303                 prune[prune_nr] = NULL;
1304         }
1305         *prune_data = prune;
1306 }
1307
1308 /*
1309  * Parse revision information, filling in the "rev_info" structure,
1310  * and removing the used arguments from the argument list.
1311  *
1312  * Returns the number of arguments left that weren't recognized
1313  * (which are also moved to the head of the argument list)
1314  */
1315 int setup_revisions(int argc, const char **argv, struct rev_info *revs, const char *def)
1316 {
1317         int i, flags, left, seen_dashdash, read_from_stdin;
1318         const char **prune_data = NULL;
1319
1320         /* First, search for "--" */
1321         seen_dashdash = 0;
1322         for (i = 1; i < argc; i++) {
1323                 const char *arg = argv[i];
1324                 if (strcmp(arg, "--"))
1325                         continue;
1326                 argv[i] = NULL;
1327                 argc = i;
1328                 if (argv[i + 1])
1329                         prune_data = argv + i + 1;
1330                 seen_dashdash = 1;
1331                 break;
1332         }
1333
1334         /* Second, deal with arguments and options */
1335         flags = 0;
1336         read_from_stdin = 0;
1337         for (left = i = 1; i < argc; i++) {
1338                 const char *arg = argv[i];
1339                 if (*arg == '-') {
1340                         int opts;
1341
1342                         if (!strcmp(arg, "--all")) {
1343                                 handle_refs(revs, flags, for_each_ref);
1344                                 handle_refs(revs, flags, head_ref);
1345                                 continue;
1346                         }
1347                         if (!strcmp(arg, "--branches")) {
1348                                 handle_refs(revs, flags, for_each_branch_ref);
1349                                 continue;
1350                         }
1351                         if (!strcmp(arg, "--bisect")) {
1352                                 handle_refs(revs, flags, for_each_bad_bisect_ref);
1353                                 handle_refs(revs, flags ^ UNINTERESTING, for_each_good_bisect_ref);
1354                                 revs->bisect = 1;
1355                                 continue;
1356                         }
1357                         if (!strcmp(arg, "--tags")) {
1358                                 handle_refs(revs, flags, for_each_tag_ref);
1359                                 continue;
1360                         }
1361                         if (!strcmp(arg, "--remotes")) {
1362                                 handle_refs(revs, flags, for_each_remote_ref);
1363                                 continue;
1364                         }
1365                         if (!strcmp(arg, "--reflog")) {
1366                                 handle_reflog(revs, flags);
1367                                 continue;
1368                         }
1369                         if (!strcmp(arg, "--not")) {
1370                                 flags ^= UNINTERESTING;
1371                                 continue;
1372                         }
1373                         if (!strcmp(arg, "--no-walk")) {
1374                                 revs->no_walk = 1;
1375                                 continue;
1376                         }
1377                         if (!strcmp(arg, "--do-walk")) {
1378                                 revs->no_walk = 0;
1379                                 continue;
1380                         }
1381                         if (!strcmp(arg, "--stdin")) {
1382                                 if (revs->disable_stdin) {
1383                                         argv[left++] = arg;
1384                                         continue;
1385                                 }
1386                                 if (read_from_stdin++)
1387                                         die("--stdin given twice?");
1388                                 read_revisions_from_stdin(revs, &prune_data);
1389                                 continue;
1390                         }
1391
1392                         opts = handle_revision_opt(revs, argc - i, argv + i, &left, argv);
1393                         if (opts > 0) {
1394                                 i += opts - 1;
1395                                 continue;
1396                         }
1397                         if (opts < 0)
1398                                 exit(128);
1399                         continue;
1400                 }
1401
1402                 if (handle_revision_arg(arg, revs, flags, seen_dashdash)) {
1403                         int j;
1404                         if (seen_dashdash || *arg == '^')
1405                                 die("bad revision '%s'", arg);
1406
1407                         /* If we didn't have a "--":
1408                          * (1) all filenames must exist;
1409                          * (2) all rev-args must not be interpretable
1410                          *     as a valid filename.
1411                          * but the latter we have checked in the main loop.
1412                          */
1413                         for (j = i; j < argc; j++)
1414                                 verify_filename(revs->prefix, argv[j]);
1415
1416                         append_prune_data(&prune_data, argv + i);
1417                         break;
1418                 }
1419         }
1420
1421         if (prune_data)
1422                 revs->prune_data = get_pathspec(revs->prefix, prune_data);
1423
1424         if (revs->def == NULL)
1425                 revs->def = def;
1426         if (revs->show_merge)
1427                 prepare_show_merge(revs);
1428         if (revs->def && !revs->pending.nr) {
1429                 unsigned char sha1[20];
1430                 struct object *object;
1431                 unsigned mode;
1432                 if (get_sha1_with_mode(revs->def, sha1, &mode))
1433                         die("bad default revision '%s'", revs->def);
1434                 object = get_reference(revs, revs->def, sha1, 0);
1435                 add_pending_object_with_mode(revs, object, revs->def, mode);
1436         }
1437
1438         /* Did the user ask for any diff output? Run the diff! */
1439         if (revs->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT)
1440                 revs->diff = 1;
1441
1442         /* Pickaxe, diff-filter and rename following need diffs */
1443         if (revs->diffopt.pickaxe ||
1444             revs->diffopt.filter ||
1445             DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1446                 revs->diff = 1;
1447
1448         if (revs->topo_order)
1449                 revs->limited = 1;
1450
1451         if (revs->prune_data) {
1452                 diff_tree_setup_paths(revs->prune_data, &revs->pruning);
1453                 /* Can't prune commits with rename following: the paths change.. */
1454                 if (!DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1455                         revs->prune = 1;
1456                 if (!revs->full_diff)
1457                         diff_tree_setup_paths(revs->prune_data, &revs->diffopt);
1458         }
1459         if (revs->combine_merges) {
1460                 revs->ignore_merges = 0;
1461                 if (revs->dense_combined_merges && !revs->diffopt.output_format)
1462                         revs->diffopt.output_format = DIFF_FORMAT_PATCH;
1463         }
1464         revs->diffopt.abbrev = revs->abbrev;
1465         if (diff_setup_done(&revs->diffopt) < 0)
1466                 die("diff_setup_done failed");
1467
1468         compile_grep_patterns(&revs->grep_filter);
1469
1470         if (revs->reverse && revs->reflog_info)
1471                 die("cannot combine --reverse with --walk-reflogs");
1472         if (revs->rewrite_parents && revs->children.name)
1473                 die("cannot combine --parents and --children");
1474
1475         /*
1476          * Limitations on the graph functionality
1477          */
1478         if (revs->reverse && revs->graph)
1479                 die("cannot combine --reverse with --graph");
1480
1481         if (revs->reflog_info && revs->graph)
1482                 die("cannot combine --walk-reflogs with --graph");
1483
1484         return left;
1485 }
1486
1487 static void add_child(struct rev_info *revs, struct commit *parent, struct commit *child)
1488 {
1489         struct commit_list *l = xcalloc(1, sizeof(*l));
1490
1491         l->item = child;
1492         l->next = add_decoration(&revs->children, &parent->object, l);
1493 }
1494
1495 static int remove_duplicate_parents(struct commit *commit)
1496 {
1497         struct commit_list **pp, *p;
1498         int surviving_parents;
1499
1500         /* Examine existing parents while marking ones we have seen... */
1501         pp = &commit->parents;
1502         while ((p = *pp) != NULL) {
1503                 struct commit *parent = p->item;
1504                 if (parent->object.flags & TMP_MARK) {
1505                         *pp = p->next;
1506                         continue;
1507                 }
1508                 parent->object.flags |= TMP_MARK;
1509                 pp = &p->next;
1510         }
1511         /* count them while clearing the temporary mark */
1512         surviving_parents = 0;
1513         for (p = commit->parents; p; p = p->next) {
1514                 p->item->object.flags &= ~TMP_MARK;
1515                 surviving_parents++;
1516         }
1517         return surviving_parents;
1518 }
1519
1520 struct merge_simplify_state {
1521         struct commit *simplified;
1522 };
1523
1524 static struct merge_simplify_state *locate_simplify_state(struct rev_info *revs, struct commit *commit)
1525 {
1526         struct merge_simplify_state *st;
1527
1528         st = lookup_decoration(&revs->merge_simplification, &commit->object);
1529         if (!st) {
1530                 st = xcalloc(1, sizeof(*st));
1531                 add_decoration(&revs->merge_simplification, &commit->object, st);
1532         }
1533         return st;
1534 }
1535
1536 static struct commit_list **simplify_one(struct rev_info *revs, struct commit *commit, struct commit_list **tail)
1537 {
1538         struct commit_list *p;
1539         struct merge_simplify_state *st, *pst;
1540         int cnt;
1541
1542         st = locate_simplify_state(revs, commit);
1543
1544         /*
1545          * Have we handled this one?
1546          */
1547         if (st->simplified)
1548                 return tail;
1549
1550         /*
1551          * An UNINTERESTING commit simplifies to itself, so does a
1552          * root commit.  We do not rewrite parents of such commit
1553          * anyway.
1554          */
1555         if ((commit->object.flags & UNINTERESTING) || !commit->parents) {
1556                 st->simplified = commit;
1557                 return tail;
1558         }
1559
1560         /*
1561          * Do we know what commit all of our parents should be rewritten to?
1562          * Otherwise we are not ready to rewrite this one yet.
1563          */
1564         for (cnt = 0, p = commit->parents; p; p = p->next) {
1565                 pst = locate_simplify_state(revs, p->item);
1566                 if (!pst->simplified) {
1567                         tail = &commit_list_insert(p->item, tail)->next;
1568                         cnt++;
1569                 }
1570         }
1571         if (cnt) {
1572                 tail = &commit_list_insert(commit, tail)->next;
1573                 return tail;
1574         }
1575
1576         /*
1577          * Rewrite our list of parents.
1578          */
1579         for (p = commit->parents; p; p = p->next) {
1580                 pst = locate_simplify_state(revs, p->item);
1581                 p->item = pst->simplified;
1582         }
1583         cnt = remove_duplicate_parents(commit);
1584
1585         /*
1586          * It is possible that we are a merge and one side branch
1587          * does not have any commit that touches the given paths;
1588          * in such a case, the immediate parents will be rewritten
1589          * to different commits.
1590          *
1591          *      o----X          X: the commit we are looking at;
1592          *     /    /           o: a commit that touches the paths;
1593          * ---o----'
1594          *
1595          * Further reduce the parents by removing redundant parents.
1596          */
1597         if (1 < cnt) {
1598                 struct commit_list *h = reduce_heads(commit->parents);
1599                 cnt = commit_list_count(h);
1600                 free_commit_list(commit->parents);
1601                 commit->parents = h;
1602         }
1603
1604         /*
1605          * A commit simplifies to itself if it is a root, if it is
1606          * UNINTERESTING, if it touches the given paths, or if it is a
1607          * merge and its parents simplifies to more than one commits
1608          * (the first two cases are already handled at the beginning of
1609          * this function).
1610          *
1611          * Otherwise, it simplifies to what its sole parent simplifies to.
1612          */
1613         if (!cnt ||
1614             (commit->object.flags & UNINTERESTING) ||
1615             !(commit->object.flags & TREESAME) ||
1616             (1 < cnt))
1617                 st->simplified = commit;
1618         else {
1619                 pst = locate_simplify_state(revs, commit->parents->item);
1620                 st->simplified = pst->simplified;
1621         }
1622         return tail;
1623 }
1624
1625 static void simplify_merges(struct rev_info *revs)
1626 {
1627         struct commit_list *list;
1628         struct commit_list *yet_to_do, **tail;
1629
1630         if (!revs->topo_order)
1631                 sort_in_topological_order(&revs->commits, revs->lifo);
1632         if (!revs->prune)
1633                 return;
1634
1635         /* feed the list reversed */
1636         yet_to_do = NULL;
1637         for (list = revs->commits; list; list = list->next)
1638                 commit_list_insert(list->item, &yet_to_do);
1639         while (yet_to_do) {
1640                 list = yet_to_do;
1641                 yet_to_do = NULL;
1642                 tail = &yet_to_do;
1643                 while (list) {
1644                         struct commit *commit = list->item;
1645                         struct commit_list *next = list->next;
1646                         free(list);
1647                         list = next;
1648                         tail = simplify_one(revs, commit, tail);
1649                 }
1650         }
1651
1652         /* clean up the result, removing the simplified ones */
1653         list = revs->commits;
1654         revs->commits = NULL;
1655         tail = &revs->commits;
1656         while (list) {
1657                 struct commit *commit = list->item;
1658                 struct commit_list *next = list->next;
1659                 struct merge_simplify_state *st;
1660                 free(list);
1661                 list = next;
1662                 st = locate_simplify_state(revs, commit);
1663                 if (st->simplified == commit)
1664                         tail = &commit_list_insert(commit, tail)->next;
1665         }
1666 }
1667
1668 static void set_children(struct rev_info *revs)
1669 {
1670         struct commit_list *l;
1671         for (l = revs->commits; l; l = l->next) {
1672                 struct commit *commit = l->item;
1673                 struct commit_list *p;
1674
1675                 for (p = commit->parents; p; p = p->next)
1676                         add_child(revs, p->item, commit);
1677         }
1678 }
1679
1680 int prepare_revision_walk(struct rev_info *revs)
1681 {
1682         int nr = revs->pending.nr;
1683         struct object_array_entry *e, *list;
1684
1685         e = list = revs->pending.objects;
1686         revs->pending.nr = 0;
1687         revs->pending.alloc = 0;
1688         revs->pending.objects = NULL;
1689         while (--nr >= 0) {
1690                 struct commit *commit = handle_commit(revs, e->item, e->name);
1691                 if (commit) {
1692                         if (!(commit->object.flags & SEEN)) {
1693                                 commit->object.flags |= SEEN;
1694                                 insert_by_date(commit, &revs->commits);
1695                         }
1696                 }
1697                 e++;
1698         }
1699         free(list);
1700
1701         if (revs->no_walk)
1702                 return 0;
1703         if (revs->limited)
1704                 if (limit_list(revs) < 0)
1705                         return -1;
1706         if (revs->topo_order)
1707                 sort_in_topological_order(&revs->commits, revs->lifo);
1708         if (revs->simplify_merges)
1709                 simplify_merges(revs);
1710         if (revs->children.name)
1711                 set_children(revs);
1712         return 0;
1713 }
1714
1715 enum rewrite_result {
1716         rewrite_one_ok,
1717         rewrite_one_noparents,
1718         rewrite_one_error,
1719 };
1720
1721 static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp)
1722 {
1723         struct commit_list *cache = NULL;
1724
1725         for (;;) {
1726                 struct commit *p = *pp;
1727                 if (!revs->limited)
1728                         if (add_parents_to_list(revs, p, &revs->commits, &cache) < 0)
1729                                 return rewrite_one_error;
1730                 if (p->parents && p->parents->next)
1731                         return rewrite_one_ok;
1732                 if (p->object.flags & UNINTERESTING)
1733                         return rewrite_one_ok;
1734                 if (!(p->object.flags & TREESAME))
1735                         return rewrite_one_ok;
1736                 if (!p->parents)
1737                         return rewrite_one_noparents;
1738                 *pp = p->parents->item;
1739         }
1740 }
1741
1742 static int rewrite_parents(struct rev_info *revs, struct commit *commit)
1743 {
1744         struct commit_list **pp = &commit->parents;
1745         while (*pp) {
1746                 struct commit_list *parent = *pp;
1747                 switch (rewrite_one(revs, &parent->item)) {
1748                 case rewrite_one_ok:
1749                         break;
1750                 case rewrite_one_noparents:
1751                         *pp = parent->next;
1752                         continue;
1753                 case rewrite_one_error:
1754                         return -1;
1755                 }
1756                 pp = &parent->next;
1757         }
1758         remove_duplicate_parents(commit);
1759         return 0;
1760 }
1761
1762 static int commit_match(struct commit *commit, struct rev_info *opt)
1763 {
1764         if (!opt->grep_filter.pattern_list)
1765                 return 1;
1766         return grep_buffer(&opt->grep_filter,
1767                            NULL, /* we say nothing, not even filename */
1768                            commit->buffer, strlen(commit->buffer));
1769 }
1770
1771 static inline int want_ancestry(struct rev_info *revs)
1772 {
1773         return (revs->rewrite_parents || revs->children.name);
1774 }
1775
1776 enum commit_action get_commit_action(struct rev_info *revs, struct commit *commit)
1777 {
1778         if (commit->object.flags & SHOWN)
1779                 return commit_ignore;
1780         if (revs->unpacked && has_sha1_pack(commit->object.sha1))
1781                 return commit_ignore;
1782         if (revs->show_all)
1783                 return commit_show;
1784         if (commit->object.flags & UNINTERESTING)
1785                 return commit_ignore;
1786         if (revs->min_age != -1 && (commit->date > revs->min_age))
1787                 return commit_ignore;
1788         if (revs->no_merges && commit->parents && commit->parents->next)
1789                 return commit_ignore;
1790         if (revs->merges_only && !(commit->parents && commit->parents->next))
1791                 return commit_ignore;
1792         if (!commit_match(commit, revs))
1793                 return commit_ignore;
1794         if (revs->prune && revs->dense) {
1795                 /* Commit without changes? */
1796                 if (commit->object.flags & TREESAME) {
1797                         /* drop merges unless we want parenthood */
1798                         if (!want_ancestry(revs))
1799                                 return commit_ignore;
1800                         /* non-merge - always ignore it */
1801                         if (!commit->parents || !commit->parents->next)
1802                                 return commit_ignore;
1803                 }
1804         }
1805         return commit_show;
1806 }
1807
1808 enum commit_action simplify_commit(struct rev_info *revs, struct commit *commit)
1809 {
1810         enum commit_action action = get_commit_action(revs, commit);
1811
1812         if (action == commit_show &&
1813             !revs->show_all &&
1814             revs->prune && revs->dense && want_ancestry(revs)) {
1815                 if (rewrite_parents(revs, commit) < 0)
1816                         return commit_error;
1817         }
1818         return action;
1819 }
1820
1821 static struct commit *get_revision_1(struct rev_info *revs)
1822 {
1823         if (!revs->commits)
1824                 return NULL;
1825
1826         do {
1827                 struct commit_list *entry = revs->commits;
1828                 struct commit *commit = entry->item;
1829
1830                 revs->commits = entry->next;
1831                 free(entry);
1832
1833                 if (revs->reflog_info)
1834                         fake_reflog_parent(revs->reflog_info, commit);
1835
1836                 /*
1837                  * If we haven't done the list limiting, we need to look at
1838                  * the parents here. We also need to do the date-based limiting
1839                  * that we'd otherwise have done in limit_list().
1840                  */
1841                 if (!revs->limited) {
1842                         if (revs->max_age != -1 &&
1843                             (commit->date < revs->max_age))
1844                                 continue;
1845                         if (add_parents_to_list(revs, commit, &revs->commits, NULL) < 0)
1846                                 die("Failed to traverse parents of commit %s",
1847                                     sha1_to_hex(commit->object.sha1));
1848                 }
1849
1850                 switch (simplify_commit(revs, commit)) {
1851                 case commit_ignore:
1852                         continue;
1853                 case commit_error:
1854                         die("Failed to simplify parents of commit %s",
1855                             sha1_to_hex(commit->object.sha1));
1856                 default:
1857                         return commit;
1858                 }
1859         } while (revs->commits);
1860         return NULL;
1861 }
1862
1863 static void gc_boundary(struct object_array *array)
1864 {
1865         unsigned nr = array->nr;
1866         unsigned alloc = array->alloc;
1867         struct object_array_entry *objects = array->objects;
1868
1869         if (alloc <= nr) {
1870                 unsigned i, j;
1871                 for (i = j = 0; i < nr; i++) {
1872                         if (objects[i].item->flags & SHOWN)
1873                                 continue;
1874                         if (i != j)
1875                                 objects[j] = objects[i];
1876                         j++;
1877                 }
1878                 for (i = j; i < nr; i++)
1879                         objects[i].item = NULL;
1880                 array->nr = j;
1881         }
1882 }
1883
1884 static void create_boundary_commit_list(struct rev_info *revs)
1885 {
1886         unsigned i;
1887         struct commit *c;
1888         struct object_array *array = &revs->boundary_commits;
1889         struct object_array_entry *objects = array->objects;
1890
1891         /*
1892          * If revs->commits is non-NULL at this point, an error occurred in
1893          * get_revision_1().  Ignore the error and continue printing the
1894          * boundary commits anyway.  (This is what the code has always
1895          * done.)
1896          */
1897         if (revs->commits) {
1898                 free_commit_list(revs->commits);
1899                 revs->commits = NULL;
1900         }
1901
1902         /*
1903          * Put all of the actual boundary commits from revs->boundary_commits
1904          * into revs->commits
1905          */
1906         for (i = 0; i < array->nr; i++) {
1907                 c = (struct commit *)(objects[i].item);
1908                 if (!c)
1909                         continue;
1910                 if (!(c->object.flags & CHILD_SHOWN))
1911                         continue;
1912                 if (c->object.flags & (SHOWN | BOUNDARY))
1913                         continue;
1914                 c->object.flags |= BOUNDARY;
1915                 commit_list_insert(c, &revs->commits);
1916         }
1917
1918         /*
1919          * If revs->topo_order is set, sort the boundary commits
1920          * in topological order
1921          */
1922         sort_in_topological_order(&revs->commits, revs->lifo);
1923 }
1924
1925 static struct commit *get_revision_internal(struct rev_info *revs)
1926 {
1927         struct commit *c = NULL;
1928         struct commit_list *l;
1929
1930         if (revs->boundary == 2) {
1931                 /*
1932                  * All of the normal commits have already been returned,
1933                  * and we are now returning boundary commits.
1934                  * create_boundary_commit_list() has populated
1935                  * revs->commits with the remaining commits to return.
1936                  */
1937                 c = pop_commit(&revs->commits);
1938                 if (c)
1939                         c->object.flags |= SHOWN;
1940                 return c;
1941         }
1942
1943         /*
1944          * Now pick up what they want to give us
1945          */
1946         c = get_revision_1(revs);
1947         if (c) {
1948                 while (0 < revs->skip_count) {
1949                         revs->skip_count--;
1950                         c = get_revision_1(revs);
1951                         if (!c)
1952                                 break;
1953                 }
1954         }
1955
1956         /*
1957          * Check the max_count.
1958          */
1959         switch (revs->max_count) {
1960         case -1:
1961                 break;
1962         case 0:
1963                 c = NULL;
1964                 break;
1965         default:
1966                 revs->max_count--;
1967         }
1968
1969         if (c)
1970                 c->object.flags |= SHOWN;
1971
1972         if (!revs->boundary) {
1973                 return c;
1974         }
1975
1976         if (!c) {
1977                 /*
1978                  * get_revision_1() runs out the commits, and
1979                  * we are done computing the boundaries.
1980                  * switch to boundary commits output mode.
1981                  */
1982                 revs->boundary = 2;
1983
1984                 /*
1985                  * Update revs->commits to contain the list of
1986                  * boundary commits.
1987                  */
1988                 create_boundary_commit_list(revs);
1989
1990                 return get_revision_internal(revs);
1991         }
1992
1993         /*
1994          * boundary commits are the commits that are parents of the
1995          * ones we got from get_revision_1() but they themselves are
1996          * not returned from get_revision_1().  Before returning
1997          * 'c', we need to mark its parents that they could be boundaries.
1998          */
1999
2000         for (l = c->parents; l; l = l->next) {
2001                 struct object *p;
2002                 p = &(l->item->object);
2003                 if (p->flags & (CHILD_SHOWN | SHOWN))
2004                         continue;
2005                 p->flags |= CHILD_SHOWN;
2006                 gc_boundary(&revs->boundary_commits);
2007                 add_object_array(p, NULL, &revs->boundary_commits);
2008         }
2009
2010         return c;
2011 }
2012
2013 struct commit *get_revision(struct rev_info *revs)
2014 {
2015         struct commit *c;
2016         struct commit_list *reversed;
2017
2018         if (revs->reverse) {
2019                 reversed = NULL;
2020                 while ((c = get_revision_internal(revs))) {
2021                         commit_list_insert(c, &reversed);
2022                 }
2023                 revs->commits = reversed;
2024                 revs->reverse = 0;
2025                 revs->reverse_output_stage = 1;
2026         }
2027
2028         if (revs->reverse_output_stage)
2029                 return pop_commit(&revs->commits);
2030
2031         c = get_revision_internal(revs);
2032         if (c && revs->graph)
2033                 graph_update(revs->graph, c);
2034         return c;
2035 }