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 #include "rev-cache.h"
  16
  17 volatile show_early_output_fn_t show_early_output;
  18
  19 char *path_name(const struct name_path *path, const char *name)
  20 {
  21         const struct name_path *p;
  22         char *n, *m;
  23         int nlen = strlen(name);
  24         int len = nlen + 1;
  25
  26         for (p = path; p; p = p->up) {
  27                 if (p->elem_len)
  28                         len += p->elem_len + 1;
  29         }
  30         n = xmalloc(len);
  31         m = n + len - (nlen + 1);
  32         strcpy(m, name);
  33         for (p = path; p; p = p->up) {
  34                 if (p->elem_len) {
  35                         m -= p->elem_len + 1;
  36                         memcpy(m, p->elem, p->elem_len);
  37                         m[p->elem_len] = '/';
  38                 }
  39         }
  40         return n;
  41 }
  42
  43 void add_object(struct object *obj,
  44                 struct object_array *p,
  45                 struct name_path *path,
  46                 const char *name)
  47 {
  48         add_object_array(obj, path_name(path, name), p);
  49 }
  50
  51 static void mark_blob_uninteresting(struct blob *blob)
  52 {
  53         if (!blob)
  54                 return;
  55         if (blob->object.flags & UNINTERESTING)
  56                 return;
  57         blob->object.flags |= UNINTERESTING;
  58 }
  59
  60 void mark_tree_uninteresting(struct tree *tree)
  61 {
  62         struct tree_desc desc;
  63         struct name_entry entry;
  64         struct object *obj = &tree->object;
  65
  66         if (!tree)
  67                 return;
  68         if (obj->flags & UNINTERESTING)
  69                 return;
  70         obj->flags |= UNINTERESTING;
  71         if (!has_sha1_file(obj->sha1))
  72                 return;
  73         if (parse_tree(tree) < 0)
  74                 die("bad tree %s", sha1_to_hex(obj->sha1));
  75
  76         init_tree_desc(&desc, tree->buffer, tree->size);
  77         while (tree_entry(&desc, &entry)) {
  78                 switch (object_type(entry.mode)) {
  79                 case OBJ_TREE:
  80                         mark_tree_uninteresting(lookup_tree(entry.sha1));
  81                         break;
  82                 case OBJ_BLOB:
  83                         mark_blob_uninteresting(lookup_blob(entry.sha1));
  84                         break;
  85                 default:
  86                         /* Subproject commit - not in this repository */
  87                         break;
  88                 }
  89         }
  90
  91         /*
  92          * We don't care about the tree any more
  93          * after it has been marked uninteresting.
  94          */
  95         free(tree->buffer);
  96         tree->buffer = NULL;
  97 }
  98
  99 void mark_parents_uninteresting(struct commit *commit)
 100 {
 101         struct commit_list *parents = commit->parents;
 102
 103         while (parents) {
 104                 struct commit *commit = parents->item;
 105                 if (!(commit->object.flags & UNINTERESTING)) {
 106                         commit->object.flags |= UNINTERESTING;
 107
 108                         /*
 109                          * Normally we haven't parsed the parent
 110                          * yet, so we won't have a parent of a parent
 111                          * here. However, it may turn out that we've
 112                          * reached this commit some other way (where it
 113                          * wasn't uninteresting), in which case we need
 114                          * to mark its parents recursively too..
 115                          */
 116                         if (commit->parents)
 117                                 mark_parents_uninteresting(commit);
 118                 }
 119
 120                 /*
 121                  * A missing commit is ok iff its parent is marked
 122                  * uninteresting.
 123                  *
 124                  * We just mark such a thing parsed, so that when
 125                  * it is popped next time around, we won't be trying
 126                  * to parse it and get an error.
 127                  */
 128                 if (!has_sha1_file(commit->object.sha1))
 129                         commit->object.parsed = 1;
 130                 parents = parents->next;
 131         }
 132 }
 133
 134 static void add_pending_object_with_mode(struct rev_info *revs, struct object *obj, const char *name, unsigned mode)
 135 {
 136         if (revs->no_walk && (obj->flags & UNINTERESTING))
 137                 revs->no_walk = 0;
 138         if (revs->reflog_info && obj->type == OBJ_COMMIT &&
 139                         add_reflog_for_walk(revs->reflog_info,
 140                                 (struct commit *)obj, name))
 141                 return;
 142         add_object_array_with_mode(obj, name, &revs->pending, mode);
 143 }
 144
 145 void add_pending_object(struct rev_info *revs, struct object *obj, const char *name)
 146 {
 147         add_pending_object_with_mode(revs, obj, name, S_IFINVALID);
 148 }
 149
 150 void add_head_to_pending(struct rev_info *revs)
 151 {
 152         unsigned char sha1[20];
 153         struct object *obj;
 154         if (get_sha1("HEAD", sha1))
 155                 return;
 156         obj = parse_object(sha1);
 157         if (!obj)
 158                 return;
 159         add_pending_object(revs, obj, "HEAD");
 160 }
 161
 162 static struct object *get_reference(struct rev_info *revs, const char *name, const unsigned char *sha1, unsigned int flags)
 163 {
 164         struct object *object;
 165
 166         object = parse_object(sha1);
 167         if (!object)
 168                 die("bad object %s", name);
 169         object->flags |= flags;
 170         return object;
 171 }
 172
 173 static struct commit *handle_commit(struct rev_info *revs, struct object *object, const char *name)
 174 {
 175         unsigned long flags = object->flags;
 176
 177         /*
 178          * Tag object? Look what it points to..
 179          */
 180         while (object->type == OBJ_TAG) {
 181                 struct tag *tag = (struct tag *) object;
 182                 if (revs->tag_objects && !(flags & UNINTERESTING))
 183                         add_pending_object(revs, object, tag->tag);
 184                 if (!tag->tagged)
 185                         die("bad tag");
 186                 object = parse_object(tag->tagged->sha1);
 187                 if (!object) {
 188                         if (flags & UNINTERESTING)
 189                                 return NULL;
 190                         die("bad object %s", sha1_to_hex(tag->tagged->sha1));
 191                 }
 192         }
 193
 194         /*
 195          * Commit object? Just return it, we'll do all the complex
 196          * reachability crud.
 197          */
 198         if (object->type == OBJ_COMMIT) {
 199                 struct commit *commit = (struct commit *)object;
 200                 if (parse_commit(commit) < 0)
 201                         die("unable to parse commit %s", name);
 202                 if (flags & UNINTERESTING) {
 203                         commit->object.flags |= UNINTERESTING;
 204                         mark_parents_uninteresting(commit);
 205                         revs->limited = 1;
 206                 }
 207                 if (revs->show_source && !commit->util)
 208                         commit->util = (void *) name;
 209                 return commit;
 210         }
 211
 212         /*
 213          * Tree object? Either mark it uninteresting, or add it
 214          * to the list of objects to look at later..
 215          */
 216         if (object->type == OBJ_TREE) {
 217                 struct tree *tree = (struct tree *)object;
 218                 if (!revs->tree_objects)
 219                         return NULL;
 220                 if (flags & UNINTERESTING) {
 221                         mark_tree_uninteresting(tree);
 222                         return NULL;
 223                 }
 224                 add_pending_object(revs, object, "");
 225                 return NULL;
 226         }
 227
 228         /*
 229          * Blob object? You know the drill by now..
 230          */
 231         if (object->type == OBJ_BLOB) {
 232                 struct blob *blob = (struct blob *)object;
 233                 if (!revs->blob_objects)
 234                         return NULL;
 235                 if (flags & UNINTERESTING) {
 236                         mark_blob_uninteresting(blob);
 237                         return NULL;
 238                 }
 239                 add_pending_object(revs, object, "");
 240                 return NULL;
 241         }
 242         die("%s is unknown object", name);
 243 }
 244
 245 static int everybody_uninteresting(struct commit_list *orig)
 246 {
 247         struct commit_list *list = orig;
 248         while (list) {
 249                 struct commit *commit = list->item;
 250                 list = list->next;
 251                 if (commit->object.flags & UNINTERESTING)
 252                         continue;
 253                 return 0;
 254         }
 255         return 1;
 256 }
 257
 258 /*
 259  * The goal is to get REV_TREE_NEW as the result only if the
 260  * diff consists of all '+' (and no other changes), REV_TREE_OLD
 261  * if the whole diff is removal of old data, and otherwise
 262  * REV_TREE_DIFFERENT (of course if the trees are the same we
 263  * want REV_TREE_SAME).
 264  * That means that once we get to REV_TREE_DIFFERENT, we do not
 265  * have to look any further.
 266  */
 267 static int tree_difference = REV_TREE_SAME;
 268
 269 static void file_add_remove(struct diff_options *options,
 270                     int addremove, unsigned mode,
 271                     const unsigned char *sha1,
 272                     const char *fullpath)
 273 {
 274         int diff = addremove == '+' ? REV_TREE_NEW : REV_TREE_OLD;
 275
 276         tree_difference |= diff;
 277         if (tree_difference == REV_TREE_DIFFERENT)
 278                 DIFF_OPT_SET(options, HAS_CHANGES);
 279 }
 280
 281 static void file_change(struct diff_options *options,
 282                  unsigned old_mode, unsigned new_mode,
 283                  const unsigned char *old_sha1,
 284                  const unsigned char *new_sha1,
 285                  const char *fullpath)
 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 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         unsigned char *cache_sha1;
 643         char used_cache;
 644
 645         while (list) {
 646                 struct commit_list *entry = list;
 647                 struct commit *commit = list->item;
 648                 struct object *obj = &commit->object;
 649                 show_early_output_fn_t show;
 650
 651                 list = list->next;
 652                 free(entry);
 653
 654                 if (revs->max_age != -1 && (commit->date < revs->max_age))
 655                         obj->flags |= UNINTERESTING;
 656
 657                 /* rev-cache to the rescue!!! */
 658                 used_cache = 0;
 659                 if (!revs->dont_cache_me && !(obj->flags & ADDED)) {
 660                         cache_sha1 = get_cache_slice(commit);
 661                         if (cache_sha1) {
 662                                 if (traverse_cache_slice(revs, cache_sha1, commit, &date, &slop, &p, &list) < 0)
 663                                         used_cache = 0;
 664                                 else
 665                                         used_cache = 1;
 666                         }
 667                 }
 668
 669                 if (!used_cache) {
 670                         if (add_parents_to_list(revs, commit, &list, NULL) < 0)
 671                                 return -1;
 672                         if (obj->flags & UNINTERESTING) {
 673                                 mark_parents_uninteresting(commit); /* ME: why? */
 674                                 if (revs->show_all)
 675                                         p = &commit_list_insert(commit, p)->next;
 676                                 slop = still_interesting(list, date, slop);
 677                                 if (slop > 0)
 678                                         continue;
 679                                 /* If showing all, add the whole pending list to the end */
 680                                 if (revs->show_all)
 681                                         *p = list;
 682                                 break;
 683                         }
 684                         if (revs->min_age != -1 && (commit->date > revs->min_age))
 685                                 continue;
 686                         date = commit->date;
 687                         p = &commit_list_insert(commit, p)->next;
 688                 }
 689
 690                 show = show_early_output;
 691                 if (!show)
 692                         continue;
 693
 694                 show(revs, newlist);
 695                 show_early_output = NULL;
 696         }
 697         if (revs->cherry_pick)
 698                 cherry_pick_list(newlist, revs);
 699
 700         revs->commits = newlist;
 701         return 0;
 702 }
 703
 704 struct all_refs_cb {
 705         int all_flags;
 706         int warned_bad_reflog;
 707         struct rev_info *all_revs;
 708         const char *name_for_errormsg;
 709 };
 710
 711 static int handle_one_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
 712 {
 713         struct all_refs_cb *cb = cb_data;
 714         struct object *object = get_reference(cb->all_revs, path, sha1,
 715                                               cb->all_flags);
 716         add_pending_object(cb->all_revs, object, path);
 717         return 0;
 718 }
 719
 720 static void handle_refs(struct rev_info *revs, unsigned flags,
 721                 int (*for_each)(each_ref_fn, void *))
 722 {
 723         struct all_refs_cb cb;
 724         cb.all_revs = revs;
 725         cb.all_flags = flags;
 726         for_each(handle_one_ref, &cb);
 727 }
 728
 729 static void handle_one_reflog_commit(unsigned char *sha1, void *cb_data)
 730 {
 731         struct all_refs_cb *cb = cb_data;
 732         if (!is_null_sha1(sha1)) {
 733                 struct object *o = parse_object(sha1);
 734                 if (o) {
 735                         o->flags |= cb->all_flags;
 736                         add_pending_object(cb->all_revs, o, "");
 737                 }
 738                 else if (!cb->warned_bad_reflog) {
 739                         warning("reflog of '%s' references pruned commits",
 740                                 cb->name_for_errormsg);
 741                         cb->warned_bad_reflog = 1;
 742                 }
 743         }
 744 }
 745
 746 static int handle_one_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
 747                 const char *email, unsigned long timestamp, int tz,
 748                 const char *message, void *cb_data)
 749 {
 750         handle_one_reflog_commit(osha1, cb_data);
 751         handle_one_reflog_commit(nsha1, cb_data);
 752         return 0;
 753 }
 754
 755 static int handle_one_reflog(const char *path, const unsigned char *sha1, int flag, void *cb_data)
 756 {
 757         struct all_refs_cb *cb = cb_data;
 758         cb->warned_bad_reflog = 0;
 759         cb->name_for_errormsg = path;
 760         for_each_reflog_ent(path, handle_one_reflog_ent, cb_data);
 761         return 0;
 762 }
 763
 764 static void handle_reflog(struct rev_info *revs, unsigned flags)
 765 {
 766         struct all_refs_cb cb;
 767         cb.all_revs = revs;
 768         cb.all_flags = flags;
 769         for_each_reflog(handle_one_reflog, &cb);
 770 }
 771
 772 static int add_parents_only(struct rev_info *revs, const char *arg, int flags)
 773 {
 774         unsigned char sha1[20];
 775         struct object *it;
 776         struct commit *commit;
 777         struct commit_list *parents;
 778
 779         if (*arg == '^') {
 780                 flags ^= UNINTERESTING;
 781                 arg++;
 782         }
 783         if (get_sha1(arg, sha1))
 784                 return 0;
 785         while (1) {
 786                 it = get_reference(revs, arg, sha1, 0);
 787                 if (it->type != OBJ_TAG)
 788                         break;
 789                 if (!((struct tag*)it)->tagged)
 790                         return 0;
 791                 hashcpy(sha1, ((struct tag*)it)->tagged->sha1);
 792         }
 793         if (it->type != OBJ_COMMIT)
 794                 return 0;
 795         commit = (struct commit *)it;
 796         for (parents = commit->parents; parents; parents = parents->next) {
 797                 it = &parents->item->object;
 798                 it->flags |= flags;
 799                 add_pending_object(revs, it, arg);
 800         }
 801         return 1;
 802 }
 803
 804 void init_revisions(struct rev_info *revs, const char *prefix)
 805 {
 806         memset(revs, 0, sizeof(*revs));
 807
 808         revs->abbrev = DEFAULT_ABBREV;
 809         revs->ignore_merges = 1;
 810         revs->simplify_history = 1;
 811         DIFF_OPT_SET(&revs->pruning, RECURSIVE);
 812         DIFF_OPT_SET(&revs->pruning, QUIET);
 813         revs->pruning.add_remove = file_add_remove;
 814         revs->pruning.change = file_change;
 815         revs->lifo = 1;
 816         revs->dense = 1;
 817         revs->prefix = prefix;
 818         revs->max_age = -1;
 819         revs->min_age = -1;
 820         revs->skip_count = -1;
 821         revs->max_count = -1;
 822
 823         revs->commit_format = CMIT_FMT_DEFAULT;
 824
 825         revs->grep_filter.status_only = 1;
 826         revs->grep_filter.pattern_tail = &(revs->grep_filter.pattern_list);
 827         revs->grep_filter.regflags = REG_NEWLINE;
 828
 829         diff_setup(&revs->diffopt);
 830         if (prefix && !revs->diffopt.prefix) {
 831                 revs->diffopt.prefix = prefix;
 832                 revs->diffopt.prefix_length = strlen(prefix);
 833         }
 834
 835         init_rev_cache_info(&revs->rev_cache_info);
 836 }
 837
 838 static void add_pending_commit_list(struct rev_info *revs,
 839                                     struct commit_list *commit_list,
 840                                     unsigned int flags)
 841 {
 842         while (commit_list) {
 843                 struct object *object = &commit_list->item->object;
 844                 object->flags |= flags;
 845                 add_pending_object(revs, object, sha1_to_hex(object->sha1));
 846                 commit_list = commit_list->next;
 847         }
 848 }
 849
 850 static void prepare_show_merge(struct rev_info *revs)
 851 {
 852         struct commit_list *bases;
 853         struct commit *head, *other;
 854         unsigned char sha1[20];
 855         const char **prune = NULL;
 856         int i, prune_num = 1; /* counting terminating NULL */
 857
 858         if (get_sha1("HEAD", sha1) || !(head = lookup_commit(sha1)))
 859                 die("--merge without HEAD?");
 860         if (get_sha1("MERGE_HEAD", sha1) || !(other = lookup_commit(sha1)))
 861                 die("--merge without MERGE_HEAD?");
 862         add_pending_object(revs, &head->object, "HEAD");
 863         add_pending_object(revs, &other->object, "MERGE_HEAD");
 864         bases = get_merge_bases(head, other, 1);
 865         add_pending_commit_list(revs, bases, UNINTERESTING);
 866         free_commit_list(bases);
 867         head->object.flags |= SYMMETRIC_LEFT;
 868
 869         if (!active_nr)
 870                 read_cache();
 871         for (i = 0; i < active_nr; i++) {
 872                 struct cache_entry *ce = active_cache[i];
 873                 if (!ce_stage(ce))
 874                         continue;
 875                 if (ce_path_match(ce, revs->prune_data)) {
 876                         prune_num++;
 877                         prune = xrealloc(prune, sizeof(*prune) * prune_num);
 878                         prune[prune_num-2] = ce->name;
 879                         prune[prune_num-1] = NULL;
 880                 }
 881                 while ((i+1 < active_nr) &&
 882                        ce_same_name(ce, active_cache[i+1]))
 883                         i++;
 884         }
 885         revs->prune_data = prune;
 886         revs->limited = 1;
 887 }
 888
 889 int handle_revision_arg(const char *arg, struct rev_info *revs,
 890                         int flags,
 891                         int cant_be_filename)
 892 {
 893         unsigned mode;
 894         char *dotdot;
 895         struct object *object;
 896         unsigned char sha1[20];
 897         int local_flags;
 898
 899         dotdot = strstr(arg, "..");
 900         if (dotdot) {
 901                 unsigned char from_sha1[20];
 902                 const char *next = dotdot + 2;
 903                 const char *this = arg;
 904                 int symmetric = *next == '.';
 905                 unsigned int flags_exclude = flags ^ UNINTERESTING;
 906
 907                 *dotdot = 0;
 908                 next += symmetric;
 909
 910                 if (!*next)
 911                         next = "HEAD";
 912                 if (dotdot == arg)
 913                         this = "HEAD";
 914                 if (!get_sha1(this, from_sha1) &&
 915                     !get_sha1(next, sha1)) {
 916                         struct commit *a, *b;
 917                         struct commit_list *exclude;
 918
 919                         a = lookup_commit_reference(from_sha1);
 920                         b = lookup_commit_reference(sha1);
 921                         if (!a || !b) {
 922                                 die(symmetric ?
 923                                     "Invalid symmetric difference expression %s...%s" :
 924                                     "Invalid revision range %s..%s",
 925                                     arg, next);
 926                         }
 927
 928                         if (!cant_be_filename) {
 929                                 *dotdot = '.';
 930                                 verify_non_filename(revs->prefix, arg);
 931                         }
 932
 933                         if (symmetric) {
 934                                 exclude = get_merge_bases(a, b, 1);
 935                                 add_pending_commit_list(revs, exclude,
 936                                                         flags_exclude);
 937                                 free_commit_list(exclude);
 938                                 a->object.flags |= flags | SYMMETRIC_LEFT;
 939                         } else
 940                                 a->object.flags |= flags_exclude;
 941                         b->object.flags |= flags;
 942                         add_pending_object(revs, &a->object, this);
 943                         add_pending_object(revs, &b->object, next);
 944                         return 0;
 945                 }
 946                 *dotdot = '.';
 947         }
 948         dotdot = strstr(arg, "^@");
 949         if (dotdot && !dotdot[2]) {
 950                 *dotdot = 0;
 951                 if (add_parents_only(revs, arg, flags))
 952                         return 0;
 953                 *dotdot = '^';
 954         }
 955         dotdot = strstr(arg, "^!");
 956         if (dotdot && !dotdot[2]) {
 957                 *dotdot = 0;
 958                 if (!add_parents_only(revs, arg, flags ^ UNINTERESTING))
 959                         *dotdot = '^';
 960         }
 961
 962         local_flags = 0;
 963         if (*arg == '^') {
 964                 local_flags = UNINTERESTING;
 965                 arg++;
 966         }
 967         if (get_sha1_with_mode(arg, sha1, &mode))
 968                 return -1;
 969         if (!cant_be_filename)
 970                 verify_non_filename(revs->prefix, arg);
 971         object = get_reference(revs, arg, sha1, flags ^ local_flags);
 972         add_pending_object_with_mode(revs, object, arg, mode);
 973         return 0;
 974 }
 975
 976 void read_revisions_from_stdin(struct rev_info *revs)
 977 {
 978         char line[1000];
 979
 980         while (fgets(line, sizeof(line), stdin) != NULL) {
 981                 int len = strlen(line);
 982                 if (len && line[len - 1] == '\n')
 983                         line[--len] = '\0';
 984                 if (!len)
 985                         break;
 986                 if (line[0] == '-')
 987                         die("options not supported in --stdin mode");
 988                 if (handle_revision_arg(line, revs, 0, 1))
 989                         die("bad revision '%s'", line);
 990         }
 991 }
 992
 993 static void add_grep(struct rev_info *revs, const char *ptn, enum grep_pat_token what)
 994 {
 995         append_grep_pattern(&revs->grep_filter, ptn, "command line", 0, what);
 996 }
 997
 998 static void add_header_grep(struct rev_info *revs, enum grep_header_field field, const char *pattern)
 999 {
1000         append_header_grep_pattern(&revs->grep_filter, field, pattern);
1001 }
1002
1003 static void add_message_grep(struct rev_info *revs, const char *pattern)
1004 {
1005         add_grep(revs, pattern, GREP_PATTERN_BODY);
1006 }
1007
1008 static int handle_revision_opt(struct rev_info *revs, int argc, const char **argv,
1009                                int *unkc, const char **unkv)
1010 {
1011         const char *arg = argv[0];
1012
1013         /* pseudo revision arguments */
1014         if (!strcmp(arg, "--all") || !strcmp(arg, "--branches") ||
1015             !strcmp(arg, "--tags") || !strcmp(arg, "--remotes") ||
1016             !strcmp(arg, "--reflog") || !strcmp(arg, "--not") ||
1017             !strcmp(arg, "--no-walk") || !strcmp(arg, "--do-walk"))
1018         {
1019                 unkv[(*unkc)++] = arg;
1020                 return 1;
1021         }
1022
1023         if (!prefixcmp(arg, "--max-count=")) {
1024                 revs->max_count = atoi(arg + 12);
1025         } else if (!prefixcmp(arg, "--skip=")) {
1026                 revs->skip_count = atoi(arg + 7);
1027         } else if ((*arg == '-') && isdigit(arg[1])) {
1028         /* accept -<digit>, like traditional "head" */
1029                 revs->max_count = atoi(arg + 1);
1030         } else if (!strcmp(arg, "-n")) {
1031                 if (argc <= 1)
1032                         return error("-n requires an argument");
1033                 revs->max_count = atoi(argv[1]);
1034                 return 2;
1035         } else if (!prefixcmp(arg, "-n")) {
1036                 revs->max_count = atoi(arg + 2);
1037         } else if (!prefixcmp(arg, "--max-age=")) {
1038                 revs->max_age = atoi(arg + 10);
1039         } else if (!prefixcmp(arg, "--since=")) {
1040                 revs->max_age = approxidate(arg + 8);
1041         } else if (!prefixcmp(arg, "--after=")) {
1042                 revs->max_age = approxidate(arg + 8);
1043         } else if (!prefixcmp(arg, "--min-age=")) {
1044                 revs->min_age = atoi(arg + 10);
1045         } else if (!prefixcmp(arg, "--before=")) {
1046                 revs->min_age = approxidate(arg + 9);
1047         } else if (!prefixcmp(arg, "--until=")) {
1048                 revs->min_age = approxidate(arg + 8);
1049         } else if (!strcmp(arg, "--first-parent")) {
1050                 revs->first_parent_only = 1;
1051         } else if (!strcmp(arg, "-g") || !strcmp(arg, "--walk-reflogs")) {
1052                 init_reflog_walk(&revs->reflog_info);
1053         } else if (!strcmp(arg, "--default")) {
1054                 if (argc <= 1)
1055                         return error("bad --default argument");
1056                 revs->def = argv[1];
1057                 return 2;
1058         } else if (!strcmp(arg, "--merge")) {
1059                 revs->show_merge = 1;
1060         } else if (!strcmp(arg, "--topo-order")) {
1061                 revs->lifo = 1;
1062                 revs->topo_order = 1;
1063         } else if (!strcmp(arg, "--simplify-merges")) {
1064                 revs->simplify_merges = 1;
1065                 revs->rewrite_parents = 1;
1066                 revs->simplify_history = 0;
1067                 revs->limited = 1;
1068         } else if (!strcmp(arg, "--simplify-by-decoration")) {
1069                 revs->simplify_merges = 1;
1070                 revs->rewrite_parents = 1;
1071                 revs->simplify_history = 0;
1072                 revs->simplify_by_decoration = 1;
1073                 revs->limited = 1;
1074                 revs->prune = 1;
1075                 load_ref_decorations(DECORATE_SHORT_REFS);
1076         } else if (!strcmp(arg, "--date-order")) {
1077                 revs->lifo = 0;
1078                 revs->topo_order = 1;
1079         } else if (!prefixcmp(arg, "--early-output")) {
1080                 int count = 100;
1081                 switch (arg[14]) {
1082                 case '=':
1083                         count = atoi(arg+15);
1084                         /* Fallthrough */
1085                 case 0:
1086                         revs->topo_order = 1;
1087                        revs->early_output = count;
1088                 }
1089         } else if (!strcmp(arg, "--parents")) {
1090                 revs->rewrite_parents = 1;
1091                 revs->print_parents = 1;
1092         } else if (!strcmp(arg, "--dense")) {
1093                 revs->dense = 1;
1094         } else if (!strcmp(arg, "--sparse")) {
1095                 revs->dense = 0;
1096         } else if (!strcmp(arg, "--show-all")) {
1097                 revs->show_all = 1;
1098         } else if (!strcmp(arg, "--remove-empty")) {
1099                 revs->remove_empty_trees = 1;
1100         } else if (!strcmp(arg, "--merges")) {
1101                 revs->merges_only = 1;
1102         } else if (!strcmp(arg, "--no-merges")) {
1103                 revs->no_merges = 1;
1104         } else if (!strcmp(arg, "--boundary")) {
1105                 revs->boundary = 1;
1106         } else if (!strcmp(arg, "--left-right")) {
1107                 revs->left_right = 1;
1108         } else if (!strcmp(arg, "--cherry-pick")) {
1109                 revs->cherry_pick = 1;
1110                 revs->limited = 1;
1111         } else if (!strcmp(arg, "--objects")) {
1112                 revs->tag_objects = 1;
1113                 revs->tree_objects = 1;
1114                 revs->blob_objects = 1;
1115         } else if (!strcmp(arg, "--objects-edge")) {
1116                 revs->tag_objects = 1;
1117                 revs->tree_objects = 1;
1118                 revs->blob_objects = 1;
1119                 revs->edge_hint = 1;
1120         } else if (!strcmp(arg, "--unpacked")) {
1121                 revs->unpacked = 1;
1122         } else if (!prefixcmp(arg, "--unpacked=")) {
1123                 die("--unpacked=<packfile> no longer supported.");
1124         } else if (!strcmp(arg, "-r")) {
1125                 revs->diff = 1;
1126                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1127         } else if (!strcmp(arg, "-t")) {
1128                 revs->diff = 1;
1129                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1130                 DIFF_OPT_SET(&revs->diffopt, TREE_IN_RECURSIVE);
1131         } else if (!strcmp(arg, "-m")) {
1132                 revs->ignore_merges = 0;
1133         } else if (!strcmp(arg, "-c")) {
1134                 revs->diff = 1;
1135                 revs->dense_combined_merges = 0;
1136                 revs->combine_merges = 1;
1137         } else if (!strcmp(arg, "--cc")) {
1138                 revs->diff = 1;
1139                 revs->dense_combined_merges = 1;
1140                 revs->combine_merges = 1;
1141         } else if (!strcmp(arg, "-v")) {
1142                 revs->verbose_header = 1;
1143         } else if (!strcmp(arg, "--pretty")) {
1144                 revs->verbose_header = 1;
1145                 get_commit_format(arg+8, revs);
1146         } else if (!prefixcmp(arg, "--pretty=") || !prefixcmp(arg, "--format=")) {
1147                 revs->verbose_header = 1;
1148                 get_commit_format(arg+9, revs);
1149         } else if (!strcmp(arg, "--oneline")) {
1150                 revs->verbose_header = 1;
1151                 get_commit_format("oneline", revs);
1152                 revs->abbrev_commit = 1;
1153         } else if (!strcmp(arg, "--graph")) {
1154                 revs->topo_order = 1;
1155                 revs->rewrite_parents = 1;
1156                 revs->graph = graph_init(revs);
1157         } else if (!strcmp(arg, "--root")) {
1158                 revs->show_root_diff = 1;
1159         } else if (!strcmp(arg, "--no-commit-id")) {
1160                 revs->no_commit_id = 1;
1161         } else if (!strcmp(arg, "--always")) {
1162                 revs->always_show_header = 1;
1163         } else if (!strcmp(arg, "--no-abbrev")) {
1164                 revs->abbrev = 0;
1165         } else if (!strcmp(arg, "--abbrev")) {
1166                 revs->abbrev = DEFAULT_ABBREV;
1167         } else if (!prefixcmp(arg, "--abbrev=")) {
1168                 revs->abbrev = strtoul(arg + 9, NULL, 10);
1169                 if (revs->abbrev < MINIMUM_ABBREV)
1170                         revs->abbrev = MINIMUM_ABBREV;
1171                 else if (revs->abbrev > 40)
1172                         revs->abbrev = 40;
1173         } else if (!strcmp(arg, "--abbrev-commit")) {
1174                 revs->abbrev_commit = 1;
1175         } else if (!strcmp(arg, "--full-diff")) {
1176                 revs->diff = 1;
1177                 revs->full_diff = 1;
1178         } else if (!strcmp(arg, "--full-history")) {
1179                 revs->simplify_history = 0;
1180         } else if (!strcmp(arg, "--relative-date")) {
1181                 revs->date_mode = DATE_RELATIVE;
1182         } else if (!strncmp(arg, "--date=", 7)) {
1183                 revs->date_mode = parse_date_format(arg + 7);
1184         } else if (!strcmp(arg, "--log-size")) {
1185                 revs->show_log_size = 1;
1186         }
1187         /*
1188          * Grepping the commit log
1189          */
1190         else if (!prefixcmp(arg, "--author=")) {
1191                 add_header_grep(revs, GREP_HEADER_AUTHOR, arg+9);
1192         } else if (!prefixcmp(arg, "--committer=")) {
1193                 add_header_grep(revs, GREP_HEADER_COMMITTER, arg+12);
1194         } else if (!prefixcmp(arg, "--grep=")) {
1195                 add_message_grep(revs, arg+7);
1196         } else if (!strcmp(arg, "--extended-regexp") || !strcmp(arg, "-E")) {
1197                 revs->grep_filter.regflags |= REG_EXTENDED;
1198         } else if (!strcmp(arg, "--regexp-ignore-case") || !strcmp(arg, "-i")) {
1199                 revs->grep_filter.regflags |= REG_ICASE;
1200         } else if (!strcmp(arg, "--fixed-strings") || !strcmp(arg, "-F")) {
1201                 revs->grep_filter.fixed = 1;
1202         } else if (!strcmp(arg, "--all-match")) {
1203                 revs->grep_filter.all_match = 1;
1204         } else if (!prefixcmp(arg, "--encoding=")) {
1205                 arg += 11;
1206                 if (strcmp(arg, "none"))
1207                         git_log_output_encoding = xstrdup(arg);
1208                 else
1209                         git_log_output_encoding = "";
1210         } else if (!strcmp(arg, "--reverse")) {
1211                 revs->reverse ^= 1;
1212         } else if (!strcmp(arg, "--children")) {
1213                 revs->children.name = "children";
1214                 revs->limited = 1;
1215         } else {
1216                 int opts = diff_opt_parse(&revs->diffopt, argv, argc);
1217                 if (!opts)
1218                         unkv[(*unkc)++] = arg;
1219                 return opts;
1220         }
1221
1222         return 1;
1223 }
1224
1225 void parse_revision_opt(struct rev_info *revs, struct parse_opt_ctx_t *ctx,
1226                         const struct option *options,
1227                         const char * const usagestr[])
1228 {
1229         int n = handle_revision_opt(revs, ctx->argc, ctx->argv,
1230                                     &ctx->cpidx, ctx->out);
1231         if (n <= 0) {
1232                 error("unknown option `%s'", ctx->argv[0]);
1233                 usage_with_options(usagestr, options);
1234         }
1235         ctx->argv += n;
1236         ctx->argc -= n;
1237 }
1238
1239 /*
1240  * Parse revision information, filling in the "rev_info" structure,
1241  * and removing the used arguments from the argument list.
1242  *
1243  * Returns the number of arguments left that weren't recognized
1244  * (which are also moved to the head of the argument list)
1245  */
1246 int setup_revisions(int argc, const char **argv, struct rev_info *revs, const char *def)
1247 {
1248         int i, flags, left, seen_dashdash;
1249
1250         /* First, search for "--" */
1251         seen_dashdash = 0;
1252         for (i = 1; i < argc; i++) {
1253                 const char *arg = argv[i];
1254                 if (strcmp(arg, "--"))
1255                         continue;
1256                 argv[i] = NULL;
1257                 argc = i;
1258                 if (argv[i + 1])
1259                         revs->prune_data = get_pathspec(revs->prefix, argv + i + 1);
1260                 seen_dashdash = 1;
1261                 break;
1262         }
1263
1264         /* Second, deal with arguments and options */
1265         flags = 0;
1266         for (left = i = 1; i < argc; i++) {
1267                 const char *arg = argv[i];
1268                 if (*arg == '-') {
1269                         int opts;
1270
1271                         if (!strcmp(arg, "--all")) {
1272                                 handle_refs(revs, flags, for_each_ref);
1273                                 handle_refs(revs, flags, head_ref);
1274                                 continue;
1275                         }
1276                         if (!strcmp(arg, "--branches")) {
1277                                 handle_refs(revs, flags, for_each_branch_ref);
1278                                 continue;
1279                         }
1280                         if (!strcmp(arg, "--tags")) {
1281                                 handle_refs(revs, flags, for_each_tag_ref);
1282                                 continue;
1283                         }
1284                         if (!strcmp(arg, "--remotes")) {
1285                                 handle_refs(revs, flags, for_each_remote_ref);
1286                                 continue;
1287                         }
1288                         if (!strcmp(arg, "--reflog")) {
1289                                 handle_reflog(revs, flags);
1290                                 continue;
1291                         }
1292                         if (!strcmp(arg, "--not")) {
1293                                 flags ^= UNINTERESTING;
1294                                 continue;
1295                         }
1296                         if (!strcmp(arg, "--no-walk")) {
1297                                 revs->no_walk = 1;
1298                                 continue;
1299                         }
1300                         if (!strcmp(arg, "--do-walk")) {
1301                                 revs->no_walk = 0;
1302                                 continue;
1303                         }
1304
1305                         opts = handle_revision_opt(revs, argc - i, argv + i, &left, argv);
1306                         if (opts > 0) {
1307                                 i += opts - 1;
1308                                 continue;
1309                         }
1310                         if (opts < 0)
1311                                 exit(128);
1312                         continue;
1313                 }
1314
1315                 if (handle_revision_arg(arg, revs, flags, seen_dashdash)) {
1316                         int j;
1317                         if (seen_dashdash || *arg == '^')
1318                                 die("bad revision '%s'", arg);
1319
1320                         /* If we didn't have a "--":
1321                          * (1) all filenames must exist;
1322                          * (2) all rev-args must not be interpretable
1323                          *     as a valid filename.
1324                          * but the latter we have checked in the main loop.
1325                          */
1326                         for (j = i; j < argc; j++)
1327                                 verify_filename(revs->prefix, argv[j]);
1328
1329                         revs->prune_data = get_pathspec(revs->prefix,
1330                                                         argv + i);
1331                         break;
1332                 }
1333         }
1334
1335         if (revs->def == NULL)
1336                 revs->def = def;
1337         if (revs->show_merge)
1338                 prepare_show_merge(revs);
1339         if (revs->def && !revs->pending.nr) {
1340                 unsigned char sha1[20];
1341                 struct object *object;
1342                 unsigned mode;
1343                 if (get_sha1_with_mode(revs->def, sha1, &mode))
1344                         die("bad default revision '%s'", revs->def);
1345                 object = get_reference(revs, revs->def, sha1, 0);
1346                 add_pending_object_with_mode(revs, object, revs->def, mode);
1347         }
1348
1349         /* Did the user ask for any diff output? Run the diff! */
1350         if (revs->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT)
1351                 revs->diff = 1;
1352
1353         /* Pickaxe, diff-filter and rename following need diffs */
1354         if (revs->diffopt.pickaxe ||
1355             revs->diffopt.filter ||
1356             DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1357                 revs->diff = 1;
1358
1359         if (revs->topo_order)
1360                 revs->limited = 1;
1361
1362         if (revs->prune_data) {
1363                 diff_tree_setup_paths(revs->prune_data, &revs->pruning);
1364                 /* Can't prune commits with rename following: the paths change.. */
1365                 if (!DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
1366                         revs->prune = 1;
1367                 if (!revs->full_diff)
1368                         diff_tree_setup_paths(revs->prune_data, &revs->diffopt);
1369         }
1370         if (revs->combine_merges) {
1371                 revs->ignore_merges = 0;
1372                 if (revs->dense_combined_merges && !revs->diffopt.output_format)
1373                         revs->diffopt.output_format = DIFF_FORMAT_PATCH;
1374         }
1375         revs->diffopt.abbrev = revs->abbrev;
1376         if (diff_setup_done(&revs->diffopt) < 0)
1377                 die("diff_setup_done failed");
1378
1379         compile_grep_patterns(&revs->grep_filter);
1380
1381         if (revs->reverse && revs->reflog_info)
1382                 die("cannot combine --reverse with --walk-reflogs");
1383         if (revs->rewrite_parents && revs->children.name)
1384                 die("cannot combine --parents and --children");
1385
1386         /*
1387          * Limitations on the graph functionality
1388          */
1389         if (revs->reverse && revs->graph)
1390                 die("cannot combine --reverse with --graph");
1391
1392         if (revs->reflog_info && revs->graph)
1393                 die("cannot combine --walk-reflogs with --graph");
1394
1395         /* limits on caching
1396          * todo: implement this functionality */
1397         if (revs->prune || revs->diff)
1398                 revs->dont_cache_me = 1;
1399
1400         return left;
1401 }
1402
1403 static void add_child(struct rev_info *revs, struct commit *parent, struct commit *child)
1404 {
1405         struct commit_list *l = xcalloc(1, sizeof(*l));
1406
1407         l->item = child;
1408         l->next = add_decoration(&revs->children, &parent->object, l);
1409 }
1410
1411 static int remove_duplicate_parents(struct commit *commit)
1412 {
1413         struct commit_list **pp, *p;
1414         int surviving_parents;
1415
1416         /* Examine existing parents while marking ones we have seen... */
1417         pp = &commit->parents;
1418         while ((p = *pp) != NULL) {
1419                 struct commit *parent = p->item;
1420                 if (parent->object.flags & TMP_MARK) {
1421                         *pp = p->next;
1422                         continue;
1423                 }
1424                 parent->object.flags |= TMP_MARK;
1425                 pp = &p->next;
1426         }
1427         /* count them while clearing the temporary mark */
1428         surviving_parents = 0;
1429         for (p = commit->parents; p; p = p->next) {
1430                 p->item->object.flags &= ~TMP_MARK;
1431                 surviving_parents++;
1432         }
1433         return surviving_parents;
1434 }
1435
1436 struct merge_simplify_state {
1437         struct commit *simplified;
1438 };
1439
1440 static struct merge_simplify_state *locate_simplify_state(struct rev_info *revs, struct commit *commit)
1441 {
1442         struct merge_simplify_state *st;
1443
1444         st = lookup_decoration(&revs->merge_simplification, &commit->object);
1445         if (!st) {
1446                 st = xcalloc(1, sizeof(*st));
1447                 add_decoration(&revs->merge_simplification, &commit->object, st);
1448         }
1449         return st;
1450 }
1451
1452 static struct commit_list **simplify_one(struct rev_info *revs, struct commit *commit, struct commit_list **tail)
1453 {
1454         struct commit_list *p;
1455         struct merge_simplify_state *st, *pst;
1456         int cnt;
1457
1458         st = locate_simplify_state(revs, commit);
1459
1460         /*
1461          * Have we handled this one?
1462          */
1463         if (st->simplified)
1464                 return tail;
1465
1466         /*
1467          * An UNINTERESTING commit simplifies to itself, so does a
1468          * root commit.  We do not rewrite parents of such commit
1469          * anyway.
1470          */
1471         if ((commit->object.flags & UNINTERESTING) || !commit->parents) {
1472                 st->simplified = commit;
1473                 return tail;
1474         }
1475
1476         /*
1477          * Do we know what commit all of our parents should be rewritten to?
1478          * Otherwise we are not ready to rewrite this one yet.
1479          */
1480         for (cnt = 0, p = commit->parents; p; p = p->next) {
1481                 pst = locate_simplify_state(revs, p->item);
1482                 if (!pst->simplified) {
1483                         tail = &commit_list_insert(p->item, tail)->next;
1484                         cnt++;
1485                 }
1486         }
1487         if (cnt) {
1488                 tail = &commit_list_insert(commit, tail)->next;
1489                 return tail;
1490         }
1491
1492         /*
1493          * Rewrite our list of parents.
1494          */
1495         for (p = commit->parents; p; p = p->next) {
1496                 pst = locate_simplify_state(revs, p->item);
1497                 p->item = pst->simplified;
1498         }
1499         cnt = remove_duplicate_parents(commit);
1500
1501         /*
1502          * It is possible that we are a merge and one side branch
1503          * does not have any commit that touches the given paths;
1504          * in such a case, the immediate parents will be rewritten
1505          * to different commits.
1506          *
1507          *      o----X          X: the commit we are looking at;
1508          *     /    /           o: a commit that touches the paths;
1509          * ---o----'
1510          *
1511          * Further reduce the parents by removing redundant parents.
1512          */
1513         if (1 < cnt) {
1514                 struct commit_list *h = reduce_heads(commit->parents);
1515                 cnt = commit_list_count(h);
1516                 free_commit_list(commit->parents);
1517                 commit->parents = h;
1518         }
1519
1520         /*
1521          * A commit simplifies to itself if it is a root, if it is
1522          * UNINTERESTING, if it touches the given paths, or if it is a
1523          * merge and its parents simplifies to more than one commits
1524          * (the first two cases are already handled at the beginning of
1525          * this function).
1526          *
1527          * Otherwise, it simplifies to what its sole parent simplifies to.
1528          */
1529         if (!cnt ||
1530             (commit->object.flags & UNINTERESTING) ||
1531             !(commit->object.flags & TREESAME) ||
1532             (1 < cnt))
1533                 st->simplified = commit;
1534         else {
1535                 pst = locate_simplify_state(revs, commit->parents->item);
1536                 st->simplified = pst->simplified;
1537         }
1538         return tail;
1539 }
1540
1541 static void simplify_merges(struct rev_info *revs)
1542 {
1543         struct commit_list *list;
1544         struct commit_list *yet_to_do, **tail;
1545
1546         if (!revs->topo_order)
1547                 sort_in_topological_order(&revs->commits, revs->lifo);
1548         if (!revs->prune)
1549                 return;
1550
1551         /* feed the list reversed */
1552         yet_to_do = NULL;
1553         for (list = revs->commits; list; list = list->next)
1554                 commit_list_insert(list->item, &yet_to_do);
1555         while (yet_to_do) {
1556                 list = yet_to_do;
1557                 yet_to_do = NULL;
1558                 tail = &yet_to_do;
1559                 while (list) {
1560                         struct commit *commit = list->item;
1561                         struct commit_list *next = list->next;
1562                         free(list);
1563                         list = next;
1564                         tail = simplify_one(revs, commit, tail);
1565                 }
1566         }
1567
1568         /* clean up the result, removing the simplified ones */
1569         list = revs->commits;
1570         revs->commits = NULL;
1571         tail = &revs->commits;
1572         while (list) {
1573                 struct commit *commit = list->item;
1574                 struct commit_list *next = list->next;
1575                 struct merge_simplify_state *st;
1576                 free(list);
1577                 list = next;
1578                 st = locate_simplify_state(revs, commit);
1579                 if (st->simplified == commit)
1580                         tail = &commit_list_insert(commit, tail)->next;
1581         }
1582 }
1583
1584 static void set_children(struct rev_info *revs)
1585 {
1586         struct commit_list *l;
1587         for (l = revs->commits; l; l = l->next) {
1588                 struct commit *commit = l->item;
1589                 struct commit_list *p;
1590
1591                 for (p = commit->parents; p; p = p->next)
1592                         add_child(revs, p->item, commit);
1593         }
1594 }
1595
1596 int prepare_revision_walk(struct rev_info *revs)
1597 {
1598         int nr = revs->pending.nr;
1599         struct object_array_entry *e, *list;
1600
1601         e = list = revs->pending.objects;
1602         revs->pending.nr = 0;
1603         revs->pending.alloc = 0;
1604         revs->pending.objects = NULL;
1605         while (--nr >= 0) {
1606                 struct commit *commit = handle_commit(revs, e->item, e->name);
1607                 if (commit) {
1608                         if (!(commit->object.flags & SEEN)) {
1609                                 commit->object.flags |= SEEN;
1610                                 insert_by_date(commit, &revs->commits);
1611                         }
1612                 }
1613                 e++;
1614         }
1615         free(list);
1616
1617         if (revs->no_walk)
1618                 return 0;
1619         if (revs->limited)
1620                 if (limit_list(revs) < 0)
1621                         return -1;
1622         if (revs->topo_order)
1623                 sort_in_topological_order(&revs->commits, revs->lifo);
1624         if (revs->simplify_merges)
1625                 simplify_merges(revs);
1626         if (revs->children.name)
1627                 set_children(revs);
1628         return 0;
1629 }
1630
1631 enum rewrite_result {
1632         rewrite_one_ok,
1633         rewrite_one_noparents,
1634         rewrite_one_error,
1635 };
1636
1637 static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp)
1638 {
1639         struct commit_list *cache = NULL;
1640
1641         for (;;) {
1642                 struct commit *p = *pp;
1643                 if (!revs->limited)
1644                         if (add_parents_to_list(revs, p, &revs->commits, &cache) < 0)
1645                                 return rewrite_one_error;
1646                 if (p->parents && p->parents->next)
1647                         return rewrite_one_ok;
1648                 if (p->object.flags & UNINTERESTING)
1649                         return rewrite_one_ok;
1650                 if (!(p->object.flags & TREESAME))
1651                         return rewrite_one_ok;
1652                 if (!p->parents)
1653                         return rewrite_one_noparents;
1654                 *pp = p->parents->item;
1655         }
1656 }
1657
1658 static int rewrite_parents(struct rev_info *revs, struct commit *commit)
1659 {
1660         struct commit_list **pp = &commit->parents;
1661         while (*pp) {
1662                 struct commit_list *parent = *pp;
1663                 switch (rewrite_one(revs, &parent->item)) {
1664                 case rewrite_one_ok:
1665                         break;
1666                 case rewrite_one_noparents:
1667                         *pp = parent->next;
1668                         continue;
1669                 case rewrite_one_error:
1670                         return -1;
1671                 }
1672                 pp = &parent->next;
1673         }
1674         remove_duplicate_parents(commit);
1675         return 0;
1676 }
1677
1678 static int commit_match(struct commit *commit, struct rev_info *opt)
1679 {
1680         if (!opt->grep_filter.pattern_list)
1681                 return 1;
1682         if (!commit->object.parsed)
1683                 parse_commit(commit);
1684         return grep_buffer(&opt->grep_filter,
1685                            NULL, /* we say nothing, not even filename */
1686                            commit->buffer, strlen(commit->buffer));
1687 }
1688
1689 static inline int want_ancestry(struct rev_info *revs)
1690 {
1691         return (revs->rewrite_parents || revs->children.name);
1692 }
1693
1694 enum commit_action get_commit_action(struct rev_info *revs, struct commit *commit)
1695 {
1696         if (commit->object.flags & SHOWN)
1697                 return commit_ignore;
1698         if (revs->unpacked && has_sha1_pack(commit->object.sha1))
1699                 return commit_ignore;
1700         if (revs->show_all)
1701                 return commit_show;
1702         if (commit->object.flags & UNINTERESTING)
1703                 return commit_ignore;
1704         if (revs->min_age != -1 && (commit->date > revs->min_age))
1705                 return commit_ignore;
1706         if (revs->no_merges && commit->parents && commit->parents->next)
1707                 return commit_ignore;
1708         if (revs->merges_only && !(commit->parents && commit->parents->next))
1709                 return commit_ignore;
1710         if (!commit_match(commit, revs))
1711                 return commit_ignore;
1712         if (revs->prune && revs->dense) {
1713                 /* Commit without changes? */
1714                 if (commit->object.flags & TREESAME) {
1715                         /* drop merges unless we want parenthood */
1716                         if (!want_ancestry(revs))
1717                                 return commit_ignore;
1718                         /* non-merge - always ignore it */
1719                         if (!commit->parents || !commit->parents->next)
1720                                 return commit_ignore;
1721                 }
1722         }
1723         return commit_show;
1724 }
1725
1726 enum commit_action simplify_commit(struct rev_info *revs, struct commit *commit)
1727 {
1728         enum commit_action action = get_commit_action(revs, commit);
1729
1730         if (action == commit_show &&
1731             !revs->show_all &&
1732             revs->prune && revs->dense && want_ancestry(revs)) {
1733                 if (rewrite_parents(revs, commit) < 0)
1734                         return commit_error;
1735         }
1736         return action;
1737 }
1738
1739 static struct commit *get_revision_1(struct rev_info *revs)
1740 {
1741         if (!revs->commits)
1742                 return NULL;
1743
1744         do {
1745                 struct commit_list *entry = revs->commits;
1746                 struct commit *commit = entry->item;
1747                 struct object *obj = &commit->object;
1748
1749                 revs->commits = entry->next;
1750                 free(entry);
1751
1752                 if (revs->reflog_info)
1753                         fake_reflog_parent(revs->reflog_info, commit);
1754
1755                 /*
1756                  * If we haven't done the list limiting, we need to look at
1757                  * the parents here. We also need to do the date-based limiting
1758                  * that we'd otherwise have done in limit_list().
1759                  */
1760                 if (!revs->limited) {
1761                         if (revs->max_age != -1 &&
1762                             (commit->date < revs->max_age))
1763                                 continue;
1764
1765                         if (!revs->dont_cache_me) {
1766                                 struct commit_list *queue = 0, **queuep = &queue;
1767                                 unsigned char *cache_sha1;
1768
1769                                 if (obj->flags & ADDED)
1770                                         goto skip_parenting;
1771
1772                                 cache_sha1 = get_cache_slice(commit);
1773                                 if (cache_sha1) {
1774                                         if (!traverse_cache_slice(revs, cache_sha1, commit, 0, 0, &queuep, &revs->commits)) {
1775                                                 struct commit_list *work = revs->commits;
1776
1777                                                 /* attach queue to end of ->commits */
1778                                                 while (work && work->next)
1779                                                         work = work->next;
1780
1781                                                 if (work)
1782                                                         work->next = queue;
1783                                                 else
1784                                                         revs->commits = queue;
1785
1786                                                 goto skip_parenting;
1787                                         }
1788                                 }
1789                         }
1790
1791                         if (add_parents_to_list(revs, commit, &revs->commits, NULL) < 0)
1792                                 die("Failed to traverse parents of commit %s",
1793                                     sha1_to_hex(commit->object.sha1));
1794                 }
1795
1796 skip_parenting:
1797                 switch (simplify_commit(revs, commit)) {
1798                 case commit_ignore:
1799                         continue;
1800                 case commit_error:
1801                         die("Failed to simplify parents of commit %s",
1802                             sha1_to_hex(commit->object.sha1));
1803                 default:
1804                         return commit;
1805                 }
1806         } while (revs->commits);
1807         return NULL;
1808 }
1809
1810 static void gc_boundary(struct object_array *array)
1811 {
1812         unsigned nr = array->nr;
1813         unsigned alloc = array->alloc;
1814         struct object_array_entry *objects = array->objects;
1815
1816         if (alloc <= nr) {
1817                 unsigned i, j;
1818                 for (i = j = 0; i < nr; i++) {
1819                         if (objects[i].item->flags & SHOWN)
1820                                 continue;
1821                         if (i != j)
1822                                 objects[j] = objects[i];
1823                         j++;
1824                 }
1825                 for (i = j; i < nr; i++)
1826                         objects[i].item = NULL;
1827                 array->nr = j;
1828         }
1829 }
1830
1831 static void create_boundary_commit_list(struct rev_info *revs)
1832 {
1833         unsigned i;
1834         struct commit *c;
1835         struct object_array *array = &revs->boundary_commits;
1836         struct object_array_entry *objects = array->objects;
1837
1838         /*
1839          * If revs->commits is non-NULL at this point, an error occurred in
1840          * get_revision_1().  Ignore the error and continue printing the
1841          * boundary commits anyway.  (This is what the code has always
1842          * done.)
1843          */
1844         if (revs->commits) {
1845                 free_commit_list(revs->commits);
1846                 revs->commits = NULL;
1847         }
1848
1849         /*
1850          * Put all of the actual boundary commits from revs->boundary_commits
1851          * into revs->commits
1852          */
1853         for (i = 0; i < array->nr; i++) {
1854                 c = (struct commit *)(objects[i].item);
1855                 if (!c)
1856                         continue;
1857                 if (!(c->object.flags & CHILD_SHOWN))
1858                         continue;
1859                 if (c->object.flags & (SHOWN | BOUNDARY))
1860                         continue;
1861                 c->object.flags |= BOUNDARY;
1862                 commit_list_insert(c, &revs->commits);
1863         }
1864
1865         /*
1866          * If revs->topo_order is set, sort the boundary commits
1867          * in topological order
1868          */
1869         sort_in_topological_order(&revs->commits, revs->lifo);
1870 }
1871
1872 static struct commit *get_revision_internal(struct rev_info *revs)
1873 {
1874         struct commit *c = NULL;
1875         struct commit_list *l;
1876
1877         if (revs->boundary == 2) {
1878                 /*
1879                  * All of the normal commits have already been returned,
1880                  * and we are now returning boundary commits.
1881                  * create_boundary_commit_list() has populated
1882                  * revs->commits with the remaining commits to return.
1883                  */
1884                 c = pop_commit(&revs->commits);
1885                 if (c)
1886                         c->object.flags |= SHOWN;
1887                 return c;
1888         }
1889
1890         /*
1891          * Now pick up what they want to give us
1892          */
1893         c = get_revision_1(revs);
1894         if (c) {
1895                 while (0 < revs->skip_count) {
1896                         revs->skip_count--;
1897                         c = get_revision_1(revs);
1898                         if (!c)
1899                                 break;
1900                 }
1901         }
1902
1903         /*
1904          * Check the max_count.
1905          */
1906         switch (revs->max_count) {
1907         case -1:
1908                 break;
1909         case 0:
1910                 c = NULL;
1911                 break;
1912         default:
1913                 revs->max_count--;
1914         }
1915
1916         if (c)
1917                 c->object.flags |= SHOWN;
1918
1919         if (!revs->boundary) {
1920                 return c;
1921         }
1922
1923         if (!c) {
1924                 /*
1925                  * get_revision_1() runs out the commits, and
1926                  * we are done computing the boundaries.
1927                  * switch to boundary commits output mode.
1928                  */
1929                 revs->boundary = 2;
1930
1931                 /*
1932                  * Update revs->commits to contain the list of
1933                  * boundary commits.
1934                  */
1935                 create_boundary_commit_list(revs);
1936
1937                 return get_revision_internal(revs);
1938         }
1939
1940         /*
1941          * boundary commits are the commits that are parents of the
1942          * ones we got from get_revision_1() but they themselves are
1943          * not returned from get_revision_1().  Before returning
1944          * 'c', we need to mark its parents that they could be boundaries.
1945          */
1946
1947         for (l = c->parents; l; l = l->next) {
1948                 struct object *p;
1949                 p = &(l->item->object);
1950                 if (p->flags & (CHILD_SHOWN | SHOWN))
1951                         continue;
1952                 p->flags |= CHILD_SHOWN;
1953                 gc_boundary(&revs->boundary_commits);
1954                 add_object_array(p, NULL, &revs->boundary_commits);
1955         }
1956
1957         return c;
1958 }
1959
1960 struct commit *get_revision(struct rev_info *revs)
1961 {
1962         struct commit *c;
1963         struct commit_list *reversed;
1964
1965         if (revs->reverse) {
1966                 reversed = NULL;
1967                 while ((c = get_revision_internal(revs))) {
1968                         commit_list_insert(c, &reversed);
1969                 }
1970                 revs->commits = reversed;
1971                 revs->reverse = 0;
1972                 revs->reverse_output_stage = 1;
1973         }
1974
1975         if (revs->reverse_output_stage)
1976                 return pop_commit(&revs->commits);
1977
1978         c = get_revision_internal(revs);
1979         if (c && revs->graph)
1980                 graph_update(revs->graph, c);
1981         return c;
1982 }