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