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 "string-list.h"
  16 #include "line-log.h"
  17 #include "mailmap.h"
  18 #include "commit-slab.h"
  19 #include "dir.h"
  20 #include "cache-tree.h"
  21
  22 volatile show_early_output_fn_t show_early_output;
  23
  24 char *path_name(const struct name_path *path, const char *name)
  25 {
  26         const struct name_path *p;
  27         char *n, *m;
  28         int nlen = strlen(name);
  29         int len = nlen + 1;
  30
  31         for (p = path; p; p = p->up) {
  32                 if (p->elem_len)
  33                         len += p->elem_len + 1;
  34         }
  35         n = xmalloc(len);
  36         m = n + len - (nlen + 1);
  37         strcpy(m, name);
  38         for (p = path; p; p = p->up) {
  39                 if (p->elem_len) {
  40                         m -= p->elem_len + 1;
  41                         memcpy(m, p->elem, p->elem_len);
  42                         m[p->elem_len] = '/';
  43                 }
  44         }
  45         return n;
  46 }
  47
  48 static int show_path_component_truncated(FILE *out, const char *name, int len)
  49 {
  50         int cnt;
  51         for (cnt = 0; cnt < len; cnt++) {
  52                 int ch = name[cnt];
  53                 if (!ch || ch == '\n')
  54                         return -1;
  55                 fputc(ch, out);
  56         }
  57         return len;
  58 }
  59
  60 static int show_path_truncated(FILE *out, const struct name_path *path)
  61 {
  62         int emitted, ours;
  63
  64         if (!path)
  65                 return 0;
  66         emitted = show_path_truncated(out, path->up);
  67         if (emitted < 0)
  68                 return emitted;
  69         if (emitted)
  70                 fputc('/', out);
  71         ours = show_path_component_truncated(out, path->elem, path->elem_len);
  72         if (ours < 0)
  73                 return ours;
  74         return ours || emitted;
  75 }
  76
  77 void show_object_with_name(FILE *out, struct object *obj,
  78                            const struct name_path *path, const char *component)
  79 {
  80         struct name_path leaf;
  81         leaf.up = (struct name_path *)path;
  82         leaf.elem = component;
  83         leaf.elem_len = strlen(component);
  84
  85         fprintf(out, "%s ", sha1_to_hex(obj->sha1));
  86         show_path_truncated(out, &leaf);
  87         fputc('\n', out);
  88 }
  89
  90 static void mark_blob_uninteresting(struct blob *blob)
  91 {
  92         if (!blob)
  93                 return;
  94         if (blob->object.flags & UNINTERESTING)
  95                 return;
  96         blob->object.flags |= UNINTERESTING;
  97 }
  98
  99 static void mark_tree_contents_uninteresting(struct tree *tree)
 100 {
 101         struct tree_desc desc;
 102         struct name_entry entry;
 103         struct object *obj = &tree->object;
 104
 105         if (!has_sha1_file(obj->sha1))
 106                 return;
 107         if (parse_tree(tree) < 0)
 108                 die("bad tree %s", sha1_to_hex(obj->sha1));
 109
 110         init_tree_desc(&desc, tree->buffer, tree->size);
 111         while (tree_entry(&desc, &entry)) {
 112                 switch (object_type(entry.mode)) {
 113                 case OBJ_TREE:
 114                         mark_tree_uninteresting(lookup_tree(entry.sha1));
 115                         break;
 116                 case OBJ_BLOB:
 117                         mark_blob_uninteresting(lookup_blob(entry.sha1));
 118                         break;
 119                 default:
 120                         /* Subproject commit - not in this repository */
 121                         break;
 122                 }
 123         }
 124
 125         /*
 126          * We don't care about the tree any more
 127          * after it has been marked uninteresting.
 128          */
 129         free_tree_buffer(tree);
 130 }
 131
 132 void mark_tree_uninteresting(struct tree *tree)
 133 {
 134         struct object *obj = &tree->object;
 135
 136         if (!tree)
 137                 return;
 138         if (obj->flags & UNINTERESTING)
 139                 return;
 140         obj->flags |= UNINTERESTING;
 141         mark_tree_contents_uninteresting(tree);
 142 }
 143
 144 void mark_parents_uninteresting(struct commit *commit)
 145 {
 146         struct commit_list *parents = NULL, *l;
 147
 148         for (l = commit->parents; l; l = l->next)
 149                 commit_list_insert(l->item, &parents);
 150
 151         while (parents) {
 152                 struct commit *commit = parents->item;
 153                 l = parents;
 154                 parents = parents->next;
 155                 free(l);
 156
 157                 while (commit) {
 158                         /*
 159                          * A missing commit is ok iff its parent is marked
 160                          * uninteresting.
 161                          *
 162                          * We just mark such a thing parsed, so that when
 163                          * it is popped next time around, we won't be trying
 164                          * to parse it and get an error.
 165                          */
 166                         if (!has_sha1_file(commit->object.sha1))
 167                                 commit->object.parsed = 1;
 168
 169                         if (commit->object.flags & UNINTERESTING)
 170                                 break;
 171
 172                         commit->object.flags |= UNINTERESTING;
 173
 174                         /*
 175                          * Normally we haven't parsed the parent
 176                          * yet, so we won't have a parent of a parent
 177                          * here. However, it may turn out that we've
 178                          * reached this commit some other way (where it
 179                          * wasn't uninteresting), in which case we need
 180                          * to mark its parents recursively too..
 181                          */
 182                         if (!commit->parents)
 183                                 break;
 184
 185                         for (l = commit->parents->next; l; l = l->next)
 186                                 commit_list_insert(l->item, &parents);
 187                         commit = commit->parents->item;
 188                 }
 189         }
 190 }
 191
 192 static void add_pending_object_with_path(struct rev_info *revs,
 193                                          struct object *obj,
 194                                          const char *name, unsigned mode,
 195                                          const char *path)
 196 {
 197         if (!obj)
 198                 return;
 199         if (revs->no_walk && (obj->flags & UNINTERESTING))
 200                 revs->no_walk = 0;
 201         if (revs->reflog_info && obj->type == OBJ_COMMIT) {
 202                 struct strbuf buf = STRBUF_INIT;
 203                 int len = interpret_branch_name(name, 0, &buf);
 204                 int st;
 205
 206                 if (0 < len && name[len] && buf.len)
 207                         strbuf_addstr(&buf, name + len);
 208                 st = add_reflog_for_walk(revs->reflog_info,
 209                                          (struct commit *)obj,
 210                                          buf.buf[0] ? buf.buf: name);
 211                 strbuf_release(&buf);
 212                 if (st)
 213                         return;
 214         }
 215         add_object_array_with_path(obj, name, &revs->pending, mode, path);
 216 }
 217
 218 static void add_pending_object_with_mode(struct rev_info *revs,
 219                                          struct object *obj,
 220                                          const char *name, unsigned mode)
 221 {
 222         add_pending_object_with_path(revs, obj, name, mode, NULL);
 223 }
 224
 225 void add_pending_object(struct rev_info *revs,
 226                         struct object *obj, const char *name)
 227 {
 228         add_pending_object_with_mode(revs, obj, name, S_IFINVALID);
 229 }
 230
 231 void add_head_to_pending(struct rev_info *revs)
 232 {
 233         unsigned char sha1[20];
 234         struct object *obj;
 235         if (get_sha1("HEAD", sha1))
 236                 return;
 237         obj = parse_object(sha1);
 238         if (!obj)
 239                 return;
 240         add_pending_object(revs, obj, "HEAD");
 241 }
 242
 243 static struct object *get_reference(struct rev_info *revs, const char *name,
 244                                     const unsigned char *sha1,
 245                                     unsigned int flags)
 246 {
 247         struct object *object;
 248
 249         object = parse_object(sha1);
 250         if (!object) {
 251                 if (revs->ignore_missing)
 252                         return object;
 253                 die("bad object %s", name);
 254         }
 255         object->flags |= flags;
 256         return object;
 257 }
 258
 259 void add_pending_sha1(struct rev_info *revs, const char *name,
 260                       const unsigned char *sha1, unsigned int flags)
 261 {
 262         struct object *object = get_reference(revs, name, sha1, flags);
 263         add_pending_object(revs, object, name);
 264 }
 265
 266 static struct commit *handle_commit(struct rev_info *revs,
 267                                     struct object_array_entry *entry)
 268 {
 269         struct object *object = entry->item;
 270         const char *name = entry->name;
 271         const char *path = entry->path;
 272         unsigned int mode = entry->mode;
 273         unsigned long flags = object->flags;
 274
 275         /*
 276          * Tag object? Look what it points to..
 277          */
 278         while (object->type == OBJ_TAG) {
 279                 struct tag *tag = (struct tag *) object;
 280                 if (revs->tag_objects && !(flags & UNINTERESTING))
 281                         add_pending_object(revs, object, tag->tag);
 282                 if (!tag->tagged)
 283                         die("bad tag");
 284                 object = parse_object(tag->tagged->sha1);
 285                 if (!object) {
 286                         if (flags & UNINTERESTING)
 287                                 return NULL;
 288                         die("bad object %s", sha1_to_hex(tag->tagged->sha1));
 289                 }
 290                 object->flags |= flags;
 291                 /*
 292                  * We'll handle the tagged object by looping or dropping
 293                  * through to the non-tag handlers below. Do not
 294                  * propagate data from the tag's pending entry.
 295                  */
 296                 name = "";
 297                 path = NULL;
 298                 mode = 0;
 299         }
 300
 301         /*
 302          * Commit object? Just return it, we'll do all the complex
 303          * reachability crud.
 304          */
 305         if (object->type == OBJ_COMMIT) {
 306                 struct commit *commit = (struct commit *)object;
 307                 if (parse_commit(commit) < 0)
 308                         die("unable to parse commit %s", name);
 309                 if (flags & UNINTERESTING) {
 310                         mark_parents_uninteresting(commit);
 311                         revs->limited = 1;
 312                 }
 313                 if (revs->show_source && !commit->util)
 314                         commit->util = xstrdup(name);
 315                 return commit;
 316         }
 317
 318         /*
 319          * Tree object? Either mark it uninteresting, or add it
 320          * to the list of objects to look at later..
 321          */
 322         if (object->type == OBJ_TREE) {
 323                 struct tree *tree = (struct tree *)object;
 324                 if (!revs->tree_objects)
 325                         return NULL;
 326                 if (flags & UNINTERESTING) {
 327                         mark_tree_contents_uninteresting(tree);
 328                         return NULL;
 329                 }
 330                 add_pending_object_with_path(revs, object, name, mode, path);
 331                 return NULL;
 332         }
 333
 334         /*
 335          * Blob object? You know the drill by now..
 336          */
 337         if (object->type == OBJ_BLOB) {
 338                 if (!revs->blob_objects)
 339                         return NULL;
 340                 if (flags & UNINTERESTING)
 341                         return NULL;
 342                 add_pending_object_with_path(revs, object, name, mode, path);
 343                 return NULL;
 344         }
 345         die("%s is unknown object", name);
 346 }
 347
 348 static int everybody_uninteresting(struct commit_list *orig,
 349                                    struct commit **interesting_cache)
 350 {
 351         struct commit_list *list = orig;
 352
 353         if (*interesting_cache) {
 354                 struct commit *commit = *interesting_cache;
 355                 if (!(commit->object.flags & UNINTERESTING))
 356                         return 0;
 357         }
 358
 359         while (list) {
 360                 struct commit *commit = list->item;
 361                 list = list->next;
 362                 if (commit->object.flags & UNINTERESTING)
 363                         continue;
 364
 365                 *interesting_cache = commit;
 366                 return 0;
 367         }
 368         return 1;
 369 }
 370
 371 /*
 372  * A definition of "relevant" commit that we can use to simplify limited graphs
 373  * by eliminating side branches.
 374  *
 375  * A "relevant" commit is one that is !UNINTERESTING (ie we are including it
 376  * in our list), or that is a specified BOTTOM commit. Then after computing
 377  * a limited list, during processing we can generally ignore boundary merges
 378  * coming from outside the graph, (ie from irrelevant parents), and treat
 379  * those merges as if they were single-parent. TREESAME is defined to consider
 380  * only relevant parents, if any. If we are TREESAME to our on-graph parents,
 381  * we don't care if we were !TREESAME to non-graph parents.
 382  *
 383  * Treating bottom commits as relevant ensures that a limited graph's
 384  * connection to the actual bottom commit is not viewed as a side branch, but
 385  * treated as part of the graph. For example:
 386  *
 387  *   ....Z...A---X---o---o---B
 388  *        .     /
 389  *         W---Y
 390  *
 391  * When computing "A..B", the A-X connection is at least as important as
 392  * Y-X, despite A being flagged UNINTERESTING.
 393  *
 394  * And when computing --ancestry-path "A..B", the A-X connection is more
 395  * important than Y-X, despite both A and Y being flagged UNINTERESTING.
 396  */
 397 static inline int relevant_commit(struct commit *commit)
 398 {
 399         return (commit->object.flags & (UNINTERESTING | BOTTOM)) != UNINTERESTING;
 400 }
 401
 402 /*
 403  * Return a single relevant commit from a parent list. If we are a TREESAME
 404  * commit, and this selects one of our parents, then we can safely simplify to
 405  * that parent.
 406  */
 407 static struct commit *one_relevant_parent(const struct rev_info *revs,
 408                                           struct commit_list *orig)
 409 {
 410         struct commit_list *list = orig;
 411         struct commit *relevant = NULL;
 412
 413         if (!orig)
 414                 return NULL;
 415
 416         /*
 417          * For 1-parent commits, or if first-parent-only, then return that
 418          * first parent (even if not "relevant" by the above definition).
 419          * TREESAME will have been set purely on that parent.
 420          */
 421         if (revs->first_parent_only || !orig->next)
 422                 return orig->item;
 423
 424         /*
 425          * For multi-parent commits, identify a sole relevant parent, if any.
 426          * If we have only one relevant parent, then TREESAME will be set purely
 427          * with regard to that parent, and we can simplify accordingly.
 428          *
 429          * If we have more than one relevant parent, or no relevant parents
 430          * (and multiple irrelevant ones), then we can't select a parent here
 431          * and return NULL.
 432          */
 433         while (list) {
 434                 struct commit *commit = list->item;
 435                 list = list->next;
 436                 if (relevant_commit(commit)) {
 437                         if (relevant)
 438                                 return NULL;
 439                         relevant = commit;
 440                 }
 441         }
 442         return relevant;
 443 }
 444
 445 /*
 446  * The goal is to get REV_TREE_NEW as the result only if the
 447  * diff consists of all '+' (and no other changes), REV_TREE_OLD
 448  * if the whole diff is removal of old data, and otherwise
 449  * REV_TREE_DIFFERENT (of course if the trees are the same we
 450  * want REV_TREE_SAME).
 451  * That means that once we get to REV_TREE_DIFFERENT, we do not
 452  * have to look any further.
 453  */
 454 static int tree_difference = REV_TREE_SAME;
 455
 456 static void file_add_remove(struct diff_options *options,
 457                     int addremove, unsigned mode,
 458                     const unsigned char *sha1,
 459                     int sha1_valid,
 460                     const char *fullpath, unsigned dirty_submodule)
 461 {
 462         int diff = addremove == '+' ? REV_TREE_NEW : REV_TREE_OLD;
 463
 464         tree_difference |= diff;
 465         if (tree_difference == REV_TREE_DIFFERENT)
 466                 DIFF_OPT_SET(options, HAS_CHANGES);
 467 }
 468
 469 static void file_change(struct diff_options *options,
 470                  unsigned old_mode, unsigned new_mode,
 471                  const unsigned char *old_sha1,
 472                  const unsigned char *new_sha1,
 473                  int old_sha1_valid, int new_sha1_valid,
 474                  const char *fullpath,
 475                  unsigned old_dirty_submodule, unsigned new_dirty_submodule)
 476 {
 477         tree_difference = REV_TREE_DIFFERENT;
 478         DIFF_OPT_SET(options, HAS_CHANGES);
 479 }
 480
 481 static int rev_compare_tree(struct rev_info *revs,
 482                             struct commit *parent, struct commit *commit)
 483 {
 484         struct tree *t1 = parent->tree;
 485         struct tree *t2 = commit->tree;
 486
 487         if (!t1)
 488                 return REV_TREE_NEW;
 489         if (!t2)
 490                 return REV_TREE_OLD;
 491
 492         if (revs->simplify_by_decoration) {
 493                 /*
 494                  * If we are simplifying by decoration, then the commit
 495                  * is worth showing if it has a tag pointing at it.
 496                  */
 497                 if (get_name_decoration(&commit->object))
 498                         return REV_TREE_DIFFERENT;
 499                 /*
 500                  * A commit that is not pointed by a tag is uninteresting
 501                  * if we are not limited by path.  This means that you will
 502                  * see the usual "commits that touch the paths" plus any
 503                  * tagged commit by specifying both --simplify-by-decoration
 504                  * and pathspec.
 505                  */
 506                 if (!revs->prune_data.nr)
 507                         return REV_TREE_SAME;
 508         }
 509
 510         tree_difference = REV_TREE_SAME;
 511         DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
 512         if (diff_tree_sha1(t1->object.sha1, t2->object.sha1, "",
 513                            &revs->pruning) < 0)
 514                 return REV_TREE_DIFFERENT;
 515         return tree_difference;
 516 }
 517
 518 static int rev_same_tree_as_empty(struct rev_info *revs, struct commit *commit)
 519 {
 520         int retval;
 521         struct tree *t1 = commit->tree;
 522
 523         if (!t1)
 524                 return 0;
 525
 526         tree_difference = REV_TREE_SAME;
 527         DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
 528         retval = diff_tree_sha1(NULL, t1->object.sha1, "", &revs->pruning);
 529
 530         return retval >= 0 && (tree_difference == REV_TREE_SAME);
 531 }
 532
 533 struct treesame_state {
 534         unsigned int nparents;
 535         unsigned char treesame[FLEX_ARRAY];
 536 };
 537
 538 static struct treesame_state *initialise_treesame(struct rev_info *revs, struct commit *commit)
 539 {
 540         unsigned n = commit_list_count(commit->parents);
 541         struct treesame_state *st = xcalloc(1, sizeof(*st) + n);
 542         st->nparents = n;
 543         add_decoration(&revs->treesame, &commit->object, st);
 544         return st;
 545 }
 546
 547 /*
 548  * Must be called immediately after removing the nth_parent from a commit's
 549  * parent list, if we are maintaining the per-parent treesame[] decoration.
 550  * This does not recalculate the master TREESAME flag - update_treesame()
 551  * should be called to update it after a sequence of treesame[] modifications
 552  * that may have affected it.
 553  */
 554 static int compact_treesame(struct rev_info *revs, struct commit *commit, unsigned nth_parent)
 555 {
 556         struct treesame_state *st;
 557         int old_same;
 558
 559         if (!commit->parents) {
 560                 /*
 561                  * Have just removed the only parent from a non-merge.
 562                  * Different handling, as we lack decoration.
 563                  */
 564                 if (nth_parent != 0)
 565                         die("compact_treesame %u", nth_parent);
 566                 old_same = !!(commit->object.flags & TREESAME);
 567                 if (rev_same_tree_as_empty(revs, commit))
 568                         commit->object.flags |= TREESAME;
 569                 else
 570                         commit->object.flags &= ~TREESAME;
 571                 return old_same;
 572         }
 573
 574         st = lookup_decoration(&revs->treesame, &commit->object);
 575         if (!st || nth_parent >= st->nparents)
 576                 die("compact_treesame %u", nth_parent);
 577
 578         old_same = st->treesame[nth_parent];
 579         memmove(st->treesame + nth_parent,
 580                 st->treesame + nth_parent + 1,
 581                 st->nparents - nth_parent - 1);
 582
 583         /*
 584          * If we've just become a non-merge commit, update TREESAME
 585          * immediately, and remove the no-longer-needed decoration.
 586          * If still a merge, defer update until update_treesame().
 587          */
 588         if (--st->nparents == 1) {
 589                 if (commit->parents->next)
 590                         die("compact_treesame parents mismatch");
 591                 if (st->treesame[0] && revs->dense)
 592                         commit->object.flags |= TREESAME;
 593                 else
 594                         commit->object.flags &= ~TREESAME;
 595                 free(add_decoration(&revs->treesame, &commit->object, NULL));
 596         }
 597
 598         return old_same;
 599 }
 600
 601 static unsigned update_treesame(struct rev_info *revs, struct commit *commit)
 602 {
 603         if (commit->parents && commit->parents->next) {
 604                 unsigned n;
 605                 struct treesame_state *st;
 606                 struct commit_list *p;
 607                 unsigned relevant_parents;
 608                 unsigned relevant_change, irrelevant_change;
 609
 610                 st = lookup_decoration(&revs->treesame, &commit->object);
 611                 if (!st)
 612                         die("update_treesame %s", sha1_to_hex(commit->object.sha1));
 613                 relevant_parents = 0;
 614                 relevant_change = irrelevant_change = 0;
 615                 for (p = commit->parents, n = 0; p; n++, p = p->next) {
 616                         if (relevant_commit(p->item)) {
 617                                 relevant_change |= !st->treesame[n];
 618                                 relevant_parents++;
 619                         } else
 620                                 irrelevant_change |= !st->treesame[n];
 621                 }
 622                 if (relevant_parents ? relevant_change : irrelevant_change)
 623                         commit->object.flags &= ~TREESAME;
 624                 else
 625                         commit->object.flags |= TREESAME;
 626         }
 627
 628         return commit->object.flags & TREESAME;
 629 }
 630
 631 static inline int limiting_can_increase_treesame(const struct rev_info *revs)
 632 {
 633         /*
 634          * TREESAME is irrelevant unless prune && dense;
 635          * if simplify_history is set, we can't have a mixture of TREESAME and
 636          *    !TREESAME INTERESTING parents (and we don't have treesame[]
 637          *    decoration anyway);
 638          * if first_parent_only is set, then the TREESAME flag is locked
 639          *    against the first parent (and again we lack treesame[] decoration).
 640          */
 641         return revs->prune && revs->dense &&
 642                !revs->simplify_history &&
 643                !revs->first_parent_only;
 644 }
 645
 646 static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
 647 {
 648         struct commit_list **pp, *parent;
 649         struct treesame_state *ts = NULL;
 650         int relevant_change = 0, irrelevant_change = 0;
 651         int relevant_parents, nth_parent;
 652
 653         /*
 654          * If we don't do pruning, everything is interesting
 655          */
 656         if (!revs->prune)
 657                 return;
 658
 659         if (!commit->tree)
 660                 return;
 661
 662         if (!commit->parents) {
 663                 if (rev_same_tree_as_empty(revs, commit))
 664                         commit->object.flags |= TREESAME;
 665                 return;
 666         }
 667
 668         /*
 669          * Normal non-merge commit? If we don't want to make the
 670          * history dense, we consider it always to be a change..
 671          */
 672         if (!revs->dense && !commit->parents->next)
 673                 return;
 674
 675         for (pp = &commit->parents, nth_parent = 0, relevant_parents = 0;
 676              (parent = *pp) != NULL;
 677              pp = &parent->next, nth_parent++) {
 678                 struct commit *p = parent->item;
 679                 if (relevant_commit(p))
 680                         relevant_parents++;
 681
 682                 if (nth_parent == 1) {
 683                         /*
 684                          * This our second loop iteration - so we now know
 685                          * we're dealing with a merge.
 686                          *
 687                          * Do not compare with later parents when we care only about
 688                          * the first parent chain, in order to avoid derailing the
 689                          * traversal to follow a side branch that brought everything
 690                          * in the path we are limited to by the pathspec.
 691                          */
 692                         if (revs->first_parent_only)
 693                                 break;
 694                         /*
 695                          * If this will remain a potentially-simplifiable
 696                          * merge, remember per-parent treesame if needed.
 697                          * Initialise the array with the comparison from our
 698                          * first iteration.
 699                          */
 700                         if (revs->treesame.name &&
 701                             !revs->simplify_history &&
 702                             !(commit->object.flags & UNINTERESTING)) {
 703                                 ts = initialise_treesame(revs, commit);
 704                                 if (!(irrelevant_change || relevant_change))
 705                                         ts->treesame[0] = 1;
 706                         }
 707                 }
 708                 if (parse_commit(p) < 0)
 709                         die("cannot simplify commit %s (because of %s)",
 710                             sha1_to_hex(commit->object.sha1),
 711                             sha1_to_hex(p->object.sha1));
 712                 switch (rev_compare_tree(revs, p, commit)) {
 713                 case REV_TREE_SAME:
 714                         if (!revs->simplify_history || !relevant_commit(p)) {
 715                                 /* Even if a merge with an uninteresting
 716                                  * side branch brought the entire change
 717                                  * we are interested in, we do not want
 718                                  * to lose the other branches of this
 719                                  * merge, so we just keep going.
 720                                  */
 721                                 if (ts)
 722                                         ts->treesame[nth_parent] = 1;
 723                                 continue;
 724                         }
 725                         parent->next = NULL;
 726                         commit->parents = parent;
 727                         commit->object.flags |= TREESAME;
 728                         return;
 729
 730                 case REV_TREE_NEW:
 731                         if (revs->remove_empty_trees &&
 732                             rev_same_tree_as_empty(revs, p)) {
 733                                 /* We are adding all the specified
 734                                  * paths from this parent, so the
 735                                  * history beyond this parent is not
 736                                  * interesting.  Remove its parents
 737                                  * (they are grandparents for us).
 738                                  * IOW, we pretend this parent is a
 739                                  * "root" commit.
 740                                  */
 741                                 if (parse_commit(p) < 0)
 742                                         die("cannot simplify commit %s (invalid %s)",
 743                                             sha1_to_hex(commit->object.sha1),
 744                                             sha1_to_hex(p->object.sha1));
 745                                 p->parents = NULL;
 746                         }
 747                 /* fallthrough */
 748                 case REV_TREE_OLD:
 749                 case REV_TREE_DIFFERENT:
 750                         if (relevant_commit(p))
 751                                 relevant_change = 1;
 752                         else
 753                                 irrelevant_change = 1;
 754                         continue;
 755                 }
 756                 die("bad tree compare for commit %s", sha1_to_hex(commit->object.sha1));
 757         }
 758
 759         /*
 760          * TREESAME is straightforward for single-parent commits. For merge
 761          * commits, it is most useful to define it so that "irrelevant"
 762          * parents cannot make us !TREESAME - if we have any relevant
 763          * parents, then we only consider TREESAMEness with respect to them,
 764          * allowing irrelevant merges from uninteresting branches to be
 765          * simplified away. Only if we have only irrelevant parents do we
 766          * base TREESAME on them. Note that this logic is replicated in
 767          * update_treesame, which should be kept in sync.
 768          */
 769         if (relevant_parents ? !relevant_change : !irrelevant_change)
 770                 commit->object.flags |= TREESAME;
 771 }
 772
 773 static void commit_list_insert_by_date_cached(struct commit *p, struct commit_list **head,
 774                     struct commit_list *cached_base, struct commit_list **cache)
 775 {
 776         struct commit_list *new_entry;
 777
 778         if (cached_base && p->date < cached_base->item->date)
 779                 new_entry = commit_list_insert_by_date(p, &cached_base->next);
 780         else
 781                 new_entry = commit_list_insert_by_date(p, head);
 782
 783         if (cache && (!*cache || p->date < (*cache)->item->date))
 784                 *cache = new_entry;
 785 }
 786
 787 static int add_parents_to_list(struct rev_info *revs, struct commit *commit,
 788                     struct commit_list **list, struct commit_list **cache_ptr)
 789 {
 790         struct commit_list *parent = commit->parents;
 791         unsigned left_flag;
 792         struct commit_list *cached_base = cache_ptr ? *cache_ptr : NULL;
 793
 794         if (commit->object.flags & ADDED)
 795                 return 0;
 796         commit->object.flags |= ADDED;
 797
 798         if (revs->include_check &&
 799             !revs->include_check(commit, revs->include_check_data))
 800                 return 0;
 801
 802         /*
 803          * If the commit is uninteresting, don't try to
 804          * prune parents - we want the maximal uninteresting
 805          * set.
 806          *
 807          * Normally we haven't parsed the parent
 808          * yet, so we won't have a parent of a parent
 809          * here. However, it may turn out that we've
 810          * reached this commit some other way (where it
 811          * wasn't uninteresting), in which case we need
 812          * to mark its parents recursively too..
 813          */
 814         if (commit->object.flags & UNINTERESTING) {
 815                 while (parent) {
 816                         struct commit *p = parent->item;
 817                         parent = parent->next;
 818                         if (p)
 819                                 p->object.flags |= UNINTERESTING;
 820                         if (parse_commit_gently(p, 1) < 0)
 821                                 continue;
 822                         if (p->parents)
 823                                 mark_parents_uninteresting(p);
 824                         if (p->object.flags & SEEN)
 825                                 continue;
 826                         p->object.flags |= SEEN;
 827                         commit_list_insert_by_date_cached(p, list, cached_base, cache_ptr);
 828                 }
 829                 return 0;
 830         }
 831
 832         /*
 833          * Ok, the commit wasn't uninteresting. Try to
 834          * simplify the commit history and find the parent
 835          * that has no differences in the path set if one exists.
 836          */
 837         try_to_simplify_commit(revs, commit);
 838
 839         if (revs->no_walk)
 840                 return 0;
 841
 842         left_flag = (commit->object.flags & SYMMETRIC_LEFT);
 843
 844         for (parent = commit->parents; parent; parent = parent->next) {
 845                 struct commit *p = parent->item;
 846
 847                 if (parse_commit_gently(p, revs->ignore_missing_links) < 0)
 848                         return -1;
 849                 if (revs->show_source && !p->util)
 850                         p->util = commit->util;
 851                 p->object.flags |= left_flag;
 852                 if (!(p->object.flags & SEEN)) {
 853                         p->object.flags |= SEEN;
 854                         commit_list_insert_by_date_cached(p, list, cached_base, cache_ptr);
 855                 }
 856                 if (revs->first_parent_only)
 857                         break;
 858         }
 859         return 0;
 860 }
 861
 862 static void cherry_pick_list(struct commit_list *list, struct rev_info *revs)
 863 {
 864         struct commit_list *p;
 865         int left_count = 0, right_count = 0;
 866         int left_first;
 867         struct patch_ids ids;
 868         unsigned cherry_flag;
 869
 870         /* First count the commits on the left and on the right */
 871         for (p = list; p; p = p->next) {
 872                 struct commit *commit = p->item;
 873                 unsigned flags = commit->object.flags;
 874                 if (flags & BOUNDARY)
 875                         ;
 876                 else if (flags & SYMMETRIC_LEFT)
 877                         left_count++;
 878                 else
 879                         right_count++;
 880         }
 881
 882         if (!left_count || !right_count)
 883                 return;
 884
 885         left_first = left_count < right_count;
 886         init_patch_ids(&ids);
 887         ids.diffopts.pathspec = revs->diffopt.pathspec;
 888
 889         /* Compute patch-ids for one side */
 890         for (p = list; p; p = p->next) {
 891                 struct commit *commit = p->item;
 892                 unsigned flags = commit->object.flags;
 893
 894                 if (flags & BOUNDARY)
 895                         continue;
 896                 /*
 897                  * If we have fewer left, left_first is set and we omit
 898                  * commits on the right branch in this loop.  If we have
 899                  * fewer right, we skip the left ones.
 900                  */
 901                 if (left_first != !!(flags & SYMMETRIC_LEFT))
 902                         continue;
 903                 commit->util = add_commit_patch_id(commit, &ids);
 904         }
 905
 906         /* either cherry_mark or cherry_pick are true */
 907         cherry_flag = revs->cherry_mark ? PATCHSAME : SHOWN;
 908
 909         /* Check the other side */
 910         for (p = list; p; p = p->next) {
 911                 struct commit *commit = p->item;
 912                 struct patch_id *id;
 913                 unsigned flags = commit->object.flags;
 914
 915                 if (flags & BOUNDARY)
 916                         continue;
 917                 /*
 918                  * If we have fewer left, left_first is set and we omit
 919                  * commits on the left branch in this loop.
 920                  */
 921                 if (left_first == !!(flags & SYMMETRIC_LEFT))
 922                         continue;
 923
 924                 /*
 925                  * Have we seen the same patch id?
 926                  */
 927                 id = has_commit_patch_id(commit, &ids);
 928                 if (!id)
 929                         continue;
 930                 id->seen = 1;
 931                 commit->object.flags |= cherry_flag;
 932         }
 933
 934         /* Now check the original side for seen ones */
 935         for (p = list; p; p = p->next) {
 936                 struct commit *commit = p->item;
 937                 struct patch_id *ent;
 938
 939                 ent = commit->util;
 940                 if (!ent)
 941                         continue;
 942                 if (ent->seen)
 943                         commit->object.flags |= cherry_flag;
 944                 commit->util = NULL;
 945         }
 946
 947         free_patch_ids(&ids);
 948 }
 949
 950 /* How many extra uninteresting commits we want to see.. */
 951 #define SLOP 5
 952
 953 static int still_interesting(struct commit_list *src, unsigned long date, int slop,
 954                              struct commit **interesting_cache)
 955 {
 956         /*
 957          * No source list at all? We're definitely done..
 958          */
 959         if (!src)
 960                 return 0;
 961
 962         /*
 963          * Does the destination list contain entries with a date
 964          * before the source list? Definitely _not_ done.
 965          */
 966         if (date <= src->item->date)
 967                 return SLOP;
 968
 969         /*
 970          * Does the source list still have interesting commits in
 971          * it? Definitely not done..
 972          */
 973         if (!everybody_uninteresting(src, interesting_cache))
 974                 return SLOP;
 975
 976         /* Ok, we're closing in.. */
 977         return slop-1;
 978 }
 979
 980 /*
 981  * "rev-list --ancestry-path A..B" computes commits that are ancestors
 982  * of B but not ancestors of A but further limits the result to those
 983  * that are descendants of A.  This takes the list of bottom commits and
 984  * the result of "A..B" without --ancestry-path, and limits the latter
 985  * further to the ones that can reach one of the commits in "bottom".
 986  */
 987 static void limit_to_ancestry(struct commit_list *bottom, struct commit_list *list)
 988 {
 989         struct commit_list *p;
 990         struct commit_list *rlist = NULL;
 991         int made_progress;
 992
 993         /*
 994          * Reverse the list so that it will be likely that we would
 995          * process parents before children.
 996          */
 997         for (p = list; p; p = p->next)
 998                 commit_list_insert(p->item, &rlist);
 999
1000         for (p = bottom; p; p = p->next)
1001                 p->item->object.flags |= TMP_MARK;
1002
1003         /*
1004          * Mark the ones that can reach bottom commits in "list",
1005          * in a bottom-up fashion.
1006          */
1007         do {
1008                 made_progress = 0;
1009                 for (p = rlist; p; p = p->next) {
1010                         struct commit *c = p->item;
1011                         struct commit_list *parents;
1012                         if (c->object.flags & (TMP_MARK | UNINTERESTING))
1013                                 continue;
1014                         for (parents = c->parents;
1015                              parents;
1016                              parents = parents->next) {
1017                                 if (!(parents->item->object.flags & TMP_MARK))
1018                                         continue;
1019                                 c->object.flags |= TMP_MARK;
1020                                 made_progress = 1;
1021                                 break;
1022                         }
1023                 }
1024         } while (made_progress);
1025
1026         /*
1027          * NEEDSWORK: decide if we want to remove parents that are
1028          * not marked with TMP_MARK from commit->parents for commits
1029          * in the resulting list.  We may not want to do that, though.
1030          */
1031
1032         /*
1033          * The ones that are not marked with TMP_MARK are uninteresting
1034          */
1035         for (p = list; p; p = p->next) {
1036                 struct commit *c = p->item;
1037                 if (c->object.flags & TMP_MARK)
1038                         continue;
1039                 c->object.flags |= UNINTERESTING;
1040         }
1041
1042         /* We are done with the TMP_MARK */
1043         for (p = list; p; p = p->next)
1044                 p->item->object.flags &= ~TMP_MARK;
1045         for (p = bottom; p; p = p->next)
1046                 p->item->object.flags &= ~TMP_MARK;
1047         free_commit_list(rlist);
1048 }
1049
1050 /*
1051  * Before walking the history, keep the set of "negative" refs the
1052  * caller has asked to exclude.
1053  *
1054  * This is used to compute "rev-list --ancestry-path A..B", as we need
1055  * to filter the result of "A..B" further to the ones that can actually
1056  * reach A.
1057  */
1058 static struct commit_list *collect_bottom_commits(struct commit_list *list)
1059 {
1060         struct commit_list *elem, *bottom = NULL;
1061         for (elem = list; elem; elem = elem->next)
1062                 if (elem->item->object.flags & BOTTOM)
1063                         commit_list_insert(elem->item, &bottom);
1064         return bottom;
1065 }
1066
1067 /* Assumes either left_only or right_only is set */
1068 static void limit_left_right(struct commit_list *list, struct rev_info *revs)
1069 {
1070         struct commit_list *p;
1071
1072         for (p = list; p; p = p->next) {
1073                 struct commit *commit = p->item;
1074
1075                 if (revs->right_only) {
1076                         if (commit->object.flags & SYMMETRIC_LEFT)
1077                                 commit->object.flags |= SHOWN;
1078                 } else  /* revs->left_only is set */
1079                         if (!(commit->object.flags & SYMMETRIC_LEFT))
1080                                 commit->object.flags |= SHOWN;
1081         }
1082 }
1083
1084 static int limit_list(struct rev_info *revs)
1085 {
1086         int slop = SLOP;
1087         unsigned long date = ~0ul;
1088         struct commit_list *list = revs->commits;
1089         struct commit_list *newlist = NULL;
1090         struct commit_list **p = &newlist;
1091         struct commit_list *bottom = NULL;
1092         struct commit *interesting_cache = NULL;
1093
1094         if (revs->ancestry_path) {
1095                 bottom = collect_bottom_commits(list);
1096                 if (!bottom)
1097                         die("--ancestry-path given but there are no bottom commits");
1098         }
1099
1100         while (list) {
1101                 struct commit_list *entry = list;
1102                 struct commit *commit = list->item;
1103                 struct object *obj = &commit->object;
1104                 show_early_output_fn_t show;
1105
1106                 list = list->next;
1107                 free(entry);
1108
1109                 if (commit == interesting_cache)
1110                         interesting_cache = NULL;
1111
1112                 if (revs->max_age != -1 && (commit->date < revs->max_age))
1113                         obj->flags |= UNINTERESTING;
1114                 if (add_parents_to_list(revs, commit, &list, NULL) < 0)
1115                         return -1;
1116                 if (obj->flags & UNINTERESTING) {
1117                         mark_parents_uninteresting(commit);
1118                         if (revs->show_all)
1119                                 p = &commit_list_insert(commit, p)->next;
1120                         slop = still_interesting(list, date, slop, &interesting_cache);
1121                         if (slop)
1122                                 continue;
1123                         /* If showing all, add the whole pending list to the end */
1124                         if (revs->show_all)
1125                                 *p = list;
1126                         break;
1127                 }
1128                 if (revs->min_age != -1 && (commit->date > revs->min_age))
1129                         continue;
1130                 date = commit->date;
1131                 p = &commit_list_insert(commit, p)->next;
1132
1133                 show = show_early_output;
1134                 if (!show)
1135                         continue;
1136
1137                 show(revs, newlist);
1138                 show_early_output = NULL;
1139         }
1140         if (revs->cherry_pick || revs->cherry_mark)
1141                 cherry_pick_list(newlist, revs);
1142
1143         if (revs->left_only || revs->right_only)
1144                 limit_left_right(newlist, revs);
1145
1146         if (bottom) {
1147                 limit_to_ancestry(bottom, newlist);
1148                 free_commit_list(bottom);
1149         }
1150
1151         /*
1152          * Check if any commits have become TREESAME by some of their parents
1153          * becoming UNINTERESTING.
1154          */
1155         if (limiting_can_increase_treesame(revs))
1156                 for (list = newlist; list; list = list->next) {
1157                         struct commit *c = list->item;
1158                         if (c->object.flags & (UNINTERESTING | TREESAME))
1159                                 continue;
1160                         update_treesame(revs, c);
1161                 }
1162
1163         revs->commits = newlist;
1164         return 0;
1165 }
1166
1167 /*
1168  * Add an entry to refs->cmdline with the specified information.
1169  * *name is copied.
1170  */
1171 static void add_rev_cmdline(struct rev_info *revs,
1172                             struct object *item,
1173                             const char *name,
1174                             int whence,
1175                             unsigned flags)
1176 {
1177         struct rev_cmdline_info *info = &revs->cmdline;
1178         int nr = info->nr;
1179
1180         ALLOC_GROW(info->rev, nr + 1, info->alloc);
1181         info->rev[nr].item = item;
1182         info->rev[nr].name = xstrdup(name);
1183         info->rev[nr].whence = whence;
1184         info->rev[nr].flags = flags;
1185         info->nr++;
1186 }
1187
1188 static void add_rev_cmdline_list(struct rev_info *revs,
1189                                  struct commit_list *commit_list,
1190                                  int whence,
1191                                  unsigned flags)
1192 {
1193         while (commit_list) {
1194                 struct object *object = &commit_list->item->object;
1195                 add_rev_cmdline(revs, object, sha1_to_hex(object->sha1),
1196                                 whence, flags);
1197                 commit_list = commit_list->next;
1198         }
1199 }
1200
1201 struct all_refs_cb {
1202         int all_flags;
1203         int warned_bad_reflog;
1204         struct rev_info *all_revs;
1205         const char *name_for_errormsg;
1206 };
1207
1208 int ref_excluded(struct string_list *ref_excludes, const char *path)
1209 {
1210         struct string_list_item *item;
1211
1212         if (!ref_excludes)
1213                 return 0;
1214         for_each_string_list_item(item, ref_excludes) {
1215                 if (!wildmatch(item->string, path, 0, NULL))
1216                         return 1;
1217         }
1218         return 0;
1219 }
1220
1221 static int handle_one_ref(const char *path, const struct object_id *oid,
1222                           int flag, void *cb_data)
1223 {
1224         struct all_refs_cb *cb = cb_data;
1225         struct object *object;
1226
1227         if (ref_excluded(cb->all_revs->ref_excludes, path))
1228             return 0;
1229
1230         object = get_reference(cb->all_revs, path, oid->hash, cb->all_flags);
1231         add_rev_cmdline(cb->all_revs, object, path, REV_CMD_REF, cb->all_flags);
1232         add_pending_sha1(cb->all_revs, path, oid->hash, cb->all_flags);
1233         return 0;
1234 }
1235
1236 static void init_all_refs_cb(struct all_refs_cb *cb, struct rev_info *revs,
1237         unsigned flags)
1238 {
1239         cb->all_revs = revs;
1240         cb->all_flags = flags;
1241 }
1242
1243 void clear_ref_exclusion(struct string_list **ref_excludes_p)
1244 {
1245         if (*ref_excludes_p) {
1246                 string_list_clear(*ref_excludes_p, 0);
1247                 free(*ref_excludes_p);
1248         }
1249         *ref_excludes_p = NULL;
1250 }
1251
1252 void add_ref_exclusion(struct string_list **ref_excludes_p, const char *exclude)
1253 {
1254         if (!*ref_excludes_p) {
1255                 *ref_excludes_p = xcalloc(1, sizeof(**ref_excludes_p));
1256                 (*ref_excludes_p)->strdup_strings = 1;
1257         }
1258         string_list_append(*ref_excludes_p, exclude);
1259 }
1260
1261 static void handle_refs(const char *submodule, struct rev_info *revs, unsigned flags,
1262                 int (*for_each)(const char *, each_ref_fn, void *))
1263 {
1264         struct all_refs_cb cb;
1265         init_all_refs_cb(&cb, revs, flags);
1266         for_each(submodule, handle_one_ref, &cb);
1267 }
1268
1269 static void handle_one_reflog_commit(unsigned char *sha1, void *cb_data)
1270 {
1271         struct all_refs_cb *cb = cb_data;
1272         if (!is_null_sha1(sha1)) {
1273                 struct object *o = parse_object(sha1);
1274                 if (o) {
1275                         o->flags |= cb->all_flags;
1276                         /* ??? CMDLINEFLAGS ??? */
1277                         add_pending_object(cb->all_revs, o, "");
1278                 }
1279                 else if (!cb->warned_bad_reflog) {
1280                         warning("reflog of '%s' references pruned commits",
1281                                 cb->name_for_errormsg);
1282                         cb->warned_bad_reflog = 1;
1283                 }
1284         }
1285 }
1286
1287 static int handle_one_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
1288                 const char *email, unsigned long timestamp, int tz,
1289                 const char *message, void *cb_data)
1290 {
1291         handle_one_reflog_commit(osha1, cb_data);
1292         handle_one_reflog_commit(nsha1, cb_data);
1293         return 0;
1294 }
1295
1296 static int handle_one_reflog(const char *path, const struct object_id *oid,
1297                              int flag, void *cb_data)
1298 {
1299         struct all_refs_cb *cb = cb_data;
1300         cb->warned_bad_reflog = 0;
1301         cb->name_for_errormsg = path;
1302         for_each_reflog_ent(path, handle_one_reflog_ent, cb_data);
1303         return 0;
1304 }
1305
1306 void add_reflogs_to_pending(struct rev_info *revs, unsigned flags)
1307 {
1308         struct all_refs_cb cb;
1309
1310         cb.all_revs = revs;
1311         cb.all_flags = flags;
1312         for_each_reflog(handle_one_reflog, &cb);
1313 }
1314
1315 static void add_cache_tree(struct cache_tree *it, struct rev_info *revs,
1316                            struct strbuf *path)
1317 {
1318         size_t baselen = path->len;
1319         int i;
1320
1321         if (it->entry_count >= 0) {
1322                 struct tree *tree = lookup_tree(it->sha1);
1323                 add_pending_object_with_path(revs, &tree->object, "",
1324                                              040000, path->buf);
1325         }
1326
1327         for (i = 0; i < it->subtree_nr; i++) {
1328                 struct cache_tree_sub *sub = it->down[i];
1329                 strbuf_addf(path, "%s%s", baselen ? "/" : "", sub->name);
1330                 add_cache_tree(sub->cache_tree, revs, path);
1331                 strbuf_setlen(path, baselen);
1332         }
1333
1334 }
1335
1336 void add_index_objects_to_pending(struct rev_info *revs, unsigned flags)
1337 {
1338         int i;
1339
1340         read_cache();
1341         for (i = 0; i < active_nr; i++) {
1342                 struct cache_entry *ce = active_cache[i];
1343                 struct blob *blob;
1344
1345                 if (S_ISGITLINK(ce->ce_mode))
1346                         continue;
1347
1348                 blob = lookup_blob(ce->sha1);
1349                 if (!blob)
1350                         die("unable to add index blob to traversal");
1351                 add_pending_object_with_path(revs, &blob->object, "",
1352                                              ce->ce_mode, ce->name);
1353         }
1354
1355         if (active_cache_tree) {
1356                 struct strbuf path = STRBUF_INIT;
1357                 add_cache_tree(active_cache_tree, revs, &path);
1358                 strbuf_release(&path);
1359         }
1360 }
1361
1362 static int add_parents_only(struct rev_info *revs, const char *arg_, int flags)
1363 {
1364         unsigned char sha1[20];
1365         struct object *it;
1366         struct commit *commit;
1367         struct commit_list *parents;
1368         const char *arg = arg_;
1369
1370         if (*arg == '^') {
1371                 flags ^= UNINTERESTING | BOTTOM;
1372                 arg++;
1373         }
1374         if (get_sha1_committish(arg, sha1))
1375                 return 0;
1376         while (1) {
1377                 it = get_reference(revs, arg, sha1, 0);
1378                 if (!it && revs->ignore_missing)
1379                         return 0;
1380                 if (it->type != OBJ_TAG)
1381                         break;
1382                 if (!((struct tag*)it)->tagged)
1383                         return 0;
1384                 hashcpy(sha1, ((struct tag*)it)->tagged->sha1);
1385         }
1386         if (it->type != OBJ_COMMIT)
1387                 return 0;
1388         commit = (struct commit *)it;
1389         for (parents = commit->parents; parents; parents = parents->next) {
1390                 it = &parents->item->object;
1391                 it->flags |= flags;
1392                 add_rev_cmdline(revs, it, arg_, REV_CMD_PARENTS_ONLY, flags);
1393                 add_pending_object(revs, it, arg);
1394         }
1395         return 1;
1396 }
1397
1398 void init_revisions(struct rev_info *revs, const char *prefix)
1399 {
1400         memset(revs, 0, sizeof(*revs));
1401
1402         revs->abbrev = DEFAULT_ABBREV;
1403         revs->ignore_merges = 1;
1404         revs->simplify_history = 1;
1405         DIFF_OPT_SET(&revs->pruning, RECURSIVE);
1406         DIFF_OPT_SET(&revs->pruning, QUICK);
1407         revs->pruning.add_remove = file_add_remove;
1408         revs->pruning.change = file_change;
1409         revs->sort_order = REV_SORT_IN_GRAPH_ORDER;
1410         revs->dense = 1;
1411         revs->prefix = prefix;
1412         revs->max_age = -1;
1413         revs->min_age = -1;
1414         revs->skip_count = -1;
1415         revs->max_count = -1;
1416         revs->max_parents = -1;
1417
1418         revs->commit_format = CMIT_FMT_DEFAULT;
1419
1420         init_grep_defaults();
1421         grep_init(&revs->grep_filter, prefix);
1422         revs->grep_filter.status_only = 1;
1423         revs->grep_filter.regflags = REG_NEWLINE;
1424
1425         diff_setup(&revs->diffopt);
1426         if (prefix && !revs->diffopt.prefix) {
1427                 revs->diffopt.prefix = prefix;
1428                 revs->diffopt.prefix_length = strlen(prefix);
1429         }
1430
1431         revs->notes_opt.use_default_notes = -1;
1432 }
1433
1434 static void add_pending_commit_list(struct rev_info *revs,
1435                                     struct commit_list *commit_list,
1436                                     unsigned int flags)
1437 {
1438         while (commit_list) {
1439                 struct object *object = &commit_list->item->object;
1440                 object->flags |= flags;
1441                 add_pending_object(revs, object, sha1_to_hex(object->sha1));
1442                 commit_list = commit_list->next;
1443         }
1444 }
1445
1446 static void prepare_show_merge(struct rev_info *revs)
1447 {
1448         struct commit_list *bases;
1449         struct commit *head, *other;
1450         unsigned char sha1[20];
1451         const char **prune = NULL;
1452         int i, prune_num = 1; /* counting terminating NULL */
1453
1454         if (get_sha1("HEAD", sha1))
1455                 die("--merge without HEAD?");
1456         head = lookup_commit_or_die(sha1, "HEAD");
1457         if (get_sha1("MERGE_HEAD", sha1))
1458                 die("--merge without MERGE_HEAD?");
1459         other = lookup_commit_or_die(sha1, "MERGE_HEAD");
1460         add_pending_object(revs, &head->object, "HEAD");
1461         add_pending_object(revs, &other->object, "MERGE_HEAD");
1462         bases = get_merge_bases(head, other);
1463         add_rev_cmdline_list(revs, bases, REV_CMD_MERGE_BASE, UNINTERESTING | BOTTOM);
1464         add_pending_commit_list(revs, bases, UNINTERESTING | BOTTOM);
1465         free_commit_list(bases);
1466         head->object.flags |= SYMMETRIC_LEFT;
1467
1468         if (!active_nr)
1469                 read_cache();
1470         for (i = 0; i < active_nr; i++) {
1471                 const struct cache_entry *ce = active_cache[i];
1472                 if (!ce_stage(ce))
1473                         continue;
1474                 if (ce_path_match(ce, &revs->prune_data, NULL)) {
1475                         prune_num++;
1476                         REALLOC_ARRAY(prune, prune_num);
1477                         prune[prune_num-2] = ce->name;
1478                         prune[prune_num-1] = NULL;
1479                 }
1480                 while ((i+1 < active_nr) &&
1481                        ce_same_name(ce, active_cache[i+1]))
1482                         i++;
1483         }
1484         free_pathspec(&revs->prune_data);
1485         parse_pathspec(&revs->prune_data, PATHSPEC_ALL_MAGIC & ~PATHSPEC_LITERAL,
1486                        PATHSPEC_PREFER_FULL | PATHSPEC_LITERAL_PATH, "", prune);
1487         revs->limited = 1;
1488 }
1489
1490 int handle_revision_arg(const char *arg_, struct rev_info *revs, int flags, unsigned revarg_opt)
1491 {
1492         struct object_context oc;
1493         char *dotdot;
1494         struct object *object;
1495         unsigned char sha1[20];
1496         int local_flags;
1497         const char *arg = arg_;
1498         int cant_be_filename = revarg_opt & REVARG_CANNOT_BE_FILENAME;
1499         unsigned get_sha1_flags = 0;
1500
1501         flags = flags & UNINTERESTING ? flags | BOTTOM : flags & ~BOTTOM;
1502
1503         dotdot = strstr(arg, "..");
1504         if (dotdot) {
1505                 unsigned char from_sha1[20];
1506                 const char *next = dotdot + 2;
1507                 const char *this = arg;
1508                 int symmetric = *next == '.';
1509                 unsigned int flags_exclude = flags ^ (UNINTERESTING | BOTTOM);
1510                 static const char head_by_default[] = "HEAD";
1511                 unsigned int a_flags;
1512
1513                 *dotdot = 0;
1514                 next += symmetric;
1515
1516                 if (!*next)
1517                         next = head_by_default;
1518                 if (dotdot == arg)
1519                         this = head_by_default;
1520                 if (this == head_by_default && next == head_by_default &&
1521                     !symmetric) {
1522                         /*
1523                          * Just ".."?  That is not a range but the
1524                          * pathspec for the parent directory.
1525                          */
1526                         if (!cant_be_filename) {
1527                                 *dotdot = '.';
1528                                 return -1;
1529                         }
1530                 }
1531                 if (!get_sha1_committish(this, from_sha1) &&
1532                     !get_sha1_committish(next, sha1)) {
1533                         struct object *a_obj, *b_obj;
1534
1535                         if (!cant_be_filename) {
1536                                 *dotdot = '.';
1537                                 verify_non_filename(revs->prefix, arg);
1538                         }
1539
1540                         a_obj = parse_object(from_sha1);
1541                         b_obj = parse_object(sha1);
1542                         if (!a_obj || !b_obj) {
1543                         missing:
1544                                 if (revs->ignore_missing)
1545                                         return 0;
1546                                 die(symmetric
1547                                     ? "Invalid symmetric difference expression %s"
1548                                     : "Invalid revision range %s", arg);
1549                         }
1550
1551                         if (!symmetric) {
1552                                 /* just A..B */
1553                                 a_flags = flags_exclude;
1554                         } else {
1555                                 /* A...B -- find merge bases between the two */
1556                                 struct commit *a, *b;
1557                                 struct commit_list *exclude;
1558
1559                                 a = (a_obj->type == OBJ_COMMIT
1560                                      ? (struct commit *)a_obj
1561                                      : lookup_commit_reference(a_obj->sha1));
1562                                 b = (b_obj->type == OBJ_COMMIT
1563                                      ? (struct commit *)b_obj
1564                                      : lookup_commit_reference(b_obj->sha1));
1565                                 if (!a || !b)
1566                                         goto missing;
1567                                 exclude = get_merge_bases(a, b);
1568                                 add_rev_cmdline_list(revs, exclude,
1569                                                      REV_CMD_MERGE_BASE,
1570                                                      flags_exclude);
1571                                 add_pending_commit_list(revs, exclude,
1572                                                         flags_exclude);
1573                                 free_commit_list(exclude);
1574
1575                                 a_flags = flags | SYMMETRIC_LEFT;
1576                         }
1577
1578                         a_obj->flags |= a_flags;
1579                         b_obj->flags |= flags;
1580                         add_rev_cmdline(revs, a_obj, this,
1581                                         REV_CMD_LEFT, a_flags);
1582                         add_rev_cmdline(revs, b_obj, next,
1583                                         REV_CMD_RIGHT, flags);
1584                         add_pending_object(revs, a_obj, this);
1585                         add_pending_object(revs, b_obj, next);
1586                         return 0;
1587                 }
1588                 *dotdot = '.';
1589         }
1590         dotdot = strstr(arg, "^@");
1591         if (dotdot && !dotdot[2]) {
1592                 *dotdot = 0;
1593                 if (add_parents_only(revs, arg, flags))
1594                         return 0;
1595                 *dotdot = '^';
1596         }
1597         dotdot = strstr(arg, "^!");
1598         if (dotdot && !dotdot[2]) {
1599                 *dotdot = 0;
1600                 if (!add_parents_only(revs, arg, flags ^ (UNINTERESTING | BOTTOM)))
1601                         *dotdot = '^';
1602         }
1603
1604         local_flags = 0;
1605         if (*arg == '^') {
1606                 local_flags = UNINTERESTING | BOTTOM;
1607                 arg++;
1608         }
1609
1610         if (revarg_opt & REVARG_COMMITTISH)
1611                 get_sha1_flags = GET_SHA1_COMMITTISH;
1612
1613         if (get_sha1_with_context(arg, get_sha1_flags, sha1, &oc))
1614                 return revs->ignore_missing ? 0 : -1;
1615         if (!cant_be_filename)
1616                 verify_non_filename(revs->prefix, arg);
1617         object = get_reference(revs, arg, sha1, flags ^ local_flags);
1618         add_rev_cmdline(revs, object, arg_, REV_CMD_REV, flags ^ local_flags);
1619         add_pending_object_with_mode(revs, object, arg, oc.mode);
1620         return 0;
1621 }
1622
1623 struct cmdline_pathspec {
1624         int alloc;
1625         int nr;
1626         const char **path;
1627 };
1628
1629 static void append_prune_data(struct cmdline_pathspec *prune, const char **av)
1630 {
1631         while (*av) {
1632                 ALLOC_GROW(prune->path, prune->nr + 1, prune->alloc);
1633                 prune->path[prune->nr++] = *(av++);
1634         }
1635 }
1636
1637 static void read_pathspec_from_stdin(struct rev_info *revs, struct strbuf *sb,
1638                                      struct cmdline_pathspec *prune)
1639 {
1640         while (strbuf_getwholeline(sb, stdin, '\n') != EOF) {
1641                 int len = sb->len;
1642                 if (len && sb->buf[len - 1] == '\n')
1643                         sb->buf[--len] = '\0';
1644                 ALLOC_GROW(prune->path, prune->nr + 1, prune->alloc);
1645                 prune->path[prune->nr++] = xstrdup(sb->buf);
1646         }
1647 }
1648
1649 static void read_revisions_from_stdin(struct rev_info *revs,
1650                                       struct cmdline_pathspec *prune)
1651 {
1652         struct strbuf sb;
1653         int seen_dashdash = 0;
1654         int save_warning;
1655
1656         save_warning = warn_on_object_refname_ambiguity;
1657         warn_on_object_refname_ambiguity = 0;
1658
1659         strbuf_init(&sb, 1000);
1660         while (strbuf_getwholeline(&sb, stdin, '\n') != EOF) {
1661                 int len = sb.len;
1662                 if (len && sb.buf[len - 1] == '\n')
1663                         sb.buf[--len] = '\0';
1664                 if (!len)
1665                         break;
1666                 if (sb.buf[0] == '-') {
1667                         if (len == 2 && sb.buf[1] == '-') {
1668                                 seen_dashdash = 1;
1669                                 break;
1670                         }
1671                         die("options not supported in --stdin mode");
1672                 }
1673                 if (handle_revision_arg(sb.buf, revs, 0,
1674                                         REVARG_CANNOT_BE_FILENAME))
1675                         die("bad revision '%s'", sb.buf);
1676         }
1677         if (seen_dashdash)
1678                 read_pathspec_from_stdin(revs, &sb, prune);
1679
1680         strbuf_release(&sb);
1681         warn_on_object_refname_ambiguity = save_warning;
1682 }
1683
1684 static void add_grep(struct rev_info *revs, const char *ptn, enum grep_pat_token what)
1685 {
1686         append_grep_pattern(&revs->grep_filter, ptn, "command line", 0, what);
1687 }
1688
1689 static void add_header_grep(struct rev_info *revs, enum grep_header_field field, const char *pattern)
1690 {
1691         append_header_grep_pattern(&revs->grep_filter, field, pattern);
1692 }
1693
1694 static void add_message_grep(struct rev_info *revs, const char *pattern)
1695 {
1696         add_grep(revs, pattern, GREP_PATTERN_BODY);
1697 }
1698
1699 static int handle_revision_opt(struct rev_info *revs, int argc, const char **argv,
1700                                int *unkc, const char **unkv)
1701 {
1702         const char *arg = argv[0];
1703         const char *optarg;
1704         int argcount;
1705
1706         /* pseudo revision arguments */
1707         if (!strcmp(arg, "--all") || !strcmp(arg, "--branches") ||
1708             !strcmp(arg, "--tags") || !strcmp(arg, "--remotes") ||
1709             !strcmp(arg, "--reflog") || !strcmp(arg, "--not") ||
1710             !strcmp(arg, "--no-walk") || !strcmp(arg, "--do-walk") ||
1711             !strcmp(arg, "--bisect") || starts_with(arg, "--glob=") ||
1712             !strcmp(arg, "--indexed-objects") ||
1713             starts_with(arg, "--exclude=") ||
1714             starts_with(arg, "--branches=") || starts_with(arg, "--tags=") ||
1715             starts_with(arg, "--remotes=") || starts_with(arg, "--no-walk="))
1716         {
1717                 unkv[(*unkc)++] = arg;
1718                 return 1;
1719         }
1720
1721         if ((argcount = parse_long_opt("max-count", argv, &optarg))) {
1722                 revs->max_count = atoi(optarg);
1723                 revs->no_walk = 0;
1724                 return argcount;
1725         } else if ((argcount = parse_long_opt("skip", argv, &optarg))) {
1726                 revs->skip_count = atoi(optarg);
1727                 return argcount;
1728         } else if ((*arg == '-') && isdigit(arg[1])) {
1729                 /* accept -<digit>, like traditional "head" */
1730                 if (strtol_i(arg + 1, 10, &revs->max_count) < 0 ||
1731                     revs->max_count < 0)
1732                         die("'%s': not a non-negative integer", arg + 1);
1733                 revs->no_walk = 0;
1734         } else if (!strcmp(arg, "-n")) {
1735                 if (argc <= 1)
1736                         return error("-n requires an argument");
1737                 revs->max_count = atoi(argv[1]);
1738                 revs->no_walk = 0;
1739                 return 2;
1740         } else if (starts_with(arg, "-n")) {
1741                 revs->max_count = atoi(arg + 2);
1742                 revs->no_walk = 0;
1743         } else if ((argcount = parse_long_opt("max-age", argv, &optarg))) {
1744                 revs->max_age = atoi(optarg);
1745                 return argcount;
1746         } else if ((argcount = parse_long_opt("since", argv, &optarg))) {
1747                 revs->max_age = approxidate(optarg);
1748                 return argcount;
1749         } else if ((argcount = parse_long_opt("after", argv, &optarg))) {
1750                 revs->max_age = approxidate(optarg);
1751                 return argcount;
1752         } else if ((argcount = parse_long_opt("min-age", argv, &optarg))) {
1753                 revs->min_age = atoi(optarg);
1754                 return argcount;
1755         } else if ((argcount = parse_long_opt("before", argv, &optarg))) {
1756                 revs->min_age = approxidate(optarg);
1757                 return argcount;
1758         } else if ((argcount = parse_long_opt("until", argv, &optarg))) {
1759                 revs->min_age = approxidate(optarg);
1760                 return argcount;
1761         } else if (!strcmp(arg, "--first-parent")) {
1762                 revs->first_parent_only = 1;
1763         } else if (!strcmp(arg, "--ancestry-path")) {
1764                 revs->ancestry_path = 1;
1765                 revs->simplify_history = 0;
1766                 revs->limited = 1;
1767         } else if (!strcmp(arg, "-g") || !strcmp(arg, "--walk-reflogs")) {
1768                 init_reflog_walk(&revs->reflog_info);
1769         } else if (!strcmp(arg, "--default")) {
1770                 if (argc <= 1)
1771                         return error("bad --default argument");
1772                 revs->def = argv[1];
1773                 return 2;
1774         } else if (!strcmp(arg, "--merge")) {
1775                 revs->show_merge = 1;
1776         } else if (!strcmp(arg, "--topo-order")) {
1777                 revs->sort_order = REV_SORT_IN_GRAPH_ORDER;
1778                 revs->topo_order = 1;
1779         } else if (!strcmp(arg, "--simplify-merges")) {
1780                 revs->simplify_merges = 1;
1781                 revs->topo_order = 1;
1782                 revs->rewrite_parents = 1;
1783                 revs->simplify_history = 0;
1784                 revs->limited = 1;
1785         } else if (!strcmp(arg, "--simplify-by-decoration")) {
1786                 revs->simplify_merges = 1;
1787                 revs->topo_order = 1;
1788                 revs->rewrite_parents = 1;
1789                 revs->simplify_history = 0;
1790                 revs->simplify_by_decoration = 1;
1791                 revs->limited = 1;
1792                 revs->prune = 1;
1793                 load_ref_decorations(DECORATE_SHORT_REFS);
1794         } else if (!strcmp(arg, "--date-order")) {
1795                 revs->sort_order = REV_SORT_BY_COMMIT_DATE;
1796                 revs->topo_order = 1;
1797         } else if (!strcmp(arg, "--author-date-order")) {
1798                 revs->sort_order = REV_SORT_BY_AUTHOR_DATE;
1799                 revs->topo_order = 1;
1800         } else if (starts_with(arg, "--early-output")) {
1801                 int count = 100;
1802                 switch (arg[14]) {
1803                 case '=':
1804                         count = atoi(arg+15);
1805                         /* Fallthrough */
1806                 case 0:
1807                         revs->topo_order = 1;
1808                        revs->early_output = count;
1809                 }
1810         } else if (!strcmp(arg, "--parents")) {
1811                 revs->rewrite_parents = 1;
1812                 revs->print_parents = 1;
1813         } else if (!strcmp(arg, "--dense")) {
1814                 revs->dense = 1;
1815         } else if (!strcmp(arg, "--sparse")) {
1816                 revs->dense = 0;
1817         } else if (!strcmp(arg, "--show-all")) {
1818                 revs->show_all = 1;
1819         } else if (!strcmp(arg, "--remove-empty")) {
1820                 revs->remove_empty_trees = 1;
1821         } else if (!strcmp(arg, "--merges")) {
1822                 revs->min_parents = 2;
1823         } else if (!strcmp(arg, "--no-merges")) {
1824                 revs->max_parents = 1;
1825         } else if (starts_with(arg, "--min-parents=")) {
1826                 revs->min_parents = atoi(arg+14);
1827         } else if (starts_with(arg, "--no-min-parents")) {
1828                 revs->min_parents = 0;
1829         } else if (starts_with(arg, "--max-parents=")) {
1830                 revs->max_parents = atoi(arg+14);
1831         } else if (starts_with(arg, "--no-max-parents")) {
1832                 revs->max_parents = -1;
1833         } else if (!strcmp(arg, "--boundary")) {
1834                 revs->boundary = 1;
1835         } else if (!strcmp(arg, "--left-right")) {
1836                 revs->left_right = 1;
1837         } else if (!strcmp(arg, "--left-only")) {
1838                 if (revs->right_only)
1839                         die("--left-only is incompatible with --right-only"
1840                             " or --cherry");
1841                 revs->left_only = 1;
1842         } else if (!strcmp(arg, "--right-only")) {
1843                 if (revs->left_only)
1844                         die("--right-only is incompatible with --left-only");
1845                 revs->right_only = 1;
1846         } else if (!strcmp(arg, "--cherry")) {
1847                 if (revs->left_only)
1848                         die("--cherry is incompatible with --left-only");
1849                 revs->cherry_mark = 1;
1850                 revs->right_only = 1;
1851                 revs->max_parents = 1;
1852                 revs->limited = 1;
1853         } else if (!strcmp(arg, "--count")) {
1854                 revs->count = 1;
1855         } else if (!strcmp(arg, "--cherry-mark")) {
1856                 if (revs->cherry_pick)
1857                         die("--cherry-mark is incompatible with --cherry-pick");
1858                 revs->cherry_mark = 1;
1859                 revs->limited = 1; /* needs limit_list() */
1860         } else if (!strcmp(arg, "--cherry-pick")) {
1861                 if (revs->cherry_mark)
1862                         die("--cherry-pick is incompatible with --cherry-mark");
1863                 revs->cherry_pick = 1;
1864                 revs->limited = 1;
1865         } else if (!strcmp(arg, "--objects")) {
1866                 revs->tag_objects = 1;
1867                 revs->tree_objects = 1;
1868                 revs->blob_objects = 1;
1869         } else if (!strcmp(arg, "--objects-edge")) {
1870                 revs->tag_objects = 1;
1871                 revs->tree_objects = 1;
1872                 revs->blob_objects = 1;
1873                 revs->edge_hint = 1;
1874         } else if (!strcmp(arg, "--objects-edge-aggressive")) {
1875                 revs->tag_objects = 1;
1876                 revs->tree_objects = 1;
1877                 revs->blob_objects = 1;
1878                 revs->edge_hint = 1;
1879                 revs->edge_hint_aggressive = 1;
1880         } else if (!strcmp(arg, "--verify-objects")) {
1881                 revs->tag_objects = 1;
1882                 revs->tree_objects = 1;
1883                 revs->blob_objects = 1;
1884                 revs->verify_objects = 1;
1885         } else if (!strcmp(arg, "--unpacked")) {
1886                 revs->unpacked = 1;
1887         } else if (starts_with(arg, "--unpacked=")) {
1888                 die("--unpacked=<packfile> no longer supported.");
1889         } else if (!strcmp(arg, "-r")) {
1890                 revs->diff = 1;
1891                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1892         } else if (!strcmp(arg, "-t")) {
1893                 revs->diff = 1;
1894                 DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
1895                 DIFF_OPT_SET(&revs->diffopt, TREE_IN_RECURSIVE);
1896         } else if (!strcmp(arg, "-m")) {
1897                 revs->ignore_merges = 0;
1898         } else if (!strcmp(arg, "-c")) {
1899                 revs->diff = 1;
1900                 revs->dense_combined_merges = 0;
1901                 revs->combine_merges = 1;
1902         } else if (!strcmp(arg, "--cc")) {
1903                 revs->diff = 1;
1904                 revs->dense_combined_merges = 1;
1905                 revs->combine_merges = 1;
1906         } else if (!strcmp(arg, "-v")) {
1907                 revs->verbose_header = 1;
1908         } else if (!strcmp(arg, "--pretty")) {
1909                 revs->verbose_header = 1;
1910                 revs->pretty_given = 1;
1911                 get_commit_format(NULL, revs);
1912         } else if (starts_with(arg, "--pretty=") || starts_with(arg, "--format=")) {
1913                 /*
1914                  * Detached form ("--pretty X" as opposed to "--pretty=X")
1915                  * not allowed, since the argument is optional.
1916                  */
1917                 revs->verbose_header = 1;
1918                 revs->pretty_given = 1;
1919                 get_commit_format(arg+9, revs);
1920         } else if (!strcmp(arg, "--show-notes") || !strcmp(arg, "--notes")) {
1921                 revs->show_notes = 1;
1922                 revs->show_notes_given = 1;
1923                 revs->notes_opt.use_default_notes = 1;
1924         } else if (!strcmp(arg, "--show-signature")) {
1925                 revs->show_signature = 1;
1926         } else if (!strcmp(arg, "--show-linear-break") ||
1927                    starts_with(arg, "--show-linear-break=")) {
1928                 if (starts_with(arg, "--show-linear-break="))
1929                         revs->break_bar = xstrdup(arg + 20);
1930                 else
1931                         revs->break_bar = "                    ..........";
1932                 revs->track_linear = 1;
1933                 revs->track_first_time = 1;
1934         } else if (starts_with(arg, "--show-notes=") ||
1935                    starts_with(arg, "--notes=")) {
1936                 struct strbuf buf = STRBUF_INIT;
1937                 revs->show_notes = 1;
1938                 revs->show_notes_given = 1;
1939                 if (starts_with(arg, "--show-notes")) {
1940                         if (revs->notes_opt.use_default_notes < 0)
1941                                 revs->notes_opt.use_default_notes = 1;
1942                         strbuf_addstr(&buf, arg+13);
1943                 }
1944                 else
1945                         strbuf_addstr(&buf, arg+8);
1946                 expand_notes_ref(&buf);
1947                 string_list_append(&revs->notes_opt.extra_notes_refs,
1948                                    strbuf_detach(&buf, NULL));
1949         } else if (!strcmp(arg, "--no-notes")) {
1950                 revs->show_notes = 0;
1951                 revs->show_notes_given = 1;
1952                 revs->notes_opt.use_default_notes = -1;
1953                 /* we have been strdup'ing ourselves, so trick
1954                  * string_list into free()ing strings */
1955                 revs->notes_opt.extra_notes_refs.strdup_strings = 1;
1956                 string_list_clear(&revs->notes_opt.extra_notes_refs, 0);
1957                 revs->notes_opt.extra_notes_refs.strdup_strings = 0;
1958         } else if (!strcmp(arg, "--standard-notes")) {
1959                 revs->show_notes_given = 1;
1960                 revs->notes_opt.use_default_notes = 1;
1961         } else if (!strcmp(arg, "--no-standard-notes")) {
1962                 revs->notes_opt.use_default_notes = 0;
1963         } else if (!strcmp(arg, "--oneline")) {
1964                 revs->verbose_header = 1;
1965                 get_commit_format("oneline", revs);
1966                 revs->pretty_given = 1;
1967                 revs->abbrev_commit = 1;
1968         } else if (!strcmp(arg, "--graph")) {
1969                 revs->topo_order = 1;
1970                 revs->rewrite_parents = 1;
1971                 revs->graph = graph_init(revs);
1972         } else if (!strcmp(arg, "--root")) {
1973                 revs->show_root_diff = 1;
1974         } else if (!strcmp(arg, "--no-commit-id")) {
1975                 revs->no_commit_id = 1;
1976         } else if (!strcmp(arg, "--always")) {
1977                 revs->always_show_header = 1;
1978         } else if (!strcmp(arg, "--no-abbrev")) {
1979                 revs->abbrev = 0;
1980         } else if (!strcmp(arg, "--abbrev")) {
1981                 revs->abbrev = DEFAULT_ABBREV;
1982         } else if (starts_with(arg, "--abbrev=")) {
1983                 revs->abbrev = strtoul(arg + 9, NULL, 10);
1984                 if (revs->abbrev < MINIMUM_ABBREV)
1985                         revs->abbrev = MINIMUM_ABBREV;
1986                 else if (revs->abbrev > 40)
1987                         revs->abbrev = 40;
1988         } else if (!strcmp(arg, "--abbrev-commit")) {
1989                 revs->abbrev_commit = 1;
1990                 revs->abbrev_commit_given = 1;
1991         } else if (!strcmp(arg, "--no-abbrev-commit")) {
1992                 revs->abbrev_commit = 0;
1993         } else if (!strcmp(arg, "--full-diff")) {
1994                 revs->diff = 1;
1995                 revs->full_diff = 1;
1996         } else if (!strcmp(arg, "--full-history")) {
1997                 revs->simplify_history = 0;
1998         } else if (!strcmp(arg, "--relative-date")) {
1999                 revs->date_mode = DATE_RELATIVE;
2000                 revs->date_mode_explicit = 1;
2001         } else if ((argcount = parse_long_opt("date", argv, &optarg))) {
2002                 revs->date_mode = parse_date_format(optarg);
2003                 revs->date_mode_explicit = 1;
2004                 return argcount;
2005         } else if (!strcmp(arg, "--log-size")) {
2006                 revs->show_log_size = 1;
2007         }
2008         /*
2009          * Grepping the commit log
2010          */
2011         else if ((argcount = parse_long_opt("author", argv, &optarg))) {
2012                 add_header_grep(revs, GREP_HEADER_AUTHOR, optarg);
2013                 return argcount;
2014         } else if ((argcount = parse_long_opt("committer", argv, &optarg))) {
2015                 add_header_grep(revs, GREP_HEADER_COMMITTER, optarg);
2016                 return argcount;
2017         } else if ((argcount = parse_long_opt("grep-reflog", argv, &optarg))) {
2018                 add_header_grep(revs, GREP_HEADER_REFLOG, optarg);
2019                 return argcount;
2020         } else if ((argcount = parse_long_opt("grep", argv, &optarg))) {
2021                 add_message_grep(revs, optarg);
2022                 return argcount;
2023         } else if (!strcmp(arg, "--grep-debug")) {
2024                 revs->grep_filter.debug = 1;
2025         } else if (!strcmp(arg, "--basic-regexp")) {
2026                 grep_set_pattern_type_option(GREP_PATTERN_TYPE_BRE, &revs->grep_filter);
2027         } else if (!strcmp(arg, "--extended-regexp") || !strcmp(arg, "-E")) {
2028                 grep_set_pattern_type_option(GREP_PATTERN_TYPE_ERE, &revs->grep_filter);
2029         } else if (!strcmp(arg, "--regexp-ignore-case") || !strcmp(arg, "-i")) {
2030                 revs->grep_filter.regflags |= REG_ICASE;
2031                 DIFF_OPT_SET(&revs->diffopt, PICKAXE_IGNORE_CASE);
2032         } else if (!strcmp(arg, "--fixed-strings") || !strcmp(arg, "-F")) {
2033                 grep_set_pattern_type_option(GREP_PATTERN_TYPE_FIXED, &revs->grep_filter);
2034         } else if (!strcmp(arg, "--perl-regexp")) {
2035                 grep_set_pattern_type_option(GREP_PATTERN_TYPE_PCRE, &revs->grep_filter);
2036         } else if (!strcmp(arg, "--all-match")) {
2037                 revs->grep_filter.all_match = 1;
2038         } else if (!strcmp(arg, "--invert-grep")) {
2039                 revs->invert_grep = 1;
2040         } else if ((argcount = parse_long_opt("encoding", argv, &optarg))) {
2041                 if (strcmp(optarg, "none"))
2042                         git_log_output_encoding = xstrdup(optarg);
2043                 else
2044                         git_log_output_encoding = "";
2045                 return argcount;
2046         } else if (!strcmp(arg, "--reverse")) {
2047                 revs->reverse ^= 1;
2048         } else if (!strcmp(arg, "--children")) {
2049                 revs->children.name = "children";
2050                 revs->limited = 1;
2051         } else if (!strcmp(arg, "--ignore-missing")) {
2052                 revs->ignore_missing = 1;
2053         } else {
2054                 int opts = diff_opt_parse(&revs->diffopt, argv, argc);
2055                 if (!opts)
2056                         unkv[(*unkc)++] = arg;
2057                 return opts;
2058         }
2059         if (revs->graph && revs->track_linear)
2060                 die("--show-linear-break and --graph are incompatible");
2061
2062         return 1;
2063 }
2064
2065 void parse_revision_opt(struct rev_info *revs, struct parse_opt_ctx_t *ctx,
2066                         const struct option *options,
2067                         const char * const usagestr[])
2068 {
2069         int n = handle_revision_opt(revs, ctx->argc, ctx->argv,
2070                                     &ctx->cpidx, ctx->out);
2071         if (n <= 0) {
2072                 error("unknown option `%s'", ctx->argv[0]);
2073                 usage_with_options(usagestr, options);
2074         }
2075         ctx->argv += n;
2076         ctx->argc -= n;
2077 }
2078
2079 static int for_each_bad_bisect_ref(const char *submodule, each_ref_fn fn, void *cb_data)
2080 {
2081         return for_each_ref_in_submodule(submodule, "refs/bisect/bad", fn, cb_data);
2082 }
2083
2084 static int for_each_good_bisect_ref(const char *submodule, each_ref_fn fn, void *cb_data)
2085 {
2086         return for_each_ref_in_submodule(submodule, "refs/bisect/good", fn, cb_data);
2087 }
2088
2089 static int handle_revision_pseudo_opt(const char *submodule,
2090                                 struct rev_info *revs,
2091                                 int argc, const char **argv, int *flags)
2092 {
2093         const char *arg = argv[0];
2094         const char *optarg;
2095         int argcount;
2096
2097         /*
2098          * NOTE!
2099          *
2100          * Commands like "git shortlog" will not accept the options below
2101          * unless parse_revision_opt queues them (as opposed to erroring
2102          * out).
2103          *
2104          * When implementing your new pseudo-option, remember to
2105          * register it in the list at the top of handle_revision_opt.
2106          */
2107         if (!strcmp(arg, "--all")) {
2108                 handle_refs(submodule, revs, *flags, for_each_ref_submodule);
2109                 handle_refs(submodule, revs, *flags, head_ref_submodule);
2110                 clear_ref_exclusion(&revs->ref_excludes);
2111         } else if (!strcmp(arg, "--branches")) {
2112                 handle_refs(submodule, revs, *flags, for_each_branch_ref_submodule);
2113                 clear_ref_exclusion(&revs->ref_excludes);
2114         } else if (!strcmp(arg, "--bisect")) {
2115                 handle_refs(submodule, revs, *flags, for_each_bad_bisect_ref);
2116                 handle_refs(submodule, revs, *flags ^ (UNINTERESTING | BOTTOM), for_each_good_bisect_ref);
2117                 revs->bisect = 1;
2118         } else if (!strcmp(arg, "--tags")) {
2119                 handle_refs(submodule, revs, *flags, for_each_tag_ref_submodule);
2120                 clear_ref_exclusion(&revs->ref_excludes);
2121         } else if (!strcmp(arg, "--remotes")) {
2122                 handle_refs(submodule, revs, *flags, for_each_remote_ref_submodule);
2123                 clear_ref_exclusion(&revs->ref_excludes);
2124         } else if ((argcount = parse_long_opt("glob", argv, &optarg))) {
2125                 struct all_refs_cb cb;
2126                 init_all_refs_cb(&cb, revs, *flags);
2127                 for_each_glob_ref(handle_one_ref, optarg, &cb);
2128                 clear_ref_exclusion(&revs->ref_excludes);
2129                 return argcount;
2130         } else if ((argcount = parse_long_opt("exclude", argv, &optarg))) {
2131                 add_ref_exclusion(&revs->ref_excludes, optarg);
2132                 return argcount;
2133         } else if (starts_with(arg, "--branches=")) {
2134                 struct all_refs_cb cb;
2135                 init_all_refs_cb(&cb, revs, *flags);
2136                 for_each_glob_ref_in(handle_one_ref, arg + 11, "refs/heads/", &cb);
2137                 clear_ref_exclusion(&revs->ref_excludes);
2138         } else if (starts_with(arg, "--tags=")) {
2139                 struct all_refs_cb cb;
2140                 init_all_refs_cb(&cb, revs, *flags);
2141                 for_each_glob_ref_in(handle_one_ref, arg + 7, "refs/tags/", &cb);
2142                 clear_ref_exclusion(&revs->ref_excludes);
2143         } else if (starts_with(arg, "--remotes=")) {
2144                 struct all_refs_cb cb;
2145                 init_all_refs_cb(&cb, revs, *flags);
2146                 for_each_glob_ref_in(handle_one_ref, arg + 10, "refs/remotes/", &cb);
2147                 clear_ref_exclusion(&revs->ref_excludes);
2148         } else if (!strcmp(arg, "--reflog")) {
2149                 add_reflogs_to_pending(revs, *flags);
2150         } else if (!strcmp(arg, "--indexed-objects")) {
2151                 add_index_objects_to_pending(revs, *flags);
2152         } else if (!strcmp(arg, "--not")) {
2153                 *flags ^= UNINTERESTING | BOTTOM;
2154         } else if (!strcmp(arg, "--no-walk")) {
2155                 revs->no_walk = REVISION_WALK_NO_WALK_SORTED;
2156         } else if (starts_with(arg, "--no-walk=")) {
2157                 /*
2158                  * Detached form ("--no-walk X" as opposed to "--no-walk=X")
2159                  * not allowed, since the argument is optional.
2160                  */
2161                 if (!strcmp(arg + 10, "sorted"))
2162                         revs->no_walk = REVISION_WALK_NO_WALK_SORTED;
2163                 else if (!strcmp(arg + 10, "unsorted"))
2164                         revs->no_walk = REVISION_WALK_NO_WALK_UNSORTED;
2165                 else
2166                         return error("invalid argument to --no-walk");
2167         } else if (!strcmp(arg, "--do-walk")) {
2168                 revs->no_walk = 0;
2169         } else {
2170                 return 0;
2171         }
2172
2173         return 1;
2174 }
2175
2176 static void NORETURN diagnose_missing_default(const char *def)
2177 {
2178         unsigned char sha1[20];
2179         int flags;
2180         const char *refname;
2181
2182         refname = resolve_ref_unsafe(def, 0, sha1, &flags);
2183         if (!refname || !(flags & REF_ISSYMREF) || (flags & REF_ISBROKEN))
2184                 die(_("your current branch appears to be broken"));
2185
2186         skip_prefix(refname, "refs/heads/", &refname);
2187         die(_("your current branch '%s' does not have any commits yet"),
2188             refname);
2189 }
2190
2191 /*
2192  * Parse revision information, filling in the "rev_info" structure,
2193  * and removing the used arguments from the argument list.
2194  *
2195  * Returns the number of arguments left that weren't recognized
2196  * (which are also moved to the head of the argument list)
2197  */
2198 int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct setup_revision_opt *opt)
2199 {
2200         int i, flags, left, seen_dashdash, read_from_stdin, got_rev_arg = 0, revarg_opt;
2201         struct cmdline_pathspec prune_data;
2202         const char *submodule = NULL;
2203
2204         memset(&prune_data, 0, sizeof(prune_data));
2205         if (opt)
2206                 submodule = opt->submodule;
2207
2208         /* First, search for "--" */
2209         if (opt && opt->assume_dashdash) {
2210                 seen_dashdash = 1;
2211         } else {
2212                 seen_dashdash = 0;
2213                 for (i = 1; i < argc; i++) {
2214                         const char *arg = argv[i];
2215                         if (strcmp(arg, "--"))
2216                                 continue;
2217                         argv[i] = NULL;
2218                         argc = i;
2219                         if (argv[i + 1])
2220                                 append_prune_data(&prune_data, argv + i + 1);
2221                         seen_dashdash = 1;
2222                         break;
2223                 }
2224         }
2225
2226         /* Second, deal with arguments and options */
2227         flags = 0;
2228         revarg_opt = opt ? opt->revarg_opt : 0;
2229         if (seen_dashdash)
2230                 revarg_opt |= REVARG_CANNOT_BE_FILENAME;
2231         read_from_stdin = 0;
2232         for (left = i = 1; i < argc; i++) {
2233                 const char *arg = argv[i];
2234                 if (*arg == '-') {
2235                         int opts;
2236
2237                         opts = handle_revision_pseudo_opt(submodule,
2238                                                 revs, argc - i, argv + i,
2239                                                 &flags);
2240                         if (opts > 0) {
2241                                 i += opts - 1;
2242                                 continue;
2243                         }
2244
2245                         if (!strcmp(arg, "--stdin")) {
2246                                 if (revs->disable_stdin) {
2247                                         argv[left++] = arg;
2248                                         continue;
2249                                 }
2250                                 if (read_from_stdin++)
2251                                         die("--stdin given twice?");
2252                                 read_revisions_from_stdin(revs, &prune_data);
2253                                 continue;
2254                         }
2255
2256                         opts = handle_revision_opt(revs, argc - i, argv + i, &left, argv);
2257                         if (opts > 0) {
2258                                 i += opts - 1;
2259                                 continue;
2260                         }
2261                         if (opts < 0)
2262                                 exit(128);
2263                         continue;
2264                 }
2265
2266
2267                 if (handle_revision_arg(arg, revs, flags, revarg_opt)) {
2268                         int j;
2269                         if (seen_dashdash || *arg == '^')
2270                                 die("bad revision '%s'", arg);
2271
2272                         /* If we didn't have a "--":
2273                          * (1) all filenames must exist;
2274                          * (2) all rev-args must not be interpretable
2275                          *     as a valid filename.
2276                          * but the latter we have checked in the main loop.
2277                          */
2278                         for (j = i; j < argc; j++)
2279                                 verify_filename(revs->prefix, argv[j], j == i);
2280
2281                         append_prune_data(&prune_data, argv + i);
2282                         break;
2283                 }
2284                 else
2285                         got_rev_arg = 1;
2286         }
2287
2288         if (prune_data.nr) {
2289                 /*
2290                  * If we need to introduce the magic "a lone ':' means no
2291                  * pathspec whatsoever", here is the place to do so.
2292                  *
2293                  * if (prune_data.nr == 1 && !strcmp(prune_data[0], ":")) {
2294                  *      prune_data.nr = 0;
2295                  *      prune_data.alloc = 0;
2296                  *      free(prune_data.path);
2297                  *      prune_data.path = NULL;
2298                  * } else {
2299                  *      terminate prune_data.alloc with NULL and
2300                  *      call init_pathspec() to set revs->prune_data here.
2301                  * }
2302                  */
2303                 ALLOC_GROW(prune_data.path, prune_data.nr + 1, prune_data.alloc);
2304                 prune_data.path[prune_data.nr++] = NULL;
2305                 parse_pathspec(&revs->prune_data, 0, 0,
2306                                revs->prefix, prune_data.path);
2307         }
2308
2309         if (revs->def == NULL)
2310                 revs->def = opt ? opt->def : NULL;
2311         if (opt && opt->tweak)
2312                 opt->tweak(revs, opt);
2313         if (revs->show_merge)
2314                 prepare_show_merge(revs);
2315         if (revs->def && !revs->pending.nr && !got_rev_arg) {
2316                 unsigned char sha1[20];
2317                 struct object *object;
2318                 struct object_context oc;
2319                 if (get_sha1_with_context(revs->def, 0, sha1, &oc))
2320                         diagnose_missing_default(revs->def);
2321                 object = get_reference(revs, revs->def, sha1, 0);
2322                 add_pending_object_with_mode(revs, object, revs->def, oc.mode);
2323         }
2324
2325         /* Did the user ask for any diff output? Run the diff! */
2326         if (revs->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT)
2327                 revs->diff = 1;
2328
2329         /* Pickaxe, diff-filter and rename following need diffs */
2330         if (revs->diffopt.pickaxe ||
2331             revs->diffopt.filter ||
2332             DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
2333                 revs->diff = 1;
2334
2335         if (revs->topo_order)
2336                 revs->limited = 1;
2337
2338         if (revs->prune_data.nr) {
2339                 copy_pathspec(&revs->pruning.pathspec, &revs->prune_data);
2340                 /* Can't prune commits with rename following: the paths change.. */
2341                 if (!DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
2342                         revs->prune = 1;
2343                 if (!revs->full_diff)
2344                         copy_pathspec(&revs->diffopt.pathspec,
2345                                       &revs->prune_data);
2346         }
2347         if (revs->combine_merges)
2348                 revs->ignore_merges = 0;
2349         revs->diffopt.abbrev = revs->abbrev;
2350
2351         if (revs->line_level_traverse) {
2352                 revs->limited = 1;
2353                 revs->topo_order = 1;
2354         }
2355
2356         diff_setup_done(&revs->diffopt);
2357
2358         grep_commit_pattern_type(GREP_PATTERN_TYPE_UNSPECIFIED,
2359                                  &revs->grep_filter);
2360         compile_grep_patterns(&revs->grep_filter);
2361
2362         if (revs->reverse && revs->reflog_info)
2363                 die("cannot combine --reverse with --walk-reflogs");
2364         if (revs->rewrite_parents && revs->children.name)
2365                 die("cannot combine --parents and --children");
2366
2367         /*
2368          * Limitations on the graph functionality
2369          */
2370         if (revs->reverse && revs->graph)
2371                 die("cannot combine --reverse with --graph");
2372
2373         if (revs->reflog_info && revs->graph)
2374                 die("cannot combine --walk-reflogs with --graph");
2375         if (revs->no_walk && revs->graph)
2376                 die("cannot combine --no-walk with --graph");
2377         if (!revs->reflog_info && revs->grep_filter.use_reflog_filter)
2378                 die("cannot use --grep-reflog without --walk-reflogs");
2379
2380         if (revs->first_parent_only && revs->bisect)
2381                 die(_("--first-parent is incompatible with --bisect"));
2382
2383         return left;
2384 }
2385
2386 static void add_child(struct rev_info *revs, struct commit *parent, struct commit *child)
2387 {
2388         struct commit_list *l = xcalloc(1, sizeof(*l));
2389
2390         l->item = child;
2391         l->next = add_decoration(&revs->children, &parent->object, l);
2392 }
2393
2394 static int remove_duplicate_parents(struct rev_info *revs, struct commit *commit)
2395 {
2396         struct treesame_state *ts = lookup_decoration(&revs->treesame, &commit->object);
2397         struct commit_list **pp, *p;
2398         int surviving_parents;
2399
2400         /* Examine existing parents while marking ones we have seen... */
2401         pp = &commit->parents;
2402         surviving_parents = 0;
2403         while ((p = *pp) != NULL) {
2404                 struct commit *parent = p->item;
2405                 if (parent->object.flags & TMP_MARK) {
2406                         *pp = p->next;
2407                         if (ts)
2408                                 compact_treesame(revs, commit, surviving_parents);
2409                         continue;
2410                 }
2411                 parent->object.flags |= TMP_MARK;
2412                 surviving_parents++;
2413                 pp = &p->next;
2414         }
2415         /* clear the temporary mark */
2416         for (p = commit->parents; p; p = p->next) {
2417                 p->item->object.flags &= ~TMP_MARK;
2418         }
2419         /* no update_treesame() - removing duplicates can't affect TREESAME */
2420         return surviving_parents;
2421 }
2422
2423 struct merge_simplify_state {
2424         struct commit *simplified;
2425 };
2426
2427 static struct merge_simplify_state *locate_simplify_state(struct rev_info *revs, struct commit *commit)
2428 {
2429         struct merge_simplify_state *st;
2430
2431         st = lookup_decoration(&revs->merge_simplification, &commit->object);
2432         if (!st) {
2433                 st = xcalloc(1, sizeof(*st));
2434                 add_decoration(&revs->merge_simplification, &commit->object, st);
2435         }
2436         return st;
2437 }
2438
2439 static int mark_redundant_parents(struct rev_info *revs, struct commit *commit)
2440 {
2441         struct commit_list *h = reduce_heads(commit->parents);
2442         int i = 0, marked = 0;
2443         struct commit_list *po, *pn;
2444
2445         /* Want these for sanity-checking only */
2446         int orig_cnt = commit_list_count(commit->parents);
2447         int cnt = commit_list_count(h);
2448
2449         /*
2450          * Not ready to remove items yet, just mark them for now, based
2451          * on the output of reduce_heads(). reduce_heads outputs the reduced
2452          * set in its original order, so this isn't too hard.
2453          */
2454         po = commit->parents;
2455         pn = h;
2456         while (po) {
2457                 if (pn && po->item == pn->item) {
2458                         pn = pn->next;
2459                         i++;
2460                 } else {
2461                         po->item->object.flags |= TMP_MARK;
2462                         marked++;
2463                 }
2464                 po=po->next;
2465         }
2466
2467         if (i != cnt || cnt+marked != orig_cnt)
2468                 die("mark_redundant_parents %d %d %d %d", orig_cnt, cnt, i, marked);
2469
2470         free_commit_list(h);
2471
2472         return marked;
2473 }
2474
2475 static int mark_treesame_root_parents(struct rev_info *revs, struct commit *commit)
2476 {
2477         struct commit_list *p;
2478         int marked = 0;
2479
2480         for (p = commit->parents; p; p = p->next) {
2481                 struct commit *parent = p->item;
2482                 if (!parent->parents && (parent->object.flags & TREESAME)) {
2483                         parent->object.flags |= TMP_MARK;
2484                         marked++;
2485                 }
2486         }
2487
2488         return marked;
2489 }
2490
2491 /*
2492  * Awkward naming - this means one parent we are TREESAME to.
2493  * cf mark_treesame_root_parents: root parents that are TREESAME (to an
2494  * empty tree). Better name suggestions?
2495  */
2496 static int leave_one_treesame_to_parent(struct rev_info *revs, struct commit *commit)
2497 {
2498         struct treesame_state *ts = lookup_decoration(&revs->treesame, &commit->object);
2499         struct commit *unmarked = NULL, *marked = NULL;
2500         struct commit_list *p;
2501         unsigned n;
2502
2503         for (p = commit->parents, n = 0; p; p = p->next, n++) {
2504                 if (ts->treesame[n]) {
2505                         if (p->item->object.flags & TMP_MARK) {
2506                                 if (!marked)
2507                                         marked = p->item;
2508                         } else {
2509                                 if (!unmarked) {
2510                                         unmarked = p->item;
2511                                         break;
2512                                 }
2513                         }
2514                 }
2515         }
2516
2517         /*
2518          * If we are TREESAME to a marked-for-deletion parent, but not to any
2519          * unmarked parents, unmark the first TREESAME parent. This is the
2520          * parent that the default simplify_history==1 scan would have followed,
2521          * and it doesn't make sense to omit that path when asking for a
2522          * simplified full history. Retaining it improves the chances of
2523          * understanding odd missed merges that took an old version of a file.
2524          *
2525          * Example:
2526          *
2527          *   I--------*X       A modified the file, but mainline merge X used
2528          *    \       /        "-s ours", so took the version from I. X is
2529          *     `-*A--'         TREESAME to I and !TREESAME to A.
2530          *
2531          * Default log from X would produce "I". Without this check,
2532          * --full-history --simplify-merges would produce "I-A-X", showing
2533          * the merge commit X and that it changed A, but not making clear that
2534          * it had just taken the I version. With this check, the topology above
2535          * is retained.
2536          *
2537          * Note that it is possible that the simplification chooses a different
2538          * TREESAME parent from the default, in which case this test doesn't
2539          * activate, and we _do_ drop the default parent. Example:
2540          *
2541          *   I------X         A modified the file, but it was reverted in B,
2542          *    \    /          meaning mainline merge X is TREESAME to both
2543          *    *A-*B           parents.
2544          *
2545          * Default log would produce "I" by following the first parent;
2546          * --full-history --simplify-merges will produce "I-A-B". But this is a
2547          * reasonable result - it presents a logical full history leading from
2548          * I to X, and X is not an important merge.
2549          */
2550         if (!unmarked && marked) {
2551                 marked->object.flags &= ~TMP_MARK;
2552                 return 1;
2553         }
2554
2555         return 0;
2556 }
2557
2558 static int remove_marked_parents(struct rev_info *revs, struct commit *commit)
2559 {
2560         struct commit_list **pp, *p;
2561         int nth_parent, removed = 0;
2562
2563         pp = &commit->parents;
2564         nth_parent = 0;
2565         while ((p = *pp) != NULL) {
2566                 struct commit *parent = p->item;
2567                 if (parent->object.flags & TMP_MARK) {
2568                         parent->object.flags &= ~TMP_MARK;
2569                         *pp = p->next;
2570                         free(p);
2571                         removed++;
2572                         compact_treesame(revs, commit, nth_parent);
2573                         continue;
2574                 }
2575                 pp = &p->next;
2576                 nth_parent++;
2577         }
2578
2579         /* Removing parents can only increase TREESAMEness */
2580         if (removed && !(commit->object.flags & TREESAME))
2581                 update_treesame(revs, commit);
2582
2583         return nth_parent;
2584 }
2585
2586 static struct commit_list **simplify_one(struct rev_info *revs, struct commit *commit, struct commit_list **tail)
2587 {
2588         struct commit_list *p;
2589         struct commit *parent;
2590         struct merge_simplify_state *st, *pst;
2591         int cnt;
2592
2593         st = locate_simplify_state(revs, commit);
2594
2595         /*
2596          * Have we handled this one?
2597          */
2598         if (st->simplified)
2599                 return tail;
2600
2601         /*
2602          * An UNINTERESTING commit simplifies to itself, so does a
2603          * root commit.  We do not rewrite parents of such commit
2604          * anyway.
2605          */
2606         if ((commit->object.flags & UNINTERESTING) || !commit->parents) {
2607                 st->simplified = commit;
2608                 return tail;
2609         }
2610
2611         /*
2612          * Do we know what commit all of our parents that matter
2613          * should be rewritten to?  Otherwise we are not ready to
2614          * rewrite this one yet.
2615          */
2616         for (cnt = 0, p = commit->parents; p; p = p->next) {
2617                 pst = locate_simplify_state(revs, p->item);
2618                 if (!pst->simplified) {
2619                         tail = &commit_list_insert(p->item, tail)->next;
2620                         cnt++;
2621                 }
2622                 if (revs->first_parent_only)
2623                         break;
2624         }
2625         if (cnt) {
2626                 tail = &commit_list_insert(commit, tail)->next;
2627                 return tail;
2628         }
2629
2630         /*
2631          * Rewrite our list of parents. Note that this cannot
2632          * affect our TREESAME flags in any way - a commit is
2633          * always TREESAME to its simplification.
2634          */
2635         for (p = commit->parents; p; p = p->next) {
2636                 pst = locate_simplify_state(revs, p->item);
2637                 p->item = pst->simplified;
2638                 if (revs->first_parent_only)
2639                         break;
2640         }
2641
2642         if (revs->first_parent_only)
2643                 cnt = 1;
2644         else
2645                 cnt = remove_duplicate_parents(revs, commit);
2646
2647         /*
2648          * It is possible that we are a merge and one side branch
2649          * does not have any commit that touches the given paths;
2650          * in such a case, the immediate parent from that branch
2651          * will be rewritten to be the merge base.
2652          *
2653          *      o----X          X: the commit we are looking at;
2654          *     /    /           o: a commit that touches the paths;
2655          * ---o----'
2656          *
2657          * Further, a merge of an independent branch that doesn't
2658          * touch the path will reduce to a treesame root parent:
2659          *
2660          *  ----o----X          X: the commit we are looking at;
2661          *          /           o: a commit that touches the paths;
2662          *         r            r: a root commit not touching the paths
2663          *
2664          * Detect and simplify both cases.
2665          */
2666         if (1 < cnt) {
2667                 int marked = mark_redundant_parents(revs, commit);
2668                 marked += mark_treesame_root_parents(revs, commit);
2669                 if (marked)
2670                         marked -= leave_one_treesame_to_parent(revs, commit);
2671                 if (marked)
2672                         cnt = remove_marked_parents(revs, commit);
2673         }
2674
2675         /*
2676          * A commit simplifies to itself if it is a root, if it is
2677          * UNINTERESTING, if it touches the given paths, or if it is a
2678          * merge and its parents don't simplify to one relevant commit
2679          * (the first two cases are already handled at the beginning of
2680          * this function).
2681          *
2682          * Otherwise, it simplifies to what its sole relevant parent
2683          * simplifies to.
2684          */
2685         if (!cnt ||
2686             (commit->object.flags & UNINTERESTING) ||
2687             !(commit->object.flags & TREESAME) ||
2688             (parent = one_relevant_parent(revs, commit->parents)) == NULL)
2689                 st->simplified = commit;
2690         else {
2691                 pst = locate_simplify_state(revs, parent);
2692                 st->simplified = pst->simplified;
2693         }
2694         return tail;
2695 }
2696
2697 static void simplify_merges(struct rev_info *revs)
2698 {
2699         struct commit_list *list, *next;
2700         struct commit_list *yet_to_do, **tail;
2701         struct commit *commit;
2702
2703         if (!revs->prune)
2704                 return;
2705
2706         /* feed the list reversed */
2707         yet_to_do = NULL;
2708         for (list = revs->commits; list; list = next) {
2709                 commit = list->item;
2710                 next = list->next;
2711                 /*
2712                  * Do not free(list) here yet; the original list
2713                  * is used later in this function.
2714                  */
2715                 commit_list_insert(commit, &yet_to_do);
2716         }
2717         while (yet_to_do) {
2718                 list = yet_to_do;
2719                 yet_to_do = NULL;
2720                 tail = &yet_to_do;
2721                 while (list) {
2722                         commit = list->item;
2723                         next = list->next;
2724                         free(list);
2725                         list = next;
2726                         tail = simplify_one(revs, commit, tail);
2727                 }
2728         }
2729
2730         /* clean up the result, removing the simplified ones */
2731         list = revs->commits;
2732         revs->commits = NULL;
2733         tail = &revs->commits;
2734         while (list) {
2735                 struct merge_simplify_state *st;
2736
2737                 commit = list->item;
2738                 next = list->next;
2739                 free(list);
2740                 list = next;
2741                 st = locate_simplify_state(revs, commit);
2742                 if (st->simplified == commit)
2743                         tail = &commit_list_insert(commit, tail)->next;
2744         }
2745 }
2746
2747 static void set_children(struct rev_info *revs)
2748 {
2749         struct commit_list *l;
2750         for (l = revs->commits; l; l = l->next) {
2751                 struct commit *commit = l->item;
2752                 struct commit_list *p;
2753
2754                 for (p = commit->parents; p; p = p->next)
2755                         add_child(revs, p->item, commit);
2756         }
2757 }
2758
2759 void reset_revision_walk(void)
2760 {
2761         clear_object_flags(SEEN | ADDED | SHOWN);
2762 }
2763
2764 int prepare_revision_walk(struct rev_info *revs)
2765 {
2766         int i;
2767         struct object_array old_pending;
2768         struct commit_list **next = &revs->commits;
2769
2770         memcpy(&old_pending, &revs->pending, sizeof(old_pending));
2771         revs->pending.nr = 0;
2772         revs->pending.alloc = 0;
2773         revs->pending.objects = NULL;
2774         for (i = 0; i < old_pending.nr; i++) {
2775                 struct object_array_entry *e = old_pending.objects + i;
2776                 struct commit *commit = handle_commit(revs, e);
2777                 if (commit) {
2778                         if (!(commit->object.flags & SEEN)) {
2779                                 commit->object.flags |= SEEN;
2780                                 next = commit_list_append(commit, next);
2781                         }
2782                 }
2783         }
2784         if (!revs->leak_pending)
2785                 object_array_clear(&old_pending);
2786
2787         /* Signal whether we need per-parent treesame decoration */
2788         if (revs->simplify_merges ||
2789             (revs->limited && limiting_can_increase_treesame(revs)))
2790                 revs->treesame.name = "treesame";
2791
2792         if (revs->no_walk != REVISION_WALK_NO_WALK_UNSORTED)
2793                 commit_list_sort_by_date(&revs->commits);
2794         if (revs->no_walk)
2795                 return 0;
2796         if (revs->limited)
2797                 if (limit_list(revs) < 0)
2798                         return -1;
2799         if (revs->topo_order)
2800                 sort_in_topological_order(&revs->commits, revs->sort_order);
2801         if (revs->line_level_traverse)
2802                 line_log_filter(revs);
2803         if (revs->simplify_merges)
2804                 simplify_merges(revs);
2805         if (revs->children.name)
2806                 set_children(revs);
2807         return 0;
2808 }
2809
2810 static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp)
2811 {
2812         struct commit_list *cache = NULL;
2813
2814         for (;;) {
2815                 struct commit *p = *pp;
2816                 if (!revs->limited)
2817                         if (add_parents_to_list(revs, p, &revs->commits, &cache) < 0)
2818                                 return rewrite_one_error;
2819                 if (p->object.flags & UNINTERESTING)
2820                         return rewrite_one_ok;
2821                 if (!(p->object.flags & TREESAME))
2822                         return rewrite_one_ok;
2823                 if (!p->parents)
2824                         return rewrite_one_noparents;
2825                 if ((p = one_relevant_parent(revs, p->parents)) == NULL)
2826                         return rewrite_one_ok;
2827                 *pp = p;
2828         }
2829 }
2830
2831 int rewrite_parents(struct rev_info *revs, struct commit *commit,
2832         rewrite_parent_fn_t rewrite_parent)
2833 {
2834         struct commit_list **pp = &commit->parents;
2835         while (*pp) {
2836                 struct commit_list *parent = *pp;
2837                 switch (rewrite_parent(revs, &parent->item)) {
2838                 case rewrite_one_ok:
2839                         break;
2840                 case rewrite_one_noparents:
2841                         *pp = parent->next;
2842                         continue;
2843                 case rewrite_one_error:
2844                         return -1;
2845                 }
2846                 pp = &parent->next;
2847         }
2848         remove_duplicate_parents(revs, commit);
2849         return 0;
2850 }
2851
2852 static int commit_rewrite_person(struct strbuf *buf, const char *what, struct string_list *mailmap)
2853 {
2854         char *person, *endp;
2855         size_t len, namelen, maillen;
2856         const char *name;
2857         const char *mail;
2858         struct ident_split ident;
2859
2860         person = strstr(buf->buf, what);
2861         if (!person)
2862                 return 0;
2863
2864         person += strlen(what);
2865         endp = strchr(person, '\n');
2866         if (!endp)
2867                 return 0;
2868
2869         len = endp - person;
2870
2871         if (split_ident_line(&ident, person, len))
2872                 return 0;
2873
2874         mail = ident.mail_begin;
2875         maillen = ident.mail_end - ident.mail_begin;
2876         name = ident.name_begin;
2877         namelen = ident.name_end - ident.name_begin;
2878
2879         if (map_user(mailmap, &mail, &maillen, &name, &namelen)) {
2880                 struct strbuf namemail = STRBUF_INIT;
2881
2882                 strbuf_addf(&namemail, "%.*s <%.*s>",
2883                             (int)namelen, name, (int)maillen, mail);
2884
2885                 strbuf_splice(buf, ident.name_begin - buf->buf,
2886                               ident.mail_end - ident.name_begin + 1,
2887                               namemail.buf, namemail.len);
2888
2889                 strbuf_release(&namemail);
2890
2891                 return 1;
2892         }
2893
2894         return 0;
2895 }
2896
2897 static int commit_match(struct commit *commit, struct rev_info *opt)
2898 {
2899         int retval;
2900         const char *encoding;
2901         const char *message;
2902         struct strbuf buf = STRBUF_INIT;
2903
2904         if (!opt->grep_filter.pattern_list && !opt->grep_filter.header_list)
2905                 return 1;
2906
2907         /* Prepend "fake" headers as needed */
2908         if (opt->grep_filter.use_reflog_filter) {
2909                 strbuf_addstr(&buf, "reflog ");
2910                 get_reflog_message(&buf, opt->reflog_info);
2911                 strbuf_addch(&buf, '\n');
2912         }
2913
2914         /*
2915          * We grep in the user's output encoding, under the assumption that it
2916          * is the encoding they are most likely to write their grep pattern
2917          * for. In addition, it means we will match the "notes" encoding below,
2918          * so we will not end up with a buffer that has two different encodings
2919          * in it.
2920          */
2921         encoding = get_log_output_encoding();
2922         message = logmsg_reencode(commit, NULL, encoding);
2923
2924         /* Copy the commit to temporary if we are using "fake" headers */
2925         if (buf.len)
2926                 strbuf_addstr(&buf, message);
2927
2928         if (opt->grep_filter.header_list && opt->mailmap) {
2929                 if (!buf.len)
2930                         strbuf_addstr(&buf, message);
2931
2932                 commit_rewrite_person(&buf, "\nauthor ", opt->mailmap);
2933                 commit_rewrite_person(&buf, "\ncommitter ", opt->mailmap);
2934         }
2935
2936         /* Append "fake" message parts as needed */
2937         if (opt->show_notes) {
2938                 if (!buf.len)
2939                         strbuf_addstr(&buf, message);
2940                 format_display_notes(commit->object.sha1, &buf, encoding, 1);
2941         }
2942
2943         /*
2944          * Find either in the original commit message, or in the temporary.
2945          * Note that we cast away the constness of "message" here. It is
2946          * const because it may come from the cached commit buffer. That's OK,
2947          * because we know that it is modifiable heap memory, and that while
2948          * grep_buffer may modify it for speed, it will restore any
2949          * changes before returning.
2950          */
2951         if (buf.len)
2952                 retval = grep_buffer(&opt->grep_filter, buf.buf, buf.len);
2953         else
2954                 retval = grep_buffer(&opt->grep_filter,
2955                                      (char *)message, strlen(message));
2956         strbuf_release(&buf);
2957         unuse_commit_buffer(commit, message);
2958         return opt->invert_grep ? !retval : retval;
2959 }
2960
2961 static inline int want_ancestry(const struct rev_info *revs)
2962 {
2963         return (revs->rewrite_parents || revs->children.name);
2964 }
2965
2966 enum commit_action get_commit_action(struct rev_info *revs, struct commit *commit)
2967 {
2968         if (commit->object.flags & SHOWN)
2969                 return commit_ignore;
2970         if (revs->unpacked && has_sha1_pack(commit->object.sha1))
2971                 return commit_ignore;
2972         if (revs->show_all)
2973                 return commit_show;
2974         if (commit->object.flags & UNINTERESTING)
2975                 return commit_ignore;
2976         if (revs->min_age != -1 && (commit->date > revs->min_age))
2977                 return commit_ignore;
2978         if (revs->min_parents || (revs->max_parents >= 0)) {
2979                 int n = commit_list_count(commit->parents);
2980                 if ((n < revs->min_parents) ||
2981                     ((revs->max_parents >= 0) && (n > revs->max_parents)))
2982                         return commit_ignore;
2983         }
2984         if (!commit_match(commit, revs))
2985                 return commit_ignore;
2986         if (revs->prune && revs->dense) {
2987                 /* Commit without changes? */
2988                 if (commit->object.flags & TREESAME) {
2989                         int n;
2990                         struct commit_list *p;
2991                         /* drop merges unless we want parenthood */
2992                         if (!want_ancestry(revs))
2993                                 return commit_ignore;
2994                         /*
2995                          * If we want ancestry, then need to keep any merges
2996                          * between relevant commits to tie together topology.
2997                          * For consistency with TREESAME and simplification
2998                          * use "relevant" here rather than just INTERESTING,
2999                          * to treat bottom commit(s) as part of the topology.
3000                          */
3001                         for (n = 0, p = commit->parents; p; p = p->next)
3002                                 if (relevant_commit(p->item))
3003                                         if (++n >= 2)
3004                                                 return commit_show;
3005                         return commit_ignore;
3006                 }
3007         }
3008         return commit_show;
3009 }
3010
3011 define_commit_slab(saved_parents, struct commit_list *);
3012
3013 #define EMPTY_PARENT_LIST ((struct commit_list *)-1)
3014
3015 /*
3016  * You may only call save_parents() once per commit (this is checked
3017  * for non-root commits).
3018  */
3019 static void save_parents(struct rev_info *revs, struct commit *commit)
3020 {
3021         struct commit_list **pp;
3022
3023         if (!revs->saved_parents_slab) {
3024                 revs->saved_parents_slab = xmalloc(sizeof(struct saved_parents));
3025                 init_saved_parents(revs->saved_parents_slab);
3026         }
3027
3028         pp = saved_parents_at(revs->saved_parents_slab, commit);
3029
3030         /*
3031          * When walking with reflogs, we may visit the same commit
3032          * several times: once for each appearance in the reflog.
3033          *
3034          * In this case, save_parents() will be called multiple times.
3035          * We want to keep only the first set of parents.  We need to
3036          * store a sentinel value for an empty (i.e., NULL) parent
3037          * list to distinguish it from a not-yet-saved list, however.
3038          */
3039         if (*pp)
3040                 return;
3041         if (commit->parents)
3042                 *pp = copy_commit_list(commit->parents);
3043         else
3044                 *pp = EMPTY_PARENT_LIST;
3045 }
3046
3047 static void free_saved_parents(struct rev_info *revs)
3048 {
3049         if (revs->saved_parents_slab)
3050                 clear_saved_parents(revs->saved_parents_slab);
3051 }
3052
3053 struct commit_list *get_saved_parents(struct rev_info *revs, const struct commit *commit)
3054 {
3055         struct commit_list *parents;
3056
3057         if (!revs->saved_parents_slab)
3058                 return commit->parents;
3059
3060         parents = *saved_parents_at(revs->saved_parents_slab, commit);
3061         if (parents == EMPTY_PARENT_LIST)
3062                 return NULL;
3063         return parents;
3064 }
3065
3066 enum commit_action simplify_commit(struct rev_info *revs, struct commit *commit)
3067 {
3068         enum commit_action action = get_commit_action(revs, commit);
3069
3070         if (action == commit_show &&
3071             !revs->show_all &&
3072             revs->prune && revs->dense && want_ancestry(revs)) {
3073                 /*
3074                  * --full-diff on simplified parents is no good: it
3075                  * will show spurious changes from the commits that
3076                  * were elided.  So we save the parents on the side
3077                  * when --full-diff is in effect.
3078                  */
3079                 if (revs->full_diff)
3080                         save_parents(revs, commit);
3081                 if (rewrite_parents(revs, commit, rewrite_one) < 0)
3082                         return commit_error;
3083         }
3084         return action;
3085 }
3086
3087 static void track_linear(struct rev_info *revs, struct commit *commit)
3088 {
3089         if (revs->track_first_time) {
3090                 revs->linear = 1;
3091                 revs->track_first_time = 0;
3092         } else {
3093                 struct commit_list *p;
3094                 for (p = revs->previous_parents; p; p = p->next)
3095                         if (p->item == NULL || /* first commit */
3096                             !hashcmp(p->item->object.sha1, commit->object.sha1))
3097                                 break;
3098                 revs->linear = p != NULL;
3099         }
3100         if (revs->reverse) {
3101                 if (revs->linear)
3102                         commit->object.flags |= TRACK_LINEAR;
3103         }
3104         free_commit_list(revs->previous_parents);
3105         revs->previous_parents = copy_commit_list(commit->parents);
3106 }
3107
3108 static struct commit *get_revision_1(struct rev_info *revs)
3109 {
3110         if (!revs->commits)
3111                 return NULL;
3112
3113         do {
3114                 struct commit_list *entry = revs->commits;
3115                 struct commit *commit = entry->item;
3116
3117                 revs->commits = entry->next;
3118                 free(entry);
3119
3120                 if (revs->reflog_info) {
3121                         save_parents(revs, commit);
3122                         fake_reflog_parent(revs->reflog_info, commit);
3123                         commit->object.flags &= ~(ADDED | SEEN | SHOWN);
3124                 }
3125
3126                 /*
3127                  * If we haven't done the list limiting, we need to look at
3128                  * the parents here. We also need to do the date-based limiting
3129                  * that we'd otherwise have done in limit_list().
3130                  */
3131                 if (!revs->limited) {
3132                         if (revs->max_age != -1 &&
3133                             (commit->date < revs->max_age))
3134                                 continue;
3135                         if (add_parents_to_list(revs, commit, &revs->commits, NULL) < 0) {
3136                                 if (!revs->ignore_missing_links)
3137                                         die("Failed to traverse parents of commit %s",
3138                                                 sha1_to_hex(commit->object.sha1));
3139                         }
3140                 }
3141
3142                 switch (simplify_commit(revs, commit)) {
3143                 case commit_ignore:
3144                         continue;
3145                 case commit_error:
3146                         die("Failed to simplify parents of commit %s",
3147                             sha1_to_hex(commit->object.sha1));
3148                 default:
3149                         if (revs->track_linear)
3150                                 track_linear(revs, commit);
3151                         return commit;
3152                 }
3153         } while (revs->commits);
3154         return NULL;
3155 }
3156
3157 /*
3158  * Return true for entries that have not yet been shown.  (This is an
3159  * object_array_each_func_t.)
3160  */
3161 static int entry_unshown(struct object_array_entry *entry, void *cb_data_unused)
3162 {
3163         return !(entry->item->flags & SHOWN);
3164 }
3165
3166 /*
3167  * If array is on the verge of a realloc, garbage-collect any entries
3168  * that have already been shown to try to free up some space.
3169  */
3170 static void gc_boundary(struct object_array *array)
3171 {
3172         if (array->nr == array->alloc)
3173                 object_array_filter(array, entry_unshown, NULL);
3174 }
3175
3176 static void create_boundary_commit_list(struct rev_info *revs)
3177 {
3178         unsigned i;
3179         struct commit *c;
3180         struct object_array *array = &revs->boundary_commits;
3181         struct object_array_entry *objects = array->objects;
3182
3183         /*
3184          * If revs->commits is non-NULL at this point, an error occurred in
3185          * get_revision_1().  Ignore the error and continue printing the
3186          * boundary commits anyway.  (This is what the code has always
3187          * done.)
3188          */
3189         if (revs->commits) {
3190                 free_commit_list(revs->commits);
3191                 revs->commits = NULL;
3192         }
3193
3194         /*
3195          * Put all of the actual boundary commits from revs->boundary_commits
3196          * into revs->commits
3197          */
3198         for (i = 0; i < array->nr; i++) {
3199                 c = (struct commit *)(objects[i].item);
3200                 if (!c)
3201                         continue;
3202                 if (!(c->object.flags & CHILD_SHOWN))
3203                         continue;
3204                 if (c->object.flags & (SHOWN | BOUNDARY))
3205                         continue;
3206                 c->object.flags |= BOUNDARY;
3207                 commit_list_insert(c, &revs->commits);
3208         }
3209
3210         /*
3211          * If revs->topo_order is set, sort the boundary commits
3212          * in topological order
3213          */
3214         sort_in_topological_order(&revs->commits, revs->sort_order);
3215 }
3216
3217 static struct commit *get_revision_internal(struct rev_info *revs)
3218 {
3219         struct commit *c = NULL;
3220         struct commit_list *l;
3221
3222         if (revs->boundary == 2) {
3223                 /*
3224                  * All of the normal commits have already been returned,
3225                  * and we are now returning boundary commits.
3226                  * create_boundary_commit_list() has populated
3227                  * revs->commits with the remaining commits to return.
3228                  */
3229                 c = pop_commit(&revs->commits);
3230                 if (c)
3231                         c->object.flags |= SHOWN;
3232                 return c;
3233         }
3234
3235         /*
3236          * If our max_count counter has reached zero, then we are done. We
3237          * don't simply return NULL because we still might need to show
3238          * boundary commits. But we want to avoid calling get_revision_1, which
3239          * might do a considerable amount of work finding the next commit only
3240          * for us to throw it away.
3241          *
3242          * If it is non-zero, then either we don't have a max_count at all
3243          * (-1), or it is still counting, in which case we decrement.
3244          */
3245         if (revs->max_count) {
3246                 c = get_revision_1(revs);
3247                 if (c) {
3248                         while (revs->skip_count > 0) {
3249                                 revs->skip_count--;
3250                                 c = get_revision_1(revs);
3251                                 if (!c)
3252                                         break;
3253                         }
3254                 }
3255
3256                 if (revs->max_count > 0)
3257                         revs->max_count--;
3258         }
3259
3260         if (c)
3261                 c->object.flags |= SHOWN;
3262
3263         if (!revs->boundary)
3264                 return c;
3265
3266         if (!c) {
3267                 /*
3268                  * get_revision_1() runs out the commits, and
3269                  * we are done computing the boundaries.
3270                  * switch to boundary commits output mode.
3271                  */
3272                 revs->boundary = 2;
3273
3274                 /*
3275                  * Update revs->commits to contain the list of
3276                  * boundary commits.
3277                  */
3278                 create_boundary_commit_list(revs);
3279
3280                 return get_revision_internal(revs);
3281         }
3282
3283         /*
3284          * boundary commits are the commits that are parents of the
3285          * ones we got from get_revision_1() but they themselves are
3286          * not returned from get_revision_1().  Before returning
3287          * 'c', we need to mark its parents that they could be boundaries.
3288          */
3289
3290         for (l = c->parents; l; l = l->next) {
3291                 struct object *p;
3292                 p = &(l->item->object);
3293                 if (p->flags & (CHILD_SHOWN | SHOWN))
3294                         continue;
3295                 p->flags |= CHILD_SHOWN;
3296                 gc_boundary(&revs->boundary_commits);
3297                 add_object_array(p, NULL, &revs->boundary_commits);
3298         }
3299
3300         return c;
3301 }
3302
3303 struct commit *get_revision(struct rev_info *revs)
3304 {
3305         struct commit *c;
3306         struct commit_list *reversed;
3307
3308         if (revs->reverse) {
3309                 reversed = NULL;
3310                 while ((c = get_revision_internal(revs)))
3311                         commit_list_insert(c, &reversed);
3312                 revs->commits = reversed;
3313                 revs->reverse = 0;
3314                 revs->reverse_output_stage = 1;
3315         }
3316
3317         if (revs->reverse_output_stage) {
3318                 c = pop_commit(&revs->commits);
3319                 if (revs->track_linear)
3320                         revs->linear = !!(c && c->object.flags & TRACK_LINEAR);
3321                 return c;
3322         }
3323
3324         c = get_revision_internal(revs);
3325         if (c && revs->graph)
3326                 graph_update(revs->graph, c);
3327         if (!c) {
3328                 free_saved_parents(revs);
3329                 if (revs->previous_parents) {
3330                         free_commit_list(revs->previous_parents);
3331                         revs->previous_parents = NULL;
3332                 }
3333         }
3334         return c;
3335 }
3336
3337 char *get_revision_mark(const struct rev_info *revs, const struct commit *commit)
3338 {
3339         if (commit->object.flags & BOUNDARY)
3340                 return "-";
3341         else if (commit->object.flags & UNINTERESTING)
3342                 return "^";
3343         else if (commit->object.flags & PATCHSAME)
3344                 return "=";
3345         else if (!revs || revs->left_right) {
3346                 if (commit->object.flags & SYMMETRIC_LEFT)
3347                         return "<";
3348                 else
3349                         return ">";
3350         } else if (revs->graph)
3351                 return "*";
3352         else if (revs->cherry_mark)
3353                 return "+";
3354         return "";
3355 }
3356
3357 void put_revision_mark(const struct rev_info *revs, const struct commit *commit)
3358 {
3359         char *mark = get_revision_mark(revs, commit);
3360         if (!strlen(mark))
3361                 return;
3362         fputs(mark, stdout);
3363         putchar(' ');
3364 }