+#define SEEN (1u << 0)
+#define INTERESTING (1u << 1)
+#define COUNTED (1u << 2)
+#define SHOWN (1u << 3)
+#define TREECHANGE (1u << 4)
+
+static const char rev_list_usage[] =
+"git-rev-list [OPTION] <commit-id>... [ -- paths... ]\n"
+" limiting output:\n"
+" --max-count=nr\n"
+" --max-age=epoch\n"
+" --min-age=epoch\n"
+" --sparse\n"
+" --no-merges\n"
+" --all\n"
+" ordering output:\n"
+" --merge-order [ --show-breaks ]\n"
+" --topo-order\n"
+" formatting output:\n"
+" --parents\n"
+" --objects\n"
+" --unpacked\n"
+" --header | --pretty\n"
+" special purpose:\n"
+" --bisect"
+;
+
+static int dense = 1;
+static int unpacked = 0;
+static int bisect_list = 0;
+static int tag_objects = 0;
+static int tree_objects = 0;
+static int blob_objects = 0;
+static int verbose_header = 0;
+static int show_parents = 0;
+static int hdr_termination = 0;
+static const char *commit_prefix = "";
+static unsigned long max_age = -1;
+static unsigned long min_age = -1;
+static int max_count = -1;
+static enum cmit_fmt commit_format = CMIT_FMT_RAW;
+static int merge_order = 0;
+static int show_breaks = 0;
+static int stop_traversal = 0;
+static int topo_order = 0;
+static int no_merges = 0;
+static const char **paths = NULL;
+
+static void show_commit(struct commit *commit)
+{
+ commit->object.flags |= SHOWN;
+ if (show_breaks) {
+ commit_prefix = "| ";
+ if (commit->object.flags & DISCONTINUITY) {
+ commit_prefix = "^ ";
+ } else if (commit->object.flags & BOUNDARY) {
+ commit_prefix = "= ";
+ }
+ }
+ printf("%s%s", commit_prefix, sha1_to_hex(commit->object.sha1));
+ if (show_parents) {
+ struct commit_list *parents = commit->parents;
+ while (parents) {
+ printf(" %s", sha1_to_hex(parents->item->object.sha1));
+ parents = parents->next;
+ }
+ }
+ if (commit_format == CMIT_FMT_ONELINE)
+ putchar(' ');
+ else
+ putchar('\n');
+
+ if (verbose_header) {
+ static char pretty_header[16384];
+ pretty_print_commit(commit_format, commit->buffer, ~0, pretty_header, sizeof(pretty_header));
+ printf("%s%c", pretty_header, hdr_termination);
+ }
+ fflush(stdout);
+}
+
+static int rewrite_one(struct commit **pp)
+{
+ for (;;) {
+ struct commit *p = *pp;
+ if (p->object.flags & (TREECHANGE | UNINTERESTING))
+ return 0;
+ if (!p->parents)
+ return -1;
+ *pp = p->parents->item;
+ }
+}
+
+static void rewrite_parents(struct commit *commit)
+{
+ struct commit_list **pp = &commit->parents;
+ while (*pp) {
+ struct commit_list *parent = *pp;
+ if (rewrite_one(&parent->item) < 0) {
+ *pp = parent->next;
+ continue;
+ }
+ pp = &parent->next;
+ }
+}
+
+static int filter_commit(struct commit * commit)
+{
+ if (stop_traversal && (commit->object.flags & BOUNDARY))
+ return STOP;
+ if (commit->object.flags & (UNINTERESTING|SHOWN))
+ return CONTINUE;
+ if (min_age != -1 && (commit->date > min_age))
+ return CONTINUE;
+ if (max_age != -1 && (commit->date < max_age)) {
+ stop_traversal=1;
+ return CONTINUE;
+ }
+ if (no_merges && (commit->parents && commit->parents->next))
+ return CONTINUE;
+ if (paths && dense) {
+ if (!(commit->object.flags & TREECHANGE))
+ return CONTINUE;
+ rewrite_parents(commit);
+ }
+ return DO;
+}
+
+static int process_commit(struct commit * commit)
+{
+ int action=filter_commit(commit);
+
+ if (action == STOP) {
+ return STOP;
+ }
+
+ if (action == CONTINUE) {
+ return CONTINUE;
+ }
+
+ if (max_count != -1 && !max_count--)
+ return STOP;
+
+ show_commit(commit);
+
+ return CONTINUE;
+}
+
+static struct object_list **add_object(struct object *obj, struct object_list **p, const char *name)
+{
+ struct object_list *entry = xmalloc(sizeof(*entry));
+ entry->item = obj;
+ entry->next = *p;
+ entry->name = name;
+ *p = entry;
+ return &entry->next;
+}
+
+static struct object_list **process_blob(struct blob *blob, struct object_list **p, const char *name)
+{
+ struct object *obj = &blob->object;
+
+ if (!blob_objects)
+ return p;
+ if (obj->flags & (UNINTERESTING | SEEN))
+ return p;
+ obj->flags |= SEEN;
+ return add_object(obj, p, name);
+}
+
+static struct object_list **process_tree(struct tree *tree, struct object_list **p, const char *name)
+{
+ struct object *obj = &tree->object;
+ struct tree_entry_list *entry;
+
+ if (!tree_objects)
+ return p;
+ if (obj->flags & (UNINTERESTING | SEEN))
+ return p;
+ if (parse_tree(tree) < 0)
+ die("bad tree object %s", sha1_to_hex(obj->sha1));
+ obj->flags |= SEEN;
+ p = add_object(obj, p, name);
+ entry = tree->entries;
+ tree->entries = NULL;
+ while (entry) {
+ struct tree_entry_list *next = entry->next;
+ if (entry->directory)
+ p = process_tree(entry->item.tree, p, entry->name);
+ else
+ p = process_blob(entry->item.blob, p, entry->name);
+ free(entry);
+ entry = next;
+ }
+ return p;
+}
+
+static struct object_list *pending_objects = NULL;
+
+static void show_commit_list(struct commit_list *list)
+{
+ struct object_list *objects = NULL, **p = &objects, *pending;
+ while (list) {
+ struct commit *commit = pop_most_recent_commit(&list, SEEN);
+
+ p = process_tree(commit->tree, p, "");
+ if (process_commit(commit) == STOP)
+ break;
+ }
+ for (pending = pending_objects; pending; pending = pending->next) {
+ struct object *obj = pending->item;
+ const char *name = pending->name;
+ if (obj->flags & (UNINTERESTING | SEEN))
+ continue;
+ if (obj->type == tag_type) {
+ obj->flags |= SEEN;
+ p = add_object(obj, p, name);
+ continue;
+ }
+ if (obj->type == tree_type) {
+ p = process_tree((struct tree *)obj, p, name);
+ continue;
+ }
+ if (obj->type == blob_type) {
+ p = process_blob((struct blob *)obj, p, name);
+ continue;
+ }
+ die("unknown pending object %s (%s)", sha1_to_hex(obj->sha1), name);
+ }
+ while (objects) {
+ /* An object with name "foo\n0000000000000000000000000000000000000000"
+ * can be used confuse downstream git-pack-objects very badly.
+ */
+ const char *ep = strchr(objects->name, '\n');
+ if (ep) {
+ printf("%s %.*s\n", sha1_to_hex(objects->item->sha1),
+ (int) (ep - objects->name),
+ objects->name);
+ }
+ else
+ printf("%s %s\n", sha1_to_hex(objects->item->sha1), objects->name);
+ objects = objects->next;
+ }
+}
+
+static void mark_blob_uninteresting(struct blob *blob)
+{
+ if (!blob_objects)
+ return;
+ if (blob->object.flags & UNINTERESTING)
+ return;
+ blob->object.flags |= UNINTERESTING;
+}
+
+static void mark_tree_uninteresting(struct tree *tree)
+{
+ struct object *obj = &tree->object;
+ struct tree_entry_list *entry;
+
+ if (!tree_objects)
+ return;
+ if (obj->flags & UNINTERESTING)
+ return;
+ obj->flags |= UNINTERESTING;
+ if (!has_sha1_file(obj->sha1))
+ return;
+ if (parse_tree(tree) < 0)
+ die("bad tree %s", sha1_to_hex(obj->sha1));
+ entry = tree->entries;
+ tree->entries = NULL;
+ while (entry) {
+ struct tree_entry_list *next = entry->next;
+ if (entry->directory)
+ mark_tree_uninteresting(entry->item.tree);
+ else
+ mark_blob_uninteresting(entry->item.blob);
+ free(entry);
+ entry = next;
+ }
+}
+
+static void mark_parents_uninteresting(struct commit *commit)
+{
+ struct commit_list *parents = commit->parents;
+
+ while (parents) {
+ struct commit *commit = parents->item;
+ commit->object.flags |= UNINTERESTING;
+
+ /*
+ * Normally we haven't parsed the parent
+ * yet, so we won't have a parent of a parent
+ * here. However, it may turn out that we've
+ * reached this commit some other way (where it
+ * wasn't uninteresting), in which case we need
+ * to mark its parents recursively too..
+ */
+ if (commit->parents)
+ mark_parents_uninteresting(commit);
+
+ /*
+ * A missing commit is ok iff its parent is marked
+ * uninteresting.
+ *
+ * We just mark such a thing parsed, so that when
+ * it is popped next time around, we won't be trying
+ * to parse it and get an error.
+ */
+ if (!has_sha1_file(commit->object.sha1))
+ commit->object.parsed = 1;
+ parents = parents->next;
+ }
+}
+
+static int everybody_uninteresting(struct commit_list *orig)
+{
+ struct commit_list *list = orig;
+ while (list) {
+ struct commit *commit = list->item;
+ list = list->next;
+ if (commit->object.flags & UNINTERESTING)
+ continue;
+ return 0;
+ }
+ return 1;
+}
+
+/*
+ * This is a truly stupid algorithm, but it's only
+ * used for bisection, and we just don't care enough.
+ *
+ * We care just barely enough to avoid recursing for
+ * non-merge entries.
+ */
+static int count_distance(struct commit_list *entry)
+{
+ int nr = 0;
+
+ while (entry) {
+ struct commit *commit = entry->item;
+ struct commit_list *p;
+
+ if (commit->object.flags & (UNINTERESTING | COUNTED))
+ break;
+ if (!paths || (commit->object.flags & TREECHANGE))
+ nr++;
+ commit->object.flags |= COUNTED;
+ p = commit->parents;
+ entry = p;
+ if (p) {
+ p = p->next;
+ while (p) {
+ nr += count_distance(p);
+ p = p->next;
+ }
+ }
+ }
+
+ return nr;
+}
+
+static void clear_distance(struct commit_list *list)
+{
+ while (list) {
+ struct commit *commit = list->item;
+ commit->object.flags &= ~COUNTED;
+ list = list->next;
+ }
+}
+
+static struct commit_list *find_bisection(struct commit_list *list)
+{
+ int nr, closest;
+ struct commit_list *p, *best;
+
+ nr = 0;
+ p = list;
+ while (p) {
+ if (!paths || (p->item->object.flags & TREECHANGE))
+ nr++;
+ p = p->next;
+ }
+ closest = 0;
+ best = list;
+
+ for (p = list; p; p = p->next) {
+ int distance;
+
+ if (paths && !(p->item->object.flags & TREECHANGE))
+ continue;
+
+ distance = count_distance(p);
+ clear_distance(list);
+ if (nr - distance < distance)
+ distance = nr - distance;
+ if (distance > closest) {
+ best = p;
+ closest = distance;
+ }
+ }
+ if (best)
+ best->next = NULL;
+ return best;
+}
+
+static void mark_edges_uninteresting(struct commit_list *list)
+{
+ for ( ; list; list = list->next) {
+ struct commit_list *parents = list->item->parents;
+
+ for ( ; parents; parents = parents->next) {
+ struct commit *commit = parents->item;
+ if (commit->object.flags & UNINTERESTING)
+ mark_tree_uninteresting(commit->tree);
+ }
+ }
+}
+
+static int is_different = 0;
+
+static void file_add_remove(struct diff_options *options,
+ int addremove, unsigned mode,
+ const unsigned char *sha1,
+ const char *base, const char *path)
+{
+ is_different = 1;
+}
+
+static void file_change(struct diff_options *options,
+ unsigned old_mode, unsigned new_mode,
+ const unsigned char *old_sha1,
+ const unsigned char *new_sha1,
+ const char *base, const char *path)
+{
+ is_different = 1;
+}
+
+static struct diff_options diff_opt = {
+ .recursive = 1,
+ .add_remove = file_add_remove,
+ .change = file_change,
+};
+
+static int same_tree(struct tree *t1, struct tree *t2)
+{
+ is_different = 0;
+ if (diff_tree_sha1(t1->object.sha1, t2->object.sha1, "", &diff_opt) < 0)
+ return 0;
+ return !is_different;
+}
+
+static int same_tree_as_empty(struct tree *t1)