From f37d3c755209234acfc2ca280027ebdab8e9ea8a Mon Sep 17 00:00:00 2001 From: Junio C Hamano Date: Thu, 30 Aug 2012 23:20:40 -0700 Subject: [PATCH] reduce_heads(): reimplement on top of remove_redundant() This is used by "git merge" and "git merge-base --independent" but used to use a similar N*(N-1) traversals to reject commits that are ancestors of other commits. Reimplement it on top of remove_redundant(). Note that the callers of this function are allowed to pass the same commit more than once, but remove_redundant() is designed to be fed each commit only once. The function removes duplicates before calling remove_redundant(). Signed-off-by: Junio C Hamano --- commit.c | 56 ++++++++++++++++++-------------------------------------- 1 file changed, 18 insertions(+), 38 deletions(-) diff --git a/commit.c b/commit.c index 2ff5061c1..69af37014 100644 --- a/commit.c +++ b/commit.c @@ -842,51 +842,31 @@ struct commit_list *reduce_heads(struct commit_list *heads) { struct commit_list *p; struct commit_list *result = NULL, **tail = &result; - struct commit **other; - size_t num_head, num_other; + struct commit **array; + int num_head, i; if (!heads) return NULL; - /* Avoid unnecessary reallocations */ - for (p = heads, num_head = 0; p; p = p->next) - num_head++; - other = xcalloc(sizeof(*other), num_head); - - /* For each commit, see if it can be reached by others */ - for (p = heads; p; p = p->next) { - struct commit_list *q, *base; - - /* Do we already have this in the result? */ - for (q = result; q; q = q->next) - if (p->item == q->item) - break; - if (q) + /* Uniquify */ + for (p = heads; p; p = p->next) + p->item->object.flags &= ~STALE; + for (p = heads, num_head = 0; p; p = p->next) { + if (p->item->object.flags & STALE) continue; - - num_other = 0; - for (q = heads; q; q = q->next) { - if (p->item == q->item) - continue; - other[num_other++] = q->item; + p->item->object.flags |= STALE; + num_head++; + } + array = xcalloc(sizeof(*array), num_head); + for (p = heads, i = 0; p; p = p->next) { + if (p->item->object.flags & STALE) { + array[i++] = p->item; + p->item->object.flags &= ~STALE; } - if (num_other) - base = get_merge_bases_many(p->item, num_other, other, 1); - else - base = NULL; - /* - * If p->item does not have anything common with other - * commits, there won't be any merge base. If it is - * reachable from some of the others, p->item will be - * the merge base. If its history is connected with - * others, but p->item is not reachable by others, we - * will get something other than p->item back. - */ - if (!base || (base->item != p->item)) - tail = &(commit_list_insert(p->item, tail)->next); - free_commit_list(base); } - free(other); + num_head = remove_redundant(array, num_head); + for (i = 0; i < num_head; i++) + tail = &commit_list_insert(array[i], tail)->next; return result; } -- 2.26.2