зеркало из https://github.com/microsoft/git.git
move get_merge_bases() to core lib.
Signed-off-by: Junio C Hamano <junkio@cox.net>
This commit is contained in:
Johannes Schindelin
Junio C Hamano
Родитель
52cab8a084
Коммит
7c6f8aaf6d
240
commit.c
240
commit.c
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@ -846,3 +846,243 @@ void sort_in_topological_order_fn(struct commit_list ** list, int lifo,
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}
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free(nodes);
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}
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/* merge-rebase stuff */
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#define PARENT1 1
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#define PARENT2 2
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#define UNINTERESTING 4
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static struct commit *interesting(struct commit_list *list)
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{
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while (list) {
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struct commit *commit = list->item;
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list = list->next;
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if (commit->object.flags & UNINTERESTING)
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continue;
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return commit;
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}
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return NULL;
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}
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/*
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* A pathological example of how this thing works.
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*
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* Suppose we had this commit graph, where chronologically
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* the timestamp on the commit are A <= B <= C <= D <= E <= F
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* and we are trying to figure out the merge base for E and F
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* commits.
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*
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* F
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* / \
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* E A D
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* \ / /
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* B /
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* \ /
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* C
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*
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* First we push E and F to list to be processed. E gets bit 1
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* and F gets bit 2. The list becomes:
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*
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* list=F(2) E(1), result=empty
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*
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* Then we pop F, the newest commit, from the list. Its flag is 2.
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* We scan its parents, mark them reachable from the side that F is
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* reachable from, and push them to the list:
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*
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* list=E(1) D(2) A(2), result=empty
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*
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* Next pop E and do the same.
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*
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* list=D(2) B(1) A(2), result=empty
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*
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* Next pop D and do the same.
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*
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* list=C(2) B(1) A(2), result=empty
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*
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* Next pop C and do the same.
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*
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* list=B(1) A(2), result=empty
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*
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* Now it is B's turn. We mark its parent, C, reachable from B's side,
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* and push it to the list:
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*
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* list=C(3) A(2), result=empty
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*
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* Now pop C and notice it has flags==3. It is placed on the result list,
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* and the list now contains:
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*
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* list=A(2), result=C(3)
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*
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* We pop A and do the same.
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*
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* list=B(3), result=C(3)
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*
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* Next, we pop B and something very interesting happens. It has flags==3
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* so it is also placed on the result list, and its parents are marked
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* uninteresting, retroactively, and placed back on the list:
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*
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* list=C(7), result=C(7) B(3)
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*
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* Now, list does not have any interesting commit. So we find the newest
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* commit from the result list that is not marked uninteresting. Which is
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* commit B.
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*
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*
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* Another pathological example how this thing used to fail to mark an
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* ancestor of a merge base as UNINTERESTING before we introduced the
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* postprocessing phase (mark_reachable_commits).
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*
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* 2
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* H
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* 1 / \
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* G A \
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* |\ / \
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* | B \
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* | \ \
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* \ C F
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* \ \ /
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* \ D /
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* \ | /
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* \| /
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* E
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*
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* list A B C D E F G H
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* G1 H2 - - - - - - 1 2
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* H2 E1 B1 - 1 - - 1 - 1 2
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* F2 E1 B1 A2 2 1 - - 1 2 1 2
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* E3 B1 A2 2 1 - - 3 2 1 2
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* B1 A2 2 1 - - 3 2 1 2
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* C1 A2 2 1 1 - 3 2 1 2
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* D1 A2 2 1 1 1 3 2 1 2
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* A2 2 1 1 1 3 2 1 2
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* B3 2 3 1 1 3 2 1 2
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* C7 2 3 7 1 3 2 1 2
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*
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* At this point, unfortunately, everybody in the list is
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* uninteresting, so we fail to complete the following two
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* steps to fully marking uninteresting commits.
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*
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* D7 2 3 7 7 3 2 1 2
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* E7 2 3 7 7 7 2 1 2
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*
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* and we ended up showing E as an interesting merge base.
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* The postprocessing phase re-injects C and continues traversal
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* to contaminate D and E.
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*/
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static void mark_reachable_commits(struct commit_list *result,
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struct commit_list *list)
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{
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struct commit_list *tmp;
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/*
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* Postprocess to fully contaminate the well.
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*/
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for (tmp = result; tmp; tmp = tmp->next) {
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struct commit *c = tmp->item;
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/* Reinject uninteresting ones to list,
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* so we can scan their parents.
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*/
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if (c->object.flags & UNINTERESTING)
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commit_list_insert(c, &list);
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}
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while (list) {
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struct commit *c = list->item;
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struct commit_list *parents;
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tmp = list;
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list = list->next;
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free(tmp);
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/* Anything taken out of the list is uninteresting, so
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* mark all its parents uninteresting. We do not
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* parse new ones (we already parsed all the relevant
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* ones).
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*/
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parents = c->parents;
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while (parents) {
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struct commit *p = parents->item;
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parents = parents->next;
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if (!(p->object.flags & UNINTERESTING)) {
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p->object.flags |= UNINTERESTING;
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commit_list_insert(p, &list);
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}
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}
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}
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}
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struct commit_list *get_merge_bases(struct commit *rev1, struct commit *rev2)
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{
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struct commit_list *list = NULL;
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struct commit_list *result = NULL;
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struct commit_list *tmp = NULL;
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if (rev1 == rev2)
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return commit_list_insert(rev1, &result);
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parse_commit(rev1);
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parse_commit(rev2);
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rev1->object.flags |= PARENT1;
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rev2->object.flags |= PARENT2;
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insert_by_date(rev1, &list);
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insert_by_date(rev2, &list);
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while (interesting(list)) {
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struct commit *commit = list->item;
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struct commit_list *parents;
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int flags = commit->object.flags
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& (PARENT1 | PARENT2 | UNINTERESTING);
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tmp = list;
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list = list->next;
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free(tmp);
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if (flags == (PARENT1 | PARENT2)) {
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insert_by_date(commit, &result);
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/* Mark parents of a found merge uninteresting */
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flags |= UNINTERESTING;
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}
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parents = commit->parents;
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while (parents) {
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struct commit *p = parents->item;
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parents = parents->next;
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if ((p->object.flags & flags) == flags)
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continue;
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parse_commit(p);
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p->object.flags |= flags;
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insert_by_date(p, &list);
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}
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}
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if (!result)
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return NULL;
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if (result->next && list)
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mark_reachable_commits(result, list);
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/* cull duplicates */
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for (tmp = result, list = NULL; tmp; ) {
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struct commit *commit = tmp->item;
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struct commit_list *next = tmp->next;
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if (commit->object.flags & UNINTERESTING) {
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if (list != NULL)
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list->next = next;
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free(tmp);
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} else {
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if (list == NULL)
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result = tmp;
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list = tmp;
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commit->object.flags |= UNINTERESTING;
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}
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tmp = next;
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}
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/* reset flags */
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clear_commit_marks(rev1, PARENT1 | PARENT2 | UNINTERESTING);
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clear_commit_marks(rev2, PARENT1 | PARENT2 | UNINTERESTING);
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return result;
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}
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2
commit.h
2
commit.h
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@ -105,4 +105,6 @@ struct commit_graft *read_graft_line(char *buf, int len);
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int register_commit_graft(struct commit_graft *, int);
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int read_graft_file(const char *graft_file);
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extern struct commit_list *get_merge_bases(struct commit *rev1, struct commit *rev2);
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#endif /* COMMIT_H */
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238
merge-base.c
238
merge-base.c
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@ -2,244 +2,6 @@
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#include "cache.h"
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#include "commit.h"
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#define PARENT1 1
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#define PARENT2 2
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#define UNINTERESTING 4
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static struct commit *interesting(struct commit_list *list)
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{
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while (list) {
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struct commit *commit = list->item;
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list = list->next;
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if (commit->object.flags & UNINTERESTING)
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continue;
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return commit;
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}
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return NULL;
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}
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/*
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* A pathological example of how this thing works.
|
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*
|
||||
* Suppose we had this commit graph, where chronologically
|
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* the timestamp on the commit are A <= B <= C <= D <= E <= F
|
||||
* and we are trying to figure out the merge base for E and F
|
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* commits.
|
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*
|
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* F
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* / \
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* E A D
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* \ / /
|
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* B /
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* \ /
|
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* C
|
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*
|
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* First we push E and F to list to be processed. E gets bit 1
|
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* and F gets bit 2. The list becomes:
|
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*
|
||||
* list=F(2) E(1), result=empty
|
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*
|
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* Then we pop F, the newest commit, from the list. Its flag is 2.
|
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* We scan its parents, mark them reachable from the side that F is
|
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* reachable from, and push them to the list:
|
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*
|
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* list=E(1) D(2) A(2), result=empty
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*
|
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* Next pop E and do the same.
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*
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* list=D(2) B(1) A(2), result=empty
|
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*
|
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* Next pop D and do the same.
|
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*
|
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* list=C(2) B(1) A(2), result=empty
|
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*
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* Next pop C and do the same.
|
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*
|
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* list=B(1) A(2), result=empty
|
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*
|
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* Now it is B's turn. We mark its parent, C, reachable from B's side,
|
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* and push it to the list:
|
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*
|
||||
* list=C(3) A(2), result=empty
|
||||
*
|
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* Now pop C and notice it has flags==3. It is placed on the result list,
|
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* and the list now contains:
|
||||
*
|
||||
* list=A(2), result=C(3)
|
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*
|
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* We pop A and do the same.
|
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*
|
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* list=B(3), result=C(3)
|
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*
|
||||
* Next, we pop B and something very interesting happens. It has flags==3
|
||||
* so it is also placed on the result list, and its parents are marked
|
||||
* uninteresting, retroactively, and placed back on the list:
|
||||
*
|
||||
* list=C(7), result=C(7) B(3)
|
||||
*
|
||||
* Now, list does not have any interesting commit. So we find the newest
|
||||
* commit from the result list that is not marked uninteresting. Which is
|
||||
* commit B.
|
||||
*
|
||||
*
|
||||
* Another pathological example how this thing used to fail to mark an
|
||||
* ancestor of a merge base as UNINTERESTING before we introduced the
|
||||
* postprocessing phase (mark_reachable_commits).
|
||||
*
|
||||
* 2
|
||||
* H
|
||||
* 1 / \
|
||||
* G A \
|
||||
* |\ / \
|
||||
* | B \
|
||||
* | \ \
|
||||
* \ C F
|
||||
* \ \ /
|
||||
* \ D /
|
||||
* \ | /
|
||||
* \| /
|
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* E
|
||||
*
|
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* list A B C D E F G H
|
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* G1 H2 - - - - - - 1 2
|
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* H2 E1 B1 - 1 - - 1 - 1 2
|
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* F2 E1 B1 A2 2 1 - - 1 2 1 2
|
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* E3 B1 A2 2 1 - - 3 2 1 2
|
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* B1 A2 2 1 - - 3 2 1 2
|
||||
* C1 A2 2 1 1 - 3 2 1 2
|
||||
* D1 A2 2 1 1 1 3 2 1 2
|
||||
* A2 2 1 1 1 3 2 1 2
|
||||
* B3 2 3 1 1 3 2 1 2
|
||||
* C7 2 3 7 1 3 2 1 2
|
||||
*
|
||||
* At this point, unfortunately, everybody in the list is
|
||||
* uninteresting, so we fail to complete the following two
|
||||
* steps to fully marking uninteresting commits.
|
||||
*
|
||||
* D7 2 3 7 7 3 2 1 2
|
||||
* E7 2 3 7 7 7 2 1 2
|
||||
*
|
||||
* and we ended up showing E as an interesting merge base.
|
||||
* The postprocessing phase re-injects C and continues traversal
|
||||
* to contaminate D and E.
|
||||
*/
|
||||
|
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static void mark_reachable_commits(struct commit_list *result,
|
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struct commit_list *list)
|
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{
|
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struct commit_list *tmp;
|
||||
|
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/*
|
||||
* Postprocess to fully contaminate the well.
|
||||
*/
|
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for (tmp = result; tmp; tmp = tmp->next) {
|
||||
struct commit *c = tmp->item;
|
||||
/* Reinject uninteresting ones to list,
|
||||
* so we can scan their parents.
|
||||
*/
|
||||
if (c->object.flags & UNINTERESTING)
|
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commit_list_insert(c, &list);
|
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}
|
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while (list) {
|
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struct commit *c = list->item;
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struct commit_list *parents;
|
||||
|
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tmp = list;
|
||||
list = list->next;
|
||||
free(tmp);
|
||||
|
||||
/* Anything taken out of the list is uninteresting, so
|
||||
* mark all its parents uninteresting. We do not
|
||||
* parse new ones (we already parsed all the relevant
|
||||
* ones).
|
||||
*/
|
||||
parents = c->parents;
|
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while (parents) {
|
||||
struct commit *p = parents->item;
|
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parents = parents->next;
|
||||
if (!(p->object.flags & UNINTERESTING)) {
|
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p->object.flags |= UNINTERESTING;
|
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commit_list_insert(p, &list);
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
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struct commit_list *get_merge_bases(struct commit *rev1, struct commit *rev2)
|
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{
|
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struct commit_list *list = NULL;
|
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struct commit_list *result = NULL;
|
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struct commit_list *tmp = NULL;
|
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|
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if (rev1 == rev2)
|
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return commit_list_insert(rev1, &result);
|
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|
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parse_commit(rev1);
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||||
parse_commit(rev2);
|
||||
|
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rev1->object.flags |= PARENT1;
|
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rev2->object.flags |= PARENT2;
|
||||
insert_by_date(rev1, &list);
|
||||
insert_by_date(rev2, &list);
|
||||
|
||||
while (interesting(list)) {
|
||||
struct commit *commit = list->item;
|
||||
struct commit_list *parents;
|
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int flags = commit->object.flags
|
||||
& (PARENT1 | PARENT2 | UNINTERESTING);
|
||||
|
||||
tmp = list;
|
||||
list = list->next;
|
||||
free(tmp);
|
||||
if (flags == (PARENT1 | PARENT2)) {
|
||||
insert_by_date(commit, &result);
|
||||
|
||||
/* Mark parents of a found merge uninteresting */
|
||||
flags |= UNINTERESTING;
|
||||
}
|
||||
parents = commit->parents;
|
||||
while (parents) {
|
||||
struct commit *p = parents->item;
|
||||
parents = parents->next;
|
||||
if ((p->object.flags & flags) == flags)
|
||||
continue;
|
||||
parse_commit(p);
|
||||
p->object.flags |= flags;
|
||||
insert_by_date(p, &list);
|
||||
}
|
||||
}
|
||||
|
||||
if (!result)
|
||||
return NULL;
|
||||
|
||||
if (result->next && list)
|
||||
mark_reachable_commits(result, list);
|
||||
|
||||
/* cull duplicates */
|
||||
for (tmp = result, list = NULL; tmp; ) {
|
||||
struct commit *commit = tmp->item;
|
||||
struct commit_list *next = tmp->next;
|
||||
if (commit->object.flags & UNINTERESTING) {
|
||||
if (list != NULL)
|
||||
list->next = next;
|
||||
free(tmp);
|
||||
} else {
|
||||
if (list == NULL)
|
||||
result = tmp;
|
||||
list = tmp;
|
||||
commit->object.flags |= UNINTERESTING;
|
||||
}
|
||||
|
||||
tmp = next;
|
||||
}
|
||||
|
||||
/* reset flags */
|
||||
clear_commit_marks(rev1, PARENT1 | PARENT2 | UNINTERESTING);
|
||||
clear_commit_marks(rev2, PARENT1 | PARENT2 | UNINTERESTING);
|
||||
|
||||
return result;
|
||||
}
|
||||
|
||||
static int show_all = 0;
|
||||
|
||||
static int merge_base(struct commit *rev1, struct commit *rev2)
|
||||
|
|
|
|||
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Ссылка в новой задаче