'tag -l' and 'branch -l' have two different ways of finding
out if a certain ref contains a commit. Implement both these
methods in ref-filter and give the caller of ref-filter API
the option to pick which implementation to be used.
'branch -l' uses 'is_descendant_of()' from commit.c which is
left as the default implementation to be used.
'tag -l' uses a more specific algorithm since ffc4b80. This
implementation is used whenever the 'with_commit_tag_algo' bit
is set in 'struct ref_filter'.
Mentored-by: Christian Couder <christian.couder@xxxxxxxxx>
Mentored-by: Matthieu Moy <matthieu.moy@xxxxxxxxxxxxxxx>
Signed-off-by: Karthik Nayak <karthik.188@xxxxxxxxx>
---
ref-filter.c | 114 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
ref-filter.h | 3 ++
2 files changed, 116 insertions(+), 1 deletion(-)
diff --git a/ref-filter.c b/ref-filter.c
index 2f20cb3..f793386 100644
--- a/ref-filter.c
+++ b/ref-filter.c
@@ -818,6 +818,114 @@ static void get_ref_atom_value(struct ref_array_item *ref, int atom, struct atom
*v = &ref->value[atom];
}
+enum contains_result {
+ CONTAINS_UNKNOWN = -1,
+ CONTAINS_NO = 0,
+ CONTAINS_YES = 1
+};
+
+/*
+ * Mimicking the real stack, this stack lives on the heap, avoiding stack
+ * overflows.
+ *
+ * At each recursion step, the stack items points to the commits whose
+ * ancestors are to be inspected.
+ */
+struct contains_stack {
+ int nr, alloc;
+ struct contains_stack_entry {
+ struct commit *commit;
+ struct commit_list *parents;
+ } *contains_stack;
+};
+
+static int in_commit_list(const struct commit_list *want, struct commit *c)
+{
+ for (; want; want = want->next)
+ if (!hashcmp(want->item->object.sha1, c->object.sha1))
+ return 1;
+ return 0;
+}
+
+/*
+ * Test whether the candidate or one of its parents is contained in the list.
+ * Do not recurse to find out, though, but return -1 if inconclusive.
+ */
+static enum contains_result contains_test(struct commit *candidate,
+ const struct commit_list *want)
+{
+ /* was it previously marked as containing a want commit? */
+ if (candidate->object.flags & TMP_MARK)
+ return 1;
+ /* or marked as not possibly containing a want commit? */
+ if (candidate->object.flags & UNINTERESTING)
+ return 0;
+ /* or are we it? */
+ if (in_commit_list(want, candidate)) {
+ candidate->object.flags |= TMP_MARK;
+ return 1;
+ }
+
+ if (parse_commit(candidate) < 0)
+ return 0;
+
+ return -1;
+}
+
+static void push_to_contains_stack(struct commit *candidate, struct contains_stack *contains_stack)
+{
+ ALLOC_GROW(contains_stack->contains_stack, contains_stack->nr + 1, contains_stack->alloc);
+ contains_stack->contains_stack[contains_stack->nr].commit = candidate;
+ contains_stack->contains_stack[contains_stack->nr++].parents = candidate->parents;
+}
+
+static enum contains_result contains_tag_algo(struct commit *candidate,
+ const struct commit_list *want)
+{
+ struct contains_stack contains_stack = { 0, 0, NULL };
+ int result = contains_test(candidate, want);
+
+ if (result != CONTAINS_UNKNOWN)
+ return result;
+
+ push_to_contains_stack(candidate, &contains_stack);
+ while (contains_stack.nr) {
+ struct contains_stack_entry *entry = &contains_stack.contains_stack[contains_stack.nr - 1];
+ struct commit *commit = entry->commit;
+ struct commit_list *parents = entry->parents;
+
+ if (!parents) {
+ commit->object.flags |= UNINTERESTING;
+ contains_stack.nr--;
+ }
+ /*
+ * If we just popped the stack, parents->item has been marked,
+ * therefore contains_test will return a meaningful 0 or 1.
+ */
+ else switch (contains_test(parents->item, want)) {
+ case CONTAINS_YES:
+ commit->object.flags |= TMP_MARK;
+ contains_stack.nr--;
+ break;
+ case CONTAINS_NO:
+ entry->parents = parents->next;
+ break;
+ case CONTAINS_UNKNOWN:
+ push_to_contains_stack(parents->item, &contains_stack);
+ break;
+ }
+ }
+ free(contains_stack.contains_stack);
+ return contains_test(candidate, want);
+}
+
+static int commit_contains(struct ref_filter *filter, struct commit *commit)
+{
+ if (filter->with_commit_tag_algo)
+ return contains_tag_algo(commit, filter->with_commit);
+ return is_descendant_of(commit, filter->with_commit);
+}
+
/*
* Return 1 if the refname matches one of the patterns, otherwise 0.
* A pattern can be path prefix (e.g. a refname "refs/heads/master"
@@ -908,10 +1016,14 @@ static int ref_filter_handler(const char *refname, const struct object_id *oid,
* obtain the commit using the 'oid' available and discard all
* non-commits early. The actual filtering is done later.
*/
- if (filter->merge_commit) {
+ if (filter->merge_commit || filter->with_commit) {
commit = lookup_commit_reference_gently(oid->hash, 1);
if (!commit)
return 0;
+ /* We perform the filtering for the '--contains' option */
+ if (filter->with_commit &&
+ !commit_contains(filter, commit))
+ return 0;
}
/*
diff --git a/ref-filter.h b/ref-filter.h
index 7241a1d..3c59431 100644
--- a/ref-filter.h
+++ b/ref-filter.h
@@ -44,6 +44,7 @@ struct ref_array {
struct ref_filter {
const char **name_patterns;
struct sha1_array points_at;
+ struct commit_list *with_commit;
enum {
REF_FILTER_MERGED_NONE = 0,
@@ -51,6 +52,8 @@ struct ref_filter {
REF_FILTER_MERGED_OMIT
} merge;
struct commit *merge_commit;
+
+ unsigned int with_commit_tag_algo: 1;
};
struct ref_filter_cbdata {
--
2.4.4
--
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