[PATCH v4 09/28] shallow.c: steps 6 and 7 to select new commits for .git/shallow
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
commit.h | 3 +
shallow.c | 295 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 298 insertions(+)
diff --git a/commit.h b/commit.h
index 9ead93b..69bca3e 100644
--- a/commit.h
+++ b/commit.h
@@ -223,6 +223,9 @@ extern void clear_shallow_info(struct shallow_info *);
extern void remove_nonexistent_theirs_shallow(struct shallow_info *);
extern void remove_nonexistent_ours_in_pack(struct shallow_info *,
struct packed_git *);
+extern void assign_shallow_commits_to_refs(struct shallow_info *info,
+ uint32_t **used,
+ int *ref_status);
int is_descendant_of(struct commit *, struct commit_list *);
int in_merge_bases(struct commit *, struct commit *);
diff --git a/shallow.c b/shallow.c
index a6547ca..975d699 100644
--- a/shallow.c
+++ b/shallow.c
@@ -317,3 +317,298 @@ void remove_nonexistent_ours_in_pack(struct shallow_info *info,
}
info->nr_ours = dst;
}
+
+define_commit_slab(ref_bitmap, uint32_t *);
+
+struct paint_info {
+ struct ref_bitmap ref_bitmap;
+ unsigned nr_bits;
+ char **slab;
+ char *free, *end;
+ unsigned slab_count;
+};
+
+static uint32_t *paint_alloc(struct paint_info *info)
+{
+ unsigned nr = (info->nr_bits + 31) / 32;
+ unsigned size = nr * sizeof(uint32_t);
+ void *p;
+ if (!info->slab_count || info->free + size > info->end) {
+ info->slab_count++;
+ info->slab = xrealloc(info->slab,
+ info->slab_count * sizeof(*info->slab));
+ info->free = xmalloc(COMMIT_SLAB_SIZE);
+ info->slab[info->slab_count - 1] = info->free;
+ info->end = info->free + COMMIT_SLAB_SIZE;
+ }
+ p = info->free;
+ info->free += size;
+ return p;
+}
+
+/*
+ * Given a commit SHA-1, walk down to parents until either SEEN,
+ * UNINTERESTING or BOTTOM is hit. Set the id-th bit in ref_bitmap for
+ * all walked commits.
+ */
+static void paint_down(struct paint_info *info, const unsigned char *sha1,
+ int id)
+{
+ unsigned int i, nr;
+ struct commit_list *head = NULL;
+ int bitmap_nr = (info->nr_bits + 31) / 32;
+ int bitmap_size = bitmap_nr * sizeof(uint32_t);
+ uint32_t *tmp = xmalloc(bitmap_size); /* to be freed before return */
+ uint32_t *bitmap = paint_alloc(info);
+ struct commit *c = lookup_commit_reference_gently(sha1, 1);
+ if (!c)
+ return;
+ memset(bitmap, 0, bitmap_size);
+ bitmap[id / 32] |= (1 << (id % 32));
+ commit_list_insert(c, &head);
+ while (head) {
+ struct commit_list *p;
+ struct commit *c = head->item;
+ uint32_t **refs = ref_bitmap_at(&info->ref_bitmap, c);
+
+ p = head;
+ head = head->next;
+ free(p);
+
+ /* XXX check "UNINTERESTING" from pack bitmaps if available */
+ if (c->object.flags & (SEEN | UNINTERESTING))
+ continue;
+ else
+ c->object.flags |= SEEN;
+
+ if (*refs == NULL)
+ *refs = bitmap;
+ else {
+ memcpy(tmp, *refs, bitmap_size);
+ for (i = 0; i < bitmap_nr; i++)
+ tmp[i] |= bitmap[i];
+ if (memcmp(tmp, *refs, bitmap_size)) {
+ *refs = paint_alloc(info);
+ memcpy(*refs, tmp, bitmap_size);
+ }
+ }
+
+ if (c->object.flags & BOTTOM)
+ continue;
+
+ if (parse_commit(c))
+ die("unable to parse commit %s",
+ sha1_to_hex(c->object.sha1));
+
+ for (p = c->parents; p; p = p->next) {
+ uint32_t **p_refs = ref_bitmap_at(&info->ref_bitmap,
+ p->item);
+ if (p->item->object.flags & SEEN)
+ continue;
+ if (*p_refs == NULL || *p_refs == *refs)
+ *p_refs = *refs;
+ commit_list_insert(p->item, &head);
+ }
+ }
+
+ nr = get_max_object_index();
+ for (i = 0; i < nr; i++) {
+ struct object *o = get_indexed_object(i);
+ if (o && o->type == OBJ_COMMIT) {
+ o->flags &= ~SEEN;
+ }
+ }
+
+ free(tmp);
+}
+
+static int mark_uninteresting(const char *refname,
+ const unsigned char *sha1,
+ int flags, void *cb_data)
+{
+ struct commit *commit = lookup_commit_reference_gently(sha1, 1);
+ if (!commit)
+ return 0;
+ commit->object.flags |= UNINTERESTING;
+ mark_parents_uninteresting(commit);
+ return 0;
+}
+
+static void post_assign_shallow(struct shallow_info *info,
+ struct ref_bitmap *ref_bitmap,
+ int *ref_status);
+/*
+ * Step 6(+7), associate shallow commits with new refs
+ *
+ * info->ref must be initialized before calling this function.
+ *
+ * If used is not NULL, it's an array of info->shallow->nr
+ * bitmaps. The n-th bit set in the m-th bitmap if ref[n] needs the
+ * m-th shallow commit from info->shallow.
+ *
+ * If used is NULL, "ours" and "theirs" are updated. And if ref_status
+ * is not NULL it's an array of ref->nr ints. ref_status[i] is true if
+ * the ref needs some shallow commits from either info->ours or
+ * info->theirs.
+ */
+void assign_shallow_commits_to_refs(struct shallow_info *info,
+ uint32_t **used, int *ref_status)
+{
+ unsigned char (*sha1)[20] = info->shallow->sha1;
+ struct sha1_array *ref = info->ref;
+ unsigned int i, nr;
+ int *shallow, nr_shallow = 0;
+ struct paint_info pi;
+
+ trace_printf_key(TRACE_KEY, "shallow: assign_shallow_commits_to_refs\n");
+ shallow = xmalloc(sizeof(*shallow) * (info->nr_ours + info->nr_theirs));
+ for (i = 0; i < info->nr_ours; i++)
+ shallow[nr_shallow++] = info->ours[i];
+ for (i = 0; i < info->nr_theirs; i++)
+ shallow[nr_shallow++] = info->theirs[i];
+
+ /*
+ * Prepare the commit graph to track what refs can reach what
+ * (new) shallow commits.
+ */
+ nr = get_max_object_index();
+ for (i = 0; i < nr; i++) {
+ struct object *o = get_indexed_object(i);
+ if (!o || o->type != OBJ_COMMIT)
+ continue;
+
+ o->flags &= ~(UNINTERESTING | BOTTOM | SEEN);
+ }
+
+ memset(&pi, 0, sizeof(pi));
+ init_ref_bitmap(&pi.ref_bitmap);
+ pi.nr_bits = ref->nr;
+
+ /*
+ * "--not --all" to cut short the traversal if new refs
+ * connect to old refs. If not (e.g. force ref updates) it'll
+ * have to go down to the current shallow commits.
+ */
+ head_ref(mark_uninteresting, NULL);
+ for_each_ref(mark_uninteresting, NULL);
+
+ /* Mark potential bottoms so we won't go out of bound */
+ for (i = 0; i < nr_shallow; i++) {
+ struct commit *c = lookup_commit(sha1[shallow[i]]);
+ c->object.flags |= BOTTOM;
+ }
+
+ for (i = 0; i < ref->nr; i++)
+ paint_down(&pi, ref->sha1[i], i);
+
+ if (used) {
+ int bitmap_size = ((pi.nr_bits + 31) / 32) * sizeof(uint32_t);
+ memset(used, 0, sizeof(*used) * info->shallow->nr);
+ for (i = 0; i < nr_shallow; i++) {
+ const struct commit *c = lookup_commit(sha1[shallow[i]]);
+ uint32_t **map = ref_bitmap_at(&pi.ref_bitmap, c);
+ if (*map)
+ used[shallow[i]] = xmemdupz(*map, bitmap_size);
+ }
+ /*
+ * unreachable shallow commits are not removed from
+ * "ours" and "theirs". The user is supposed to run
+ * step 7 on every ref separately and not trust "ours"
+ * and "theirs" any more.
+ */
+ } else
+ post_assign_shallow(info, &pi.ref_bitmap, ref_status);
+
+ clear_ref_bitmap(&pi.ref_bitmap);
+ for (i = 0; i < pi.slab_count; i++)
+ free(pi.slab[i]);
+ free(pi.slab);
+ free(shallow);
+}
+
+struct commit_array {
+ struct commit **commits;
+ int nr, alloc;
+};
+
+static int add_ref(const char *refname,
+ const unsigned char *sha1, int flags, void *cb_data)
+{
+ struct commit_array *ca = cb_data;
+ ALLOC_GROW(ca->commits, ca->nr + 1, ca->alloc);
+ ca->commits[ca->nr] = lookup_commit_reference_gently(sha1, 1);
+ if (ca->commits[ca->nr])
+ ca->nr++;
+ return 0;
+}
+
+static void update_refstatus(int *ref_status, int nr, uint32_t *bitmap)
+{
+ int i;
+ if (!ref_status)
+ return;
+ for (i = 0; i < nr; i++)
+ if (bitmap[i / 32] & (1 << (i % 32)))
+ ref_status[i]++;
+}
+
+/*
+ * Step 7, reachability test on "ours" at commit level
+ */
+static void post_assign_shallow(struct shallow_info *info,
+ struct ref_bitmap *ref_bitmap,
+ int *ref_status)
+{
+ unsigned char (*sha1)[20] = info->shallow->sha1;
+ struct commit *c;
+ uint32_t **bitmap;
+ int dst, i, j;
+ int bitmap_nr = (info->ref->nr + 31) / 32;
+ struct commit_array ca;
+
+ trace_printf_key(TRACE_KEY, "shallow: post_assign_shallow\n");
+ if (ref_status)
+ memset(ref_status, 0, sizeof(*ref_status) * info->ref->nr);
+
+ /* Remove unreachable shallow commits from "theirs" */
+ for (i = dst = 0; i < info->nr_theirs; i++) {
+ if (i != dst)
+ info->theirs[dst] = info->theirs[i];
+ c = lookup_commit(sha1[info->theirs[i]]);
+ bitmap = ref_bitmap_at(ref_bitmap, c);
+ if (!*bitmap)
+ continue;
+ for (j = 0; j < bitmap_nr; j++)
+ if (bitmap[0][j]) {
+ update_refstatus(ref_status, info->ref->nr, *bitmap);
+ dst++;
+ break;
+ }
+ }
+ info->nr_theirs = dst;
+
+ memset(&ca, 0, sizeof(ca));
+ head_ref(add_ref, &ca);
+ for_each_ref(add_ref, &ca);
+
+ /* Remove unreachable shallow commits from "ours" */
+ for (i = dst = 0; i < info->nr_ours; i++) {
+ if (i != dst)
+ info->ours[dst] = info->ours[i];
+ c = lookup_commit(sha1[info->ours[i]]);
+ bitmap = ref_bitmap_at(ref_bitmap, c);
+ if (!*bitmap)
+ continue;
+ for (j = 0; j < bitmap_nr; j++)
+ if (bitmap[0][j] &&
+ /* Step 7, reachability test at commit level */
+ !in_merge_bases_many(c, ca.nr, ca.commits)) {
+ update_refstatus(ref_status, info->ref->nr, *bitmap);
+ dst++;
+ break;
+ }
+ }
+ info->nr_ours = dst;
+
+ free(ca.commits);
+}
--
1.8.5.1.25.g8667982
Nguyễn Thái Ngọc Duy <pclouds@gmail.com>