From 8e277383e0902551c0d5d3ef9591196de5a7078c Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Nguy=E1=BB=85n=20Th=C3=A1i=20Ng=E1=BB=8Dc=20Duy?= Date: Thu, 5 Dec 2013 20:02:36 +0700 Subject: [PATCH] shallow.c: steps 6 and 7 to select new commits for .git/shallow MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Signed-off-by: Nguyễn Thái Ngọc Duy Signed-off-by: Junio C Hamano --- commit.h | 3 + shallow.c | 294 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 297 insertions(+) diff --git a/commit.h b/commit.h index 9ead93bffb..69bca3e4be 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 ecd950fd04..fb6069ba0c 100644 --- a/shallow.c +++ b/shallow.c @@ -317,3 +317,297 @@ 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); +}