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shallow.c: steps 6 and 7 to select new commits for .git/shallow

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Nguyễn Thái Ngọc Duy 2013-12-05 20:02:36 +07:00 committed by Junio C Hamano
parent 58babfffde
commit 8e277383e0
2 changed files with 297 additions and 0 deletions

View File

@ -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 *);

294
shallow.c
View File

@ -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);
}