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git/reachable.c
Jeff King 2824e1841b list-objects: pass full pathname to callbacks
When we find a blob at "a/b/c", we currently pass this to
our show_object_fn callbacks as two components: "a/b/" and
"c". Callbacks which want the full value then call
path_name(), which concatenates the two. But this is an
inefficient interface; the path is a strbuf, and we could
simply append "c" to it temporarily, then roll back the
length, without creating a new copy.

So we could improve this by teaching the callsites of
path_name() this trick (and there are only 3). But we can
also notice that no callback actually cares about the
broken-down representation, and simply pass each callback
the full path "a/b/c" as a string. The callback code becomes
even simpler, then, as we do not have to worry about freeing
an allocated buffer, nor rolling back our modification to
the strbuf.

This is theoretically less efficient, as some callbacks
would not bother to format the final path component. But in
practice this is not measurable. Since we use the same
strbuf over and over, our work to grow it is amortized, and
we really only pay to memcpy a few bytes.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-03-16 10:41:04 -07:00

200 lines
4.7 KiB
C

#include "cache.h"
#include "refs.h"
#include "tag.h"
#include "commit.h"
#include "blob.h"
#include "diff.h"
#include "revision.h"
#include "reachable.h"
#include "cache-tree.h"
#include "progress.h"
#include "list-objects.h"
struct connectivity_progress {
struct progress *progress;
unsigned long count;
};
static void update_progress(struct connectivity_progress *cp)
{
cp->count++;
if ((cp->count & 1023) == 0)
display_progress(cp->progress, cp->count);
}
static int add_one_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
{
struct object *object = parse_object_or_die(sha1, path);
struct rev_info *revs = (struct rev_info *)cb_data;
add_pending_object(revs, object, "");
return 0;
}
/*
* The traversal will have already marked us as SEEN, so we
* only need to handle any progress reporting here.
*/
static void mark_object(struct object *obj, const char *name, void *data)
{
update_progress(data);
}
static void mark_commit(struct commit *c, void *data)
{
mark_object(&c->object, NULL, data);
}
struct recent_data {
struct rev_info *revs;
unsigned long timestamp;
};
static void add_recent_object(const unsigned char *sha1,
unsigned long mtime,
struct recent_data *data)
{
struct object *obj;
enum object_type type;
if (mtime <= data->timestamp)
return;
/*
* We do not want to call parse_object here, because
* inflating blobs and trees could be very expensive.
* However, we do need to know the correct type for
* later processing, and the revision machinery expects
* commits and tags to have been parsed.
*/
type = sha1_object_info(sha1, NULL);
if (type < 0)
die("unable to get object info for %s", sha1_to_hex(sha1));
switch (type) {
case OBJ_TAG:
case OBJ_COMMIT:
obj = parse_object_or_die(sha1, NULL);
break;
case OBJ_TREE:
obj = (struct object *)lookup_tree(sha1);
break;
case OBJ_BLOB:
obj = (struct object *)lookup_blob(sha1);
break;
default:
die("unknown object type for %s: %s",
sha1_to_hex(sha1), typename(type));
}
if (!obj)
die("unable to lookup %s", sha1_to_hex(sha1));
add_pending_object(data->revs, obj, "");
}
static int add_recent_loose(const unsigned char *sha1,
const char *path, void *data)
{
struct stat st;
struct object *obj = lookup_object(sha1);
if (obj && obj->flags & SEEN)
return 0;
if (stat(path, &st) < 0) {
/*
* It's OK if an object went away during our iteration; this
* could be due to a simultaneous repack. But anything else
* we should abort, since we might then fail to mark objects
* which should not be pruned.
*/
if (errno == ENOENT)
return 0;
return error("unable to stat %s: %s",
sha1_to_hex(sha1), strerror(errno));
}
add_recent_object(sha1, st.st_mtime, data);
return 0;
}
static int add_recent_packed(const unsigned char *sha1,
struct packed_git *p, uint32_t pos,
void *data)
{
struct object *obj = lookup_object(sha1);
if (obj && obj->flags & SEEN)
return 0;
add_recent_object(sha1, p->mtime, data);
return 0;
}
int add_unseen_recent_objects_to_traversal(struct rev_info *revs,
unsigned long timestamp)
{
struct recent_data data;
int r;
data.revs = revs;
data.timestamp = timestamp;
r = for_each_loose_object(add_recent_loose, &data,
FOR_EACH_OBJECT_LOCAL_ONLY);
if (r)
return r;
return for_each_packed_object(add_recent_packed, &data,
FOR_EACH_OBJECT_LOCAL_ONLY);
}
void mark_reachable_objects(struct rev_info *revs, int mark_reflog,
unsigned long mark_recent,
struct progress *progress)
{
struct connectivity_progress cp;
/*
* Set up revision parsing, and mark us as being interested
* in all object types, not just commits.
*/
revs->tag_objects = 1;
revs->blob_objects = 1;
revs->tree_objects = 1;
/* Add all refs from the index file */
add_index_objects_to_pending(revs, 0);
/* Add all external refs */
for_each_ref(add_one_ref, revs);
/* detached HEAD is not included in the list above */
head_ref(add_one_ref, revs);
/* Add all reflog info */
if (mark_reflog)
add_reflogs_to_pending(revs, 0);
cp.progress = progress;
cp.count = 0;
/*
* Set up the revision walk - this will move all commits
* from the pending list to the commit walking list.
*/
if (prepare_revision_walk(revs))
die("revision walk setup failed");
traverse_commit_list(revs, mark_commit, mark_object, &cp);
if (mark_recent) {
revs->ignore_missing_links = 1;
if (add_unseen_recent_objects_to_traversal(revs, mark_recent))
die("unable to mark recent objects");
if (prepare_revision_walk(revs))
die("revision walk setup failed");
traverse_commit_list(revs, mark_commit, mark_object, &cp);
}
display_progress(cp.progress, cp.count);
}