git-commit-vandalism/replace_object.c
Stefan Beller d88f9fdf8b replace-object: move replace_map to object store
The relationship between an object X and another object Y that
replaces the object X is defined only within the scope of a
single repository.

The exception in reachability rule around these replacement objects
is also local to a repository (i.e. if traversal from refs reaches
X, then both X and Y are reachable and need to be kept from gc).

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-04-12 11:38:56 +09:00

74 lines
1.9 KiB
C

#include "cache.h"
#include "oidmap.h"
#include "object-store.h"
#include "replace-object.h"
#include "refs.h"
#include "repository.h"
#include "commit.h"
static int register_replace_ref(const char *refname,
const struct object_id *oid,
int flag, void *cb_data)
{
/* Get sha1 from refname */
const char *slash = strrchr(refname, '/');
const char *hash = slash ? slash + 1 : refname;
struct replace_object *repl_obj = xmalloc(sizeof(*repl_obj));
if (get_oid_hex(hash, &repl_obj->original.oid)) {
free(repl_obj);
warning("bad replace ref name: %s", refname);
return 0;
}
/* Copy sha1 from the read ref */
oidcpy(&repl_obj->replacement, oid);
/* Register new object */
if (oidmap_put(&the_repository->objects->replace_map, repl_obj))
die("duplicate replace ref: %s", refname);
return 0;
}
static void prepare_replace_object(void)
{
static int replace_object_prepared;
if (replace_object_prepared)
return;
for_each_replace_ref(register_replace_ref, NULL);
replace_object_prepared = 1;
if (!the_repository->objects->replace_map.map.tablesize)
check_replace_refs = 0;
}
/* We allow "recursive" replacement. Only within reason, though */
#define MAXREPLACEDEPTH 5
/*
* If a replacement for object oid has been set up, return the
* replacement object's name (replaced recursively, if necessary).
* The return value is either oid or a pointer to a
* permanently-allocated value. This function always respects replace
* references, regardless of the value of check_replace_refs.
*/
const struct object_id *do_lookup_replace_object(const struct object_id *oid)
{
int depth = MAXREPLACEDEPTH;
const struct object_id *cur = oid;
prepare_replace_object();
/* Try to recursively replace the object */
while (depth-- > 0) {
struct replace_object *repl_obj =
oidmap_get(&the_repository->objects->replace_map, cur);
if (!repl_obj)
return cur;
cur = &repl_obj->replacement;
}
die("replace depth too high for object %s", oid_to_hex(oid));
}