git/tag.c

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C
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#include "cache.h"
#include "tag.h"
#include "object-store.h"
#include "commit.h"
#include "tree.h"
#include "blob.h"
#include "alloc.h"
#include "gpg-interface.h"
#include "packfile.h"
const char *tag_type = "tag";
static int run_gpg_verify(const char *buf, unsigned long size, unsigned flags)
{
struct signature_check sigc;
size_t payload_size;
int ret;
memset(&sigc, 0, sizeof(sigc));
payload_size = parse_signature(buf, size);
if (size == payload_size) {
if (flags & GPG_VERIFY_VERBOSE)
write_in_full(1, buf, payload_size);
return error("no signature found");
}
ret = check_signature(buf, payload_size, buf + payload_size,
size - payload_size, &sigc);
if (!(flags & GPG_VERIFY_OMIT_STATUS))
print_signature_buffer(&sigc, flags);
signature_check_clear(&sigc);
return ret;
}
int gpg_verify_tag(const struct object_id *oid, const char *name_to_report,
unsigned flags)
{
enum object_type type;
char *buf;
unsigned long size;
int ret;
type = oid_object_info(the_repository, oid, NULL);
if (type != OBJ_TAG)
return error("%s: cannot verify a non-tag object of type %s.",
name_to_report ?
name_to_report :
find_unique_abbrev(oid, DEFAULT_ABBREV),
type_name(type));
buf = read_object_file(oid, &type, &size);
if (!buf)
return error("%s: unable to read file.",
name_to_report ?
name_to_report :
find_unique_abbrev(oid, DEFAULT_ABBREV));
ret = run_gpg_verify(buf, size, flags);
free(buf);
return ret;
}
struct object *deref_tag(struct repository *r, struct object *o, const char *warn, int warnlen)
{
struct object_id *last_oid = NULL;
while (o && o->type == OBJ_TAG)
if (((struct tag *)o)->tagged) {
last_oid = &((struct tag *)o)->tagged->oid;
o = parse_object(r, last_oid);
} else {
last_oid = NULL;
o = NULL;
}
if (!o && warn) {
if (last_oid && is_promisor_object(last_oid))
return NULL;
if (!warnlen)
warnlen = strlen(warn);
error("missing object referenced by '%.*s'", warnlen, warn);
}
return o;
}
upload-pack: avoid parsing tag destinations When upload-pack advertises refs, it dereferences any tags it sees, and shows the resulting sha1 to the client. It does this by calling deref_tag. That function must load and parse each tag object to find the sha1 of the tagged object. However, it also ends up parsing the tagged object itself, which is not strictly necessary for upload-pack's use. Each tag produces two object loads (assuming it is not a recursive tag), when it could get away with only a single one. Dropping the second load halves the effort we spend. The downside is that we are no longer verifying the resulting object by loading it. In particular: 1. We never cross-check the "type" field given in the tag object with the type of the pointed-to object. If the tag says it points to a tag but doesn't, then we will keep peeling and realize the error. If the tag says it points to a non-tag but actually points to a tag, we will stop peeling and just advertise the pointed-to tag. 2. If we are missing the pointed-to object, we will not realize (because we never even look it up in the object db). However, both of these are errors in the object database, and both will be detected if a client actually requests the broken objects in question. So we are simply pushing the verification away from the advertising stage, and down to the actual fetching stage. On my test repo with 120K refs, this drops the time to advertise the refs from ~3.2s to ~2.0s. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-01-06 19:18:01 +00:00
struct object *deref_tag_noverify(struct object *o)
{
while (o && o->type == OBJ_TAG) {
o = parse_object(the_repository, &o->oid);
upload-pack: avoid parsing tag destinations When upload-pack advertises refs, it dereferences any tags it sees, and shows the resulting sha1 to the client. It does this by calling deref_tag. That function must load and parse each tag object to find the sha1 of the tagged object. However, it also ends up parsing the tagged object itself, which is not strictly necessary for upload-pack's use. Each tag produces two object loads (assuming it is not a recursive tag), when it could get away with only a single one. Dropping the second load halves the effort we spend. The downside is that we are no longer verifying the resulting object by loading it. In particular: 1. We never cross-check the "type" field given in the tag object with the type of the pointed-to object. If the tag says it points to a tag but doesn't, then we will keep peeling and realize the error. If the tag says it points to a non-tag but actually points to a tag, we will stop peeling and just advertise the pointed-to tag. 2. If we are missing the pointed-to object, we will not realize (because we never even look it up in the object db). However, both of these are errors in the object database, and both will be detected if a client actually requests the broken objects in question. So we are simply pushing the verification away from the advertising stage, and down to the actual fetching stage. On my test repo with 120K refs, this drops the time to advertise the refs from ~3.2s to ~2.0s. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-01-06 19:18:01 +00:00
if (o && o->type == OBJ_TAG && ((struct tag *)o)->tagged)
o = ((struct tag *)o)->tagged;
else
o = NULL;
}
return o;
}
struct tag *lookup_tag(struct repository *r, const struct object_id *oid)
{
struct object *obj = lookup_object(r, oid);
if (!obj)
return create_object(r, oid, alloc_tag_node(r));
return object_as_type(r, obj, OBJ_TAG, 0);
}
static timestamp_t parse_tag_date(const char *buf, const char *tail)
{
const char *dateptr;
while (buf < tail && *buf++ != '>')
/* nada */;
if (buf >= tail)
return 0;
dateptr = buf;
while (buf < tail && *buf++ != '\n')
/* nada */;
if (buf >= tail)
return 0;
/* dateptr < buf && buf[-1] == '\n', so parsing will stop at buf-1 */
return parse_timestamp(dateptr, NULL, 10);
}
void release_tag_memory(struct tag *t)
{
free(t->tag);
t->tagged = NULL;
t->object.parsed = 0;
t->date = 0;
}
int parse_tag_buffer(struct repository *r, struct tag *item, const void *data, unsigned long size)
{
struct object_id oid;
char type[20];
const char *bufptr = data;
const char *tail = bufptr + size;
const char *nl;
if (item->object.parsed)
return 0;
item->object.parsed = 1;
if (size < the_hash_algo->hexsz + 24)
return -1;
if (memcmp("object ", bufptr, 7) || parse_oid_hex(bufptr + 7, &oid, &bufptr) || *bufptr++ != '\n')
return -1;
if (!starts_with(bufptr, "type "))
return -1;
bufptr += 5;
nl = memchr(bufptr, '\n', tail - bufptr);
if (!nl || sizeof(type) <= (nl - bufptr))
return -1;
memcpy(type, bufptr, nl - bufptr);
type[nl - bufptr] = '\0';
bufptr = nl + 1;
if (!strcmp(type, blob_type)) {
item->tagged = (struct object *)lookup_blob(r, &oid);
} else if (!strcmp(type, tree_type)) {
item->tagged = (struct object *)lookup_tree(r, &oid);
} else if (!strcmp(type, commit_type)) {
item->tagged = (struct object *)lookup_commit(r, &oid);
} else if (!strcmp(type, tag_type)) {
item->tagged = (struct object *)lookup_tag(r, &oid);
} else {
error("Unknown type %s", type);
item->tagged = NULL;
}
if (bufptr + 4 < tail && starts_with(bufptr, "tag "))
; /* good */
else
return -1;
bufptr += 4;
nl = memchr(bufptr, '\n', tail - bufptr);
if (!nl)
return -1;
item->tag = xmemdupz(bufptr, nl - bufptr);
bufptr = nl + 1;
if (bufptr + 7 < tail && starts_with(bufptr, "tagger "))
item->date = parse_tag_date(bufptr, tail);
else
item->date = 0;
return 0;
}
int parse_tag(struct tag *item)
{
enum object_type type;
void *data;
unsigned long size;
int ret;
if (item->object.parsed)
return 0;
data = read_object_file(&item->object.oid, &type, &size);
if (!data)
return error("Could not read %s",
oid_to_hex(&item->object.oid));
if (type != OBJ_TAG) {
free(data);
return error("Object %s not a tag",
oid_to_hex(&item->object.oid));
}
ret = parse_tag_buffer(the_repository, item, data, size);
free(data);
return ret;
}