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git/tag.c
Sergey Vlasov 4a4e6fd74f Rework object refs tracking to reduce memory usage
Store pointers to referenced objects in a variable sized array instead
of linked list.  This cuts down memory usage of utilities which use
object references; e.g., git-fsck-objects --full on the git.git
repository consumes about 2 MB of memory tracked by Massif instead of
7 MB before the change.  Object refs are still the biggest consumer of
memory (57%), but the malloc overhead for a single block instead of a
linked list is substantially smaller.

Signed-off-by: Sergey Vlasov <vsu@altlinux.ru>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2005-11-15 11:42:29 -08:00

108 lines
2.6 KiB
C

#include "tag.h"
#include "cache.h"
const char *tag_type = "tag";
struct object *deref_tag(struct object *o, const char *warn, int warnlen)
{
while (o && o->type == tag_type)
o = parse_object(((struct tag *)o)->tagged->sha1);
if (!o && warn) {
if (!warnlen)
warnlen = strlen(warn);
error("missing object referenced by '%.*s'", warnlen, warn);
}
return o;
}
struct tag *lookup_tag(const unsigned char *sha1)
{
struct object *obj = lookup_object(sha1);
if (!obj) {
struct tag *ret = xmalloc(sizeof(struct tag));
memset(ret, 0, sizeof(struct tag));
created_object(sha1, &ret->object);
ret->object.type = tag_type;
return ret;
}
if (!obj->type)
obj->type = tag_type;
if (obj->type != tag_type) {
error("Object %s is a %s, not a tree",
sha1_to_hex(sha1), obj->type);
return NULL;
}
return (struct tag *) obj;
}
int parse_tag_buffer(struct tag *item, void *data, unsigned long size)
{
int typelen, taglen;
unsigned char object[20];
const char *type_line, *tag_line, *sig_line;
char type[20];
if (item->object.parsed)
return 0;
item->object.parsed = 1;
if (size < 64)
return -1;
if (memcmp("object ", data, 7) || get_sha1_hex(data + 7, object))
return -1;
type_line = data + 48;
if (memcmp("\ntype ", type_line-1, 6))
return -1;
tag_line = strchr(type_line, '\n');
if (!tag_line || memcmp("tag ", ++tag_line, 4))
return -1;
sig_line = strchr(tag_line, '\n');
if (!sig_line)
return -1;
sig_line++;
typelen = tag_line - type_line - strlen("type \n");
if (typelen >= 20)
return -1;
memcpy(type, type_line + 5, typelen);
type[typelen] = '\0';
taglen = sig_line - tag_line - strlen("tag \n");
item->tag = xmalloc(taglen + 1);
memcpy(item->tag, tag_line + 4, taglen);
item->tag[taglen] = '\0';
item->tagged = lookup_object_type(object, type);
if (item->tagged && track_object_refs) {
struct object_refs *refs = alloc_object_refs(1);
refs->ref[0] = item->tagged;
set_object_refs(&item->object, refs);
}
return 0;
}
int parse_tag(struct tag *item)
{
char type[20];
void *data;
unsigned long size;
int ret;
if (item->object.parsed)
return 0;
data = read_sha1_file(item->object.sha1, type, &size);
if (!data)
return error("Could not read %s",
sha1_to_hex(item->object.sha1));
if (strcmp(type, tag_type)) {
free(data);
return error("Object %s not a tag",
sha1_to_hex(item->object.sha1));
}
ret = parse_tag_buffer(item, data, size);
free(data);
return ret;
}