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pacman/lib/libalpm/cache.c
Dan McGee 6cebd4e602 Complete rework of package accessor logic
Hopefully we've finally arrived at package handling nirvana, or at least
this commit will get us a heck of a lot closer. The former method of getting
the depends list for a package was the following:

1. call alpm_pkg_get_depends()
2. this method would check if the package came from the cache
3. if so, ensure our cache level is correct, otherwise call db_load
4. finally return the depends list

Why did this suck? Because getting the depends list from the package
shouldn't care about whether the package was loaded from a file, from the
'package cache', or some other system which we can't even use because the
damn thing is so complicated. It should just return the depends list.

So what does this commit change? It adds a pointer to a struct of function
pointers to every package for all of these 'package operations'  as I've
decided to call them (I know, sounds completely straightforward, right?). So
now when we call an alpm_pkg_get-* function, we don't do any of the cache
logic or anything else there- we let the actual backend handle it by
delegating all work to the method at pkg->ops->get_depends.

Now that be_package has achieved equal status with be_files, we can treat
packages from these completely different load points differently. We know a
package loaded from a zip file will have all of its fields populated, so
we can set up all its accessor functions to be direct accessors. On the
other hand, the packages loaded from the local and sync DBs are not always
fully-loaded, so their accessor functions are routed through the same logic
as before.

Net result? More code. However, this code now make it roughly 52 times
easier to open the door to something like a read-only tar.gz database
backend.

Are you still reading? I'm impressed. Looking at the patch will probably be
clearer than this long-winded explanation.

Signed-off-by: Dan McGee <dan@archlinux.org>
[Allan: rebase and adjust]
Signed-off-by: Allan McRae <allan@archlinux.org>
2010-10-13 23:53:18 +10:00

282 lines
5.8 KiB
C

/*
* cache.c
*
* Copyright (c) 2006-2010 Pacman Development Team <pacman-dev@archlinux.org>
* Copyright (c) 2002-2006 by Judd Vinet <jvinet@zeroflux.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "config.h"
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
/* libalpm */
#include "cache.h"
#include "alpm_list.h"
#include "log.h"
#include "alpm.h"
#include "util.h"
#include "package.h"
#include "group.h"
#include "db.h"
/* Returns a new package cache from db.
* It frees the cache if it already exists.
*/
int _alpm_db_load_pkgcache(pmdb_t *db)
{
ALPM_LOG_FUNC;
if(db == NULL) {
return(-1);
}
_alpm_db_free_pkgcache(db);
_alpm_log(PM_LOG_DEBUG, "loading package cache for repository '%s'\n",
db->treename);
if(_alpm_db_populate(db) == -1) {
_alpm_log(PM_LOG_DEBUG,
"failed to load package cache for repository '%s'\n", db->treename);
return(-1);
}
db->pkgcache_loaded = 1;
return(0);
}
void _alpm_db_free_pkgcache(pmdb_t *db)
{
ALPM_LOG_FUNC;
if(db == NULL || !db->pkgcache_loaded) {
return;
}
_alpm_log(PM_LOG_DEBUG, "freeing package cache for repository '%s'\n",
db->treename);
alpm_list_free_inner(db->pkgcache, (alpm_list_fn_free)_alpm_pkg_free);
alpm_list_free(db->pkgcache);
db->pkgcache = NULL;
db->pkgcache_loaded = 0;
_alpm_db_free_grpcache(db);
}
alpm_list_t *_alpm_db_get_pkgcache(pmdb_t *db)
{
ALPM_LOG_FUNC;
if(db == NULL) {
return(NULL);
}
if(!db->pkgcache_loaded) {
_alpm_db_load_pkgcache(db);
}
/* hmmm, still NULL ?*/
if(!db->pkgcache) {
_alpm_log(PM_LOG_DEBUG, "warning: pkgcache is NULL for db '%s'\n", db->treename);
}
return(db->pkgcache);
}
/* "duplicate" pkg then add it to pkgcache */
int _alpm_db_add_pkgincache(pmdb_t *db, pmpkg_t *pkg)
{
pmpkg_t *newpkg;
ALPM_LOG_FUNC;
if(db == NULL || !db->pkgcache_loaded || pkg == NULL) {
return(-1);
}
newpkg = _alpm_pkg_dup(pkg);
if(newpkg == NULL) {
return(-1);
}
_alpm_log(PM_LOG_DEBUG, "adding entry '%s' in '%s' cache\n",
alpm_pkg_get_name(newpkg), db->treename);
db->pkgcache = alpm_list_add_sorted(db->pkgcache, newpkg, _alpm_pkg_cmp);
_alpm_db_free_grpcache(db);
return(0);
}
int _alpm_db_remove_pkgfromcache(pmdb_t *db, pmpkg_t *pkg)
{
void *vdata;
pmpkg_t *data;
ALPM_LOG_FUNC;
if(db == NULL || !db->pkgcache_loaded || pkg == NULL) {
return(-1);
}
_alpm_log(PM_LOG_DEBUG, "removing entry '%s' from '%s' cache\n",
alpm_pkg_get_name(pkg), db->treename);
db->pkgcache = alpm_list_remove(db->pkgcache, pkg, _alpm_pkg_cmp, &vdata);
data = vdata;
if(data == NULL) {
/* package not found */
_alpm_log(PM_LOG_DEBUG, "cannot remove entry '%s' from '%s' cache: not found\n",
alpm_pkg_get_name(pkg), db->treename);
return(-1);
}
_alpm_pkg_free(data);
_alpm_db_free_grpcache(db);
return(0);
}
pmpkg_t *_alpm_db_get_pkgfromcache(pmdb_t *db, const char *target)
{
ALPM_LOG_FUNC;
if(db == NULL) {
return(NULL);
}
alpm_list_t *pkgcache = _alpm_db_get_pkgcache(db);
if(!pkgcache) {
_alpm_log(PM_LOG_DEBUG, "warning: failed to get '%s' from NULL pkgcache\n",
target);
return(NULL);
}
return(_alpm_pkg_find(pkgcache, target));
}
/* Returns a new group cache from db.
*/
int _alpm_db_load_grpcache(pmdb_t *db)
{
alpm_list_t *lp;
ALPM_LOG_FUNC;
if(db == NULL) {
return(-1);
}
_alpm_log(PM_LOG_DEBUG, "loading group cache for repository '%s'\n",
db->treename);
for(lp = _alpm_db_get_pkgcache(db); lp; lp = lp->next) {
const alpm_list_t *i;
pmpkg_t *pkg = lp->data;
for(i = alpm_pkg_get_groups(pkg); i; i = i->next) {
const char *grpname = i->data;
alpm_list_t *j;
pmgrp_t *grp = NULL;
int found = 0;
/* first look through the group cache for a group with this name */
for(j = db->grpcache; j; j = j->next) {
grp = j->data;
if(strcmp(grp->name, grpname) == 0
&& !alpm_list_find_ptr(grp->packages, pkg)) {
grp->packages = alpm_list_add(grp->packages, pkg);
found = 1;
break;
}
}
if(found) {
continue;
}
/* we didn't find the group, so create a new one with this name */
grp = _alpm_grp_new(grpname);
grp->packages = alpm_list_add(grp->packages, pkg);
db->grpcache = alpm_list_add(db->grpcache, grp);
}
}
db->grpcache_loaded = 1;
return(0);
}
void _alpm_db_free_grpcache(pmdb_t *db)
{
alpm_list_t *lg;
ALPM_LOG_FUNC;
if(db == NULL || !db->grpcache_loaded) {
return;
}
_alpm_log(PM_LOG_DEBUG, "freeing group cache for repository '%s'\n",
db->treename);
for(lg = db->grpcache; lg; lg = lg->next) {
_alpm_grp_free(lg->data);
lg->data = NULL;
}
FREELIST(db->grpcache);
db->grpcache_loaded = 0;
}
alpm_list_t *_alpm_db_get_grpcache(pmdb_t *db)
{
ALPM_LOG_FUNC;
if(db == NULL) {
return(NULL);
}
if(!db->grpcache_loaded) {
_alpm_db_load_grpcache(db);
}
return(db->grpcache);
}
pmgrp_t *_alpm_db_get_grpfromcache(pmdb_t *db, const char *target)
{
alpm_list_t *i;
ALPM_LOG_FUNC;
if(db == NULL || target == NULL || strlen(target) == 0) {
return(NULL);
}
for(i = _alpm_db_get_grpcache(db); i; i = i->next) {
pmgrp_t *info = i->data;
if(strcmp(info->name, target) == 0) {
return(info);
}
}
return(NULL);
}
/* vim: set ts=2 sw=2 noet: */