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pacman/lib/libalpm/graph.h
Chantry Xavier 701a03dcdb Completely rework delta algorithm
Using the graph structures that Nagy set up for dependency sorting, we now
do a similar process for deltas. Load up all of the deltas into a graph
object on which we can then apply Dijkstra's algorithm, using the new weight
field of graph struct.
We initialize the nodes weight using the base files that we can use in our
filecache (both filename and md5sum must match). The algorithm then picks
the best path among those that can be resolved.

Note that this algorithm has a few advantages over the old one:
1. It is completely file agnostic. These delta chains do not have to consist
   of package files- this could be adopted to do delta-fied DBs.
2. It does not use the local_db anymore, or even care if a package or file
   is currently installed. Instead, it only looks in the filecache for files
   and packages that match delta chain entries.

Original-work-by: Dan McGee <dan@archlinux.org>
Signed-off-by: Chantry Xavier <shiningxc@gmail.com>
2008-04-26 11:36:01 -05:00

57 lines
1.6 KiB
C

/*
* graph.h - helpful graph structure and setup/teardown methods
*
* Copyright (c) 2002-2008 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 "alpm_list.h"
#include "util.h" /* MALLOC() */
#include "alpm.h"
struct __pmgraph_t {
char state; /* 0: untouched, -1: entered, other: leaving time */
void *data;
unsigned long int weight; /* weight of the node */
struct __pmgraph_t *parent; /* where did we come from? */
alpm_list_t *children;
alpm_list_t *childptr; /* points to a child in children list */
};
typedef struct __pmgraph_t pmgraph_t;
static pmgraph_t *_alpm_graph_new(void)
{
pmgraph_t *graph = NULL;
MALLOC(graph, sizeof(pmgraph_t), RET_ERR(PM_ERR_MEMORY, NULL));
if(graph) {
graph->state = 0;
graph->data = NULL;
graph->parent = NULL;
graph->children = NULL;
graph->childptr = NULL;
}
return(graph);
}
static void _alpm_graph_free(void *data)
{
pmgraph_t *graph = data;
alpm_list_free(graph->children);
free(graph);
}