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>

1 files changed, 1 insertions, 0 deletions

diff --git a/lib/libalpm/graph.h b/lib/libalpm/graph.h
index e3e40023..3078e25f 100644
--- a/lib/libalpm/graph.h
+++ b/lib/libalpm/graph.h
@@ -24,6 +24,7 @@
 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 */