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pacman/lib/libalpm/delta.c
Allan McRae ca43fdd92f Prefix alpm_loglevel_t members with ALPM
Signed-off-by: Allan McRae <allan@archlinux.org>
2011-07-02 02:01:38 +10:00

339 lines
8.4 KiB
C

/*
* delta.c
*
* Copyright (c) 2006-2011 Pacman Development Team <pacman-dev@archlinux.org>
* Copyright (c) 2007-2006 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 <stdlib.h>
#include <string.h>
#include <stdint.h> /* intmax_t */
#include <limits.h>
#include <sys/types.h>
#include <regex.h>
/* libalpm */
#include "delta.h"
#include "alpm_list.h"
#include "util.h"
#include "log.h"
#include "graph.h"
static alpm_list_t *graph_init(alpm_list_t *deltas, int reverse)
{
alpm_list_t *i, *j;
alpm_list_t *vertices = NULL;
/* create the vertices */
for(i = deltas; i; i = i->next) {
alpm_graph_t *v = _alpm_graph_new();
if(!v) {
alpm_list_free(vertices);
return NULL;
}
alpm_delta_t *vdelta = i->data;
vdelta->download_size = vdelta->delta_size;
v->weight = LONG_MAX;
v->data = vdelta;
vertices = alpm_list_add(vertices, v);
}
/* compute the edges */
for(i = vertices; i; i = i->next) {
alpm_graph_t *v_i = i->data;
alpm_delta_t *d_i = v_i->data;
/* loop a second time so we make all possible comparisons */
for(j = vertices; j; j = j->next) {
alpm_graph_t *v_j = j->data;
alpm_delta_t *d_j = v_j->data;
/* We want to create a delta tree like the following:
* 1_to_2
* |
* 1_to_3 2_to_3
* \ /
* 3_to_4
* If J 'from' is equal to I 'to', then J is a child of I.
* */
if((!reverse && strcmp(d_j->from, d_i->to) == 0) ||
(reverse && strcmp(d_j->to, d_i->from) == 0)) {
v_i->children = alpm_list_add(v_i->children, v_j);
}
}
v_i->childptr = v_i->children;
}
return vertices;
}
static void graph_init_size(alpm_handle_t *handle, alpm_list_t *vertices)
{
alpm_list_t *i;
for(i = vertices; i; i = i->next) {
char *fpath, *md5sum;
alpm_graph_t *v = i->data;
alpm_delta_t *vdelta = v->data;
/* determine whether the delta file already exists */
fpath = _alpm_filecache_find(handle, vdelta->delta);
md5sum = alpm_compute_md5sum(fpath);
if(fpath && md5sum && strcmp(md5sum, vdelta->delta_md5) == 0) {
vdelta->download_size = 0;
}
FREE(fpath);
FREE(md5sum);
/* determine whether a base 'from' file exists */
fpath = _alpm_filecache_find(handle, vdelta->from);
if(fpath) {
v->weight = vdelta->download_size;
}
FREE(fpath);
}
}
static void dijkstra(alpm_list_t *vertices)
{
alpm_list_t *i;
alpm_graph_t *v;
while(1) {
v = NULL;
/* find the smallest vertice not visited yet */
for(i = vertices; i; i = i->next) {
alpm_graph_t *v_i = i->data;
if(v_i->state == -1) {
continue;
}
if(v == NULL || v_i->weight < v->weight) {
v = v_i;
}
}
if(v == NULL || v->weight == LONG_MAX) {
break;
}
v->state = -1;
v->childptr = v->children;
while(v->childptr) {
alpm_graph_t *v_c = v->childptr->data;
alpm_delta_t *d_c = v_c->data;
if(v_c->weight > v->weight + d_c->download_size) {
v_c->weight = v->weight + d_c->download_size;
v_c->parent = v;
}
v->childptr = (v->childptr)->next;
}
}
}
static off_t shortest_path(alpm_list_t *vertices, const char *to, alpm_list_t **path)
{
alpm_list_t *i;
alpm_graph_t *v = NULL;
off_t bestsize = 0;
alpm_list_t *rpath = NULL;
for(i = vertices; i; i = i->next) {
alpm_graph_t *v_i = i->data;
alpm_delta_t *d_i = v_i->data;
if(strcmp(d_i->to, to) == 0) {
if(v == NULL || v_i->weight < v->weight) {
v = v_i;
bestsize = v->weight;
}
}
}
while(v != NULL) {
alpm_delta_t *vdelta = v->data;
rpath = alpm_list_add(rpath, vdelta);
v = v->parent;
}
*path = alpm_list_reverse(rpath);
alpm_list_free(rpath);
return bestsize;
}
/** Calculates the shortest path from one version to another.
* The shortest path is defined as the path with the smallest combined
* size, not the length of the path.
* @param handle the context handle
* @param deltas the list of alpm_delta_t * objects that a file has
* @param to the file to start the search at
* @param path the pointer to a list location where alpm_delta_t * objects that
* have the smallest size are placed. NULL is set if there is no path
* possible with the files available.
* @return the size of the path stored, or LONG_MAX if path is unfindable
*/
off_t _alpm_shortest_delta_path(alpm_handle_t *handle, alpm_list_t *deltas,
const char *to, alpm_list_t **path)
{
alpm_list_t *bestpath = NULL;
alpm_list_t *vertices;
off_t bestsize = LONG_MAX;
if(deltas == NULL) {
*path = NULL;
return bestsize;
}
_alpm_log(handle, ALPM_LOG_DEBUG, "started delta shortest-path search for '%s'\n", to);
vertices = graph_init(deltas, 0);
graph_init_size(handle, vertices);
dijkstra(vertices);
bestsize = shortest_path(vertices, to, &bestpath);
_alpm_log(handle, ALPM_LOG_DEBUG, "delta shortest-path search complete : '%jd'\n", (intmax_t)bestsize);
alpm_list_free_inner(vertices, _alpm_graph_free);
alpm_list_free(vertices);
*path = bestpath;
return bestsize;
}
static alpm_list_t *find_unused(alpm_list_t *deltas, const char *to, off_t quota)
{
alpm_list_t *unused = NULL;
alpm_list_t *vertices;
alpm_list_t *i;
vertices = graph_init(deltas, 1);
for(i = vertices; i; i = i->next) {
alpm_graph_t *v = i->data;
alpm_delta_t *vdelta = v->data;
if(strcmp(vdelta->to, to) == 0)
{
v->weight = vdelta->download_size;
}
}
dijkstra(vertices);
for(i = vertices; i; i = i->next) {
alpm_graph_t *v = i->data;
alpm_delta_t *vdelta = v->data;
if(v->weight > quota) {
unused = alpm_list_add(unused, vdelta->delta);
}
}
alpm_list_free_inner(vertices, _alpm_graph_free);
alpm_list_free(vertices);
return unused;
}
/** \addtogroup alpm_deltas Delta Functions
* @brief Functions to manipulate libalpm deltas
* @{
*/
alpm_list_t SYMEXPORT *alpm_pkg_unused_deltas(alpm_pkg_t *pkg)
{
off_t pkgsize = alpm_pkg_get_size(pkg);
alpm_list_t *unused = find_unused(
alpm_pkg_get_deltas(pkg),
alpm_pkg_get_filename(pkg),
pkgsize * MAX_DELTA_RATIO);
return unused;
}
/** @} */
/** Parses the string representation of a alpm_delta_t object.
* This function assumes that the string is in the correct format.
* This format is as follows:
* $deltafile $deltamd5 $deltasize $oldfile $newfile
* @param line the string to parse
* @return A pointer to the new alpm_delta_t object
*/
/* TODO this does not really belong here, but in a parsing lib */
alpm_delta_t *_alpm_delta_parse(char *line)
{
alpm_delta_t *delta;
char *tmp = line, *tmp2;
regex_t reg;
regcomp(&reg,
"^[^[:space:]]* [[:xdigit:]]{32} [[:digit:]]*"
" [^[:space:]]* [^[:space:]]*$",
REG_EXTENDED | REG_NOSUB | REG_NEWLINE);
if(regexec(&reg, line, 0, 0, 0) != 0) {
/* delta line is invalid, return NULL */
regfree(&reg);
return NULL;
}
regfree(&reg);
CALLOC(delta, 1, sizeof(alpm_delta_t), return NULL);
tmp2 = tmp;
tmp = strchr(tmp, ' ');
*(tmp++) = '\0';
STRDUP(delta->delta, tmp2, return NULL);
tmp2 = tmp;
tmp = strchr(tmp, ' ');
*(tmp++) = '\0';
STRDUP(delta->delta_md5, tmp2, return NULL);
tmp2 = tmp;
tmp = strchr(tmp, ' ');
*(tmp++) = '\0';
delta->delta_size = atol(tmp2);
tmp2 = tmp;
tmp = strchr(tmp, ' ');
*(tmp++) = '\0';
STRDUP(delta->from, tmp2, return NULL);
tmp2 = tmp;
STRDUP(delta->to, tmp2, return NULL);
return delta;
}
void _alpm_delta_free(alpm_delta_t *delta)
{
FREE(delta->delta);
FREE(delta->delta_md5);
FREE(delta->from);
FREE(delta->to);
FREE(delta);
}
alpm_delta_t *_alpm_delta_dup(const alpm_delta_t *delta)
{
alpm_delta_t *newdelta;
CALLOC(newdelta, 1, sizeof(alpm_delta_t), return NULL);
STRDUP(newdelta->delta, delta->delta, return NULL);
STRDUP(newdelta->delta_md5, delta->delta_md5, return NULL);
STRDUP(newdelta->from, delta->from, return NULL);
STRDUP(newdelta->to, delta->to, return NULL);
newdelta->delta_size = delta->delta_size;
newdelta->download_size = delta->download_size;
return newdelta;
}
/* vim: set ts=2 sw=2 noet: */