/* * delta.c * * Copyright (c) 2007-2008 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 "config.h" #include <stdlib.h> #include <string.h> #include <limits.h> /* libalpm */ #include "delta.h" #include "alpm_list.h" #include "util.h" #include "log.h" #include "graph.h" /** \addtogroup alpm_deltas Delta Functions * @brief Functions to manipulate libalpm deltas * @{ */ const char SYMEXPORT *alpm_delta_get_from(pmdelta_t *delta) { ASSERT(delta != NULL, return(NULL)); return(delta->from); } const char SYMEXPORT *alpm_delta_get_from_md5sum(pmdelta_t *delta) { ASSERT(delta != NULL, return(NULL)); return(delta->from_md5); } const char SYMEXPORT *alpm_delta_get_to(pmdelta_t *delta) { ASSERT(delta != NULL, return(NULL)); return(delta->to); } const char SYMEXPORT *alpm_delta_get_to_md5sum(pmdelta_t *delta) { ASSERT(delta != NULL, return(NULL)); return(delta->to_md5); } const char SYMEXPORT *alpm_delta_get_filename(pmdelta_t *delta) { ASSERT(delta != NULL, return(NULL)); return(delta->delta); } const char SYMEXPORT *alpm_delta_get_md5sum(pmdelta_t *delta) { ASSERT(delta != NULL, return(NULL)); return(delta->delta_md5); } off_t SYMEXPORT alpm_delta_get_size(pmdelta_t *delta) { ASSERT(delta != NULL, return(-1)); return(delta->delta_size); } /** @} */ static alpm_list_t *delta_graph_init(alpm_list_t *deltas) { alpm_list_t *i, *j; alpm_list_t *vertices = NULL; /* create the vertices */ for(i = deltas; i; i = i->next) { char *fpath, *md5sum; pmgraph_t *v = _alpm_graph_new(); pmdelta_t *vdelta = i->data; vdelta->download_size = vdelta->delta_size; v->weight = LONG_MAX; /* determine whether the delta file already exists */ fpath = _alpm_filecache_find(vdelta->delta); md5sum = alpm_get_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(vdelta->from); md5sum = alpm_get_md5sum(fpath); if(fpath && md5sum && strcmp(md5sum, vdelta->from_md5) == 0) { v->weight = vdelta->download_size; } FREE(fpath); FREE(md5sum); v->data = vdelta; vertices = alpm_list_add(vertices, v); } /* compute the edges */ for(i = vertices; i; i = i->next) { pmgraph_t *v_i = i->data; pmdelta_t *d_i = v_i->data; /* loop a second time so we make all possible comparisons */ for(j = vertices; j; j = j->next) { pmgraph_t *v_j = j->data; pmdelta_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(strcmp(d_j->from, d_i->to) == 0 && strcmp(d_j->from_md5, d_i->to_md5) == 0) { v_i->children = alpm_list_add(v_i->children, v_j); } } v_i->childptr = v_i->children; } return(vertices); } static off_t delta_vert(alpm_list_t *vertices, const char *to, const char *to_md5, alpm_list_t **path) { alpm_list_t *i; pmgraph_t *v; while(1) { v = NULL; /* find the smallest vertice not visited yet */ for(i = vertices; i; i = i->next) { pmgraph_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) { pmgraph_t *v_c = v->childptr->data; pmdelta_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; } } v = NULL; off_t bestsize = 0; for(i = vertices; i; i = i->next) { pmgraph_t *v_i = i->data; pmdelta_t *d_i = v_i->data; if(strcmp(d_i->to, to) == 0 || strcmp(d_i->to_md5, to_md5) == 0) { if(v == NULL || v_i->weight < v->weight) { v = v_i; bestsize = v->weight; } } } alpm_list_t *rpath = NULL; while(v != NULL) { pmdelta_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 deltas the list of pmdelta_t * objects that a file has * @param to the file to start the search at * @param to_md5 the md5sum of the above named file * @param path the pointer to a list location where pmdelta_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_list_t *deltas, const char *to, const char *to_md5, alpm_list_t **path) { alpm_list_t *bestpath = NULL; alpm_list_t *vertices; off_t bestsize = LONG_MAX; ALPM_LOG_FUNC; if(deltas == NULL) { *path = NULL; return(bestsize); } _alpm_log(PM_LOG_DEBUG, "started delta shortest-path search\n"); vertices = delta_graph_init(deltas); bestsize = delta_vert(vertices, to, to_md5, &bestpath); _alpm_log(PM_LOG_DEBUG, "delta shortest-path search complete\n"); alpm_list_free_inner(vertices, _alpm_graph_free); alpm_list_free(vertices); *path = bestpath; return(bestsize); } /** Parses the string representation of a pmdelta_t object. * This function assumes that the string is in the correct format. * This format is as follows: * $oldfile $oldmd5 $newfile $newmd5 $deltafile $deltamd5 $deltasize * @param line the string to parse * @return A pointer to the new pmdelta_t object */ /* TODO this does not really belong here, but in a parsing lib */ pmdelta_t *_alpm_delta_parse(char *line) { pmdelta_t *delta; char *tmp = line, *tmp2; CALLOC(delta, 1, sizeof(pmdelta_t), RET_ERR(PM_ERR_MEMORY, NULL)); tmp2 = tmp; tmp = strchr(tmp, ' '); *(tmp++) = '\0'; STRDUP(delta->from, tmp2, RET_ERR(PM_ERR_MEMORY, NULL)); tmp2 = tmp; tmp = strchr(tmp, ' '); *(tmp++) = '\0'; STRDUP(delta->from_md5, tmp2, RET_ERR(PM_ERR_MEMORY, NULL)); tmp2 = tmp; tmp = strchr(tmp, ' '); *(tmp++) = '\0'; STRDUP(delta->to, tmp2, RET_ERR(PM_ERR_MEMORY, NULL)); tmp2 = tmp; tmp = strchr(tmp, ' '); *(tmp++) = '\0'; STRDUP(delta->to_md5, tmp2, RET_ERR(PM_ERR_MEMORY, NULL)); tmp2 = tmp; tmp = strchr(tmp, ' '); *(tmp++) = '\0'; STRDUP(delta->delta, tmp2, RET_ERR(PM_ERR_MEMORY, NULL)); tmp2 = tmp; tmp = strchr(tmp, ' '); *(tmp++) = '\0'; STRDUP(delta->delta_md5, tmp2, RET_ERR(PM_ERR_MEMORY, NULL)); delta->delta_size = atol(tmp); return(delta); } void _alpm_delta_free(pmdelta_t *delta) { FREE(delta->from); FREE(delta->from_md5); FREE(delta->to); FREE(delta->to_md5); FREE(delta->delta); FREE(delta->delta_md5); FREE(delta); } /* vim: set ts=2 sw=2 noet: */