57 lines
1.5 KiB
C
57 lines
1.5 KiB
C
/* topology.c - Alpine Package Keeper (APK)
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* Topological sorting of database packages
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*
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* Copyright (C) 2011 Timo Teräs <timo.teras@iki.fi>
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* All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published
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* by the Free Software Foundation. See http://www.gnu.org/ for details.
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*/
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#include "apk_database.h"
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static int sort_pkg(apk_hash_item item, void *ctx)
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{
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struct apk_package *pkg = (struct apk_package *) item;
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unsigned int *sort_order = (unsigned int *) ctx;
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int i, j;
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/* Avoid recursion to same package */
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if (pkg->topology_sort != 0) {
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/* if pkg->topology_sort==-1 we have encountered a
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* dependency loop. Just silently ignore it and pick a
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* random topology sorting. */
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return 0;
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}
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pkg->topology_sort = -1;
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/* Sort all dependants before self */
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for (i = 0; i < pkg->depends->num; i++) {
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struct apk_dependency *dep = &pkg->depends->item[i];
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struct apk_name *name0 = dep->name;
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/* FIXME: sort names in order of ascending preference */
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for (j = 0; j < name0->pkgs->num; j++) {
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struct apk_package *pkg0 = name0->pkgs->item[j];
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if (!apk_dep_is_satisfied(dep, pkg0))
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continue;
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sort_pkg(pkg0, ctx);
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}
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}
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/* FIXME: install_if, provides, etc.*/
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/* Finally assign a topology sorting order */
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pkg->topology_sort = ++(*sort_order);
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return 0;
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}
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void apk_solver_sort(struct apk_database *db)
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{
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unsigned int sort_order = 0;
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apk_hash_foreach(&db->available.packages, sort_pkg, &sort_order);
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}
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